US2094293A - Thermal switch - Google Patents

Description

Sept. 28, 1937. R. DUPONT THERMAL SWITCH Filed July 8, 1936 2 Sheets-Sheet 1 R DUPONT THERMAL SWITCH Sept. 28, 1937.

2 Shets-Sheet 2 Filed July 8, 1936 various means being provided in order to release Patented Sept. 28, 1931 PATENT OFFICE THERMAL SWITCH Dupont, Epernay, France Application July 8. 1936. Serial No. 89,594 In France July-l3, 1935 5Cla-ims.

In a patent application filed July 13, 1935, Serial No. 31,295, was described a Press for electrically vulcanizing india-rubber pieces".

The present invention is an electric interrupter destined to cooperate with the thermic hook ar ranged on the heating box.

The-fusible metal is designed upon reaching .the melting point to free the spring blade and break the electric current into the heating box,

the spring blade by the use of the fusible material, in cooperation with a seesaw device.

In the drawings: Fig. 1 shows a seesaw device held in normal position by the fuse weight and closing the current circuit in the heating box.

Fig. 2 shows the same device positioned for breaking the current circuit upon melting of the fuse and rocking of the seesaw bar.

Fig. 3 is a view of the seesaw device with the fuse enclosed into a spheric jacket.

Fig. 4 shows a similarlypivoted swinging bar with end hollows to receive the fuse.

Fig. 5. is a. modification of Fig. -1.

The spring blade together with its hooking method described in the application No. 31,295 are substituted by a seesaw member 2| ensuring on the one hand the closure of the circuit for the heating resistances enclosed into the heating box It, under the action of the weight of a fusible mass 30, and on the other hand breaking the same circuit upon the reverse action of the same fusible mass, owing to its sliding, after being melted to the opposite end of the seesaw member. According to the first embodiment, shown in Figs. 1 and 2, the fusible mass 30 has such a form as notwithstanding the existing slope between A and B (when contact between the electric contacts I! and 20 is established) it cannot, in the solid state, be removed from the point A.

In case the fusible mass would be spheric, it is convenient to make a flat surface portion on which it may rest without rolling; if desired it is possible to make a small depression at the end A of the bar 2| where the fuse is to be arranged.

According to this embodiment the fuse ll, having reached its melting temperature by conductibility of the heat brought through the blade 3| directly subjected to the action of the inner resistances and also by the bar It in contact with this blade ll, flows along to B and swings the member It thus breaking the heating circuit at the points 20 and 2., Fig. 2. When the mass 30 is cold again in B, it is removed and put back at the point A for a following operation.

According to the embodiment of Fig. 3, the fusible mass 30 is enclosed in a light metal sphere, up to its half capacity or so and the sphere. is then closed, the mass acting like a heavy weight in the solid state, the sphere will remain at. the

point A without revolving uponitself. Under the influence of the heat, the mass 30 is brought to'the liquid state, and the sphere'can run along from A to B, as in the previous case. When cold, the fusible mass is removed and arranged for another operation.- In a third form of the device, Fig. 4, the arrangement is as follows: Each end A and B of the seesaw member 2! is made as a small box 2| with a half aperture opposite one to the other. The seesaw at the right time is rocked about its horizontal axis l9 and can also revolve about a vertical axis l9" to bring the fusible mass in the box 2| around to reset the device.

While this fusible mass is melting it flows along to B and is received into the opposite box. The fusible mass remains imprisoned in its housing and cannot escape out of same in any way unless in the liquid state. For this reason, the seesaw bar can assume a horizontal rotary motion and the positions be reversed, the point A becoming B and reciprocally in view of successive operations without any other manipulation.

In the fourth embodiment of the invention according to Fig. 5, a simple ball or cylinder of nonfusible metal of a sufficient weight is laid on the seesaw. This ball of inert metal is however keyed by a fusible metal piece 30 which, melting, releases the metal ball which then will run from A to B, thus causing the bar to go down and break the current between 20 and 20'.

For each of the described devices and in order that the two contacts 20 and 2| (between which is effected the rupture) are always in perfect contact, when the. circuit is closed, the lower contact 10 is mounted on a tension spring 20" sufficiently weak to be overcome by the weight of the fusible mass. v

The small spring holding the contact 20 against the contact 20', when the seesaw is rocked, must be limited in its movement in order that it cannot retain, when the seesaw is in breaking position,

the contact 2. in contact with the contact 20'.

From this reason, the contact 2| has in its lower part a shoulder 20" which limits the movement of same when moved upwards.

Furthermore the. member 2| must be shaped, in each case, like agutter so that the melted material cannot escape laterally while running from the point A to B.

Having now described the object of this invention and in which manner same is to be performed, what I claim is:

1. An electric switch comprising a support, a rocker member pivoted on said support on a horizontal axis, and having a longitudinal channel, a heat conducting blade on which one end of said rocker member may rest, a fusible body held on said one end of said rocker member to hold the same in an inclined position, and electrical contacts held closed by said rockable member' when it is in contact with said blade, said fusible member, when fused by the heat conducted by said blade, being arranged to flow down the channel to the other end of said rocker member to overbalance it and thereby to open the circuit.

2. An electric switch comprising a support, a rocker member pivoted on said support on a horizontal axis, and having a longitudinal channel, a heat conducting blade on which one end of said rocker member may rest, a fusible body held on said one end of said rocker member to hold the same in an inclined position, and electrical contacts held closed by said rockable member when it is in contact with said blade, said fusible member, when fused by the heat conducted by said blade, being arranged to flow down the channel to the other end of said rocker member to overbalance it and thereby to open the circuit, said support being swivelly mounted to turn on a vertical axis.

3. An electric switch comprising a support, a rocker member pivoted on said support on a horizontal axis, and having a longitudinal channel, a heat conducting blade on which one end of said rocker member may rest, a fusible body held on said one end of said rocker member to hold the same in an inclined position, and electrical contacts held closed by said rockable member when it is in contact with said blade, said fusible member, when fused by the heat conducted by said blade, being arranged to flow down the channel to the other end of said rocker member to overbalance it and thereby to open the circuit,

said rockable member having pockets at its ends which communicate only with said channel and are adapted to contain the fusible member in its solid state.

4. In an electric switch, a supporting body, a rocker member pivoted on said body on a horizontal axis, circuit contacts adapted to be controlled by said rocker member, said rocker member having a longitudinally disposed channel extending both ways from the pivotal axis, a heat conducting blade carried by said supporting body, and having a rest portion for holding said rocker member in an inclined position with the higher end thereof in engagement with said rest portion, and a body including a fusible part for holding said higher end in contact with said blade and thus to maintain the circuit contacts closed, said when the fusible part melts to run down said channel to the lower end of said rocker member to turn it on its pivot to separate the circuit contacts.

5. In an electric switch, a supporting body, a rocker member pivotedon said body on a horizontal axis, circuit contacts adapted to be controlled by said rocker member, said rocker member having a longitudinally disposed channel extending both Ways from'the pivotal axis, a heat conducting blade carried by said supporting body, and having a rest portion for holding said rocker member in an inclined position with the higher end thereof in engagement with said rest portion, and a body including a fusible part for holding said higher end in contact with said blade and thus to maintain the circuit contacts closed, said body being located in said channel and adapted when the fusible part melts to run down said channel to the lower end of said rocker member to turn it on its pivot to separate the circuit contacts, said supporting body including a swivel post to which said rocker member is pivoted, said post swiveling on a vertical axis.

ROLAND DUPONT.

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