| 摘要 |
1,162,992. Ratchet mechanism. ENGLISH NUMBERING MACHINES Ltd. 14 July, 1967 [20 July, 1966], No. 32698/66. Heading F2Q. [Also in Division G4] A ratchet wheel 2 is driven by a pawl 1, and a toothed wheel 14 is mounted for rotation with the ratchet wheel 2, a retaining member 15 being arranged to extend between adjacent teeth of the wheel 14 during each stepping operation before the stepping movement of the pawl 1 is completed. The retaining member 15 is formed on an arm 6 which is pivotally mounted on a pin 7. The arm 6 carries a pivot pin 5, on which the pawl 1 is mounted, and is pivotally secured to an arm 10 which is urged towards the ratchet wheel 2 by a spring 11 and is movable away from the ratchet wheel 2 by an electromagnet 4 having an armature 40 rigid with arm 10. The arm 6 carries two pins 5, 26 which project through a slot 21 formed in a contact spring 22 having end contact elements 23, 24. A pivoted pawl 16 prevents reverse rotation of ratchet wheel 2. The mechanism is applied to a counting device, toothed wheel 14 meshing a toothed wheel 20 secured to a printing wheel 31 of the counting device. In operation, electric pulses to be counted are fed to terminals 42, 44, Fig. 5, and each pulse causes a stepping movement of pawl 1 under the influence of electromagnet 4 and spring 11, the projection 15 engaging between successive teeth of wheel 14. Resetting of the mechanism to zero may be effected by closing a switch 28 to supply D.C. from terminals 37, 44 to the electromagnet 4. The movements of arm 6 displace contact spring 22 to provide the necessary makes and breaks. |
