US 3576962 A
Description (OCR text may contain errors)
United States Patent Jean-Pierre Edmond Nicolas Nice, France Dec. 5, 1968 May 4, 1971 Legrand, Limoges France Dec. 13, 1967 France lnventor Appl. No. Filed Patented Assignee Priority PUSH CONTACT DEVICE 9 Claims, 3 Drawing Figs.
200/167, 200/172 lnt. Cl H01h 9/18, HOlh 3/12  Field of Search 200/83, 83.5, 83.8, 167 (A), 168 (G), 172 (A)  References Cited v UNITED STATES PATENTS 3,146,329 8/1964 Cooper ZOO/168(0) 3,302,269 2/1967 Cooper et a]. 200/83(X) Examiner-11 0. Jones Attorney-Spencer & Kaye ABSTRACT: A push contact device having a small control travel intended for controlling electrical apparatus by current impulses. An operating pushrod projects freely from the center of a concave baseplate by a deformable operating plate against which the said pushrod is supported.
PA'TENTED MAY 41971 INVENTOR: Jean-Pierre Ed Mm fill/Zn; 219C209,
PUSH CONTACT DEVICE The present invention relates to a push contact device, and is more particularly directed to a push Contact with a small travel, intended for the manual control of electrical devices by current impulses.
Push contact devices of this kind are known, and are particularly employed for the control of apparatus such as remote control switches, electric bells, electric latches, relays. etc., but which generally necessitate an operating force which is not negligible (at least 200 grams) applied against a key with a small surface area, of 1 cm. for example, the movement of which is of the order of several millimeters, which necessitates a direct and very localized action by the user, it being necessary in certain cases to locate the switch by groping in a dark or poorly lit room.
The invention has mainly for its object a push Contact device as above defined, which has the advantage that it can be operated by a very small force, this force being applied against a surface of relatively large size.
The invention has also for its object to render the said operating surface luminous by one or more electric bulbs which indicate the state of the controlled device.
The invention will be more clearly understood from an examination of the description which follows below of a preferred but nonlimitative form of construction, reference being made to the accompanying drawings, in which:
FIG. 1 is a cross section of the push contact switch according to the invention, taken along the line H of FIG. 2;
FIG. 2 is a cross section of the same push contact taken along the line ll-ll of FIG. 1; and
FIG. 3 is a front view of the same push contact device.
Reference will now be made to the accompanying drawings. In a casing 11 of insulating material, for example moulded plastic material, the shape of which is of little importance, is mounted an electric Contact mechanism of the type known by the name of microswitch.
In accordance with the form of embodiment shown, this microswitch is made up in the following manner.
A'metal blade 12 is embedded at its two extremities in such manner as to be electrically connected on one side to a first terminal 13. In its plane and projecting laterally on each side, it is provided with two blades 12a defining an axis A-A. On the other hand, on the side opposite to the terminal 13, it is cut longitudinally so as to form a flexible tongue 13b, which is in turn cut away along its major axis to form a slot 13c. Close to its origin, the flexible tongue 13b is supported against a front extremity of a cylindrical pushrod 14.
A stirrup 15, generally of V-shape, can pivot about hollow portions or hooks 15a of its extremities bent back in the form of an S, these hooks cooperating with the blades 12a. This stirrup 15 is provided at its top with a moving contact stud 15b adapted to come into contact with a second terminal 16. At the bottom of the V, a small flanged edge 150 receives one of the extremities of a tension spring 17, housed in the slot 13c of the tongue 13b, this spring being hooked on the other hand at the free extremity of the said tongue'at a point M.
The method of operation of this microswitch considered as a unit is as follows:
In the position of rest, as shown in FIG. 2, the point M is at a level lower than that of the axis A-A and the spring 17 urges the stirrup 15 against the blade 12 through the intermediary of the hooks 15a of the stirrup, which are articulated on the blades 12a; when at rest, the moving contact stud 15b is therefore held apart from the terminal 16.
By depressing the pushrod 14 over a travel I, the point M, this travel I being assumed to be sufficient, is displaced and passes to a level higher than that of the axis A-A, the displacement of the point M being for example 21, taking into account the ratio of the lever arms employed. The spring 17 which is stretched has from that time the effect of causing the stirrup 15 to rock in the direction of a working position symmetrical with the previous rest position with respect to a level plane equal to that of the axis A-A; the moving contact stud 15b then comes into contact with the terminal 16. Taking into account the ratio of the lever arms employed, the displacement of the contact stud 15b is for example three times greater than that of the point M, or finally is equal to 6!. If for example the travel of the pushrod 14 is 0.2, mm., the displacement of the Contact stud 15b is 1.2 mm., which value is generally considered as an acceptable minimum.
The blade 13b, bent by the pushrod 14 in the working position of the mechanism, brings this latter back to the position of rest as soon as the pressure applied to this'pushrod is removed.
In accordance with the invention, the casing 11 is fixed on the rear face of a so-called baseplate 21 of insulating material, which is usually the same as that of the said casing. The plate 21 is for example of a generally square form, the side of which corresponds for example to the width of three or four fingers of the hand. The plate 21 has a slightly concave outer face, for example in the form of a spherical cap, and its depression at the center has a value slightly greater than that of the travel I of the pushrod 14. This pushrod passes freely through the central portion of the plate 21 and projects atrest by the said length I, so that the free extremity of the pushrod is located almost at the level of the edges of the baseplate.
