US2747440A - Reamer - Google Patents

Description

May 29, 1956 C. s. KYSER 2,747,440

REAMER Filed Feb. 5, 1953 ATTOR N EYS United StatesV Patent O REAMER Chauncey S. Kyser, Mason, Mich., assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February s, 195s, serial No. 335,241

s claims. (cl. 7'7-ss) The present invention relates to reaming means and more particularly to means for reaming the interior surface of gun barrels and other tubular members requiring precision nishing ofthe interior surface.

In order to provide the interior of a tubular member such as a gun barrel with a surface having a finish of the required quality, it is necessary to employ a reamer of this type in the rough and nish stages of the machining process. ln the past it has been extremely di'icult to perform this operation with the required degree of accuracy particularly in bores having a large length to diameter ratio. As the machining operation proceeds longitudinally of the bore, the reamer may become out of axial alignment which will result in a curved bore. In order to maintain axial alignment, numerous attempts have been made to devise a satisfactory reamer which employs an i elongated pack These packs are rigidly secured to the shank of the reamer so as to rotate therewith. Due to the length of the pack, the reamer will be maintained in alignment. To allow the pack to t tightly in the bore but still rotate, they are generally made of wood, Babbitt metal or some other -suitable bearing material. Although this has tended to increase the accuracy of the reamer, such packs are heavy and produce a great deal of friction. The friction not only results in excessive wearing of the pack but also in generating excessive amounts of heat during the reaming operation. As a result of the rapid wearing, the pack quickly becomes a loose iit in the bore and has to be replaced. Reamers have been devised which employ resilient means for maintaining the pack in tight contact with the barrel. However, these packs have a discontinuous surface and therefore suffer from having a limited amount of the pack in contact with the surface of the bore. Moreover, the resilient construction allows chatter to develop during the teaming operation which results in a non-circular bore.

it is therefore proposed to provide a reamer having a substantially continuous cylindrical pack which is adapted to resiliently engage the machined surface of the bore at all times. The reamer employs a pair of rigid members, each of which has a resilient member bonded to the exterior thereof. The resilient members are shaped to form a substantially continuous cylindrical surface which is compressed in the bore of a gun barrel to thereby maintain the reamer in accurate alignment at all times.

In the drawings:

Figure l is a side elevational view of a reamer embodying the present invention, a portion thereof being broken away.

Figure 2 is a cross-sectional view taken substantially along the plane of line 2-2 of Figure l.

Referring to the drawings in more detail, a reamer 10 which is adapted to ream the bore of a gun barrel includes a frame 12 fabricated from metal or any other suitable material. A pack 14 embracing the present invention is rigidly mounted on the frame 12. 'Ihe pack 14 is positioned between tool holding means 16 on one end of the frame 12 and a tank 18 on the other end.

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The frame 12 has a cylindrical collar 20 intermediate the ends thereof. The tank 18 is positioned adjacent the collar 20 and projects outwardly to be locked in a rotating member suitable for driving the reamer 10. The frame 12 has a shank 22 that is disposed on the opposite side of the collar 29 from the tank 18. Although the shank 22 may be of any desired shape, the present embodiment employs a shank having at sides 24 that form a substantially rectangular cross-Section. The tool holding means 16 for retaining a set of bits 26 in position include a pair of diagonally disposed passages 28. The passages 28 are adjacent the outer end of the shank 22 and have set screws or other retaining means which permit easy removal or adjustment of the bits 26. The outer ends of the bits 26 are provided with cutting edges suitable for reaming or otherwise machining the interior surface of a tubular member such as a gun barrel.

The pack 14 which is secured to the frame 12 includes a pair of rigid members 3) and a pair of resilient members 34. Each of the rigid members 30 have a base 38 with a pair of parallel arms 40 positioned substantially normal to the base 38. The rigid members 30 may be secured to the frame 12 so as to embrace approximately one half of the shank 22. Thus when both of the members 36 are in position, they form a box-like structure which completely encloses the shank 22. lt is desirable that the rigid members 36 be small enough to be a squeeze tit on the shank 22. lf the bases 38 and arms 40 of the rigid members 3G bear directly against the flat sides 24, the rigid members 3% will be reinforced by the shank 22 and the pack 14 will maintain its desired shape at all times.

