Abstract:
A hand truck having ground engaging members which tilt the hand truck under conditions of greater leverage than that available by grasping the frame of the hand truck. The ground engaging members are journaled to the frame of the hand truck. In one embodiment, the ground engaging members assume the entire weight of the loaded hand truck. In another embodiment, the ground engaging members push the front end of the hand truck upwardly, employing the wheels as a fulcrum. In the second embodiment, the wheels remain in contact with the ground. In the first embodiment, the ground engaging members serve also as a fulcrum, allowing the wheels to be elevated off the ground. In both embodiments, the ground engaging members are powered either by a foot operated lever or a hand operated lever. In the first embodiment, the foot or hand operated lever is rigidly fixed to the ground engaging members. In the second embodiment, the foot or hand operated lever is a separate part which moves flippers by a multipart linkage. The flippers engage the ground and elevate one end of the load plate.

Description:
RELATED APPLICATION 
     This application is a continuation-in-part of Provisional Patent Application of identical title Ser. No. 60/130,229 deposited with the United States Postal Service on Apr. 20, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to hand trucks, and more particularly to single axle hand trucks having load shifting apparatus. The load shifting apparatus is employed to assist in inclining the hand truck from a vertical stance in preparation for wheeling the hand truck and its load to a new location. 
     2. Description of the Prior Art 
     In operation, hand trucks are usually loaded with bulky and heavy objects when the load bearing frame of the hand truck is substantially vertical. The load is placed on a supporting plate, or load plate. To roll the loaded hand truck to a new location, the hand truck is tilted from its initial vertical stance and drawn by hand. When the hand truck arrives at its destination, where it is unloaded, it is again placed in the vertical stance. It is very difficult for a single person to tilt and upright the hand truck if the load is heavy or particularly bulky. The same holds true when the hand truck is being uprighted after arriving at it destination. 
     Modifications to hand trucks for shifting loads and the center of gravity have been proposed in the prior art. U.S. Pat. No. 3,746,360, issued to Burdette B. Crawford on Jul. 17, 1973, sets forth an arrangement enabling a load bearing frame of a hand truck to be tilted and supported on a member engaging the ground. However, in the hand truck of Crawford, the main load bearing wheels are mounted on side frames which are vertically slidably connected to the load bearing frame and load plate. By contrast, both the wheels and ground engaging members are rotatably fixed to the load bearing frame in the present invention. The load bearing frame is monolithic in that there are no relatively moving parts corresponding to the side frames of Crawford. The device of Crawford includes a hand operated linkage absent in the present invention. The present invention utilizes a foot operated lever pivotally fixed to the load bearing frame to accomplish load shifting, whereas the device of Crawford causes the main wheels to be retracted relative to the load bearing frame and load plate. 
     A hand truck seen in U.S. Pat. No. 2,607,606, issued to Stanley S. Millen on Aug. 19, 1952 has an auxiliary axle disposed below the principal axle and located near the load plate, in the manner of the present invention. However, the auxiliary axle supports rollers which supplement the principal wheels. Unlike the device of Millen, the present invention has solid members which selectively engage the ground to prop the novel hand truck relative to the ground when shifting the load as the hand truck is inclined from the vertical stance. 
     U.S. Pat. No. 2,653,033, issued to Joseph C. Chinette et al. On Sep. 22, 1953, describes a hand truck which is adjustable to vary position of the load plate relative to the principal wheels. However, there is no fixed member which selectively engages the ground when shifting the load as the hand truck is inclined from the vertical, as seen in the present invention. 
     A hand truck seen in U.S. Pat. No. 2,710,106, issued to Alfred H. Hanson on Jun. 7, 1955, includes spurs fixed solidly to the frame which engage the ground when a load is being shifted. However, these spurs are fixed in their positions, and do not project only when moved by a lever, as occurs in the present invention. 
     In U.S. Pat. No. 4,762,333, issued to Carl N. Mortenson on Aug. 9, 1988, the wheels are movable relative to the load bearing frame, whereas the wheels are rotatably mounted in fixed location on the load bearing frame in the present invention. Load shifting is accomplished by Mortenson with the weight of the load and hand truck imposed on the wheels. In the present invention, a ground engaging member pivotally mounted to the load bearing frame projects downwardly to engage the ground responsive to operation of a foot lever, so that the load is partially braced against the ground. 
