Patent GB-660635-A (GB)
Title: Improvements relating to taximeters
IPC: G07B13/00
Filed: 1949-12-09
Abstract: 660,635. Fares registering, taximeters. BELL PUNCH CO., Ltd., and WEBB, C. F. Dec. 9, 1949, No. 31735/49. Class 106 (iii). The vehicle drive in a taximeter comprises an eccentric which is arranged to rotate a predetermined basic number of revolutions per mile of vehicle travel, and is provided with an adjustable degree of eccentricity to vary the distance of travel allocated to a unit of fare registration of the meter, i.e. the tariff may be adjusted by alteration of the throw of the crank-pin which in co-operation with an oscillating member drives the fare-registering mechanism. Figs. 1, 2 and 3 are respectively three elevational views of the meter from one side thereof showing the parts of the vehicle drive in three possible settings, namely " Zero registration " (Fig. 1), " Normal tariff " (Fig. 2), and " Maximum tariff " (Fig. 3). The shaft 22 is driven from the transmission of the vehicle via a conversion unit so that the revolutions per mile are a basic number, e.g. 30, the taximeter being conditioned to the vehicle and road wheel size by interchange of gears in the conversion unit. From the shaft 22 the drive is through a crank of adjustable radius comprising a wheel 28 coaxial and fast on shaft 22 having upon the face a pin disc 29 secured by a clamping screw 30, the distance of the pin 31 of the disc being adjustable by adjustment of the pin disc to vary the tariff rate of the meter. The pin 31 works in a slot 32 in one arm 33 of a bell-crank 34 oscillating in a vertical plane about a fixed axis 35. The bell-crank 34 is mounted on a pivot 36 (Fig. 5). A second bell-crank 38 is mounted on a pivot 37. One arm is pivotally connected at the free end by a pivot 40 to the upper end of a downwardly extending link 41, on which is a pivot 42 mounting a pair of simultaneously reciprocating rack pawls 43, 44, urged by a tension-spring 45 into engagement with a ratchet-wheel 46 coaxial and fast with a shaft 7 carrying the fare registering mechanism 4, 5, 6. The pivot 42 extends through a curved slot 47 in the other arm 48 of the bell-crank 34 and its position along this slot is determined by the angular setting of the bell-crank 38. Thus, in Fig. 1 the pivot is at the upper end of the slot in alignment with pivot 36 so that oscillations of the bell-crank 34 produce no movement of the pivot 42 and therefore no movement of the fare registering mechanism. In Fig. 2 it is midway along the slot so that the pawls 43, 44 oscillate as shown by the interrupted line in the drawing to produce rotation of the ratchet-wheel 46 and shaft 7. In Fig. 3 the pivot 42 is at the bottom of the slot, increasing the throw of the pawls and imparting approximately twice the movement to the ratchet-wheel at each stroke. The angular setting of the bell-crank 38 is determined by the angular setting of a cam 49 carried on a cam-shaft 50 to which is fastened the " flag 51 of the meter. Thus, in Fig. 1, which shows the flag in the " For hire " position a cam follower roller 52 is engaged on a high part 53 of the track of the cam. In Fig. 2, which shows the flag in the " Normal tariff " position the roller is on an intermediate part of the track. In Fig. 3, which shows the flag in the " maximum tariff" position the roller is engaging a low part 55 of the track. The taximeter described combines in one instrument all four of the principal features respectively forming the subject-matter of the present invention and Specifications 660,636, 660,637 and 661,347. Summarized, these features are: (a) Use as the primary agent for registration of distance of a crank rotatable through a predetermined basic number of revolutions per mile of vehicle travel, and of adjustable throw to vary the tariff obtained. (b) Use of a pawl and ratchet system under the control of the meter flag giving more than one tariff by adjustment of the flag. (c) A pawl and ratchet mechanism giving substantially uniform rotation to the ratchet wheel and fare registering mechanism. (d) A clock drive with means for adjusting the time interval allocated to a unit of registration of the meter.