US2150634A - Time control switch - Google Patents

Description

March 114, 1939.

' TIME CONTROL SWITCH SSheets-Sheet 1 Filed March 20, 1957 FIGZ.

FIGI.

March 14, 1939.

M. H. RHODES TIME CONTROL SWITCH a Sheet-Sheet 2 Filed March 20, 1937 March Ii4, 1939. M H, RHQDES; 2,150,634

TIME CONTROL SWITLGHE Filed March 20 195;? 3 Sheets-Sheet. 3i

Patent ed Mar. 14, 1939 PATENT OFFICE TIME common. swrrcn Marcus H. Rhodes, New York, N. Y., assignmto M. H. Rhodes, Inc., New York, N. Y., a corporation of Delaware Application March 20, 1937, Serial No. 32,019 8 Claims. (c1. 200-39) This invention relates to electric switches, and

with regard to certain more specific features, to electric time-controlled switches.

The present invention is in the nature of an improvement on the invention shown and claimed in my copending application Serial No. 673,421, filed May 29, 1933, now Patent No. 2,087,071 dated July 13, 1937. g

Among the several objects of the invention may be noted the provision of an electric switch of the class described having a plurality of circuit male ing and breaking positions, part of said positions being time-controlled, and part being independent of time control; the provision of an electric switch of the class described which is particularly adapted for the operation of electrical resistance heating units, such as used :in electrical stoves, so that a tiined period of high heat may be had, after which a period of relatively lower heat will commence and continue until a manual turning off operation is carried out; the provision of an electric time-controlled switch of the class described which has but one handle for both is relatively simple in construction and opera- 7 construction, and arrangements of parts which win be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is illustrated one of various possible embodimentsof the invention,

Fig. 1 is a front elevation of a time-controlled switch embodying the present invention;

Fig. 2 is a back elevation of the switch shown in Fig. l;

Fig. 3 is a plan view of a base forming a part of the switch of Fig.1, and is also a cross section taken along line 3-3 of Fig. 4;

4 is a cross section taken substantially along line H of Fig. 3;

Figure 5, 6, and 7 are views similar to Fig. 3 showing alternative positions of certain elements; Fig. 8 is a fragmentary cross section taken substantially along line 88 of Fig. 6;

Fig. 9 is a horizontal cross section taken substantially along line 9-9 of Fig. 4; and,

Fig. 10 isa perspective view of a latch lever. Similar reference characters indicate corresponding parts throughout the several views of the drawings.

In my aforesaid copending patent application, I have shown a form of electric time-controlled switch which is of great advantage in that it has but a single operating handle for controlling both the turning oil and on of the switch, and for setting the time interval for which the switch is to automatically operate. It is a pri-= mary purpose of the present invention to retain this structural characteristic of a single handle, but to additionally incorporate within the switch structure an electrical switch, operable from the same handle, but controlling another set of cir .cuit conditions.- This additional switch, in the present invention, is a non-time-controlled switch, c9 consequently it is operated only by its manual actuation of the single handle heretofore re ferred to. At the same time, said handle is avail able for all of the purposes found in my aforesaid copending application. g5 Referring nown ore particularly to l, will be seen that the switch of the present invention is enclosed in a housing indicated generally by numeral i. Rotatably mounted at the center of the upper face of the housing 11 is a knob 32. This knob 3 is mounted on the end of a main shaft 5 (see Fig. 4) hereinafter to be described in greater detail. A projection i molded in the housing l serves as a stop to prevent the rotation of the knob 3 in the wrong direction. The upper. face of the casing i contains index characters positioned to cooperate with the knob said index characters being circularly arranged about the face of the casing and comprising an oil position 8, a low position ii, and a numbered, J graduated scale l3. Thev numbers of the scale l3 indicate the particular delay for which the switch is set at any given instant. A dot or other suitable indicating mark [5 is alsoprovided on the face of easing l; for purposes to be explained hereinafter. D

