US2911771A

US2911771A - Apparatus for sharpening drills by means of a grinding wheel

Info

Publication number: US2911771A
Application number: US680728A
Authority: US
Inventors: Amiet Oscar
Original assignee: Christen & Co A G
Current assignee: Christen & Co A G; Christen & Co AG
Priority date: 1956-09-28
Filing date: 1957-08-28
Publication date: 1959-11-10
Anticipated expiration: 1976-11-10

Description

0. AMIET Nov. 10, 1959 APPARATUS FOR SHARPENING DRILLS BY MEANS OF A GRINDING WHEEL Filed Aug. 28, 1957 2 Sheets-Sheet 1 0. AMIET Nov. 10, 1959 APPARATUS FOR SHARPENING DRILLS BY MEANS OF A GRINDING WHEEL Filed Aug. 28, 1957 2 Sheets-Sheet 2 MEEEE A M FIG 3 United States Patent APPARATUS FOR SHARPENING DRILLS BY MEANS OF A GRINDING WHEEL Oscar Amiet, Geneva, Switzerland, assignor to Christen & Co. A.G., Bern, Switzerland, a Swiss firm Application August 28, 1957, Serial No. 680,728

Claims priority, application Switzerland September 28, 1956 3 Claims. (Cl. 51-219) My invention has for its object an instrument for sharpening drills by means of a grinding wheel. Said apparatus is characterized by a carrier for the front end of the drill, said support being fitted revolu-bly over a pivot parallel with the axis of the grinding wheel and located in the immediate proximity of the latter while a carrier for the rear end of-the drill is also carried revolubly on said pivot through the agency of an arcuate slider adapted to move with a view to adjusting the cutting angle over a drum, mounted revolubly around a rod extending radially of the pivot, to provide adjustment of the angular setting of the drill.

I have illustrated by way of example a preferred embodiment of my invention together with a detail modification in the accompanying drawing, wherein:

Fig. l is a perspective view of the apparatus;

. Fig. 2 is a sectional view thereof through the axis of the grinding wheel;

Fig. 3 is an elevational view of a detail on an enlarged scale;

Fig. 4 is a view of a modification of said detail shown in Fig. 3.

The apparatus illustrated is particularly suitable for the sharpening of drills the diameter of which ranges between 0.1 and 2 mm. It includes a support 1 fitted on an upright 2. A shaft 3 carrying at one end a bellshaped grinding wheel 4 is revolubly carried inside a socket 5 rigidly secured inside the support or head-stock 1.-' The position of said socket is longitudinally adjustable and it is secured in position by a screw 6 threadedly engaging the support and the end of which bears against the bottom of the longitudinal groove 7 formed in the socket. The shaft 3 is fitted inside the socket 5 with some axial clearance and its rear end engages a stop which is adjustable in an axial direction, said stop being constituted by a screw 8 engaging said rear end and screwed inside a stationary support 9, said screw being locked in its turn by a further screw 10 (Fig. 1). The axial location of the grinding Wheel may thus be adjusted in a manner such as will compensate for its wear. The shaft 3 carries furthermore a grooved pulley 11 driven by a motor which is not illustrated.

The drill is fitted on the apparatus through the followingmeans: a lug 1a of the head-stock 1 is provided with a pivot 12, the axis of which is parallel with that of the grinding wheel. A sleeve 13 is revolubly mounted on said pivot with the interposition of a ball bearing 14. Said sleeve carries radially on the one hand a carrier 15 for the front end of the drill and on the other hand a rod 16. The carrier 15 is provided with two orthogonal bearing

surfaces

15a and 15b (Fig. 3), the axis of the rod 16 lying in the plane of the surface 15b perpendicularly to the axis of the pivot 12.

A drum 17 is revolubly carried by the rod 16. The outer surface of said drum forms a part cylindrical slideway the axis of which extends radially of the rod 16 and over which may rock the arcuate slider 18 provided with a slot 19 through which the rod 16 extends.

