NZ264708A - Vehicle three part side mounted platform being maintained horizontal during lowering and raising in a near vertical motion - Google Patents

Description

New Zealand No. 264708 International No. PCT/ TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 17.10.1994 Complete Specification Filed: 11.10.1995 Classification: (6) B60P1/44 Publication date: 26 August 1998 Journal No.: 1431 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Self levelling vehicle mounted goods loading and unloading platform Name, address and nationality of applicant(s) as in international application form: LYAL HAROLD BARRETT, a New Zealand citizen of 70 Cressida Avenue, Stratford, New Zealand The platform incorporates electro hydraulic devices for the raising, lowering and docking of the platform.

Also maintaining the platform in a true horizontal plane during the loading and unloading operation.

The platform is controlled in' its elevation and descent by a system of levers that produce a near vertical loci motion to the platform.

The platform is self docking and contained within the side extremities of the vehicle when docked.

The platform also incorporates a drop down toe that raises a barrier to prevent wheeled loads from running off the platform, until the platform is resting on the ground.

Various safety devices are incorporated in the design to prevent mis-operation or personal injury. r Z. FAYtli'iT OFFiCS 17 OCT 1994 RECEIVED Position of Docked- Platform. u -c u V. o r^. <&> 2 O ^ Raised position <of loaded Platform Tilt to accommodate ^Rooel Camber O X Hi r\ K- •;-o <r < tt- O Tii > a r.c Platform Tilt to accommodate. |q Rodd Comber End Eleva Hon 264?08 NEW ZEALAND PATENTS ACT 1953.

COMPLETE SPECIFICATION With priority to provisional specification No. 264708 Dated 17th Oct. 1994 SELF LEVELLING VEHICLE MOUNTED GOODS LOADING AND UNLOADING PLATFORM.

I, LYAL HAROLD BARRETT of 70 CRESSIDA AVE, STRATFORD, NEW ZEALAND, being a New Zealand Citizen;- HEREBY declare the invention, for which i pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: Para 1. This invention relates to a side loading platform suitable for goods delivery vehicles which does not compromise the vehicles chassis and is self-levelling regardless of road camber. 264708 Para 2. The delivery of stackable or palleted goods from warehouses to retail outlets is not always able to be carried out by mechanical handling methods such as fork lift trucks, because of the limited goods delivery access and in many cases only through the public entrance of retail establishments.

Para 3. The use of hand trucks or wheeled platforms to effect delivery has meant that many goods delivery vehicles have been fitted with a means of lifting or lowering loaded pallets or wheeled platforms between the ground and deck level. These often take the form of a tailgate loader or similar powered platform attached or built into the transport vehicle.

Para 4. While this solution obviates the need to restack the goods, the fact that the platform is invariably not truly horizontal, means a tall stack of goods is rendered unstable and likely to topple causing damage. This condition is accentuated if the platform is side mounted on the goods delivery vehicle, due to the camber of the road adjacent to the curb when the vehicle is parallel parked. Also many of the present options necessitate considerable modifications to the transport vehicle, possibly compromising the vehicles integrity.

Para 5. The object of this invention is to provide a work platform which maintains a horizontal orientation within its operating height range.

One preferred form of this invention is briefly described hereunder: - The platform and its associated linkage is built on a demountable frame which is "U" bolted to the transport vehicles chassis members. The associated linkage controls both the horizontal orientation and vertical loci motion of the platform, transmitting the force of the hydraulic rams as demanded by a control circuit. 264708 The platform consists of three sections, heel, middle, and toe. The heel section is attached to the linkage and the middle section is pivotally connected to the heel section, which on its extreme end carries the pivotal toe section. The outer toe section forms a barrier to wheeled loads when the platform is off the ground and becomes a ramp when the platform is resting on the ground, also isolating the control circuit preventing further movement of the platform until upward movement is required. The middle section of the platform is prevented from involuntarily folding up when the toe is sitting on the ground, by a dual purpose platform lock. For transport, the middle and toe sections pivot to a vertical docked position by a projected pin reacting with a safety docking/transport catch, when the platform locking pin is retracted. The toe and middle section dock within the extremities of the transport vehicle.