     U.S. Pat. No. 5,118,124, issued to Craig F. Storay et al. On Jun. 2, 1992, illustrates another hand truck wherein the main wheels are adjustably positioned relative to the load bearing frame. In the device of Storay et al., rockers come to contact the ground and temporarily support the load bearing frame. However, the rockers and wheels are not rotatably or pivotally secured to the load bearing frame in a fixed location, as occurs in the present invention. 
     None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. 
     SUMMARY OF THE INVENTION 
     The present invention sets forth improvements to hand trucks which enable a single person to tilt the hand truck when the hand truck is loaded. Briefly stated, the hand truck is tilted under conditions of relatively great leverage by a retractable tilting or load shifting mechanism. Final tilting is accomplished after retracting the tilting mechanism by grasping the load bearing frame in conventional manner, which affords reduced leverage compared to that available from the tilting mechanism. 
     The load bearing frame comprises a single, rigid assembly devoid of longitudinally movable parts. A novel tilting or load shifting mechanism is fixed to the load bearing frame, and is constrained only to pivot or rotate about its axis of pivot. Thus overall construction of the novel hand truck is uncomplicated compared to the many prior art devices which achieve similar results. Moreover, the present invention may be practiced by modifying a conventional hand truck to include the novel tilting or load shifting mechanism. 
     In some embodiments, the tilting mechanism is foot operated, thereby freeing the hands to grasp the load bearing frame. A foot pedal moves a ground engaging member in a manner shifting the load and the center of gravity. The ground engaging member is arranged to provide a more advantageous lever ratio than is available by grasping the load bearing frame near the top of the upright hand truck. Also, the fulcrum of the leverage arrangement provided by the ground engaging member is more advantageously located relative to the load. Whereas the carriage wheels of the hand truck are usually located well behind the load bearing frame, the fulcrum of the novel leverage arrangement is both closer to the load and lower to the ground than is the axle of the carriage wheels. 
     Foot operation of the novel leverage arrangement enables a user to control the hand truck by grasping the upper end of the load bearing frame while simultaneously shifting the load with one foot. The hand truck gently tilts towards the user, which position is readily controlled by hand. It is then an easy matter to wheel the hand truck to a new location. The foot controls can then be employed to assist in slowly and carefully elevating the loaded hand truck into an erect position, as well as tilting it from the erect position. 
     The leverage arrangement may be hand operated. While the principles are similar, the hand arrangement avoids interference of foot pedals with environmental elements in some situations. In the hand operated embodiment, an elongate lever corresponding to the foot pedal projects upwardly, generally parallel to the back of the hand truck, to a location where it is conveniently grasped by hand. 
     The load shifting mechanism operates in one of either of two ways. In one embodiment, ground engaging members lift the wheels of the hand truck off the ground. In this embodiment, the ground engaging members also serve as a fulcrum. In another embodiment, ground engaging members elevate the front of the hand truck, with the wheels remaining in contact with the ground and serving as a fulcrum. In both embodiments, the ground engaging members selectively project downwardly to engage the ground and to assume at least part of the burden of weight of the loaded hand truck. Each ground engagement style is usable with both hand and foot operators. 
     Accordingly, it is one object of the invention to enable a single person to maneuver and wheel a loaded hand truck. 
     It is another object of the invention to free the hands to grasp the load bearing frame when tilting the hand truck from the erect position. 
     It is a further object of the invention to assist a person in tilting and uprighting a loaded hand truck. 
     Another object of the invention is to return an inclined hand truck to the upright position by using a foot operated actuator, to assist in maintaining balance and control by the user. 
     A further object of the invention is to eliminate back strain and other injuries to users of hand trucks. 
     Still another object of the invention is to provide a tilting mechanism offering a relatively great level of leverage compared to that available by manually grasping and maneuvering the load bearing frame. 
     An additional object of the invention is to form the load bearing frame as a single, rigid assembly devoid of longitudinally movable parts. 
     Still another object of the invention is to employ a conventional hand truck in practicing the invention, the improvement being achieved by securing the novel load shifting mechanism to the conventional hand truck. 
     It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
     FIG. 1 is a perspective view of one embodiment of the invention, with some components removed to reveal detail. 
     FIG. 2 is an environmental side elevational view of the embodiment of FIG. 1, with the hand truck shown in an upright position. 
