Specification
A BEARING FOR A PULLER SYSTEM OF A WEAVING LOOM, AND A
PULLER SYSTEM INCLUDING SUCH A BEARING
The present invention relates to a bearing for fitting to a puller system
of a weaving loom. The present invention also relates to a puller system
including such a bearing.
A shed forming device of a weaving loom generally includes a plurality
of heddle frames that are actuated individually by a puller system. For each
heddle frame, the puller system comprises a set of link rods and levers. The
sets of a puller system are mounted in parallel in a small space.
The elements of the puller system are hinged to one another via pivotal
connections made by means of ball bearings or roller bearings. For a given
size, roller bearings have greater load capacity than ball bearings. In a puller
system, the bearings present limited axial size, with the most usual value
being less than 10 millimeters (mm). Assembling, mounting, removing, and
maintaining these bearings are all made complicated by this limited axial size,
since the elements that constitute the bearings need to be relatively compact.
EP-A-0 437 896 describes a bearing comprising an inner ring and an
outer ring having rollers between them in a radial direction, and also having
two end plates or bearing shields for holding the rollers in an axial direction.
The bearing shields are disposed respectively on either side of the rollers.
The bearing shields are secured to the inner ring by two slightly frustoconical
rims that are made on the outer radial surface of the inner ring, facing towards
the rollers. The two rims co-operate with respective complementary surfaces
of each of the bearing shields.
However, in order to ensure that the assembled bearing can withstand
axial forces, the bearing shields need to be assembled as a tight fit on the
inner ring. Such assembly requires the bearing shields to be expanded by
being heated, which is relatively awkward and difficult. In addition, fitting the
bearing shields on the inner ring requires very high precision in the
preparation of the complementary frustoconical surfaces of the bearing
shields and of the inner ring. Furthermore, in order to maintain the cohesion
of the assembled bearing in spite of axial forces, it is necessary to have
complementary frustoconical surfaces of relatively large extent in an axial
direction, thereby significantly increasing the axial size of the bearing. Under
such circumstances, the width of the rollers is reduced to the detriment of the
load capacity.
An alternative bearing that is more compact has two flat bearing
shields fastened in two respective radial grooves formed in an outer surface of
the inner ring facing towards the rollers. Each bearing shield is then
assembled on the inner ring by being deformed elastically. Nevertheless,
assembling such a bearing still requires great precision in the machining of
the bearing shields and of the radial grooves. In addition, if the diameter at
the bottom of a radial groove is greater than the inside diameter of the bearing
shield mounted therein, then the bearing shield deforms and becomes
unstable, and runs the risk of moving away from its nominal position.
The present invention seeks specifically to remedy those drawbacks,
by proposing a puller bearing that presents high load capacity, that is very
compact, that withstands axial forces well, and that is relatively easy and fast
to assemble.
To this end, the invention provides a bearing for a puller system of a
weaving loom, the bearing comprising:
rollers of substantially cylindrical shape;
an inner ring and an outer ring extending respectively on either side of
the rollers with respect to a radial direction, the inner ring and the outer ring
defining respective inner and outer cylindrical raceways, the inner ring
comprising two lateral surfaces extending radially and disposed with respect
to an axial direction on either side of the inner raceway, and two inner lateral
surfaces each presenting a generally frustoconical shape and diverging on
going away from a central axis of the bearing; and
• two bearing shields disposed respectively on either side of the inner
raceway in the axial direction and designed to be placed between two lateral
flanges belonging to the puller system;
the bearing being characterized in that each bearing shield comprises:
. a first portion extending radially over all or part of the corresponding
lateral surface; and
. a second portion adapted to cover a substantial portion of the
corresponding inner lateral surface.
In other words, each end plate or bearing shield is compressed
between a lateral flange and one of the inner lateral surfaces of the inner ring,
thereby holding it stationary relative to the inner ring, in particular in rotation,
and thus conferring to the bearing a good ability to withstand axial forces.
Since the bearing shields are secured to the inner ring via the inner lateral
surfaces, no extra axial space is required for this purpose.
