Hand truck

Abstract

A hand truck having a frame two short and two long sides; a wheel and axel assembly attached to the frame; a lifting assembly extending between the two short sides; said lifting assembly comprising a frame center pole rail having an attached gear rack, a gear box movably attached to the center pole, said gear box including, a toothed that meshes with the gear rack, a worm gear having a drive shaft that meshes with the toothed pinion, wherein rotation of the drive shaft causes the worm gear to drive the pinion along the gear rack; a lift bracket attached to the gear box comprising a receiving plate with at least one slot; and at least one removable lift platform comprising a platform plate with at least one key that is securely receivable into the slot; wherein the gearbox is drivable using a power supply supplied by a user.

Description

In the present invention it is critical that the gear box 36 uses a rack and pinion system in order to prevent unwanted back-drive of the gear box 36 caused by gravity acting on the load. Because there is no unwanted back-drive, the system of the present invention does not require a manual brake or electromagnetic brake in order to keep the load in place once lifted.

In a preferred embodiment, the present invention does not include a drive motor attached to the hand truck 1, as is commonly found in the prior art. The preferred embodiment of the present invention utilizes an external drive motor that is supplied by the user, such as a cordless power drill 100 or the like. A rotating throttle handle 102 controls the portable electric drill trigger by a throttle control cable 104 affixed to portable drill energizing forward or reverse motion to worm gear box module (not shown).

Removable lifting platforms 150 are designed to be removably attached to lift brackets 120 that are attached to the gear box 36. The lift bracket has a receiving plate 122. The receiving plate 122 preferably has at least one, more preferably at least two and most preferably at least four slots 124 to receive a like number of keys 152 from a lifting platform 150.

In a preferred embodiment, the lifting platform 150 comprises a platform plate 151 having the at least one, more preferably at least two and most preferably at least four keys 152 which simple slide into the receiving plate 122 attached to the gear box 36.

In order to keep the lifting platform 150 in place once the keys 152 are inserted into the receiving plate slots 124, a locking mechanism 126, such as a plunger spring loaded slide, passes through both the receiving plate 122 and at least one pin receiving aperture 154 in the platform plate 151 and locks the two together.

In a preferred embodiment, there are straps 160 used to hold lifted objects securely in place. In a preferred embodiment, two ratchet straps 161 are attached to the left side of the hand truck 1 with D-rings 162 for the hooks of the straps 161 to engage to the right side of the hand truck 1.

In a preferred embodiment, there is a strap lock 170 that pivotally locks and unlocks the straps 160. Preferably, located at one end of the strap axis is a toothed/ratchet gear 172. A tang 174 is pivotally attached to an end of the lift bracket 120 near the toothed gear 172 and is rotatably engagable/unengagable with the toothed gear 172. When engaged, the tang 174 locks the toothed gear 172, and consequently the strap 162, into place. When the tang 174 is disengaged from the toothed gear 172, then the strap 162 is free to be wound or unwound.

In a preferred embodiment, there may be upper and lower half moon glide brackets 126 attached to the receiving plate 122. The glide brackets 126 provide upper and lower support to the receiving plate 122 as the gear box 36 is traveling up and down the rail 32.

Located on the back side of the lifting brackets 120 are at least one glide 128 affixed to each outer corner of the bottom of the lifting brackets 120. These glides 128 allow the lifting brackets 120 to remain stable and glide with ease up and down the front of the dolly frame 10. In an alternate embodiment, the glides 128 may be made to rotate by means of a sleeve or a bearing.

In a preferred embodiment, a cordless drill chuck 51 simply slides onto the gear box drive shaft 50. The drill chuck 51 is typically tightened by hand, however square nut, hex head, or keyed head could be attached to the distal end of the drive shaft 50. This would allow the drill to be fastened to the drill with a socket attachment held in the drill chuck 51.

In order to comfortably steer the hand truck 1 according to the present invention, located just above a mid-point in the long sides 14 of the frame 10 are at least one, preferably two handles 60. Preferably, these are adjustably attached to the long sides 14 such that they can be easily placed and locked into place at a comfortable location for the different users.