A gravitational inclinometer is attached to the heel section, sensing the horizontal orientation and outputting a signal to the control circuit of the levelling ram. An external positioner controls the levelling ram to orient the platform into the docking mode.

A safety device is fitted to the deck-well trim, to detect any obstruction that is caught in the "nip gap" between the platform and the deck-well opening. This takes the form of a pressure sensitive device that isolates all the control circuits with the exception of the down circuit. Other safety devices, such as toe and hand rails, can be fitted to the sides of the heel section without interfering with the platforms operation.

This invention is adaptable to varying physical restraints. A larger and/or longer platform may require two sets of rams and linkages, set at the extreme ends or even outboard of the platform, to retain the desired stability. 264708 The physical form of the linkages can be modified to suit the space available and/or various mounting positions and types of transport vehicles.

One preferred variation of this invention is a single set of rams and linkages hereby described in more detail with due reference to the accompanying drawings.

Figure 1. is the side view of the invention in the various modes of loading, levelling and docking, showing the layout of the invention side mounted on the support vehicle and looking from the rear.

Figure 2. is an end view of the invention looking from the curb side of the support vehicle and shows the platform stowed in the docking position ready for transport.

Figures 3.4. 5. & 6. show the operation and position status of the linkages and hydraulic rams at various heights being Deck level, Quarter descent, Three-quarter descent and Full descent to the ground, respectively.

Figure 7. depicts the dual purpose platform lock viewed from above with the platform locking pin engaged.

Figure 8. depicts the dual purpose platform lock, viewed from below with the locking pin retracted and the docking pin engaging the forked catch arm of the safety docking transport catch as in Figure 13.

Figure 9. depicts the gravitational inclinometer. Figure 9a being the plan view. Figure 9b being the elevation.

Figure 10. depicts the external positioner for monitoring the levelling ram when the platform is in docking mode.

Figure 11. depicts the pressure sensitive safety device fitted to the deck-well trim.

Figure 12. depicts a docking transport catch and safety lock in the locked position when the platform is docked. 264708 Figure 13. depicts the docking transport catch and safety lock in the released position when the platform is in working mode with the docking pin retracted.

Figure 14. depicts the control circuit logic of the invention.

Figure 15. depicts in pictorial terms the mounting and operation of the described form of this invention. Figure 15a shows the platform lowered to the curb and compensating for the camber of the road.

Figure 15b shows the platform docked within the extremities of the support vehicle and ready for transport. Figure 15c shows the platform raised to deck level and the ground sensing toe pivoted to expose the barrier to wheeled loads.

Detailed Specifications Referring to the accompanying drawings:- The support vehicle illustrated is of conventional construction and its outline is depicted as #1. The load carrying platform shown here consists of three sections; the heel #2, middle #3 and toe sections #4. The main frame which is demountable from the support vehicle chassis is shown as #5. This frame rests on top of the chassis runners #6 and is fastened with conventional "U" bolts. The main frame carries various fixed pivots to which the linkages and rams are connected. The lifting force is exerted by the lift ram #7 the rod eye being pivotally attached to the main frame at #55. The ram #7 is centrally mounted between the frame members #5 and as the linkage is equally disposed either side of the frame/platform centre line refer Figure 2, then only one side if the linkage will be described.

The ram #7 is of the single acting retraction type, the flexible piston seal drain hose being plumbed back to the hydraulic reservoir as the platform and linkage have sufficient mass for gravity to act as the downward force, thus eliminating any tendency for the platform to "jack up" the support vehicle when the load carrying platform #2,#3,& #4 rests on the ground or curb. The ram #7 carries a trunion mounting on the cylinder and is pivotally attached to the control link #8 causing it to rotate about a fixed axis #9 on the main frame. On the outer end of the control link #8 a pivoted connection is made to the main lifting link #10. The lifting link #10 is in turn pivotally attached at #15 to the swinging drop link #11 at its inboard end and acts as the main fulcrum.

