AU675956B2 - Improvements in mobile hoists - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 M D T. r T P RTBC'T nT C NN q P E C I F I C A T 1 0 FOR A STANDARD PATENT

ORIGINAL

S. Name of Applicant: Actual Inventor: Address for Service: Invention Title: PETER CHARLES CHRISTOFFER VAN ZIJLL DE JONG Peter Charles Christoffer Van Zijll de Jong SHELSTON WATERS Clarence Street SYDNEY NSW 2000 "IMPROVEMENTS IN MOBILE HOISTS" The following statement is a full description ef this invention, including the best method of performing it known to me:- I 1 -2, The invention relates to mobile hoists, and has particular but not exclusive application to self-propelled mobile hoists of the kind used in orchards and similar plantations to transport an operator from place to place for example during tree-pruning or fruit-picking operations and to raise and lower the operator to and from a desired working height and position at each place.

Because of the limited room available for manoeuvring such .hoists in orchards. in particular, damage to trees may occur 10 during movement of such a hoist within and between different places in the orchard.

The invention seeks to provide improvements in the design and construction of such hoists whereby the risk of such damage is reduced in comparison with that presented by ooo existing hoists used for the purposes mentioned.

Such existing hoists have a mobile chassis supported on a pair of drive wheels mounted one on each side of the chassis at a leading end thereof, and on a caster wheel mounted centrally of the width of the chassis at a trailing end thereof. A motor mounted on the chassis betweem its leading and trailing ends is drivably connected to the drive wheels in a manner that enables both forward and reverse propulsion of the hoist, and independent rotation of the drive wheels in opposite directions. A boom is pivotally attached at one end portion of the boom to a mounting I V- -3provided at the trailing end part of the chassis, adjacent to the caster wheel, so that the boom is pivotable between a lowered position in which it extends forwardly and more or less horizontally from its pivot point to project beyond the leading end of the chassis, and a raised position in which it extends upwardly and forwardly from its pivot point to a desired operating height. Raising and lowering of the boom is effected by means of a hydraulic cylinder acting between "the pivoted end portion of the boom and the chassis. An 10 operator's cage or platform is adjustably mounted at the free end of the boom and is provided with controls enabling an operator standing in the cage to operate the motor and associated drive means and the hydraulic ram so as to raise and lower the boom and move the hoist from one place to another in an orchard or the like, and to different positions within each place.

0 *.a When an existing hoist of the kind just described is in use in an orchard, the design of the hoist requires that its drive wheels be presented to the tree on which work is being performed. At the same time the greater part of the loading imposed by the weight of the cage and operator at the upper end of the raised boom, and of the motor, is transmitted to the caster wheel at the trailing end of the chassis. In consequence, there is a loss of manoeuvrability of the hoist in the vicinity of the tree concerned and because of the arc of swing of the trailing end of the hoist during repositioning of the hoist a likelihood of damage to neighbouring trees in the restricted I Ir bl L~ -4space available in most orchards. Successful operation of the hoist in those circumstances calls for quite a high level of skill on the part of the operator.

According to the invention there is provided a mobile hoist consisting of: a mobile motorised chassis that extends between a trailing end and a leading end of the chassis and is supported at its trailing end on a pair of drive wheels mounted on opposite sides of the chassis, and at its leading end on a caster that is mounted centrally of the width of the chassis and is swivelled to a fixed tow-bar-like armnn that constitutes a leading end member of the chassis and is of reduced width in relation to the rest of the chassis; hydraulic drive means mounted on the chassis between the drive wheels and drivably connected to the drive wheels and including a motor operable to drive a hydraulic pump and hydraulic hub motors provided in the drive wheels; hydraulic control means whereby the drive wheels can be driven so as to provide forward and reverse propulsion of the hoist and independent rotation of tbe drive wheels o. 00 15 in opposite directions; a boom pivotally attached at one end part thereof to the chassis between the drive wheels and centrally of the width of the chassis and pivotable between a lowered position in which it extends towards and beyond the leading end of the chassis and a raised position in which it extends upwardly from the chassis to a position above the caster; an operator's cage adjustably mounted at the free end part of the boom; means for maintaining the cage in an upright position during raising and lowering of the boom; 17097-.00.Doc/mja 4a means operable by the said hydraulic drive means so as to raise and lower the boom between its said positions; and hydraulic control means carried by the cage and operable by an operator within the cage so as to control the operation of the said hydraulic drive means and the raising and lower:.ig of the boom.

