US2090347A - Switch mechanism - Google Patents

Description

Aug. 17, 1937. A. M. DRAVING Er A1.

SWITCH MEGHANISM Original Filed Feb. 27, 1931 3 Sheets-Sheet 1 Agg. 17, 1937. A. M. DRAVING ET AL 2,090,347

SWITCH MECHANISM y 'original Filed Feb. gv, 1931 5 sheets-sheet 2 llll Aug. 17, 1937. A. M. DRM/1N@ ET AL 2,090,347

SWITCH MECHANISM Original Filed Feb. 27,f 1931 3 Sheets-Sheet 3 11 J5 i 70 *|17* JOS Il wax au l J 1l @a fa/@@5116 Bral/mg, 97 WZZz'amf/aazfga/IZ Patented Aug. 17, 1937 SWITCH MECHANISM Arthur M. Draving and William Irwin Ingham,

Philadelphia, Pa., asslgnors, by mesne assignments, to Chicago Telephone Supply Company, Elkhart, Ind., a corporation of Indiana Original application February Z7, 1931, Serial No.

518,836. Divided and this application February 4, 1935, Serial No. 4,807

3 Claims.

Our invention relates to electrical switches, either separately or in combination with potentiometers, volume controls, tone controls or resistances, the present application being a division of our copending application, Serial No. 518,836, entitled Electric switch and the like, tiled February 2'7, 1931.A

A purpose of our invention is to throw a switch by means of a tripping lever, preferably pivoted on the switch blade pivot, and to hold the switch blade in open or closed position by pressure from the movable end of the switch blade against the tripping lever in one of its limiting positions.

A further purpose is to provide an extension from a tripping lever, so that the switch may be thrown by engaging the extension.

A further purpose is to shape a tripping lever extension so that a projection moving over a predetermined path can engage the extension in one position, and, after throwing the switch, move free of the extension.

A further purpose is to limit the movement of a tripping lever and of its switch blade by stops, preferably using a single stop to engage the tripping lever in both of its extreme positions and to engage the switch blade in open position.

A further purpose is to mount a switch to be operated by a potentiometer, volume control, tone control or resistance dial within the control or other casing, and to throw the switch by a projection from the movable contact of the device, preferably insulating the projection from the contact.

A further purpose is to place within the casing of a potentiometer, volume control, tone control or other variable resistance, a switch operated by the movable contact, and to open and close the switch in a plane parallel to the plane of movement of the contact.

A further purpose is to trip a full stroke switch by one portion of the movement of a projection from a resistance-varying contact, desirably having the projection move free of the tripping mechanism in other positions.

A further purpose is to locate a. switch within the annular space inside a resistance coil and to operate the switch by turning the dial by which the resistance is varied.

Further purposes will appear in the specication and in the claims.

In the drawings we illustrate a few only of the numerous variations in which our invention might be embodied, choosing the forms shown from the standpoints of ease in construction,

(Cl. 20o-67) satisfactory operation and convenient illustration of the principles involved.

Figure l is a rear elevation of a switch embodying our invention. Y

Figure 2 is a section taken upon the line 2 2 of Figure 1.

Figure 3 is a detached perspective view of the principal parts of the switch of Figures l and 2.

Figure 4 is a perspective view of a somewhat different form of `our invention, in which the switch is located in the same casing as a potentiometer, volume control or tone control and is thrown by moving the dial.

Figure 5 is a section of the form of Figure 4, taken upon the line 5 5 of Figure 6.

Figure 6 is a section upon the line 6 6 of Figure 5.

Figure 7 is a section corresponding to Figure 6, but showing the switch in its opposite position.

Figure 8 is a section upon the line 8 8 of Figure 5.

Figure 9 is a fragmentary section upon the line 9 9 of Figure 8.

Figure 10 shows a variation in a section taken upon the line I0 l0 of Figure 11.

Figure l1 is a section of Figure l0 upon the line H l I.

Figure l2 is a View corresponding to Figure 1l, showing the switch in its closed position and omitting some of the contacts extending beyond the casing.

