US1910658A - Abrasive reamer - Google Patents

Description

May 23, 19 33.

6. w. TYDEMAN ABRASIVE REAMER Filed July 15, 1929 Patented May 23, 1933 UNITED STATES CLARENCE w. or anernwoon,

COIiOBADO, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO A. OBERHOLTZ, JR, OF DENVER, COLORADO ABBA SIVE REAMER.

Application filed July 15,

My invention relates to abrasive reamers and is an improvement over my formerinventions applied for August 6th 1928 and September 28th 1928, the serial numbers being 297 ,603 and 308,986 respectively.

' my former inventions there was no quick, positive and reliable method for changing the reamer size beyond the range of its adjustment by the substitution of shoes or blades of a difi'erent size.

This made it necessary for a shop to have several diiierent sizes of reamers. There was also no accurate, delicate and reliable adjustment of the reamersize in fractions of a thousandth part of an inch which the precision of the device warranted in actual service, and the shoes or bladeswere not supported for their full'length, which resulted in slight springing of the shoes or blades when the operator forced the enlarging adjustment too vigorously, resulting in a slightly out of parallel or bellshaped hole. p The object of mypresent invention is to provide an abrasive reamer construction in which shoes or blades of widely different diameter or size may be substituted quickly and conveniently, so that but one reamer is required, in which any desired size of blades may be set. r

A further object of my present invention is to provide anabrasive reamer construction having a diametral expansion which can be accurately and reliably gauged by a micrometer adjustment to a small fraction of a thousandth part of an inch.

A further object of my invention is to provide an abrasive reamer, .the expanding shoes or blades of which are rigidly supported for substantially their entire length so that the reamer will finish a hole exactly parallel even if it is forced or crowded by the workman.

I attain the above objects by (providinga constructionhaving two oppose channeled 1 body being maintained by a fixed tapered 1929. Serialflb. 378,332.

shoes or blades adapted to receive sheet abrasive and closely'and slidably fitting for their full lengths upon opposite sides of atapered central body, their position on the cup keyed and longitudinally movable at the small end of the tapered body, and by a resiliently held floating tapered cup at the large end of the tapered body, and the di-. ameter of the hole reamed being adjusted by the position of the shoes along the tapered body as determined by a micrometer adjustment in which the enlargement of the tapered body per inch of length is properly combined with the threads per inch and the divisions of an adjusting nut on the threaded end of the tapered body, thenut bearing against and longitudinally positioning the solidly held tapered cup against the shoes and the resiliently held tapered cup.

All of this is clearly described below'and isillustrated in the drawing, in which Figure 1 is anelevation in partial section, of my abrasive reamer.

Figure 2 is an elevation in partial section of Figure 1, taken from above.

Figure 3 is an end view of one of the shges or blades, as seen from the floating cup en Figure 4 is a view of the other end of one of the blades or shoes, that is, as seen from the fixed cup end. v

Figure 5 is an end view of the body.

Figure 6 is an end view, in perspective, of one of the sheet abrasives in the position it assumes when mounted on a shoe or blade. I

Figure 7 ,is an enlarged fragmenta section of the body on the line 77 of igure 1, showing a-modified section contour, and in dotted lines showing in an exaggerated way the position of a shoe on the body when in Ijoperation. n1 (1 fi v igure 8 is an e arge agmenta' section similar to Figure 7 and showing a ihodi- 90 fied from of'contour for the ta ered faces 6. The body 1 is provided wit the driving shank 2, which is connected to the mount- The extenslon of the'small end 8 is provided with the thread 9 and the keyway 16.

163s such that when the device is set at its The driving shank 2 has a hole for the reception of the pin 11 which fits in the hollow of the washer 12 and holds it against the pressure of the spring 13.

The spring 13 contacts with thefloating tapered cup 14 and forces it against the and the shoes 16 acts to hold that end of the shoes together and with their tapered .contact against the tapers 6. of the body 1,-

tapered ends ofthe shoes 16, upon which are mounted the abrasive sheets 17, as will be described below. I

The tapered contact between the'cup 14 faces 18 in contact with the tapers 6 of the body 1.

The fixed tapered cup 19 by its contact with the tapered faces 20 of the shoes 16,

acts to hold them together and in contact with the tapers 6 of the body 1. The sides -16 of the guide channels of the shoes 16 have a close slidable fit against the fiat sides 5 of the body 1. The key 21 of the fixed on 19 fits in the keyway 10 and is thereby he d from turning with respect to the body while permitting longitudinal movement of .the cup 19 thereon.

The knurled adjusting nut 22 is in close threaded engagement with the threads 9 of the body 1, and bears against the fixed cup 19, thus positioning the cup 19, the shoes 16 and the cup 14 against the pressure of the spring 13.

