AU7405998A - Locking devices - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE

SPECIFICATION

STANDA~RD

PATENT

THE ANI CORPORATION

LTD

Applic ant:.

Inventioni Title: Locking Devices The following statement is a full description of this invention, including the best method of performing it known to mefus:

I

1 i r s i -2- LOCKING DEVICES The present invention relates to locking devices and is particularly concerned with locking devices suitable for securing interengaged components against disengagement.

The locking devices are disengageable to permit the components to be disassembled or relatively displaced.

The present invention has particularly been developed and applied to the field of heavy mechanical engineering in which large components are interengaged on assembly for normal operations, but to permit servicing or selective replacement of worn components, disengagement is periodically required. The invention will be exemplified with reference to large shackles or rigging components for equipment such as dragline buckets for mining operations, 15 but the invention is equally applicable to other types of installations.

Broadly, the present invention concerns a locking mechanism for securing first and second parts in interengagement, the first part being moveable along a first axis to engage in the second part, and one of the parts having a locking cavity for receiving a locking element of the locking mechanism and the other part having a profile including a shoulder extending transverse to the first axis for engagement with a body structure of the locking mechanism whereby on installation of the locking mechanism withdrawal of the first part from the second part is prevented until the locking mechanism is deactivated, the locking mechanism comprising: a body structure comprising first and second body elements; a screw-threaded drive member interconnecting the body elements and adapted to be rotated to drive together or to displace apart the body elements; the body structure having a surface which in use extends transverse to the first axis for engaging the transverse shoulder; 3 a locking element adapted to be located between the body elements; and corresponding ramp surfaces on the locking element and at least one of the body elements such that upon rotation of the drive member to draw the body elements towards one another, the locking element is displaced laterally and transversely of the first axis to engage in the locking cavity whereby the locking mechanism is secured in the second part and prevents withdrawal of the first j 10 part.

Preferably each of the body elements has an interior ramp surface and the locking element has a generally inverted triangular shape with corresponding ramp surfaces Swhereby,- on rotation of the drive member, the locking element;'is displaced laterally at right angles to the axis along which-the drive members extends and this axis is at right angles to the first axis.

It is most advantageous to use an embodiment of the invention in which the locking element is generally diamond 1 20 shaped and preferably each ramp face of the locking element is at a shallow angle to the axis along which the drive member extends.

Most preferably the angle of each ramp face is in the y range 25 to 45 degrees and most preferably is around degrees.

In preferred embodiments the locking member is adapted to be inserted in a nominally rectangular aperture through the second part, the second part accommodating the first part there-through and a corresponding recess or slot in the second part aligns with the zone through which the locking member is inserted.

One important example for use of the present invention is in application to a rigging fitting of the nature of a shackle wherein the second part is generally U-shaped and the first part is a pin extending through the legs of the U-shaped structure and a locking mechanism is provided for 4securing the pin in at least one of the legs.

Significantly the present invention can be applied to an embodiment in which such a pin is of circular crosssection and is rotatable relative to the legs of the shackle.

The screw-threaded drive member can conveniently be in the form of an elongated bolt having a socket or hexagonal style head which is readily driven to either activate the locking mechanism or to deactivate the locking mechanism so that it can be removed, thereby permitting the pin to be removed so that the first and second parts can be serviced or replaced.

In another aspect the invention extends to the combination of the first and second parts interengaged and 15 the locking mechanism provided for securing the parts in interengagement but capable of being disengaged.

Preferably the invention is implemented by having an aperture extending through the second part from one side to the other whereby the locking mechanism can be inserted from either side and removed from either side. The locking mechanism preferably is designed with adequate clearances so that, despite wear or minor distortion in use, it can readily be removed and the mechanism is such that yet a safe and positive locking mechanism resistant to abrasion, vibration, impact and corrosion nevertheless can be an effective and safe form of installation.

Installation and removal of the locking mechanism is accomplished in a preferred embodiment by use of a conventional Allen key, wrench or spanner which provides a convenient form of mechanical advantage and is safe and easily operated typically with a single fitter. This contrasts with previous arrangements used which rely upon driving wedge or locking pins into position and thereby required considerable operator strength or skill but nevertheless involving significant safety issues.

Large scale equipment such as dragline systems are highly capital intensive so that even a minor increase in dow6,n time for servicing has a most substantial adverse economic impact. Known systems rely upon friction e.g.

through wedges or locking pins and periodic checking and driving home the wedges may be necessary. It is believed the present invention can be implemented in safe and reliable systems which can positively retain the parts together and obviate problems associated with the prior art.

