Abstract:
A web roll cart for loading, unloading, and transporting rolls of web material wherein a handle may be pivoted between two different orientations, regardless of the presence of a roll of web material thereon. The two handle orientations permit the cart to be steered from either of two sides, and further permits a roll of web material to be presented to a web handling device in either of two orientations. A locking mechanism is provided so that the handle may be locked securely in either orientation while the cart is being steered. In a preferred embodiment, the web roll cart further includes four wheels, with two of the four wheels on casters for steering, and a v-shaped bed for receiving a roll of web material.

Description:
FIELD OF INVENTION 
     This invention relates to the handling of web material for use with web utilization devices. More particularly, this invention relates to a web roll cart for transferring rolls of web material to, from and between such devices. 
     BACKGROUND OF THE INVENTION 
     There are a variety of web handling devices, including impact printers, bursters, collators, inserters and the like. These devices operate on a continuous sheet of web ma- terial fed to and/or from a large roll of web material. While web handling devices work quite well, it is difficult to handle the rolls of web material upon which they operate. A web roll cart is used to transport rolls of web material. A typical prior art roll cart  10  is shown in FIG.  1 . The bed  12  of the web roll cart  10  includes a v-shaped portion  14  formed from a sheet material such as steel for receiving a large roll of web material (not shown). The bed  12  is supported by four wheels including two rear wheels  16  and is two front wheels  18 . The front wheels  18  typically include casters  20  rotatably attached to the bed  12  to permit steering of the web roll cart  10 . The web roll cart  10  also includes a handle  22  with two upright arms  24  and a gripping portion  26  which an operator uses to manipulate the web roll cart  10 . Due to the weight of typical rolls of web material, the arms  24  are reinforced with metal fillets  28  attached between the arms  24  and the bed  12  by welding or other well known securing techniques. 
     Web rolls typically weigh between 400-800 pounds or more. Due to their weight and large size, it is difficult to transport them without damaging the outer layers of web material. Further, due to their circular cross section, the rolls must sometimes be secured in position when unattended or while being transferred between locations. 
     A particular problem arises when transferring rolls between two web handling devices. Web handling devices are typically end-loaded, in the sense that a roll of web material is presented to the device along the axis of web feeding. A wheeled cart with a handle for pushing is typically provided for this task, with an operator wheeling the cart into the web handling device from one end. In this operation, the roll is bounded on all sides, i.e., by the web handling device on the back and top, by the floor on the bottom, by the roll mounting chucks and arms on each side, and by the wheeled cart&#39;s handle on the front. Due to the space constraints created by the web handling device and its chucks, the wheeled cart will have a specific loading end and a handling end which includes an elongated handle so that an operator can direct the roll into position free from interference. This is adequate for a single loading or unloading operation. However, when a roll is transferred between devices, the orientation of the roll must sometimes be changed so that the loading end of the cart presents a roll oriented to feed from the top instead of the bottom, or vice versa. 
     Accordingly, it is an object of the invention to provide a bidirectional web roll cart, i.e., a device which can present a web roll to a web handling device in either of two possible orientations while providing a handle for operator manipulation. The web roll cart should also provide for easy transportation of web rolls, in a manner which prohibits uncontrolled motion of the web rolls. 
     SUMMARY OF THE INVENTION 
     To accomplish the foregoing and other objects, features, and advantages of the invention there is provided a web roll cart for loading and unloading rolls of web material, and for transporting rolls of web material to and from web handling devices that enables a user to easily switch between two handle orientations at selected times regardless of the presence (or absence) of a roll thereon. The invention further provides a locking mechanism such that the handle will be held securely in either orientation while a web roll is being transported. 
     In the preferred embodiment, the web roll cart includes four wheels, with two of the wheels mounted with casters to permit the roll cart to be steered. The web roll cart further includes a pivotally mounted handle which may be swung over the top of the web roll and locked into position on either side of the web roll, thus permitting an operator to s steer the cart from either of two sides, and more particularly permitting an operator to present the web roll to a web handling device in either of two orientations. 
