US3851113A

US3851113A - Finger stop for a movable finger stop-type rotary dial

Info

Publication number: US3851113A
Application number: US00377665A
Authority: US
Inventors: C Blackmon
Original assignee: GTE Automatic Electric Laboratories Inc
Current assignee: AG Communication Systems Corp
Priority date: 1973-07-09
Filing date: 1973-07-09
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26
Also published as: CA995834A

Abstract

An improved finger stop arrangement for a rotary dial is disclosed wherein the movable finger stop includes two stop arms which are diametrically opposed about the axis of the dial. These arms cooperate with a pair of projections extending upward from the base plate of the dial and provide dual stopping means for the finger stop.

Description

United States Patent i191 Blackmon, Jr.

[11'] 3, 1,11 Y Y [45] Nov. 26,1974

[ FINGER STOP FOR A MOVABLE FINGER [75] Inventor: Charles E. Blackmon, .lr.,

' Huntsville, Ala.

[73] Assignee: GTE Automatic Electric Laboratories Incorporated, Northlake, 111.

[22] Filed: July 9, 1973 [21] Appl. No.: 377,665

52 us. Cl. 179790 FW [51] Int. Cl. H04m 1/23 [58] Field of Search 179/90 R, 90 FW, 90 A, 179/90 AT [5 6] References Cited UNITED STATES PATENTS 2,905,766 9/1959 Soderbaum 179/90 R STOP-TYPE ROTARY DIAL 3,108,159 10/1963 Mattke 179/90 R 3,391,245 7/1968 Dal Monte et a1 179/90 'R 3,525,821 8/1970 Pulles 179/90 R Primary Exafniner-Wi1liam C. Cooper Assistant Examiner-Gerald L. Brigance Attorney, Agent, or FirmDavid W, Hcid [57] ABSTRACT An improved finger stop arrangement for a rotary dial is disclosed wherein the movable finger stop includes two stop arms which are diametrically opposed about the axis of the dial. These arms cooperate with a pair of projections extending upward from the base plate of the dial and provide dual stopping means for the finger stop.

4 Claims, 2 Drawing Figures Babb et a1 179/90 R SHEET 2 BF 2 PATENTEL HSVZBISM FINGER STOP FOR A MOVABLE FINGER STOP-TYPE ROTARY DIAL BACKGROUND OF THE INVENTION This invention relates generally to rotary dials used in telephone instruments, and more particularly to the type of rotary dial in which the finger stop is movable within a predetermined angular range.

Rotary dials with a movable finger stop per se are well known in the art as is evidenced by US. Pat. No. 3,108,159 issued to C. F. Mattke on Oct. 22, 1963, US. Pat No. 3,105,122 issued to J. G. Babb et al on Sept. 24, 1963 and US. Pat. No. 3,525,821 issued to E. J. Pulles on Aug. 25, 1970. These dials have the advantage of 1 reduced size, which is accomplished by eliminating much of the previously required space between the fingerholes for 1 and the and providing a movable finger stop so that the finger wheel may be rotated through an angle greater than 360. The movable finger stop allows the dial shaft to be rotated more than 360 and hence insures the necessary spacing between the consecutive impulse series in the dial pulse signal train. With the advantage of reduced size there is also the disadvantage of amore complex dial mechanism.

Since in all these prior art patents mentioned above the finger stop is movable, it is important that the predetermined angle of movement of the fingerstop from its rest position to its fully rotated position be limited to insure that only the proper number of dial pulses will be sent out over the telephone line. In some of the prior art dials it has been found that the finger stop may be moved beyond the intended predetermined maximum rotation and hence the'dial rotated beyond its intended degree of rotation. This results insendingout an incorrect number of dial pulses for the digit dialed since the finger wheel will be moved through an angle greater than that which was set for the dialed digit.

SUMMARY OF THE INVENTION As was indicated in the preceding discussion it is very important that the finger wheel be allowedto only rotate the predetermined amount and hence not send out a false or incorrect series of dial pulses. In the present invention an improved finger stop arrangement is disclosed wherein primary and secondary fingerstop arms cooperate with a pair of projections to insure that the finger stop and hence the finger wheel may not be rotated greater than the predetermined angle.

