US2978137A - Dust cover for automatic telephone switch mechanism - Google Patents

Description

April 1961 E. J. BENlSEK 2,978,137

DUST COVER FOR AUTOMATIC TELEPHONE SWITCH MECHANISM Filed Oct. 2, 1957 INVENTOR. EDWARD J. BENISEK ATTY.

Unitid ai aren 'DUST COVER FOR AUTOMATIC TELEPHONE SWITCH MECHANISM Edward J. Benisek, Geneva, 11]., assignor to Automatic Electric Laboratories, Inc., a corporation of Delaware Filed Oct. 2,1957 Ser- No. 687,664

' 4 Claims. (Cl. 220-18 My inventionrelates in general to covers, and more specifically to an improved dust cover for an electrical switching mechanism such as an automatic Patented Apr. 4, 1961 tain mounting holes and screws on the back of plate 1.

This box 6 is secured to the back of back plate 1 by means of a mounting screw or screws (not shown) which pass through holes in box 6 and into threaded holes in plate 1. One such screw is shown in the prior 687,388, previously mentioned.

A horizontal shelf 7 is'mounted in the usual manner to the lower front side of plate 1 and extends forward at right angles thereto. Shelf 7 is slightly wider than plate 1, and also extends forward to form a base on which the cover rests as will be explained.

telephone means for moving theshaft in a vertical and rotary mo- 7 tion to cause the wipers to connect with a set ofcontacts in said bank. There are also certain relays sets knownas repeaters and other relay setsand such s witches' or relay switching mechanisms are usually mounted on a rectangularly shaped vertical plate having a horizontal shelf at its lower end extending forwardly from its lower edge. The vertical plate usually has backwardly turned sides with bayonet slots therein for mounting the whole assembly on a rack or shelf having pins cooperating with said slots.

In the past the covers for enclosing and dust proofing such devices were usually also provided with extending sides having bayonet slots which hooked over the same pins which supported the switch mechanism on the rack. Due to the closeness of the switches when mounted on the rack such a mounting of the covers sometimes caused a binding of the edges of the covers of two adjacently mounted switches.

One attempt to overcome this difliculty is shown in the prior application of Bjorn Smith, Serial No. 687,388 filed October 1, 1957, on which my invention is in the nature of an improvement.

The switch cover as described in said prior application, basically includes a sheet of metal, such as thin steel plate, bent around in a U shape with a circular front and parallelly extending sides, together with a top plate with its outer edges also of U shape and with its edges turned down over the steel plate and welded thereto as shown. The back and bottom sides of the cover are open.

The object of my improved design is therefore to provide improved latching means for securing the cover to the vertical plate and horizontal shelf of the switch mechanism without any binding of the parts.

Referring to the accompanying sheet of drawings I will now describe the detailed construction of the cover.

Fig. 1 is a side view of my improved cover shown in mounted position on the v vertical plate and shelf of a switching mechanism.

Fig. 2 is a view taken from the top of Fig. 1.

Fig. 3 is a partial view taken from the right side of Fig. 1 showing the top latching means.

Fig. 4 is a partial view taken .in an upward direction from the lower corner of Fig. 1 as indicated by the line 4-4 of Fig. 1.

In the drawing I have shown the usual vertical back mounting plate 1 having its two sides turned back to form mountings flanges 2. and 3 each having a pair of bayonet slots such as 4 and 5 by means of which the switch mechanism is hung or mounted on pins 18 of the usual mounting rack or shelf. There is a metal box or cover 6 secured to the u er rear side of plate 1 which covers cer- The cover is formed of two major parts, the front and sides are formed from a single thin sheet of metal 8, of steel or the like which is formed in a U shape with a semicircular front and parallel sides extending backward therefrom. The top plate 9 is also of thin sheet metal with its front section curved to correspond to the front of plate 8 and with its front and side edges turned down around and welded to the upper edge of plate 8 to hold the same in its proper shape; Small embossed portions such as 8a are'punched out from the upper edges of plate 8 to form locating points against which the turned down edges of plate 9 abut, to center the top plate in welding. The plate 8 has a pair of reinforcing ribs 11 and 12 indented therein and a vertical reinforcing rib formed therein at 13. Another reinforcing element is the sheet of metal 14 which is folded over the lower edge and welded thereto.