According to other features of the invention that are advantageous but
optional, taken in isolation or in any technically feasible combination:
. each bearing shield comprises holder members, and the inner ring
comprises receiving means for receiving the holder members, the receiving
means being adapted to co-operate with the holder members so as to hold
each bearing shield on the inner ring;
. the holder members comprise at least one elastically deformable tab
that locally extends the second portion and that presents an end that is curved
towards the inner ring so as to hold each bearing shield to the inner ring;
. the receiver means are formed by at least one rim formed on the inner
ring and between the two inner lateral surfaces;
. the inner ring presents at least one cavity adapted to receive at least
one tab, the rim being formed by projecting portions lying between respective
cavities in the respective inner lateral surface;
. the cavities are formed by a single groove that is formed between the
two inner lateral surfaces and that is annular in shape and symmetrical about
the bisector plane of the bearing;
. the rim is formed projecting on a cylindrical surface between the two
inner lateral surfaces;
. the respective dimensions of each second portion and of the
corresponding inner ring are determined so as to leave, after assembly of the
bearing, axial clearance between each second portion and the corresponding
inner ring;
. each second portion is formed by a collar that extends the
corresponding first portion that is in the form of a substantially flat annulus that
extends radially facing the corresponding lateral surface;
. each second portion is formed by a plurality of sectors that are
separated in pairs by notches, each sector extending substantially along a
direction that has a radial component and an axial component;
. the notches extend into the annulus;
. the number of notches lies in the range 4 to 10; and
. the frustoconical surfaces of each inner lateral surface and of each
second portion present a half-angle at the apex lying in the range 20° to 60°.
The invention also provides a puller system for a weaving loom
including at least one link rod and at least one lever, the puller system being
characterized in that the link rod and the lever are connected together by
means of a bearing as described above, the lateral flanges being constituted
by the link rod and being secured to the inner ring by means of a conical bolt
and nut fastener tightened against the lateral flanges.
The invention can be well understood and its advantages appear
clearly in the light of the following description given purely by way of non-
limiting example and made with reference to the accompanying drawings, in
which:
. Figure 1 is a front view of a portion of a puller system in accordance
with the invention and comprising bearings in accordance with the invention;
. Figure 2 is a fragmentary section on a larger scale on line ll-ll of
Figure 1, showing a bearing in accordance with the invention;
. Figure 3 is a perspective view of a bearing shield forming part of the
Figure 2 bearing;
. Figure 4 is a view looking along arrow IV of Figure 3;
. Figure 5 is a section on line V-V of Figure 4, showing the bearing
shield of Figure 3;
. Figure 6 is a view on a larger scale showing a detail VI of Figure 2;
. Figure 7 is a view analogous to Figure 6 showing an intermediate
state during assembly of the Figure 2 bearing; and
. Figure 8 is a view analogous to Figure 7 showing an intermediate
state during assembly of a variant of the Figure 2 bearing.
Figure 1 shows a shed-forming device comprising a plurality of heddle
frames or heald frames, one of which is shown in Figure 1 under the
reference C. In known manner, the frame C is fitted with heddles (not shown)
each having an eyelet passing a warp yarn represented by arrow F1 that
shows its travel direction along an axis perpendicular to the plane of the frame
C and of Figure 1.
Each frame of type C is driven with in vertical oscillatory motion as
represented by double-headed arrow F2- This oscillatory motion is
transmitted in particular by means of a distal link rod 20 coupled to the bottom
portion of the frame C and by a lever 22. The lever 22 is connected to a drive
arm 28 via a proximal link rod 24 and a fastener 26 for adjusting the shed, the
drive arm 28 itself being set into motion by a dobby 1. The puller system 2
also includes a link rod 21 shown in part in Figure 1 and serving to transmit
the oscillatory motion of the lever 2 to the end of the frame C that is not
shown, via another lever and another distal link rod 20.
The pivoting connections of the proximal link rod 24 with the fastener
26 at one end, and with the lever 22 at the other end, are provided by means
of roller bearings that are described in greater detail with reference to
Figures 2 to 8. The outer rings of the roller bearings are designed to be
engaged in a bore 25 of the fastener 26 or in a bore 23 of the lever 22. The
inner rings of the bearings are secured to the link rod by means of conical
screws 27A or 29A and conical nuts 29B that are tightened together in the
central portions of the bearings.
