Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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.
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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.
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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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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
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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
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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
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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
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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
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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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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,
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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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