US3851552A

US3851552A - Slitting machine

Info

Publication number: US3851552A
Authority: US
Inventors: R English; R Benson
Original assignee: Armstrong Cork Co
Current assignee: Armstrong World Industries Inc
Priority date: 1972-06-29
Filing date: 1973-10-17
Publication date: 1974-12-03
Anticipated expiration: 1991-12-03

Abstract

The invention contemplates a tool for slitting a tubular work piece of substantially constant cross-section, particularly for work pieces of relatively large bore diameter. To this end, a forwardly cantilevered frame includes elongate shoes or rails for retaining and supporting the bore of the work piece, at angularly spaced locations. At one or more of these locations an elongate guide serves a cutter slide or shuttle, there being two such guides or shuttles for the situation in which a cylindrical tube is to be severed (or substantially severed) into semi-cylindrical halves. The coordinated reciprocating feed of the slides is so synchronized with actuation of the cutter elements carried thereby that the slitting cut is made only during one stroke, the return stroke, of the slide-actuating cycle. In one specifically described embodiment, two cutter elements, one on each of two diametrically opposed slides, are set to project for cut at different maximum radii, one being such as to cut at less than full work-piece thickness, the other being set for greater than work-piece thickness. For a flexibly sheathed work piece, the slitted work piece thus becomes two hingedly related, substantially alike, elongated halves of the original tubing.

Description

United States Patent [191 English et al.

[ Dec. 3, 1974 SLlTTING MACHINE [75] Inventors: Richard B. English, Coplay;

Rudolph T. Benson, Jr., Walnut Port, both of Pa.

[73] Assignee: Armstrong Cork Company,

Lancaster, Pa.

[22] Filed: Oct. 17, 1973 [21] App]. No.: 407,091

Related US. Application Data [63] Continuation-in-part of Ser. No. 267,464, June 29,

1972, abandoned.

Primary Examiner-A. R. .luhasz Assistant ExaminerW. D. Bray Attorney, Agent, or Firm-Sandoe, Hopgood and Calimafde V 5 7] ABSTRACT The invention contemplates a tool for slitting a tubular work piece of substantially constant cross-section, particularly for work pieces of relatively large bore diameter. To this end, a forwardly cantilevered frame includes elongate shoes or rails for retaining and supporting the bore of the work piece, at angularly spaced locations. At one or more of these locations an elongate guide serves a cutter slide or shuttle, there being two such guides or shuttles for the situation in which a cylindrical tube is to be severed (or substantially severed) into semi-cylindrical halves. The coordinated reciprocating feed of the slides is so synchronized with actuation of the cutter elements carried thereby that the slitting cut is made only during one stroke, the return stroke, of the slide-actuating cycle.

In one specifically described embodiment, two cutter elements, one on each of two diametrically opposed slides, are set to project for out at different maximum radii, one being such as to cut at less than full work-piece thickness, the other being set for greater than work-piece thickness. For a flexibly sheathed work piece, the slitted work piece thus becomes two hingedly related, substantially alike, elongated halves of the original tubing.

22 Claims, 11 Drawing Figures PAIENTE can 3mm SEE! 2B? 3 I SLITTING MACHINE This application is a continuation-in-part of our copending application, Ser. No. 267,464, filed June 29, I972, now abandoned.

This invention relates to apparatus for producing one or more generally radial slits in a tubular work piece, such as a cut-off length of continuously produced foamed tubing of the nature described in Snelling, et al., patent application Ser. No. 69,661, filed Sept. 4, 1970 (now US. Pat. No. 3,754,064), or such as a rotationally-cast length of similar, but larger-diameter, tubing of the nature described in Snelling, et al. patent application Ser. No. 228,130, filed Feb. 22, 1972, now US. Pat. No. 3,790,320.

