US2190758A - Disk trimmer - Google Patents

Description

Feb. 20, 1940. F, 0, ALBERTSON f l 2,190,758

DISK TRIMMER Filed Feb. 7, 1958 4 Sheets-Sheet ,l

23291 .10. J/@MW @lie/KZ@ @gf/"Zugv Feb. 20, 1940. F. o. ALEERTSDN DISK TRIMMER 4 Sheets-Sheet 2 Filed Feb. 7, 1938 Feb. 20, 1940. F. o. ALBER'rsoN 2,190,758A DISK TRIMMER Filed Feb. 7, 195s sheets-sheet s Invero? (921 jf/"zlzg QJLZ 61275017@ M Feb. 20, 1940. o. N EsER-rscm 2,190,758

DISK TRIMMER v Filed Feb. 7. 1938 4 Sheets-Sheet 4 latente Feb, 20,1940

DISK `'IRIMMER y liransfO.` Albertson, Sioux City, Iowa, assignor to l Albertson `t Company, Inc., Sioux City, Iowa,

a corporation of Iowa f Application February '1, 193s, serai No. 189,037

comms. (01.16443) Thel present invention relates to` disk triml mers, and is particularly concernedwith devices i `for trimmingoff` they edges of the abrasive disks` t of the type which are used on electric sanding machines. w l" Such abrasive disks are usually subjectedto thejmost `wear at that area of the` disk` which is adjacent thev outer edge of the face, and it is that portionof thedisk which becomes iilled with dirt and other foreign material, such as paint, during the` abrading operation. Consequently,

the abrasive disks may be used over and over again by applying them toa smaller `supporting pad, after trimming oit the worn edge.

, One of the objects of the inventionisthe proo vision o an improved `tool by means of `which the used portionl'of an abrasive disk mayybe cut o1.` f Another object of the invention is` the provision of an improved` cutting tool by means of which t, the parts of an abrasive disk maybe trimmedoff and thedisk put in proper position for usegon a smaller `,supporting pad. t .t

1 Another object `of the invention is the provision of animproved disk cutting tool of the `class de` scribed which is simple,` sturdy, economical, and

` Wadaptedto the quick and clean cutting or trim-l `-`vming `of abrasive disks with a minimum amount Y `of` effortnin` order toyutilize fully all of the area ,30" t.,

ofthe abrasive' material. 1 o

Another object ofthe nventionis `the provision "of an improved disk trimmer which is` provided` with, forma-multiplying means lfor increasing `the pressure applied to thetrimmer,` whereby the disk` may be trimmed more quickly and easily. Another objectof theinvention is the provision "of an improved trimmer which has provision for `supporting disks not only of different sizes,` but .1 having different sizesof` centrally located shaft holes. t M o t Another `object of the` invention is ythe provision of anyimproved diskv trimmer] which may be adjustedto standard sizes of disksjvery quickly and to variousother intermediate sizes, with a mini- `mum number` of manual operations.N4

y Another object is `the provision of an improved method of trimming abrasive disksut Other objects andadvantageswill be apparent ofrom the following descriptionand-rthe ccom.. t

l y panying drawings, in which similar characters of t refereneeindicate similar parts throughoutthe several views.

Referring `to the four sheets of drawings accompanying. this` specication,

`1 is a top planview of a disk cutter constructed according to thepresent invention;

Fig. 2 is a side elevational View of the disk cutter;` 1 t 1 Fig. 3 is a full size vertical sectional View; taken through the mechanism of the cutter on the plane of the line 3-3 'of Fig. l, looking in the direction of the arrows;` i t Fig. 4 is a sectional View, taken on the plane of the line ll--d` of Fig. `3, looking in the `direction of thearrows;

5 is a vertical sectional view, takenwon `the plane` of the line 5-5 of Fig.` 2,( looking in the direction of the arrows, showing theydetails of constructionv of the disk supporting trunnion;

Fig. 6 is a viewA similarto Fig. 5, `with the parts of kthe'latter mechanism in a different position;

direction of the arrows; 1; i i

Fig. y`8wis a diagrammatic illustration'ofone form of diskfor whichthe disk cutter is adapted; Fig. 9 is a similar ,viewofanother form of disk;`

of an abrasive disk which has been subjected to `the action of the trimmer, but from which the used portion has not yet been broken off. `The present invention is an improvement over my prior Patent` No. 2,066,381, issued January l 5, 1937,

