US2290124A - Safety switch - Google Patents

Description

Ju1y14, 1942;

F. COLBY SAFETY SWITCH Filed Jan. 20, 1942 2 Sheets-Sheet l July 14, 1942. F. coLBY 2,290,124

SAFETY SWITCH Filed Jan. 20, 1942 2 Sheets-Sheet 2 Patented July 14, 1942 UNITED STATES PATENT OFFICE 7 Claims.

ThisI invention relates to a safety switch for use in electrical circuits, such as are employed in lighting, household appliances, and particularly conveyances, such as motor boats, automobiles and the like.

The safety switch according to this invention is an improvement over that disclosed in my Patent No. 2,208,179, July 16, 1940.

The improved switch herein disclosed, in common with that of my patent, embodies a fluid circuit interrupter of such construction as to be effective to interrupt an electrical circuit by either manual or automatic operation.

The general switch construction according to my prior patent embodies a casing enclosing a vertically elongated chamber, opposed arcuate electrodes embedded in the Walls of the casing and having spaced plane contact surfaces close to opposite sides of a plane including the axis of the casing, a fluid conducting medium in the Y chamber, and a vertically movable piston within the chamber for alternately forcing the fluid into and out of contact with the electrodes for making and breaking the circuit respectively.

The particular arcuate form of the electrodes automatically interrupted only upon tipping of the switch casing one way or the other, substantially in a single plane at right angles to the planes of the opposed electrode contact surfaces.

In other words, the switch in accordance with my patented construction when used in automobiles for instance, would be effective for automatic interruption of the circuit only upon overturning of the automobile on one side or the other thereof for the reason that the electrode contact surfaces were necessarily maintained in planes parallel to the medial longitudinal axis of the automobile.

A primary object of this invention is therefore to provide a more flexible and effective control for a switch as embodied in my patent whereby the circuit may be manually or automatically interrupted upon overturning of the normally vertically disposed switch casing at any angle circumferentially oi the axis thereof with a further cooperating manual control for closing of the circuit when it is broken in any overturned position of the casing.

A further object of the invention is the provision of a switch of the above noted character which is relatively simple, compact and rugged in construction, and which will retain its operating eiiiciency for an indefinite period of time.

Other objects and advantages of the invention will appear as the description of the appended drawings proceeds.

I desire to have it understood however, that I do not intend to limit myself to the specific details shown or described, but that I intend to include as part of my invention, all such obvious changes and modifications as fairly fall within the scope of the claims.

In the drawings, forming a part of the specication,

Fig. l is a vertical sectional View through a switch in accordance with one embodiment of the invention.

Fig. 2 is a transverse sectional View of the switch taken substantially in the plane of line 2-2 of Fig, 1.

Fig. 3 is a View similar to Fig. 2, but showing the switch as having been rotated through an angle of 90.

Fig. 4 is a View similar to Fig. 1, disclosing a modified embodiment of the invention.

Fig. 5 is a transverse sectional View of the switch of Fig. 4 and taken substantially in the plane of line 5-5 thereof.

Fig. 6 is a fragmental vertical sectional view disclosing a modified form of swivel mounting for the switch casing.

Fig. 7 is a ragmental elevational view disclosing a modified form of piston operating and switch casing rotating means.

Fig. 8 is a top plan View of the structure illustrated in Fig. '7.

Fig. 9 is a view partly in elevation and partly in vertical section disclosing a further modified form of piston operating and switch casing swiveling means.

Fig. l0 is an elevational View of the switch of Fig, 9 as observed from the right thereof.

Fig. 11 is a view partly in elevation and partly in vertical section disclosing a further modified form of the invention.

Fig. l2 is a horizontal sectional View as observed in the plane of line l2-I2 in Fig. 11.

Fig. 13 is a reduced fragmental view partly in elevation and partly in vertical section disclosing a still further form of the invention.

Referring to the drawings in detail, and first to Figs. 1, 2 and 3 thereof, there is shown a switch structure similar to that of Fig. 1 of my patent above referred to and which embodies a casing Il) of insulating material and in which are embedded two arcuate shaped electrodes II and I2. The electrodes II and I2 have terminals I3 and I4, respectively which may be connected in a lighting or ignition circuit including the battery and ground of an automobile. In this case however, the terminals should have flexible leads for reasons later apparent.

