DE1119375B - Cam-operated electrical contact device - Google Patents

Description

GERMAN

PATENT OFFICE

B51981Vmd / 21c

REGISTRATION DATE: 4th F E B RU AR 1959

NOTICE DEK REGISTRATION AND ISSUE OF EDITORIAL: DECEMBER 14, 1961

The invention relates to cam operated contact devices such as those used in contactors be of the type in which a moving contact under the action of the cams performs two movements, one that is used to switch a fixed contact on and off, and one second, by which a sliding movement is caused between the contacts, while the same with each other get into engagement.

It has been proposed to arrange two cam operated levers to allow separate movements to cause a contact piece; however, these movements were not perpendicular to each other, but both served to open the movable contact. It has also been suggested a contact wiping motion using baffles to create a contact around one in the right Angle to the contacting surfaces to rotate standing axis, while the contact is after mutual Engagement of the surfaces in contact. The "fixed" contact had to be resiliently supported in this case to allow such a movement.

The present invention aims to provide improved means for producing the contact wiping motion create, while the stationary contact remains effectively and firmly stored. The grinding is done through Cam actuation by means of a member, which also closes or opens the cam actuated Causes contact. The grinding motion is vigorous as well as straight to produce similar relative displacements as well as ensuring a grinding effect at all points of the contact surfaces, while losing energy is avoided by friction on the sliding surfaces.

So far, the mentioned two movements were made by a cam surface with the help of one and the same Actuator, e.g. B. a cam roller derived, which was connected to a spring.

The invention aims to provide an improved construction which is separate and more precise Controlling each of the two movements mentioned above entails and is about it also enables a lower camshaft torque to be used than comparable ones for closing Contactor of conventional design is required, in which the torque the preload to be overcome of the camshaft has a considerable size and much is greater than necessary to overcome a spring force provided for the grinding process. The present Invention is directed to this counter-cam operated electrical contact device

Applicant:

The British

Thomson-Houston Company Limited,
London

Representative: Dipl.-Ing. Dr. M. Herzfeld, patent attorney, Düsseldorf, Kreuzstr. 32

Claimed priority:
Great Britain 7 February 1958

John Ansley Watson, Rugby, Warwickshire

(Great Britain),
has been named as the inventor

force to reduce the maximum torque required by a camshaft which is rotated to actuate a contact.

According to the invention, this is achieved in that the two movements mentioned are carried out separately Actuators derived from one and the same cam surface or from different cam surfaces, which are rotated by means of a common camshaft, can be controlled. in the In the latter case, at least one of the cam surfaces can be designed to be adjustable, so that the spatial Angular relationship of the effective cam surfaces changed and the temporal relationship of the two movements can be adjusted to the lowest torque requirement.

Accordingly, the present invention proceeds from a cam operated electrical contact device which has a stationary and a movable contact piece, the movable contact piece is carried by a rocker arm biased by a spring.

Such a device is characterized according to the invention in that first and second Cam and cam follower devices are lever connected to the rocker arm to allow two movements essentially in the same plane, however

109 749/426

at right angles to each other, and that one movement causes the movable one Contact piece grinds on the stationary contact piece.

For a better understanding, the invention will be explained in detail with reference to the drawings in which preferred embodiments of the invention are illustrated, for example are.

Fig. 1 is a front view of an embodiment;

Fig. 2 is a side view in the direction of arrow r in Fig. 1 illustrating axial displacement of the two roller actuators.

Fig. 3 shows, in a further embodiment, the two actuating members, which are of a common Levers are carried and are biased to by means of an additional spring device to avoid backlash with respect to the cam device.

Referring to Figure 1, a contact 1 is electrically isolated and using those known in the art Means attached to a fixed structure 2. Another, shown in its open position Contact 3 is arranged to come into engagement with contact 1 upon downward movement and further executes a grinding movement substantially at right angles to the first movement. The contact 3 is attached to a lever 4 which is rotatably connected to a lever 6 at 5 carrying an actuating roller 7 adapted to cooperate with a cam surface (not shown) serves. A compression spring 8 is arranged between the levers 4 and 6; and it goes without saying that the contact 3, when the two contacts 1 and 3 come into engagement with each other, executes a movement, which has a component at right angles to the opening and closing movement. The roller 7 is moved in accordance with the shape of the cam surface, whereby the lever 6 relative to the lever 4 and the pressure surface 8 is displaced. The rotary movement of the lever 4 below the force exerted by the spring 8 is limited by a stop 13.

