US3855886A - Conduit-slitting method - Google Patents

Abstract

The invention contemplates a method and apparatus for longitudinally slicing tubular workpieces into separate parts which, for the case of cylindrical tubing, conveniently become semi-cylindrical halves. In specific application to flexibly sheathed, foamed-plastic tubing, the slicing action is complete at one local longitudinal alignment along the workpiece wall; but at the diametrically opposite local longitudinal alignment, the slicing action is radially outward to an extent short of severing the sheath, so that the sheath may hingedly connect the otherwise severed semi-cylindrical halves. As disclosed, the invention is applicable to continuous operation on successive lengths of tubing, in a conveyor-fed environment.

Description

I States atem 1 1 1111 3,855,886

Andrews Dec. 24, 1974 CONDUlT-SLITTING METHOD 3,745,621 7/1973 Andrews 83/9 x [75] Inventor: 326M101? E. Andrews, Kutztown, Primary Examiner Donald R. Schran 7 Attorney, Agent, or Firm-Sandoe, Hopgood and [73] Assignee: Armstrong Cork Company, Calimafde Lancaster, Pa. 22 Filed: June 22,1973 [57] ABSTRACT The invention contemplates a method and apparatus [21-] App! N for longitudinally slicing tubular workpieces into sepa- Rela'ted US. Application Dat rate parts which, for the case of cylindrical tubing, 62 7 f5 N '282,653,, 12 1972 P L N conveniently become semi-cylindrical halves. In spe- 2 7; 1; er 0 Hg 3 O cific application to flexibly sheathed, foamed-plastic tubing, the slicing action is complete at one local lon- 52 us. c1 83/7, 83/9, 83/54 giwdinel alignment along the workpiece well; but at 51 Int. Cl. B26d 1/02 the diametrically pp leeel longitudinal align- [58] Field of Search 83/1, 54, 7, 8, 9, 10, meet, the Slicing eerie is radially Outward to an 83/180, 29/235 tent short of severing the sheath, so that the sheath I may hingedly connect the otherwise severed semi- 5 R f n Cited cylindrical halves. As disclosed, the invention is appli- UNITED STATES PATENTS cable to continuous operation on successive lengths of tubing, in a conveyor-fed environment. 3,577,889 5/1971v Er1ksen.....,.. 1 83/54 X 3,715,941 6 Claims, 8 Drawing Figures 2/1973 Andrews 83/7 CONDUIT-SLITTING METHOD This application is a division of my copending application Ser. No. 282,653, filed August 22, I972 now U.S. Pat. No. 3,799,012.

The invention relates to a method and apparatus for the mass-production longitudinal slicing of a succession of tubular. workpieces, such as flexibly sheathed foamed-plastic tubing produced by techniques described in Snelling U.S. Pat. No. 3,1 18,800, issued Jan. 21, 1964. v

In the slicing of tubing of the character indicated, it has been the practice to individually chuck each workpiece for exposure to slicing tools which are reciprocated in both advance and return strokes over the full length of the workpiece, before the workpiece can be removed to enable a recycling. While the resulting product is of acceptable quality, the costs of individual workpiece handling and of multiple strokes become significant economic factors.

It is, accordingly, an object of the invention to provide an improved method and apparatus of the character indicated, wherein the indicated factors are eliminated or substantially reduced.

Another object is to meet the above object with continuous unidirectionally operative process.

A further object is to provide such a machine wherein a continuous succession of workpieces may be automatically sliced.

Still another object is to provide such a machine which is selectively adaptable to performing functionally similar slicing operations on a variety of workpiece sizes.

A still further object is to provide such a machine wherein workpiece length is not a limiting factor.

' A general object is to achieve the above objects with basically simple structure which will produce at large volume and with sustained accuracy.

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 form of the invention:

FIGS. 1, 2 and 3 are simplified end views of a workpiece, to illustrate a succession of steps performed by the invention;

FIG. 4 is a front perspective view of the working part of a machine of the invention, set for operation on a workpiece of relatively large-diameter;

FIG. 5 is a rear perspective view of the machine shown operating on a smaller-diameter tubular workpiece W;

FIG. 6 is a simplified view in elevation of the entire machine;

FIG. 7 is an enlarged fragmentary view in elevation of tool-supporting structure of the machine; and

FIG. 8 is an enlarged fragmentary view, taken at the section line 8-8 of FIG. 6.