This swinging drop link #11 is pivoted to the main frame at #56. The outer end of the main lift link #10 is pivotally attached to the heel section #2 of the load carrying platform by the pin #12. This lever system comprises the main lifting mechanism and controls the vertical loci motion position f (refer Figures 3,4,S& 6) of the load carrying platform.

The following linkage controls the horizontal orientation of the platform. The levelling link #14 is also pivotally attached at #15 to the swinging drop link #11 and the extreme end is pivotally connected to the levelling ram #16 by the rod eye at point #17. The levelling ram is connected to the main frame at #18. The levelling link #14 is extended and carries a second control link #19 which extends to and is pivotally mounted at #20 to the heel section #2 of the load carrying platform, thus completing the parallelogram (refer Figures 3, 4, 5, & 6) that maintains the orientation of the load carrying platform #2, #3 & #4 to the levelling link #14. Any deviation from the true horizontal can be corrected by extending or retracting the levelling ram #16. The relative compensatory movements are depicted in Figure 1 as d and 264708 Referring to Figure 1. The outer toe section #4 constitutes a ground sensing device and is so constructed and pivoted that its centre of gravity makes the toe section move to position a offering a barrier to prevent wheeled loads from running off the platform when the toe #4 is suspended above the ground.

When the platform is lowered to the ground the toe section #4 rotates to position b thus lowering the wheel barrier and operating an inhibiting device to prevent the gravitational inclinometer from operating the levelling ram #16 thus rendering a stable platform.

The relative position of the pivot is such that when the middle foot section #3 is raised to the docking position c the toe section #4 is held vertical by gravitational action.

The middle foot section #3 is prevented from involuntarily folding about the hinge pin #21 by a dual purpose locking device located at #g Figure 2 mounted at the inboard corners of #3. A pair of these devices are actuated by the lock release handle #23 and associated push rods #24 and bell cranks #25 to operate them in unison. The details of the dual purpose locking device is illustrated in the Figures 7 & 8. Figure 7 being a view from above and Figure 8 from beneath the middle foot section. The heel section #2 being representational. Referring to Figure 7 the push rod #24 is connected to the extended end of the locking device bell crank #26. The platform locking pin #27 is projected through the housing block #28 into the receiving hole #29 bored in the platform heel section #2 thus preventing all rotational movement about the hinge pin #21 Figure 1. The other end of the locking device bell crank #26 actuates the docking pin #30 which is retracted simultaneously when the locking pin #27 is projected. 64 708 Referring to Figure 8 when the lock release handle #23 is operated through its extreme arc the push rod #24 moves the bell crank #26, retracting the locking pin #27 and simultaneously the docking pin #30 is projected to a position that it can engage the forked catching arm #31 of the docking transport catch and safety lock. A position sensing device #32 is actuated to confirm the locking pin is released and sets the controls snto docking mode.

A sliding hinged plate #33 bridges the gap between the middle foot section #3 and the heel section #2 offering an uninterrupted surface to the load carrying platform and rides over the heel section #2 when the middle foot section #3 is docked. Refer Figure 1.

A docking transport catch and safety lock is mounted on the demountable frame #5 and positioned on each side of the load carrying platform. One of these catches and the operation are depicted in Figures 12 & 13. Refering to Figure 13 the forked catching arm #31 is shown in the released position and awaiting engagement of the platform docking pin #30. The upward movement of the platform rotates the forked catching arm #31 about the pin #34 thus forcing the docking pin #30 to assume the position h thereby rotating the middle foot section and erecting it to a vertical posture as depicted in Figure 12. At the full stroke of the lift ram #7 the safety lock pawl #35 which is of the self locking type engages by gravity, preventing any downward movement of the forked catching arm #31.

A retainer finger #36 prevents the docking pin #30 from escaping the forked catching arm #31 when the full weight of the docked platform is lowered onto the docking transport catch and safety locks. 264708 To undock, the platform is raised again to the full stroke of the lift ram #7 before a low force linear actuator #37 can disengage the safety lock pawl #35 and the load carrying platform be lowered to the working ! position, which approximates Figure 13. Only then can the dockihg pin #30 be retracted and the platform locking pin #27 engaged by returning the lock release handle #23 to its original position.