At least preferred embodiments can be formed so that the moving parts are enshrouded and inherently well protected even in the harsh environment of a mining operation.

For illustrative purposes only, an embodiment of the invention will now be described with reference to the accompanying drawings, of which.

Figure 1 is a schematic view of a shackle embodying the invention; Figure 2 is an exploded view of the components of the locking mechanism for use in securing the shackle pin in the shackle body shown in Figure 1; Figure 3 is a cross-sectional view along the line Ill- II I shown in Figure 1 and illustrating initial insertion of the assembled locking mechanism into a shackle leg, the locking mechanism being shown in full lines for convenience and the shackle pin being omitted for clarity; Figur' 4 is a cross-sectional view corresponding to Figure 3 but showing the locking mechanism in cross-section when in the locked configuration; Figure :5 is a sectional view along the line V-V of Figure 4; Figure G-is a cross -sectional view along the line VI- VT of Figure 4; Figure 7 is a cross-section along the line VIT-VI of Figure 4; and 6- Figure 8 is an illustration of a typical example of an embodiment to a dragline bucket for a mining machine.

Referring first to Figure 1, a shackle 10 is illustrated and has a generally U-shaped body 13 with legs 16 and 17 each having a circular cross-section bore 24 there-through and in the outer portion terminating in a square cross-section counter bore A shackle pin 18 has a square head 19 in this embodiment, and a circular cross-section body portion and an annular groove 21 near the tip. However, advantageously in using embodiments of the present invention the shackle pin could have a circular cross-section head whereby the whole pin is rotatable and this can be an advantage in permitting even wear around the structure and therefore 15 longer life.

The shackle and pin arrangement is such that the pin can be inserted through either of the legs and the head is H accommodated in the appropriate counter bore.

A transverse nominally rectangular cross-section slot 20 20 is provided through each of the legs and intersects with the counter bore such that when the pin is fully inserted the annular groove 22 aligns with the slot SFigure 8 illustrates how the shackle of Figure 1 could be used for connection of a chain to a drag line bucket.

25 In this case the shackle pin 18 passes through a mounting lug 11 of the bucket 12. Apart from a considerable load.

the pin is subject to vibration and it is preferable to use the option where the whole pin is rotatable in the shackle so that wear can even out and this reduces the risk of bending or distortion of the pin which could cause a severe problem in attempting to remove the pin for replacement after a period of wear.

The locking mechanism is shown in Figure 2 in exploded view and comprises a strip-like body portion 30, a sliding nut portion 31, a drive screw 32 and a diamond shaped locking element 33. Figure 5, 6 and 7 illustrate in -7assembled, locking configuration the cross-sectional views of the locking mechanism. Thus, the body portion 30 has a rectangular cross-section head portion 34 having a downwardly projecting lug 35 and an upstanding abutment portion 36 having an outermost flat shoulder 37, a clearance bore 38 there-through and an inwardly facing ramp surface 39 at about 35 degrees to the horizontal.

SThe locking element 33 is of parallelogram shape and has a pair of ramp surfaces 40 also angled at 35 degrees and upwardly facing secondary ramp surfaces 41 also at degrees to the horizontal. An elongated slot 42 extends through the central region of the locking element 33 to provide a clearance for the screw 32.

The body portion 30 has a tail section 43 in the form 15 of a U-shaped channel in which the nut element 31 is a clearance or sliding fit. The nut element 31 has a threaded bore 44 in which the screw 32 is threadably engaged.

As best shown in Figure 3, the locking mechanism is 20 assembled with the locking element 33 retracted and the nut element 31 displaced to the left but with the tip portion of the screw 32 engaged in the bore 44. The locking element has a flat top 45 aligned with the flat top of the .i nut element 31 and the top of the portion 36. A flat base portion 46 of the locking element is spaced slightly above the base of the U-shaped channel portion. The locking mechanism has been inserted from the right until the lug engages in a corresponding recess 47 in the outer face of the leg of the shackle. However, a corresponding lug is also provided on the left hand side so that equally the locking mechanism could be inserted from the left.

