GB2301576A

GB2301576A - A Fastening arrangement

Info

Publication number: GB2301576A
Application number: GB9510922A
Authority: GB
Inventors: Nicholas Gordon Collins; Geoffrey Taylor
Original assignee: Arjo Ltd
Current assignee: Arjo Ltd
Priority date: 1995-05-31
Filing date: 1995-05-31
Publication date: 1996-12-11
Anticipated expiration: 2015-05-31
Also published as: GB9510922D0; WO1996038118A1; AU5159196A; GB2301576B

Abstract

A fastening arrangement for releasably fastening an invalid suspension device (not shown) to a lifting arm 10 of a hoist, comprises a sleeve-like member 12 which is slidable on the lifting arm and which has means 26 to which the suspension device is attached or attachable, releasable locking means 13, 14 for releasably locking the sleeve-like member in a position in which it is fully engaged with the lifting arm, and complimentary means 16, 23 and 17, 25 on the sleeve-like member and lifting arm for forcing the sleeve-like member to be tilted relative to the lifting arm in order that it can be removed from the lifting arm. Preferably the releasable fastening is a spring-pressed pin 13 engaging in a hole 24 in the sleeve 12 and a stud 25 on the sleeve engaging in a hole 17 on the arm. The pin is released by button 15. Preferably an arm cross-pin 16 coacts with extended recess 22 and inclined grooves 23 to allow movement to release arm end from sleeve socket 20 when the fastening is released and to tilt the sleeve for removal from the arm. The arrangement allows a number of suspension devices (Figs 6 and 7) to be used with the same arm.

Description

FASTENING ARRANGEMENT This invention relates to a fastening arrangement for releasably fastening a suspension device to a lifting arm of a hoist, more particularly but not exclusively an invalid hoist.

Invalid hoists often comprise an upstanding support column or mast, a lifting arm which projects from the support column and which is movable along the support column by mechanical or power operated means to raise or lower the lifting arm and a suspension device, such as a sling hanger or stretcher support, which is permanently fixed to the lifting arm. The support column is commonly mounted on a mobile chassis. In many cases, the hoist is designed to serve only one purpose and in these cases the suspension device is not interchangeable. In some cases, the lifting arm together with the suspension device is designed to be removable so that it can be interchanged with another lifting arm provided with a different type of suspension device. The need to supply an additional lifting arm with each suspension device adds to the cost of the hoist.

The present invention seeks to provide a fastening device for releasably fastening a suspension device to a lifting arm so that different types of suspension devices can be used without the need to supply additional lifting arms.

According to a first aspect of the present invention there is provided a fastening arrangement for releasably fastening a suspension device to a lifting arm of a hoist, comprising a sleeve-like member which is slidable on the lifting arm and which has means to which a suspension device is attached or is attachable, releasable locking means for releasably locking the sleeve-like member in a position in which it is fully engaged with the lifting arm, and complementary means on the sleeve-like member and lifting arm for forcing the sleeve-like member to be tilted relative to the lifting arm in order that it can be removed from the lifting arm.

Preferably, the lifting arm is of circular outer cross-section and the sleevelike member has a bore of circular cross-section and means are provided for preventing the sleeve-like member swivelling relative to the lifting arm about the axis of the sleeve-like member.

Preferably, the complementary means comprises two opposed projections on the lifting arm (or the sleeve-like member) and a pair of grooves in the inner wall of the sleeve (or in the outer wall of the lifting arm) for co-operating respectively with the two projections, the grooves being inclined to the longitudinal axis of the sleevelike member (or the lifting arm). In this case, the inner ends of the grooves may communicate with slots which extend parallel to the longitudinal axis of the sleeve-like member (or the lifting arm) and in which the projections engage as the sleeve-like member reaches a position in which it is fully engaged with the lifting arm.

Preferably, the sleeve-like member has a first sleeve at its outer end for receiving the free end of the lifting arm and a second oblique sleeve at its inner end, the first sleeve being joined to that portion of the second sleeve nearest to the first sleeve and there being an opening between the first sleeve and that portion of the second sleeve furthest from the first sleeve which opening receives the free end of the lifting arm after the latter has been removed from the first sleeve and as the sleevelike member is tilted relative to the lifting arm. In this case, preferably, the portion of the second sleeve nearest the first sleeve is uppermost in use and the top of the second sleeve is axially offset from the bottom of the second sleeve.

Preferably, the releasable locking means comprises a spring-loaded plunger which is provided on the lifting arm and which is engageable in a hole in the sleevelike member when the sleeve-like member is in a position in which it is fully engaged with the lifting arm. In this case, the releasable locking means may also comprise a release button for moving the plunger to a release position against its spring loading.

The sleeve-like member may also include a pin projecting into its bore for locating in a hole in the lifting arm when the sleeve-like member is fully engaged with the lifting arm.

Preferably, the sleeve-like member has support means at its outer end for supporting a suspension device, e.g. a sling hanger. Advantageously, the support means supports the suspension device for swivellable movement about a vertical or substantially vertical axis.

