US2171964A - Manually and thermostatically operable switch or circuit breaker - Google Patents

Description

Sept. 5, 1939. R. N.- RbwE 2,171,964

MANUALLY AND THERMOSTATICALLLY OPERABLE SWITCH OR CIRCUIT BREAKER Original Filed May 16, 1936 3 Sheets-Sheet l I {4/14 a7 0 O 46 54 W i v 5.9 g (O\1 551 I S'KNI l IIIIIA 'IIIIII INVENTOR I64 YMOIVO N. ROWE A? 'YVORNEY Sept.

1939- R. N. ROWE 2,171,964

MANUALLY AND THERMOSTATICALLY OPERABLE SWITCH OR CIRCUIT BREAKER 3 SheetsShee1; 2

Original Filed May 16, 1936 I INV RAYMOND A ggfi/f Sept. 5, 1939. R ROWE I 2,171,964

MANUALLY AND THERMOSTATICALLY OPERABLE SWITCH OR CIRCUIT BREAKER Original Filed May 16, 1936 3 Sheets-Sheet 3- 2:: [Z INVENTOR RAYMOND IV. POM/5 BY 44 v RNEY Patented Sept. 5, 1939 UNITED STATES PATENT OFFICE Raymond N. Rowe, Plainville, Conn.,

assignor to The Trumbull Electric Manufacturing Company, Plainville, Conn., a corporation of Connecticut Original application May 16, 1936, Serial No.

80,030, now Patent No.

Divided and tember 12, 1936, Serial 4 Claims.

My invention relates to devices which can be manually or automatically operable to break a circuit and manually operable to close the circuit and which, when automatically opened, may be reset by hand, ready to be closed by hand.

One object is to provide a structure of this kind which is sensitive to automatic thermostatic release.

Another object is to provide a switch of this character which will automatically open the circuit even when the handle is held in the closed I circuit position.

Another object is to provide a switch which can not be closed when the thermostatic device is under an overload condition.

In the drawings Fig. 1 is a plan view of a two-pole ganged switch and circuit breaker utilizing my invention, The parts are in on position.

Fig. 2 is a vertical section along line 22 of Fig. 1.

Fig. 3 is a side elevation of some of the switch parts.

Fig. 4 is a sectional view of the switch and circuit breaker parts in on position.

Fig. 5 is a similar view of these parts in tripped position.

Fig. 6 is an end view of the parts in the same position as in Figs. 1, 2 and 3.

Fig. 7 is an exploded perspective view of parts of a single switch unit.

In order to illustrate a completely operative device I have shown a novel form of switch and circuit breaker in which my improved chamber seal is used.

In the device shown, the switch has an insulating base 0 which may be connected to other bases of identical switches by means of screws or rivets H which pass through connecting straps I2 and I3. As shown, two of these switches are ganged together. It is obvious that they may be used singly or in combinations greater than two when desired.

Mounted on the base is a frame piece I 4, U- shaped in cross section, each arm of the U carrying an extended leg I5. Straddling the frame is a switch yoke l6, pivoted as at I! in a recess of the base. The yokes of a plurality of ganged switches are connected together by an insulating connecting bar l8, operated by a handle l9.

The switch throw piece or rocker 20 is pivoted on axis 2| between the arms of the frame and has a cross bar 22 which connects the sides of the piece together. At its lower end, the throw piece carries a rod 23, which extends on either side 2,125,201, dated July this application Sep- No. 100,414

outside of the confines of the switch frame I4. Between each end of this rod 23 and ears 24 on yoke l6 are stretched springs 25. The rod 23 passes through the contact-carrying plunger 26 which has a contact 21 at one end,

The position of the yoke pivot I1 is so arranged with respect to the pivot axis 2| of the throw piece and. the ends of the springs 25 that movement of the yoke produces a snap action of the plunger and contact in each direction.

A trip piece 28 is also pivoted on axis 2| in the switch frame. This trip piece has a catch roller 29 rotatably mounted between its sides. A resetting bar 30 connects the sides of the piece together.

Arms 3|, on the trip piece 28, carry a cross-rod or catch 32 which extends outward far enough to engage one edge of the switch throw piece 20 to prevent clockwise rotation of the throw piece beyond the catch. The free ends of the arms 3| are engaged by a cross-head 33 on a bar 34. This bar is slidably mounted in a pressure plate 35 which in turn is pivotally held at its ends by seats in the ends of legs I 5 of the switch frame, A spring 36 surrounds bar 34 and presses against head 33 and plate 35. These parts are so positioned with respect to the pivot axis of trip piece 28 that the spring 36 always exerts a pressure tending to turn trip piece 28 in a counter-clockwise direction.

