US2349871A - Switch and method of controlling circuits - Google Patents

Description

ay 36, 1944 H. L.. LAMBERT 2,34%,871

SWITCH AND METHOD OF CONTROLLING CIRCUITS Filed Sept. 22, 1939 @VENTQR 1922773 Z. Lawzefi B/ CVI/Wfi m ATTORNEYS Patented May 30, g 1944 SWITCH AND METHOD OF CONT'BOILING CIRCUITS Barry L. Lambert, Enfield, N. Y., assignor to Allen Wales Adding Machine Corporation, Ithaca,

Application September 22, 1939, Serial No. 296,124

26 Claims.

repeated openings or the circuit of the motor,

and when mercury was employed the governors could only be operated successfully when disposed in a single position. Such devices in use are frequently mounted by the users in different inclined or angular positions in violation of instructions, and this sometimes ailects the speed at which the switch devices will open, and in some constructions the governors will not even workat all in more than a single limited position. When the position of the governor is changed, it sometimes happens that the centrifugal force required to break or open the circuit is greater than when the device is operated in other positions, and this is also objectionable.

An object of the invention is to provide an improved method of controlling an electric circuit which will be relatively simple, and which will require a minimum of apparatus and servicing attention.

Another object of this invention is to provide an improved automatic electrical switch, controlled by the speed of rotation of a rotating element,,and which switch will be simple, eflicient and inexpensive.

Another object of the invention is to provide an improved switch of the liquid or mercury type, the operation of which will be independent of the action of gravity, which will alter the circuit only by forces greater than gravity, and which may be operated equally well in all positions.

Another object of this invention is to provide an improved switch device for controlling the speed of an electric motor which will not be dependent upon or operated by the action of gravity in limiting the speed of the motor, and with which the circuit will not be broken by gravity in any position of the device, which will be relatively simple, compact, durable and inexpensive, and which will require a minimum of maintenance and attention in service.

Another object of the invention is to provide an improved speed governor switch which will run equally well in any position, which will not require the use of pivoted weights, which will operate to control the speed only in response to centrifugal forces and in which the influence of gravity in affecting the opening of a circuit will be negligible, with which the circuit may be opened only by a force greater than gravity, with which there will be no burning of contacts, which will operate for long periods of time without disintegration, damage or injury to the circuit controlling parts, which will require a minimum of servicing in use, and with which the speed at which the circuit will be opened may be varied and adjusted in a very simple and practical manner.

Other objects and advantages will be apparent from the following description of two embodiments of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawing:

Fig. 1 is a longitudinal, sectional elevation through a speed governor of an electric motor, which has been constructed in accordance with this invention and in which the parts are shown as in the positions occupied during use, that is, during rotation;

Fig. 2 is a transverse, sectional elevation of the same, the section being taken approximately along the line 2-2 of Fig. 1;

Fig. 3 is a smaller, transverse, sectional elevation through the same, the section being taken approximately along the line 3--3 of Fig. 1 and illustrating the position of the mercury globule during rotation at a speed below that at which the device is set to open the circuit of the motor;

Fig. 4 is a similar sectional elevation along the line 3-3 of Fig. 1 but showing the position and shape of the globule of mercury at the time the circuit is opened at a predetermined. speed; and

Fig. 5 is a transverse sectional elevation similar to Fig. 2 but showing a modification of the mounting of the contact mechanism on the rotatable member.

In the embodiment of the invention illustrated in Figs. 1 to 4, the switch device is illustrated as employed for controlling the speed of an electric motor l0 having its drive shaft ll extending from one end thereof and directly mounting the governor. This motor It! may be of any suitable type, whether operated by either direct or alternating current, or it may be a universal motor operable equally well on either type of current. The current for the motor is supplied from line wires L and L and controlled by any suitable this recess.

master controlling switch (not shown) in the usual manner. The line 'wire L is broken, however one portion thereof at the break being connected to a brush l2, and the other portion thereof at the breakbeing connected to a brush i3.