There are various lifting platforms 150 that may be used with the hand truck 1 of the present invention. First, all of the various embodiments of lifting platforms 150 that are use with the present invention have a platform plate 151 with at least one, more preferably at least two and most preferably at least four keys 152 and at least one pin receiving aperture 154. In a first embodiment of the lifting platform 150, attached at a bottom edge of the platform plate 151 is a lift platform 155. In a second embodiment of the lifting platform 150, attached at a top end and a bottom end of the platform plate 151 is a pair of lift bumpers 156. In a third embodiment of the lifting platform 150, attached at a bottom edge of the platform plate 151 is a pair of lift cradles 157.

In a most preferred embodiment, the hand truck 1 further includes a wheeled kick-out 180. Preferably the kick-out 180 is pivotally attached to about a mid-point of the long sides 14 of the frame 10. More preferably, the kick-out 180 also features a spring biased locking mechanism 190 for locking the kick-out 180 to the axel rod 20 when not in use.

The preferred embodiment of the invention is described above in the Drawings and Description of Preferred Embodiments. While these descriptions directly describe the above embodiments, it is understood that those skilled in the art may conceive modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations that fall within the purview of this description are intended to be included therein as well. Unless specifically noted, it is the intention of the inventor that the words and phrases in the specification and claims be given the ordinary and accustomed meanings to those of ordinary skill in the applicable art(s). The foregoing description of a preferred embodiment and best mode of the invention known to the applicant at the time of filing the application has been presented and is intended for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in the light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application and to enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. A hand truck for moving heavy or bulky objects comprising:

a frame having two short sides and two long sides;

a wheel and axle assembly attached to the frame;

a lifting assembly located at an intermediate position between the two long sides and extending between the two short sides; said lifting assembly comprising;:

a frame center pole rail having a gear rack attached thereto;

a gear box movably attached to the frame center pole rail, said gear box including:

a toothed pinion, located in the movable gear box, mounted on a shaft in the gear box and meshing with the gear rack of the frame center pole rail;

a worm gear that meshes with the toothed pinion, the worm gear including a drive shaft, wherein rotation of the drive shaft causes the worm gear to drive the pinion along the gear rack;

a lift bracket comprising a receiving plate with at least one slot; and

at least one removable lift platform comprising a platform plate with at least one key that are is securely receivable into the at least one slot of the lift bracket receiving plate, wherein the removable lift platform further comprises a pair of lift members, with one lift member attached at a top end of the platform plate and the other lift member attached at a bottom end of the platform plate; and

an aperture located in the platform plate and a locking mechanism located on the lift bracket receiving plate and receivable by the aperture located in the platform plate;

wherein rotation of the drive shaft moves the gear box along the frame center pole rail.

2. The hand truck according to claim 1 wherein the gearbox is drivable using a power supply supplied by a user.

3. The hand truck according to claim 1 wherein the pair of lift members includes a pair of lift bumpers.

4. The hand truck according to claim 1 wherein the pair of lift members includes a pair of lift cradles.

5. The hand truck according to claim 4 further comprising:

a second removable lift platform comprising a platform plate with at least one key that are securely receivable into the at least one slot of the lift bracket receiving plate, wherein the removable lift platform further comprises a pair of lift bumpers, with one lift bumper attached at a top end of the platform plate and the other lift bumper attached at a bottom end of the platform plate; whereby the hand truck can change between a pair of bumpers and a pair of cradles.

6. A hand truck for moving heavy or bulky objects comprising:

a frame having two short sides and two long sides;

a wheel and axle assembly attached to the frame;

a lifting assembly located at an intermediate position between the two long sides and extending between the two short sides; said lifting assembly comprising;

a frame pole rail having a gear rack attached thereto,

a gear box movably attached to the frame pole rail, said gear box including:

a toothed pinion, located in the movable gear box, mounted on a shaft in the gear box and meshing with the gear rack of the frame pole rail

a worm gear that meshes with the toothed pinion, said worm gear including a drive shaft, wherein rotation of the drive shaft causes the worm gear to drive the pinion along the gear rack;

a lift bracket comprising a receiving plate with at least one slot and at least one aperture; and

at least one removable lift platform comprising a platform plate with at least one key that are securely receivable into the at least one slot of the lift bracket receiving plate and a locking mechanism receivable by the aperture located in the platform plate; wherein the platform plate further includes a pair of lift bumpers attached at a top end and a bottom end of the platform plate;

wherein the gearbox is drivable using a power supply supplied by a user.

