US1323278A - Barrel-reamer - Google Patents

Description

iUNITED STATES PATENT OFFICE.

FRANK 0. HOAGLANID, OF HART'FORD, CONNECTICUT, ASSIGNOR TO PRATT & WHITNEY COMPANY, OF NEW YORK, N. Y., A CORFORATION OF NEW J ERSEY. I

BAnREL-BEAMEB.

Application filed. June 8, 1917.

To all Iwhom z't may concern Be it known that I, FRANK O. HOAGLAND, a citizen ofthe United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Barrel- Reamers, of which the following is a specification.

The invention relates particularly to reamers adapted to be used in long or deep holes such as those in rifle barrels. Heretofore considerable difliculty has been encountered in doing work of this class. There has been a marked tendency for the reamers t`o grip or adhere to the sides of the bore and become broken, and'even when this did not happen there was difliculty in removing the chips from the several cutting edges which were provided. Furthermore, only a very small amount of 'metal could be removed at a single Operation, and when it was necessary to remove larger amounts of metal several successive operations were necessary.

The principal object of the invention 1s to provide an improved reamer suited for Operation in long or deep'holes and adapted to remove a relatively large amount of metal without encountering dfiiculties such as those above referred to. v

In the accompanying drawing I have shown several embodiments of the invention in order that the scope and application thereof may be clearly perceived. It will be understood, however, that the drawing is intended to be merely illustrative and is not intended to define or limit the scope of the invention, the accompanying claims being relied upon for that purpose.

Figure 1 is a side view of a reamerV embodyingthe invention.

Fig. 2 is a side view similar to Fig. 1 but showing a different embodiment of the invention. p

Fig. 3 is another view similar to Fig. 1 but showing a still different embodiment of the invention. e

Fig. 4: is an end view, on a greatly enlarged scale, of the reamer shown in Fig. 1,

the view being taken from the, left.

Fig. 5 is a transverse sectional view on the same scale as Fig. 4 showing an embodiment of the invention different from that shown in Fig. 4. This view can be understood as being taken along the line b-b of Fig. 1.

Specification of Letters Patent.

Patented Dec. 2, 1919.

Serial No. 173,439. i

The drawing shows reamers adapted for I reaming relatively small holes, but it is to be understood that the invention is not so limited and that with suitable modifications it is possible to construct larger reamers embodying the invention.

Referring first to Figs. 1 and 4: of theV drawing, A represents the main cutting section of the reamer. This section is tapered, increasing in diameter from the plane a-a: to the plane 6-22. The taper is greatly exaggerated in the drawing in order that it may clearly appear. In practice,vhowever, in a reamer such as is used for reaming rifle barrels, the taper may be between three and four one-hundredths of an inch. Adjacent the section A is a section B which prefwhich the reamer is provided.

In reamers as heretofore constructed, a great deal of difficulty has been encountered because of the tendency of the outer walls of the reamer to grip or adhere to the surface of the bore. I avoid all such difliculties by relieving the outer wall of the reamer in such a way that it contacts with the surface of the bore only at the cutting edge'2 and at a point 3d which is nearly opposite the cutting edge. Preferably, as shown in Fig. 4, the point 3 is located a little less than 180 from the cutting edge 2. The location of the point 3 a little less than 180 from the cutting edge 2 makes it possible for the reamer rto be firmly supported and guided by the wall of the bore. If the point of tangency 3 were exactly opposite the cutting edge there might be a tendency for a wedging action which would produce chattering and uneven cutting. .The wall of the reamer from the cutting edge 2 to the point 3 conforms to smooth curves which touch the wall of the bore at 2 and 3. The curves begin to deviate from the respective cutting circles immediately behind the cutting edge. By the cutting circles I mean the circles CJi which are followed by the several points along the cutting edge, these circles 'conforming, or approximately conforming, to the Outline of the bore. From the point 3 to the point 4 at the side of the notch opposite to the cut-ting edge the curves are continued and lie within the outline of the bore. It will be understood that the amount of relief is considerably exaggerated in Fig. et in order that it may be clearly seen. In practice, the amount of relief will ordinarily be but a few thousandths of an inch.

