US2429647A

US2429647A - Abrasive implement

Info

Publication number: US2429647A
Application number: US529973A
Authority: US
Inventors: Chalmers H Randolph
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1944-04-07
Filing date: 1944-04-07
Publication date: 1947-10-28
Anticipated expiration: 1964-10-28

Description

Oct. 28, 1947. C, H, RANDOLPH ABRASIVE IMPLEMENT Filed April 7, 1944 Patented Oct. 28, 1947 2,429,647 ABRAsIvE IMPLEMENT Chalmers H. Randolph, St. Paul, Minn., assignor to Minnesota. Mining & Manufacturing Company., St. Paul, Minn., a corporation of Dela- Ware Application April 7, 1944, Serial No. 529,973

12 Claims. l

This invention relates to implements for employing sheeted abrasive material in abrading operations.

It finds particular utility in the form of implements suitable for using abrasive tape (which may be strips of the abrasive sheet material that is commonly calledv sandpaper) in abrading irregular and/or small surfaces, or for various special abrading operations.

One objective is to provide an implement which will abrade efficiently with abrasive tape and which will itself hold a substantial supply of the tape in a manner to permit bringing fresh portions of tape into abradingposition whenever the operator desires. o

Another objective is to provide such an irnplement that is compact and otherwise suitable for abrading irregular and/or small surfaces, particularly when in places that are diicult of access with ordinary abrading devices.

Briefly, the present invention provides a device or implement comprising va body portion having a. backing surface or presser surface adjacent to which abrasive tape may lie when the tape is in abrading position and which bears or presses against the back of the tape when the tape is being pressed or applied by the implement against an object (a workpiece) in an abrading operation, and a supply spindle and a take-up spindle rotatably mounted on or in the body, the said spindles being adapted to carry rolls of abrasive tape and being loacted in relation to each other and to the presser surface so that tape may be led from a supply roll thereof on the supply spindle to abrading position adjacent the presser surface and thence to the take-up spindle whereby fresh portions of tape may be brought into abrading position when desired,

The device described and illustrated herein as anvillustrative embodiment of this invention is an elongated abrasive tool of a, shape and design generally resembling that of a large screwdriver in which the flat sides of the outer tip portion or -blade provide the presser or backing surfaces for applying the tape to a workpiece and the shank portion 1s hollowed` out to forin a magazine or chamber for holding a supplyroll and from out of which the tape is led outwardly along one surface of the blade or fingen thence around thev outer tip thereof and thence back along the opposite side to a take-up roll in the magazine.

Figure 1 shows the described abrasive device in use.

Figure 2 is a top elevation or plan view of the finger and the magazine.

Figure 3 is a left side elevation ofthe finger and the magazine.

Figure 4 is a horizontal longitudinal sectional view of the finger and the magazine taken on the line Ill-4 in Figure 3.

Figure 5 is a vertical cross-sectional View of the mazagine taken axially of the forward spindle on the line 5-5 in Figure 3.

Figure 6 is a vertical longitudinal sectional View of the magazine taken on the line 6 6 in Figure 4.

Figure 7 is a vertical cross-sectional view of the forward portion of the magazine taken on the line 1-1 of Figure 3.

The body comprises generally the frame, housing, chamber or magazine II and the attached presser member, blade or finger I2. The finger portion of the body carries a padding layer I3 to provide the backing or presser surfaces I4 and I4' adjacent t6 which the abrasive tape T lies when in abrading position and which bear against the back of the tape when the tape is being pressed by the implement against an object or workpiece, such as the object I5, in an abrading operation.

A supply roll R. of the tape is mounted or wound upon the supply spindle I6 from whence the tape is led out of the magazine II through the opening Il adjacent a guide roll .or shaft I8. thence along the backing surface or presser surface Il of the inger I2, abrasive side out, thence around the outer end or tip of the nger, thence back along the presser surface I4', through the magazine opening I1 adjacent the guide shaft I8' and into the interior of the magazine where it is wound up on the take-up spindle I6' to form a roll R' of used tape.

The rollsfare xed to the spindles Iii-I6 in order that rotation of the spindles, which are suitably journaled in the side wall 24 of the magazine, will wind or unwind the tape. Knurled wheels or thumb-turns Ill-I9' are fixed to the spindles I6-I6', respectively, to provide means for turning the latter.

