US3858362A

US3858362A - Die grinder

Info

Publication number: US3858362A
Application number: US444342A
Authority: US
Inventors: Walter N Welsch
Original assignee: Dynabrade Inc
Current assignee: Dynabrade Inc
Priority date: 1973-08-27
Filing date: 1974-02-21
Publication date: 1975-01-07
Anticipated expiration: 1992-01-07

Abstract

A grinder includes a drive tube dimensioned to freely receive an elongated, grinding element having an axially extending opening; locking means for releasably locking the grinding element for rotation with the drive tube; and an adapter insert dimensioned to be slideably received within the drive tube and mounting a coaxially extending support and rigidifying mandrel dimensioned to be slideably received within the opening of the grinding element.

Description

Q I C Untte States 1 atent 11 1 1111 3,858,362 Welsch 1 Jan. 7, 1975 [54] DIE GRINDER 1,254,071 l/l918 Reinlie 51/206 R 2,359,594 10/1944 T h 1k 1 1 .51 170 PT [75] Inventor: Walter Welsch, Tonawanda 2,722,092 11/1955 51/403 [73] Assignee: Dynabrade, Inc., Tonawanda, NY. FOREIGN PATENTS OR APPLICATIONS [22] Filed: Feb. 21, 1974 112,910 4/1961 Denmark 285/348 [21] Appl Primary Examiner-James L. Jones, Jr.

Related US. Application Data Attorney, g or FirmB6an d e [63] fg7n3tinuation-in-part of Ser. No. 391,686, Aug. 27, [57] ABSTRACT A grinder includes a drive tube dimensioned to freely [52] US. Cl. 51/170 PT, 51/403 receive an elongated, grinding element having an axi- [51] Int. Cl B241) 23/00, 824d 11/00 ally extending opening; locking means for releasably [58] Field of Search 51/170 PT, 263, 71, 403, locking thegrinding element for rotation with the 51/361, 206 R, 206 NF; 285/348; 279/] Q, drive tube; and an adapter insert dimensioned to be 102, 103 slideably received within the drive tube and mounting a co-axially extending support and] rigidifying mandrel [56] References Cited dimensioned to be slideably received within the open- UNITED STATES PATENTS 111g of the gnndmg element- 828,894 8/1906 Martin 5l/l65.93 10 Claims, 3 Drawing Figures 1 REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my copending application Ser. No. 391,686, filed Aug. 27, 1973.

BACKGROUND OF THE INVENTION working end thereof to severe vibration or bending conditions. These grinding elements may be in the form of either a bonded grinding wheel or a cartridge roll formed by winding coated abrasive material about a forming mandrel.

More specifically, this grinding tool basically comprises a drive tube dimensioned to slideably receive and support a given maximum diameter grinding element, and means for releasably locking the grinding element for rotation with the drive tube. As the end of the grinding element arranged to protrude from the forward end of the drive tube becomes worn, the locking device would be released to permit an additional length of the grinding element to be withdrawn from within the drive tube.

When it was desired to employ a grinding element having a diameter smaller than the given maximum diameter, it was necessary to employ an adapter assembly including a filler or reducing sleeve dimensioned to fill the space between the drive tube and the smaller diameter grinding element in order to provide proper external support for the latter. A drawback of this construction is the requirement that the grinding tool must be provided with a separate reducing sleeve for each reduced size grinding element to be used by the tool.

SUMMARY OF THE INVENTION The present invention relates to the provision of a single removable adapter, which permits the drive tube of the grinding tool disclosed in my above mentioned co-pending application to provide proper support for variously sized smaller diameter grinding elements of the cartridge roll variety. Moreover, the improved construction has been found to offer significantly improved support for this type of grinding element.

In a modified form of the present invention the adapter may be incorporated as a permanent part of the drive tube.

