AU664575B2 - A lifting device - Google Patents

Description

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AUSTRALIA

Patents Act 1990 *u CX -L 1 FIE= EyECZI 3F I C:AT *4 I U, C Invention Title: Applicant: A LIFTING DEVICE ANTHONY PHILIP DUNKS The following statement is a full description of this invention, including the best method of performing it known to us: WP51/JMSPEC/DUNKS. CAP/4 December 1992/D3 2 TITLE! A Lifting Device FIELD OF THE INVENTION: The present invention relates to a lifting device and more particularly to a lifting device which enables an object to be lifted from a surface and then wheeled away to another location.

BACKGROUND OF THE INVENTION: ItLhough numerous devices such as cranes and fork-lifts have been developed to move heavy and cumbersome items it is not always feasible to make use of those I r devices to lift some items. For example, when shifting props in a theatre production, quick and quiet movement is required and therefore it would not be possible to use a fork-lift.

Furthermore, in some situations where there is limited working space it is not possible to manoeuvre a fork-lift or a crane into position next to the object.

Some objects that need to be moved periodically are mounted on castors. However, it has been found that when castors are used to support heavy objects the surface upon which the object is resting may be dented by the castors. Another problem is that i the castors themselves may become flattened because of the weight Sthey are supporting and thus become difficult to roll.

The present invention seeks to provide a simple and inexpensive lifting device which can be quickly attached to an object and which enables the object to be easily lifted so that it can be WP51/JMSPEC/DUNKS CAP/4 December 1992/D3

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BRIEF SUMMARY OF THE INVENTION: This invention provides a lifting device for lifting an object off a surface, which comprises a first component arranged to be secured to the object, a second component slidably engaged with the first component, and lifting means co-operating with said first and second components such that, when the lifting means is moved from a first position to a second position, a lift force is produced on the object, raising it from engagement with the surface.

In another aspect this invention provides a lifting device for lifting an object off a surface, which comprises a first component arranged to be serured to the object, a second component slidably engaged by t.onnection means with the first component, and lifting means with the first component, and lifting means co-operating with said first and second components

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such that, when the lifting means is moved from a first position to a second sition, a lift force is produced on the object, raising it engagement with the surface.

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This invention also provides a method of moving objects wherein Sa plurality of lifting devices is attached to an object for S.movement with respect to a surface by rolling on castors or other means.

WP51/JMSPEC/DUNKSCAP/4 De.ember 1992/D3 4 DETAILED DESCRIPTION OF THE INVENTION: Preferably the connection means comprises a shaft means slidably engaged within sleeve means; the first component being movable with respect to the second component in a direction substantially parallel to the longi-udinal action of the shaft means upon operation of the lifting means.

Preferably the shaft means rotates within the sleeve means when the lifting means is rotated from the first position to the second position.

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The invention preferably comprises a frame portion and a sleeve member, the sleeve member forming part of the shaft means.

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Preferably the frame portion and the sleeve member are connected S* by spacing means whereby the frame portion of the first component is separated from the second component.

a S Preferably the frame portion comprises attachment means to attach the first component to the object which is to be lifted.

Preferably the second component comprises a shaft having a first end arranged to slidably engage within the sleeve member and a )second end having a flange extending radially outwards, the top surface of the flange being arranged to form a cam surface.

WP51/JMSPEC/DUNKS.CAP/4 December 1992/D3 I EI r 1 Preferably a lifting means in the form of a cam is pivotally connected to the sleeve member, which may be reinforced by a support means, so that the cam surface of the cam engages with the cam surface of the flange.

Preferably a lifting arm is attached to the cam, Preferably the profile of the cam is such that, when the cam is pivoted about the pivoted connection from a first position to a second position, the first component is lifted upwardly with respect to the second component in a direction substantially 0 00 parallel to the longitudinal axis of the shaft.

0 00 Preferably the shaft is arranged to rotate as the cam is pivoted about the pivotal connection, whereby rotation of the shaft and 0 0 flange facilitates movement of the cam over the cam surface and keeps wear between the cam and the cam surface.

