| 摘要 |
809,848. Screwing; tapping. SCULLYJONES & CO. Aug. 20, 1956, No. 25430/56. Class 83 (3). [Also in Group XXIV] A safe-torque-clutch for taps and other rotary-tools comprises a cylindrical driving- shell 15 having a degree of resilience, a cylindrical driven-member 18 supported inside the shell 15 by bearings 21, 29 and rollers 33, 34, arranged between the two members. The rollers 33, 34 are retained by a cage 39 acted upon by a drag-ring 52, and co-operate with wedging-surfaces 35-38, Fig. 5, on the member 18. On a drive in one direction or the other the rollers 33, 34 are moved into wedging engagement with either the surfaces 35, 36 or 37, 38, and torque is transmitted to the member 18. On a predetermined safe-torque being exceeded, the rollers over-ride the high-points of the cam surface of member 18 to break the drive by deforming the shell 15. The rollers 33, 34 are held in drive-released positions intermediate the wedging surfaces 35-38 by balls 41, 42 carried in longitudinal-grooves 43, 44 in the cage 39 and co-operating with groove-tracks 45 on the member 18. On reversal of the drive, the rollers 33, 34 are moved into wedging engagement with the other set of surfaces 35, 36 or 37, 38 to transmit torque in the opposite direction. Over-riding on excessive torque takes place in a similar manner in this direction. On resuming the original direction of drive the rollers 33, 34 re-engage with the wedging surfaces 35, 36 or 37, 38 to again transmit torque. The value of the torque transmitted can be varied by the adjustment of a sleeve 46 on a conical outer surface of the shell 15 by means of a screw-thread engagement at one end. |
