Electricity: circuit makers and breakers – Electric switch details – Actuators
Patent
1985-03-28
1986-11-04
Marcus, Stephen
Electricity: circuit makers and breakers
Electric switch details
Actuators
200144B, 403131, 403 76, H01H 3366, H01H 346
Patent
active
046211756
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a drive for a vacuum switch with joint parts arranged between its movable contact bolt and a drive lever which actuates the latter and is supported in a stationary manner for transmitting the actuating force to a switching tube; which are provided with central holes for the passage of the movable contact bolt of the switching tube and which have a spherical segment as well as a spherically shaped joint socket adapted thereto, where the center of the sphere of the segment is arranged offset in the direction of the switching tube from the center line of the drive lever extending at right angles to the axis of the contact bolt.
UNDERLYING STATE OF THE ART
A drive of this type has become known through a publication of the firm Sace, Bergamo, Italy with a designation CAT 8-0/12-1980. The parts of the joint make possible a relatively low-wear introduction of the actuating force from the drive lever to the movable contact bolt of the switching tube, where, however, transverse forces direction cross-wise to its longitudinal axis are exerted on the movable contact bolt. In order to insure proper functioning of this joint arrangement it is necessary to carefully align the movable contact bolt and the bore of the joint parts. To this end, the switching tube is pivoted at its fixed contact bolt likewise with joint parts in the manner of a ball joint.
With unfavorable tolerances between the fixed and the movable contact bolt, even additional transverse forces can be introduced into the movable contact bolt by the necessary alignment of the switching tube. In spite of the relatively high cost of two ball joints per switching tube, the occurrence of forces cannot be prevented which cause wear and shorten the service life of the vacuum switch.
A ball joint for fastening the switching tube of a vacuum switch to its stationary contact bolt is described in detail in British Pat. No. A2 095 476.
While it is known that switching tubes in vacuum switches can also be fastened rigidly (U.S. Pat. No. 3,267,247) and specifically in conjunction with a drive which comprises, similarly to the arrangement mentioned at the outset, a pivoted drive lever which is stationary and a body with a spherical working surface, this working surface interacts with a plane countersurface of the drive lever, where friction, wear and the occurrence of transverse forces between the driver lever and the movable contact bolt are unavoidable.
Starting from a vacuum switch of the type mentioned at the outset, it is an object of the invention to describe a drive in which the switching tube and its movable contact bolt as well as the drive lever operating the same are relieved of stresses by transverse forces during the switching motions, wherein the service life of the drive lever as well as of the switching tube is increased without expensive means.
DISCLOSURE OF THE INVENTION
According to the invention, this problem is solved by the provision that the distance of the center of the sphere from the center line of the drive lever corresponds approximately to one-half of the stroke of the contact bolt in switching on and off. With this position of the center of the sphere, the relative displacement between the drive lever and the movable contact bolt becomes a minimum of such small size that the offset can be neglected under practical conditions. This eliminates the necessity of a hinged or alignable fastening of the switching tube. It is merely necessary to see to it that the movable contact bolt and the drive lever are aligned with respect to each other free of forces in the rest position.
The distance of the center of the sphere from the center line can deviate from the exact value (one-half of the stroke of the movable contact bolt) within the usual tolerances. It can also be taken into consideration here that the stroke of the switching tubes can become somewhat larger in the course of their life.
The passage of the movable contact bolt without force through the joint arrangement can advantageously be achiev
REFERENCES:
patent: 1875575 (1932-09-01), Eckhard
patent: 2984249 (1961-05-01), Sears, Jr. et al.
patent: 3214550 (1965-10-01), Easley
patent: 3267247 (1966-08-01), Ross
patent: 3501180 (1970-03-01), Waara
SACE publication, Bergamo, Italy, VRC Medium Voltage Vacuum Contactors, CAT 8-0/12-1980.
Luebke Renee S.
Marcus Stephen
Siemens Aktiengesellschaft
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