US20050210947A1 - Method and system for forming a recess in a tubular workpiece - Google Patents
Method and system for forming a recess in a tubular workpiece Download PDFInfo
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- US20050210947A1 US20050210947A1 US11/071,888 US7188805A US2005210947A1 US 20050210947 A1 US20050210947 A1 US 20050210947A1 US 7188805 A US7188805 A US 7188805A US 2005210947 A1 US2005210947 A1 US 2005210947A1
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- workpiece
- rolling rollers
- recess
- pipe
- aperture
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D17/00—Forming single grooves in sheet metal or tubular or hollow articles
- B21D17/04—Forming single grooves in sheet metal or tubular or hollow articles by rolling
Definitions
- the present invention relates to a method and a system for forming a recess in a tubular workpiece like a pipe.
- Modern compartment seats of vehicles are equipped with headrests to protect passengers' heads upon collision. Headrests are typically attached to seat backs via stays, and users can adjust them in height by pulling them up or pushing them down.
- a typical mechanism for adjustment of the headrest's height includes hooks anchored in a seat back, and a series of locking grooves formed along each headrest stay.
- locking grooves can be formed by locally cutting their walls with a cutter on a milling machine.
- grooves in thin-wall pipes, having walls thinner than the required depth of locking grooves cannot be formed by cutting. Therefore, a different method is required to form grooves that indent from outer circumferential surfaces of thin-wall pipes to define sharp engagement surfaces having angled edges at their outer ends to maintain reliable engagement with hooks.
- JP-H08-90126 proposes a method of forming locking grooves of a headrest stay of a support rod of a handbrake by inserting a core member inside a pipe and depressing the outer circumferential surface of the pipe with a punch.
- Japanese Patent Laid-open Publication No. JP-2000-197922 proposes a method of forming a recess in a hollow shift fork shaft of a manual transmission for receiving a check ball by suing a press machine under the presence of a core member inserted into the hollow shaft.
- This publication also proposes a method of removing the core member from the shaft after forming the recess by rotating the core member having a unique configuration.
- Japanese Patent Laid-open Publication No. JP-2002-137673 is directed to a method of forming locking grooves at opposed positions of two longer parallel segments of a headrest stay made of a channel-shaped pipe having the two longer segments connected by one shorter segment.
- This publication proposes to form locking grooves by thrusting the pipe between a pair of roll punches located face to face under the presence of support rolls set aside the roll punches to support them.
- Japanese Patent Laid-open Publication No. JP-2002-210519 proposes a method of forming locking grooves of a headrest stay through two manufacturing steps, i.e. a preliminary shaping step and a final shaping step.
- this method forms a recess indenting from the circumferential surface of a pipe by driving a rotating punch down onto the exposed circumferential surface of the pipe while supporting the pipe in an arcuate groove of a holder.
- this method forms the locking groove by moving a press punch along a guide groove while covering the full circumference of the pipe with a holder cover having the guide groove extending along the recess.
- JP-2003-9991 proposes a method of forming locking grooves of a headrest stay by thrusting a punch having an end surface of a unique configuration onto a pipe.
- JP-2003-71522 proposes a method of forming locking grooves of a headrest stay by thrusting a press tool having a unique configuration onto the circumferential surface of a pipe while driving the tool transversally of the lengthwise direction of the pipe under the presence of a core member inserted in the pipe.
- Such a recess can be formed in a tubular workpiece having a thin wall and a high tensile force such as a thin-wall, highly tensile pipe.
- a recess having a sharp engagement surface having an angled edge can be formed on a tubular workpiece having a thin wall such as a thin-wall pipe in a single step.
- such a recess can be formed in a straight tubular workpiece like a straight pipe before it is bent to a channel-shaped member, for example, such as a headrest stay.
- a method of forming a recess in a tubular workpiece comprising:
- a workpiece holder having an aperture is preferably used to support the workpiece and expose a portion of the workpiece to be processed for forming the recess.
- the recess defines a sharp engagement surface having an angled edge
- at least a portion of the contour of the aperture adjacent to the engagement surface of the recess in the workpiece preferably makes substantially no gap from the contour of the final-stage rolling roller.
- a system for forming a recess in a tubular workpiece comprising:
- the workpiece holder may be divided in the moving direction of the roller support block. In case the roll support block moves vertically, the workpiece holder is divided to upper and lower portions, and one of the divisional portions may be moved to grip or release the workpiece inserted between them.
- FIG. 1 is a diagram for explaining the basic concept of the present invention
- FIG. 2 is a cross-sectional view of a locking groove formed to indent from the outer surface of a pipe typically used as a headrest stay;
- FIG. 3 is a cross-sectional view of another locking groove formed to indent from the outer surface of a pipe typically used as a headrest stay;
- FIG. 4 is a cross-sectional view taken along the IV-IV line of FIG. 3 :
- FIG. 5 is a diagram for explaining the outer circumferential configuration of rolling rollers used to form the locking groove shown in FIG. 3 ;
- FIG. 6 is a diagram for explaining a modification in positions of the rolling rollers
- FIG. 7 is a perspective view of a pipe holder that is a component of a test system
- FIG. 8 is a perspective view of a roller support block that is a component of the test system
- FIG. 9 is a diagram showing how the rolling rollers locally depress a pipe
- FIG. 10 is a diagram showing the contour of an aperture through which the rolling rollers can locally depress the pipe
- FIG. 11 is a schematic plan view of a common roller support block preferably employed in a mass production type system
- FIG. 12 is a schematic front elevation of the common roller support block preferably employed in the mass production type system
- FIG. 13 is a schematic diagram of a modified system having rolling rollers held stationary to form recesses in moving pipes;
- FIG. 14 is a diagram for explaining the outline of a mass production type system remodeled from a press.
- FIG. 15 is an upper diagonal view of a guide member having a guide hole and a pipe holder, which are located side by side.
- FIG. 1 shows the basic concept of the invention for forming a recess in a tubular workpiece typically of a metal.
- the recess-forming system shown in FIG. 1 is used to form locking grooves of a headrest stay.
- the headrest stay is a channel-shaped or M-shaped member made by bending a straight pipe to two longer pipe segments and one shorter pipe portion connecting the longer pipe segment, as already known in the art.
- the longer pipe segments have a plurality of locking grooves formed in intervals in their axial directions.
- the illustrated headrest stay has a first locking groove 3 (approximately 1.5 mm deep) having a channel-shaped cross section as shown in FIG. 2 , and a second locking groove 4 (approximately 1.5 mm deep) defined by a vertical plane and an opposed tapered plane as shown in FIGS. 3 and 4 .
- the recess-forming system 1 can be used to form these first and second locking grooves 3 , 4 .
- the recess-forming system 1 can be used to form locking grooves in a pipe bent to the shape of a headrest stay from a straight pipe as existing techniques do. Moreover, the recess-forming system 1 can form locking grooves in a straight pipe before being bent to the form of a headrest stay. That is, locking grooves 3 , 4 can be formed in a straight pipe of a predetermined length by the recess-forming system 1 , and the straight pipe may be bent later to manufacture a channel-shaped or M-shaped headrest stay.
- the straight pipes already having locking grooves, can be bent later so as to bring the grooves 3 , 4 at locations required for the individual types of headrest stays.
- various types of headrest stays can be manufactured.
- the recess-forming system 1 includes a pipe holder 5 for holding a pipe stationary, and a roller support block 10 that supports a plurality of rolling rollers (rolling dies for form rolling) 6 ⁇ 9 .
- the pipe holder 5 includes a fixing block 11 and a main holder block 12 that can tightly hold a pipe between them to prevent the pipe 2 from displacement in its lengthwise direction and rotation about the axial line.
- the pipe holder 5 has a guide hole 13 formed to extend in the vertical direction at a position adjacent the pipe 2 .
- the rolling rollers 6 ⁇ 9 are supported by the roller support block 10 to align in intervals along the axial line of the guide hole 13 , and supported for free rotation on the roller support block 10 by individual shafts 15 ⁇ 18 .