Figure 2 shows a bearing 30 of the type commonly referred to as a
biconical bearing that provides the pivoting connection between the link rod
24 and the fastener 26. In the field of textile machinery, a biconical bearing is
a bearing in which the inner ring is clamped between two flanges by means of
a bolt situated in its center. The ring has two symmetrical surfaces in its bore
that are open to the outside of the bearing, of generally conical shape, and
designed to co-operate with corresponding surfaces of the flanges. The
rolling components of the bearing 30 are adapted to rotate about an axis of
symmetry X30 of revolution of the bearing 30. The axis X30 forms a central
axis of rotation for the bearing 30. The components of the bearing 30 are
guided and held axially by means of two lateral flanges 24A and 24B, here
constituted by end legs of the link rod 24.
As shown in Figure 2, the bearing 30 comprises an inner ring 32 and
an outer ring 36 between which rollers 34 are received to roll. The inner ring
32 occupies a space that is defined in a radial direction, as represented by an
axis Y, by an inner raceway 321 for the rollers 34. The outer ring 36 extends
along the radial direction Y away from the space defined by an outer raceway
361 for the rollers 34. In the context of the present invention, the adjectives
"inner" and "outer" designate entities that are respectively closer to and further
from the axis X30 in the radial direction Y. For the purpose of maintaining the
bearing 30, the outer ring 36 includes a radial hole 360 that opens out firstly
into the housing for the rollers 34, and secondly into a greasing hole 260
formed in the fastener 26, the latter here constituting a male portion for
assembling the bearing 30.
The inner and outer raceways 321 and 361 are thus defined
respectively by the inner ring 32 and by the outer ring 36. The inner and outer
raceways 321 and 361 enclose the paths followed by the rollers 34, which are
here in the form of right cylinders. The term "cylinder" is used to designate a
cylinder of circular base, since the rollers 34 are bodies of revolution about
their respective axes X34.
The rollers 34 present flanks 342 and 343 in the form of disks that are
perpendicular to an axial direction X and parallel to the axis X30. The bearing
shields 40 and 50 of the bearing 30 and the inner and outer rings 32 and 36
together define the housing for the rollers 34. A cage made up of two annular
sectors 37 and 38 with spacers between the rollers 34 is disposed
respectively between the bearing shields 40 and 50. The cage holds the
rollers 34 in their housing and in contact with the inner and outer raceways
321 and 361. It is nevertheless possible to make a bearing that does not
include a cage and in which the rollers come directly into contact with the
bearing shields.
The outer radial surface of the inner ring 32 defines the inner raceway
321. Beside the axis X30, the inner ring 32 has two inner lateral surfaces 324
and 325. The inner ring 32 also has two lateral surfaces 322 and 323 that are
plane and perpendicular to the axial direction X and that are disposed in the
axial direction X on either side of the inner raceway 321. The lateral surfaces
322 and 323 extend radially and respectively between the inner raceway 321
and each of the inner lateral surfaces 324 and 325.
Each of the inner lateral surfaces 324 and 325 is generally
frustoconical in shape, diverging on going away from the axis X30, i.e. on
going towards the corresponding lateral surface 322 or 323 of the inner ring
32. Specifically, the inner ring 32 presents symmetry about its bisector plane
represented in Figure 2 by the axis Y30. Thus, the lateral surfaces 322 and
323 and the inner lateral surfaces 324 and 325 are respectively symmetrical
relative to the bisector plane. The inner lateral surfaces 324 and 325 diverge
from the bisector plane as far as the corresponding lateral surface 322 or 323.
The bearing 30 has two end plates or bearing shields 40 and 50 that
are disposed respectively on either side of the rollers 34 in the axial direction
X. The function of the bearing shields 40 and 50 is specifically to guide and
retain the rollers 34 axially via the cage that holds them. The bearing shields
40 and 50 are adapted to take up the axial forces that may be exerted by the
rollers 34.
