US3596414A

US3596414A - Metal-finishing apparatus

Info

Publication number: US3596414A
Application number: US877247A
Authority: US
Inventors: Antonio Pirrello
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1969-11-17
Filing date: 1969-11-17
Publication date: 1971-08-03
Anticipated expiration: 1988-08-03

Abstract

A metal-finishing assembly which has a quickly replaceable abrasive and lookthrough viewing means for continually observing the surface being finished. One form of the assembly includes a disk-shaped member having radially extending abrasive tubes resiliently mounted on arms. The assembly is attached to a shaft by locking means which may easily e disengaged to allow the tubes to be rotated on the arms.

Description

United States Patent lnventor Antonio Pirrello Lincoln Park, Mich.

Appl. No 877,247

Filed Nov. 17, 1969 Patented Aug. 3, 1971 Assignee General Motors Corporation Detroit, Mich.

METAL-FINISHING APPARATUS 6 Claims, 3 Drawing Figs.

US. Cl 51/358, 51/1701, 51/109 Int. Cl ..B24d 17/00, B24b 23/00, 13241: 9/00 Field of Search 51/358,

i 1 a i g [56] References Cited UNITED STATES PATENTS 3,452,485 7/1969 Broscoff 51/109 2,420,876 5/1947 Freud 51/90 1,654,275 12/1927 Strand... 15/230 1,498,224 6/1924 Atwood..... 125/5 241,351 5/1881 Graham 125/5 Primary ExaminerHarold D. Whitehead Attorneys-William S. Pettigrew and Robert J. Wallace ABSTRACT: A metal-finishing assembly which has a quickly replaceable abrasive and lookthrough viewing means for continually observing the surface being finished. One form of the assembly includes a disk-shaped member having radially extending abrasive tubes resiliently mounted on arms. The assembly is attached to a shaft by locking means which may easily e disengaged to allow the tubes to be rotated on the arms.

PATENTED AUG 3 Ian INVEN'I'UR ATTOFH-lh( METAL-FINISHING APPARATUS This invention relates to metal finishing, and particularly to a metal-finishing assembly adaptable for use in a portable metal-finishing tool.

During the substantially continuous metal-finishing operations such as one encounters a commercial assembly line, the abrasive of a metal-finishing surface wears off, and must be frequently replaced. Often the abrasive is in disk form adhesively attached to a backup plate or pad. Periodic replacement of this type of abrasive is often unduly time consuming and can, therefore be costly. This can be particularly true, when the metal finishing is being performed on a high volume commercial production line where only a limited time is available for metal finishing or working each successive unit.

If the abrasive is not replaced frequently, a smooth area can appear thereon. A severely worn or smooth area on an abrasive can cause high and low spots to appear in the surface of the work. If one ultimately desires a generally specular appearance in the work surface, after a final painting, such a surface must often be refinished. Refinishing such a surface adds a considerable extra cost to the overall cost of the metalfinishing operation. It is generally less costly to simply change or replace abrasive disks more frequently than to incur refinishing costs. Often when the abrasive is replaced, only a minor portion of the abrasive area is won. However, the entire disk is usually discarded. This, of course, is inefficient use of such a abrasive disk.

Furthermore, the usual prior art type of hand-held tool must be periodically removed from the surface being finished in order to inspect that surface. Repeated removal of a tool from the metal surface for inspection purposes can be time consuming. Besides, placing the tool back onto the surface, if not done properly can cause edge cutting and ditching on the surface.

Accordingly, it is a principal object of this invention to provide a metal-finishing assembly wherein a worn abrasive sur face can easily and quickly be replaced.

Another object of this invention is to provide a metal-finishing assembly wherein the entire abrasive surface can be used more efficiently.

Still another object of this invention is to provide a metalfinishing assembly wherein the surface being finished can be continually observed during the metal-finishing operation.

Other objects, features and advantages of this invention will become more apparent from the following description of the preferred example and from the drawings in which:

FIG. 1 is a plan view of a metal tool having a finishing assembly made in accordance with this invention;

FIG. 2 is a partial sectional view taken along the line 22 of FIG. 1; and

FIG. 3 is a view showing the parts of the assembly separated from each other.

Referring now primarily to FIG. I, it shows a portable machine including a disk-shaped metal-finishing assembly and a tool 10. Tool has inlet means 12 and a conventional airdriven motor having a shaft 14. Tool 10 is adaptable to be hand held generally at handles 16 and 18. The disk-shaped metal-finishing assembly includes a central hub having radially extending abrasive tubes with wedge-shaped openings 19 therebetween. The openings provide lookthrough viewing means when the assembly is rotated. The disk assembly is rigidly attached to shaft 14, and made rotatable therewith, by locking means in the form of a nut 20 recessed within the hub of the assembly.