The rear edge of top plate 9 is extended beyond the turned down edges which are welded to plate 8 and is curved downward across its free end to form a latching lip 16. This lip 16 is curved downward in a semicircle to conform to and fit snugly over the upper ends of mounting flanges 2 and 3. The ends of lip 16 which extend down over flanges 2 and 3 are tapered or thinned down, as indicated in Fig. 1. Two reinforcing ribs 16a and 16b provide the necessary rigidity to lip 16 so that as it hooks over the ends of 2 and 3 the top of the cover will be held tightly in place.

At the lower front edges of the parallel sides of plate 8 are a pair of. downwardly extending prongs or extensions 17 one of which is shown in Figs. 1 and 4. Each prong has a cam surface 17a which extends over and slides down behind the rear projecting end of horizontal plate 7. As previously stated, this plate 7 is slightly wider than the back plate 1.

When the cover is applied to the frame of the switch mechanism, it is pushed inward in a slightly elevated position until the rear edges 19 engage the pins 18 and lip 16 falls over the upper ends of flanges 2 and 3 and until the prongs 17 pass down behind the rear edges of plate 7. The cover is then pushed downward to the position shown in Fig. 1 and held securely in position against the pins 18 by lip 16 at the top and the prongs or extensions 17.

Having fully described the features and aspects of my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

. What I claim is:

1. The combination with a vertical back plate having a pair of vertical mounting flanges extending backward from the sides thereof with rounded upper ends and having a shelf comprising a horizontal base plate at the lower edge thereof having a semicircular front edge and having back edges extending outward beyond the back plate, of a cover comprising front and side walls and a top plate forming a cover with open back and bottom and with sides conforming to the shape of the back plate and shelf, said top plate having an extending lip curved over to fit said rounded 'upper ends of said flanges, and

application, S.N.

the side walls of said cover having extensions at the lower back edges thereof fitting over the outwardly extending back edges of said shelf, said extending lip engaging said rounded upper ends, and said extensions engaging said outwardly extending back edges of said shelf to form the sole means for holding the cover removably in place, when the cover is placed on the back plate, and said cover requiring only a vertical movement thereof to remove it from the back plate.

2. The combination of cover formed from a piece of sheet metal curved into a U shape with semicircular front and parallel sides, a flat top with a curved front with the edges of its front and sides turned down and rigidly secured to the top of said sheet metal piece, a pair of bosses in the upper rear ends of said sides forming points of alignment by butting against the ends of the turned down sides of said flat top to properly position the top on said front and sides of the piece of sheet metal, With a vertical back plate having a' forwardly extending base plate at its bottom edge, with its side edges extending outward beyond the sides of said back plate, said back plate also having a pair of vertical mounting flanges extending backward from the sides thereof and having rounded upper ends, a curved lip formed on the rear of said top of the cover engaging the said rounded upper ends of said mounting flanges, a pair of downwardly ex tending flanges, one on each of the lower rear edges of said cover sides engaging the extending side edges of said base plate, said lip and said flanges effective to secure 4 the cover in place on said back plate, said cover thereby removable from the back and base plates by a single vertical movement.

3. A combination such as claimed in claim 2 in which the curved lip formed on the top of the cover has the turned down edge thereof tapered in thickness so that the portion extending down over the top of the said rounded upper ends of the mounting flanges is thinner than the upper portion thereof, and a pair of stiffening ribs in said top adjacent said lip to reenforce the same.

4. A combination such as claimed in claim 2, in which there is a vertical stiffening rib extending along each rear edgeof the parallel sides of the cover, said ribs extending down into the extending flanges to stilien the same.

References Cited in the file of this patent UNITED STATES PATENTS 111,225 McCallum Ian. 24, 1871 556,612 Bingaman Mar. 17, 1896 1,065,875 Keagy et a1. .4 June 24, 1913 1,156,974 Chapman Oct. 19, 1915' 1,379,228 Swift May' 24, 1921 1,408,370 Lincoln Feb. 28, 1922 1,6 201'047 Van Valkenburg Mar. 8, 1927 2,184,047 King Dec. 19, 1939 2,497,561 Rose Feb. 14, 1950 2,521,134 Staniti Sept. 5, 1950 2,737,754 Goss' Mar. 13, 1956

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