Improvements in and relating to self-locking core chucks

摘要

951,156. Securing rollers on mandrels. A. T. BLAKE. Nov. 21, 1961, No. 41516/61. Heading F2U. A coupling device designed to lock the core of a roll of web material during winding and unwinding operations to a mandrel comprises a cylindrical chuck body 12 dimensioned to accommodate a core 13. Figs. 1, 2 and 3 show two opposite recesses 14 cut longitudinally into the chuck body 12, with the bottom of each recess terraced in the form of opposite stairs descending towards a common centre groove 5, Fig. 14. Inserted into these recesses are toothed rollers 15 having the same length as the chuck body, which fit closely but freely rotatably, between front and rear retaining rings 9 and 10 respectively. The rollers 15 are provided with neck journals 16, for the purpose of retaining the ends of peripheral springs 17 held within a groove 171 cut into the surface of the chuck body perpendicularly to its axis. The core chuck body 12 is locked to the mandrel shaft 11 by a set screw 25. Each roller has an overall diameter slightly in excess of the greatest depth of the recess 14 with one tooth resting on the bottom of the common centre groove 5 and an opposing tooth adapted to bite into the opposite face of the core 13, Fig. 3, to form a pivot point for a turning of the roller. The roller 15 is forced into ascending the stairs in a direction of the rotary movement of the core 13 or is forced to mount the stairs in the opposite direction of the rotary movement of the mandrel 11, depending whether the rotational movement originates with the core 13 or the mandrel 11. As a result, the uppermost tooth of the roller 15 digs into the core 13 to the extent of ascent upon the stairs and a substantially unbreakable contact between the core 13 and the mandrel 11 is produced. A slight rotational movement of either the core 13 or the mandrel 11 in the opposite direction causes the toothed roller 15 to descend into its rest position within the bottom groove 5. This movement is aided by that one of the two springs 17 which has been under increased tension. In a modification of the above embodiment, the helical springs 17 are replaced by flat leaf springs 18, Fig. 4 (not shown). In a further embodiment, Fig. 7 (not shown), a mandrel that extends the entire length of a core has a helical spring at each end that extends within a diametrical bore to hold the rollers in place. In a further embodiment, Fig. 5 (not shown), its chuck is in the form of a spider wheel with triangular heads at the peripheral ends of each spider arm. The toothed rollers are held in place by short tension springs 20 mounted in borings 201 in each head. In a further embodiment, Fig. 13 (not shown), cylindrical core chucks fit over the ends of a small diameter core. In a further embodiment, Fig. 15 (not shown), which is generally similar to Fig. 3, the peripheral recess 14 has its bottom formed by a platform 2711 urged outwardly by springs 271.