The assembly includes, as is best shown in FIG. 3, an inner backup plate 22 and an outer abrasive holding member 25 adaptable to be recessed within plate 22. Both plate 22 and member 24 are made of aluminum. However, any durable plastic or metallic material is suitable.

Member 24 includes the outer hub segment 26 of the assembly and has a central aperture 28 for receiving shaft 14. Aperture 28 is located within a recess 30 which accommodates nut 20. A pair of registration openings afelocated on opposite sides of recess 30 on hub segment plurality of abrasive receiving arms 34 integrally formed about the periphery of hub segment 26 extend radially therefrom about 1.5 inches. Corresponding parts of each are angularly displaced from each other about 30. Hub segment 26 has. a diameter of about 3 inches. Arms 34 are of semicircularlike cross section, and have a radius of curvature of about 0.375 inch and a length of about 1.5 inches. Each arm 34 includes an outer flat surface having a width of about 0.70 inch. The flexible abrasive tubes each have a length of about 1.5 inches and a diameter of about 0.75 inch. Hence, they are loosely mounted on each arm 34. Each arm is beveled at its respective free ends to facilitate positioning the tubes thereon.

Backup plate 22 includes the inner hub segment 36 of the assembly and a peripheral rim 38 and] a plurality of web elements 40 therebetween. Plat 22 further includes a central aperture 42, for receiving shaft 14, and a pair of upstanding index plugs 44. The web elements 40 are thinner than rim 38, forming a recess 46 within plate 22 for receiving member 24. Corresponding parts of each web element 40 are similarly angularly displaced from each other about 30. Each web element has a width of about 0.5 inch and a thickness of about 0.25 inch.

Index plugs are insertable within openings 32 of member 28 to generally align each arm with a corresponding web element and to loosely seat member 24 within recess 46. Each web element 40 thus registers with an arm to form a backing for an abrasive tube. Each arm 34 terminates closely adjacent the inner periphery of rim 38. The locking nut 22 securely seats member 24 within recess 46. Thusly seated, the web elements of member 24 and the arms 34 cooperate to clamp the tubular abrasives. This forces the abrasives to generally remain contiguous to the rounded surface of the arms. The abrasive generally overlying the flat surface of each arm 34 is generally free to resiliently follow the surface contours of the work.

As can easily be understood, the wedge-shaped openings adjacent each abrasive tube provide lookthrough viewing means allowing one to continually observe the work as the assembly is rotated by shaft 14. Moreover, it should easily be understood that whenever the abrasive engaging the work becomes worn, one merely has to rotate the tubes on the arms after disengaging the recessed locking means. Accordingly, the entire abrasive area of a tube may be utilized.

It should be further understood that while certain dimensions and angles have been used in describing this preferred embodiment, the invention is not to be so limited. For example, the corresponding parts of the abrasive receiving arms as herein described have an angular displacement of 30; other angular displacement can, of course, be suitable. Likewise, one may use an appropriate grit size that is suitable for a particular application. However, it has been found that for finishing sheet metal at a speed of about 3,000 rpm, a grit size of about 30 to is preferable.

What I claim is as follows:

1. A metal-finishing apparatus which comprises a hub having a central aperture for receiving ashaft, a rim coaxial with said hub, a plurality of arms each having a free end extending radially from said hub, abrasive tubes mounted on each of said plurality of arms, backing means for each of said abrasive tubes, and said arms, aid backing means and said abrasive tubes cooperating to define a plurality of openings between said hub and said rim providing lookthrough viewing means as the disk is rotated.

2. The metal-finishing apparatus recited in claim I wherein the plurality of arms each terminate closely adjacent the rim, the backing means are a plurality of web elements each of which is closely adjacent one of the plurality of arms and generally coextensive therewith, and the abrasive tubes are resiliently mounted on each of the plurality of arms.

3. A metal -finishing apparatus which comprises a hub having an outer segment, an inner segment, and a central aperture for receiving a shaft, a rim coaxial with said hub, a plurality of arms integralwith said outer segment and of semicircularlike crosssection each having a free end and extending radially therefrom terminating closelyv adjacent said rim, abrasive tubes loosely mounted on said arms, a plurality of web elements integral with said inner segment and said rim, each of 5 said web elements generally coextensive with a corresponding arm providing a backing for each of said tubes and said arms, locking means securing the disk to the shaft and urging said web elements into clamping engagement with said tubes restraining movement on said arms, said web elements and said tubes cooperating to define a plurality of openings between said hub ands'aid rim providing a lookthrough viewing means as the disk is rotated by the shaft.

