US2230612A - Electric control device - Google Patents

Description

e. w. CRISE ET AL 2,230,612

Feb. 4, 1941.

ELECTRIC CONTROL DEVICE Filed March 28, 1936 2 Sheets-Sheet 1 1 fifi I 2 /1 3nvntors 9 I G. w. CRISE a-r AL 2,230,612

ELECTRIC CONTROL DEVICE" 1 Filed March 2a, 1956 2 sa as-sheet 2 3maentors Patented Feb. '4, 1941 notation of Ohio I 2 ,230,612 UNITED STATES PATENT OFFICE 'mc'rmc conmor. nnvlca George W. Crise and Wilford P. (Jrlse, Mount Vernon, Ohio, assignorsto Crise Electric Manm. facturing Company, Mount Vernon, Ohio, a cor- Application March 28, 1936, Serial No. 71,410

40mm. (c1. 172-278.)

od of operating the same filed January 19, 1933,

' 5 'Serial Number 652,528.

The principalobject of our present invention is to provide improved means and method of temperature regulation for furnaces, valves, doors or dampers, stokers or the like in combination with 1 our improvedsingle phase alternating current motor reversibleby making or breaking'a single contact thermostat andhaving split poles with opposing shading screens. This application is a continuation-in-part of our application Ser. No. 652,528, filed January 19, 1933, now Patent No. 2,134,685 issued November 1, 1938.

Another object of our invention is to make use of our single phase induction motor preferably characterized by the fact that so long as the field is energized, it will continue to rotate substantially constantlyeither in one direction or the other. This being accomplished by providing opposing shading screens mounted upon the pole pieces of the motor, one of which is a-permanent- 25 1y short-circuited screen and the other being a wound screen with the circuit thereof extending remotely from the motor and provided with a single contact thermostat switch arranged to make and break the circuit thereof. In this manner when the thermostat switch is open the motor will rotate in one direction-under the influence of the permanent shading screens and when the single contact thermostat switch makes contact, thereby energizing the screens of larger shading capacity, the motor will immediately reverse its direction of rotation against the shading effect of the permanently short-circuited v screen of lesser shading capacity. 40 The larger shading screen being of suflicent shading capacity to reverse the direction of the magnetic shifting through the pole pieces and to provide for the desired speed in the opposite di- 'rection. Therefore, one object of the present invention is to do away with temperature differential such as would exist if two reversing windings were connected to a double circuit thermostat of the so-called open-contact type.

The foregoing and various other objects, the

combination of elements and advantages of .the

invention and method of operation will be apparent from the following detailed description of the preferred embodiment thereof, and will be more particularly pointed out in the claims appended hereto.

In the drawings, wherein like symbols refer to like parts, Fig. l is a front view of the motor in-' cluding the thermostat and furnace. Fig. 2 is a sectional View of motor shown in Fig. 1. Fig. 3 is a view of the preferred gear arrangement used in our motor. Fig. 4 is'a front view and Fig. 5 a

side view of the thermostat used in Fig. 1. Figs. 6 and 7 are enlarged views of the safety members used in connection with Fig. 1, and Figs. 8 and 9 illustrate modifications.

..the center drive shaft bearing' H carrying the final drive gear I2. The said bearings are placed to receive the shafts of the'concentrically arranged gears and pinions I 4 to I! assemblies as shown. There is thus formed a continuous speed reduction gear train from the armature assembly 3 'to the final drive shaft! l3 which carries the final drive gear I2 and sprocket wheel 2|. It will be observed that by adding or omitting gears and adjusting the final drive gear l2 endwise to engage the pinion of the last of the series of the concentrically arranged gears, a variety of gear the gears l8, l9 and 20, Fig. 3, are onfitted from the construction as embodied in Fig. 1.

. end, it'would engage final drive gear l2, then by omitting gear I, a gear shifting means would be provided which could be utilized by merely sliding gear l2 endwise to alternately engage the pinion of gear 6 and the new pinion added to gear assembly 5.

In motor I, the character 22 is the field member which is energized by primary coil 23 that in turn causes a magnetic flux to thread the armature 3 through the split pole projections 24, 25, 26 and 21. On the diagonally opposite pole sections 24-25 there are provided permanent shading coils or screens 28-29 that cause magnetic ratios may be obtained. It will be observed that shifting and a resultant counterclockwise rotation of the armature 3 by the conventional shaded pole principle. .On pole sections 26-21 there are wound shading coils or screens 303I respectively of sufiiciently. larger shading capacity to magnetically reverse the direction of shifting through the fixed screens 28--29 and in opposition to their shading effect thereby causing thearmature to reverse and turn in a clockwise direction when the said wound shading coils 303l are made effective by closing their circuit through the leads 32 and 33 by means of the single contact thermostat switch 34. v

No unshaded pole sections are provided in the spaces between pole sections 24 and 26 or between pole sections 25 and 2i, thereby compelling ail magnetic shifting to thread both the permanent it, the motor armature 3 will operate under the.

sole influence of the fixed screens 2829 turning the sprocket wheel .2I clockwise, lifting draft door 36 and closing check 31 thereby increasing the fire and heat produced by the furnace 35. As soon as the temperature surrounding the thermostat 34 has reached a suflicient level to cause it to remake contact and close the circuit of wound screen leads 3233 the motor armature 3 will reverse due to reverse phase splitting through the pole projections 24, 25, 26 and 21 under the predominating shading influence of the wound screens 303| thereby closing the draft door 36 and opening check damper 31.

