US3031548A

US3031548A - Stop light switch

Info

Publication number: US3031548A
Application number: US805928A
Authority: US
Inventors: Robinson Fay
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-04-13
Filing date: 1959-04-13
Publication date: 1962-04-24
Anticipated expiration: 1979-04-24

Description

April 24, 1962 H. M. ROBIN-SON 3,031,548

STOP LIGHT SWITCH Filed April 13, 1959 2 Sheets-Sheet 1 /2 4 lg 5 INVENTOR.

HER BERT M. RQB] N SON ATTORNEYS STOP LIGHT SWITCH Filed April 13, 1959 2 Sheets-Sheet 2 li 15 [mil] JNVENTOR. HERBERT M. ROBIN SON T 11 ATTORNEYS United States Patent 3. :";31548 STOP LEGHT SWITCH Herhert M. Robinson, 3591 W. (inter Drive, Detroit,

Mich; Fay Robinson, administratrix in estate of Herbert M. Robinson, deceased Filed Apr. 13, 1959, Ser. No. 805,923 4 Claims. (Cl. Nil-81) This invention relates generally to the electrical switch 1 art and, more particularly, to a novel and improved stoplight switch especially adapted for use on vehicles such as trucks, tractors, trailers and the like.

It is the primary object of the present invention to pro- Vlde a novel vehicle stop-light switch which is economical of manufacture, rugged and simple in construction and efiicient in operation.

It is another object of the present invention to provide a stop-light switch which includes a novel and compact piston for moving the contacts of the switch into operative engagement, and which piston is made from a selflubricating and a non-water absorbing material which is functional within the conventional autostandard requirements of temperature, whereby it will operate troublefree in temperatures ranging from 40 degrees below zero F. up to 280 F..

It is a further object of this invention to provide a stoplight switch which incorporates a contact construction that includes means for making an electrical contact to complete the circuit to thestop lights simultaneously at four dilferent points, whereby the usual contact point heating and arcing which is inherent in a switch of this type is -eliminated. The novel switching and contact structure in this stoplight switch provides a positive electrical contact and switching action due to the novelstructure thereof which includes a stationary contact having a pair of upwardly extended, concave upwardly facing, laterally spaced apart contact arms on each end thereof which are adapted to be electrically engaged by an equal number of movable, flexible rounded contacts that are snapped into positive engagement therewith by means of a coil spring.

It is still another object of the present invention to provide a stop-light switch which will possess a long operating life and wherein the need for repairs is reduced to a minimum and, for all practical purposes, is eliminated.

It is a further object of the present invention to provide a stop-light switch which may be disassembled for easy and quick maintenance and inspection by merely removing two screws.

Other objects, features and advantages of this invention will be apparent from the following detailed description and appended claims, reference being had to the accompanying drawings forming a part of the specification wherein like reference numerals designate corresponding parts of the several views.

In the drawings:

FIG. 1 is a side elevational view of a stop-light switch made in accordance with the principles of the invention;

FIG. 2 is an enlarged top plan view of the structure illustrated in FIG. 1;

FIG. 3 is an enlarged bottom plan view of the structure illustrated in FIG. 1;

FIG. 4 is an elevational sectional view of the structure illustrated in FIG. 2, taken along the line 4-4 thereof and looking in the direction of the arrows;

FIG. 5 is a fragmentary elevational sectional view similar to FIG. 4 but showing the contacts engaged to complete a circuit therethrough;

FIG. 6 is a horizontal sectional view of the structure illustrated in FIG. 4, taken along the line 6-6 thereof and looking in the direction of the arrows;

FIG. 7 is a horizontal sectional view of the structure ton;

FIG. 13 is an elevational sectional view of the piston illustrated in FIG. 12, taken along the line 13-13 thereof and looking in the direction of the arrows;

FIG. 14 is a top plan view of a spring contact plate employed in the invention;

FIG. 15 is an elevational sectional view of the structure illustrated in FIG. 14, taken along the line 15-15 thereof and looking in the direction of the arrows;

FIG. 16 is a top plan view of a stationary contact bar employed in the invention;

FIG. 17 is a front end elevational view of the structure illustrated in FIG. 16;

FIG. 18 is a right side elevational view of the structure illustrated in FIG. 16;

' FIG. 19 is a front elevational view of the operating rod employed in the invention; and

FIG. 20 is a right side elevational view of the structure illustrated in FIG. 19.