     FIG. 3 is similar to FIG. 2, but illustrates tilting of the hand truck by the novel load shifting mechanism. 
     FIG. 4 is a perspective view of a second embodiment of the invention, with some components removed to reveal detail. 
     FIGS. 5 and 6 correspond to FIGS. 2 and 3, but illustrate the embodiment of FIG.  4 . 
     FIG. 7 is a perspective view of a third preferred embodiment of the invention wherein the invention has a hand operable lever to actuate ground engaging members, the right wheel of which is removed to reveal detail. 
     FIG. 8 is a side elevational view of the embodiment of FIG. 7, with a user shown operating the hand operable lever. 
     FIG. 9 is a side elevational view of the embodiment of FIG. 7, showing the fully vertical position, with the right wheel removed to reveal detail. 
     FIG. 10 is a side elevational view similar to FIG. 9, showing the tilted position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first embodiment of the invention is shown in FIG.  1 . Hand truck  10  comprises an upright load bearing frame  12  of fixed geometry. As employed herein, “fixed geometry” signifies that the frame is formed as a single part, generally monolithic in construction, with no components which move relative to others. Frame  12  is a box style frame, having right and left vertical channels  14 ,  16  joined by upper cross bar  18  and a lower cross bar not shown in this view. Horizontal braces  22  span vertical channels  14 ,  16 . Frame  12  is typically formed from steel tubing and is typically assembled by welding. Designation of frame  12  as upright signifies that in normal usage, the longitudinal dimension of frame  12  is vertical, or slightly inclined from the vertical. 
     A toe or load plate  24  is welded or otherwise firmly fixed to frame  12  at the bottom and on the front side of frame  12 . Load plate  24  is generally planar. Articles being transported by hand truck  10  are loaded onto load plate  24  and may be propped against frame  12 , if desired. 
     Two carriage wheels  26  are rotatably mounted to frame  12 . Frame  12 , load plate  24 , and wheels  26  are generally conventional, and need not be more explicitly described herein, other than to note that axle  28  and journaled support of the wheels, indicated at  30 , are located on the rear side of frame  12 . Axle  28  establishes an axis of rotation of the wheels. It is further noted that attachment and support of the wheels is fixed in location to frame  12 . By contrast, some prior art hand trucks (not shown) have axle mountings which are adjustably positioned on their respective frames. 
     Hand truck  10  is characterized by a novel load shifting arrangement which when operated moves the center of gravity of hand truck  10 . The load shifting arrangement includes a retractable ground engaging member which is rotatably mounted to frame  12  at a fixed position. That is, the axis of rotation of the ground engaging member is permanently fixed with respect to its location on frame  12 . This location is spaced apart on frame  12  from the location of the carriage wheels. 
     In the embodiment of FIG. 1, the ground engaging member comprises two arms  32 ,  34  fixed to an auxiliary axle  36  which auxiliary axle  36  is journaled in supported relation to frame  12  at bearings  38 ,  40 . Auxiliary axle  36  is a convenient member enabling arms  32 ,  34  to pivot simultaneously and to be supported on a common member. The rotational axis of auxiliary axle  36  and hence of arms  32 ,  34  is preferably parallel to that of axle  28 . Arms  32 ,  34  are of equal length and project from auxiliary axle  36  at similar angles. Arms  32 ,  34  are equidistantly spaced from the center of hand truck  10 , wherein the center demarcates right and left lateral sides of hand truck  10 , arm  32  being located on the left lateral side and arm  34  being located on the right lateral side of hand truck  10 . Weight of hand truck  10  will thus be evenly distributed on arms  32 ,  34 , and no imbalance or lateral tilting will occur. 
     Bearings  38 ,  40  are fixed to frame  12 . A consequence of this arrangement is that wheel axle  28  and auxiliary axle  36 , although rotatable, are both stationary in their mounting location on frame  12 . 
     An operating lever  46  is welded to auxiliary axle  36 . Operating lever  46  is operated by foot, and terminates in a foot pad  48 . Operating lever  46  is a foot lever which extends no more than two feet above the ground, the overall height of hand truck  10  being four feet or more when upright. Operating lever  46  is operated by depressing the same by placing the foot on pad  48  and imposing weight or force on pad  48 . Moving operating lever  46  in this manner causes arms  32 ,  34  to pivot into a first position engaging the ground and lifting hand truck  10  upwardly such that wheels  26  no longer contact the ground. In the first position, arms  32 ,  34  project downwardly when frame  12  is in its usual upright orientation. It is an easy matter to tilt hand truck  10  by grasping the upper portion of frame  12  by hand after the weight of hand truck  10  is transferred onto arms  32 ,  34 . 