Preferably the first and second components are joined by biasing means which maintains the first component adjacent the second 0040 component except when a lifting force is applied to the first component.

Preferably the biasing means comprises spring means arranged to be in a closed condition when the first and second components are adjacent and in an extended condition when a lifting force is applied to the first component.

WPS1/JMSPEC/DUNKS.CAP/4 December 1992/03

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6 Preferably the frame portion is adapted to co-operatively engage a plate attached to the object to be lifted.

Preferably locking means is provided to maintain engagement between the plate and frame portions when the object is lifted off the surface.

I Preferably the locking means is arranged to prevent relative movement between the frame portion a~id the plate.

Preferably the second component is pivotally secured to a castor such that the longitudinal axis about which the castor is pivoted is co-axial with that region wherein the first and second components join.

Preferably rotational movement of the castor is independent of any rotational movement of the first and/or second components.

BRIEF DESCRIPTION OF THE DRAWINGS: An embodiment of the It invention will now be described by way of example only with reference to the accompanying drawings in which:- Figure 1 is a side part cross-sectional view of an embodiment of I{ the lifting device in the lifted position; s Figure 2 is a detailed cross-sectional view of the connection between first and second components of the device; Figure 3 is a side view of the cam in the non-lift position; Figure 4 is a front view of a connector plate; and WP51/JMSPEC/DUNKS.CAP/4 December 1992/D3 -iwoo Figure 5 is a side view of the connector plate shown in Figure 4.

DETAILED DESCRIPTION OF THE INVENTION: The lifting device illustrated in Figure 1 comprises a first component 12 which is arranged to be secured to an object 14 which is to be lifted, a second component 16 and a castor 18. Figure 1 illustrates the device 10 with the object 14 in a raised position above the ground surface.

The first component 12 comprises a frame portion 20 and a sleeve ~22. The frame portion 20 comprises a cross member 21 and a pair 0: of depending arms 23 which form an inverted V-shape. Cross 0. 0 member 21 spaces the arms 23 horizontally from said sleeve 22 and second component 16. The second component 16 comprises a hollow 'o 0 shaft 24 having a first end 26 arranged to slidingly engage and 0, 00 freely rotate within the sleeve 22. Secured to a second end 28 S of the hollow shaft 24 and extending radially of the outer surface of the shaft 24 is a flange 30. The underside 32 of the flange 30 is rigidly attached to a castor bearing 34. Castor 18, which is a conventional castor, is attached to the castor bearing 34 by a pin 36 such that the castor 18 is free to swivel about the longitudinal axis of the pin 36.

The first component 12 and second component 16 are secured together by a spring 40. Spring 40 is housed within the hollow shaft 24. A first end 44 of the spring is hooked about a pin 46 WP51/JMSPEC/DUNKS.CAP/4 December 1992/03 r I r 8 which extends horizontally across the diameter of the shaft 24.

The ends 46a, 46b of the pin 46 are held within respective apertures 47a, 47b in the shaft 24. The second end 48 of the spring 40 is held in an aperture 49 in a retaining plug Retaining plug 50 is mounted in a bearing 52 in the upper opening of the sleeve 22. The provision of the bearing 52 and the connection thereof to the spring 40 enables the spring 40 to rotate about its longitudinal axis when the hollow shaft 24 is caused to rotate within the sleeve 22.

A lifting means 60 in the form of a cam 62 is pivotably connected by a screw 64 to a suppport means 22a attached to the sleeve 22.

As shown in Figure 3, a lifting arm 66 is attached to the cam 62.

The cam 62 is pivotally connected to the sleeve 22 so that the cam surface 68 of the cam 62 is arranged to contact the upper side 31 of the flange The raise or lower the lifting device 10, the cam 62 must be moved from a first position (as shown in Figure 3) to a second position (as shown in FV ure In the first position, the flat portion 68a of the cam surface 68 is positioned substantially vertically above the screw 64. In this position of the cam 62 the distance Y between the upper surface 31 of the flange 30 and the centre of the screw 64 is at a minimum.

