Specification
A SUPPORT FOR SUPPORTING A STRUCTURE ON A SURFACE
Field of the Invention
The present invention broadly relates to a support
for supporting a structure on a surface, for example, to a
support having at least two self-adjusting support
elements.
Background of the Invention
Structures such as tables, ladders and tripods have
legs for positioning on a surface. If not all of the legs
contact the surface, the position of the structure will be
unstable. The position of the structure can be made more
stable by adjusting the heights of individual legs. This
is often done with a screw-type mechanism commonly found
at the bottom of the legs.
Alternatively, all of the legs may be in contact with
the surface but the structure may not have a desired
orientation relative to the surface. Again, the position
of the structure relative to the surface may be adjusted
by adjusting the height of the individual legs with the
same type of screw mechanism. Other structures such as
large machines and houses may contact the ground directly
without legs or through supporting beams or a base plate.
Level or tilt adjustment of these large structures
typically is done with individually controlled jacks or
wedges.
In any case the adjustment of the position of the
structure typically is cumbersome and time consuming.
There is a need for a technically advanced solution.
Pistons have been utilised to stabilise structures
such as ladders, tripods and tables. Generally one piston
is associated with each leg of the structure. The pistons
are in fluid communication. Thus the pistons can be
utilised to together adjust the position of individual
support legs. When the position of the structure is
considered stable the pistons are manually isolated so no
further adjustment occurs. These systems do not provide
self-adj usting support.
Summary of the Invention
The present invention provides in a first aspect a
support for supporting a structure on a surface, the
support comprising at least one support element, the or
each support element comprising:
a piston,
a cylinder in which the piston is moveable, and
a braking means for maintaining the piston in a
position that is stable relative to the cylinder,
wherein the piston and the cylinder are arranged so
that a loading associated with the structure effects an
adjustment of the support element,
and wherein an increase in hydraulic pressure within
the cylinder effected by the loading associated with the
structure activates the braking means.
The or each cylinder typically has a fluid
inlet/outlet and typically is arranged so that an amount
of fluid flowing through the inlet/outlet controls the
movement of the or each piston relative to the or each
cylinder. The or each cylinder typically has an opening
positioned so that in use the movement of the or each
piston effects a movement of a surface contact portion of
the or each support element relative to the surface.
The support typically has at least two support
elements. In this case the fluid inlet/outlets typically
are interconnected by at least one fluid conduit so that
the fluid can flow between the inlet/outlets. The support
typically is arranged so that in use, when the support is
placed on the surface and at least one of the surface
contact portions does not contact the surface, a movement
of the pistons relative to the cylinders is effected that
adjusts the positions of the surface contact portions
relative to the surface.
The support typically is self-adjusting which has a
significant practical advantage. For example, the
structure with support may be placed on the surface and at
least one of the surface contact portion may contact the
surface while at least one other contact portion may not
contact the surface. The surface may be uneven or the
structure may be placed on the surface in an angled
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position. The structure typipally is arranged so that the
or each piston associated with the surface contact portion
that contacts the surface moves inwardly and typically
pushes fluid into the or each cylinders associated with
the or each other contact portion that does not contact
the surface which typically effects movement of each
contact portion.
Alternatively, all contact portions may contact the
surface but the structure may be tilted to, for example,
the rear of the structure. In this case the loading on the
or each rear support element would increase and the
loading on the or each front support element would
decrease. The support is typically arranged so that the or
each piston associated with the increased loading moves
inwardly and typically pushes fluid into the or each
cylinder associated with the or each support element
associated with the decreased loading.
The support typically is arranged so that, after
adjustment and if all contact portions contact the
surface, the loading on the support elements effects an
increase in hydraulic pressure within the or each cylinder
which actuates the braking means and inhibits movement of
the pistons so that the structure is in an adjusted and
stable position.
In one embodiment each piston comprises the surface
contact portion arranged to contact the surface.
Alternatively, the surface contact portion may be a
component that is either in direct or indirect contact
with the piston and that may be positioned so that a
movement of the pistons relative to the cylinder effects a
movement of the surface contact portions.
In a variation of this embodiment each cylinder may
comprise a surface contact portion arranged-to contact the
surface. Alternatively, the surface contact portion may be
a component that is either in direct or indirect contact
with the cylinder and that may be positioned so that a
movement of the cylinder relative to the pistons effects a
movement of the surface contact portions.
In a specific embodiment the support is arranged so
that the pistons move relative to the cylinders, until an
increase of pressure in the cylinders actuates the braking
means. For example, this may be the case when the pressure
in all cylinders has the same level.
The braking means of each support element may be
hydraulic. For example, the piston of each support element
may have a cavity arranged so that in use fluid can
penetrate from the inlet/outlet into the cylinder and into
the cavity. In one specific embodiment of the present
invention the piston is elongate and at least one side
portion has at least one recess that is linked to the
cavity. A brake-pad or brake-cylinder typically is
positioned in the or each recess of the piston and
arranged so that, If fluid penetrates into the cavity, the
or each brake-pad or brake-cylinder is in use moved
towards an interior wall of the cylinder. In this case the
braking means typically is arranged so that an increase of
the fluid pressure in the cavity increases the pressure of
the or each brake-pad or brake-cylinder against the
interior wall of the cylinder and thereby acts against the
moveability of the piston in the cylinder.
In a variation of this embodiment the cylinder may
have at least one recess in an interior side wall. The or
each brake pad or brake cylinder may be positioned in the
or each recess of the interior side wall and arranged to
push against the piston.
The braking means of each support element may also be
mechanical. For example, the support element may comprise
a brake portion which typically is moveable relative to
the cylinder and with the piston until the movement of the
surface contact portion is restricted, for example by
contact with the surface. For example, the brake portion
may be the surface contact portion. In this case the
piston and brake portion may be arranged so that, when the
movement of the brake portion is restricted, a further
movement of the piston relative to the cylinder activates
the braking means. For example, the braking means may be
arranged so that a movement of the brake portion against
an interior wall of the cylinder may be effected. In this
case the piston and the braking means may have wedging
portions which in use Effect the movement of the brake
portion against the interior wall of the cylinder.
Further, the brake portion may have one or more teeth on
an exterior portion that are arranged to interlock with
one or more teeth on the interior wall of the cylinder if
the brake portion, is pushed against the interior wall of
the cylinder.
In one embodiment of the present invention the
support comprises a reservoir for the fluid that is
interconnected with the fluid inlet/outlets and that is in
use typically positioned above the cylinders. The
cylinders and fluid inlet/outlets are typically connected
so that a closed system is formed which may comprise the
reservoir.
The support may also comprise a valve arranged to
receive a hydraulic liquid. In this case the support is
typically arranged so that, when the valve is opened and
the hydraulic liquid is pumped into the support, the or
each support element lifts the structure from a first
level to a second level.
For example, the structure may be a furniture item
such as a table, building such as a house, or any other
structure that may be placed on a surface including
airborne vehicles. The structure typically has three or
four support elements, but may alternatively have any
number of support elements.
