Tape reel hub

Abstract: A tape reel hub (14) includes an inner ring (9), an outer ring (5) and angled ribs (6) connecting the two rings (5,9). The ribs (6) deflect upon compression of the outer ring (5) to prevent the transmission of this compression to the inner ring (9).

Description: Technical Field of the Invention The present invention relates to hubs upon which is convolutely wound a tape to produce a tape reel. Background of the Invention As tape is wound upon a hub to produce a tape reel, the tape exerts a uniform compressive force around the circumference of the hub. This compressive force causes the hub to deform inwardly and produces a reduction of the inside diameter of the hub by as much as 0.25 mm. In a production setting, this reduction of the inside diameter of the hub causes the hub to bind on its driving spindle or clutch, thus making the hub difficult to remove and replace. U.S. Patent No. 3,632,053 has addressed this problem by providing resilient beam members between an outer ring and an inner ring, both comprising a hub, which resilient beam members are meant to prevent compression forces on the outer ring from being transmitted to the inner ring and thus reducing its inner diameter. While the teachings of this patent have been effective to somewhat reduce the reduction of the inner diameter of the hub, it has not been totally successful and some reduction of the inner diameter still occurs. FR-A-2233675 discloses a tape reel hub comprising an inner ring, an outer ring having an outer surface and ribs connecting said inner and outer rings, said ribs being angled with respect to a radius of said hub and the outer ring is constrained from compressing. The outer ring is of robust construction and the resiliency provided by the ribs allows relative movement of the inner ring with respect to the outer ring. Summary of the Invention According to the present invention there is provided a tape reel hub having an inner ring, an outer ring having an outer surface defining a tape-winding surface, and ribs connecting said inner and said outer rings and angled with respect to a radius of said hub, characterised in that said outer ring deforms inwardly as the tape is wound thereon; said ribs are weakened adjacent said inner and said outer rings whereby compression of said outer ring by said tape results in angular displacement of said ribs relative to said inner and said outer rings and rotation of said inner ring rather than a compression of said inner ring corresponding to said compressions of said outer ring. The ribs are preferably angled between 45° and 75° with respect to a radius of the hub and, also preferably, include a weakened portion adjacent the inner and outer rings to facilitate angular displacement of the ribs relative to the inner and outer rings. Description of the Drawings The present invention will be more thoroughly described with respect to the accompanying drawings, wherein like numbers refer to like parts in the several views, and wherein: Figure 1 is an elevational view of a tape reel hub according to the present invention; and Figure 2 is an enlarged, elevational view of a portion of the tape reel hub of Figure 1. Description of the Preferred Embodiment A tape reel hub, generally indicated as 4 in Figure 1, includes an outer ring 5, an inner ring 9 and an intermediate ring 7 attached to the inner ring 9 by columns 8. The columns 8 are provided between the intermediate ring 7 and the inner ring 9 to reduce the amount of material necessary to manufacture the tape reel hub 4, but it should be recognized that the entire area between the inner ring 9 and the intermediate ring 7 could be solid. As is shown in both Figure 1 and Figure 2, the intermediate ring 7 is connected to the outer ring 5 by a series of ribs 6. In use, the inner diameter 10 of the tape reel hub 4 is placed over a clutch (not shown) which is driven by a shaft. The tape reel hub 4 is rotated and tape of any sort is wound under tension onto the tape reel hub 4. Because the tape is wound under tension, a compressive force is generated around the entire outer circumference of the outer ring 5. Prior to this invention, the inner ring 9 and the outer ring 5 were rigidly connected so that the com-pressive forces acting on the outer ring 5 were transferred to the inner ring 9 and resulted in a reduction of the inner diameter 10 of the tape reel hub 4. This reduction in diameter of the inner diameter 10 of the tape reel hub 4 caused the tape reel hub 4 to bind on its supporting clutch and made removal of the tape reel hub 4 extremely difficult. By the present invention, this compression of the inner ring 9 and the consequent reduction of the inner diameter 10 of the inner ring 9 is alleviated by the provision of the ribs 6 which connect the inner ring 9 to the outer ring 5. The ribs 6 actually connect the intermediate rings 7 to the outer ring 5, but for purposes of this invention and because the intermediate 7 is rigidly attached to the inner ring 9, it can be considered that the combination of the intermediate ring 7, the columns 8 and the inner ring 9 constitute a single unit which will be collectively referred to in this specification and the attached claims as the "inner ring". The ribs 6 are provided to prevent the compressive forces generated on the outer ring 5 from being transmitted to the inner ring 9 and resulting in a reduction of the inner diameter 10 of the inner ring 9. When the outer ring 5 is subjected to a compressive force which reduces the diameter of the outer ring 5, the ribs 6 are angularly deflected such that the angle between the ribs 6 and a radius of the tape reel hub 4 is increased. This angular deflection of the ribs 6 results in a counter-clockwise rotation, as viewed in Figure 1, of the inner ring 9 rather than a compression of the inner ring 9 corresponding to the compression of the outer ring 5. It will be recognized that compressive forces on the inner ring 9 are not totally eliminated but the action of the ribs 6 reduces the compression of the inner ring 9 to a magnitude which can be tolerated in the production setting for which the tape reel hub 4 is intended. As best seen in Figure 2, the angular displacement of the ribs 6 is facilitated by weakening the ribs at the points 11 where the ribs 6 attach to the rings 5 and 7. The ribs 6 include sufficient material at the mid-point of the ribs 6 to resist buckling or bending of the ribs 6, but include a reduced thickness 11 adjacent the rings 5 and 7 to facilitate the angular displacement of the ribs 6 relative to the rings 5 and 7. The result is ribs 6 which are essentially diamond-shaped in cross-section with a maximum thickness at the mid point of the rib 6 and a narrowed cross-section adjacent the rings 5 and 7. The ribs 6 are preferably angled at 60° with respect to a radius of the tape reel hub 4, as shown. An angle of the ribs 6 with respect to a radius of the tape reel hub 4 of between 45° and 75° has been found to be effective. These limitations are not strict, but at angles of less than 45°, too great a magnitude of the compressive forces exerted on the outer ring 5 are transmitted to the inner ring 9, and 75° with respect to a radius of the tape reel hub 4 is approximately the upper limit because of problems with molding the hub 4 if the angle is increased beyond this value.

