US3803771A

US3803771A - Device for grinding a screwdriver tip

Info

Publication number: US3803771A
Application number: US00291268A
Authority: US
Inventors: C Bunn
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-22
Filing date: 1972-09-22
Publication date: 1974-04-16
Anticipated expiration: 1991-04-16

Abstract

A grinding device for grinding of a tool such as a screwdriver and including an abrasive wheel, a guide mounted jointly with the wheel for guiding a tool into contact with the wheel, and a common mount for the wheel and the guide arranged such that the wheel can rotate relative to the guide.

Description

United States Paten Bunn Apr. 16, 1974 [54] DEVICE FOR GRINDING A SCREWDRIVER 483,042 9/1892 Brown 51/283 R TIP 1,659,687 2/1928 Hart 51/210 x 719,880 51/210 Clarence L. Bunn, 1359 SW. 21st Ten, Fort Lauderdale, Fla. 33315 Filed: Sept. 22, 1972 Appl. No.: 291,268

Inventor:

US. Cl. 51/170 T, 51/128, 51/210, B24d/7/17 Int. Cl B24b 23/02 Field of Search 51/210, 170 T, 205 WG, 51/208, 216 H, 238 R, 241 G, 128, 102; 76/88, 89

, 8 References Cited UNITED STATES PATENTS 7/1957 Petra .L 5l/l02 2/1903 Rose Primary Examiner-Harold D. Whitehead Assistant Examiner-Nicholas P. Godici Attorney, Agent, or Firm-Ultman and Flynn [5 7] ABSTRACT A grinding device for grinding of a tool such as a screwdriver and including an abrasive wheel, a guide mounted jointly with the wheel for guiding a tool into contact with the wheel, and a common mount for the wheel and the guide arranged such that the wheel can rotate relative to the guide.-

6 Claims, 6 Drawing Figures l DEVICE FOR GRINDING A SCREWDRIVER TIP BACKGROUND OF THE INVENTION One of the common functions of a grinding wheel is to grind a tool, for example, to sharpen a point, flatten a surface, raise an edge, or for similar purposes. Often the tool is simply held manually against the grinding wheel. However, manual holding of the too] often results in inaccurate grinding of the tool. It has been proposed to mount such a tool in a fixture while grinding it. However, different tools might require different fixtures. Also, the fixture may not be capable of positioning a given tool in different attitudes relative to the grinding wheel so as to grind different surfaces on a particular tool. The present invention is directed to the solution of these problems as well as other problems which will become apparent herein.

SUMMARY OF THE INVENTION The present invention is a grinding device in which a guide is jointly or commonly mounted with a grinding wheel and serves to guide a tool into contact with'the grinding wheel in the proper attitude forgrinding of a surface of the tool. The common mount for the grinding wheel and the guide allows the guide to remain stationary while the abrasive wheel rotates. In a preferred embodiment, the guide has a plurality of recesses with different orientations for accepting different tools and for positioning such tools in different attitudes for grinding of different surfaces on the tool. Thus, the

. grinding device of the invention overcomes problems Another object of the invention is to provide a grinding device capable of grinding different surfaces of a given tool.

A further object of the invention is to provide a guide for a grinding device which is capable of retaining a tool in different attitudes relative to a grinding wheel for grinding different surfaces of the tool.

A further object of the invention is to provide a simple mounting means for common mounting of a grinding wheel and a guide such that the wheel can rotate relative to the-guide.

Still another, andno less important, object of the invention is to bias the guide relative to the grinding wheel so as to absorb shocks.

Other objects of this invention will appear from the 'following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a grinding device in accordance with'one embodiment of the invention;

FIG. 2 is a horizontal sectional view of the grinding device taken along line 2-2 of FIG. 1 and looking in the direction of the arrows;

FlG. 3 is a perspective view of a guide and mounting means of the grinding device, the grinding wheel being shown in dashed lines;

FIG. 4 is an elevational view of a grinding device, partly in section, showing how certain tools are ground;

FIG. 5 is another elevational view, partly cut away, further illustrating the grinding of a tool; and

FIG. 6 is a view similar to FIG. 5 but in plan and partly cut away.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

DETAILED DESCRIPTION Referring to the drawings, the grinding device 10 includes an abrasive wheel 12, and a guide 14 both mounted on a common mount 16 which includes a shaft 18 and a mounting stud 20 extending the shaft. The common mount 16 allows the abrasive wheel 12 to rotate while the guide 14 remains stationary.