Said patent applications describe in general terms products which are circumferentially and longitudinally continuous tubes of foamed plastic, such as urethane, the same having an inner lamination or lining (such as paper) and an outer lamination or envelope (such as paper, metallic foil laminated with paper, foil laminated with a tough flexible plastic such as polyethylene, etc.). Said products provide a highly effective heat-insulating jacket for pipe or conduit, and it must be longitudinally cut into substantially semicylindrical halves, for application to existing pipe or conduit. A prior technique of longitudinally sawing or slitting, using a single cutting element supported from outside the tubing, is less than satisfactory. Also, the slitting technique described in copending Andrews, et al. patent application Ser. No. 113,342, filed Feb. 8, 1971, now U.S. Pat. No. 3,715,941, serves well for a variety of work-piece sizes, but the apparatus therein described is less than satisfactory for the case of largediameter work-piece bores, as produced by the casting machine of said US. Pat. No. 3,790,320.

It is, accordingly, an object to provide an improved tool for slitting tubing of the character indicated.

' Another object is to provide such a machine producing superior slitting cuts in the hands of relatively unskilled operating personnel.

A further specific object is to provide such a machine wherein the radial cut of one slitting tool can be at a controlled radially outward extent, short of full thickness of the tubular work piece, while another slitting tool, concurrently operative at a different angular location, can sever the full thickness of the'work piece, all without loss'of stabilized reference to the bore of the work piece.

Another object is to sever a work-piece of the character indicated into segmental halves, and in a single working stroke, such that no tears or burrs are produced at the liner, such that offal is substantially zero, and such that an unsevered hinge of envelope material is left along one to the exclusion of the other of two opposed, radially outwardly operative, simultaneously performed slitting cuts.

It is a general object to achieve the foregoing at minimum cost, particularly for large-diameter work-pieces, while maintaining maximum reliability and adherence to relatively close product tolerances.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, a preferred embodiment of the invention:

FIG. 1 is a simplified perspective view of a machine of the invention, shown with a loaded work-piece of relatively large diameter, in readiness for a slitting operation;

FIG. 2 is an enlarged fragmentary perspective view of parts of the machine of FIG. 1;

FIG. 3 is a simplified view in elevation of upper and lower work-supporting elements of the machine;

FIG. 4 is an enlarged fragmentary sectional view, taken at 4-4 in FIG. 2;

FIG. 5 is an enlarged view in elevation, partly broken-away and in section to show a slide or shuttle element of the machine;

FIG. 6 is an enlarged fragmentary sectional view, taken at 6-6 in FIG. 3;

FIG. 7 is a fragmentary view in perspective to illustrate machine operation on a tubular work piece;

FIG. 8 is a simplified diagram schematically indicating coordinated functions in the machine;

FIG. 9 is an end view of a tubular work piece to illustrate operation of a modification of the machine of FIGS. 1 to 8;

FIG. 10 is a perspective view of the modified machine to produce the operation of FIG. 9; and

FIG. 11 is an enlarged view in elevation of a part of the machine of FIG. 10.

Briefly stated, the invention in its presently preferred form utilizes tool-holder or slide means which we term a shuttle, by reason of the fact that it is longitudinally reciprocated within the bore of the work piece, in a two-stroke cycle. Forwardly projecting cantilevered work-supporting shoes support the work-piece and establish guides for a plurality of such shuttles, each of which carries its own retractable cutting tool.,ln the first stroke, both tools are retracted to enable the shuttles to bring the cutting tools to the forward end of the work piece, whereupon the tools are radially outwardly projected. Both cuts are made on'the return stroke, leaving tools out of the way when loading the work piece onto the machine and when removing the precision-slitted product.

Referring first to FIGS. 1 to 3 of the drawings, the invention is shown in application to a generally horizon tal machine, comprising like forward and rear upright frame assemblies 10-11 of laterally spaced legs and rigid transverse members 12-13, drilled, as at 14, at particular spacings which will serve theintended variety of work-piece sizes. A central elongate stem 15, which may be of hollow rectangular section, is secured to both frame members 12-13 and constitutes the backbone of a forwardly projecting cantilevered end. A tubular work piece 16 is supported by and around the cantilevered end of stem 15.

