Remotely controlled electric switch

Claim 1

A remotely controlled pneumatically operated electrical switch, comprising: a pneumatic actuator; a mechanical switch assembly; and pneumatic tubing extending between said pneumatic actuator and said mechanical switch assembly, wherein said mechanical switch assembly comprises - a housing made of electrically non-conductive material having first and second contact blades extending therefrom, first and second slot recesses for receiving contact blades of an electric plug of a device to be switched, and a contact in the second slot recess in contact with the said second extending contact blade, a plunger rod operable by said pneumatic actuator by way of said pneumatic tubing, a cam wheel made of electrically non-conductive material rotatably carried by said housing and adapted to be rotated by said plunger rod, said cam wheel having a cam with sequentially high and low cam surfaces, an electrically conductive spring arm having one end in electrical contact with a contact provided in said first slot recess, a first electrical contact point on the end of said spring arm opposite that end in electrical contact with said first slot recess, and a second electrical contact point in electrical connection with the said first extending contact blade, wherein said spring arm is spring biased away from contact between the said first and second electrical contact points and bears against said cam provided on said cam wheel, whereby rotation of said cam wheel moves said first electrical point into and out of contact with said second contact point.