The baseplate 21 is covered on the outer side by a so-called operating .plate 22 which is flat but which can bend under the action of a very small force, of the order or 20 grams for example, applied at its central portion. The plate 22 is fixed by its edges on the plate 21, for example by means of a frame 23 in which the two plates are inserted, but which may equally well be moulded in one single piece with the plate 22.
The pushrod 14 is mounted between the blade 12 and the operating plate 22 in such manner that any action of depression applied to this latter is transferred to the pushrod. Due to the presence of the baseplate 21, the operating plate 22 is protected against excessive forces which may be inadvertently applied thereto.
The baseplate 21 is fixed in an uneven or even an irregular portion of a wall of any kind by means of any known desired fixing means such as clips, lugs, etc.
The operating plate 22 may also be of any kind, either covered with a luminescent coating or translucent.
The baseplate 21 may be suitably pierced with one or a number of holes so as to permit the passage of light emitted by one or more bulbs 25 arranged inside or close to the casing 11, playing the part of pilot lamps" and indicating the condition of the device controlled. In the case of a single bulb, the light which it emits when it is lighted can be transmitted by the pushrod 14'of a transparent or translucent material, for example of Plexiglass. The pilot lamp is then mounted on the axis of the pushrod and the blade 12 is pierced with a hole in the same alignment. In the case of two bulbs 25 (the case shown in the drawings) there is the possibility of using them in different colors, for example green and red, and supplying them through a reversing switch (not shown), the position of which indicates the condition of the electrical device controlled.
1. A push contact device for the control by impulses of an electrical device, of the kind comprising a pushrod and an electric switch controlled by said pushrod, in which said pushrod projects freely from the center of an externally concave baseplate in such manner that the free extremity of said pushrod when at rest, is at the level of the periphery of said baseplate, and in which said baseplate is covered externally by a flat flexible operating plate which can be depressed by a very small force and which is covered by a luminescent covering.
2. A push-operated switch actuator for a microswitch, comprising in combination:
a housing including a baseplate having a concave exterior face and an opening at its center;
a pushrod extending through said opening and movable with respect to said baseplate for actuating the microswitch; and
a normally flat, flexible, planar, translucent operating plate associated with an interior lighting arrangement supported at its periphery against the periphery of said exterior face of said baseplate said pushrod contacting the center of said operating plate and being moved to actuate the microswitch when a force is exerted on said operating plate for moving the central portion thereof toward said exterior face of said baseplate 3. An actuator as claimed in claim 2, in which said interior lighting anangement comprises a pilot lamp which indicates the condition of the microswitch being controlled.
4. An actuator as claimed in claim 2, in which said interior lighting arrangement comprises two pilot lamps indicating the condition of the microswitch being controlled.
5. An actuator as claimed in claim 2, in which said interior lighting arrangement is placed adjacent the interior face of said baseplate and in which said baseplate is provided with holes permitting the light from said interior lighting arrangement to reach the operating plate.
6. An actuator as claimed in claim 2, in which the pushrod is of light-transmitting material.
7. A push contact device for the control by impulses of an electrical device, comprising a pushrod and an electric switch controlled by said pushrod, in which said pushrod projects freely from the center of an externally concave baseplate in such manner that the free extremity of said pushrod when at rest is at the level of the periphery of said baseplate, and in which said baseplate is covered externally by a flat flexible operating plate which can be depressed by a very small force, which is translucent, and which is associated with an interior lighting arrangement.
8. A push contact device for the control by impulses of an electrical device, comprising:
a pushrod projecting freely from the center of an externally concave plate in such manner that the free extremity of said pushrod when at rest is at the level of the periphery of said baseplate said baseplate being covered externally by a flat flexible operating plate which can be depressed by a very small force; and
an electric switch controlled by said pushrod and comprising: a contact stud movable between a position of rest in which it is spaced apart from a contact-terminal and a working position in which it is applied againstsaid terminal, in response to a depression applied on said pushrod; lever arms which introduce a substantial ratio of multiplication between the depression travel of said pushrod and the travel of said contact stud, said lever arms including a deformable blade fixed at one of its ex tremities and electrically connected to a second contact terminal, said blade being acted upon by the pushrod in its central position and having a slot formed in its free extremity, and a stirrup articulated on two fixed blades in the vicinity of the free extremity of said first-mentioned blade and extending substantially parallel to said blade from said fixed blades and in the direction of the fixed extremity of said first-mentioned blade, said stirrup carrying said contact stud in its curved portion; and a spring coupled' on the one hand to the free extremity of said firstmentioned blade by means of the slot in said blade, and on the other hand to the curved portion of said stirrup.
9. A push-operated switch actuator for a microswitch, comprising in combination:
a housing including a baseplate having a concave exterior face and baseplate opening at its center;
a pushrod extending through said opening and movable with respect to said baseplate for actuating the microswitch; and
a normally flat, flexible planar operating plate covered with a luminescent covering and supported at its periphery against the periphery of said exterior face of said baseplate, said pushrod contacting the center of said operating plate and being moved to actuate the microswitch when a force is exerted on said operating plate for moving the central portion thereof toward said exterior face of said baseplate.