US2757248A - Switch-operating mechanism - Google Patents

Description

July 31, 1956 H. M. STIEGLITZ ,2

WTQHPBRATING MECHANISU Filed Doc. 23, 1953 2 Sheets-Sheet 1 INVENTOR- HENRY M. snsurz,

B 4M 67 ATTORNEYS.

July 31, 1956 H. M. STIEGLITZ SWITCH-OPERATING MECHANISM 2 Sheets-Sheet 2 Filed Dec. 23, 1955 INVENTOR, HENRY M. ST/EGL/TZ,

ATTORNEYS.

United States Patent SWITCH-OPERATING MECHANISM Henry M. Stieglitz, St. Louis, Mo, assignor to Frank Adam Electric Company, St. Louis, Mo 2 corporation of Missouri Application December 23, 1953, Serial No. 399,900

8 Claims. (Cl. 200-50) In my copending application, Serial No. 284,009, filed April 24, 1952, now Patent No. 2,674,666, of which this application is a continuation-in-part, a switch-operating handle is shown mounted upon a fixed front portion of a switch enclosure so as to be movable between positions extending across and clear of a hinged fuse access door. Switch contacts and safety interlock mechanism within the enclosure are controlled by the switch handle, the circuit being closed and the door locked when the handle extends across the door and the circuit being opened and the door unlocked when the handle is swung clear of the door.

Herein, I disclose a structure wherein the switch handle is mounted on the front of the enclosure, but with the entire front of the cabinet constituting a hinged door. The condition of the circuit is shown by an indicator, which is movable beneath a port in the door to expose alternatively On-Olf indicia. The indicator may also form a part of certain safety interlock mechanism for preventing unskilled personnel from attempting replacement of the fuses without opening the switch, but in this instance, if desired, the interlock mechanism may be rendered inoperative. Among the other objects of the invention may be noted the provision of a construction that permits the door to be reclosed without danger of jamming the mechanism, whether the contacts be opened or closed; and the provision of apparatus of the type described that discourages manipulation of the switch when the door is open.

Briefly, in the attainment of these objectives, an indicating member is coupled to the switch mechanism and is mounted beneath a port in the front of the enclosure for movement between switch-1n and switch-Off positions. The switch mechanism is driven from a crossbar extending beneath the door, and the switch handle carries an inner cam having projecting posts which straddle the crossbar when the door is closed, thereby to permit actuation of the switch. Although the indicating member could cooperate directly with a door hook to function as a safety interlock, a preferred arrangement contemplates the addition of a latching element movably mounted on the indicating member and normally biased into locking engagement with the door hook. As such, this latching element may be secured, as by a screw, clear of its doorlocking position to render the interlock inoperative, and otherwise provides for jam-free reclosure of the door. Moreover, the latching element may have a relatively small notch shaped to permit opening of the door when the switch handle is moved from its circuit-closed position, but an amount insufiicient to overcenter the switch mechanism, thereby to afford skilled personnel access to the enclosure without opening the circuit.

Other features of the invention will be in part apparent from and in part pointed out in the following detail description taken in connection with the accompanying drawings, in which:

Fig. 1 is an oblique view of the switch apparatus herein disclosed, portions of the front door being broken away;

Patented July 31, 1956 Fig. 2 is an enlarged oblique view from within the cabinet, showing details of the indicator plate and associated mechanism;

Fig. 3 is a sectional view taken in a plane parallel to the front of the cabinet;

Fig. 4 is a sectional view taken in a plane parallel to the side of the cabinet;

Fig. 5 is a view similar to that of Fig. 3, but showing a changed position of parts wherein the interlock is rendered inoperative; and

Fig. 6 is a vertical section taken on the line 66 of Fig. 5.

Referring now to the drawings, Fig. 1 illustrates an enclosure 1, having, a rear panel 3, side panels 5, and end panels 7. On the rear panel 3, there would be mounted one or more switches (not shown) and associated fuse holders, the details of which do not form a part of this invention but which are shown, for example, in United States Patent No. 2,310,918. The fuse holders face toward the front of the housing, and front panel 9 is hinged at 11 so as to permit replacement of the fuses. A crank 13, which is journaled at its ends 15 in the side panels 5, extends across the rear panel 3 of the enclosure for actuating cooperation with such switches or contacts.