The present invention provides in a second aspect an
adjustable support for supporting a structure on an
underlying surface, the support comprising a piston
cylinder assembly, the piston being moveable relative to
the cylinder, with one of the piston or cylinder being
connected to, or forming part of, the structure and the
other being associated with a contact portion operative to
engage the underlying surface, and braking means for
inhibiting movement of the piston relative to the
cylinder, wherein the braking means is operative in
response to the application of predetermined loading
conditions to a portion of the support.
The present invention provides in a third aspect a
braking system for a piston and cylinder assembly, the
braking system comprising a braking means adapted to be
actuated by an increase in fluid pressure within the
cylinder.
In one embodiment of the third aspect the piston has
a cavity arranged so that in use fluid can penetrate from
an inlet/outlet into the cylinder and into the cavity and
wherein at least one side portion of the piston has at
least one recess that is linked to the cavity. In this
embodiment a brake-pad or brake-cylinder is positioned in
the or each recess of the piston and arranged so that if
fluid penetrates into the cavity the or each brake-pad or
brake-cylinder is in use moved towards an interior wall of
the cylinder. The braking means may then be arranged so
that an increase of the fluid pressure in the cavity
increases the pressure of the or each brake-pad or brakecylinder
against the interior wall of the cylinder and
thereby acts against the moveability of the piston in the
cylinder.
In a second embodiment of the third aspect the
braking system includes a cavity separating a piston plate
from the piston. The cavity may contain resistance means
such that in use the piston plate and piston are retained
in a distal position relative to one another and on an
increase in fluid pressure within the cylinder the piston
plate and piston move proximal to one another, actuating
braking means. The cavity further contains at least one
inlet/outlet extension extending through at least a
portion of the cavity so that in use fluid can penetrate
from an inlet/outlet into the inlet/outlet extension and
into the cylinder, and means for disrupting penetration of
fluid through the inlet/outlet extension and into the
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cylinder upon an increase in fluid pressure within the
cylinder, actuating braking of the piston relative to the
cylinder.
In one form the resistance means comprises a spring
or a fluid-filled bladder.
In one form the inlet/outlet extension comprises a
tube extending through the cavity and into the cylinder.
In one form the tube is flexible and at least one of
the piston plate and piston comprises crimpers extending
into the cavity such that when the fluid pressure in the
cylinder increases and the piston plate and piston move
proximal to one another the crimpers compress the flexible
tube and disrupt fluid flow into the cylinder.
In another form the tube includes a valve such that
when the fluid pressure in the cylinder increases and the
piston plate and piston move proximal to one another the
valve disrupts fluid flow through the tube and into the
cylinder.
In one form the tube includes a first member
extending therethrough and the cavity contains a second
member, the first member including a flow aperture to
allow fluid penetration through the tube, the second
member being adapted to move between an open position and
a closed position such that in the closed position the
flow aperture is blocked by the second member, disrupting
fluid penetration through the tube and into the cylinder.
In one form the inlet/outlet extension comprises a
helical flexible tube portion extending through at least a
portion of the cylinder.
In a further embodiment of the third aspect the
braking means is situated between two or more support
elements and comprises at least two fluid reservoirs
adapted such that, when the pressure in at least one fluid
reservoir is below a threshold level, the fluid reservoirs
are in fluid communication and, when the pressure in all
fluid reservoirs is above a threshold level, the fluid
reservoirs are not in fluid communication.
In a fourth aspect, the present invention provides a
support for supporting a structure on a surface, the
support comprising at least one support element, the or
each support element comprising a piston, a cylinder in
which the piston is moveable, and a braking means for
maintaining the piston in a position that is stable
relative to the cylinder, wherein the piston and the
cylinder are arranged so that a loading associated with
the structure effects an adjustment of the support
element, and wherein the loading associated with the
structure activates the braking means if the raoveability
of a surface contact portion of the support element is
reduced below a threshold value.
Brief Description of the Drawings
Figures 1A and IB show schematic representations of a
support for a structure according to an embodiment of the
present invention,
Figure 2 shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention.
Figure 3 shows a schematic representation of a
support element for supporting a structure according to
another embodiment of the present invention,
Figure 4 shows a schematic representation of a
support element for supporting a structure according to a
further embodiment of the present invention,
Figure 5 shows a schematic representation of a
support element for supporting a structure according to
yet another embodiment of the present invention,
Figure 6 shows a perspective view of a representation
of a support for a structure according to an embodiment of
the present invention/
Figure 7 shows a front perspective view of a
representation of the support for a structure of Figure 6,
Figure 8 and 9 show a schematic representation of a
support for a structure according to an embodiment of the
present invention,
Figure 10 shows a schematic representation of the
support for a structure of Figures 10A and 10B in use,
Figure 11 shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention,
Figure 12 shows a schematic representation of the
support element for supporting a structure of Figure 12,
Figure 13 shows a schematic representation of the
support element for supporting a structure of Figure 12,
Figure 14 shows a schematic representation of the
support element for supporting a structure of Figure 12,
Figure 15shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention,
Figures 16 shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention,
Figure 17 shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention,
Figure 18 shows a schematic representation of a ball
valve of the support element for supporting a structure of
Figure 17,
Figure 19 shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention,
Figure 20 shows a schematic representation of a
support element for supporting a structure according to an
embodiment of the present invention,
Figure 21 shows a schematic representation of a valve
element according to an embodiment of the present
invention,
Figure 22 shows a schematic representation of a valve
element according to an embodiment of the present
invention,
Figure 23 shows a schematic representation of a valve
element according to an embodiment of the present
invention,
Figure 24 shows a schematic representation of a valve
element according to an embodiment of the present
invention,
Figure 25 shows a schematic representation of a valve
element according to an embodiment of the present
invention.
Figure 26 shows a schematic representation of a
system using the embodiment of Figure 25/
Figure 27 shows a schematic representation of a
support element according to an embodiment of the present
invention in use in a helicopter, and
Figure 28 shows a schematic representation of a
support element according to an embodiment of the present
invention in use in a helicopter.
Detailed Description of Specific Embodiments
Referring initially to Figures 1A and IB, a support
for a structure according to an embodiment of the present
invention is now described. Figure 1A shows the support 10
supporting a structure 16. The support comprises in this
embodiment 3 or 4 support elements though Figure 1A only
shows two of the support elements. Each support element 12
and 14 comprises a cylinder 18 and a piston 20. The
cylinders 18 each have a fluid inlet/outlet 22 which is
connected to the fluid inlet/outlet 22 of the other
support element by tube 24. The cylinder 18 is filled with
fluid. The amount of fluid that flows through the
inlet/outlet 22 determines the movement of the pistons 20
in the cylinders 18. As each fluid inlet/outlet 22 is
interconnected to another fluid inlet/outlet 22, an upward
movement of one of the pistons in the respective cylinder
moves the fluid through the tube 24 and hence effects a
downward movement of the other cylinder 20.