I suitable type is mounted on the end of the shaft II, and this member l4 has a tubular boss l5 which fits over the end of the shaft II and is secured thereto'in any suitable manner such as by a set screw IS. The member has two-end"""' faces which are transverse to the axis offrotation of the shaft H. Upon one of [these end faces, such as the face towards the motor, a pair of collecting rings l1 and I8 are secured. These rings are of metal, of difierent diameters, and concentric with the axis of rotation of the shaft I I. They may be mounted on or anchored to the face of the member l4 in any suitable manner (not shown). The brushes l2 and I3 bear upon the exposed end faces of the rings I! and 18 so as to establish circuit connections thereto from the sections of the line wire L during the rotation of the motor. It will be understood that the brushes l2 and I3 may 'be of any suitable typ but in the particular illustrated example,- th brushes l2 and i3 ";are slidably received in the open end of tubular bushings l9 which extend through a bar 20 of insulating material. This bar is carried by studs 2| projecting from the 21 so as to forma tight fit therewith and thus form a tubular extension from the support 24. The free end of the tube 28 is closed by a plug or closure 29 of suitable insulating material which preferably telescopes slightly within the end of the tube and also abuts against the outer end of the tube. A metal rod or bolt 30 has its head 3| countersunk in the disk or support 24 at the face within the recess 23, the bolt extending approximately centrally through the tube 28 and through the closure or plug 29 thereof. The outer end of this bolt 30 carries a nut 32 which when tightened draws the plug 23 into tightly fltting engagement with the outer end of th metals-tube,v

tub e upon the 13085 -27 o'f the plied, and the outer edge of this connector 33 is frame of the motor it. A spring-22 is disposed in each bushing I9, .'under compression between I! or I8. The portions of the line wire L at the break are connected'at theouter ends of the bushings 19 in any suitable manner, and through the latter to the brushes l2 and I3.

Th rotatable member I4 is provided in its outer end face with a shallow recess 23 which is circular in shape but eccentricto the axis of rotation of the shaft II, and Ya support or disk 24, preferably of insulating material, is mounted in The support 24 has a circularperiphery which approximately fits th circular recess .23, so as to provide a rotatable connection between the support 24 and member l4. The support or disk 24 is secured in the recess and clamped in any of diiferent possible rotary positions therein, in any suitable manner, such as by clips or clamping plates 25 which are adjustably secured to the end face of the rotatable member I4, such as by screws 28' that pass through the plates 25 and are threaded into the member l4. The plates 25 overlie somewhat the recess 23, and the disk or support 24 i made connected by a flexible conductor or wire 34 to one of thecollecting rings, such as the ring l8, in any suitable manner. Similarly a flexible wire or conductor 35 is connected at one end to the metallic tube 28 and at its other end to the other collector ring II. A globule 36 of liquid mercury is disposed within the chamber of the tube 28, and the globule is of a size such that when it rests upon or abuts against the surface of the inner periphery of the tube 28 which is farthest from the axis of rotation, it will Just nicely contact with and engage the rod 38 so as to form an electrical connection between the tube 28 and the rod 30. Such a position is shown by the position of the globule in full lines in Fig. 1 and also in Fig. 3.

The globule should not fill the entire chamber of the tube, so that it can expand in a direction endwise of the chamber, that is, in direction parallel to the axis of rotation, and it may also be free tov expand in a direction circumferentially of the tube 28. It will be understood that in 'Fig. 1 the globule is shown as resting against the zone of the wall of the tube which is farthest from the axis of rotation, which is the position it will occupy when the motor is operating. When the motor is not running, how-' ever, the globule will drop .to the bottom of a thicker than the depth of the recess, so that the plates 25, as they extend over the recess 23. will overlap and bear upon the marginal edge of the support 24. When the screws 26 are tightened, the plates 25 will draw the disk or support 24 into the recess 23 and frictionally clamp it in any position in the recess into which it has been rotated.

The support or disk 24 has a cylindrical boss 21 projecting endwise therefrom, eccentrically to the center of the disk or support 24 and hence eccentrically to the recess 23. A cylindrical, metal tube28 is; fitted at one end over the bos chamber of the tube 28, such as into the position 1 shown by the dotted lines in Fig. 1 and designated A. Itwill be noted that in the position A in Fig. l, the globule alsocompletes the circuit between the tube 28 and the rod 30. If th position of the motor is varied so as to shift the tube 28 into different positions out of horizontalthe globule 36 will, during idleness of the motor, al-,,

ways maintain a contact between the tube 23 and the rod 30. For'example, if the tube 28 is tipped into an upright or vertical po'sitionsuch as would be occupied if the shaft H :01 the motor 1 were disposed vertically, the globule 36 of mercury will rest against an end of the chamber of g the tube 28 and, because it still retains its globulev form, it will electrically connect the tube 28 and ;will function in the same way, because, due to will remain in that zone under the influence of centrifugal forces, at which time the forces of gravity on the globule become substantially nil or negligible and may be substantially disregarded in controlling the speed of the motor or the operation of the switch. The globule of mercury has a high surface tension, so that it tends to maintain its globular form when conflned against the wall zone of the tube 28 which is farthest from the axis of rotation, and thus will maintain a contact between the tube 28 and the rod 38 while the rotation of the shaft H continues. As the speed of rotation of the shaft ll increases, the intensity of the centrifugal forces acting on the globule 36 of mercury and tending to overcome the surface tension of the globule and flatten it against the wall of the inner circumference of the tube 28, will increase, and when the rotating member has reached a predetermined speed, this deformation or flattening of the globule of mercury will be sufllcient to cause the globule to leave contact with the rod 38. open the circuit in the line wire L and thus cut off the flow of current to the motor. The motor will then decrease in speed until the centrifugal forces acting on the globule decrease and allow the globule to resume its former shape, due to surface tension acting on the globule, and reestablish contact between the globule and the tube 28. Thus current will flow to the motor only when the speed of the motor is below predetermined speed, and the action will be entirely automatic.

