AU2008100292A4

AU2008100292A4 - Improvements in locking pins

Info

Publication number: AU2008100292A4
Application number: AU2008100292A
Authority: AU
Inventors: Thomas Anthony Meyers
Original assignee: CQMS Pty Ltd
Current assignee: CQMS Pty Ltd
Priority date: 2004-11-05
Filing date: 2008-04-03
Publication date: 2008-05-29
Anticipated expiration: 2013-10-31
Also published as: AU2008100292B4

Description

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m 0, P/00/012 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: "IMPROVEMENTS IN LOCKING PINS" The following statement is a full description of this invention, including the best method of performing it known to me/us:

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TITLE

"IMPROVEMENTS IN LOCKING PINS" FIELD OF THE INVENTION This invention is concerned with improvements in releasably connectable locking pins in coupling mechanisms.

_The invention is concerned particularly, although not 00 Sexclusively, in releasably connectable locking pins for shackles and the like in earthworking equipment.

BACKGROUND OF THE INVENTION Releasably engageable locking pins are employed in a variety of engineering applications and in relation to earthworking equipment. Such locking pins may be utilized in rigid interconnection of boom elements of dragline excavators, pivotal connection of a boom to a chassis or frame, shackle pins for chains and wire ropes, dragline rigging systems and the like.

In nearly all engineering applications and, in particular, in the field of earthworking equipment, it is necessary to secure a retaining pin with a positive lock mechanism so that it does not become detached during operation. At the same time, there is a requirement that such locking pins be quickly and easily disconnected when required for maintenance and repair purposes. Typically, a releasable locking pin comprises a shaft which engages in aligned apertures in spaced cheeks or dclevises associated with a coupling member such as a shackle and an enlarged head on one end of the pin engages on an outer surface of one of the cheeks or dclevises. The free end of the pin often extends outwardly from an outer surface of the opposite 00 2 2 Scheek or clevis and a locking or engaging mechanism may be secured to the free end of the pin to prevent its withdrawal from the spaced cheeks or dclevises of the coupling member.

SUnited States Patent 4,476,673 describes a simple shackle pin locking mechanism in the form of a resilient clip engageable between a shackle clevis and an enlarged pin head formed in the shape of an annulus 00o with a central aperture, the central axis of which apertures lies in a plane at right angles to a rotational axis of the pin. This clip locking mechanism is considered to be unsuitable in an earthworking environment due to the ease of dislodgement of the locking clip.

Other more complicated pin locking mechanisms are described in United States Patents 5,433,547, 4,914,903, 4,221,252, 3,811,270, 2,214,912, and Re. 34046 which required deformable keeper mechanisms or resiliently biased keepers.

United States Patent 5,597,260 describes a locking pin with radially extending projections on a free end thereof, the projections extending through a pair of flange plates having alignable apertures complementary to the cross-sectional shape of the pin end with the radial projections. By axially misaligning the apertures of respective flange plates and then bolting the plates together, a secure locking mechanism is effected.

United States Patent 4,337,614 describes a similar system to that of United States Patent 5,597,260 with a single apertured plate secured against rotation by a pin anchored on an inner face of the plate by a snap ring mounted in a slot in a specially contoured face of the shackle clevis.

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Generally speaking, most of the prior art pin locking assemblies are satisfactory for their intended purpose however, in the case of many of 0 these systems, the ease of disengagement of a locking pin has been sacrificed in the interest of obtaining a positive locking mechanism. In other more complicated mechanisms, the specially fabricated components, machined surfaces and the like have given rise to very expensive shackle/pin 0O Scombinations unsuited to interchangeability of components.

Another serious disadvantage associated with prior art shackle pin retention systems is that the engagement mechanism which prevents relative rotation between, say, a threaded shaft and a nut or a cotter pin or a deformable keeper, is exposed to ingress of fine particles of earth which tightly pack around the retention mechanism to resist pin removal. Many such systems then require removal with a large hammer or the like to dislodge the compacted soil and otherwise to free the retaining mechanism.

The use of impact devices such as hammers or the like in a field situation is considered dangerous due to the risk of injury from high velocity metal fragments which can break off during impact, or the risk of injury from a misdirected or glancing blow of the hammer.

OBJECT OF THE INVENTION Accordingly, it is an object of the present invention to overcome or ameliorate one or more of the disadvantages associated with prior art pin locking systems and otherwise to provide consumers with a greater choice of pin locking systems.

SUMMARY OF THE INVENTION OO 00 4

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According to one aspect of the invention there is provided a heavy duty locking pin assembly comprising:- O a shaft member having a head formation located on an end thereof, said shaft member having a non-circular cross-sectional shape; N 5 a spigot portion located on an end of said shaft member opposing 0 said head formation, said spigot portion having one or more slots, each of 00 said one or more slots having a leg portion terminating at a blind end, said blind end having an undercut region; a retaining member releasably securable on said spigot portion, said retaining member having a central recess adapted to receive said spigot portion and one or more pins projecting radially within said central recess, each of said one or more pins locatable within a respective slot of said spigot portion; and a resiliently deformable member locatable on said spigot portion substantially between said shaft and said one or more slots of said spigot portion; wherein, said resiliently deformable member is compressible to allow passage of each of said one or more pins of said retaining member in a respective slot of said spigot member from said leg portion to said blind end, said resiliently deformable member being resiliently recoverable to thereby urge each of said pins of said retaining member into said undercut region of said blind end of a respective slot to releasably secure said retaining member on said spigot portion.