Adjustment of the nut 22 on'the threads 9 adjusts the position of the shoes 16 upon the tapers 6, and thereby adjusts the diameter of the hole reamed by the reamer. When it is desired to replace the' shoes withshoes of difierent size, the floating cup .14 is pushed along the shank 2 againstthe pressure of the spring 13 till it releases the tapered ends 15 of the shoes, which per- .mits the shoes to be withdrawn from the fixed taperedcu 19. The new shoes are put 1n place by rst inserting their tapered ends 20 1n the cup 19, bringing the shoes together till the body 1 fits into their longi-- tudinalchannels and their tapered faces 18 and then permitting the spring 13 to push the floatin on 14 into place where it holds the tapere en s 15 of the shoes together and holds them firmly upon the tapers 6 of the body 1. g

The sheet abrasives 17 ofthe size corresponding to the shoes or blades in use, are

mounted upon the shoes or blades 16 by being bent to the position shown in Figure 6, and are then slipped upon the shoes endminimum size adjustment with a'certain size of shoe, the main contact on the abrasive will be at the sides as at A and A ure-7 and as the setting changes toward the maximum size the main contact will move toward the center of the shoes as at E and E.

In order that the adjusting nut 22 may act as a delicate and accurate micrometer gauge for the diameter of hole finished by the reamer, the following construction is used The angle of the tapers 6. of the body 1 is such that they separate at the rate of seventy thousandths of an inch (.070") to each axial inch.

The threads 9 have twenty, eight (28) threads to the inch, so that it takes 28 turns of the nut 22 to enlarge the reamer size seventy thousandths of an'inch. Then, one turn of, the nut 22 will open the reamer 1/28th of seventy thousandths, or two and one half thousandths-of an inch.

- The cup 19 is provided with the zero mark 27 adjacent its contact with the nut 22, and the nut 22 is divided by the marks 28 into 25 equal divisions. i

That is, one division is one twenty fifth of a turn for the nut 22, or one twenty fifth of two and a half thousandths, that is, one ten thousandth part of an inch.

As the divisions on the nut 22 are roughly an eighth of an inch apart, this permits a careful'workman to approximate the proper distance from the nearest division mark and with fair certainty make an adjustment of say one fourth of a division, or one fortieth of a thousandth part of an inch. It is not meant that the ordinary workman can work this close, but this delicateadjustment does provide means whereby a workman can 'udge how much to turn the nut 22 when ma ing the last finishing touch to a fit, when there is perhaps 'ust a little too imich drag as the pin'is pus ed throughthe It also permits a workman to finish a. hole, note the setting of the nut 22, reduce the size of the reamer by backing off the nut 22 till the reamer will come out of the hole without .cutting or scratching, and then on the next hole the known former setting will insure his not adjusting the reamer to a greater size than the precedin hole, if a little care is used, and if he s ould be careless of Figtire division it would mean a variation of but one tenth of a thousandth of an inch in the hole size.

In fitting the pistons and connecting rod ends (when floating pins are used), all of the holes may be roughed out to within a thousandth of an inch of the required size, say, by the aid of this micrometer adjustment, and then the last finishing fit may be easily and quickly made for pin by individual fitting.

In this connection it may be stated that the life of the abrasives is quite surprising.

In one well known make of V-eight automobile engine, the eight pistons and the eight rod ends were rough fit to the same micrometer setting, just to note the amount of wear on the abrasives.

It was found that the greatest variation in size, that is, that between thelargest hole of the 16 holes, and the smallest hole, was

7 one half'of a thousandth part of an inch.

chosen for the body 1, different The pins on the same engine were then measured and were found to vary from the largest to the smallest by six tenths of a thousandth part of an inch.

This gives a comparative indication of the extreme accuracy afforded by my reamer .with this micrometer adjustment and the full length supports for the shoes.

I am aware thatdiiferent tapers may be threads per inch may be employed and a different-number of divisions may be marked upon the nut 22, but in any case the result will be the samein that the spread per axial inch of the tapers combinedwith the number of threads per inch of the adjusting nut give the variations in reamer diameter corresponding to the parts of an inch indicated by the divisions on the adjusting nut.

In Figure 5 it will be seen that when the reamer is turned in the direction indicated by the arrow, the tapered faces 18 of the body 1, are beveled as at 29; that is the lagging corners are beveled.

The reason for this will be more clearly understood by the exaggerated view shown in Figure 7.

- In this enlarged view, the rotation as indicatedby the arrow D is in the same direction as in Figure 5, but the beveled faces 29 are replaced by the faces 30 of curved-contour. 4

. In either case, the main point is that the leadingcorner of the tapered faces 18 is full, and the lagging corner is relieved.