DRAWINGS The nature and mode of operation of the present invention may be more fully described in the following detailed description taken with the accompanying drawings wherein:

FIG. 1 is a partially sectionalized side elevational view of a grinding tool embodying the present invention;

FIG. 2 is an exploded view of that part of the grinding tool included within the area designated as FIG. 2 in FIG. 1; and

FIG. 3 is an exploded view similar to FIG. 2, but showing a modified form of the present invention.

DETAILED DESCRIPTION The grinding tool designated as 10 in FIG. 1 is similar to that described in my co-pending application Ser. No. 391,686, filed Aug. 27, 1973 from the standpoint that it generally includes a hollow metal casing or tool housing 12; a drive assembly or mechanism 14; an elongated drive tube 16, which has a front end 16a arranged to extend outwardly through a casing front wall opening 18 and is dimensioned to accommodate an elongated, relatively uniform diameter cylindrical grinding element 20; a locking device 22 for releasably locking or clamping grinding element 20 for rotation with drive tube 16; a ball bearing or other suitable bearing device 24 for mounting drive tube 16 for rotation within casing 12; and a manually operable latch device 26, which is fitted within casing bottom wall opening 28 for selectively constraining rotation of drive tube 16 when it is desired to operate locking device 22.

While, as in my prior construction, grinding tool 10 is not limited to the utilization of my specific drive assembly, assembly 14 is shown in FIG. 1 for purposes of illustration as including a power source, such as an air motor 30, which is suitably affixed to casing rear wall 32 and drivingly connected through a casing rear wall opening 34 to a drive pulley 36 arranged within casing 12; pulley 36 being coupled to the rear end 16b of drive tube 16 by means of an endless belt 38. The tension in belt 38 may be selectively controlled by a casing rear wall mounted belt take up or idler pulley 40. Motor 30 may have any suitable shut off or speed control, such as may be afforded by a pivotally supported lever 42, which is adapted to be squeezed by the hand of an operator during use of the grinding tool. Also, the surface of drive pulley 36 and the surface of drive tube rear end 1612 would preferably be slightly crowned in order to insure proper belt tracking. The illustrated construction is preferred, since air motor 30 also serves as a convenient hand grip for manipulating tool 10. However, if desired, casing 12 may be shaped to define a convenient hand grip, such as a pistol grip.

Locking device 22 is best shown in FIG. 2 as including a clamping member 50, and a resiliently deformable ring shaped member 52. Clamping member 50, which may be characterized as being of a generally cupshaped configuration, has an internally threaded rim portion 54 by which it may be adjustably and removably mounted on drive tube front end 16a and has an opening 56 extending axially through its radially extending base wall portion 58. The construction of clamping member 50 and ring member 52 is preferably somewhat similar to that described as an alternative or simplified locking construction in my co-pending application, except that when a sufficiently soft resiliently deformable material is used in forming the ring member, the need for employing cooperating camming surfaces to effect deformation thereof into clamping engagement with the grinding element is eliminated.

Ring member 52 is preferably sized to be snugly fitted within clamping member 50 forwardly of threaded rim portion 54 and to slideably receive a given size of grinding element 20, whereby to facilitate adjustments of the grinding element lengthwise of drive tube 16 when the ring member is not compressed or deformed. Rubber having about 50 Durometer (Shoe A) may be conveniently employed to form a ring member with a useable life under normal daily use of upwards of about one month. Longer life may be achieved by employing a urethane of from between about 70-90 Durometer (Shoe A), but a ring member formed of this type of material would normally have to be cammed into clamping engagement with the grinding element.

As will be apparent, when clamping member 50 is moved towards, that is, threaded onto drive tube front end 16a, ring member 52 is clamped or axially compressed between the clamping member and drive tube front end 16a, such that the ring member is radially deformed into surface clamping engagement with grinding element 20 intermediate its ends. By this means, the grinding element is constrained for rotation with the drive tube. When clamping member 50 is unscrewed sufficiently to release ring member 52 from deforming clamping pressure, grinding element 20 may be manually pulled axially outwardly through the ring and clamping members for purposes of adjustment, i.e., replacement of the front or outwardly projecting end of the grinding element as it is worn away during use.