An exterior switch handle or lever 17 is mounted on the front cover 9 for swinging movement in a plane parallel to that of the cover. A lost-motion overcentering mechanism generally designated 19 is located at the sides 5 of the enclosure to couple the switch-operating handle 17 to the crank 13 and impart snap action to the switch contacts. This overcentering mechanism 19 comprises crank-actuating plates 21 pivoted on the ends 15 of the crank 13, one at each side of the enclosure. Each plate 21 has a pair of spaced crank-actuating lugs, one lug 23 being adapted to throw the crank 13 to circuit-closed position (Fig. 1) and the other lug 25 being adapted to throw the crank to circuit-open position (Fig. 2). The overcentering action is supplied by spring operator 31, one end 29 of which engages the plate 21 at 27 and the other end of which is received through a support 33 fixed to the adjacent side 5 of the enclosure.

The crank-operating plates 21 are swung between alternative circuit-open and circuit-closed positions by associated links 35. One end 37 of link 35 is received through an aperture 39 in the associated plate 21, whereas the other end 47 of the link is received through an aperture 43 in an arm of a U-shaped member 45, which is pivoted at 47 on the side panels 5. A crossbar 49 of the member 45 extends across the enclosure beneath the front cover 9 and adjacent the switch handle 17.

The switch handle 17 is fixed upon the outer end of a shaft 51, which itself is rotary within a sleeve 53 that projects from the outer face of the front panel 9. At its inner end, the shaft 51 carries a cam plate 55, which plate has depending posts 57 spaced apart to straddle the crossbar 49, so that it is swung toward and away from the overcentering mechanism 19 upon manipulation of the handle.

As such, the apparatus herein is similar to that described in my copending application Serial No. 284,009, filed April 24, 1952, now Patent No. 2,674,666, for Switch-0perating Mechanism Interlock, the only difference being that the entire front panel is hinged rather than a portion thereof. Whereas with the device described in that application, circuit conditions were indicated by the position of the switch handle, the device disclosed herein provides for indication of circuit conditions by means of an indexed plate 59 movable beneath an opening 61 in a right-angular bracket 67, on the side wall 5 which is directly below a similar hole 62 in the cover panel 9.

This indicator plate 59 is mechanically coupled to one of the switch-operating links 35. Referring to Fig. 2, the plate is shown to be of a right-angular shape with a front portion 63 and a side portion 65. The right-angular bracket 67 is riveted at 69 to the side walls so as to form a support for the front portion 63 of the indicator plate. The side portion 65 includes a spacing lug 71 riding against the side panel of the enclosure and guiding slots 73 which slidably receive guiding rivets 78 projecting from the side panel 5. A pin 77 extends from the switch-actuating link 35 through an opening '79 in the indicator plate to move the plate upon operation of the switch. It will be understood that the front portion 63 is suitably marked with On-Off indicia which are alternatively exposed through the openings 61 and 62in the front cover 9, upon movement of the indicator plate between upper and lowermost positions corresponding, respectively, to switch-open and switch-closed conditions.

The indicator plate also forms part of a safety interlock for locking the front cover or door 9 when the circuit is closed. A latch hook 81 is fixed to the inner surface of the front panel 9 for cooperation with the interlock mechanism. Notches 83 and 85 are formed in the front portion of the indicator plate in position for alignment with the latch hook when the indicator plate is in either circuit-open or circuit-closed positions. The upper notch 85, however, is blocked by a latch plate 87 pivoted at 8% on the indicator plate and spring biased at 91 to a position overlying the notch 85. This latch plate extends at 93 through a slot 95 in the upper portion of the indicator plate, the slot thereby limiting the outward movement of the latch plate 87. Consequently, when the indicator plate is in its circuit-closed position, the latch hook 81 engages the back of the latch plate 87, to prevent opening of the door. Should the door be initially open and the switch moved to the circuit-closed condition, so that the notch 85 would align with the latch hook 89, the door may be closed without danger of jamming, because the wedge-shaped hook engages the latch plate 87 to move it clear of the notch 85 against the bias of a spring 91.

The invention also contemplates, as a feature of operation, that under certain conditions it may be necessary to open the front panel without opening the switch, but that this should be done only by skilled personnel. To that end, there is relatively small notch 97 (formed by the lug 99 which engages the spring 91) permitting the withdrawal of the latch hook provided this relatively small notch 97 is aligned with the latch hook. The condition of alignment, however, occurs only when the switch handle or switch parts are moved toward open-circuit positions an amount insuflicient to throw the overcentering mechanism 19. When the handle is positioned thus, the overcentering springs 31 exert a considerable bias upon the parts including the switch handle, hence it is not apparent to the uninitiated that the door could be opened with the handle so manipulated. A skilled technician competent to work on live equipment may be informed of this feature of operation. It is readily apparent that the door may be reclosed with the switch contacts either open or closed without danger of jamming the mechanism, inasmuch as the latching plate 87 swings inwardly to clear the latch hook.

