CA1252491A

CA1252491A - Tackle mechanism

Info

Publication number: CA1252491A
Application number: CA000506211A
Authority: CA
Inventors: Otto Luginbuhl
Original assignee: Willy Habegger AG
Current assignee: Willy Habegger AG
Priority date: 1985-04-12
Filing date: 1986-04-09
Publication date: 1989-04-11
Also published as: DE3513098A1; DE3513098C2; CN1004414B; EP0198273B1; EP0198273A3; CS264336B2; SU1491329A3; ATE36303T1; EP0198273A2; CN86102499A; CS265286A2

Abstract

A b s t r a c t Tackle mechanism The invention relates to a tackle mechanism for lifting and lowering loads, comprising one or more clamp jaw pairs disposed in a housing and having clamp jaws for a continuous cable, the clamp jaws being operable by way of clamp levers and comprising clamp jaw carriers for the clamp jaw pairs, and an actuating mechanism for the opening and closing movement of the clamp jaw pairs.
At least one of the two clamp jaws of each pair is mounted pivotally on a pivot disposed transversely of the cable direction. This ensures uniform cable clamping with reduction of cable and clamp jaw wear.
(Fig. 1)

Description

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Tackle mechanism This invention relates to a tackle mechanism for lifting, lowering and pulling loads, comprising one or more clamp jaw pairs disposed in a housing and having clamp jaws for a continuous cable, the clamp jaws being operable by way of clarlp levers -and comprising clamp jaw carriers for the clamp jaw pairs, and an actuating mechanism for the opening and closing movement of the clamp jaw pairs.
Known tackle mechanisms having two clamp jaw pairs reciprocating in opposite clirections are usually so cons'ructed that the cable is clamped as in a vice having parallel clamp jaws. Parallel guidance of the clamp jaws is obtained by articulating each clamp jaw on the opening and closing mechanism at two points as considered in the cable direction.
This mechanism may consi.st of parallelogram levers, bell cranks or levers with S-shaped closing cams.
- The fact that the cable on the load side of a contacting clamp jaw pair is in every case thinner than on the side remote from the load, i.e. because it undergoes transverse contraction through the traction, results in the parallel clamp jaws exerting excessive pressure on the cable and excessive stress on the corresponding clamp lever pair near `~ S~24~

the load-remote end. On the other hand, the clamp lever pair on the load side is always subjected to less loading. Given a small cable diameter of up to about 15 mm the transverse contraction of the cable is small but on the other hand the elastic deformation of the opening and closing mechanism is relatively considerable so that the lack of uniformity of the pressure on the cable hardly takes any adverse form. In the case of lQ larger cable diameters, however, the non-uniform pressure frequently results in local pitting.
Consequently, there is considerable cable and clamp jaw wear during load lowering. In addition, there is no proof of parts of the opening and closing - 15 mechanism being secure against fracture.
Another known tackle mechanism comprises two automatic gripper blocks provided ~ith clamp jaws, one of these blocks alternately clamping and driving the cable while the other block slides freely along the cable. For safety reasons it is desirable for the two blocks or their clamp jaws to be subjected to different wear. This ensures that one gripper block al~ays operates reliably. To ensure uneven wear, two different gripper blocks or gripper blocks with different clamp jaws are used. The di~ferent 3~
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construction of the clamp jaws can be obtained in various ways, e.g. by different lengths, by using different materials, by different cable grooves, or the like. In one embodiment, one of the clamp jaws can slightly incline just one of the two gripper blocks with respect to the longitudinal axis of the other clamp jaw. The object of this is to-make the wear of this block or its clamp jaws less than the wear of -the clamp jaws of the other block, so that the other block wears more quickly, thus ensuring alternate replacement. Alternate replacement means that one of the two blocks is intended always to operate reliably. These steps do not decisively affect the above problems concerning obtaining uniform wear at both clamp jaws, and the known steps on the contrary point in an opposite direction.
The object of the invention is to provide a tackle meehanism for lifting, lowering and pulling loads of the kind referred to hereinbefore, which is dist.inguished by uniform cable clamping and reduction of eable and elamp jaw wear at both jaws.
To this end, in a tackle mechanism of the kind referred to, aecording to the invention, at least one of the two clamp jaws of each clamp jaw pair is pivotally mounted on a pivot disposed transversely ~Z5~'3~

