CONDITION CONTROL DEVICE AND SYSTEM

• US 3,599,006 A
• Filed: 08/14/1969
• Issued: 08/10/1971
• Est. Priority Date: 08/14/1969
• Status: Expired due to Term

• Current Assignee: John L. Harris
• Original Assignee: John L. Harris
• Inventors: Harris, John L.
• Application Number:
  US04/850,012
• Time in Patent Office: 726 Days
• US Class Current: 307/39
• CPC Class Codes: G05B 19/063 for sequential programme-control without delivering a reference value
• CPC Class Codes: H02P 1/58 sequentially

Abstract

A number of compressor motors or electric beaters are turned on and off in sequence to avoid line surges. Each load switch consists of two flexible blades raised by a cam with the contacts separated. A latch serves to hold one blade up when the blades are lowered by the cam, causing contact engagement. A solenoid releases the latches of all the switches to open them simultaneously in response to a thermostat becoming satisfied or indicating an unfavorable condition. Special circuitry protects against compressor short cycling when the control is applied to refrigeration.

Claims

1. In a control system for a condition changing system having a plurality of condition changing units, the combination of, a condition responsive device, motor driven actuating means, means for starting said actuating means in response to a predetermined condition at said condition responsive device, a plurality of load switches connected to different condition changing units, means operated by said motor driven actuating means for mechanically actuating said load switches in sequence thereby activating the condition changing units in sequence when the condition responsive device calls for a condition change, control means for stopping said motor driven actuating means after it has operated the load switches to activate the condition changing units, a control device, means mechanically connecting said control device with said load switchs for actuating said load switches independently of said motor driven actuating means in a manner to deactivate the condition changing units when the control device is moved in one direction, means mechanically actuated by movement of the control device in said one direction for actuating said control means in a manner permitting continued operation of the motor driven actuating means, and means for actuating said control device in said one direction in response to a predetermined condition.

2. The combination as set forth in claim 1 in which the control means for the motor driven actuating means consists of a motor switch connected in circuit with the motor, said motor switch being operated in one direction by the motor driven actuating means after the load switches are actuated in sequence, said motor switch also being operated in the opposite direction by the control device substantially simultaneously with actuation of the load switches by said control device.

3. The combination as set forth in claim 2 in which the motor driven actuating means closes the load switches and opens the motor switch in sequence and in which the control device is an electric magnet which on deenergization opens the load switches and recloses the mOtor switch substantially simultaneously.

4. The combination as set forth in claim 1 in which the control device is an electromagnet and in which a single condition responsive device controls both the electromagnet and the motor driven actuating means, the load switches being closed in sequence in response to one condition at the condition responsive device, and being opened substantially simultaneously in response to another condition at the condition responsive device.

5. The combination as set forth in claim 1 in which the condition responsive device controls only the motor driven actuating means, and the control device is actuated by a separate condition responsive device responsive to a condition of the condition changing system.

6. In a control system for a condition changing system having a plurality of condition changing units, the combination of a condition responsive device, motor driven actuating means, means for starting said actuating means in response to a call for condition change by said condition responsive device, a plurality of load switches connected to different condition changing units, means operated by said actuating means for mechanically actuating said load switches in sequence, thereby activating the condition changing units in sequence when the condition responsive means calls for a condition change, means for stopping said actuating means when the load switches have been actuated for activating the condition changing units, said motor driven actuating means also being arranged to mechanically operate said load switches in sequence for deactivating the condition changing units in sequence upon continued movement of said actuating means, means for restarting the actuating means in response to the condition responsive means becoming satisfied, thereby deactivating the condition changing units in sequence, a control device, means actuated by said control device for mechanically operating said switches in a manner to deactivate the condition changing units substantially simultaneously and independently of said motor driven actuating means, and means for actuating said control device in response to a predetermined condition for causing simultaneous deactivation of said condition changing units.

7. The combination as set forth in claim 6 in which the control means for the motor driven actuating means consists of a motor switch connected in circuit with the motor, said motor switch being actuated in one direction by the motor driven actuating means after the load switches are actuated in sequence, said motor switch also being operated in the opposite direction by the control device substantially simultaneously with operation of the load switches by said control device.

8. The combination as set forth in claim 7 in which the load switches are closed to activate the condition changing units and the motor switch is closed to stop the motor by shunting the same and in which the control device is an electromagnet which upon deenergization opens the load switches and the motor switch.