Referring to Figs. 1-3, 2li` indicates in its en` Fig. 10 is a fragmentary plan view of a `portion l," i

1 i Fig. 7 is a vertical sectionalview, takenon the plane `of the line 1-1 of Fig. 3, looking in the so' i tirety my improved disk trimmer, which is shown in `connection with an abrasive disk 2l, andis carried by a support 22, such vas a table or work bench. lThe trimmer 20 has its mechanism4 sup-l ported upon a castmetal body 23, which `may be substantially 'rectangular in plan, as shown in Fig. 1, andsubstantially rectangular in elevation at each of, the sides thereof, as shown in Figs.

` yto 2`and7., t n The supporting casting or body 2,3,has a pair of side wa1ls2425,`which are provided with 1at` erally Yextending attaching flanges 26,121` having` Y apertures 28 for receiving` the wood screws 29, which secure the trimmer to the table` or `bench 22; Thcbdy `2,3 alsohas a top wall 30,`and referring to Fig. 2, a lett end wall 3l and right end wal132.` 't

The leftA end wall `(see Fig. `3.) extendsdown to the `point 33. The top wall is thickened from 33 to `a vertically extending aperture `34 to provide material forming a bearing 35 for a cutter shaft"36., `The body` is reinforced adjacent the slot 34` b`y` a depending rib 31.` l The slot or aperture 34` Lextendsfronithe bottom to thetop of the body and provides space for the location of the cutter 36, which is carried by the shaft 35.

The shaft 36 comprises an elongated cylindrical member of such size as tobe rotatably mounted in the bearing bore 35. At its right end it is provided With a reduced vsquared portion 3&3 for receiving the cutter 3S; which has a squared aperture lli of the same size. At this end the shaft 36 also has a reduced cylindrical ,threaded portion 4l for receiving a nut 42, which clamps the cutterv 38 in place. f

Washers 43, 44 are preferably disposed on each",y side of the cutterto serve as thrust bearings and tospace the cutter body slightly fromithe vvallofH the slot 34.

The cutter 38 comprisesahardened steelmem'- ber of substantially circular form, which is provided on its periphery (Fig. '7.) ,with a multiplicity of inwardly extending V-shaped slots 45. These slots may be spacedin a random mannerto pro-j. videiknife edge formations 4@ of diierentlength with reSpect to the direction of the Iperiphery of the disk. The cutter ,(E'ig. 3l is SubStantallyIat and of uniform thickness over its central portion, extending to aradius' outside of the washers 143,

V vlill; that "is, to the point'fil; but from the point rthe annular shoulder 54..

The crank 52 may consist of a metal bar which 4'! to the edge of thecutter, the cutter is .tapered as at 48 to a sharp knife edge 46.

The vleft end of the shaft 36 (FigiA 'Ssuppcrts a spacing sleeve #i9 and has a reduced threaded portion 5l! for receivingthe'threaded nut '5|'- and the 'crank 52, which has a threaded 'bore The nut-5I is, therefore, adapted' to actl asj-a lock Washer for securing the crank 52j against maybe slightly offset, if desired,' intermediatejits length, and Which-'is provided with the threaded bore 53 at one end and with a smaller threaded borev 55 adjacent the other end. 'Ih`e s malle` r threaded bore 55 receives the threaded end'of a knob-supporting pin 56,1the .head Fplfof the'pin, l retaining the knob 5? on the 'crank'arm V5l). Thus the'cutter 58 is mounted to rotate with the shaftv 36, and the crank 52 `is vadapted to rotate the shaft and cutter for a purpose further to be ydejg scribed. The rear Wall 32 of the trimmer body` is v .provided with a centrally located horizontally' ex:

