US2200845A - Overload cutout switch - Google Patents

Description

May 14, l1940.

A. L.. JUDsoN 2,200,845

OVERLOAD CUTOUT SWITCH Filed March 17, 1938 Figfw M9067@ IIIIIHJIQO gez?) F1o 'Iz 'lz 7% y. 'I' @IFIF am @IFIF f @N @IHF i! zum @IFIF 72am 53 :I 7* rII 55 1I 53 'IIl 53 62 'lnocntor (Ittormg Patented May 14, 1940 UNITED STATES PATENT GFFICE OVERLOAD CUTQUT SWITCH 'Application March 17, 1938, Serial No. 196,448

12 Claims.

This invention relates to switching mechanisms in general and more particularly to an overload cutout switch.

An object of this invention is to provide a novel mechanism for resetting an overload cutout switch which prevents closing of the contacts thereof during the resetting operation.

A further object of this invention is to provide a novel arrangement wherein the resetting mechanism for the overload cutout also forms a means for manually operating the switch.

Still another object of this invention is to provide a fool-proof arrangement wherein it is impossible to block the overload cutout switch in a closed position so that the overload cutout switch will at all times be responsive to overload conditions.

Other objects and advantages will become apparent to those skilled in the art upon reference to the accompanying specication, claims, and

drawing; in which Figure 1 is an elevational view of the switching mechanism of this invention.

Figure 2 is an elevational view looking from the right in Figure 1,

Figure 3 is a view similar to Figure 1 with certain of the parts omitted,

Figure 4 is a. sectional view of a portion of the apparatus of Figures 1, 2, and 3,

Figure 5 is an exploded view showing the positions of the various parts of the switching mechanism when the switching mechanism is manually positioned in an off position,

Figure 6 is an exploded view similar to Figure 5 but showing the parts in an on position with no overload condition occurring,

Figure '7 is an exploded view similar to Figures 5 and 6 showing the parts in `a position repre-.

senting the switch in an on position after the occurrence of an overload condition, and

Figure 8 is an exploded view similar to Figures 5, 6, and 7 showing the switch blocked in an on position after the occurrence of an overload condition.

'Ihe overload switching mechanism of this invention may find particular utility in the control arrangement shown and described in application Serial No. 196,447, iiled by Albert L. Judson and Carl G. Kronmiller on March 17, 1938.

Referring now to Figures 1, 2, and 3 the switching mechanism is shown to comprise a casing I3 preferably made oi insulating material and having a top wall II, side walls i2 and I3, a bottom wall I4, and a back wall I5., If desired the casing may be formed of a single integral unit as (Cl. 20G-116) shown. The side walls I2 and I3 are formed with ears I6 through which screws I1 extend for securing the casing to a base I 6.

A conductor bracket 20 is suitably secured to the casing I0 by rivet 2I extending through an 5 opening 22 in a pad 23 carried by the casing I0. The conductor bracket may be provided with a terminal 24 and also with a screw 25 to which one end of a heater element 26 is secured. The other end of the heater element 26 is secured by 10 a screw 21 to another bracket having an upstanding lug 28, a conductor bar 29, and lugs 30 to which is secured a terminal 3|. The terminals 24 and 3| may be included in series in a motor circuit such as a compressor circuit and the cur- 15 rent iiowing through this circuit will pass through the heater 26 so that the heater 26 is heated in accordance with the current conditions in the circuit.

A bimetallic element 33 is located adjacent the 20 heater element 26 so as to be aiected by the heat given 01T by the heater element. The bimetallic element 33 is secured to a bracket 34 by means of rivets 35, the bracket 34 having an arm 36 extending upwardly adjacent the side wall I3. 25 The upper end of the arm 36 is provided with an eccentrically headed screw 31 which abuts against a pad 38 carried by the side wall I3. 'I'he arm 36 of the bracket 34 is also provided with a lug 39. A spring member 40 pivots the bracket `3() 34 to the side walls I2 and I3 of the casing and extends upwardly between the lug 39 and the pad 36 to hold the eccentrically headed scre'w 31 in engagement with the pad 38. By rotating the eccentrically headed screw 31 the bracket 34 is 35 rotated and hence the bimetallic element 33 is rotated inwardly or outwardly with respect to the casing I. The construction thus far described provides a simple means for adjusting the position of the bimetallic element 33 as well as holding the parts in an assembled relation.

