CA1285121C - Wedge-type rope socket connection and method - Google Patents

Abstract

ABSTRACT

WEDGE-TYPE ROPE SOCKET CONNECTION AND METHOD

Disclosed is a socket wedge connection for a wedge-type rope socket for an excavating bucket or the like comprising a relatively elongated socket having a larger end and a smaller end with a tapered passage extending from one end to the other. A rope in the passage is looped upon itself to provide two lengths of rope in the passage with a loop adjacent the larger end. A relatively elongated wedge is between the two lengths, the wedge having a pair of longitudinally-extending wedge-forming element with collapsible inserts therebetween for relieving pressure on the two lengths of rope.

Description

File 229 WEDGE-TYPE ROPE SOCKET CONNECTION AND METHOD

BACKGROUND AND SUMMARY_OF INVENTION:
This invention relate~ to a wedge-type rope socket connection and method and, more particularly, to a connection which is readily disassembled in the field when used as part of the dragline, hoist line or dump line of a dragline bucket or any of the attaching lines for a cable shovel, cable hoe, etc.
The general environment where th invention finds application is seen in co-owned U.S~ Patent 3,681,80~. For example, wedge-type rope sockets are employed to secure the wire rope~ forward and above the bucket for operating the same. Es~entially, ~he socket is a relatively elongated mamber having a smalLer end and a larger end and a tapered passage extending therethrough. The wire rope i5 looped on itself and held in place by a wedge.

85~

At present, these wedyes, because o their dificulty of removal, are being blown out by various forms of cannons, are being pressed out in shops, etc.
Almost every form of present removal requires either a large sledge, a pendulum ram, or cannon, all of which could be very dangerous because of the resultant force required to remove the wedye. In addition to the safety factor, the currently used construction results in expensive down-time in ~h~ case o~ rope chan~e-out. Some o~ the !0 larg~ machlne~ lncur a down-time cost o~ approximately S5,000 per hour and the change-out of a dump rope can take as long as three to four hours. This also applies to such prior art expedients as seen in U. S. Patent No.
3,905,711, The invention avoids these disadvantages throuc3h the provlsion of a multi-part wedge which includes a pair of longitudinally extending wedge ~orming means along with a collapsible insert means t.here between. More partlcularly, the insert means can take the form of wedge shaped parts slidable relative to each other when the constraining force exerted by the rope loop is removed or by a heat destructible element, or both.
More particularly, one aspect of the invention pertains to a wedge apparatus for a wedge-type rope socket connection of an excavating bucket comprising a wedge having a small end ~ and larger end and comprising two wedge-forming halves -~ pi~otally interconnected adjacent the small wedge end, the wedge halves are equipped with confronting surfaces ad~acent the larger wedge end. An insert is adapted for insertion between the confronting surfaces, the insert comprising a plurality of longitudinally tapered blocks adapted to be stacked together between the confronting surfaces, the tapered blocks further belng adapted to slide relative to each other in the absence of a longitudinal constraint.

,~, Another aspect oE the i.nverltion pertains to a Method of manipulatin~ a wedge-type rope soclcet connection for an excavating bucke-t or the like comprising providiny a relatively elongated socket having a tapered passage extending Erom one end to the other, installing a multiple-part wedge and rope in the passage wherein the wedge includes outer tapered members and a collapsible insert and, when disassembly of the connection is required, colLapsing the insert. The insert includes a plurality oE stacked tapered blocks slidable with respect to each other upon removal. of force sustaining the blocks in a stack, and -the step of collapsing the insert includes removal of the sustaining Eorce.
Still Eurther, the invention cornprehends a collapsible support Eor resisting a clamping force comprising three stacked, longitudinally tapered members arranged to slide relative to each other, and wedge-forming means including an element adjacent each end member of the stack for applying a compressive load to the stac]c end members. The middle member : of the three stacked members has an angle of taper relative to each of the adjacent end members, the angle of taper having a tangent greater than the coefficient of friction between adjacent ones of the stacked members~ Housing means i5 operably associated with the three members and releasably constrains the same against sliding movement longitudinally 25 relative to each other. Thus, when the constraining housing means is removed, -the middle member of the stacked members automatically is ejected relative to the ad~acent end members to relieve the compressive load.
Other aspects and advantages of the invention may be seen in the details of the ensuing specification.
The invention is described in conjunction with the accompanying drawing, in which --FIG. 1 is a fragmentary perspective view of a portionof a dragline featuring the socket with the inventive wedge;

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~.~85~21 FIG. 2 is an enlarged longitudinal section such as would be qeen along the sight line 2~2 of FIG.
1 ;
FIGS. 3-6 are transverse sectlonal views taken along the ~ight lines 3-3, 4-4, 5-5, and 6-6, respectively, of FIG. 2;
FIG. 7 i~ an exploded perspective view of the socket and wedge of the invention;
FIG. 8 is a perspective disassembled view showiny the wedge about to be inserted into the socket with the wire rope shown in dashed line;
FIG. 9 is a sectional view similar to FIG 2 but with the wire rope severed so as to illustrate the method of diqassembling the connection;

