Thread milling apparatus

• US 4,034,646 A
• Filed: 06/25/1975
• Issued: 07/12/1977
• Est. Priority Date: 06/26/1974
• Status: Expired due to Term

• Current Assignee: Automatindustrier I Gavle AB
• Original Assignee: Automatindustrier I Gavle AB
• Inventors: Dahlin, Gunnar
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Briggs, William R.
• Application Number:
  US05/590,167
• Time in Patent Office: 748 Days
• Field of Search: 90/11.4, 90/11.42, 90/11.64, 90/11.6, 90/11.62, 90/11.66
• US Class Current: 409/76
• CPC Class Codes: B23G 1/34 with a cutting bit moving in a closed path arranged eccentrically with respect to the axis of the rotating workpieces
• CPC Class Codes: Y10T 409/300672 with means to rotate work and means to interrelatedly infeed the work relative to the cutter

Abstract

An apparatus for cutting threads or grooves in a rotating workpiece with a rotating cutting tool, the tool and workpiece rotating in timed relationship, comprising an integer ratio between the revolutions of tool and workpiece and a superimposed rotation of tool or workpiece relative the other, which superimposed rotation is coupled to the feeding motion for tool or workpiece, the tool being arranged for rotation about an axis located outside the contour of the thread to be cut in the workpiece.

Claims

1. An apparatus for milling threads on a workpiece comprising a rotatably mounted workpiece holder, a cutting tool mounted adjacent said holder for rotation about an axis which is inclined in a vertical plane relative to the axis of rotation of said workpiece holder, horizontal projections of said two axes of rotation being longitudinally displaced from and substantially parallel to one another, the axis of rotation of said tool being located completely outside the contour of the thread that is to be milled on a workpiece carried by said holder, drive means rotating said workpiece holder and said cutting tool and conrolling the respective rotational speeds of said holder and said tool in integer ratio to one another, and feeding means effecting relative translational motion of said rotating holder and rotating cutting tool in directions along their respective axes of rotation, said feeding means including means operative to superimpose a supplemental rotary motion proportional to the rate of said relative translational motion on one of said rotating workpiece holder and rotating tool, said rotatably mounted workpiece holder comprising an elongated cylindrical spindle mounted for rotation, an elongated cylindrical workpiece carrier supported by said spindle in coaxial relation thereto, said workpiece carrier having means for fixedly securing a workpiece thereto, said carrier including a lead screw in thread engagement with said spindle, said feeding means including means for turning said lead screw relative to said spindle to effect relative axial movement between said spindle and carrier.

2. The apparatus of claim 1 wherein said spindle includes a bore along its axis of rotation, said cylindrical workpiece carrier being disposed within said bore and having said lead screw on its exterior surface in thread engagement with facing interior threads on said bore.

3. The apparatus of claim 1 wherein said feeding means includes a rod coaxial with said spindle at a position rearward of said carrier, said rod being coupled to said workpiece carrier by splines operative to prevent relative rotation between said rod and said carrier while permitting relative axial motion between said rod and said carrier, and means for moving said rod along the axis of said spindle and carrier.

4. The apparatus of claim 1 wherein said last-named means comprises a hydraulic cylinder having a piston therein, said rod being connected to said piston.

5. The apparatus of claim 4 wherein said spindle includes means defining a helical groove, said rod having an outstanding pin disposed in said helical groove operative to effect rotational movement of said spindle relative to said carrier as said rod is moved axially to produce said supplemental rotary motion.