The pair of resilient members 34, which may be fabricated from an elastic material that is resiliently compressible, is bonded to the exterior of the rigid members 30 by any suitable means such as vulcanizing. Since the exterior of the pack 14 formed by the resilient members 34 must be in sliding contact with the surface of the bore, the elastomer employed must create a minimum amount of sliding friction and be capable of immersion in lubricating fluids. The elastomer 2-chloro-l,3 butadiene, commercially available under the trade name of neoprene, has been found to be well adapted for this use. lt is preferable when molding and bonding the resilient members 34 onto the rigid members Sti to make the resilient members 34 larger than required and then grind them to the desired size. To secure the pack 14 to the frame 12, a plurality of bolts 42 are countersunk into the resilient members 34 and threadably engage the shank 22. The bolts 42 are countersunk by means of openings 44 that extend completely through the resilient members 34. This allows the heads of the bolts 42 to act directly on the rigid members 3i? and draw the rigid members 30 tightly onto the shank 22. A smali mechanical clearance 45 may be provided between the arms 40 of the rigid members 30 and the ends of the resilient members 34 to eliminate any interference when the bases 33 engage the sides 24 of the shank 22. lt should be noted that by beveling the corners 4S of the shank 22 and the rigid members 30, the thiclmess of the resilient members 34 may be increased in the vicinity of the corners 4S. It will be observed that the exterior of the resilient members 34 form a substantially continuous or unbroken cylindrical surface 52 which can not be distorted into an out-of-round shape as it slidably engages the surface of the bore.

The life of the reamer 10 may be greatly increased and the operation thereof made considerably easier by means of lubrication. To insure an adequate delivery of lubricants to the surface of the resilient members 34, a lubricating passage 54 may be provided in one or more of the members. In the present instance this passage 54 comprises a helical groove or channel 56 that is recessed in the cylindrical surface 52. It will be observed that Agun tube.

.bersloiI and the gun barrel atall times.

y To'utilize the lreamer 1(l, t hev rigid members 33, with the resilientmembers 34 Vbonded thereto, are secured to V.the shank122'of the frame 12 and the bits 26 are adjusted to provide the desired cutting action. The resilient members 34'are then ground or otherwise formed to the desired shape. `It is'desirable that the normal or Vuncompressed diameter of the -pack 14 ybe greaterthan 'the diameter, of the cutting 'circle ofthe bits 26. Thus when'the pack 14 is in the` bore, the resilientmembers 34 l .will be compressed to act like a solid. This will maintain the reamer in alignment at all times, but it will not interfere with1the operation ofy the reamer. The reamer 10 and gun barrel are then placed in a lathe or other machinevsuitable for supplying the Vpower for rotating the The reamer is then started in one end of the bore as the tube rotates. As the tube rotates, the

reamer is advanced through the bore thus machining the Y interior surface 0f the bore.

While but one embodiment has been illustrated and Y described, it will be apparent to anyone skilledin the art that ,the invention maybe embodied in numerous other specic 4forms than that described without departing from lthe spirit thereof. it is, therefore, desired that the pres- -ent embodiment be considered in all respectsillustrative and lnot restrictive, reference beinghad'to the appended claims'rather than to the foregoing description :to determine the scope of the invention.

vWhat is claimed is:

1. Tube reaming means comprising a frame vadapted to engage 'arotating drive member, 'a shank on said frame v'having Vone yend thereof adapted to support tool means, said shank'having planular surfaces thereon, a pairv of "rigid members having parallel arms thereon adapted to 4 f embrace said shank and engage said planular surfaces, :a semi-cylindrical resilient member bonded to each of said 'rigid members, theexterior of Vsaidresilient'members being shaped to form a substantially unbroken cylindrical surface when said rigid members are secured to said shank, vsaid cylindrical surface being adapted to rotate with said tool means. s Y

2. Tube reaming means comprising a frame member adapted to engage a rotating drive member, a shank on said frame having one end vthereof adapted to support tool means and having rplanular surfaces thereon, a pair of rigid members having parallel arms thereon adapted to embrace said shank and engage said planular surfaces,

Ya semi-cylindrical resilient member Vbonded to each of said rigid members, sai d resilient'rnembers'having countersunk openings therethrough communicating with said rigid members, and bolt means engaging said rigid members and being disposed in said countersunk openings to secure said rigid members on said shank and the exterior of said resilient members forming afsubstantially unbroken cylindrical surface when said rigid members are secured to said'shank. Y Tube rearning means comprising a frame ,member adapted to engage a rotatingdrive member, Va shank on s aidfraine having I one end thereof adapted to support toolmeans, a'pair of rigidmembers having arms thereon adapted to Vembrace said'shanln a pair of semi-cylindrical resilient members having the' ends thereof. disposed adjacent said tool/means, each' of said resilient'members being bondedto one of said'rigid members, bolt means countersunk in said resilient ymembers tosecure said rigid members t o said'shanlc'for rotation With said `tool means, the

exteriorof said resilient members forming a substantially L 0I1tiau0i1s Cyliadiaafaa Whns'aid rigid members reseauradto Said Shankifanda @recessed arbore Pasitionedpn said cylindricalsurface tofonm a helical passage extending axiallyalong said cylindrical surface.

References ici'fgd in'thefaie orfthis patear

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