To provide braking means for holding the tape against motion during an abrading operation, two ratchet wheels 20-20 are xed on the spindles Iii-I6', respectively, each wheel having radially extending V-shaped grooves or notches 2|-2I, respectively, near the periphery on its a side surface facing the wall 24. The notches are adapted to receive the pawls 22-22, respectively,

which latter are xed on opposite ends of a leaf spring 23. The parts of the magazine are positioned so that there is a space between the 3 ratchet wheels 20-20' and the side wall 24 of the magazine II to accommodate the spring. The spring is suitably fixed at its approximate center to the side wall 24 and is sprung or loaded so that its extremities or ends which carry the pawls 22--22' are pressed against the ratchet wheels 20-20' so that whenever a wheel 20 or 2U' turns so as to bring a notch 2| or 2I' opposite a pawl 22 or 22', the pawl will enter and be held in the notch, thereby holding the ratchet wheel and its respective spindle I6 or IB' against turning in either direction. But since the notches are V-shaped in cross-section and the pawls are held yieldably by the spring 23, a turning impulse applied manually by the operator to the thumbturn I9 in either direction, or to the thumb-turn I9' in either direction will unseat the pawl and the corresponding spindle will yield to the rotating impulse of the thumb-turn, thus providing a two-direction pawl and ratchet means which permits the spindles to be rotated in either' direction.

The braking or holding power of the pawls and ratchets are preferably adjusted (by suitable means or design such as depth of notches, strength of spring, etc.) to be sufficient to hold the tape substantially motionless along the presser surfaces I4 and/or I4' during an abrading operation, yet not so great but what they will release the spindles IB--IB' in response to a turning impulse applied manually by the operator to the thumb-turns I9 or I9' in either direction. Provision of a padding I3 on the finger I2 to form the tape-contacting presser surfaces I4-I4', particularly when such padding is one or more layers of cloth or other rough surfaced material that make a good frictional contact with the tape backing, assists in holding the tape substantially motionless during anabrading operation.

The notches 2 I--2I' may be spaced from each other by any suitable distance on the ratchet wheels 20-20, as long as they are close enough together so that a notch will be opposite a pawl when a spindle has turned to draw the tape to a desired degree of tautness along a presser surface. One means for accomplishing this with a minimum number of notches is to space the notches closer together on one wheel than on the other. In the illustrated embodiment the notches 2| on the ratchet wheel 20 are closer together than the notches 2I' on the ratchet wheel 20' (Figure 6). After a length of fresh tape has been positioned along the presser surface I4 by first unwinding it from supply spindle I6 and next winding up the spent portion of tape on takeup spindle I 6 until the slack is taken up, the spindle I6' may then be turned to the point of maximum tautness for the tape along the surface I4' at which the pawl 22- will engage a notch 2|', whereupon the final tightening of the tape may then be accomplished by turning the spindle I6 to the point of maximum tautness for the tape along the surface I4 at Which the pawl 22 will engage a notch 2I.

It will be apparent that the closer the notches are together, the greater the degree of tautness to which the tape can be drawn and held by the spindle with which such notches are associated. Consequently, in the illustrated embodiment, the tape adjacent the presser surface I4 is usually more taut than that adjacent the surface I4', and the surface I4 is therefore usually the preferred backing or presser surface in the illustrated embodiment. However, it is to be understood that surface I4' may also serve as a backing or presser surface; and that either spindle I6 or I6' may be the supply spindle (and the other the take-up spindle); and that either ratchet wheel 20 or 20', whether associated with the supply or the take-up spindle, may carry the closer spaced notches. The notches 2I-2I' need not necessarily be V-shaped in cross-section as long as they and the pawls 22j-22 are shaped in relation to each other so that the pawls will be unseated and will release the ratchet wheels in response to a turning impulse that is manually applied to the thumb-turn I9 in either direction or to the thumb-turn I9' in either direction. If desired, a one-direction ratchet means may be used for a take-up spindle but, whatever braking means is employed, it is preferable that both spindles be rotatable in both directions whenever the operator so desires.

In use, the device may be equipped with a handle or handles suitably attached, as to the stud 25, and employed by applying the finger to an object to be abraded. The illustrated embodiment is shown equipped with a vibrator 26 that is powered through a cable 21. When fixed firmly to the stud 25 the vibrator causes the entire device, including thev nger I2, to vibrate so that manual pressure by the operator of the linger (covered with the abrasive tape as above described) against a workpiece I5 causes the portion of the workpiece thus contacted to be abraded.

The device is thus seen to be particularly adapted to abrading small and relatively inaccessible surfaces, or to abrading small selected areas of large surfaces. An extremely small area can be abraded by application of only the tip end of the vibrating finger thereto.

The finger I2 may be of any suitable size, shape or design as long as it provides a presser surface over which abrasive tape may be drawn and held taut. Or the magazine II may itself be the finger with one or more surfaces serving as the presser surface. The word tape as used herein is a relative term, referring to sheets that are long in proportion to their width, and the principle disclosed herein may be employed to construct devices for using strips or lengths of abrasive sheet material of any width in a wide variety of abrading operations.

Various other alternatives will be obvious to those skilled in the art as usable for the carrying out of this invention without departure therefrom; also it is to be understood that the abrasive finger described and illustrated herein is simply illustrative of this invention, the scope of which is defined only by the claims.