The casing is provided with diametrically spaced vertical channels I5 (Fig. 2) which are preferably of a depth equal to the diametrical width of the electrodes and which are of a width equal to the spacing between these electrodes and such channels may extend through the length of upper and lower portions of the closed chamber formed in the casing I0.

A piston It is reciprocably mounted in the casing and is normally disposed completely, immersed in a current conducting fluid Ita, and such piston is preferably formed with its top and bottom ends conoid or rounded, as shown at Ib.

Through this formation of piston a retentive reservoir for a portion of the conducting iluid is always provided below the piston irrespective of how the switch is turned in vertical operating position of the casing. This reservoir cooperates with the channels I 5 to maintain a supply of conducting i'luid between the end of the electrodes II and I2 under operating conditions wherein the axis of the casing is deflected from the vertical.

As indicated in Fig. 1, the piston is normally in circuit closing position with the volume of iluid within the space immediately above the piston and between the opposed faces of the electrodes II and I2 so as to bridge the gap between the ends of said spaced electrodes and thereby com- L plete the circuit between the terminals I3 and I4. If the .piston is raised from this normal position to occupy the upper end of the vertically disposed casing, the volume of fluid is such that it will assume a level slightly below the electrodes and k,

thus the circuit may be interrupted at will in this manner. For this purpose the piston I6 is provided with a cylindrical rod member I1 having a ball-like enlargement I8 at its upper end and handle portions I9, extending outwardly from the ball-like enlargement.

The chamber of the casing is closed at its upper end by a plate 2li and a superposed plate 2I which are rigidly held together by bolts 22 which extend into the walls 0f the casing, the plate 2i) being provided with a suitable packing gland 23 for the cylindrical piston rod I'!.

As it is desired to retain the piston at various elevations within the chamber of the casing a pair of spring steel strips 24 are each provided with cooperating corrugations as at 25, to provide vertically spaced and horizontally opposed ball receiving sockets for holding ball I8 in desired vertical positions.

As shown these strips 24 are engaged and secured to the plate 2| by the bolts 22 which maintain the same in horizontally spaced apart positions a distance substantially equal to the diameter of handle I9, for reasons later to appear.

A base member 21 receives or is otherwise formed rigid with the lower end 0f the casing It). As shown in Fig. l the cup-like base member, is maintained rigid with the casing by means of a set screw 28. In either case, however, the base member 2l' is pivotally or swivelly mounted on a support by means of a bolt 29 which extends through the base 3U co-aXial with piston rod member I1. A bowed leaf spring 3lv has its ends retained and guided by pins 32 depending from the support 3Q, and a nut and washer 33, 34 are received by the bolt 29 for tensioning the spring to provide the desired frictional contact between base member 2'I and support 3b for normally holding the casing in any pre-determined position, angularly about its axis. The leaf spring 3| may be threaded to receive bolt 29 and washer 34 and nut 33 would serve as a locking device in maintaining a constant tension.

As is fully disclosed in my aforesaid patent, the conducting fluid Ia normally bridges the gap between the electrodes II and I2 and thereby completes the circuit between the terminals I3 and I4, when the piston is in its normally lowered position, also that the'circuit will be automatically broken should the casing tilt or tip over either to the right or left of (Fig. 1), i. el., substantially in the plane of the terminals I 3 and I4 or at right angles to the planes of the contacts of the electrodes. This is due to the fact that the conducting uid will then rest within the opposite end of the chamber of the casing (or in the hollow of but one of the electrodes) and will thus not reach a level in the chamber to bridge the gap between the electrodes. In this latter tilted position however, the circuit is capable of being manually closed by raising the level of the fluid in the chamber and into electrode bridging position by pulling the piston I6 through the body of conducting fluid to the other end of the casing chamber by means of the rod I'I and handle I9. It will thus be clearly observed that upon tilting automatic breaking of the circuit will occur only upon overturning of the casing I0 substantially in the plane of the axis of the terminals I3 and I4 whereby the opposed Dlane contact surfaces of the electrodes will be in horizontal planes or in equally spaced relation to the fluid level in such overturned position. It is to be particularly noted that the circuit may be closed after having been broken in the manner above described by rotation of the electrodes with respect to the base.

