US 2871630 A
Description (OCR text may contain errors)
Feb. 3, 1959 J. B. wHlTLocK POLISHING FILE Filed May 22, 1957 United States j This invention relates to hand files and more particularly to an improved hand polishing tile featuring means for clamping readily replaceable strips of abrasive material in `place together with'means for tensioning such strips as found most suitable for'the work at hand.
There has been proposed heretofore hand files having means by which replaceable strips of abrasive material may be clamped to a suitable holder. However, devices of this type as heretofore provided have serious shortcomings and disadvantages'obviated by this invention. For example, the means provided in prior files for securing the opposite ends of the abrasive strips to the holder and for thereafter tensioning the strips are complex in construction, difficult for the novice to use and the stripe clamping arrangements are unreliable.
The construction provided by the present invention sat. isfactorily overcomes the-foregoing and other disadvantages of prior files in an unusually satisfactory manner. The elongated main body of the holder is provided with a simple self-gripping clamp at one end which acts to clamp the adjacent ends of the two strips to the holder. The combined strip clamp and the strip tensioning means provided at the rear end of the ho-lder co-mprises a single operating handle serving normally as the handle for the holder and operating by rotation in opposite directions about its own axis to release or to tension the two strips simultaneously depending on the direction in which the wat handle is rotated. Featured is a spring which automatically increases the gripping action on the strips as the tension is increased. Additionally, the single clamping member at the remote end of the holder acts automatically to increase its gripping action as the tension is increased on the abrasive strips.
Accordingly, it is a primary object of this invention to provide an improved polishing le having simple means for replaceably clamping one or more strips of abrasive material therein.
Another object of the invention is the provision of a hand held polishing file having a simple easily operated clamp at its end for detachably clamping one or more strips of replaceable abrasive material to the holder, one of the clamps being effective to tension the strips of abrasive material.
Another object of the invention is the provision of a polishing tile which can be assembled from simple, inexpensive and easily manufactured components without need for jigs, dies and other special manufacturing `facilities.
These and other more specific objects will appear upon y Figure 2 is an enlarged central longitudinal se'cqlal l view taken on line 2 2 of Figure 1;
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Referring to Figures 1-3 there is shown a polishing le j vdesignated generally 10 having a main body 11 with flat opposite sides of a suitable width depending upon the use to which the file is to be put. This body may be formed of wood, plastic or of lightweight metal. The clamping facilityl prov1ded at the forward end preferably comprises a slot extending crosswise of the main body and having the configuration best shown in Figure 1 and including a narrow portion 12 opening into a wide based portion 13 the oppo-site sidewalls 14, 14 of which converge toward the relatively narrow mouth 15. Seated within narrow portion 12 is a strip of soft rubber or other elastic material 16 the forward end of which terminates close to the plane of mouth 15 and having sufficient clearance from sides 14 as to permit the insertion of the ends of abrasive strips therepast. A suitable keeper 17 conveniently provided by a round wooden dowel pin 17 has a diameter appreciably greater' than the width of mouth 15 and resiliently urged toward this mouth by elastic strip 16. As is shown in Figure 2, keeper 17 has a length corresponding to the lWidth of main body 11 so that its ends do not project beyond the edges of the main body yet are conveniently accessible to the tips ofthe users thumb and indexiinger so thaty pressure can be applied to the opposite ends when compressing strip 16 sufficiently to permit the withdrawal and insertion of the'ends of the abrasive strips. l v
TheV` releasable clamping means provided at the rear end of-main body 11 comprises a handle grip 20 having a central bore" 21 loosely receiving a long bolt 22 the threaded forward end of which is threaded into a bore 24 prevent unthreading of these components.' lt will be` understood that bolt 22 likewise has a tight iit with threaded bore 24 and is turned into this bore until the forward lend of sleeve 25 bears lightly against end wall 26 of the main body, a washer or suitable low friction devicebe'ingl inserted ifdesired between surface 26 and the endof thimble 25. Accordingly, it will be understood that hand grip 26 and sleeve 25 are free to rotate about the stationary` mandrel or support provided by the body of bolt 22. f
The clamping device forv the adjacent ends of the abrasive stripsv comprises a pair of at jaws or plates 28 and 29 having their facing surfaces lying close together and forming the abrasive gripping surfaces of the clamp. The threaded opening centrally'of jaw plate 28 mates with the threads on sleeve 25, whereas outer plate 29 has a slightly larger smooth opening 30 slidable freely along sleeve 25. Astiff compression spring 31 encircles sleeve 25 with one end bearing against plate 29 and the other end bearing against a washer 32 at the forward end of hand grip 20.