     The web roll cart can also include a v-shaped upper surface for securely receiving a roll of web material having a circular cross section. The web material may be paper or may be other forms of web material generally used in a web handling device, and the web roll may weigh 400-800 pounds or more. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention description below refers to the accompanying drawings, of which: 
     FIG. 1 is perspective view of a prior art web roll cart; 
     FIG. 2 is a perspective view of the web roll cart of the present invention; 
     FIG. 3 is a schematic side view of the pivoting handle of the present invention; 
     FIG. 4 is a perspective view of the locking mechanism of the present invention; 
     FIGS.  5 - 8  are schematic side views showing the unlocking operation of the locking mechanism; and 
     FIGS.  9 - 11  are schematic side views showing the locking operation of the locking mechanism. 
    
    
     DETAILED DESCRIPTION 
     The web roll cart of the present invention can be used with a web handling apparatus adapted to supply web material as might be fed into, for example, a laser printer. One of the substantial improvements relates to the web roll cart&#39;s pivoting and locking handle, which permits bidirectional loading and unloading of web rolls. As further ad- vantages, the present invention provides caster wheels for steering and a v-shaped bed for securely engaging a roll of web material. 
     The web roll cart  30  of the present invention is shown in FIG.  2 . As in the prior art, the web roll cart  30  includes a bed  32  with a v-shaped portion  34  for securely engaging a roll of web material. The web roll cart  30  also includes two wheels on each end  36 ,  38 . One pair of wheels  38  are rotatably attached using casters  40  to permit steering of the web roll cart  30 . Alternatives to casters may be used, such as ball-bearing fixtures, roller- bearing fixtures, or other rotatable mountings, provided they permit the web roll cart  30  to be steered under the weight of a roll of web material. 
     The handle  42  of the present invention has two arms  44 ,  48 , each arm being rotatably mounted to the bed  32  by a pivot  50  near the center of the v-shaped portion  34  of the bed  32 . The pivot  50  may be formed from a metal rod or dowel of appropriate diameter passing through a bed sidewall  51  and the handle  42 . The handle  42  also includes a gripping portion  52  and a hand guard  53  which protects the hands of an operator from being trapped between an object, such as a roll of web material, and the gripping portion  52 . The guard  53  also provides additional structural support to the handle  42 . On each side of the bed  32 , a handle support  54  is mounted. The handle support  54  defines the range of motion in which the pivoting handle  42  may travel. Each arm  44 ,  48  includes a block  55  to support the handle  42  on either of the two handle supports  54 . The block  55  on each arm  44 ,  48  also acts in conjunction with a latch  56  and a gravity lock  58  to securely lock the handle  42  in either of two fully pivoted positions. The locking mechanism  59 , formed by the block  55 , the latch  56 , and the gravity lock  58 , is explained in greater detail below. 
     Referring briefly to FIG. 3, the handle  42  can be seen pivoting over the top of a roll of web material  60  from a first position on the left to a second position on the right. 
     A double arrow  61  indicates the direction of the motion of the handle  42  about the pivot  50 . Through this pivoting motion, the roll of web material  60  may be presented to a web handling device in either of two orientations without removing the roll of web material  60  from the web roll cart  30 . 
     The locking mechanism  59  will now be described with reference to FIG.  4 . The right hand portion of FIG. 4 shows a first gravity lock  58   a . The handle support  54  has two parallel plates, an outer plate  54   a  and an inner plate  54   b . The gravity lock  58   a  is pivotally mounted by a dowel  62  between the two plates  54   a ,  54   b , so that the gravity lock  58   a  can rotate about the dowel  62  as indicated by an arrow  63 . It should be appreciated that a number of pivotal mountings can be employed, including screws, bolts, pins, rivets, or more complex structures such as cylinders mounted on wheel or roller bearing assemblies. Any such mounting may be used, provided it permits the gravity lock to rotate freely in the plane of the two parallel plates  54   a ,  54   b . A second dowel  64  prevents the freely swinging gravity lock  58   a  from falling completely into the space between the two parallel plates  54   a ,  54   b , so that the top portion of the gravity lock  58   a  always remains exposed. The second dowel  64  should be wide enough to engage the parallel plates  54   a ,  54   b  on each side. 
