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GB Patent: GB-540,796
An Automatic Screw-thread-cutting Machine
George Adcock - Leicester, England
Howard Shipley - Leicester, England

USPTO Classifications:

Tool Categories:
metalworking machines : metal threading machines


Adcock & Shipley, Ltd. - Leicester, England

none listed

Patent Dates:
Applied: Apr. 29, 1940
Granted: Oct. 30, 1941

Patent Pictures:
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"Vintage Machinery" entry for Adcock & Shipley Ltd.
An automatic screw thread cutting lathe particularly for cutting threads in nuts has means for giving repeated relative traverses between tool and work, the tool being withdrawn laterally from the cut at the end of a cutting traverse, returned idly and restored to take a deeper cut at the beginning of the succeeding cutting traverse. The work holder 10 is mounted on a lead screw 11 running in a nut 12 secured to the fixed headstock 13, the lead screw being driven from a cross shaft 15, worm gearing and a reversing electric motor or reversing gearing (not shown) to reciprocate the work past the tool 24. The shaft 15 also drives a countershaft 17 which through a friction clutch 18 drives an oscillating feed cam 20 actuating the tool holder 22. At the end of each cutting traverse the cam is rotated to withdraw the tool for the idle return movement of the work and at the end of the return the cam is rotated in the reverse direction through a larger angle to apply the cut. The shaft 19 carries a disc 27 fitted with a pin 28 which on reversal at the end of the cutting traverse is moved to engage a fixed stop 25, the clutch 18 then slipping. At the end of the idle stroke, reversal of shaft 19, causes a second pin 29 on the disc 27 to engage a movable stop 26 after which the clutch again slips. The stop 26 is carried on a pair of loose oppositely-toothed ratchet wheels 30 operated by a pawl 33 on a carrier 31 rocked at the end of each idle stroke by a pivoted cam 36 carried by a sliding part 38. A ramp 35 on the carrier disengages the locking pawl 34 to permit this movement. The upper slide 22b carrying the tool bar is adjustable by a screw 40 on a lower slide 22a, both slides being carried by a lognitudinally-adjustable member. The cam 20 maybe shaped to apply heavy cuts for the first few strokes and thereafter progressively lighter cuts. Indexing mechanism may be provided for cutting multi-start threads. A counting device 43 may be arranged to stop the machine after a predetermined number of traverses.

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