Work holding device

Claim 1

IN A WORKING HOLDING DEVICE FOR USE WITH ELECTROEROSION APPARATUS, THE COMBINATION COMPRISING: A GENERALLY CIRCULAR TABLE HAVING A DEPENDING PERIPHERAL SKIRT AND A PLURALITY OF NOTCHES IN SAID SKIRT; A CENTRAL POST SUPPORTING SAID TABLE; A BASE HAVING A HOLLOW BOSS UPSTANDING THEREFROM AND MEANS SUPPORTED AT THE UPPER END OF SAID HOLLOW BOSS FOR ROTATABLY ENGAGING AND SUPPORTING SAID TABLE; A GENERALLY CUP-SHAPED, UPWARDLY OPENING UPPER BRUSH PLATE SNUGLY EMBRACING AND FIXED TO THE LOWER END OF SAID POST AND HAVING A SUBSTANTIALLY PLANAR, LOWER ELECTRICAL TRANSFER SURFACE ARRANGED SUBSTANTIALLY PERPENDICULARLY TO THE AXIS OF SAID POST, SAID LOWER SURFACE BEING LOCATED BELOW AND UNDERLYING THE LOWER END OF SAID POST AND BEING OF AN AREA GREATER THAN THE AREA OF THE LOWER END OF SAID POST; A BUS BAR AFFIXED RIGIDLY WITH RESPECT TO SAID BASE AND HAVING AN OPENING THERETHROUGH; A LOWER BRUSH PLATE HAVING A STEM PORTION EXTENDING THROUGH SAID OPENING AND ARRANGED IN NON-ROTATABLE RELATIONSHIP WITH RESPECT THERETO, SAID LOWER BRUSH PLATE HAVING AT ITS UPPER END A SUBSTANTIALLY PLANAR ELECTRICAL TRANSFER SURFACE, SAID LAST-NAMED SURFACE BEING SIMILAR IN SIZE AND SHAPE, AND BEING IN CONTACT WITH, SAID FIRST-NAMED ELECTRICAL TRANSFER SURFACE; MEANS RESILIENTLY URGING SAID LOWER BRUSH PLATE AGAINST SAID UPPER BRUSH PLATE FOR URGING SAID ELECTRICAL TRANSFER SURFACES RESILIENTLY TOGETHER; WHEREBY THE ONLY RESPECTIVELY MOVABLE SURFACES THROUGH WHICH ELECTRIICAL CURRENT IS TRANFERRED FROM ONE BODY TO ANOTHER ARE OF LARGE AREA AND CAPABLE OF A CONFORMING IN A SNUG AREA CONTACT WITH RESPECT TO EACH OTHER.