Again referring to FIG. 1, it will be understood that latch device 26 is employed to releasably constrain rotation of drive tube 16, during threading and unthreading movements of clamping member 50. To this end, latch device 26 includes a plunger operator 70, which may be manually depressed against the return bias of a coil spring 72 for receipt within a drive tube wall aperture 74.

As thus far described, tool is only adapted to employ a grinding element having some given maximum diameter or size permitting it to be properly slip or slide fit supported within drive tube 16. As a practical matter, the drive tube would be sized to permit a grinding element to be easily inserted, while at the same time serving to maintain the grinding element essentially centered within the drive tube during tool operation when sidewise grinding pressure is applied to the projecting end of the grinding element. The grinding element employed with tool 10 may either be in the form of a bonded grinding wheel or a cartridge roll, the latter being formed by winding or wrapping a coated abrasive material about a forming mandrel.

In my prior tool construction, adapter assemblies are provided to afiord proper external support for smaller or reduced diameter grinding elements of both types within drive tube 16. Each of these assemblies includes a filler or reducing sleeve, which is externally sized to permit it to be slide or slip fit supported within the drive tube and internally sized to permit a given smaller diameter grinding element to be slide fit supported therein. Of course, the diameter of the grinding ele ment to be used by tool 10 will determine the internal dimension of the ring member employed to clamp same for rotation with the drive tube. My prior construction has the advantage that each assembly is capable of accommodating both types of grinding elements. On the other hand, it has been found that the nature of a grinding operation or economics often dictates that a cartridge roll type of grinding element be primarily employed.

The present invention has resulted from a desire to minimize the number of assembly components necessarily provided for a grinding tool in situations where cartridgeroll type grinding elements are to be primarily employed, and the observation that commercially available cartridge rolls of various outside or external diameters are normally formed on a common size forming mandrel, thereby resulting in their having like sized axially extending through openings 20'.

Again referring to FIGS. 1 and 2, it will be understood that the present invention is directed towards the provision of a single insert 80, which may be removably inserted into drive tube 16 whenever it is desired to use any grinding element of the cartridge roll type having an external diameter smaller than that which can be properly supported directly by the drive tube. Insert includes a sleeve member 82, which is externally dimensioned to be slide or slip fitted within drive tube 16; an elongated mandrel or grinding element support 84; and any suitable means, such as a disc 86, which serves to rigidly connect the rear end portion mandrel 84 to the rear end portion of sleeve 82 such that the mandrel 84 is coupled for rotation with and extends coaxially of the sleeve member. As a practical matter, it is desirable to provide a relatively closer fit between sleeve 82 and drive tube 16 than that illustrated in FIG. 1 in order to positively position the sleeve and thus mandrel 84 in a co-axial relationship within the drive tube. Also, it is preferable to form sleeve 82 with the minimum wall thickness permitted by structural considerations in order to permit inert 80 to accommodate a full size range of reduced diameter grinding elements.

The front end'portion 82a of sleeve member 82 is enlarged to define a radially extending rear surface dimensioned to axially abut against drive tube front end 16a inwardly of its outer threaded surface and a radially extending front surface arranged to engage ring member 52. With this construction, whenever clamping member 50 is threaded onto drive tube 16, ring member 52 is resiliently deformed into frictional surface engagement with grinding element 20 and sleeve front end portion 82a is forced into frictional surface engagement with drive tube front end 16a, whereby both the grinding element and insert 80 are coupled for rotation with drive tube 16.

Mandrel 84 is sized and shaped to permit it to be easily slide fitted with grinding element opening 20, while at the same time providing proper internal support for such element. Mandrel 84 has a length sufficient to extend forwardly beyond sleeve 82 and thus drive tube 16, such that its forward end portion is at least axially co-extensive with ring member 52 when tool 10 is in its assembled condition shown in FIG. 1. Preferably, the front end portion of mandrel 84 would extend outwardly beyond member 50 through a short distance, eg. inch, in order to provide positive internal support for the grinding element immediately adjacent its point of application to a workpiece. As in the case of my prior tool construction, the internal diameter of the ring member employed will depend upon the diameter of the grinding element to be used.