When the support is placed on surface 26, the weight
of the structure effects an upward movement of piston 20
in support element 14 and a downward movement of piston 20
in support element 12. The movements of the pistons
therefore adjust the height of support elements 12 and 14.
Once both pistons have reached the adjustment positions,
the loading associated with the structure 16 effects a
pressure increase within the cylinders and a brake (not
shown) secures the pistons in the cylinders in the
stationary position. As the adjustment and the securing of
the pistons in the cylinders happens automatically, the
support is self-adjusting.
In this embodiment, the support 10 also includes a
valve 25 arranged to receive a hydraulic liquid. When the
valve 25 is open fluid can move between the support 12 and
the support 14.
The valve 25 is adapted to restrict fluid transfer
such that when the fluid on both sides of the valve 25 is
pressurised above a threshold value fluid flow through the
valve 25 is limited or prevented. In contrast when the
fluid pressure on one side of the valve 25 is below the
threshold value, the valve 25 is adapted to allow fluid
transfer. When fluid transfer occurs, the pressure on both
sides of the valve 25 falls to below the preset limit and
the interconnected valves 25 of each support element 12,
14 will open to allow fluid transfer.
This allows the support element 30 to self-adjust
upon a change in loading. That is when any one leg is
unloaded leg height adjustment is allowed by the opening
of the valves 25 and flow of fluid through the tube 24.
Figure IB shows a variation of the embodiment shown
in Figure 1A. In this case the structure that is supported
by the support 26 is a table 26.
Figure 2 shows detail of a support element 30 for
supporting a structure, such as support elements 12 or 14
shown in Figures 1A and IB. The support element 30
comprises a cylinder 32 in which a piston 34 is guided.
The cylinder 32 has a fluid inlet/outlet opening 36 for
receiving and ejecting fluid 38, such as a hydraulic
liquid or water. The piston 34 has a seal 35 for sealing
the fluid 38 in the cylinder 32. The fluid inlet/outlet 36
is connected to another such fluid inlet/outlet of another
support element (not shown).
In the embodiment shown in Figure 2, the piston 34
includes a cavity 40 having openings 42 and 44 at the side
portions of the piston 34. In the openings 42 and 44 brake
cylinders 46 and 48 are guided and if the fluid pressure
in the cylinder 32 is above a threshold level, the brake
cylinders 46 and 48 are pushed against the interior wall
of the cylinder 32 so as to position the piston 34 in a
stationary position relative the cylinder 32. The cylinder
32 also has a thread 33 for mounting on a structure. This
mechanism operates as a valve in the support element 30.
Typically, a structure such as a table is supported
by 3 or 4 of the support elements 30 which are
interconnected. After placing the table on a surface, the
support elements typically adjust for an uneven surface
and fluid flows between the cylinders until the pistons
are in the adjustment position. The weight of the
structure will increase the pressure above the threshold
pressure and the brake cylinders 46 and 48 move against
the interior wall of the cylinder 32 so as to position the
pistons stationary. Consequently, the table will then have
a stable position.
Figure 3 shows a support element 50 for supporting a
structure according to another embodiment of the
invention. Again, the support element 50 may function as
support element 12 or 14 in the embodiment shown in
Figures 1A and IB and described above. The support
element 50 comprises a cylinder 52 in which a piston 54 is
guided. The cylinder 52 has a fluid inlet/outlet opening
56 for receiving and ejecting fluid 58, such as a
hydraulic liquid or water. The piston 54 has a seal 55 for
sealing the fluid in the cylinder 52. The fluid
inlet/outlet 56 is connected to another such fluid
inlet/outlet of another support element (not shown). In
this embodiment the support element 50 comprises another
piston 60 positioned below the piston 54. The piston 54
has a cylindrical projection 62 which is received by a
corresponding cylindrical bore 66 of the piston 60. The
piston 60 has a cavity 68 which is filled with a hydraulic
fluid 58 and which has openings 70 and 72. Brake cylinders
74 and 76 are guided in the openings 70 and 72 and, if the
fluid pressure in the cavity 68 is above a threshold
level, the brake cylinders 74 and 76 are pushed against
the interior wall of the cylinder 52 so as to position the
piston 60 r and thereby the piston 54, in a stationary
position relative the cylinder 52. The fluid pressure in
the cavity 68 increases in response to the loading
associated with the structure. That is, if the moveability
of a surface contact portion 102 of the support element 50
is reduced below a threshold value by the loading
associated with the structure.
The cylinder 32 also has a thread 77 for mounting on
a structure.
Further, the support element 50 comprises a
compression spring 79 positioned around the projection 62.
When the structure is lifted and therefore the loading on
the support element 50 is reduced, the spring 79 functions
to push the pistons 54 and 60 apart from one another and
thereby reduces the pressure of the fluid in the cavity
68. As a consequence, a back-movement of the brake
cylinders 74 and 76 is supported.
Figure 4 shows a support element 80 for supporting a
structure according to a further embodiment of the
invention. Again, the support element 80 may function as
support element 12 or 14 in the embodiment shown in
Figures 1A and IB and described above. The support
element 80 comprises a cylinder 82 in which a piston 84 is
guided. The cylinder 82 has a fluid inlet/outlet opening
86 for receiving and ejecting fluid 88, such as a
hydraulic liquid or water. The piston 84 has seals 85 for
sealing the fluid in the cylinder 82. The fluid
inlet/outlet 86 is connected to another such fluid
inlet/outlet of another support element (not shown). In
this embodiment the support elemftnt RO comprises another
piston 90 positioned below the piston 84. The piston 84
has a cylindrical projection 92 which is positioned in a.
recess 96 of the piston 90.
The piston 90 has a ring-portion 98 which is composed
of an elastic material such as a rubber-like material and
the projection 92 of the piston 84 has a wedge portion
100. In this embodiment the piston 90 has a surface
contact portion 102 and when the support element 80 is in
an adjusted position after movement of the piston 84
relative to the cylinder 82, the surface contact portion
contacts the surface and the movement of the piston 90 is
restricted. The weight of the structure effects a further
movement of the piston 84 in a downward direction against
the piston 90 and the wedge portion 100 wedges the elastic
ring-like portion 98 outwardly against the interior wall
of the cylinder 82 and thereby inhibits further movement
of the pistons 90 and 84 in the cylinder 82.
Figure 5 shows a support element 110 for supporting a
structure according to a yet another embodiment of the
invention. Again, the support element 110 may function as
support element 12 or 14 in the embodiment shown in
Figures 1A and IB and described above. The support
element 110 comprises a cylinder 122 in which a piston 114
is guided. The cylinder 112 has a fluid inlet/outlet
opening (not shown) for receiving and ejecting fluid 118,
such as a hydraulic liquid or water. The piston 114 has a
seal 115 for sealing the fluid in the cylinder 112. The'
fluid inlet/outlet is connected to another such fluid
inlet/outlet of another support element (not shown). In
this embodiment the support element 110 comprises a
surface contact portion 120 which is positioned below the
piston 114 and around projection 122 of the piston 114.
