Torque control adaptor for ratchet wrench

Claim 1

A torque adaptor for a ratchet driven socket wrench comprising, iN combination: a housing having inner and outer cylindrical members threadably joined for selected axial movement, each of said inner and outer members having one end wall and one open end to define an enclosed chamber therebetween, the end wall of said outer member having an opening therethrough and the end wall of the inner member having an outwardly directed non-circular centrally located axial extension output shaft, and a set screw threadably received in an opening in the in the cylindrical wall of said outer member, said set screw being adapted to be tightened against the cylindrical wall of said inner member to selectively fix the axial relationship of said inner and outer members, a friction disc anchored to the inner surface of the end wall of the inner housing member, said friction disc having a surface of wave form configuration along a peripheral area on the face of the disc which is exposed to said enclosed chamber, said friction disc having an outer diameter substantially equal to the inner diameter of the inner housing member, and said friction disc having a central cup-shaped recess defined therein, a drive element having a drive disc slidably mounted thereon at one end in abutting relationship with said friction disc and a reduced diameter shaft portion at the opposite end thereof protruding into the opening in the end wall of said outer housing member, the end of said shaft portion which protrudes into the opening in the end wall of the outer housing member having a recess of square cross-section adapted to releasably receive a square shaft on a ratchet driven wrench, spline means operatively coupling said drive disc and said drive element, said drive disc having a surface of wave form configuration along a peripheral area on the face thereof which abuts the friction disc so that the wave form surfaces on the friction disc and drive disc are in abutting face-to-face relationship, the end of said drive element adjacent said drive disc having a terminal end sized for bearing reception in the central cupshaped recess in said friction disc for transmitting axial forces directly between said drive element and said axial extension shaft, a compression spring surrounding the shaft portion of the drive element in concentric relationship therewith, said compression spring abutting said drive disc at one end and the end wall of said outer housing member at the opposite end to bias said drive disc against said friction disc whereby rotative torque movement applied to said drive element effects corresponding rotative torque movement of the axial extension shaft on the housing until the torque applied to said drive element overcomes the spring compression thereby allowing the drive disc and friction disc to rotate relative to each other, means rotatably securing said drive element terminal end within said friction disc central recess for preventing axial separation of said drive element terminal end from said friction disc while permitting relative rotation therebetween, and a calibrated scale on a external surface of said outer housing member and a calibrated scale on an external surface of said inner housing member, said calibrated scales being adapted to cooperate in visually displaying the relative relationship of the inner and outer housing members whereby the compression spring can be adjusted selectively to determine the desired rotative torque between said friction disc and said drive disc independently of axial forces applied between said drive element and said axial extension output shaft.