As concerns the broader features of my invention, I do not limit myself to any particular form of curve for the outer wall of the reamer, but I prefer to form the outer wall, at least between the points 2 and 3, in the form of spirals which are constructed about a center 5 eccentric of the center of the bore, designated by 6. The center 5 is located on the diameter which passes through the point 2 and is on the opposite side of the center 6. As illustrated in Fig. 4, the center 5 is so positioned that the spirals constructed about it have points of tangency with the cutting circles and with the Outline of the bore at 3. As shown in this figure, the spirals are continued beyond the point 3 and terminate at 4:.

It will be seen that when relative turning is effected in the direction of the arrow in Fig. i, the cutting edge 2 will be forced along the surface of the bore and the reamer will be held in central relationship to the bore by reason of the engagement between the wall of the reamer and the surface of the bore at 3. At all other points the wall of the reamer and the surface of the bore are out of engagement, thus making it impossible for the reamer to bind or adhere. Preferably, as shown in Fig. 1, the cutting edge 2 is notched at 2a so as to break up the chips which are removed.

Anyone of several constructions may be provided for controlling and driving the sections A and B of the reanier. As shown in Fig. l, the reamer is provided with a pilot or plug section C which has a diameter slightly greater than the smallest diameter of the section A. This pilot section C is very slightly smaller than the original diameter of the hole to be reained and assists in guiding the reanier and in holding it central. The pilot section C is connected with the section A through an intermediate neck section D of reduced diameter. Connected with the section C is a driving stem E by means of which the reamer is operated. For supplying oil to the groove 1 and to the cutting edge 2 there is provided a central oil hole 7 which extends through the stem E and the pilot C and intersects the groove 1 at 84. As illustrated, the groove l is closed atl one end adjacent the point of communi- Qatinn Wthrthe 01.1 hele, 7. In. 7practice the stem E is connected with a suitable tube or hollow rod, the connection usually being made by 'brazing The central aperture of the tube. registers with the .hole 7 and at the other end of the tube suitable means are provided for supplying oil under high pressure.

Relative rotative movement is elfected between the reamer and the device to be reamed, and in the case of a rifle barrel the roaming is usually effected by means of a machine which holds the barrel against rotative movement and which rotates the reamer relatively thereto. In Operation, therefore, it may be considered that the reamer is rotated. At the same time relative feeding movement is effected to oarry the reamer deeper into the bore. Usually the reamer is held against longitudinal movement and the barrel is fed. In the case of the construction shown in Fig. 1, the movement of the barrel is toward the right indicated, and the bore is enlarged to a diameter equal to that of the reamer att-J).

During Operation, oil under high pressure is supplied through the hole 7 and enters the groove l through the Opening at 8. The plug section C prevents the oil from fiowing back toward the left.

The oil which enter-s the groove l serves not only to lubricate the cutting edge and to provide a film of oil between the wall of the rcamer and the surface of the bore, but also serves to carry away the chips which. are removed by the cutting edge 2. This latter function of the oil is very important as it prcvents the reamer from becoming clogged. I/Vith earlier constructions having a plurality of cutting edges and a plurality of grooves, much diflicu ty was encountered because of the tendency for one or more of the grooves to become clogged, the oil flowing out through the remaining grooves. As soon as any one groove became even partially clogged the flow of oil through that groove was immediately lessened7 thus automatically increasing the clogging. rI`he result was that in earlier reamers all but one or two of the grooves were clogged very quickly after the cutting Operation started. lvith my improved reamer the oil must necessarily flow through the one groove which is provided, and any possible clogging is entirely prevented.

