Mobile hand truck having a detachable load craddle

Abstract

The present invention relates to a mobile hand truck having a detachable load craddle movably thereon and operatively connected to a screw jack. The screw jack is disposed within the frame structure of the hand truck and is adapted to raise and lower the detachable load craddle relative to the frame structure of the hand truck.

Description

The present invention relates to mobile moving and handling devices, and more particularly to devices known and referred to as hand trucks.

BACKGROUND OF THE INVENTION

Hand trucks have long been used as a means to easily and conveniently move large and ungainly objects, particularly furniture and appliances. Although such hand trucks have generally performed quite well on level surfaces, certain difficulties are commonly encountered when there is an abrupt appreciable change in elevation such as occurs in moving from a loading ramp to an elevated truck bed. In such a situation, it is common practice to manually lift the entire hand truck and load, and deposit the same on the truck bed, or to simply manually lift the load itself and deposit it on the truck bed. In either case, the manual lifting normally calls for several individuals who must exert a substantial effort in manually lifting the load. Moreover, with larger and ungainly objects, the individual must exercise a great deal of care in lifting and placing the load, so as to maintain sufficient control over the load throughout the lift until placed down.

SUMMARY OF INVENTION

After much research and study into the above problems, the present invention has been devised and presents a mobile hand truck having a movably mounted detachable load craddle associated therewith, and a screw jack operatively connected with said detachable load craddle for raising and lowering the same relative to said hand truck. In using the hand truck of the present invention, the load carrying detachable load craddle may be elevated where there is an appreciable change in elevation and placed on the elevated surface without requiring manual lifting. Also, once the load craddle is elevated to the height of the elevated surface and placed thereon, the entire load craddle may be detached from the hand truck. Once on the elevated surface at any appropriate time the hand truck may once again receive the detachable load craddle and/or load associated therewith and the load may once again be moved to another desired location.

It is, therefore, an object of the present invention to provide a hand truck having a movable mounted detachable load craddle operatively connected to an elevating means, whereby the detachable load craddle may be raised to an elevated position and detached from the hand truck.

A further object of the present invention is to provide a hand truck having an easily detachable load craddle associated therewith.

Another object of the present invention is to provide a mobile hand truck having a screw type jack structure associated therewith and operatively connected to said detachable load craddle.

More particularly, a further object of the present invention is to provide a mobile hand truck having a frame structure with a detachable load craddle movably mounted thereon wherein said detachable load craddle includes a detachable securing means that normally encompass said frame structure and confine said load craddle thereabout while allowing said load craddle to move back and forth therealong.

Still a further object of the present invention is to provide a mobile hand truck having an elevatable load craddle incorporated therein, wherein the total structure is sturdy, simple to construct, and relatively inexpensive.

Other objects and advantages of the present invention will become apparent and obvious from a study of the following description of the accompanying drawings which are merely illustrative of the present invention.

IN THE DRAWINGS:

FIG. 1 is a perspective view of the hand truck of the present invention, as viewed from the front and to one side, showing the detachable load craddle detached therefrom and spaced forwardly thereof;

FIG. 2 is a perspective view of the mobile hand truck of the present invention, viewed from the rear and to one side thereof, showing the detachable load craddle attached to the hand truck and slightly elevated thereon;

FIG. 3 is a perspective view of the hand truck of the present invention, viewed from the front and to one side, with the detachable load craddle attached thereto and shown in both a normal lowered position (solid lines) and an upper elevated position (dotted lines); and

FIG. 4 is a perspective view of the load craddle, viewed from the front and to one side, with said load craddle being modified to include a pair of wheels about the lower portions thereof which make the load craddle itself mobile.

With further reference to the drawings, the mobile hand truck of the present invention is shown therein and indicated generally at 10. The hand truck 10 basically comprises a frame structure indicated generally at 12, the frame structure including a pair of laterally spaced rigidly constructed side frames 14.

Each side frame 14 includes a thin elongated flange rail 16 fixed to opposite edges thereof and generally extending the full length thereof.

The side frames 14 are held in fixed relationship relative to each other by a plurality of generally vertical spaced cross reenforcing members 18, the reenforcing members being welded or secured by other suitable means about their outer ends to the inner sides of said frames 14.

Formed about the top of each side frame 14 is a generally semi-circular hand grip 20 that enables an individual to support and push the entire hand truck 10.

Mobility is given the hand truck 10 by the presence of a transverse axle 22 that is disposed transversely the lower portions of the side frames 14. Rotatively mounted to each end of the axle 22, outside the respective side frame 14, is a ground or surface engaging wheel 24.

