Patent GB-354725-A (GB)
Title: Improvements in or relating to screw milling machines
IPC: B23G1/32
Filed: 1930-05-12
Abstract: 354,725. Milling screws. BAMBRIDGE, W. G., Regent Street, Kettering, Northamptonshire. May 12, 1930, No. 14548. [Class 83 (iii).] The work-carrying spindle 10 and cutter shaft 8 of a screw milling machine are mounted in parallel bearings 1, 2 formed in frames 3, 4 which are pivotally connected by a common rod 5, and the bearings are connected by a screw coupling whereby the relative lateral position of the two bearings can be adjusted. This coupling comprises a headed rod 59 having right- and left-hand threads engaging diametral tapped holes in cylindrical blocks 58 loosely mounted in lugs 56, 57 on the bearings. A quadrant 62 pivoted on the bearing 1 has a slot 65 engaging a pin 66 fixed in lugs 67 on the bearing 2, the quadrant being provided with indicia co-operating with markings on the lugs 67 so as to facilitate adjustment. A handle 68 working on the screwed end of the pin 66 may be turned so as to bind upon the adjacent lug 67 to lock the bearings after adjustment. The spindle 10 has a threaded part 39 engaging a thread 40 in the bearing 1, whereby axial feed motion is imparted to the spindle as it rotates. In a power-operated machine for screwing pipes or tubes externally, the rod 5, Figs. 1 and 3, is fixed in lugs 6 on a stand 7, the frame 4 being also secured to the rod. An electric motor 13 is carried by arms 11, 12 fixed to the ends of the rod 5 and a pinion 14 on its shaft drives a gear 21 on the cutter shaft through gears 15, 17, 18 carried by the arm 12. A gear 22 mounted freely on the rod 5 and meshing with a gear 19 integral with gear 17 has formed integral therewith a worm 23 driving a worm wheel 26 on an intermediate shaft 25 carrying a worm 27 adapted to be engaged with a worm wheel 24 on the spindle 10 for driving the latter. The shaft 25 is journalled in a housing 28 pivotally mounted on the rod 5 so that by allowing the housing to swing down the worm 27 is disengaged from the wheel 24. This downward movement is limited by a pin 35 projecting from the housing through a hole 36 in an arm 33 secured to the bearing 1, and the housing is adapted to be retained in raised position by a spring-pressed tapered member 37 on the pin 35 adapted to engage in the hole 36. In a hand-operated machine, the shaft 8, Figs. 5 and 7, is provided with a driving handle 79, and a worm 75 on the shaft engages a worm wheel 76 feathered on a shaft 74 slidably mounted in brackets 72, 73 swinging on the bearings 1, 2, while a worm 77 feathered on the shaft 74 engages a worm wheel 78 adapted to be clutched to or declutched from the spindle 10 by a sliding key 81 or by a dog clutch. In this form of machine, one of the bearing frames 3, 4 may be held in a vice or the work may be so held, in which latter case the machine revolves around the work. When dealing with stock or small pipes or tubes which necessitate an external chuck, the bearing 1 is arranged to one side of the bearing 2, and both are mounted on a common tubular rocker bar through which runs a longitudinal shaft driven from the cutter shaft at one end and at the other end driving the carrier spindle. The screw coupling between the bearings is in this case arranged between the bearing frames. Mandrels.-The pipe or tube 45 to be screwed is gripped interiorly by two series of pins 47 slidable in radial holes at the ends of an extension 46 of the spindle 10 and adapted to be projected outwardly by conical members 48 which are moved axially within the extension 46 by a rod 49 having right- and left-hand threads 50, 51. The rod 49 is furnished with an operating handle 54, and the pins are frictionally held in position by springs 55.