of the cable directionl and the pivotally mounted clamp jaws are articulated at least at one end on the associated clamp levers and the associated clamp jaw carriers each have a corresponding aperture for the pivots for the clamp jaws. According to another embodiment, in which again at least one of the two clamp jaws of each pair is pivotally mounted on a pivot disposed transversely of the direction of the cable, the invention teaches, with lndependent significance, that the pivotally mounted clamp jaws are articulated at least at one end on the associated clamp ~aw carriers and the associated clamp levers each have a corresponding aperture for the pivots for the clamp jaws.
According to the teaching of the invention, the pivotally mounted clamp jaws can assume either a parallel or oblique position to the associated co-acting jaw depending on the particular phase of movement and the load at any time, so that the transverse contraction resulting from application of the traction and the transverse compression of the cable produced by the effect of the clamp jaw biasing force, can no longer result in excessive pressure near the load-remote end of the clamp jaws. - In the case of manually operated tackle ` lZS~4~1 mechanisms, the weight and price play an important part. The tackle mechanism according to the invention allows increased material stressing as a result of distinct load conditions by a statically well-defined construction. The number of components can thus be reduced and this in turn reduces the ~weight and price compared with the known parallel guidance of the clamp jaws. In addition, wear on the cable and clamp jaws is reduced with increased 1~ safety against fracture, so that the tackle mechanism according to the invention is also distinguished by considerable cost-effectiveness to the user.
These are the main advantages of the invention.
Further features essential to the invention are indicated hereinbelow. According to a preferred embodiment of the invention, the two clamp jaws of each pair are mounted pivotally. The pivots for the pivotally mounted clamp jaws may be constructed as push-in or pull-out bolts, so that it is a simple matter to fit and dismantle the.pivotally mounted clamp jaws. The introduction or removal of a cable transversely of the cable direction is rendered possible as a result of the easy removal of the pivotally mounted jaws. According to the invention, the pivotable jaws are mounted pivotally in each i;~5Z~
.

case between two opposite clamp levers or clamp jaw carriers and hence positioned for symmetrical stresses. Finally, the pivotally mounted clamp jaws can be constructed as slender and in every case resiliently yielding clamp jaws, so that optimized distribution of transverse pressure at the cable is obtained in addition to pivotability, due to the resilient yielding feature.
Accord:ing to the invention, the clamp lever action can be on a decreasing scale as in the parallelo-gram type c:Lamp mechanism. Alternatively the clamp lever action may be progressive as in the bell crank mechanism. Finally, the clamp lever ation can be substantially proportional to the closing travel as in the closing cam type mechanism.
In every case substantially uniform transverse press~lre is always obtained on the associated cable.
The invention will be explained in detail hereina~ter with reference to the drawing illustrating just one exemplified embodiment Fig. 1 shows a tackle mechanism according to the invention in diagrammatic side elevation with pull levers articulated on the clamp levers at the top.
Fig. 2 is a detail of the subject shown in ~ZSZ4~1 Fig. l having a pivotally mounted clamp jaw with external clamp levers and internal clamp jaw carriers.
Fig. 3 is an exploded view of the subject of Fig. 2.
Fig. 4 is a modified embodiment of the subject of Fig. 2, in which the l:wo clamp jaws are pivotally ~mounted with external clamp jaw carriers and internal clamp levers.
Fig. 5 is an exploded view of the subject of Fig. 4.
Fig. 6 is a modifiecl embodiment of the subject of Fig. 1 having two clamp lever pairs with a point of articulation at cable height ~a = 0) and pivotally mounted coacting jaws.
Fig. 7 is a vert cal section on the line A-B through the subject of Fig. 6.
Figs. 8 to ll are diagrams showing ~he clamp jaws acting on the cable during the lifting and lowering of a load.

