Field of Invention:
The present invention relates to an improved rope attachment on extension boom for pick and
carry type crane and more particularly an improved rope attachment method on telescopic
booms for use on Pick and Carry type Cranes which describes an improved work machine
boom having extension and retraction telescopic motion through a pair of ropes each for
extension and retraction motion of extension boom. These extension and retraction ropes are
attached to the boom so as to telescopically extend the boom and telescopically retract the
boom when either of extension retraction rope is pulled within the complete telescopic boom
assembly.
Background of the Invention:
In the known that pick and carry types of mobile hydraulic cranes have a telescopic boom
assembly for lifting and handling the load. The boom assembly comprises of an outer fixed
boom (101) attached to the crane at rear end and at least one or more extension boom
members, which are disposed inside the fixed outer boom. Hydraulic cylinder is connected
between outer fixed and 1st first extension boom member provided for telescopic driving in
and out the first extensile boom (102). In the event of two or more extension boom members
from the fixed outer boom, a multiple of hydraulic Ram means or a combination of Hydraulic
ram and synchronized extension using extension (104) and retraction ropes (105) or chains
are operated over a set of pulley or rollers (103). These pulleys are attached to first extension
member while extension and retraction rope is routed from fixed outer boom to second
extension boom member via the pulleys mounted on first extension boom member. Extension
and retraction rope have a rope attachment and rope crossover arrangement on second
extension boom (106) as shown in Figure 1 of the accompanying drawings.
Further extension and retraction ropes are guided from one side of second extension boom to
its top surface and then back to the other side. This is for achieving rope attachment and rope
crossover to one side to the other side of second extension member. This rope attachment and
rope crossover is achieved by set of blocks fixed to both side walls (107) at rear end of
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second extension boom. There is separate block for extension rope attachment and rope
crossover and separate block for retraction rope attachment and rope cross over (108).
In case of the extension rope, one end of the rope is fixed on the outer boom. The rope is
further routed from front side pulley on the first extension boom towards rear of second
extension boom. On second extension boom the extension rope is guided from side towards
the top surface of boom with a block fixed to the side of boom. Prom the top surface
extension rope is further guided to the other side of boom with another side fixed block on
other side of the boom. From here extension rope is further guided to first extension boom
pulley and back to Outer boom. This end of extension rope is then also fixed on the outer
boom.
Similarly one end of the retraction rope is also fixed to outer boom and the other end of
retraction rope is routed from the rear side pulley mounted on the ~rst extension boom and
further rope is routed to second extension boom from side to top surface and again towards
the other side of second extension boom. Further the retraction rope is routed from pulley on
first extension boom and fixed to the outer boom in a similar way to extension rope as shown
in Figure 1.
The disadvantage of such kind of arrangement is that the rope routing from side to top and
back to the other side of second extension boom is susceptible to damages from rubbing with
inside walls and various plate comers of second extension boom while extension and
retraction of booms.
Another disadvantage of this kind of arrangement is and sharp turns. These sharp turns open
strand of ropes and reduces load carrying capacity and service life of rope.
Yet another disadvantage of this arrangement is that the extension and retraction ropes are
pulled to tension while assembly of telescopic Outer boom. While pulling of ropes, the ropes
get damage from comers of second extension boom as the rope is routed from side wall to top
surface and back to side wall of second extension boom.
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The above disadvantages of the known prior art are overcome by the proposed improved
system of the present invention wherein there is provided an improved rope attachment
method on telescopic booms for use on Pick and Carry type Cranes having extension and
retraction telescopic motion through a pair of ropes each for extension and retraction motion
of boom.
Object of the Invention:
The objeCt of this invention is to provide a new arrangement rope attachment and rope cross
over in a smooth manner without need of ropes passing from top surface for routing to other
side of second extension member. This arrangement is fixed at middle rear end of second
extension boom in order to obviate the disadvantages sited above; a unique rope attachment
and crossing arrangement is proposed which is free of disadvantages like rope rubbing with
first extension inside walls, sharp turn in ropes and damage while pulling of ropes.
Brief Description of the Accompanying Drawing
We shall now describe the present invention with reference to accompanying drawings which
are given by way of illustration but does not restrict the scope of present invention. These
accompanying drawings provide further objects and advantages of this invention which will
be more apparent from the ensuing description when read in conjunction with the
accompanying drawing and wherein:
Fig. 1 shows Crane Boom assembly with fixed outer boom, first and second extension booms
with hydraulic ram and extension, retraction ropes.
Fig. 2 shows plan view of semi circular pulleys mounted on both faces of plate.
Fig. 3 shows plate with semi circular pulleys mounted on rear and mid plane of second
extension member.
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Fig. 4 shows 3D views of semi circular pulleys mounted on both faces of plate along with
rope guide plate.