In the present construction, when the outwardly projecting or front end of grinding element 20 has been worn away, clamping member 50 is unscrewed sufficiently to release ring member 52 from deforming pressure and the grinding element is then manually pulled outwardly through the ring and clamping members to expose a new length of grinding element. With the present construction, this adjustment may be repeated until the length of the grinding element remaining is insufficient to permit its being gripped by the ring member. When it is desired to employ a bonded gripping wheel in tool 10, clamping member 50 would be unscrewed from the drive tube in order to permit removal of the present adapter.

Reference is now made to FIG. 3, which illustrates a modified adapter construction for use with grinding tools, intended only to employ cartridge roll type grinding elements. In this form of the invention, sleeve member 82 is dispensed with and mounting disc 86 is employed to couple mandrel 84' directly to the rear end of the drive tube. This permits all diameters of grinding elements to be properly supported within the drive tube. Preferably disc 86 is permanently fixed to both the drive tube and insert, as for instance by welding, adhesive or the like. However, if desired, disc 86' may be removably attached, as by screw threads or other suitable coupling device to either or both of the drive tube and mandrel in order to permit bonded grinding wheels to be accommodated within the drive tube.

It is anticipated that bonded grinding wheels may in the future be mold formed to provide an axially disposed opening extending either wholly or partially therethrough. Thus, the claims of the present invention are not to be limited solely to wound cartridge rolls.

1 claim:

1. In a grinding tool adapted for use with a grinding element having an end adapted to be progressively worn away by engagement with a workpiece during operation of said grinding tool, said grinding element being characterized as having an elongated generally cylindrical configuration with a co-axially extending opening, the combination comprising:

a rotatably supported drive tube, said drive tube being dimensioned to freely accommodate said grinding element therewithin to removably extend through a front end thereof;

a mandrel supported to extend co-axially within said drive tube and having a front end portion disposed forwardly of said front end, said mandrel conforming to said grinding element opening, whereby to permit said grinding element to be slideably supported on said mandrel within said drive tube;

means for rotating said drive tube; and

locking means carried by said front end for releasably clamping said grinding element intermediate opposite ends thereof for rotation with said drive tube, whereby said end of said grinding element normally projects forwardly of said front end beyond said locking means and beyond said front end portion during operation of said tool.

2. In a grinding tool according to claim 1, wherein said locking means includes resiliently deformable means for releasably clamping said grinding element for rotation with said drive tube and clamping means for resiliently deforming said resiliently deformable means.

3. In a grinding tool according to claim 2, wherein saie deformable means is a ring member having a through opening dimensioned to slideably receive said grinding element, and said clamping means is a generally cup-shaped clamping member internally dimensioned to removably receive said ring member and having an opening through a base portion thereof sized to freely receive said grinding element, said clamping member being adjustably threaded onto said drive tube front end for releasably clamping said ring member axially intermediate said clamping member and said drive tube, whereupon said ring member is resiliently deformed radially into clamping engagement with said grinding element.

4. In a grinding tool according to claim 1, wherein said mandrel is removably supported within said drive tube by means including a sleeve exteriorly dimensioned to be slide fitted within said drive tube and interiorly dimensioned to freely receive said grinding element, said sleeve having a front end portion defining a radial surface dimensioned to abut against said front end of said drive tube inwardly of an outer surface thereof, and mounting means for fixedly supporting a rear end portion of said mandrel on a rear end portion of said sleeve, whereby said mandrel extends co-axially of said sleeve and has said front end portion thereof arranged forwardly of said front end portion of said sleeve; and said locking means includes a generally cup-shaped clamping member and a ring member formed of a resiliently deformable material, said ring member having a through opening dimensioned to slideably receive said grinding element, said clamping member being internally dimensioned to removably receive said ring member and said front end portion of said sleeve and having an opening through a base portion thereof sized to freely receive said grinding element, said clamping member having a rim portion adjustably threaded onto said front end of said drive tube whereby to cooperate therewith to axially clamp said ring member against said front end portion of said sleeve and said front end portion of said sleeve against said front end of said drive tube, whereupon said ring member is resiliently deformed into clamping surface engagement with said grinding element.