A latch or catch piece 31 is pivotally mounted in frame H as at 38 by ears or pivot lugs 39. One end of this catch piece when the circuit is closed normally abuts against roller 29 on trip piece 28, thus preventing spring 36 from pushing the trip piece to releasing position (see Fig, 2).

To insure normal engagement with the roller 29, a small, light spring 40 is secured between the opposite end of the catch piece and a fixed part of the switch base or frame. An adjusting or calibrating screw 4| is threadedly engaged with the outer end of catch piece 31 and is held in its adjusted positions by lock-spring 42.

This catch piece 31 is released upon a short circuit or overload by any suitable electro-responsive device. As shown, the electro-responsive device consists of a bimetallic strip 43, fixedly mounted at one end with respect to the switch base by conducting support 44.

The free end of the bimetallic strip is attached to one end of a flexible current-carrying cable 45, the other end of the cable being secured to one end of the contact plunger 26. This free end of the thermostatic element will flex upwardly when the strip is heated, thus engaging the end of adjusting screw 4i and tripping the catch piece 31 by overcoming the slight pressure of counterbalancing spring 40, To prevent unnecessary current fiow through the switch parts, a strip of mica or other flexible insulating material 46 is secured to-the top surface of the thermostatic strip 43 between the end of screw 4| and strip 43.

Current is supplied to the electro-responsive element through support 64. Terminal 41 makes connection with a strap 48 which in turn is electrically connected to support 44 by means of a screw or the like 39.

When a plurality of switches are ganged together, adjacent catch pieces 31 are connected for simultaneous movement by means of an insulating bar 50, held tothe catch pieces as by screws 55.

The opposite current side of the switch preferably contains the compression chamber. This chamber is composed of a cup-shaped piece 52 which has a stationary contact piece 53 in its bottom. The cup and contact are electrically connected to terminal 54 by means of a strip 55. The edges of cup 52 are crimped around a heavy insulating tube 58, which fits the inside of the cup very closely.

Seated and sealed within the insulating tube 56 is a hard metallic hollow sealing member The walls of this sealing member fit closely around the surface of the movable contact carrier 26 but not tightly enough to bind the parts together. As shown in Fig. 6, the walls of the sealing member. are provided with a serrated surface in the form of a coarse screw thread surrounding the movable contact carrier. This is the preferred form of sealing means by which the compression within the chamber is maintained sufficiently high to aid in arc extinction.

The operation of the switch is as follows, assuming the parts to be in the off position of Fig. 4: the switch handle l9 and yoke it are moved to the left, the springs 25 being put under increasing tension. When the springs have stretched their maximum amount and the upper or outer end which is attached to the lug 23 passes to the left of the rod 23 they start to contract, pulling the rod 23 to the left. This rod swings the switch throw piece 28 clockwise-and throws the contact-carrying plunger rod 26 against stationary contact 53. The'trip piece 28 and catch piece 31 do not move. The parts are then in the on position of Figs. 1, 2 and 3.

Movement of the handle in the opposite direction causes the above mentioned parts to function in a reverse manner, throwing the switch into normal off" position. Stops or lugs 58 on the switch frame limit the extent of movement of the switch yokes.

When the switch is in on position, current flows from terminal to terminal through the following parts: terminal ti, strap 48, screw connection 49, support 4Q, bimetallic strip 53, cable t5, plunger 26, contact 2?, contact 53, compression chamber wall 52, connecting strip 55, and terminal 5Q.

On a short circuit or overload the thermostatic strip Q3 will be heated and flex upwardly. This will trip the switch mechanism to separate the contacts. Action is as follows: when strip 33 flexes upwardly it lifts screw il upward, tilting catch piece3l counterclockwise around its pivots 39. The other end of the catch piece will then become disengaged from catch roller 29 and spring 35 is able to push trip piece 28 in its counter-clockwise direction. As soon as cross rod .or catch 32 engages the edge of the switch throw 'piece 20, both throw piece and trip piece will be pushed counterclockwise together, and rod 23 with plunger 26 will be pulled away from contacting position. Springs 25 will also move to pull yoke pieces l6 part way toward off position.

The yoke and handle are prevented from going to full off position by means of the trip resetting piece 59 which is fixed to the yoke piece 16. The under surface of this resetting piece will engage resetting bar 30 of trip piece 28 and the pressure of spring 36 will prevent springs 25 from pulling the yoke any farther. The parts are now in the tripped position of Fig. 5.

To reset the switch, after the bimetallic strip has cooled down and assumed normal position, it is merely necessary for the operator to force the handle to full off position.