The projection 122 has wedge-shaped side projections
124 and the surface contact portion 120 has wedge-shaped
recesses 126. In this embodiment, the surface contact
portion comprises two parts 120 a and 120 b. When the
support element 110 is in an adjusted potion after
movement of the piston 114 relative to the cylinder 112,
the surface contact portion 120 contacts the surface and
the movement of the surface contact portion therefore is
restricted. The weight of the structure effects a further
movement of the piston 114 in a downward direction against
the surface contact portion 120 and the wedge portions 122
move parts 120 A and 12 Ob apart from one another and
towards the interior wall of the cylinder 112. in this
embodiment, the lower part of the interior wall of the
cylinder 112 has at least one tooth 128 on the surface and
the parts 120 A and 120 B have toothed surfaces 130. When
the parts 120 A and 120 B are moved towards the interior
side wall of the cylinder 112, the teeth 128 engage with
the toothed surface 130 and the engagement inhibits
further movement of the piston 118 and the surface contact
portion 120.
Figures 6-7 show two support elements 140 and 140' in
use in a table 141. The support elements 140 and 140'
comprise a cylinder 132 and 132' in which a piston 134 and
134' is guided. The cylinders 132 and 132' have a fluid
inlet/outlet opening 136 and 136'. The fluid inlet/outlet
openings 136 and 136' are in fluid communication with one
another. In this embodiment the support elements 140 and
140' comprise a piston extension 144 and 144' which is
positioned below the pistons 134 and 134' and attached
thereto. The piston extensions 144 and 144' are guided in
telescopic cylinders 142 and 142'.
In use the table 141 is placed on an uneven surface
and the support elements 140 and 140' typically adjust for
the uneven surface. The fluid 138 will flow between the
cylinders 132 and 132' until the loading associated with
incorporated into a. table 161. The support elements 150
and 150' are in fluid communication by means of fluid
channel 163.
Figures 11-14 show a support element 170 for
supporting a structure in more detail. The support element
170 comprises a cylinder 172 in which a piston 174 is
guided. The cylinder 172 has a fluid inlet/outlet opening
176 for receiving and ejecting fluid 178, such as a
hydraulic liquid or water. The fluid 178 is contained in a
bladder 179. The fluid inlet/outlet 176 is connected to
another such fluid inlet/outlet of another support element
(not shown) . In this embodiment the piston 174 has a
cavity 180 having openings 182 and 184 at the side
portions of the piston 184. Cavity 180 contains fluid 181,
such as hydraulic fluid or water. In the openings 182 and
184 brake cylinders 186 and 188 are guided and if the
fluid pressure in the cylinder 172 is above a threshold
level/ the brake cylinders 186 and 188 are pushed against
the interior wall of the cylinder 172 so as to position
the piston 174 in a stationary position relative the
cylinder 172. The cavity 180 further includes seals 189
for retaining fluid 181 within the cavity 180. The
cylinder 172 also has a thread 173 for mounting on a
structure. In the embodiment shown in figure 14 the cavity
fluid 181 is maintained in a bladder 183.
Further, in the embodiment shown in figures 11-14 a
piston plate 194 is positioned between the fluid 178 in
the cylinder 172 and the piston 174. The piston plate 194
includes a piston plate guide 195 which extends into the
cavity 180. Seals 197 are positioned to retain fluid 181
in cavity 180
If the fluid pressure in the cylinder 172 is above a
threshold level the pressure is transferred through the
the structure acts to increase the fluid pressure within
the cylinders 132 and 132' above a threshold pressure and
the braking means 135 act to retain the piston 134 and
134' in a stationary position relative to the cylinder 132
and 132'. Consequently, the table 141 will then have a
stable position.
Figures 8, 9 and 10 show a support element ISO for
supporting a structure according to a yet another
embodiment of the invention. Again/ the support element
150 may function as support element 12 or 14 in the
embodiment shown in Figures 1A and IB and described above.
The support element 150 comprises a cylinder 152 in which
a piston 154 is guided. The piston 154 includes a seal 155
which stops the fluid 158 from escaping the cylinder 152.
The cylinder 152 has a fluid inlet/outlet opening 156. The
fluid inlet/outlet opening 156 is in fluid communication
with another such fluid inlet/outlet opening 156'. In this
embodiment the support element 150 comprises a piston
extension 160 which is positioned below, the piston 154 and
attached thereto. The piston extension 160 is guided in
telescopic cylinder 162. This piston extension 160 and
telescopic cylinder 162 combination protects the piston
154 and cylinder 152 assembly of support element 150. It
can be seen that in use the transverse load on the piston
154 and cylinder 152 assembly is limited by the protective
piston extension 160 and telescopic cylinder 162
combination.
In use the piston extension 160 and telescopic
cylinder 162 allow the support element 150 to be composed
of lighter-weight materials with less strength than would
be required without the piston extension 160 and
telescopic cylinder 162.
Figure 10 shows two support elements 150 and ISO1
fluid 181 in the cavity 180 into the brake cylinders 186
and 188 such that the brake cylinders 186 and 188 are
forced against the interior wall of the cylinder 172. At a
threshold level the piston 174 is held in a fixed position
in relation to the cylinder 172.
The distance between the brake cylinders 186 and 188
and the fluid 178 in the cylinder 172 is minimised in
order to reduce the overall length of the support element
170.
Figure 15 shows detail of a support element 200 for
supporting a structure in a further embodiment of the
invention. The support element 200 comprises a cylinder
202 in which a piston 204 is guided. The cylinder 202 has
a fluid inlet/outlet opening 206 for receiving and
ejecting fluid 208, such as a hydraulic liquid or water.
The fluid inlet/outlet 206 is connected to another such
fluid inlet/outlet of another support element {not shown).
The fluid inlet/outlet opening 206 includes a fluid
inlet/outlet extension 207 which extends through a fluid
chamber 209 of the cylinder 202.
In this embodiment the support element 200 has a
cavity 210 positioned between a piston plate 214 and
piston 204. The cavity 210 has an opening 211 extending
into the piston 204. Piston plate 214 abuts fluid chamber
209 and comprises a piston plate guide 216 which extends
into opening 211 in piston 204. Piston plate 214 further
comprises crimpers 218.
The fluid inlet/outlet extension 207 extends into the
cavity 210 and to the fluid inlet outlet 206 such that the
fluid enters the fluid chamber 209 after proceeding
through the cavity 210 within the fluid inlet/outlet
extension 207. Fluid inlet/outlet extension 207 includes a
flexible portion 208 which extends through the cavity 210.
The cavity 10 further includes a resistance means
212. Resistance means 212 retains the piston plate 214 in
a position distal from the piston 204. An increase in
fluid pressure within the fluid chamber 209 acts against
resistance means 212 to move the piston plate 214 proximal
to the piston 204. It can be seen that this movement
brings the crimpers 218 into contact with the flexible
portion 208. In use, this disrupts the flow of fluid
through fluid inlet/outlet extension 207 and inlet/outlet
206 into fluid chamber 209.
