Web roll cart

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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'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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] The invention description below refers to the accompanying drawings, of which:

[0011] FIG. 1 is perspective view of a prior art web roll cart;

[0012] FIG. 2 is a perspective view of the web roll cart of the present invention;

[0013] FIG. 3 is a schematic side view of the pivoting handle of the present invention;

[0014] FIG. 4 is a perspective view of the locking mechanism of the present invention;

[0015] FIGS. 5-8 are schematic side views showing the unlocking operation of the locking mechanism; and

[0016] FIGS. 9-11 are schematic side views showing the locking operation of the locking mechanism.

[0017] 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'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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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 58a. The handle support 54 has two parallel plates, an outer plate 54aand an inner plate 54b. The gravity lock 58ais pivotally mounted by a dowel 62 between the two plates 54a, 54b, so that the gravity lock 58acan 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 54a, 54b. A second dowel 64 prevents the freely swinging gravity lock 58afrom falling completely into the space between the two parallel plates 54a, 54b, so that the top portion of the gravity lock 58aalways remains exposed. The second dowel 64 should be wide enough to engage the parallel plates 54a, 54bon each side.

[0023] 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 58b, 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 54a, 54b. 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 58b. 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 58b. The latch 56 is pivotally mounted so that it may rotate away from the gravity lock 58b, 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 58a. 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 54a, 54b. Accordingly, the above description is meant to be taken by way of example and not to otherwise limit the scope of this invention.