US3659057A

US3659057A - Constant speed telephone dial return mechanism

Info

Publication number: US3659057A
Application number: US11440A
Authority: US
Inventors: Werner Poppendieck
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-02-14
Filing date: 1970-02-16
Publication date: 1972-04-25
Anticipated expiration: 1989-04-25
Also published as: DE1907544B1; CH496377A

Abstract

Mechanism for progressively balancing the unwinding spring tension of a telephone dial so as to effect a constant dialreturn speed and hence obtain a constant output pulse rate ratio from the telephone. An inner tubular cam face of spiral, repetitive wave form is swept by a brake consisting of a resiliently radially-outwardly-urged friction pin carried by the shaft of the dialing disk. An axially-directed drive pin also carried by the shaft is spring-urged to be (during dial return only) in driving relation with a unidirectionally rotatable toothed wheel which is jointly rotatable with a pulse wheel. Arrangement eliminates present spur gear, worm drive, and centrifugal regulator.

Description

[ 51 Apr. 25, 1972 [54] CONSTANT SPEED TELEPHONE DIAL RETURN MECHANISM [72] Inventor: Werner Poppendieck,

Reinerzstrasse

16, 1

Berlin 33, Germany [22] Filed: Feb. 16, 1970 [21] Appl. No.: 11,440

[30] Foreign Application Priority Data Feb. 14, 1969 Germany ..P 19 07 544.6

[52] U.S.Cl. ..l79/90R FOREIGN PATENTS OR APPLICATIONS 867,122 11/1958 Great Britain ..l79/9O R Primary ExaminerKathleen H. Claffy Assistant Examiner-Tom DAmico Attorney-Howard L. Johnson ABSTRACT Mechanism for progressively balancing the unwinding spring tension of a telephone dial so as to effect a constant dialreturn speed and hence obtain a constant output pulse rate ratio from the telephone. An inner tubular cam face of spiral, repetitive wave form is swept by a brake consisting of a resiliently radially-outwardly-urged friction pin carried by the shaft of the dialing disk. An axially-directed drive pin also carried by the shaft is spring-urged to be (during dial return only) in driving relation with a unidirectionally rotatable toothed wheel which is jointly rotatable with a pulse wheel. Arrangement eliminates present spur gear, worm drive, and centrifugal regulator.

4 Claims, 5 Drawing Figures PATENTED APR 2 5 1972 SHEET 10F 2 PATENTEnAPRzs r972 659 O57 SHEET 2 BF 2 FIG. 5

CONSTANT SPEED TELEPHONE DIAL RETURN MECHANISM This invention relates to an arrangement for progressively braking and uniformly regulating the return speed of signaling dials of dial telephones, thereby obtaining a constant-rate output signal.

Almost without exception, the known mechanisms of this kind use centrifugal regulators. These make it necessary for the assembly to transform the relatively slow dial-return speed to rapid motion. Only in this way can a dial return of about one second at a pulse rate of 60 to 40 ms and a total pulse of 100 ms be insured. The incorporated transmission elements consist in principle of a spur gear and worm drive located between the main shaft of the dialing disk and the centrifugal regulator; the shaft of the centrifugal regulator is thus parallel with the hole plate.

A spur gear and worm drive as well as the centrifugal regulator greatly increase the cost of the assembly. Therefore this invention is directed to eliminating the spur gear and worm drive and avoiding the centrifugal regulator. As noted in the preceding abstract, all these parts may be replaced by simpler components which consist of a spring-tensioned or resilient friction pin sliding on the particularly configured, inner tubular face of a cam ring; this results in a substantial simplification of the conventional dial sub-assembly.

The present solution to the problem is based on the observation that the force stored in the drive spring by winding or turning the dial, which force decreases uniformly to zero upon complete return of the dial to rest position and which force also uniformly decelerates the dial return, may be counterbalanced to produce an approximately uniform progression by use of a resilient friction pin carried by the dial. The resilient spring force of the pin-spring itself is also variable and this is applied in inverse proportion to the force of the unwinding drive spring, such brake force being produced by contact of the friction pin with the radially varying face of the cam ring so as to provide a constant dial return speed and thus to assure a constant pulse rate.

A presently preferred embodiment of the invention is illustrated by way of example in the accompanying drawings wherein FIG. 1 is an elevational view of the dial face of the unit.

FIG. 2 is a side elevational view thereof.

FIG. 3 is a transverse sectional view taken through the unit of FIG. 2 along the line 33.

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2.

FIG. 5 is an enlarged axial sectional view with portions in elevation.

