Abstract:
A hand truck with an integral load restraining device comprised of an uptight frame with a handle area, a toe plate which extends forwardly from the bottom of the upright frame and a pair of wheels mounted on the lower rear of the upright frame. Hand truck is equipped with integral universal clamping system arranged for restraining loads of varying geometric configurations back and against the upright frame of the hand truck. The integral clamping system is comprised of a telescoping clamp bar carrying a gear operated load restraining clamp equipped with universal load gripping fingers. Clamp bar and clamp telescope inwardly and outwardly to accommodate cargo of varying depth and are pivotally mounted to a lug inside the vertical slide track, allowing the clamping system to function over the entire height of the hand truck, pivot up and down, swing horizontally from side to side or, be stowed completely out of the way inside the slide track for conventional use of the hand truck

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to hand trucks and more particularly to a two-wheeled hand truck with integral universal clamping system for securing a load to the hand truck.  
           [0002]    Conventional upright two wheeled hand trucks of various designs are well known and have been in use in and around warehouse spaces and cargo docks for many years. They are generally of simple metal construction consisting of an upright frame extending vertically from a load bearing platform or toe plate, a handle area at the top of the upright frame and a set of wheels located near the bottom of the upright frame located on either side of the toe plate. Although hand trucks in their basic simple form are reasonably functional, a universal and common problem involving the use of this type of load transporting device has been the actual loading of cargo onto the hand truck and restraining or securing to the hand truck the many shapes and sizes of loads they are required to accommodate in normal operation. The general procedure for loading a hand truck requires the operator to slide a toe plate located at the base of the upright frame under the load to be moved, then hold the cargo back against the upright frame of the hand truck with one hand while tilting or pivoting the frame back locating the load directly over the wheels into the balanced position necessary for easy transport It is often necessary when a particular load is too great in one or more dimensions to secure the help of another person to provide back pressure necessary for holding the load back in place against the upright frame and on the toe plate of the hand truck while the operator pivots or tilts the load back over the wheels into the balanced position for transport. It is also necessary in most cases for the operator to hold or stabilize the load with one hand to insure that the load remains in place on the hand truck while simultaneously keeping the load balanced over the wheels while pushing and steering the hand truck to it&#39;s destination with the other hand.  
           [0003]    In an effort to better contain loads and simplify the overall handling and operation of hand trucks, a number of solutions to the loading and load restraining problem have been introduced ranging from the addition of specialized clamping or strapping mechanisms to complete and radical reconfiguration of hand truck geometry. The result has been the development of a multitude of different types of specialized hand trucks designed specifically to contain or handle a particular shape or geometric configuration of load such as filing cabinets, gas bottles, barrels and drums, luggage etc. Although these modifications have provided solutions to specific problems, they often times take away from the hand trucks ability to be used as a general-purpose device.  
         PRIOR ART  
         [0004]    An example of a specialized configuration of hand truck would be Turek and Schobergs U.S. Pat. No. 4893824 wherein a hand truck for file cabinets is shown. Although the invention is equipped with a restraining device for containing a file cabinet, it is limited to use on loads that are roughly of the same square or rectangular configuration and size as a file cabinet if the restraining device is to be used. A load or cargo with considerably less depth than that of a file cabinet that is held in place with this retaining arm and clamping mechanism would require the unused or excess length of the retaining arm be extended back through the upright frame area where the operator is standing creating an obstruction for the operator and resulting in difficult manipulation of the hand truck. Additionally, the upright frame consists of an upper frame and a lower frame that are telescopingly mated with the retaining arm extending from the upper frame section. The result of this design characteristic is that the retaining arm will only be functional over the upper half of the hand truck making it difficult to restrain flatter shaped loads or cargo with less height than a single drawer file cabinet.  
           [0005]    Mr. Morissette&#39;s U.S. Pat. No. 4,257,729, Hand Truck, is another example of the more specialized approach; arranged with a system for clamping the bead rim of a barrel or drum thus restraining it to the hand truck. The mechanism outlined in this patent for restraining the load would be of little use for loads that did not have a bead rim or were not a similar cylindrical geometric configuration as a barrel or drum.  