FIG. 10 is a side elevational view of a modified form of wedge insert;
FIG. 11 is a longitudinal sectional view of a modified form of the inention; and FIG. 12 is a perspective view of the insert employed in FIG. 11.
DETAILED DESCRIPTION:
In the illustration given and with reference first to FIG. 1, the numeral 20 designates generally the wedge socket connection which is seen to include a socket 21 adapted 25 to be connected to a shackle, a wire rope 22 looped on itsel~
and a wedge 23 holding the looped rope in place. As mentioned previously, the lnventive connection find utility in appli-cations such as are seen in co-owned U. S. Patent 3,681,808 and re~erence may be made to that patent for additional details 30 of construction, operation and environment not set forth here.
: The socket 21 as can be most re~dily appreciated from FIG. 8 iS a relatively elongated member having a passaga or bore 24 extending there through from the smaller end 25 to the larger end 26. A variety of socket constructions . , ~ ~285~

can be employed in the practice of the invention and the socket illustrated is but one advantageous form -- having a shackle connection at the rear end.
The wedge 23 can be seen ln exploded ~orm in FIG. 7 and i9 seen to include a pa:ir of longitudinally extending wedge forming means 27 and 28.
The identical wedge form:Lng means, i.e., the members 27 and 28 are pinned together by mean~ of a pin 29 -- still referring to FIG. 7. At the larger wed~e end, the members 27, 28 are separated by the insert means generally designated 30.
O~eration Gen rally After the wedge 23 is assembled in the configuratior illustrated in FIG. 8, the wire rope 22 is looped about the larger end of the wedge 23 as illustrated in dotted line to provide two lengths 31 and 32 for mounting in the socket 21. A~ tension T is exerted on the rope 22 as illustrated in FIG. 1, the looped rope and wedge are cinched into place within the socket 21 as illustrated in FIGS. 1 and 2.
When it is necessary to disassemble the wedge and socket, the rope loop is cut -- as by burning -- in the area of the notch or recess 33 provided adjacent the larger end of the upper member 27. It will be noted that a similar recess is provided in the member 28 so that it makes no difference which of the identical members i~
positioned upwardly. Upon severance of the rope 22, the larger end of the insert means 30 is exposed.

In the illustration given, this exposes the larger end of the housing 34 -- see FIG~ 7. The housing 34 is constructed of zinc and hence i5 easily meltable by ~ ~3S~

rneans of a torch. When the rear end wall 34a (still referring to FIG. 7) i5 melted, the element stack 35 collapses. This in turn eliminates pressure on the members 27, 28 and thu~ on the rope length~ 31, 32. There upon, the wedge 23 can be readily removed.
Stacked Element .~
The element 35 includes ~hree ~riction blocks 36, 37 and 38. These blocks are machined at an angle roughly 12 which corresponds ko the coefficient of ~riction of polished steel on polished steel, and therefore these three blocks stacked on top of one another would not stand up but instead slide apart. The advantageous feature of this construction i5 that wikh a very small amount of force on both sides of these three pieces, one can maintain their stability from sliding apart and therefore increase their load carrying capability sub-stantially. However, once the restraining force on the back of these three blocks is removed, i.e., the rear wall 34a of the zinc housing 34, then these blocks collapse readily and allow the wedge forming halves to collapse, thus .acilitating removal of the entire wedge 23 from the socket.
More particularly, in the illustration given, the angle at which the blocks is machined is that angle whose tangent is slightly greater than the coefficient to friction between the adjoining blocks.
It will also be appreciated that in certain instances the zinc housing 34 may be eliminated inasmuch as the uncut rope 22 itself provides the above described ~ ~85~2~L

restraining force~
By the same token, it i9 pog~ib:Le ~0 utilize only a collapsible element such as the block o~ zinc illustrated in FIG. 10. Zinc is chosen because of its relatively low melting point -- of the order of less than 800F. Collapse via melting of the insert means 130 of FIG.
10 is provided by means of a heating coil C embedded therein and equipped with suitable leads for conn2ction to a source of DC current -- virtually always available on the site of dragline bucket operations.
Wed~_Forming Means The details of the wedge forming means 27, 28 can be best appreciated from a considexation of FIG. 7 along with the sectional views of FIGS. 3-6 which are indicated on FIG.

