A universal grinding and backing off grinding apparatus for twist drills, screw taps, centre punches, lathe centres and the like

摘要

385,746. Grinding. WEISSINGER, J., 33, Moltkestrasse, Esslingenon- Neckar, Germany. Dec. 30, 1931, No. 36005. [Class 60.] Twist drills, sharpening; cutting-edges, shaping. -Apparatus for grinding and backing off twist drills, taps, &c. and for grinding centre punches &c., and adapted to be fitted on an existing grinding-machine or on a lathe, comprises a hollow spindle 2, rotatable by a handle 13 and provided with means for gripping the work, mounted in bearings 3, 4 in a casing 1, the bearing 4 being pivoted to the casing at 7 and the bearing 3 being guided by a screw 6 moving in a slot 5 in the casing. The spindle is pressed by a spring 8 to press a selected cam 12, 12a, or 12b against the point 10 of a screw 11 having graduations 28 to allow setting of the spindle and depth of grinding by a grinding-wheel 17, the screw being carried by a slide piece 52 so adjustable as to bring the point 10 into register with the desired cam. In order to set the cutting-edges of the work in register with the cams a latch 19 is provided adapted to engage a hole 38 in the handle 13, thereby locking this, and a slidable abutment 25 is provided adapted to engage the cutting-edge of the work. The casing has a hollow bracket 29 whereby the apparatus is mounted on a bolt 30 clamped to a support of the grinding-machine, and may be moved to two positions, one for grinding and the other for removal &c. of the work, determined by the contact of faces 34, 33 respectively of the bracket with a pin 32 mounted in the bolt 30 ; a screw 36 serves to clamp the apparatus in the two positions. In order to give the requisite axial motion to a drill, and to prevent rotation in the wrong direction, two pivoted latches 39, 40 are mounted on the casing, their pivots having stops 43, 44 to engage respectively a cam 45 for right-handed drills, and a cam 46 for lefthanded drills, the spindle being pressed axially by a spring 47 ; the latches are locked by screws 49, 50 and may be set so as to allow of rotation of the spindle in both directions to allow of grinding centre punches &c. A plate 48 is provided to allow of setting the apparatus to any desired angle of grinding.