US2139074A - Contact set - Google Patents

Description

Dec. 6, 1938. w. H. FRANK ET A1.

CONTACT SET Filed April 17, 1936 vh E N R O T T. A

Patented Dec. 6, 1938 CONTACT SET William n. Frank and Lawrence E. Fisher, Detroit, Mich.

Application April 17, 1936, Serial No. 74,909

4 Claims.

This application relates to contact sets and Amore particularly to contact sets especially useful in switches such as the one disclosed in application Serial No. 37,291, filed August 22, 1935,

5 by Lawrence E. Fisher and William H. Frank,

which application disclosesI a switch having stationary contacts adapted to be bridged by movable contacts supported in insulation housings having lugs associated with an operating bail which may be moved by suitable switch mechanism to reciprocate the housings and the movable contacts therein towards and from the stationary contacts.

In the contact sets of the switch disclosed in the application aforesaid, the movable contacts are in the nature of slugs adapted to be projected into the'space between the stationary contacts, these' being separated by a barrier formed 'asr part of the housing, in which barrier is mounted the'movable contact. In the contact set of the instant application, the movable contact ls not in the form of a slug adapted to be projected into the space between the stationary contacts, but is in the form of a U-shaped piece adapted to embrace the stationary contacts and bridge them, and the barrier normally separating the stationary contacts is not formed as part of the movable housing but instead is formed as a part of the stationary base mounting the stationary contacts. A

For an understanding of the contact set herein disclosed reference should be had to the appended drawing and the annexed specification. In this drawing,

Fig. 1 is an elevation section of the contact set hereof shown in on position;

Fig. 2 is a similar view with the parts shown in "ofi position;

Fig. 3 is a plan section.

` Referring to the drawing it will be seen that the contact set hereof includes a base I0 of insulation upon which are mounted stationary contacts II. For bridging the stationary contacts there is provided a movable contact I2 supported in the insulation housing I4 which is provided with lugs I5 through whose slots passes the bight of an operating bail IS journalled in opposite sides of a switch box containing the contact set and operated by a suitable switch mechanism.

The movable contact I2 is in the nature of a U-Strap carried by and within the housing and is arranged to embrace the stationary contacts and connect them when moved down into the on" position as indicated in Fig. 1.

Formed as part of the base I0 is a barrier Il earlier disclosed contact set.

(ci. zoo- 163) disposed between the stationary contacts and arranged to project beyond the free ends and the edges of the same, as illustrated in the drawing.

The contacts need not be locked in the barrier recesses seating in the contacts but-may be 5 resiliently vformed and loosely seated in these recesses so as to be urged towards the movable Contact' by vsprings I8 (Fig. 2) also seated in the barrier for r'enhancingV contact pressure. Since theopen end of the housing never clears 10 the free ends of the 'stationary contacta-the movement of theco'ritacts II is limt'edby the housing.

'Ifhe'stationary structure, comprising the stationary contacts, and the barrier; fornis'a piston- 15 like'post constantly'closing theopen 'end 'of the cup-like cylinder comprising the housing, and'its contact' I2; consequently, 'reciprocation of the housing away from-`the base, for switch opening, causes the atmosphere withinthe housing to be 20 exhausted to a greater or lesser eirtent, depending-upon the 4seal between the open end o'f the housingland thepost, and inasmuch as the seal I between these parts is made asfalt-tight as practical, there is formed within the housing, or 25 switch opening, a partial vacuum which is effective in minimizing arcs incident'to switch opening, in certain cases preventing completely the formation of ar'cs incident to switch opening.

Since the barrier continues beyond the free ends of the stationary contacts, any arc that might be formed'ibetween'the tips of the stationary and movable contacts on contact separation is localized and prevented from being drawn out by the presence of the free end of 35 the stationary barrier.

While in general the operation and advantages of the contact set here indicated is substantially like that of the contact set disclosed in the application aforementioned, it will be observed 40 that the construction of the contact setA herein indicated is somewhat different from that of the Firstly, the -movable contact disposes itself outside of the stationary contacts, rather than between them, and secondly, the barrier between the stationary contacts is formed as part of the stationary base, rather than as part of the movable contact housing.

