US2943158A

US2943158A - Two way lever type telephone key

Info

Publication number: US2943158A
Application number: US737050A
Authority: US
Inventors: Jean L Dubeau
Original assignee: Northern Electric Co Ltd
Current assignee: Nortel Networks Ltd
Priority date: 1958-05-22
Filing date: 1958-05-22
Publication date: 1960-06-28
Anticipated expiration: 1977-06-28

Description

June 28, 1960 J. L. DUBEAU 2,943,158

TWO WAY LEVER TYPE TELEPHONE KEY Filed May 22, 1958 5 Sheets-Sheet 1 1 #7 Due/15 -JEAN L. DUBEAU J 1 J. L. DUBEAU 2,943,158

TWO WAY LEVER TYPE TELEPHONE KEY Filed May 22. 1958 3 Sheets-Sheet 2 171067615 47 JEAN LDUBEAU mad 4. M

flw

June 28, 1960 J. 1... DUBEAU 2,943,153

TWO WAY LEVER TYPE TELEPHONE KEY Filed May 22, 1958 3 Sheets-Sheet 3 Y flue/2%? J54 1.2118540 United States Patent 2,943,158 'rwo WAY LEVER TYPE TELEPHONE KEY Jean L. Dubeau, Montreal, Quebec, Canada, assignor to Northern Electric Company, Limited, Montreal, Quebe'c, Canada, a corporation of Canada Filed May 22, 1958, Ser. No. 737,050

3 Claims. (Cl. 200-1) This invention relates to switching keys and more particularly to two-way lever type keys employed in telephone equipment.

Keys of the nature to which this invention relates generally consist of a pivoted lever carrying actuating rollers of insulating material, for selectively operating sets of contact springs arranged on both sides of the lever. The operation of the springs is effected by actuating the lever to one side or the other for the purpose of rotating the rollers into the operative position of the respective contact springs. Keys of this structure suffer from the eifect of the rebound action, incident to the return of the key lever to its normal position, which produced momentary actuation of the non-operated spring assembly with a consequent disturbance of the circuit controlled by the latter spring assembly. In order to remedy this defect, it is customary to provide specially shaped springs, generally known in the art as shepherds crook springs, which act as a buffer or brake against the returning key assembly.

The main object of this invention is to provide an improved two-way telephone key having improved means for preventing the undesired disturbance of the nonoperated circuit elements when the key lever assembly is returned to its normal position.

A further object of this invention is to provide an improved two-way telephone key, having improved means for preventing the undesired disturbance of the non-operated circuit elements when the key lever assembly is returned to its normal position, which isbconomical to construct.

These and other objects of this invention are attained by providing a two-way operated key which includes in combination: a pivotally mounted lever member with spring contact assemblies disposed on both sides of a cam pivotally mounted on the lever, arranged for coaction with the springs, the lever and cam being pivoted in relation to each other and the cam being so shaped that the force transmitted to the spring contact assemblies by the cam, upon its return to its normal position, is reduced with respect to switching keys provided in the past.

A better understanding of the invention may be obtained by referring to the following description, taken in conjunction with the drawings, in which like numerals refer to like parts, in which:

Fig. 1 is an enlarged side elevation of a two-way locking or non-locking switching key, employing the invention, in the normal non-operated position;

Fig. 2 is a section taken at 2--2 of Fig. 1 in the direction of the arrows;

Figs. 3, 4, 5 and 6 are enlarged partial side elevations of the positions which the elements of the switch, employing the invention, assume as the cam is actuated from its normal position in the direction shown; and

Fig. 7 shows one greatly enlarged cam, used in the invention, employed in explaining the invention.

