GB2088520A

GB2088520A - Chain engaging devices

Info

Publication number: GB2088520A
Application number: GB8136444A
Authority: GB
Original assignee: Parsons Controls Ltd
Current assignee: Parsons Controls Ltd
Priority date: 1980-12-03
Filing date: 1981-12-03
Publication date: 1982-06-09
Also published as: GB2088520B

Abstract

A chain engaging device has a clevis end 4 to permit of attachment to an eye 8 of a standing length of wire rope 10 or chain. A main body portion is formed with a longitudinal surface groove 14 and a lobed jaw portion 16 to accommodate links 24 and 32 of a length of chain 26. The link 32 is retained on seating faces formed in the lobed jaw portion by the action of a spring-biassed plunger 52 engaging a peripheral portion of the link 24. Movement of the plunger against the spring bias brings a circumferential groove on the plunger into register with the link 24 thereby permitting movement of the link 24 past the plunger and disengagement from - or engagement into - the lobed jaw portion 16. <IMAGE>

Description

SPECIFICATION Improvements in and relating to chain engaging devices This invention relates to chain engaging devices and, more particularly, to a shortening clutch for engagement with a link in a full length of chain in order to shorten the effective length of the fall.

According to the invention there is provided a chain engaging device including a body portion formed with an end fitting for attachment to a standing length of chain or wire rope and, remote from the end filling, a lobed jaw portion profiled to receive first and second interlinked links of a fall length of chain with the second link supporting the first link extending in a gap in the lobed jaw portion and detent means arranged to retain the first and second links in the lobed jaw portion movable between a first position in which the detent means co-act with the first link to retain the first and second links in the lobed jaw portion and a second position in which the first and second links are movable in the lobed jaw portion.

The invention will now be described, by way of example, with reference to the accompanying drawings in which Figure 7 is a front elevation of a chain engaging device, or shortening clutch, mounted on a wire rope but without chain engaged; Figure 2 is a side elevation of the shortening clutch, indicating links of an engaged chain, with an upper portion of the clutch shown in section; and Figure 3 is a view of a retaining pin, to an enlarged scale.

The shortening clutch 2 is formed with a clevis end portion 4 provided with a load pin 6 spanning the clevis to permit the attachment to an eye 8 of a standing length of wire rope 10. A main body portion 12 of the shortening clutch is formed with a longitudinal surface groove 14 extending from the clevis end portion 4 toward a lobed jaw portion 16, the lobes 18,20 of the lobed jaw portion being spaced apartfrom a gap 22 forming a continuation of the surface groove. The surface groove and the gap are profiled to accommodate a link 24 of a fall portion 26 of chain and the inner faces 28,30 of the lobed jaw portion are profiled to accommodate an immediately interlinked link 32 of the fall portion of chain toward a free end of the fall portion.Outer faces 34,36 of the lobed jaw portion remote from the clevis end portion are profiled to accommodate a link 38 in the fall portion immediately interlinked with the link 24 accommodated in the gap and remote from the free end of the fall portion.

The main body portion 12 is drilled adjacent the lobes 18,20 from an outside face adjacent one lobe to an outside face adjacent the other lob to form a stepped bore 40 exteding perpendicular to the surface groove 14, intersecting both the surface groove and the gap 22 at a junction region. The stepped bore has a first short section 42 of narrow diameter adjacent one side face emerging at a base portion of an arcuate section groove 44 in the side face, an intermediate section 46 and a second short section 48 of wider diameter adjacent the other side face. The second short section is threaded to receive a grub screw 50.A plunger 52 is formed with a hollow, end portion 54, a central portion 56 formed with an arcuate cross-section circumferential groove 58 and a lesser diameter spindle 60 which are respectively sliding fits within the intermediate section 46 and the first section 42 of the stepped bore. A coiled compression spring 62 is seated in the hollow end portion 56 of the plunger and extends outwardly from the plunger. The plunger 52 and coiled compression spring 62 is assembled into the stepped bore 40 of the main body portion with the spindle 60 extending through the first section 42 of the stepped bore and the arcuate section groove 44 to project beyond the surface of the associated side face 18.