Figure 13 is a section upon the line |3 I3 of Figure l0.

Figure 14 is a. section of Figure 1l upon the line I4 |4.

In the drawings like numerals refer to like parts.

Numerous switches upon the market will operate by motion transmitted through turning a shaft, but relatively few switches may be thrown by substantially translatory movement of a switch operating projection, and of these, even fewer embody the full stroke feature.

In switches intended for opening and closing electric 1ighting circuits, radio circuits and the like, provided suitable electrical and mechanical characteristics are present, cheapness is the prime essential. The elimination of a single part or the change of a part so that it may be produced by a cheaper process, may make it possible to sell a switch which could not otherwise be placed upon the market.

We have invented a switch which meets the electrical and mechanical demands exceptionally well, and at the same time is extremely simple in construction. Aside from the switch blade and its pivot, only three parts are required in our preferred construction to perform both the tripping and full stroke functions. Oi these, one is a 5 spring and the others are extremely simplestampings.

Essentially this embodiment of our invention involves the use of a tripping lever to throw the switch blade through a toggle of which the tripping lever forms one element.

In the drawings we illustrate our switch separately and also embodied in two slightly variant forms of volume control. We will rst describe the construction of the switch proper, as seen in l5 Figures 1, 2, 3, 5, 6, 7, 9, 11,12, and 14.

The switch contacts comprise a stud 2|) and a spring strip 2|, which are connected together by a switch blade 22 when the switch is in closed position as seen in Figures 7 and 12. The switch 20 blade 22 is pivoted at 23, and moves to open position as shown in Figures 6 and 1l.

On a pivot line within the edge of the switch blade and preferably on the switch blade pivot 23 as shown, we place a tripping lever 24, which is '-5 free to turn with respect to the switch blade 22.

One end of the tripping lever 24 is notched at 25 to engage a cooperating notch 26 in a plunger 21.

A recess 28 in the plunger 21 permits the 30 plunger to fit rmly into the tripping lever `notch 25 without being forced therefrom by the opposite walls of the notch.

The plunger 21 is reduced in width at 29, forming shoulders 38 against which a spring 3| sur- 35 rounding the reduced portion 29 of the plunger, is held. 'Ihe other end of the plunger passes through an opening 32 in atab 33 turned out perpendicularly from the movable end of the switch blade 22. The tab 33 holds the spring, while the 40 plunger is free to move through the tab.

The tripping lever 24 is notched at 34, opposite to the notch 25, for engagement of a trippingY projection 35. The edges 36 and 31 of the notch 34 are preferably not symmetrical, so that the 45 tripping projection may move out of the notch on one side.

A single stop 38 serves to limit the movement of the tripping lever 24 in both open and closed positions and of the switch blade 22 in open posi- 50 tion. When the switch is closed, the shoulder 39 of the tripping lever engages the stop 38 as seen in Figures 7 and 12. In open position of the switch, the portion 40 of the tripping lever engages the stop, and the portion 4| of the switch 55 blade 22 also engages the stop, but the engagements are upon different portions of the stop as seen in Figures 6 and 11, so that the resultant lateral pressure against the stop is not excessive.

The operation of the switch embodies the full- 60 stroke principle. Considering the switch in closed position as shown in Figures 7 and 12, the switch blade 2,2 is resiliently pressed against the switch contacts 20 and 2| by the spring 3|. The spring 3| acts at one end against the movable end 65 of the switch blade 22 and at the other end, through the plunger 21, against the tripping lever 24 and ultimately against the stop 38.

It willbe evident that the plunger 21 and the tripping lever 24 form a toggle, from which the 70 switch blade is resiliently pressed into closed position.

The switch is shown in open position in Figures 6 and 11.

To open the switch, the tripping lever 24 is 5 moved to its opposite limiting position in any suitable manner, as by contact of the tripping projection 35 against the edge 31 of the tripping lever notch 34. This swings the toggle to the other side of its neutral position, so that the tripping lever portion 40 engages the stop 38, and the plunger 21 swings about the walls of the opening 32 in the switch blade tab 33 as a pivot, while the walls of the notch 26 in the swinging end of the plunger 21 maintain their engagement with the walls of the notch 25 in the tripping lever 24.

