US1499736A - Safety switch - Google Patents

Description

July 1 1924.

L. P. HYNES ET AL SAFETY SWITCH Filed March 19. 1920 2 Sheets-Sheet. l

July 1, 1924. 1,499,736

L. P. HYNES ET AL SAFETY SWITCH Filed March 19. 1920 2 Sheets-Sheet. 2

Patented July 1, 1924.

UNITED STATES 1,499,736 PATENT, OFFICE.

LEE 1?. HYNES AND PERCY M. GRIFFIN, OF ALBANY, NEW YORK, ASSIGNORS TO CON- SOLIDATED OAR-HEATING COMPANY, OF ALBANY, NEW YORK, A. CORPORATION OF WEST VIRGINIA.

SAFETY SWITCH.

Application filed March 19, 1920. Serial No. 367,256.

To all whom it may concern:

Be it known that we, LEE P. HYNEs, acitizen of the United States, residing at Albany, in the county of Albany and State of New York, and PERCY M. GRIFFIN, a citizen of the United States, residing at Albany, county of Albany and State of New York, have invented certain new and useful Improvements in Safety Switches, the following being a full, clear, and exact disclosure of the one form of our invention which we at present deem preferable.

'F or a detailed description of the present form of our invention, reference may be had to the following specification and to the accompanying drawings forming a part thereof, wherein- Fig. l is a vertical longitudinal section of our device, and

Fig. 2 is a plan thereof with the cover reversed.

Our invention relates to electric switches having the following provisions for safety. The cover of the enclosing box can not be opened when the switch is in its on position, the contacts being then closed and the current flowing. The operating handle extends through a slot in the box and that slot is automatically covered by a plate which the handle draws down overthe slot when moved to on position. The cover of the box is in two sections, one of which ishinged andcontains the slot traversed by the handle.

The opening of this hinged section, after the handle has been moved to off position exposes the replaceable fuse, but does not expose the live terminal, through which the current reaches the switch.

Referring to the drawings, A and. B, which are shown in dotted lines in Fig. 2 represent the two contacts of the switch, the separation or engagement of which causes the opening or the closing of the circuit to be controlled, such, for instance, as the circuit leading to an electric heater. B is the stationary contact and is the one to be moved away from or brought into contact with B. The two contacts are contained within an arc-chute C formed of insulating material and in the shape of an open-ended box or tube. The chute C is located between the' two pole'pieces D and D of a blow-out magnet E which has the well known function of extinguishing any are which may occur between contacts A and B when they are separated at a time when current is flowing between them.

The switch itself is of a well known snap type formed by two overlapped U levers F and G. The lever F is pivoted near its left hand end by pivot-pins f, f to the vertical plates or standards K, K and at its opposite or yoke end is secured one end of a curved spring A which at its opposite end carries the aforesaid contact A. The lever G is larger than F and encloses it, being pivoted near its right end by pivotpins g, g to the aforesaid standards K, K. A spring H is connected to the yoke end of lever G and to a rod 7 near theyoke end of lever F. When the parts of this switch are in the normal closed condition, the lever G is depressed at its outer (left) end as shown in Fig. 1, and the lever Fis nearly horizontal upward at its right end to suddenly separate contacts A and B. This type of switch is well known and not of our invention. The described parts are mounted on an insulating base plate M on the floor of the metalbox, P, P, P. The live terminal of the circuit is connected to contact B "by means of the connector X at the rear of the arc-chute C, this connector X being the only exposed live point in the apparatus, when the box is open. From the contact A the current passes by wire 1 and connector 2 to the coil of the blow-out magnet E and thence by wire 3 and connector 4 to the pole pieces and core of the magnet. On the flat outturned base of pole piece D is adjustably mounted, by means of slot at, a fuse clip T between which and a similar clip T is the fuse WV. From fuseWV the current is conducted to the electric heater, or other consumption device.

The top of the box .is-divided transversely at the hinge Q into two parts, the part Q? at the right of the hinge being permanently secured to'the box and the part Q} at the left thereof being free to be lifted and swung upwards and backwards under certain'conditions. In. the part Q .is a longitudinal slot through which "passes the insulating handle R of the switch. The handle B is securedto the aforesaid lever Gof the switch and has an enlargement R at its upper end.

It also 'passesthrough "a' short opening g in a slide Q which moves to and fro with the handle just inside the box top and forins a cover for the slot in which the handle'R travels. Therefore when the switch is closed. and the handle R is in the upright POSltlOIl' sshocwnjby'; full-.lines in-Fig; .1, the slot' is through althe; slot.

closed-"to prevent, any. access to the switch by a wire or other :piecerwhich,"-but for the slot-cover.Q might be thrust into the box When the handle R is v moved into the position shownin thedotted .lines of Fig. l'rtoopenithe switch, the slot- .pcover Q does not. prevent such movement 10f the handle but islidesback together with it, being upheld and :directed; by the iguidegplate Q on :the' fixed. partxof the cover.

