"HYBRID POWERED LIFTING SYSTEM"

TECHNICAL FIELD

The present application relates to a system for adding powered lift to an otherwise manually actuated hydraulic jack, such as common pallet jacks, providing a hybrid combination of both systems that can be applied, either manual or powered lifting.

BACKGROUND ART

The manual pallet jack was invented in the 1930's and the first units became commercially available soon thereafter. Pallet jacks have been modified for purposes other than for lifting and moving pallets such as with platforms or other attachments and including more recently hitching connections that allow it to connect with and move carts for example. A typical jack includes a hydraulic jacking system that supports a frame carrying a pair of forwardly extending forks or other adaptation. The lifting mechanism includes a lift cylinder with an upward pushing lifting rod that connect directly and or through linkages to the frame plus a pump cylinder for providing pressurized hydraulic fluid to the lift cylinder.

Other pallet jack assemblies and related prior art lift devices are shown in the following U.S. patents:

2,049,335 1936-Jul-28 Stephens 2,309,138 1943-Jan-26 Quayle 2,461,212 1949-Feb-08 Hanna 3,462,167 1969-Aug-19 Rateau 2,488,521 1949-Nov-22 Barrett 2,993,703 1961-Jul-25 Paradise 3,118,107 1965-Jun-08 Quale 3,119,627 1964-Jan-28 Klumb 3,286,985 1949-Nov-22 Barrett 2,993,703 1961-Jul-25 Paradise 3,118,107 1965-Jun-08 Quale

3,119,627 1964-Jan-28 Klumb 3,286,985 1966-Nov-22 Edera

3,567,240 1971-Mar-02 Brassington 3,608,922 1971-Sep-28 Best et al 3,701,211 1972-Oct-31 Best 3,757,523 1973-Sep-ll Resuggan 3,775,027 1973-Nov-27 Craft 3,817,546 1974-Jun-18 Suguira 3,843,147 1974-Oct-22 Fredricson 3,940,338 1976-Feb-24 Btyntse, et al. 4,497,501 1985-Feb-05 Kedem

While sit-on powered forklifts had been invented near the turn of the 19 ^th century, being adaptations of small vehicular trucks, manual pallet jacks which were developed later did not lend themselves to being converted to powered locomotion due to the size and weight of the engines available at the time. As a result, pallet jacks with powered locomotion did not become available until the middle of the century as lead acid batteries and electric motors became more available.

In powered pallet moving devices, such powered pallet jacks are generally referred to as "walkies" as you walk behind them, vs. "riders" that have a platform to stand on and fork trucks that are typically sit-down units.

DISCLOSURE OF INVENTION

In more recent years, the market has grown for smaller, less expensive powered walkies that in size and cost sit between fully powered "walkies" and manual pallet jacks. They typically use smaller battery packs that can be removed and charged outside of the machine. They are typically intended for applications that have relatively low duty cycles but where for reasons of improving operator safety or due to tight space or weight constraints, a compact but still powered walkie solution is desirable.

Some such machines are offered with powered hydraulic lifting and some are offered with conventional manual hydraulic lifting.

An advantage of the present invention is that it offers both manual and powered lifting in one compact and low-cost device. It allows a contingency solution of manual jacking if the powered system is inoperable (such as if the battery pack is depleted or due to electrical or electro-mechanical failure). Also, as it is not a new lifting system but attaches to an existing manual pumping system, it is therefore retrofittable to a manual jack that did not originally have a powered lifting system.

These and other features, aspects, and advantages of the present invention will become better understood from the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention a re described below with the reference to the fol lowing accompanying drawings:

Figure 1 is a is a perspective view of a conventional manual jack 10 with the lower portion of the jack handle 80 in a vertical orientation. The manual jack's chassis 70 is shown in addition to the hydraulic jacking system 20.

Figure 2 is the same view of Figure 1 but with the jack handle 80 pivoted down, to simulate the act of pumping, to jack up the pallet jack frame 70. Visible is the hydraulic jacking system 20 comprising the hydraulic pump 30 and hydraulic lift 50.

Figure 3 shows the same manual jack 10 of figure 1 but after it has had the hybrid powered lifting system 100 installed into it. The throttle 170 is shown, added to the top of the handle where the operator can activate various buttons and controls, including the activation of the lifting motor. Also visible nearby the handle throttle assembly is the lift release lever 86 of the original manual jack (10) which is still used to release the lift cylinder and lower the pallet jack frame when the load is to be put back on the ground.

The dashed curved line on Figure 3 represents the pumping action that can be made to the jack handle 80 by the operator even after it has been retrofitted with the hybrid powered lifting system.