     A second position of arms  32 ,  34  is that which exists when arms  32 ,  34  are not being employed to shift the load. In the second position, arms  32 ,  34  project horizontally or otherwise away from the downward direction of the first position. A return spring  50  is anchored to arm  32  at one end and at the other end to any convenient point fixed to frame  12 , such as to axle  28  at a point indicated by  52 . Spring  50  retracts arms  32 ,  34  from the first or deployed position to the second or stowed position. 
     Of course, spring  50  could be anchored to any component solidly fixed to arm  32  in place of being anchored directly to arm  32 . For example, spring  50  could be anchored to arm  34 , lever  46 , or to a projection (not shown) fixed to auxiliary axle  36 . 
     One of the significant advantages of the present invention is that the hands are left free to control and maneuver hand truck  10  without the user being obliged to attempt to place his or her feet as far away from hand truck  10  as possible in order to develop sufficient mechanical advantage over the weight of hand truck  10 , particularly when hand truck  10  is laden. Part of this advantage accrues from location of auxiliary axle  36 , and consequently its axis of rotation, these being between axle  28  and load plate  24 . Another contribution to this advantage springs from leverage ratio established by relative lengths of lever  46  and arms  32 ,  34 , the former being greater than the latter. Effectiveness of the load shifting arrangement can be further enhanced by making the leverage ratio of lever  46  greater than that of the leverage ratio of frame  12 . The leverage ratio of frame  12  is the ratio of the distance from cross bar  18  to the rotational axis of axle  28 , this distance being divided by the distance from axle  28  to toe plate  24 . 
     FIGS. 2 and 3 illustrate operation of hand truck  10 . Hand truck  10  is shown in FIG. 2 to be laden with bags  2 , standing in the upright position on the ground. When a user places his or her foot  4  onto pad  48  and depresses operating lever  46 , hand truck  10  will incline as shown, with its weight being borne by arms  34  and  32  (arm  32  is concealed behind arm  34  in the view of FIG.  3 ). The user then controls and maneuvers hand truck  10  by grasping the upper portion of load bearing frame  12  with one or both hands  6 . 
     FIG. 4 illustrates a second embodiment of the invention. Hand truck  110  of FIG. 4 shares with the embodiment of FIG. 1 a conventional load bearing frame  112 , load plate  124 , and wheels  126  (only one wheel  126  being shown in this view). Hand truck  110  also has a load shifting arrangement having ground engaging members, but the nature of the load shifting arrangement differs from that of the embodiment of FIG.  1 . In the embodiment of FIG. 4, the ground engaging members do not lift the wheels of hand truck  110  out of contact with the ground. Also, operating lever  146  is a member separate from the ground engaging members and the auxiliary axle on which they are mounted. 
     Load bearing frame  112  of hand truck  110  includes right and left vertical channels  114 ,  116  and upper and lower cross bars  118 ,  120 . Horizontal braces  122  span channels  114 ,  116 . A load plate  124  is secured to frame  112 . A carriage wheel  126  supported having axle  128  is journaled, or rotatably supported at a boss or weldment  130 . Weldment  130  is fixed to frame  112  by struts  131 ,  133 . As in FIG. 1, there are two carriage wheels  126  disposed in bilateral symmetry, one wheel being omitted from the view to reveal detail. 
     The load shifting arrangement of hand truck  110  includes two arms  132 ,  134  fixed at their proximal ends to auxiliary axle  136 . Auxiliary axle  136  rotates on bearings  138 ,  140  which are supported on frame  12 . 
     Load plate  124  is located inside arms  132 ,  134 . Arms  132 ,  134  are fixed to auxiliary axle  136  at exposed ends  160 ,  162  of axle  136 . When auxiliary axle  136  is rotated, arms  132 ,  134  will contact the ground at their distal ends and push downwardly on the ground, thereby elevating the front end of hand truck  110 , the front end being that including load plate  124 . 