It willbe evident} that when. the switch. is

,- ,closed, the metal-parts thereof, being in vcirzcuit and .-alive, those metal parts ,are Wholly inaccessible from -;ontside the box,

since theehingedxcover. Q can; not 'be raised becanse zthei enlargement R yon the handle W.lll not passithrough the slotin-said cover. The .cover may: also-be padloclred. by. means of, :the lips, J J but even when unlocked it can not bQliifiEQdejllIllBSS the switch isfirst opened by. zmovingihandle-R to its dot-ted- ;-persons.=;handeven if: the cover. Q a is u M'oreover, when the switch is open. a lug 5 iOIlillhQ aforesaid lever iG comesannder, a :lip S aonth'eaforesaidleverTF- Hence the-lever, .F,

-dead-centerline will the switch close.

-- line position. When .the switch :is thus open,

the, only "liveijpart is :the contact B and its connectorpX which ijcan IlOtzbewrettO-llfid by a (which: "it will "be remembered carries 'the 1 .contactg'A .:;can not: berpnessedydown 1 to :olose the, "contactsIA-an'd: 1B whilethe cover is :open. The lugYS isthen-in line .with the pivotal-point" g: of lever and ':pressure thereon by :lip S 'will merely "press against the-*pivotalpoint g and not exert any turn- "'lIIg HOVBDIGDt on; lever .G not allow lever F to descend. Only "when thewhandle R is turned to the leftsubsequent to the closing of the cover Q removing lug S fromsnnder .lip's and bringing the spring H below the At t the same timeithe fuse: *VV will be easily accessiblewhen. the cover Q} islifted, and, by

virtue :of the: adjustable clip T, the apparatusmayibe set :to receive a :fuse of'anyi'desired length. Butithe fuse can bevtaken' out and replaced only when the switchisi'open and in a perfectly safe condition.

lt will be observed that we secure a" snap action :in closing aswell as inseparating the *zcontacts A and-B, since' the spring-actuated lever F is capable ofrm'ovement independ- :ently of @the: handleYR and the f lever G. :F or

this reason, unless some preventative means is providedit would be possiblefor a person 7 inspecting the open box, or replacing a fuse, .to accidentally press down the lever F and 'thereby, bring contact A against contact "B recelvmg, In consequence, ajshocktfrom the live contact B through the movable'contact A to which lever F is connected. This explainsthe importanceof havin lever .1?

locked individually by the lug-g and the lip S when the switch is open.

The arc-chute C .is readily removable. by unscrewing the; side. plates Y, ;Y, .the bottom of the :chutebeing formed by the ,slate- .cure byfLetters Patent-is: V

1. The combination with an'electric' switch of an enclosing box thereforprovidedwith ahinged cover, aswitch handle engagingsaidcoverandhaiving a portion so positioned :as :to prevent opening of the cover when the circuit' th'rough the' switch is .closed',-.and

"means supported independently of the cover for preventing movementof the switchparts when the cover sis-open except-by movement of :the handle. 7 3 c 2. The combination with an electricswitch having a: handle. and members; :capable of movement independently-of the-handle, an

zenclosing box for the switch provided with a movable cover, said switch handle and said .-cover.: having complementalmeans for; preventing opening of :the. cover when circuit through the switch is closed, and means-acmated by movement-ofithe, handleto engage one of said/ switchmembers when the handle is movedlto openpositi-on.

1.3. ".Thecombination with an electric switch havingsa :handle and-.members: capable of movement. independently :of the handle, an enclosing -bOXL for the switch :provided with movable cover, said switch handle and said cover." havingicomplemental; imeans for *pre:

- venting opening-of. thev cover when circuit through the switch .is; closed, and a locking lug :carried :by. the handlecand positioned to engage one rofasaid: switch -members when said handle is moved-to openqposition.

- 4. The combination with an: electrical 5. Thercombinationwithan electric switch- 7: having two relatively: movable actuating .imemherszoflanrenclosingbox for said switch ;;hav1ng a..;movablei rover, meansconnected with one of said members for preventing opening of the cover while the circuit is closed through the switch, and means for preventing movement of the switch independently of a closing movement of the cover after the latter has been moved to open position.

6. The combination with an electric switch having two relatively movable actuating members, of an enclosing box for said switch having a movable cover, means connected with one of said members for preventing opening of the cover while the circuit is closed through the switch, and complemental abutment members on said actuating 15 State of New York, this 17th day of March, 20

LEE P. HYNES. PERCY M. GRIFFIN.

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