2.
Referring first to FIG. 7, the numeral 39 designates the front bearing area of the wedge which comes into contact with its symmetrical partner when the wedge is assembled.
Just rearward of the front bearing area is the pin boss 40 which is equipped with a hole 42 for the receipt of the pin 29. The pin 29 is employed to pin the wedge halves 27, 28 together to hold them together prior to installation of the composite wedge 23. The pin 29 -- see FIG. 7 -- is equipped with an annular, centrally-longitudinally located recess 41; to accommodate a split locking ring 43 -- see the left hand portion of FIGo 2~
Rearward of the boss 40 -- refexring again to FIG.
7 -- each wedge forming means 27, 28 is equipped with a recess 44 on one longitudinally extending side and an ear 45 on the other longitudinally extending side. These mate together in the fashion illustrated in FIG. 4.

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Also to be noted i~ that each wedge ~orming mean~
or half 27, 28 is equipped with a longitudinally extending groove as at 46 -- best ~een in the upper portion of FIG. 7 relative to the wedge forming half 27. Thi~ groove or recess continues from the front all the way around the rear or larger end to provide a trough for the seatlng of the wire rope loop.
~ he corresponding ears and rece~ses 45, 44 provide for lateral stability of the wedge 23 in the ~ront to back direction ~o that the wedge doe~ not sllp sideways and put torsional loading on the pin 29.
The recesses and ears 44, 45 are similar to recesses and ears 47, 48 provided just rearwardly o~ the recesses and ears 44, 45. The interrelation~hip of the recesses and ears 47, 48 can be appreciated from a consideration of FIG. 5.
The recesses and ears 44, 45 and 47, 48, together with the pin bosses 40 and pin receiving openings 42 provide three pairs of corresponding surfaces along the wedge 23 --which make the wedge very stable longitudinally.

As can be seen, upon installation, the ears 45 fit into the recesses 44 when the wedge is both collapsed and in the full open position. The same applies to the ears 48 and recesses 47.
More particularly, each ear 48 is equipped with a tab 49 (compare FIGS 5 and 7). Each recess 47 is equipped with an~intermediate shoulder 50 for bearing cooperation with the tab 49. In operation, the tab 49 comes into contact with the projection or shoulder 50 and allow~ the wedge halves to open only to a maximum of about 5-1/2" at the back --the amount of opening, of course, depending upon the ~ize : - - 7 -5~

of the wedge and socket ~- which in turn are governed by the capacity of the dragline bucket. In any event, thi limited movement eliminates the load being taken on the pin 29 and the mating surfaces 39 -- but instead has a contact when the wedge is in the full open position between tab 49 and shoulder 50 and on surface 39 which is the bear-ing surface. This take~ all the load, shear load and torsional load, off the pin and allows ~or a more durable and tighter fit.
Area 51 is the back surface area and the area alony which the removable insert 30 slide~ along to effeat engagement of the wedge 23 with the rope 22 and hence the socket 21. Each surface 51 is arranged at a slight angle with reqpect to the longitudinal midplane of the wedge 23, i.e., diverging rear-wardly of the order of about 3 to allow easy in~tallation of the insert 30 but yet virtually a parallel plane for frictional requirements.
In the illustration given, the reax bearing surfaces 51 each have a 1/2" deep groove as at 52 for the support of the insert 30 so that the insert does not slide sideways or become dislodged af~er engagement into the wedge. For this purpose we provide stabilizers in the nature of fins 53 and which are also designated in FIG. 10 by the numeral 153.
As indicated, the inventive wedge has a collapsible insert which allows the wedge to collapse at the back and eliminates pressure on the rope to the side of the socket.
After relieving this pressure, the wedge can be removed much more easily than when the frictional force normally presant would have to be overcome.

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Also, at present, the ~tate of the art wedge~
because o~ difficulty of removal, require extensive force for removal which is dangerous whereaq the new wedge requires only heat as by a cutting torch. This re~ults in decreasing down time of the machine.
The wedge when assembled iq one tight unit and handling iR the same as with the present wedge. However, when the unit is removed, the wedge still remains a9 a unit which can be reused with another in~ert.
].0 The inventive socket-wedge assembly provide~
better rope life and in testing, we have found that rope breaking strength was improved as much as 10-15%
over previous tests run on the same type o~ socket.
The invention also decreases rope slippage.
Another major complaint about wedge-type sockets is the rope slippage when being used in a cyclical appli-cation. With the in~entive wedge, which can be easily removed~ we can now allow for smaller included angles in the sockat and higher wedging action. This higher, tighter wedging action can decrease the possibility of rope slipping before removal is desired.
Still further, the invention reduces damage to sockets. At present, with the cannon or the pendulum ram, there is a certain amount of damage which occurs in the front of the socket due to the high impacts which are required to remove the wedge. With the inventive insert, the wedge is simply and easily removed with very little damage occurring to the socket.

