GB415285A - Improvements in and relating to electric switching apparatus with time-delay action - Google Patents

Abstract

415,285. Retarding action of switches. PARSONS & CO., Ltd., C. A., and TOPHAM, H. B., Heaton Works, Newcastle-on-Tyne. Nov. 11, 1933, Nos. 31507 /33 and 3340/34. [Class 38 (v).] A motor-driven time-delay switch-actuating mechanism comprises an axially-slidable and rotatable clutch member adapted to be axially moved by a contact-carrying lever or arm to engage with and be rotated by a motor-driven element through an arc of movement predetermined wholly or in part by the angular setting of a timing element not in driving relation to the motor-driven element. As shown in Fig. 1 the time setting is effected by a flanged disc 14, 15, having holes into which project pins 13 attached to a grooved collar 12. The collar 12 carries a plate 16 formed with notches 17 (Fig. 2) and is loosely mounted on a geared shaft driven from a self-starting synchronous motor 30. The groove 11 in the collar 12 is engaged by a forked projection 9, 10 of an arm 8 of a three-armed lever pivoted at 6, the arm 5 being held in the position shown by the core 2 of a normally-energized electromagnet 3. When this electromagnet is de-energized by the opening of a switch 40 in the primary circuit of transformer 64 the counterweight 7 rotates the lever 4, 5, 6, in a clockwise direction. This has the effect of sliding the collar 12 to the left and the disc 16 engages the ends of projections 27 carried by a clutch member which is also slid to the left. A crown wheel 29 driven through gearing from the motor is engaged by a tooth 28 on the clutch member. The collar 26 on the clutch member has a groove 25 engaging the forked end 23, 24 of an arm 22 depending from a weighted lever 20 the rotation of this lever due to the sliding of the clutch member causing the completion of the motor circuit by the contact 37 bridging its upper contacts. The motor thus drives around the clutching members until the projections 27 carried thereby come opposite the slots 17 of the diso 16, the time which elapses before this occurs being determined by the initial angular setting of the disc 16 as indicated by the scale 15. When this occurs the clutching-member slides bodily to the right under the action of the counterweight 34 of lever 20 and disengages the clutching members 28, 29. A controlled circuit 19 is then completed through seriesconnected contacts 19<a>, 19<b> and this is maintained closed until the electromagnet 2 is again energized by closure of switch 40. On this occurring the parts are restored to the positions shown, the clutching member being restored by gravity to its initial position owing to the attachment thereto of a weighted arm 31 carrying at its end a ball race 33. In a modified form (Fig. 4) one of the pivoted levers may be dispensed with, the lever 43 having an intermediate position in which contacts 47, 48 are bridged. The projections 56 on the sliding member 54 engage the teeth of a wheel 59 and the clutch member is thereby rotated by the energized motor 30. The member 54 carries rollers 58 which ride on the surface of the adjustable turning disc 61 until at the expiration of the prescribed period the rollers 58 came opposite slots 62 in the disc 61 when the lever 43 moves to its final position bridging contacts 48, 49 and the motor circuit is automatically broken. The contact arrangement may however be varied to close a controlled circuit for a predetermined period or to produced timed intermittent closures and openings of the circuit. Specification 414,647, [Group XXXV], is referred to.