United States Patent
`Tuberman
`
`[151
`1451
`
`3,695,087
`Oct. 3, 1972
`
`[54] METHOD AND APPARATUS FOR
`POINTING TUBES
`
`397,343
`35,625
`
`8/1933 ‘Great Britain ............. ..72/367
`4/1955
`Poland ....................... ..72/402
`
`[72] Inventor:
`
`[22] Filed:
`
`St
`V " w e’
`Aug. 26, 1970
`
`60w‘
`
`‘
`
`Primary Examiner-eCharles W. Lanham
`Assistant Examiner-Gene P. Crosby
`Attorney-Fulwider, Patton, Rieber, Lee & Utecht
`
`[52] _ US. Cl ...................................... "72/402, 72/452
`[51] Int. Cl. ........................................... ..Bzld 41/04 .
`[53] Field of Search ------ --72/402’ 367, 36913998400’
`72/410, 452’ 463, 469’ 470, 472; 18"MG- 5
`_
`References Cited
`
`[56]
`
`UNITED STATES PATENTS
`3,478,565 11/1969
`Schenk .............. .; ...... ..72/399
`2,589,142
`3/1952
`Rotheroe .......... .; ....... ..72/400
`3,068,929 12/1962
`Rowell ....................... ..72/400
`3 292,414 12/1966 Goeke ....................... ..72/402
`3:4l7,598 12/1968
`Valente ..................... ..72/383
`3,509,785
`5/1970
`Fuchs ........................ ..72/347
`.
`,
`FOREIGN PATENTS QR APPLICATIONS
`
`372,543
`
`5/1932
`
`Great Britain ..... .; ...... ..72/367
`
`Method and apparatus for forming a generally cylin
`drical point on a tube by ?rst ?attening the tube from
`at least three sides to a polygonal cross section while
`forming curved sections between the ?at sides, and
`then progressively contracting the tube to bring the
`curved sections together while buckling the ?at sides
`inwardly into loops that are ?attened inside the point.
`At least three die shoes arranged around a die recess
`in alternately overlapping relation have ?at inner faces
`with an elongated lip along one side for Shaping the
`curved Sections, and also have ?at, inclined bevels for
`Shaping the transition Zone of the tube during point
`ing’ each bevel having a Pan-conical “P on One Side
`for the ?nal Shaping of the transition 1998 ‘0 a °°ni¢al
`shape: one ‘imma‘mg arrange?“ will“ a mutual
`cammmg action to move all d1e shoes simultaneously
`at the same rate to maintain the point on a preselected
`'
`h'l
`'
`l
`f
`d' 1
`th
`'
`‘
`2239:; e a Slmp er om ' ‘Sp aces
`e was durmg
`
`449,558
`1,035,352
`
`9/ 1927v Germany ................... ..72/402 -
`4/1955 Germany .............. ..l8/DlG. 5
`
`‘
`
`'
`16 Claims, 27 Drawing Figures
`
`17/
`
`22/
`
`Page 1 of 11
`
`EDWARDS LIFESCIENCES EX. 1216
`Edwards Lifesciences v. Boston Scientific Scimed
`U.S. Patent No. 6,915,560
`
`

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`PATENTED OCT 3
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`AP TTORNEVE |
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`Page 2 of 11
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`Page 2 of 11
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`Page 3 of 11
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`Page 3 of 11
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`

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`PATENTED OCT 3
`i972
`PATENTEB B81 3 1972
`
`3,895,087
`3,695,087
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`SHEEI 3 0F 3
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`ARTHURHl.TUBERNIAN
`BYGulinelr (ailon,
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`Page 4 of 11
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`Page 4 of 11
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`