- the roller support block 10 is inserted into the guide hole 13 from above to work out a desired recess, i.e. the locking groove 3 or 4 , in the pipe 2 during a single reciprocal movement, preferably first down and next up, in the guide hole 13 .
- the rolling rollers are individually named the first-stage rolling roller 6 , second-stage rolling roller 7 , third-stage rolling roller 8 , and fourth-stage rolling roller 9 from the one first entering into the guide hole 13 to the one finally entering same as shown in FIG. 1 .
- the first-stage rolling rollers to the fourth-stage (final-stage) rolling rollers 6 ⁇ 9 are often called the first rolling rollers to the fourth-stage (final-stage) rolling rollers 6 ⁇ 9 hereafter.
- the support shafts 15 ⁇ 18 of the first to fourth rolling rollers 6 ⁇ 9 lie on a common vertical line L parallel to the direction of relative movement between the rolling rollers 6 ⁇ 9 and the pipe 2 , and diameters D of the first to fourth rolling rollers 6 ⁇ 9 gradually increase from the first rolling roller 6 .
- diameter D 1 of the first rolling roller 6 nearest to the guide hole 13 is smaller than the diameter D 2 of the second rolling roller 7 upwardly next to the first rolling roller 6 .
- the diameter D 2 of the second rolling roller 7 is smaller than the diameter D 3 of the third rolling roller 8 .
- the diameter D 3 of the third rolling roller 8 is smaller than the diameter D 4 of the fourth rolling roller 9 .
- D 1 ⁇ D 2 ⁇ D 3 ⁇ D 4 is the relation of D 1 ⁇ D 2 ⁇ D 3 ⁇ D 4 .
- Outer circumferential surfaces of the first to fourth rolling rollers 6 ⁇ 9 have outer circumferential surfaces (hereinafter often called shaping surfaces as well) corresponding to the shape of the first locking groove 3 ( FIG. 2 ) or the second locking groove 4 ( FIGS. 3 and 4 ).
- FIG. 5 shows the shaping surface of the fourth rolling roller 9 (solid line) together with shaping surfaces of the first to third rolling rollers 6 ⁇ 8 (broken lines).
- a groove (second groove 4 of FIG. 3 in the illustrated example) first depressed shallow by the first rolling roller 6 is gradually increased in width and depth by the second and third rolling rollers 7 , 8 until reaching to the width and depth finally made by the fourth rolling roller 9 . That is, the fourth rolling roller 9 , which is the final-stage rolling roller, finishes the final configuration of the first locking groove ( FIG. 2 ) or the second locking groove 4 ( FIGS. 3 and 4 ) of the pipe 2 .
- the first rolling roller 6 first rolls on the pipe 2 while keeping tight contact therewith and locally depresses the outer circumferential surface of the pipe 2 in form of a recess.
- the second and third rolling rollers 7 , 8 gradually getting larger in diameter sequentially roll on the pipe 2 to enlarge and deepen the recess. That is, the amount of depression for the recess made by sequential compression from the rolling rollers increases gradually.
- the fourth rolling roller 9 as the final-stage rolling roller rolls on the pipe 2 , and further enlarge and deepen the recess, and here is completed the final configuration of the first locking groove 3 or the second locking groove 4 .
- the shaping surfaces of the first to third rolling roller 6 ⁇ 8 used for preliminary shaping preferably has the relation of similar figures with the outer circumferential geometry of the final-stage rolling roller 9 used for final shaping as shown in FIG. 5 .
- the mark of the first rolling roller 6 was retained in the groove of the pipe 2 even after the final shaping by the final-stage rolling roller 9 . Therefore, it is desirable that shaping surfaces of the first to final rolling rollers have the relation of similar figures.
- the foregoing explanation has been made as using four rolling rollers 6 ⁇ 9 to form the first locking groove 3 or the second locking groove 4 in the pipe 2 by sequentially bringing them into tight rolling contact with the pipe 2 transversally of the pipe 2 .
- the number of stages of the rolling rollers is not limitative, and more stages (but not less than two) may be used for preliminary shaping and final shaping altogether.
- the foregoing explanation has been made as using a plurality of rolling rollers 6 ⁇ 9 getting greater in diameter from the one first entering into the guide hole 13 to the one finally entering into the guide hole 13 , and aligning their rotation centers on a common vertical line L.
- the rolling rollers may be equal in thickness as well, or may be different in thickness.
- the rolling rollers may be equal in diameter.
- the individual rolling rollers should be supported to lay their rotation centers gradually offset from that of the rolling roller 6 first compressing the workpiece 2 to the rolling roller finally compressing the pipe 2 by ⁇ L each in a direction normal to the direction of relative movement between the rolling rollers 6 ⁇ 9 and the pipe 2 .
- the biting depth B ( FIG. 5 ) of the rolling rollers into the pipe 2 corresponding to the amount of depression of the pipe 2 , can be increased gradually from that of the first compressing rolling roller 6 to that of the finally compressing rolling roller 9 .
- shaping surfaces of the rolling rollers may be either identical or similar (different in thickness) as explained with reference to FIG. 5 .
- FIG. 6 shows a roller support block 10 supporting three rolling roller 6 ⁇ 8 .
- the first and second rolling rollers are used for preliminary shaping, and the uppermost third rolling roller 8 is used for final shaping.
- FIGS. 7 and 8 show a test system 30 actually prepared as a recess-forming system according to an embodiment of the invention to confirm expected effects of the present invention.
- explanation is omitted about some of the components of the test system 30 , which are identical to components already explained in conjunction with FIG. 1 , by simply identifying them with common reference numerals.
- FIG. 7 shows a pipe holder 5 of the test system 30 .
- the pipe holder 5 has a pipe-receiving horizontal hole 31 horizontally penetrating the holder main body 12 and having a round cross section. Diameter of the pipe-receiving horizontal hole (hereafter simply called pipe hole) 31 is approximately equal to the diameter of the pipe 2 as a workpiece such that, when the pipe 2 is inserted into the pipe hole 31 , there is substantially no clearance between the pipe 2 and the pipe hole 31 .
- the pipe holder 5 further includes a sub block attached to one side surface of the holder main body 12 and having a horizontal groove continuous from the pipe hole 31 ; and a fixing block 11 having a horizontal groove 33 and removably attached to the sub block.
- the pipe holder 5 it is sufficient for the pipe holder 5 to envelope the entire circumference of the pipe 2 only in its segment nearest to the portion where the recess should be formed.
- the other segments of the pipe 2 need not be enveloped by the pipe holder over its entire circumference. Therefore, the terms, “envelope the pipe 2 ” used herein should be construed to envelope a part of the pipe 2 , in which a recess should be formed.
- the pipe holder 5 enveloping the pipe 2 has a rectangular guide hole 13 vertically penetrating the pipe holder 5 at a location adjacent to the pipe hole 31 .
- FIG. 8 shows a roller support block 10 that is another component of the test system 30 .
- the roller support block 10 includes a main body 40 having a rectangular cross-section and supporting two rolling roller 6 , 7 to permit free rotation in a vertically spaced relationship.
- the two rolling roller 6 , 7 are rotatably attached to the support block main body 40 via support shafts 15 , 16 intersecting with a vertical axial line L in alignment with the axial line of the support block main body 40 .
- Diameter D 1 of the first rolling roller 6 located lower is slightly smaller than the diameter D 2 of the second rolling roller 7 located upper as the final stage.
- the roller support block 10 is inserted into the guide hole 13 of the pipe holder 5 from above to position the first rolling roller 6 lower.
- the guide hole 13 defines a pair of opposed vertical grooves 37 (see FIG. 7 ) having a cross-sectional geometry corresponding to the shaping surfaces of the first and second rolling rollers 6 , 7 that project outwardly from side surfaces of the main body 40 of the roller support block 10 (see FIG. 8 ). It will be readily understood from the configuration of the vertical grooves 37 in the guide hole 13 that the rolling rollers 6 , 7 have shaping surfaces (outer circumferential surfaces) suitable for forming the locking groove 4 shown in FIG. 3 .