           [0006]    The “Clamping device for use on hand truck” outlined under Mr. Dunnings U.S. Pat. No. 4,492,505 is a load-clamping device added to or mounted on the upright frame sections of a hand truck. This approach is quite satisfactory for a number of load shapes and sizes. It is however somewhat more complicated to use in that the operator is required to select and mount a specific extension bar into an extension housing for restraining a particular type of load. The extension bar required would be dependant upon the type or shape of the load to be secured to the hand truck. It is important to note that the device of this invention secures the load to the hand truck with downward force compressing the load between the clamping mechanism and the toe plate of the hand truck. Although this downward force seems to be suitable for restraining certain geometric shapes of cargo for transport. In most cases it lends little support in the actual loading process as a back force which presses the load back against the upright frame of the hand truck is usually required to keep the load on the toe plate and in place against the upright frame of the hand truck when the upright frame is tilted or pivoted back over the wheels to balance the load for transport. In cases where the load extends outwardly from the upright frame of the hand truck any appreciable distance beyond the support of the toe plate, considerable downward clamping pressure would be required to hold the load securely between the clamp and toe plate to insure that the load remains against the upright frames when the hand truck is tilted back to locate the load over the wheels As mentioned earlier, this particular step in the loading process generally requires that the load receive a backwards pressure holding the load against the upright frame of the hand truck Excessive downward pressure as would be required to keep the load in place would further complicate the loading process if the cargo container is not substantially rigid on all surfaces such as a common square or rectangular cardboard shipping box, or if the load container has insufficient inside reinforcement. In this case it may not be possible to apply the necessary downward pressure required to keep the load back against the upright frame without collapsing the container at the point where the clamping pressure actually contacts the load.  
         SUMMARY  
         [0007]    These are but a few of the examples that demonstrate the need for a hand truck that is truly universal, in that it will accommodate and restrain cylindrical and irregular shaped cargo as well as rectangular shapes over the entire height of the hand truck frame, is easily loaded by one person, has the capability to provide the load holding or restraining forces back against the entire length of the upright frame where it does the most good and can still be used in a conventional manner if clamping or load restraint is not necessary. The present invention offers forth a universal hand truck with an integral clamping system designed to overcome the problems outlined above; comprising an upright frame section formed by two parallel tubular sections joined on the top end to form a handle, a toe plate which joins the upright frame sections at the bottom and extends forward or outward from the base of the upright frame providing for a load bearing surface. A pair of wheels mounted one on either end of the toe plate in such a way as to allow the upright frame to be pivoted or tilted back to locate the load over the wheels or free stand when not in use, supported by the two wheels and the toe plate. A plurality of horizontal metal straps are provided as cross ties extending between the two upright tubular sections adding strength and rigidity to the upright frame of the hand truck. Cross ties are formed in a slight concave arc to provide clearance for a vertical slide track and substantially fixed horizontally between the toe plate and handle of the two upright tubular sections that form the upright frame with approximate equal spacing  
           [0008]    A vertical slide tack for carrying a sliding piston or slide lug and the load-clamping device is fixedly attached to each of the cross ties at a point equal distance between and parallel to the parallel tubular sections that form the upright frame. The vertical slide track is fixedly attached to the top of the toe plate and extends to the uppermost cross tie located a short distance below the frame handle at the top of the hand truck. A front portion of the tubular wall section of the vertical slide track is cut away over the entire length of the vertical slide track to allow for clearance of a coaxial clamping bar and clamping device which pivotally attaches the slide lug to the coaxial clamping bar allowing the load clamping device to be slid from the toe plate to the top of the vertical slide track providing for the ability to clamp or restrain a load over the entire vertical capacity of the upright frame of the hand truck.  