Extending through the casing I6 from one side wall I3 to the other side wall I2 is a pivot pin 42. Mounted on this pivot pin between-the Walls I2 and I3 is a first member 43 having an indicat- 45 ing surface 44. The member 43 is hollowed out at 45 as shown in Figure 4 and located in the hallowed out portion and also mounted on the shaft 42 is a second member 46. This second member 46 is provided with a tripping lug 41, a 50 resetting lug 48, and a contact operating lug 49 as is clearly shown in Figure 4. The iirst member 43 is provided with an elongated slot 56, the function of which will be pointed out more fully hereafter. 55

the second member.

Also mounted on the pivot pin adjacent 'to the iirst member i3 is a third member having an actuating handle 53. The third member iii. carries a pin t which extends through the slot 5i) of the iirst member and which is adapted at certain times to engage th'e actuating lug of The third member t2 is provided with opposed abutment surfaces 55 and 56 which are adapted to engage a lug 5l iorrned on the inner side of the pad 23. The lug di limits the amount of rotation of the third member 52 about the pivot pin 12. The third member 52 is provided with a contact operating lug and is also provided with a V notch A torsion spring di! about the pivot pin i2 is interposed between the rst member 43 and the third member 52, this spring acting to rotate the two members in the opposite direction. As viewed in Figure 5 this spring operates to rotate the first member :i3 in a clockwise direction and the third member k'52 in a counter-clockwise direction.

A resilient contact arm E2 is suitably carried by the back Wall l5 of the casing iii and extends downwardly through the base iii to 'form a terminal 63. A second resilient contact arm at also suitably secured to the back wall i5 of the casing it extends downwardly through the base lli to 'form a terminal Si. The contact arm t2 carries a contact t5 and thecontact arm li carries a contact Sii, these contacts engaging each other under certain conditions. The contact arm Sil is normally in a relatively vertical position and the contact arm 62 is biased by its own resiliency to move normally the contact t5 out oi engagement with the Contact BS. be of the corrugated type, is shown at til in Figure 2 and this spring extends between the if notch 59 of the third member t2 and a suitable notch 4iorn'ied in the back wall i5 oi the casing it. vThis spring operates as a detent or overcenter device for holding the third member 52 in either of its extreme positions. i

A suitable cover 10 for enclosing the structure thus far described may be provided and located in this cover are two openings 'ii and "Eine opening 'H receives the handle 53 of the third member and the opening 'i2 exposes the indicating surface M of the first member Formed on the indicating surface it of the first member di! is an indicator 'i3 which moves into alignment with the opening 'l2 in the cover iii whenever the switching mechanism is tripped openopon the occurrence of an overload condition.

Referring now to the exploded views oi Figures 5, 6, '7, and 8 the mode of operation oi this switching mechanism is disclosed. Each of these figures set forth the positions oi the parts with respect to the openings in the casing it, the positions of the contacts ii: and and the bimetallic element 33 and the positions oi the iirstsecond, and third members fit, and 55E, respec tively. Figure 5 illustrates the bimetailic element 35i engaging the tripping lug M oi the second member iii to hold the contact 55 in a position where it would normally be engaged by the contact Sii. However, the handle of the third member 52 is moved to the ofi position and is held in this on" position by the corrugated overcenter spring till. 'When the member is in the off position the contact operating lug thereof engages the contact arm iii to move the contact Sii vto the right out of engagement with the contact B5. Hence with the parts in the position shown in Figure 5 the contacts t5 and are v gaging the tripping lug ill of the A spring, which may accosta separated and the switch is in the ofi or open position.

In Figure 6 the thermostatic element i is ensecond member [it and hence the contact arm Sii and contact are held in a closed position. The handle 53 however is moved to the on position and is held in the on position by the corrugated over-center spring Si. 'With the third member 52 in this position the contact operating lug St is moved away from the contact member G so that the contact 5B is in engagement with the contact S5 and the switch is in an "on position.

if now an overload condition in the motor circuit should occur which results in excessive heating of the heater element 26 the bimetallic element 33 is exed to the right as shown in Figure '1. When this occurs the bimetallic element moves out from under the tripping lug il and the spring @t rotates the first member i3 and hence the second member 41 in a clockwise dif rectlon. When this occurs the contact operating lug i9 of the second member 5S moves away 'from the contact arm Si and due to the resiliencyY of the contact arm the contact 35 is moved out of engagement with the contact 5t. Hence even though the handle 53 of the third member 52 is in the on position and an overload con dition occurs, the contact ifi is moved out oi engagement with the contact 56. The occurrence of an overload condition is indicated by the mark i3 oi the indicating surface M being exposed in opening T.