To raise the lifting device 10, cam 62 is rotated about screw 64 so that the flat portion 68a of the cam surface 68 contacts the WPSI/JMSPEC/DUNKS.,CAP/4 December 1992/D3

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I I 9 Supper surface 31 of the flange 30. As the cam 62 is rotated the ii contact between the cam surface 68 and the upper surface 31 of bearing 34 to rotate about the longitudinal axis of the hollow shaft 24. Spring 40 is also caused to rotate. Rotational movement of the second component 16 and the castor bearing 34 during rotation of the cam 62 facilitates easy movement of the cam surface 68 over the upper surface 31 and the flange 30 and thereby helps to reduce wear of the upper surface 31 and the cam surface 68. If the flange 30 remained stationary a greater force would be required to rotate the cam 62 because of the frictional resistance between the upper surface 31 of the flange and the cam surface 68 of the cam 26.

As can be seen in Figure 1, which illustrates the device 10 in I *a raised position, the distance Y between the upper surface 31 and the centre of the screw 64 is at a maximum. As the cam 62 o is secured to the sleeve 22 of the first component 12, the first o component 12 will be raised upwardly in a direction substantially parallel to the longitudinal axis of the sleeve 22 when the cam 62 is moved from the position as shown in Figure 3 to the position as shown in Figure 1.

Figure 1 also illustrates one method of attaching an object 14 to the frame portion 20 of the first component 12. In this arrangement a connector plate in the form of a length of L-shaped section 100 1s secured by counter sunk fasteners 101 to the WP51/JMSPEC/DUNKS.CAP/4 Docombor 1992/D3 object 14. The upright plate 102 of the L-shaped section 100 includes a pair of slots 104 into each of which a pin 106 may be received. Each slot 104 is shaped so that a pin 106 once received in the slot 104 can rest in either one or two stable positions. These two positions are spaced vertically. The head of a pin 106 can only enter a slot 104 in the lower most position. Pins 106 extend from a plate 108 which is welded to the depending arms 23 of the frame portion To lock the device 10 to an object 14 pins 106 are inserted into the slots 104 in the L-shaped section 100. When the pins 106 are within the slots 104 upward lift is applied to the device 10 so that the pins 106 are caused to move to their second stable position within the slots 104.

00 The L-shaped section 100 does not move vertically when this lift 0 0 force is applied because of the weight of the object 14. A .0 locking pin 110 fixed within an aperture 112 extends through one S of the arms 23 of the frame portion 20 and through plate 108.

The distal end 114 of the locking pin 110 extends out of aperture 112 so that it engages within a groove 116 or other aperture cut in the end portion 102a of the upright plate 102 of the L-shaped section 100. Locking pin 110 is secured within the aperture 112 by a spring arrangement 120. Spring arrangement 120 enables the locking pin 110 to be partially retracted from the aperture 112 so that the distal end 114 of the locking pin 110 can be disengagedL from the groove 116. When the distal end 114 of the WP51/JMSPEC/DUNKS.CAP/4 December 1992/D3 L MItMO=ft

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i 1$ ii 1 11 locking pin 110 is engaged within the groove 116 pins 106 cannot be released from the slots 104 in the L-shaped section 100.

When the locking pin 110 is disengaged pins 106 can be lowered within each of the slots 104 to the first stable position so that the head of each pin 106 can be removed from the slots 104.

Locking pin 110 prevents relative longitudinal movement between the plate 108 and the L-shaped section 100.

9, To lift an object 14 a number of devices 10 would be secured about the periphery of the object 14. Once the lifting devices were secured to the object 14 the lifting arm 66 and cam 62 on each device 10 would be rotated about screw 64 so that the distance Y reaches a maximum. With each of the lifting devices in a raised position (as shown in Figure 1) the object 14 can easily be wheeled to another position.

Although the pins 106 have been described as extending from the plate 108 in an alternative arrangement the pins 106 may be S mounted on the connection plate and the grooves may be in the S plate 108.

9, The embodiment has been described by way of example only and modifications are possible within the scope of the invention.