           [0009]    A load clamping device designed to provide for load restraint by applying a clamping force back against the upright frame portion of the hand truck is capable of securing cylindrical, rectangular or irregular shaped loads that fit within an envelope defined by the height of the hand truck and the length of a coaxial bar clamping device. The clamping device consists of a telescoping coaxial clamping bar and a clamp body provided for with load retaining fingers. The coaxial bar which the clamp body is fitted to consists of a plurality of sections, one fitting inside the other and allows for telescopically extending the bar of the clamping device without overhang or obstruction created by an unused portion of a clamping bar when containers or loads that have minimal depth are secured to the hand truck. The clamping body is arranged to slide over the outside tube of the coaxial bar and is equipped with a means for rapidly locating and locking the clamping body to any point along the length of the outside tube of the coaxial bar The clamping body has dual flex mounted clamping fingers located on either side of the clamping body and extending downward and arranged to restrain flat, cylindrical and irregular shaped containers or loads Clamping fingers are engaged providing the necessary back directed force for securing or restraining the load by a simple operator activated handle conveniently located on the top of the clamping body.  
           [0010]    When not in use, the telescoping coaxial clamp bar is collapsed, the clamping body is slid to a stop at the outermost end of the outside tube of the coaxial clamping bar. The clamping device is pivoted to a vertical position on the slide lug and the slide lug and clamping device is slid down into a vertical slide track to a stored position freeing the hand truck for conventional uses that do not require clamping or restraint of the load  
           [0011]    It is the object of this invention to provide a hand truck with an integral load-restraining device. It is also an object of this invention to provide a load-restraining device that can accommodate both cylindrical and rectangular shaped cargo. It is a further objective of this invention to restrain the load by applying a backward force. It is still a further objective to provide a clamping device that collapsible and can be retained inside the hand truck when not in use The foregoing objects including other advantages of the present invention will become obvious to those skilled in the art to which the invention pertains upon review of the following detailed description and drawings in which, 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0012]    [0012]FIG. 1 is a perspective view of the primary components of the hand truck with an exploded view of the clamping components.  
         [0013]    [0013]FIG. 2 is a top view of hand truck  
         [0014]    [0014]FIG. 3 is a perspective detail view of slide lug attachment to inside bar  
         [0015]    [0015]FIG. 4 is a perspective dew view of the coaxial clamp bar lock  
         [0016]    [0016]FIG. 5 is an exploded view of the clamp components  
         [0017]    [0017]FIG. 6 is a side view of clamp handle free sliding position and engagement  
         [0018]    [0018]FIG. 7 is a side view of clamp travel  
         [0019]    [0019]FIG. 8 is a side view showing hand truck load clamping characteristics and clamp stowage when not in use.  
     
    
     DETAILED DESCRIPTION  
       [0020]    Referring now to FIG. 1 which shows an exploded view of the hand truck  10  of the present invention including upright frame  11 , a pair of wheels  12 , a toe plate  13  a vertical slide track  14 , a slide lug  15 , a telescoping coaxial clamping bar  16  comprising an inside bar  17 , an outside bar  18 , a slide lug  15 , and a geared clamp  19 .  
         [0021]    Where in upright frame  11  of hand truck  10  is of a standard height for hand trucks, (approximately 48 inches) and constructed of a tubular metallic material. Upright frame  11  is comprised of a flat metal toe plate  13 , of hand truck  10 . Toe plate  13  is fixedly attached to the bottom of parallel tube sections  20  which extend vertically from toe plate  13  and define the vertical load supporting surface of hand truck  10 . Parallel tube sections  20  are formed at bend  30  and substantially joined at the top of upright frame  11  to form handle  21 , which spans between parallel tube sections  20  and provides a means for the operator to manipulate hand truck  10 . A pair of ground engaging wheels  12  are rotatably fitted to either end of axel  24 . Wheels  12  and axel  24  are mounted to the lower back of parallel tube sections  20  on triangular shaped brackets  26  which extend rearward and are fixedly attached to rear of parallel tube sections  20 . Wheels  12  are mounted at an attitude where wheels  12  point of contact  27  with the ground is on the same horizontal plane as the bottom surface of toe plate  13  when upright frame  11  is setting vertically and unsupported.  
