Patent Publication Number: US-RE37518-E

Title: Lightweight handle

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to handles and more particularly to lightweight handles for lifting and transporting heavy-duty containers. 
     BACKGROUND OF THE INVENTION 
     The use of handles for lifting and transporting various objects is well known. For certain applications, it is desirable to use a handle that is light in weight, yet provides a stable and durable mechanism for lifting heavy objects. This is particularly true in the case of roto-molded plastic containers which are designed for the transport and handling of instruments and electronic equipment in hazardous environments such as those typically found in military, geophysical and news service applications. 
     In the above application, the weight and size of loaded containers necessitate that two or more handles be distributed about the outside of the containers. Said handles are normally required to lie flat against the sides of the containers when not in use. When the container is being carried by the handles, however, the handles are required to stop with their bales perpendicular to the container wall so that the fingers of people lifting the container are not compressed between the handle bales and the walls of the container. Such a handle needs to be capable of lifting heavy-duty containers in the normal upward direction while experiencing heavy side loads and outward pulls. It is also desirable that the handle be capable of quick assembly during commercial production and/or disassembly to replace parts at the customer&#39;s site. 
     A handle developed by the applicants of the present invention is shown in U.S. Pat. No. 5,012,533. Handles of this type, although providing the required strength with less weight than prior conventional handles, are not without their drawbacks. First, the metal bale requires precise bending in two directions and must be heat-treated. For strength and economy, high carbon steel is used which must be plated. Finally, as many as twelve parts must be assembled to make the final handle. Although the performance of such handles is good and achieved at low weight, the cost of manufacture is relatively high. 
     SUMMARY OF THE INVENTION 
     One object of the present invention is to provide a handle assembly which substantially eliminates any relative movement between the handle and the container during transportation. 
     A second object of the present invention is to provide a handle assembly that is easy to assemble and disassemble thereby increasing production efficiency. 
     A third object of the present invention is to provide a strong, light handle that will not corrode nor be weakened by chemical attack. 
     Another object of the present invention is to provide a handle which is more durable and reliable thereby increasing the effective life span of the handle. 
     The above objects are realized by the present invention which is a light weight handle assembly adapted so that a user can stably lift and transport a heavy-duty container. In one embodiment, the handle assembly generally comprises a stationary bracket that mounts to a container wall and a movable handle which is pivotally connected to the bracket. In operation, when the stationary bracket is attached to the container wall, the movable handle may be pivoted between an inoperative position and an operative position. When the stationary bracket is removed or unattached from the container wall, the movable handle may be pivoted to a disengaged position where it may be easily assembled to or unassembled from the stationary bracket. This latter feature provides a handle assembly that is compatible with high production environments and which can be manufactured from a small amount of components. 
     The stationary bracket is also formed with two stationary stop members. Similarly, the movable handle is formed with two movable stop members. The stationary and movable stop members have substantially planar contact surfaces that are adapted so that when the movable handle is pivoted to its operative position, the movable stop members are in substantial stable contact with the stationary stop members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following detailed description will become better understood with reference to the accompanying drawings in which: 
     FIG. 1 is a front view showing the light weight handle assembly of the present invention mounted to a container; 
     FIG. 2 is a top view of the present invention; 
     FIG. 3 is a bottom view of the present invention; 
     FIG. 4 is a rear view of the present invention; 
     FIG. 5 is a side view showing the light weight handle assembly of the present invention in an inoperative position; 
     FIG. 6 is a side view showing the light weight handle assembly of the present invention in an operative position; 
     FIG. 7 is a side view showing the light weight handle assembly of the present invention in a disengaged position; 
     FIG. 8 is a perspective view of the movable handle of the present invention; 
     FIG. 9 is a cross-section view taken along line  9 — 9  of FIG. 4; 
     FIG. 10 is a cross-section view taken along line  10 — 10  of FIG. 4; 
     FIG. 11 is a cross-section view taken along line  11 — 11  of FIG. 4 showing a view of the spring attachment portion of the present invention; and, 
     FIG. 12 is a rear perspective view of the stationary bracket. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, the light weight handle assembly  10  according to the present invention is shown. The handle assembly  10  generally comprises a stationary bracket  12  mounted to a container wall  14  which may be a wall of a roto-molded container or any other container used to carry objects such as sensitive electronic equipment. The handle assembly  10  further comprises a movable handle  16  which is pivotally connected to the stationary bracket  12 . When the stationary bracket  12  is connected to the container wall  14 , the movable handle  16  may be pivoted between an inoperative position (FIG. 5) and an operative position (FIG.  6 ). When the stationary bracket  12  is not attached to or is removed from the container wall  14 , the movable handle  16  may be pivoted to a disengaged position (FIG. 7) wherein the movable handle  16  may be easily assembled to or disassembled from the stationary bracket  12 . This feature of the present invention allows the handle assembly  10  to be quickly assembled, thereby increasing production efficiency. 