Summary of Invention
According to the present invention there is provided an improved rope attachment on
extension boom for pick and carry type crane attachment and routing arrangement
related to a crane boom assembly comprising of a fixed outer boom with at least two
or more extension booms,
(a) the first extension boom being extended telescopically with a hydraulic cylinder
and (b) a second extension boom provided with a pair of extension and retraction
ropes,
the extension rope being attached to one side of the fixed outer boom at its one end
and is routed over a pulley fixed on the same side of the front side of the first
extension boom, the extension rope is being routed towards the same side but on
the rear side of the second extension boom then extension rope is routed to its other
side whereas the rear side being provided with an arrangement of two semi-circular
pulleys mounted on opposite sides of a plate with a typical profile but conveniently
facing opposite to each other so that the said plate with the said typical profile along
with the semi-circular pulleys capable of being mounted on to the rear end of the
second extension boom in a horizontal position, one of the said semi circular pulleys
facing up side and the other semi-circular pulley facing down side of the second
extension boom and one pulley with its curvature facing rear side and the other
pulley with its curvature facing the front side of the second extension boom, the said
extension rope from the other side of the second extension boom being routed back
to the fixed outer boom through another pulley on the first extension boom, and the
said retraction rope being routed similarly from the fixed outer boom to the second
extension boom through the said first extension boom and back to the fixed outer
boom.
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In a circular guide strip is being provided over the circumference of each semicircular
pulley mounted on the said plate with a typical profile.
In the said plate with a typical profile and the two semi-circular pulleys mounted on
opposite sides of the plate being fixed at the rear side of the second extension boom
at approximately its mid -plane from bottom to the top.
The extension and retraction ropes pass through the boom and the semi- circular
pulley in such a manner that the extension and retraction ropes entering through one
side of the second extension boom and semi-circular pulley pass out of the other
side of the second extension boom and semi circular pulley smoothly.
The arrangement is mounted on cranes such as pick and carry type of cranes but
not limited to this application only.
One of the objectives of the present invention is to provide a rope attachment and crossing on
second extension boom which is facilitated via a set of semi circular pulley sections attached
to a plate. In Figures 2 and 4 is shown a semi circular pulley I and semi circular pulley 2
which are fixed on to a plate.
Another objective of the invention is to fix both the semi circular pulleys (201) and (202) on
to the opposite side of plate (204) and to place them opposite to each other. As shown in
Figure 2, both these pulleys have a guide strip (203). The guide strip (203) assists for routing
extension and retraction rope and also for preventing the rope to come out of the semi circular
pulley while telescopic extension and retraction of boom and also while carrying out
assembly of telescopic boom.
Yet another objective of the invention is to attach the plate with a set of semi circular pulley
sections (301) to the rear end of second extension boom but at a mid surface from bottom to
top as shown in Figure 3. The plate (402) on which the semicircular pulleys (401) (404) are
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fixed has a special profile to provide more contact area with body of second extension boom
as shown in Figure 4.
With this arrangement the extension and retraction ropes can pass from one side of the
second extension boom to the other side by smooth guiding on semi circular pulley and
without any need to pass from top surface of second extension boom. With such arrangement
there is no need of guiding rope with blocks to change direction of rope while passing from
one side to the other side of the second extension boom.

WE CLAIM:
1. An improved rope attachment on extension boom for pick and carry type crane
attachment and routing arrangement related to a crane boom assembly comprising
of a fixed outer boom with at least two or more extension booms,
(a) the first extension boom being extended telescopically with a hydraulic cylinder
and (b) a second extension boom provided with a pair of extension and retraction
ropes, the extension rope being attached to one side of the fixed outer boom at its
one end and is routed over a pulley fixed on the same side of the front side of the
first extension boom, the extension rope is being routed towards the same side but
on the rear side of the second extension boom then extension rope is routed to its
other side whereas the rear side being provided with an arrangement of two semicircular
pulleys mounted on opposite sides of a plate with a typical profile but
conveniently facing opposite to each other so that the said plate with the said typical
profile along with the semi-circular pulleys capable of being mounted on to the rear
end of the second extension boom in a horizontal position, one of the said semi
circular pulleys facing up side and the other semi-circular pulley facing down side of
the second extension boom and one pulley with its curvature facing rear side and the
other pulley with its curvature facing the front side of the second extension boom, the
said extE!nsionrope from the other side of the second extension boom being routed
back to the fixed outer boom through another pulley on the first eXtension boom, and
the said retraction rope being routed similarly from the fixed outer boom to the
second extension boom through the said first extension boom and back to the fixed
outer boom.
2. An improved rope attachment on extension boom for pick and carry type crane
attachment as claimed in claim 1, wherein in a circular guide strip is being provided
over the circumference of each semi-circular pulley mounted on the said plate with a
typical profile.
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3. An improved rope attachment on extension boom for pick and carry type crane
attachment as claimed in claim 1, where in the said plate with a typical profile and
the two semi-circular pulleys mounted on opposite sides 'of the plate being fixed at
the rear side of the second extension boom at approximately its mid -plane from
bottom to the top.
4, An improved rope attachment on extension boom for pick and carry type crane
attachment and routing arrangement as claimed in claim 1, wherein the extension
and retraction ropes pass through the boom and the semi- circular pulley in such a
manner that the extension and retraction ropes entering through one side of the
second extension boom and semi-circular pulley pass out of the other side of the
second extension boom and semi circular pulley smoothly.
5. An improved rope attachment on extension boom for pick and carry type crane
attachment as claimed in claim 1, wherein the arrangement is mounted on cranes
such as pick and carry type of cranes but not limited to this application only.