Patent Application
20110243696
1. Field of the Invention
The invention relates in general to the field of hand trucks for use in lowering, raising and transporting heavy items.
2. Description of the Related Art
When beer kegs and other heavy beverage containers are delivered to bars, restaurants and liquor stores, they often need to be raised into delivery trucks and then lowered back down to ground level upon arrival. In order to do this, the kegs are typically lifted and lowered down by a particularly strong person, or the truck is provided with a loading ramp of one type or another. Unfortunately, it is not always possible to use a loading ramp due to cost or to the space available at a drop-off location. Additionally, lowering kegs manually can be strenuous and dangerous for the person doing the lowering. Likewise, lifting kegs manually can also be very strenuous and dangerous for the person doing the lifting. A full keg of beer typically weighs between about 130 and about 170 pounds, so lifting and lowering a keg from a height of a truck (typically as high as about 68″) without a ramp can be a challenging task to accomplish without damaging the keg or injuring the worker.
Another attempted solution to the problem of transporting and delivering heavy items has been a hand truck that uses mechanical elements to provide controlled lowering of a platform. For example, mechanical elements that enable controlled lowering of a platform may comprise a pneumatic cylinder or other resistance device. With these devices, placing a heavy object on the platform when the platform is in a raised position will cause the platform to slowly descend. However, hand trucks that use resistance-based techniques to lower a platform supporting a heavy object only attempt to address half of the problem—lowering a heavy object from the height of a delivery truck. Notably, these hand trucks fail to adequately provide a solution to the problem of raising heavy objects from ground level to a shelf or truck height. The inability to both raise and lower heavy objects is a significant drawback to using hand trucks with resistance-based lowering techniques in the beer-keg and beverage transportation business. Furthermore, hand trucks utilizing resistance-based lowering techniques are usually biased with the platform in an elevated position, allowing the platform to be lowered only when a heavy object is placed on it. The inability for a hand-truck operator to easily control the height of the movable platform is yet another drawback that limits the effectiveness of hand trucks with resistance-based lowering techniques.
Thus, it is desirable to provide a relatively simple and inexpensive device that allows a person to raise and lower a heavy object, such as a full keg of beer, between a height of a raised position such as a truck loading surface and a ground surface. Such a device is preferably configured to raise and lower heavy objects at a controlled rate.
According to one embodiment, a powered hand truck comprises a frame having a top portion, a bottom portion, and a longitudinal axis extending between the top portion and the bottom portion. The powered hand truck may also comprise at least one handle mounted to the frame adjacent to the upper portion, a pair of wheels attached to the frame adjacent to the bottom portion, and a platform having a substantially planar upper surface that is oriented substantially perpendicular to the longitudinal axis of the frame. In this embodiment, the platform is configured to move axially along the longitudinal axis while maintaining the perpendicular orientation of the platform.
In one embodiment, the powered hand truck further comprises a winch motor configured to provide a force that enables the platform to be raised and lowered. A battery may be used to power the motor. A chain and sprocket system may be used to transfer available torque from the winch motor to a vertical force that enables controlled movement of the platform. For example, in one embodiment, the powered hand truck may be configured to lift and lower a weight of up to about 170 pounds between a ground surface and a height of up to about 68″ at a controlled rate.
According to another embodiment, a raising and lowering device comprises at least one vertical frame member having a pair of wheels mounted to a bottom portion thereof, and at least one handle mounted to the at least one vertical frame member and extending rearwardly from the frame member. The device may further include at least one stabilizing leg mounted to the bottom portion of the frame member and extending forwardly to provide support for the device. In this embodiment, a generally planar platform is movably attached to the vertical frame member. The platform extends forwardly from the at least one frame member and is configured to move vertically along the vertical frame member. The handle may comprise controls to allow the hand-truck operator to control the movement of the platform.
In another embodiment, a method of vertically moving a heavy object between a height and a ground surface comprises placing the object on a platform that is vertically movable on a hand-truck frame. The method further comprises pressing a switch to activate a winch motor, wherein pressing the switch enables raising and lowering of the platform.