Should the casing I0 overturn in a plane at right angles to that indicated in Fig. 2 so that the circuit would not be automatically broken, I have now provided means whereby the electro-des may be shifted to the position of Fig. 3 with the terminals I3 and I4, substantially in the plane of such overturning movement. This variable positioning of the electrodes for elfective automatic breaking of the circuit upon overturning of the casing I 0, as occasioned by a like movement of an automobile on which the switch may advantageously be used, is readily effected by the swivel mounting of the casing and the spacing of the strips 24 as above described. The vertical guide slot provided by the spaced portions of the corrugated steel strips 24 cooperates with the handle I9, so that the casing may be readily rotated or swivelled according to the direction in which the casing may be overturned.

It is to be particularly noted that the two laterally extending portions of the handle I9 are always at right angles to the terminals I3 and I4, and thus may serve an accurate gauge and guide to the operator since it needs only be turned at right angles to the direction of overturning movement of the casing for effectively breaking of the circuit. II" desired, however, the parts may be so arranged that the handle I9 may be positioned in the plane of the terminals |3 and i4, in which instance the casing only .be turned in the direction of overturning movement of the casing.

By the arrangement above described, the handle I9 not only functions to adjust and position the piston I6 in circuit closing and breaking positions within the chamber of the casing but it also acts to rotate the casing about its axis on the bolt 29, in either direction as indicated by the arrows in Fig. 2, and to any angular position about its axis as indicated by dot-and-dash lines in Fig. .2.

In Figs. 4 and 5 is illustrated a modified embodiment of the invention wherein the piston and pivotal movement of the casing are effected by separate means. This arrangement may be found satisfactory in certain instances but would not be as eflicient as the structure of Fig. 1, particularly upon sudden overturning as occasioned by an automobile.

In Fig. 4, a switch similar to that of Fig. 3 in my patent is illustrated and Which embodies a casing Mia enclosing an inner chamber having a tapered inner wall 36. 38, of this form have complementary tapered portions as ati-I9 and 40, portion 40 being contiguous with wall surface 39. The upper wall portion of this casing has a cylindrical restricted portion 49a adapted to receive the elongated cylindrical portion 4| of the closure member 42. The inner surface of the portion 4| is shown inwardly tapered as at 43 and is contiguous with the tapered portions 39 of the electrodes 31 and 33.

Closure member 42 has a central opening 44 through which an operating rod 45 passes, the rod carrying a piston 46. Above the opening 44 there is provided a packing gland 41 and formed integral with the closure member there is shown an extension 48 in which is threaded a closure plug 49.

The plug 49 is counter bored and this bore tightly receives the end of the flexible tube U through which rod 45 extends and which operates on the principle of a Bowden wire.

The piston 46 has upper and lower tapered portions 5| and 52 corresponding to the upper and lower tapered walls 43 and 36 of the chamber within the casing.

The form of switch operates substantially in the same manner as that of Fig. 1 except that the piston may be adjusted to any pre-determined vertical position. This Bowden wire type is particularly adapted for use in remote control.

Provision is made for rotation or swivelling of casing |922 for the purpose above set forth and is accomplished by means of a flat base member 54 secured as by screws 55 to the bottom of casing ma. This base member is pivotally supported on a bolt 59 co-axial with the casing, the bolt extending through a support 51 and having a nut and washer 59 and 59 for compressing a bowed leaf spring 69 for maintaining frictional contact between the base member 54 and support 51 for reasons above set forth in connection with Figs. 1 to 3.

The base member 54 is provided with a boss 6| having a transverse bore to receive one end of a Bowden wire 62 extending through a flexible member 63 and which is retained in the boss bore by means of a set bolt 64. With this modied arrangement the casing I5ab may readily be swivelled on its axis by the wire 62 and the plunger may be vertically controllable by means The electrodes 31 and.

of the rod 45 in any rotary position of the casing.