9. In a control system for a condition changing system having a plurality of condition changing units, the combination of, a condition responsive device having a switch which closes upon call for condition change and which opens when satisfied, control means including a motor driven actuator having a drive motor and a plurality of switches connected to different condition changing units, said actuator being arranged to actuate said switches in sequence as the actuator moves from an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' position to a '"'"''"'"''"'"''"'"'run'"'"''"'"''"'"''"'"' position, said actuator also being arranged to open said switches when the actuator returns from the '"'"''"'"''"'"''"'"'run'"'"''"'"''"'"''"'"' position to the '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' position, a power source for the drive motor capable of being shunted without damage, first circuit means including a first motor control switching means controlling power to the drive motor, said first motor control switching means being actuated by the actuator and said circuit means and switching means beIng connected and arranged to place the drive motor in circuit with the condition responsive device switch when the actuator is in the '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' position, and to provide an independent circuit for the drive motor when the actuator is away from the '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' position, second circuit means including a second motor control switching means, said second circuit means being connected and arranged to shunt the power source in series with the condition responsive device switch, said second motor control switch being operated by the actuator and arranged to close when the actuator is in the '"'"''"'"''"'"''"'"'run'"'"''"'"''"'"''"'"' position.

10. In a control system for a condition changing system having a plurality of condition changing units, the combination of, a condition responsive device, motor driven actuating means, said actuating means comprising a plurality of actuators and a motor for driving same, a plurality of load switches connected to different condition changing units, said load switches being operated by different actuators and individually comprising a first switch blade, a second switch blade, cooperating contacts carried by the switch blades, the first switch blade being biased toward the second switch blade tending to cause engagement of the contacts, the second switch blade being biased in the same direction tending to cause disengagement of the contacts, means including one of said actuators for moving both of said switch blades against their bias with the contacts separated to predetermined position and then releasing the blades, a plurality of latches, said latches being arranged to support the second switch blade of different load switches after release by the corresponding actuator for causing engagement of the load switch contacts, control means controlled by the condition responsive device for starting said motor driven actuating means in response to a predetermined condition thereby activating said condition changing units, control means for stopping said motor driven actuating means after it has operated the load switches to activate the condition changing units, and means including a latch actuator for actuating said latches to release said latches in response to a predetermined condition, thereby opening said load switches.

11. The combination as set forth in claim 10 in which the control means for the motor driven actuating means consists of a motor switch connected in circuit with the motor, said motor switch being operated in one direction by the motor driven actuating means after the load switches are actuated, said motor switch also being operated in the opposite direction by the latch actuator when it releases the latches.

12. The combination as set forth in claim 11 in which the motor driven actuating means closes the load switches and opens the motor switch in sequence, and in which the latch actuator is operated by an electromagnet which on deenergization releases the latches and recloses the motor switch.

13. The combination as set forth in claim 11 in which an electromagnet operates the latch actuator and in which the condition responsive device controls both the electromagnet and the motor driven actuating means, the load switches being closed in sequence in response to one condition at the condition responsive device and being opened substantially simultaneously in response to another condition at the condition responsive device.

14. The combination as set forth in claim 10 in which the condition responsive device controls only the motor driven actuating means, and the latch actuator is actuated by a separate condition responsive device responsive to a condition of the condition changing system.

15. In a controller for sequentially controlling a plurality of loads, the combination of, a plurality of load switches, motor driven actuating means for actuating said load switches, said actuating means comprising a plurality of actuators and a motor for driving the same, said load switches being operated by different actuators and individually coMprising a first switch blade, a second switch blade, cooperating contacts carried by the switch blades, the first switch blade being biased toward the second switch blade, said second switch switch blade being biased in the same direction, means including one of the actuators for moving both of the switch blades against their bias to predetermined positions and then releasing said blades, a plurality of latches, said latches being arranged to support one of the switch blades of different switches after release by the corresponding actuator, control means for stopping the motor driven actuating means after it has released said switches, and means for releasing said latches and operating said control means to permit continued operation of said motor driven actuating means.

16. The combination defined in claim 15 in which the control means for stopping the motor is a switch in circuit with the motor and having a latch for maintaining it closed, said last mentioned latch being released with the other latches.

17. In a multiple switch controller, the combination of, a plurality of switches, motor driven actuating means arranged to mechanically actuate said switches, a series of separate and independently mounted latches arranged to hold said switches in actuated position, means for releasing one of said latches, and means actuated by releasing motion of said one latch for engaging and releasing another of said latches.

18. The combination as set forth in claim 17 in which the first latch is provided with a camming surface arranged to cause additional movement of the latch after movement to releasing position, said additional movement being imparted by the switch it released and causing movement of said other latch in releasing direction.

