Patent GB-512931-A (GB)
Title: Improvements in or relating to prepayment meter mechanism
IPC: G07F15/06
Filed: 1938-02-04
Abstract: 512,931. Prepayment mechanism for meters. GRASEBY, R. C. Feb. 4, 1938, No. 3630. [Class 27] The switch or other commodity control device of a prepayment meter is biassed to the " on " position, retaining means hold it in the '" off " position and an intermediate mechanism then establishes a drive from the prepayment mechanism to the retaining means which becomes inoperative at some stage when driven by the prepayment mechanism, provided the meter is in credit, whereupon the switch &c. is actuated to its " on position. As shown, a switch lever 48, carrying at one end a contact 47 engageable with a fixed contact 46, is biassed to the " on " position by a spring 51, but is held in the " off " position by the engagement of rollers 27 and 24 at its other end with the peripheries of a pair of coaxial rotary discs 11 and 12 except when gaps 26 and 23 in these discs are opposite the rollers. This occurs after the discs have been operated by rotation of the coin barrel 1 provided the credit disc 2 of the meter registers credit. The coin barrel drives the discs against the action of return springs through a coupling 6 and gearing 8, 9, the gear 9 having a driving pin 13 engageable with a pawl 15 on disc 11 which has a driving pin 14 engageable with a pawl 16 on disc 12. Mounted on a pivot 28 on disc 12 is a spring-actuated lever 29 which, during the forward (clockwise) rotation of the disc rocks on its pivot owing to its engagement with a fixed stop 40. As lever 29 rocks, a pin 32 at its shorter end works over a cam 36 on a spring- actuated lever 37 carried by a stationary pivot 38, and ultimately engages catch-fashion behind a step 45 on the lever. A second pin 31 on the short end of lever 29 then depresseslever 37 in the direction to release the pin 32. Before this can occur pawl 16 on disc 12 is rocked by engagement with a fixed pin 21 so that the drive to the disc is interrupted and its spring 19 commences to return it. Meanwhile a pin 42 at the longer end of lever 29 has been approaching the credit disc 2 and reaches a position to engage the disc shortly after the commencement of the return movement of the disc 12 under the action of spring 19. If the disc 2 registers credit, an ungapped part of its periphery is engaged by pin 42 before pin 32 is released from the step 45 in the lever 37 and the return movement of the disc 12 is at once arrested. The disc 11 continues its rotation until its pawl is tripped by engagement with a stop 20 when it is returned to its initial position by its spring. In these two positions of the discs their gaps 23 and 26 are opposite the rollers 24 and 27 so that the supply switch closes. If, however, the credit disc 2 does not register credit, the pin 42 in lever 29 passes into a gap 2a in the credit disc so that pin 31 depresses lever 37 sufficiently to release the pin 32 from the step 45 and disc 12 is con-. sequently returned to its initial position. At no stage are both gaps 23 and 26 in the two discs in register with rollers 24 and 27 so that the switch does not close. When the mechanism is in credit and the switch closed, operation of the coin mechanism has no action on the discs 11 and 12 and the switch since pawl 15 on disc 11 remains tripped by engagement with a stop pin 22 on disc 12 which is in its locked position. When credit is exhausted, the gap 2a in the credit disc releases lever 29 the pin 31 on which rocks lever 37 to release pin 32 so that disc 12 is returned to its initial position in which its gap 23 passes out of register with roller 24 and opens the switch. The coin mechanism 1 and its manner of operation of the credit disc may be as described in Specification 455,620. The credit disc may be returned by a spring under the control of the meter mechanism in the manner described in Specification 294,739, [Class 27].