If the fluid pressure in the. cylinder 202 and fluid
chamber 209 is above a threshold level this disruption of
flow results in the braking of the piston 204 such that
the piston 204 is held in a fixed position in relation to
the cylinder 202.
Figures 16-18 show detail of a support element 220
for supporting a structure in a further embodiment of the
invention. The support element 220 comprises a cylinder
222 in which a piston 224 is guided. The cylinder 222 has
a fluid inlet/out let opening 226 for receiving and
ejecting fluid 228, such as a hydraulic liquid or water.
The fluid inlet/outlet 226 is connected to another such
fluid inlet/outlet of another support element (not shown).
The fluid inlet/outlet opening 226 includes a fluid
inlet/outlet extension 227 which extends through a fluid
chamber 229 of the cylinder 222.
In this embodiment the support element 220 has a
cavity 230 positioned between a piston plate 234 and
piston 224. Piston plate 234 abuts fluid chamber 229.
The fluid inlet/outlet extension 227 extends into the
cavity 230 and to the fluid inlet/outlet 226 such that the
fluid 228 enters the fluid chamber 229 after proceeding
through the cavity 220 within the fluid inlet/outlet
extension 227.
The fluid inlet/outlet extension 227 includes a
braking valve 236 which is tnoveable between a closed
position and an open position. In the open position fluid
228 flows through the fluid inlet/outlet extension 227 and
inlet/outlet 226. In the closed position fluid
inlet/outlet extension 227 is closed disrupting the flow
of fluid within the system.
The cavity 230 further includes a resistance means
232. Resistance means 232 retains the piston plate 234 in
a position distal from the piston 224. An increase in
fluid pressure within the fluid chamber 229 acts against
resistance means 232 to move the piston plate 234 proximal
to the piston 224. This movement actuates the valve 236 to
bring it into a closed position.
The closed valve 236 results in the braking of the
piston 224 such that the piston 224 is held in a fixed
position in relation to the cylinder 222.
In the embodiment of Figure 19 the piston plate 234
includes a piston plate guide 235 which extends into a
piston cavity 237 in the piston 224.
The braking valve 236 is a piston valve or ball
valve.
Figure 18 shows a detailed view of a ball valve 236
within support element 220. Ball valve 236 comprises valve
arm 238 which extends into cavity 230. When fluid pressure
in the cylinder 222 increases piston plate 234 moves
proximal to piston 224 actuating valve arm 238 to move. At
a threshold pressure ball valve 236 closes inlet/outlet
extension 227.
Figure 19 shows detail of a support element 240 for
supporting a structure in a further embodiment of the
invention. The support element 240 comprises a cylinder
242 in which a piston 244 is guided. The cylinder 242 has
a fluid inlet/outlet opening 246 for receiving and
ejecting fluid 248, such as a hydraulic liquid or water.
The fluid 248 is contained in a bladder 249. The fluid
inlet/outlet 246 is connected to another such fluid
inlet/outlet of another support element (not shown). The
fluid inlet/outlet opening 246 includes a fluid
inlet/outlet extension 247 which extends through the
bladder 249.
In this embodiment the support element 240 has a
cavity 250 positioned between a piston plate 254 and
piston 244. Piston plate 254 abuts bladder 249.
The fluid inlet/outlet extension 247 extends into the
cavity 250 and to. the fluid inlet/outlet 246 such that the
fluid 248 enters the bladder 249 after proceeding through
the cavity 250 within the fluid inlet/outlet extension
247.
The fluid inlet/outlet extension 247 includes a
braking member 256 which is moveable between a closed
position and an open position. In the open position fluid
248 flows through the fluid inlet/outlet extension 247 and .
inlet/outlet 246. In the closed position fluid
inlet/outlet extension 247 is closed disrupting the flow
of fluid 248 within the system. The breaking member 256
comprises a first ceramic disk 257 and a second ceramic
disk 258. The first ceramic disk 257 includes an aperture
259 which allows the flow of fluid 248 through
inlet/outlet extension 247.
The cavity 250 further includes a resistance bladder
252. Resistance bladder 252 is air or fluid-filled and
retains the piston plate 254 in a position distal from the
piston 244. An increase in fluid pressure within the fluid
chamber 249 acts against resistance means 252 to move the
piston plate 254 proximal to the piston 244. This movement
moves the second ceramic disk 258 such that it covers the
aperture 259 disrupting fluid flow through inlet/outlet '
extension 247. This results in the braking of the piston
244 such that the piston 244 is held in a fixed position
in relation to the cylinder 242.
Figure 20 shows a lever braking means 300 in a
support element. The support element 290 comprises a
cylinder 292 in which a piston 294 is guided. The cylinder
292 has a fluid inlet/out let opening 296 for receiving and
ejecting fluid 298, such as a hydraulic liquid or water.
The fluid 298 is contained in a bladder 299. The fluid
inlet/outlet 296 is connected to another such fluid
inlet/outlet of another support element (not shown).
The braking means 300 comprises a braking arm 306
which is attached to piston guide 305 and thereby
indirectly to piston plate 304. When the fluid pressure in
the cylinder 292 reaches a threshold value the piston
plate 304 moves downwardly actuating braking arm 306.
Braking arm 306 comes into contact with the internal wall
of cylinder 292. Contact between braking arm 306 and the
internal surface of cylinder 292 retains piston 294 in a
stationary position relative to cylinder 292.
The support can utilised in a variety of fields. For
example, the support system can support a building,
portable building, scaffolding, tripod, ladder, white
goods, tables, chairs, furniture, stands, viewing
platforms, machinery, bulldozers and construction
equipment.
Figure 21 shows a valve element 310 of a support
element for supporting a structure according to a yet
another embodiment of the invention. The valve element 310
is positioned between two support elements (not
illustrated). The valve element 310 comprises an upper
fluid reservoir 311 and a lower fluid reservoir 312. A
ceramic disk 313 is disposed between the upper reservoir
311 and lower reservoir 312. The valve element 310 further
comprises two opposing pistons, upper piston 315 and lower
piston 316. Upper piston 315 is positioned to be impacted
by a change in pressure in upper reservoir 311. Lower
piston 316 is positioned to be impacted by a change in
pressure in lower reservoir 312. The ceramic disk 313
includes an upper reservoir aperture 320 and a lower
reservoir aperture 321. The upper piston 315 includes an
upper piston aperture 322 while the lower piston includes
a lower piston aperture 323. The pistons 315 and 316 are
biased by means of springs 318 and 319 such that when the
pressure is below a threshold level in upper reservoir 311
the upper piston aperture 322 aligns with the upper
reservoir aperture 320 allowing fluid to flow
therethrough. Similarly when the pressure is below a
threshold level in lower reservoir 312 the lower piston
aperture 323 aligns with the lower reservoir aperture 321
allowing fluid to flow therethrough.
When the force of the fluid pressure on either piston
315 and 316 is below that of the biasing force of either
spring 318 and 319, the valve 310 is in an open position
and fluid can flow through the valve. The support is
arranged such that if a leg (not illustrated) rests upon a
surface such as the ground, the mass of the table
increases the pressure in the fluid in the reservoir
associated with that leg forcing the piston associated
with that leg to move to cover the associated aperture.