19. In a timing device, a cam, first and second switch blades carrying cooperating contacts and each biased toward said cam, means providing a first cam follower surface carried by the first switch blade and riding the cam, means providing a second cam follower surface carried by the second switch blade and riding the cam, said cam having a main camming surface and a dropoff section, the cam follower surfaces and the switch blades being arranged to provide a gap between the contacts when both cam follower surfaces are riding the main camming surface of the cam, a latch arranged to support one of the switch blades in a manner to cause and maintain engagement of the contacts after the cam follower surfaces have been passed by the dropoff section of the cam, and means for releasing said latch to cause disengagement of said contacts.

20. The combination defined in claim 19 in which the means for releasing the latch is actuated with the cam and releases the latch at a predetermined position of the cam.

21. The combination set forth in claim 19 in which the means for releasing the latch consists of an electromagnet arranged to release the latch upon actuation thereof.

22. The combination set forth in claim 20 in which an electromagnet is arranged to release the latch independently of the first named latch releasing means.

23. In a control system for a condition changer, circuit means including a load switch for controlling the condition changer, operating means for the switch including a motor driven actuator, said operating means including actuated means raised by motion of the motor driven actuator and lowered when the actuator reaches a predetermined position, said operating means also including a latch movable from latching to releasing position and vice versa, the latch and actuated means being constructed and arranged to cause operation of the switch to start the condition changer when the actuated means is lowered with the latch in latching position and to stop the condition changer when latch is moved to releasing position, means including condition responsive device arranged to start the motor driven actuator from a first position in response to a predetermined condition, means for stopping the motor driven actuator in a second position after it has started the condition changer, means for releasing the latch and restarting the motor driven actuator in response to a predetermined condition and means for stopping said motor driven actuator at said first position.

24. The combination as set forth in claim 23 in which the means for stopping the motor driven actuator consists of a motor switch controlling the motor of the motor driven actuator, said switch being held open by a latching means released substantially simultaneously with the load switch latch.

25. In a control system for a refrigeration system having a compressor, the combination of, a power circuit for the compressor, control means for said power circuit including a condition responsive device, a timing device, and an electromagnet, control circuit means including the condition responsive device, the timing device and the electromagnet for causing closure of said power circuit to start the compressor in response to a call for condition change, the control circuit means also being arranged to open the power circuit in response to the condition responsive device becoming satisfied, the timing device being arranged to interpose an equalization delay between opening and closure of the power circuit sufficient to allow suitable pressure equalization in the system and to provide an additional delay in event of a short cycle, the overall time cycle of the timing device including both delays, means for causing operation of the timing device through the additional delay period when the compressor starts and for stopping the timing device at the end of this period if the compressor is still in operation, means for restarting the timing device when the compressor is stopped, and means for stopping the timing device when the equalizing period is substantially consumed.

26. In a control system for a refrigeration system having a compressor, the combination of, a power circuit for the compressor, control means for said power circuit including a condition responsive device a timing device, and an electromagnet, control circuit means including the condition responsive device, the timing device and the electromagnet for causing closure of said power circuit to start the compressor in response to a call for condition change, the control circuit means also being arranged to open the power circuit in response to the condition responsive device becoming satisfied, the timing device being arranged to provide an initial delay period between call for condition change and starting of the compressor, an equalization delay period between opening and closure of the power circuit sufficient to allow suitable pressure equalization in the system, and an additional delay period in the event of a short cycle, the overall time cycle of the timing device including all three delay periods, the condition responsive device being arranged to start the timing device on call for refrigeration and the timing device initiating said closure of the power circuit for the compressor at the end of said initial delay period, means for causing operation of the timing device through the additional delay period when the compressor starts and for stopping the timing device at the end of this additional delay period if the compressor is still in operation, means for restarting the timing device when the compressor is stopped, and means for stopping the timing device when the equalizing period is substantially consumed if the condition responsive device is not calling for refrigeration.

27. In a control system for a condition changing system having a plurality of condition changing units, the combination of, a plurality of switches connected to different condition changing units, an electric motor driven actuating means arranged when started from a first predetermined position to actuate said switches in sequence thereby activating the condition changing units in sequence, an operating condition responsive controller responsive to the load on the system, means conTrolled by said operating condition responsive controller for causing the motor driven actuating means to run from the first position and activate the condition changing units in sequence when the operating condition responsive controller calls for condition change, means controlled by said controller for stopping the actuating means in a second predetermined position allowing continued operation of the condition changing units, means for restarting the motor driven actuator and actuating the switches to terminate operation of the condition changing units when the operating condition responsive controller becomes satisfied, means controlled by the condition responsive controller for stopping the motor driven actuating means at the first predetermined position, protective means including an electromagnet for operating said switches to terminate operation of the condition changing units independently of said motor driven actuator means, a protective condition responsive controller in circuit with both the electromagnet and the motor of said motor driven actuating means, said protective controller acting to terminate operation of the condition changing units and prevent running of the actuating means when an undesirable condition occurs in the system.