     To stabilize the handle assembly  10  while the container is being carried by the handle, the stationary bracket  12  is provided with stationary stop members  18  and  20  while the movable handle  16  is provided with movable stop members  22  and  24 . The movable stop members  22  and  24  and the stationary stop members  18  and  20  are adapted to engage with each other to thereby limit the pivotal movement of the movable handle  16  between its inoperative position (FIG. 5) and its operative position (FIG.  6 ). As will be described more fully herein, both the stationary stop members  18  and  20  and the movable stop members  22  and  24  are provided with substantially planar contact surfaces which increases the effective contact area and reduces the compressive stress in the stop members. 
     Referring to FIGS. 1 and 8, the movable handle  16  comprises a hand gripping portion  26  adapted to be comfortably grasped by a user&#39;s hand. The movable handle  16  further comprises a pair of pivoting arms  28  and  30  that extend from the hand gripping portion  26  and which are generally parallel to each other. As best shown by FIGS. 4 and 8, the movable handle  16  further comprises rotating pivot portions  32  and  34  which extend from the distal end of the pivoting arms  28  and  30 , respectively and which are generally disposed parallel to the hand gripping portion  26 . 
     With reference to FIG. 8, the rotating pivot portions  32  and  34  comprise cylindrical portions  36  and  38 , respectively, which are adapted to freely rotate within a corresponding cylindrical shaped cavity portions  40  and  42  extending inward from a rear surface  44  of the stationary bracket  12 . Cylindrical portions  36  and  38  are captured within the first and second cavity portions  40  and  42  by means of a retainer  48  formed at the upper portion of the cavity portions  40  and  42 . When the movable handle  16  is in its operative position (FIG.  6 ), the cylindrical portions  36  and  38  are in bearing contact with their corresponding cavity portions  40  and  42 . 
     With continued reference to FIG. 8, each of the rotating pivot portions  32  and  34  further comprise a key-way or recess  46  which is adapted such that when the movable handle  16  is pivoted to its disengaged position (FIG.  7 ), the key-ways  46  are in substantial alignment with the retainers  48 . In this disengaged position, the cylindrical portions  36  and  38  of rotating pivot portions  32  and  34  may be easily assembled to or disassembled from cavity portions  40  and  42  of the stationary bracket  12 . 
     Still referring to FIG. 8, each of the rotating pivot portions  32  and  34  further comprise a semi-circular shaped flange portion  50  protruding from respective ends of the cylindrical portions  36  and  38  which are adapted to freely rotate within corresponding cylindrical shaped cavity portions  52  which extend inward from the rear surface  44  of the stationary bracket  12 . When the flange portions  50  are disposed within the cavity portions  52 , the axial movement of the cylindrical portions  36  and  38  and therefore the movable member is limited. 
     The rotating pivot portion  34  further comprises a spring support portion  56  disposed adjacent to and extending from the cylindrical portion  38 . The spring support portion  56  is of generally cylindrical shape and is adapted to receive a torsion spring  58  (FIG.  4 ). The spring support portion  56  is rotatable within a spring attachment cavity portion  60  extending inward from the rear surface  44  of the stationary bracket  12 . The spring support portion  56  comprises a groove  62  that is adapted to secure one end of the torsion spring  58 . The other end of the torsion spring  58  is secured within a channel  64  formed adjacent to the cavity portion  60 . 