     Auxiliary axle  136  is rotated by the following arrangement. An operating lever  146  is journaled on or rotatably mounted to frame  12 . In the embodiment of FIG. 4, this is accomplished by mounting lever  146  on axle  128  of hand truck  110 . Operating lever  146  includes a collar  164  which encircles axle  128 . An actuating arm  166  is fixed to collar  164  and projects therefrom so as to contact an actuating projection  168  secured to auxiliary axle  136 . Actuating arm  166  is positioned to contact and drive actuating projection  168  when operating lever  146  is depressed. Actuating arm  166  terminates in a roller  170 . Actuating projection  168  is a curved follower which cooperates with roller  170 . Roller  170  rides across the concave curved surface of actuating projection  168 , thereby moving actuating projection  168  and rotating auxiliary axle  136 . Arms  132 ,  134  pivot accordingly, exerting a force urging load plate  124  upwardly. 
     Operation of the embodiment of FIG. 4 is shown in FIGS. 5 and 6. Referring first to FIG. 5, hand truck  110  is shown laden with bags  2 , standing in an upright posture. When operating lever  146  is depressed by the user&#39;s foot  4 , arms  132 ,  134  rotate and press against the ground, elevating load plate  124 . Hand truck  110  is thereby tilted rearwardly, from which position it is readily controlled and maneuvered by hand. 
     FIGS. 7-10 illustrate a third preferred embodiment of the invention. Hand truck  210  of FIG. 7 includes a conventional load bearing frame  212 , load plate  224 , and wheels  226  (only one of which is shown in this view) which are located on opposite sides of frame  212 . Truck  210  also has a load shifting arrangement having ground engaging members  232 ,  234  which are similar to arms  132 ,  134  of the embodiment of FIG.  4 . 
     Frame  212  of hand truck  210  includes right and left elongate bars  214 ,  216  and upper and lower cross members  222 . The upper ends  215 ,  217  of bars  214 ,  216  respectively form handles  206 ,  208  for use to grasp frame  212  when hand truck  210  is used. Upper and lower cross members  222  span elongate bars  214 ,  216 , and also support central upright support  218  which is fixed at its lower end at the rear edge  204  of load plate  224 . Bars  214 ,  216  are fixed at their lower ends to load plate  224  somewhat inboard from rear edge  204  of load plate  224 . 
     On either side of load plate  224  are located ground engaging members  232 ,  234  which are supported on auxiliary axle  236 . Auxiliary axle  236  is retained to rear edge  204  of load plate  224  by bearings  238 ,  240 ,  242 . Auxiliary axle  236  is axially rotatable within bearings  238 ,  240 ,  242 . Ground engaging levers  232 ,  234  are fixed to auxiliary axle  236  at exposed ends  260 ,  262  thereof such that they will pivot about the axis of auxiliary axle  236  when auxiliary axle  236  is caused to rotate. Each ground engaging member  232 ,  234  is shorter than the rearto-front length of load plate  224 . 
     Wheels  226  are freely rotatable on wheel axle  228 . Wheel axle  228  is provided with elongate spacer  244  mounted therealong. Spacer  244  provides support for block  248  into which may be threaded a stop bolt  258 . Spacer  244  is fixed to brackets  230  (only one of which is shown in FIG. 7) which depend rearwardly from vertical bars  214 ,  216  to support axle  228 . 
     An operating lever  246  extends along the right lateral side of frame  212  and projects beyond the upper end thereof. Lever  246  has an upper end  252  which is curved into an operating handle  254  which is generally parallel to load plate  224 . Operating lever  246  terminates at horizontally oriented handle  254 , which handle  254  extends only part of the width of frame  212 . Operating lever  246  is pivotable about axle  228  by means of collar  264  fixed to lever  246  near its lower end  256 . Mounted to lower end  256  of lever  246  is first linkage member  265  which interconnects lower end  256  with second linkage member  268  which interconnects with third linkage member  268 . The third linkage member  268  connects to auxiliary axle  236 . When operating lever  246  is pulled rearwardly from its handle  254  so as to rotate counterclockwise about axle  228 , second linkage member  266  transmits clockwise motion to third linkage member  268 , causing third linkage member to impart rotation to auxiliary axle  236 . Arms  232 ,  234  pivot responsively about the axis of auxiliary axle  236 , thereby lifting the front of load plate  224  above the ground. This action of arms  232 ,  234  tips frame  212  rearwardly at the upper end of frame  212 , and enables the load borne on load plate  224  to be raised more efficiently and safely by the user of hand truck  210 . 