Claims: A tape reel hub (4) having an inner ring (9), an outer ring (5) having an outer surface defining a tape-winding surface, and ribs (6) connecting said inner and said outer rings (5, 9) and angled with respect to a radius of said hub (4), characterised in that said outer ring (5) deforms inwardly as the tape is wound thereon; said ribs (6) are weakened (11) adjacent said inner and said outer rings (5, 9) whereby compression of said outer ring (5) by said tape results in angular displacement of said ribs (6) relative to said inner and said outer rings (5, 9) and rotation of said inner ring (9) rather than a compression of said inner ring (9) corresponding to said compression of said outer ring (5). A tape reel hub (4) according to claim 1 wherein said ribs (6) are angled between 45° and 75° with respect to a radius of said hub (4). A tape reel hub (4) according to claim 2 wherein said ribs (6) are angled about 60° with respect to a radius of said hub (4). A tape reel hub (4) according to any preceding claim wherein said ribs (6) are weakened by a decrease in the thickness (11) of said ribs (6) adjacent said inner and said outer rings (5, 7) so that said ribs (6) include sufficient material approximately midway between said inner and said outer rings to resist buckling or bending of said ribs (6) but a reduced thickness (11) adjacent said inner and said outer rings (5, 9) to facilitate said angular displacement of said ribs (6) relative to said inner and said outer rings (5, 9). A tape reel hub (4) according to claim 4 wherein said ribs (6) are each diamond-shaped in cross-section.

Inventors: JORGENSEN CHARLES A C O MINNES, KLINE ROBERT J C O MINNESOTA M, JORGENSEN, CHARLES A. C/O MINNESOTA MINING AND, KLINE, ROBERT J. C/O MINNESOTA MINING AND
Applicants: MINNESOTA MINING & MFG, MINNESOTA MINING AND MANUFACTURING COMPANY
Application year: 1989
Main classification: G11B23
IPC codes: G11B23, B65H75