A fixed numeral-carrying plate 12 is spacedly overlaid by a rotary dialing disk 13 having the usual circle of finger apertures spaced above the sequence of numerals on the plate 12 in the customary manner, the plate and disk being connected by a return spring 5. The dialing disk is secured to a central shaft 2 by a headed bolt 14, the shaft being approximately coaxial with a tubular housing 11 which traverses the plate 12. Distally the shaft 2 is fixed to a lateral housing arm 15 which carries brake means in the form of a radially reciprocable friction pin 9 which is urged outward by a helical spring 4 so as to position the outer end of the pin in sliding registration with the radially-varying inner face of a cam ring 3. The latter is fixed to a support 16 and as seen in FIG. 4, its inner contact face takes the form of a wavy, parabolic spiral whose radium increases in the return direction of the dial 13. When the telephone user is dialing (clockwise in FIG. 1), the brake force of the cam ring 3 progressively increases, and at the same time spring tension is accumulated in the dial return spring 5. When the user then releases the dial 13, the result is a very uniform or constant unwinding or return of the dialing disk 13 due to the balancing of the spring tension of 5 and the brake pressure of the friction pin on the cam face 3.

Still more distal from the dial face is a sprocket wheel or toothed annulus 7 and a peripherally-lug-projecting wheel 10 axially spaced apart and fixedly connected to ether by a tubular shaft 17 which is generally coaxial with t e upper shaft 2.

The

members

7, 10, 17 are jointly rotated by an axiallydirected drive pin 8 during return of the dialing disk 13, the pin being reciprocably housed in a socket 18 of a diametric extension 19 of the radial arm 15, such rotation thus actuating the pulse transmitter l. The drive pin 8 is maintained in contact with the toothed rim of the sprocket wheel 7 by a coil spring 20. It will be seen that the parabolic wave form of the cam face 3 corresponds to the uneven load through the pulse transmitter resulting from return movement of the dial following the traversing each pulse intermission during which the pulse transmission is not actuated by the wheel 10. Thus the unwinding wave pattern for the friction pin 9 produces an approximately uniform decrease of the frictional braking force. The advantages of such simplified construction over that of the prior art should be apparent.

I claim:

1. in combination with a pulse-activating dial telephone having a spring-restrained rotary dialing disk normally returnable to rest position by release of spring tension which has been accumulated by dial rotation, the improvement comprising a counterbalancing second tension means operative in response to return rotation of said dialing disk and adapted progressively to brake said released spring tension in inverse proportion to its decreasing force so as to effect a constant dial-retum speed and thereby assure a constant output pulse rate from the telephone, said second tension means including radially-varying cam ring means and substantially radially directed brake means disposed to frictionally follow the radially-varying curvature of the cam ring means, one of the pair of cam ring means and brake means being carried by the rotary dialing disk.

2. The combination of the preceding claim 1 wherein said cam ring means comprises a cam face of substantially spiral form and said brake means comprises a substantially radially tensioned friction pin carried by a rotary shaft of said dialing disk and resiliently retained in sliding contact with the spiral face of said cam ring means.

3. The combination of the preceding claim 2 wherein said spiral cam face is characterized by a repetitive wave pattern and the radius of said spiral increases in the direction of dial return.

4. The combination of the preceding claim 2 which additionally includes pulse transmitting connecting means com prising a unidirectionably rotatable toothed annulus and a drive member connected to said rotary shaft and functionally retained in drive relation with said annulus only during return movement of said dialing disk.

a a a a UNITED STATES PATENT OFFICE QER'HFECATE 0F CGRECTWN Patent No. 3, 659 O57 Dated April 25 1972 Invent' (s) Werner Poppendieck It is certified that error appears in the above-identified patent and that said Letters Patentare hereby corrected as shown below:

Column 2, line 2, radium" shoulfi read radius lines 23-24, cancel "following the" Signed and sealed this 12th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM P0-10 0 (10-69) USCOMM-DC cows-P59 US. GOVERNMENT PRINTING OFFICE [9G9 0-366-385.

Claims

1. In combination with a pulse-activating dial telephone having a spring-restrained rotary dialing disk normally returnable to rest position by release of spring tension which has been accumulated by dial rotation, the improvement comprising a counterbalancing second tension means operative in response to return rotation of said dialing disk and adapted progressively to brake said released spring tension in inverse proportion to its decreasing force so as to effect a constant dial-return speed and thereby assure a constant output pulse rate from the telephone, said second tension means including radially-varying cam ring means and substantially radially directed brake means disposed to frictionally follow the radially-varying curvature of the cam ring means, one of the pair of cam ring means and brake means being carried by the rotary dialing disk.

4. The combination of the preceding claim 2 which additionally includes pulse transmitting connecting means comprising a unidirectionably rotatable toothed annulus and a drive member connected to said rotary shaft and functionally retained in drive relation with said annulus only during return movement of said dialing disk.