Owing to the completion and opening of the circuit through the mercury globule, there will be very litle arcing in the mercury globule, and such arcing as does occur cannot injure the mercury or the rod 30. As usual in mercury contacts. the chamber of the tube 28 will preferably be filled with an inert gas, so that there is very little or no arcing when the circuit is opened, and any arcing that does occur will not materially injure the mercury or the rod 38. There will be no arcing between the globule and the tube 28 because they always remain in contact. It will be observed that since the mercury by centrifugal force always tends to seek the wall zone farthest from the axis of rotation, the governor will work satisfactorily in all different positions in which the motor, governor and the globule may be placed, and since the forces of gravity acting on the globule are relatively insignificant compared with centrifugal forces acting on the globule, the action of gravity will be negligible in its effect on the openng and closing of the circuit through the globule. The centrifugal forces which really control the closing and opening of the circuit at the globule during rotation of the motor will not be materially modified by the influence of gravity and will be equally effective and of the same value whether the governor is disposed in one position or another.

The position of the globule when it withdraws from contact with the rod 38 is shown in Fig. 4 in full lines, and in Pg 1 by the dash lines B. The expansion or deformation of the globule, as it is flattened by centrifugal forces, will be largely in directions parallel to the axis of rotation, because the globule is urged by centrifugal forces as far as possible from the axis of rotation, and any material expansion alon the peripheral surface of the tube would carry it towards the axis of rotation which is resisted by centrifugal forces. By rotating the support 24 within the recess 23 Lin .into different positions, the extent of eccentricity of the tube 28 with respect to the axis of rotation may be varied, and since the centrifugal forces acting on the globule and tending to flatten it and open the circuit vary proportionally to the radius of rotation of the globule about the axis of rotation, it will be seen that by varying the extent of eccentricity of the tube with respect to the axis of rotation, the speed at which the circuit will be opened may be controlled and thus the speed of the motor equally controlled. A protective casing 81 may be carried by the periphery of the rotatable member I and extending into enclosing relation over the tube 28 and the other parts mounted on the outer end face of the member ll so as to avoid any danger of electrical shock to any one through accidental contact with the conductors, and also to protect against injury to any one who might otherwise be hit by the eccentrically mounted parts on the member I 4.

In the embodiment of the invention illustrated in Fig. 5. the construction is similar to that shown in Figs. 1 to 4, except that the support 2la, which corresponds to the support 24 of Figs. 1 to 4, instead of be ng rotatably mounted in the recess 23, is in the form of an arm which is pivoted to the member I near one edge thereof, such as by a screw 38, so that by swinging the support 24a about the pivot screw 38, the tube 28 and the parts associated therewith may be shifted to different distances away from the axis of rotation of the shaft II. The free end of the arm or support 24a is provided with a slot 39 whose center of curvature is at the pivot 38, and a clamping screw passes through this slot 39 and isthreaded into the rotatable member l4, so that by tightening the screw 48, the arm or support 24a may be clamped in different adjusted positions on the member I4. A suitable scale 8| may be provided on the face of the member l4, and the arm or support 24a may have a pointer 42 which cooperates w'th the scale to aid one in setting the tube 28 to any extent of eccentricity on the member l4 within the limits provided for. After an adjustment of arm 2411 the tightening of the screw 40 will maintain that adjustment.

In both of the particular embodiments of the invention which have been described and illustrated above, the liquid globule is described as of mercury because the globule must be of electricity conducting material with a substantial surface tension and should not wet the surfaces of the chamber against which it abuts. While other liquids having similar properties may be employed, liquid mercury is preferable for this purpose because it has an unusually high surface tension and tends to form a more or less globular form when a relatively small quantity is placed on a surface or in a chamber. The word globule is intended to refer to a relatively small body of liquid which has sufficient surface tension to draw the body into a somewhat globular or generally ball-like form when placed on a surface which it will not wet, in distinction to the use of a relatively larger quantity which in effect forms a bath in the chamber and which, because of the relatively larger quantity, conforms to the shape of the chamber instead of forming the more or less ball-like shape. By the use of the globule, or the mass which maintains its own shape which is different from that of the chamber in which it is placed, the governor will work in any position and at a much higher speed than any generally similar governor utilizing a bathtype body of contact liquid.