tending bore SU for receiving the cylindrical-.end

6l of a .guide bar 62, the restof the guide'bar" being. non-circular y orl rectangular in .crosssection, asshown inFig. 5. A set screw 63 threaded into a' suitable threaded bore in theibottom .of the vvall4 32 is adapted .to secure the bar 62 tothe Wall at substantially right angles thereto'. 'Ihe-gui1.'er bar 62 may'jbe vprovided at 4its outer Yend With Lan additional sup`- v porting foot in the form of a screwmbolt VEidtvvl'iich is threaded into a threaded bore 65 in the .bottom ofthe guide bar at ,its extremeend',` the' screw bolt Sli having itsv headV in engagement witha spacer sleeve 66. The lengthof the s crew'l is the guide bar 62." l The guide bar 62 `may be providedwi-th one or more stop members in the iorm o ffscrevv'bolts 6l, 68, which are located at ythe proper position for the slider ,69 for predetermined; sizesof disks. For example, the stop 61 is at the properposition for a seven inch diskgwhilelstop d8 vislin the proper position for-theslider fora i'lve inch disk, and when the slider 63 is against the wal l ;32; it is inproperposition for. a, three inch disk,v .The numbers 3, 5and7 thusappearon `the top of the then Y.such that .itaidsin supporting" that end o f guide bar s2 adjacent the stops. Naturally, the

screw y68 must be removed vbefore the slider can l be moved overto the three inchposition against the Wall 32. l

The lslider may also be located at ,any intermediate position or any position beyond the stop 6l tothe end of the bar for intermediate sizes of abrasive disks, or for larger disks.

f The-slider supports a shaft or trunnion il) extending upward at right angles to the bar 52.

Slider 69 may consist of a block of metal, such` :fasi steel, which is provided with a rectangular .aperture ll adapted to slidably receivevv the rec- ,tangular or square bar 62. Thus the slider Sli is slidalolyv mounted on the har t2, but is prevented }'rom'.rotatng,:and is heldA upright position. =-"-'Ilheslider lidmay be secured'in any predeter- .mined position by. .means `of a thumb screw '89 which is threaded into a threaded bore @il in slider 69,-.' a'ndthe end of which engages the bar 62.

At its upper side itis provided with a cylindric jbore 72 whichis, adapted'tonreceive vv'ith a tigntfnctipaal' nt the reduced cylindrical end ie ofthe-stubshears. missies shaft 'is is formed with'fa middle cylindrical portion' 'lli and an end cylindrical head l5 of larger size, thus providing theannular shoulder it :for retaining a sleevell on thefshait'v le., The larger vcylindrical portionA l'l5 serves as'atrurinion or'support3for rotatably supporting theablfasive disk 2l, having a relatively small .central aperture it. I'he'present device is, however, adaptedto be used for'sup'port'ing other abrasive disks ld, having' 'a largerfcentrally located apertureV Bil, as s "j'lhe sleevefjl'i isa metal member formed with." I a cylindrical body 8l having afcentrally located' bore 82 for rotating andsliding movement on the shaft 1B, The body '3l has a 'pair of `transverse slots, the slqtjl being relatively shallow, 'while the slotl sglisatlfright angles thereto, and is a.; y

relatively deep slot.

A metal pin @projects laterally` from each lsider of the shaft'lllfand is xedly secured `by al fri'cf tional lit` an aperture in theshait l in such pesitionthatit Will-registerfwith either of the slots 83, BAW/The body Si `of lsleeve i'lhas a revy dueedeyiindrical porties et which' is als@v adapt,-v

edjto servev as a trunnionf oran abrasive disk 179.

cylindrical-portieri 86. l When ,the sleeve ll' Vis in the position'c Fig.v 3, the pin'li.` is' in theslot dit and the proportions and location of .pin and slot are such that the up'-,`

y having anenlarged apertures@ iitting about the perv end Blof sleeve 'il' is approximately on the same plane as the upper 'edge or cutting edgeofA i the cutter 3.8l (Fig. 3). Thus the endfl voi sleeve 'l1 serves as a support for determining .the proper level of the abrasive disk.`

' When the sleeve 'il is lifted so thatthe pin 'emerges from slo't 855, the sleevell` may then be rotated until slot d3 registersvvitli pin'ii, and

` dropped in thatlposinon.' The sleeve is tnen'in the'positionof'l'ig. 63 and thecylindrical portion.`

86 of the sleeve serves asa trunn'ion for the disks (Fig. 9) having the-:larger haies the disk being supported upon the annular vshoulder 88.

i Theannular shoulder *8871s then on a level with theluplOC-rr edge'zof .the cutter 33. U i

Theybodyd of the .disk trimmer isfprovided` with a pair oi"A upwardly projecting. bearing lugs 9i, 92 (see Fig. 1), Figj2 of Whicha-re provided with registeringaperturesy 93 for receiving a bearing pin 94; Whioh .may be riveted.V in rvplace, `or

which may have a tight frictional t in the apertures 93.