Suitable means are provided for preventing the clamping plates 28 and 29 from rotating as sleeve 25 is turned, as, for example, a pair of guide pins extending loosely through aligned openings 34 in plates 28` and 29, these pins being anchored in'recesses 35 in the main body of While a pair of guide pins 33 are here shown and are preferred, it will be appreciated that a single pin may be used.
Strips of abrasive material 37 and 38 are' shown as mounted along the opposite sides of main body 11. Such strips may-have either a paper or a fabric backing and a face covering of abrasive powder or grit secured thereto by a. suitable bonding agent. These strips have a width grinding with the second strip merely -by reversing "the position of the `tile with respect to the surface being iinished.
The manner in which the abrasive strips are mounted will be quite apparent from the foregoing description lof the file construction. lTwo strips 37 and 38 of abrasive materialare cut to suitable equal lengths and the opposite ends are foldediover or sharply creased transversely of the strips as along transverse lines 39 and 40, these two crease lines being equally spaced apart Vlongitudinally of the strips. Hand grip 2i) 'is rotated -in a direction to thread plate 28 toward the `rear end of the main body thereby relaxing the compressive Vforces acting Von spring 3l. In this position, the Vrear ends of the strips may be readily withdrawn from the clamping plates.
The forward ends .of the strips are released by grasping the end yof keeper dowel 17 .between the thumb and fore-linger and pulling it backwardly compressing elastic strip 16 thereby releasing the forward ends of the abrasive strips from groove i3. Dowel pin .17 is lsimilarly held retracted while the creased tabs of a pair of lnew abrasive strips are inserted against the side walls '14 of clamping groove i3. When properly positioned against walls 14, the dowel is released allowing rubber strip 16 to press the dowel toward the mouth of the groove thereby wedging the Strips firmly lagainst the groove `side walls.
The turned over rear ends of Ystrips '37, 38 arev the'n itted between clamping plates ,23 and 29 and held `in PlaC therein by :light finger pressure as Vhand grip '2li lis rotated wto thread plate ,28 along sleeve 2 6 toward the hand grip as spring .3l is compressed toforce plate 29 into firm gripping `contact with the strip ends. Further rotation of the hand .grip increases both the clamping pressure on the strip ends as well as the tension on the strips, the rotation of the grip being discontinued when the strips are ata desired'tautness. The le is now ready for use and may be ,employed in the usual .manner to abrade and then polish surfaces of metal, wood, plastic o r the like.
While the particular hand polishing file herein shown and disclosed in detail,y is ful-ly capable of attaining the objects and ,providing the advantages `hereinbefore stated, it is to be understood that Vit is merely -illustrative of the presently preferred embodiments of the invention and that no limitations kare .intended tor-ther details of construction vor design herein vshown other than yas defmedin the appended claims.
`1. A hand file adapted Vfor .use with replaceable strips of abrasive material, said 'tile comprising a'rigd backing member having a hand grip rigidly` and adjustably secured to one end thereof, means at 'the 'opposite'fends of said rigid member for releasably kclamping the `opposite ends of a strip of abrasive material therein, and-means operable by rotation of, said hand grip independently of ysaid clamping means for adjusting :the tension on said strip Vof abrasive material longitudinally thereof. t
2. A hand iile as defined 'in .claim `l including a plurality of strips of abrasive material releasably 'supported along the opposite flat surfaces of said rigid imemberfea'ch adapted to be itensioned simultaneously by Vthe adjustment of said hand grip.