When the overload condition no longer exists and the thermostatlc element 33 cools down to move towards the left the switching mechanism may be reset by moving the handle 53 of the third member 52 to the "06 position. When the handle 53 is thus moved to the off position the contact operating lug 5B of the third member 52 engages the contact arm 55 to move the contact to the right and the first and second members 53 and t are moved in a counter-clockwise direction by the pin M of the third member 52 to allow the bimetallic element 33 to engage the tripping abutment ti. The parts then assume the position shown in Figure 5 and when the handle is then moved to the on position as shown in Figure 6 the contact 6B engages the contact tt as shown in Figure 6 and the parts are in position for further operation. From the above it is seen that the contacts E5 and 35 may be manually opened or closed and that they may be opened upon the occurrence of an overload condition. The parte are also arranged so that when the switching mechanism is being reset following the occurrence of an overload condition, the contacts are maintained apart until the switching mechanism is subsequently returned to the "on position.

It is found that in previous overload cut-out arrangements that persons not familiar with the operation ci the same Willi attempt to block the overload cut-out switching mechanism in the on position to prevent the same from cutting out upon the occurrence oi overload conditions. Thi.' reason oi the construction of the overload cutnout switching mechanism oi this invention blocking oi the switching mechanism in the on position to prevent the same from cutting out upon the occurrence of an overload condition is impossible. out'iined above in connection with Figures ai, d, and 7 the switching mechanism will open upon the occurrence of on overload condition even though the handle 52, oi the third member is held in the "on position. Even if the first member is blocked in the on position as by a match or other device the switching mechanism will be opened upon the occurrence of an overload cut-outcondition.

Referring now to Figure 8 the first member or indicating member is shown blocked in an "on position by a match 15. If an overload condition should occur to move the bimetallic element 33 to the right the tripping lug 41 will be disengaged and the resiliency of the contact member 62 will rotate the second member 46 in a clockwise direction to allow movement of the contact 65 out of engagement with the contact 66, hence it is impossible to prevent the contacts 65 and 66 from separating upon the occurrence of an overload condition.

Although for purposes of illustration one form of this invention has been disclosed other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and therefore this invention is to be limited only by the scope of the appended claims and prior art.

I claim as my invention:

l. In combination, first and second contacts, means for biasing the first contact away from the second contact, trip means for holding the first contact in engagement with the second contact when set and for allowing the contacts to separate when tripped, manual means for resetting the trip means including means for maintaining the contacts separated until the trip means is reset, and means associated with said manual means for holding it in a position tomaintain the second contact out of engagement with the first contact.

2. In combination, first and second contacts, means .for biasing the first contact away from the second contact, trip means for holding the -rst contact in engagement with the second contact when set and for allowing the contacts to separate when tripped, manual means for resetting the trip means including means for holding the second contact out of engagement with the first contact until the trip means is reset, and spring means operative upon said manual means for holding the second contact out of engagement with the first contact.

3. In combination, rst and second contacts, means for biasing the rst contact away from the second contact, trip means for holding the iirst contact in engagement with the second contact when set and for allowing the contacts to separate when tripped, manual means movable from a first position to a second position for resetting the trip means and for holding the second contact out of engagement with the first contact until the trip means is reset, and detent means for holding the manual means in the second position for maintaining the second contact out of engagement with the rst contact.

4. In combination, rst and second contacts, means for biasing the iirst contact away from the second contact, an arm movable to a first position to hold the :first contact in engagement with the second contact and movable to a second position to allow the first contact to separate from the second contact, means for normally holding the arm in the rst position, manually operated means movable from a first position to a second position for moving the second contact away from the iirst contact and detent means for holding the manually operated means in the second position.

5. In combination, first and second contacts,

means for biasing the first contact away from the second contact, an arm movable to a iirst position to hold the rst contact in engagement with the second contact and movable to a second position to allow the first contact to separate from the second contact, means for normally holding the arm in rst position but operative to allow the arm to move to the second position upon the occurrence of a predetermined condition, manually operated means vmovable from a firstI position to a second position to move the arm from the second position to the first position and to move the second contact away from the iirst contact, and detent means for holding the manually operated means in either of its positions.

