US1588211A - Safety switch - Google Patents

Description

June 8 1926.

. O. H. VAN AMBURG Er AL SAFETY SWITCH Filed June 25 1923 Their' Att Orhey,

Patented .lune 8, 1926.

UNITED STATES PATENT OFFICE.

OTTO E. VAN AMBURG AND LESLIE A. KEMI'TON, OF BBIDGEPORT, CONNECTICUT, ASSIGNORS T0 GENERAL ELECTRIC COMPANY, A CORPORATION` OF NEW YORK.

SAFETY SWITCH.

Application filed June 25, 1923. Serial No. 647,513.

The present invention relates to electric switches and more especially to safetyv switches. When electric power is utilized in industrial establishments for driving individual machines, it is desirable that the operator of the machine be enabled to st art and stop it at will by closing andv opening the electric/circuit. On account of the daner of serious accidents occurring through ignorance, carelessness or curiosity on the part of an operative in coming in contact with an electrically charged part, it is customary in such power installations to provide safety switches for use in starting .and stopping the machines. The characteristic feature of these switches is that all the elec trically charged parts are locked up in a protective encasement with only the insulated operating handle accessible on the outside thereof.

The object of our invention is to provide an improved safety switch which shall be strong, compact, eiicient in service, capable of standing rough usage, and of low manufacturing cost.

One embodiment of the invention is shown in the accompanying drawing in which Fig.

"1 is a front elevation of our safety switch,

with the switch lever in oli position; Fig. 2 is a vertical section of the enclosing box with the circuit interruptino means shown `in side elevation therein; Fig. 3 is a fragmentary view simil-ar to Fig. 1 but with the switch lever in the on position, and Fig. 4 is a fragmentary elevation of the locking lugs.

The switch mechanism 1 is of the oscillating snap type with the operating handle 2 pivoted at 3 and project-ing through a slot in the box cover. The switch is carried by an insulatingobase plate 4 secured to the bottom of the j x and provided with barriersA 5 between the stationary contacts 6 of the respective circuit phases. Mounted on one end of the hase plate 4 are thermal cutouts 7 connected to the load terminals 8 and the adjacent switch contact-s 6.

The enclosing box is drawn up from sheet steel with its rectan lar bottom 9 and side and end Walls 10 an 11 integral. The cover 12 is made flat and has a eripheral ange 13 fitting about the open si e of the box and is hinged at 14 to the upper end thereof The upper half of the box is provided witl. a false front or apron 15 which serves to maintain enclosure of the switch mechanism.

1 when the cover 12 is raised to inspect or renew the cutout. This apron is in the form of a substantially fiat plate :and is held in place by screws 16 engaging lugs on the opposite side walls 10 of the box. A slot 17 is formed ,in the apron 15 of a size to permit the shank of the switch handle 2 to move back and foith freely therein. A combined shield and locking lever Y18 is pivoted at 19 to theinside of the apron. The shield end 20 of the lever is made T-shaped so as to always underlie and shield the slot 17 in whichever position it may be moved by the extends through an aperture 22 at the center end 23 of the lever is made L-shaped with an aperture 24 adjacent the; angle thereof. It extends througha slot 25 in the right hand side of the box adjacent a bracket or'extension 26 secured thereto and having apertures 27 adjacent its ends' with the upper one of which the aperture 24 of the lever 18 registers in its extreme off position.

The cover 12 is provided with a bracket 29 corresponding to the bracket 26 on the side of the. box and provided with registering apertures 30. When the'pparts are in the positions indicated in Fig. 1, a padlock 31 may be entered in the upper apertures of the brackets 26 and 29 and the locking lever 18 and thereby lock the switch in oil' position and the cover from being raised. By inserting the padlock 31 in the lower apertures of the brackets 26 and 29, only the cover will be secured against movement, while the switch is left free to be opened and closed.

' With the parts in the positions indicated in Fig. 3, the padlock 31 cannot be entered in the upper apertures of the brackets 26 and 29 because of the bent end of the locking lever 18 being disposed in the path and in consequence whereof it is impossible to lock the switch in the on or closed circuit position.

The operating handle 2 is made with a greater diameter than its shank 21 and the shoulder 32 at the inner end of the handle is located substantially lin the plane of the box cover, which has a slot 33 corresponding to slot217 in the apron and a relatively large opening 34 at the lower end thereof whereby.;- the handle may be enabled to clear the cover be in the depressed or in the open switch po- A or' the shield end 20. The outer or locking l sition. Should, however, the handle be raised out of its extreme od position, the sides of the slot 33 will abut the shoulder 32 oi the handle and prevent the lid being raised. f

lin order to render the switch more readily adaptable to stacking in storage and shipping the handle 2 is made disconnectable' .from its shank and this is accomplished by means of a set screw 35 located in a countersunk hole in the handle and engaging a j tapped hole in the shank 2l, and to prevent swiveling of the handle thereon, it is provided at its inner end with a tongue 36 and the shank with a corresponding groove 37.

While we have shown and described the best embodiment of the invention hewn to dit us, we do not desire to be restricted thereto, "What we claim as new and desire to securel by Letters Patent of the United States, is

l. A safety switch comprising a pivotal switch mechanism, its contacts and thermal responding tothe slotin said apron and hav# ing am emm'gqd @PQR at one end of 'its assenti slot vto permit passage of the switch operating means therethrough during opening and closin movements of said cover.

2. safety switch comprising a switch -having a pivoted operating handle, cutout therefor, an apron fixed to said enclosure over the said switch and provided with a guide slot for said switch handle, a combined slot shield and locking'lever pivoted upon said apron and adapted to engage said switch handle at one end and to extend through the side wall of said enclosure at the other, a cover for lthe open side of said enclosure hinged thereto, padlock extensions on sai cover and said enclosure opposite the v projecting end of said lever, said lever and said extensions having apertures adapted to re ister only when -the switch is moved into otr position.

ln witness whereof, we have hereunto set our hands this 21st day of d une, 1923.

@'l'l@ H., VAN AMBURG. LlESlJlE A. KETN.

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