US1439692A - Overload-circuit breaker - Google Patents

Description

Dec. 26, 1922. 1,439,692; C. B. COATES.

OVERLOAD CIRCUIT BREAKER.

oruGm/u. msn MAY 1. 1920. 2 SHEETS-sain x..

Dec. 26, 1922. 1,439,692,

xc. B. COMES.

OVERLOAD CIRCUI BREAVKVER.

omGML mw MAY 1. 192o. 2 SHEETS-SHEET 2.

solenoid is also provided with an Patented Dec. `26, 1922.

' 1,439,692 PATENT OFFICE.

CHARLES B. COATES, 0F ERIE, PENNSYLVANIA, ASSIGNOR TO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY. l

OVEBLOAD-CIRCUIT BREAKER.

Original application led Hay 7, 1920,` Serial No. 379,460. Divided and this application led March 14,

To azZZ who/m. t may concern:

Be it known that I, CHARLES B. COATES, a citizen of the United States, now residing at Erie, in the county of Erie and State of Pennsylvania, formerlyI residing at New York, in the county of of New York, have invented certain new and useful .Improvements in Overload-Circuit Breakers, of which the following is a specification, this application being divisional of an original application filed on May 7, 1920, Serial No. 379,460. l

M invention relates to what are known as overload circuit breakers adapted for use with tools, for instance with portable electric drills and the like wherein it becomes necessary to break the circuit in the event that the drill bit should stick or otherwise be given an overload. The object ofy my invention is to provide a novel and eiiicient' construction of arc extinguisher or blowout for a circuit breaker of this character.

In the drawings Fig. 1 is a side elevation of my circuit breaker; Fig. 2 an end elevation thereof viewed from the line 2 2 of Fig. 1 and looking in Athe direction of the arrow; Fig. 3 a erspective of a detail of the contact base; ig. 4 a sectional plan of the switch mechanismtaken on the irregular line 4-4 of Fig. 5; and Fig. 5 a" sectlonal elevation on the line 5-5 of Fig. 2.

Referring to the particular embodiment of my invention which is herein shown for the purpose of a clear and definitev description but which may partake of different forms, the mechanism is mounted on and supported by an angle iron framework 1 carrying a base 41 of insulating material. Themech'anism comprises essentially a solenoid and switch mechanism together with a dashpot arrangement for controlling the movements of the solenoid core or plunger. This solenoid is preferably of the stopped iron clad type consistin of the casing or frame 2, series coil 3 an core or plunger 4. This solenoid is secured to the brackets 5 which in turn are secured to the frame work 1. The

6 which extends into the core opening of the coil and is secured to anend disk or plate 7 inesuitable manner as by screwing thereinto. This plug has a centralA bore in fwhich slides by a nice sliding fit a rod 8 which is made of suitabilenon-magnetic materialsuch as brass,

ew York and Statev iron plug 'which llimits the outward .plate 28 and its plunger 4. Upon the outer 1921. Serial No. 452,162.

This rod is unattached at'either end but is adapted to contact at its right hand end the plunger 4 and at its left hand end the dashpot device as hereinafter explained.

The dashpot device is contained within a casing 9 secured in suitable manner to the casing or frame 2 of the solenoid as by screwing thereinto and locked in place by means of set screw 10. Within this case there is located a cylinder 11 which provides a dashpot chamber 12. A portion of the interior of the casing 9 is of larger diameter than the cylinder 11 with the result that an annular chamber 13 is formed therebetween. This annular space or chamber communi- Cates with the dashpot chamber 12 through the rearward ports 14 and a forward port 15 which is located intermediate the length of the cylinder 11. b

Within the cylinder 11 there reciprocates a piston 16 which has a tubular stem 17 adapted to communicate with opposite sides of the piston through the ports and passages `18 and the port 19 passing through a disk 20 in the left hand end of such stem. The ports and passages 18 are governed by means 'of a check valve within the stem, which vits 'outer end against the flat face of the piston 16 and is adapted to force such piston outwardly to the left when lactuated by means of the plunger 4 in the manner hereinafter explained.

Referring to the anism which is actuated by the plunger 4, the same consists of a bolt 26 secured to the projecting end of the plu-nger in suitable manner asv by screwing thereinto and clamping between the end qthereof and a nut 27 a plate 28 whose upper end is notched in order to receive the lower edge of a bracket or guide 29 which is secured to .and projects forwardly of the right end of the casing 2. This bracket is provided with a'fiange 30 movement of the switch controlling mecliscrew threaded end of the bolt 26 there is mounted two similar adjustable nuts 31 clamping between them a dog .32 separated therefrom by suitable insulating materlal 33. 4This dog projects downwardly and 1s thereby enabled to actuate the switch and its operating means nowv to be descrlbed. I

My switch is of novel constructlon particularly as to the contacts which here consist of three rollers on the one side and two seats or saddles .and -interposed spring; Two of these rollers 34, 34 are of the same diameter but the third roller35 which is interposed between them is of somewhat greater diam-V eter. These rollers are all mounted upon a horizontal rod 36 connecting the outer ends of a yoke or substantially rectangular frame' which is composed of two parallel bell cranks having longv arms 37 and short upright arms 38. These bell cranks are ivoted upon ythe rod 39 at the-upper en /of the standard 40 which is secured to the base or support 41. The upper endsof the bell crank arms 38 are connected by the cross rod 42. These rollers and their yoke are held to the normal downward position shown in Fig. 5 by suitable means such as the spring 43.

