GB315951A - Improvements in or relating to supporting arms for gramophone "pick-up" devices and to means for mounting such devices in their supporting arms - Google Patents

Abstract

315,951. Electramonic Co., Ltd., Tyrrell, S. J., Sayers, D. W., and Tyrrell, L. N. May 24, 1928. Electric pick-ups and the like, supporting.-An electric gramophone pick-up or like reproducer or recorder is connected to a supporting arm by means of a plug and socket having interfitting electrical contacts. The socket may be provided on the end of the arm, and the plug on the pickup, or vice versa. In each of the various constructions shown, the pick-up 8 is provided with a plug 11 which projects from the casing of the pick-up and engages in a socket member secured in the end of the supporting arm 1. Contacts of various form may be provided in the socket, the number, form, and arrangement of the contacts being suited to the particular construction of plug employed on the pick-up. For example, in the socket shown in Fig. 1, a metal sleeve 19 and a spring-pressed plunger 20 are provided in an insulating block 18. The sleeve 19 is connected to a lead 23 running through the supporting-arm 1, and when the plug is inserted therein it makes direct contact with the plug, to which one end of the winding of the pick-up is connected. The other end of the winding is connected to the casing of the pick-up which, when the plug is in the socket, makes contact with an end plate 21 on the supporting arm. Figs. 8 and 9 show examples of sockets for use with a plug made in two separate insulated parts, each of which is connected to one end of the pick-up winding. The parts 12, 13 of the plug contact respectively either with the blades 32, 32<1>, Fig. 8, or with the plunger 20 and sleeve 19, Fig. 9. For retaining the pick-up in either the operative position or rotatably displaced for needle-changing, a spring-pressed ball catch 29 may be provided in the end plate of the socket member, to engage in recesses in the pick-up casing. The supporting arm 1, Fig. 1, is a hollow bar of channel section, pivoted at 2 on a rotatable post 3. A blade spring 38 fixed to the post 3 serves partially to counterbalance the weight of the arm and pickup. Specification 314,648, [Class 40 (iv), Telephones &c.], is referred to.