         [0022]    Referring now to FIG. 1 and FIG. 2. A plurality of slightly crescent shaped metal cross ties  22 , evenly spaced one above the other between toe plate  13  and handle  21  span between and are fixedly attached to the back of parallel tube sections  20  and vertical slide track  14  providing for increased rigidity of upright frame  11 . Cross ties  22  are crescent shaped to allow for clearance between vertical slide track  14  and parallel tube sections  20  when loads are placed on hand truck  10  and secured substantially with backward force against parallel tube sections  20 .  
         [0023]    Vertical slide track  14  is constructed of a heavy wall tubular member of approximately 2½ inches in diameter with a portion of the front face cut away  28  providing for clearance and pivotal attachment of inside bar  17  of coaxial clamping mechanism  16  to slide lug  15 . (see FIG. 3). Vertical slide track  14  is fixedly attached at right angles to each of the crossties  22  at points  25  approximately centered and equidistance from parallel tube sections  20 . The base end  29  of vertical slide track  14  is fixedly attached to the top surface of Toe plate  13  and extends vertically and parallel to parallel tube sections  20 . Vertical slide track  14  is of a length approximately equal to the longitudinal dimension of upright frame  11 , as defined by parallel tube sections  20 ,to a point where parallel tube sections  20  begin to form handle  21  at bend  30  of upright frame  11 . Vertical slide track  14  inside diameter is of a dimension which will allow slide lug  15  to fit loosely inside vertical slide track  14  and slide freely within the entire length of vertical slide track  14 . Referring again to FIG. 1 and slide lug  15  detail drawing FIG. 3 where slide lug  15  comprises a metal or composition portion of bar stock approximately 1 ⅞ inches in diameter and 2 ½ inches long slot  31  in slide lug  15  is approximately {fraction (5/16)}″ wide and 1 inch deep and provides for pivotal attachment of inside bar  17  of coaxial clamping bar  16  to slide lug  15  with slide lug pin  32  which passes through slide lug  15  pin hole  33 , through pin hole  34  of inside bar  17  and through slide lug pin hole  33  on the opposite side of slide lug  15 . It is important to note that slide lug pin holes  33  are arranged with a press fit clearance for slide lug pin  32  while pin hole  34  of inside bar  17  is provided for with a loose fit clearance between pin hole  34  and slide lug pin  32  thus allowing coaxial clamping bar  16  to extend substantially up or vertical and axially aligned with vertical slide track  14  to allow for stowage of coaxial clamping bar  16  down and substantially inside vertical slide track  14  when load restraining is not required. It should be noted that vertical slide track  14  and slide lug  15  are cylindrical in cross section allowing for coaxial clamp bar  16  and clamp  19  to be axially rotated inside vertical slide track  14  as necessary to provide additional clearance for clamp  19  when coaxial clamping bar  16  and clamp  19  are in the stowed position inside vertical slide track  14  (see FIG. 8D)  
         [0024]    Referring again to FIG. 1A plurality of lug stop holes  37  are arranged over the length of vertical slide track  14  to provide for stop pin  35  for the purpose of limiting the travel of slide lug  15  and allowing for angular clamping of loads or clamping of loads of irregular configuration when required (see ghost lines in FIG. 8D). Lug stop holes  37  to be drilled through both walls of vertical slide track  14  are sized to provide a slip fit for stop pin  35  which limits the downward travel of slide lug  15  when stop pin  35  is secured substantially through any of the plurality of lug stop holes  37  in vertical slide track  14 . A lanyard  36  of light cord or wire is fixed on one end to a cross tie  22  or some other portion of frame  11  and the other end to stop pin  35  preventing stop pin  35  from being misplaced or lost when not inserted into one of the lug stop  37  holes. Lanyard  36  to be of a length to allow stop pin  35  to be placed into any of the plurality of lug stop holes  37  in vertical slide track  14 .  
