US2175762A - Control apparatus - Google Patents

Description

Oct. 10, 1939. E. c. RANEY 2,175,762

CONTROL APPARATUS Original Filed June 12, 1936 2 Sheets-Sheet 1 28 I H IMSULAV/O'l INVENTOR BY ZA MMWFZZ'JML,

ATTOR NEY Oct. 10, 1939. c RANEY I 2,175,762

CONTROL APPARATUS- Original Filed June 12, 1936 2 Sheets-Sheet 2 INVENTOR mwsih ORNEY Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE CONTROL APPARATUS Estel C. Haney, Columbus, Ohio, als ignor -to Ranco Incorporated. Columbus, Ohio, a corporation of Ohio BClaims.

The present application is a division of my copending application S. N. 84,800 now Patent #2,l33,400, granted October 18, 1938.

My present invention relates to control apparatus and more particularly to thermally actuated tripping devices for controllers and the like.

One of the objects of my invention is to provide a tripping device for controllers, which includes a freely translatable latch, for holding the controller in one position, and a thermally actuated release device for the latch, which device is operable upon the attainment of a predetermined temperature for releasing the latch to effect movement of the controller to another position.

Another object of my invention is to provide a thermal tripping mechanism for a controller, which includes a freely translatable latch, for holding the controller in one position, which thermal tripping mechanism, upon the attainment of a predetermined temperature, releases the controller to assume another position, the device being also provided with manually operable resetting means for causing the thermal mechanism to reengage the controller and to hold the same in the first position, said resetting means only being effective when the thermal mechanism has cooled below said predetermined temperature.

A further object of my invention is to provide athermal switch which includes a freely translatable latch for holding the circuit controlling means in one position and thermal responsive means provided for actuating the latch for causing the circuit controlling means to assume another position.

In carrying out the above object it is a further object to provide a heater for the thermal responsive means disposed in heating relation thereto, said heater being responsive to the amplitude of the current traversing the circuit in which the circuit breaker is included.

Other and further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the present invention is clearly shown.

Fig. 1 is a side view in elevation of a switch with the contacts in closed position;

Fig. 2 is a view, partly in section, of the switch shown in Fig. 1, with the contacts in the open position;

Fig. 3 is a top view of the switch;

Fig. 4 is a sectional view on an enlarged scale of the ratchet and solderpot assembly.

Fig. 5 is a view in elevation of the ratchet p5 assembly shown in P18. 4.

6 is a view in elevation of the ratchet assembly, the view being taken in the direction indicated by the arrow in Fig. 5, and,

Fig. 7 is a schematic wiring diagram of the switch in a motor circuit.

Fig. 1 shows a thermally actuated switch 20. A base 2| fabricated from a dielectric material, is used as a means to attach the switch to an appliance, for example, within the end bell of a motor. A member 23 of pressed metal is positioned on the base 2| by two integral lugs 26' which pass through the base and are clinched over on the opposite side of the base 2|. The member 23 is also provided with an integral connecting lug 21 for electrical connection. A fixed contact 22 of suitable material, such as silver, is mounted, as by riveting, on the support member 23.

A movable member 25 is preferably fabricated from spring material, such as full temper phosphor bronze, which has desirable electrical conducting properties. A contact 24 is mounted, as by riveting, to the movable member 25. The member 25 is so formed as to normally tend to separate the contacts.

The opposite end of the member 25 is connected to the upper side of a U-shaped support plate 23 by lugs 29 which are integral with a plate 28 and pass through apertures 25' in the member 25. The lugs 29 are clinched over to insure a tight mechanical and electrical connection between the support 28 and the member 25.

The opposite, or lower, leg of the U-shaped support member 28 is fixed to the base 2| by integral lugs 30 which pass through the base 2| and are clinched over on the opposite side of the base 2|.

The member 28 also acts as the support for a ratchet 3|, through its associated parts. A hollow bearing post 32 forms the spindle for the ratchet 3|. The post 32 is provided with an outwardly extending flange 33 for connection to the support 28. The flange 33 is attached to the member 23 by integral. lugs 34 clinched over to form a tight engagement.