The contour and the amount of this relief may depend upon several conditions, but the reason for such relief isas follows In my experiments with my reamer it was found that -if the shoes were .very closely fitted upon the body, the reamer worked perfectly, did not chatter nor lock in the hole,

each individual and there was apparently no reason at all to suspect possible trouble.

But, it was also found, that if, in the course of mass production the shoes were fit the least bit too freely upon the body 1,

a looking or clutch efl'ect, or a chatter was 7 When the reamer is adjusted till contact with the wall of the hole occurs, say at the point A on the abrasive 17, there is a tendency for the friction thus developed to move the shoe 16 in a direction opposite to the arrow D, with respect to the body 1.

If there is a little play between the body 1 and the shoe 16 this movement between the two will take place about the point 31, say, as a center, andthe contact point A will temil to follow the curve B dueto the radius In other words the action is that of a fillitch which locks-the reamer tight in the o e. r

If, however, the corner 31 is relievedalmost to the corner 32 as shown, the point A will tend to revolve about the corner 32 as a center with the radius R and will follow the curve C.

The proportions of Figure 7 aremuch exaggerated, since in actual use the matter concerns at most a few thousandths of an inch, and it is found that the corner 31 need not be relieved more than about half way tothe corner 32 under most conditions,- but .the exaggeration only tends to make-what happens more clear.

With the construction shown in Figure 7 the reamer willoperate perfectly when-revolved in the direction of.the arrow D, but will lock tight in the hole when revolved in the opposite direction.

The diameter of the hole being reamed, the thickness andthe width of the body 1, and the outer contour of the shoes 16 are all of them factors which combine to determine What amount of the lagging corners of the tapered faces of the body 1 should be removed, or how close to their leading corners the faces 18 should be relieved. This matter of proportion can be readily deter mined by trial by any intelligent mechanic,

'once he is aware that the lagging corner must be relieved enough to prevent the lock action mentioned, or to prevent chattering.

If it is desired to build a reamer that can be revolved in either direction, then both corners of the taper faces 18 must be considered lagging corners, since one will be lagging when the reamer is revolved in one direction, and the other will be lagging when the reamer is revolved in the other ditouch the sides 6 of the body.

rection.

In this case, with both corners relieved, the tapered faces 18 will be reduced to little more than a line midway between the two corners.

This is illustrated in Figure 8, in which the similar contours 33 intersect on the tap ered face 18 in the center of the body 1.

Since this construction from a practical standpoint is slightly more difficult to make,- and since there is no particular advantage in a reamer that may be revolved in either direction, I prefer the construction shown in Figures 5 and 7, though any mechanic will appreciate that the construction best suited from all standpoints to the particular case in hand, should of course be employed.

The followingmay be stated as further explanation of the reason for the relief of the body 1 as at 29 or 30;

If there is any play between the shoe and the body it has been found by actual test that the instrument will chatter or look unless the lagging corners of the faces 18 are relieved. It can be seen that when the tension is applied and the reamer is snug in the hole the shoe will tend to hang back and twist or cook with respect to the body until the sides 16' of the shoe guide channels touch the body sides 5 and the faces 18 of the shoes If the play between shoes .nd' body is such asto permit enough of this twisting or cocking movement between them, the clutch efi'ect mentioned above is produced.

My reamer is not necessarily limited to a two blade or shoe construction, since any other number of blades may be employed if desired, so long as they are supported for substantially their entire length and are adjusted by a proper micrometer adjustment. So, I do not mean to confine the construction narrowly to a two blade or shoe construction.

Actual tests, however, have shown that a two shoe or blade reamer is just as efficient as one having more shoes or blades and it is of course cheaper to manufacture.

Having now described my invention, what I claim as new, and desire to protect by Letters Patent, is as follows.;

1. In an adjustable abrasive hole-finishing cutting tool, a central body having parallel sides joined by tapered facesi forming a tapered portion having a small and a large end and provided with 'a threaded portion extending from the said small end and a driving shank extending from the large end, a mounting shank, means forming a universal connection between the mounting shank and the driving shank, a cupon said driving shank facing said large end, resilient means longitudinally positioning the cup against the said large end, shoes provided with abrasive members fitting upon said body and radially positioned by said tapered faces and at the said large end adapted to extend into said cup and be thereby held upon said body,

a cup on said threaded portion and adapted holding them upon the said body, a spring positioned upon the said body and bearing against one of said cups, and an adjustin member threadedly engaging said body an adapted to bear against the other cup.