Referring now to the drawings, and in particular to FIGS. 1 through 5, the numeral 10' indicates the body member which is preferably made from a suitable lightweight material as anodized aluminum. The exterior shape of the body member 10 is preferably hexagonal, whereby, a wrench may be applied thereto for threading the switch in place. Extending downwardly from the lower end of the body member ill is the tapered threaded extension or fitting member 11 for mounting the switch in the air line of an air-brake system as normally employed on trucks, busses and the like. A hole 12 is formed through the fitting member 11 and this hole admits air under pressure to the switch and communicates with the cylinder 13 which is formed in the upper end of the body member 10. The upper end of the hole 12 communicates directly with the tapered recess 14 which is formed centrally in the lower wall 15 of the body member ll).

As shown in FIGS. 4, 5, l2 and 13, a piston generally indicated by the numeral 16 is operatively mounted in the cylinder 13. The piston 16 is preferably made from a polyester type plastic material which is impervious to moisture and is provided on the lower end thereof with an annular sealing member 17 which is disposed in the annular peripheral groove 18 for sealing engagement with the cylinder 13. The sealing member 17 is preferably a conventional silicon 0 ring. The piston 16 is provided with a second larger annular peripheral groove 19 around the upper end thereof which communicates with the four evenly disposed slots 2%} which are formed in the upper end face of the piston. The piston 16 is also functional within the conventional auto standard requirements of temperature, that is, it will operate trouble-free in temperatures ranging from 40 degrees below Zero F. up to approximately 280 F. The good operating characteristics of the piston 16 is due in part to the plastic material from which it is made and in part to the construction of the piston including the annular groove 19 and the slots 20 which prevents swelling and consequent jamming of the piston in the cylinder.

As shown in FIGS. 4, l9 and 20, the lower end of the FIG. 12 is a top plan view of the stop-light switch pisv the upper end of the cylinder .13.

' operatingrod 21 is seated in the hole 22 formed in the side thereof which is seated in the upper end of the cylinder 13. The spacer plate 24 also functions toenclose As best seen in PEG. 1 9, the upper end of the operating rod 21 is recessed as at 26, and, extending upwardly into this recess is the spring retainer finger 27. A spring 28 is seated in the recess 26 with the lower end thereof disposed around the retainer finger 27. The upper end of the spring 28 is seated in the hole 29 which is centrally formed in the boss 30 on the switch cap generally desig nated by the numeral 31. As best seen in FlGS. 8'and 9,

the upper end of the operating rod extends intothe hole 29 and the two diametrical recesses 32 which communicats with the hole 29'. It will be seen that the spring 23 i normally functions to bias or urge the operating rod 21 downwardly which in turn forces the piston 16 to the inoperativeposition shown in FIG. 4. The switch cap 31 'is releasably secured to the body member It by means of the two screws 33 which extend downwardly through the holes 34 in the capand the holes 35 in the spacer plate 24 and into a threadable engagement with the body member a As shown in FIGS.'?., 7, l6 and 17, the stop-light switch includes a pair of contact bars generally indicated by the

numerals

36 and 36a. These contact bars aresubstantially Y-shaped and are identical and interchangeable, and the various parts thereof have been marked with corresponding reference numerals followed by the small letter is connectedto a conductor as 37 at the outer'end thereof by means of the screw 38. The

contact bars

36 and 36a are preferably made from silver plated #18 gage sheet brass. The contact bar 36 includes the connector plate enemas.

has the ends thereof connected to the pair of contact members 54 in the slots 57. The inner end of each of the contact members 54 is slotted as at 58 for the reception of the spring 56. The inner ends 59 of each contact member 54 are adapted to be rockably mounted in the grooves 69 formed on each side of the operating bar21 on each side of the hole 55. As shown in FIGS. 4 and 15, the outer ends of each contact member 54 are arcuately formed into a circular construction so that they will make a pair of firm contacts with the

stationary contact members

42 and 43 on the

contact members

39 and 39a.

