US3844431A

US3844431A - Unloader mechanism for a handtruck

Info

Publication number: US3844431A
Application number: US00361600A
Authority: US
Inventors: B Crawford
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-05-18
Filing date: 1973-05-18
Publication date: 1974-10-29
Anticipated expiration: 1991-10-29

Abstract

An improved unloader mechanism for a two-wheel handtruck utilizes a lever actuated movable load pusher member associated with a load receiving platform to exert a pushing force laterally outward and evenly against a load to assist in unloading the handtruck.

Description

[ Oct. 29, 1974 UNLOADER MECHANISM FOR A 7 12/1969 Gottinger....1.......................

HANDTRUCK Primary Examiner-Robert B. Reeves Assistant ExaminerThomas E. Kocovsky L S m E 51 93 d4 oo m2 m C m u m0 w Mm BC n O t. n e v n P 7 [22] Filed: May 18, 1973 ABSTRACT [21] Appl. No.2 361,600

An improved unloader mechanism for a two-wheel [52] US.

214/511, 280/47 27 handtruck utilizes a lever actuated movable load 51] Int. B62b 1/10 pusher member associated with a'load receiving plat- [58] Field of Search form to exert a pushing force laterally outward and evenly against a load to assist in unloading the hand truck. 4

References Cited UNITED STATES. PATENTS 2,838,193 6/1958 214/511 4 Chums 7 Draw; Figures PATENIEDHCT 29 974 3. 844,431

SHEEI 10F 2 PMENIEDUCTZQ e974 3,844,431

- saw an; 2

This invention relates to handtrucks and more particularly to manually operable, two-wheel handtrucks having lever actuated unloader means.

2. Description of the Prior Art:

The prior art in handtruck unloading mechanisms has included various pusher and roller means adapted to force some point or points of the load away from a handtruck. Quite often the force of the unloader mechanism is directed to only a smallsurface of a load resulting in uneven distribution of force. Such uneven distribution of unloader force frequently topples a bulky load and mars or otherwise damages a heavy load. In the case of handtrucks in common use for han dling bags of fertilizer, cement, feed, etc., conventional unloader mechanismshave heretofore been unsuccessful due to the susceptibility of the bags to breakage when subjected to force over only a very small area of the load. In addition, such conventinal unloader mechanisms have a tendency to topple such a bagged load due to the uneven exertion of force used to effect unloading. As a consequence two men are normally required to load and unload such a handtruck. Some representative prior art patents teaching various tyes of integral handtruck unloading mechanisms include US. Pat. Nos. 652,506, 2,765,090 and 2,649,981.

It is evident that the handtruck unloading mechanisms of the prior art may be improved upon to a significant degree and it is to this end that the invention as shown and described herein is directed.

SUMMARY OF THE INVENTION According to the present invention an improved unloader mechanism for a handtruck mounts the side frames of a conventional handtruck and comprises a pair of spaced elongated support members each having one end pivotally secured to an upper portion of the handtruck side frames. A vertically disposed load pusher member is pivotally secured to the opposite ends of the support members. Such load pusher member may take the shape of a particular load to be loaded and unloaded but is preferably substantially flat. A pair of spaced operator mechanisms movably secure the pusher member to a lower portion of the side frames. A foot actuated lever pivotally secured to the side frames is coupled with each operator mechanism by connecting bar means and includes resilient means communicating between the lever and a side frame such that operation of the foot actuated lever to a downward position causes the operator mechanisms to become extended, moving the load pusher member to an outward position to discharge a load, and whereupon release of the lever causes the operator mechanism to retract the load pusher member to a normal load backing position.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a handtruck incorporating the invention mechanism.

FIG. 2 is a side elevation view of the handtruck of FIG. 1.

FIG. 3 is a side elevation section view taken along line 3-3 of Figure FIG..4 is a side elevation section view illustrating the invention unloading mechanism operated to a partially outward exending or unloading position.

FIG. 5 is a side elvation view illustrating the invention unloader mechanism in a fully outward extending position.