The pair of stop arms of the finger stop in the present invention are located on opposite sides of the center of rotation and pivot point of the finger stop and hence any attempt to lift the finger stop over the cooperating projections for one of the arms will merely move the other arm of the finger stop down even further into en- FIG. 2 is a top plan view of the'rotary dial of the present invention withthe finger wheel removed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is illustrated,- in an exploded perspective view, the upper portion of a typical gagement with its corresponding stopping surfaces.

Hence it is impossible, short of destruction of the dial, to cause the finger stop to override the stopping surfaces built into the dial. The present invention may be advantageously employed in a miniature rotary dial of the general type illustrated in US. Pat. No. 3,525,821.

. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded view of theupper portion of a rotary dial which incorporates the improvedfinger stop arrangement of the present invention.

rotary dial in which the present invention maybe incorporated. In the interest of brevity, such items as the governor, impulsing contact springs, dial shunting contact springs and other associated items have not been shown since they form no part of the present invention. These and other necessary component parts of the rotary dial may be of the type illustrated in US. Pat. No. 3,525,821 and fully and clearly disclosed and described therein. Again referring to FIG. 1, the present invention will best be described by logical sequence in which the upper portion of the dial is assembled. First it will be noted that the main shaft 1 extends from the lower portion of the dial, the components of which have not been shown, up through aperture 2 in the mounting plate 3, main shaft 1 serving to transmit the rotation of the finger wheel to the usual components in the lower part of the dial. Onmounting plate 3 there is included a pair of

projections

4 and 5, these projections serving to limit the travel of finger stop 6- in addition to several other functions which will be described subsequently.

Projections

4 and 5 are preferably made from molybdenum disulfide filled nylon. Number plate 7 is positioned over mounting plate 3 and held into place thereon by means of locking ring 8 which is placed around

projections

4 and 5 on the top number plate 7 and then rotated with fingers 9 engaging notches 10 of

projections

4 and 5. Spiral main spring 11 is mounted within

projections

4 and 5 resting on mounting plate 3, with its outer end 12 engaging catch 13 located on the inner side of projection 4. Next hub 14 is positioned within spring 11, withnotch l5 engaged by the inner end 16 of the spring. Hub 14 is then rotated a predetermined number of turns in the clockwise direction to pretension spring 11 and is then pushed down over the top of shaft 1, with the key portion of shaft 1 engaging the corresponding portions of the center hub 14.

Coupling element 17 is then mounted over hub 14 with the inner key portions 18 of coupling element 17 engaged by the outer key portions 19 of hub 14. Movable finger stop 6 is then placed over, and rests on, the

outer flange of coupling element 17, with finger 20 10- cated on left side of tab 21. Friction washer 22 is positioned over coupling element 51 on top of finger stop 6 to frictionally couple the finger stop to coupling element l7 and hence to dial shaft 11. Finger wheel 23 is mounted on coupling element 17 with legs 24 of coupling element 17 engaging corresponding slots in finger wheel 23. A holding washer 25 is. positioned on finger wheel 23 with locking fingers 26 :at first resting on the top of legs 24.

C-shaped washer 27 is pressed into the keyed slot 28 of main shaft 1 to lock the assembly in position and then holding washer 25 is rotated approximately 60", as shown in FIG. 1. Fingers 26 now bear down on depressions 29 of ridges 30 to permanently hold finger wheel 23, friction washer 22, finger stop 6 and coupling element 17 on hub 14. A cap 30 is mounted on top of finger wheel 23 with spring elements 31 engaging corresponding slots 32 of finger wheel 23.

Also included on mounting plate 3 is a post 31 which cooperates with notch 32 in number plate 7 to insure that number plate 7 is oriented in the proper location. With finger stop 6 inserted in the proper position the primary arm portion 33 will be positioned between side 34 of projection 4 and side 35 of projection 5 and by virtue of main spring 11 cooperating with the various coupling parts primary arm portion 33 will normally rest against side 34. In this manner when the user rotates finger wheel 23 finger stop 6 will rotate from side 34 and its clockwise rotation be limited by side 35 of projection 5.

