Patent GB-741889-A (GB)
Title: Improvements in means for indicating or recording the extent of an element
Inventor: LAST JAMES
IPC: G06M3/06
Filed: 1953-08-15
Abstract: 741,889. Counting-apparatus. ELLIOTT BROS. (LONDON), Ltd. Aug. 16, 1954 [Aug. 15, 1953], No. 13736/53. Class 106 (1). Means for indicating or recording the extent of rotation of a rotary member comprises a units wheel, gearing connecting the wheel and the rotary member in such a manner that the wheel would normally be advanced through one digit pitch for each rotation of the member through an angle representing a unit value of the quantity or value to be indicated or recorded, a detent normally holding the wheel against rotation, an element in the gearing adapted to be displaced from an initial position against the action of restoring means when the rotary member rotates while the wheel is stationary, and means arranged to render the detent means inoperative at unit value intervals of the rotation of the rotary member so that the restoring means may return the gearing element to its initial position and thereby cause the wheel to advance through one digit pitch. The meter spindle 1 carries a gear 9 which meshes with a pinion 8 on a spindle 7 carrying a pinion 6 which meshes with a gear 5 attached to the units drum 2 which bears two series of numerals and is mounted on a spindle 4 coaxial with the spindle 1. The spindle 7 is mounted in a planetary U-shaped frame 11 the limbs 10 of which are rotatably supported on the spindles 1, 4 respectively. A ratchet 13 is also fixed to the spindle 4. A lever 32 has at one end a detent 14 which normally locks the ratchet 13 and the drum 2. The other end of the lever 32 is connected by a link 31 to a T-shaped lever 27 pivoted at 28 to an arm 15 extending from the frame 11. A pin 17 extends from the arm 15 between two levers 22, 23 urged together by a spring 26 and pivoted to an arm 16 extending from the spindle 1. Two pins 18, 19 between the levers 22, 23 extend from the arm 16 and pass through holes 20, 21 in the arm 15. A cam 40 having two parts 44, 45 of different radii joined by stepped parts 46, 47, 48 is fixed to the spindle 1. A roller 41 carried by a lever 42 rides on the cam 40. The lever 42 is mounted at one end of a spindle 39 on the other end of which is an arm 38 having a pin 37 which engages a cam slot 36 in the arm 16. Initially the roller 41 is on the step 47 of the cam 40 and the drum 2 is at zero. Rotation of the spindle 1 in either direction by an amount corresponding to half of a unit causes movement of the linkage 42, 39, 38, 16 and one of the pins 18, 19 moves the T-shaped lever 27 so that the lever 32 is moved to such an extent that the detent 14 moves half way out of the adjacent notch in the ratchet 13. At the same time the half unit rotation of the spindle 1 is transmitted to the planetary frame 11 the arm 15 of which also moves the T-shaped lever 27 and the lever 32 connected thereto. The pin 17 separates the levers 22, 23 and stresses the spring 26. The two movements of the lever 32 are additive so that after an initial movement of the spindle 1 by an amount corresponding to half a unit the detent 14 frees the ratchet 13 whereupon the spring 26 through the levers 22, 23 and the pin 17 returns the frame 11 and the drum 2 is rotated through the gears 6, 5 by one unit. The units drum is connected to the tens drum 3 through transfer mechanism 49, 51, 53, 54. The direction of the initial movement of the lever 42 is determined by the direction of rotation of the meter spindle 1 and the lever 42 effects, through a mechanism, not shown, relative movement between the drums 2, 3 and their viewing windows so that the correct series of numerals on each drum is visible. The detent 14 thereafter arrests the ratchet 13 and drum 2 until the planet carrier 11 has moved through a distance of one unit. The wheels 2, 3 may be replaced by type-wheels where the extent of rotation of the spindle 1 is to be recorded.