In a switch employing a bath-type body of contact liquid, a relatively larger body of conducting liquid such as mercury is disposed in a circular or cylindrical container, and when the container is rotated about an axis concentric to the container, the liquid immediately forms a skin-like, continuous film along the inner surface of the container, and either connects or disconnects electrodes projecting into'the chamber. In such cases any appreciable speed will immedi ately cause the skin-like surface to form, thus being useful only for relatively low speeds, but by the use of the globule it is possible to rotate the governor at a much higher speed before it alters the circuit. By having the chamber in which the globule is placed eccentric to the axis of rotation, the globule or liquid body tends to remain together in the same body, instead of spreading out as a skin-like coating, and maintains more or less its same form, except as modified by the centrifugal forces which tend to flatten the globule against the surface,

It will be understood that the wall against which the mercury globule is confined during the rotation, should have a greater length or dimension in at least one direction than the width of said globule so that the globule when flattened mayexpand and thus draw away from the central electrode 30 which is spaced from the other electrode such as the conducting surface. As a matter of simplicity, the tube 28 is formed entirely of conducting material, and forms one of the conductors or contact terminals within the chamber, the clamping rod 30 being utilized as the otherconductor, This arrangement is advantageous and provides a very simple, inexpensive and practical arrangement, but it will be un-' derstood that the body of' the tube may be of other material, with a conducting surface disposed along the inner surface thereof, particularly in the part occupied by the globule during rotation, which would be the wall zone which is farthest from the axis of rotation. By having the conducting surface extend around substantially the entire surface of the chamber of tube 28, the circuit will always be closed when the mo tor stops, regardless of the position of the motor.

When a bath is rotated eccentrically it assumes its final shape having an inner surface concentric with the axis of rotation just as soon as the forces of gravity become negligible. Rotation at a higher speed would scarcely alter the shape of the bath. Thus a bath rotated eccentrically, if practical at all, could be used only at very low speeds of rotation to open and close a circuit, and the forces of surface tension would have no appreciable effect. Any conducting liquid, regardless of whether its surface tension was high or low, would give the same results with a'rotating bath, whether rotated concentrically or eccentrically;

It will also be understood that various other changes in the details, materials and arrangements of parts, which have been herein described and illustrated in order to explain the nature and principle of the invention, may be made by those skilled in the art within the principle and scope of the invention, as expressed in the appended claims.

I claim as my invention:

1. A switch device for controlling an electric circuit which comprises a rotatable member, a hollow element rotatable with said member and having spaced, opposing, electrically conducting surfaces in the chamber thereof and insulated from one another, one of said surfaces forming that portion of the surface of said chamber approximately farthest from the axis of rotation of said member and being formed of a material which is not wet by liquid mercury, the other of said conducting surfaces being disposed nearer said axis than said one surface, means for connecting said surfacee;.to terminals of said circuit during rotation of said element with said member, and a globule of mercury disposed in said chamber and of such size that its surface tension draws it into a generally ball-like form independently of the forces of gravity and that it will engage with and electrically connect said conducting surfaces when said globule is supported by said surface portion farthest from said axis of rotation and is subjected only to the action of gravity and insuflicient to cover said one surface, whereby when said element is rotated about said axis, the centrifugal forces acting on said globule in opposition to the forces of surface tension will tend to flatten said globule against the outermost of said' conducting surfaces and pull away from said axis while said globule remains relatively stationary on said surface portion farthest from said axis, and separate from the other of said conducting surfaces to open said circuit at said globule by such flattening while in the same relative position on said surface portion.

2. A switch device for controlling an electric circuit whiclrcomprises a hollow element Having spaced, electrically conducting, circuit conductors in the chamber thereof and insulated from one another, a globule of mercury disposed in said chamber, of a size to engage with and electrically connect said conductors when said globule is subjected only to the action of gravity and insufllcient to fill said chamber, and to retain its ball-like shape, and means mounting said element for rotation about an axis eccentric to said globule when said globule connects said conductors, said chamber having that portion of its encircling surface wall which is engaged by said globule when the globule connects said conductors, disposed farthest from said axis of all portions of said wall, and farther from said axis than one of said conductors, and also having a shape and size enabling said globule to retain its globular form but to flatten and thicken during its rotation, whereby when said chamber and globule are rotated about said axis, said globule will tend to flatten out against said wall portion while remaining relatively stationary thereagainst and, when a predetermined speed of ro tation is reached, separate from said one of said conductors and open the electric circuit between said conductors.