7. A hand truck for moving heavy or bulky objects comprising:

a frame having two short sides and two long sides;

a wheel and axle assembly attached to the frame;

a lifting assembly located at an intermediate position between the two long sides and extending between the two short sides; said lifting assembly comprising;

a frame center pole rail having a gear rack attached thereto,

a gear box movably attached to the frame center pole rail, said gear box including:

a toothed pinion, located in the movable gear box, mounted on a shaft in the gear box and meshing with the gear rack of the frame pole rail,

a worm gear that meshes with the toothed pinion, said worm gear including a drive shaft, wherein rotation of the drive shaft causes the worm gear to drive the pinion along the gear rack;

a lift bracket comprising a receiving plate with at least one slot and at least one aperture; and

at least one removable lift platform comprising a platform plate with at least one key that are securely receivable into the at least one slot of the lift bracket receiving plate and a locking mechanism receivable by the aperture located in the platform plate, wherein the removable lift platform further includes a pair of lift cradles attached at a top end and a bottom end of a platform plate;

wherein the gearbox is drivable using a power supply supplied by a user.

8. A hand truck, comprising:

a frame having a first end and a second end;

a wheel and axle assembly attached to the first end of the frame;

a gear rack supported by the frame and extending between the first and second ends of the frame, the gear rack including a plurality of gear teeth spaced along a length of the gear rack;

a gear box movably attached to the gear rack, said gear box including a worm gear mechanically associated with the gear teeth of the gear rack so that rotation of the worm gear relative to the gear teeth causes the gear box to move along a length of the gear rack;

an attachment coupled to the worm gear and adapted to receive a portable, removably attachable motor to rotate the worm gear; and

a lifting platform coupled to the gear box and moveable along the length of the gear rack with the gear box;

wherein the hand truck does not include a drive motor attached to it; and

wherein the worm gear is positioned on a first side of the gear rack and the lifting platform is positioned on a second side of the gear rack.

9. The hand truck of claim 8, and further comprising a drive shaft, wherein said portable removably attachable motor is a power drill and said drive shaft is adapted to receive a drill chuck to power said lifting assembly to move said lifting platform.

10. The hand truck of claim 9, wherein the power drill is a cordless drill.

11. The hand truck of claim 9, wherein said drive shaft is arranged to rotate the worm gear to lift said lifting assembly.

12. A system including the hand truck of claim 8, wherein said lifting platform is a first lifting platform having a horizontal platform plate and the system further comprising a second lifting platform attachable in place of said first lifting platform, said second lifting platform having at least one cradle adapted for receiving a cylindrical object in said cradle.

13. A hand truck, comprising:

a frame having a first end and a second end;

a wheel and axle assembly attached to the first end of the frame;

a lifting platform moveable along a length of the frame; and

a lifting assembly arranged to move said lifting platform along the frame;

wherein the hand truck does not include a drive motor attached to it;

wherein the lifting assembly includes an attachment;

wherein said attachment is adapted to receive a portable removably attachable motor attached thereto to power said lifting assembly to move said lifting platform; and

wherein a rotatable throttle control handle is attached to the frame and controls the portable removably attachable motor by a throttle control cable affixed to the portable removably attachable motor.

14. A hand truck system, comprising:

a hand truck having:

a frame having a first end and a second end;

a wheel and axle assembly attached to the first end of the frame;

a lift bracket moveable along a length of the frame;

a lifting assembly arranged to move the lift bracket along the frame; and

a first lifting platform attachable to the lift bracket and having a horizontal platform plate; and

a second lifting platform attachable to the lift bracket in place of said first lifting platform, said second lifting platform having at least one cradle adapted for receiving a cylindrical object in said cradle;

wherein the lifting assembly includes a gear rack and a gear box;

wherein said gear rack extends between the first and second ends of the frame;

wherein rotation of the worm gear around an axis of rotation causes the gear box to move along a length of the gear rack;

wherein the first lifting platform is coupled to the gear box and moveable along the length of the gear rack with the gear box; and

wherein the gear box is positioned on a first side of the gear rack and the first lifting platform is positioned on a second side of the gear rack.

15. The hand truck system of claim 14, and further comprising a strap to securely hold objects in place on said hand truck.

16. The hand truck system of claim 14, wherein the cylindrical object is a water heater.

17. The hand truck system of claim 14, wherein the first and second lifting platforms each have a projection arranged to be received within a slot of the lift bracket.