FIG. 3 is devoted to a simplified showing of upper and lower shoes or rail members 17-18, at diametrically opposed locations above and below the cantiliv ered end of stem 15. Rails 17-18 are at all times parallel and are preferably spaced for light frictional interference fit to the bore of an applied work piece 16; rounded forward ends of rails 17-18, as at 19, facilitate placement of the work, and rear stops (as at 20) determine full entry of the supporting rails 17-18 into the work. At one of these stops, a limit switch, suggested at 21, is actuated by the work piece to provide an interlock function with automated elements to be described- For radial-adjustment purposes, appropriate to the bore diameter of the work piece, each of the rails 17-18 forms an element of a so-called four-bar linkage or parallelogram in which the stem 15 is the central member, common to both such linkages. Thus, two like sets of parallel links 22-23 connect forward and rear parts of rail 17 to the central stem 15, and two similar sets of links 24-25 connect forward and rear parts of the rail 18 to the stem 15. Radius arms 26-27 are pivotally connected to forward and rear parts of rail 17 and have plural spaced apertures to enable a range of rail radii for which they may be pinned to stem 15; similar arms 26-27' for rail 18 serve the same purpose, and bolts 28-28 serve to secure corresponding radius arms 26-26 and 27' in common, to stem 15.

A further pair of parallel rails or shoes is carried by stem 15 at diametrically opposed locations, between the locations of rails 17-18, and these further rails serve the added function of elongated guides for the slide or shuttle devices 30-31 which carry cutting elements 32-33 for performing the slitting operation. The details of these parts-and their guides will be later described, but it suffices at this point to identify like elongate parallel channel members 34-35 having forward and rear pads or mounting plates 36-37, by which they may be securely bolted to members 12-13, at the desired offset from stem 15. Channel members 34-35 extend the full length of the machine, being held by adjustable rod means 38 at correct spacing from stem 15 at the far cantilevered end, thus assuring fidelity of their parallel alignments. As shown, double-acting fluid-pressure actuators 39-40 are mounted within channels 34-35 at the rear or non-cantilevered end; the rods 41-42 of those actuators are connected to the respective tool slides 30-31. The actuators 39-40 operate in unison, being connected in parallel, as will appear from later discussion in connection with FIG. 8.

Best detail of slides 30-31 and their guides will appear in reference to FIGS. 4, and.6. FIGS. 4 and 6 represent-slightly different arrangements, applicable to larger work pieces (FIG. 4) and smaller work pieces (FIG. 6). InFIG. 4, the central stem will be recognized as being reinforced by stabilizing blocks 45 secured as by welds to opposite flanks of stem 15 at their regions of support on frame members 12-13. A plate 46 extends beneath the combined width of stem 15 and its two stabilizing blocks 45, at each of the forward and rear locations of support, on members 12-13. Tie bolts, as at 47, secure all connections of stem 15 to frame members l2-13. The guide channels 34 (35) and their mounting pads 36 are similarly secured, as at 48, to the frame.

As shown, each shuttle guide comprises a channel member 49 of essentially rectangular included interior section, and having divergent outward flanges 50-51 at the open limits. Angle members 52-53 are secured to flanges 50-51 and serve to partially close the open side of the channel member 49. At their outer ends, the channel members 52-53 are formed to substantially match the curvature of the bore of theworkpiece, such formations being indicated at 52'-53' and terminating short of full closure of the channel mouth, i.e., leaving a short span S for free accommodation of the projectand-retract cycle of the cutter knife 32. Slight inward bends (as at 54) avoid any chance of members 52-53 fouling the workpiece bore, as will be understood. A backing plate 55 may be welded along the full length of the base of channel 49 for reinforcement purposes; thus reinforced, channel 49 is secured (by means not shown) to the base of the primary structural channel 34. To avoid interference between members 50-53 and the frame elements 12-13, local cutouts are provided as necessary, as suggested at 56. The formations 52'-53 may thus be viewed as elements of the elongated rail or shoe structure for firm support and orientation of the work piece at its hole.