Fixed to the flange rails 16 adjacent the wheels 24 is a pick-up and support plate 25. As seen in the drawings, particularly FIG. 1, the pick-up and support plate 25 is disposed about a lower end of the hand truck 10 and is adapted to engage the ground or support surface to stablize the entire hand truck in an upright non-use position.

The hand truck 10 further includes a detachable load craddle indicated generally at 26, the load craddle when attached to the frame structure 12 of the hand truck being adapted to move up and down relative thereto. Viewing the load craddle 26 in greater detail, it is seen that the load craddle basically comprises a generally flat back 28 having a pair of guide rails 34 fixed about the back outer edges thereof. The guide rails 34 are disposed in parallel relationship relative to each other and are laterally spaced so as to engage the outer edge of the flange rails 16 and maintain the load craddle about the front surface of the hand truck 10.

As shown in FIG. 3 of the drawings, the load craddle 26 is designed to support a load such as the box B. In order to support a load, the load craddle is provided with a bottom support plate 30 that extends at a right angle from the plane of the back 28 and is particularly disposed about the lower edge thereof. Vertically spaced from the bottom support plate 30 and extending outwardly from the load craddle in a plane generally parallel to the plane of the bottom support plate 30 is an upper retaining plate 32. It will be appriciated that if very large objects are to be supported by the load craddle 26, then this upper retaining plate 32 could be eliminated and the back 28 extended an appropriate distance.

In order to fully confine the load craddle 26 about the frame structure 12 of the hand truck, the present disclosure provides a structure attached to the load craddle that completely encompasses the side frames 14 of the hand truck but allows the same to move up and down thereon. This encompassing structure comprises a pair of arms 36, each arm being fixed to one side of the load craddle 26 and projecting rearwardly therefrom along the outer sides of a respective side frame 14. The rear most end of each arm 36 terminates closely adjacent the rear edge of a respective side frame 14 and the terminating ends of the arms 36 are adapted to receive a detachable retaining rod 38. The retaining rod 38 is adapted to extend through openings formed within the terminal ends of the arms 36 and is retained therein by pins or other suitable detachable securing means. When attached between the arms 36, the retaining rod 38 normally engages the flange rails running along the rear side of the frame structure 12.

Turning to FIG. 4, the load craddle 26 shown therein has been modified to include a pair of caster type wheels 40, the caster wheels being secured to the underside of the bottom support plate 30 and laterally spaced thereunder which has the effect of giving the load craddle itself mobility. Thus, as modified, the load craddle becomes a mini hand truck.

As previously pointed out herein, the hand truck 10 of the present invention is provided with elvating means indicated generally at 42 which may be operatively attached to the load craddle 26 to raise and lower the latter relative to the hand truck's frame structure 12.

Viewing the elevating means 42 in greater detail, it is seen that a shaft support structure 44 is disposed generally between the side frames 14 and is secured to the upper pair of cross reinforcing members 18 by weldment or other appropriate means. Rotatively journaled within the shaft's support structure 44 is a helical screw shaft 46. Threaded on the helical screw shaft 46 is a follower 50 which is axially movable on the screw shaft in response to the rotation thereof. To rotate the helical screw shaft 46, there is provided a handcrank 48, the handcrank being fixed to the upper end of the screw shaft and extending therefrom in convenient reach of the individual using the hand truck 10.

The follower 50 includes a chain 52 fixed thereto and depending therefrom, as best seen in FIG. 1. The chain 52 includes a chain hook 54 that is adapted to be connected to a connecting bracket (not shown) which is fixed to the back side of the detachable load craddle 26.

Therefore, in use, the load craddle 26 is normally attached to the hand truck 10 and operatively connected to the elevating means 42 by the chain 52. The load craddle 26 is free to slide up and down along the frame structure 12 of the hand truck 10, but normally assumes the lower position (full lines -- FIG. 3). If the individual operator incurs a change in elevation, such as presented by a loading ramp and an elevated truck bed, the individual operator may bring the hand truck to a stop adjacent the truck bed and allow the hand truck 10 to rest in the upright position. Next, the operator may manually crank the crank arm 48 in an appropriate direction to cause the follower 50 to move axially up the helical screw shaft 46. the upward movement of the follower 50, results in the chain 52 and the load craddle 26 being raised accordingly. When the load craddle 26 reaches the height of the elevated surface, the operator stops turning the crank arm and is prepared to move the load craddle and associated load onto the elevated surface. Before detaching the load craddle 26, it is desirable to slightly reposition the hand truck such that the bottom support plate 30 of the load craddle 26 is supported by the elevated surface. Once the load craddle 26 is supported by the elevated surface, then the operator can detach the transverse retaining rod 38 extending between the terminal ends of the arms 36. This operation frees the load craddle 26 from the hand truck 10.