The pivot pin 94 pivotally supports a forcemultiplying pressure lever which has its left end (Fig. 3) mounted on the pin 94. The lever 95 may comprise a cast metal member which is provided with a substantially rectangular slot 96 on its lower side, and with a handle 91 which is elongated and extends over both the abrasive disks 2 I.

The lever 95 is provided with a longitudinally extending bore 98, which is in alignment with another threaded bore 99 located at the opposite side of the slot 96. A screw bolt |99 has its head `|9| countersunk in counterbore |92 and has its threaded end threaded into the vertical bore 99.

The screw bolt |99 rotatably supports a soft steel roller |93 which has an outer cylindrical surface |94 located to engage the top of an abrasive disk 2| when the disk `is engaging the cutter 38. The slot 96 is of suficientwidth to receive not only the roller |93, but aplurality of washers |95, and the washers |95 may be used to change the position of the roller |93 when the surface ofthe roller |93 immediately above the cutter 38 has become worn. After long service a groove will eventually wear in the roller |93 above the cutter 38 and retard the cutting. Then one of the spacer washers |95 may be moved'over to the right of the cutter |93, by taking out the screw bolt |99 and replacing it, and then a new surface on the roller |93 will be in position above the cutter 39.

The lever 95 has an end surface |96 adapted to serve as a stop, engaging the sleeve 49 or end of crank arm 59 when the lever 95 is pivoted from the full line position of Fig. 3 to the dotted line position of Fig. 3. In the dotted line position of Fig. 3 the stop surface 99 is supporting the lever 95, which moves far enough so that its weight is shifted from the right side of the pivot pin 94 to the left side thereof inFig. 3. Thus the lever 95 is self-supporting in the dotted line position,

which it assumes when the operator is placing or removing the abrasive disk 2|.

The operation of the present disk trimmer is as follows: l

'I'he sleeve 11 is adjusted to the position of Fig. 5 or Fig. 6, depending upon the size of hole in the abrasive disk 2| or 19. Assuming that disk 2|, with the smaller hole, is to be used, sleeve 'l1 is inthe position of Fig. 3; and with the lever `95 in the dotted line position the disk 2| may be placed upon the trunnion 15. The slider 99 may then be adjusted by loosening the thumb screw 89 and sliding the slider along the bar 92 until `the position of the edge of the disk 2|' with respect to the cutter is as desired; that is, the disk ismoved until it is observed that the cutter will trim off the desiredamount, which, would be the worn or lled portion of the abrasive disk.

The disk is applied to the trimmer with its abrasive side up, so that the cutter engages `the smooth or paper side of the abrasive disk 2|. The roller |93 engages the abrasive side of the disk.

The operator then applies pressure to the roller |93, which in turn engages the abrasive disk and forces it against the cutter 38. This pressure is applied by pushing down on the hand lever 95. A considerable amount of pressure may then be applied with a minimum amount of effort, due to the location of the cutter adjacent the point of pvot 94, and due to the length of the hand lever 95. i

With the pressure thus applied, the operator rotates the crank 52 with his other hand by means of knob 58, thus also rotating the shaft 36 and the cutter 38. The cutter teeth or knives 9 bite into the ber or base material of which the abrasive disk is constructed and serve to cause the abrasive disk to rotate on the trunnion 'l5 as the cutter rotates, the teeth in effect forming their own interlockingdepressions inthe bottom side of the abrasive disk.

Depending upon the thickness and toughness of the abrasive disk backing, the disk may be r0- tated once, twice, or more times, the knives 46 s cutting in more deeply on each successive rotation, but it is generally only necessary to eiect one rotation of the abrasive disk 2|, during which the knives will produce aplurality of spaced cuts in the lower side of the abrasive disk, as shown in Fig. l0. These spaced cuts practically go through the backing and abrasive facing of` the, disk 2|, but the trimmed edge may still be retained on the abrasive disk and may then be removed by a tearing operation along the dotted and punched line |91 (Fig. l0).