- One ( 37 a ) of the opposed vertical grooves 37 in the guide hole 13 which is adjacent to the pipe-receiving horizontal hole 31 , partly interferes with the pipe-receiving horizontal hole 31 and communicates with it through an aperture 35 (see FIG. 9 ).
- the shaping surfaces of the first and second rolling rollers 6 , 7 can compress the pipe 2 through the aperture 35 .
- FIG. 10 shows a part of the pipe 2 already having the locking groove 4 , and shows where the aperture 35 is positioned relative to the groove 4 when the groove is formed.
- the hatching in FIG. 10 shows the position of the aperture 35 .
- the aperture 35 has a contour in form of the peripheral edge of the locking groove 4 .
- a gap C may be provided between a perpendicular wall surface 36 (see FIG. 7 ) of the vertical groove 37 in the guide hole 13 and the perpendicular side surfaces 6 a , 7 a (see FIG. 9 ) of the first-stage and second-stage rolling rollers 6 , 7 for forming the engagement surface 4 a of the looking groove 4 a .
- the perpendicular wall surface 36 , perpendicular side surfaces 6 a , 7 a and engagement surface 4 a are planes perpendicular to the lengthwise direction of the pipe 2 held in the pipe-receiving hole 31 .
- the gap C equals 0.1 ⁇ 0.2 mm approximately.
- “sharp engagement surface with (or having) a clearly angled edge” means that the engagement surface of the recess extends straight inward of a workpiece in the direction crossing the lengthwise axis of the workpiece at a right angle, and makes a clearly angled edge at its terminal end nearer to the outer circumferential surface of the workpiece.
- “sharply angled edge” means that the border between the engagement surface 4 a and the outer circumferential surface of the pipe 2 or an intervening surface makes a clear angle not blunt or rounded.
- the engagement surface of the recess is formed to extend straight inward of the workpiece directly from the outer circumferential surface of the workpiece like those of the recesses 3 and 4 shown in FIGS.
- the “sharply angled edge” is the border between the engagement surface and the outer circumferential surface of the workpiece.
- the angle of the sharply angled edge is approximately a right angle.
- the edge of the engagement surface pertains to the border between the engagement surface and the sloping surface, and the angle of the edge will become larger than 90°.
- the pipe 2 is set in the pipe holder 5 and fixed from lengthwise displacement and rotation about the axis. Then, the roller support block 10 in the guide hole 13 is moved first down and next up to make one reciprocal motion. Thus, the locking groove 4 is formed in the pipe 4 . In the process of forming the locking groove 4 , since the pipe holder 5 envelopes the entire circumference of the pipe 2 , the test system 30 can prevent undesirable deformation of the pipe 2 caused by compression onto the pipe by form rolling.
- the pipe 2 used in the test was a high tension material, having a tensile strength not lower than 650 N/mm 2 , sized 12.7 mm in diameter and having the wall 1.4 mm thick. As a result, the locking groove 4 obtained has been confirmed to be in a practically satisfactory level without bluntness at the corner of the engagement surface 4 a.
- pipes 2 for headrest stays generally have a diameter around 10 ⁇ 13 mm.
- the pipes 2 used in the test were 12 mm and 12.7 mm in diameter, and the diameter of the final-stage rolling roller was 45 mm.
- the test system 30 has been explained.
- the first support axis 15 rotatably supports six first rolling rollers 6 ( 1 ) ⁇ 6 ( 6 ) side by side as FIG. 11 shows.
- the second support axis 16 rotatably supports six second rolling rollers 7 ( 1 ) ⁇ 7 ( 6 ) side by side.
- the third support axis 17 and fourth support axis 18 rotatably support six third rolling rollers 8 ( 1 ) ⁇ 8 ( 6 ) and six fourth rolling rollers 9 ( 1 ) ⁇ 9 ( 6 ) side by side, respectively.
- the first rolling roller 6 ( 1 ), second rolling roller 7 ( 1 ), third rolling roller 8 ( 1 ) and fourth (final) rolling roller 9 ( 1 ) constitute one set of rolling rollers for forming one locking groove 3 or 4 .
- the first to fourth rolling rollers 6 ( 2 ), 7 ( 2 ), 8 ( 2 ) and 9 ( 2 ) constitute another set of rolling rollers for forming another locking groove 3 or 4 .
- the common roller support block 10 shown here supports six sets of rolling rollers, and can be used to form six locking grooves 3 , 4 at close positions on one pipe 2 simultaneously.
- FIG. 12 merely shows the support axes 15 ⁇ 18 and omits illustration of rolling rollers on these axes.
- the fixing block 11 may be designed to use hydraulic pressure to fix the pipe 2 .
- FIG. 13 shows a recess-forming system 100 embodying the invention.
- the recess-forming system 100 is a remodeled machine from a mass-production model press.
- the roller support block 10 of the recess-forming system 100 is fixed at the lower end of a shaft 101 of a hydraulic cylinder (not shown), and movable up and down.
- a guide member 102 having a guide hole 13 is placed stationary, and a pipe holder 105 is located adjacent to the guide member 102 .
- the pipe holder 105 is composed of a lower holder 106 and an upper holder 107 .
- the upper holder 107 can be moved up and down by the hydraulic cylinder 108 .
- FIG. 15 is a view of the guide member 102 and the pipe holder 105 taken from a diagonally upper point.
- the guide hole 13 that receives the roller support block 10 is defined by the guide member 102 and the pipe holder 105 .
- five vertical grooves 109 a ⁇ 109 e are formed to permit rolling rollers to travel.
- Each of the vertical grooves 109 a ⁇ 109 e has a width substantially equal to the thickness of the outer circumferential portion of the final-stage rolling roller 9 .
- the roller support block 10 supports five sets of rolling rollers side by side, each set being composed of four rolling rollers 6 ⁇ 9 arranged in four vertical stages.
- the roller support bock 10 can form five locking grooves simultaneously in its single reciprocal movement in the vertical direction.
- the stationary lower holder 106 and the movable upper holder 107 have horizontal grooves 106 a , 107 a having a semicircular cross section, respectively.
- the semicircular grooves 106 a , 107 a are opposed to each other and, in combination, make a horizontal cylindrical hole receiving the pipe 2 .
- the horizontal cylindrical hole made by the semicircular grooves 106 a and 107 a is sized substantially equal to the outer contour of the pipe 2 at least over a partial length thereof for receiving the groove-forming portion of the pipe 2 .
- the other part of the horizontal cylindrical hole made by the semicircular grooves 106 a and 107 a may be sized larger than the diameter of the pipe 2 .
- the upper holder 107 is urged downward by the hydraulic cylinder 108 , and can firmly grip the pipe 2 to prevent undesirable rotation and displacement in the lengthwise direction. While the pipe 2 is gripped firmly in this manner, when the roller support block 10 moves vertically in the guide hole 13 by one reciprocation, sets of the first to final rolling rollers 6 ⁇ 9 form a corresponding number of locking grooves 3 , 4 simultaneously. When the piston 108 a of the hydraulic cylinder 108 withdraws, the upper holder 107 lifts up and loosens the grip to the pipe 2 to permit it to be removed from the pipe holder 105 .
- the pipe holder 105 may be convenient to divide the pipe holder 105 to right and left holder halves and fix one of these holder halves adjacent to the guide member 102 stationary while permitting the other to move.
- the pressure from the rolling rollers 6 ⁇ 9 may undesirably displace the movable holder half to the right or left though slightly.
- the pipe 2 may undesirably deform due to the stress produced by the forming of recesses.
- the semicircular horizontal grooves 106 a , 107 a make the horizontal cylindrical hole substantially equal in diameter to the pipe 2 , and prevents deformation of the pipe 2 when recesses are formed by the rolling rollers 6 ⁇ 9 .
- the invention is of course applicable to formation of recesses for check balls of hollow shift fork shafts. Furthermore, the invention is widely usable for forming recesses in pipes in general.