The load craddle 26 is preferably provided with at least one flexible retaining belt 56 which may be secured to the back 28 where the flexible belt may be conveniently fastened around the load being supported and transported. Once the load craddle 26 and associated load has been placed on the particular elevated surface, the load may be further transferred by lifting the hand truck onto the elevated surface and attaching the load craddle 26 thereto. Alternatively, the load craddle modification shown in FIG. 4 may be utilized, and consequently once the load craddle 26 is placed on an elevated surface and detached from the hand truck, the load craddle itself may be pushed from one location to another location.

From the above discussion, it is apparent that the hand truck 10 of the present invention has many advantages over conventional hand trucks. Among the advantages is the detachable load craddle 26 and the incorporation of elevating means 42 which allows the load craddle to be raised to an elevated surface and detached from the hand truck. The incorporation of a detachable load craddle and means to raise and lower the same in a hand truck presents very useful features that enable large and ungainly loads to be easily transferred from one location to another location where there are substantial abrupt differences in elevation between the two locations.

The terms "upper," "lower," "forward," "rearward," etc., have been used herein merely for the convenience of the foregoing specification and in the appended claims to describe the mobile hand truck having a detachable load craddle and its parts as oriented in the drawings. It is to be understood, however, that these terms are in no way limiting to the invention since the mobile hand truck having a detachable load craddle may obviously be disposed in many different positions when in actual use.

The present invention, of course, may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range are intended to be embraced herein.

Claims

I claim:

1. A mobile hand truck comprising: a frame structure including a pair of laterally spaced side frame members; a wheel means mounted to said frame structure; a detachable load cradle movably mounted on said frame structure and including a back slidably mounted on one side of said frame structure, said load cradle including a pair of laterally spaced arms fixed about the outside edges thereof and extending rearwardly therefrom, said arms being particularly spaced greater than the width of said side frame members as to extend adjacent the outer sides thereof and having a length greater than the width of said side frame members such that the rear terminal ends of said arms normally project past the rear edge of said side frame members; detachable securing means associated with said load cradle for detachable securing the latter to said frame structure, said detachable securing means including a transverse rod detachably secured to the rear terminal ends of said arms and normally engaged with the rear side of said side frame members so as to hold and confine said load cradle against the front side of said frame structure, whereby said load cradle may be completely detached and separated from said frame structure by detaching said transverse rod from said arms; elevating means disposed on said frame structure; and means for operatively interconnecting said elevating means with said load cradle whereby said load cradle may be raised and lowered relative to said frame structure by actuating said elevating means.

2. The mobile hand truck of claim 1 wherein said elevating means comprises: a screw jack rotatively mounted within said frame structure and including a support structure fixed within said hand truck frame structure, a helical screw shaft rotatively mounted within said support structure; and a hand crank fixed to one end of said helical screw shaft and operative to rotate the same within said support structure; and a follower axially movably on said screw jack and operatively connected to said means interconnecting said elevating means with said detachable load cradle whereby axial movement of said follower about said screw jack is operative to raise or lower said load relative to said frame structure.

3. The mobile hand truck of claim 2 wherein said means interconnecting said elevating means and said detachable load cradle comprises a chain fixed to said follower and depending therefrom where the opposite end thereof includes means for attaching said chain to said detachable load cradle.

4. The mobile hand truck of claim 1 wherein said detachable bad cradle includes a bottom support plate and a top retaining plate, said support and retaining plates extending from said back plate of said load cradle and generally lying in parallel planes which generally extend perpendicularly to the plane of said back.

5. The mobile hand truck of claim 4 wherein said detachable load cradle further includes a pair of laterally spaced guide rails fixed to said back of said load cradle and extending therefrom adjacent the outer sides of said frame structure, whereby said guide rails tend to maintain said load cradle in alignment with the frame structure of said hand truck.

6. The mobile hand truck of claim 5 wherein rolling means are provided on the underside of said bottom plate of said load cradle whereby said load cradle may be moved from one location to another with ease.

7. The mobile hand truck of claim 6 wherein said frame structure comprises a series of spaced apart cross members interconnected between said side frames members to hold the latter in fixed relationship relative to each other; and hand gripping means disposed on one end of each side frame.

8. The mobile hand truck of claim 6 wherein said detachable load cradle further includes a flexible holding belt fixed on one side thereof and adapted to encompass an object loaded on said load cradle and to fasten to said load cradle on the opposite side thereof so as to hold and retain the loaded object.