US2231689A - Switch structure - Google Patents

Description

Feb. 11, B. E. SHAW SWITCH STRUCTURE Filed Jan. 2, 1940 pMf-Fa 11, 11941 UNITED STATES SWITCH STRUCTURE Burton E. Show, Bristol, 11111., animor to Penn Electric Switch 00.. Golhen, Ind., a cannontion of 1m Application January 2, 1949. Serial a... 31am My present invention relates to a switch structure particularly adapted for controlling a refrigerant compressor motor of an ice cream freezer system, or the like.

One object of the invention is to provide a switch structure which is normally responsive to the temperature of a freezer so as to control a refrigerant compressor motor and thereby maintain the temperature of the freezer between w predetermined limits, a solenoid being associated with the switch for the purpose of controlling the motor at other specified times.

A further object is to provide the solenoid ar-' ranged under the control of a timer, which timer in performing its normal functions periodically operates a beater or mixer motor of the freezer to keep the contents thereof in a desired smooth and evenly frozen condition.

A further object is to provide a solenoid which go. shunts a beater motor, the solenoid being operable to cut in at somevalue below normal line voltage, such. value being above the voltage to which the line is reduced as a result of starting up of the beater motor, thereby closing the rew frigerant compressor switch after the beater motor has come up to speed.

Still a further object is to provide a standard switch structure responsive to temperature or the like, for normally controlling the refrigm erant compressor motor in response to temperature changes and a solenoid which can be readilyassociated therewith and will effect closure of the switch even though the temperature responsive means is in condition calling for an up open. circuit through the switch.

With these and other objects in view, my invention with respect to its features which I believe to be novel and patentable will be pointed out in the claims appended hereto. For a betc ter detailed understanding of the invention, and further objects relating to details of economy of my invention, reference is made to the following description and to the accompanying drawing wherein such further objects will definitely .5 appear, and in which Figure l is a front elevation of a switch structure embodying my invention, the cover for the casing being removed, and a freezer system with which the switch is adapted to be used being shown diagrammatically.

Figure 2 is a plan view of the switch structure, and

Figure 3 is a wiring diagram of a system in which my switch structure is installed.

On the accompanying drawing, I have used the reference numeral III to indicate generally a switch housing and I! a cover therefor. Within the switch housing it a supporting bar I3 of insulating material is provided. Terminals I4 and ii are mounted thereon. 5

Connected with the terminal I is a pair of stationary contacts it, while connected with the terminal I5 is a pair of movable contacts H. The contacts i! are carried by a switch arm l8 having an extension l8 which is pivoted to a 10 bracket l9 as indicated at 20.

For normally operating the switch arm. I8, I provide a bellows housing 2 I, a bellows 22 therein, a bell crank 23 operated by the bellows and a link connection 24 for operatively connecting the bell crank 23 with the switch arm. The bellows 22 has an operating pin 25 connected with its head and the pin engages one arm of the bell crank 23. The other arm of the bell crank has a range spring 26 connected therewith to maintain contact between the bell crank and the pin in addition to providing a predetermined range of operation for the switch structure. An adjusting screw 21 is associated with the spring 26 for changing the stress thereof in the usual 25 Y manner to thereby vary the range of operation as desired.

A capillary tube 28 is connected with the bellows housing 2i and terminates in a capillary bulb 29 responsive to the temperature of a freez- 30 or F. The freezer F includes an evaporator coil 30 to which refrigerant is supplied from a compressor system. including a refrigerant compressor motor M, a compressor 0 and a. condenser 3|.

The freezer system further includes a beater motor BM for operating heaters or mixer blades 32. A timer T and a manual switch 33 shunt, each other and control the beater motor BM.

My switch structure further includes a solenoid S, the coil of which is indicated at 3t. The plunger core of the solenoid S is indicated at 35 and is adapted to coact with a Divoted lever 36. The lever 36 is pivoted at 31 to a leg member or bracket 38 of the base 39 of the solenoid S. The bracket 38, together with another bracket l of the base member 38, are secured to a mounting plate 4| which in turn. is mounted on the switch casing 16 as by screws 42. A cover 3, held in place by a screw 44, is provided for the solenoid coil 34. A threaded 5 boss at 45 serves as a connection for electrical conduit or BX cable (not shown).

The lever 36 has a forked end pivoted at 45 to an actuating pin 46. The pin it is preferably formed of an insulating material and extends as through an insulated bushing 41 in the upper wall of the switch casing Ill. The pin is adapted to move the switch arm I8 from its Open p sition shown by dotted lines against the stress of the range spring 26..

A set screw 48 constitutes an adjustable stop for the lever 36. A nut lock 49 is provided to lock the screw against undesired movement after it has been adjusted.

