US2306568A - Quick breaking thermal relay - Google Patents

Description

1942- J. H. RUBENSTEIN ETAL 2,306,558

7 QUICK BREAKING THERMAL RELAY Filed July 25, 1940 Q 7 w 1/1 1 1* IIIIIIIIIII I dsiy INVENTOR5 ATTORNEYS.

Patented Dec. 29, 1942 QUICK BREAKING THERMAL RELAY Jacob H. Rubenstein and Lawrence J. De Martino, Syracuse, N. Y.

Application July 25, 1940, Serial No. 347,508

Claims.

This invention relates to thermally operated relays wherein the contacts are actuated by a thermostatic bar, usually of bi-metallic construction. The thermostatic bar flexes or bends upon the application of heat thereto as by a resistance coil encircling the bar. Th amount'of movement of the bar and the time required for such movement depends upon the construction of the bar and the amount of heat applied thereto. After the application of heat ceases, it usually requires a like or greater length of time for the bar to pass through its retrograde movement. Because of this characteristic of the device, it is not suitable for use in instances where it is desired to separate the contacts immediately, or substantially immediately, upon the cessation of current to the heating coil of the thermostatic bar.

Ii an attempt is made to adjust the contacts in order to effect engagement of the same just prior to the interruption of the current to the heating coil. the contact pressure betweenthe contacts is very slight, often causing a fluttering at the contacts, or otherwise making a poor engagement. .Even with such adjustment of the contacts, the device can not b used in a situation where it is desired to maintain the circuit through the heating coil closed over a substantial period of time, and to effect immediate separation of the contacts .when the heating circuit is interrupted.

This invention has as an object a quick breaking or opening thermal relay embodying a particularly economical and unique structure permitting the current in the heating coil to be left on for an indefinite period of time, but whereby the contacts ar disengaged almost immediately when the circuit to the heating coil of the thermostatic bar is interrupted.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a top plan view of a therinalrelay v embodying our invention.

Figure 2 is a sideelevational view of the structure shown in Figure 1 with parts shown in section, the section being taken on line 22, Figure 1.

Figure 3 is an end elevational view looking to the left Figure 1, with parts shown in section.

figure 4 is an elevatlonal view of the motion transmitting member cooperable with the contact arms.

Figure 5 is a side elevational view of a modified form of our invention with parts shown in section.

Figure 6 is a fragmentary view illustrating the relative position of the thermostatic arm shortly after the engagement of the contacts.

Figure '7 is a view, similar to Figure 6, illustrating the position of the thermostatic arm subsequent to the engagement of the contacts and during the continued application of heat to the arm.

Figure 8 is a view, similar to Figures 6 and 7, illustrating the position of th thermostatic arm subsequent to the disengagement of the contacts.

The inventionconsists generally in a suitable support or base, a' contact arm and a thermostatic bar or arm. One of these arms is journalled at one end to the support and is frictionally retained against movement. Complemental contacts are carried by the free ends of the arms, and the arrangement is such that upon the application of heat to the thermostatic arm, the normally spaced contacts are moved into engagement, and upon the continuedapplicationof heat to the thermostatic armthe movable arm is moved about its pivot. The free ends of the arms are connected by a lost motion member which is operable to permit engagement of the contacts and to limit the maximum spacing between the contacts. Upon" the cessation of heat to the thermostatic arm, the contacts are immediately, or substantially immediately, separated and as the arm cools off retrograde movement of the movable arm is effected until the parts return to their initial position.

The support or frame here shown is provided with a base l0, an upwardly extending flang II, and a laterally extending flange l2. In the form shown in Figures 1, 2 and 3, a shaft I3 is rotatably journalled in the upright II and is formed at one end with an enlarged head portion I4 and is threaded at the opposite end to receive a nut l5 cooperable with a washer IE to compress spring I! inorder to frictionally restrain the shaft l3 against rotation. It will hereafter be apparent that the frictional restraint of the shaft I3 need only be slight. Suflicient friction may be obtained by making the shaft a close fit in the aperture in which it is journalled. However, we prefer the arrangement of the spring I! and adjusting nut and flexible metal and is mounted upon block at insulating material 2|) arranged on the flange G2. The arm l3 extends transversely of the flange and is provided at its free end with a contact 2|. The fixed end of the arm is may be provided with a suitable terminal screw 22 by means of which a load circuit conductor 22 may be electrically connected to the arm.

