Patent Application
20060220779
The present invention relates to a safety switch including an adjusting assembly connected to the bimetallic plate so as to ensure that the bimetallic plate is deformed as desired when overload.
A conventional switch device, especially for those switches using bimetallic plate to prevent from being burn when an overload is happened, generally includes a bimetallic plate which is deformed when overload so as to separate the two contact points respectively located on the bimetallic plate and one of the two terminals. Some inherent shortcomings for these conventional safety switch devices are found. There are too many parts involved in the safety switch device and a longer period of time is required when assembling the switch device, this increases the cost of the products. The parts might be arranged inaccurately and affects the deformation of the bimetallic plate. Once the bimetallic plate is deformed to cut off the circuit, because of the improper arrangement of the parts as mentioned above, the bimetallic plate could deform to re-connect the two contact points to connect the circuit again. Because the inaccuracy of the deformation of the bimetallic plate, the switch member does not set the “OFF” position after the bimetallic plate is deformed to cut off the circuit.
Therefore, it is desired to have a safety switch wherein the bimetallic plate is ensured to have proper flexibility and deformed to separate the two contact points when overload.
In accordance with an aspect of the present invention, there is provided a switch device that comprises a body with a top opening with which a switch member is pivotably engaged, two slots are defined through an underside of the body so that a first terminal and a second terminal respectively extend through the two slots. A first contact point is connected to the second terminal. A bimetallic plate has a first end fixed to the first terminal and a second contact point is connected to an underside of a second end of the bimetallic plate. The second contact point is located above the first contact point. A link has an upper end pivotably connected to the switch member and a lower end of the link clamps the second end of the bimetallic plate. An adjusting assembly includes a connection member fixedly connected to an inside of the body and an adjusting member movably extends through a wall of the body and contacts the connection member. A biasing member has a first end connected to the second end of the bimetallic plate and a second end of the biasing member is connected to the connection member.
The main object of the present invention is to provide a safety switch that uses an adjusting assembly, which adjusts the curvature of the biasing member so that the bimetallic plate is ensured to be deformed toward desired direction to cut the circuit.
Another object of the present invention is to provide a safety switch that includes less number of parts so as to have lower manufacturing cost.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
Referring to the drawings and in particular
A link includes an upper end which is pivotably engaged with the receiving hole 221 in the protrusion 22 of the switch member 2 and a lower end of the link 3 includes two bars between which a space 32 is defined. The second end of the bimetallic plate 4 is clamped in the space 32.
An adjusting assembly 5 includes a connection member 51, a connection member 51, a biasing member 53, and an adjusting member 52. The connection member 51 is an E-shaped member and the upper and lower extensions of the E-shaped connection member 51 are engaged with the slits 17 and the adjusting member 52 such as a bolt movably extends through the through hole 16 and contacts the connection member 51. The biasing member 53 is a U-shaped plate and the first end of the biasing member 53 includes a through hole 531 and the second end of the bimetallic plate 4 includes a tongue 42 which is engaged with the through hole 531. A second end of the biasing member 53 is inserted in the engaging slit 511 of the connection member 51.
As shown in
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