- The rear face or base ll of the casing l, as shown in Fig. 2, .mounts the terminals of the switches of the present invention, which comprise three binding posts l9, 2|, and 23. The character of the switching elements within the switch, hereinafter to be described, are such that p when the knob 3 points to the o position 9,

none of the terminals I9, 2|, and 23 are connected together; when the knob 3 points to the low position connections are made inside the switch between terminals I9 and 2| but not between terminals 2| and 23; but when the knob 3 is in suitably actuated position anywhere on the scale l3, connections are not only made between terminals l9 and 2|, but also between terminals 2| and 23, with an automatic time delay device running to disconnect the terminals 2| and 23 after the expiration of a predetermined time interval.

From this brief description of the function oi the switch, its utility in a circuit connection such as for the heating elements of an electric stove can be seen. Diagrammatic circuit connections are indicated'in Fig. 2 for this purpose. For example, index characters and 21 indicate a pair of power wires. The wire 21 is connected to the terminal 2|. Terminal I9 is connected, through a relatively high resistance 29, to the other wire 25, while terminal 23 is connected, to a relatively low resistance 3|, to the same wire 25. The resistances 29 and 3| are considered as embodied in a single heating unit. When the knob is suitably actuated and is in any position on the scale l3, since terminals l9, 2|, and 23 are all connected together, resistances 29 and 3| will be connected in parallel across the power wires 25 and 21. The current will therefore be relatively high, and the heating eilect will accordingly be great. However, on expiration of the pre-set time interval, connection will be broken between terminals 2| and 23, and hence resistance 3| will drop out of circuit and only resistance 29 will be connected across the wires 25 and 21. Since resistance 29 is relatively high,- the current flow will be considerably less, and the heating eilect will accordingly be diminished. This condition takes place when the knob 3 has reached the "low': index position Low heat will continue as long as the switch is allowed to remain untouched, but when the knob 3 is manually turned from low" position II to of! position 9, connections are additionally broken between the terminals l9 and 2|, and therefore neither of the resistances 29 or 3| will receive current and the heating means will accordingly be disconnected entirely.

The arrangement described is of considerable utility in connection with cooking, for example, where it is desired to cook a food for a certain length of time at a relatively high temperature, after which a long slow simmering period at lower heat is needed. Or, the low heat period may be considered as merely a warming period during which the food, properly cooked during the "high heat" period, is kept warm for serving purposes.

The general character and utility of the switch having thus been described, its construction will now be gone into in greater detail.

Broadly speaking, the time-controlled switch comprises two parts, namely, the mechanical switching mechanism and the time delay mechanism, which are interconnected by a series of latches and the like. For clarity, the mechanical switching mechanism will first be described, and thereafter the time delay mechanism, while the two will be correlated in connection with the description of the operation of the switch as a whole.

The mechanical switching mechanism is mounted entirely upon the base |1. It comprises a pair of terminals 33 and 35 (see Fig. 3), which are supported on projections 31 and 39, respectively, molded integrally with the base l1. Each terminal comprises a fiat piece of brass having a portion 4| which fits into a companion receiving depression in the projections 31 and 39, and an outwardly extending, knife-edged portion 43. Terminal piece 35 also has a sidewardly extending brass plate mounted concentrically therewith, the end of the piece 45 serving as a fixed contact for one of the switching devices. Numeral 41 indicates a third terminal piece that is likewise mounted on the base l1. The terminal piece 41 supports a curved spring 49, the edge of which appears in Fig, 3. On the free end of the spring 49 is mounted a camming plate 5|. The tendency of the spring 49 is normally to engage the end face of the contact plate 45, to make electrical connection between the terminals 35 and 41, but when a suitable camming device is brought to bear against the plate 5|, the end of spring 49 is lifted away from the end of plate 45, thereby to break connections.

