Patent GB-428738-A (GB)
Title: Improvements in or relating to operating mechanism for automatic electric circuit-breakers
IPC: H01H71/58
Filed: 1934-06-22
Abstract: 428,738. Electrically - released switches. SCHIELE & BRUCHSALERINDUSTRIEWERKE AKT. - GES., Baden- Baden, Germany, and CRABTREE & CO., Ltd., J. A., Lincoln Works, Walsall. June 22, 1934, No. 18440. Convention date, June 22, 1933. [Class 38 (v)] An operating and free-handle mechanism comprises a manually-operated driving member, a driven member carrying or connected to the movable contact, and a coupling member which is pivoted to, and movable collectively with, the driven member and also shiftable transversely thereto during operation of the driver. A locking member co-operates with the latter for gripping the shifted coupler in the " on " position, and the gripping means is so arranged that it can be freed from the coupler either by manual operation of the driver to open position or by automatic displacement of the locking member. The driving member a is pivoted at b and carries a roller a<1> taking in a notch t on a cam surface d<1> of a disc-like coupling d, which is pivoted at f to the driven member c, the pivot of which is coaxial with b. To reduce the bulk, the member c has a cavity c<2> containing the member a and a light spring o connected between it and a pin p on member c. The latter has a grooved periphery housing a spring l which is anchored between a pin m on the member c and a pin n on a locking member g. The spring l acts to move c anticlockwise or " off " and to move g anticlockwise about its pivot i so that a roller h engages a cam surface d<2> with a notch v. A semi-cylindrical pin r acts as a detent for a tongue g<1> on g, and a further tongue g<2> acts to restore the locking connection between g<1>, r during the opening movement. To close the breaker from the " off" position (Fig. 1), a, a<1> is rotated clockwise and by means of t rotates the coupling d. Due to the pivot f and the engagement between hand cam d<2> on the coupling d, the driven member c is also rotated clockwise. At the closed position, the notch v comes level with h, so that the pressure of a<1> on the recess t forces d to rotate anticlockwise about f, and a<1> rides out of t on to the cam d<1>. In this position, Fig. 2, v, h engage and d<1>, a<1> engage, so that further movement of d about f cannot take place and therefore l cannot open the breaker. Further, the friction between a<1>, d<1> is too great for the spring o to retract a<1> until the member a is moved backwards for manual opening. When the latter occurs, a<1> re-enters t and the spring l causes the notch v to push past the roller h, whereupon c, d, a rotate together to the " off " position. The detent r is also rotatable by a thermal release, and, by releasing g, breaks the latch connection h, v, whereupon c, d move to " off position, followed by a under action of the tensioned spring o. Fig. 4 shows a rectilinearly-sliding driver a notched at a<1> to receive the end d<1> of a coupling d which is pivoted to the driven member c. Due to locking-member g, the parts a, c, d move together until. h comes level with d<2>, whereupon a pushes past d<1> and urges h, d<2> into engagement. The frictional force on a is too great for o to restore it. For manual opening, s is pulled back, and for automatic opening r is rotated to free g. In Fig. 5, (not shown), a roller on a engages a notch on d, whereas in Fig. 6, (not shown), the member c is formed with a cage for a ball or roller serving as a coupling by engaging a recess in a until it comes level with a recess in g. In both these forms the action is similar to that of Fig. 4.