US1910118A

US1910118A - Self centering rifling head

Info

Publication number: US1910118A
Application number: US281156A
Authority: US
Inventors: George W Mccune
Original assignee: Individual
Current assignee: Individual
Priority date: 1928-05-28
Filing date: 1928-05-28
Publication date: 1933-05-23
Anticipated expiration: 1950-05-23

Description

May 23, 1933.

G. W. MCCUNE SELF GENTERING RIFLING HEAD Filed May 28. 192s Z2 Hd 2 Sheets-Sheet l Patented May 23, 1933 UNITED s'mras lAir'salia ortica GEORGE w. MccUNE, or BRIDGEPQRT, CONNECTICUT, AssIeNoa or ONE-HALF rro yJOHN A. CORNELL, orvisainei'iroar, coNNEcricnT f' SELF CENTERING RFLING HEAD .Application filed May 28, 1928. Serial/No. 281,156.

This invention relates to a riflinghead and has for an object to provide an improved head of this character which will automati cally adjust itself to variations in the diameter of the bore of the gun and will automatically maintain the centerof the head in the center of the bore, so that the ritling will be uniform throughout the full length lof the bore and will also be uniform through out the circumference of the bore.

It is also an object of the invention to provide a rifling head with which all the rifiing grooves may be cut simultaneously throughout the entire periphery of the bore.

It is another object .of the invention to provide an improved means for adjusting the cutters to secure a greaterrange of adjustment, and in which the cutters will be simultaneously adjusted.

llith the foregoing and other objects in view, the invention consists in certain novel features of construction, combinations and arrangements of parts as willbe more fully described in connection with the accompanyA ing drawings. In these drawings,

Fig. 1 is a longitudinal section through the hea v Fig. 2 isan end elevation looking from` the left of Fig. 1 with the enclosing housing removed and a portion of the front plate broken away to more clearly show the construction. Y

Fig. 3 is a transverse section substantially on line 3-3 of Fig. 1.

Fig; 4 is a partial side elevation looking toward the left of Fig. 2. v

Fig. 5 is a detailelevation of a portion of the front plate of Fig. 2 showing the cut` ters extended in cutting posit-ion. L

Fig. G is a front 'elevation with the front head or plate removed showing how the device is arranged for riliing a relatively small bore.

the cutter'adjusting means, and Y Fig. 8 is a perspective view of one-half of the adjusting means of Fig. 7. i In rilling guns, particularly large guns, it is very diflicult to cut the grooves uni- Fig. 7 is a partial front view similar ,to Fig. showing a modified construction offormly due tok changes in temperature lof the gun and also thev riiling tools. Also any variation in the size of the bore will cause ununiformrifling. The common practice is to provide a brass cylindrical block on the rifling head carrying the cutting tools which is supposed to fit the boreof the gun, but

gun due to the increase of temperature or other variation will permit the head to drop so that its axis is below the center line of the bore, and therefore, the rifling grooves will not be cut of a uniform depth. To overcome this -objection l have produced a construction of head which will automaticallyvadjust itself to Variations in the diameter of the bore and will thus automatically center itself so as to maintain'its axis always on thecenter line of the bore, and thus will cut, the rifling grooves uniformly throughout the length of the bore and also throughout the periphery thereof. l have also probored, and which carries the rifling head.,

This head as shown, comprises a cylindrical central threaded into the end of the bar 10 and also into a ring or head 12 vwhich is securedto the flange 13 of the bar 10 by meansof a plurality of screws 1li. Mounted on the cylindrical portion of the member 11 is an adjusting member 15 which is preferably a continuous member and has a cylindrical bore fitting the member 11 and on which it is .slidable longitudinally. This adjusting member 15 has one or more conical surfaces in the lpresent construction two of them 16 and 17, which form cam surfaces for adjusting the

intermediate members

18 and 19 respectively. These interf mediate members are shown as segmental members 1n four parts, in other words there or Vbody member 11 which isYV v it will be apparent that an expansion of the are four segments on each of the

conical surfaces

16 and 17 although aV greater or less number may be used if found preferable. The

inclined cam surfaces

16 and 17 may be continuous conical surfaces but it is preferred to provide inclined flats 20 thereon cooperating with similarly inclined flats 21 on the segmental members, as this arrangement is less likely to bind than would be a continuous conical surface.v The

elements

18 and 19 are enclosed byA a resilient cylindrical shell or casing 22 which is slit at one side and overlapped to prevent entrance of chips, as shown at 23, so that it may expand or contract. Its tendency, however, is to expand and fit the Vsurface of the boref The body memb-er 11 has a flange 24 at its inner end, and the members18 and 19 are Aheld against longitudinal movement by this flange andthe head or ring 12. V

