Abstract:
A unidirectional conveyor roller for use in a pre-existing conveyor roller system includes a cylindrical roller body supported on a shaft by ball bearing assemblies. A roller clutch bearing between the roller body and the shaft limits relative rotation to a single direction. An internal spring mechanism allows the shaft to be temporarily retracted for facilitating installation on the conveyor roller system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application No. 60/076,421 filed Mar. 2, 1998 by Edwin Arthur Mintonye, II for One Way Roller. 
    
    
     BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to conveyor roller systems and, more particularly, to a conveyor roller designed to permit rotation in only one direction. 
     Various breaking mechanisms for controlling the rotational movement of conveyor rollers are well known to those skilled in the art. In the materials handling industry it is desirable to control the rotational movement of a conveyor roller in order to limit the movement of articles and packages being carried thereon to one direction. 
     For example, U.S. Pat. No. 3,918,561 discloses a brake roller for conveyor systems wherein a tube rotates about a stationary shaft and a speed multiplying transmission within the tube powered by the rotation of the tube operates centrifugally operated friction brake members to prevent an excessive rate of tube rotation. Similarly, U.S. Pat. No. 5,147,020 discloses a conveyor roller brake that is carried within the confines of a conveyor roller. 
     However, such conveyor brake mechanisms are mechanically complex requiring numerous component parts and a high cost of manufacture. Thus, the Unidirectional Conveyor Roller of the present invention has been developed to provide a cost effective mechanism for controlling rotation of the conveyor roller to a single direction. 
     2. Description of Related Prior Art 
     U.S. Pat. No. 3,918,561 to Sven E. Isacsson discloses a brake roller for conveyor systems wherein a tube rotates about a stationary shaft and a speed multiplying transmission within the tube powered by the rotation of the tube operates centrifugally operated friction brake members to prevent an excess rate of tube rotation. Positive drive means are interposed between the tube and the transmission and the friction brake members centrifugally operated are constructed as to make the most efficient use of the centrifugal forces available. 
     U.S. Pat. No. 5,147,020 to Dale Scherman et al. discloses a conveyor roller brake that is preferably carried within confines of a conveyor roller and includes a friction surface carried by the conveyor roller and a brake shoe that is maintained continuously in biased engagement with the friction surface and is selectively engagable or disengagable with respect to a non-rotatable hub element thereby selectively permitting the brake shoe to rotate freely with the conveyor roller in frictional engagement with the friction surface or to be arrested in its rotation so that relative rotation of the roller with respect thereto provides continuous roller braking through frictional sliding of the brake shoe in biased engagement with the friction surface. 
     U.S. Pat. No. 3,899,063 to Orray R. Pollard discloses a roller mechanism associated with roller conveyor systems for controlling buildup of momentum of such systems during use. In this system, a hammer is mounted within one or more substantially cylindrical rollers on the axes thereof. Anvils are positioned on the roller to rotate therewith and to engage the hammer. The hammer is capable of pivotally disengaging the anvils to allow resisted rotational motion of the rollers. 
     U.S. Pat. No. 3,576,242 to Harold H. Mumma discloses a gravity roller conveyor including special braking rollers at spaced intervals which have stationary brake drum attachments adjacent to one of their ends. A pair of brake shoes located within each of the brake drums is pivotally mounted to and rotatable with each braking roller. As the speed of the conveyor rollers increases under a moving load, the centrifugal force acting upon the brake shoes propels them outwardly against the urging of their springs and into engagement with the braking surface of the drum in order to retard speed. 
     U.S. Pat. No. 4,266,659 to Louis H. Meyer et al. discloses an accumulating roller conveyor for conveying articles having a frame and a plurality of conveyor rollers each conveyor roller including a cylindrical drive sleeve supported by longitudinal shaft extending therethrough and rotatably supporting the drive sleeve thereon. This roller conveyor features a one-way clutch mechanism being engagable between each conveyor roller shaft and the associated conveyor roller sleeve to cause the shaft and the sleeve to rotate as a unit to hold out of contact with the drive belt the conveyor rollers in contact with a stopped article as long as the contact article is stopped. 
     U.S. Pat. No. 3,209,880 to Gilbert Dietiker discloses a cargo handling apparatus with an automatic braking mechanism for slowing down and/or stopping runaway cargo. An automatic speed control cargo roller is provided for use in a floor recess. The roller has a belt operated mechanism capable of stopping rotation of the roller when a predetermined speed is achieved. The stopped roller activates a brake shoe member to engage itself with the load thereby preventing the load from further movement. 
     U.S. Pat. No. 3,312,320 to Nicholas J. Froilo discloses a conveyor braking roller including a speed retarding roller for advancing packages and pallets automatically from a loading position to an unloading position without application of propelling power. This device utilizes a complex gearing system and does not limit rotation to only one direction. 
     Finally, U.S. Pat. No. 1,821,618 to Joseph P.Crowley discloses an apparatus for the manufacture of sheet glass which features an overrunning clutch. In the event that the linear speed of a glass sheet exceeds the peripheral speed of the conveyor rollers, the sheet is allowed to drive the rollers faster than they are positively driven along the conveyor. When this occurs, the overrunning clutch is actuated and the glass sheet rides freely over the conveyor rollers. 
     SUMMARY OF THE INVENTION 
     The present unidirectional conveyor roller or One Way Roller, as it has become known in the industry, consists of a cylindrical metal tube having conventional ball bearing assemblies installed at either end thereof. An elongated shaft extends through the pair of ball bearing assemblies and through the hollow tube projecting a short distance at either end thereby permitting rotation of the tube about the shaft in the manner of a conventional conveyor roller. 