- the above-explained embodiment uses the pipe hole 31 (best shown in FIGS. 7 and 9 ) having a circular cross section. To reliably prevent withdrawal of the pipe 2 while the recesses 3 , 4 are formed, it is effective to provide a wall withholding the surface of the pipe 2 opposite from the recess-forming portion (shown by triangles in FIG. 10 ).
- the rolling rollers 6 ⁇ 9 are free-rotation rollers. However, they may be power-driven rollers that can rotate with power from a drive means.
- a single set of rolling rollers in multiple stages includes a single final-stage rolling roller.
- each set of multi-stage rolling rollers may include two or more final-stage rolling rollers.
- two or more final-stage rolling rollers are adjacent to each other, and they are identical in shape and size.
- aligning the center axes of the rolling rollers on a common straight line L see FIGS. 1 and 14
- two or more final-stage rolling rollers are of course aligned to lay their center axes on the common straight line L.
- two or more final-stage rolling rollers should be supported to lay their center axes on a common straight line.
Abstract
A roller support block 10 supports rolling rollers (6˜9) in four stages and moves in a guide hole (13) of a pipe holder (5) to sequentially bring the rolling roller into pressure contact with a pipe (2) held immovable by the pipe holder (5) through an aperture (35) made in the pipe holder (5). In this process, the first-stage rolling roller (6) first comes into rolling pressure contact with the pipe for preliminary shaping of a recess. Subsequently, the second-stage and third-stage rolling rollers (7, 8) advance the preliminary shaping to enlarge and deepen the recess. Finally, the fourth-stage rolling roller 9 finally shapes the recess to a first locking groove (3 or 4).
Description
- The present application is a continuation of International Patent Application No. PCT/JP2004/015542, filed Oct. 14, 2004 (incorporated herein by reference), which in turn claims priority from Japanese Patent Application No. JP2003˜353242, filed Oct. 14, 2003.
- The present invention relates to a method and a system for forming a recess in a tubular workpiece like a pipe.
- Modern compartment seats of vehicles are equipped with headrests to protect passengers' heads upon collision. Headrests are typically attached to seat backs via stays, and users can adjust them in height by pulling them up or pushing them down. A typical mechanism for adjustment of the headrest's height includes hooks anchored in a seat back, and a series of locking grooves formed along each headrest stay.
- In the history of headrests, their stays were first made of solid rods that are round in cross section, and solid rods were substituted by pipes (hollow cylinders). Further, along with recent movements toward lightweight vehicles, the use of thin-wall pipes is desirable.
- In case of solid rods and thick-wall pipes, locking grooves can be formed by locally cutting their walls with a cutter on a milling machine. However, grooves in thin-wall pipes, having walls thinner than the required depth of locking grooves, cannot be formed by cutting. Therefore, a different method is required to form grooves that indent from outer circumferential surfaces of thin-wall pipes to define sharp engagement surfaces having angled edges at their outer ends to maintain reliable engagement with hooks.
- Japanese Patent Laid-open Publication No. JP-H08-90126 proposes a method of forming locking grooves of a headrest stay of a support rod of a handbrake by inserting a core member inside a pipe and depressing the outer circumferential surface of the pipe with a punch.
- Japanese Patent Laid-open Publication No. JP-2000-197922 proposes a method of forming a recess in a hollow shift fork shaft of a manual transmission for receiving a check ball by suing a press machine under the presence of a core member inserted into the hollow shaft. This publication also proposes a method of removing the core member from the shaft after forming the recess by rotating the core member having a unique configuration.
- Japanese Patent Laid-open Publication No. JP-2002-137673 is directed to a method of forming locking grooves at opposed positions of two longer parallel segments of a headrest stay made of a channel-shaped pipe having the two longer segments connected by one shorter segment. This publication proposes to form locking grooves by thrusting the pipe between a pair of roll punches located face to face under the presence of support rolls set aside the roll punches to support them.
- Japanese Patent Laid-open Publication No. JP-2002-210519 proposes a method of forming locking grooves of a headrest stay through two manufacturing steps, i.e. a preliminary shaping step and a final shaping step. In the preliminary step, this method forms a recess indenting from the circumferential surface of a pipe by driving a rotating punch down onto the exposed circumferential surface of the pipe while supporting the pipe in an arcuate groove of a holder. In the next final shaping step, this method forms the locking groove by moving a press punch along a guide groove while covering the full circumference of the pipe with a holder cover having the guide groove extending along the recess.
- Japanese Patent Laid-open Publication No. JP-2003-9991 proposes a method of forming locking grooves of a headrest stay by thrusting a punch having an end surface of a unique configuration onto a pipe.
- Japanese Patent Laid-open Publication No. JP-2003-71522 proposes a method of forming locking grooves of a headrest stay by thrusting a press tool having a unique configuration onto the circumferential surface of a pipe while driving the tool transversally of the lengthwise direction of the pipe under the presence of a core member inserted in the pipe.
- To form a recess required to define such a sharp engagement surface at a portion of the outer circumferential surface of a pipe, just like a locking groove of a headrest stay, it is important to prevent bluntness of the edge of an engagement surface in the recess as the above-introduced publications point out as well.
- In addition, complicated tasks or steps for forming such recesses in a pipe invite an increase of the cost. Therefore, to reduce or minimize the cost, it is advantageous that recesses of a desired configuration can be formed in a pipe in a single manufacturing step.
- Under the circumstances, there is a need for a method and a system capable of forming a recess of desired configuration in a tubular workpiece like a pipe in a single continuous step.
- It is also desirable that such a recess can be formed in a tubular workpiece without inserting a core member inside the workpiece.
- There is a further need for a method and a system capable of forming such a recess in a tubular workpiece having a thin wall like a thin-wall pipe.
- It is also desirable that such a recess can be formed in a tubular workpiece having a thin wall and a high tensile force such as a thin-wall, highly tensile pipe.
- It is also desirable that a recess having a sharp engagement surface having an angled edge, such as a locking groove, can be formed on a tubular workpiece having a thin wall such as a thin-wall pipe in a single step.
- It is also desirable that such a recess can be formed in a straight tubular workpiece like a straight pipe before it is bent to a channel-shaped member, for example, such as a headrest stay.
- According to an embodiment of the invention, there is provided a method of forming a recess in a tubular workpiece comprising:
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- preparing a set of rolling rollers in multiple stages capable of sequentially interfering the workpiece in an intersecting direction;
- having the rolling rollers sequentially get into pressure contact with the workpiece by relative movement between the rolling rollers and the workpiece to bring about preliminary shaping and final shaping and thereby form the recess in the workpiece; and
- preparing a workpiece holder capable of holding the workpiece immovable by enveloping the workpiece and having an aperture through which the rolling rollers can sequentially interfere with the workpiece, wherein the rolling rollers get into pressure contact with the workpiece through the aperture.
- In this method, a workpiece holder having an aperture is preferably used to support the workpiece and expose a portion of the workpiece to be processed for forming the recess. To ensure that the recess defines a sharp engagement surface having an angled edge, at least a portion of the contour of the aperture adjacent to the engagement surface of the recess in the workpiece preferably makes substantially no gap from the contour of the final-stage rolling roller.
- According to another embodiment of the invention, there is provided a system for forming a recess in a tubular workpiece comprising:
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- a roller support block that holds a set of rolling rollers in multiple stages aligned in a row and permits the individual rolling rollers to rotate; and
- a workpiece holder having a workpiece-receiving hole substantially equal in cross-sectional configuration to the workpiece and capable of holding the workpiece immovably in the workpiece-receiving hole, said workpiece holder having an aperture exposing a part of the workpiece held in the workpiece-receiving hole,
- wherein the rolling rollers sequentially come into pressure contact with the workpiece through the aperture along with relative movement between the roller-receiving block and the workpiece holder, and thereby performing preliminary shaping and final shaping sequentially to form a recess in the workpiece.
- The workpiece holder may be divided in the moving direction of the roller support block. In case the roll support block moves vertically, the workpiece holder is divided to upper and lower portions, and one of the divisional portions may be moved to grip or release the workpiece inserted between them.