The guide 14 may take several forms, and in this embodiment, it is in the form of a disc 22 having a hollow hub 24 projecting axially from one side of the disc. The other side of the disc faces toward the abrasive wheel 12'. Abrasive wheel 12 and disc 22 have substantially the same diameter.

The shaft 18 of the mount 16 extends through the abrasive wheel 12 and projects axially outward from the side of the wheel 12 opposite the guide 14. Shaft 18 has a reduced tip 26 which is adapted to be inserted into a chuck 28 of a rotary drive means for rotating the shaft 18 and also the abrasive wheel 12. Shaft 18 has a tight fit in abrasive wheel 12 so that the wheel can be rotated by driving the shaft 18. The chuck 28 might be the chuck of a lathe, a drill, or other suitable rotary drive means.

The mount 16 also includes the mounting stud 20. Mounting stud 20 may be in the form of a bolt having threads screwed into matching threads 30 formed in a bore 32 inside the shaft 18. Since the stud 20 is screwed into the shaft 18, it is affixed both with respect to the shaft 18 and the wheel 12. As viewed in FIG. 2, the mounting stud 20 extends to the right from wheel 12 into the guide 14 and terminates at a head 34 inside a bore 36 formed in the hub 24. The mounting stud 20 has a loose fit with respect to the guide 14 so that wheel 12 and stud 20 can rotate while allowing the guide 14 to remain stationary.

Optionally, the mounting means may also include a sleeve 38 which fits loosely both with respect to the mounting'stud 20 and the guide 14. Part of the sleeve is located inside a coil spring 40. The coil spring 40 has one end butting against the head 34 of the mounting stud 20 and the other end butting against a shoulder 42 formed at the base of the bore 36. The guide 14 can slide axially along a sleeve 38 toward the head 34 in order to absorb shocks produced when grinding a tool, and the spring 40 absorbs the shocks and biases the guide 14 toward the wheel'l2. The stud 20 may carry

washers

44 and 46 at the opposite major faces of the abrasive wheel 12. The washer 46 keeps the guide 14 properly spaced from the abrasive wheel 12.

It may be noted that there will be some friction between the head 34 and the coil spring 40. There also may be some slight friction between the coil spring 40 and the shoulder 42 in the event that the coil spring moves. It is within the scope of the invention to include bearings at these points of friction if desired, but since the bearings are wholly optional, they have not been illustrated.

The guide 14 includes several recesses designated respectively as 50, 52, 54, 56, 58, 60, 62 and 64. Recess 50 is a radial slot extending through the disc portion 22 of the guide 14. In use, the slot recess 50 serves to receive the tip of a screwdriver 66 in the manner illustrated in FIG. 2. The slot 50 is parallel to the axis of wheel 12 so that the distal edge 68 of the screwdriver can be placed against the inner face 70 of the abrasive wheel 12 for grinding the edge 68 flat.

Still another recess 65 is formed in the face 72 of the guide 14 which is directly opposed to face 70 of wheel 12. The recess 65 is spaced outwardly from the axis of the disc portion 22 as shown particularly in FIG. 3, and it tapers from a point next to

recesses

62, 60 and 58 until it widens out at the periphery of the disc 22 as shown in FIG. 3. Referring to FIG. 4, it may be seen that the tip of the screwdriver 66 may be inserted into the recess 65 at an angle so that the blade of the screwdriver may be ground smooth.

Recesses

52, 54 and 56 extend through the disc portion 22 of guide 14 at an angle relative to the axis of the disc portion. Each of these recesses is an aperture, and the apertures have different diameters so as to receive tools of different sizes. These apertures are intended for receiving a Phillips head screwdriver at an angle as shown in FIG. 6, the screwdriver being designated 74. In FIG. 6, the screwdriver 74 has been inserted into aperture 52 at an angle so as to bring a ridge 76 into contact with the grinding wheel 12 so that the ridge can be ground as desired.

Recess 64 also is intended to receive the tip of the Phillips head screwdriver 74 in the manner shown in FIG. 5. In this case, the tip of the screwdriver 74 is placed in the recess 64 such that the groove between any two of the ridges 76 contacts the corner 78 of the grinding wheel 12. Thus, the corner 78 grinds the recess at the tip of the Phillips head screwdriver 74 in the desired manner.

