US2851777A - Tool for grinding, polishing, boring and milling for dental and medical purposes - Google Patents

Description

TOOL FOR GRINDING, POLISHING. BORING AND MILLING FOR DENTAL AND MEDICAL PURPOSES Filed Nov. 15, 1954 p ,1958 E. HOFFMEISTER 2,851,777

INVE/ViO/P I. .H'ofiaz e atcr United States TOOL FOR GRINDING, POLISHING, BORING AND lgggllgNG FOR DENTAL AND MEDICAL PUR- This invention relates to an instrument for grinding, polishing, drilling and milling, more particularly for dental and medical purposes, comprising a hand piece with a rotatable driving shaft therein, and a tool unit comprising a tool arbor rotatable in a long guiding hearing which is inserted in a tubular extension of a front bearing for said driving shaft provided within the hand piece, the said tool arbor having a tool thereon in proximity to the forward end of the long guiding bearing and a drive element in proximity to the rear end of the long guiding bearing for co-operation with a drive element on the forward end of the driving shaft. For the purpose of securing the tool unit in position on the hand piece, the said tubular extension is provided with a radial aperture within which a ball is radially displaceable to enable it to enter a groove located in the long guiding bearing to receive the ball, a locking device being provided for forcing the ball inwardly to engage the groove in the long bearing member of the tool unit and to maintain it in engagement with the groove.

The present invention has for its object to provide an improved locking device which can be operated by means of an actuating member located on the outside of the hand piece in the neighbourhood of the part which is normally gripped during the use of the instrument and which is thereby in a position where it can be conveniently operated and is not in the way when operating the instrument.

The accompanying drawings show one constructional form of the invention by way of example.

In these drawings:

Figure 1 represents a hand piece with the tool inserted in longitudinal section, the ball being in the locking position;

Figure 2 represents the tool unit having a long guiding bearing with an annular groove, also in longitudinal section; a

Figure 3 shows the front bearing for the driving shaft with the extension thereof which serves to receive the tool unit, also in longitudinal section;

Figure 4 shows the bearing according to Figure 3 in plan.

Referring to Figs. 1 and 2, the tool arbor 1 is rotatable in a long guiding bearing 2 and is combined therewith to form a tool unit which can be inserted into the front end of a hand piece 3 provided with a driving shaft 8. The tool arbor 1 is held in position in the bearing 2 by means of a collar 32 at its front end and by means of a collar 33 at its rear end, a tool 31 being provided on the arbor 1 in proximity to the forward end of the bearing 2. The tool arbor 1 has a drive element thereon in proximity to the rear end of the bearing 2, the said driving element being in the form of a slotted extension 34 of the collar 33 and co-operating with a drive element 35 on the forward end of the driving shaft 8.

A forward bearing 7 for the driving shaft 8, also shown separately in Fig. 3, is arranged within the hand piece 3 which comprises a removable point 18 having an axial 2,851,777 Patented Sept. 16, 1958 ice opening therein to receive the front end of an integral tubular extension 9 of the bearing 7, the wall of the said axial opening having a screw-thread therein and the tubular extension 9 has a screw-threaded portion 21 to fit said screw-thread. After removal of the point 18 from the hand-piece, the bearing 7 with its extension can be screwed into the point 18 from the inside. For screwing the bearing '7 into position, the extension 9 is provided with a collar 19 having radial slots 16 therein for engagement by driving members provided on a tubular spanner.

The tubular extension 9 of the bearing 7 receives the long guiding bearing 2 of the tool unit and has a radial aperture 17 therein within which a locking ball 5 is located, the said aperture tapering towards the inside of the tubular extension to prevent the ball 5 from falling out when the bearing 2 of the tool unit is removed. The guiding bearing 2 of the tool unit is provided with a circumferential groove 4 which is adapted to register with the radial aperture 17 when the bearing 2 is inserted in the tubular extension 9.