Further features of the invention will become apparent from the 00 N following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more readily understood and put into practical effect, reference will now be made to embodiments N 5 illustrated in the accompanying drawings in which:- FIG. 1 shows an exploded view of a locking pin assembly; 00O FIG. 2 shows a cross-sectional view through the retaining member of FIG. 1; FIG. 3 shows an inverted isometric view of the retaining member of FIG. 1; FIG. 4 shows a side elevational view of the shaft member of FIG. 1; FIG. 5 shows an end elevational view of the shaft member of FIG. 1; FIG. 6 shows schematically a part cross-sectional view of the locking pin assembly of FIG. 1 mounted in the dclevises of a shackle; FIG. 7 shows a partial cross-sectional view of an alternative embodiment to the assembly of FIG. 6; FIG. 8 shows an exploded view of an alternative embodiment to the assembly of FIG. 1; and FIG. 9 shows a cross-sectional view through the retaining member of FIG. 8.

Like reference numerals have been employed for like features in the drawings for the sake of simplicity.

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00 6 SThroughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as O "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

DETAILED DESCRIPTION OF THE DRAWINGS 00oO In FIG. 1, the locking pin assembly 1 comprises a shaft member 2 having an enlarged head 3 on one end thereof. Head 3 is generally circular in cross-section whereas shaft member 2 has a generally "D"-shaped cross-section as shown in FIG. On the free end of shaft member 2 is a generally cylindrical spigot 4 having formed therein circumferentially spaced slots 5 in the form of an inverted shape.

A resiliently deformable member 6 comprising an apertured disk of weather resistant neoprene rubber, polyurethane, silicone or other suitable polymeric material is locatable on an unslotted land portion 4a of spigot 4. An annular steel washer 7 is locatable over spigot 4 and forms a bearing member to distribute compressive forces applied by the retaining member 8 to resiliently deformable member 6 and otherwise protects member 6 against tearing or damage as retaining member 8 rotates with member 6 under compression. Retaining member 8 includes a hex headed cap 9, the purpose of which will be described later.

FIG. 2 shows a cross-sectional view of retaining member 8 of FIG. 1.

00 7 SIn FIG. 2, retaining member 8 is formed with a hollow central recess 10 having a generally cylindrical inner wall 11 from which pins 12 project radially inwardly. A circumferential skirt 8a forms a locating recess 8b for steel washer 7.

C 5 An inverted isometric view of retaining member 8 is shown in FIG. 3 wherein it can be seen that there are three equidistantly spaced pins 00oO 12.

FIG. 4 shows a side elevational view of the shaft member of FIG. 1 in which the configuration of slots 5 is more clearly shown.

The mouth or opening 16 of each slot 5 is located at the free end 17 of shaft member 2 and the "leg" portion 18 of each shaped slot is inclined relative to a longitudinal axis 19 of shaft member 2 such that when a pin 12 is located therein and a retaining member is rotated clockwise relative to shaft member 2, an inner edge 20 of slot 5 acts as a cam to move the retaining member in the direction of enlarged head portion 3 against a restoring force applied by resilient member 6 as shown in FIG. 1. With continued rotation, pins 12 move over respective cam surfaces 20 until they reach respective zeniths 21 on the cam surfaces 20 and the pins ride over zeniths 21 to locate in the blind ends 22 of slots 5 in the manner of a bayonet-type fitting. Pins 12 are urged into the undercut region 23 of blind ends 22 under a restoring influence applied by compressed resilient member 6.

In order to disengage retaining member 8 from shaft member 2, a hex socket of appropriate size is coupled to a socket bar and retaining 00 8 8 member 8 is rotated anticlockwise. During rotation, inner edges 24 of blind ends 22 of slots 5 also act as cam surfaces on respective pins 12 of retaining 0 member 8 to urge retaining member 8 into compression against resilient member 6 while pins 12 move over zeniths 21 and thence into respective leg C 5 portions 18 of slots FIG. 5 is an end elevational view of the shaft member 2 of 00 FIG. 4.

(-i In this illustration, the configuration of the three slots 5 can be more clearly seen and also the D-shaped cross-section of shaft member 2.

The D-shaped cross-section of shaft member 2 is locatable in aligned apertures of spaced cheek plates or dclevises of a coupling member such as a shackle whereby rotation of shaft member 2 is presented during connection or disconnection of a retaining member thereto.

FIG. 6 shows a partial cross-sectional view of a coupling member 25 incorporating a locking pin assembly 1. Shaft member 2 extends via apertures 26 of complementary cross-sectional shape in the spaced dclevises 27 of a shackle or the like As can be seen in FIG. 6, when retaining member 8 is connected to shaft member 2, resilient member 6 is in compression due to the bayonet-type coupling therebetween.