Resilient means is providedwhich tend to shift the adjusting member 15 longitudinally of the kmember 11 to force the

cam surfaces

16 and 17 against the

members

18 and 19 andthus tend to force them outwardly against thev casing 22, andrtherefore, expand this casing. This resilient means in the construction shown comprises a plurality of coiled springs 25 seated at their opposite ends in sockets in the opposed ends of the members 12 and 15. VAny suitable number of these springs may be employed, preferably equally spaced around the member 15. Their outer ends may rest against plates 26 engaging adjusting screws 27 vby means of which the tension of the springs may be adjusted Means is provided for limiting the ex# andinO movement of the casing 22. At P e r its outer end a ring 28 isthreaded on the flange 13 and has a reduced lateral extension 29 engaging the end of the'V casing 22. This reduced extension is threaded, as

shown at 30, for a sizing nut or ring 31 which has a beveled inner end 32 cooperating with a similar bevel formed on the end of the casing 22. These rings are provided with sockets 33 to receive spanner wrenches for operating these rings. At the opposite end the casing 22 has a similar and opposite bevel 34 cooperating with a similar-bevel on a plate or ring 35 secured to the flange 24 of the member 11 byany suitable means, such as screws 36. It will be Aapparent that by adjusting nut 28 the casing 22 will be forced toward or allowed to recede from the ring35, and then the nut orring 31 may be adjusted against the bevel ofthe casing 22 to prevent thisV end expanding a greater amount than theY opposite end against the ring 35, thus maintaining the casing thesame size throughout,and these beveled surfacespreve-nt the casing 22 expanding beyond a certain maxi-V mum limit. The casing 22 is made to a greater diameter than that of the bore of the gun, say about three-sixteenths of an inch. Then a longitudinal strip is cut out of it at one side and'it is then compressed, ground and lapped to size.

The cutting tools for cutting the spiral grooves ofthe rifle are carried'at the forward or inner end of this head. The plate 35 is provided. withla plurality of radial clove-tailed slots 37 in which are mounted carriers 38 forK the cutters 39, and these carriers have dove-tailed ribs 40 on their back walls sliding in the dove-tailed grooves 37 so that these carriers are guided for radial movement in the ring 35. lThe cutters 39 may each have one or more 'cutting edges for cutting the rifling grooves.` In theforin shown in Fig. 2 each cutter has three cutting edges 41 so that each cutter will cut three grooves.V ln the form shown in Fig. 6 each cutter has only two cutting edges, but it will be vunderstood that they may each vhave one or more cutting edges as is found desirable. The body of the carrier is recessed as' indicated at 42, to receive the cutters 39, and thecutters maybe secured thereto by any suitable means, such as-screws 43 and properly located by dowel pins 44.

Mounted on the inner end of the member 11 is a guiding stud 45, and'it may be mounted in the member 11 by threading it into the same, as indicated at 46. This stud 45 provides a support and guide for adjusting block 47 which is fmounted to slide longitudinally in the member 45. This block is provided with an inclined peripheral groove providinginclined or conical surfaces 48 and 49 which are parallelto eachother and bear on the opposite sides of an extension 50`on each of the carriers 38, and this extension has inclined walls on its opposite sides corresponding to the inclination of the walls 48 and 49.v It will be apparent from this construction that ifthe block 47 is forced to the right, as viewed in- Fig. 1, the carriers 38 and the cutters 39 will be forced laterally outwardly by coaction of the 'inclined surface 49 with those of the extensions 50, while if the block 47 is forced to the left, as viewed in Fig. 1, the inclined surface 48 will have a camming action on the other side of .the extensions 50 and will draw the carriers 38 and the cutters 39 radially inwardly, and therfore, the positions-of the cuttingedges 41l of all the cutters may be simultaneously adjusted and for equal` amounts by shifting camming surfaces 48 and V49 together with the cooperating surfaces on the extensions in Fig. l, and these cutters would be drawn v inwardly by shifting block 47 to the right.