Practical operation In the operation of my switch structure, the refrigerant compressor motor M will be automatically controlled in the usual manner as a result of temperature changes affecting the bulb 29, thus keeping the freezer F at a substantially constant temperature. While the temperature is thus maintained in response to temperature changes, it is nevertheless desirable to additionally energize the motor M whenever the beater motor is operated periodically by the timer T, so as to keep the contents of the freezer in good condition. As the beater or mixer 32 is rotated, it is desirable to supply refrigerant to the evaporator 30 to compensate for any loss of heat as a result of friction between the beater blades and the contents of the freezer. I therefore provide the solenoid S to close the circuit through the main switch, independent of its actuation as a result of temperature affecting the capillary bulb 29. y

In a freezer system including a refrigerant compressor motor and a beater motor, certain problems arise, one of which is the inefiicient operation at starting if both the beater motor and the refrigerant compressor motor are thrown on the line at the same time. Inasmuch as solenoids require a certain percentage of full line voltage before they will attract their plungers, the use of a solenoid in this installation is very desirable,

While the beater motor is coming up to speed, it will require more current than under normal running conditions, and therefore during the starting period it reduces the line voltage. The so lenoid S can be designed so that it will not be able to attract its plunger 35 until the line voltage has come up to the neighborhood of or volts in a llO-volt system. By the time such voltage is attained, the beater motor has passed from its starting cycle into its running cycle and therefore there is approximately full line voltage available for the refrigerant compressor motor M. Accordingly, when the solenoid effects closure of the main switch arm l8, the motor M can come up to speed much more quickly and efliciently than if the beater motor were at the same time passing through its starting cycle and therefore requiring heavy current. Thus the available current for starting each motor is more nearly normal line voltage than in a system where the timer T operates both motors M and BM directly. In that case, the efficiency of both motors during the starting period is greatly reduced and considerable trouble is experienced, particularly with motors which require a high percentage of normal line voltage for efficient starting and running operation.

I have illustrated and described one embodiment of my switch structure which I have found very satisfactory as an installation in a freezer system of the kind disclosed. I have not attempted to illustrate or describe certain adaptations or modifications which I contemplate, or the various uses and adjustments possible, as it is believed that the foregoing specification will enable those skilled in the art to which this invention appertains to embody or adapt such improvements as may be desired, without departing from the scope of the invention as set forth in the appended claims.

Having thus described my invention, I now claim and desire to secure by Letters Patent of the United States:

1. A switch structure comprising a refrigerant compressormotor switch normally responsive to the temperature of a freezer, a solenoid operable upon energization to close said switch independent of its response to the temperature of the freezer, a timer controlled freezer mixer motor, a timer therefor, circuit connections with said timer .for energizing said solenoid and said freezer mixer motor simultaneously, and a manual switch adjacent said freezer and shunting said timer.

2. In a switch structure, a refrigerant compressor motor switch normally responsive to the temperature of a freezer, a solenoid operable upon energization to close said switch independent of its response to the temperature of the freezer, a timer controlled freezer mixer motor, a timer therefor, and circuit connections with said timer for energizing said solenoid and said freezer mixer motor simultaneously.

3. A switch structure comprising a refrigerant compressor motor switch forcontrolling a refrigerant compressor motor and thereby normally maintaining a freezer at a predetermined temperature, means operable only upon energization thereof with current exceeding a predetermined percentage of line voltage to close said switch independent of its normal response, a freezer mixer motor, a timer for controlling said last motor, and circuit connections with said timer for energizing said means and said freezer mixer motor simultaneously.

4. An automatic control device for a refrigerant compressor and normally responsive to the temperature of a freezer, a solenoid operable upon energization to cause said control device to render the refrigerant compressor operative independent of response to the temperature of the freezer, a timer controlled freezer mixer device, a timer therefor, and circuit connections for energizing said solenoid from said timer simultaneously with operation of said freezer mixer device.

5. An automatic control device for a freezer system comprising a switch connected with a refrigerant compressor motor to normally maintain the freezer at a predetermined temperature, the freezer including a mixer and a timer for controlling said mixer to periodically cause operation thereof, a solenoid associated with said switch structure to close the circuit therethrough upon energization of said solenoid, and connections between said solenoid and said timer to effect such energization when the timer operates the mixer.

6. A switch structure for controlling a freezer system comprising a switch connected with a refrigerant compressor motor to normally maintain a freezer at a predetermined temperature, the freezer including a mixer, a timer for con: trolling said mixer to periodically cause operation thereof, manual means to also control said mixer, and a solenoid associated with said switch structure to close the circuit therethrough upon energization of said solenoid, said solenoid being controlled either by said timer or by said manual means.

7. A switch structure for controlling a freezer :ystem comprising a. switch connected with a refrigerant compressor motor to normally mainain a freezer at a predetermined temperature, he freezer including a. mixer, a timer for conrolling said mixer to periodically cause operaion thereof, and a solenoid associated with said :witch structure to close the circuit therethrough ipon energization of said solenoid, said solenoid ieing controlled by said timer.

'8. A switch structure comprising means for iutomatically controlling a refrigerant compres- :or motor of a freezer system having a beater motor and a timer for operating said beater moor periodically, a solenoid mounted on said switch structure and. operable to close the switch thereof when the solenoid is energized, said solenoid being energized simultaneously with said beater motor.

9. A switch structure for automatically controlling a refrigerant compressor motor of a freezer system having a beater motor mixer and a switch for operating said beater motor, a solenoid mounted on said switch structure and operable to efiect flow of current therethrough when the solenoid is energized, said solenoid being energized simultaneously with said mixer switch.

BURTON E. SHAW.

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