FIGS. 1, 2 and 3 serve to identify the structure of an illustrative tubular workpiece and the successive operations performed thereon, in accordance with the invention. The workpiece, as formed by techniques of said Snelling patent, is a given cut-off length, for example, a four-foot length, of cured foamed urethane or the like plastic 10, constituting the primary insulating body or bulk, between an inner paper sheath 11 and an outer sheath 12, preferably cloth-reinforced, for flexibility and durability. The outer sheath 12 may be a laminated composite of metal foil, paper, and the reinforcement cloth. Both sheaths 11-12 are bonded to the foamedplastic body 10, the outer sheath 12 continuously enveloping the same from an inner starting point 13 to an outer limit 14 of bonded overlap; beyond location 14 the outer sheath 12 comprises an unbonded flap 15 extending at least the circumferential distance Sbeyond an unbonded location 16 at which a slicing operation is to be performed. I

FIG. 2 illustrates that initially the flap 15 is folded back on the adjacent bonded region of sheath 12 so as to expose the radial alignment 16 for slicing, without harm to the flap 15. FIG. 2 also serves to illustrate that a first slicing step in the inventive method involves a radial cut 17, from the inside and radially outward, to a location which is just short of the outer sheath 12. As will later be more'clear, this cut is performed by a radially oriented knife blade, held by an elongate stem and tool holder, extending longitudinally in the bore of the workpiece. The cut' 17 is thus through the inner sheath and through virtually the entire body-wall thickness of the foamed material 12, it being noted that .at the longitudinal location atwhich cut 17 is made, the remaining circumferential extent of the body 10 and both sheaths 1l12 remains intact, thus retaining body-shape and position control while the slice, 17 is being made.

FIG. 3 illustrates the subsequent step of performing a second radial slice, at a location longitudinally removed from'that at which slice 17 is made, and, therefore, at a time subsequent to that of forming slice 17.

Slice 18 is preferably in the same axial plane as slice 17, I

being at location 16 and; therefore, slightly offset from the bent-back flap 15. The resulting product comprises like semicylindrical halves A-B, hingedly connected by flexible sheath material at C, and equipped with a free flap 15 by which the alignment 16 of adjacent body faces (at slice 18) may be overlapped after the product has been applied to a pipe of outside diameter to fit the bore of the product. j

'In FIGS. 4, 5 and 6, the machine of=the invention is seen to comprise an elongate generally horizontal guide frame 20 extending between spaced floor-mounted pedestals 21-22 each of which carries pulley means 23-24 for the guidance and support of the upper stretch 5? an endless conveyor loop 25. Theloop 25 may be a sprocket chain, belt-driven from a motor M to the shaft of pulley means 24. The direction of drive is such as to unidirectionally progress the upper stretch of the conveyor loop 25 in the left-to right direction, in the sense of FIG.- 6, as shown by arrows. In FIGS. 4 and 5, each link of the conveyor loop is seen to include a flat laterally extending plate 26, having laterally outward projecting ends which derive .support from opposed flanges 27 of the guide means 20- which forms part of the machine frame. The connected adjacent link elements of the conveyor are of lesser lateral extent and are guided by and between the spaced adjacent edges of flanges 27. The conveyor 25 is completed by provision of work-engaging lug members 28'at spacings exceeding the anticipated unit-length of the workpieces; as shown in FIG. 4, a lug member 28 may be the formed-up edge of one of the plates 26, with a'wideslotted central region, to avoid interference with a slicing tool.