The slide or shuttle construction is perhaps best shown in FIG. 5 to comprise an elongated body of substantially constant external contour adapted for guided running clearance within the channel 49; an integral upper part 61 of the slide body is of lesser width, for running clearance between the parallel walls of angle members 52-53. The body 60-61 is centrally cored at 62 and grooved at 63 to accommodate a pivoted clamp or hub 64 for removably mounting the cutter blade 32. As shown, the clamp structure 64 comprises a base plate 65 with a central boss 66, whereby it may be supported on a transverse pin 67 journaled in the slide body, on opposite sides of the groove 63. A chordal groove or channel 68 is of width and depth to accurately locate the blade 32, and a cover plate 69 spans the groove 68 and blade 32 to clamp a selected placement thereof. As shown, the two bolts 70 complete the assembly to blade 32. Also, as shown, a lug 71 forming part of the blade-support assembly carries a stop at 72, adjustably locked by means of a nut 73, to determine the blade angle at which counterclockwise rotation of the blade is to be limited at a body abutment 74. Spring means 74 referenced to the slide body will be understood to constantly resiliently urge blade 32 to the stoplimited counterclockwise position shown. It is in this position that blade 32 is set to perform its slitting function, utilizing its sharpened edge 32' to enter the work piece in a traverse of slide 30, from left to right in the sense of FIG. 5. Once the full traverse from left to right has been completed and a new work piece inserted into the machine, the next forward stroke of actuator 39 will, via its rod 4l,-drive slide 30 from right to left. In

the course of this displacement, the dull side 32" of blade 32 will contact the work and be forced in the clockwise direction to a limiting position, in harmless trailing contactwith the bore of the work. The heavy phantom outline 77 suggests how far in the clockwise direction the blade 32 may be thus driven within the groove 63, for non-working forward traverse within the bore of the work piece.

As indicated above, the arrangement of FIG. 6 depicts the situation for a smaller size work piece than that contemplated by the description thus far. The principal difference is the omission of stabilizing member 45 at the location of securing the central stem 15 to the frame members 12-13. The guide system 49-52-53 is as already described for FIG. 4, so-that the same reference numerals are employed. The only difference is that, since the organization of FIG. 6 is to support a bore of smaller diameter, the inwardly bent ends 52'-53' of angle members 52-53 are contoured as appropriate for the smaller diameter. FIG. 6 also shows that these angle members 522-53 may be provided in bores appropriate to the particular work diameters to be served, removable fastening at 78 between overlapping flanges being the only necessary operation to make the change, beyond, of course, adjusting the offset mount of the primary channels 34-35 in holes 14, as may bevnecessary.

FIG. 6 serves further to illustrate detail of the articulated support of the upper and lower rails 17-18. For example, the links 22 of the upper four-bar linkage are shown provided in duplicate on opposite sides of a mounting block 79 on rail 15, being pinned thereto at 80. The rail 17 is seen as an elongated channel 81 spanning the links 22 and pinned thereto by means 82 passing through a spacer bushing 83. The radius bores 26-27 are fastened to channel 17 on the outer surface thereof. Finally, an arcuate shoe plate 84, appropriate to the work piece bore contour, is secured to the outer end of the channel 17.

FIG. 7 illustrates a product of the described slitting operation. Initially, the elongated tubular length 85 is as formed by the machine and process of either of said Snelling et al. patent applications, namely a laminated conduit wherein circumferentially and longitudinally continuous foamed urethane or the like 86 uniformly defines an insulating annulus between an inner paper or the like liner 87 and an outer paper or the like sheet 88, which may be foil-laminated with a residual unadhered elongated flap 89. The length 85 will be appropriate to the effective span supportable on the rail and shoe system 17-18-52-53, a standard and convenient length being 4 feet. The flap 89 is angularly positioned such that the more extended knife blade 32 will develop the slit 90, close to but angularly offset (to the extent a) from and within the flap and its point of bonded overlap to its other edge 89'; the effective free extent of flap 89 should exceed the extent a, being preferably in the order of 2 a. It will be understood that simple means such as a wire bail (not shown), or merely a creased downward fold relying upon gravity, may be utilized to hold flap 89 clear of member 32 during the cutting stroke thereof. The other blade 33 is set'(when extended), as by suitable adjustment of its means 72-73, to cut radially clear of marring contact with the outer layer 88, as suggested by the symbol A in FIG. 7, to identify the limited penetration of slit 90',by blade 33. In an illustrative embodiment wherein the conduit bore 87 is of about l2 inches diameter and the work piece wall thickness is l 1% inches, the adjustment means 72-73 applicable to the blade 33 is set to cut approximately l/l6 to 1/8 inch short of the outer diameter of the work piece.