Another actuating roller 9 is carried at the end of a lever 10. The two levers 6 and 10 are arranged rotatably about a common pin 11 and by a resilient one indicated at 12 Link firmly connected to each other. This member can be of known construction, e.g. Legs Spring device is used to once a slight resilient relative movement, as it is used for Neutralization of minor manufacturing defects is required and, on the other hand, a variable setting to allow the angular relationship between the jacks 6 and 10, with HiHe a usual (not shown) device, for example a propeller, and a counter spring can be obtained can. In order to close the contact by the first movement - in one of their two directions - The lever 6 is due to the interaction of the roller 7 with its associated (not shown cam surface rotated, in this case clockwise. The kinematics of the Mechanism is such that by the main part of the movement the contact 3 is in engagement with the fixed Contact 1 is brought and the spring 8 is compressed by the last part of the movement. Of the Lever 10, which is connected to lever 6 by link 12, moves in the same direction, wherein one of the roller 9 of the lever 10 associated separate cam surface is designed such that the aforementioned Movement of the lever 10 clockwise is made possible. This cam surface is also designed in such a way that that it rotates the lever 10 counterclockwise, which is necessary to make the contact 3 to be released from contact 1.

ίο As can be seen from Fig. 2, each of the two Lever 6 and 10 forked and comprises two side walls, one of which is bent so that the Rollers 7 and 9 are offset in the direction of the cam axis and the axis of the pivot pin II.

This axial displacement makes the use of coaxial but separate and diverse designed cam discs that work together with the two rollers 7 and 9, allows. If desired, the angular relationship of the two cam surfaces can be adjusted, and the Cam disks can be mounted with mutual overlap.

Since the cam surfaces, when they press against the rollers 7, 9, cause the lever links to rotate 4, 6, 10 in the clockwise direction as well as in the opposite direction, the roller 7 can also be used advantageously for controlling the contact closing movement while the roller 9 controls the opening of the contact. The spring 8, which is primarily used for the grinding movement is determined, also generates a contact pressure between the contacts 1 and 3. Thus, a Conventional (not shown) spring, which is used to generate a preload through contact pressure, relieved will; or you can do without it completely.

According to FIG. 3, in which like parts have like reference numerals, an embodiment is illustrated which is essentially similar to that in FIGS. 1 and 2. Here, however, instead of the levers 6 and 10, a single lever 6 a is used to carry the actuating rollers 7 and 9; and instead of the resilient connecting member 12 according to the first embodiment, a biasing element 12 a, for example composed of compression springs 14, 15, interacts with a bracket 16 connected to the lever 6 a and with a stationary support 17 which is attached to the fixed structure 2 or a Forms part of the same, whereby a backlash between the rollers 7.9 and their cam surfaces prevented and also the angular position of the lever 6 a with respect to the fixed structure 2 is resiliently maintained.

In one end position of the lever 6 a presses the lower end of the bracket 16 against the fixed support 17. It can also be seen that in this embodiment, the spring device 14, 15 biases the contact 3 in its open position, while the member 12 according to the the first-mentioned embodiment biases the contact 3 in its closed position. The springs 14, 15 are arranged in such a way that they counteract a backlash as desired without the load exerted on the camshaft being significantly increased. Since the biasing element consists of two springs 14, 15 which press against the outer surfaces of the parts 16, 17, and a rod 18 extends through the interior of the coil springs to apply pressure against the outer spring plates 19, 20

exercise, the characteristics of the entire spring arrangement can be designed essentially linear, so that the torque required by the drive camshaft is kept to a minimum.

The device described can be modified and varied in many ways within the framework of the essential ideas be designed. It is advantageous to use minor ones in order to eliminate manufacturing fluctuations Gaps, which are neutralized by the member 12 or 12 a, between the roles and to provide the cam surfaces cooperating with them. A weak one can serve the same purpose Spring of the roller 9 be mounted adjacent so that the backlash by light loading of the Roll 9 and thus the associated cam profile is added when the contact device is open is. When the roller 7 is moved by its cam to close the contacts and the To effect the grinding process, the weak spring partially compensates for the load, whereby ao the torque requirement is reduced.

Claims (4)

PATENT CLAIMS: 1. Cam-operated electrical contact device which has a stationary and movable contact piece, the movable contact piece (3) being carried by a rocker arm (4) biased by a spring (8), characterized in that first and second cam and cam follower devices ( 9, 7) are connected to the rocker arm (4) via levers (10, 6, 6 a) in order to produce two movements essentially in the same plane, but at right angles to one another, and that one movement serves to produce the movable contact piece (3) to open and close, while in a known manner the other movement causes the movable contact piece to slide on the stationary contact piece (1). 2. Contact device according to claim 1, characterized in that two of the two Lever (10, 6) carrying the cam follower are interconnected by a resilient member (12) are and that the rocker arm (4) is hinged to one of the two levers (6) such that it can rotate is that the other lever (10) via the first lever (6) and the resilient member (12) one Movement of the rocker arm generated. 3. Contact device according to claim 2, characterized by a compression spring (8) which arranged between the rocker arm (4) and the lever (6) to which it is articulated is. 4. Contact device according to claim 1, characterized in that one (7) of the two Cam and cam follower devices with respect to the other (9) displaced in the axial direction and that the mutual angular position of the cams can be regulated. Considered publications:
German patent specifications No. 732 881, 713 759. 1 sheet of drawings © 109 749/426 12.61