During the rotation of the abrasive disk the roller |93 rotates but serves as a backing for pressing the abrasive disk against the cutter.

The disks may thus be trimmed neatly and cleanly with a minimum amount of effort and again used on a supporting pad of smaller size so as to utilize all `of the area of the abrasive disk down to the smallest size, which is approximately three inches.

Myimproved method of trimming abrasive disks comprises pressing the rear side or backing of an abrasive disk against a knife and cutting in said rear side of the abrasive disk a plurality of spaced indentatons. 'This may be done by feeding the disk to the knife in a rotary direction, and thereafter the trimmed portion may be broken or torn from the disk to effect a clean cut s `size of abrasive disk and to one or more sizes of centrally located abrasive disk apertures. It is adapted to be used for a longer period of time without dulling the cutter, and greater pressure may be applied tothe disk and cutter with less effort, so that the disks are trimmed much more quickly than by means of the prior art devices.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my inventiorn what I claim as new and desire to secure by Letters Patent of the United States, is:

l. In a trimmer for abrasive disks of the type having a centrally located aperture, the combi* nation of a base adapted to be secured to a fixed support, said base having a transversely extending bearing and a drive shaft in said bearing, a crank carried by the outer end of said shaft, and a cutter wheel carried by the opposite end of said shaft and iixedly secured thereto, said cutter wheel having a sharp peripheral edge separated by a plurality of slots forming radially projecting knife-like teeth adapted to engage in the back of a .disk to fformiindentations drive :the ldisk, and ,a support for the fdisk comprising a guide member carried ,by said baseand projecting substantially parallel to said shaft, said guide member being provided with a slider, and said slider being adapted to be 4received in the aperture of said disk for rotatably supporting the disk, said base Ihaving a pressure lever pivotally mounted thereonabove said shaft, .said pressure lever overhangingsaid trunnion .and being provided with a cylindrical pressure roller located above said cutter and rotatably mounted upon a shaft eX- tending substantially parallel to the cutter shaft when the roller is engaging a disk whereby a disk may be located on said trunnion, with its abrasive side engaging said roller, and by rotating said crank and pressing downward on said lever said Cutter will dig into the back side of the abrasive disk to f orm indentations and the teeth of said cutter will drive said disk, causing it to rotate about said trunnion, said roller forcing said disk against said cutter without bringing the cutter into engagement with the abrasive, whereby the indentations form a circular line about said disk, and the part of the disk outside of that line may be broken 01T by the hand, the length of said lever being such that suificient force may be applied to the rear side of an abrasive disk with the cutter, without forcing the cutter through the abrasive and into engagement with the roller.

2. In a trimmer for abrasive disks of the type having a centrally located aperture, the oornbination of a base adapted to be secured to a. fixed support, said base having a transversely extending bearing and a driveshaft in said bearing, a crank carried by the outer end of said shaft, and a cutter Wheel carried by the opposite end of back of a disk to form indentations and drive v .the disk, and a support for the disk comprising a guide member carried by said base and projecting substantially parallel to said shaft, said guide member being provided with a slider, and said slider being adapted to be received in the aperture of said disk for rotatably supporting the disk, said base having a Vpressure lever pivotally mounted thereon above said shaft, said pressure iever overhanging said trunnion and being provided with a cylindrical pressure roller located above said cutterr and rotatably mounted upon a sha-ft extending substantially parallel to the cutter shaft when the roller is engaging a disk whereby a disk may be located on said trunnion, with its abrasive side engaging said roller, and by rotating said crank and pressing downward on said lever said cutter will dig into the back side of the abrasive disk to form indentations and the teeth of said cutter will drive said disk, causing it to rotate about said trunnion, said roller forcing said disk against said cutter without bringing the cutter into engagement with the abrasive, whereby the indentations form a circular line about said disk, and the part of the disk outside of that line may be broken off by the hand, said roller shaft being provided with a plurality of vspacers mounted thereon, whereby the position

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