Shifting of the position of the toggle compresses the spring 3|, so that as soon as the toggle passes its neutral position, the switch blade is snapped to open position under the action of the spring, simultaneously with or even before the arrival of the tripping lever against the stop. The switch blade 22 comes to rest when the portion 4| of the switch blade strikes the stop 38.

The details of the switch housing and of the means for operating the tripping projection are immaterial to the broad aspects of our invention. However, certain features of the housing and of the operation of the tripping projection cooperate very desirably with the switch of our invention, particularly because the plane of movement of the switch blade in opening and closing is the same as the plane of movement of the tripping projection, so that the switch assembly may be made very compact.

In Figures 1 to 3 we show our switch in a casing intended to hold the switch alone. The parts of the switch proper, as previously described, are mounted upon a base 42 of insulating material. The stu-d 20 passes through the insulation and is riveted to a contact 43 on the back. The switch spring contact 2| is secured by a rivet 44 to a contact 45. From both of the contacts, 43 and 45, ears 46 have been bent down and extended through the insulation to prevent turning of the contacts 43 and 45. An opening 41 in the spring contact 2| admits the end of an ear 46, to prevent the contact 2| from turning.

Openings 46 and notches 49 in the contacts 43 and 45 facilitate attachment of wires to the contacts. The stop 38 is the head of a rivet passing through the base 42. The switch blade pivot 23 is also desirably a rivet, on which a washer 58 is placed to provide a smooth bearing for the switch blade.

The switch is enclosed within a casing 5|, flanged outwardly at 52 to hold the insulating switch base and peened at 53 to prevent removal of the base.

'Ihe casing is adapted to be supported from a panel by tightening a nut upon a bushing 54 against a lock nut 55. The bushing is reduced in diameter at 56 where it passes through an opening in the casing 5|, and turned over at 51 to unite the bushing to the casing.

Through the interior of the bushing passes a spindle 58 which is coined at 59 at one end to receive an arm 60, desirably of insulating material, having a triangular opening 6|, and a stop 62 having an opening63. The arm 68 and the stop 62 are secured to the spindle by riveting the coined end 59. On the movable end of the arm 66 is secured a switch tripping projection 35 by riveting at 64 and by extending an ear 65 through the arm 60.

The stop 62 carries a segment 66, which moves between limiting positions in contact with one or the other of the clips 61 and 68 pressed up from the body of the casing. In the form of Figures 1 to 3, the spindle 58 performs no other furction than that of throwing the switch. so that by that name.

In designing radio panels it is highly desirable to have as few knobs and dials as possible. The initial movement of the variable resistance dial commonly carries the contact over an insulating strip before the resistance winding is reached, and therefore is not directly effective in changing the resistance. It had been proposed to connectV the variable resistance contact to a switch, desirably the main circuit switch of the set, so that the switch will be closed by this initial variable resistance dial movement, and, when turning the variable resistance dial back to its initial position, so that the switch will be opened.

-In this way the extra knob ordinarily necessary for control of a switch is eliminated. The connection in the past has been made from the variable resistance through a system of levers to a separate switch unit usually supported upon the back of the variable resistance casing.

By our invention we are able to mount the switch within the variable resistance casing proper, where the operating connection between the variable resistance contact and the switch may consist simply of a projection from the variable resistance contact. The operating projection is made to engage and throw the switch at one position of the contact and to travel free from the switch in the other positions.

In order to avoid possible short-circuiting of l the switch or the variable resistance, we insulate we intend the illustration of the variable resistance shown by us to be essentially diagrammatic, since our invention is applicable to any variable resistance having a moving contact maker, whether the moving body is the resistor or a contact sliding along the resistor.

In Figures 4 to 9. the casing 10, desirably made of metal, is formed in two parts, consisting oi.' a front 1I and a rear 12 joined by anging at 13 and peening at 14.