The ratchet 3| loosely embraces, and can be freely rotatable on the post 32 when not held in place by solder. A substantially circular plate 35 is pressed over, and staked to, the post 32 to prevent displacement of the ratchet 3|, with respect tothe supporting post 32.

To prevent the ratchet 3| from normally being rotatable, a low melting point solder 36 is used to solder the ratchet 3| to the post 32. The composition of this alloy 36 may be varied to obtain any desired fusing point, for example, 200 F.

An engaging means, or dog 31, of dielectric material is employed to provide an actuating link between the ratchet 3| and the member 25. This dog is freely translatable, in that no fixed hearing point is provided. The dog 31 has a single projection 38 on one end thereof to engage with the teeth of the ratchet 3|. The opposite end of the dog 31 is provided with two projections 39 and 42, that form a substantially forked end portion on the dog 31, The point 39 rests on the top of the member 25, as part of the dog passes through an opening 43 in the member 25. The other projection 42 is so disposed as to limit the upward movement of one end of the dog 31 by engaging the underside of the member 23, as

may be seen in Fig. 2: the base 2| being cut away, to form openings therethrough for the various extending parts of the dog 31.

The dog 31 is-drawn normally toward the base 2| by the tension of a spring 48 attached at one end through the hole' 44 in the dog 31, and at the other end to the reset guide member 4| which is fixed to the base 2 I. The spring 40 is so disposed as to supply a horizontal component of force tending to force the dog 31 toward the ratchet 3| as well as provide the aforementioned downward tension. A reset lever 45 of pressed metal is pivotally attached to the dog 31 by a rivet pin 46. The lever 45 is split at its upper end to form a forked portion which engages either side of the dog 31. The opposite end of the lever 45 passes through an aperture 45 in the guide member 4|. This construction is followed to assure alignment of the lever 45and associated parts. The device 20 may be suitably secured to and on the inside of the end bell 80 of the motor 54 and the lever 45 projects through an opening 6| of the bell 60 so as to be accessible from the exterior of the motor for resetting of the tripping device.

It will be noted that when the projection 38 on the dog 31 is set in the teeth of ratchet 3|, the opposite end or projection 39 is bearing down on the spring contact member 25. In this position the spring 40 is tending to draw the dog 31 downwardly, which firmly presses the contacts 22 and 24 together to make an electrical contact. This position may be studied in Fig. 1.

When the projection 38 on the dog 31 has'been displaced from engagement with the teeth of the ratchet 3|, the spring pulls the dog 31 downwardly, until pin 48 rests on the base 2|, in which position the dog 31 pivots on the pin 48 due to the tension of spring 48, and the projection 39 raises, to allow separation of the contacts 22 and 24, as illustrated in Fig. 2.

The projection 42 acts as a bearing point against the member 23 when the dog 31 is being reset. As the reset lever 45 is pressed inwardly the dog 31 pivots on the projection 42, as the projection 38 is raised relative to the base. The projection 38 contacts the teeth of the ratchet 3| but due to the translatable movement of the dog, is capable of slipping past the teeth until the lever 45 has reached its maximum inward movement. During this resetting operation the contacts 23 and 24 are not in engagement as the dog 31 is pivoting on its projection 42. As soon as the pressure is released on the lever 45, spring 40 supplies a downward tension to engage projection 38 with the teeth of ratchet 3| and also to close the contacts, since projection 39 of the dog 31 is now bearing down on the contact member 25.

From the foregoing it will be noted that it is impossible to make contact through the device 20 by pressing in on the lever 45. In a like manner if the ratchet 3| is not flxed in position, that is, if the solder is fused, it is also impossible to close the switch 20.

In the present embodimentrtwo heating coils 41 and 48 of any desired resistant material are disposed within the bearing post 32, in heattransferring relationship to the solder 36. One end of each of the coils 41 and 48 is spot-welded or otherwise attached to the support member 28. These coils 41 and 48 supply radiant heat when electrically energized by the passage of a current therethrough.

