| 摘要 |
A device 1 for engaging and disengaging rollers rollers 14, 15, which are arranged horizontally in pairs, with the shaft ends 18 of the upper rollers being provided with ball bearings 6 which can be lifted and lowered and are guided in bracket-type guides 7. The webs 3, 4 of U-shaped slide members 17 are guided in friction bearings 2, and said slide members can be shifted to and fro by a shifting path X. The webs 3, 4 are provided with recesses 9, 10, each of which possesses a bevelled edge 5a, 5b. The ball bearings 6 roll along the bevelled edges such that in the engaged position the ball bearings are pressed down in the guides 7 by the upper edges 5b, and in the disengaged position they are raised by the lower edges 5a. The recesses 9 provided in the lower web are staggered with respect to the recesses 10 provided in the upper web 4 by the shifting path X. Each slide member 17 is equipped with a gear rack 11 engaged by a gear wheel segment 12, which by use of a swivelling lever 16 can be swivelled about a shaft 13 supported in the side plate 20. The lower rollers 14 are stationarily supported in the side plates 20.
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