Within the front part 1i of the casing we show a resistance winding 15 upon a form 18 and annularly surrounding an insulating disc 11. To prevent contact between the resistance winding 15 and the casing, an insulating sheet 18 covers the inside of the front easing face. I

The movable contact of the variable resistance consists of a spring metal clip 19 supported by annular arms 80 from a central disc 8i secured upon the variable resistance spindle 58'. Cut from the central disc, a brush 82 wipes over the face of a disc 83 integral with a contact 84 extending through an insulating sheet 85 covering an opening 86 in the casing. I'he disc 83 has an ear 81 turned down and held in an opening 88 in the insulating disc 11. An ear 89 punched up from the casing front 1| also enters the opening 88. The ears assist in centering the respective parts.

Connection is made to the ends of the resistance winding 15 by contacts 80 and 9i bent into recesses 92 in the disc 11 and secured by screws 93. Where the winding is used as an ordinary rheostat, the contact 84 and one only of the contacts 90 and 9| will be employed, but where the winding is used as a potentiometer, the three contacts will all be used.

The construction of the bushing, spindle and stop mechanism is substantially the same as that shown in Figures 1 to 3, except in a few features as noted. The narrow portion 58 of the bushing extends through the insulating disc 11 and the contact disc 83 and is turned down at 51. A clip 61' is bent up from the contact disc 83 to engage the segment 56 of the stop 62 secured to the coined end of the spindle, and limit movement of the movable contact 19. The single clip 61 engages the stop in both limiting positions.

As seen in Figure 5, the spindle 58' extends through a panel 94 and carries a dial 95 which covers a nut 36 holding the variable resistance to the panel.

Thus far we have described what is essentially a conventional variable resistance. On the back casing portion 12 we mount a switch similar to that shown in Figures 1 to 3. Attachment of the switch base 42 to the casing is desirably made by rivets 91 as shown.

On the movable variable resistance contact 8| we secure in any suitable manner as by rivets 88, an insulating piece 98 to the outer end of which the tripping projection 35 is fastened. As an additional protection against failure of electrical insulation between the variable resistance and the switch, we secure an insulating partition |08 to the base of the tripping projection 35.

When the movable contact 19 is in its limiting position at the end of the resistance winding connected to the contact 90, as shown in Figure 8, the tripping projection 35, opposite to the movable contact 19, is in the position shown in Figure 6, with the switch open. 'I'he spindle 58', contact 19 and tripping projection 35 cannot travel further counter-clockwise (as seen from the iront) because of the spindle stop 62 and also because of the switch stop 38.

Movement of the spindle 58' clockwise is however possible, and the rst part of the clockwise l stroke is eiective to throw the switch from the open position as shown in Figure 6 to the closed switch position as shown in Figure 7. Further clockwise movement of the spindle 58 disengages the tripping projection tripping lever 24. 'Ihe tripping projection 35 is seen in Figure 7 just after leaving the slot 34.

Further clockwise travel of the spindle 58 carries the movable contact 19 over the variable resistance winding 15, varying the resistance connected between the respective contacts 90, 84, and 8i in the usual manner.

Reversal of the direction of turning of the spindle ilrst carries the movable contact 'I8 over the resistance winding 15, and nally causes the tripping projection 35 to engage the tripping lever 24 and open the switch.

Thus the initial and final ranges of movement of the variable resistance are employed to close and open a switch, which will ordinarily be the main circuit switch in a radio set.

A In Figures 10 to 14 we illustrate a somewhat different form of composite variable resistance and switch, in which the switch is located within as from the not a4 of the the annular space inside the variable resistance, thus minimizing the space requirement and permitting closer connection between the variable resistance spindle and the switch.