Having thus summarized the general nature of the invention, certain preferred embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein having reference to the figures that follow, of which:
With reference to the attached figures, a powered hand truck with raising and lowering capability will now be described. The hand truck of the preferred embodiments generally includes a movable platform which can support a heavy object and which can be raised to a desired height or lowered to a ground surface at a controlled rate under direction of a hand-truck operator.
In the illustrated embodiment of
In the illustrated embodiment of
The upper portion 34 of the frame generally comprises a handle 50 and an upper cross plate 42. The handle 50 may comprise controls that enable the hand-truck operator to control the vertical movement of the platform 20. In other embodiments, these controls may be located elsewhere on the powered hand truck 10. Also, the handle 50 may be rigidly attached to the upper portion 34 of the frame 30 and extend rearward. The handle 50 may comprise any suitable material, and may be attached to the frame in any suitable manner. For example, the handle 50 may comprise sections of steel tubing welded to the frame 30. Although the illustrated embodiments show the powered hand truck with one handle, the skilled artisan will recognize that more handles could alternatively be provided.
The upper cross plate 42 may connect and extend across the vertically-extending side members 44 and central rods 46. In addition, the upper cross plate 42 may comprise steel and be welded to the frame 30. The upper cross plate 42 thereby increases the structural integrity of the frame 30. In addition, a sprocket housing 112 may be connected to the upper cross plate 42. The sprocket housing 112 comprises a sprocket that facilitates movement of the chain 100.
A connecting plate 120 may be configured to couple the platform 20 with the chain 100 and engage the central rods 46 of the frame 30. One end of the chain 100 may be attached to the connecting plate 120, and the tension in the chain 100 transmits a vertical force that enables the platform 20 to move vertically. For example, the chain 100 may be connected to the connecting plate 120 using a sprocket system. In addition, the connecting plate 120 may engage the central rods 46 of the frame 30. By engaging the central rods 46, the connecting plate 120 is guided along a fixed vertical path, which enables the controlled movement of the platform 20 along the fixed vertical path. In addition, the connecting plate 120 may include roller wheels that may be used to facilitate the motion of the connecting plate 120 along the central rods 46. Furthermore, a lubricant, such as an oil, may be used to reduce friction between the connecting plate 120 and/or roller wheels and the central rods 46, thereby improving efficiency and reducing wear.
In one embodiment, the platform 20 is about 19″ wide by about 19″ deep, and is made of a sufficiently rigid material that enables the platform 20 to support the weight of a desired load in a cantilevered manner. The platform 20 may also comprise a textured, knurled, patterned, or roughened surface to increase friction between the platform surface and the keg or other load placed thereon.
As shown in
As illustrated in
The rear wheels 62 mounted to the base of the powered hand truck 10 can generally be any size or type. In the illustrated embodiment, the rear wheels 62 are shown spaced rearward from the base of the powered hand truck 10 so as to provide additional stability, thereby preventing the powered hand truck from tipping backwards too easily.
Also shown in
In one embodiment, the winch motor 96 is configured to receive DC electrical power from the battery 94. In addition, the winch motor 96 may be coupled to one end of the chain 100. For example, a system of one or more sprockets (not pictured) may be used to couple one end of the chain 100 to the winch motor 96. The torque output of the winch motor 96 enables the chain 100 to raise and lower the platform 20. In a preferred embodiment, the winch motor 96 is selected to be capable of lifting a load of at least 200 pounds. For example, the winch motor 96 may be the Northern Industrial Tools Electric Utility Winch Model No. 400195A. In one embodiment, one or more sprockets may be used to couple the chain 100 to the winch motor 96. In view of the present disclosure, it will be understood by a skilled artisan that as the chain 100 is wound up, the platform 20 will be raised, and as the chain 100 is unwound, the platform 20 will be lowered. In addition, in view of the present disclosure, a skilled artisan will understand that in alternative embodiments, various combinations of different types of batteries and electric motors may be used to engage the chain 100 to lift and lower the platform 20.
