Abstract:
A hand cart useful in transporting one or two cylinders for example of the type used to contain compressed gasses. A preferred embodiment has at least one pair of cylinder-grasping arms rotatable apart to a spread open position for loading and unloading cylinders, and rotatable together to a closed position for holding cylinders. A fold-out prop helps support the cart and tanks so that vertical force is not needed to move the cart forward or backward, and stabilizes the cart while stationary.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to hand trucks and carts, and more specifically to carts for transporting two gas cylinders. 
       BACKGROUND 
       [0002]    U.S. Pat. No. 5,340,136 for “Cylinder Cart with Magnetics” by MacNeil et al. uses magnetic plates to hold two cylinders in place, and uses a foot-pedal actuated cam arrangement to separate the cylinders from the magnets when they are to be removed from the cart. U.S. Pat. No. 6,224,071 for “Three Wheeled Cart for Gas Cylinders” by Dummer uses a chain to hold two cylinders in place. U.S. Pat. No. 5,445,399 for “Retractable Hand Truck having Positive Leg Lock” by Salvucci, Sr. is a three legged cart which relies on gravity to hold one cylinder in place. 
         [0003]    Other patents for two-tank carts include: U.S. Pat. No. D 423,173 for “Double Cylinder Dolly” by Horner et al.; U.S. Pat. No. 5,431,422 for “Tank Truck” by Gamache; U.S. Pat. No. 6,116,623 for “Dual Cylinder Cart with Firewall Divider” by Salvucci; and U.S. Pat. No. 7,273,216 for “Welding Tank Cart System” by Hohrman. 
         [0004]    However, none of the above carts includes both a convenient and effective way to secure gas cylinders or tanks. 
       SUMMARY 
       [0005]    The present invention provides a hand cart which is useful in transporting one or two gas cylinders for example of the type widely used to contain compressed gasses for welding. A preferred embodiment has cylinder-securing means and a fold-out support assembly or prop to help support the cart and tanks so that vertical force is not needed to move the cart forward or backward, and to stabilize the cart while stationary. 
         [0006]    One embodiment features an elongated frame having a bottom end with wheels and a top end with handles; and at least one pair of cylinder-grasping arms pivotally mounted to the frame and rotatable, on axes parallel to axes of the cylinders, apart to a spread open position for loading and unloading cylinders, and together to a closed position for holding cylinders. The embodiment also includes a prop having an upper end pivotally attached to the frame between the bottom end and the top end, and having a lower end which can swing away from the bottom end of the frame and rest on a floor surface to support the cart, and swing toward the bottom end to clear the floor surface so that the cart can be moved on the wheels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a front isometric view of a dual tank cart with grasping arms closed around two cylindrical tanks according to one embodiment of the present invention. 
           [0008]      FIG. 2  is a rear isometric view of the  FIG. 1  cart. 
           [0009]      FIG. 3  is a rear view of the  FIG. 1  cart, without tanks and without a caster support assembly, showing an arm control column with a tiller handle. 
           [0010]      FIG. 4  is a right side view of the  FIG. 1  cart without tanks and with the caster support assembly folded in. 
           [0011]      FIG. 5  is a top view of the  FIG. 1  cart with grasping arms closed around one cylindrical tank. 
           [0012]      FIG. 6  is a front isometric view of the  FIG. 1  cart, without tanks, showing a flip plate floor support in its folded up position. 
           [0013]      FIG. 7  is a detail of the  FIG. 6  cart showing the flip plate floor support in its folded down position. 
           [0014]      FIG. 8  is a detail view of a caster support assembly showing a lock mechanism and foot pedal release. 
           [0015]      FIG. 9  is a detail view of the  FIG. 2  cart showing a parking brake. 
           [0016]      FIG. 10  is a rear view of a first alternate embodiment having an arm control column operated by a vertically sliding foot pedal. 
           [0017]      FIG. 11  is a rear view of a second alternate embodiment having an arm control column operated by a rocking foot pedal. 
           [0018]      FIG. 12  is a rear view of a third alternate embodiment having a pull down handle controlling three grasping arms. 
           [0019]      FIG. 13  is a rear view of a fourth alternate embodiment in which the cylinder securing means includes collar flaps controlled by a vertical ratchet track. 