Said rod the outer end 16a of which is threaded carries a nut 20 which serves for locking in position the drum 17 and the slider 18 after adjustment. Said nut 20 which is longitudinally elongated is outwardly knurled so as to form also a handle controlling the movements of the drill with reference to the grinding wheel. The arcuate slider 18 carries at one end a bracket 21 (Fig. 1) on which is fitted a stud 22 engaging the axial bore inside a chuck 23 carrying the drill'24. Said stud forms the end of a screw 22a provided with a knurled control shank 22b and a scale-carrying drum 22c moving past a stationary mark 25. The axial position of the stud 22 and consequently that of the chuck may thus be adjusted in a highly accurate manner. The chuck includes two sections 2311 and 23b which are telescopically assembled and are locked axially with reference to each other by means of a screw 26. The chuck is removably fitted on the apparatus and it is held in position on the one hand by the drill resting through its front end in the carrier 15 and on the other hand by the stud 22 engaging its rear axial recess which is not illustrated. The rear section 2312 of the chuck is provided with an enlarged part 230 forming a divider. To this end, two diametrically opposed notches. 27 are formed in said extension for engagement by the end of a catch 28 sub jected to the action of a return spring carried by the bracket 21. Said catch defines thus two stable angular positions for the chuck 23, said positions lying at from each other and corresponding to the two operative cutting surfaces of the drill. It is also possible to provide a larger number of notches 27 when sharpening drills having more than two cutting surfaces.

The apparatus operates as follows: the drill is introducedinto the chuck and locked therein and the chuck is then set in position in the apparatus. The length of the chuck is adjusted through a sliding of its section 23a with reference to its section 2312 after which the screw 26 is screwed in when the drill rests near its front end over the carrier 15. The adjustment of the axial position of the drill may be perfected through the agency of the screw 22a. Before the screw 26 is actually tightened, the section 23a of the chuck is caused to rock around the section 23b which is held against rotation by the catch 28, the outer end 28a of which may be shifted by operators finger, until one of the cutting ridges of the drill is brought into a radial plane of the grinding wheel as illustrated in Fig. 3. A magnifying glass the position of which is adjustable makes this operation easier. The control handle 20' is then released so as to allow the drum 17 to rotate round the rod 16 and to adjust thus the angular setting of the drill. 17 carries a mark 30 cooperating with a scale 31 provided on the sleeve 13. The slider 18 is then shifted with reference to the drum 17 forming its slideway so as to define the cutting angle of the drill. Said angle may be checked through the mark 32 on the drum 17 cooperating with a scale 33 on the slider. The nut-shaped handle 20 is then tightened so as to lock both the drum 17 and the slider 18 in their adjusted positions. The system carrying the drill is then caused through a shifting of said handle 20 to rock bodily round the axis of the :pivot 12 so as to make the tip of the drill register with the edge of the grinding wheel 4. The chuck 23 is finally shifted angularly by 180 and a further operation of the handle 20 leads a second time the drill into registry with the grinding wheel for the sharpening of the second cutting surface of the drill.

It should be noticed that the different rocking movements of the drill-carrying system round the axis of the pivot 12 are limited by a pin 34 carried by the sleeve 13 (Fig. 2) and moving inside a notch 35 formed inside an arcuate grooved sector 36 forming thus a double To this end, the drum 3 abutment. Said sector is frictionally fitted over a conical terminal bearing surface 12a of the pivot 12, the amount of friction being adjusted by a nut 37. It is thus possible by urging slightly-the'handle 20 beyond its normal path to'shift the double abutment 36 and to modify thereby the range within which the drill-carrying system rocks freely.

In the modification illustrated in Fig. 4, the member 38 forming the carrier for the front end of the'drill is provided with a bearing surface 38a corresponding to the bearing surface 15a in the first embodiment illustrated in Fig. 3, while it is further provided with a small shoulder 38b forming an abutment for the edge ,of one of the helical grooves of the drill. The location of the latter is thus very accurately defined. The shoulder 38b may in fact be formed by an insert fitted in the carrier 38 so as to be vertically adjustable in accordance with the size of the drill to be ground.