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A skilled artisan will appreciate that the platform 20 may not be positioned above its maximum height or below ground level. Thus, in one embodiment, the powered hand truck may be provided with an override mechanism whereby if the switch is in a position to cause the platform 20 to move downward, and the platform 20 has reached ground level, the switch will automatically switch to its off state. Alternatively, the powered hand truck may be provided with an override mechanism whereby if the switch is in a position to cause the platform 20 to move upward, and the platform 20 has reached its maximum height, the switch will automatically switch to its off state.
In alternative embodiments, the powered hand truck may include separate up and down buttons to control the ascent and descent of the platform 20. For example, the powered hand truck may include a dedicated up button that can be pressed and held to cause the platform 20 to be raised. Likewise, the powered hand truck may include a dedicated down button that can be pressed and held to cause the platform 20 to be lowered. When the operator is not pressing and holding the up or down button, the platform 20 may remain stationary, thereby preventing inadvertent movement of the platform 20. In addition, the separate up and down buttons may be located far apart. For example, the up button may be located on one side of the handle 50, while the down button is located on the other side of the handle 50. In addition, to prevent confusion between the up and down buttons, the up and down buttons may be different colors.
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In one embodiment, as shown in
When the platform 20 is in the raised or lowered positions, the powered hand truck 10 will be stably supported by the stabilization legs 36 and the rear wheels 62. The powered hand truck 10 can then be moved forwards or backwards while remaining vertically oriented, so as to position the hand truck in a desired location relative to the truck from which kegs may be lowered. In embodiments in which a brake is provided, it can be set to prevent the powered hand truck 10 from rolling from the desired position. Once a keg is lowered on the platform 20 to the down position, the powered hand truck 10 can be operated in a conventional manner by tipping the top portion of the powered hand truck 10 rearward, and rolling the powered hand truck 10 on the rear wheels 62. When the powered hand truck 10 is tipped rearward, a keg placed on the platform will lean against the support bar 82. If desired, a keg or other load can be strapped to the support bar 82 to prevent the load from undesirably shifting on the platform.
In one embodiment of a method of use, the powered hand truck 10 can be positioned on the ground adjacent to a truck loading surface, and oriented upright. The platform 20 can then be raised to the desired height by operating the switch 52. The powered hand truck 10 can then be moved forwards to a position in which the platform 20 overlaps a portion of the truck loading surface. In one embodiment, the platform 20 can be raised to a position substantially above a truck loading surface in order to receive a keg on an upper stack. Once the platform is in the desired position, a keg can be loaded onto the platform, and the platform can be lowered by operating the switch 52. In a situation where the platform 20 overlaps the truck loading surface, the powered hand truck 10 can be moved backwards while remaining in an upright position. Once the path between the platform 20 and the ground is clear, the platform 20 can be lowered completely to the ground, and the keg can be unloaded at ground level.
As will be clear to the skilled artisan in view of the present disclosure, the system components need not be identical to those shown in the illustrations. For example, while the powered hand truck has been described as using a chain to transmit force from the motor to the platform, the skilled artisan will appreciate how to modify the system using alternative load-bearing elements, such as a rope or wire. In addition, although the powered hand truck has been described with respect to an electric winch motor, the skilled artisan will appreciate how to modify the system using other motors, such as a winch motor powered by hydraulic, pneumatic, or internal combustion drives.
Although certain embodiments and examples have been described herein, it will be understood by those skilled in the art that many aspects of the methods and devices shown and described in the present disclosure may be differently combined and/or modified to form still further embodiments. Additionally, it will be recognized that the methods described herein may be practiced using any device suitable for performing the recited steps, and the devices described herein can be used in other applications beyond those described. Such alternative embodiments and/or uses of the methods and devices described above and obvious modifications and equivalents thereof are intended to be within the scope of the present disclosure. Thus, it is intended that the scope of the present invention should not be limited by the particular embodiments described above, but should be determined only by a fair reading of the claims that follow.