According to a second aspect of the invention there is provided a hoist having a lifting arm and a fastening arrangement according to the first aspect of the invention.

The hoist preferably also includes an upstanding column supporting the lifting arm. The upstanding column may be telescopic to raise and lower the lifting arm or may include means for raising and lowering the lifting arm relative to the support column. The column is typically supported on a mobile chassis.

The invention will now be more particularly described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view partly in section of a lifting arm of a hoist including part of one embodiment of a fastening arrangement according to the invention, Figure 2 is a side view partly in section of the free end of the lifting arm of Figure 1 on an enlarged scale, Figure 3 an end view of the free end of the lifting arm, Figure 4 is a side view of a sleeve-like member forming the other part of the fastening arrangement, Figure 5 is a view of the inner end of the sleeve-like part of Figure 4, and Figures 6 and 7 are side views of two sleeve-like members supporting different suspension devices.

Referring to the drawings, there is shown therein a lifting arm 10 of a hoist, more particularly but not exclusively an invalid hoist, and a suspension device 11 such as a stretcher support or sling hanger (see Figures 6 and 7) supported by a sleeve-like member 12.

The lifting arm 10 is supported by an upstanding column (not shown) which is mounted on a mobile chassis. The upstanding column may be telescopic in which case the lifting arm is fixed to the upper end of the upper part of the column.

Alternatively, the lifting arm may be raised and lowered along the column by a motorised or mechanical mechanism.

The lifting arm 10 is in the shape of a swan neck and is of tubular construction and circular cross-section.

A latch pin 13 is urged to project through a hole in the top of the lifting arm by a U-shaped spring 14 mounted within the bore of the lifting arm 10. A release button 15 is secured to the spring 14 on that side of the latch pin 13 remote from the free end of the lifting arm 10 and this release button 15 projects through a further hole in the top of the lifting arm 10 for a purpose which will be explained hereinafter.

A transverse pin 16 extends diametrically through the lifting arm 10 so as to project horizontally from opposite sides thereof and is located on that side of the latch pin 13 nearer to the free end of the lifting arm 10.

A hole 17 is provided in the bottom of the lifting arm for a purpose which will become apparent.

The sleeve-like member 12 comprises a first sleeve 18 at its outer end, a second oblique sleeve 19 at its inner end and a semi-cylindrical part 20 joining the first and second sleeves 18 and 19, respectively. The first and second sleeves 18 and 19 have right cylindrical bores having diameters slightly larger than the diameter of the lifting arm 10 so that the sleeve-like member 12 is a loose fit on the lifting arm 10.

The oblique sleeve 19 is slanted at an angle of about 600 to a plane normal to the axis of the sleeve-like member 12 and is dimensioned such that the top of the bore of the sleeve 19 is axially offset from the bottom of the bore. This makes it possible for the sleeve-like member 12 to tilt relative to lifting arm 10 through a significant angle, typically 100 or more, when the free end of the lifting arm is removed from the first sleeve 18.

The semi-cylindrical part 20 joins the first sleeve 18 to that part of the second sleeve 19 closest to the first sleeve 18 leaving an opening 21 of trapezoidal shape (as viewed from each side of the sleeve-like member 12) bounded by a semicircular face of the first sleeve 18, a semi-elliptical face of the second sleeve 19 and the lower face of the semi-cylindrical part 20.

An elongate recess 22 extending parallel to the longitudinal extent of the member 12 is formed in each free edge of the semi-cylindrical part 20 adjacent to the second sleeve 19 and a groove 23 is formed in the wall of the bore of the second sleeve 19 on each of two opposite sides of said bore. The recesses 22 communicate with the opening 21 and the grooves 23 are inclined upwards towards the outer or rearmost end of the sleeve 19 at an angle which is typically about 100.

An aperture 24 is provided in the top of the sleeve-like member 12 adjacent to its rear end to receive the spring-loaded latch pin 13 when the sleeve-like member 12 is fully engaged with the lifting arm 10 and a pin 25 projects into the bore of the sleeve 19 at the bottom thereof for location in the hole 17 also when the sleeve-like member 12 is fully engaged with the lifting arm 10.

A boss 26 having a vertically extending through bore 27 is secured, such as by welding, to the outer end of the sleeve-like member 12 for swivellably supporting the suspension device 11.

When the sleeve-like member 12 is fully engaged with the lifting arm 10, the latch pin 13 holds the sleeve-like member 12 firmly in place. The transverse pin 16 engages in the recesses 22 and the pin 25 is located in the hole 17. The free end of the lifting arm 12 extends into the sleeve 18.

In order to remove the sleeve-like member 12 from the lifting arm 10, the release button 15 is depressed. This compresses the spring 14 and the latch pin 13 disengages from the hole 24 in the sleeve-like member 12. The sleeve-like member 12 is then slid forwardly along the lifting arm 10 to bring the pin 16 to the rear ends of the recesses 22 and to remove the sleeve 18 from the free end of the lifting arm 12.