     Once the load is partially lifted, operating handle  254  may be released, whereupon it will return to a rest position due to urging of spring  250 . This motion reverses motions undertaken by arms  232 ,  234 . 
     The use of elongate operating lever  246  provides ample leverage to the user to begin to tilt the load on load plate  224  backwardly such that less effort is needed to move the load to a position more centrally located over axle  228 . From this position, hand truck  210  is conventionally maneuvered. 
     FIG. 8 illustrates a user  205  grasping a handle  206  in the right hand  209  while drawing handle  254  rearwardly with left hand  207 . The user&#39;s left hand  207  causes operating lever  246  to rotate counterclockwise in the depiction of FIG.  8 . Lever  232  rotates clockwise responsively, engages the ground, and causes frame  212  to rotate in a counterclockwise manner, thereby also rotating load plate  224  such that the load is shifted in the direction of the rear of hand truck  210 . 
     FIGS. 9 and 10 show movement of linkage members  266  and  268 . FIG. 9 illustrates a normal position of hand truck  210 , wherein frame  212  is generally vertical, and load plate  224  is generally horizontal, both relative to the ground. In FIG. 10, lever  246  has been pulled, thereby rotating counterclockwise, in the view of FIG.  10 . Linkage members  266 ,  268  have moved responsively, forcing ground engaging members  232 ,  234  (only member  232  is visible in the side elevation of FIG. 10) to lift load plate  224  into an inclined position wherein the load is shifted. 
     In FIG. 10, it can be seen that a stop is provided to prevent excessive rotation of arm  232 . The stop is in the form of a bolt  258  which engages lower end  256  of operating lever  246 . Bolt  258  is preferably a threaded bolt which is adjustable within threaded block  248  which in turn is fixed to spacer  244 . Excessive rotation of arm  232  about the axis of auxiliary axle  236  would, if not prevented, cause frame  212  to be tilted excessively to the rear, possibly causing an unstable condition which the user could not readily control. Hence bolt  258  is adjusted to stop rotational movement of operating lever  246  about its pivot on axle  228  such that frame  212  is not tilted beyond a stable, controllable position. Of course, bolt  258  could be replaced by any suitable member which interferes with either lever  246  or with any linkage member driving lever  246 . The stop feature need not be adjustable. 
     The present invention is susceptible to further variations and modifications which may be introduced without departing from the inventive concept. For example, indirect actuation of the ground engaging members, as described with reference to the embodiment of FIG. 4, may be applied to the embodiment of FIG.  1 . The number of ground engaging members may be varied. For example, in place of two arms  32 ,  34  or  132 ,  134 , only one arm may be provided. If such is the case, then it would be preferred to locate the one arm such that tilting of the hand truck remains balanced and symmetrical. In further examples, return springs  50 ,  150  (see FIG. 4) may be connected in any suitable way acting to retract the ground engaging members, and need not be anchored only where specifically described herein. 
     Operating lever  46  may be attached directly to an arm  32  or  34 , rather than to auxiliary axle  36 . Similarly, operating lever  146  may be attached to actuating arm  166  rather than to collar  164 , if desired. In still further examples, leverage ratios may be altered to suit. The arrangement of actuating arm and its roller  170  may be replaced by an arrangement wherein the various motion translating members are yoked or otherwise connected, rather than being free to separate as occurs in the embodiment depicted in FIG.  4 . Alternatively, the reversing function wherein direction of rotation is reversed from the actuating arm and the ground engaging members may be accomplished by gears or other mechanical arrangements. 
     The nature of lever  246  is such that it would provide a limited measure of control over load plate  224  if it were fixed solidly to load plate  224 , rather than in the manner including linkage members  265 ,  266 ,  268 . This situation could be achieved in the embodiment depicted in FIGS. 9 and 10, for example, by providing a solid arm (not shown) superseding members  265 ,  266 ,  268 , or by welding members  265 ,  266 ,  268  such that there is no pivot at their connection to each other, to lever  246 , and to auxiliary axle  236 . 
     In a further variation, it would be feasible to modify the embodiment of FIG. 1 such that lever  46  extend along frame  12  in the manner of lever  246  of FIG.  7 . The resultant hand truck would operate in the manner of the embodiment of FIG. 1, but load shifting would be accomplished by one hand. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.