3. A' switch device for controlling an electric circuit which comprises a hollow element having spaced, electrically conducting, circuit conductors in the chamber thereof and insulated from one another, a globule of mercury disposed in said chamber, of a size to engage with and electrically connect said conductors when said globule is subjected only to the action of gravity and insufiicient to fill said chamber, and means mounting said element for rotation about an axis eccentric to said globule when said globule connects said conductors, said chamber having that portion of its encircling surface wall which is engaged by said globule when the globule connects said conductors, disposed farthest from said axis of all portions of said wall, and farther from said axis than one of said conductors, and also, having a shape and size enabling said globule to retain its globular form but to flatten and thicken during its rotation, whereby when said chamber and globule are rotated about said axis, said globule will tend to flatten out against said wall portion and, when a predetermined speed of rotation is reached, separate from said one of said conductors and open the electric circuit between said conductors, said chamber being adjustable on its mounting to different distances from said axis to vary the speed at which said globule will separate from said one of said conductors and thereby opens the circuit between said conductors.

4. An improved switch of the type having two circuit controlling terminals to be connected and disconnected, and comprising a chamber having one wall zone, a globule of mercury confined in said chamber and engageable with said wall zone, and of a size to retain a generally ball-like shape by the action of its surface tension, said wall having greater length in one direction than the width of said globule, means for rotating said chamber and globule about an axis eccentric to said chamber but with said wall zone farther from said axis than the other zones of said wall, whereby said globule will be confined against said wall zone and without translation therealong and flattened thereon by centrifugal forces due to such rotation, and spaced conducting terminals insulated from each other and disposed in said chamber for engagement with said globule when said globule is confined against said wall zone and subjected to the influence of gravity alone, and one of them spaced from said wall zone towards said axis for disengagement from said globule when the latter is flattened against said wall by centrifugal forces created by said rotation at a predetermined speed while remaining in the same position on said wall zone.

5. An improved switch of the type having two circuit controlling terminals to be connected and disconnected, and comprising a chamber having one wall zone, a globule of mercury confined in said chamber, and of such size that its surface tension overcomes the action of gravity and draws the globule into generally ball-like shape, and engageable with said wall zone, said wall having greater length in one direction than the width of said globule, means for rotating said chamber and globule about an axis eccentric to said chamber but with said wall zone farther from said axis than the other zones of said wall, whereby said globule will be confined against said wall zone and, while remaining relatively stationary on said wall zone, flattened thereon by centrifugal forces due to such rotation, and spaced conducting terminals insulated from each other and disposed in said chamber for engagement of both of them with, and disengagement of at least one of them from, said globule when said globule is confined against said wall zone and subjected to different centrifugal forces, due to different predetermined speeds of rotation, that change its shape.

6. An improved switch comprising a rotatable member, a hollow element mounted on said member for rotation therewith and having an approximately cylindrical chamber therein with its longitudinal axis approximately parallel to and at one side of the axis of rotation of said member. a conductor rod extending endwise through said chamber, the wall forming the cylindrical chamber being of metal, and the ends of said chamber being of insulating material, collecting rings on said member, one connected to said metal cylindrical wall and the other connected to said rod, brushes bearing on said collecting rings for establishing circuit connections to said metal cylindrical wall and said rod during their rotation with said member, and a globule of mercury in said chamber of a size to contact said rod and said cylindrical wall when said element is quiet but free to move endwise in said cylinder and also of such size that its surface tension overcomes the action of gravity and draws the globule into a generally ball-like shape, whereby when said member is rotated about said axis, the mercury while confined against the outer, cylindrical wall of said chamber will provide a connection between said rod and the metal cylindrical wall while confined against the portion of the cylindrical wall farthest from the axis of rotation, but will pull away from said rod and open the circuit through said chamber when the centrifugal forces acting on said mercury are suflicient to flatten it against the cylindrical wall in opposition to its surface tension until it leaves contact with said rod.