As shown in Figures 2 to 5, each bearing shield 40 or 50 comprises a
generally flat and relatively fine annulus 41 or 51 with an inner diameter
referenced D41. Each bearing shield 40 or 50 also comprises a second
portion formed by a respective collar 42 or 52 that extends the corresponding
annulus 41 or 51 at inner diameter D41 and that defines a central opening 45
of diameter D45 that is less than the diameter D41. After the bearing 30 has
been assembled, the annuluses 41 and 51 occupy radially outer positions,
while the collars 42 and 52 occupy radially inner positions.
After the bearing 30 has been assembled, each bearing shield 40 or 50
covers the inner ring 32 laterally together with the rollers 34 and all or part of
the outer ring 36. More precisely, the annulus 41 extends radially over the
lateral surface 322, the annular sector 37 of the cage adjacent to the flanks
342, and a lateral surface 362 of the outer ring 36. Similarly, the annulus 51
extends radially over the lateral surface 323, the annular sector of the cage
adjacent to the flanks 343, and a lateral surface 363 of the outer ring 36.
Each annulus 41 or 51 is adjacent to the rollers 34 over their entire radial
extent, since they cover laterally both the inner ring 32 and a substantial
portion of the outer ring 36.
In addition, the collar 42 of the bearing shield 40 is adapted to cover a
substantial portion of the inner lateral surface 324. Similarly, the collar 52 of
the bearing shield 50 is adapted to cover a substantial portion of the inner
lateral surface 325. The term "adapted" indicates that each collar 42 or 52
presents a shape similar to that of the corresponding inner lateral surface 324
or 325. The collar 42 is thus generally frustoconical in shape corresponding
to the shape of the inner lateral surface 324. Similarly, the collar 52 is
generally frustoconical in shape corresponding to the shape of the inner
lateral surface 325.
As shown in Figures 3 to 5, the collar 42 is made up of eight annular
sectors, referenced 421 to 428, that are spaced apart in pairs by eight
respective notches 431 to 438. In other words, virtually uniting the eight
sectors 421 to 428 represents a frustoconical annular surface that constitutes
the collar 42. In practice, the number of these sectors and these notches may
lie in the range four to ten. In a variant that is not shown, each second portion
may be continuous around the central axis of the bearing, i.e. it need not have
any notches.
Each of the notches 431 to 438 extends substantially in a direction that
has a radial component and an axial component along the axis X. Each of the
notches 431 to 438 begins in the center of the bearing shield 40, in its central
opening 45, and then "crosses" the collar 42 to terminate in a radial portion
within the annulus 41. Within the annulus 41, each of the notches 431 to 438
is terminated by a circular opening that serves to spread stresses and thus
avoid weakening the bearing shield 40.
The notches 431 to 438 impart good flexibility to each of the eight
sectors 421 to 428 making up the collar 42 since they enable each of the
sectors 421 to 428 to deform elastically in independent manner relative to the
annulus 41. The fact that each of the sectors 421 to 428 is flexible makes the
collar 42 better adapted to cover the inner lateral surface 324, thereby
facilitating assembly of the bearing 30. This also makes it easier to mount the
bearing 30 in the puller system 1, and in particular to secure its inner ring 32
with the flanges 24A and 24B of the link rods. As mentioned above, the collar
42 or 52 is adapted to cover a substantial portion of the corresponding inner
lateral surface 324 or 325. The collar 42 or 52 covers the corresponding inner
lateral surface 324 or 325, with the exception of those regions of the inner
lateral surface 324 that are left uncovered by the notches 431 to 438.
The bearing shield 40 may be made by stamping and cutting
operations so as to form the annulus 41 and the collar 42, i.e. the sectors 421
and 428 and the notches 431 to 438. It is preferable to make the bearing
shield 40 out of a hard material that withstands wear and the static and/or
dynamic stresses that act on the bearing 30. By way of example, the bearing
shield 40 may be made of high-strength steel sheet.