3. In a, cutting tool having a central ody with faces tapered aredetermined part of an inch per axial inc and shoes provided with abrasive members fitting thereon and contacting, said tapered faces for substantially their entire lertiigth, cups fitting the ends of said shoes an thereby holding the shoes in place on said body, a spring positioned upon the said body and bearing agamst one of said cups to hold it against the shoes, an adjusting member threadedly engaging the said body by a predetermined number of threads per inch and in contact with the other cup and adapted to position it and the shoes against the pressure of the first cup and said spring, the adjusting member and adjacent cup acting as micrometer members, one of which carries an index mark and the other of which is provided with a plurality of marks equally spaced to combine with the taper of said tapered faces, and the threads per inch of said engagement between the body and the adjusting member to indicate a predetermined part of an inch per division of movement of one of said micrometer parts with respect to the other..

ly position the other cup, and adjust the diameter of said tool by change of the axial position of said shoes upon said body against the pressure ofsaid spring.

5. In a cutting tool having a threaded cem tral body with tapered faces and shoes provided with abrasive members fitting thereon,

cups fitting the end of said shoes and thereby holding them upon the said body, a spring positioned upon the said body and bearing against one of said cups, theother cup having a guided axially movable engagement with said body and an adjusting member in threaded engagement with the threads of said body and bearing against the guided cup, the cup and the adjusting member acting as micrometer members one of which carries an index mark and the other of which is provided with a plurality of equally spaced division marks, whereby the movement of the adjusting member one of said divisions combined with the pitch of said threads and the angle of said tapered faces will move the shoes axially on said body and thereby vary their diameter a predetermined part of an inch.

3.6. In a cutting tool having a threaded central' body with tapered faces and shoes provided with abrasive members fitting thereon and having contact with said tapered faces for substantially the entire length of said shoes, cones fitting the ends of the said shoes and adapted to thereby hold them upon said body, a spring carried by the body and hearing against one of said cones, the other cone having a guided axially movable engagement with said body and acting as a micrometer part, and an adjusting member threadedly engaging said body and bearing against the guided cone and actmg as another micrometer part, one of said parts pro vided .with an index mark, and the other part provided with a scale of equal divisions, whereby the movement of said adjusting member one division will axiall' move the shoes and vary the tool diameter termined part of aninch.

7. In a cutting tool having a central body with tapered faces, abrasive-supporting shoes internally tapered to fit said tapered faces of the body, two cups 011 the body in contact with the ends of said shoes and holding them upon said body, a spring supported on said body and bearing against one of said cups, and means 'on said body positioning the other cup against the pressure of 8. In a cutting tool having a central body with two opposed ffaces joined by two sub stantially parallel faces and having abrasive-supporting shoes fitting thereon, cups internally tapered and fitting over the ends of said shoes mounted upon said body and thereby holding the shoes on the body and a spring positioned upon said body and bear- 1ng agamst one of said cups to hold'it in resilient contact with the adjacent ends of the said shoes. r

9. In a cutting tool having a central body with tapered faces and having an abrasive supporting, bevel-ended shoe fitting upon each tapered face, two internally, tapered, I

tapered side walls, a pair of shoes adjustably mounted on the shank body and having inner inclined faces tapered reversely to the tapered faces of the shank body, a nut threaded on said threaded end of the shank, an enlarged annular collar confining the lower ends of the shoes adjustable by said nut, a collar slidable on the upper end of the shank having an enlarged annular flange confining the upper ends of the shoes, a coil spring on the shank engaging the collar, means on the upper end of the shank engaging' the spring to place the same under tension and hold the collar engaged with the shoes, an abrading sheet inclosing the shoes, alrlid means for retaining the sheeton the s oes.

11, A cutting or abrading tool comprising a body member of substantially rectangular cross section, two substantially identical abrasive supporting shoes, each shoe having a rectangular guide channel extending longitudinally thereof, said guide channels being of the proper size to receive the edges of the body mem er, the body member serving as a means for rotating the shoes about its longitudinal axis, the lagging corners of the body members being chamfered, and means for holding the shoes in place on the body memr. 12. A cutting or abrading tool comprising a body member having a substantially rec-. tangular body portion whose edges are equally inclined with respect to its longitudinal axis of syminetry, two substantially identical abrasive supporting shoes, each shoe having a rectangular guide channel whose bottom is inclined with respect to the ios beveled edge, abrasive-supporting shoes internally tapered to fit said tapered faces and two cups on the body in contact with the ends of the shoes and holding them upon said body, the cups being movable in the direction of the length of the body to posi-- tion the shoes for the purposeof adjustment and for holding them in adjusted position.

14. In a cutting tool having a central body with tapered faces, each face having a beveled edge; abrasive supporting shoes fitting upon said faces, means for holding the shoes in position on the body member and means for adjusting the position of the shoes in the'direction of the length of the tapered face-t0 adjust the diameter of the tool and for holding the shoes in adjusted position.

In testimony whereof I afiix my signature.

CLARENCE W. TYDEMAN.

Images