Electricity: circuit makers and breakers – Special application – Liquid or moisture responsive
Patent
1983-09-19
1986-12-16
Marcus, Stephen
Electricity: circuit makers and breakers
Special application
Liquid or moisture responsive
H01H 2142
Patent
active
046298380
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electrical engineering, and more specifically concerns microswitches.
2. Description of the Prior Art
The accuracy in operation of automatic lines and production control systems depends to a great extent on the sensitivity of microswitches used therein, which microswitches must be accurate in transmission of information. Errors caused by the microswitches during their service are difficult to eliminate practically.
The movable contacts in the microswitches are actuated preferably with the aid of metal plates capable of responding to the changes in temperature or pressure, which plates when being tensed or compressed undergo only a slight bending. Therefore, one of the main characteristics of a microswitch is the sensitivity thereof determined by the length of the movement path of the actuating link (the shorter is the travel path required for operating a movable contact element the higher is the sensitivity of the microswitch), and hence by the quantity of energy required for such microswitches to operate, that is to make or break contacts. An important requirement imposed on microswitches is that they must provide reliable and trouble-free switching under conditions wherein they are exposed to vibrations and shocks even at a low speed of movement of the actuating link. This requirement is determined by the contact resistance which depends on the contact pressure, which contact pressure also determines the resistance of a microswitch to vibration and shocks arising during operation.
U.S. Pat. No. 1,098,074 discloses a microswitch featuring a high sensitivity. This microswitch comprises an insulating base 1' (see FIG. 1), stationary contacts 2', 3' secured on said base 1', a movable contact 4', and a three-link system 5' of levers adapted for selectively changing the position of the movable contact 4'. The three-link system 5' of levers comprises an actuating link 6', an intermediate link 7', and a contact link 8', said links being connected therebetween in series. The actuating link 6' and the contact link 8' are fastened on the insulating base 1' for rocking, with the movable contact 4' fastened on the contact link 8', and one of said links, for instance intermediate link 7' being made elastic.
When the microswitch is in its initial position, the intermediate link 7' which is preliminarily tensed acts on the end of the contact link 8' with a force P. A normal force P.sub.1 to produce a contact pressure is P.sub.1 =P.multidot. sin .alpha., where .alpha. is an angle between the contact link 8' and the intermediate link 7'.
Under the action of an external force F' the actuating link 6' is caused to displace and the intermediate link 7' changes its position relative the contact link 8', in which case the angle .alpha. decreases as a result of which the contact pressure P.sub.1 respectively decreases. When the actuating link 6' reaches the position of direct operation of the microswitch (that is, when point A reaches line I--I which is a line of unstable initial state of the contact link 8', to take a position A.sub.1), the angle .alpha. and the contact pressure P.sub.1 are equal to "0" (zero).
Shown in FIG. 2 is a contact pressure graph showing a contact pressure variation depending on the movement path of the actuating link 6', where 1 is the path described by a point A of the actuating link 6'.
As the actuating link 6' moves further and the point A intersects the line I--I, the contact 4' is caused to switch over at its natural speed of motion, in which case the actuating link 6' with the point A may reach a position of overtravel (position A.sub.2).
When the external force F' does not any more act on the actuating link 6' the latter under the action of the spring moves so that the point A reaches the line II--II, which is a line of an unstable changed position of the contact link 8' (position A.sub.3).
Differential travel L.sub.A of the actuating link 6' at the point A is equal to the distance between the points A.sub.1
REFERENCES:
patent: 2189996 (1940-02-01), Riche
patent: 2573588 (1951-10-01), Miller
patent: 2821588 (1958-01-01), Fisher
patent: 2971069 (1961-02-01), Good
patent: 3210497 (1965-10-01), Schwartz
patent: 4050046 (1977-09-01), Wilson
Chaly Fedor P.
Filatov Nikolai I.
Kosovtsev Vladimir A.
Mironenko Vyacheslav G.
Poltorak Alexandr P.
Luebke Renee S.
Marcus Stephen
Tekhnologichesky Institut Vzryvozashischennogo I Rudnichnogo
LandOfFree
Sensitive constant contact pressure microswitch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sensitive constant contact pressure microswitch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sensitive constant contact pressure microswitch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-245910