Furthermore, the bearing shield 40 has two tabs 441 and 445
extending the collar 42 from diametrically opposite positions relative to the
central opening 45. The tabs 441 and 445 are integral with the sectors 421
and 425 to which they are joined by respective folds 4421 and 4425. The
tabs 441 and 445 and the sectors 421 and 425 come from a single piece that
is initially in the form of a flat annulus and that is subsequently cut and
stamped. In the initial state of this part, the tabs 441 and 445 extend the
sectors 421 and 425 respectively in the plane of the annulus 41. Each tab
441 and 445 thus forms a lug that is folded towards the annulus 41, i.e.
towards the inner ring 32 once the bearing 30 has been assembled, at an
angle of inclination opposite from that of the collar 42. The tabs 441 and 445
serve in particular to hold the bearing shield 40 on the inner ring 32, as
described below with reference to Figures 6 to 8.
The above description of the bearing shield 40 can be transposed
directly to the bearing shield 50 insofar as the bearing shields 40 and 50 are
here of identical structure and are arranged on either side of the bisector
plane of the bearing 30, as represented by the axis Y30 in Figure 2. The
numerical references of the elements of the bearing shield 50 are obtained by
replacing the prefix digit 4 with the prefix digit 5 in the numerical references for
the corresponding elements of the bearing shield 40. Thus, there is the
annulus 51, the collar 52, the tab 541, etc.
Likewise, the description of the bearing shield 50 given with reference
to Figures 6 and 7 can be transposed directly to the bearing shield 40. The
numerical references of the elements of the bearing shield 40 are then
obtained by replacing the prefix digit 5 with the prefix digit 4 in the numerical
references for the corresponding elements of the bearing shield 50.
When the bearing 30 is in the assembled state in the puller system 1,
as shown in Figures 2 to 6, the tightening of the conical screw 29A in the
conical nut 29B presses the flanges 24A and 24B respectively against the
bearing shields 40 and 50. The bearing shields 40 and 50 are thus pressed
against the inner ring 32 and, in particular, against the inner lateral surfaces
324 and 325. More precisely, the frustoconical head of the nut 29B
compresses the frustoconical portion 242 of the flange 24B, which in turn
compresses the collar 52 against the inner lateral surface 325.
In the plane of Figure 6, which is a meridian plane of the bearing 30,
the collar 52 and the inner lateral surface 325 extend in an oblique direction L.
The direction L forms an angle a with the axial direction X, where a is equal to
about 30°. Since the collar 52 and the inner lateral surface 325 are
frustoconical, the angle a represents the half-angle at the apex of the collar 52
and of the inner lateral surface 325. In practice, the angle a may lie in the
range 20° to 60°.
As shown in Figure 7, the cylindrical surface between the two inner
lateral surfaces 324 and 325 of the inner ring 32 presents a groove 326 of
annular shape that is symmetrical about the bisector plane of the inner ring
32. The groove 326 defines two annular rims 327 and 329 that form
projecting portions between the bottom of the groove 326 and the
corresponding inner lateral surface 324 or 325.
During assembly of the bearing 30, the inner and outer rings 32 and 36
are disposed on either side of the rollers 34 which are grouped together by
the cage, and then the bearing shields 40 and 50 are pressed against the
inner ring 32. The two tabs of the bearing shield 50, only one of which, 541, is
shown in Figure 7, come into contact with the inner lateral surface 325 and
become deformed progressively until they penetrate into the groove 326. As
shown in Figure 7, the tab 541 is in contact with the rim 327 and holds the
bearing shield 50 assembled on the inner ring 32. Clip fastening thus occurs,
while nevertheless leaving a certain amount of axial clearance to the bearing
shield 50 that is compatible with the need for the assembled bearing to hold
together on its own.
In analogous manner, the tabs 441 and 445 of the bearing shield 40
come into contact with the inner lateral surface 324 and deform progressively
until they penetrate into the groove 326. The bearing shield 40 is then held
associated with the inner ring 32. The tabs 441, 445, 541, and equivalent
constitute a corresponding number of members for holding the respective
bearing shields 40 or 50 on the inner ring 32 and the rims 327 and 329
constitute means for receiving the tabs 441, 445, and 541.
The above description of the tab 541 and the way it co-operates with
the inner ring 32 can be transposed directly to the tabs 441 and 445 of the
bearing shield 40 and also to the other tab of the bearing shield 50 that is
symmetrical relative to the tab 541, but that is not shown. Nevertheless, the
tabs 441 and 445 co-operate with the rim 329 against which they are wedged
and that is symmetrical relative to the rim 327 about the bisector plane Y30,
while the tab 541 and its equivalent co-operate with the rim 327.