These rollers 34 and 35 constitute switch contacts that are adapted to cooperate with other switch contacts which consist of the saddles 44 cooperating with the smaller rollers 34 and with a spring 45 made of suitable material such as bronze or nonarcing material. This spring is secured at its outer end to the plate 46 and its inner end projects forwardly between the two saddles 44 in position tol be contacted by the larger roller 35. The construction and arrangement of these parts are such that the larger roller 35 does not' leave its contact or spring 45 until after the smaller rollers 34 have left their seats in the saddles 44 with the result that the current passes through the larger roller and through its spring when such current is finally broken, and is not thenpassing through the smaller rollers, so that the seats in the saddles for the smaller rollers are always bright and unaffected by any arcing action and therefore always in suitable conditions for' 4carrying the current in service. It will be understood that the rollers and the saddles and the spring are connected to the electrical ,supply wires.A

A shunt coil 47 is provided for the magnetic blowout and for holding the circuit breaker device in open switch position. One end of this coil isconnected to the spring 45 and the other end tothe base 40 so that current flows through it only when the switch is in the open position. This coil is mounted at the upper end of two uprights or stand ards or magnetic yokes 48 which are suitably mounted. This coil cooperates with a pair of magnetic poles 49 which in turn are adapted to attract and hold an iron armai'aaaeca ture "50"mounted upon the switch breaker .device or frame, 37. A pair of magnetlc plugs 51 are secured in the brackets 52 which yare a part of the casting containing the saddles 44 and positioned with their arc gap in the lin'e of possible arc between the`roller 35 and itsspring 45 so as to blowout any such arc. ln thisconstruction these plugs 51 constitute the horns of the magnet and are placed ver close to the roller 35 and 'its spring an moreover they have the same electrlcal polarity as these parts when they are in contact, and lthe same as the spring 45 after the circuit is opened. This is made possible by using electrical insulation 53 between the plugs 51 and the The advantage of this construction is to provide -a very short air gap through the arc and obtain an intense ield for blowing .out such arc.v .y

Describing a cycle of operation of my circuit breaker and starting with the parts in their normal position shown in the drawings, when the tool such as an electric drill is started from a state of rest there is a momentary rush of c'urrentffar in excess of the safe normal running current. The sudden and intense inward pull onthe plun er 4 due to the high current passing throng the coil 3 is opposed by the dashpot. Thls current is of extremely short duration and the port 15 is so placed that' it is not uncovered by the'piston 16 during this rush of starting current. After the drill has been started and is running without load the plunger 4 and dashpot 16 assume the positions shown in the drawings. When the drill is materimagnet yokes 48.

ally slowed down or stopped as by -reason of" the sticking of the drill bit the working current will increase in the solenoid with the result that the plunger will be moved to the left in Fig. 5 and consequently the piston 16 will be likewise moved by reason of the interposed rod 8. Inasmuch as the chamber 12 isa closed one this movement of the piston will "cause a compression of the air to the left of such pistonv thereby opposing themovement of said plunger. When the strai ht side or right hand face of the piston16 as moved sufficiently to the left to uncover the port 15 the annular chamber 13 will act as a bypass and the pressure of lthe air on opposite sides of the piston will be equalized whereu on there will be no further resistance o ered to the movement of the plunger,"

cross rod 42 which together with the movf` able members of the switch are rocked to the dotted line position shown in Fig. 5. The armature 50 is now held magnetically by the poles 49 which is the open switch position.

In this ope-ration of the switch the small rollers 34 leave their seats while the larger roller 35 is still in Contact with its spring and before it breaks contact with such spring. Moreover, the dog 32 does not strike the cross rod 42 of the breaker device until the plunger has moved to that pointwhere the dashpot piston has passed thevv port 15, that is to say the cushioned movement of the plunger 4 occurs before the dog comes into contact with the rod 42 and the cushioning action is relieved at the moment when such dog makes such contact with the rod with the result that the rollers are 'moved out of Contact with their contacts rapidly and with a rapid, snappy action. Afterthe current has thus been interrupted orv cutout the spring 23 will return the piston and the plunger.

In the solenoid an iron clad magnet is preferably employed so that when the current flows through the coil there is magnetic attraction between the adjacent ends of the plunger 4 and the plug 6 and also between the ends of the casing 2 and the plate 28.

I claim:

- l. In an overload circuit breaker, the combination of a ma etically operated switch,

and a shunt coil aving magnetic poles for holding the switch in open position, and also having magnetic poles for blowing out the arc at the switch.

2. In an overload circuit breaker, the com- `bination of a magnetically7 operated switch,

erating with said armature and having elec trically insulated poles for blowing out the. arc at the switch.

4. In an overload circuit breaker, the combination of a magnetically operated switch including a swinging frame carrying movable switch contacts, an armature on said trame and a shunt coil having poles cooperating with said armature and having poles for blowing out the arc at the switch, said coil having yokes and insulation between such yokes and poles.

CHARLES B. ooATEs.

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