What I claim is:

1. In an apparatus for sharpening drills comprising a frame and agrinding wheel revolubly carried by said frame,ythe"provision of two carriers for the corresponding ,ends of the drill, the rear drill carrier including a removable chuck adapted to carry the rear end of the drill and provided with an axial recess at its rear end, a bracket and a stud carried by said bracket and adapted to engage said opening in the chuck and the front carrier being provided with two bearing surfaces perpendicular to each other and adapted to engage the tip of the drill, a sleeve revolubly carried by the frame round an axis parallel with the axis of the grinding wheel in the'immediate vicinity of the latter and carrying radially and revolubly the front drill carrier, a rod carried radially and revolubly by the sleeve in diametrical alignment with the front drill carrier, a drum adapted to revolve round said rod and the outer surface of which forms a part' cylindrical slideway, the axis of which is directed radially with reference to the rod, aslider to which the bracket on the rear drill carrier is secured and having an inner cylindrical surface matching the cylindrical slideway of the drum to be shifted angularly thereon in accordance with the cutting angle to be obtained for the drill, said slider being provided with an arcuate slot slidingly fitted over the rod, and a nut screwed over the outer end of said rod and adapted to lock the slider and the drum with reference to the drum and to the sleeve respectively, said nut forming a handle controlling the angular movements of the drum and of the sleeve.

2. In an apparatus for sharpening drills comprising a frame and a grinding wheel revolubly carried by said frame, the provision of two carriers for the corresponding ends of the drill, the rear drill carrier including a removable chuck adapted to carry the rear end of the drill and provided with two diametrically opposed notches and with an axial recess at its rear end, a bracket and a stud carried by said bracket and adapted to engage said opening in the chuck and the front carrier being provided with two bearing surfaces perpendicular to each other and adapted to engage the tip of the drill, a sleeve revolubly carried by the frame round an axis parallel with the axis of the grinding wheel in-the immediate vicinity of the latter and carrying radially and revolubly the front drill carrier, a rod carried radially and revolubly by the sleeve in diametrical alignment with the front drill carrier, a drum adapted to revolve around said rod and the outer surface of which forms a part cylindrical slideway, the axis of which is directed radially with reference to the rod, a slider to which the bracket on the rear drill carrier is secured and having an inner cylindrical surface matching the cylindrical slideway of the drum to be shifted angularly thereon in accordance with the cutting angle to be obtained for the drill, said slider being'provided with an arcuate slot slidingly fitted over the rod, a catch pivotally secured to the slider and adapted to engage selectively said notches in the chuck to hold the latter in correspondingly opposed angular positions for the sharpening of difierent surfaces of the drill, and a nut screwed over the outer end of said rod and adapted to lock the slider and the drum with reference to the drum and to the sleeve respectively, said nut forming a handle controlling the angular movements of the drum and of the sleeve.

3. In an apparatus for sharpening drills comprising a frame and a grinding wheel revolubly carried by said frame, the provision of two carriers for the corresponding ends of the drill, the rear drill carrier including a removable chuck adapted to carry the rear end of the drill and provided with an axial recess at its rear end, a bracket, a stud carried by said bracket and adapted to engage said opening in the chuck with a sliding fit and a micrometric screw defining the axial location of the stud in the chuck and the front carrier being provided with two bearing surfaces perpendicular to each other and adapted to engage the tip of the drill, a sleeve revolubly carried by the frame round an axis parallel with the axis of the grinding wheel in the immediate vicinity of the latter and carrying radially and revolubly the front drill carrier, a rod carried radially and revolubly by the sleeve in diametrical alignment with the front drill carrier, a

, drum adapted to revolve round said rod and the outer and a nut screwed over the outer end of said rod and adapted to lock the'slider and the drum with reference to the drum and to the sleeve respectively, said nut forming a handle controlling the angular movements of the drum andof the sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 2,344,420 Schwartz Mar. 14, 194.4 2,614,370 Kapnick Oct. 21, 1952 2,663,126 Amiet Dec. 22, 1953 2,748,543 Pardee June 5, 1956 Nyholm Oct. 15, 1957