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FIG. 1 is a diagram for explaining the basic concept of the present invention; -
FIG. 2 is a cross-sectional view of a locking groove formed to indent from the outer surface of a pipe typically used as a headrest stay; -
FIG. 3 is a cross-sectional view of another locking groove formed to indent from the outer surface of a pipe typically used as a headrest stay; -
FIG. 4 is a cross-sectional view taken along the IV-IV line ofFIG. 3 : -
FIG. 5 is a diagram for explaining the outer circumferential configuration of rolling rollers used to form the locking groove shown inFIG. 3 ; -
FIG. 6 is a diagram for explaining a modification in positions of the rolling rollers; -
FIG. 7 is a perspective view of a pipe holder that is a component of a test system; -
FIG. 8 is a perspective view of a roller support block that is a component of the test system; -
FIG. 9 is a diagram showing how the rolling rollers locally depress a pipe; -
FIG. 10 is a diagram showing the contour of an aperture through which the rolling rollers can locally depress the pipe; -
FIG. 11 is a schematic plan view of a common roller support block preferably employed in a mass production type system; -
FIG. 12 is a schematic front elevation of the common roller support block preferably employed in the mass production type system; -
FIG. 13 is a schematic diagram of a modified system having rolling rollers held stationary to form recesses in moving pipes; -
FIG. 14 is a diagram for explaining the outline of a mass production type system remodeled from a press; and -
FIG. 15 is an upper diagonal view of a guide member having a guide hole and a pipe holder, which are located side by side. - Some embodiments and specific examples of the present invention will now be explained in detail with reference to the drawings.
-
FIG. 1 shows the basic concept of the invention for forming a recess in a tubular workpiece typically of a metal. The recess-forming system shown inFIG. 1 is used to form locking grooves of a headrest stay. - The headrest stay, as a final product, is a channel-shaped or M-shaped member made by bending a straight pipe to two longer pipe segments and one shorter pipe portion connecting the longer pipe segment, as already known in the art. The longer pipe segments have a plurality of locking grooves formed in intervals in their axial directions. The illustrated headrest stay has a first locking groove 3 (approximately 1.5 mm deep) having a channel-shaped cross section as shown in
FIG. 2 , and a second locking groove 4 (approximately 1.5 mm deep) defined by a vertical plane and an opposed tapered plane as shown inFIGS. 3 and 4 . The recess-formingsystem 1 can be used to form these first andsecond locking grooves - The recess-forming
system 1 can be used to form locking grooves in a pipe bent to the shape of a headrest stay from a straight pipe as existing techniques do. Moreover, the recess-formingsystem 1 can form locking grooves in a straight pipe before being bent to the form of a headrest stay. That is, lockinggrooves system 1, and the straight pipe may be bent later to manufacture a channel-shaped or M-shaped headrest stay. - To manufacture various types of headrest stays, it is advantageous to form a desired number of locking
grooves grooves grooves grooves - The recess-forming
system 1 includes apipe holder 5 for holding a pipe stationary, and aroller support block 10 that supports a plurality of rolling rollers (rolling dies for form rolling) 6˜9. Thepipe holder 5 includes a fixingblock 11 and amain holder block 12 that can tightly hold a pipe between them to prevent thepipe 2 from displacement in its lengthwise direction and rotation about the axial line. Thepipe holder 5 has aguide hole 13 formed to extend in the vertical direction at a position adjacent thepipe 2. - The rolling
rollers 6˜9 are supported by theroller support block 10 to align in intervals along the axial line of theguide hole 13, and supported for free rotation on theroller support block 10 byindividual shafts 15˜18. Theroller support block 10 is inserted into theguide hole 13 from above to work out a desired recess, i.e. the lockinggroove pipe 2 during a single reciprocal movement, preferably first down and next up, in theguide hole 13. - For easier explanation, the rolling rollers are individually named the first-
stage rolling roller 6, second-stage rolling roller 7, third-stage rolling roller 8, and fourth-stage rolling roller 9 from the one first entering into theguide hole 13 to the one finally entering same as shown inFIG. 1 . Further, the first-stage rolling rollers to the fourth-stage (final-stage) rollingrollers 6˜9 are often called the first rolling rollers to the fourth-stage (final-stage) rollingrollers 6˜9 hereafter. Thesupport shafts 15˜18 of the first tofourth rolling rollers 6˜9 lie on a common vertical line L parallel to the direction of relative movement between the rollingrollers 6˜9 and thepipe 2, and diameters D of the first tofourth rolling rollers 6˜9 gradually increase from thefirst rolling roller 6. - In greater detail, diameter D1 of the
first rolling roller 6 nearest to theguide hole 13, that is, nearest to thepipe 2 in position, is smaller than the diameter D2 of thesecond rolling roller 7 upwardly next to thefirst rolling roller 6. The diameter D2 of thesecond rolling roller 7 is smaller than the diameter D3 of thethird rolling roller 8. The diameter D3 of thethird rolling roller 8 is smaller than the diameter D4 of thefourth rolling roller 9. Here is the relation of D1<D2<D3<D4. - Outer circumferential surfaces of the first to
fourth rolling rollers 6˜9 have outer circumferential surfaces (hereinafter often called shaping surfaces as well) corresponding to the shape of the first locking groove 3 (FIG. 2 ) or the second locking groove 4 (FIGS. 3 and 4 ).FIG. 5 shows the shaping surface of the fourth rolling roller 9 (solid line) together with shaping surfaces of the first tothird rolling rollers 6˜8 (broken lines). It will be readily understood fromFIG. 5 that a groove (second groove 4 ofFIG. 3 in the illustrated example) first depressed shallow by thefirst rolling roller 6 is gradually increased in width and depth by the second andthird rolling rollers fourth rolling roller 9. That is, thefourth rolling roller 9, which is the final-stage rolling roller, finishes the final configuration of the first locking groove (FIG. 2 ) or the second locking groove 4 (FIGS. 3 and 4 ) of thepipe 2. - More specifically, when the
roller support block 10 moves under the guide by theguide hole 13 of thepipe holder 5, thefirst rolling roller 6 first rolls on thepipe 2 while keeping tight contact therewith and locally depresses the outer circumferential surface of thepipe 2 in form of a recess. Subsequently, the second andthird rolling rollers pipe 2 to enlarge and deepen the recess. That is, the amount of depression for the recess made by sequential compression from the rolling rollers increases gradually. After that, thefourth rolling roller 9 as the final-stage rolling roller rolls on thepipe 2, and further enlarge and deepen the recess, and here is completed the final configuration of thefirst locking groove 3 or thesecond locking groove 4. - The shaping surfaces of the first to
third rolling roller 6˜8 used for preliminary shaping preferably has the relation of similar figures with the outer circumferential geometry of the final-stage rolling roller 9 used for final shaping as shown inFIG. 5 . In a test actually carried out by using afirst rolling roller 6 having a relatively acuminate shaping surface, the mark of thefirst rolling roller 6 was retained in the groove of thepipe 2 even after the final shaping by the final-stage rolling roller 9. Therefore, it is desirable that shaping surfaces of the first to final rolling rollers have the relation of similar figures. - The foregoing explanation has been made as using four rolling
rollers 6˜9 to form thefirst locking groove 3 or thesecond locking groove 4 in thepipe 2 by sequentially bringing them into tight rolling contact with thepipe 2 transversally of thepipe 2. However, the number of stages of the rolling rollers is not limitative, and more stages (but not less than two) may be used for preliminary shaping and final shaping altogether. - The foregoing explanation has been made as using a plurality of rolling
rollers 6˜9 getting greater in diameter from the one first entering into theguide hole 13 to the one finally entering into theguide hole 13, and aligning their rotation centers on a common vertical line L. In this case, the rolling rollers may be equal in thickness as well, or may be different in thickness. - Alternatively, the rolling rollers may be equal in diameter. In this case, as shown in