The variable resistance in this form is essentially the same as that illustrated in Figures 4-9 except for variations in detail. The casing is formed in two parts, of which the front portion 1|' is metallic and the rear portion 12' i0 is molded from suitable insulating material. The i'ront portion 1|' has been annularly flanged at |0| to fit within an annular depression |02 in the molded rear casing portion 12. At points |03 part of the outer edge of the metal casing 15 portion 1| has been cut away toallow the casing to clear projections |04 extending from the walls of the depression |02 and to permit the front casing portion 1|' to be held in position by turning it with respect to the rear casing portion The terminal 84' lies on the outside of the front casing portion 1 and extends through the terminal notch 842 in the rear casing portion, 12'. 'I'he notch 842 prevents turning of the front casing portion 1|' with respect to the rear portion 12', so that the terminal 84' must besprung out of the notch 842 before the front casing portion 1|' can be turned with` respect to the rear casing portion 12 to separate the casing portion. The

terminal 84' is united to the casing portion 1| by turning down the end 51 of the bushing 54. A projection 81, punched up from the front casing portion 1|', engages the movable stop 62 as .in the other forms. An ear |05, turned down from the terminal 84', passesthrough the opening in the front casing portion 1|' formed by punching out the projection 61, to assist in centering the terminal.

The method of attachment of the movable stop 40 62 and of the movable contact 19 to the spindle 58 is identical with that used in the other forms. In Figure 13 we illustrate notches |06 in the movable contact disc to assist in connecting together a plurality of contacts for operation by a single spindle, where that is desired. 1

The resistance Winding- 15 and the form 16 diier somewhat from that shown in Figures 4 to 9, as the winding has been made wider to fit into a depression |01 formed by an annular ridge |08 in the base of the molded casing 12'.\ Connection to the ends of the resistance winding is provided by contacts 90 and 9|' secured to the winding by screws 93', extending through the casing.

The switch has been mounted on abase 42 secured to the casing by rivets |09, and rested on the inner edge of the ridge |08. Leads ||0 extend from the switch contacts 43 and 45' to contacts and ||2 secured to the rear of the 00 casing 10' by rivets ||3.

It will of course be evident that the space between the switch base 42 and the rear of the casing portion 12' may be used as desired, for example to hold a fixed resistor.

The structure just described is particularly desirable because space radially within variable resistance windings which otherwise would not be advantageously used, is employed to hold the switch. This is made possible because the switch opens and closes in a plane parallel to the plane of movement of the movable contact of the variable resistance.

It will be evident, that, besides providing a distinctly useful switch, we provide a switch which is particularly well suited for embodiment in a variable resistance, because it may be thrown by a projection from the movable contact during a tions and modicatlons to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benets of our invention without copying the structure shown, and we, therefore, claim all such in so far as they fall within the reaonable spirit and scope of our invention.

Having thus described our invention, what we claim as new and desire to secure by Lettersl Patent is:-

1. In a switch assembly, a cylindrical metallic housing, one end wall of said housing being formed of a flat sheet of non-conducting material, a pair of switch contacts carried by said end wall, a pivotlcarried by the end wail spaced from the cylindrical housing wall, a switch arm supported by the pivot adjacent the end wall and movable parallel thereto, a switch actuating member carried by the pivot, spring toggle means connecting the switch arm and actuating member, an extension on said actuating member toward the cylindrical housing Wall and away from the switch arm, and means for engaging said extension to actuate the switch to move the switch arm into and out of bridging engagement with said contacts.

2. In a switch assembly, a cylindrical metallic housing, one end wall of said housing being formed of a iiat sheet of non-conducting material, a pair of switch contacts carried by said end wall, a pivot carried by the end wall spaced from the cylindrical housing wall, a switch arm supported by the pivot adjacent the end wall and movable parallel thereto, a switch actuating member carried by the pivot, spring toggle means connecting the switch arm and actuating member, a forked extension on said actuating member toward the cylindrical housing wall and away from the switch arm, and means for transiently engaging said extension to actuate the switch to move the switch arm into and out of bridging engagement withv said contacts.

3'. In a switch assembly, a cylindrical metallic housing, one end wall of said housing being formed of a ilat sheet of non-conducting material, a switch contact carried by said end wall, a pivot carried by the end wall spaced from the cylindrical housing wall, a switch armsupported by the pivot, a switch actuating member carried by the pivot, spring toggle means connecting the

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