     The stationary stop members  18  and  20  are formed on an outside portion  66  of the stationary bracket  12  while the movable stop members  22  and  24  are formed on an outside portion  68  of the pivoting arms  28  and  30 . As best shown by FIGS. 5 and 7, the stationary stop members  18  and  20  are each formed with a substantially planar contact surface  70  which is off-set an angle a to the container wall  14  and/or the rear surface  44  of the stationary bracket  12 . In the preferred embodiment, the angle a is about 45 degrees. Similarly, and as best shown by FIG. 7, the movable stop members  22  and  24  are each formed with a substantially planar contact surface  72  which is off-set an angle b from a top surface  74  of the pivoting arms  28  and  30 . In the preferred embodiment, the angle b is about 45 degrees. In operation, when the movable handle  16  is pivoted from its inoperative position (FIG. 5) to its operative/lifting position (FIG.  6 ), the movable stop members  22  and  24  are brought into substantial contact with the stationary stop members  18  and  20 . As such, the pivotal movement of the movable handle  16  between its inoperative position (FIG. 5) and its operative position (FIG. 6) is about 90 degrees. Furthermore, the planar contour of the contact surfaces reduces the relative movement between the movable handle  16  and the container. The surface area of the contact surfaces  70  and  72  is defined by a length l and a width w. This contact surface area provides for increased stability of the handle assembly  10  when the movable handle  16  is pivoted to its operative/lifting position (FIG. 6) by reducing the shear forces and relative movement between the movable handle  16  and the container. 
     As best shown by FIG. 12, the stationary bracket  12  also comprises a plurality of mounting lugs or bosses  82  disposed on the rear surface  44 . In the preferred embodiment, the mounting lugs or bosses  82  extend from the rear surface  44  and provide shear strength between the bracket  12  and the container wall  14 . In this regard, the hand gripping portion  26  of the movable handle  16  may be upwardly displaced an angle c from a bottom surface  86  of the pivoting arms  28  and  30  to thereby facilitate initial grasping of the hand gripping portion  26 . In the preferred embodiment, the angle c is about 10 degrees. The mounting lugs  82  may further comprise openings  84  adapted to receive a suitable fastener such as a self-tapping screw and the like. Such fasteners are loaded in tension only, and sealing against air passage is accomplished by the employment of rubber-faced washers under the heads of the fasteners. 
     The stress-lowering improvements of the handle of the present invention may best be demonstrated with reference to FIG.  6 . As shown, the handle  16  is placed in its operative/lifting position by an upward force F L  applied to the hand gripping portion  26 . As said handle  16  has two pivoting arms  28 , the upward force on each arm  28  is F L /2. Upward rotation beyond 90° is prevented by a compressive stop force F s  in the contact area between the movable and stationary stop members  22  and  24  and  18  and  20  respectively, and a shear force in the pivot F p . For a specific magnitude of F L , the stop force F s  is inversely proportional to the moment arm J. Thus, to minimize F s , the moment arm J must be as large as possible. This is controlled by the thickness t of the bracket  12  and the diameter of the pivot portions  32  and  34 . When the thickness of the bracket  12  and the handle  16  are approximately the same, the moment arm J will be maximized when the angle of the plane between the axis of the pivot portions  32  and  34  and the stop areas  18 ,  20 ,  22  and  24  is 45° relative to the horizontal. In the preferred embodiment where said angle is 45°, said moment arm J is approximately 1.5 times greater than when contact between the movable stop members and stationary stop members is horizontal. Thus, for the same lifting force F L , the compressive stress in the stop member area of the handle  16  is approximately 33% less. This stress-lowering improvement in the handle  16  makes it possible to produce said handle from polyethylene and the like. 
     As will be clear to those skilled in the art, a change in the ratio of bracket thickness to handle thickness will dictate a change in the angle for maximizing the moment arm J. 
     The stationary bracket  12  and the movable handle  16  may be made from a variety of materials, including but not limited to, polyethylene or any high strength thermoplastic material. To realize additional weight reduction and to reduce material costs and molding time, material from the stationary bracket  12  and the movable handle  16  may removed in various places without significantly reducing the load/strength requirements of the components. By way of example only, the pivoting arms  28  and  30  may be formed with cut-outs  76  (FIG. 5) which eliminate a large amount of material and ribs  78  may be formed to maintain the strength requirements. Similarly, the hand gripping portion  26  may be formed with a hollow inner portion  80  thereby also reducing a significant amount of material. 
     Except for the torsion spring  58  and mounting bolts (not shown), all of features of the handle assembly  10  heretofore described are formed integral to either the stationary bracket  12  or the movable handle  16 . This feature provides a handle assembly  10  that is compatible with high production environments and which is reliable and durable. The stationary bracket  12  and the movable handle  16  may be manufactured by conventional molding processes suitable for use with thermoplastic materials. 
     The foregoing description is intended primarily for purposes of illustration. This invention may be embodied in other forms or carried out in other ways without departing from the spirit or scope of the invention. Modifications and variations still falling within the spirit or the scope of the invention will be readily apparent to those of skill in the art.