Variable resistors

Claim 1

AN ELECTRICAL INSTRUMENT COMPRISING: A GENERALLY HOLLOW METALLIC HOUSING MEMBER; SUPPORT MEANS, COMPRISING A METALLIC SUPPORT MEMBER, HAVING END WALL MEANS AND POSITIONED WITHIN SAID HOUSING MEMBER IN CLOSE CONTACT WITH THE HOUSING MEMBER OVER A CONSIDERABLE AREA OF THE INTERIOR OF THE HOUSING MEMBER TO FACILITATE HEAT TRANSFER THEREBETWEEN; OTHER MEANS, INCLUDING A RESISTANCE ELEMENT AND ELECTRICAL RETURN MEANS, MOUNTED ON SAID WALL MEANS; MEANS, INCLUDING A SHAFT MEANS , SUPPORTED BY SAID WALL MEANS AND EXTENDING TO THE EXTERIOR OF SAID HOUSING; MEANS, INCLUDING A CONTACT MEMBER RESILIENTLY ENGAGING SAID RESISTANCE ELEMENT, ENGAGING SAID SHAFT MEANS FOR MOVEMENT THEREBY AND ELECTRICALLY CONNECTING SAID ELECTRICAL RETURN MEANS WITH SAID RESISTANCE ELEMENT AND CONSTRUCTED AND ARRANGED TO BE MOVED TO MOVE SAID CONTACT MEANS ALONG SAID RESISTANCE ELEMENT IN RESPONSE TO MOVEMENT OF SAID SHAFT MEANS; MEANS INCLUDING RESPECTIVE ELECTRICAL LEADS CONNECTED TO SAID RESISTANCE ELEMENT AND SAID ELECTRICAL RETURN AND EXTENDING TO THE EXTERIOR OF SAID HOUSING MEMBER; AND MEANS SEALING THE INTERIOR OF SAID HOUSING MEMBER AGAINST INGRESS OF FOREIGN MATERIAL.