FIG. 8 is a very simplified diagram to illustrate automatic operation of the invention for each two-stroke cycle. A pressure fluid supply 92, as of compressed air, is connected to the actuator cylinders 39-40 via a solenoid operated on-off valve 93, and via reversing distribution-valve means 94, having separate output connections 95-96 to the tail and head ends of cylindrs 39-40. Means 94 includes solenoid-positioned actuating arm 97, the same being actuated up (as shown) when solenoid 98 is actuated; a manually operated starting switch 99 carried at the forward end of the main stem will be operative (with hold-in means 102) to control the forward stroke of the shuttles as long as the interlocking limit switch 21 certifies that a work piece is correctly positioned in the machine. In this circumstance, pressure fluid is supplied via line 96 to the head ends of both actuators 39-40, and a forward full stroke results. The stroke terminates upon shuttle contact with a forward limiting switch 100 (see FIG. 1) which is operative upon solenoid 101 to reverse the fluid'connections to actuators 39-40 and therefore to cause shuttle scribed slitting operation on the return stroke.

FIGS. 9, 10 and 11 illustrate application of the invention to a slitting operation wherein (a) the individual slits are cut at other than diametrically opposite locations and (b) the plurality of cuts exceeds two. In FIG. 9, a foamed tubular conduit 185, with inner sheath 187 and outer sheath 188 is radially slitted at three angularly spaced locations A-B-C in one cycle of operation of the machine of FIG. 10. The cut at A is for the full radial thickness of conduit 185, being offset to the extent or from the location beyond which flap 189 is free. The cuts at B and C are each radially outward through the foamed body 186, to a limited extent short of severance, all as previously described at in connection with FIG. 7. Thus, the slitted product of FIG. 9 comprises three arcuate segments, having hinged articulation via unsevered outer-sheath material at locations B and C. It will be appreciated that for certain sizes and proportions of conduit 185, it is a matter of shipping convenience and/or of field-use convenience to provide for multiple articulation.

The three-slit machine of FIG. 10 will be recognized for its resemblance-to the two-slit machine of FIG. 1 and therefore some of the same reference numerals are employed, as appropriate. The primary difference is in the provision of two angularly spaced elongate channel members -135 spaced from each other by forward and rear strut members as at 136, each member 136 having a central pedestal 137 by which it may be bolted to channel member 35. The three channel members 34-135-135 may be at substantially equal angular spacing and will be understood to be equipped with individual shuttle slides, guides and cutting blades, inthe manner already described for each of the. channel members 34-35 of FIG. 1; in FIG. 10, these individual internal parts are not shown, but the closely .spaced work-piloting angle members 152-153 are identified for channel 135, and the corresponding members l52"-153' are identified for channelhl35'. Individual double-acting fluid-pressure actuating means '139 is frame-mounted with an actuating-rod connection 141 to the shuttle (not shown) which is guided within the alignment of members 135-152-153; similar actuating means l39, mounted to frame 10-11 with suitable offset from means 139, is operatively connected at 141' to the shuttle (not shown) which is guided within the alignment of members 135'-152-153. And it will be understood that all three actuators 39-139-139 are fluid-pressure connected in parallel, as shown for the parallel connection of the two fluid-pressure actuators of FIG. 8.

With the described structure of FIG. 10, operation is much the same as has already been described for FIGS.

1 to 8, it being understood that the cutting blade of the shuttle for each guide system 34-135-135 is adjusted to accomplish the respective full and partial cuts described at A-B-C in connection with FIG. 9. Thus, in"

applying the work piece 185 to the machine of FIG. 10, angle members 52-53-152-153-152'l53 provide stabilized piloting support of the work-piece bore. When the cycle of operation is initiated by operation of switch 99, shoes 17-18 are outwardly displaced for still-firmer workpiece engagement, and all three shuttles simultaneously proceed through their forward strokes; their respective cutting blades then spring outwardly, being preset to obtain full or partial cuts, and all cutting proceeds during the return stroke. The finished, severed and double-articulated conduit 185 is then readily removed, and the machine is ready to take another tubular work piece for the next cycle of operation.