In the bearing 30, the tabs of the bearing shield 40 and the tabs of the
bearing shield 50 occupy positions that present an angular offset around the
axis X30 so that they are received in the groove 326 without interfering with
one another. Ignoring this angular offset, the bearing shields 40 and 50 and
the inner ring 32 are arranged symmetrically about the bisector plane of the
rollers 34.
In a variant that is not shown, the axial length of the groove 326 is
sufficient to receive the tabs of two facing bearing shields at the same angular
position about the axis X30. The bearing shields can then be arranged in
completely symmetrical manner about the bisector plane of the rollers 34.
Alternatively, instead of having a single groove 326, the inner ring 32
could present two or more cavities each adapted to receive one of the tabs
441, 445, 541, and equivalent. In such a variant, the rims 327 and 329 are
constituted by isolating projecting portions that lie respectively between said
cavities in the corresponding inner lateral surface 324 or 325.
Figure 8 shows a variant of the bearing of Figures 2, 6, and 7, in an
intermediate state while it is being assembled. The bearing 60 in Figure 8 has
a, end plate or bearing shield 80 that is similar to the bearing shield 50, with a
first portion constituting an annulus 81, a second portion constituting a collar
82, and two tabs that constitute members for holding the bearing shield 80,
one of which is visible in Figure 8 with the reference 841.
The bearing 60 of Figure 8 differs from the bearing of Figure 6 in that it
presents an inner ring 62 with an annular rim 627 projecting from a cylindrical
surface 620 lying between the two inner lateral surfaces of the inner ring 62,
one of which can be seen in Figure 8 under the reference 625. Like the rims
327 and 329 of the bearing 30, the rim 627 forms receiving means adapted to
co-operate with the holder members of the bearing shield 80 formed in
particular by the tabs 841, thereby enabling the bearing shield 80 to be held
on the inner ring 62.
As shown in Figure 7, in the intermediate state where the bearing
shield 50 is merely held against but not yet clamped to the inner ring 32, axial
clearance J51 is left between the inner ring 32 and the annulus 51. More
precisely, the axial clearance J51 is provided between the lateral surface 323
of the inner ring 32 and the facing surface 513 of the annulus 51. The axial
clearance J51 is at a maximum when the tab 541 bears against the rim 327.
The axial clearance J51 may typically be about 0.3 mm. In practice, the axial
clearance J51 may lie in the range 0.05 mm to 0.5 mm. As in the example of
Figure 7, the variant shown in Figure 8 provides axial clearance J81 between
the annulus 81 of the bearing shield 80 and the inner ring 62.
The respective dimensions of the collar 52 and of the inner ring 32 are
determined so as to leave the axial clearance J51. In particular, the length
L52 of the collar 52 is designed to be greater than a length L32 characteristic
of the inner ring 32. The lengths L52 and L32 are taken along the oblique
direction L. The length L52 extends from the face of the tab 541 that is in
contact with the rim 327 to the virtual intersection between the faces of the
collar 52 and of the annulus 51 that face towards the inner ring 32. The
length L32 extends from the face of the rim 327 that comes into contact with
the tab 541 to the virtual intersection between the inner lateral surface 325
and the lateral surface 323.
After the screw 29A has been tightened into the nut 29B, the axial
clearance J51 vanishes and the annulus 51 comes into contact with the lateral
surface 323, as shown in Figure 6. With the bearing 30 in the tightened or
assembled state, the tabs of the bearing shield 50, including the tab 541,
move to a distance apart from the rim 327 that corresponds substantially to
the axial clearance J51. When the frustoconical portion 242 of the flange
24B, the collar 52, and the inner lateral surface 325 are in contact, the
transmission of forces and in particular axial forces is optimized and the
bearing 30 then performs its bearing function. The collars 42 and 52
withstand the axial and radial forces that are generated when the flanges 24A
and 24B are tightened by the conical screw 29A and nut 29B.