         [0025]    Referring again to FIG. 1 where coaxial clamp bar  16  comprises an inside bar  17 , an outside bar  18  with clamp slide stop  38 . Coaxial clamp bar  16  is a telescoping arrangement which allows for varying length of coaxial clamp bar  16  thus enabling clamping of a plurality of load configurations without excessive outward overhang “O” of the coaxial clamp bar  16  from the load (see FIG. 8C) thus contributing to improved and less restricted maneuverability of hand truck  10  when working in confined areas. Inside bar  17  of coaxial clamp bar  16  measures approximately ¼ inch thick by 1 inch wide is approximately 24 inches long and arranged for a sliding fit inside cavity  39  of outside bar  18  with the other end pivotally attached to slide lug  15  as outlined previously. A plurality of detents  40  approximately ¼″ deep and located approximately 3 inches apart over the length and on the upper or top side of inside bar  17  are provided to mate with tang  41  on clamp bar lock  42  located on the end of outside bar  18  (see FIG. 4) for the purpose of locking coaxial clamp bar  16  to a particular operational length as might be desired by the operator. Outside bar  18  of coaxial clamp bar  16  comprises a cast or molded tubular component with a rectangular cross section measuring approximately 1 ½ inches high and 1 inch in width and approximately 26 inches in length. Outside bar  18  to have a rectangular hole through its length, forming cavity  39  with cavity  39  being of a dimension offering proper slip fit clearance for inside bar  17  to be telescopingly received by outside bar  18 . Outside bar  18  is provided for with geared surface  53  arranged in a configuration that will provide for geared tooth  54  (see FIG. 4) profile and pitch to properly mesh with tooth profile of gear  64  on handle  65  of clamp  19  (see FIG. 7) A screw threadedly attached to the slide surface  55  (see FIG. 6) of outside bar  18  on the end opposite face  52  of outside bar  18  serves as slide stop  38  preventing clamp  19  from being slid off the end of outside bar  18 .  
         [0026]    Referring now to FIG. 4 showing clamp bar lock  42  and geared surface  53  of outside bar  18  which extends over entire length of outside bar  18 . Geared surface  53  adjacent to face  52  end of outside bar  18  is provided for with relief  44 , spring seat  49  and ramps  43  to facilitate operational attachment of clamp bar lock  42 . Clamp bar lock  42  to be a pressed, stamped or molded component approximately ¾ inches wide and 2 ¼ inches in length and provides for maintaining length adjustment of coaxial clamp bar  16  as might be required by operator to contain various load configurations on hand truck  10 . Clamp bar lock  42  is pivotally mounted in relief  44  between ramps  43  located on face  52  end of outside bar  18 , and secured with retaining pin  45  which is press fit through pivot holes  50  in ramps  43  of outside bar  18  and provided for with a slip fit through retainer holes  46  on tabs  51  on clamp bar lock  42 . A return spring  47  is provided for applying upward force to bottom side of press tab  48  resulting in a pivotal motion of clamp bar lock  42  around retaining pin  45  resulting in a downward or locking force to lock tang  41  holding lock tang  41  substantially in detent  40  as shown in FIG. 6. Return spring  47  seat  49  is a shallow indentation of about 0.050 inches in depth and is located in relief  44  of outside bar  18  seat  49  retains return spring  47  in relief  44  maintaining proper vertical alignment of return spring  47  between bottom side of press tab  48  and relief seat  49 . In operation, when press tab  48  is depressed, clamp bar lock  42  pivots on retaining pin  45  causing locking tang  41  to be lifted from detent  40  of inside bar  17  allowing inside bar  17  to slide freely within cavity  39  of outside bar  18  to facilitate lengthening or shortening coaxial clamping bar  16  as required by the operator for restraining a particular load configuration with outside bar  18  in the approximate position required, the nearest detent  40  on inside bar  17  is aligned with locking tang  41 , press tab  48  is released allowing locking tang  41  to seat into detent  40  of inside bar  17  locking the length of coaxial clamping bar  16  to the particular desired length  
         [0027]    NOTE. In reference to the following clamp description. As there are a number of gear types and profiles that could be utilized while staying within the confines of this invention actual engineering specifications for gear profile, design and tolerances of the clamp are not outlined as part of this description.  