6. In combination, rst and second contacts, means for biasing the first contact away from the second contact, an arm movable to a first position to hold the first contact in engagement with the second contact and movable to a second position to allow the first contact to separate from the second contact, means for normally holding the arm in the first position but operative to allow the arm to move to the second position upon the occurrence of a predetermined condition, manually operated means movable from a first position to a second position to move the arm from the second position to the first position and to move the second contact away from the first contact, and over-center spring means for maintaining the manually operated means in either the iirst or second positions.

7. In combination, rst and second contacts, means for biasing the rst contact away from the second contact, a movable member movable to a first position to hold the first contact in engagement with the second contact and movable to a second position to allow the iirst contact to separate from the second contact, an indicator'member having a one way connection with the movable member and urged from a first position toward a second position for urging the movable member towards the second position, means for normally holding the movable member and the indicator member in their nrst positions but operative to allow the movable member and the indicator member to move to their second positions upon the occurrence of a predetermined condition, the arrangement beingsuch that even though the indicator member is held in the iirst position, the movable member can move to the second position to allow the first contact to separate from the second contact.

8. In combination, first and second contacts, means for biasing the first contact away from the second contact, a movable member movable to a first position to hold the first contact in engagement with the second contact and movable to a second position to allow the rst contact to separate from the second contact, an indicator member having a one way connection with the movable member and urged from a first position toward a second position for urging the movable member toward the second position, means f or normally holding the movable member and the indicator member in their first positions but operative to allow the movable member and the indicator member to move to their second positions upon the occurrence of a predetermined condition, the arrangement being such that even though the indicator member is held in the fust position, the movable member can move to the second position to allow the first contact to separate from the second contact, manually operated means movable from a first position to a second position to move the movable member and the indicator member from their second positions to their first positions.

9. In combination, first and second contacts. means for biasing the iirst contact away from the second contact, a movable member movable to a first position to hold the first contact in engagement with the second contact and movable to a second position to allow the rst contact to separate from the second contact, an indicator member having a one way connection with the movable member and urged from a first position toward a second position for urging the movable member toward the second position, means for normally holding the movable member and the indicator member in their first positions but operative to allow the movable member and the indicator member to move tov their second positions upon the occurrence of a predetermined condition, the arrangement being such that even though the indicator member is held in the first position, the movable member can move to the second position to allow the first contact to separate from the second contact, manually operated means movable from a first position to a second position to separate the contacts.

10. In combination, first and second contacts, means for biasing the iirst contact' away from the second contact, a movable member movable to a first position to hold the first contact in engagement with the second contact and movable to a second position to allow the iirst contact to separate from the second contact, an indicator member having a one way connection with the movable member 'and urged from a first position toward a second position for urging the movable member toward the second position, means for normally holding the movable member and the indicator member in their first positions but operative to allow the movable member and the indicator member to move to their second positions upon the occurrence of a predetermined condition, the arrangement being such that even though the indicator member is held in the rst position, the movable member can move to the second position to allow the first contact to separate from the second contact, manually operated means movable from a' first position to a second position to move the movable member and the indicator member from their second positions to their first positions and to move the second contact away from the first contact.

11. In combination, rst and second contacts, means for biasing the first contact away from the second contact, a movable member movable to a first position to hold the first contact in engagement with the second contact and movable to a second position to allow the first contact to separate from the second contact, an indicator member having a one Way connection with the movable member and urged from a first position toward a second position for urging the movable member toward the second position, means for normally holding the movable member and the indicator member in their first positions but operative to allow the movable member and the indicator member to move to their second positions upon the occurrence of a predetermined condition, the arrangement being such that even though the indicator member is held in the iirst position, the movable member can move to the second position to allow the iirst contact to separate from the second contact, manually operated means movable from a rst position to a second position to move the movable member and the indicator member from their second positions to their rst positions and to move the second contact away from the rst contact, and detent means for holding the manually operated means in either of its positions.

12. In an overload cut-out switch having switching means and tripping means for opening the switching means upon the occurrence of an overload condition including a latch member and a thermostatic element normally engaging the same but disengaging the latch member upon the occurrence of an overload condition, the combination of, an adjustable support for the thermostatic element, an eccentric carried by the support, a relatively stationary abutment, and resilient means carrying said support and urging the eccentric into engagement with the abutment, the arrangement being such that upon adjustment of said eccentric the support is adjusted to adjust the position of the thermostatic member with respect to the latch member,

' ALBERT L. JUDSON.

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