FIG. 6 is an enlarged fragmentary view of an adjustable locking device used in one embodiment of the invention unloader mechanism.

FIG. 7 is a side elevation view illustrating the inven tion handtruck unloader mechanism incorporating the adjustable locking device shown in FIG. 6.

DESCRIPTION OF THE PREFERRED I EMBODIMENT In the following description, the instant invention handtruck unloading mechanism is shown and described in connection with being used on a handtruck adapted for shifting theload center of gravity. Such load shifting handtruck has been more fully shown and described in US. Pat. No. 3,642,301 and is shown only by way of an example of how the invention unloader mechanism may be employed. Those skilled in the art will readily see that the unloader mechanism of the invention generally adapts to any of the well-known forms of handtrucks.

In a preferred embodiment of the invention, the elongated support members comprise telescoping spring loaded tubular segments which in one mode are adapted to telescope freely during an unloading operation. This enables the load backing member to exert even pressure on a load by allowing the load backing member to freely adjust and conform to the abutting surface of the load to be discharged. In another mode the telescoping segments are locked at a fixed length by appropriate apertures and locking pins. In this mode, the load backing member assumes a fixed vertical or angular attitude, providing lift in load discharge.

In the description which follows, the instant invention handtruck unloading mechanism is shown in two embodiments. The first and preferred embodiment comprises an unloading mechanism according to the invention which is secured by telescoping members to a handtruck frame which enables even pressure to be exerted against a load during its discharge. In another embodiment, the unloading mechanism is operated with relatively fixed length securing members to obtain selected unloading characteristics. The invention is shown mounted on a conventional two-wheel handtruck equipped with means for shifting the load center of gravity as previously described in US. Pat. No. 3,642,301.

Referring now to FIG. 1, the invention unloading mechanism is shown mounted on a two-wheel handtruck such as that shown in US. Pat. No. 3,642,301 and comprising a frame having a pair of siderail members l2, 13 each of which include an upward portion defining handles l5, 16. A pair of load supporting forks I9, 20 are suitably secured at right angles on a plate 21 which in turn is welded or otherwise secured to the base of siderail members I2, 13. A bent sheet metal load support plate 17 is rigidly secured to siderail members l2, 13. A rearwardly disposed tilt frame structure is provided by a pair of U-shaped bent

tubular members

22, 23 which are welded or otherwise fixedly secured to

rail members

12, 13. A step bar 24 extends between

members

22, 23 and provides lateral stiffening as well as a step for the operator when tilting the truck rearwardly.

The handtruck frame construction thus far described is typical of those previously used and such a frame readily adapts to receiving either a shifting axle-wheel arrangement such as shown in the drawings or to a nonshifting axle-wheel arrangement. Furthermore, the unloading mechanism of the invention adapts to either type of handtruck. Thus, the following detailed description of the particular axle-wheel arrangement shown in the drawings is described only by way of example.

A pair of

wheels

25,26 mounton an axle 27 which in turn is fixedly secured to a pair of axle support bars 28, 29. Bars 28, 29 are slidably received by fixedly positioned

guide tubes

33, 34. Guide tubes 33, 34- are braced by

horizontal braces

35, 36.

Tubes

33, 34 are also welded or otherwise secured to the respective

tilt frame members

22, 23 to provide additional rigidity. A tension spring 40 is secured at its upper end to a cross .bar 41 extending between the upper ends of axle support bars 28, 29. At its lower end, spring 40 is secured to a fixed bracket 42 (FIG. 3). Since the general operation of such sliding axle-wheel and load center of gravity shifting arrangement is fully explained in the mentioned US. Pat. No. 3,642,30l,no further explanation of how the axle-wheeledarrangement shifts with the load is deemed necessary.

The description next turns to a description of the unloading mechanism to which the invention is primarily directed. At the outset it should again be emphasized that the unloader mechanism readily adapts to a great variety of types of handtrucks and most such handtrucks are of such a construction that the mechanism of the presentinvention can be added without requiring modification of the existing frame or wheel arrangement.