The terminals 33, 35, and 41 are each mounted on the base l1 in the manner illustrated in Fig. 4 for terminals 33 and 35. An inwardly threaded hollow cylinder 53 is molded permanently into the base l1, and extends therethrough. The inner end of the cylinder 53 is upset as at numeral 55 to clamp the respective portions 4| of the terminals. Into the outer end of thecylinders 53 are threaded the binding post screws l9, 2|, and 23, which screws comprise the means for -making exterior connections to the switch.

Mounted on a pin 51 which is supported in the base I! (see Figures 3 and 4) is a rotating contactor bar assembly. This assembly comprises a spacing washer 59, a double-blade contactor bar per se 5|, a second spacing washer 53, and an anvil piece 55. The contactor bar 5| has two arms 51 and 59, which extend radially from the pin 51 in such directions thatwhen one engages the terminal 33, the other will be engaging the terminal 35. The arms of the bar 5| each comprise two spaced blades of spring material, such as copper, brass or bronze, and each blade terminates sidewardly with flared lips 1|, so as the better to engage the terminals 33 and 35. The anvil piece 55 preferably comprises fiber or similar material, and includes, on its upper surface, a substantially rectangular notch 13. A projection 15 from contactor bar 5| fits into a hole 11 in the anvil piece 55, whereby rotation of the anvil piece 55 relatively to the contactor bar 5| is positively prevented.

It will readily be seen that through rotation of the anvil piece 55, the terminals 33 and 35 may be connected or disconnected at will with the coextensive rotation of the contactor bar 5|. The devices thus far described may be characterized as the electrical elementsof the mechanical switching mechanism.

The switch operating mechanism is in part mounted upon a pin 19 which is supported in base H (see Figures 3 and 8). Mounted on the pin 19 is a swingable hammer saddle member 8|, which comprises an arm 83, at the upper end of which is a hole through which the pin 19 passes, a cross piece 85, and a portion 81 parallel to.thc arm 83. On the cross piece 85 is a nose 89, the function of which will be indicated hereinafter. The arm 83 is of suitable length such that the cross piece 85 at all times fits within the notch 13 in the anvil piece 55. Swinging of the hammer saddle 8| is limited by a pair of projections 9| molded on the base |1.

Mounted on a second pin 93, supported in base l1 in a manner parallel to but spaced from pin 19, is a member 95, which comprises a plate 91 ill which is parallel to the axis of the pins 19 and 93, but displaced therefrom, and a pair of pro- J'ections 99 extending at right angles from the plate 91 and drilled to slide on the pin 93. The plate 91'is drilled to receive one end of a ten- ,sion spring II, the other end of which is an- The compression spring I09, member 95, and' hammer saddle 8| together constitute an overcentering device, as follows: When the member 95 is rotated counterclockwise, against the spring IOI, and the hammer saddle 8| is held stationary by reason of its'engagement with the upper (Fig. 3) projection 9| (in other words, when the member 95 is rotated counterclockwise from its position as indicated in Fig. 3), the compression spring I09 is slowly compressed against the nose 89 on the hammer saddle 8|, until a point is reached where the nose 89, the axis of the spring I09, and the nose I01 are all in line and radial to the pin 93. As the member 95 passes this position, the force of the compression spring is liberated by its swinging the hammer saddle sharply downwardly, in a clockwise manner, until it is stopped by the lower projection 9|. -The reverse action .takesplace when the member 95 is returned to its original position, as it rotates clockwise under the force of spring IOI, and the hammer saddle is swung sharply upwardly in a counterclockwise manner. As the hammer saddle swings, its cross piece 85 is forced sharply against opposite sides of the notch 13 in theanvil piece 65, thus snapping the contactor bar 81 into and out of connection with the terminals 33 and 35. In this manner contacts are made and broken with a much to-be-desired snap action, and thus arcing and sparking, and consequent pitting and erosion of the contacts is avoided.

This substantially completes the description of the mechanical switching mechanism, and the time delay mechanism will next be described.