The invention enables the leading end portion of the chassis to be narrowed to become little more than a strut or tow bar extending forwardly from the motor-bearing portion of the chassis and having the caster wheel mounted beneath its leading end portion. The leading end portion so constituted may be arranged to provide a support for S 10 the intermediate portion of the boom when the boom is in its lowered position. In that position, also, the operator's cage will be pivoted on its mounting at the free end of the boom to an upright pc sition, and if the hoist is not being towed it can be driven under its own power for example along an orchard lane by an operator standing in the cage.

00 When a mobile hoist modified as described above is in use for pruning or fruit- 15 picking purposes within an orchard, the repositioning of the hoist in relation to a tree being worked on is made easier by the reduced width and the Ios7oo.Doc/nija castering action of the leading end of the chassis; also by the fact that the greater part of the loading at the raised end of the boom is transmitted to the drive wheels at the trailing end of the chassis, rather than to the caster wheel as in existing hoists of the kind described above.

A mobile hoist constructed in accordance with the invention will now be described by way of example of how the invention can be carried into effect and with reference to the accompanying drawings. in which:- *0 0 *0 0* Figure 1 Figure 2 Figure 3 is a perspective view of the hoist, showing its components in an operating position; is a plan view of the hoist, showing its components in a lowered and travelling position, but also indicating in outline a raised and operational position of one component; is a front elevation of the hoist in its lowered and travelling position shown in Figure 2, but also indicating in outline a raised and operational position of a part of the hoist; and is a side elevation of the hoist as shown in Figure 3.

Figure 4 As shown in the drawings, the hoist has a mobile motorised chassis (indicated generally at 1) supported at one end on a pair of drive wheels 2 mounted one on each side of the chassis, and supported at its other end on a caster 3 IL I -6disposed centrally of the width of the chassis, and swivelled to a fixed tow-bar-like arm 4 constituting a leading end member of the chassis 1. The caster 3 comprises a pair of wheels 5 rotatably mounted on a swivel block 6 which is turnably engaged with the leading end portion of the chassis member 4.

At its opposite (or trailing) end part, between the drive wheels 2. the chassis 1 carries a motor 7 and fuel and hydraulic-oil tanks 8. The drive wheels 2 are independently driven in a known manner by a pair of hydraulic motors incorporated in the driving wheel hubs and in turn driven from a hydraulic pump operated by the motor 7 to pump hydraulic oil through hydraulic hose connections to the hydraulic motors in the drive wheels 2. Conventional hydraulic flow controls enable the wheels 2 to be driven to provide both forward and reverse propulsion of the hoist, and independent rotation of the wheels 2 in opposite directions so as to turn the hoist in either direction.

A boom 9 is pivotally attached at one end portion of the boom to a mounting 10 provided on the chassis 1 as a fixed component thereof, located midway between the drive wheels 2 at the trailing end part of the chassis 1. The boom 9 is pivotable between a lowered position (shown in full lines in Figures 3 and 4 of the drawings) in which the boom extends forwardly and at a downward angle from its pivot point to project beyond the leading end of the chassis member 4, and

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-7a raised position (shown in full lines in Figures 1 and 2 of the drawings and in partial broken outline in Figures 3 and 4) in which it extends upwardly and forwardly from its pivot point to a desired operating height. Raising and lowering of the boom 9 is effected by means of a hydraulic cylinder 11 acting between the chassis 1 and the pivoted end portion of the boom 9.

An operator's cage and platform 12 is adjustably mounted at the free end of the boom 9, and is provided with hydraulic controls 13 enabling an operator standing in the cage 12 to operate the motor 7 and associated hydraulic drive means and the hydraulic cylinder 11 so as to raise and lower the boom *9 9 and move the hoist from one place to another in an orchard or the like, and to different positions within each place.

15 A link rod 14 extends between the cage 12 and the chassis :99 mounting 10 and the cage 12, parallel with the boom 9, and is pivotally attached at its end portions to the upper end part of the mounting 10 and to a yoke member 15 secured to the lower rear part of the cage 12. The corresponding end of the boom 9 is likewise pivotally attached to the yoke member 15, so that the boom 9 and link rod 14 together provide a parallelogram linkage between the chassis component 10 and the cage 12 (as is shown particularly in Figure 4 of the drawings). This ensures that the cage 12 remains in a substantially upright position during movement between its raised and lowered positions shown respectively in Figures 1 and 4 of the drawings.