Referring now in detail to the drawings, the key com- Patented June 28, 1960 prises a key frame 1, partially shown; lever 2,having handle 3 and projections 4, 5, projection 4 extending a predetermined distance upwards with respect to the projection so that .the key is in the locking and non-locking position when the handle 3 is actuated clockwise and counterclockwise respectively, pivoted on frame 1 by pin 6; a cam 7 made of electrical insulating material such asnylon, pivoted on lever 2 by the pin 8, having principal pairs of edge faces 9, 10 and 11, 12, the individual faces of each pair being disposed at an angle to form the contact points 13 and 14' respectively,

edge faces

9, 10 and 11, 12 being slightly curved; a set of spring contact assemblies, generally shown as 15, 16, each comprising

normal springs

17, 18, given a slight tension and having their

free ends

19, 20 formed at 21, 22 respectively, ata predetermined angle with respect to the center line of.

the

springs

17, 18, contact

springs

23, 24, for making contact with

normal springs

17 and 18, the spring contact assemblies being separated by insulator 25. Cam 7 may be formed with other suitable configurations.

In the normal unoperated position as shown in Fig. 1, the

free ends

19, 20 of the

springs

17, 18 rest on the

points

13, 14 of the

sides

9, 10 and 11, 12 respectively.

Assume now that the handle 3 is moved from the left to I On further movement of .the handle 3 from left to right, the free end 19 of spring 17 remains tangent to the arc of the face 9 of the cam 7, the center point 19 pressing against the free end 19 of spring 17 thus actuating the normal spring 17 and the associated contact spring 23 into their make position, as shown in Fig. 5.

On still further movement of the handle 3, face 9 of cam 7 slides on the free end 19 of spring 17 on the tangent point 19' until the travel of cam 7 is arrested by the projection 5. striking against the under side of the frame 1 as in Fig. 6. The key'n'ow locks in this operated position due to the imaginary line through the

pins

6 and 8 cutting free end 19 at a point more than halfway from spring 17.

When the handle 3 is released so that the switch is returned to its normal unoperated position, Fig. 1, due to the surface frictional sliding action of the free end 19 of spring 17 on the cam 7, the action being the reverse of when the handle 3 was moved from left to right as described heretofore, the return of the cam 7 is delayed so that the force with which the cam 7 strikes the free end 20 of spring 18 is reduced, thus diminishing the disturbance to the circuit elements associated with spring 18. The friction must be only sufiicient to permit the sliding action between the free end 19 of spring 17 and the cam 7.

,By disposing the projection 4 above projection 5, i.e. closer to the underside of frame 1, the distance that the cam 7 travels when the handle 3 is moved from right to left is decreased, thereby making the switch non-locking in this position.

What is claimed is:

l. A telephone switching key comprising in combination: a support; a plate-like lever pivotally mounted on the support; a plate-like rotatable cam of insulating material, pivotally mounted at its upper end on the lever, having two opposite edge faces arranged at an angle with each other; spring contact assemblies individually disposed adjacent =the edges faces, each assembly including a main spring inwardly deflected and outwardly otfset at its free end, with respect to the longitudinal center line of the cam, to form a point of contact with an edge face of the cam, the friction between the said edge face and the free end of the main spring being only suf ficient-to permit the sliding of such elements with respect 5 to each other when the key is operated.

2. A telephone switching key comprising in combination: a support; a plate-like lever pivotally mounted on the support; a cam of insulating material, pivotally mounted at its upper end on the lever, having two of its 10 opposite edge faces arranged at an angle with each other; spring contact assemblies individually disposed adjacent the edge faces, each assembly including a main spring inwardly deflected and outwardly offset at its free end, with respect to the longitudinal center line of the cam, to 1 4 form a point of contact with an edge face of the cam; the friction between the said edge .-faceand the. free end of the main spring being only sufiicient to permit the sliding of such elements withrespect to each other when the key is operated.

3. A telephone switching key in accordance with claim 1 in which the said lever is provided with ears integral therewith, disposed at its outer extremity and arranged to limit the travel "of the lever when it is operated;

References Cited in the file of this patent UNITED STATES PATENTS MacDonald Mar. 23, 1954 Barber Dec. 13, 1955