A modied .arrangement of switch casing Il!b is rotatably supported on a dish-form base 66 by means of a bolt 61 retained in the casing by means of a laterally disposed bolt 68 having a comparatively large head 69. The bolt 61 extends through a bowed leaf spring 19 and has its head 1| engaging said spring and rotatable relative thereto. The head 69 is bored as at 12 to receive a Bowden Wire to be retained in position by means of a set bolt 13.

In Figs. 1 and 8 is disclosed a modified arrangement of piston operating and casing rotating means. As shown in these figures the switch casing I9c is provided with a single corrugated spring steel strip 15 deiining a vertical loop member similar to that shown in Fig. 1 and having opposed legs 16 secured to the casing by bolts 11. The piston rod 18 in this arrangement is provided with a cylindrical member 19 engageable in opposed concave portions of the spring strip loop and a further rod 89 projects upwardly from member 19, through the upper end of the loop and is provided with an operating handle 8|. This form is believed to be most convenient for unit operation particularly from the seat of a vehicle, since the rod may project up through the oor board and on which rod the elongated cylindrical handle 8| extends in the plane of the axis of the electrode terminals. A ready means of rotatively setting the casing is thereby provided for efficient circuit breaking irrespective of the direction of tilting movement of the casing in the event of overturn of the vehicle.

In Figs. 9 and 10 is disclosed a further modified embodiment of means for both actuating the piston and imparting rotation to the switch casing about its axis. The switch casing IE5d is here shown embraced by a sleeve 92 having a slot in the side wall thereof and which. slot includes a vertical portion 83 having three lateral extensions 84 for selectively receiving a headed pin 35 projecting from the exterior wall of casing |911. The upper end of sleeve 92 is dome shaped as at B6 and has a ball 61 suitably secured thereto. A piston rod 89 carrying piston 69 at its lower end, is rigidly secured in an aperture in the ball 81 by means of a set screw S9 so as to be manually operable thereby. 'Ihe sleeve is recessed at 9| to clear the terminals |3, I4 and the remainder of the structure is the same as that of Fig. and is indexed accordingly, With this arrangement, the piston may be readily moved by first slightly turning the sleeve to bring the pin 35 into the vertical portion. 83 of the slot, the extensions 94 serving to normally retain the sleeve piston in selected vertical positions, rotation of the casing may then be accomplished by engagement of the pin with the ends of extensions 94 and remote side of slot portion 83.

While the foregoing described embodiments of the invention each provide manual controls for the rotation or swivelling of the switch casing which will prove satisfactory in many uses of the switches. an automatic means for rotating the casing to proper position for circuit breaking is preferable in such uses of the switch as in automotive vehicles, motor boats and the like, wherein the overturning is sudden and there is usually neither time nor any accurate means provided for ascertaining the correct angular position of the casing for manually effecting proper interruption of the circuit.

For such uses therefore I have provided in Figs. 11 and 12, an embodiment of the invention wherein the switch casing I6@ is automatically rotated for automatic breaking of the circuit regardless of the direction of overturning of the casing and which embodiment is particularly effective for the uses stated. For this purpose a base member S3 is rigidly secured to the lower end of the casing we, as by means of a set screw 94, and the base member is so formed as to provide an upper ball bearing race and a companion lower race S secured to a support Sii, as by bolts 91. Bearing balls 93 are retained between the races by means of a pivot bolt 99 having its upper end rigidly secured to the member 93 and thence extending through the member, and a bearing sleeve 18S and terminating below the support 9S.

An arm lill is secured to the bolt 99 by nut H12 and associated washers carried by the bolt for rotation therewith. A weight 103 is supported by the free end of the arm and this arm is normally held in the plane of the electrode terminals i3, Ell by relatively inverted V-shaped spring lofidependingr from the support Si@ at each side of bolt 9 for yieldably engaging arm ll and holding the casing in the proper normal position which is as shown in Fig. 11, or with the arm engaging the other spring IM.

The casing Ide is preferably provided with piston lifting means similar to that of Fig. '7 including a corrugated strip H35 and handle 185. This form as well as that of Fig. 1 also provides for manual rotation of the casing, whereby it may readily be set into normal operating position.