FIG. 11 shows basic considerations involved in construction of the strut 136, complete with central bolting alignments at 138-138 for securing the channel members 135-135, and with a transverse bore 139 to accept the bolt for mounting to channel member 35. In all three-cut usage where the cuts are at substantially equal angular spacing, the angle B between slopes of end faces 140-140 is substantially 60 degrees, thus assuring l20 separation between cuts B and C. And of course the effective length dimension L and offset dimension D are so selected in relation to the mounting of member 35 as to correctly center a work piece 185 of particular bore radius. For other bore radii, it will be understood that dimensions L and D are selected as appropriate, using another strut 136. Thus, a set of struts 136, properly sized at L and D, will enable quick change for the operative parts of the machine, to accommodate different standardized work piece sizes. By the same token, for example, another set of struts 136, wherein the angle ais approximately 90, will enable the machine to be set up for four equally spaced cuts,

using 90 spaced channels 135-135 (with their shut-.

tles, cutters, and actuators) mounted to the frame channel 35, while mounting a similar but oppositely facing pair of channel members to more of the same struts '136 carried by channel member 34; thus equipped, and with only one of the cutters set for a full cut, the finished product will be understood to be a severed and triple-articulated, hinged assembly of four 90 I sectors. I

It will be seen that the described machines meet all stated objects and are easily adapted for the firm cantilevered support of work pieces of a considerable range of sizes. The bore of the work piece is always supported by a plurality of elongate work-positioning elements at angularly spaced locations about the axis of the supported work piece. Adjustment to different bore diameters is readily made in such manner that parallel rails and shoes are always available. The particular described stroke cycle wherein cutting is performed only on the return stroke has the safety advantage that cutting blades are never exposed to the operator during loading or unloading operations, because loading and unloading must necessarily be accomplished via the projected cantilevered end of the support system.

While the invention has been described in detail for the preferred forms shown, it will be understood that modifications may be made without departure from the invention.

What is claimed is:

l. A slitting machine, comprising frame means including bore-contacting means extending along and within the bore of an elongated tubular work piece for removably supporting the work piece with its axis fixedly oriented, said frame including an elongated guide within the bore of the supported work piece, a shuttle including means coacting with said guide within the bore of the work piece, reciprocable actuating means coacting between said frame means and said shuttle for imparting to said shuttle a two-stroke cycle of guided longitudinal traverse in the bore of the work piece, radially retractable and extensible cutting means carried by said shuttle, and means synchronizing the radial position of said cutting means with said cycle such that in one of said strokes said cutting means is in retracted position and in the other of said strokes said cutting means is in work-piece cutting position.

2. The machine of claim 1, in which said frame means includes elongated work-bore positioning elements at angularly placed locations about the axis of a workpiece supported thereby, said shuttle being guided between two of said work-bore supporting elements.

3. The machine of claim 2, in which said frame includes a fixed central elongated member and in which at least two of said work-bore positioning elements are diametrically opposed on opposite sides of said member and are adjustably positionable in offset relation thereto.

4. The machine of claim 1, in which said guide is an elongate channel oriented with its-mouth open in the radially outward direction, work-bore piloting means at the outer limits of said channel, said last-defined means retaining said shuttle in clearance relation with the work-bore supporting radius, and said cutting means being retractable and extensible via the open mouth of said channel. I

5. The machine of claim 4, in which said channel is one of two, at angularly spaced locations about the axis of a workpiece supported by said bore-contacting and piloting means, in which a second similar shuttle is guided in said second channel, and in which said synchronizing means isconnected for coordinated operation of both shuttles.

6. The machine of claim 1, in which said cutting means comprises a blade pivotally supported by said shuttle, stop means coacting between said shuttle and blade for limiting an outwardly projected blade position, and resilient means biasing said blade in the direction of stop-means coaction.

7. The machine of claim 6, in which said stop means includes a selectively adjustable element, whereby the limited projected extent of said blade may be selected.