The orientation of the load carrying platform in relation to 'the support vehicle in the docking mode is controlled by an external positioning device #38 as depicted in Figure 10. This consists of a sliding block #39 that moves via a push rod #40 in a linear motion over a linked pair of adjustable ramps #41. The sliding block carries two sensing devices #42 (in this case micro switches) which sense the beginning and end of the linked ramps #41, which coincides with the required piston position of the levelling ram #16 to effect correct orientation of the load carrying platform for docking.

The orientation of the load carrying platform in relation to the horizontal plane when in the loading position, is controlled by a gravitational inclinometer as depicted in Figure 9 and is attached to the heel section of the platform. Figure 9a is a plan view and Figure 9b is a front elevation of the device. Referring to Figures 9a & 9b, a metallic ball #44 is free to roll in a track #43 that is a segment of a large radiused rim, the axis of which is horizontal. The metallic ball #44 assumes a position, under the influence of gravity, corresponding to the lowest point on the track irrespective of the rotation of the track about its axis. 26 4 70 8 When the ball passes before the proximity sensors #45 which are mounted in each end of the track a control signal is generated that results in operating the levelling ram #16 therefore restoring the load carrying platform to the true horizontal (as depicted in Figure 1, positions d to e) and the gravitational inclinometer to a state of equilibrium. An adjustment by means of slotted mounting holes #46 is provided to obtain the initial orientation of the device in relation to the load carrying platform.

The lock release handle #23 incorporates a detent spring to ensure the handle remains in its pre-set position of either platform locked "working mode" or platform docked "docking mode" A safety device to detect obstructions trapped between the rising platform and platform-well opening is depicted in Figure 11. A flexible but non stretchable tube #47 is fitted to the underside of the platform-well and trims around the well of the demountable frame #5 so as to detect any obstruction #48 in the "nip gap". The device is self testing and resetting. The sealed flexible tube #47 is almost totally filled with an antifreeze aqueous hydraulic solution, that is maintained at a positive pressure and sensed by the normally open low pressure switch #49 energizing the control circuit. When an obstruction #48 (e.g. part of a load or operators foot) is detected, the resulting increase in pressure due to the tube being squeezed operates the normally closed overpressure switch #50 and de-energizes all of the control circuit except for lowering the platform, thus allowing the release of the obstruction. The tube is pressurized by a pneumatic tyre valve #51 and regulated to a pre-set minimum pressure as monitored by the pressure gauge #52. A small bore tubing #53 connects the manifold #54 with the flexible tube #47. 264708 The control circuit logic diagram is depicted in Figure 14 and shows the sequence of the controls and the inter-action of the various components. Control power supply directed by the platform-well safety device when minimum pressure is present, energizes the main circuit. The rise in pressure of the well safety device opens the high pressure switch which de-activates all the control circuit, with the exception of the main lift ram, 'down solenoid'. When no obstruction is detected the control power is available to the rest of the circuit. The 'ground-detect' isolates the platform levelling ram solenoids when activated. When the platform lock is in docking mode, the main lift ram upper limit switch is by-passed, and the power supply from the 'ground-detect' is re-routed through the platform orientation device, energizing the platform ram solenoids. When the platform lock control is in the working mode, the power is routed through the platform inclinometer, controlling the platform level ram solenoids. The electro hydraulic pump power solenoid is only activated when the main lift ram 'up-solenoid' and the platform level ram, solenoids are energized.

Claims (18)

264708 WHAT I CLAIM IS..

1. A goods handling device comprising of a hydraulically powered three part load carrying platform which is side mountable on a support vehicle to allow the loading and unloading of goods from the support vehicle, the said platform being controlled during its elevation and descent in a vertical motion with minimal deviation, while maintaining the said platform in a horizontal aspect, irrespective of the support vehicles posture.

2. A goods handling device according to Claim 1 that is self docking within the extremities of the support vehicle and the components of the load carrying platform are orientated to the support vehicles posture.