`

`1 .
`-METHOD AND APPARATUS FOR POINTING
`
`'
`
`TUBES
`
`.
`
`3,695,087
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`5
`
`2
`Moreover, many tube materials are “notch sensi
`tive,” that is, tend to break under stress wherever a
`notch or groove has been fomied during pointing.
`Thus, any pointer which notches the tube during point
`ing, particularly in or around the transition zone,
`produces a likelihood of failure during subsequent
`operations. Of course, ruggedness, durability and rela
`tive simplicity of construction, as well as economy in
`construction, operation and maintenance, are primary
`objects of any production machine, and certain of the
`prior art machines, such as those requiring interleaved
`ribs, are de?cient in these respects.
`
`BACKGROUND OF THE INVENTION
`This invention relates to the fomiing of reduced
`diameter end portions on tubes for use in gripping the
`tubes during an operation such as drawing through a
`die. Such reduced-diameter end portions (called “
`points” although they typically are generally cylindrical
`or have some other blunt~ended shape) are necessary
`because the original tubing to be drawn through the die
`has a larger outside diameter than the diameter of the
`die, and also to provide a portion of the tube that can
`be gripped securely to apply the drawing force.
`Tube pointing machines of various types are known
`and have been used by the trade. For example, U.S.
`Pat. No. 3,292,414 shows an apparatus for swaging
`points with a plurality of arcuate reciprocating die seg
`ments which compress a tube as the arcuate faces of
`the dies are pressed together around the tube. Rotary
`swaging also has been used. In another,. somewhat
`similar approach, represented by U.S. Pat. No.
`3,073,374, a tube is positioned'between two dies hav
`25
`ing semi-cylindrical, concave faces and is pinched and '
`pleated from opposite sides before the semi-cylindrical
`dies are closed around the tube.
`'
`" In still another approach, shown in U.S. Pat. No.
`3,068,929, a tube is positioned over an open-sided, part
`polygonal recess and then forced into the recess by two
`rams which, when moved toward the open side of the
`recess, compress the tube into the recess and cooperate
`therewith to form a regular polygonal cavity in which
`the tube is collapsed and compacted to the desired
`shape. A similar result is obtained by the pointer shown
`in U.S. Pat. No. 3,417,598 in which four dies arranged
`around the end of a tube- are formed with interleaved
`?at-edged ribs which permit the dies. to' be moved
`~together to crush the end portion of the tube into a
`point.
`While these and other known pointers are capable of
`producing usable points on tubes, all of the pointers
`presently available are subject to one or more de?cien
`cies that have prevented the achievement of optimum
`results. Speci?cally, many of the machines produce an
`excessively high noise level as an incident to the point
`ing operation, or require rather complicated and dif
`?cult-to-maintain machinery. More importantly,
`despite claims that points can be formed completely in
`one stroke, it often is necessary to repeat the forming
`stroke several times in order to obtain a proper point,
`probably because most of the die systems inherently in
`clude gaps into which the metal can be displaced dur
`ing pointing. At the same time, it is difficult, if at all
`possible, to obtain uniformity in point diameters while
`maintaining the points concentric with the tubes.
`‘ The con?guration of the transition zone between the
`point and the body of the tube is particularly important
`from the standpoint of performance of the tube during
`subsequent drawing operations. If the tube is folded
`with nonuniform convolutions or distinct creases, par
`ticularly in the transition zone, as is common in some of
`65
`the prior pointers, stress risers are set up and can result
`in cracks which propagate down the tube». during the
`‘ drawing operations.
`
`50
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`20
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`30
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`35
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`45
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`55
`
`SUMMARY OF THE INVENTION
`The present invention resides in an improved tube
`pointer which produces superior and uniform points in
`a novel manner by positively guiding and controlling
`the bending of the tube material at all times, both in the
`zone of the point and in the_transition zone, while
`eliminating gaps in the die apparatus that could result _
`in uncontrolled bending or objectionable displacement
`of the tube wall. Moreover, the tube pointer of the in
`vention is capable of forming such points in a single and
`rapid one-stroke operation, is relatively simple, durable
`and quiet in operation, avoids cracks and objectionable
`creases in the transition area, and can maintain the
`point precisely concentric with the tube, thereby avoid- ,
`ing the disadvantages or prior pointers.
`To the foregoing ends, the pointer includes a die hav
`ing at least three die shoes that are arranged around
`and de?ne an open-ended die recess of generally
`polygonal cross section and are inter?tted to permit the
`shoes to move inwardly and outwardly, radially of the
`tube, to contract and expand the recess, the shoes hav
`ing substantially ?at inner working faces which form
`the tube ?rst into a generally polygonal cross-sectional
`shape as the shoes move inwardly to contract the
`recess. The shoes also include means for shaping the
`tube between the sides of the polygonal cross section
`into arcuate sections so that continued inward move
`ment of the shoes progressively shortens the sides of
`the polygonal cross section to buckle and fold the sides
`inwardly while moving the‘ arcuate sections toward
`each other, ?nally squeezing the arcuate sections sub
`stantially together into a generally cylindrical point
`with the buckled portions formed as flattened loops
`within the point.
`Controlled formation of the transition zone of the
`tube is accomplished by substantially ?at bevels on the
`die shoes which have the same slope away from the
`working faces as the desired angle of the cone of the
`transition zone, the bevels also having means thereon
`for closing conically around the transition zone as the
`arcuate sections of the point are brought together. The
`controlled buckling of the point zone and the con
`trolled sinking of the bevels into the tube cooperate to
`form uniform folds or convolutions inthe transition
`zone with soft creases that ?are from the point toward
`the tube into wide and gently rounded ends at the junc
`tion with the tube.v
`To permit such progressive contraction of die shoes
`having ?at working faces, the shoes are arranged in al
`ternately overlapped relation so that an edge of one
`shoe slides along the working face of one adjacent
`shoe, while an edge of the other adjacent shoe slides
`
`Page 5 of 11
`
`