I claim:

1. An elongate abrasive implement for the application of abrasive tape comprising an outwardly extending blade or finger which forms the forward portion of the implement, a handle which forms the rear portion of the implement, an intermediate shank portion hollowed out to form a supply magazine having suitable apertures through which the tape may enter and leave the magazine, the longitudinal axes of the finger, shank and handle being in approximate alignment, the finger having at least one backing surface adjacent to which abrasive tape may be laid to back the tape when the tape is being employed to abrade an object by application thereto of a tape-covered surface of the nger, two spindles rotatably mounted within the magazine, the said nger and spindles being located in relation to each other, to the magazine and to the apertures therein in such manner that abrasive tape may be led from a supply roll thereof on one spindle, outwardly through one of the apertures, along one surface of the finger, around the end thereof, back along another surface of the finger, inwardly through another of the apertures into the magazine to the second spindle, means for rotating the spindles and a braking means associated with each spindle adapted to hold the spindles fixed against turning from the pull of the tape duringV abrading operations and to release them for rotation during operation of the rotating means.

2. The device of claim 1 in which each braking means comprises a pawl and ratchet.

3. The device of claim l in which each braking means comprises a pawl and ratchet means comprising a notched wheel xed to the spindle, a pawl, and spring means for releasably holding the the pawl in a notch, the notches on one ratchet Wheel being in closer spaced relation to each other than are the notches on the other ratchet wheel.

4. An elongate abrasive implement for the application of abrasive tape comprising an outwardly extending blade or finger which forms the forward portion of the implement', a handle which forms the rear portion of the implement, an intermediate shank portion hollowed out to form a Supply magazine having suitable apertures through which the tape may enter and leave the magazine, the longitudinal axes of the ringer, shank and handle being in approximate alignment, the nger having at least one backing surface adjacent to which abrasive tape may be laid to back the tape when the tape is being employed to abrade an object by application -thereto of a tape-covered surface of the finger, two spindles rotatably mounted within the magazine, the said finger and spindles being located in relation to each other, to `the magazine and to the apertures therein in such manner that abrasive tape may be led from a supply roll thereof on one spindle, outwardly through one of the apertures, along one surface of the nger, around the end thereof, back along another surface of the finger, inwardly through another of the apertures into the magazine to the second spindle, means for rotating the spindles separately in either direction and a braking means associated with each spindle adapted to release them for rotation in either direction upon operation of the said rotating means and adapted to hold the spindles fixed against turning in either direction from the pull of the tape to hold the tape taut along the backing surface during an abrading operation.

, 5. The device of claim 4 in which each braking means comprises a two-direction ratchet.

6. The device of claim 4 in which each braking means comprises a two-directional pawl and ratchet means comprising a notched wheel fixed to the spindle, a pawl, and spring means for releasably holding the pawl in a notch, the pawl and notches being shaped and positioned to render the pawls resistance to rotation of the wheel approximately equal in each direction.

7. The device of claim 4 in which each braking means comprises a' two-directional pawl and ratchet means comprising-a notched wheel xed to the spindle, a pawl, and spring means forreleasably holding the pawl in a notch, the pawl and notches being shaped and positioned to render the pawls resistance to rotation of the wheel approximately equal in each direction and the notches on one ratchet wheel being in closer spaced relation tol each other than are the notches on the other ratchet wheel.

8. The device of claim 4 in which each braking means comprises a two-directional paw1 and ratchet means comprising a notched wheel xed to the spindle, a pawl, and spring means for releasably holding the pawl in a notch, the notches comprising radially extending V-shaped grooves on the side of the wheel, the pawl-engaging portion of each notch being approximately symmetrical about an axial plane to render the pawls resistance to rotation of the wheel approximately equal in each direction, and the notches on one ratchet wheel being in closer spaced relation to each other than are the notches on the other ratchet wheel.

9. An elongate abrasive implement for the application of abrasive tape comprising an outwardly extending blade or finger which forms the forward portion of the implement, a handle which forms the rear portion of the implement, an intermediate shank p tion hollowed out to form a supply magazine having suitable apertures through which the tape may leave and reenter the magazine, the longitudinal axes of the finger, shank and handle being in approximate alignment, the linger having at least one backing surface adjacent to which abrasive tape may be laid to back the tape during an abrading operation, two spindles rotatably mounted within the magazine, means for manual rotation of the spindles separately in either direction, and a braking means associated with each spindle .adapted to hold the spindles normally xed, comprising a notched Wheel xed to the spindle, a pawl, and spring means for releasably holding the pawl in a notch, the pawl and notches being shaped and positioned to unseat the pawl and release the wheel in response to manual pressure in either direction through the wheel-rotating means.

10. The device of claim 9 in which the notches comprise radially extending V-shaped grooves on the side of the wheel.

11.. The device of claim 9 in which the notches are in closer spaced relation to each other on one wheel than on the other.

12. The device of claim 9 in which the notches comprise radially extending V-shaped grooves on the side of the wheel, and are in closer spaced relation to 'each other on one wheel than on the other.`

CHALMERS H. RANDOLPH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS l Date