5. In a grinding tool according to claim 1, wherein a rear end portion of said mandrel is permanently secured to a rear end of said drive tube 6. In a grinding tool adapted for use with generally cylindrical grinding elements having ends adapted to be progressively worn away by engagement with a workpiece during operation of said grinding tool, at least certain of said grinding elements being characterized as having given size openings extending axially therethrough, which comprises in combination:

a hollow casing having an opening through a wall thereof;

an elongated drive tube, said drive tube being dimensioned to removably accommodate said grinding elements therewithin one at a time to extend through a front end thereof;

means for supporting said drive tube for rotation within said casing with said front end of said drive tube projecting outwardly through said casing wall opening;

means for rotating said drive tube;

locking means carried by said front end of said drive tube for releasably clamping said grinding element intermediate opposite ends thereof for rotation with said drive tube wherein said grinding element normally projects forwardly of said front end beyond said locking means during operation of said tool; and

adapter means for positionally supporting said certain grinding elements within said drive tube, said adapter means including an elongated mandrel sized to permit slide fitting thereof within said given size openings and means: for mounting said mandrel to extend co-axially of said drive tube from adjacent a rear end thereof with a front end portion of said mandrel projecting forwardly beyond said front end of said drive tube.

7. A grinding tool according to claim 6, wherein said locking means includes a cup-shaped clamping member and deformable member formed of a resiliently deformable material, said clamping member being internally dimensioned to removably receive said deformable member and having an opening through a base portion thereof for freely receiving said grinding elements, said clamping member being removably fixed to said front end of said drive tube for resiliently deforming said deformable member into clamping surface engagement with said grinding element whereby to releasably clamp said grinding element for rotation with said drive tube.

8. A grinding tool according to claim 7, wherein said means for mounting said mandrel rigidly affixes a rear end portion of said mandrel to said rear end of said drive tube, and said front end portion of said mandrel projects forwardly of said drive tube at least sufficiently to be axially coextensive with said deformable member.

9. A grinding tool according to claim 7, wherein said means for mounting said mandrel includes a sleeve slideably insertable within said drive tube and means rigidly connecting a rear end portion of said mandrel to a rear end portion of said sleeve, said sleeve having a front end portion defining a radial surface engageable with a radial surface of said front end of said drive tube inwardly of an outer surface thereof, said deformable member being arranged axially intermediate said base portion of said clamping member and said front end portion of said sleeve, and said front end portion of said mandrel projects forwardly of said drive tube at least sufficiently to be axially coextensive with said deformable member.

10. An adapter for use with a grinding tool of the type employing elongated, generally cylindrical grinding elements, said tool including a rotatably supported drive tube internally dimensioned to removably slide fit support a given maximum diameter grinding element to project through a front end thereof, means for rotating said drive tube, and locking means carried by said front end for releasably clamping said grinding elements intermediate opposite ends thereof for rotation with said drive tube, whereby when an end of any of said grinding elements projecting from said front end of said drive tube and beyond said locking means becomes worn said locking means may be released to allow an additional length of such grinding elements to be withdrawn from within said drive tube, said adapter accommodating said drive tube to provide support for certain of said grinding elements having diameters smaller than said given maximum diameter and which are additionally characterized as having a common sized axially extending opening, said adapter comprising:

a sleeve dimensioned to be removably slide fit supported concentrically within said drive tube and having means for coupling same for rotation with said drive tube;

an elongated mandrel; and

means to fix a rear end portion of said mandrel to a rear end portion of said sleeve whereby said mandrel is disposed to freely extend co-axially within said sleeve for rotation therewith, said mandrel having a front end portion projecting forwardly beyond a front end of said sleeve and said mandrel being sized to be slide fitted within said common sized opening whereby to afford interior support for said certain smaller diameter grinding elements.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3858362 Dated January 7, 1975 Walter N. Welsch Iuventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 21, "my" should read any Column 4, line 24, "inert" should read 1- insert Column 4, line 65, "gripping" should read grinding Column 5, line 57, "saie" should read said Signed and sealed this 2 3th day of June U375.