FIG. 6 , the individual rolling rollers should be supported to lay their rotation centers gradually offset from that of the rollingroller 6 first compressing theworkpiece 2 to the rolling roller finally compressing thepipe 2 by ΔL each in a direction normal to the direction of relative movement between the rollingrollers 6˜9 and thepipe 2. Thereby, the biting depth B (FIG. 5 ) of the rolling rollers into thepipe 2, corresponding to the amount of depression of thepipe 2, can be increased gradually from that of the firstcompressing rolling roller 6 to that of the finally compressing rollingroller 9. In this modification using rolling rollers equal in diameter, shaping surfaces of the rolling rollers may be either identical or similar (different in thickness) as explained with reference toFIG. 5 . -
FIG. 6 shows aroller support block 10 supporting three rollingroller 6˜8. In this example, the first and second rolling rollers are used for preliminary shaping, and the uppermostthird rolling roller 8 is used for final shaping. -
FIGS. 7 and 8 show atest system 30 actually prepared as a recess-forming system according to an embodiment of the invention to confirm expected effects of the present invention. Hereunder, explanation is omitted about some of the components of thetest system 30, which are identical to components already explained in conjunction withFIG. 1 , by simply identifying them with common reference numerals. -
FIG. 7 shows apipe holder 5 of thetest system 30. Thepipe holder 5 has a pipe-receivinghorizontal hole 31 horizontally penetrating the holdermain body 12 and having a round cross section. Diameter of the pipe-receiving horizontal hole (hereafter simply called pipe hole) 31 is approximately equal to the diameter of thepipe 2 as a workpiece such that, when thepipe 2 is inserted into thepipe hole 31, there is substantially no clearance between thepipe 2 and thepipe hole 31. Thepipe holder 5 further includes a sub block attached to one side surface of the holdermain body 12 and having a horizontal groove continuous from thepipe hole 31; and a fixingblock 11 having ahorizontal groove 33 and removably attached to the sub block. When the fixing block is attached to the sub block, their horizontal grooves can make a pipe hole continuous from thepipe hole 31 in the holdermain block 12. Therefore, after thepipe 2 is inserted in and through thepipe hole 31 of the holdermain body 12 to partly lie on the horizontal groove of the sub block, once the fixingblock 11 is tightly attached to the sub block bybolts 34, thepipe 2 is enveloped over its entire circumference by thepipe holder 5 and prohibited in lengthwise displacement and rotation about its axis. - It is sufficient for the
pipe holder 5 to envelope the entire circumference of thepipe 2 only in its segment nearest to the portion where the recess should be formed. The other segments of thepipe 2 need not be enveloped by the pipe holder over its entire circumference. Therefore, the terms, “envelope thepipe 2” used herein should be construed to envelope a part of thepipe 2, in which a recess should be formed. Thepipe holder 5 enveloping thepipe 2 has arectangular guide hole 13 vertically penetrating thepipe holder 5 at a location adjacent to thepipe hole 31. -
FIG. 8 shows aroller support block 10 that is another component of thetest system 30. Theroller support block 10 includes amain body 40 having a rectangular cross-section and supporting two rollingroller - The two rolling
roller main body 40 viasupport shafts main body 40. Diameter D1 of thefirst rolling roller 6 located lower is slightly smaller than the diameter D2 of thesecond rolling roller 7 located upper as the final stage. - The
roller support block 10 is inserted into theguide hole 13 of thepipe holder 5 from above to position thefirst rolling roller 6 lower. Theguide hole 13 defines a pair of opposed vertical grooves 37 (seeFIG. 7 ) having a cross-sectional geometry corresponding to the shaping surfaces of the first andsecond rolling rollers main body 40 of the roller support block 10 (seeFIG. 8 ). It will be readily understood from the configuration of thevertical grooves 37 in theguide hole 13 that the rollingrollers groove 4 shown inFIG. 3 . - One (37 a) of the opposed
vertical grooves 37 in theguide hole 13, which is adjacent to the pipe-receivinghorizontal hole 31, partly interferes with the pipe-receivinghorizontal hole 31 and communicates with it through an aperture 35 (seeFIG. 9 ). The shaping surfaces of the first andsecond rolling rollers pipe 2 through theaperture 35. -
FIG. 10 shows a part of thepipe 2 already having the lockinggroove 4, and shows where theaperture 35 is positioned relative to thegroove 4 when the groove is formed. The hatching inFIG. 10 shows the position of theaperture 35. Theaperture 35 has a contour in form of the peripheral edge of the lockinggroove 4. However, a gap C may be provided between a perpendicular wall surface 36 (seeFIG. 7 ) of thevertical groove 37 in theguide hole 13 and theperpendicular side surfaces 6 a, 7 a (seeFIG. 9 ) of the first-stage and second-stage rolling rollers engagement surface 4 a of the lookinggroove 4 a. Theperpendicular wall surface 36,perpendicular side surfaces 6 a, 7 a andengagement surface 4 a are planes perpendicular to the lengthwise direction of thepipe 2 held in the pipe-receivinghole 31. In thistest system 30, the gap C equals 0.1˜0.2 mm approximately. However, in case of forming a locking groove configured as shown inFIG. 2 or 3, it is desirable to reduce the gap C to approximately zero in order to form thesharp engagement surface 4 a with a clearly angled edge. Therefore, to form thesharp engagement surface 4 a with a sharply angled edge, it is desirable that theaperture 35 has substantially no gap (C is substantially zero) relative to the final-stage rolling roller 7. The wording, “sharp engagement surface with (or having) a clearly angled edge”, means that the engagement surface of the recess extends straight inward of a workpiece in the direction crossing the lengthwise axis of the workpiece at a right angle, and makes a clearly angled edge at its terminal end nearer to the outer circumferential surface of the workpiece. The wording, “sharply angled edge”, means that the border between theengagement surface 4 a and the outer circumferential surface of thepipe 2 or an intervening surface makes a clear angle not blunt or rounded. In case the engagement surface of the recess is formed to extend straight inward of the workpiece directly from the outer circumferential surface of the workpiece like those of therecesses FIGS. 2 and 3 , the “sharply angled edge” is the border between the engagement surface and the outer circumferential surface of the workpiece. In this case, the angle of the sharply angled edge is approximately a right angle. In another form of recess (not shown) having an inner wall surface first sloping down inward of from the outer circumferential surface of the workpiece and then turns to the direction perpendicularly to the lengthwise axis of the pipe, the edge of the engagement surface pertains to the border between the engagement surface and the sloping surface, and the angle of the edge will become larger than 90°. - In use of the
test system 30, thepipe 2 is set in thepipe holder 5 and fixed from lengthwise displacement and rotation about the axis. Then, theroller support block 10 in theguide hole 13 is moved first down and next up to make one reciprocal motion. Thus, the lockinggroove 4 is formed in thepipe 4. In the process of forming the lockinggroove 4, since thepipe holder 5 envelopes the entire circumference of thepipe 2, thetest system 30 can prevent undesirable deformation of thepipe 2 caused by compression onto the pipe by form rolling. - The
pipe 2 used in the test was a high tension material, having a tensile strength not lower than 650 N/mm2, sized 12.7 mm in diameter and having the wall 1.4 mm thick. As a result, the lockinggroove 4 obtained has been confirmed to be in a practically satisfactory level without bluntness at the corner of theengagement surface 4 a. - The problem of bluntness or dullness of the edge of the engagement surface was examined. As a result, although the above-mentioned gap C around 0.1˜0.2 mm is acceptable, it has been confirmed more effective to minimize the gap C relative to the final-
stage rolling roller 7 in order to make an angled edge at the outer end of theengagement surface 4 a. In thetest system 30 intended to form grooves shown inFIG. 2 or 3, the contour of theaperture 35 is substantially the same as the contour of the final-stage rolling roller 7. - When the invention is used to form locking grooves of a headrest stay, two stages through five stages will be sufficient as the multiple stages of rolling rollers for systems of a mass-production model. Additionally, it has been confirmed that minimization of diameters D of the rolling rollers is effective to prevent bluntness because the contact surface of the rolling rollers with the