           [0020]      FIG. 14  is a detail view of the  FIG. 13  embodiment showing collar flaps in place around the necks of two cylinders and showing, in phantom, the collar flaps folded back from the cylinder necks. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    With reference to  FIG. 1 , cart  10  is formed by an elongated frame  12  including vertical members  14  (only one of which is visible) mounted on wheels  16  (only right wheel  16 R is visible) holding two cylinders  18 L,  18 R in upper and lower pairs  20 U,  20 L of cylinder-grasping arms  22 UL,  22 UR,  22 LL,  22 LR in their closed position for transporting the cylinders. The arm pairs  20  are rotatable to a spread open position (not shown) for loading and unloading cylinders  16 .  FIG. 1  also shows part of an articulated support (also referred to as a caster assembly or prop)  30  having wheels  32  (only right wheel  32 R is visible) which swings out to rest on a floor and help stabilize cart  10  while parked or, if desired, while moving. 
         [0022]    In  FIG. 2 , the cart  10  has frame  12  formed by spaced apart parallel elongated vertical members  14 L and  14 R, on the bottom ends of which are wheels  16 L and  16 R. At their top ends vertical members  14 L and  14 R have rearward extending handles  34 L and  34 R, which may be straight as shown in  FIGS. 1 and 2  or curved as shown in  FIGS. 3-6 . Hand levers  36  (only a left lever shown) operate a wheel lock as discussed with reference to  FIG. 9  below. The cylinder-securing means preferably includes vertical slats  38  between the upper and lower cylinder-grasping arms. 
         [0023]    The caster support assembly  30  preferably includes parallel legs  40 L,  40 R having caster wheels  32 L,  32 R restable on a floor, and an upper end, with a cross-bar  42 , pivotally attached by pins  44 L,  44 R (see also  FIG. 4 ) to rotate relative to frame  12  between an open position as shown where the lower end of the support  30  is spaced from the frame  12  so that the cart  10  can be rolled on all four wheels  16 L,  16 R,  32 L,  32 R, or to keep the cart upright while parked, and a closed position ( FIG. 4 ) where the lower end of the support is close to the frame so that the cart can be rolled on the main wheels  16 L,  1 GR. 
         [0024]    In  FIG. 3 , cart  10  (with the tanks and caster support assembly removed for clarity&#39;s sake) has an arm control means embodied as an arm control column  50  and a rotating tiller handle  52 . In this embodiment the left and right vertical members each have a front section ( 14 LF,  14 RF) and a back section ( 14 LB,  14 RB). Left and right back vertical sections  14 LB and  14 RB are preferably connected by a cross-member  54 . The arm control column  50  is preferably positioned between the left and right vertical members  14 L,  14 R and is attached by upper and lower brackets  56 U,  56 L to be rotatable. Control column  50  is attached to upper and lower cams or steering cranks  58 U,  58 L which have right and left attachment points  60 UL,  60 UR,  660 LL,  660 LR connected to respective tie or push rods  62 UL,  62 UR,  62 LL,  62 LR. 
         [0025]    Cylinder-grasping arms  22 UL,  22 UR,  22 LL,  22 LR have pivot joints  64 UL,  64 UR,  64 LL,  64 LR attaching them to adjacent vertical sections  14 LF and  14 RF. Grasping arms  22 UL,  22 UR,  22 LL,  22 LR also have radially spaced attachment points  66 UL,  66 UR,  66 LL,  66 LR where tie rods  62 UL,  62 UR,  62 LL,  62 LR apply lateral force to rotate the arms around the pivot joints between an open position (not shown) for loading cylinders  18  onto the cart  10  and a closed position (as shown) for transporting cylinders in the cart. The steering crank cams  58 U,  58 L are configured to stop just “over center,” to apply maximum grasping force on the cylinders. 
         [0026]    In  FIG. 4 , cart  10  has the caster support prop  30  in its closed position, and a utility box  70  (shown also in  FIG. 6 ) for storing miscellaneous items, mounted on the support prop  30 . From the hinge  44  point of the prop to the bottom of its wheels  32  is less distance than to the bottom of the frame wheels  16 , so the prop wheels  32  do not touch the ground when the prop  30  is closed. 
         [0027]    In  FIG. 5 , cart  10  has grasping arms  22  opened and one cylindrical tank  18 R in the bottom support bracket (detailed in  FIG. 7  below). 
