US1995877A - Selective system - Google Patents

Description

March 26, 1935. J. L. WOODWORTH SELECTIVE SYSTEM Filed March 21, 1934 InvniBor: John LWOOdV/OEBH,

His Amowneg.

Patented Mar. 26, 1935 PATENT OFFICE SELECTIVE SYSTEM John L. Woodworth, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application March 21, 1934, Serial No. 716,609

'lClaims.

My invention relates to selective systems and, while not limited thereto, it relates more particularly to that type of selective system in which control operations are selectively effected in response to current impulses of diflerent duration.

One form of selective system to which my invention relates is shown in my Patent No. 1,816,755 issued July 28, 1931 in which a bimetallic strip is utilized selectively to reciprocate a switch member between two positions in response to energization thereof for different periods.

One object of my present invention is to provide a selective system of this type which is more economical to manufacture and which operates with the same or greater degree of reliability.

Still another object of my invention is to provide a novel means whereby a. toggle mechanismmay be selectively actuated to either of its two positions by movement of a thermal element.

The novel features which I believe to be. characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawing in which Figs. 1, 2, and 3 represent one embodiment of my invention; Fig. 4 represents a modification thereof; Fig. illustrates a detail, and Fig. 6 illustrates an application of the form of the invention shown in Fig. 4.

Referring to Fig. 1 of the drawing I have shown therein a relay embodying my invention which is adapted selectively to control a load device 1, such as a lamp, which is energized from a power line 2 in response to carrier currents received thereover. The carrier currents from the power line 2 may be received in any suitable carrier current receiver 3, which may, for example, be of the type shown in my above referred to patent, whereby a relay 4 is actuated. The contacts of relay 4 control the energizing circuit of the actuating element of the selector relay 5 embodying my invention. This actuating element comprises a bimetallic strip 6 having a heating winding 'I wound thereon whereby the strip 6 deflects to the right when the winding '7 is energized. This strip 6 is securely attached to a support 8 by means of a bolt 9 extending therethrough and to which is applied the nut 10. The energizing circuit of the winding 7 of the thermal strip extends from one side of the circuit 2 through the contacts of relay 4, winding '7 and the bimetallic 6 strip 6 to the bolt 9, and thence through the bolt ii and conductor 11 to the other side of the power The switch which controls the load 1 comprises a pair of toggle members 12 and 13, which are pressed by a spring 14 into endwise engagement, the end of the member 13 pivoting loosely in a V-shaped slot 15 in the lower edge of the member 12. The left end of the spring 14 is attached to a supporting member 16, which member is in turn supported from the member 8. The right end ofthe member 14 fits into a notch cut into the upper edge of the pivot member 12 and thus bears down upon this member tending to bias the toggle formed thereby to either of its two off center positions.

Motion of'the toggle to the left, underinfiuence of the spring 14, is restricted by engagement of a contact 17 carried by the member 13 with an additional contact 1'1 which is mounted upon the supporting member 16. This contact controls the circuit of the load, which circuit may be traced from one side of the power line circuit 2 through the loadfll'to contact 17*, thence through contact 1'7 and member 13 to the bolt 9 and nut 10 and thence by conductor 11 to the other side of the circuit. Thus when the toggle is in its left-hand position the load 1 is energized. Movement of the toggle member to the right or to the open circuit position of the switch 1'1, 1'1 is limited by resiliency of the member 13 which opposes the resiliency of the spring 14.

This toggle formed by members 12 and 13 is arranged to be actuated by the thermal strip 6. Its actuation to the right is effected by means of a U-shape member 18, which is best shown in Fig. 5, and which is attached to the upper end of the strip 6. The left arm of this member is arranged, upon movement thereof to the right, to bear against an adjustment screw 19 carried by the member 12. Thus when the bimetallic strip 6 deflects to the right the left arm of member 18 engages the member 19 carrying the toggle over center into its right-hand position. The bimetallic strip also carries a screw 20, arranged for adjustability by means of a lock nut 21, which upon cooling of the bimetallic strip bears against toggle member 12 tending to carry the switch toward the left and into the position shown in Fig. 1. In this position the switch is restrained from further movement by means of a screw 22, which projects through the upper end of the member 12, the right end thereof bearing down on the right arm of the member 18. Thus the position of the toggle shown in Fig. 1 is the normal open circuit position of the switch. In this position the toggle members are just to the left of the center position so that it is biased toward the left but is restrained from further actuation by the bolt 22 bearing down at its right end upon the member 18. V