pipe 2 can be reduced. For example,pipes 2 for headrest stays generally have a diameter around 10˜13 mm. Forsuch pipes 2, it is desirable to limit the diameter of the final-stage rolling roller to the diameter of thepipe 2 or to the level of 1˜4 times the diameter of thepipe 2, or preferably in the range of 1˜3 times the diameter of thepipe 2. Thepipes 2 used in the test were 12 mm and 12.7 mm in diameter, and the diameter of the final-stage rolling roller was 45 mm. - Heretofore, the
test system 30 has been explained. When a recess-forming system of a mass-production model is designed under the same concept, it is recommended to prepare and simultaneously activate some roller support blocks 10 equal to the number of lockinggrooves pipe 2 to form the desired number of lockinggrooves pipe 2 needs some lockinggrooves roller support block 10 to rotatable support corresponding sets of first to final rolling rollers side by side. That is, as shown inFIGS. 11 and 12 , the commonroller support block 10 have foursupport axes 15˜18. Thefirst support axis 15 rotatably supports six first rolling rollers 6(1)˜6(6) side by side asFIG. 11 shows. Thesecond support axis 16 rotatably supports six second rolling rollers 7(1)˜7(6) side by side. Similarly, thethird support axis 17 andfourth support axis 18 rotatably support six third rolling rollers 8(1)˜8(6) and six fourth rolling rollers 9(1)˜9(6) side by side, respectively. In this commonroller support block 10, the first rolling roller 6(1), second rolling roller 7(1), third rolling roller 8(1) and fourth (final) rolling roller 9(1) constitute one set of rolling rollers for forming onelocking groove groove roller support block 10 shown here supports six sets of rolling rollers, and can be used to form six lockinggrooves pipe 2 simultaneously. Note thatFIG. 12 merely shows the support axes 15˜18 and omits illustration of rolling rollers on these axes. - In a recess-forming system of a mass-production model, the fixing
block 11 may be designed to use hydraulic pressure to fix thepipe 2. -
FIG. 13 shows a recess-formingsystem 100 embodying the invention. Hereunder, explanation is omitted about some of the components of the recess-formingsystem 100, which are identical to components already explained in conjunction withFIG. 1 , by simply identifying them with common reference numerals. The recess-formingsystem 100 is a remodeled machine from a mass-production model press. Theroller support block 10 of the recess-formingsystem 100 is fixed at the lower end of ashaft 101 of a hydraulic cylinder (not shown), and movable up and down. - Below the
roller support block 10, aguide member 102 having aguide hole 13 is placed stationary, and apipe holder 105 is located adjacent to theguide member 102. Thepipe holder 105 is composed of alower holder 106 and anupper holder 107. Theupper holder 107 can be moved up and down by thehydraulic cylinder 108. -
FIG. 15 is a view of theguide member 102 and thepipe holder 105 taken from a diagonally upper point. As shown inFIG. 15 , theguide hole 13 that receives theroller support block 10 is defined by theguide member 102 and thepipe holder 105. On oneside surface 105 a of thepipe holder 105 defining theguide hole 13, fivevertical grooves 109 a˜109 e are formed to permit rolling rollers to travel. Each of thevertical grooves 109 a˜109 e has a width substantially equal to the thickness of the outer circumferential portion of the final-stage rolling roller 9. In other words, theroller support block 10 supports five sets of rolling rollers side by side, each set being composed of four rollingrollers 6˜9 arranged in four vertical stages. Thus, theroller support bock 10 can form five locking grooves simultaneously in its single reciprocal movement in the vertical direction. - As shown in
FIG. 14 , the stationarylower holder 106 and the movableupper holder 107 havehorizontal grooves semicircular grooves pipe 2. The horizontal cylindrical hole made by thesemicircular grooves pipe 2 at least over a partial length thereof for receiving the groove-forming portion of thepipe 2. The other part of the horizontal cylindrical hole made by thesemicircular grooves pipe 2. - Still referring to
FIG. 14 , theupper holder 107 is urged downward by thehydraulic cylinder 108, and can firmly grip thepipe 2 to prevent undesirable rotation and displacement in the lengthwise direction. While thepipe 2 is gripped firmly in this manner, when theroller support block 10 moves vertically in theguide hole 13 by one reciprocation, sets of the first tofinal rolling rollers 6˜9 form a corresponding number of lockinggrooves piston 108 a of thehydraulic cylinder 108 withdraws, theupper holder 107 lifts up and loosens the grip to thepipe 2 to permit it to be removed from thepipe holder 105. - In a certain environment, it may be convenient to divide the
pipe holder 105 to right and left holder halves and fix one of these holder halves adjacent to theguide member 102 stationary while permitting the other to move. In this design, when four-stage rolling rollers 6˜9 apply pressure to thepipe 2 during vertical reciprocation of theroller support block 10, the pressure from the rollingrollers 6˜9 may undesirably displace the movable holder half to the right or left though slightly. In this case, thepipe 2 may undesirably deform due to the stress produced by the forming of recesses. - However, in the state where the
upper holder 107 overlies thelower holders 106, the semicircularhorizontal grooves pipe 2, and prevents deformation of thepipe 2 when recesses are formed by the rollingrollers 6˜9. - Heretofore, application of the invention to locking grooves of a headrest stay has been explained. However, the invention is of course applicable to formation of recesses for check balls of hollow shift fork shafts. Furthermore, the invention is widely usable for forming recesses in pipes in general.
- Although some embodiments have been explained, it should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors and that the present invention contemplates these modifications, combinations, sub-combinations and alterations insofar as they are within the scope of the appended claims or the equivalents thereof. For example, the invention contemplates the following modifications among others.
- (1) The embodiments have been explained as moving the rolling
rollers 6˜9 relative to thepipe 2 to form the lockinggrooves pipe 2 relative to the rollingrollers 6˜9. That is, it is sufficient that the rollingrollers 6˜9 sequentially interfere with thepipe 2. Therefore, as shown inFIG. 13 , a plurality ofpipes 2 may be set movable to move transversally of rollingrollers 6˜9 that are rotatable at fixed positions. In this case, the process of formingrecesses pipes 2 transversally of the rollingrollers 6˜9, for example, from left to right, or in one reciprocal movement of thepipes 2. - (2) As a method of supporting the
pipe 2, the above-explained embodiment uses the pipe hole 31 (best shown inFIGS. 7 and 9 ) having a circular cross section. To reliably prevent withdrawal of thepipe 2 while therecesses pipe 2 opposite from the recess-forming portion (shown by triangles inFIG. 10 ). - (3) In the foregoing embodiments, the rolling
rollers 6˜9 are free-rotation rollers. However, they may be power-driven rollers that can rotate with power from a drive means. - (4) In the foregoing embodiments, a single set of rolling rollers in multiple stages includes a single final-stage rolling roller. However, each set of multi-stage rolling rollers may include two or more final-stage rolling rollers. In this case, two or more final-stage rolling rollers are adjacent to each other, and they are identical in shape and size. In the embodiments aligning the center axes of the rolling rollers on a common straight line L (see
FIGS. 1 and 14 ), two or more final-stage rolling rollers are of course aligned to lay their center axes on the common straight line L. In the embodiment using rolling rollers equal in diameter, although the rolling roller in different stages are sequentially offset by Δ (seeFIG. 6 ), two or more final-stage rolling rollers should be supported to lay their center axes on a common straight line.
Claims (20)
1. A method of forming a recess in a tubular workpiece comprising:
preparing a set of rolling rollers in multiple stages capable of sequentially interfering the workpiece in an intersecting direction;
having the rolling rollers sequentially get into pressure contact with the workpiece by relative movement between the rolling rollers and the workpiece to bring about preliminary shaping and final shaping and thereby form the recess in the workpiece; and
preparing a workpiece holder capable of holding the workpiece immovable by enveloping the workpiece and having an aperture through which the rolling rollers can sequentially interfere with the workpiece,
wherein the rolling rollers get into pressure contact with the workpiece through the aperture.