Aside from the upper longitudinal stretch of the conveyor 25, the work-positioning means of the machine comprises stabilizing elements or rails 30-31 which extend parallel to each other and to the guide'means '20 throughout a work-stabilizing region, between upright girder frames 32-33 at spaced central locations along means 20. Each girder frame comprises two upright channels 34-35, secured by spacers 36 to frame 20, at equal wide lateral offsets on opposite sides of the central vertical plane of symmetry of the guide means 20. A flanged girder 37 unites the upper ends of the channels 34-35, and the open dimensions within the girderframe enclosures 32-33 are selected to'amply accommodate the largest-diameter workpiece anticipated for the machine. Threaded rods 39, brazed to rails 30-31 at appropriate spacing, are lock-nutted to selected apertures in channels 34-35, each channel bottom being. drilled with a series of vertically spaced apertures, whereby the elevation of rails 30-31 may be adjustably selected, as appropriate for the diameter of workpieces to be sliced. Further rail-positioning adjustment is afforded by the lock-nutted clamping of rods 39 to channels 34-35, to the end that rails 30-31 in the region 32-33 shall be spaced substantially by the diametral extent of the workpiece; preferably, this region 32-33 extends longitudinally to an extent substantially exceeding the largest diameter of workpiece handled by the machine. As shown'in the foreground of FIG. 4, the rails 30-31 diverge at the mouth or work entrance, being positioned by adjustable jack means 40 atan appropriate aperture elevation on spaced further uprights 41.

For larger-diameter workpieces, i.e., the situation depicted in FIG. 4, a central longitudinally extending flange girder 42 is bolted to the centers of the upper girders of both frames 32-33, thus rigidly uniting these frames and providing greatest work clearance within the frames. For smaller-diameter workpieces, an intermediate bar or girder member-43 is secured to both channels 34-35 of each frame 33-33, at an intermedior rails 30-31,the frames 32-33 serve the additional function of supporting the tool-positioning means, the

- tools being shown as first and second knife-blade eleble of slicing bodyand both sheaths 11-12 at location 16, to define the upper slice 18.

The other tool holder means, i.e., for tool 45,.comprises a radial strut portion 48, adjustably secured to support member 42, and a longitudinally extending stem portion 49 whereby a holder 50 for tool 45 may be positioned in longitudinally forwardly offset relation, i.e., forwardly of the mounted longitudinal location of tool 44. Preferably, the extent of such longitudinally forward offset, of the lower tool 45 with respect to the upper tool 44, is at least in the order of the workpiece bore diameter. As shown, the stem portion 49 comprises two steel straps, with width dimensions vertical, and oriented face to face, so as to clamp the toolholder plate 50at the forward end and to clamp the strut 48 at the rear location. Generally, the set-up of the tool-positioning elements places the stem portion 49 at the center of the workpiece, with ample clearance to the workpiece bore,-and so as to enable blade 45 to make the restricted work entry described at 17 in connection with FIG. 2.

FIG.- '7 provides further detail of construction for strut 48, which is seen to comprise a flat plate, having raked leading and trailing edges 52-53 which are tapered for non-fouling passage through the slit (18) path 1 developed by the upper tool 44. Preferably, theforments 44-45, both of which have sharp cutting edges support element of the tool-positioning means. To this end, first tool-holder means 46 serves-the upper blade 44, said means 46 being formed-in or secured to the forward end of member 42. The set-up elevation of support member 42 should be such that the tool 44 which is thereby positioned will define a slicing plane at location 16 (see FIG. 1), i.e., such that the cutting edge of blade 44 is in the central vertical plane of symmetry'of the guide means 20; at the same time, the elevation is so selected that blade 44 will intercept only the adjacent upper wall thickness of the workpiece, spanning the inner and outer radii and, therefore, capaward longitudinal offset of tool 44 ahead of strut 48 is at least in the order of the diameter of the workpiece, as appears from the proportions in FIG. 6. Radial adjustment of strut 48 is afforded by two sets of drilled mounting apertures 54-55, both passing through the maximum strut-body thickness. The rear apertures 55 serve a pivot function, for connection the the support member 42 so that a vertical jack-screw 56 in a bracket 57 carried at an upper forward part of the strut body' I will fully secure the adjusted tool 45) elevation set-- ting- In use, and assuming correct stabilizer adjustment and tool-holder positioning for the intended workpiece size, successive workpieces W are applied to conveyor 25 at the load region L (FIG. 6), forward of each succeeding feed lug 28, and angularlyoriented to place the alignment 16 in slightly offset relation to the adjacent fold of flap 1-5. The flared mouth of rails 30-31 quickly establishes a stabilized central orientation of the workpiece and retains the same for its full passage through the slicing region, and if desired, one or more longitudinally spaced spring finger elements, as at 58, may vbe secured to member 42 to assure light residual downward loading pressure on the workpiece throughout the slicing operation.