As can be seen from the drawings, FIGS. l-5, an auxiliary U-shaped step bar 50 is pivoted on fixed pivot pins 51 (only one being shown) and operates against the tension of a pair of tension sprins 52 and 53 (FIGS. 3). The lower end of each of the springs 52, 53 is secured to step bar 50 as shown and the respective upper ends are secured as shown to a pair of upper pusher members 54, 55 (FIGS. 1-5) or intermediate pusher members 54' and 55' (FIGS. 67).

On each side of step bar 50 there are pivotally mounted pivotal links 59 and 60 (FIG. 3).

Links

59 and 60 are pivotally linked to and actuate pivotal links 62 and 63 (not shown). Link 62 can be seen to have a pivotal connectiion at its rearward end to a rearward end of a fixed pivotal support bar 65 which is welded or otherwise secured at the opposite end to siderail member 12. A fixed pivotal support 66, like bar 65, while not shown, should be understood as being located in a similar opposite position on the hand truck frame.

Links 62, 63 connect to respective pivotal links 70 and 71 (not shown). Links 70, 71 in turn pivotally connect to lower pusher members 72 and 73 (not shown) on which is mounted a load pusher member 75.

Lower pusher members

72, 73 in turn pivotally connect as shown to

upper pusher members

54, 55 and the latter pivotally connect in turn, as shown, to the respective siderail members l2, 13. While pusher plate 75 is shown as a rigid flat plate, it should be understood that any shape which conforms with the particular load shape may be used. Thus, it could be curved for a curved shape load, e.g., tires.

The operation of the first embodiment shown in FIGS. l-5 will be readily understood with a brief explanation. Once a loaded handtruck reaches its destination, the handtruck, its load and the unloading mechanism of the invention will be generally disposed as in FIG. 2. To unload, the operator will press down manually on the step bar 50 which through the described linkage will cause pusher plate to move outwardly and thereby force the load off the forks I9, 20. 0f particular advantage to unloading bags of seed, fertilizer, and the like, is the fact that the bags are removed without any tendency to tear the bags. Further, the entire load is moved and unloaded together. With an appropriate selection of pivot points, bar lengths, and the like, it will be apparent that such unloading can be accomplished with very little effort on the part of the operator. Note in this connection that the relative step bar leverage distance A is substantially less in FIG. 2 than in FIG. 5 and also that the leverage distances B and C in FIG. 2 are substantially less than the comparable leverage distances in FIG. 5. Also, with the arrangement shown, when a full load of, say, fertilizer bags is being unloaded, pressure on stepbar 50 will tend to tilt the

forks

19, 20 downardly and pusher member 75 will tend to provide a slight lifting force to the load.

In some instances,it is desirable to avoid any lifting force on the load and for this purpose the

upper pusher members

54, 55 are each made as pairs of

mating telescoping members

54, 54" and 55', 55" as best shown in FIGS. 6 and 7. In the embodiment shown in FIGS. 6 and 7, there is employed on both sides of the unloader mechanism an internal spring such as spring in FIG. 6 which extends between pivot pin 81 and a spring support pin 82. There is further employed on both sides of the unloader mechanism a removable pin 83 which can be installed in suitable mating apertures indicated at 84, so as to lock members 54',54" or members 54", 55" together. That is, the

mating telescoping members

54, 54" and 55, 55" can be left in a sliding telescoping relation in order to avoid the load lifting action by pusher plate 75 or these same respective members can be locked together in an appropriate fixed relation to cause plate 75 to give a slight lifting action to the load as it engages and pushes the load off the

forks

19, 20. In this regard, it should of course be understood that the length of the various members and the respective pivotal points in the mechanism forming the subject matter of the invention are selected such as to cause the mentioned selective lifting and non-lifting actions just described. Thus, the load lifting off-vertical angle X (FIG. 4) can be controlled as to magnitude by varying the length of the members and their respective pivots. Further, the amount of forward movement Y (FIG. 5) of pusher plate 75 can also be determined by appropriate selection of the mentioned lengths and pivot locations.