The form of the reamer shown in Fig. 1 is known as a. pullli` reamer, but my invention is equally Well adapted to be embodied in a push reamer. Such a reamer is shown in Fig. 2. This reamer comprises sections A' and B' which are similar respectively to the sections A and B of the reamer shown in Fig. l. A groove lI extends longitudinally of these sections but terminates a short distance from the left-hand end of the section B'. A cutting edge 2' is pro- :viden at one. side-of the groove 1' and thev sections A' and B' are relieved in the way already described. I prefer not to provide a pilot section such as is shown in Fig. 1. This is not needed to direct the oil and I find that without it the reamer will in many cases cut more accurately. A stem E' is connected with the left-hand end of the section B' and is provided with an oil hole 7' which communicates with the groove 1' This reamer operates in the same way as the reamer shown in F ig. 1 except that the relative feeding movement is in the opposite direction, the rifie barrel being fed toward the left as indicated. The chips are forced out of the groove l' in advance of the reamer instead of behind it.

In 3 I have shown a reamer adapted for hand use or for use in a turret lathe. This comprises sections A' and B' similar respectively to the sections A and B of the reamer shown in Fig. 2. This reamer is provided with a longitudinal groove 1' similar to the groove l, and at 2" there is provided a cutting edge similar to the cutting edge 2'. The sections A and B" are relieved in the way already described. Connected with the left-hand end of the section B" is a shank E by means of which the reamer may be rotated oiheld against rotation as required. It Will be obvious that means may be added for snpplying oil if needed.

Under some circumstances it may be desirable to provide a form of relief slightly different from that already described and shown in Fig. This is illustrated in Fig. 5, which inay be considered to be a cross section taken along the line b-b of Fig. 1. The form of relief differs from that shown in Fig. f-l in that the wall of the reamer from the point 3 to the point 4 conforms to circular arcs constructed about the center 5. It will be noted that because of the eccentricity of the center 5 the circular arcs between 3 and et lie within the outline of the bore. This construction is preferable in some cases as it provides a smaller clearance between the wall of the reamer near the point 4; and the adjacent part of'the surface of the bore. Itwill be understood that between the points 2 and 3 there will be a film of oil extending from the point 2 to the point 3, and that there Will be a similar film of oil extending from the point 3 to the point 4:. In some cases, when the construction shown in Fig. -l is used, the Opening between the point 4 and the wall of the bore will be too great to be filled by an oil film. In such cases I prefer to provide the construction shown in Fig. 5 in order to reduce the width of this Opening.

What I claim is:

1. A reamer having a single cutting` edge .and a relieved outer wall extending backward in smooth curves from the cutting edge to points of tangency to the cutting circles nearly opposite the cutting edge.

2. A reamer having a single cutting edge and a relieved outer wall extending backward in smooth curves from the cutting edge to points of tangency to the cutting circles a little less than 180 from the cutting edge.

3. A reamer having a single cutting edge and a smoothly curved outer wall which touches the cutting circles at the cutting edge and which is tangent to the said circles at points nearly opposite the cutting edge and which is elsewhere relieved.

4. A reamer having a single cutting edge and an outer wall conforming to spirals constructed about a center eccentric of the cutting circles and extending from the cutting edge at least to points nearly opposite thereto, the said outerv wall having points of tangency with the cutting circles.

5. A reamer having a single cutting edge and a relieved outer wall eXtending back- Ward in spiral curves from the cutting edge to points of tangency to the cutting circles nearly opposite the cutting edge.

6. A reamer having a single cutting edge and an outer wall partly conforming to spirals constructed about a center eccentric of the cutting circles and partly conforming to circular arcs constructed about the said eccentric center.

7. A reamer comprisi'ng a single piece of metal approximately circular in general transverse sectional Outline and having a sector of approximately 90 removed to provide a single cutting edge, the outer wall being relieved to provide points of intersection With the cutting circles at the cutting edge and at points of tangency to the cutting circles nearly opposite the cutting edge.

8. A reamer approximately circular in general transverse sectional outline and having a: longitudinal sectoral groove which provides a single cuttingedge and a central longitudinal oil hole at one end which communicates with the sectoral groove, the reamer being provided at the last said end with a plug section which prevents the escape of oil at that end.

In testimony whereof I hereto aflix my signature.

FRANK O. HOAGLAND.

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