4. A metal-finishing assembly which comprises a backup plate including an inner hub segment having a central aperture, a coaxial rim and a plurality of web elements extending radially from said hub intersecting said rim forming a recess about the periphery of said rim, an abrasive holding member seated within said recess, said member having and outer hub with a central recess having an aperture and a plurality of arms extending radially from said outer hub terminating closely adjacent said rim, an abrasive tube mounted on each of said plurality of arms, and said arms, said web elements and said tubes cooperating to define a plurality of openings between said hubs and said rim providing lookthrough viewing means as the disk is rotated.

5. The metal-finishing assembly recited in claim 3 wherein the outer hub of the abrasive holding member has at least one index opening and the backup plate has at least one upstanding index plug within the index opening.

6. A metal-finishing assembly in the form of a diskadaptable to be rotated by a shaft which comprises a backup plate including an inner hub segment having a central aperture, a coaxial rim, a plurality of web element extending radially from said inner hub segment intersecting said rim forming a recess about the periphery of said rim and a pair of upstanding index plugs on opposite sides of said hu b, an abrasive holding member having an outer hub with a central recess including an aperture, and a plurality of arms'of semicircularlikc cross section having an outer flat surface and an inner rounded surface extending radially from said outer hub, and a pair of index openings on opposite sides of said central recess receiving said index plugs seating said member within said recess about the periphery of said rim generally aligning each of said plurality of arms coextensively overlying one of said plurality of web elements and closely adjacent said rim, an abrasive tube resiliently mounted on each of said arms, said web elements, said arms and said tubes defining a plurality of openings between said hubs and said rim providing lookthrough viewing means as the disk is rotated, and locking means in said central recess of said second hub securing the assembly to the shaft and urging said web elements into clamping engagement with said tubes restraining movement of said tubes on said arms.

Claims

1. A metal-finishing apparatus which comprises a hub having a central aperture for receiving a shaft, a rim coaxial with said hub, a plurality of arms each having a free end extending radially from said hub, abrasive tubes mounted on each of said plurality of arms, backing means for each of said abrasive tubes, and said arms, aid backing means and said abrasive tubes cooperating to define a plurality of openings between said hub and said rim providing lookthrough viewing means as the disk is rotated.

2. The metal-finishing apparatus recited in claim 1 wherein the plurality of arms each terminate closely adjacent the rim, the backing means are a plurality of web elements each of which is closely adjacent one of the plurality of arms and generally coextensive therewith, and the abrasive tubes are resiliently mounted on each of the plurality of arms.

3. A metal -finishing apparatus which comprises a hub having an outer segment, an inner segment, and a central aperture for receiving a shaft, a rim coaxial with said hub, a plurality of arms integral with said outer segment and of semicircularlike cross section each having a free end and extending radially therefrom terminating closely adjacent said rim, abrasive tubes loosely mounted on said arms, a plurality of web elements integral with said inner segment and said rim, each of said web elements generally coextensive with a corresponding arm providing a backing for each of said tubes and said arms, locking means securing the disk to the shaft and urging said web elements into clamping engagement with said tubes restraining movement on said arms, said web elements and said tubes cooperating to define a plurality of openings between said hub and said rim providing a lookthrough viewing means as the disk is rotated by the shaft.

6. A metal-finishing assembly in the form of a disk adaptable to be rotated by a shaft which comprises a backup plate including an inner hub segment having a central aperture, a coaxial rim, a plurality of web element extending radially from said inner hub segment intersecting said rim forming a recess about the periphery of said rim and a pair of upstanding index plugs on opposite sides of said hub, an abrasive holding member having an outer hub with a central recess including an aperture, and a plurality of arms of semicircularlike cross section having an outer flat surface and an inner rounded surface extending radially from said outer hub, and a pair of index openings on opposite sides of said central recess receiving said index plugs seating said member within said recess about the periphery of said rim generally aligning each of said plurality of arms coextensively overlying one of said plurality of web elements and closely adjacent said rim, an abrasive tuBe resiliently mounted on each of said arms, said web elements, said arms and said tubes defining a plurality of openings between said hubs and said rim providing lookthrough viewing means as the disk is rotated, and locking means in said central recess of said second hub securing the assembly to the shaft and urging said web elements into clamping engagement with said tubes restraining movement of said tubes on said arms.