Since the arm Ill! is normally in the plane of terminals i3, le such terminals will be automatically rotated into the plane of overturning movement of the casing by the weight |133 which obviously will fall into such plane by action of gravity.

A similar arrangement is shown in Fig. 13 modified by the substitution of an arm |08 for the arm Il. The arm Hi8 is shown pivotally connected at one end thereof to a lug |69 extending from the base member 93 and a bowed spring HG is secured to the lug m9 and bears on the arm m3 to yieldably urge it downward toward the support 96.

The support e6 is provided with a pair of oppositely disposed relatively shallow spherical sockets Il! for selectively receiving a ball H2 rotatably supported on the arm I 38, in either normal operating position of the switch casing.

While I have shown different forms of cooperating electrodes and pistons as in Figs. 1 and 4, it is to be noted that they may be reversed and that either form or even other forms as shown in my patent may be used in combination with the casing swivelling structures herein disclosed.

Having thus described the invention in accordance with certain preferred embodiments, what is claimed is:

l. In a safety switch, a cylindrical casing having walls defining a closed chamber therein, means pivotally supporting said casing in normally vertical position, electrodes mounted in spaced relation in said walls intermediate the opposite ends of said chamber and providing a gap therebetween substantially in the vertical axial plane of the casing, means associated with said casing and its pivotal mounting for rotating said casing on its axis to position the plane of .the electrode gap at substantially right angles to any direction of tilting movement of said casing toward a horizontal position upon overturning thereof, conducting fluid within said chamber of a volume to normally bridge said gap when the casing is in its normally ver-tical position and to recede into said chamber out of bridging relation' with said gap upon rotation and tilting of said casing in any of said directions, and manually operable means moVably mounted within said chamber and coacting with said fluid therein to cause the same to again bridge said gap while said casing is tilted in any overturned position.

2. A safety switch according to claim 1 wherein said means for pivotally supporting the casingcomprises a base member rigidly connected With the lower end of the casing, a pivot bolt coaxial with the casing extending through said base member and a support therefor, and yieldable means holding said base member in frictional engagement with said support while permitting relative rotation therebetween.

3. A safety switch according to claim 1 wherein said means for pivotally supporting the casing comprises a base having a casing support mounted thereon, a headed pivot bolt coaxial with the casing extending vertically through said base and into said casing, a leaf spring disposed between said base and the head of said bolt for urging said casing into frictional con-tact with said base, and means anchoring said casing to said casing support to hold the casing in axial position upon the base.

4. A safety switch according to claim 1 wherein said manually movable means in the chamber comprises a piston having an operating rod extending 4through the upper end of the casing, and wherein said means for rotating the casing comprises a member rigid with the rod and means supported by the casing and engageable by the member for rotation of the casing upon rotation of the rod.

5. A safety switch according to claim 1 wherein said manually movable means in the chamber comprises a piston having an operating rod extending through the upper end of the casing, a pair of flexible spaced corrugated strip portions secured to the upper end of the casing, a member rigid with the rod and having rounded sides engageable within opposed recesses of the corrugations to maintain the rod in vertical adjusted position, and wherein said means for rotating the casing comprises a rod operating handle extending diametrically of the member and projecting between adjacent edges of the strips to effect rotation of the casing upon movement of the handle around the axis of said rod.

6. A safety switch according to claim 1 wherein said manually movable means in the chamber comprises a piston having an operating rod projecting through and above the top of the casing, a member secured to the upper end of the rod for operating same and means for selectively retaining the piston in different positions in the chamber and for effecting said rotation of the cylinder comprising a sleeve embracing the cylinder and secured to said ball, a headed pin projecting from the outer wall of the cylinder, and a slot in the sleeve including a vertical portion and lateral portions from one side thereof, the vertical portion permitting movement of the piston in the chamber, the lateral portions selectively receiving the pin to hold the piston in any selected position, and the ends of the lateral portions and opposed side of the ver-tical portion being engageable with the pin upon rotation of the sleeve to impart rotation to the cylinder.

and below said support, an elongated arm having one end thereof secured to said base member and extending normal to said plane of the gap, a weight on the other end of said arm, and friction means associated with said base and support for retarding free rotation of said arm in normal vertical operating position of said casing.

FRED COLBY.

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