-~ lZ~Z4~:1 The drawings show a tackle mechanism for lifting, lowering and pulling loads, comprising a plurality of, namely two, pairs of clamp jaws 2 disposed in a housing 1 and comprising clamp jaws 5, 6 for a continuous cable 7, the jaws being operable via clamp levers 3, 4, and also comprising clamp jaw carriers 8, 9 for the clamp jaw pairs 2 and an actuating device lO for the openlng and closing movement and the reciprocating movement or the clamp jaw pairs, l.e. clamp jaws 5, 6~ The clamp jaw carriers 8, 9 are articulated with the clamp jaw pairs 2 on ^ockers ll. The latter are articulated on the housing l. The pivot axes 12, 13 of the clamp jaw carriers 8, 9 and rockers l]. are arranged in axis-parallei relationship to one another and transversely of the cable direction. The cable jaw carriers 8, 9 are constructed as bearing cheeks or bearing levers for the clamp jaws 5, 6 and clamp levers 3, 4. The clamp jaw carriers 8, 9 are respectively suspended from a front and rear rocker 11 as considered in the cable direction. The rockers 11 of each clamp jaw carrier 8, 9 are disposed parallel to one another. The rockers ll may be constructed as two-armed members in which case the clamp jaw carriers 8, 9 are suspended in each ~2r~

case between the -two arms. The pivot axes 13 of the rockers 11 are formed by transverse connecting bolts of the housing 1, which is frequently made in two parts.
The clamp jaws 5, 6 of each pair 2 are articulated by means of the clamp levers 3, 4 on pull levers 15 of the actuating mechanism 10. Closing springs 16 are disposed between the pull levers 15 and the associated clamp jaw carriers 8, 9.
The pull levers 15 of the actuating mechanism 10 can be pivoted on the clamp levers 3, 5 of the clamp jaw pairs 2 at the top or bottom or else at the top and bottom alternately and are also articulated on an actuating lever 17 of the actuating mechanism 10. The pivot axis 12 between one clamp jaw carrier 8, 9 and a rocker 11 is provided as a point of engagement for a reverse mocion lever 18 of the actuating mechanism 10.
At least one of the two clamp jaws 6 of each pair 2 is pivotally mounted on a pivot 23 extending transversely of the cable direction. According to the invention, both clamp jaws 5, 6 of a pair

2 may be pivotally mounted. The pivots 20 of the pivotally mounted clamp jaws 5-and 6 are in the form of push-in or pull-out bolts.

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According to one e~emplified embodiment, the pivotally mounted clamp jaws 6 are articulated at one end on the associated clamp levers 3 while the associated clamp jaw carriers 8 each have a corresponding aperture 19, e.g. of kidney shape, for the pivots 12 of the clamp jaws 5. - According to another e~emplified embodiment, the pivotally.
mounted clamp jaws 6 are articulated at one end on the associated clamp jaw carriers 8 while the associated clamp levers each have an aperture 19, e.g. a kidney-shaped aperture, for the pivots 20 of the clamp jaws 5. It is also possible for the pivotable clamp jaws 5, 6 to be mounted each to pivot between two opposite clamp levers 3, ~
or clamp jaw carxiers 8, 9. The pivotally mounted clamp jaws 5, 6 are constructed as slender and hence resilient].y yielding clamp jaws.
The tension on the pull levers 15 and on the cable 7 in the embodiment shown in Figs. 1, 2 and 4 forms a force couple spaced by the amount a.
Corresponding counter-acting forces must be taken by guide means, preferably the rockers 11. Their points of articulation on the clamp jaw carriers 8, 9 are therefore situated far apart, i.e. in accordance with the spacing b. - If a construction lZ~