For clarity Figure 3 omits the locking pin which in practice would be first inserted so that the annular recess 21 of the locking pin accommodates the central portion of the body When the screw 32 is rotated clockwise, the head is in abutment with the shoulder 37 and the nut element 31 is drawn to the right as shown in Figure 3 thereby causing locking element 33 to be displaced along an upwardly inclined track and parallel to the ramp surface 39. The clearances. In practice it would be preferred for the dimensions to be such that on fully tightening the screw 32 the locking element is into hard abutment with the respective inclined surfaces.

For the purpose of accommodating the locking element 33 in locking engagement, the leg of the shackle has a recess 50 comprising a flat top 51 and angled surfaces 52 15 and 53 which are at about 35 degrees to the horizontal.

Claims (16)

1- A locking mechanism for securing first and second parts in interengagement, the first part being moveable along a first axis to engage in the second part, and one of the parts having a locking cavity for receiving a locking element of the locking mechanism and the other part having a profile including a shoulder extending transverse to the first axis for engagement with a body structure of the locking mechanism whereby on installation of the locking mechanism withdrawal of the first part from the second part is prevented until the locking mechanism is deactivated, the locking mechanism comprising: (Ca) a body structure comprising first and second body elements; a screw-threaded drive member interconnecting the body elements and adapted to be rotated to drive together or to displace apart the body elements; the body structure having a surface which in use S 20 extends transverse to the first axis for engaging the transverse shoulder: d) a locking element adapted to be located between the body elements; and corresponding ramp surfaces on the locking element and at least one of the body elements such that upon rotation of the drive member to draw the body elements towards one another, the locking element is disolaced Slaterally and transversely of the first axis to engage in the locking cavity whereby the locking mechanism is secured in the second part and prevents withdrawal of the first part.

2. A locking mechanism as defined in claim 1 and wherein each of the body elements has an interior ramo surface and the locking element has a generally inverted triangular shape with corresponding ra:- surfaces whereb on rotation of the drive meoer, the locking element s L ~U CUI-DI UCI--- C~LIIIIVI~ I~~ displaced laterally at right angles to the axis along which the drive members extends and this axis is at right angles to the first axis.

3. A locking mechanism as defined in claim 1 or claim 2 and wherein the locking element is generally diamond shaped.

4. A locking mechanism as defined in claim 3 and wherein each ramp face of the locking element is at a shallow angle to the axis along which the drive member extends.

A locking mechanism as defined in claim 4 and wherein the angle of each ramp face is in the range 25 to degrees.

6. A locking mechanism as defined in claim 5, and .t 15 wherein the angle of each ramp face is about 350 to the A. axis.

7. A locking mechanism as defined in any one of the preceding claims and wherein the locking member is adapted to be inserted in a nominally rectangular aperture through the second part, the second part accommodating the first part there-through and a corresponding recess or slot in the second part aligns with the zone through which the locking member is inserted.

8. A locking mechanism as defined in claim 7 and adapted for locking the components of a shackle having a U- shaped body with legs between which a shackle pin is secured, the U-shaped body providing said second part and the pin providing said first part.

9. A locking mechanism as defined in claim 9 and wherein the pin is of circular cross-section and is rotatable relative to the legs of the shackle.

A locking mechanism as defined in any one of the preceding claims and wherein the screw-threaded member is in the form of an elongated bolt having a socket or hexagonal style head which is readily driven to either activate the locking mechanism or to deactivate the locking mechanism so that it can be removed, thereby permitting the pin to be removed so that the first and second parts can be serviced or replaced.

11. A locking mechanism as defined in any one of the preceding claims and wherein the parts of the mechanism adapted to move are enshrouded.

12. A locking mechanism as defined in any one of the preceding claims and wherein the locking mechanism is adapted to be applied to a shackle type rigging fitting for a relatively large machine.

13. A locking mechanism substantially as herein described with reference to the accompanying drawings.

14. In combination, a locking mechanism as claimed in any one of the preceding claims and the first and second 15 parts adapted to be interengaged and removable secured :I together by the locking mechanism.

A combination as defined in claim 14 and wherein there is an aperture extending through the second part from one side to the other whereby the locking mechanism can be 20 inserted from either side and removed from either side.

16. A combination as defined in claim 15 and wherein the locking mechanism has clearances clearances so that, despite wear or minor distortion in use, it can readily be removed and the. mechanism is such that yet a safe and positive locking mechanism resistant to abrasion, vibration, impact and corrosion is provided DATED this ist day of July 1998 THE ANI CORPORATION LIMITED By their Patent Attorneys GRIFFITH HACK