         [0028]    Referring now to FIG. 5 showing a blowup view of gear clamp  19  whereby clamp  19  comprises a body  56  which is molded of a composition material, cast from metal, or otherwise fabricated. Body  56  to be approximately 6 ¼ inches high from base  57  to top of body ratchets  58 , approximately 1 ⅞ inches from front surface  59  to back surface  60  and 1½ inches in width measured between outside surfaces of cheeks  61 . Each of the two cheeks  61  are provided for with a molded in unidirectional tooth or ratchet profile  58  for mating with ratchet teeth  86  on clamp lock  69 . Ratchets  58  are configured to allow clamp lock  69  of clamp  19  to be moved to the “E” or engaged position (see FIG. 6) or “C”, clamped position (see FIG. 7) and be automatically locked in position by downward pressure of spring  85  of clamp lock  69  Two integral spacers  62  approximately ¼ inch in diameter are molded or otherwise provided between inside surfaces of cheeks  61  for the purpose of adding strength to body  56  and maintaining slip fit containment of outside bar  18  between base  63  of body  56  and gear  64  located on the lower end of handle  65 . Holes  66  are bored substantially through each cheek  61  of clamp body  56  to provide for pivotal attachment of handle  65 . Holes  66  to be approximately ⅜″ diameter. Holes  66  location to be the center point of radius “A”  67 . (See FIG. 6) Radius “A”  67  to be approximately 1 ½ inches also defines the radius of ratchets  58  located on cheeks  61  of body  56 .  
         [0029]    Handle  65  on clamp  19  is provided for applying the force required to move clamp  19  along outside bar  18  back toward parallel tube sections  20  of upright frame  11  and hand truck  10 . Handle  65  of clamp  19  to be a metal or composition material approximately  7  inches long with core  68  cross section to be approximately ½ inch square in shape providing a dimension that will allow for a sliding fit of clamp lock  69  when clamp lock  69  is slid over core  68  for reasons that will be explained later. Gear  64  to have a radius of approximately 1¼ inches measured from the center of hole  71  on handle  65  with a pitch diameter and gear tooth profile arranged mate with geared surface  53  when outside bar  18  is assembled into clamp body  56 . Gear  64  to be manufactured substantially integral to handle  65 . Hole  71  to be approximately ⅜ inches in diameter and bored substantially through core sides  72  of core  68  on vertical centerline  73  of core  68 . Hole  71  provides for pivotal mounting of handle  65  into clamp body  56  when assembled and retained with pin bearing  74 . Bushing collars  76  defmed by a raised portion of material approximately {fraction (1/32)} inches high around the circumference of hole  71  on either side of core  72  serves to decrease friction between core sides  72  of handle  65  and inside surfaces of cheeks  61  when handle  65  is assembled in body  56 . Handle  65  is assembled into body  56  by first orienting heel  77  of gear  64  to face toward the back surface  60  of body  56 . Handle  65  is then slid straight down between inside of cheeks  61  and spacers  62  to a point where hole  71  in handle  65  is directly aligned with cheek holes  66 . Pin bearing  74 , sized to slip fit into holes  66  in cheeks  61  and hole  71  in handle  65  to be inserted through first cheek hole  66 , through hole  70  of handle  65  and on through second cheek hole  66  and seated to a point where head  78  of pin bearing  74  contacts outer surface of cheek  61  on body  56 . Snap ring  80  to be inserted into pin bearing groove  79  securing handle  65  into clamp body  56 .  
         [0030]    Gear  64  on handle  65  is arranged with heel  77  providing a relief for disengagement clearance between teeth on gear  64  and geared surface  53  of outside bar  18  when handle  65  is in the “S” or slide position (see FIG. 6) allowing clamp  19  to be slid freely in either direction on outside bar  18 .  