The

recesses

58, 60 and 62 are also intended to receive the tip of a Phillips head screwdriver, and these recesses are in the form of apertures extending parallel to the axis of the grinding wheel 12 and also the disc 22. The

apertures

58, 60 and 62 have different diameters for receiving screwdrivers of different sizes. Screwdriver 74 is shown inserted in aperture 60 in FIG. 4 so that the point at the end of the screwdriver may be ground flat against the face 70 of the grinding wheel 12.

Thus, the invention provides a grinding device in which an abrasive wheel and a guide have a common mounting which allows the abrasive wheel to rotate relative to the guide. The guide retains a tool at a proper attitude relative to the abrasive wheel so that a selected surface of the tool can be properly ground. In the preferred embodiment, the guide has different recesses of different sizes at different orientations so that a tool can be retained in different attitudes.

Having thus described my invention, 1 claim:

1. A grinding device for grinding ofa screwdriver tip comprising:

an abrasive wheel,

shaft means mounting said wheel for rotation,

said shaft means having a portion projecting from one side of said wheel adapted to be coupled to a drive means,

guide means mounted at the opposite side of said wheel for guiding a screwdriver,

mounting means affixed to said wheel for mounting said guide means and allowing said guide means to float while said wheel rotates,

said mounting means including a stud projecting into said guide means but having a clearance with respect thereto for rotation of said stud in said guide means,

sleeve means for allowing axial sliding movement of said guide means relative to said stud, with said sleeve means receiving said stud inside the same and said guide means outside the same and having sliding clearance with respect thereto, and

spring means acting between said stud and said guide means for biasing said guide means toward said wheel, and

means forming at least one recess in said guide means for receiving a screwdriver tip so that the tip can contact said wheel to be ground thereby.

2. The device as claimed in claim 1 in which said recess faces said wheel.

3. The device as claimed in claim 1 in which said recess comprises an aperture extending through said guide means.

4. The device as claimed in claim 3 in which said aperture slants relative to the rotational axis of said wheel.

5. The device as claimed in claim 3 in which said aperture extends parallel to the rotational axis of said wheel.

6. In a grinding device which includes a guide having a recess for receiving a tool and an abrasive wheel to be driven by a drive means for grinding a portion of the tool, the combination with said guide and said wheel comprising;

shaft means for mounting said wheel for rotation and having a portion affixed to said wheel and a portion projecting from one side of said wheel adapted to be coupled to a drive means,

a stud affixed to said wheel and projecting from the opposite side of said wheel centrally into said guide,

sleeve means for allowing said guide to float and to reciprocate axially relative to said wheel,

said sleeve means receiving said stud inside the same and said guide outside the same and having a sliding fit with respect to said stud and said guide, and

spring means acting between said stud and said guide for biasing said guide toward said wheel.

Claims

1. A grinding device for grinding of a screwdriver tip comprising: an abrasive wheel, shaft means mounting said wheel for rotation, said shaft means having a portion projecting from one side of said wheel adapted to be coupled to a drive means, guide means mounted at the opposite side of said wheel for guiding a screwdriver, mounting means affixed to said wheel for mounting said guide means and allowing said guide means to float while said wheel rotates, said mounting means including a stud projecting into said guide means but having a clearance with respect thereto for rotation of said stud in said guide means, sleeve means for allowing axial sliding movement of said guide means relative to said stud, with said sleeve means receiving said stud inside the same and said guide means outside the same and having sliding clearance with respect thereto, and spring means acting between said stud and said guide means for biasing said guide means toward said wheel, and means forming at least one recess in said guide means for receiving a screwdriver tip so that the tip can contact said wheel to be ground thereby.

2. The device as claimed in claim 1 in which said recess faCes said wheel.

6. In a grinding device which includes a guide having a recess for receiving a tool and an abrasive wheel to be driven by a drive means for grinding a portion of the tool, the combination with said guide and said wheel comprising; shaft means for mounting said wheel for rotation and having a portion affixed to said wheel and a portion projecting from one side of said wheel adapted to be coupled to a drive means, a stud affixed to said wheel and projecting from the opposite side of said wheel centrally into said guide, sleeve means for allowing said guide to float and to reciprocate axially relative to said wheel, said sleeve means receiving said stud inside the same and said guide outside the same and having a sliding fit with respect to said stud and said guide, and spring means acting between said stud and said guide for biasing said guide toward said wheel.