~111~ 1 -r I= I i" I 8 As is shown particularly in Figure 2 and also in Figures 1 and 4 of the drawings, the cage 12, when in its fully raised and operational position shown in full lines in Figure 1 and in outline in Figures 2 and 4, is located substantially directly above the caster 3. This facilitates an operator's access to branches being pruned or other work being performed from the operator's position in the cage.

At the same time the parallelogram linkage of the cage 12 to the chassis member 10 by the boom 9 and link rod 14 results 10 in a major part of the load imposed by the weight of the cage 12 and the operator within the cage being transmitted to the motor-bearing portion of the chassis 1 and to the drive wheels 2 of the hoist. This enhances the driving grip of the drive wheels 2 and at the same time reduces loading on the caster 3, thereby facilitating movement and repositioning of the caster 3 and cage 12 in relation to a

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tree being pruned in an orchard, or other work being carried out from the cage by the operator.

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Likewise, the repositioning of the hoist for travel along an orchard lane is made easier by the fact that the smallest turning circle of the hoist is at its trailing end, between the drive wheels, and this will normally be already in the lane beside the tree being worked on.

When the cage 12 is in its lowered position shown in Figure 4. it can be readily driven along an orchard lane or the like by an operator standing in the cage and operating the controls 13 so as to control the drive from the motor 7 to II I II I I 9the hydraulic hub motors of the driving wheels see.

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Claims (4)

1. A mobile hoist consisting of: a mobile motorised chassis that extends between a trailing end and a leading end of the chassis and is supported at its trailing end on a pair of drive wheels mounted on opposite sides of the chassis, and at its leading end on a caster that is mounted centrally of the width of the chassis and is swivelled to a fixed tow-bar-like arm that constitutes a leading end member of the chassis and is of reduced width in relation to the rest of the chassis; hydraulic drive means mounted on the chassis between the drive wheels and 0 drivably connected to the drive wheels and including a motor operable to drive a S. hydraulic pump and hydraulic hub motors provided in the drive wheels; hydraulic control means whereby the drive wheels can be driven so as to provide forward and reverse propulsion of the hoist and independent rotation of the drive wheels in opposite directions; a 15 a boom pivotally attached at one end part thereof to the chassis between the drive wheels and centrally of the width of the chassis and pivotable between a lowered *pp position in which it extends towards and beyond the leading end of the chassis and a raised position in which it extends upwardly from the chassis to a position above the caster; an operator's cage adjustably mounted at the free end part of the boom; means for maintaining the cage in an upright position during raising and lowering of the boom;

17097-o00 oc/nlja ~il II I I I 11 means operable by the said hydraulic drive means so as to raise and lower the boom between its said positions; and hydraulic control means carried by the cage and operable by an operator within the cage so as to control the operation of the said hydraulic drive means and the raising and lowering of the boom.

2. A mobile hoist according to claim 1, and in which the caster comprises a pair of wheels rotatably mounted on a swivel block which is turnably engaged with the leading end of the said leading end member of the chassis.

3. A mobile hoist according to claim 1, and in which the means for maintaining the operator's cage in an upright position during raising and lowering of the boom consist of a link rod extending between and pivoted to the cage and the chassis so that in conjunction with the boom it forms a parallelogram linkage between the chassis and the cage. e

4. A mobile hoist according to claim 1, and wherein the means for raising and lowering the boom include a hydraulic cylinder attached to and acting between the chassis and the pivoted end part of the boom, and operable by the hydraulic control means. A mobile hoist having its parts constructed, arranged, and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings. DATED this 16th Day of December, 1996 PETER CHARLES CHRISTOFFER VAN ZIJLL DE JONG Attorney: JOHN B. REDFERN Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS 17097.(laDOC1111j a _I~C~II~~ 12 ABSTRACT A hoist has a mobile motorised chassis (1) supported at one end on a pair of drive wheels (2) mounted on each side of the chassis and supported at its other end on a castor disposed centrally at the width of the chassis, and swivelled to a fixed tow-bar-like arm constituting a leading end member of the chassis The castor comprises a pair of wheels rotatably mounted on a swivel block which is turnably engaged with the leading end portion of the chassis member L I LM