3. A handfiile as ydefined in claim l wherein the means for holding said abrasive. strip ,to the forwardend of said rigid member comprises a groove acrossthetend `of said member, and self-clampingresiliently backed means seated in `said groove operable to clampthe end yof an abrasive strip releasably in place in said groove.
4. A hand file adapted to support a pair of abrasive strips stretched taut flat against an elongated rigid backing member, said backing member having wide dat surfaces on the opposite sides thereof, a groove across one end of said backing member having side walls converging toward the entrance end thereof, a clamping member loosely supported lengthwise of said groove and having a width greater than the mouth of said groove, resilient means urging said clamping member toward the mouth of the groove and being effective in cooperation with said clamping member to clampv the ends of abrasive strips against the side walls of said groove, and means at the opposite end of said backing member for clamping and tensioning the opposite ends of strips of abrasive material extending along the at sides of the backing member.
5. A hand iile as defined in claim 4 wherein said means for tensioning strips of abrasive material'includes a hand grip rotatably secured to the end Vof said backing member, and means controlled by the rotation of said hand grip in one direction to tension strips of abrasive anchored to the groovedtend of said backing member and operable to slacken said abrasive strips when vrotated in the opposite direction.
6. A `hand file for use with replaceable strips of liexible abrasive material, said file comprising a long iiat back-ing member having a narrow mouthed groove across one end, said groove being adapted to seat the ends of abrasive material, `resilient self-locking means manually depressible to receive the ends of abrasive strips and for automatically clamping the same in place in said groove, a hand grip rotatably supported at the other end of said backing member, resilient clamping means operatively associated with said hand grip for clamping 'the adjacent ends of abrasive strips, said hand grip be'ing 'rotatable to effect displacement of said/clamping means relative to said 'backing member to tension said strips lengthwise off'said backing member when rotated' in one direction andvto relax the tension on said str-ips when rotated in Vthe everse direction.
7. A hand iile as dened in claim 6, said resilientclamping means including a pair of clamping plates, threaded means rotatable with said hand grip and passing freely through one plate into threaded engagement with the other plate, and spring means interposed between said hand grip and said one plate for urging said plates together.
8. A hand lile as defined in claim 7 including guide pin means anchored to the end portion of said backing member and extending through openings in said plateslaterally offset from said threaded means and parallel thereto.
9. A hand tile for detachably clamping a liexible strip of abrasive material stretched taut along an elongated backing member, a handle mounted at one end of saidl member and rotatable about its longitudinal axis, a threaded sleeve fixed to said handle and having its 'endr0- tatablygsupported adjacent the handle end of said backing member, a pair ofclamping plates mounted on 'said sleeve one plate having threaded engagement with `said sleeve and the other being loosely journaled thereon, and spring means urging said loosely Jiournaled plateagainst the other plate to grip tightlyvone end of an abrasive strip extending along said backing member. f
l0. A hand `file as defined in claim 9 includiugjstationary guide means iixed to said backing member and extending through guide passage means on said plates tohld the same against rotation with said sleeve'an'd said'handle as the latter are rotated to tension and slacken an abrasive strip, said guide means having one end anchored "to said backing member.
11. A hand tile for detachably supporting a flexible strip of abrasive material stretched taut along the iiat surface of a backing member, said backing memberhaving clamping and adjustable tensioning means at one Aend thereof adapted yto -grip vfirmly one end of an vabrasive asamso strip, and means for releasably anchoring the strip to the opposite end of the backing member, said anchoring means including a groove across the end of backing member, the side walls of said groove converging to a narrow mouth, a keeper extending along said groove and freelf.y movable therein but having a Width greater than the mouth portion of said groove, and resilient means urging said keeper toward said groove mouth and eective in cooperation with said keeper to wedge the end of an abrasive strip between said keeper and one Wall of said groove.
l2. A hand lfile as dened in claim l1 wherein said backing member has a pair of flat surfaces along the opposite sides thereof and parallel to the longer axis of said References Cited in the le of this patent y UNITED STATES PATENTS 1,274,928 Mauer Auge, 191s FOREIGN PATENTS 201,977 Great Britain Aug. 13, 1923