3. A goods handling device according to any one of the preceding Claims; in which the vertical movement of the load carrying platform is induced by a first hydraulic ram within a lever system, that imparts a vertical motion to the platform and a second hydraulic ram that imparts a force in the lever system required to maintain the platforms orientation to the support vehicles posture in the docking mode and/or the horizontal plane when in the loading mode.

4. A goods handling device according to Claim 3 comprising a gravitational inclinometer attached to the load carrying platform to sense the orientation of the load carrying platform in relation to the true horizontal plane when the device is in the loading mode and outputting a control signal to an electro-hydraulic valve to control the position of the aforesaid second hydraulic ram. -12- 264708

5. A device according to Claim 4 wherein the gravitational inclinometer a metallic ball is allowed to roll in a non-metallic track which is itself a segment of a large radius rim, the axis of which is horizontal and at right angles to the plane of orientation of the platform in relation to the true horizontal plane.

6. A device according to Claim 4 or 5 where the aforementioned metallic ball remains in a stable position at the lowest point of the segmented track which when said track is rotated about its axis actuates proximity sensors, located near the ends of the segmented track, outputing a sensing signal to a control circuit.

7. A device according to Claim 3 wherein an external monitoring device is mounted adjacent to the aforementioned second hydraulic ram to sense the position of the aforesaid ram, outputting a control signal to the aforementioned electro hydraulic valve as in Claim 4 causing the aforesaid ram to assume a pre-set position, thus bringing the horizontal orientation of the load carrying platform as in anyone of Claims 1,2&3 to coincide with the support vehicle's posture.

8. A device as claimed in any one of Claims 1, 2 & 3 incorporating a dual purpose locking device to set a control circuit in the loading mode and also to prevent the foot and toe of the docking portion of the load carrying platform from involuntarily rising up due to the platform resting on the ground and further to set the control circuit in docking mode to allow the toe and foot portion of the platform to rise into the docking position by means of a protruding pin engaging docking transport catches. -13-

9. A device as claimed in Claim 8 wherein the docking transport catches have a pivoted fork arm that engages on a protruding pin of the dual locking device as in Claim 8 and a safety latch that takes the form of a self locking ratchet pawl resisting release until further upward movement of the pivoted fork arm allows a low force linear actuator to release the aforesaid pawl.

10. A goods handling device as in any one of the above Claims, that has a dual purpose safety and ground sensing device.

11. A device as in Claim 10 wherein the dual purpose safety and ground sensing device takes the form of a drop down toe that raises a barrier to prevent wheeled loads from running off the load carrying platform until the said platform is resting on the ground.

12. A device as in Claim 10 or 11 wherein the dual purpose safety and ground sensing device takes the form of a drop down toe that senses the platform resting on the ground thereby preventing further levelling movement by isolating the output control signal of the gravitational inclinometer as in Claim 4 thus maintaining the platform in a stable condition irrespective of the support vehicles movement on its load, springs.

13. A goods handling device as in anyone of the above Claims, that has a pressure sensitive safety device fitted to the platfcrm deck-well trim of the support vehicle to prevent damage to any obstruction caught in the "nip gap" between the load carrying platform and the platform deck-well. -14- 264708

14. A device as in Claim 13 wherein the pressure sensitive safety device is in the form of a hydraulically pressurised flexible tube that when squeezed or deformed by an obstruction, such as part of the load or a persons foot, will raise the said hydraulic pressure thus isolating the control circuit and preventing further upward and/or levelling movement of the platform until the obstruction is removed.

15. A goods handling device as in any one of the above Claims that has access to a minimum of three sides when lowered to the ground below the support vehicle deck and all four sides when raised to the same level as the support vehicles deck.

16. A goods handling device as in any one of the above Claims that has the physical layout and construction of all the linkages and components such that their function and/or movement is not impaired by the support vehicles architecture nor the support vehicles construction compromised by the goods lifting device.

17. A goods loading device substantially as herein described with reference to the accompanying drawings.

18. A goods handling device as in anyone of the above Claims and having a controlled circuit logic as depicted in Figure 14. Signed Lyal H.Barrett. 10th October 1995. Revised and signed Lyal H.Barrett. 3rd July 1998. ~15" END OF CLAIMS