With resilient member 6 in a compressed state, an effective soil and moisture proof seal is formed about the bayonet type coupling by engagement between the free end of side wall 28 of retaining member 8 (and/or washer 7) and an outer face 29 of resilient member 6. Similarly, an 00 9 C inner wall (not shown) of generally annular resilient member 6 is compressed against land portion 4a (shown in FIG. 1) of spigot 4 formed on the end of shaft member 2.

As illustrated in FIG. 7, in an alternative embodiment to that c 5 shown in FIG 1, washer 7 may be located over land 4 on shaft member 2 to abut shoulder 2a thereon. Resilient seal member 6 is then sandwiched 00oo between washer 7 and the inner face 8b of retaining member 8 when the retaining member 8 is engaged in a coupling such as a shackle or the like.

Washer 7 thus provides an increased bearing face against which resilient seal member 6 is compressible.

Also shown in FIG. 7 is an alternative mechanism to prevent shaft 2 from rotation within the aligned apertures 26 in the dclevises 27 of shackle or the like 28. In this embodiment, head 3 includes a flat or like abutment surface 3a which engages against a shouldered abutment 30 on clevis 27 to prevent relative rotation between shaft 2 and shackle or the like 28.

FIG. 8 illustrates an alternative configuration of a locking pin assembly to that shown in FIG. 1.

In FIG. 8, the end of shaft 2 is formed with a cylindrical spigot 4 from which are circumferentially spaced radially extending pins 12. Retaining member 8 includes a hexagonal socket recess 31 to locate an Allan key or similar hexagonal driving spigot for rotation of retaining member 8.

FIG. 9 shows a cross-sectional view through the retaining member 8 of FIG. 8.

00 SIn FIG. 9, the inner wall surface 11 of retaining member 8 is formed with shaped slots 5 in the form of inverted shape spaced Cc, 0 circumferentially around inner wall surface 11. Like the arrangement of FIG. 1, the pins 12 and slots 5 form a spigot and socket bayonet-type c 5 coupling.

_In use it has been found that locking pin assemblies according 00 to the invention are robust and capable of withstanding harsh treatment in earthworking environments such as excavator rigging shackles. In particular, even after prolonged use, the locking pin assemblies are easily connected and disconnected with a conventional socket and torque bar by a single operator as the bayonet type coupling is sealed against the ingress of soil and moisture which otherwise tends to "freeze up" conventional locking pin assemblies. This ease of connection and disconnection obviates the need for the use of a hammer which otherwise would be required with many prior art shackle pins and thereby reduces the safety risks associated with such systems.

It readily will be apparent to a person skilled in the art that many modifications and variations may be made to the invention without departing from the spirit and scope thereof.

For example, although the embodiment illustrated comprises a bayonet-type coupling having three pins locatable in respective slots, it is considered that one or more pin/slot combinations would be effective, however two or more pin/slot combinations would provide a more even load distribution between the components of the bayonet-type coupling.

0 11 0 c Similarly, while the embodiment illustrated shows pin slots formed on shaft member 2 and pins located in retaining member 8, the pins 0 of the bayonet-type coupling could be formed on shaft member 2 for releasable engagement with corresponding slots formed in retaining member 8.

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Claims

1. A heavy duty locking pin assembly comprising: a shaft member having a head formation located on an end thereof, said shaft member having a non-circular cross-sectional shape; C 5 a spigot portion located on an end of said shaft member opposing said head formation, said spigot portion having one or more slots, each of 00 oo said one or more slots having a leg portion terminating at a blind end, said blind end having an undercut region; a retaining member releasably securable on said spigot portion, said retaining member having a central recess adapted to receive said spigot portion and one or more pins projecting radially within said central recess, each of said one or more pins locatable within a respective slot of said spigot portion; and a resiliently deformable member locatable on said spigot portion substantially between said shaft and said one or more slots of said spigot portion; wherein, said resiliently deformable member is compressible to allow passage of each of said one or more pins of said retaining member in a respective slot of said spigot member from said leg portion to said blind end, said resiliently deformable member being resiliently recoverable to thereby urge each of said pins of said retaining member into said undercut region of said blind end of a respective slot to releasably secure said retaining member on said spigot portion. 00

2. The heavy duty locking pin assembly of claim 1, wherein said resiliently e deformable member is locatable on said spigot portion such that a face of Ssaid resiliently deformable member opposes and engages an inner face of said retaining member and an opposing face of said resiliently deformable member opposes and engages a face of a washer located on said spigot 0portion, an opposing face of said washer opposing and engaging a shoulder 00 0of said shaft member.

3. The heavy duty locking pin assembly of claim 1, wherein said resiliently deformable member is in the form of a disc having an aperture extending therethrough, said aperture adapted to receive said spigot portion.

4. The heavy duty locking pin assembly of claim 1, wherein said shaft member comprises at least one longitudinally extending planar surface. A heavy duty locking pin assembly as substantially herein described with reference to the Figures.