         [0031]    Clamp lock  69  is comprised of cast metal or molded composition material having a stem  92  that is rectangularly hollow to provide for sliding over handle  65  with the exception of the top end being at a point adjacent to pocket  83  providing for hole  82 . Outside surfaces of stem  92  to be of square cross section measuring approximately ⅞ inches on each side. Stem  92  to be provided for with a with a griping surface  84  on one end for the purpose of lifting clamp lock  69 , compressing spring  85  and disengaging ratchet teeth  86  located on the lower end of clamp lock  69  from ratchets  58  of clamp body  56 . Disengagement of ratchet teeth  86  provides for unrestricted movement of handle  65  in either direction. To assemble clamp lock  69  onto handle  65 . Stem  92  of clamp lock  69  is slid over handle  65  to a point where stud  81  of handle  65  protrudes through hole  82  in pocket  83  of grip  4 . Clamp lock  69  is held in the normal downward locking position by spring  85  which is fitted over stud  81  on handle  65  between pocket  83  and underside of cap  87  during assembly. Cap  87  is fixedly attached to stud  81  on handle  65  with retaining screw  88 . Retaining screw  88  passes through hole  89  in cap  87 , through spring  85  and is threadedly secured in threaded hole  90  to a point where head of retaining screw  88  is seated in countersink  91  of cap  87 . Ratchet teeth  86  are formed into base end of stem  92  of clamp lock  69  and are configured with a tooth geometry and radius that will provide for mated engagement with ratchets  58  on cheeks  61  of clamp body  56 . A light upward or lifting motion by the operator applied to grip  84  on handle  65  disengages clamp lock  69  ratchet teeth  86  from ratchets  58  allowing for free movement of handle  65  back to the “S” position (see FIG. 6) allowing clamp body  56  to move outwardly on outside bar  18  thus relieving pressure of clamp  19  and fingers  94  on the load to enable unclamping of load. Flex pad  93  with load restraining fingers  94  threadedly attached to front surface  59  of clamp body  56  provide for direct contact and containment of load between fingers  94  of clamp  19  and parallel tube sections  20  of hand truck  10 . Fingers  94  are arranged to accommodate both flat surface loads and cylindrical shaped loads by allowing clearance for the radius of cylindrical shaped loads between fingers  94 . Flex pad  93  to be stamped, molded or otherwise constructed of a material with substantial spring like characteristics in an inverted “U” configuration approximately 10 inches wide measured from outside to outside of fingers  94  and approximately 6 inches high measured from top of spring back  95  to tip of fingers  94 . Spring back  95  of flex pad  93  to be of material approximately ⅛ th  inch thick and 1½ inches wide and formed to a concave configuration with approximately ⅞ inches between front surface  96  at the point where mounting holes  97  pass through spring back  95  to front faces  100  of fingers  94 . This distance also defines the amount of flex or “F” of spring back  95  and flex pad  93  as shown in FIG. 6. Fingers  94  of flex pad  93  to extend in a downward direction from top of spring back  95  approximately 6 inches. Fingers  94  to be approximately 1½ inches wide and bent back at point  99  where they converge with ends of spring back  95  to an attitude where front faces  100  of fingers  94  are roughly parallel to front surface  59  of clamp body  56 . Flex pad  93  to be threadedly attached to face  59  of clamp body  56  with four mounting screws  101  which pass through mounting holes  97  in spring back  95  of flex pad  93  and seat into each of four threaded holes  102  located on lower face  59  of clamp body  56 .  