The arm i8 is formed of relatively thick metal and is mounted at one end on a block of insulating material 23 superimposed upon the block and the fixed end of arm 59. The assembly is rigidly clamped together and secured to the flange l2, as by screws 24, the arms 98, i9 being insulated from each other and from the screws 24 by means of insulating washers 25 as is conventional in electrical apparatus of this type. The rigid arm I8 is provided with a contact 29 and a suitable terminal screw 21 for the attachment of the load conductor 28 to said arm The thermostatic bar or arm is indicated at and may be of conventional bi-metallic construction. The arm 30 is secured to the enlarged head portion M of the shaft i3 as by screw 3|, and the bar is encircled by a suitable heating coil 32 which, when energized, is operable to apply heat to the barto effect a flexing in spaced apart relation.

When the coil 32 is energized, and accordingly heat is applied to the arm 30: the free end of the arm flexes upwardly or toward the arm l8. This movement also effects movement of the arm 89 toward the arm l8 through the instrumentality of the block 35, and the contacts 2|, 29 are moved into engagement, as illustrated in Figure 6.

Upon the continued energization of the coil 32,

the bar 30 continues to flex but inasmuch as the contacts 2|, 29 are now in engagement, the free end of the bar 30 can notmove upwardly any further and accordingly, rotation of the shaft l3 is effected. When the heating coil 32 is deenergized, the bar 30 moves to straight normal position, as illustrated in Figure 2. The first part of this movement however takes place at the free end of the bar due to the fact that the shaft 3 is irictionally restrained against movement. Accordingly, the contacts 2 I, 29 almost immediately move out of engagement and this movement continues until the top portion of the block 35 engages the top surface of the rigid arm 3. Thereafter, retrograde movement of the free end of the bar 30 is arrested, as illustrated in Figure 8. Thereafter the straightening movement of the bar 30 effects retrograde movement of the shaft N.

In Figure 5, one end of the bar 30 15 rigidly secured to the support as by screw 38 which also serves as a means of connecting the load conductor .22 to the bar. The bar is, of course, suitably insulated from the support.

The relatively rigid or inflexible bar I8 is mounted, at one end, to a similar shaft l3 .iournalled in the support. In this modified form, the flexible arm I9 is omitted and the contact 2| between said contacts.

secured directly to the free end oi the bar SJ. and the insulating block 35is formed with appropriate dimensions for this arrangement. in this structure, the bar 30 is operable to 'move the contacts 2|, 29 into engagement upon energize.- tion of the coil 32 and, upon the continued application of heat, the arm i8 is moved about the axisof the shaft l3 to which it is connected. When current is discontinued to the heating coil 32, the first movement of the free end of the bar ill! effects separation of the contacts 2|, 29 and thereafter the arm i8 is moved in retrograde disection by the block 35 as will be readily apparent.

While we have described specific structures to illustrate our invention, it will be apparent that numerous changes can be made in this structure without in anyway omitting the subject matter of our invention. For example, the support may be of any suitable form or construction and the contact arm I9 may be omitted in the structure shown in Figures 1 to 3, and the contact 2| carried directly by the free end of the bar 30, as illustrated in Figure 5.

It will be observed that we have devised a thermally operated relay which is self compensating in a manner whereby upon cessation of heat to the thermostatic element, the contacts are quickly separated regardless of how long the heat has been previously applied to the element. This structure has proven to be particularly emcient and economical in devices requiring a large number of thermal relays, such as for example pin-ball machines.

What we claim is:

1. A quick breaking thermal relay comprising a support, a contact arm, a thermostatic arm, a member rotatably journalled in said support and frictionally restrained against rotation, one of said arms being rigidly mounted at one end on said support and said other arm being mounted at one end on said rotatable member, contacts associated with the free ends of said arms and being normally arranged in spaced relation, said thermostatic arm being operable upon the application of heat thereto to move said contacts intosengagement, means operable to apply heat to said arm, and means cooperable with the free ends of said arms to limit the maximum spacing 2. A quick breaking thermal relay comprising a support, a contact arm, a thermostatic arm, a member rotatably journalled in said support and frictionally restrained against rotation, one of said arms being rigidly mounted teem end on said support and said other arm being mounted at one end on'said rotatable member, contacts associated with the free ends of said arms and being normally arranged in spaced relation, said thermostatic arm being operable upon the application of heat thereto to move toward said contact arm to move said contacts into engagement and upon the continual application of heat to effect rotation of said rotatable member, and said thermostatic arm being operableupon the cessationot heat'thereto to return said contacts to normal position and thereafter effect retrograde movement of said rotatable member, and