In Figure 21, if the fluid in one adjustable leg is
linked to the lower reservoir 312 and this leg is lifted,
so that it no longer takes load, the fluid pressure
between the lower piston 316 and the leg decreases. The
tension of the spring 319 is set so that a pressure
decrease will result in the lower piston 316 moving such
that the lower piston aperture aligns with the lower
reservoir aperture in the ceramic disk 313. This acts to
allow fluid transfer between each of the legs. If,
alternately, the leg associated with the upper reservoir
311 is lifted the fluid pressure between the upper piston
315 and the associated leg decreases, allowing the
upper piston 315 to move to open the upper reservoir
aperture 322.
Figure 22 shows a valve element 330 of a
support element for supporting a structure according to a
yet another embodiment of the invention. The valve element
330 is positioned between two support elements (not
illustrated). The valve element 330 comprises an upper
fluid reservoir 331 and a lower fluid reservoir 332. An
upper gel element 333 is associated with upper reservoir
331 while a lower gel element 334 is associated with the
lower reservoir 332. The gel elements 333 and 334 are
shaped such that a force imbalance is created between the
two sides of a gel element. Outside edges 335 and 336 of
the gel elements have a greater surface area than the
inner edges 337 and 338 have. If the pressure in upper
reservoir 331 increases/ the pressure on the outer edge
335 of upper gel element 333 produces a force imbalance
resulting in the gel element 333 deforming to decrease the
fluid flow between upper reservoir 331 and lower reservoir
332. The valve element 330 is adapted such that when both
the lower reservoir 332 and upper reservoir 331 are above
a certain pressure, the lower gel element 334 and upper
gel element 333 deform to abut one another, preventing
fluid flow between the lower reservoir 332 and the upper
reservoir 331. If either the lower reservoir 332 or upper
reservoir 331 loses pressure, the associated gel element
will spring back to allow fluid to flow between the upper
reservoir 331 and lower reservoir 332.
The valve element 330 is arranged such that the fluid
in one adjustable leg is linked to the lower reservoir 332
while the fluid in a second adjustable leg (not
illustrated)'is linked to the upper reservoir 331. Hence
if one leg is lifted/ so that it no longer takes load,
fluid transfer between each of the legs is allowed.
Figure 23 shows a valve element 340 of a support
element for supporting a structure according to a yet
another embodiment of the invention. The valve element 340
is positioned between two support elements {not
illustrated). The valve element 340 comprises an upper
reservoir 341 and a lower reservoir 342. An upper piston
343 is associated with upper reservoir 341 such that an
increase in pressure in upper reservoir 341 impacts upper
piston 343. Similarly, a lower piston 344 is associated
with upper reservoir 342 such that an increase in pressure
in lower reservoir 342 impacts lower piston 344. Each
piston 343 and 344 is disposed between an inner membrane
345 and 346 and an outer membrane 347 and 348. The upper
piston 343 and membranes 345 and 347 and lower piston 344
and membranes 346 and 348 are shaped such that an increase
in pressure in the corresponding reservoir impacts the
outer membrane 347 and 348 more than the inner membranes
345 and 346. A force imbalance is created between the two
sides of each piston. As a result, if the pressure in
upper reservoir 341 increases, the pressure on the outer
edge of upper piston 343 produces a force imbalance
resulting in the piston 343 moving inwards to decrease the
fluid flow between upper reservoir 341 and lower reservoir
342.
The valve element 340 is adapted such that when both
the lower reservoir 342 and upper reservoir 341 are above
a certain pressure, the inner membrane 346 of lower piston
344 and the inner membrane 345 of upper piston 343 abut
one another, preventing fluid flow between the lower
reservoir 342 and the upper reservoir 341. If either the
lower reservoir 342 or upper reservoir 341 loses pressure,
the associated piston will spring back to allow fluid to
flow between the upper reservoir 341 and lower reservoir
342.
The valve element 340 is arranged such that the fluid
in one adjustable leg is linked to the lower reservoir 342
while the fluid in a second adjustable leg (not
illustrated) is linked to the upper reservoir 341. Hence
if one leg is lifted, so that it no longer takes load,
fluid transfer between each of the legs is allowed.
Figure 24 shows a valve element 350 of a support
element for supporting a structure according to a yet
another embodiment of the invention. The valve element 350
is positioned between two support elements (not
illustrated). The valve element 350 comprises an upper
reservoir 351 and a lower reservoir 352. An upper piston
353 is associated with upper reservoir 351 such that an
increase in pressure in upper reservoir 351 impacts upper
piston 353. Similarly, a lower piston 354 is associated
with upper reservoir 352 such that an increase in pressure
in lower reservoir 352 impacts lower piston 354. Each
piston 353 and 354 is disposed on one side of a deformable
membrane tube 356 which allows fluid communication between
upper reservoir 351 and lower reservoir 352. The upper
piston 353 and lower piston 354 are shaped to have an
outer edge 357 and 358 which is broader than the piston's
inner edge 359 and 360. Hence an increase in pressure in
the corresponding reservoir impacts the outer edge 357 and
358 more than the inner edge 359 and 360. A force
imbalance is created between the two sides of each piston.
As a result, if the pressure in upper reservoir 351
increases, the pressure on the outer edge of upper piston
353 produces a force imbalance resulting in the piston 353
moving inwards to decrease the fluid flow through the
deformable membrane tube 356 between upper reservoir 351
and lower reservoir 352.
The valve element 350 is adapted such that when both
the lower reservoir 352 and upper reservoir 351 are above
a certain pressure, the deformable membrane tube prevents
fluid flow between the lower reservoir 352 and the upper
reservoir 351. If either the lower reservoir 352 or upper
reservoir 351 loses pressure, the associated piston will
spring back to allow fluid to flow between the upper
reservoir 351 and lower reservoir 352.
The valve element 350 is arranged such that the fluid
in one adjustable leg is linked to the lower reservoir 352
while the fluid in a second adjustable leg'(not
illustrated) is linked to the upper reservoir 351. Hence
if one leg is lifted, so that it no longer takes load,
fluid transfer between each of the legs is allowed.
Figures 25 and 26 show a valve element 370 of a
support element for supporting a structure according to a
yet another embodiment of the invention. In this
embodiment, each leg 371 - 374 being supported includes a
fluid bladder 375 and 375' When pressurised the fluid
bladders 375 take the load of the table leg. Each bladder
375 has two hose connections 376 and 377 allowing fluid
transfer between the fluid bladders 375. The hoses 376 and
377 extend between the fluid bladders 375 such that for
any given fluid bladder, one hose connection is controlled
by a valve 378 and the other hose connection is open to
the bladder.
In the case of a support with two bladders 375 the
hoses 376 and 377 are connected in cross over
style as shown in Figure 5. That is, the hose 377 on one
leg, connected via the valve 378, is connected directly to
the bladder on the other leg without a valve, and vice
versa. With this connection arrangement, when both valves
are closed, no fluid transfer occurs, and when either
valve is open fluid transfer can occur.
