US2844655A - Motor-driven rotary telephone switching mechanism - Google Patents

Description

July 22,1958 F. SOMMER m, 2,844,655

MOTOR-DRIVEN ROTARY TELEPHONE SWITCHING MECHANISM Filed Jan. '18, 1952 2 SheetsSheet 2 Fig.2

United States Patent MOTOR-DRIVEN ROTARY TELEPHONE SWITCHING MECHANISM Friedrich Sommer, Berlin-Nikolassee, and Helmut Hofmann and Hans Eder, Munich, Germany, assignors to Siemens & Halske Aktiengesellschaft, Munich, Germany, a German corporation Application January 18, 1952, Serial No. 267,070 Claims priority, application Germany March 14, 1951 6 Claims. (Cl. 179--27.51)

This invention is concerned with the arrangement and construction of cam controlled contacts for governing certain operations of a motor driven rotary telephone switch of the type described in copending application Ser. No. 269,224, filed January 31, 1952, now Patent No. 2,701,824, issued February 8, 1955.

A switch of this type is provided with a drive motor comprising two alternately operable drive magnets for rotating in a steady continuous motion an armature which in turn rotates a drive wheel provided with a carrier from which extend wipers for selective engagement with bank contacts. Drive motors of this kind are described in Patents Nos. 2,002,546 and 2,654,846. The operative actuation of the drive magnets to cause rotation of the armature and therewith rotation of the drive wheel to rotate the wipers is governed by contacts controlled by the shaft on which the armature is mounted. The stopping of such a switch is effected by simultaneously energizing both drive magnets. An example of a control circuit for the drive magnets of such a motor-driven rotary switch may be had from Patent No. 2,691,699.

Certain steps or positions of such a switch, which may be used as a group selector or as a connector, or, rather to say, certain contacts thereof are used for marking intermediate resting or control positions so as to govern the switch in its operation with respect to its bank contacts. It must be considered in this connection that such a switch is purely a rotary switch as distinguished from switches, for example, of the Strowger type, in which the wipers are raised vertically to a desired level (decade-tens selection) and thereafter rotated in such level to establish engagement with desired bank contacts (unit selection). In the motor-driven switch, there may be several sets of vertically successively disposed wipers for selective engagement with associated sets of bank contacts disposed similarly in vertically successive groups. Accordingly,

- there is no vertical raising of the wipers but only rotation thereof. It the switch is used as a group selector, the set of wipers coacting with a certain group of bank contacts are responsive to dial pulses rotated to a position in engagement with the first set of contacts in such group and thereafter hunt for idle bank contacts (trunk) in such group. If the switch is used as a connector, the wipers are rotated to the desired group of bank contacts and thereafter rotated in such group to select the desired line, both phases of rotation being controlled by dial pulses. Special controls are accordingly required in 'order to synchronize the operation of the switch with the transmission of dial pulses. There are also required normal contacts, that is, for designating the normal position of the switch so as to control the homing operation thereof. All these contacts which are necessary for controlling the wiperposition-ing operations of the switch are governed by one or more cam wheels which rotate in synchronism with the drive wheel of the switch. The functions of some of these cam controlled contacts may in a descriptive sense be likened to the functions of the-vertical off-normal and the rotary olf-normal contacts in a Strowger switch.

The cam contacts were previously actuated directly by the cam wheels and were accordingly disposed tangential thereto. Access to the contact points and adjustment thereof is in such prior structures difficult, and the proper operation of the contacts cannot be easily observed. Ohattering of the contacts also occurs, due to the direct actuation thereof by the cam wheels.

The object of the invention is to avoid these drawbacks by arranging and constructing the contacts controlled by the cam wheels (decade contacts, control position contacts and normal contacts) in the switch frame in a par ticularly simple and easily accessible manner radial of the switch axis and by actuating them through the medium of cam levers which are pivotally disposed on the switch frame and operated by associated cam wheels. The contacts are thereby so arranged that the soldering terminals face inwardly, while thecontact points face outwardly. The contacts are disposed on an arcuate, approximately semi-circular line opposite the 'bank contacts of the switch. The cam controlled lever, which actuates the normal contacts, may also be employed as a pointed coacting with an indicia-carrying member for indicating the switch positions. The indicia member is preferably formed in the manner of a frusto-conical ring so as to facilitate the observation of the operating positions of vertically superposed switches, and particularly the observation of switches disposed in lower levels.

The various features of the invention will become ap parent from a description of the accompanying drawings, in which Fig. .1 shows a simplified perspective view of the driving mechanism of a switch; and

Fig. 2 is an elevational bottom view thereof.

