Patent GB-330507-A (GB)
Title: Machines for boring metal
IPC: B23Q1/68
Filed: 1929-02-09
Abstract: 330,507. Automotive Engineering Co., Ltd., and Longley, H. J. Feb. 9, 1929. Boring; boring-heads.-In a machine for boring metal, provision is made for withdrawing the cutter radially from the work at the commemcement of its axial retractive movement and for restoring the cut when the cutter is moved axially towards the work. In one form the cutters 18, Fig. 1, are carried by a bar 5 which is radially adjustable in a spindle 4 by means of eccentric, sleeves 21, 25 mounted in an eccentric, bore in the end of the spindle. Rotation of the sleeve 25 relatively to the spindle is presented by a transverse, pin 28 and rotation of the sleeve, 21 is provided for by a graduated collar 22 having tommy-holes 23 accessible, through an aperture, 31. in a cap 30 screwed on the spindle. Cones 6, 7 are attached to and formed integral with the spindle respectively and a double coned bush 11 is attached to its other end.The cones are supported in corresponding bushes 8, 10, 16, 17, the axes of corresponding cones 6, 7 and 13, 14 or of bushes 8, 10 and 16, 17 being eccentrically arranged so that on withdrawing the spindle axially the cutters will be retracted radially to the position shown whilst on feeding axially relative axial and radial movement between the cones and bushes will take place to restore the cut. The hushes are carried bv a sleeve 3 rotatably mounted in bearings 2 and rotation of the spindle 4 relatively to the sleeve 3 is prevented by a collar 77 attached to the spindle and pins 79 attached to the sleeve. In a modified form the cones and bushes are replaced by cylindrical or square &c. portions 32, 33, Fig. 3, on the spindle 4 arranged obliquely as shown and slidable axiallv in guide, bushes 36, 37 which are carried by the sleeve 3, the latter being rotated in the bearings 2 by a pulley 54. The spindle may be adjusted axially in the guide bushes to determine the depth of cut by means of a sleeve 41 screwing on the exterior of the sleeve 3 and having an internal flange 42 engaging between collars 46, 47 attached to the spindle. The, sleeve 41 is split and clamped to the. sleeve 3 by a coned nut 45. The flange 42 has axial play between the collars 46, 47 to allow movements. of the spindle relatively to the sleeve under control of a feeding lever 49 and a cam 53. The, lever first causes radial movement of the cutters and then axial feeding movement of the spindle and bearings on a guide bar 56. The collar of the sleeve 41 may be graduated to form a micrometer adjustment for the cutters. In a further modification, for use when the work instead of the spindle, is fed axially, the spindle 4, Fig. 4, is screwed at 58 to receive a graduated bush 59, and is split to receive an expanding locking plug 60. An extension 65 of the sleeve 3 forms an abutment for a spring 70 which normally forces the spindle to the right in Fig. 4 under control of the adjustable bush 59, and an outer sleeve 61 is splined to the extension 65 at 67 and receives the yoke 63 of a lever similar to the lever 49 in Fig. 3. The lever may be operated by a cam in synchronism with the feeding and withdrawal of the work. In another modification the sleeve 3, Fig. 1, extends beyond the rear bearing 2 and is provided with a toothed clutch member slidably keyed thereon whilst the spindle, 4 has a driving pulley slidably keyed thereon and kept at a fixed distance from the bearing 2. The clutch is normally pressed by a spring into engagement with clutch teeth on the pulley so that the members 3 and 4 rotate together as in Fig. 1, but a hand operated cam is provided to disengage the clutch from the pulley and press a friction surface thereon into engagement with a similar surface on the bearing 2, whereupon the sleeve 3 remains stationary and the spindle 4 is rotated by the pulley about a fixed axis whose lateral position may be determined by rotating the clutch and sleeve 3 (by hand) relatively to the bearing prior to engagement of the friction surfaces.