8. The machine of claim 1, for operation on a tubular work piece of predetermined length, and wherein said guide is of effective length overlapping both limits of said predetermined length, said cutting meanscomprising a blade pivoted to said shuttle and resiliently outwardly urged to a fixed radially projected position, the main body of said blade trailing the point of pivotal. support in a first stroke wherein the blade is retained by the work bore in a retracted position, said first stroke driving the shuttle sufficiently beyond the work bore as to have the blade clear the end of the work bore, whereby the blade is automatically outwardly projected before the blade encounters the work piece on the return stroke.

9. The machine of claim 5, wherein said channels are at substantially diametrically opposed locations, and

means for selectively determining the diametrical spacing thereof. 7

10. The machine of claim 9, in which the cutting means of each shuttle is a pivoted blade, and stop means associated with the respective blades and shuttles and determining first and second different maximum projected limits for the respective blades, whereby for a work piece of outer radius intermediate said different limits, one blade will cut the full workpiece thickness while the other blade cuts short of full work-piece thickness.

11. A slitting machine, comprising frame means including projecting cantilevered means for removably supporting an elongated tubular work piece with its elongation axis fixedly oriented, said frame including a fixed central stem member extending substantially the cantilevered extent, a first pair of diametrically opposed elongate work-supporting shoes carried by said stem for work-bore supporting engagement, a second pair of diametrically opposed elongate worksupporting shoes carried by said stem for work-bore supporting engagement at locations angularly offset from the shoes of said first pair, two of said shoes in cluding elongated guide means, separate slides guided by each of said guide means, radially movable work cutting elements carried by said slides, and means synchronizing radial movement of said cutting elements with longitudinally guided movement of said slides.

12. The machine of claim 11, in which all said shoes are selectively radially positionable, for accommodation of selected different work-bore diameters.

13. The machine of claim 11, in which the shoes of one of said pairs are elongated members of like fourbar linkages in which said stem is a bar common to both four-bar linkages.

14. The machine of claim 11, in which said frame includes forward and rear floor-based supports, said stem being secured to both forward and rear supports and projecting integrally for the cantilevered extent.

15. The machine of claim 14, in which said stem is hollow, and slide-actuating control means including a manually operable member at the forward end of the cantilevered part of said stem.

16. The machine of claim 15, in which the slideactuating control determines a cycle of reciprocation of said slides, from rearwardly retracted position to forwardly projected position, and return, the synchronizing being such that said cutting elements are retracted during the forward stroke of said cycle and are radially outwardly projected during the return stroke of said cycle, whereby work-piece loading over and removal from the cantilevered end may be accomplished remote from said cutting elements.

17. A slitting machine, comprising frame means including projecting cantilevered means for removably supporting an elongated tubular work piece with its elongation axis fixedly oriented, said frame including a fixed central stem member extending substantially the cantilevered extent, a plurality of elongate worksupporting shoes carried by said stem for work-bore supporting engagement at angularly spaced locations about said stem member, each of a plurality of said shoes including elongated guide means, separate slides guided by each of said guide means, radially movable work-cutting elements carried by said slides, and means synchronizing radial movement of said cutting elements with longitudinally guided movement of said slides.

18. The machine of claim 17, in which two of the shoes-having said guide means are at diametrically opposed locations.

19. The machine of claim 17, in which the number of shoes having said guide means is greater than two.

20. The machine of claim 19, in which the shoes having said guide means are at substantially equal angularly spaced locations. 7

21. The machine of claim 17, in which the number of shoes having said guide means is three. a

22. The machine of claim 21, in which the shoes having said guide means are at substantially equally spaced locations.

UNITED- STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. q 51 5:52 "Dated December 3 12 g ln nt fl Richard B. English, et al.

It is certified that error appears in theabove-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 3, Line 15, "27'" should read 27-27' Col. 4, Line 33, "74'- shouldread 75 vCol. 5, Line 54, "cylindrs" should read cylinders Col. 7, Line 34, angle should read a ngle fi Signed and sealed 11th day of February 1975.

' 7 (SEAL) Attest:

I c. MARSHALL DANN v RUTH f MASON. i Commissioner of Patents Attestlng Offlcer v i and Trademarks I FORM powsouro'sig) I I v I uscoMm-ocsoa'ls-pss #1 U5, GOVERNMENT PRINTING pFFICE I9l 9 0-36-33!