Figures 3-4 also show one possible location for the containment of an energy source for the motor assembly 130, most typically a battery pack and most commonly removable and rechargeable. Adjoining the battery pack in this representation is the motor control ler that provides the power to the motor assembly 130 to operate the motor of the hybrid powered lifting system. Note that miscellaneous hardware such as wires, connectors etc. are not shown in the Figures for the sake of simplicity.

Figure 5 is a perspective view of a manual jack 10, shown fitted with a locomotive drive unit for powered moving of the unit. For the operator to control the drive unit, again the handle throttle assembly 170 can be used and further, the battery pack 182 and controller 184 of this drive unit can also be used to power the motor assembly 130 of the hybrid powered lifting system 100, helping to further reduce cost of the overall system.

Figure 6 shows a close up and partially sectioned view of the drive unit shown in Figure 5. The removable battery pack 182 is shown along with the motor controller (which can be a multiple channel output motor controller to control both the drive motor and also the motor assembly Figure 7 is a partially sectioned side view of the manual jack 10. Many of the key components are identified, referenceable from the Glossary of Components at the end of this description. The purpose of this drawing is to illustrate the pivot of the jack handle 80 and how this works as a long lever for a cross shaft that is mounted in the handle assembly mount 88 to push down on the top of the pump piston 32.

This is illustrated because the geometry is important to achieve the desired effect of providing substantial leverage to the operator to manually depress the pump piston 32. All the disclosed alternative designs for the hybrid powered lifting system 100 maintain contact between the cam profile 124 of the camshaft assembly 120 with the top face of the pump piston 32 through the entire stroke range of the handle assembly when pumping manually.

Figure 8 conceptually illustrates the pumping concept as employed in the hydraulic jacking system 20 of a manual jack 10. The components are identified by number. The process is very simply, although as this is prior art and well established prior art (more than 2 million manual jacks are built annually that use this system) there is no need to explain it in detail here.

Figure 9 conceptually illustrates an alternative way of engaging with the pump piston 32, being with the rotating camshaft assembly 120 that has a cam profile with the desired amplitude ... in this illustration the amplitude is shown as "A - B" in the attached image. The rpm of the motor and the length of the stroke can each be adjusted to achieve the required speed to torque output. For example with a given motor, a vertical stroke (amplitude) of (say) 3 mmm will result in a given load lifting capacity and given speed - which will likely vary based on the load. Changing that cam profile for one where A - B = 6mm will approximately double the speed at which the lifting rod wil l travel, but approximately halve the amount of weight it could lift.

Figure 10 is a conceptual image showing the vertical travel of the pump piston 32 as the camshaft assembly 120 rotates. Each image left to right shows 90 degrees of clockwise rotation and the corresponding effect on the pump piston 32. The rotational axis of the camshaft assembly 120 is the same for all stages shown. The rotational axis is described by the cross symbol in the center of the camshaft shown by the circular arrow. The offset of the cam profile changes the distance of the contact point between the camshaft and the pump piston 32.

Starting at the left most stage and moving right, the offset is pointed directly towards the lift piston causing the lift piston to be in the lowered position. The next stage shows the camshaft offset rotated and pointed to the left allowing the lift piston to be in a partially depressed state. The middle stage has the camshaft offset further rotated to point up allowing the piston to move to the up position. The next stage has the camshaft offset further rotated and pointing to the right allowing the lift piston to be in a partially depressed state. The left most stage has the offset rotated in the down position causing the lift piston to be in the lowered position. Considering the proceeding description of how a pallet jack lift piston system works, it should be appreciated that the rotation of the camshaft controls the position of the lift piston, displacement of hydraulic fluid, and vertical movement of a pallet jack.

Testing of the hydraulic jacking system has demonstrated that a stroke length greater than 2.5mm will result in an efficient transfer of the power in (from the motor) to the power out (lifting of the pallet jack's load). Figure 11 shows a closer view of Figure 3, partially sectioned to show the motor assembly 130, camshaft assembly 120 and chain drive power transmission 140, all mounted into the drive and camshaft assembly mount 110 of the jack handle 80.

Figure 12 shows the main components of the present invention exploded, being the manual jack 10, the jack handle 80 with a handle throttle assembly 170 and a battery pack with motor controller 180.

Figure 13 shows one alternative drive approach, being to have one or more externally located motors or motor gearboxes and in this case to drive the camshaft through a right-angle gearbox that connects directly to the camshaft axle 122 of the camshaft assembly 120.

Figure 14 shows another alternative drive approach, being to have a hub motor 134 or hub motor gearbox 135 that gear drives the camshaft assembly 120.