2. The method according to claim 1 wherein the final-stage rolling roller among the set of rolling rollers, which finally comes into pressure contact with the workpiece, makes substantially no gap between side edges thereof and opposed edges of the aperture, and thereby forms the recess with a sharp engagement surface.
3. The method according to claim 2 wherein the contour of the recess is substantially equal to the contour of the aperture.
4. The method according to claim 1 wherein the multi-step rolling rollers are freely rotatable.
5. The method according to claim 4 wherein diameters of the multistage rolling roller are smaller the four times the diameter of the workpiece.
6. The method according to claim 1 further comprising:
preparing plural sets of the rolling rollers in multiple stages, and using them simultaneously to a plurality of said recesses simultaneously.
7. A method of forming a recess in a tubular workpiece, comprising:
preparing a workpiece holder having an aperture through which the rolling rollers can sequentially interfere with the workpiece and capable of holding the workpiece immovably by enveloping the circumference thereof, and a set of rolling rollers in multiple stages capable of getting in pressure contact with the workpiece through the aperture; and
having the rolling rollers sequentially get into pressure contact with the workpiece through the aperture to bring about preliminary shaping and final shaping and thereby form the recess in the workpiece.
8. The method according to claim 7 wherein all of the rolling rollers in multiple stages are identical in diameter, and center axes of the rolling rollers in different stages are sequentially offset in the direction perpendicular to the lengthwise axis of the workpiece held in the workpiece holder.
9. The method according to claim 7 wherein the rolling rollers in different stages vary in diameter sequentially in one direction, and center axes of all rolling rollers in multiple stages lie on a straight line parallel to the lengthwise axis of the workpiece held in the workpiece holder.
10. A system for forming a recess in a tubular workpiece comprising:
a roller support block that holds a set of rolling rollers in multiple stages aligned in a row and permits the individual rolling rollers to rotate; and
a workpiece holder having a workpiece-receiving hole substantially equal in cross-sectional configuration to the workpiece and capable of holding the workpiece immovably in the workpiece-receiving hole, said workpiece holder having an aperture exposing a part of the workpiece held in the workpiece-receiving hole,
wherein the rolling rollers sequentially come into pressure contact with the workpiece through the aperture along with relative movement between the roller-receiving block and the workpiece holder, and thereby performing preliminary shaping and final shaping sequentially to form the recess in the workpiece.
11. The system according to claim 10 wherein plural sets of rolling rollers in multiple stages are provided.
12. The system according to claim 10 wherein one of the rolling rollers in the final stage in each set makes substantially no gap between a side edge of the outer circumferential portion thereof and the contour of the aperture, and can make a sharp engagement surface having an angled edge in the recess in the workpiece in alignment with the contour of the aperture.
13. A system for forming a recess in a tubular workpiece comprising:
a roller support block that holds a set of rolling rollers in multiple stages vertically aligned in a row and permits the individual rolling rollers to rotate;
a guide member having a guide hole for guiding vertical movements of the roller support block;
a hydraulic cylinder vertically driving the roller support block under the guide by the guide hole; and
a workpiece holder located horizontally adjacent to the guide member and having a workpiece-receiving hole having a contour substantially identical to the cross-sectional configuration of the workpiece at least in a portion thereof for supporting a portion of the workpiece to be processed to form a recess therein, said workpiece holder being capable of holding the workpiece immovably in the workpiece-receiving hole,
wherein said workpiece holder having an aperture through which the rolling rollers can sequentially interfere with the workpiece held immovably in the workpiece-receiving hole to permit the rolling rollers in multiple stages to come into pressure contact with the workpiece and thereby perform preliminary shaping and final shaping sequentially to form the recess in the workpiece.
14. The system according to claim 13 wherein the roller support block supports horizontally aligned plural sets of the rolling rollers in multiple vertical stages.
15. The system according to claim 13 wherein the aperture has a contour substantially equal to the contour of the recess formed in the workpiece.
16. The system according to claim 13 wherein one of the rolling rollers in the final stage makes substantially no gap between a side edge of the outer circumferential portion thereof and a side edge of the aperture, and can make a sharp engagement surface having an angled edge in the recess in the workpiece in alignment with said side edge of the aperture.
17. The system according to claim 13 wherein the workpiece holder is composed of a lower holder half and a upper holder half both having elongated grooves in form of upper and lower halves of said workpiece-receiving hole, said upper holder half being driven vertically by a second hydraulic cylinder.
18. The system according to claim 12 wherein the rolling rollers in multiple stages have the relation of similar figures.
19. A method of forming a recess in a tubular workpiece held immovably, comprising:
preparing a set of rolling rollers identical in diameter and aligned in a row perpendicular to the lengthwise direction of the workpiece; and
having the rolling rollers sequentially roll on and compress the workpiece along with relative movement between the rolling rollers and the workpiece to form a recess at the compressed portion of the workpiece, said recess having a plane perpendicular to the lengthwise direction of the workpiece,
wherein center axes of said rolling roller equal in diameter are gradually offset from an imaginary line parallel to said relative movement so that the amount of depression of the pipe made by sequential compression by the rolling rollers increases gradually.
20. The method according to claim 2 wherein the multi-step rolling rollers are freely rotatable.
Priority Applications (1)
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US11/071,888 US20050210947A1 (en) | 2003-10-14 | 2005-03-03 | Method and system for forming a recess in a tubular workpiece |
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JP2003353242 | 2003-10-14 | ||
JP2003-353242 | 2003-10-14 | ||
PCT/JP2004/015542 WO2005035159A1 (en) | 2003-10-14 | 2004-10-14 | Method and apparatus for forming recess of hollow pipe |
US11/071,888 US20050210947A1 (en) | 2003-10-14 | 2005-03-03 | Method and system for forming a recess in a tubular workpiece |
Related Parent Applications (1)
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PCT/JP2004/015542 Continuation WO2005035159A1 (en) | 2003-10-14 | 2004-10-14 | Method and apparatus for forming recess of hollow pipe |
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US20050210947A1 true US20050210947A1 (en) | 2005-09-29 |
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US11/071,888 Abandoned US20050210947A1 (en) | 2003-10-14 | 2005-03-03 | Method and system for forming a recess in a tubular workpiece |
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KR100768389B1 (en) | 2007-03-14 | 2007-10-18 | 최순봉 | Apparatus for working the groove of headrest stay and method thereof |
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EP2759353A4 (en) * | 2011-09-05 | 2015-07-15 | Teknia Mfg Group S L | Device for machining notches in headrest tubes |
CN106425330A (en) * | 2016-12-09 | 2017-02-22 | 舟山市弘美机械制造有限公司 | Method for machining headrest rod open groove and rolling groove die thereof |
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US20050034499A1 (en) * | 2003-08-13 | 2005-02-17 | Shinsuke Matsumoto | Processing method of forming a concavity in a pipe member and an apparatus thereof |
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US20050034499A1 (en) * | 2003-08-13 | 2005-02-17 | Shinsuke Matsumoto | Processing method of forming a concavity in a pipe member and an apparatus thereof |
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KR100768389B1 (en) | 2007-03-14 | 2007-10-18 | 최순봉 | Apparatus for working the groove of headrest stay and method thereof |
WO2012101301A1 (en) * | 2011-01-28 | 2012-08-02 | Teknia Manufacturing Group, S.L. | System for machining notches in a head-restraint tube |
ES2386665A1 (en) * | 2011-01-28 | 2012-08-24 | Teknia Manufacturing Group S.L. | System for machining notches in a head-restraint tube |
EP2759353A4 (en) * | 2011-09-05 | 2015-07-15 | Teknia Mfg Group S L | Device for machining notches in headrest tubes |
US20170348821A1 (en) * | 2016-06-06 | 2017-12-07 | United Technologies Corporation | Deep roll peening system and method |
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US11673227B2 (en) | 2016-06-06 | 2023-06-13 | Raytheon Technologies Corporation | Deep roll peening system and method |
CN106425330A (en) * | 2016-12-09 | 2017-02-22 | 舟山市弘美机械制造有限公司 | Method for machining headrest rod open groove and rolling groove die thereof |
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