The coiled spring 62 is then compressed and the grub screw 50 screwed into the threaded second section 48 of the stepped bore such that an annular shoulder 64 on the plunger is urged into abutment with the step 66 in the bore between the intermediate section 46 and the first section 42. In this position the circumferential groove 58 in the plunger is positioned within a portion of the stepped bore 40 within the associated lobe 18 and a portion at the right circular cylindrical surface of the plunger is positioned at the intersection with the gap 22 between the lobes. The circumferential groove 58 on the plunger is brought into register with the gap by decreasing the spindle 62 to move the plunger axially.

In operation, to engage the shortening clutch with the link 24 of chain, the spindle 60 on the plunger 52 is depressed to bring the circumferential groove 58 into register wth the gap 22 whereupon the link 24 may be inserted along the surface groove 14 and into the gap 22 between the lobes 18, 20 with the link 32 toward the free end sliding into engagement with and seating on the profiled inner faces 28,30 of the lobed jaw portion to support the link 24. The spindle 60 on the plunger 52 is then released and the coiled spring 62 urges the plunger axially of the bore to position a right circular cylindrical portion of the plunger at the intersection of the gap 22 and the surface groove 14.The dimensions of the profiled inner faces 28,30 and their position relative to the stepped bore 40 are such that movement of the link 24 out of the gap is prevented by abutment against the right circular cylindrical surface of the plunger, thereby achieving retention of the link 24 between the lobed jaws of the shortening clutch.

To remove the fall portion 26 of chain from the shortening clutch, the spindle 60 is depressed to move the circumferential grooves 58 on the plunger 52 into register with the cap 22 between the lobes 18, 20 whereupon the said links 24,32 may be disengaged from the jaws, the profiled outer faces 34,36 of the lobed jaw portion accommodating the link 38 in the fall portion 26 to permit of sufficient movement of the links to clear the jaws.

It will be appreciated that retention of the link 24 in the lobed jaw portion 16 may be achieved utilising other forms of detent means such as, for example, a spring biassed, pivoted, catch positioned in an extension of the gap 22 or a sliding bolt positioned in the longitudinal surface groove 14.

Claims

1. A chain engaging device including a body portion formed with an end fitting for attachment to a standing length of chain or wire rope and, remote from the end fitting, a lobed jaw portion profiled to receive first and second supporting the first link extending in a gap in the loaded jaw portion and detent means arranged to retain the first and second links in the lobed jaw portion movable between a first position in which the detent means co-act with the first link to retain the first and second links in the lobed jaw portion and a second position in which the first and second links are movable in the lobed jaw portion.

2. A chain engaging device as claimed in Claim 1, wherein the detent means is resiliently biassed toward the first position.

3. A chain engaging device as claimed in Claim 1 or Claim 2, wherein the detent means includes a cylindrical plunger axially movable in a bore in the body portion intersecting the gap in the lobed jaw portion.

4. A chain engaging device as claimed in Claim 3, wherein the cylindrical plunger is formed with a circumferentially extending groove registerable in the second position of the plunger with the gap to permit of movement of the first and second links in the lobed jaw portion.

5. A chain engaging device as claimed in Claim 3 or Claim 4, wherein the cylindrical plunger is formed with a spindle extension extending from the body portion of the device and depressableto effect movement of the plunger from the first position to the second position.

6. A chain engaging device as claimed in Claim 5, wherein the spindle extends into a shallow recess formed in the body portion of the device.

7. A chain engaging device as claimed in Claim 5 or Claim 6, wherein the bore for the cylindrical plunger is of stepped form and an end portion of the bore remote from the end portion accommodating the spindle extension is threaded to receive a grub screw and a coiled compression spring is positioned intermediate the grub screw and the cylindrical plunger.

8. A chain engaging device as claimed in Claim 7, wherein an end portion of the cylindrical plunger remote from the spindle extension is hollow and open ended to accommodate a portion of the coiled compression spring.

9. A chain engaging device arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying draw ings.