The lower tool 45, being forward of the upper tool, first establishes the precision limited-entry cut, '17, while circumferential integrity is retained at the longitudinal location of this first tool cut. Thereafter, the upper tool 44 fully slices the upper and diametrically opposite tubewall, at 18, as already described. Finally, the finished product is retrievable at a downstream location R, or it may simply be projected off the end of the conveyor loop 25, as it rounds the drive pulley means 24.

' It will be seen that the described machine and method meet all stated objects. In practice, the product adheres to close tolerance requirements, as to depth of the cut 17 and as to alignment of the upper slice 18. Adjustment for a changeover of workpiece size is readily accomplished with simple mechanics tools.

While the invention has been described in detail for the preferred form shown, it will be understood that modifications can be made without departure from the scope of the invention.

What is claimed is:

l. The method of longitudinally dividing a flexibly sheathed tubular workpiece into hinged semicylindrical halves, which comprises first radially outwardly slicing the workpiece wall on a longitudinal alignment locally proximate to the desired hinge axis and to a radial extent short of severing the sheath, and thereafter radially slicing a diametrically opposite locale of the entire workpiece wall on a longitudinal alignment parallel to said first alignment, whereby at the local region of first slicing action the local integrity of the remaining circumferential extent of the workpiece body provides a stabilizing action to assist in accurate control of said radial extent, so that hinge action cannot be available until a point in time after completion of the entire firstand second-slicing action is at least in the order of the bore size of the workpiece.

3. The method of claim 1, in which the steps of firstslicing action and second-slicing action are performed simultaneously on the workpiece and in longitudinally offset relation along the workpiece.

4. The method of longitudinally dividing a flexibly sheathed tubular workpiece to form hinged arcuate cylindrical segments, which comprises'first radially outwardly slicing the workpiece wall on a longitudinal alignment locally proximate to the desired hinge axis and to a radial extent short of severing the sheath, and thereafter radially slicing an angularly offset locale of the entire workpiece wall on a longitudinal alignment parallel to said first alignment, whereby at the local region of first slicing action the local integrity of the remaining circumferential extent of the workpiece body provides a stabilizing action to assist in accurate control of said radial extent, so that hinge action cannot be available until a point in time after completion of the entire first-slicing action. I

5. The method of claim 4, in which each of said slicing steps is performed in a longitudinal traverse of the workpiece.

6. The method of claim 4, in which both said slicing steps are performed in the same longitudinal traverse of the workpiece, the first-slicing action being longitudinally forward of said second-slicing action in said traverse.

Claims (6)

1. The method of longitudinally dividing a flexibly sheathed tubular workpiece into hinged semicylindrical halves, which comprises first radially outwardly slicing the workpiece wall on a longitudinal alignment locally proximate to the desired hinge axis and to a radial extent short of severing the sheath, and thereafter radially slicing a diametrically opposite locale of the entire workpiece wall on a longitudinal alignment parallel to said first alignment, whereby at the local region of first slicing aCtion the local integrity of the remaining circumferential extent of the workpiece body provides a stabilizing action to assist in accurate control of said radial extent, so that hinge action cannot be available until a point in time after completion of the entire first-slicing action.

2. The method of claim 1, in which the longitudinal offset between the performance of first-slicing action and second-slicing action is at least in the order of the bore size of the workpiece.

3. The method of claim 1, in which the steps of first-slicing action and second-slicing action are performed simultaneously on the workpiece and in longitudinally offset relation along the workpiece.

4. The method of longitudinally dividing a flexibly sheathed tubular workpiece to form hinged arcuate cylindrical segments, which comprises first radially outwardly slicing the workpiece wall on a longitudinal alignment locally proximate to the desired hinge axis and to a radial extent short of severing the sheath, and thereafter radially slicing an angularly offset locale of the entire workpiece wall on a longitudinal alignment parallel to said first alignment, whereby at the local region of first slicing action the local integrity of the remaining circumferential extent of the workpiece body provides a stabilizing action to assist in accurate control of said radial extent, so that hinge action cannot be available until a point in time after completion of the entire first-slicing action.

5. The method of claim 4, in which each of said slicing steps is performed in a longitudinal traverse of the workpiece.

6. The method of claim 4, in which both said slicing steps are performed in the same longitudinal traverse of the workpiece, the first-slicing action being longitudinally forward of said second-slicing action in said traverse.

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