In addition, it will be observed that inasmuch 50 as the surfaces of the stationary contacts which are engaged by the movable contacts are outside surfaces, they are visible on every switch' opening and consequently they might be inspected and checked in order to assure users of 55 switches having these contact sets that satisfactory. wiping contact on contact make takes lace. 1? Furthermore, inasmuch as the stationary contal'cts are backed by the barrier between them. they are more rigid than might otherwise be the case and are consequently less susceptible to damage and vixvijuriou's deilection than might be the case 'were the stationary contacts not so backed, as is the case with the stationary contacts of the earlier disclosed contact sets.

Now having described a contact set of the invention, reference should be had to the claims which follow for a determination of the pro 15,l tection sought herein.

wipes the piston side wall, the cylinder closely and completely surrounding the piston, a contact in the cylinder arranged to wipe the contacts of the piston on their outer surfaces and bridge them, the piston contacts terminating short of the cylinder closing end of the piston, andthe cylinder contacts terminating-short of the piston closed end of the cylinder, the side wall of the piston, at its free end, being proportioned to be wiped bythe cylinder contact on relative separation of the contacts. A-

2. A switch including astatlonary piston comprising a postof insulation havingone end anchored and one ,end free, the piston having separate permanently connected laterally spaced contacts on the. side wall thereof, a cylinder disposed .over the free end of the piston and closed at all parts except for an open end thereof, whichend is normally andconstantly closed and sealed by the piston, with the interior of the cylinder and the outside of the piston being so proportioned relatively that the cylinder in terior wall wipes the piston side wall, the cylinder closely and completely surrounding the piston, a contact in the cylinder arranged to wipe the contacts of the piston on their outer surfaces and bridge them, the piston contacts terminating short of the cylinder closing end of the pis ton, and the cylinder contacts terminating short of the piston closed end of the cylinder, the dimensions and proportions of the piston and cylinder being such thatthe piston fills substantially the entire volume of the cylinder when they are telescopedv completely, the side wall of contacts on the side wall thereof, a cylinder disposed over 'the free end of the piston and closed at all parts except for an open end thereof, which end is normally and constantly closed and sealed by the piston, with the interior of the cylinder and the outside of the piston being so proportioned relatively that the cylinder interior wall wipes the piston side wall. the cylinder closely and completely surrounding the plston,. .a contact in the cylinder arranged to wipe the contacts of the piston on their outer surfac and bridge them, the piston contacts terminating short of the cylinder closing end of the piston, and the cylinder contacts terminating short of the pistonclosed end of the cylinder, the side wall of the piston, at its free end, being proportioned to be wiped by the cylinder contact on relative separation of the contacts, the piston contacts having exposed terminals at the ends thereof near the anchored end of the piston to which stationary conductors may be permanently and immovablyl connected.

4. A switch including a stationary` piston comprising a post of insulation having one end anchored and one end free, the piston having separate permanently connected laterally spaced contacts on the side wall thereof, a cylinder disposed over the free end of theplston and closed at all parts except for an open end thereof, which end is normally and constantly closed and sealed by the piston, with the interior of the cylinder and the outside of the piston beingA so proportioned relatively that the cylinder interiorwall wipes the piston side wall, the cylinder closely and completely surrounding the piston, a contact in the cylinder arranged to wipe the contacts of the piston on their outer surfaces and bridge them,` the piston contacts terminating short of the cylinder closing end of the piston, and the cylinder contacts terminating short of the piston closed end of the cylinder, the dimensions and proportions of the piston and cylinder being such that the piston fills substantially the entire volume of the cylinder when they are telescoped completely, the side wall of the piston, at lts free end, being proportioned to be wiped by the cylinder contact on relative separation of the contacts, the piston contacts having exposed ter minals at the ends thereof near the anchored end of the piston to which stationary conductors may be permanently and immovably connected.

WILLIAM H. FRANK. LAWRENCE E. FISHER.

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