The time delay mechanism, broadly, comprises a main spring, an escapement train permitting said main spring to unwind itself only in a slow, controlled. manner, .and a latch device which cooperates with the mechanical switching device to operate the same. The time delay mechanism is mounted between two brass plates H and H1 (see Figures 4 and 9), which are spaced apart by collars M9 on screws |2|.' The plate H5 is in turn mounted on pillars I23 projecting from base I1, by means of screws I25 that extend through to the exterior of the base I1. The plate I I5 desirably is provided with holes for receiving the upper ends of pins 19 and 93, to aid in supporting said pins.

The time delay mechanism as a whole. operates upon the main shaft 5, which, it will be remembered, extends from the front of the switch housing. Said shaft 5 is borne in the plates I I5 and H1, and has mounted thereon, immediately beneath the plate II1, a coiled main spring I21, the inner end of which is securely amxed to said shaft. The outer end of the main spring I21 is secured to a projection I29 struck from the relatively immovable plate II1. Similar pro- :Iections I29 are provided at spaced intervals around themain spring I21, serving to hold it in position. The inner edge of main spring I21 is protected by 'a. cover plate I3I, which is secured to the shaft 5, and is rotatable therewith.

Immediately behind the cover plate I3I a collar I33 is mounted on the main shaft 5, the collar I33 serving to space a main gear I35. The gear I35 rotates freely on and relative to the main shaft 5. Immediately behind the main gear I35 is a spring disc member I31, which comprises a central portion which is secured to the shaft 5 against rotation relative thereto, and-a dished or flanged periphery I39 which is sprung to bear forcibly upon the surface of main gear I35. The frictional force of the periphery I39 on the gear I35 is such that, when the main shaft 5 is manually rotated, as in setting the switch, the disc I31 slips freely on the surface of the gear, without carrying it in coextensive rotation, but when the main spring alone is tending to unwind, through the escapement train, the slow force is sufficient that the gear I35 is compelled to rotate simultaneously with the main shaft 5. This arrangement constitutes a form of clutch, in which engagement is had provided the force is applied to the driven member in a very slow, uniform manner, but in which no engagement is had if.

the force is applied quickly and unevenly (as it is with manual rotation of the main shaft 5).

9 Behind the disc I31 on'the shaf'; 5 is mounted a small disc |4|, which has a projection I43 in its own plane. The disc MI is immovable relative to the shaft 5. Its function will be indicated hereinafter.

,Engaging the main gear I35 is a pinion I45, which constitutes the first element of av timing or escapement train. The escapement train will not be described in great detail herein, since it may be of the same general type as those shown in my Patents Numbers 1,895,398 and 1,895,399, dated January 24, 1933. Broadly, it comprises a series of pinions I45 and gears I41, which are arranged one gear and one pinion to a shaft,

eachshaft being supported in bearings in the plates 5 and H1, and which together effect a large increase (or decrease) in angular rotation from the main shaft 5 to an escapement mechanism I49. The escapement I49 comprises a toothed wheel I5I and a balance wheel I53, the latter being mounted on a balance staff I55 having a notch I51 therein which, together with a pin I59 mounted on the balance wheel I53 allows the escapement wheel I5I to rotate only one tooth at a. time, and at definite intervals. For a further description of the escapement mecha nism, reference is made to my Patent No. 1,995,363, dated March 26, 1935.

It will now be seen that the operationof the timing means is substantially as follows: Assume that the device is initially run down and at rest. The shaft 5 is manually rotated in a direction to wind the main spring I21 (this direction being counterclockwise in Fig. 9). As the main spring is wound, the clutching mechanism I31 slips and the main gear I35 remains stationary. However, whenever the winding is stopped, the clutching means I31 immediately 7 takes hold of the gear I35, and further rotation without rotating the main gear I36, and the main gear I36 can rotate only in a very slow, timed manner as controlled by the escapement mechanism and gear train. Thus, the main shaft 6, after once having been wound, can unwind under its own power only at a predetermined, slow speed. If the shaft 6 is rotated manually in a clockwise (unwinding) direction, however, the clutch I31 again slips and the main spring may be manually returned to run down" position without awaiting the action of the escapement mechanism.