Clamped against the outer surface of the ring 35 is a plate or guiding head 52 which is threaded onto the end of the stud 45, as shown at 53, and by which it may, thereforeybe clamped against the surface of theA ring 35. The outside diameter of this plate or head is approximately the diameter of the bore to be rified and serves as a guiding means to guide the head into the bore when the head is inserted in the bore to start the rifling operation, and thus protects the cutters 39 and properly positions them Vrelative to the bore of the gun for the beginning of the riding operation' The outer rim of the member 52 may be provided with ribs 54 to cooperate with a suitable tool for properly screwing this head onto the head or unscrewing it` therefrom, and clamping it againstv the ring'35.

The means for adjusting the block 47 may take different forms but that shown in the drawing is a very effective one. In this 'arrangement as shown the plate 52 has an eX- tension or support 55 carrying an adjusting screv. 56 which is supported at its opposite end in the body of the member 52 and has threaded engagement with a nut 57 which is held against rotation by a pin-58. The nut 57 has a notch 59 inlits outer edge cooperating with a holding pawl 60 `pivotally mounted on a sliding pin 6l connected to the block 47 and a spring 62 normally tends to hold the pawl 60 in the notch in the nut 57. The adjusting screw 56 may be provided with a suitable calibrated gauge 63 to indicate the amount of adjustment. The bloclz'47 may be shifted manuallyto contract or collapse the cutters 39 by means of a rod 64 connected to the block and slidable in the head 52. This rod has a connecting .39 their radial movementsand alsoto prevent entrance of chipsinto the adjusting' mechanism. The inner wallv of the head`52 is recessed and carries an annular clamping member 69 which is guided for lateral movements on a cylindrical shoulder 70. The

- ring 69 is held against turning movements by a key: Iliandfit is' threaded on its outerr wall, as shown at .72, for threaded vengagement with an adjusting4 ring 73 which fills the space between the head 52, the cutters 39 l r and the front face of the ring 35. This ring 7 3 has socketsl 74 for insertion of a spanner wrench or other suitable too-lfor rotating this ring.k By turning this lring-the clamp'- ingring 69 isA adjusted to give the proper.

pressure on'the cutters 39 to assist in holdingl them in proper position land prevent their chattering but it should be sufficiently loose when shifting the block `47 to ypermit the cutters 39 to be' moved radially under the action of the adjusting block 47. After adjustment the ring 69vv maybe tightly clamped against the-cuttersf39 tohold them prevent' 'chattering in proper position and during the cutting stroke.

The operation is as follows: As indicated the head or plat'e52f will `guide the 'device into the bore of the gun and prevent injury to the cutters or the gun by positioning` the head central in the bore. After the pawl 6()` is seated in the nut 57 the adjusting screw 56 is turned to bring the cutters 39 in proper position for the first cut and thon the head I is forced through the gun'in the usualmenner to cutthe riiing grooves, and it will'be apparentthat suilicient cutters maybe carried` by thishead to simultaneously Vout all of the grooves. 'At the end lof the inward movementy of the head the pawl 60 may be releasedy fromthe nut 57 and then the op erator by manipulating the lever 'may shift the block 47 to lthe left as viewed in Fig. l, which will cause. the inclined wallsv 48 coacting with the extensions 50 oni the cutter carriers 38 to draw the cutters inwardly to the full' line position of Fig. 1,.; so that the head may be withdrawn from the bore for the 'next operation. lAfter the head is drawn back tothe inlet end, the lever 65 is manipulatedto force the block 47 to the right which will force the cutters out-l wardly. The p'awl 60vis again seated in the notch 59 in the nut 57 to hold the bloclr147 and therefore, the cutters 39 in proper position. The adjusting screw 56 may be rotated to force the block 47,inwardly or to the right as viewedzinFig. l, to force the cutters outwardly the proper amount for the next step which may be accurately' determined by the this bore dueto changes in temperature'or other reasons. This is accomplishedl

bythe members

15, 18, l9and 22and cooperating elements.v Thesprings 25 tend to force the adjusting member 15 to ther left, as shown lO ranged about the member 11 and are pressed against the inner surfaceof the resilient split casing 22. They, therefore,-expand this casing so that itsl outer surface always fits the surface ofthe bore of the gun. The out-k lU ward or expanding movement, however, is

limited by the beveled surfaces 32 land 34 at the opposite ends of this casing, and as indicated above this maximum expansion may be adjusted for the maximum bore of the 219 gun by manipulation of the wing nuts' 28 and 31. As the head moves through the bore of the gun the casing 22 is held snugly against the surface of the bore, as indicated by the action of the springs 25.

