RU2574956C2 - Electromechanical time relay - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: electromechanical time relay comprises clockwork, at which output shaft there is a cam (3) designed to impact plate (8) of movable contact (9). Plate (8) comprises a bended section shaped as a ledge and formed by two flat surfaces (81, 83) and cylindrical surface (82) matching them; the above section is made so that it can interact with cam (3).

EFFECT: simplified design and improved wear resistance of the electromechanical time relay.

3 cl, 3 dwg, 1 tbl

Description

The invention relates to switching devices that operate depending on the time, and more particularly to an electromechanical time relay.

It is known an electromechanical time relay containing a clock mechanism, on the output shaft of which a beam is fixed with a movable contact (contact bridge) closing the fixed contacts [1, p. 313]. The disadvantage of this relay is that the contact interaction is carried out in conditions of intense friction when the sliding contact is sliding relative to the fixed contacts. The addition of mechanical and electrical discharge erosion reduces the durability of the contacts.

Known electromechanical time relay containing a clock mechanism, on the output shaft of which is fixed a cam acting on the movable contact plate [2] (prototype). The impact of the cam on the plate is carried out by means of a heel mounted on this plate. The presence of the heel complicates the design of the contact device. The rigidity increases and the elastic deflection of the plate decreases, which increases the likelihood of breakage. In addition, the almost complete absence of slippage in the contact interaction zone leads to insufficient self-cleaning of the contacts. This negatively affects the durability of the contacts and the resource of the relay as a whole.

The present invention aims to simplify the design and increase the life of the relay.

The new electromechanical time relay contains a clock mechanism, on the output shaft of which a cam is fixed, acting on the movable contact plate.

The movable contact plate contains a curved plate portion interacting with the cam in the form of a protrusion formed by two flat and mating cylindrical surfaces.

The acute angle between the plate and the first protrusion plane facing the cam is 40 ... 50 °, and the acute angle between the plate and the second protrusion plane is 25 ... 35 °.

The radius of the cylindrical surface of the ledge of the plate is set depending on the magnitude of the stroke of the plate according to the formula:

R = k

where k = 0.9 ... 1.1;

S is the magnitude of the stroke of the tip of the protrusion of the plate.

Simplification of the design is achieved by eliminating the heel mounted on the plate and serving to interact with the cam.

The increase in wear resistance is ensured by the presence of a small optimum slip rate in the contact interaction zone, which contributes to their self-cleaning.

In FIG. 1 is a front view of the relay; FIG. 2 is an enlarged view of the structure of the contact block (view A from FIG. 1), FIG. 3 is a diagram of the interaction of contacts.

The electromechanical time relay contains a clock mechanism 1, on the output shaft 2 of which a cam 3 is fixed with two cylindrical working (contact) surfaces interacting with the contact plates of two contact blocks 4 and 5 (Fig. 1). The contact block 4 is attached to the watch case 1 using the strap 6 and screw 7. The contact block 5 is fixed in the same way. Each of the blocks has the ability to rotate around the axis of the clock mechanism when the screw is released 7. The presence of two contact blocks allows sequential with a given time interval inclusion of two electric circuits.

The contact block 4 includes a plate 8 with a movable contact 9 and a plate 10 with a fixed contact 11 (Fig. 2). The plate 8 comprises a bent portion interacting with the cam in the form of a protrusion formed by two flat surfaces 81 and 83 and a cylindrical surface 82 mating them.

The table shows as an example the specific values of the design parameters.

S mm k R mm α1, ° α2, ° one one one 45 thirty α1 is the angle between the plate 8 and the plane of the protrusion 81 (Fig. 2); α2 is the angle between the plate 8 and the plane of the protrusion 83.

The presence of unequal values of the angles α1 and α2 reflects various conditions of contact interaction when closing and opening contacts.

The time relay operates as follows.

When the relay is turned on, clockwise rotation of the output shaft 2 of the clock mechanism 1 starts. Cam 3 first closes the contacts of block 5, then the contacts of block 4 (Fig. 1). The cylindrical section of the cam 3 sequentially acts on the sections 81, 82 and 83 of the protrusion of the plate 8. As a result, the plate 8 is bent and the contacts 9 and 11 are closed (Fig. 2).

When the force of the cam 3 on the cylindrical portion 82 of the protrusion of the plate 8, the angle between the flat sections 81 and 83 increases as a result of bending. In this case, the movable contact 9 moves with sliding along the contact surface of the stationary contact 11 by a small amount of δ (Fig. 3). The presence of slip promotes self-cleaning of contact surfaces.

The new technical solution allows to simplify the design, reduce costs and increase the life of the electromechanical time relay.

Literature

1. V.I. Gurevich. Electrical relays. Device, principle of operation and application. Handbook of electrical engineering. Series "Components and Technologies". - M.: SOLON - Press, 2011 .-- 688 p., Ill.

2. RF patent No. 2075128 (RU). Electromechanical time relay. Published on March 10, 1997, IPC Н01Н 43/12, G04D 23/02.

Claims (3)

1. An electromechanical timer, containing a clock mechanism, on the output shaft of which a cam is fixed, acting on the movable contact plate, characterized in that the movable contact plate contains a curved plate portion interacting with the cam in the form of a protrusion formed by two flat and mating cylindrical surfaces. 2. The time relay according to claim 1, characterized in that the acute angle between the plate and the first protrusion plane facing the cam is 40 ... 50 °, and the acute angle between the plate and the second protrusion plane is 25 ... 35 °. 3. The time relay according to claim 1, characterized in that the radius of the cylindrical surface of the protrusion of the plate is set depending on the magnitude of the stroke of the plate according to the formula:
R = k
where k = 0.9 ... 1.1;
S is the magnitude of the stroke of the tip of the protrusion of the plate.

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