The bearing 7 and its tubular extension 9 is surrounded by a sleeve 6, the inner wall of which has a conically divergent forward end 61 for co-operation with the ball 5. The sleeve 6 is displaceable axially on the bearing 7 and its extension 9 from a position in which the ball 5 can enter the wider portion of the said conically divergent end of the inner wall of the sleeve 6 and leave the groove 4 in the bearing 2, into a position in which the narrower portion of the inner wall of the sleeve bears against the ball, forcing it into the groove 4. The sleeve 6 extends rearwardly lengthwise of the hand piece and is slidable on a tubular guide member 10 surrounding the driving shaft 8 and extending into the sleeve 6. The rear end of the guide member ltl fits over a rear bearing 13 of the shaft 8 and is provided with an integral flange 11 which abuts against a retaining member 12 for the bearing 13, which is formed as a rocker bearing.

The sleeve 6 is urged into its locking position by means of a helical spring 14 which encircles the guide member 10, the said flange 11 forming the rear abutment of said spring, while the other end of the spring bears against a flange 2t) integral with the rear end of the sleeve 6. By means of the spring 14 the sleeve 6 is moved forwardly, the conically divergent end 61 of the inner wall of the sleeve sliding over the ball 5 and forcing the ball inwardly to engage the groove 4 in the bearing 2, thereby securing the tool unit in position.

In order to enable the tool unit to be exchanged, it is necessary to displace the sleeve 6 rearwardly, and for this purpose the sleeve is provided with a shoulder 24 in proximity to its rear end and adjoining the flange 20. The shoulder 24 is engaged by a stud 25 integral with a slide member 15 which is displaceable lengthwise on the outside of the part 26 of the hand piece enclosing the rear end of the sleeve 6, and which is normally gripped by the hand during the use of the instrument, the stud 25 extending through an axial slot 27 in the part 26 of the hand piece. In the operative position of the sleeve 6 shown in Fig. l, the stud 25 is located in the forward end of the slot 27 but by displacing the member 15 rearwardly by finger pressure the stud 25 is moved towards the rear end of the slot 27 and retracts the sleeve 6 against the force of the spring 14, allowing the ball 5 to leave the groove 4 in the bearing 2 and thereby freeing the tool unit to enable it to be removed.

I claim:

1. An instrument for grinding, polishing, drilling and milling, more particularly for dental and medical purposes, comprising in combination, a hand piece having a 0 rotatable driving shaft therein, a drive element on the forward end of said shaft, a forward bearing for said driving shaft within the hand piece with an integral tubular extension having a radial aperture therein, a tool unit comprising a long guiding bearing fitted into said tubular extension, a tool arbor rotatable in said guiding bearing and having a tool thereon and a drive element engaging the drive element on the driving shaft, located in proximity to the forward and rear ends of the guiding bearing, respectively, said guiding bearing having a groove therein to register with the aperture in the tubular extension, a ball in said aperture, a sleeve surrounding said tubular extension, the inner wall thereof having a conically divergent forward end for co-operation with said ball, and means including an actuating member on the outside of the hand piece for axially displacing the sleeve from a position in which the ball can enter the wider portion of the conically divergent end of the inner wall of the sleeve and leave the groove in the long bearing member of the tool unit, into a position in which the narrower portion of the inner wall of the sleeve bears against the ball to force it into the said groove and secure the tool unit in position.

2. An instrument for griding, polishing, drilling and milling, more particularly for dental and medical purposes, comprising in combination, a hand piece having a rotatable driving shaft therein, a drive element on the forward end of said shaft, a forward bearing and a rear bearing for said driving shaft within the hand piece, said forward bearing having an integral tubular extension with a radial aperture therein, a tool unit comprising a long guiding bearing fitted into said tubular extension, a tool arbor rotatable in said guiding bearing and having a tool thereon and a drive element engaging the drive element on the driving shaft, located in proximity to the forward and rear ends of the guiding bearing, respectively, said guiding bearing having a groove therein to register with the aperture in the tubular extension, a ball in said aperture, a tubular guide member within the hand piece surrounding the driving shaft in proximity to said rear bearing thereof, a sleeve slidable at its front end on said tubular extension and at its rear end on said tubular guide member, the inner wall of said sleeve having a conically divergent forward end for co-operation with said ball, and means including an actuating member on the outside of the hand piece for axially displacing the sleeve from a position in which the ball can enter the wider portion of the conically divergent end of the inner Wall of the sleeve and leave the groove in the long bearing member of the tool unit, into a position in which the narrower portion of the inner wall of the sleeve bears against the ball to force it into the said groove and secure the tool unit in position.