When either or both of these resistances supply sufficient heat to bring the temperature of the ratchet 3| and solder 38, to say, 200 F., the solder 38 will fuse and the ratchet 3| will be capable of rotation on the post 32, In the set position of the switch, spring 40 and dog 31 are constantly supplying a downward pull, or turning torque, on the ratchet 3|. Therefore, when the solder 36 fuses, the ratchet 3| rotates in a clockwise direction and allows the dog 32 to come to the position as in Fig. 2. It is apparent that by varying the resistance of the coils that the time period for operation may be altered to give any desired time cycle.

The same effect may be obtained when the switch 20 is mounted on a motor or other type of energy translating device. If the motor frame reaches a predetermined temperature of say 200 F. due to a heavy load, a scraping armature, etc., the switch 20 will be heated conductiveiy by the motor frame, to fuse the solder 38, which will allow rotation of the ratchet 3| to separate the contacts 22 and 24.

The points 22 and 24 are incapable of being reset after operation until the solder 38 has rehardened. At this time, the reset lever 45 may be pressed inwardly to engage the dog projection 38 with the ratchet 3|, thus re-closing the contacts 22 and 24.

This particular feature of construction is a safety factor, for it will be noted that even when the lever 45 is held in the set position, that the contacts cannot be closed until the ratchet 3| is fixed in position. This assures that the motor 54 has cooled to a safe temperature before operation can be resumed.

Fig. '7 illustrates a schematic wiring diagram, showing one of the many circuits in which the switch 20 may be advantageously utilized. A single phase A.C. motor is generally indicated at 54, having a starting winding 53 and a running winding 52. Current is supplied by the power lines 50 and Line 5| is connected to both the starting winding 53 and the running winding 52. The other side of the line may be traced from wire 50, to contacts 22 and 24 of switch 20, through member 25, then splitting through heating coils 41 and 48. From the coil 48, the current goes through wire 51 to the field running winding 52, to complete the circuit. The current through coil 41 traverses wire 55, condenser 56, centrifugal switch 59, and wire 58 to complete the starting circuit. When both the running and starting winding circuits are energized, the motor starts to rotate. As the motor 54 gains speed, the starting winding 53 is no longer required and a usual type of centrifugal switch 59 opens the circuit, through the winding 53 and the heating coil 41.

In this particular embodiment, the resistance 41, which is placed in' series with the starting winding, is so balanced with the resistance 48 that the two resistances 41 and 48 radiate sumcient heat to fuse the solder 30 in a predetermined time period. -This will protect the winding if the motor should not start, or should not gain sufficient speed to cut the winding II out of the circuit. 7

The resistance 0 in series with the running winding, is balanced to supply sumcient heat to keep the switch at a temperature of say, F., (normal running temperature) during normal operation. Thus, if an overload current should pass through the coil 48 to cause a rise in temperature, the coil is capable of quickly translating a corresponding rise in temperature to the solder, to operate the switch 20 and protect the motor 54.

By maintaining the switch 20 at a temperature slightly below the fusing point of the solder, it is possible to eliminate operation of the switch, due to transient overloads of any type that are not harmful to the motor. I In other words, the switch 20 will only operate on persistent overload conditions that would cause damage to the motor if allowed to continue.

The motor temperature also aids in maintaining the switch at a given temperature, thus if too heavy a load is impressed on the motor that causes the motor to gradually increase in temperature, the switch 20 will likewise increase in temperature, due to conduction. This maintains the switch at practically the same temperature as the motor, so that operation, free from a time lag, is obtained on overheating of the motor. Thus the switch is sensitive to the temperature of the motor, the temperature of the heater, or a combination of the two sources of heat, to act as a protective device, under any type of overload condition. I

From the foregoing it will be noted that I have provided a safety cut-out switch to completely protect the motor against injury due to any type of overload or open circuited windings. The resistance coils 41, and 48 may be varied in heating effect to obtain any desired results. For example, only one coil may be used or both coils may be in the circuit continuously. In the latter case, the resistance of the coilsshould be calculated so that their combined heat output under normal conditions is insuflicient to fuse the solder, but that a rise in temperature, in either coil due to overload current, etc., or an abnormally high temperature of the motor will supply the added heat necessary to operate the device.