Supported on a pivot screw I6I (Fig. 9) which is mounted on the under side of plate H6 is a latch lever I63, the particular construction of which is indicated in Fig. 10. Referring to Fig. 10, it will be seen that the lever I63 comprises a stamping of relatively thin sheet metal or the like which has the general shape of an approximately squared C. A hole I66 at one corner provides for the pivot screw I6I. At the same corner, a projection I61 is bent upwardly from the lever I63, and in assembly this projection I61 receives one end of a tension spring I89 (see Fig. 9), the other end of which is hooked around a post II9 mounted on the upper side of plate II6. Projection I61, it will be understood, extends across the edge of plate II6. Spring I68 tends at all times to rotate lever I63 on pivot I6I in a counterclockwise (Fig. 9) manner. Returning to Fig. 10, the short end of the lever I83, considered from pivot I6I, is provided with a cumming nose I13 which in operation engages the camming plate 6i on movable contact spring 49 (see Figures 3, 5, 6, and 7). Near its other corner, the lever I63 is provided with a stamped projection I16, an end I11 on which is positioned, in assembly, to interrupt the swinging motion of hammer saddle 8I of the mechanical switching assembly. The far end of lever I63 includes an upwardly-turned projection I19, which passes, in assembly, through a suitable arcuate slot I8I in plate II5 (see Fig. 9) in position to engage (or disengage) projection I43 on disc I4I on shaft 6.

Numeral I83 (Fig. 9) indicates a dog that ispivoted on the upper or inner surface of plate II6 on a pivot screw I85 mounted in said plate IE6. The dog I83 has a projection I81 extending in one direction to be in position to intercept the movement of projection I43 on disc I on main shaft 6, while in the other direction it extends out over the edge of plate II6 and is provided with a downwardly-turned ear I88 which is positioned to engage and disengage ear II3 on portion III of member 96 of the mechanical switching mechanism. A tension spring I9I reacts between projection I89 and one of the screws H9, and tends at all times to turn dog I83 in a clockwise (Fig. 9) direction.

The above completes the description of the various elements of the mechanical switching device and the time delay mechanism. The conjoint operation of the two will now be described.

Assume, again, that the device is unitially in run down position, the main spring being unwound. The mechanical switching elements are in their position as indicated in Fig. 3, all connections being off. The main shaft 6 is now manually rotated, as by turning knob 3, in a direction adapted to wind the main spring. During the first few degrees of rotation, projection I43 on disc I moves from its solid-line, Fig. 9 position, to its dotted-line position, and in so doing permits projection I19 on lever I63 to follow it under the action of spring I68, likewise moving from its solid-line position to its dotted line position. This means that nose I13 of lever I63, which heretofore has been bearing on camming plate 6I of spring contact arm 48, as shown in Fig. 3, will be lifted thereirom, permitting said spring contact arm 46 to abut the fixed contact plates 46, as shown, for example, in Fig. 7, thereby to complete the circuit between exterior terminals I9 and 2|. By the time the projection I43 has reached its dotted-line, Fig. 9 position, the knob 3 will be located at the low index position II, Fig. 1. Further rotation of the main shaft 6, will cause the projection I43 on disc I to abut the projection I81 on dog I83, and rotate said dog in a clockwise (Fig. 9) manner on its pivot I86. In so moving, projection I88 of dog I83 is brought to bear forcibly against projection III of member 86, and said member 86 is caused to rotate on its pivot pin 63 in a counterclockwise (Fig. 3) direction. As heretofore described in connection with the operation of the mechanical switching device, this rotation of the member 86 will cause a snapping rotation of the hammer saddle 3|, with the result that the anvil piece 86 is rotated on its pivot 61, and the contactor bar assembly is rotated to the Fig. 5 position, where exterior terminals 2| and 23 are now connected together.