cause of contraction of thegun walls by reduction in temperature the surface ofthe bore will press the casing 22 inwardly to correspond with the size of the bore and 39 against the action of the spring 25, but during the expansion and contraction of the casing 22 the center of the head will always correspond with the center of the bore due to the peculiar arrangement of the elements,

35 Tand therefore, the head is always automatically centered in the bore and the rifiing cutters 39 are all uniformly and pro erly positioned.throughout the periphery o the head, and the rifling grooves are all cut to a Z4O'uniform depth throughout their entire length.

The head as shown in Fig. l, is for a relatively large gun. Fig. 6 shows how the same principal may be used for iiiling a 4,5 relatively small gun. In this arrangement each carrier 38 supports a cutter 75 having only two cutting edges 41, or the cutter may have only one cutting edge as desired, and as the sides 76 of this cutter may be "arranged` parallel to each other and radially of the head I am enabled to secure maxi mum adjustment.

In Figs. 7 and 8, I have shown an adjusting block 77 to take the place of the block 5547, Fig. 1, of somewhat different construction. This block, however, is lnot as desirable as the block 47 because it is more ex pensive to make and does' not permit as great'a range of adjustment asY the block 47 It is a conical block provided with'T-shaped slots 78 in its outer inclined surfacejin 'which similar T-shaped extensions 79.1on carriers` corresponding to the carriers 48 for the cutters are guided. g Thus as the block 77 is 65 shifted the same as the block 47 these Should a a5 4portion ofthe bore be somewhat smallerbe- 1., In aY rifiing head, a cylindrical bodyv member,a continuous member having a cylindrical bore mountedV to slide longitudinally on the body-member, a plurality of segments, outside the continuous member, co acting cam surfaces on the continuousmember and said segments, resilient means tending to shift thevcontinuous member to shift the segments outwardly,and a split casing embracing the segments adapted to lit the bore of a gun and held in engagement therewith by said segments.

2. In arifling head, a cylindrical body member, an adjusting member having a bore to fit the body member and slidable longitudinally thereon, a plurality of segments j outside the adjusting member, cooperating cam surfaces on the adjusting member and the segments, asplit resilient casing embracing the segments, and one or more springs tending to shift the adjusting member to expand said casing to fit the bore of a gun and center the head therein.

3. Ina rifling head, a Vcylindrical guiding member, an adjusting member having a cylindrical bore to lit that of the guiding member and slidable longitudinally thereon, said adjusting member being provided with cam surfaces inclined to the axis of the head, a plurality of laterally movable members engaging said cam surfaces, one or more springs tending to shift the adjusting member to move the .laterally movable members outwardly, a split resilient cylindrical casing enclosing said laterally movable members radapted to iit the bore'of a gun and held in engagement therewith by said members, and lcutters carried by sai head.

4. In a riiiing head, a cylindrical guiding member, an adjusting member having a cylin drical bore to fit that ofthe guiding member and slidable longitudinally thereon, said adjusting member beingv provided with cam surfaces inclined to the axis of the bead, a plurality ofy laterally movable members engaging said cam surfaces, one or more springs tending to shift the adjusting member to force the laterally movable members outwardly, a split resilient cylindrical casing enclosing said laterally'movable mem bers and adjusted thereby to lit the bore of a gun, and adjustable means for limiting the expansion of said casing.

5.1Ina rifling head, a cylindrical guidy ing member, an adjusting member having a Vcylindrical bore to fit that of the guiding member and slidable longitudinally thereon,

ber to force the laterally movable members outwardly, a split resilient cylindrical casing enclosing said laterally movable members and adjusted thereby to fit the bore of a gun, adjustable means for limiting the expansion of said casing, a plurality of cutters carried by said head, and means for si-A multaneously adjusting said cutters.