C. ZEARS IALL DANE? R Til C. MASON Commissioner of Patents attesting, Qfficer and Trademarks ORM Po-1oso (10-69) USCiOMM-DC eoa'le-pes U.S. GOVERNMENT PRINYING OFFICE: 869- 93 o

Claims

1. In a grinding tool adapted for use with a grinding element having an end adapted to be progressively worn away by engagement with a workpiece during operation of said grinding tool, said grinding element being characterized as having an elongated generally cylindrical configuration with a co-axIally extending opening, the combination comprising: a rotatably supported drive tube, said drive tube being dimensioned to freely accommodate said grinding element therewithin to removably extend through a front end thereof; a mandrel supported to extend co-axially within said drive tube and having a front end portion disposed forwardly of said front end, said mandrel conforming to said grinding element opening, whereby to permit said grinding element to be slideably supported on said mandrel within said drive tube; means for rotating said drive tube; and locking means carried by said front end for releasably clamping said grinding element intermediate opposite ends thereof for rotation with said drive tube, whereby said end of said grinding element normally projects forwardly of said front end beyond said locking means and beyond said front end portion during operation of said tool.

5. In a grinding tool according to claim 1, wherein a rear end portion of said mandrel is permanently secured to a rear end of said drive tube.

6. In a grinding tool adapted for use with generally cylindrical grinding elements having ends adapted to be progressively worn away by engagement with a workpiece during operation of said grinding tool, at least certain of said grinding elements being characterized as having given size openings extending axially therethrough, which comprises in combination: a hollow casing having an opening through a wall thereof; an elongaTed drive tube, said drive tube being dimensioned to removably accommodate said grinding elements therewithin one at a time to extend through a front end thereof; means for supporting said drive tube for rotation within said casing with said front end of said drive tube projecting outwardly through said casing wall opening; means for rotating said drive tube; locking means carried by said front end of said drive tube for releasably clamping said grinding element intermediate opposite ends thereof for rotation with said drive tube wherein said grinding element normally projects forwardly of said front end beyond said locking means during operation of said tool; and adapter means for positionally supporting said certain grinding elements within said drive tube, said adapter means including an elongated mandrel sized to permit slide fitting thereof within said given size openings and means for mounting said mandrel to extend co-axially of said drive tube from adjacent a rear end thereof with a front end portion of said mandrel projecting forwardly beyond said front end of said drive tube.

10. An adapter for use with a grinding tool of the type employing elongated, generally cylindrical grinding elements, said tool including a rotatably supported drive tube internally dimensioned to removably slide fit support a given maximum diameter grinding element to project through a front end thereof, means for rotating said drive tube, and locking means carried by said front end for releasably clamping said grinding elements intermediate opposite ends thereof for rotation with said drive tube, whereby when an end of any of said grinding elements projecting from said front end of said drive tube and beyond said locking means becomes worn said locking means may be released to allow an additional length of such grinding elements to be withdrawn from within said drive tube, said adapter accommodating said drive tube to provide support for certain of said grinding elements having diameters smaller than said given maximum diameter and which are additionally characterized as having a common sized axially extending opening, said adapter comprising: a sleeve dimensioned to be removably slide fit supported concentrically within said drive tube and having means for coupling same for rotation with saiD drive tube; an elongated mandrel; and means to fix a rear end portion of said mandrel to a rear end portion of said sleeve whereby said mandrel is disposed to freely extend co-axially within said sleeve for rotation therewith, said mandrel having a front end portion projecting forwardly beyond a front end of said sleeve and said mandrel being sized to be slide fitted within said common sized opening whereby to afford interior support for said certain smaller diameter grinding elements.