While the screw 29A is being tightened in the nut 29B, the axial
clearance J51 and the flexibility conferred on the collars 42 and 52 by the
notches 431 to 438 and equivalent enable the bearing shields 40 and 50 to be
positioned easily and optimally against the inner ring 32. In particular, the
way the collars 52 are accommodated against the inner lateral surface 325
provides considerable tolerance in the relative positioning of the inner ring 32
and the flanges 24A and 24B. Consequently, the components of the bearing
and in particular the inner ring 32, the bearing shields 40 and 50, the conical
screw 29A and the conical nut 29B can all be made with relatively flat
machining tolerances, thereby making them inexpensive.
In a variant that is not shown, the means for receiving the tabs of the
bearing shield may be constituted by two annular grooves, each located within
a respective one of the frustoconical inner lateral surfaces so as to form two
rims adapted to co-operate with such tabs. Such a configuration serves to
minimize the axial size of the inner ring, and thus of the bearing, in
circumstances where the axial forces can be transmitted via a frustoconical
inner lateral surface of relatively small extent.
In addition to withstanding axial forces well, a bearing in accordance
with the present invention is found to be particularly simple to fabricate and
assemble. Such a bearing requires a small number of different components
since the two bearing shields can be identical and since the components can
be machined with relatively slack tolerance, thereby reducing their costs. In
addition, the inner ring is relatively simple to machine since the groove 326 or
the rim 627 can be machined in the same turning operation as is used to
produce the frustoconical inner lateral surfaces. Furthermore, the bearing
shields may be made by simple cutting out and stamping operations, and the
holder members such as the tabs 441 and 445 can even be folded after a
bearing shield has been mounted on the inner ring, after being previously cut
out.
A puller system in accordance with the invention is thus relatively easy
to fabricate and assemble. In addition, the bearing it includes provide high
loading capacity at low cost.
Other embodiments of the invention are also possible and any
technically feasible combination of the above-specified technical
characteristics constitutes an additional variant.
By way of example, the present invention may be applied to a sealed
maintenance-free bearing having bearing shields that include gaskets to
provide sealing between the bearing shields and outer rings, such as lip seals.
Furthermore, the receiver means formed by the above-described
annular collars could be made by projecting portions located on a fraction only
of the circumference of an inner ring, in positions that correspond to the
positions of the holder members of the respective bearing shields.
In another variant that is not shown, the two portions and the inner
lateral surfaces may be made up respectively of two successive frustoconical
surfaces that are inclined differently relative to the axis of the bearing.
In yet another variant that is not shown, the second portions and the
inner lateral surfaces may be partially toroidal in shape.
CLAIMS
1. A bearing (30; 60) for a puller system (1) of a weaving loom, the bearing
comprising:
• rollers (34) of substantially cylindrical shape;
• an inner ring (32; 62) and an outer ring (36) extending respectively on
either side of said rollers (34) with respect to a radial direction (Y), said inner
ring (32; 62) and said outer ring (36) defining respective inner and outer
cylindrical raceways (321; 361), the inner ring (32; 62) comprising two lateral
surfaces (322, 323) extending radially and disposed in an axial direction (X)
on either side of said inner raceway (321), and two inner lateral surfaces (324,
325; 625) each presenting a generally frustoconical shape and diverging on
going away from a central axis (X30) of said bearing (30; 60); and
. two bearing shields (40, 50; 80) disposed respectively on either side
of said inner raceway (321) in said axial direction (X) and designed to be
placed between two lateral flanges (24A, 24B) belonging to said puller system
(1);
said bearing being characterized in that each bearing shield (40, 50;
80) comprises:
• a first portion (41, 51; 81) extending radially over all or part of the
corresponding lateral surface (322, 323); and
. a second portion (42, 52; 82) adapted to cover a substantial portion of
the corresponding inner lateral surface (324, 325; 625).
2. A bearing (30; 60) according to claim 1, characterized in that each bearing
shield (40, 50; 80) comprises holder members (441, 445, 541; 841), and in
that said inner ring (32; 62) comprises receiving means (326, 327, 329; 627)
for receiving said holder members (441, 445, 541; 841), said receiving means
(326, 327, 329; 627) being adapted to co-operate with said holder members
(441, 445, 541; 841) so as to hold each bearing shield (40, 50; 80) on said
inner ring (32; 62).