In a four bladder arrangement each bladder is
connected to its two closest neighbours. Figure 6 shows
the connections between the legs. Each leg is connected to
two other legs, but not to the diagonally opposite leg.
Thus if the leg 372 is not on the ground taking load, it
can draw fluid from the two neighbouring connected legs,
but not the diagonally opposite leg. Further, if more than
one leg is lifted from the ground, all lifted legs can
receive fluid from the legs taking load.
The valve 378 is a tube pinch valve which acts to
block fluid transfer tube when weight is placed on the
table leg. If all feet are touching the ground, each
bladder is pressurised and can support weight from the
table. As a result the table weight acts to pinch the
transfer tubes closed so that no fluid flow can occur.
If a foot is lifted from the ground, that unit no longer
takes any weight from the table and the pressure from the
other connected bladders will force the valve 378 to move
away from the upper tube and allow fluid flow through the
upper tube, thus extending the leg until it touches
the ground and starts to take some of the table weight.
Figures 27 and 28 show a support element incorporated
into a helicopter landing structure 380. The helicopter
landing structure 380 comprises two or more independent
landing struts 382. Each landing strut 382 incorporates
one or more support elements 400. In the case where one
landing strut 382 incorporates more than one support
element 400, the landing strut may be divided such that in
use there are four or more independent landing elements.
The support element 400 comprises a cylinder 402 in
which a piston 404 is guided. The piston 404 is attached
to the helicopter landing strut 382 such that movement of
the landing structure 382 correlates with movement of the
piston 404. The cylinder 402 has a fluid inlet/outlet
opening 406 for receiving and ejecting fluid 408, such as
a hydraulic liquid or water. The fluid 408 is contained in
a bladder 409. The fluid inlet/outlet 406 is connected to
another such fluid inlet/outlet of another support element
(not shown).
The support element 400 further comprises braking
means 384.
In use, upon the helicopter (not illustrated) landing
on an uneven surface, the support element 400 typically
adjusts for the surface and fluid 408 will flow between
the cylinder 402 and the cylinder of another support
element (not shown) associated with a separate landing
strut (not shown). The fluid 408 will flow until the
loading associated with the structure acts to increase the
fluid pressure within the cylinder 402 above a threshold
pressure and the braking means 384 act to retain the
piston 404 in a stationary position relative to the
cylinder 402. Consequently, the helicopter landing
structure 380 will then have a stable position. This
increases the safety of helicopter landings.
The support shown in Figures 1A and IB can also be
used for a level adjustment for furniture or white goods.
For example, the structure 16 may be a refrigerator
supported by four support elements such as support element
12 and 14. If the refrigerator is tilted backwards, the
pistons of the rear support elements move upwards and push
hydraulic liquid into the cylinders of the front support
elements and the pistons of the front support elements
move in a downward direction. Once the refrigerator is
released, the refrigerator will stay in the adjusted
position and the weight of the refrigerator will cause the
brakes of each support element to engage the respective
piston with the respective cylinder.
The cylinder and pistons may be composed of a
metallic material such as aluminium or steel.
Alternatively, the pistons and cylinders may also be
composed of a suitable plastics material. The
inlet/outlets of the support elements typically are
interconnected using a suitable rubber hose, but may also
be interconnected using a plastics or metallic hose.
The internal diameter of the hose and also additional
valves may be used to control the throughput of the
hydraulic liquid through the hose and therefore the
sensitivity (reaction speed) of the support for adjusting
for changed loading conditions. The inlet /out lets may also
be interconnected via a reservoir.
Although the invention has been described with
reference to particular examples, it will be appreciated
by those skilled in the art that the invention may be
embodied in many other forms. For example, the cylinder of
each support element may comprise braking means that has
parts which move against a side portion of the piston.
Further, the cylinder of each support element may comprise
a surface contact portion and the piston may be arranged
to be connected to the•structure. In addition, it is to be
appreciated that the pistons and cylinders may be composed
of any suitable material and may be of any suitable shape.
Further, the support may only comprise one support
element. For example, the support may be a single
supporting member, such as a prop for supporting a
building structure, which is compressible and has a
braking means which engage above a predetermined loading
so that the supporting member can support the structure.
In the claims which follow and in the preceding
description of the invention, except where the context
requires otherwise due to express language or necessary
implication, the word "comprise or variations such as
'comprises or comprising is used in an inclusive seni
i.e. to specify the presence of the stated features but
not to preclude the presence or addition of further
features in various embodiments of the invention.
THE CIAIMS;
1. A support for supporting a structure on a surface,
the support comprising at least one support element, the
or each support element comprising:
a piston,
a cylinder in which the piston is moveable, and
a braking means for maintaining the piston in a
position that is stable relative to the cylinder,
wherein the piston and the cylinder are arranged so
that a loading associated with the structure effects an
adjustment of the support element,
and wherein an increase in hydraulic pressure within
the cylinder, effected by the loading associated with the
structure, activates the braking means.
2. A support as claimed in claim 1 wherein the cylinder
has a fluid inlet/outlet and is arranged so that an amount,
of fluid flowing through the or each inlet/outlet controls
20 the movement of the or each piston relative to the or each
cylinder.
3. A support as claimed in claim 2 wherein the movement
of the or each piston effects a movement of a surface
contact portion of the or each support element relative to
the surface.
4. A support as claimed in claim 3 comprising at least
two support elements, each of the support elements having
a surface contact portion and wherein the fluid
inlet/outlets are interconnected by at least one fluid
conduit so that the fluid can flow between the
inlet/outlets.
5. A support as claimed in claim 4 being arranged so
that in use, when the support is placed on the surface and
at least one of the surface contact portions does not
contact the surface, a movement of the pistons relative to
the cylinders is effected that adjusts the positions of
the surface contact portions relative to the surface.
6. A support as claimed in claim 5 wherein each piston
comprises the surface contact portion arranged to contact
the surface.
7. A support as claimed in claim 5 wherein the surface
contact portion is a component that is either in direct or
indirect contact with the piston.
8. A support as claimed in any one of claims 5 to 7
i
being arranged so that the pistons move relative to the
cylinders, until an increase of fluid pressure in the
cylinders actuates the braking means.
9. A support as claimed in any one of claims 5 to 8
wherein the braking means of each support element is
hydraulic.
10. A support of claim 9 wherein the piston of each
support element has a cavity arranged so that in use fluid
can penetrate from the inlet/outlet into the cylinder and
into the cavity.
11. A support as claimed in claim 10 wherein the piston
of each support element is elongate and at least one side
portion has at least one recess that is linked to the
cavity.
12. A support as claimed in claim 11 wherein a brake-pad
or brake-cylinder is positioned in the or each recess of
the piston and arranged so that if fluid penetrates into
the cavity the or each brake-pad or brake-cylinder is in
use moved towards an interior wall of the cylinder.
