Patent GB-195954-A (GB)
Title: Improvements in apparatus for the measurement of speed or frequency of oscillations of moving parts
IPC: G01P3/02
Filed: 1923-03-22
Abstract: 195,954. Seguin, A. April 8, 1922, [Convention date]. Impulse and momentum speed indicators; speed-indicator transmission mechanism. - The oscillations imparted to an arm 4, Figs. 1 and 2, by the member whose speed is to be measured are compared with those of another arm 5 moved in one direction by the arm 4 and in the opposite direction by a pin d' on a balance-wheel d oscillated by a spiral spring s. The arm 5 is freely mounted on the hub of the balance-wheel d, and the arm 4 carries a pivoted hook 11 held in the operative and inoperative positions by a spring 14 engaging on either side of a tail-piece 15. The indicating-hand e carries an extension 8<1> provided with a pin 8 adapted to be engaged by the hook 11 or by the striker arm 5, and is held stationary between such engagements by means of a friction washer r, Fig. 2. When the arm 4 moves counter-clockwise, Fig. 1, the hook 11 engages the pin 8 and moves the hand e, until a pin 13 on the hook rides up a slope 1 on the arm 5 to cause the hook to be released. The arm 5 is now moved by the arm 4 and engages the pin d<1> on the balance-wheel to wind up the spring s, until the arm 5 meets a stop such as a pin 17. The balance-wheel is free to continue its movement until damped by its spring, and the arm 4 moves in the opposite direction without engaging the pin 8. At the end of the clockwise movement of the arm 4 the pin 13 rides on an inclined surface of the pin 17 to restore the hook 11 to its operative position ready to re-engage the pin 8. The meeting-point of the striker arm 5 in its clockwise movement and of the arm 4 in its counter-clockwise movement thus determines the position of the indicating hand. In a modification, Fig. 3, the arm 5 is latched by a spring hook 26 while the arm 4 is moving clockwise, and is released by the engagement of a projection 28 on the arm 4 with a cam 28<1> on the spring hook. The arm 4 may be attached to a wheel 10, Fig. 2, loosely mounted on a stud 2 and engaging a rack on a piston 45 reciprocated in a cylinder 6 under pneumatic impulses transmitted from the member whose speed is to be measured. The balancewheel and striker arm may be mounted in the manner described in Specification 184,289 instead of as shown in Fig. 2. In a further modification, shown in Figs. 4 and 6, the striker arm 5 and the index arm 8 may be engaged by a hook member 11 carried directly on a reciprocating piston 54. The hook is brought to the operative position by engagement with a stop 34 and to the inoperative position by engagement with the striker, as described above. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter :- Speed-indicator transmission-mechanism.-The pneumatic impulses may be transmitted to a bellows 55, Fig. 5 (Cancelled), connected through a toothed sector to the wheel 10. The bellows may be fitted with a valve 24 opened and closed by stops 21, 22 and with a spring 5<1>. Or a reciprocating piston with a valved cap opened and closed by stops may be employed for receiving the impulses. The impulses may be created by a piston pump reciprocated in one direction by a cam and in the other by a spring. This subject-matter does not appear in the Specification as accepted.