Stopping pin 39 on final drive gear [2 is so located as to interfere with the stopping pin 40 carried as a; part of the driving gear I when the sprocket wheel 2| has rotated through the desired range of travel in either direction, thereby'limiting the opening of the draft doors 36' and 31. By placing these stopping pin in various positions and invarious combinations of gears a desired range of travel may'be secured.

A particular advantage of this arrangement lies in the fact that the stopping force is applied not on the final drive gear I2 but further up the gear train as per the present illustration between gears l6 and pinion of gearassembly 6 where the torque and consequent strains are greatly reduced. The action between the two pins 33 and 40 is one in which one pin overtakes the other and by gentle pressure produces in effect, a

second and much higher gear ratio between Sear assembly I and gear [2, thereby causing gear l2 to stall under the opposing influence of the slow moving pinion of. gear assembly I with which it is in mesh. In this manner, since both stopping pins 39 and 40 rotate in the same direction at the same time, but at different rate of speeds, no matter how fast the speeds of travel,when the pins meet the motor is stalled with much less strains between said pins than would be the case if the pins moved in opposite directions.

Numeral 42 designates-a safety device (shown more in detail in Fig. 6) which may be used to close the draft door 36 in case the furnace 36 should become overheated due to failure of other regulating equipment. It comprises the U- V shaped bimetallic frame 42 as shown to which is hinged the pin 43 at its lower end 44 and to which pin is attached the short chain linkage 45 that in turn holds the slack out of the drive chain 33. It will be obvious that since the upper 'end of pin 43 is held in place by passing through an opening 4| in the upperend of the bimetallic frame 42 (for convenience the opening 4| could be cut through the side of the bimetal 42 to form a. notch for reclosing the pin 43), that when thetemperature of the furnace reaches a dangerously high predetermined temperature the frame member 42 will spread open, thereby releasing pin ,43 and closing the draft door 36.

In Fig. 6 we have shown the safety device arranged-toclose a valve 46 which may; be used to supply fuel to the furnace 45. Of course, such water or the like and any suitable type of regulating elementsmay be used and operated in like manner. .43 shows, a turn buckle or the like which serves to increase or decrease the length of the pin to cause the release of the same at a different selectable temperature. r

'- In Fig. 'Iwe have shown a. modification of the device shown in Fig. 6, whereby it will reset itself whenever the load is taken off the chain linkage 45. For example, if the device shown in Fig. 7

is used in Fig. 1 it would relatch whenever the chain becomes slackened by sufficient counterclockwise rotation of sprocket wheel 2|.- The spring 41 should be of sumcient strength. to relatch the pin 43 under-the slight resistance of the latch member 43 when the chain 45 is slack, however, latch 48 is so placed under the lower arm of frame member 42 that it is forced clear of the lower end of pin 43 when the'said frame in Fig. 1 as connected with the leads 32-'33 wherein 5|) is a bakelite frame member carrying the mounting post 5| which is held in place by the acorn nut 52; said mounting post supports. the bimetal element 53 and provides a rotatable calibrating adjustment for said thermostat. 54 is a metallic adjusting arm carrying the contact point so placed .as to engage the contact 66 riveted to the bimetal element 53. An adjusting arm 54 is pivoted around the projecting ring of the bakelite 51, said arm being friction'ally held by the spring loaded insulating washer 63.

It will be obvious that the bimetal coil 53 will carry the contact point 56 into and out of contact with point 55 at times depending upon the temperature of the surrounding air and the setting of the adjusting arm 54, there being the same definite temperature for both opening and closing of the contact for each position of theadiusting arm 54. Because the bimetal element 53 is in the-electrical circuit of the controlled current, due to its light construction, an appreciable amount of heat may be generated by its resistance when used in a low voltage circuit of moderate amperage, this gives rise to two possible eifects: First, if the-bimetal is' so wound 'as to contract when heated, it will break its circuit at a lower room temperature than the temperaturegat which it makes contact due to the internal heat generated when in contact, thereby producing a time lag or temperature differential. Second, if the bimetal is so wound as to contract when cooled, it will break circuit at a lower temperature than that required to bring the points back into contact. This will give rise to an oscillating tendency or negative temperature differential which may be utilized to overcome sticking of contact points and produce more frequent operation of the drafts when a thermostat so designed is used on a heating system.