The sleeve-like member 12 must then be tilted upwards at an angle of about 100 to the horizontal to release the pin 25 from the hole 17 and to bring the inclined grooves 23 in the sleeve 19 into parallel relationship with the axis of the lifting arm 10. The sleeve-like member 12 can then be slid further forwardly with the ends of the transverse pin 16 passing along the grooves 23 to remove to sleeve-like member 12 from the lifting arm 10.

When the sleeve-like member 12 is tilted as aforesaid this will be clearly apparent to a user thus warning the user that the sleeve-like member is not properly engaged.

The hoist can be supplied with a plurality of different suspension devices attached to identical sleeve-like members and these can be interchanged at will.

Typical examples of two such suspension devices are shown in Figures 6 and 7. The suspension device shown in figure 6 is a support frame 24 for a stretcher assembly swivellable about a vertical axis and the suspension device shown in Figure 7 is a four point sling hanger having a hanger support 30 swivellable about a vertical axis and a sling hanger 31 connected to the hanger support for pivotable movement about a horizontal axis.

Claims

1. A fastening arrangement for releasably fastening a suspension device to a lifting arm of a hoist, comprising a sleeve-like member which is slidable on the lifting arm and which has means to which a suspension device is attached or is attachable, releasable locking means for releasably locking the sleeve-like member in a position in which it is fully engaged with the lifting arm, and complementary means on the sleeve-like member and lifting arm for forcing the sleeve-like member to be tilted relative to the lifting arm in order that it can be removed from the lifting arm.

2. A fastening arrangement as claimed in claim 1, wherein the lifting arm is of circular outer cross-section and the sleeve-like member has a bore of circular crosssection and means are provided for preventing the sleeve-like member swivelling relative to the lifting arm about the axis of the sleeve-like member.

3. A fastening arrangement as claimed in claim 1 or claim 2, wherein the complementary means comprises two opposed projections on the lifting arm and a pair of grooves in the inner wall of the sleeve for co-operating respectively with the two projections, the grooves being inclined to the longitudinal axis of the sleeve-like member.

4. A fastening arrangement as claimed in claim 3, wherein the inner ends of the grooves communicate with slots which extend parallel to the longitudinal axis of the sleeve-like member and in which the projections engage as the sleeve-like member reaches a position in which it is fully engaged with the lifting arm.

5. A fastening arrangement as claimed in claim 1 or claim 2, wherein the complementary means comprises two opposed projections on the sleeve-like member and a pair of grooves in the outer wall of the lifting arm for co-operating respectively with the two projections, the grooves being inclined to the longitudinal axis of the lifting arm.

6. A fastening arrangement as claimed in claim 5, wherein the inner ends of the grooves communicate with slots which extend parallel to the longitudinal axis of the lifting arm and in which the projections engage as the sleeve-like member reaches a position in which it is fully engaged with the lifting arm.

7. A fastening arrangement as claimed in any one of the preceding claims, wherein the sleeve-like member has a first sleeve at its outer end for receiving the free end of the lifting arm and a second oblique sleeve at its inner end, the first sleeve being joined to that portion of the second sleeve nearest to the first sleeve and there being an opening between the first sleeve and that portion of the second sleeve furthest from the first sleeve which opening receives the free end of the lifting arm after the latter has been removed from the first sleeve and as the sleeve-like member is tilted relative to the lifting arm.

8. A fastening arrangement as claimed in claim 7, wherein the portion of the second sleeve nearest to the first sleeve is uppermost in use and the top of the second sleeve is axially offset from the bottom of the second sleeve.

9. A fastening arrangement as claimed in any one of the preceding claims, wherein the releasable locking means comprises a spring-loaded plunger which is provided on the lifting arm and which is engageable in a hole in the sleeve-like member when the sleeve-like member is in a position in which it is fully engaged with the lifting arm.

10. A fastening arrangement as claimed in claim 9, wherein the releasable locking means also comprise a release button for moving the plunger to a release position against its spring loading.

11. A fastening arrangement as claimed in any one of the preceding claims, wherein the sleeve-like member includes a pin projecting into its bore for locating in a hole in the lifting arm when the sleeve-like member is fully engaged with the lifting arm.

12. A fastening arrangement as claimed in any one of the preceding claims, wherein the sleeve-like member has support means at its outer end for supporting a suspension device.

13. A fastening arrangement as claimed in claim 12, wherein the support means supports a suspension device for swivellable movement about a vertical or substantially vertical axis.

14. A fastening arrangement substantially as hereinbefore described with reference to the accompanying drawings.

15. A hoist having a lifting arm and a fastening arrangement according to any one of the preceding claims.

16. A hoist as claimed in claim 15, further including an upstanding column supporting the lifting arm.

17. A hoist as claimed in claim 16, wherein the upstanding column is telescopic to raise and lower the lifting arm.

18. A hoist as claimed in claim 16, wherein the upstanding column includes means for raising the lifting arm relative to the column.

19. A hoist as claimed in any one of claims 16 - 18, wherein the column is supported on a mobile chassis.