3. An instrument for griding, polishing, drilling and milling, more particularly for dental and medical purposes, comprising in combination, a hand piece having a rotatable driving shaft therein, a drive element on the forward end of said shaft, a forward bearing for said driving shaft within the hand piece with an integral tubular forward extension having a radial aperture therein, a tool unit comprising a long guiding bearing fitted into said tubular extension a tool arbor rotatable in said guiding bearing and having a tool thereon and a drive element engaging the drive element on the driving shaft, located in proximity to the forward and rear ends of the guiding bearing, respectively, said guiding bearing having a groove therein to register with the said aperture in the tubular extension, a ball in said aperture, a sleeve surrounding said forward bearing, tubular extension and driving shaft, the inner wall of said sleeve having a conically divergent forward end for co-operation with said ball, a spring arranged within the hand piece and bearing against the rear end of said sleeve to urge the sleeve forwardly to force said ball into the narrower portion of the inner wall of the sleeve and into said groove in the long guiding bearing of the tool unit to secure the tool unit in position, and means including an actuating member on the outside of the hand piece for axially displacing the sleeve against the force of said spring into a position in which said ball can enter the wider portion of said conically divergent end and leave the groove in the long guiding bearing of the tool unit to release the tool unit.

4. An instrument as claimed in claim 3, having a rear bearing for the driving shaft with a retaining member therefor Within the hand piece, a tubular guide member Within the hand piece surrounding the driving shaft and extending into said sleeve for slidably supporting the rear end thereof, and a rear abutment for said spring comprising a. flange integral with the rear end of said tubular guide member and abutting against said retaining member for the rear bearing of the driving shaft.

5. An instrument for grinding, polishing, drilling and milling, more particularly for dental and medical purposes, comprising in combination, a hand piece having a rotatable driving shaft therein, a drive element on the forward end of said shaft, a forward bearing for said driving shaft within the hand piece with an integral tubular forward extension having a radial aperture therein, a tool unit comprising a long guiding bearing fitted into said tubular extension, a tool arbor rotatable in said guiding bearing and having a tool thereon and a drive element engaging the drive element on the driving shaft, located in proximity to the forward and rear ends of the guiding bearing, respectively, said guiding bearing having a groove therein to register with the said aperture in the tubular extension, a ball in said aperture, a sleeve surrounding said forward bearing, tubular extension and driving shaft and having a shoulder thereon in proximity to its rear end, the inner wall of said sleeve having a conically divergent forward end for co-operation with said ball, a helical spring within the hand piece encircling said driving shaft and bearing against the rear end of said sleeve to urge the sleeve forwardly and force the said ball into the narrower portion of the inner wall of the sleeve and into said groove in the long guiding bearing of the tool unit to secure the tool unit in position, the hand piece having an axial slot therein in the part thereof which encloses the rear end of the sleeve, and a slide member displaceable lengthwise on the outside of said part of the hand piece and having a stud thereon extending through said slot and engaging said shoulder to displace the sleeve against the force of said spring into a position in which said ball can enter the wider portion of said conically divergent end and leave the groove in the long guiding bearing of the tool unit to release the tool unit.

6. In instrument as claimed in claim 3, in which the hand piece comprises a removable point having an axial opening therein to receive the front end of said tubular extension of the forward bearing of said driving shaft, the wall of said axial opening having a screw thread therein and said tubular extension having a screw threaded portion engaging said screw thread so as to enable the bearing and tubular extension to be screwed into the point from the inside, said extension having an integral collar with radial slots therein for engagement by a spanner for screwing the bearing into position.

Homann Mar. 31, 1903 Bergstrom July 23, 1935

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