In one embodiment, the distance D(FIG. 5) is approximately 1 foot 336 inches, the length of link 59 is 6-% inches, the length of link 62 is 6% inches, the length of line 70 is 5% inches, the length of support bar 65 is 3 inches and the lengths of

members

54 and 72 are selected accordingly. The two piece connected and pivotal arrangement provided by

members

54 and 72 gives the unique lifting effect previously described whereas the alternate telescoping embodiment shown in FIGS. 6-7 allows such lifting force to be avoided or provided as desired depending on the weight and fragility of the load. Another advantage resides in the fact that the load pusher member 75 operates on the load during discharge very close to the horizontal plane of forks 19, which minimizes interference with normal handling operation, avoids load distortion and tends not to upset the handtruck or load during an unloading or discharge operation. It also needs again to be emphasized that while shown with a sliding axle fitted handtruck by way of example, the independently suspending unloading mechanism of the invention can be seen to be readily adaptable to essentially any conventional tilt type handtruck having a loading frame supported by wheels and on which the invention mechanism can be installed.

What is claimed is:

l. A handtruck for loading and transporting in a normal manner and for forcibly unloading a selected load, comprising in combination:

a. a rigid frame providing a vertically positionable and rearwardly tiltable rectangular front loading plane, rigid load receiving means adjacent the base of and extending generally perpendicularly and outwardly from said loading plane, handle means adjacent the top of and extending rearwardly of said loading plane, and an axle-wheel arrangement supported from said frame rearwardly of the base of said loading plane and being arranged to support the load during its transport and while said loading plane is tilted rearwardly;

b. a load pusher comprisinga first rigid pusher member having a load conforming and load engaging surface; said first pusher member being substantially vertically positionable during loading and unloading operations and during unloading being movable from a first position proximate the loading 2 222.92 $221 9 ps nonv o nardx thsrs isad during such movement being arranged to engage and push the load forwardly on said load receiving means, said push further comprising a pair of elongated support members each comprising a mated pair of telescoping members and each being pivotally connected at a lower end to said first pusher member to provide pivotal support therefrom and at an opposite upper end to said frame and arranged such that said first pusher member is prevented from tending to lift said load during said unloading; and

c. a foot treadle linkage mechanism for actuating said first pusher member including a vertically movable foot treadle arm pivotally mounted on said frame and including linkage members connecting said treadle arm to said first pusher member whereby when said treadle is forced downwardly during unloading said pusher member is forced outwardly to said second position to engage and push said load.

2. A handtruck as claimed in claim 1 wherein each pair of said telescoping member includes means for being releasably locked together.

3. A handtruck as claimed in claim 2 wherein said first pusher member, said second pivotal support members, said treadle arm and said linkage members are arranged by their respective lengths and pivotal connections to cause said'first pusher member to give at least a slight lifting action to the load during unloading when said telescoping members are locked together.

4. A handtruck for loading and transporting in a normal manner and for forcibly unloading a selected load, comprising in combination:

a. a rigid frame providing a vertically positionable and rearwardly tiltable rectangular front loading plane, rigid load receiving means adjacent the base of and extending generally perpendicularly and outwardly from said loading plane, handle means adjacent the top of and extending rearwardly of said loading plane, and an axle-wheel arrangement supported from said frame rearwardly of the base of said loading plane and being arrranged to support the load during its transport and while said loading plane is tilted rearwardly;

