Patent GB-409685-A (GB)
Title: Improvements in and relating to control apparatus employing tooth and pawl mechanism
IPC: B21B37/60
Filed: 1932-10-27
Abstract: 409,685. Control of motors. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.-(Assignees of Allgemeine Elektricitõts-Ges.; 2, Friedrich Karl-Ufer, Berlin.) Oct. 27, 1932, No. 30180. Convention date, Oct. 27, 1931. [Class 38 (iii).] Travelling to predetermined limits. -In control apparatus for making adjustments for given movements by means of a disc, roller band or the equivalent, provided with teeth, the releasing member or pawl engaged by the teeth possesses two degrees of freedom. In the arrangement shown in Fig. 1, on closing a push-button 5, an electromagnet 6 is energized and attracts a lever 4 carrying a pivoted contact-carrying pawl 3 normally held out of engagement with a contact 7 by a tooth 2 on a disc 1 coupled to the drive for the part to be adjusted. When the lever 4 is attracted, the pawl 3 drops on to the contact 7, and the adjusting motor 8 rotates until its circuit is broken by the engagement of the next tooth 2 with the pawl, which has been restored to its normal position by a spring 9 on release of the push-button 5. In a modification, Fig. 2 (not shown), where a large number of teeth are required, the teeth are arranged on a band. In another arrangement, Fig. 3, the lever 11 and pawl 12 are arranged in the form of shears, and constructed to carry the contacts. In another construction, Fig. 4 (not shown), the pawl is connected to a bridging-contact by a rod. In a further modification, Fig. 5 (not shown), the pawl imparts movement to a lever pivoted at a fixed point and carrying a contact, and the counter contact is moved forward from the contact controlled by the pawl and is only returned to its original position when the controlling force ceases. In the arrangement shown in Fig. 6, the pawl 29 is carried by a slide 30, one movement of the pawl being effected by raising the slide under the influence of the electromagnet 6, while the other movement is caused by a spring 34. The slide is supported by means of a slot upon the spindle 31 of the tooth disc 1, or upon the spindle of a wheel which drives a chain or band provided with teeth. In other arrangements, the releasing member frees a mechanical driving mechanism. In one. such arrangement, Fig. 7, for controlling the striking mechanism of a clock, a disc 39, continuously rotated at a slow speed, engages a roller 42 and moves the pawl-lever 38 in a horizontal direction, thereby releasing a vane 40 and allowing a disc 49 to rotate until a tooth 2 thereon engages the pawl 43 to raise it. By means of a guide 51 and a spring 52 engaging a projection 53 on the lever 38, the latter is rotated in a clockwise direction to release the roller from the depression in the disc 39 and cause the re-engagement of the pawl 43 with the vane 40. In a modification, Fig. 8, the tooth 53 is secured to a spindle 54 on which the disc 39, driven at a constant speed, is loosely mounted. The tooth 53 is connected to the disc by a spring 56. When the pawl-lever 60 is moved to the right by the disc, the vane 40 is released to allow rotation of the spindle 54 by the spring 56 until the tooth 53 engages the pawl 59 and raises the lever 60, which thereupon moves to the left under the influence of a spring 61 and prevents further rotation of the vane. Reference has been directed by the Comptroller to Specifications 7883/07, [Class 38], 328,700, [Class 38 (iii)], and 352,602.