     The One Way Roller of the present invention also includes a roller clutch bearing which is installed on the shaft and carried on the interior of the hollow tube to limit rotation to one direction only. 
     In the present One Way Roller the shaft is retractable into the roller body at one end to permit convenient installation into the supporting frame of the conveyor system. 
     In view of the above, it is an object of the present invention to provide a conveyor roller, which permits rotation in only one direction to control the movement of articles being conveyed thereon. 
     Another object of the present invention is to provide a unidirectional conveyor roller which can be conveniently installed in a pre-existing conveyor system to limit the movement of packages conveyed thereon to one direction. 
     Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the unidirectional conveyor roller of the present invention; 
     FIG. 2 is a side elevational view of the unidirectional conveyor roller showing the bearing assembly radially disposed about a hexagonal shaft; and 
     FIG. 3 is a partial sectional view taken through the cylindrical body member showing the arrangement of the internal components thereof. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With further reference to the drawings, there is shown therein a unidirectional conveyor roller in accordance with the present invention, indicated generally at  10  and illustrated in FIG.  1 . The present roller  10  includes a hollow cylindrical body member  12  having counterbored openings formed at either end thereof. 
     In the preferred embodiment the cylindrical body member  12  is constructed of any suitable material such as formed steel tubing or other material having properties suitable for this application. 
     A bearing assembly, indicated generally at  15 , is installed at either counterbored end to an interference fit condition as shown in FIG.  2 . The bearing assemblies  15  are positioned flush with the end of the tubular body member  12  extending approximately ½ inch into the same from either end. 
     Each bearing assembly  15  includes a plurality of ball bearings  16  which are enclosed in a circular race  17  that is disposed within a retaining ring  18  being radially disposed about the bearings  16  in a conventional manner. 
     The inner race  17  is provided with a central opening  19  having a predetermined shape and diameter depending upon the intended application. 
     In the preferred embodiment an elongated, hexagonal shaft  20  extends through the tubular body member  12  and slideably penetrates the opening  19  in either bearing assembly  15  extending a pre-determined distance from either end such that the body member  12  rotates freely about the longitudinal axis of the shaft  20 . 
     The shaft  20  is preferably formed from hexagonal steel stock of a suitable hardness and tensile strength to support the particular application for the conveyor roller  10 . 
     Of course, the cross-sectional shape of the shaft  20  may be varied for a particular application. For example, the shaft  20  may be circular or square in cross-section if desired. In these alternative configurations the openings  19  in the respective bearing assemblies  15  are modified to match the cross-section of a particular shaft. 
     In any case the size of the openings  19  in the bearing assemblies  15  are slightly larger than the outside diameter of the shaft  20  to provide a sliding fit therebetween to permit axial movement of the shaft  15  therein. 
     Referring now to FIG. 3, a compression spring  22  is radially disposed about the shaft  20  at one end thereof adjacent the inner face of a bearing assembly  15 . A shaft pin  24  is inserted through an aperture (not shown) drilled in perpendicular relation to an axis of the shaft to retain the spring  22  in position. 
     A second shaft pin  24  (not shown) is installed through the shaft  20  adjacent the bearing assembly  15  at the opposite end of body member  12  and functions as a stop to permanently capture the shaft  20  within the body member  12 . 
     In this arrangement it will be appreciated that the shaft  20  is capable of being retracted inwardly against the pressure of the spring  22  to facilitate installation of the roller  10  in the conveyor track (not shown). 
     Still referring to FIG. 3 a braking assembly, indicated generally at  25 , is radially disposed about shaft  20  and contained within the tubular member  12  at the end opposite spring  22 . In the preferred embodiment, the braking assembly  25  comprises a roller clutch bearing  30  which permits the body member  12  to rotate in one direction only about the shaft  20  and prevents rotation in the opposite direction. 
     The roller clutch bearing  30  typically includes springs (not shown) integrally molded with the bearing cage  26  to position the roller elements  27  for instantaneous lockup when the body member  12  is rotated relative to the shaft  20  in a predetermined direction. 
     Since such roller clutch and bearing assemblies are well known to those skilled in the art, further detailed discussion of the same is not deemed necessary. 
     Thus, in an assembly procedure of the present conveyor roller, the roller clutch bearing  30  is positioned on the shaft  20  to permit rotation in the desired direction. 
     Next, a bearing assembly  15  is installed in a first end of the tubular member  12  and the shaft  20  together with the braking assembly  25  and the spring  22  is inserted through the tubular body member  12  and into the center opening  19  of the installed bearing. 
     Thereafter, the opposite bearing assembly  15  is installed into the tubular member  12  at an opposite end thereof to permanently capture the shaft  20  therein. 
     Next, the assembled conveyor rollers  10  is installed in the desired position such as on an inclined portion of the conveyor system track to prevent items being conveyed thereon from rolling backwards. 
     From the above it can be seen that the unidirectional conveyor rollers or One Way Roller of the present invention provides a conveyor roller that carries a braking assembly internally of the roller body, which permits rotation in only one direction. 
     The present conveyor roller is rotatably mounted on an elongated retractable shaft for simple installation in the conveyor track. 
     The terms “inner”, “outer”, “side”, and so forth have been used herein merely for convenience to describe the present invention and its parts as oriented in the drawings. It is to be understood, however, that these terms are in no way limiting to the invention since such invention may obviously be disposed in different orientations when in use. 
     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of such invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.