In moving to its Fig. 5 position, the hammer saddle 8| will have ridden over the projection I11 on lever I63, and lodged therebehind, as shown in Fig. 5. Until this projection I11 is removed, therefore, the hammer saddle BI is not permitted to swing in a reverse manner.

As the knob 3 is rotated still further, projection I89 passes out of engagement with projection H3, and since the engagement of these projections was the only force urging the member 96 to rotate in a counterclockwise direction, against its own spring IIII, the moment this engagement stops the spring IOI will act to return the member 96 to its original position. This it proceeds to do, and the member assumes the position shown in Fig. 6. However, with this return movement of the member 85, the hammer saddle 8| cannot cooperate, because of its engagement with the projection I11 of latch lever I63. The return movement of the member 96, however, cooks the compression spring I09 into position to snap the hammer saddle back to its original position as soon as the projection I11 is removed; in other words, the Fig. 6 position, which by this time has been assumed, is one in which the hammer saddle M is cocked to throw the anvil piece 66 in a clockwise rotation as soon as the latch projection I11 is removed, thereby to break connection between exterior terminals 2| and 23.

By this time, the knob 3 in its rotation will have passed the dot or other suitable index mark I6, as shown in Fig. 1. Instructions to the user of the switch should specify that, for any controlled operation, the handle 3 should first be rotated past the dot I5. Thereafter, the knob 3 may be set to any desired location on the scale I 3,

for any desired time interval, be it greater or lesser than the time interval represented by the position of the dot I5 relative to the scale I3.

In the Fig. 6 position of. the elements, both switches are now on. While all of the foregoing has been going on, the main spring has been wound, but the clutch I31has been slipping to prevent rotation of the main gear I35 of the timing train. The time delay to be set, it will be seen, is proportional to the rotation of the main shaft in the winding direction;

Assuming that the requisite delay has been set, the rotation of the knob 3 and main shaft 5 is stopped, the escapement means immediately comes into operation in the manner specified, allowing the main shaft to return or to run down only at a measured, slow speed. Nothing happens until the knob 3 nears the "low" index position II, when the projection I43 of disc I engages the reverse face of projection I81 'of dog I83. In this direction of movement, however, projection I43 is able to force dog I83 aside, against the action of spring I9I, since there is no obstruction present to the counterclockwise (Fig. 9) rotation of the dog I83. Finally, the projection I43 passes the dog I83, and again assumes its dotted-line (Fig. 9) position. Continuing the movement, the projection I43 now begins to bear against the projection "9 of latch lever I63, causing said lever to rotate on its pivot I6I against its spring I69. The first thing that happens is that the latch lever I63 is rotated sufficiently far so that the projection I" is removed from its effective holding position against the hammer saddle 8|. Thereupon, instantaneously, the cooked compression spring I09 swings the hammer saddle 8| back to its original or rest position, as shown in Fig. 7, thereby disconnecting the co tactor bar assembly from the terminal pieces 33 and 35 and opening the circuit between the exterior terminals 2| and 23. The opening of the circuit between'the terminals 2i and 23 is ,thus performed in an automatic, timed fashion. The exterior terminals I9 and 2|, however, are still connected together by the movable spring contact 49. At this stage of operation, represented in its entirety by Fig. '7, the knob 3 will have reached the low index position II on the face of the switch, as indicated in Fig. 'l.

The timing train and escapement mechanism now stalls, because its power is not sufficient to move the latch lever I53 against the reaction of spring contact arm 49. If, however, the knob 3 is manually grasped and rotated back to off index position 9, this remaining motion of the main shaft 5, in order to bring the projection I43 of disc I4Ito its full-line, Fig.9 position, is'manually brought about, and in so doing the latch lever I53 is further rotated an amount sufficient to force the nose I13 thereof to bend spring contact arm 49 away from fixed contact 45, thus breaking the connection between said spring contact arm 49 and the fixed contact 45, and there-.

fore breaking connection between. the exterior terminals I9 and 2|.