         [0028]    In  FIG. 6 , cart  10  has a bottom support bracket  76  connected to the bottom of the frame  12  and a flip plate  78  in its folded up position. Bottom support bracket  76  is shaped to fit under the edges of cylinders  18  (not shown) so that the cylinders can be lifted without supporting their entire foot surface. The flip plate  78  is held upright until lifted slightly to clear the tabs  74  on each side. Then it can lay flat. 
         [0029]    In  FIG. 7 , cart  10  has the flip plate  78  in its folded down, substantially horizontal, position for supporting cylinders. Flip plate  78  can be used when transporting smaller bottles or odd sized objects. 
         [0030]    In  FIG. 8 , the close-up of a caster support prop  30  shows lock mechanism  80 , and foot pedal lock (release) mechanism  82 . The prop  30  is locked in its open position where the lower end is spaced from the frame  12  to help hold the cart  10  upright. Pressing on foot pedal  82  pulls down the lever of mechanism  80  and releases the lock, allowing the prop  30  to be folded into its closed position. 
         [0031]    In the detail of  FIG. 9 , an optional but preferred hand operated wheel lock  90  (only the left of which is shown, for clarity) is formed by a locking tab  92  which engages and cooperates with notches  94  in a plate  96  on the inside of each wheel  16 . The locking tab  92  is disengaged by pressing hand lever  36  ( FIG. 2 ) downward to raise pull-rod  98 . A spring  99  holds the locking tab  92  in its locked position when the hand lever  36  is released. 
         [0032]    In  FIG. 10 , first alternate embodiment  100  of a dual tank cart has an arm control column  50  similar to the arm control column of  FIG. 3  except, instead of a tiller handle, the column  50  in this embodiment  100  is turned by a vertically sliding foot pedal  102  which slides on vertical guides  104 L,  104 R connected to cross bar  54 . Bell cranks  106 L,  106 R are pivotally attached to respective vertical members  14 L,  14 R between the foot pedal  102  and the arm control column  50 . On the right and left are vertical first rods  108 L,  108 R, connected between the foot pedal  102  and the respective bell crank  106 , and horizontal second rods  110 L,  110 R connected between the bell cranks  106  and a second steering crank  112  on the arm control column  50 . As in embodiment  10 , upper  58 U and lower  58 L steering cranks attached to the control column  50  have right and left attachment points connected by respective tie rods to the attachment points on respective grasping arms. Reciprocal motion of pedal  102  causes reciprocal motion of the arm control column  50 , which in turn causes reciprocal motion of the cylinder-grasping arms  22 . A ratchet lock mechanism (not shown) maintains tension. A release pedal  116  releases the ratchet lock. 
         [0033]    In  FIG. 11 , a second alternate embodiment  120  of a dual tank cart has an arm control column  50  operated by a series of pull rods  108 L,  108 R,  110 L,  110 R and bell-cranks  106 L,  106 R, as in first alternate embodiment  100 , and having a rocking foot pedal  122  which is pivotally attached to an axel  124  between the wheels  16 . 
         [0034]    In  FIG. 12 , a dual tank cart is shown without tanks in a third alternate embodiment  130  having arm control means in the form of a pull down handle  132  which controls three pairs of grasping arms  22 U,  22 M,  22 L. The pull-down handle  132  includes a horizontal transverse section  134  with, at each end, arm portions each including an upper segment  136 L,  136 R, an elbow segment  138 L,  138 R hinged to the adjacent handle member  34 L,  34 R, and a lower segment  140 L,  140 R extending at right angles from the elbow segment. The lower segments  140 L,  140 R are coupled by vertical rods  142 L,  142 R, bell cranks  144 L,  144 R, and horizontal rods  146 L,  146 R to respective middle cylinder-grasping arms  22 ML,  22 MR. Reciprocal motion of the pull-down handle  132  causes reciprocal motion of the cylinder-grasping arms  22 U,  22 M,  22 L. 
         [0035]    In  FIG. 13 , fourth alternate embodiment  150  of a dual tank cart has a cylinder securing means that includes a top holding device or collar flaps  152 L,  152 R which slide down over the tops of, and hold, the cylinders (not shown). The holding device is secured along vertical ratchet tracks  154 L,  154 R which can be released by small release levers  156 L,  156 R. The top holding device  152 L,  152 R optionally has hinges  158 L,  158 R that allow the flaps  152 L,  152 R to move away from the cylinders when not in use.