When the handle is so forced, resetting piece 59 bears against resetting bar 30 and pushes trip piece 28 (against the action of spring 36) clockwise into the position of Fig. 4. Counterbalance spring e0 will pull one end of catch piece 37 downwardly and the other end will engage catch roller 29 to hold the trip piece in place. Resetting bar 30 will also engage the upper surface of catch piece 31 to insure proper resetting at the end of the switch handle movement. The parts are now all in the position of Fig. 4 because the switch thrdw piece 20 and plunger 26 were already in "oif position and have been held there by tension of the spring 25.

When the contacts 27 and 53 are'separated under load or short circuit, arcing'will take place within the compression chamber. Because the chamber is sealed, the pressure, built up by the expanding gases heated by the arc, will act to estinguish the are. To seal the moving contact carrier at its place of entry into the chamber I have provided the structure described above.

It is theorized that the expanding gases, because of the serrations in the wall of 5?, are alternately expanded and contracted. It is believed that this alternate expansion and contraction in rapid succession creates an obstruction to the escape of the gases and that this is why the proper compression is maintained in the chamber.

The tendency of ordinary seals to cause sticking between the chamber wall and the moving contact carrier is obviated by my improved structure.

Another advantage is the fact that although the present seal effectively holds the pressure within the chamber during arc explosion, there is sufficient communication with the outer air to enable the pressures inside and outside of the chamber to equalize by slow leakage after arc interruption. This aids in cooling the chamber and shortens the periods during which the walls of the chamber are subjected to internal pressure.

A further advantage of my invention is the simplicity of the compression chamber structure. The parts of this chamber are easily -manufactured and assembled, and produce a rugged, inexpensive device.

The snap actioncontrol mechanism is readily operated by hand and is very sensitive on the thermostatically operable release and is easily reset. When the circuit is closed it will be automatically opened upon an overload such as a short circuit and can not be held closed by hand.

The arrangement is such that the switch can be i readily built up of units so as to take care of one, two or more lines or wires.

This case is a division from my application Serial Number 80,030, filed May 16, 1936 now Patent 2,125,201 issued July 26th, 1938.

I claim:

1. A' circuit breaker having a frame, a reciprocating switch member, a rocker pivoted in the frame and hinged to the switch member, a hinged yoke having a handle, a spring connecting the hinge point connection between the rocker and the switch member and the yoke for opening and closing the switch with a snap action, a trip piece hinged in the frame, a throwing spring coacting with the trip piece to move it, a pick-up device carried by the trip piece for acting on the rocker to open the circuit, a latch hinged in the frame and adapted to hold the trip piece during normal load conditions, and a thermostatic device for moving the latch out of the path of the trip piece in case of an overload, and a cam carried by the yoke and actuated by the handle and slidably coacting with the trip piece to reset it.

2. A circuit breaker having an insulating base, a frame mounted thereon, a switch member, a rocker pivoted in the frame and connected to the switch member, a yoke hinged at its inner end between the base and the frame and having a handle at its outer end, a spring connecting the rocker, the switch member and the yoke for opening and closing the switch with a snap action, a trip piece hinged in the frame, a throwing spring coacting with the trip piece to move it, a pick-up device actuated by the trip piece for acting on the rocker to open the circuit,- a latch hinged in the frame between the switch member and the hinge of the trip piece and adapted to hold the trip piece during normal load conditions, a thermostatic device for moving the latch out of the path of the trip piece in case of an overload, and means carried by the yoke and. coacting with the trip piece to reset it.

3. A circuit breaker having a frame, a movable switch member, a rocker pivoted in the frame and hinged to the switch member, a hinged yoke having a handle, a spring connecting the hinge point connection between the rocker and the switch member and the yoke for opening and closing the switch with a snap action, a trip piece hinged in the frame, a throwing spring coacting with the trip piece to move it, a pick-up device carried by the trip piece for acting on the rocker to open the circuit, a latch hinged in the frame and adapted to hold the trip piece during normal load conditions, and an overload device for moving the latch out of the path of the trip piece in case of an overload, and means carried by the yoke and actuated by the handle and slidably coacting with the trip piece to reset it.

4. A circuit breaker having a base, a frame mounted thereon, a switch member, a rocker member pivoted in the frame and connected to the switch member, a yoke hinged at its inner end between the base and the frame and having a handle at its outer end, a spring connecting the rocker, the switch member and the yoke for opening and closing the switch with a snap action, a trip piece hinged in the frame, a throwing spring coacting with the trip piece to move it, a pick-up device actuated by the trip piece for acting on the rocker to open the circuit, a latch hinged in the frame between the switch member and the hinge of the trip piece and adapted to hold the trip piece during normal load conditions, an overload device actuated by an overload for moving the latch out of the path of the trip piece in case of an overload, and means carried by the yoke and coacting with the trip piece to reset it.

RAYMOND N. ROWE.

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