When the knob 3 is thus returned'to its off index position 9, all of the elements will again have resumed their full line, Fig. 9 position, and the positions indicated in Fig. 3,and the device will be ready for a subsequent manipulation.

Itwillreadily be seen that at any time while the time delay is running (in other words, at any time after the device has reached the position indicated in Fig. 6), the knob 3 may be manually grasped and returned to low index position II, with the result that exterior connections between terminals 21 and 23 are broken. This sometimes. happens in the event that it is suddenly desired to d scontinue the high heating "period. Similarly. the additional manual operation required to disconnect exterior terminals I9 and 2I (return of the knob 3 of off index position 9) may be accomplished at any time.

. In view of the above, it will 'be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended tion or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A time-controlled switch comprising a manually rotatable main shaft, a pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotation of said main shaft through a given angle to move one of said switches from one to another position, and additional means operable upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said that all matter contained in the above descripadditional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position.

2. A time-controlled switch comprising a mam ually rotatable main shaft, a pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotation of said main shaft through a given angle to move one of said switches from one to another position, and additional means operable upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and-upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said additional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position, said timing train including a main spring which is likewise connected to said main shaft to be tensioned by the rotation thereof.

3. A time-controlled switch comprising a manually rotatable main shaft. a pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotation of. said main shaft through a given angle to move one of said switches from one to another position, and additional means operableupon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said additional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path ofsaid additional means to permit said second switch to return to its first position, said timing train including a main spring which is likewise connected to said main shaft to be tensioned by the rotation thereof, the time interval during which said latching means is operable being directly proportional to the angle through which said main shaft is rotated.

4. A time-controlled switch comprising a man ually rotatable main shaft, a pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotaton of said main shaft through a given angle to move one of said switches from one to another position, and additional means operable upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said additional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position, said first-named means comprising a cam.

5. A time-controlled switch comprising a manually rotatable main shaft, a pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotation of said main shaft through a given angle to move one of said switches from one to another position, and a ditional means operable upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position,

' a latching mechanism operated by the rotation of said main shaft and interposable in the path of said additional means thereby to prevent, temporariiy, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position, said additional means comprising an over-centering device, and camming means arranged for rotation with said main shaft and cooperating with said over-centering device for the actuation thereof.

6. A time-controlled switch comprising a manually rotatable main shaft, 2. pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotation of said main shaft through a given angle to move one of said switchesfrom one to another position, and additional means operable upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said addi-- tional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position, said additional means comprising an over-centering device, a dog, and a cam mechanism affixed to the main shaft for rotation therewith, the said cam mechanism driving the dog to drive the over-centering device when the main shaft is rotated in one direction, but per mitting the free passage of said dog when said main shaft is operated in the opposite direction.

7. A time-controlled switch comprising a manually rotatable main shaft, a pair of electric switches each having open circuit and closed circuit positions, means connected to said main shaft operable on rotation of said main shaft through a given angle to move one of said switches from one to another position, and additional means operable upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said additional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position, said switches having a common terminal.

8. A time-controlled switch comprising a manually rotatable main shaft, a pair of electric switches each having open circuit and closed cir cuit positions, means connected to said main shaft operable on rotation of said main shaft through a given angle to move one of said switches from one to another position, and additional means operable'upon rotation of said main shaft through a given greater angle to move the second switch from one to another position, and upon rotation through still a greater given angle to urge said second switch back to its first position, a latching mechanism operated by the rotation of said main shaft and interposable in the path of said additional means thereby to prevent, temporarily, said second switch from being returned to its first position, and a timing train operative after a predetermined time interval to remove said latching mechanism from the path of said additional means to permit said second switch to return to its first position, said first-named switch including spring means of sufficient strength that it is impossible, for said main shaft to be rotated against said spring means only under the action of said timing train.

MARCUS H. RHODES.

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