7. An improved switch comprising a rotatable member, a hollow element mounted on said member for rotation therewith and having an approximately cylindrical chamber therein with its longitudinal axis approximately parallel to and at one side of the axis of rotation of said member, a conductor rod extending endwise through said chamber, the wall forming the cylindrical chamber being of metal, and the ends of said chamber being of insulating material, collecting rings on said member, one connected to said metal cylindrical wall and the other connected to said rod, brushes bearing on said collecting rings for establishing circuit connections to said metal cylindrical wall and said rod during their rotation with said member, and a globule of mercury in said chamber of a size to contact said rod and said cylindrical wall when said element is quiet but free to move endwise in said cylinder, whereby when said member is rotated about said axis the mercury will provide a connection between said rod and the metal cylindrical wall while confined against the portion of the cylindrical wall farthest from the axis of rotation, but will pull away from said rod and open the circuit through said chamber when the centrifugal forces acting on said mercury in opposition to the surface tension of the globule are sufficient to flatten it against the cylindrical wall until it leaves contact with said rod, said element being adjustable on said member to carry said chamber to different extents away from said axis of rotation so as to vary the centrifugal forces acting on said mercury and tending to flatten it, and thus vary the speed of rotation at which the circuit is interrupted.

8. A switch device for controlling an electric circuit which comprises a rotatable member of insulating material, a support of insulating material adjustably secured to a face of said member which is transverse to the axis of rotation of said member and adjustable thereon in a direction crosswise of said axis, a metal cylindrical tube mounted on the end face of and closed by said support so as to extend therefrom in a direction parallel to said axis, an insulating closure for the outer end of said tube, a metal rod extending approximately centrally of said tube between said support and closure and clamping the closure to tube and the tube to the support, a P

collecting rings carried by said member, a flexible conductor connecting one of said rings with said rod, another flexible conductor connecting the v metal tube to the other of said rings. brushes bearing on said rings to form electrical connections therewith during rotation of said member,

and a globule of mercury in said tube of a size of a predetermined speed, said hollow element be-- ing adjustable on said member in a direction crosswise of the axis of rotation so as to carry saidelement laterally toward and from said axis to different extents so as to vary the speed at which the centrifugal forces will be suflicient to separate said globule from said conductor, by

' centrifugal forces. v

to contact said rod but not fill said chamber when I subjected only to the action of gravity and when said tube is in an approximately horizontal position, whereby said mercury will normally complete a connection between said-brushes through the chamber of said tube, but will tend to flatten against a wall zone of said tube by centrifugal forces acting on the globule while said member is rotating, and when a predetermined speed is reachedthe flattening of the globule will be suflicient to draw away from said rod and open the circuit between the brushes. I

9. A switch device for controlling an electric circuit which comprises a rotatable member, a hollow element mounted on said member for rotation therewith, said element having a cylindri-- cal chamber therein whose axis extends approximately parallel to the axis of rotation of said member but located at one side thereof, said chamber having a conducting surface extending along the interior face of the cylindrical wall thereof, a conductor extending approximately through the center of the chamber of said element in an endwise direction and approximately parallel to'saidcylindrical wall but spaced therefrom, a globule of mercury disposed in said chamber of a size to touch said conductor but not fill said chamber when the globule of mercury is resting on the cylindrical wall of the chamber, and is under the influence of gravity alone, and

when the axis of the chamber is approximately horizontal, and means for establishing circuit connections to said conductor and to said con- 1 ducting surface during their rotation with said member, whereby the mercury normally provides an electric connection through said chamber but flattens out and leaves contact with said conductor when subjected to the centrifugal forces created by the rotation of said member in excess of a predetermined speed.

10. A switch device for controlling an electric circuit which comprises a rotatable member, a

hollow element mounted on said member for roparallel to said cylindricalwall but spaced there-- from, a globule of mercury disposed in said chamber of asize to touch said conductor but not fill'said chamber when the globule of mercury v .is resting on the cylindrical wall of the chamber, and is under the influence of gravity alone, and

when the axis of the'chamber is approximately horizontal, and means for establishing circuit connections to said conductor and to said conducting surface during their rotationfwith said member, whereby the mercury normally provides an electric connection through said chamber but flattens out and leaves contact with said conductor when subjected to the centrifugal forces v created by the rotation of said member in excess 11. A switch device for controllin an electric circuit which comprises a member of insulating material having a pair-.of parallel faces and mounted for rotation about an axis normal to said faces, a pair of collecting rings on one of said faces, a support of insulating material secured against the other face and having a cylindrical boss projecting therefrom in a direction parallel to said axis, a metallic tube fitting over and closed by said boss, a plug of insulating materlal closing the other end of said tube, a metallic. rod extending between said support and plug for drawing the same toward one another and clamping said plug and tube to said support, and effectapproximately horizontal and the globule is resting on the portion of the cylindrical zone of said tube which is the farthest from the axis of rotation and which globule is shorter in length than the chamber in said tube, whereby said globule may expand endwise when flattened by centrifugal action and' when so expanded endwise will withdraw from contact with said rod and open the circuit between said rings.