.The reverse curve

upper ends

46 and 47 on-the stationary contacts permits smooth engagement between the

contact members

54 and 39 without hindrance or binding in any manner. Y

In operation, the air under pressure would be admitted into the cylinder 13 by meansof the passage 12 when the operator Works the usual brake pedal (not shown). The air under pressure will move the piston 16 upwardly which in turn moves the operating'rod 21 upwardly againstthe pressure of the return spring 28. The curved contact being handled by only one contact or point area. The.

novel contact sturucture of this switch materially reduces the usual point heating and arcing which is inherent in a switch of this type. The cap 31 is made from a suitable plastic insulating material, a i I The novelswitching andcontact structure in this stoplight switch provides a positive electrical contact and Iii switching action due to thefact that it employs a stationary A contact havinga pair of upwardly extended, concave up- Wardlyfacing, laterally spaced apart contact arms on each As shown in FIGS. 16 and 17, the contact bar 36 i are reversely curved outwardly as indicated by the

numerals

46 and 47, respectively. The portion 39 of the contact bar is disposed in the entrance slot 43 formed in the wall of the switch cap 31. The other contact bar portion 39a is disposed in a similar slot 48a at a diametrically opposite position. The switch cap 31 is provided with the circular recess 49 in the lower end thereof. which communicates with the recess 29 andwhich is provided with the two oppositely disposed slots 50. As shown in FIG. 7, the contact bar portions 40 and 41 are adapted to lie in the recess 49, and the

contact portions

42 and 43 are adapted to lie in the slots 50. As shown in FIG. 7 the switch cap 31 is provided with the rounded locating projection 51 which extends into the slot 48 and into a mating curved recess 52 formed in the side of the contact 7 bar portion 39. As shown in FIGS. 10 and 11, the spacer plate 24 is'provided with the circularly spaced apart loeating projections 53 on the upper face thereof for locating the contact bar portions 39.

ating rod 21 is provided with a hole 55 through the center portion thereof, adjacent the upper end. Operatively mounted through the hole 55 is the coil spring 56 which end thereof, which are adapted to be electrically engaged by an equal number of movable, flexible rounded contacts of the switch insures a positive contact every time the switch .is operated regardless of any tilting of the'rhovable contacts relative to the stationary contacts. In'the prior stop-light switches there is a point in the contacti making movement of the contact structure wherein arcing will occur and this inherent defect of *the prior switches is not present in the instant switch, because"the switching action thereof is instantaneous without any delay or lagging action, whereby, the contacts are adapted to instantaneously either make or break contact with each other. e i

While it will be apparent that;the preferred embodiments of the invention herein disclosed are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible tomodification, variation and change without departing from the proper scope or fair meaning of the subjoined claims. It will be seen that when the circular, flexible contact members 54 are in the contact making or operative. position, as shown in FIGS, theyare seated secu'rely'in the mating

concave contact arms

44 and 45 to provide a large; continuous and firm contact surface area therebetween.

The contact members 54 are preferably made from berylpressure is released from'the piston 16, thereturn spring Q 28 will move the operating rod 21 downwardly and the circular contacts 54 will be forced outwardly sidewardly by means of their inner ends pivoting in the recesses 60 on the operating rod 21. It will thus be seen that the downward pressure of spring 56 on the contacts 54 will be decreased to the zero point during such release action. However, because of the flexible curved ends of the contacts 54, a firm contact will be maintained until the operating rod 21 is below the neutral point in its movement. Up to the time that the neutral point is reached, and the contacts are disengaged, the curved contacts 54 will flex and maintain cflicient contact with the

stationary contact arms

44 and 45 and will ride all of these arms with a smooth snapping action, when the operating rod moves beyond the neutral position, because of the reverse curved ends 46 and 47 of the

arms

44 and 45, respectively. The

springs

28 and 56 are preferably made from stainless steel spring wire. It will be understood, that the silicon O ring 17 possesses good inherent self-lubricating characteristics. It will be seen that the contact bars 36 and 36a are fixedly secured to the spacer plate 24 by means of the rivets 61.