A secondary stopping arrangement has been included in finger stop 6 by virtue of a secondary arm portion 36 of finger stop 6. This secondary stopping arrangement functions in conjunction with side 37 of projection 4 and side 38 of projection 5. Thus, when the main spring 11 rotates hub 14 and hence coupling element 17 counter clockwise the finger stop 7 by virtue of finger 20 being on the left side of tab 21, is rotated in a counter clockwise direction such that primary arm portion 33 is urged against side 34 and secondary arm portion 36 is urged against side 38 of projection 5. When the user rotates finger wheel 23 in the clockwise direction to dial one of the digits, finger stop 6 will be also rotated in a clockwise direction by virtue of the friction imparted to finger stop 6 by friction washer 22 and the finger stop 6 will ultimately limit the rotation of finger wheel 23 when the users finger contacts finger stop 6 since the primary arm portion 33 will be urged into contact with side 35 of projection 5. The secondary stop will also come into play here since secondary arm portion 36 will also come into contact with side 37 of projection 4 when the finger stop 6 has been rotated to its full clockwise direction. Should the user attempt to rotate the finger wheel 23 an additional amount by attempting to lift finger stop 6 and hence move the primary arm portion 33 over the top edge of projection 5 adjacent to side 35, this further clockwise rotation will be prevented by the intersection of secondary arm portion 36 against side 37 projection 4. Since secondary arm 36 is located across the pivot point of the dials center, when the finger stop 6 is lifted in an attempt to ride up over the top of projection 5 this merely forces secondary arm portion 36 down to insure that it will not ride over the top edge of projection 4 adjacent to side 37. Hence any attempt to override the finger stop in the clockwise direction will be made even more difficult by this pivoting action which means that secondary arm portion 36 will be securely stopped by side 37. In a similar fashion, if the user attempts to lift finger stop 6 over the projection 4 in the counter clockwise direction, the pivoting of finger stop 6 will merely place secondary arm portion 36 further down and securely against side 38 of projection 5.

Hence it will be appreciated that by incorporating a second arm portion into finger stop 6, it is virtually impossible for the user to override the stopping projections of the dial in either the clockwise or counter clockwise direction without virtually destroying the dial itself.

FIG. 2 is a top plan view of the dial in the assembled position and illustrates the relative locations of the various parts. As shown in FIG. 2, friction washer 22 and the dial components thereabove have been removed so that the relationship between the finger stop 6,

projections

4 and 5 with their

sides

34, 37 and 35, 38 respectively is clearly illustrated. Main spring 11 has been al lowed to rotate the assembly to its normal rest or most counter-clockwise positon.

What is claimed is:

1. In a rotary dial for a telephone, wherein said dial includes a mounting plate having a pair of projections extending upward therefrom, and a finger wheel supported above said mounting plate for selective rotation, the improvement comprising a movable finger stop cooperable with said finger wheel for limiting the rotation of said finger wheel, said finger stop having a primary arm portion extending between first spaced apart sides of said projections and into the area encompassed by said finger wheel and a secondary arm portion extending between second spaced apart sides of said projections, whereby said first and second sides of said projections in cooperation with said primary and secondary arm portions respectively prevent said finger stop and hence said finger wheel from being rotated in excess of a predetermined amount.

2. The improved rotary dial as claimed in claim 1 wherein said primary and secondary arm portions lie in substantially the same plane.

3. The improved rotary dial as claimed in claim 1 wherein the minimum angle subtended between said primary and secondary arm portions is equal to or greater than 4. The improved rotary dial as claimed in claim 1 wherein said projections are elongated, and curved with respect to the axis of rotation of said finger wheel.

Claims

3. The improved rotary dial as claimed in claim 1 wherein the minimum angle subtended between said primary and secondary arm portions is equal to or greater than 90*.

4. The improved rotary dial as claimed in claim 1 wherein said projections are elongated, and curved with respect to the axis of rotation of said finger wheel.