Claims

1. A slitting machine, comprising frame means including borecontacting means extending along and within the bore of an elongated tubular work piece for removably supporting the work piece with its axis fixedly oriented, said frame including an elongated guide within the bore of the supported work piece, a shuttle including means coacting with said guide within the bore of the work piece, reciprocable actuating means coacting between said frame means and said shuttle for imparting to said shuttle a two-stroke cycle of guided longitudinal traverse in the bore of the work piece, radially retractable and extensible cutting means carried by said shuttle, and means synchronizing the radial position of said cutting means with said cycle such that in one of said strokes said cutting means is in retracted position and in the other of said strokes said cutting means is in work-piece cutting position.

4. The machine of claim 1, in which said guide is an elongate channel oriented with its mouth open in the radially outward direction, work-bore piloting means at the outer limits of said channel, said last-defined means retaining said shuttle in clearance relation with the work-bore supporting radius, and said cutting means being retractable and extensible via the open mouth of said channel.

5. The machine of claim 4, in which said channel is one of two, at angularly spaced locations about the axis of a workpiece supported by said bore-contacting and piloting means, in which a second similar shuttle is guided in said second channel, and in which said synchronizing means is connected for coordinated operation of both shuttles.

8. The machine of claim 1, for operation on a tubular work piece of predetermined length, and wherein said guide is of effective length overlapping both limits of said predetermined length, said cutting means comprising a blade pivoted to said shuttle and resiliently outwardly urged to a fixed radially projected position, the main body of said blade trailing the point of pivotal support in a first stroke wherein the blade is retained by the work bore in a retracted position, said first stroke driving the shuttle sufficiently beyond the work bore as to have the blade clear the end of the work bore, whereby the blade is automatically outwardly projected before the blade encounters the work piece on the return stroke.

9. The machine of claim 5, wherein said channels are at substantially diametrically opposed locations, and means for selectively determining the diametrical spacing thereof.

10. The machine of claim 9, in which the cutting means of each shuttle is a pivoted blade, and stop means associated with the respective blades and shuttles and determining first and second different maximum projected limits for the respective blades, whereby for a work piece of outer radius intermediate said different limits, one blade will cut the full work-piece thickness while the other blade cuts short of full work-piece thickness.

11. A slitting machine, comprising frame means including projecting cantilevered means for removably supporting an elongated tubular work piece with its elongation axis fixedly oriented, said frame including a fixed central stem member extending substantially the cantilevered extent, a first pair of diametrically opposed elongate work-supporting shoes carried by said stem for work-bore supporting engagement, a second pair of diametrically opposed elongate work-supporting shoes carried by said stem for work-bore supporting engagement at locations angularly offset from the shoes of said first pair, two of said shoes including elongated guide means, separate slides guided by each of said guide means, radially movable work cutting elements carried by said slides, and means synchronizing radial movement of said cutting elements with longitudinally guided movement of said slides.

13. The machine of claim 11, in which the shoes of one of said pairs are elongated members of like four-bar linkages in which said stem is a bar common to both four-bar linkages.

16. The machine of claim 15, in which the slide-actuating control determines a cycle of reciprocation of said slides, from rearwardly retracted position to forwardly projected position, and return, the synchronizing being such that said cutting elements are retracted during the forward stroke of said cycle and are radially outwardly projected during the return stroke of said cycle, whereby work-piece loading over and removal from the cantilevered end may be accomplished remote from said cutting elements.

17. A slitting machine, comprising frame means including projecting cantilevered means for removably supporting an elongated tubular work piece with its elongation axis fixedly oriented, said frame including a fixed central stem member extending substantially the cantilevered extent, a plurality of elongate work-supporting shoes carried by said stem for work-bore supporting engagement at angularly spaced locations about said stem member, each of a plurality of said shoes including elongated guide means, separate slides guided by each of said guide means, radially movable work-cutting elements carried by said slides, and means synchronizing radial movement of said cutting elements with longitudinally guided movement of said slides.

18. The machine of claim 17, in which two of the shoes having said guide means are at diametrically opposed locations.

20. The machine of claim 19, in which the shoes having said guide means are at substantially equal angularly spaced locations.

21. The machine of claim 17, in which the number of shoes having said guide means is three.