         [0032]    Referring again to FIG. 6  illustrating a side view of clamp  19  and coaxial clamping bar  16  for the purpose of operational explanation wherein press tab  48  on clamp bar lock  42  is depressed allowing operator to slide outside bar  18  either inwardly or outwardly on inside bar  17  to the approximate desired length and allowing locking tang  41  to seat into one of the plurality of detents  40  on inside bar  17  when press tab  48  is released thus locking coaxial clamping bar  16  at the approximate length required as determined by the operator. With handle  65  in the “S” or slide position, as shown with the ghost lines, heel  77  of gear  64  is rotated to a position allowing for clearance between geared surface  53  of outside bar  18  and heel  77  of gear  64  of handle  65  allowing operator to freely slide or position clamp  19  in either direction on outside bar  18  as required to provide for initial contact of fingers  94  of clamp  19  to contact load positioned on hand truck  10 . Upon contact of fingers  94  to the load., clamp handle  65  is rotated forward approximately 45 degrees to the “E” or engaged position where tooth geometry of gear  64  engage the tooth geometry of geared surface  53  of outside bar  18 .  
         [0033]    Referring now to FIG. 7  which shows the actual clamping process wherein tooth geometry of gear  64  on handle  65  of clamp  19  is fully engaged with tooth geometry of geared surface  53  of outside bar  18  resulting in clamp  19  travel “T” as required for secure clamping when handle  65  is advanced approximately 70 degrees and toward the clamped or “C” position. Fingers  94  of clamp  19  will be retained in position by the interlocking of ratchet teeth  86  on clamp lock  69  and ratchets  58  on cheeks  61  of body  56  until operator lifts grip  84  on clamp lock  69  disengaging ratchet teeth  86  from ratchets  58  on cheeks  61  of body  56  thus allowing handle  65  to be moved back to the slide or “S” position, relieving clamping pressure on fingers  94 .  
         [0034]    Referring now to FIG. 8 showing side views of the various types of loads hand truck  10  can accommodate. Wherein FIG. 8-A depicts the maximum size load “A” that can be clamped on hand truck  10  where maximum horizontal length of the load “D” is determined by the distance measured between fingers  94  of clamp  19  and parallel tube sections  20  of upright frame  11  of hand truck  10  and maximum load height “H” will be determined by the measurement between the top surface of toe plate  13  on upright frame  11  and the uppermost point of vertical slide track  14 , where slide lug  15  and Coaxial clamping bar  16  can be positioned.  
         [0035]    [0035]FIG. 8-B shows a flat load configuration “B” wherein clamp  19 , coaxial clamping bar  16  and slide lug  15  have been slid down and positioned near the bottom of vertical slide track  14  for the purpose of clamping and transporting a geometrically flat load with hand truck  10 .  
         [0036]    FIG. 8 -C shows load “C” of a configuration that is relatively high but with little depth. It is important to note that with loads of this geometric configuration, coaxial clamp bar  16  provides for clamp  19  and outside bar  18  to be telescoped or slid substantially over inside bar  17  resulting in a considerable reduction in overhang “O” of the clamping system thus allowing for easier and less restricted maneuvering of hand truck  10 .  
         [0037]    [0037]FIG. 8D shows the ability of coaxial clamp bar  16  and clamp  19  to be utilized at various angles as illustrated by positions “W”, “X”, and “Y” as might be required for clamping irregular shaped loads “I”. Also shown in FIG. 8. D, Stop pin  35  inserted into one of the plurality of lug stop  37  holes which retains slide lug  15  at a selected height in vertical slide track  14  as may be required by operator to aid in clamping various irregular shaped loads on hand truck  10  Ghost lines show coaxial clamp bar  16  in position “Z” angled vertically on slide lug  15  and in position to stow the clamping system by sliding coaxial clamp bar  16 , and slide lug  15  down the inside of vertical slide track  14  providing for conventional use of hand truck  10  which may not require clamping of the load It can be seen that the forgoing description of the preferred embodiment satisfies the objectives of the invention in that the load-restraining device for the hand truck is an integral part of the hand truck frame however can be completely stowed within the frame allowing for conventional use of the hand truck when required. The restraining unit also is capable of clamping a wide variety of load configurations including cylindrical shapes by applying a backward force against the upright frame and has clamping capability over the entire height of the hand truck frame. The preferred embodiment as described herein has been presented for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations to the hand truck frame as well as the clamping system as outlined herein are possible in light of the above teaching. It is intended that the scope of the invention not be limited by this detailed description but rather by the claims appended hereto.