Patent GB-546688-A (GB)
Title: An improved maximum average rate indicator
IPC: G01R11/60
Filed: 1940-11-15
Abstract: 546,688. Speedometers. ENGLISH ELECTRIC CO., Ltd., TILSTONE, G., and CLEMENCE, E. Nov. 15, 1940, Nos. 16526/40 and 11350/41. [Class 106 (iii)] [Also in Group XXXVI] Maximum average rate of consumption, flow, travel, &c is registered by measuring the total consumption &c. in each of a plurality of overlapping equal time intervals and registering that total which is a maximum. As shown in Fig. 1, five ratchet wheels 1 ... 5 are freely mounted on a common spindle and each is provided with a spring 6 tending to return it to its initial position. Pawls 7 ... 11 are reciprocated together by means of an electromagnet 13 energized through contacts actuated by the meter and advance all the ratchet-wheels 1 ... 5 together. These are held by detents 14 ... 18 which are lifted in turn by cams 23 ... 27 on a cam-shaft 19 which is driven through ratchet gear 20, 21 by an electromagnet 22 energized from a standard clock, the cam-shaft making one revolution in thirty minutes. The cams 23 ... 27 are angularly spaced 72 degrees apart so that the ratchet-wheels are unlocked in sequence, one being freed every six minutes. Each of the wheels 1 ... 5 carries a peg which engages and drives forward a bar 28 which is frictionally held in its maximum position and drives forward a pointer 29 which moves over a scale 30 indicating the maximum rate. To prevent interference between the driving and releasing actions the duration of the driving impulse of the magnet 13 is fixed and shorter than the time during which each of the detents 14 ... 18 is disengaged. Contacts 31 are closed by the meter after a certain number of revolutions, and close the circuit of the magnet 13 and of a delayed-action relay 32, which opens its contacts 32a after a definite time interval. Another construction is shown in Fig. 4. A central spindle 38 is mounted in bearings in a front plate 55 and a rear plate 56. Five spindles, of which three 44, 45, 46 are visible, are equally spaced round the spindle 38 and mounted in bearings in the front plate 55 and an intermediate plate 58. Gear-wheels 33 ... 37 are mounted loosely on the spindle 38 and carry pegs 33a ... 37a which project through an aperture in the front plate 55 and engage the pointer 29. Gear-wheels 39, 40, 41 engage the gear-wheels 33, 34, 35, the gear-wheels 36, 37 being engaged by similar gear-wheels, not shown. The wheel 39 is mounted on a bush 60 turning freely on the spindle 44 and is biased by a coiled spring 6 to an initial position which is determined by the engagement of the pegs 33a ... 37a with the edge of the aperture in the front plate 55. Secured to the spindle 44 is a driving arm 7a carrying a pawl 7 normally held in engagement with a ratchet-wheel 1 by a spring. Similar arms and pawls are arranged on each of the other four spindles. Also secured to the spindle 44 is a gear-wheel 49 driven by a gear-wheel 54 which is secured to a bush 63 turning freely on an inner bush 65 freely mounted on the spindle 38. The other four spindles are similarly driven from the wheel 54. Also secured to the bush 63 is a ratchet-wheel 64 actuated by meter-controlled means corresponding to the electromagnet 13, Fig. 1. The bush 65 carries a disc 67 and a wheel 66, which may be continuously driven by an electric clock or may be driven by the ratchet-wheel 20, Fig. 1, the wheel 66 and disc 67 making one revolution in thirty minutes. The disc 67 carries a peg 68 adapted to come into position behind a member 69 freely mounted on the spindle 44. Six minutes later this peg lies behind a similar member on the spindle 45 and so on. The bush 65 is reciprocated axially by a cam and, through the disc 67 and peg 68, moves the member 69 axially against a spring 71 and then allows it to return to its initial position. Each driving arm 7a carries a projecting peg 72 having an inclined surface along which the member 69 slides when moved vertically thereby disengaging the corresponding pawl from the ratchet-wheel. Resetting the pointer to zero may be effected by rotating the scale thereby driving forward the wheels 33 ... 37 through the pegs 33a ... 37a until these are all brought to rest by engaging the edge of the pointer 29, which has previously been locked in position. The amount of movement of the scale is noted, the pointer freed, and the scale fractionally locked. Specification 5530/02, [Class 106], is referred to.