is embodied as shown in Fig. 4, the guides have to take only the deadweight of the clamp jaw pairs 2, because the points of articulation of the pull levers 15 are at cable height and hence a = 0.
If two clamp lever pairs 3, 4 are articulated, the pull levers 15 can in fact provide stabilization of the clamp jaw pairs 2 in the direction of the cable. Only one introduction point c is then required to ensure accurate alignment of adjacent clamp jaws pairs 2.
Referring to Fig. 8, when a load is lifted, the top clamp jaw pair 2a slides on the cable 7 with a subsequent engagement action, the clamp jaws 5, 6 being pressed resiliently into contact.
The bottom clamp jaw pair 2b clamps fast and lifts the load, its clamp jaws 5, 6 being pressed agalnst the cable 7 by lever action. Referring -to Fig.
9, the top clamp jaw pair 2a clamps fas-t and lifts the load, while the clamp jaws 5, 6 are pressed against the cable 7 by lever action. On the other hand, the bottom clamp jaw sliding on the cable 7 engages subsequently and its clamp jaws 5, 6 are only resiliently pressed against the cable 7.
Referring to Fig. 10, the top clamp jaw pair ~z~

2a carries half the load for lowering and is clamped fast against the cable 7 by lever action, and the load is lowered. The bottom clamp jaw pair 2b also carries half the load and is clamped fast by lever action, but allows the cable to continue to slide with a braking effect during the subsequent engagement action. Referring to Fig. 11, the top clamp jaw pair 2a engages subsequently and carries half the load, i.e. is clamped by lever action and allows the cable 7 to slip through with braking effect. The bottom clamp jaw pair 2b also in turn carries half the load and is clamped by lever action, but the load is lowered.
According to another embodiment of the invention of independent significance, in which again at least one of the two clamp jaws 5, 6 of each pair 2 is pivotally mounted, the pivotally mounted clamp jaws 5, 6 are subjected to the action of a yoke transversely of the cable direction. In this embodiment, therefore, the pivotal mounting of the clamp jaws 5, 6 can be obtained by means of a tilting type joint, a support in the form of a rubber block, or the like.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A tackle mechanism for lifting, lowering and pulling loads, comprising one or more clamp jaw pairs disposed in a housing and having clamp jaws for a continuous cable, the clamp jaws being operable by way of clamp levers and comprising clamp jaw carriers for the or each clamp jaw pair, and an actuating mechanism for the opening and closing movement of the or each clamp jaw pair, characterised in that at least one of the two clamp jaws of each clamp jaw pair is pivotally mounted on a pivot disposed transversely of the cable direction, and the pivotally mounted clamp jaws are articulated at least at one end on the associated clamp levers and the associated clamp jaw carriers each have a corresponding aperture for the pivots for the clamp jaws.

2. A tackle mechanism for lifting, lowering and pulling loads, comprising one or more clamp jaw pairs disposed in a housing and having clamp jaws for a continuous cable, the clamp jaws being operable by way of clamp levers and comprising clamp jaw carriers for the clamp jaw pairs, and an actuating mechanism for the opening and closing movement of the clamp jaw pairs, characterised in that at least one of the two clamp jaws of each clamp jaw pair is pivotally mounted on a pivot disposed transversely of the cable direction, and the or each pivotally mounted clamp jaw is articulated at least at one end on the associated clamp jaw carrier and the or each associated clamp lever has a corresponding aperture for the pivot for the associated clamp jaw.

3. A tackle mechanism according to claim 1 or 2, characterised in that the two clamp jaws of each pair of clamp jaws are pivotally mounted.

4. A tackle mechanism according to claim 1 or 2, characterised in that the two clamp jaws of each pair of clamp jaws are pivotally mounted by means of push-in bolts.

5. A tackle mechanism according to claim 1 or 2, characterised in that the two clamp jaws of each pair of clamp jaws are pivotally mounted in each case between two opposed clamp levers or clamp jaw carriers.

6. A tackle mechanism for lifting, lowering and pulling loads, comprising one or more clamp jaw pairs disposed in a housing and having clamp jaws for a continuous cable, the clamp jaws being operable by way of clamp levers and comprising clamp jaw carriers for the or each clamp jaw pair, and an actuating mechanism for the opening and closing movement of the or each clamp jaw pair, characterised in that at least one of the two clamp jaws of the or each pair is pivotally mounted and the or each pivotally mounted clamp jaw is subjected to the action of a yoke transversely of the cable direction.