     The left hand portion of FIG. 4, shows the handle  42  in a locked position. The arm  44  of the handle  42  is held in position by the gravity lock  58   b , which is secured between the block  55  of the arm  44  and the latch  56  of the arm  44 . In this position, the handle  42  is prevented from pivoting counterclockwise by the block  55 , which rests upon the top surface  65  of the parallel plates  54   a ,  54   b . The handle  42  is simultaneously prevented from pivoting clockwise by the latch  56 , which has a locking surface  70  abutting an upper matching surface  71  of the gravity lock  58   b . The handle is also prevented from pivoting clockwise by the block  55 , which has a locking surface  72  abutting a lower matching surface  73  of the gravity lock  58   b . The latch  56  is pivotally mounted so that it may rotate away from the gravity lock  58   b , along the arc indicated by an arrow  74 , to unlock the handle, and also so that it may rotate into a position for engaging the other gravity lock  58   a . A leaf spring  75  prevents the latch  56  from disengaging during use or due to external vibration. The leaf spring  75 , and an additional leaf spring (not shown) on the opposing side of the handle also operate to keep the latch  56  centered when the handle  42  is not locked on either side. This dual centering and locking function of the spring can be achieved by any other commonly known spring mechanisms. 
     Refer now to FIGS.  5 - 8 , which show the steps necessary to unlock the handle  42  from its secured position. FIG. 5 shows the handle  42  in its locked position as described above. In FIG. 6, the latch  56  is rotated upward, as shown by an arrow  76 , to permit free motion of the gravity lock  58 . Even with the latch  56  rotated upward, The force of gravity will cause the gravity lock  58  to remain engaged with the block  55 . At this point, the operator must manually rotate the gravity lock  58  up (and counterclockwise) away from the block  55 , as shown by an arrow  78 . Each latch includes two disengaging notches for securing the gravity lock  58  in this intermediate position. One of the notches  80 , in conjunction with the force of a leaf spring  75 , operate to loosely secure the gravity lock in this disengaged position, as shown in FIG.  7 . Once the gravity lock  58  of the first arm  44  (FIG. 2) is so secured, an operator can proceed to disengage and secure the gravity lock  58  of the second arm  48  (FIG. 2) in the same manner. 
     With both of the gravity locks disengaged as shown in FIG. 7, the handle  42  may be freely rotated clockwise into a neutral position along the path indicated by the arrow  80 . FIG. 8 shows the handle in a neutral position. In this position, the gravity locks  58  on the left side will rotate forward (clockwise) such that they are ready to be re-engaged by is the latch  56  and the block  55  on each arm  44 ,  48  of the handle  42 . At the same time, the opposing leaf springs  75  operate to keep the latch  56  centered approximately in line with the handle  42  until the next locking operation. By approximately in line, it is meant that the latch  56  is aligned such that it will initially engage the gravity lock  58  at a correct angle during the locking procedure illustrated in FIGS.  6 - 7 . 
     FIGS.  9 - 11  show how each arm  44 ,  48  of the handle  42  locks into its secured position. Initially, the gravity lock  58  is supported in the proper attitude by a dowel  64 . As shown in FIG. 9, the handle  42  is rotated (clockwise) along the path indicated by the arrow  99  until the block  55  engages the gravity lock  58  on a lower front edge  100 . At the same time, the latch  56  engages the gravity lock  58  on an upper front edge  102 . The continued clockwise motion of the handle  42  initiates two separate motions in the locking mechanism. As shown in FIG. 10, the force of the block  55  on the lower front edge  100  of the gravity lock  58  causes the gravity lock  58  to lift and rotate clockwise along the path indicated by the arrow  103 . At the same time, a corner  104  between the lower front edge  100  and the upper front edge  102  of the gravity lock pushes against the latch  56  causing the latch to rotate against the restraint of the leaf spring  75 , as indicated by the arrow  105 . As shown in FIG. 11, the handle  42  finally travels sufficiently far for the block notch  110  of the gravity lock  58  to receive the block  55 . At this point the gravity lock  58  will rotate forward and engage, in the latch notch  112  on its opposing side, the latch  56 . The block  55  also engages the handle support  54  to prevent further clockwise travel of the handle  42 . 
     Having now described various embodiments of the present invention along with certain variations thereof, it should be apparent to those skilled in the art that other modifications and other embodiments will also fall within the scope of the present invention as defined by the following claims. For example, a number of components of the above-described web roll cart  32  are well known and have many known substitutes. The leaf springs  75  referred to above may instead be a coil spring mounted inside of the latch  56  and attached to the handle  42 . Likewise the dowel  62  may be a screw, a bolt, a hinge, a rod, a pin, or any other mounting device which permits the gravity lock  58  to rotate freely between the two parallel plates  54   a ,  54   b . Accordingly, the above description is meant to be taken by way of example and not to otherwise limit the scope of this invention.