The operation of the switch in response to carrier current impulses of difierent duration may now be understood. Let us suppose, for example, that a short impulse of carrier current is received from the power line 2. The relay 4 is actuated and the winding 7 energized during the short interval of the impulse. The bimetallic strip 6 is thus caused to deflect slightly to the right. In so deflecting the member 18 moves out from under the bolt 22 thereby releasing the toggle, which under its bias moves to the left. After termination of the short impulse relay 4 opens and the winding 7 is de-energized. Strip 6 then cools and deflects back toward the left the right arm of member 18 abutting against the end of bolt 22. This position of the device is more clearly portrayed in Fig. 2 where it will be observed that the right arm of member 18 abuts against the bolt 22 and that the toggle 12, 13 is in its left-hand position thereby closing the switch 17, 17.

Let us assume now that a carrier impulse of longer duration is received. Member '7 is of course energized as before and causes a larger deflection of the strip 6 toward the right. The left arm of member 18 now abuts against the screw 19. Owing to the tension of the spring 14 further movement is temporarily prevented. Upon further heating of the bimetallic strip 6, however, additional stress is developed in it until a point is reached where the toggle 12, 13 is moved to the right with arapid somewhatsnap like action.

Fig. 3 illustrates the switch in this latter position with the strip 6 fully deflected to the right and the toggle 12, 13 in its extreme right-hand position.

Upon interruption of the carrier wave impulse the bimetallic strip cools and deflects back toward the left. The screw 20 soon engages the toggle member 12 carrying it to the left. Its

' movement to the position shown in Fig. 2, however, is prevented by engagement of the end of screw 22 with the upper edge of the right arm of member 18 whereby the toggle is restrained in the position shown in Fig. 1 andthe contacts 17, 17 are held in their open circuit position.

The screws 19 and 20 are both provided with lock nuts whereby they may be adjusted and retained in any desired position thereby to determine the position of the bimetallic strip when the two members, 20 and the left arm of U shaped member 18, apply force to the member 12. It has been found by positioning the screw 19 fairly-high on the member 12 that actuation of the toggle is delayed until suflicient force is accumulated in the spring 6 to produce a very rapid opening of the switch 17, 17

The bimetallic strip 6 is of course affected by ambient temperatures. To minimize this effect a second bimetallic strip is provided. This bi-.- metallic strip is shown at 6' in Fig. 1 where it is arranged side by side in the same plane with the strip 6, but sufliciently removed therefrom that it is not materially influenced by heat generated by winding 7 on strip 6. Strip 6' is designed to deflect equally with the strip 6 in response to temperature variations but its deflection is in the opposite direction. Since the two ends of the two strips are securely attached on theblock 8 and by the right arm of member 18 one opposes the other with respect to ambient temperature variations to which they are both subjected with the result that ambient temperature effects are minimized. Strip 6', however, is provided with no heating winding and accordingly it is not actuated by operation of the relay 4 with the result that in response to received carrier waves the deflection produced is in the direction of the deflection of member 6, member 6 during this deflection carrying the member 6' with it against the restraint of the latter member.

In Fig. 4 I have shown a further embodiment of my invention which differs from the form shown in Fig. l in that the bimetallic strips 6 and 6' are arranged in broadside relation rather than in edgewise relation as in Fig. 1. The two members are spaced apart at their lower end by a block 23 and at their upper end by collar 24 carried' on screw 20 whereby the two members are sufficiently spaced to prevent the member 6' from being affected by heat generated in the winding 7.

In the form shown in Fig. 4 the relay is provided with an additional contact 25 carried on the end of a spring 26, which is supported from the block 8, and contact 17 projects on both sides of member 13 to cooperate with contacts 17 and 25. The spring 26 is so biased that the contact 25 engages the contact carried by the toggle member 13 when in the position shown in Fig. 4 or in the right-hand position of the toggle which is indicated in Fig. 3. When the toggle is actuated to the left, however, contact 25 is disengaged from the contact carried by the toggle member. Thus the switch 17, 17 25 comprises a single pole double throw switch which in response to a short impulse is actuated to one position and in response to a long impulse is actuated to the other position.