12. A switch device for controlling an electric circuit which comprises a member of insulating material having a pair of parallel faces and mounted for rotation about an axis normal to said faces, a. pair of collecting rings on one of said faces, a support of insulating material secured against the other face and having a cylindrical boss projecting therefrom in a direction parallel to said axis, a metallic tube fitting over and closed by said boss, a plug of insulating material closing the other end of said tube, a metallic rod extending between said support and plug for drawing the same toward one another and clamping said plug and tube to said support, and effecting a closure of the chamber of said tube, a conductor. connecting one end of said rod and one of said rings, a conductor connecting the tube and the other of said rings, brushes bearing on said rings during said rotation, and a globule of mercury disposed in the chamber of said tube and of a size to touch said rod when said tube is approximately horizontal and the globule is resting on the portion of the cylindrical zone of said tube which is the farthest from the axis of rotation and which globule is shorter in length than the chamber in said tube, whereby said globule may expand endwise when flattened by centrifugal action and whenso expanded endwise will with;-

draw from contact with said rod and open the of different positions in which said tube is dis-- posed at difierent distances from the axis of rotation, whereby the speed at which the globule flattens and interrupts the circuit through said tube may be varied selectively .by the placing of said tube in different ones of said positions.

13. A switch device for controlling an electric circuit which comprises a pair of spaced conductors in series in said circuit, a globule of a conducting liquid having a high surface tension and of such size that its surface tension overcomes the forces of gravity thereon and holds it in a generally ball-like shape, supported in contact with one of said conductors and making contact with the other of said conductors by virtue of its globular shape due to its surface tension overcoming the normal leveling action of gravity, and means for changing the shape of said globule substantially in opposition to the forces of surface tension in a manner to break contact of said globule with one of said conductors, which said globule remains relatively stationary with respect to the other of said conductors.

14. A switch device for controlling an electric circuit which comprises a pair of spaced conductors in series in said circuit, a globule of a conducting liquid having a high surface tension and of such size that its surface tension overcomes the forces of gravity thereon and holds it in a generally ball-like shape, disposed to normally make contact with said conductors by virtue of the globular shape of said liquid due to its surface tension overcoming the normal leveling action of gravity and to break contact with at least one of said conductors when the shape of said globule is changed in one dimension, and means for changing the shape of said globule in said one dimension by modification of forces opposing the action of the forces of surface tension while the globule remains otherwise in the same relation to said conductors.

15. The improved apparatus for controlling an electric circuit between two spaced conductors of said circuit which comprises said conductors, a globule of mercury of such size that its surface tension draws it into a generally ball-like shape, disposed in contact with said conductors to complete a circuit therebetween, a wall spaced from at least one of said conductors and abutting said globule and along which said globule may expand in at least one direction and of a material which said mercury will not wet, and means for rotating said wall, globule and conductors about an axis eccentric to said wall and globule and thereby creating centrifugal forces tending to flatten said globule against said wall, without dividing said globule or changing its position on said wall, and which when a predetermined speed of rotation is reached, will flatten said globule sufficiently to separate said globule from contact with at least one of said conductors to open said circuit.

16. The improved apparatus for controlling an electric circuit between two spaced conductors of said circuit which comprises said conductors, a globule of mercury of such size that its surface tension overcomes the forces of gravity and draws it into a generally ball-like shape, disposed in contact with said conductors to complete a circuit therebetween, a wall spaced from one of said conductors and abutting said globule and along which said globule may expand in at least one direction and of a material which said mercury will not wet, and means for rotating said wall, globule and conductors about an axis eccentric to said wall and globule and thereby creating centrifugal forces tending to flatten said globule against said wall, without dividing said globule or changing its relative position upon said wall,

and which, when a predetermined speed of rotation is reached, will flatten said globule sumciently to separate said globule from contact with at least one of said conductors to open said circuit, said means having a portion adjustable to vary the degree of eccentricity of said globule and wall with respect to said axis and thereby vary the speed of rotation at which said globule separates from said one of said conductors.

17. The improved switch which comprises a free globule of a liquid having substantial surface tension and of such a size that its surface tension overcomes the action of gravity and draws the globule into a generally ball-like form, a wall of a material not wet by said liquid and against which said globule is disposed and along which it may expand in at least one direction, means for flattening said globule against said wall and releasing it to cause lateral distortions of said globule tending to expand and contract it in said one direction, while said globule remains undivided and in the same relative position on said wall, and conducting means disposed to be connected and disconnected by such distortion of said globule.