Figures 15-18 show another alternative drive approach, being to have a hub motor 134 or hub motor gearbox 135 that has the cam profile mounted about its own perimeter and then engages with a bearing or other low friction material that is directly mounted to the pump piston 32. Additional linkages are shown in these images that are related to ensuring the bearing maintains contact with the pump piston 32 as the handle lever is pumped.

Figures 19-20 show an adjacent motor 132 or adjacent motor gearbox 133 that connects via a chain and sprockets or belt and pulleys drive transmission 140 to rotate the camshaft assembly 120.

Figure 21 is a perspective view of the preferred hybrid powered lifting system, including an adjacent motor 132 (in this case without gearbox, but could also be with gearing) that drives the camshaft assembly 120 by chain and sprocket.

Figure 22 is a sectioned view of the same assembly. The main reason for this view is to show the construction of the camshaft axle 122 on which is built a cam profile 124, supported on multiple bearings or bushings 126.

Figure 23 is an exploded view of the same camshaft assembly 120 to provide further clarification of this design. It should be noted however that this preferred embodiment and the other example embodiments in figures 13 through 20 are not an exhaustive list of means to achieve the same basic effect, being to have a motor assembly 130 drive a camshaft assembly 120 to engage a pump piston 32 and to be able to maintain contact as the jack handle is pivoted.

Figure 24 illustrates a sectioned perspective view of the hydraulic jacking system 20 of a manual jack 10, while Figure 25 illustrates the same sectioned view for a hybrid powered lifting system 100 engaging with the same hydraulic jacking system 20 on a manual jack so fitted.

Figures 26-28 show side views of a manual pallet jack with the jack handle up and also pivoted down and the handle assembly sectioned.

Figures 29-31 show side views of a manual pallet jack fitted with the preferred embodiment of a hybrid powered lifting system 100 with the jack handle up and also pivoted down and the handle assembly sectioned. Figures 32-33 shows in exploded view the components of a chain driven hub motor 134 design.

Figures 34-35 shows in exploded view the components of a directly connected externally mounted motor-gearbox 137 design.

Figures 36-37 illustrates side section views to show how the cam component works the same way as the connecting cross-tie on a manual jack 10 to engage with the pump piston 32 as the jack handle is pumped manually by the operator.

Figures 38-39 shows in exploded view the components of a gear driven hub motor 134 design.

Figures 40-41 illustrates side section views to show how the cam component works the same way as the connecting cross-tie on a manual jack 10 to engage with the pump piston 32 as the jack handle is pumped manually by the operator.

GLOSSARY OF COMPONENTS

10 MANUAL JACK

20 HYDRAULIC JACKING SYSTEM

30 HYDRAULIC PUMP

32 PUMP PISTON

34 PUMP CYLINDER

36 PUMP RECIPROCATION SPRING

38 PISTON WEAR AND SPRING RETAINING CAP 50 HYDRAULIC LIFT

52 LIFTING ROD

54 LIFTING CYLINDER

70 JACK CHASSIS

72 THRUST PLATE

74 LIFTING ARMS

76 JACK FRAME

80 JACK HANDLE

82 HANDLE SHAFT

84 HANDLE GRIP

86 LIFT RELEASE LEVER

88 HANDLE ASSEMBLY MOUNT

100 HYBRID POWERED LIFTING SYSTEM

110 DRIVE AND CAMSHAFT ASSEMBLY MOUNT

112 DRIVE CHASSIS

114 DRIVE COVER

120 CAMSHAFT ASSEMBLY

122 CAMSHAFT AXLE

124 CAM PROFILE

126 CAM BEARINGS OR BUSHINGS

130 MOTOR ASSEMBLY

132 ADJACENT MOTOR

133 ADJACENT MOTOR GEARBOX 134 HUB MOTOR

135 HUB MOTOR GEARBOX

136 EXTERNALLY LOCATED MOTOR

137 EXTERNALLY LOCATED MOTOR GEARBOX

140 CHAIN DRIVE OR BELT DRIVE POWER TRANSMISSION

142 MOTOR DRIVE SPROCKET OR PULLEY

144 DRIVEN SPROCKET OR PULLEY

146 DRIVE CHAIN OR DRIVE BELT

150 GEAR DRIVE POWER TRANSMISSION

152 MOTOR GEAR

154 INTERMEDIARY GEAR(S)

156 DRIVEN GEAR

170 HANDLE THROTTLE ASSEMBLY

180 MOTOR POWER SOURCE AND CONTROL

182 ENERGY SOURCE SUCH AS BATTERY PACK(S)

184 MOTOR CONTROLLER (SINGLE OR MULTIPLE CHANNEL OUTPUT)