As a still further feature, the safety interlock may be rendered inoperative by those who dislike interlocks. A screw 101 normally is located in the upper tip 93 of the latch plate, but may be withdrawn and inserted through an opening 103 in the indicator plate and screwed Within a tapped hole 105 in the latch plate to secure the latch plate 87 clear of the notch 85. When this is done, the front cover may be opened under either circuit-open or circuit-closed conditions.

From the foregoing description, it is apparent that those skilled in the art will understand the structure, function and mode of operation of the invention herein disclosed, and appreciate the advantages thereof. Although one embodiment has been disclosed in detail, it is to be understood that the invention is not limited thereto, but the drawings and description thereof are to be understood as being merely illustrative. For example, the latching element 87 might be removed and the notch omitted so that the indicating element 59 would also function as an interlock. It is realized that many modifications and varitions will present themselves to those skilled in the art without departing from the spirit of this invention or the scope thereof as set forth in the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In enclosed switch gear having side panels and a front panel hinged thereto, a spring-biased overcentering switch-actuating device, a switch-actutaing link extending therefrom along at least one side of the enclosure and a LJ-shaped switch-actuating member pivoted to said side walls, said switch-actuating link being coupled to said U-shapcd member and said U-shaped member having a cross arm extending adiacent said hinged front panel; the improvement comprising an indicating member slidably mounted on one of said side walls and coupled to said switch-actuating link for movement therewith, said member having a portion extending in a plane parallel to that of said front panel, and said front panel having an opening for exposing a. portion of said indicating memher.

2. Apparatus as set forth in claim 1, further including a latch hook mounted on said hinged front panel adjacent said indicating element, and interlock means mounted on said indicating element cooperable with said latch hook.

3. Apparatus as set forth in claim 2, wherein said interlock means comprises a latch member pivotally mounted on said indicating element for swinging movement in a plane parallel to that of said front panel.

4. Apparatus as set forth in claim 3, wherein said indi cating element includes notch means for releasing said latch hook when the switch is in circuit-open position and additional notch means exposing said latch plate, said latch plate including notch means for releasing said latch hook upon movement of said overcentering device toward said circuit-open position but an amount insufficient to overcenter said device.

5. In enclosed switch gear having side walls, a hinged front door, a movable switch-actuating member mounted within the switch enclosure for movement beneath said door, and an exterior operating handle movably mounted on said door; the improvement comprising an operating element carried by the door for movement with said handle, said operating element being cooperable with said switch-actuating member when the door is closed but being releasable from said switch-actuating member upon opening of the door, an indicator element movably mounted upon one of said side walls for movement adjacent and parallel to said door between circuit-on and circuit-off positions, said door having an opening through which said indicating element is exposed, and a linkage interconnecting said indicator element and said switch-actuating memher.

6. Apparatus as set forth in claim 5, further including a latch hook fixed to said door adjacent said indicator element, said indicator element having a part moved into locking cooperation with said latch hook when in its circuit-011 position and moved out of locking engagement with said latch hook when in its circuit-oil position.

7. Apparatus as set forth in claim 5, further including a latch hook fixed to said door adjacent said indicator element, said indicator element being clear of said latch hook in either the circuit-on or circuit-off positions, a latching element movably mounted upon said indicator element for locking cooperation with said latch hook when the indicator element is in its circuit-on position, and means normally biasing said latching element into locking engagement with the latch hook when the door is closed but permitting temporary displacement of the latching element clear of the hook, thereby to permit closure of the door when the indicator element is in its circuit-on position.

8. Apparatus as set forth in claim 7, further including a selector element for relatively permanently securing said movable latching element clear of said latch hook when the indicator element is in its circuit-on position, thereby to render the interlock inoperative.

1,321,244 Platt Nov. 11, 1919 Freeman Apr. 11, Kries Oct. 14, Widmer May 28, Sachs Jan. 1, Rowe June 20, Runke et a1. Sept. 17, Rowe Oct. 1, Landmeier July 16, Stieglitz Apr. 6,

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