While the .present embodiment includes two heating coils, it is apparent that any number of coils can be utilized according to the particular installation contemplated. The trip-free construction of the device makes it applicable in controller installations wherein the heater iseliminated entirely, and where the device is in direct heat transfer relation to the energy translating device.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adapted, all coming within the scope of the claims which follow:

I claim:

1. A control switch having fixed and movable contacts, a ratchet wheel rotatably mounted on a hollow pinion and held in a fixed position by solder, elastic engaging means connecting the ratchet to the movable contact to normally maintain the contact in a closed position, said means causing constant turning torque on the ratchet, and a plurality of heaters disposed within the pinion, said heaters being responsive to current flowing through the switch.

2. A thermally responsive tripping device comprising relatively fixed and movable members, said movable member normally tending to separate from the fixed member, a ratchet capable of rotation disposed on a hollow pinion and fused in place by solder, a translatable dog, bearing downwardly on the ratchet at one end and on the movable member at the other, said dog being normally engaged to close the movable member, heating means disposed within said hollow pinion capable of fusing said solder for causing rotation of the ratchet and displacement of the dog.

3. A thermal responsive circuit breaker comprising, flxed and movable contact members, said movable contact member normally tending to separate from the fixed contact element; a ratchet, capable of rotation, disposed on a hollow pinion and fused in place by solder; a translatable dog bearing downwardly on the ratchet on one end thereof and on the movable contact member on the other end thereof, said dogbeing normally engaged with the ratchet for causing said movable contact member to engage said fixed contact member; and heating means disposed in said hollow pinion and capable of fusing said solder for causing rotation of the ratchet and displacement of the dog.

4. A thermal responsive circuit breaker comprising, fixed and movable contact members, said movable contact member normally tending to separate from the fixed contact element; a ratchet, capable of rotation, disposed to a hollow pinion and fused in place by solder; a translatable dog bearing downwardly on the ratchet on one end thereof and on the movable contact member on the other end thereof, said dog being normally engaged with the ratchet for causing said movable contact member to engage said fixed contact member; heating means disposed in said hollow pinion and capable of using said solder for causing rotation of the ratchet and displacement of the dog; and means for resetting the dog in engagement with the ratchet for causing said fixed and movable contact members to be reengaged, said last means being effective only when said solder is solidified.

5. In a switch, a base having stationary and movable parts thereon, said parts including a movable contact and a stationary contact, a current operated thermal release element, a lever having one end thereof pivoted on the element and movable when the element is released, the other end of said lever being furcated, a spring normally urging one of the tines of said lever onto the movable contact for holding the latter in a certain position with respect to the stationary contact and for causing release of the movable contact to another position when the thermal element is released, the other tine of the lever being disposed to engage with and pivot about a stationary part carried by the base when the lever is in said released position, and means for moving the lever to cause the same to pivot on the latter mentioned tine.

6. In a switch, a base having stationary and movable parts thereon, said parts including a movable contact member and a stationary contact member, a current operated thermal release element, a lever having one end thereof pivoted on the element and movable when the element is released, the other end of said lever being furcated and said contact members being disposed between the tines thereof, a spring normally.

urging the lever in a direction to cause one of the tines of the lever to move the movable contact member against the stationary contact member and for moving the lever in another direction to release the movable contact member to an open position when the thermal element is released,

CERTIFICATE OF Patent N0. 2,175,762.

and means for moving the lever to engage the other tine with the stationary contact member and for pivoting the lever about the latter mentioned tine to move the said one end of the lever into engagement with the release element.

ESTEL C. RANEY.

CORRECTION.

October '10, 1959.

ESTEL C. RANEY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, sec- 0nd column, line 14.2, claim 1.1., for the word "using" read --fusing-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this l th day of June, A. D. 19119.. I

(Seal) Henry Van Arsdale, Acting Commissioner of Patents.

Images