28. In a control system for a condition changing system, the combination of a power circuit for said condition changing system, control means for said power circuit, said control means including an operating condition responsive device responsive to the load on the system, a protective condition responsive means responsive to a condition in the condition changing system, a timing device, and an electromagnet, control circuit means including the operating condition responsive device, the timing device and the electromagnet for causing closure of said power circuit to start the condition changer in response to a call for condition change, and to open the power circuit in response to the operating condition responsive device becoming satisfied, means in said control circuit means whereby the timing device interposes a delay between opening and closure of said power circuit, means in the control circuit means to start the timing device when the operating condition responsive device becomes satisfied if the protective condition responsive device indicates a satisfactory condition in the system, means in the control circuit means whereby said protective condition responsive means operates the electromagnet to open the power circuit independently of the operating condition responsive device in response to an unfavorable condition in the system, and means in the control circuit means to render the timing device inoperative to begin a timing cycle as long as the condition is unfavorable and render the timing device operable when the condition becomes favorable, whereby the duration of the unfavorable condition is added to the delay provided by the timing device.

29. In a control circuit for a condition changing system including a condition changer and fluid moving means associated therewith, the combination of, a first power circuit for the condition changer, a second power circuit for the fluid moving means, control circuit means for the power circuits including an operating condition responsive device responsive to the load on the system, a protective condition responsive means responsive to a condition in the condition changing system, and a timing device, said control circuit means being arranged to close both power circuits to start the condition changer and fluid moving means in response to a call for condition change by the first condition responsive device and to open the first power circuit to stop the condition changer in response to said first condition responsive device becoming satisfied, the timing device being arranged to control the second power circuit to maintain it closed for operating the fluid moving means a period of time after the condition changer is stopped, control circuit means arranged to start the timing device When the operating condition responsive device becomes satisfied if the protective condition responsive device indicates a satisfactory condition in the system, the protective condition responsive means being arranged to cause opening of the first power circuit to stop the condition changer, and to prevent the timing device from operating in response to an unfavorable condition, whereby the fluid moving means is maintained in operation as long as the unfavorable condition exists.

30. The combination set forth in claim 29 in which the timing device is also arranged to interpose a delay between stopping and restarting of the condition changer.

31. In a control system for a condition changer, a condition responsive device, a power circuit for the condition changer, a control system for the power circuit including said condition responsive device, a timing device and an electromagnet, means whereby said timing device causes closure of the power circuit at the command of the condition responsive device, and the electromagnet causes opening of the power circuit independently of the timing device when said electromagnet is deenergized, means including a condition responsive device and circuit means connecting said condition responsive device and electromagnet and arranged to deenergize the same in response to an unfavorable condition associated with the condition changer, switching means actuated by said timing device also in circuit with the electromagnet, said switching means being connected and arranged to deenergize said electromagnet independently of said second condition responsive device during periods when the power circuit is open, and means whereby said timing device operates the switching means to energize the electromagnet for allowing continued closure of the power circuit under the command of the first condition responsive means when the second condition responsive means indicate a favorable condition.

32. In a motor driven switching mechanism, a motor, a cam shaft driven by said motor, said cam shaft carrying a plurality of cams, a plurality of switches operated from one contact position to another by said cams, said cams being arranged to operate said switches in sequence, starting from a predetermined angular starting point of the cam shaft, means other than the cam shaft for returning at least one of the switches to said one position, mechanical interlocking means between said switches, said mechanical interlocking means being arranged to prevent one of said switches from being operated to its other contact position if a switch ahead of it is not in its other contact position, whereby the cam shaft must return to the starting position before said one switch can be actuated to its other contact position.

33. The combination set forth in claim 32 in which the switches are provided with separate control elements having active and inactive positions and arranged to require the control element of a given switch to be in active position in order for such switch to be in its other contact position, the mechanical interlocking means extending between said control elements.

34. The combination set forth in claim 33, in which the control elements are latches which must be in latching position in order for the corresponding switch to assume its other contact position.

35. In a control system for a condition changer having a plurality of condition changing units, the combination of, a plurality of switches connected to different condition changing units, electric actuating means for actuating said switches, an operating condition responsive controller, means controlled by said operating condition responsive controller for causing said electric actuating means to operate said switches to start the condition changing units in response to call for condition change, said electric actuating means being arranged to stop said condition changing units in sequence in response to the condition responsive controller becoming satisfied, and protective means including an electromagnet arranged to actuate said switches simultaneously to stop operation of said condition changers, said electromagnet being operated in response to a malfunction and actuating said switches independently of said electric actuating means.