to apply heet to said thermoon said support and said other arm being mounted at one end on said rotatable member, complemental contacts carried by the free ends 01 said arms and being normally arranged in spaced relation, a motion transmitting member cooperable with the free ends of said arms to permit movement of one arm toward the other to efi'ect engagement of said contacts and to limit the maximum spacing between said contacts, said thermostatic arm being operable upon the application of heat thereto to move the free end thereof toward said contact arm and to move said contacts into engagement and upon the continued application of heat to effect rotation of said rotatable member, a heating coil arranged in juxtaposition to said thermostatic arm and operable to apply heat thereto, and said thermostatic arm being operable substantially immediately upon the cessation of heat thereto to move said contacts in normal position and to subsequently effect retrograde movement of said rotatable member.

4. A quick breaking thermal relay comprising a support, a rigid contact arm mounted on said support, a member rotatably journalled in said support and frictionally restrained against rotation, a bi-metallic arm secured at one end to said rotatable member, contacts associated with the free ends of said arms and being normally arranged in spaced relation, a heating coil arranged in juxtaposition to said bi-metallic arm and being operable when energized to apply heat to said arm, said bi-metallic arm being operable upon the application of heat thereto to move the free end thereof toward said rigid arm and move said contacts into engagement and to subsequently effect rotation of said rotatable member, and said bi-metallic arm being operable upon deenergization of said coil to substantially immediately eflect disengagement of said contacts and to subsequently effect retrograde movement of said rotatable member, and means cooperable with the free ends of said arms to limit the maximum spacing between said contacts.

5. A quick breaking thermal relay comprising a support, a contact arm journalled at one end to said support and being frictionally restrained against movement, a thermostatic bar rigidly secured at one end to said support, the free ends of said arm and bar being provided with complemental contacts normally arranged in spaced relation, a motion transmitting member cooperable with the free ends of said am and bar to limit the maximum spacing between said contacts and to permit engagement of said contacts, a heating coil encircling said thermostatic bar and being operable when energized to apply heat to said bar, and said bar being operable upon the application of heat thereto to move the contact carried thereby into engagement with said other contact and upon the continual application of heat to effect movement of said contact am about its pivot, and said bar being operable upon the deenergization or said coil to substantially immediately move said contacts out of engagement and to subsequently effect retrograde movement of said contact arm.

6. A quick breaking thermal relay comprising a support, a rigid contact mounted on said support, a member rotatably journalled in said support, a thermostatic bar secured at one'end to said rotatable member and being provided at its opposite end with a contact, means cooperable with said bar and rigid contact to limit the maximum spacing between said contacts, said bar being operable upon the application of heat thereto to move the contact carried thereby into engagement with said rigid contact, and to subsequently efiect rotation of said rotatable member.

7. A quick breaking thermal relay comprising a support, a rigid contact carried bysaid support, a flexible spring contact carried by said support and. normally spaced from said rigid contact, a member rotatably mounted in said support, a thermostatic bar secured at one end to said rotatable member, means cooperable with said bar and said contacts to eiiect movement of the flexible contact into engagement with said rigid contact upon the application of heat to said thermostatic bar, and to limit the maximum spacing between said bar and said rigid contact.

8. A quick-acting thermal relay comprising a support, a contact mounted on the support, a thermal responsive member movably mounted at one end on said support and frictionally restrained against movement relative to the support and being operable upon change in temperature to move into and out of engagement with said contact, and means cooperable with said contact and said thermal responsive member to limit the spacing therebetween to a predetermined maximum.

9. A quick-acting thermal relay comprising a support, a contact, a thermal responsive member movably mounted at one end to said support and being frictionally restrained against movement relative to the support, the free end of said thermal-responsive member being operable upon change in temperature of said member to move into and out of engagement with said contact, and means cooperable with said thermal responsive member to limit the spacing between said contact and said member to a predetermined maximum.

the free end of said thermal responsive member being operable upon change in temperature to move said contacts into and out of engagement, and means cooperable with said thermal responsive member to limit the spacing between said contacts to a predetermined maximum.

JACOB H. RUBENS'I'EIN. LAWRENCE J. DE MARTINO.

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