| 摘要 |
<p>842,440. Selective punching apparatus. INTERNATIONAL COMPUTERS & TABULATORS Ltd. Dec. 18, 1958, No. 40959/58. Class 31 (2). Punching apparatus comprises a plurality of independently lengthwise movable punches arranged for co-operation with a die and normally retained in spaced relation with the die by retaining means individual to the punches and selectively operable to effect release of the punches, the punches on release thereof being movable with and relative to a carrier reciprocable relative to the die and to the punches in their retained positions so that the released punches effect punching due to the kinetic energy thereof and are then restored by the carrier to co-operation with the retaining means. As shown, the punching apparatus comprises punches 15 supported by a carrier 8 reciprocable towards and away from a die 1, the punches being normally retained in spaced relation with the die by energized stationary electromagnets 26 co-operating with armatures 19 fitted at the ends of the punches, and during movement of the carrier towards the die the electromagnets are selectively de-energized to release the punches which are then movable with and relative to the carrier by means of compression springs 20 surrounding the punches, at a speed such that punching is effected by the kinetic energy of the punches. When the carrier moves away from the die it takes with it the selected punches and presents them to the corresponding electromagnets which by this time have again been energized to retain the punches spaced from the die. Each spring is compressible by the carrier during movement thereof towards the die when the punch is in its normally retained position and is so constructed that the load of the spring when compressed by the carrier is less than the magnetic force by which the punch is held in its retained position. The apparatus is similar to that described in copending Specification 842,439.</p> |