3. A bearing (30; 60) according to claim 2, characterized in that said holder
members comprise at least one elastically deformable tab (441, 445, 541;
841) that locally extends said second portion (42, 52; 82) and that presents an
end that is curved towards said inner ring (32; 62) so as to hold each bearing
shield (40, 50; 80) to the inner ring (32; 62).
4. A bearing (30; 60) according to claim 3, characterized in that said receiving
means are formed by at least one rim (327, 329; 627) formed on said inner
ring (32; 62) and between said two inner lateral surfaces (324, 325; 625).
5. A bearing (30; 60) according to claim 3 and claim 4, characterized in that
said inner ring (32; 62) presents at least one cavity adapted to receive at least
one tab (441, 445, 541; 841), said rim (327, 329; 627) being formed by
projecting portions lying between respective cavities in the respective inner
lateral surface (324, 325; 625).
6. A bearing (30; 60) according to claim 5, characterized in that said cavities
are formed by a single groove (326) that is formed between said two inner
lateral surfaces (324, 325; 625) and that is annular in shape and symmetrical
about the bisector plane (Y30) of said bearing (30; 60).
7. A bearing (60) according to claim 4, characterized in that said rim (627) is
formed projecting on a cylindrical surface (620) between said two inner lateral
surfaces (625).
8. A bearing (30; 60) according to any preceding claim, characterized in that
the respective dimensions (L52; L32) of each second portion (42, 52; 82) and
of the corresponding inner ring (32; 62) are determined so as to leave, after
assembly of the bearing (30; 60), an axial clearance (J51) between each
second portion (42, 52; 82) and the corresponding inner ring (32; 62).
9. A bearing (30; 60) according to any preceding claim, characterized in that
each second portion (42, 52; 82) is formed by a collar that extends the
corresponding first portion (41, 51; 81) that is in the form of a substantially flat
annulus that extends radially facing the corresponding lateral surface (322,
323).
10. A bearing (30; 60) according to any preceding claim, characterized in that
each second portion (42, 52; 82) is formed by a plurality of sectors (421; 422;
423; 424; 425; 426; 427; 428) that are separated in pairs by notches (431;
432; 433; 434; 435; 436; 437; 438), each sector (421; 422; 423; 424; 425;
426; 427; 428) extending substantially along a direction (L) that has a radial
component and an axial component.
11. A bearing (30; 60) according to claims 9 and 10, characterized in that said
notches (431; 432; 433; 434; 435; 436; 437; 438) extend into said annulus
(41, 51; 81).
12. A bearing (30; 60) according to claim 10 or claim 11, characterized in that
the number of notches (431; 432; 433; 434; 434; 436; 437; 438) lies in the
range 4 to 10.
13. A bearing (30; 60) according to any preceding claim, characterized in that
the frustoconical surfaces of each inner lateral surface (324, 325; 625) and of
each second portion (42, 52; 82) present a half-angle (a) at the apex lying in
the range 20° to 60°.
14. A puller system (1) for a weaving loom including at least one link rod (20,
21, 24) and at least one lever (22), the system being characterized in that said
link rod (24) and said lever (22) are connected together by means of a bearing
(30; 60) according to any preceding claim, said lateral flanges (24A; 24B)
being constituted by said link rod (24) and being secured to said inner ring
(32; 62) by means of a biconical bolt and nut fastener (29A, 29B) tightened
against said lateral flanges (24A; 24B).
The bearing (30) for a loom puller system comprises rollers (34), and inner and outer ring (32, 36), the inner ring (32) having two lateral surfaces extending radially and being disposed in an axial direction on either side of an
inner raceway, together with two inner lateral surfaces (324, 325) that are generally frustoconical, the bearing also having two bearing shields (40, 50) disposed respectively on either side of the inner raceway (321) and designed to be placed between two lateral flanges (24A, 24B). Each bearing shield (40,
50) has a first portion (41, 51) that extends radially facing all or part of the corresponding lateral surface (322, 323) and a second portion (42, 52) adapted to cover a substantial portion of the corresponding inner lateral surface (324, 325).
