US2740024A - Fluid-proofed switch - Google Patents

Description

March 27, 1956 G, ROGERS 2,740,024

FLUID-PROOFED SWITCH Filed Aug. 17, 1953 /A//EA/To/e: GERALD L. ROGERS,

5y www@ United safes' Patent() FLUID-rimonta) SWITCH Gerald L. Rogers, Clayton, Mo. Appiiemion August 17, 1953, serial No. 374,653

2 claims. (ci. 20o-16s) The present invention relates to a fluid-proofed electric switch of the plunger-operated type that is so covered by a iluid-proong material as to have its working parts thoroughly protected from moisture of all kinds.

Heretofore the principal method of keeping switches uid-proofed has been to enclose them in a diaphragm or bellows chamber. Such practice is both bulky and costly. The present invention differs basically from the foregoing practice by having a switch of the aforesaid type cast or molded into a uid-proofed covering from which only the leads emerge, and which includes a bondedon boot for the operating plunger so arranged that continued or repeated pressure upon that plunger does not interfere with the uid seal.

In the drawings:

Figure 1 is a top view of the present switch, with parts of the huid-proof enclosure in section;

Figure 2 is a side elevation of the switch, with parts of the uid-proof enclosure in section and with the mounting for the switch illustrated in section;

Figure 3 is a bottom view of the switch, with parts of the enclosure in section;

Figure 4 is a back elevation of the switch, with parts of the enclosure in section;

Figure 5 is a section transversely through the cover, taken on the line 5-5 of Figure 1; and

Figure 6 is a similar transverse section through the cover, taken on the line 6 6 of Figure 1.

The internal details of the switch are not shown, but it includes a switch housing 10 with a front panel 11 and a back panel 12. The front panel 11 has a continuation that extends over the top of the switch to form a top panel 13 which appears particularly in Figure 5. There are two solderable electrical terminals at each end of the switch, typified by the terminal 15 in Figure 1 and the terminal 16 in Figure 3. Figures 5 and 6 also show a terminal 15a that is located at the same ends of the switch housing as the terminal 15. It will be understood that there is a similar terminal associated with the terminal 16, the switch construction being, for practical purposes, symmetrical.

The upper panel 13 supports a base 19 of an attachment sleeve 20 that is rigidly attached to the panel and which extends upwardly therefrom. The sleeve 20 has external threads 21 to receive mounting nuts, as will be explained. A slidable switch-operating plunger 22 can reciprocate in and out of the sleeve 20 to operate the switch and, in the particularly illustrated switch, is normally urged outwardly by a spring. The outer end of the plunger 22 is beveled as shown at 23.

Four electrical leads 25, 26, 27 and 28 extend from the terminals 15, 15a, 16 and the other terminal, not shown, adjacent the terminal 16, as will be evident from the drawing. The leads are permanently attached to the respective terminals.

Heretofore there has been no successful way to make a switch of this kind, and especially one with this type of threaded sleeve mounting, for uses in which moisture, such 2,740,024 ,P/ateritgtql,Mar, 27, 1956 2 as water, oil, acid fumes or the like, is a serious factor, except by isolating the switch in a fluid-tight chamber enclosed by a movable diaphragm.` According to the present invention, the switch with the leads attached is made an insert in an yappropriately shaped mold, and a uid- 4 proof enclosure or cover 30.is molded around the switch housing and the ends of the leads. The enclosure completely covers and seals against the insulated leads so as to keep water o r moisture of any kind `from getting into the exposed portions of thewires. This will be a tighter seal, because it is molded onto the leads, than would be an elastic seal that is applied to the leads after molding.

It also will be noted that the covering material extends onto the base 19 of the sleeve 20 and is bonded to and seals all around the circular periphery of that base 19. Preferably, the upper surface of the base 19 is left ex; posed so as to aid in obtaining a secure and tight tit of the switch onto its mounting.

It will also be observed that the entire enclosure is in one piece, which minimizes possibilities of leakage.

At the time the foregoing body enclosure 30 is applied, the boot 32 is likewise bonded in place. Its lower end is bonded onto the outer beveled edge of the sleeve 20, and

its outer end is bonded onto the taper 23 of the plunger 22, leaving the end of the plunger 22 exposed so that it can be actuated. This eliminates applying the switchoperating force to the flexible boot 32, as such would gradually wear the same out and cause leakage into the switch.

The material for the enclosure 30 is a plastic, preferably of the chloride resin or vinyl type, and should be tlexible to allow movement of the leads. The boot 32 is a separate piece, preferably made from a exible synthetic rubber, such as neoprene, so that the switch can be actuated. Its particular characteristics of the materials may be determined in accordance with the uses to which the switch is to be put, so that it will best resist wear and corrosion.

With this construction, the mounting sleeve 20 projects without obstruction so that it may be inserted through a hole in a mounting panel, such as the panel 35 illustrated in Fig. 2. Nuts 36 are threaded onto the sleeve 20, one on each side of the panel 35, so as to firmly attach the switch in place. The enclosure does not interfere with either the insertion of the sleeve 20 in the hole, or the application of the nuts 36, or the tight engagement of the upper edge of the base 19 of the sleeve 20 against the panel. The boot 32 does not project beyond the outer dimension of the sleeve. The enclosure 3i) does not project over the base 19 of the sleeve, so that the tightening of the nuts does not apply any stress to the enclosure that might break the fluid-tight seal.

What is claimed is:

1. An electric switch comprising a box-like switch housing having insulated electric leads extending therefrom; an attachment sleeve secured to the housing and projecting from one side wall thereof, the sleeve being of a diameter less than the dimension of the side wall from which it projects, and being externally threaded and adapted to be inserted through an opening in a support and to receive one or more nuts so that the switch may be mounted on the support; a reciprocable plunger normally projecting from the sleeve, the plunger being movable into and out of the sleeve so as to actuate the switch; an integral unitary duid-proof container completely surrounding the switch housing and the leads, the enclosure extending around and sealing against the insulation on each lead, the enclosure being bonded to the projecting attachment sleeve adjacent the base of the external threads thereon, so as to leave said threads free to receive attaching nuts; and a flexible boot bonded at one end to the outer end of the threaded sleeve beyond the threaded portion and at its other end'to the reciprocable plunger,

the'diameter of 'the'bootbeing no greater than that of thev portion y0f thmluxgssr inward Qfyitsi endmostfsurfaee leaving-said;en dmpstisiirfaeemetsohamhesllungcmmay be actuated withqutrapplyingfprsssuresortheuid'pwvfed boot.

2. The switch loftslam 1,Mherein-heabreaded sleeve has a basefportion iofenlarged diametenmprov-iding,a-circularper-ipheral lateral Wall,fandl an edge -surface'thatis 4 in a plane transverse to the axis of the sleeve, the fluidproof enclosure being secured and sealed to the circular peripheral wall of the base portion of the sleeve, with the edge surface free.

References Cited in the tile of this patent UNITED STATES `vPATENTS 2,367,441 Schwinn Ian. 16, 1945 2,440,943 'Gonsett et al May 4, 1948 2,451,176 schq11mn g w. oct. 12, 1948 2,549,323 McMullen et,al. Apr. 17, 1951 2,625,620 "Hasselbaum Jan. 13,1953 2,650,964 Razdow V Sept. 1, 1953

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