Conveyors: power-driven – Conveyor frame or casing – Adjustable conveyor frame or casing
Reexamination Certificate
2002-12-26
2004-07-13
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor frame or casing
Adjustable conveyor frame or casing
C198S861100
Reexamination Certificate
active
06761265
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The invention generally relates to power driven conveyors. More specifically, the invention relates to a conveyor section of an endless conveyor and to the support, guide, or hold-down means for a carrier belt, especially to a laterally pivotable support for the belt. Another specific aspect of the invention is a conveyor frame that is adjustable, such that the frame flexes or pivots intermediate its ends to move one end relative to the other.
2. Description of Prior Art
In the conveyor industry, the belt conveyor is a basic format. Often such a conveyor provides an endless flat belt carried on a train of rollers. One or more powered rollers drive and support the belt, while idler rollers provide additional support along the length of the conveyor run. This type of conveyor is limited in its uses because the format is not readily adapted to a non-linear path.
An improved type of conveyor belt is capable of following a vertically and horizontally curved path and is available in the United States under the Serpentix trademark, by the Serpentix Conveyor Corporation of Westminster, Colo. This type of belt is characterized by a dished and convoluted, flexible structure. Such a belt can travel around a lateral curve, as well as up, down, or straight, allowing a single belt to carry a load over, under, or around obstacles and through changes in direction. Linear belt conveyors cannot perform these functions with only a single belt. Instead, the load must be transferred to a second linear belt positioned at an angle to the first.
A variety of constructions compliment the improved features of a convoluted belt. U.S. Pat. No. 3,707,218 to Payne et al. shows a conveyor track in which an upper run and a lower run each are defined by two widely spaced, channel-shaped rails. This type of conveyor may be called a multi-rail conveyor. Each rail can be constructed of many small segments so that it can be variably curved. However, each segment must be supported in its location within the overall rail. For this purpose, a transverse joining plate joins each segment of one rail to a similarly positioned segment of each of the other rails; and all of the joining plates are carried on an elongated, resilient, central rod, which gains its external support from legs or other braces. A problem with this structure is that it provides only weak lateral support to the rails and can permit the belt to tip while rounding a curve.
U.S. Pat. No. 4,144,965 to Alldredge et al. shows a similar multi-rail conveyor, but with an improved conveyor track structure in which the joining plates not only are strung on a central rod, but also are strung on resilient rods located near each lateral edge to implement improved lateral stability. The curve is temporarily fixed by mechanically adjusting the effective length of the laterally separated rods. The multi-rail tracks of the Alldredge and Payne patents are heavy duty and difficult to fabricate.
U.S. Pat. No. 4,927,006 to Dolan discloses a conveyor track supporting a single, centerline slide channel suited to carry the same type of dished, convoluted, flexible belt. This type of conveyor may be referred to as a centerline conveyor. The belt is supported at its center over a single, centerline chain that both pulls the belt and supports the load. The chain operates within an elongated centerline track composed of a channel that is closed on three sides and has a pair of side flanges partially closing its fourth side, leaving only a central slot for passage of a joiner between the chain and the belt. If the belt tilts, the tilting is limited when the joiners or chain links become laterally displaced or twisted sufficiently that they contact the channel walls or slot flanges. Thus, the fit between the chain, joiners, and channel determines how much tilting is permitted. The centerline design often uses a plastic liner within the channel, providing a low friction slide surface for contact with the chain. The chain may carry attached plastic sliders for low friction contact with the channel. In addition, the chain may carry lateral extensions to improve its stability against lateral tilting.
A centerline conveyor offers advantages of easier fabrication and typically lower manufacturing cost than a multi-rail conveyor, as described above. It would be desirable to develop a suitable flexible track for a centerline conveyor, but this has proven to be difficult. An elongated centerline channel can be divided into segments, much as done with the rails of a multi-rail conveyor. However, the central positioning of the channel and of its underlying support structure provides little ability to control the arc of the curve. Although the dished, convoluted belt used in these conveyors can bend around a corner, too sharp of a bend will shorten belt life and can produce buckling and sagging.
Extreme measures such as adding widely spaced lateral supports and control rods to a centerline conveyor track might solve the arc control problem, just as achieved in the above Alldredge patent. However, these additions would add significant complexity and cost to the overall design of the conveyor track.
It would be desirable to provide arc control to the track of a centerline conveyor without returning to the multi-rail design.
More specifically, it would be desirable to provide arc control in a flexible centerline conveyor while maintaining the efficient structure for which such centerline conveyors are known.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the invention may comprise the following.
SUMMARY OF INVENTION
Against the described background, it is therefore a general object of the invention to provide an improved conveyor track section that can be flexed laterally while the conveyor remains in operation.
Another object is to provide a flexible track structure suited to carry a conveyor belt through variable lateral curves.
Additional objects, advantages and novel features of the invention shall be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by the practice of the invention. The object and the advantages of the invention may be realized and attained by means of the instrumentalities and in combinations particularly pointed out in the appended claims.
According to the invention, a laterally flexible and longitudinally elongated conveyor track is suited for use with conveyor belt that is capable of lateral bending. A portion of the conveyor track is formed of a plurality of rigid beam segments aligned end-to-end in a series. This track portion is laterally flexible. Each beam segment is formed of an approximately vertical web of predetermined height and a flange that is connected to an upper portion of the web. An elongated plate or strip of flexible and resilient sheet material extends longitudinally along the series of beam segments on at least one side of the aligned webs. A flexible lap plate interconnects at least two juxtaposed beam segments. The lap plate also engages the elongated, flexible sheet by a structure suited for permitting the elongated sheet to move longitudinally with respect to the webs while retaining the elongated sheet. The elongated sheet is permitted to move longitudinally as the conveyor track flexes laterally.
REFERENCES:
patent: 3707218 (1972-12-01), Payne et al.
patent: 4144965 (1979-03-01), Alldredge et al.
patent: 4727981 (1988-03-01), Johansson
patent: 4927006 (1990-05-01), Dolan
patent: 5101734 (1992-04-01), Sakai
patent: 5186314 (1993-02-01), Clopton
patent: 5188035 (1993-02-01), Hideyuki
patent: 6223890 (2001-05-01), Blankemeyer et al.
Dolan Michael S.
Nissen Robert E.
Nusz Robert D.
Bidwell James R.
Rost Kyle W.
Serpentix Conveyor Corp.
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