WP51/JMSPC/DUNKSCAP/4 December 1992/D3 r i i -1 r

Claims (19)

1. A lifting device for lifting an object off a surface, which comprises in combination a first component arranged to be secured to the object, a second component slidably engaged by connection means with the first component, and lifting means co-opertaing with said first and second components such that, when lifting means is moved from a first position to a second position, a lift force is produced on the object, raising it from engagement with the surface, wherein the connection means comprises a shaft means slidably engaged within sleeve means; the first component being movable with respect to the second component in a direction substantially parallel to the longitudinal action of the shaft means upon operation of the lifting means, and wherein the shaft means rotates within the sleeve means when the lifting means is rotated from the first position to the second position.

2. A lifting device as claimed in claim 1, wherein the first component comprises a frame portion and a sleeve member, the sleeve member forming part of the shaft means.

3. A lifting device as claimed in claim 2, wherein the frame portion and the sleeve member are connected by spacing means whereby the frame portion of the first component is separated from the second component,. i 4. A lifting device as claimed in claim 2 or claim 3, wherein the frame 1 portion comprises attachment means to attach the first component to the r object which is to be lifted.

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5. A lifting device as claimed in any one of claims 2 to 4, wherein the second component comprises a shaft having a first end arranged to slidably rl, engage within the sleeve member and a second end having a flange extending radially outwards, the top surface of the flange being arranged to form a cam surface. -I RA H /VT 0 F"1 I i i -13-

6. A lifting device as claimed in claim 5, wherein a lifting means in the form of a cam is pivotally connected to the sleeve member so that the cam surface of the cam engages with the cam surface of the .ange.

7. A lifting device as claimed in claim 6, wherein a lifting arm is attached to the cam.

8. A lifting device as claimed in claim 6 or claim 7, wherein the profile of the cam is such that, when the cam is pivoted about the pivoted connection from the first position to a second position, the first component is lifted upwardly with respect to the second component in a direction substantially parallel to the longitudinal axis of the shaft.

9. A lifting device as claimed in claim 8, wherein the shaft is arranged to rotate as the camn, is pivoted about the pivotal connection, whereby rotation of the shaft and flange facilitates movement of the cam over the cam surface and reduces wear between the cam and the camn surface. E A lifting device as claimed in any one of claims 1 to 9, wherein the first and second components are joined by biasing means which maintains the A ,f irst component adjacent the second component except when a lifting force is applied to the first component.

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11, A lifting device as claimed in claim 10, wherein the biasing means comprises spring means arranged to be in a closed condition when the V first and second components are adjacent ard in an extended condition J when a lifting force is applied to the first component.

12. A lifting device as claimed in any one of claims 1 to 11, wherein the frame portion is adapted to co-operatively engage a plate attached to the object to be lifted. 'i

13. A lifting device as claimed in claim 12, wherein locking means is provided to maintain engagement between the plate and frame portions when the object is lifted off the surface. -14-

14. A lifting device as claimed in claim 13, wherein the locking means is arranged to prevent relative movement between the frame portion and the plate.

A lifting device as claimed in any one of claims 1 to 14, wherein the second component is pivotally secured to a castor such that the longitudinal axis about which the castor is pivoted is co-axial with that region wherein the first and second components join.

16. A lifting device as claimed in claim 15, wherein rotational movement of the castor is independent of any rotational movement of the first and/or second components.

17. A lifting device as claimed in claim 1, substantially as described with reference to the accompanying drawings.

18. A method of moving objects wherein a plurality of lifting devices as claimed in claim 1 is attached to an object for movement with respect to a surface by rolling on castors or other means.

19. A method of moving objects aits claimed in claim 18, substantially as described with reference to the accompanying drawings. Pi;' I DATED this 2nd day of February 1995 ANTHONY PHILIP DUNKS by His Patent Attorney I- ABSTRACT A lifting device for lifting an object off a surface, which comprises a first component (12) arranged to be secured to the object, a second component (16) slidably engaged (22, 24) with the first component, and lifting means (60) co-operating with said first and second components (30) such that, when the lifting means is moved from a first position to a second position, a lift force is produced on the object, raising it from engagement with the surface. a a no a4 a a a a *4 a 0 0 i 1k ri* WP51/JHSPEC/OUNKS.CAP/4 December 1992/03