What I claim is:

1. A stop light switch, comprising: a body member 1 provided with a fitting for mounting the switch in a vehicle fluid pressure brake system; a piston mounted in said body member and being movable by fluid under pressure; a spacer plate mounted on said body member; a pair of oppositely disposed spaced apart stationary contact members mounted on said spacer plate; a cap mounted on said spacer plate; a piston rod connected to said piston and extended upwardly through said spacer plate and into said cap; means in said cap for normally biasing said piston rod downwardly; each of said stationary contact members having a plurality of upwardly facing concave contact areas; a movable contact means carried on said piston rod; said movable contact means having a plurality of flexible rounded contact ends movable into engagement with said concave contact areas on the stationary contact members to electrically connect the same when said piston is moved upwardly by fluid under pressure and disengageable by said biasing means when the fluid pressure on the piston is released.

2. A stop light switch, comprising: a body member provided with a fitting for mounting the switch in a vehicle fluid pressure brake system; a piston mounted in said body member and being movable by fluid under pressure; a spacer plate mounted on said body member; a pair of oppositely disposed spaced apart stationary contact members mounted on said spacer plate; a cap mounted on said spacer plate; a piston rod connected to said piston and extended upwardly through said spacer plate and into said cap; means in said cap for normally biasing said piston rod downwardly; each of said stationary contact members having a plurality of upwardly facing concave contact areas; a movable contact means carried on said piston rod; said movable contact means including a pair of contact plates having their inner ends pivotally mounted on opposite sides of the piston rod; a pair of flexible rounded contact members formed on the outer end of each of said contact plates; and, a spring interconnected between said contact plates and operable to bias said contact plates upwardly into an inoperative position when said biasing means has moved the piston rod downwardly, and to bias the contact plates downwardly when the piston rod is moved upwardly by said piston to move the rounded contact members into engagement with said concave contact areas on the stationary contact members to electrically connect the same.

3. In a stop light switch of the class described, the combination, comprising: a body member having a cylinder formed therein; a piston movably mounted in said cylinder and movable upwardly by fluid under pressure; a contact housing carried on said body member; a piston rod extended upwardly from said piston and into said contact housing; means in said housing for normally biasing said piston rod downwardly; a pair of oppositely disposed spaced apart stationary contact members in said housing; each of said stationary contact members having a pair of end portions which curve upwardly to form a contact pocket and then curve outwardly to provide a reversely curved contact guide means; a movable contact means carried on said piston rod; said movable contact means including a pair of contact plates having their inner ends pivotally mounted on opposite sides of the piston rod; a pair of flexible rounded contact members formed on the outer end of each of said contact plates; and, a spring interconnected between said contact plates and operable to bias said contact plates upwardly into an inoperative position when said biasing means has moved the piston rod downwardly, and to bias the contact plates downwardly when the piston rod is moved upwardly by said piston to move the rounded contact members into engagement with said contact pockets on the stationary contact members to electrically connect the same.

4. In a switch, the combination, comprising: a body member; a contact housing carried on said body member; a pair of oppositely disposed spaced apart stationary contact members in said housing; each of said stationary contact members having a pair of end portions which curve outwardly to form a contact pocket and then curve sidewardly outwardly to provide a reversely curved contact guide means; an operating rod disposed in said contact housing; a movable contact means carried on said rod and including a pair of contact plates having their inner ends pivotally mounted on opposite sides of the operating rod; at least a pair of flexible rounded contact members formed on the outer end of each of said contact plates; actuating means for moving said rod; a spring interconnected between said contact plates and operable to bias said contact plates into a first position spaced from said contact members when the operating rod is moved in one direction, and to bias the contact plates into a second position when the operating rod is moved in the opposite direction to move the rounded contact members to a second position into engagement with said contact pockets on the stationary contact members to electrically connect the same.

References Cited in the file of this patent UNITED STATES PATENTS 1,909,699 Mahan May 16, 1933 1,919,817 Wilcox July 25, 1933 2,172,412 Robinson Sept. 12, 1939 2,188,948 Huebner Feb. 6, 1940 2,629,791 Le Tourneau Feb. 24, 1953 2,752,447 Shatter June 26, 1956 2,791,658 Beeman May 7, 1957