6. In a rifling head, an expansible cylindrical casing to fit the bore of the gun, an adjusting member movable longitudinally of the head and having cam surfaces inclined to the axis of the head, a plurality of segments enclosed by the casing and located between said casing and the adjusting member, said segments being capable of radial movement under action or said cam surfaces, resilient means tending to shift the adjusting member to force said segments outwardly to expand the casing, means to maintain said adjusting member concentric with the axis of the head, and a plurality of cutters carried by the head.

7. In a rifling head, an expansible cylindrical casing tofit the bore of the gun, an adjusting member movable longitudinally of the head and having cam surfaces inclined to the axis of the head, a plurality of radially movable members between the adjusting member and the casing and arranged to be shifted by the action of said cam surfaces, resilient means tending to shift the adjusting member to expand the casing, adjustable means to limit the expansion of the casing, a plurality of cutters carried by the head, and means for simultaneously adjusting the cutters radially of the head.

8. In a riling head, means for guiding the head in the bore of a gun, a plurality of radially movable cutter supports carried by said head, an adjusting block movable longitudinally of the head, cooperating means on the block and the supports to shift the supports by movement of the block, an adjusting screw, a nut operated by said screw, a detachable connection between the nut'and the block to hold the block in a given position depending on the position of the nut, and independent means for shifting the block to shift the cutter supports when said connection is disconnected.

9. In a rifling head, means for guiding the head in the bore of a gun, radial guides, cutter supports in said guides, riiing cutters carried by said supports, a head forwardly of said cutters, a clamping ring mounted for sliding movement on said head and adapted to engage and guide the cutters, and an adjusting ring closing the space between the head and the cutters and having threaded engagement with vthe clamping ring to adjust the same toward and from the cutters in' a1 direction laxially of the head to :clamp the cutters in adjusted positions and torelease them.

10. In a rilling head, means movable withy the head for automatically maintaining the' axis ofthe head in the center of the bore regardless of changes in the sizes of the bore, comprising a split resilient casing free to expand and contract and tending to expand so as to lit the bore regardless of changes Yin the diameter thereof, and self acting means enclosed by said casing free to expand and contract with the casing, means for mounting said latter means so that it is always coaxially with the head for automatically maintaining the casing coaxial with the axis of the head, and rifling cutters carried by said head.

ll. In a rifling head, a split resilient casing free to expand and contract to fit the bore of the gun and movable with the head,

an adjusting means enclosed by said casing adapted to expand the casing, resilient means tending to shift the adjusting meansv to expand the casing and automatically maintain it the size of the bore,'means concentric with the axisof the khead for mounting said adjusting means, and a series of gutters for riliing grooves carried by said ead. V

l2. In a head for rifling the bore of a gun, a split resilient casing adapted to expand and contract so as to fit the bore of the gun in spite of variations in the size of, this bore Vand movable with the head, resilient means tending to expand the casing to automatically maintain it the size of the gun bore, a plurality ofl cutters for simultaneously cutting a pluralityk of rifling grooves in the bore carried by said head, and means for simultaneously adjusting the cutters radially of the head.

13. In a head for rifling the bore of a gun, a split resilient casing movable with the head and adapted to expand and con-k tract so as to at all timesl fit thebore of the gun, an adjusting means enclosed by said casing, resilient means tending to shift the adjusting means to expand the casing and automatically maintain it the same size as the gun bore, means to maintain the casing always concentric with the axis of thev head, a plurality ofcutters carried by the head adapted to simultaneously cut a plurality of rifling grooves in the bore, and means simultaneously adjusting the cutters radially of the head.

14. In a head for rifling the bore of a gun, a resilient split casing movable with the head and adapted to expand and contract so as to at all times lit the bore of the gun, rey silient means tending to expand .the casing to automatically maintain it the same size as the bore, adjustable; means to engage the casing to limit the expansion of the casing, L plurality of cutters Carried by the .head adapted to simultaneously cut a plurality of fillingY grooves in the bore, and lueunsffor` simultaneously adjusting said cutterslrvadially of the head.

Irl-testimony whereof I ax my signature.

` GEORGE W. MCCUNE.