13. A support as claimed in claim 12 wherein the braking
means is arranged so that an increase of the fluid
pressure in the cavity increases the pressure of the or
each brake-pad or brake-cylinder against the interior wall
of the cylinder and thereby acts against the moveability
of the piston in the cylinder.
14. A support as claimed in claim 9 wherein the cylinder
has at least one recess in an interior side wall and at
least one brake pad or brake cylinder is positioned in the
or each recess of the interior side wall and arranged to
push against the piston to act against the moveability of
the piston in the cylinder.
15. A support as claimed in any one of claims 5 to 8
wherein the braking means of each support element-is
mechanical.
16. A support as claimed in claim 15 comprising a brake
portion which is moveable relative to the cylinder and
with the piston until the movement of the surface contact
portion is restricted.
17. A support as claimed in claim 16 wherein the brake
portion is arranged so that, when the movement of the
brake portion is restricted, a further movement of the
piston relative to the cylinder activates the braking
means.
18. A support of claim 17 wherein the braking means has
wedging portions which in use effect a movement'of the
brake portion against an interior wall of the cylinder.
19. A support as claimed in any one of the preceding
claims having three support elements.
20. A support as claimed in any one of claims 1 to 18
having four support elements.
21. A support as claimed in any one of the preceding
claims wherein the structure is a furniture item.
22. A support as claimed in any one of the preceding
claims wherein the structure is a table.
23. A support as claimed in any one of claims 1 through
8, wherein the braking means is situated between two or
more support elements and comprises at least two fluid
reservoirs adapted such that when the pressure in at least
one fluid reservoir is below a threshold level the fluid
reservoirs are in fluid communication and when the
pressure in at least two fluid reservoirs is above a
threshold level the fluid reservoirs are not in fluid
communication.
24. A support as claimed in claim 23 further comprising
valve disposed between the fluid reservoirs.
25. A support as claimed in claim 24, wherein the valve
comprises:
a ceramic disk disposed between the reservoirs, the
ceramic disk including at least one reservoir aperture;
at least two pistons/ each piston being associated
with a reservoir, each piston including a piston aperture,
each piston being biased such that when the pressure in
any reservoir is below a threshold level the piston
aperture aligns with the reservoir aperture allowing fluid
to flow therethrough and when the pressure in all
reservoirs is above a threshold level the piston.
26. A support as claimed in claim 24, wherein the valve
comprises:
at least two sealing elements, each sealing element
being associated with a reservoir, wherein the sealing
elements are shaped such that a change in pressure results
in relative movement of the sealing elements with respect
to one another such that if the pressure in all reservoirs
is above a threshold level the sealing elements abut,
preventing fluid flow between the reservoirs.
27. A support as claimed in claim 26, wherein the sealing
elements are composed of gel.
28. A support as claimed in claim 27, wherein the sealing
elements are pistons.
29. A support as claimed in claim 28 wherein the pistons
are disposed between membranes.
30. An adjustable support for supporting a structure on
an underlying surface, the support comprising a piston
cylinder assembly, the piston being moveable relative to
the cylinder with one of the piston or cylinder being
connected to, or forming part of, the structure and the
other being associated with a contact portion operative to
engage the underlying surface, and braking means for
inhibiting movement of the piston relative to the
cylinder, wherein the braking means is operative in
response to the application of predetermined loading
conditions to a portion of the support.
31. An adjustable support according to claim 30 wherein
the braking means is operative in response to a threshold
loading being applied to that portion of the piston
cylinder assembly that is associated with the contact
portion.
32. A braking system for a piston and cylinder assembly,
the braking system comprising a braking means adapted to
be actuated by an increase in fluid pressure within the
cylinder.
33. A braking system as defined in claim 32, wherein the
piston has a cavity arranged so that in use fluid can
penetrate from an inlet/outlet into the cylinder and into
the cavity and wherein at least one side portion of the
piston has at least one recess that is linked to the
cavity.
34. A braking system as defined in claim 33, wherein a
brake-pad or brake-cylinder is positioned in the or each
recess of the piston and arranged so that if fluid
penetrates into the cavity the or each brake-pad or brakecylinder
is in use moved towards an interior wall of the
cylinder.
35. A braking system as defined in claim 34 , wherein the
braking means is arranged so that an increase of the
fluid pressure in the cavity increases the pressure of
the or each brake-pad or brake-cylinder against the
interior wall of the cylinder and thereby acts against
the moveability of the piston in the cylinder.
36. A braking system as defined in claim 32, further
including a fluid chamber within the cylinder, a piston
plate positioned between the piston and the fluid
chamber, and a cavity between the piston and the piston
plate, the cavity containing:
resistance means such that in use the piston and
piston plate are retained in a distal position relative to
one another and on an increase in fluid pressure within
the fluid chamber the piston and piston plate move
proximal to one another;
at least one inlet/outlet extension extending through
at least a portion of the cavity so that in use fluid can
flow through the inlet /out let extension and into the
cylinder;
means for disrupting the flow of fluid through the
inlet/outlet extension and into the cylinder upon an
increase in fluid pressure within the cylinder.
37. A braking system as defined in claim 36, wherein the
resistance means comprises a spring.
38. A braking system as defined in claim 36, wherein the
resistance means comprises a fluid-filled bladder.
39. A braking system as defined in any one of claims 36
to 38, wherein the inlet/outlet extension comprises a tube
extending through the cavity and into the cylinder.
40. A braking system as defined in claim 39, wherein the
tube is flexible and at least one of the piston plate and
piston comprises crimpers extending into the cavity such
that when the fluid pressure in the cylinder increases and
the piston plate, and piston move proximal to one another
the crimpers compress the flexible tube and disrupt fluid
flow into the cylinder.
41. A braking system as defined in claim 39, wherein the
tube includes a valve such that when the fluid pressure in
the cylinder increases and the piston plate and piston
move proximal to one another the valve disrupts fluid flow
through the tube and into the cylinder.
42. A braking system as defined in claim 41, wherein the
valve is a ball valve.
43. A braking system as defined in claim 39, wherein the
tube includes a first member extending therethrough and
the cavity contains a second member, the first member
including a flow aperture to allow fluid penetration
through the tube, the second member being adapted to move
between an open position and a closed position such that
in the closed position the flow aperture is blocked by the
second member, disrupting fluid penetration through the
tube and into the cylinder.
44. A braking system as defined in claim 43, wherein the
first member and second member are each ceramic disks.
45. A braking system as defined in any of claims 36 to
44, wherein the inlet/outlet extension comprises a helical
flexible tube portion extending through at least a portion
of the cylinder.
46. A support for supporting a structure on a surface,
the support comprising at least one support element, the
or each support element comprising:
a piston,
a cylinder in which the piston is moveable, and
a braking means for maintaining the piston in a
position that is stable relative to the cylinder,
wherein the piston and the cylinder are arranged so
that a loading associated with the structure effects an
adjustment of the support element,
and wherein the loading associated with the structure
activates the braking means if the moveability of a
I
surface contact portion of the support element is reduced
below a threshold value.