18. The improved apparatus for controlling an electric circuit.between two spaced conductors which comprises said conductors, a globule of liquid having a surface tension and such size that the forces of surface tension acting thereon overcome the action of gravity normally tending to flatten the globule and maintain the globule in a somewhat spherical shape, a support for disposing said globule in a position to make and break contact with said conductors when the shape of said globule is changed, and means for distorting said globule in shape, in opposition to its surface tension, to different extents from its somewhat spherical, lobular shape while it remains undivided and in the same position on said support by applying flattening forces opposing the surface tension forces without destroying said globular form, whereby said conductors may be electrically connected and disconnected solely by the varying distortion of said globule.

19. The improved apparatus for controlling an electric circuit between a pair of conductors in response to speed, which comprises said conductors of a material not wet by mercury, a surface of a material not wet by mercury, a globule of mercury of such size that its surface tension overcomes the forces of gravity acting thereon and draws said globule into a somewhat ball-like form when freely supported on said surface, disposed on said surface with freedom to flatten thereon, and in a position to connect and disconnect said conductors as said globule changes its globular form, and means for subjecting said globule while said globule retains its same position on said surface against which it is disposed to centrifugal forces dependent upon said speed which distort said globule into different degrees of flattening without loss of its globular form, depending in extent of flattening upon the size of said centrifugal forces, whereby the connection and disconnection of said conductors by said globule will be responsive to said speed.

20. An improved electric switch comprising a globule of'mercury of such size that its surface tension overcomes the forces of gravity and draws it into a generally ball-like form, means for flattening said globule to different extents from its normal ball-like form without dividing it, in opposition to its surface tension, and circuit means including a conductor disposed to be engaged with and disengaged from said globule during and only because of changes in the shape of said globule caused by said means and said surface tension, and while said globule is as a mass relatively stationary with respect to said conductor.

21. A mercury tube switch for centrifugal operation comprising a constant diameter tubular metallic envelope, a rod-like electrode insulatedly supported by the envelope and extending axially into and along substantially the entire length of the envelope, an insulating member surrounding saidelectrode adjacent one end of the envelope; means for revolving the switch; means mounting the switch with its axis fixed substantially parallel to and eccentrically of the axis of revolution of said revolving means and a limited quantity of mercury in said envelope; whereby said mercury may tend to form a globular mass at any position along said envelope at one side of said insulating member and normally be in contact with said electrode to completea circuit between the electrode and the envelope, and upon revolution of the switch bodily with axis parallel to the axis of revolution, said mass will flatten and'withdraw from said electrode contact.

22. A mercury tube switch for centrifugal operation comprising a sealed, tubular, metallic envelope; a rod-like electrode insulated and supported from the envelope extending axially into and substantially throughout the entire length of the envelope; means for revolving the switch; means mounting the switch with its axis fixed substantially parallel to and eccentrically of the axis of revolution of said revolving means; and mercury in the envelope limited in quantity to form normally a localized mass in any position along the envelope tending to assume a globular form suflicient in depth to contact both the envelope and the electrode; whereby upon bodily revolution of the switch may cause at a critical speed a flattening of the mercury mass to'break said contact.

not wet by it and against which it is confined,

means forrotating said chamber about an axis eccentric to said chamber, to create centrifugal forces on said body that will confine said body 1 against the portion of said interior surface farthest from said axis and to flatten said body, while for establishing circuit connections to said conducting means as the chamber rotates.

24. The electric switch substantially as set forth in claim 23, and means for adusting said chamber relatively to said axis to vary the degree of eccentricity of said chamber and thereby vary the speed of rotation of the chamber at which said centrifugal forces will change the shape of said body sufilciently to make or break a circuit therethrough.

25. An electric switch comprising a closed chamber filled with an inert atmosphere and having an interior surface of a material not wet by mercury, means for rotating said chamber about an axis eccentric thereto, a body of mercury within and only partially filling said chamber and of such size that a substantial portion thereof is drawn by its surface tension away from the zone of said surface against which said body may be confined, whereby when said chamber is 'so rotated said body will be confined by centrifugal forces, relatively immovably against that portion of said interior surface which is farthest from said axis, a conductor disposed within said chamber in a position to contact with and separate from said body as the latter changes its shape beyond selected limits, with changes in speed of rotation, under the opposing actions of centrifugal forces and surface tension, and means for including electric-ally in series, said body of mercury and said conductor.

26. The switch substantially as set forth in claim 25, and said rotating means including a mounting'for said chamber by which said chamber may be shifted toward and from said axis to vary the speed at which said mercury and con.- ductor engage or separate.

' HARRY L. LAMBERT.

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