Fig. 6 illustrates an application of utility of the form of the invention shown in Fig. 4 and indicates its use in connection with the off peak control of domestic hot water heaters. In this figure I have indicated at 27 a hot water heater having a large main heating element 28 arranged near the bottom thereof and an additional heating element 29 arranged near the top. Ordinarily the water in the heater is heated by the element 28 and the power consumed therein is measured by watthour meter 30. This watthour meter has a voltage coil which is connected across the power circuit 2 and a current coil which is connected in series with the heating element 28 and the contacts 17 and 17 of the control apparatus 31 provided in accordance with my invention. This apparatus of course includes the carrier current receiver which receives carrier wave energy from the power line to actuate the single pole double throw switch 17, 17 25 of the form of my invention as indicated in Fig. 4. Normally the switch element 17 is at the left so that the heating element 28 is energized. During periods, however, of peak consumption of electric energy it may be desired by the power company to remove the domestic water heaters from the power line. This is eflected by transmitting the long impulse which operates the switch member 17 to the right thereby opening the circuit of the heating element 28.

During this period of peak load the consumer of course utilizes the hot water which is stored in the water heater. It may occur, however, due to the limited storage capacity of the water heater, that this water is insuflicient to supply his needs until the heating unit 28 is again connected to the power line. The consumer may in that event close the switch 35 thereby connecting the auxiliary heating unit 29 across the power line through switch 17, 25 and the current winding of an auxiliary watthour meter 33, the voltage winding of which is connected across the power line 2. Thus the customer is supplied with hot water by means of his auxiliary heating member 29 but the amount of energy consumed is measured upon a second watthour meter thereby enabling the charging of a different rate from that charged for energy consumed by the unit 28. The latter meter 33 may comprise the meter which supplies the customer's lamp load as is indicated by the lamp 34 Fig. 6.

While I have shown particular embodiments of my invention it will 01 course be understood that I do not wish to be limited thereto since difi erent modifications in the mechanical arrangement of elements may be made without departing from the spirit and scope of my invention, and I intend by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a toggle switch having two positions, a thermal element, means whereby said toggle switch is operated from one of said positions to the other in response to a certain degree of heating of said element and said toggle switch is operated from said other position to said one position in response to a different degree of heating of said element, and means to apply heat to said thermal element for difl'erent intervals of time thereby selectively to operate said toggle switch to said positions.

2. In combination, a pair of members spring pressed into endwise engagement to form a toggle, restraining means to prevent actuation of said toggle to one position, thermal means to operate said toggle to another position and means whereby said restraining means is released by said thermal means.

3. In combination, a pair of members spring pressed into endwise engagement to form a toggle, restraining means to prevent actuation of said toggle to one position, thermoelectric means responsive to energization for a certain interval of time to operate said toggle to another position, and means including said thermoelectric means to release said restraining means after en- 'ergization at said thermoelectric means for a different interval of time.

4. In combination, a bimetallic strip, a toggle comprising a pair of members spring pressed into endwise engagement, means normally encasing said bimetallic strip to prevent motion 01 said toggle to one position and for disengaging said bimetallic strip upon small movement thereof in response to heating thereby to release said toggle to fall to said one position, and means whereby upon further movement of said bimetallic strip said toggle is carried to its opposite position.

5. In combination, a thermal element, a toggle mechanism having two positions, and a mechanical connecting means between said thermal element and said toggle mechanism whereby upon small movement of said thermal element from a normal position said toggle mechanism is operated to one of said positions and upon larger movement of said thermal element from said normal position said toggle mechanism is operated to the other of said positions.

8. In combination, a bimetallic strip, a toggle, said toggle being arranged to reciprocate between two members carried by said bimetallic strip, whereby upon moving or said bimetallic strip away irom said toggle said toggle is actuated from one position by one 0! said members over center, and when said bimetallic strip moves toward said toggle said toggle is actuated back toward said one position, and means to restrain said latter movement of said toggle prior to actuation thereof to said one position.

7. A combination 0! a bimetallic strip, a toggle switch comprising a pair of toggle members spring pressed into endwise engagement, a bimetallic strip ca ying a pair of members between which one of said toggle members reciprocates, whereby upon movement of said bimetallic strip away from said toggle members said toggle members are carried by one of said last pair of members from one position over center, and upon movement of said bimetallic strip toward said toggle members said toggle members are actuated toward center by the other of said last pair of members, and a member rigidly attached to said one toggle member and extending at an an gle thereto to engage an edge of said bimetallic strip thereby to restrain said toggle members from movement to said one position.

JOHN L. WOODWORTH.

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