. a load pusher comprising a first rigid pusher member having a load conforming and load engaging plate surface, said first pusher member being substantially vertically positionable during loading and unloading operations and during unloading being movable from a first position proximate the loading plane to a second position forwardly thereof and during such movement being arranged to have said plate surface engage and push the load forwardly on said load receiving means, said pusher further comprising a pair of elongated support members each being pivotally connected at a lower end to a point proximate the upper end of said first pusher member to provide pivotal support therefrom and at an opposite upper end to said frame; and c. a foot treadle linkage mechanism for actuating said first pusher member including a vertically movable foot treadle arm pivotally mounted on said frame and including linkage means connecting said treadle arm to said first pusher member, said linkage means including stiff arm linkages between the frame and pusher member whereby when said treadle is forced downwardly during unloading said treadle arm is linked to cause said stiff arm linkage to be extended and said pusher member is forced outwardly to said second position to engage and push said load with the respective end pressure points of the stiff arm linkages on the frame and pusher member being located in a plane parallel to the plane occupied by said load receiving means and proximate the base of said loading plane whereby to avoid tilting of said frame during operation of said treadle arm.

=l t i 1

Claims

1. A handtruck for loading and transporting in a normal manner and for forcibly unloading a selected load, comprising in combination: a. a rigid frame providing a vertically positionable and rearwardly tiltable rectangular front loading plane, rigid load receiving means adjacent the base of and extending generally perpendicularly and outwardly from said loading plane, handle means adjacent the top of and extending rearwardly of said loading plane, and an axle-wheel arrangement supported from said frame rearwardly of the base of said loading plane and being arranged to support the load during its transport and while said loading plane is tilted rearwardly; b. a load pusher comprising a first rigid pusher member having a load conforming and load engaging surface; said first pusher member being substantially vertically positionable during loading and unloading operations and during unloading being movable from a first position proximate the loading plane to a second position f forwardly thereof and during such movement being arranged to engage and push the load forwardly on said lOad receiving means, said push further comprising a pair of elongated support members each comprising a mated pair of telescoping members and each being pivotally connected at a lower end to said first pusher member to provide pivotal support therefrom and at an opposite upper end to said frame and arranged such that said first pusher member is prevented from tending to lift said load during said unloading; and c. a foot treadle linkage mechanism for actuating said first pusher member including a vertically movable foot treadle arm pivotally mounted on said frame and including linkage members connecting said treadle arm to said first pusher member whereby when said treadle is forced downwardly during unloading said pusher member is forced outwardly to said second position to engage and push said load.

3. A handtruck as claimed in claim 2 wherein said first pusher member, said second pivotal support members, said treadle arm and said linkage members are arranged by their respective lengths and pivotal connections to cause said first pusher member to give at least a slight lifting action to the load during unloading when said telescoping members are locked together.

4. A handtruck for loading and transporting in a normal manner and for forcibly unloading a selected load, comprising in combination: a. a rigid frame providing a vertically positionable and rearwardly tiltable rectangular front loading plane, rigid load receiving means adjacent the base of and extending generally perpendicularly and outwardly from said loading plane, handle means adjacent the top of and extending rearwardly of said loading plane, and an axle-wheel arrangement supported from said frame rearwardly of the base of said loading plane and being arrranged to support the load during its transport and while said loading plane is tilted rearwardly; b. a load pusher comprising a first rigid pusher member having a load conforming and load engaging plate surface, said first pusher member being substantially vertically positionable during loading and unloading operations and during unloading being movable from a first position proximate the loading plane to a second position forwardly thereof and during such movement being arranged to have said plate surface engage and push the load forwardly on said load receiving means, said pusher further comprising a pair of elongated support members each being pivotally connected at a lower end to a point proximate the upper end of said first pusher member to provide pivotal support therefrom and at an opposite upper end to said frame; and c. a foot treadle linkage mechanism for actuating said first pusher member including a vertically movable foot treadle arm pivotally mounted on said frame and including linkage means connecting said treadle arm to said first pusher member, said linkage means including stiff arm linkages between the frame and pusher member whereby when said treadle is forced downwardly during unloading said treadle arm is linked to cause said stiff arm linkage to be extended and said pusher member is forced outwardly to said second position to engage and push said load with the respective end pressure points of the stiff arm linkages on the frame and pusher member being located in a plane parallel to the plane occupied by said load receiving means and proximate the base of said loading plane whereby to avoid tilting of said frame during operation of said treadle arm.