Fig. 8 shows a modification ofour improved heat regulating system utilizingacpmpensating high limit switch 59 whereby the maximum temperature to which the furnace may rise is influenced by the temperature of the surrounding air. In this instance, the controls are so arranged that the motor opens the draft door 36 when the thermostat circuit is closed, and closes the draft when the circuit is open. The thermostat switch 59 is arranged to open the control circuit when it exceeds a predetermined temperature, therefore. causing the motor to close draft door 36 and open the check damper 31 and throttling the furnace or fire and reducing or attenuating the heat from the same independently of the setting or condition of the room thermostat 34. A

particular advantage of this system lies in its compensating efiect in that it permits the furnace to rise to a higher temperature in zero weather when the air of the basement surrounding the thermostat 59 is relatively colder than it is in mild. weather when less heat is required, this effect being particularly desirable on hot water furnaces where more time is required for heat to get from the furnace to the rooms to be heated. When thermostat 34 is set to about 5 70 F., the thermostat 59 should be set to desired temperature between 150 F. and 300 F., de-

pending on the surrounding atmospheric conditions, ordinarily at about between 200 F. and

Fig. 9 shows an enlarged view of our compensating surface switch 59 in which 60 is the case, 6| the bimetal element carrying the contact point 62 that engages the contact 63 of the adjusting screw 64 to produce the conventional thermostatic effect. 65 designates an adjusting screw to lift one end of the surface switch out of contact with the wall of the furnace 35 to reduce the rate of travel of heat to said surface switch and allow it to be affected by the tem- 1lzigrtsziture of the outside air to any desired ex- It will be obvious that by varying the relative size of the fixed and wound screens, faster operation can be secured for the closing of the draft than for the opening thereof if desired, or

the effect may be reversed.- Furthermore by reversing the positions of the fixed and wound screens or by changing the number of steps of gear reduction, the direction of rotation also,

the speed and torque of sprocket 2| can b varied as desired.

In this manner the motor may be caused to rotate much faster to close a valve or a damper, or close a draft damper and open a check faster when the demand is for less heat as compared to whenthe demand is for more heat. By op-- erating the motor twice as fast in one direction, much fuel can be saved.

The limit switch is attached to the furnace 60 wall by means of the screw 66 and spring 61 which allows for adjustment of the switch to or from the wall of the furnace 35.

The elements disclosed in Figs. 4 to 7, also such as shown in Fig. 9 and at 59 in Fig. 8, 65 together with the description thereof, all relate to thermostat means arranged to cause the damper 36 to'either open or to close under predetermined temperature conditions. Of course, our improvements in this art include means for operating valves, doors, windows, switches or the like including devices and method of operations which may be advantageously used in connection with our improved motors. From the above it will be clear that other modifications are possible without departing from the broad scope and spirit of our invention, and all of the above including means disclosed in this application and the subject matter shown and described with respect to Figs. 1, 2, and 3, are all related to similar subject-matter of invention relative to this art and to the subject matter of our first filed application for patent Serial No. 652,528, filed January 19,1933.

.When desired any or all of the safety devices shown in Figures 1 and 8 may be omitted or for other purposes, the thermostat 34 shown in Figure 9 may be omitted, operating the heating system under the sole control of the compensating" surface limit switch 59.

What we claim is:

1. In an electric power device of the character described, an alternating current motor having an armature and a shading coil adapted to be energized for causing rotation of the armature, a circuit for said coil including a control switch, a train of cooperating gears connected with said armature to be driven thereby, and means for stopping the motor comprising pins projecting from at least two gears of said train and adapted to engage each other after predetermined rotation of the armature.

2. In an electric power device of the character described, a motor having an armature and a main coil adapted to be conti uously energized by alternating current, a shading coil adapted to be energized for causing rotation of the armature, a circuit for the shading coil including a control switch, a train of cooperating gears connected with said armature to be driven thereby, and means for stopping the motor without deenergizing said main coil or opening the shading coil circuit comprising pins projecting from at least two gears ofsaid train and adapted to engage each other after predetermined rotation of the armature.

3. In an electric power device of .the character described, a reversible shaded pole induction motor having a stator with a primary winding thereon, a rotor, and two shading coils respectively tending when energized to cause rotation of the rotor in opposite directions, a shading coil circuit having a switch therein, one of said shading coils being effective upon closing of said switch to exert a sufliciently greater shading effect than the other shading coil to cause rotation of the rotor in the corresponding direction, a train of cooperating gears connected with said armature.

to be driven thereby, and means for stopping the motor without deenergizing said primary winding or opening the shading coil circuit comprising projections on at least two gears of said train adapted to engage each other after predetermined rotation of the armature.

4. An electric power device of the character descrlbed,'comprising an electric motor, a circuit for energizing the motor, a train of gears connecting the motor with a shaft to be driven and including two gears having different rotative speeds, andpins carried by said two gears and located thereon to engage each other after predetermined rotation of the gears to thereby stop the motor while the latter remains energized.

GEORGE W. CRISE. WILFORD P. CRISE.

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