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a~
As a specific example of the wedge 23, the length of each wedge forming mean~ or half 27, 28 is 30", the width about 4-1/2" and the height of each half about 7" at the maximum divergence of the grooved side. The two halveR
27, 28 (see particularly FIG. 7) are moved longitudinally relative to each other to have the various recesses and ears 44, 45 and 47, 48 interengaged. At this stage, the snap ring 43 (see FIG. 3) is inter~itted between confronting recesses so that when the pin 29 i!3 in~erted into the aligned holes 42 in the bosses 40, it can be maintained in place.
Thereupon the insert 30 i9 a~embled utilizing the housing 34 and the three tapered blocks 36-38. These are then inserted into the recess in the housing 34 in the fashion indicated in FIG. 7.
The wire rope 22 is inserted through the opening 24 and folded on itself as indicated in FIG. 8, lying in the grooves 46 of each of the wedge forming halves 27, 28.
With the wedge and rope in the position indicated in FIG.
8, the rope is tensioned so as to pull the assembly into the tapered socket opening 24.
Both sets of recesses and ears 44, 45 and 48, 49 assist in maintaining longitudinal alignment and the removal of shear and torsional forces on the pin 29.
The tabs 49 and shoulders 50 limit the spacing apart of the two halves 27, 28 due to the interposition of the wedge means 30.
When wedge removal is indicated, the rope is severed by burning through in the area of the notch 33-to arrive at the FIG. 9 configuration. Thereafter, 85~

the torch is applied to the now-exposed rear of the zinc housing 34 to free the stacked elements 35. Because these elements are related by an angle greater than the coefficient of friction, the removal of the longitudinal constraint permit~ these elements to slide relative to each other and eject the central element 37. This resultq in a collapse of the wire clamping force so that ea~y removal of the wedge is facilitated -- and without the extraordinary expedients of the prior art.
The collapsible element may be the central block o a stack as seen in FIG. 10 or may be a unitary element which is substituted for the entire stack as seen in FIGS. 11 and 12 where the element is designated 230, having an integral fin or rib 253 and embedded heating coil C.
While in the foregoing specification, a detailed description of an embodiment of the invention has been set down for the purpose of illustration, many variations in the details hereingiven may be made by those skilled in the art without departing from the spirit and scope of the invention.

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Claims (7)

1. A connection for a wedge-type rope socket for an excavating bucket or the like comprising a relatively elongated socket having a larger end and a smaller end, said socket having a tapered passage extending from the larger end to the smaller end, a rope in said passage looped upon itself to provide two lengths of rope in said passage with a loop adjacent said larger socket end, and a relatively elongated wedge apparatus between said two rope lengths, said wedge apparatus having a pair of longitudinally-extending wedge-forming means with an insert means therebetween for relieving pressure on said two rope lengths, said insert means including a plurality of longitudinally tapered block means arranged to slide relative to each other unless constrained against relative longitudinal movement.

2. The connection of claim 1 wherein said tapered block means includes a plurality of blocks each of which has an angle of taper whose tangent is greater than the coefficient of friction between adjacent blocks.

3. The connection of claim 1 or 2 in which said insert means includes a heat destructible housing means for said block means to provide longitudinal constraint.

4. Wedge apparatus for a wedge-type rope socket connection of an excavating bucket comprising a wedge having a small end and larger end and comprising two wedge-forming halves pivotally interconnected adjacent the small wedge end, said wedge halves being equipped with confronting surfaces adjacent the larger wedge end, and an insert adapted for insertion between said confronting surfaces, said insert comprising a plurality of longitudinally tapered blocks adapted to be stacked together between said confronting surfaces, said tapered blocks further being adapted to slide relative to each other in the absence of a longitudinal constraint.

5. The wedge apparatus of claim 4 in which said blocks are constructed of polished steel and tapered with an angle of taper of at least about 12°.

6. A method of manipulating a wedge-type rope socket connection for an excavating bucket or the like comprising providing a relatively elongated socket having a tapered passage extending from one end to the other, installing a multiple-part wedge and rope in said passage wherein said wedge includes outer tapered members and a collapsible insert and, when disassembly of said connection is required, collapsing said insert, said insert including a plurality of stacked tapered blocks slidable with respect to each other upon removal of force sustaining said blocks in a stack, and said step of collapsing said insert includes removal of said sustaining force.

7. A collapsible support for resisting a clamping force comprising three stacked, longitudinally tapered members arranged to slide relative to each other, wedge-forming means including an element adjacent each end member of said stack for applying a compressive load to the stack end members, the middle member of the three stacked members haying an angle of taper relative to each of the adjacent end members, said angle of taper having a tangent greater than the coefficient of friction between adjacent ones of said stacked members, and housing means operably associated with said three members releasably constraining the same against sliding movement longitudinally relative to each other, whereby when said constraining housing means is removed, the middle member of (claim 7 cont'd) said stacked members automatically is ejected relative to said adjacent end members to relieve said compressive load.