In the switch frame 1 is disposed the stationary shaft 2. Rotata'bly journalled on the shaft 2 is the drive wheel 3 on which is fixed the wiper carrier 4. The drive wheel 3 is rotated in the direction of the arrow by the stepping motor having the field coils '11. These field coils operate, an armature, as described before, and the armature rotates upon actuation, a suitable gear which meshes with gear teeth provided on the drive wheel 3 peripherally thereof.

The wiper carrier 4 is in its upper portion shaped in the manner of a cross bridge, the shaft 2 extending through holes formed in the crossed parts thereof. The wipers 6, which are fastened on the carrier 4, sweep over the bank contacts (not shown), and their ends 7 are conductively connected with slip rings 8 which are disposed on the shaft 2 and connected by conductors included in the cable 9 (Fig. 2). On the drive wheel 3 isdisposed the cam wheel 10 forming the earns 11, 12 which coact, during the rotation of the drive wheel 3, with the cam levers 14, 15, 16. If desired, several separate cam wheels may be provided, one for each of the cam levers. As may be seen from Fig. 2, these cam levers are pivotally mounted on the pins 17, 18 and 19, respectively, which are disposed on the underside of the switch frame. Angular displacement of the cam levers by the associated cams causes operation of the coacting sets of contacts 20, 21 and 22, respectively. These contacts are fastened on the underside of the switch frame by screws 29 and extend in directions radial of the switch axis. The soldering terminals 1 of the contacts face inwardly, and the contact points face outwardly. The functions of the various sets of contacts 20, 21, 22 will depend on the particular switch.

The switch frame is provided with ribs such as 24, forming a protective recess for receiving the contacts. The cable carrying the conductors extending from the slip rings 8 and from the control contacts may also be disposed in this recess.

In order to indicate in a simple manner any operating position in which the switch may be, there is provided the indicia ring 25 which is rigidly connected with the drive wheel 6 coaxial therewith. This indicia ring is frusto-c-onical in shape, forming a downwardly sloping outside wall. The cam lever 14, which operates the normal contacts, also serves as a pointer for indicating the switch positions in coaction with the indicia ring 25.

The bushings 26, 27 are provided for receiving ad- 'justing pins associated with the mounting frame (not shown). Screws 2% serve for connecting the switch with the mounting frame.

Changes may be made within the scope and spirit of the appended claims.

We claim:

1. In a motor-driven rotary telephone switch having a frame and having a drive wheel rotatably mounted on said frame and a motor for rotating such drive wheel to rotate wipers relative to bank contacts disposed on one side of said frame, said drive wheel carrying cam means; a device for controlling the operation of said motor, said device comprising a plurality of sets of control contacts, means for mounting said control contacts on the underside of said frame, an operating lever for each set of control contacts, and means for pivotally mounting each operating lever for operative actuation by said cam means.

2. A structure and cooperation of parts according to claim 1, wherein each set of control contacts comprises contact spring means having terminals facing radially inwardly and contact points facing radially outwardly of said switch.

3. A structure and cooperation of parts according to claim 1, wherein a recess is formed in said frame on the underside thereof for receiving said sets of control contacts.

4. A structure and cooperationof parts according to claim 1, wherein said sets of control contacts are disposed opposite the bank contacts along an arcuate approximate semi-circular line radially spaced from the switch axis.

5. A structure and cooperation of parts according to claim 1, wherein one of said sets of control contacts constitutes the oil-normal contacts of said switch, a circular indicia-carrying member rotatable with said drive wheel, the operating lever for operating said off-normal contacts cooperating with said indicia-carrying member to indicate the position of the wipers with respect to the bank contacts of the switch.

6. A structure and cooperation of parts according to claim 1, wherein said sets of control contacts are disposed within a recess formed in said frame on the underside thereof and extending opposite the bank contacts along an arcuate approximately semi-circular line radially spaced from the switch axis, each set of control contacts comprising contact spring means having terminals facing radially inwardly and contact points facing radially outwardly of said switch, a circular indicia-carrying member rotatable with said drive wheel, one of said operating levers forming a pointer for cooperation with said indicia-carrying member to indicate the position of the wipers with respect to the bank contacts of said switch.

References Cited in the file of this patent UNITED STATES PATENTS 1,117,553 Craft Nov. 17, 1914 1,161,126 Grabe Nov. 23, 1915 1,375,762 Thompson Apr. 26, 1921 1,636,170 Chaplin July 19, 1927 1,978,700 Doring et al. Oct. 30, 1934 2,701,824 Ulrich et al. Feb. 8, 1955

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