`

`4
`FIG. 13 is a view similar to FIG. 12 with the die
`closed on a tube;
`FIG. 14 is an end view of the pointer in FIG.- 12 with
`a front cover plate thereof partly broken away; '
`FIGS. 15 to 19 are sequential views similar to FIGS.
`7 to 11 illustrating the bending of a tube to a point with
`the pointer of FIGS. 12 to 14;
`'
`FIGS. 20 and 21 are views similar to FIG. 14 illustrat
`ing an alternative manner of support and actuation of
`the die shoes of a four-shoe pointer;
`>
`FIG. 22 is a fragmentary perspective view of a die
`shoe of the type used in the pointer of FIGS. 20 and 21;
`FIGS. 23 and 24 are fragmentary views showing the
`arrangement of die shoes in a pointer having six die
`shoes, FIG. 23 showing the open position and FIG. 24
`showing the closed position; and
`-
`-
`FIGS. 25 and 26 are fragmentary views similar to
`FIGS. 23 and 24 but showing the arrangement of die
`shoes in a pointer having eight shoes. .
`
`3,695,087
`
`3
`along the Working face of the first shoe. The illustrative
`arcuate shaping means for the point comprise ?llets
`overlying the junctions between the working faces and
`having concave inner surfaces constituting longitudinal
`‘sections of a cylinder, and the corresponding means for
`the transition ‘zone comprise longitudinal sections of a
`cone overlying the junctions between the bevels.
`The concentricity of the point and the tube are main
`tained in the preferred forms of the invention by mov
`ing each die shoe toward the axis of the tube at the
`same rate, and this is accomplished with a single actua
`tor which shifts one of the'die shoes toward the axis at
`the desired‘ rate while the remaining shoes are cammed
`inwardly at the same rate in response to‘ the driving
`force applied by the actuator. Thus, the arcuate sec
`tions of the shoes can be maintained concentric with
`the tube at all stages of the pointing operation.
`Other objects and advantages of the invention will
`become apparent from the accompanying detailed
`description, taken in conjunction with the accompany
`‘ ing drawings‘.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective view of the basic components
`‘of a'tube pointer embodying the novel features. of the
`present invention, with a length of tubing in position for
`insertion into the pointer, a representative actuator
`partially broken away and shown in cross section, and
`parts of the pointer shown partly in broken lines for
`
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`20
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`clarity;
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`v
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`FIG. 2 is an enlarged fragmentary cross-sectional
`view’of the pointer in FIG. 1, taken substantially along
`the line 2—2 thereof, after the tube to be pointed has
`been inserted in the open die;
`_ FIG. 3 is a view ‘similar to FIG. 2 showing the pointer
`and- tube after the die has been closed to form the
`
`35
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`point;
`
`.
`
`.
`
`g
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`DETAILED DESCRIPTION
`As shown in the drawings for purposes of illustration,
`and with speci?c reference to FIGS. 1-11, the inven
`tion is embodied in a tube pointer 10 for forming a
`reduced diameter end portion or “point” 11 (see FIG.
`6) on a tube 12, for subsequent use in gripping the tube
`and pulling it through a drawing die (not shown) for a
`conventional- purpose such as redrawing of tubing
`where the diameter is to be reduced, the wall thickness
`is to be changed, and the like, to obtain the different
`sizes, shapes and other characteristics required in in
`dustry. The point may be inserted through such a die
`and then gripped in a suitable chuck with which the
`drawing force is applied.
`_
`In general, the pointer 10 includes a pointing die 13
`formed by a set of die shoes which are arranged around
`and define a recess 14 that is open at one end to receive
`the end of the tube 12 to be pointed. The die set is
`mounted in a case including a top member 15 above
`the die shoes, side members 17 depending from op
`posite edges of the top member, and a bottom member
`18 below the shoes. Herein, the case is supported
`between a pair of spaced front and rear guides 19 and
`20 upstanding from and bolted to a suitable base 21,
`such as a table, and connected by bars 22. Each of the
`illustrative guides has upright ?anges 23 (FIG. 1) which
`straddle the front and rear edges of the side members
`17 and support the latter and the top member 15 for up
`and down motion, toward and away from the table 21
`and the bottom member 18. This up and down motion
`is used to expand and contract the die recess 14 by
`moving the die shoes alternately outwardly, away from
`each other, into the open condition shown in FIGS. 1
`and 2, for insertion of a tube 12 in the pointer 10, and
`then inwardly toward each other into the closed condi
`tion (FIG. 3) to compress the portion of the tube within 7
`the die recess and form the reduced diameter point 11
`thereon. It should be understood, however, that this is
`only one‘of various arrangements that may be used to
`support the die.
`In accordance with the primary aspect of the present
`invention, at least three die shoes 24, 25 and 26 are ar
`ranged around the die recess 14 and have inner work
`ing faces 27 that initially de?ne the recess with a
`generally polygonal cross section, and are ?tted
`
`. FIG. 3A is an enlarged fragmentary cross section
`taken substantially along the lines 3A—3A of FIG. 3;
`FIG. 4 is an ‘enlarged fragmentary perspective view
`of one of the die shoes of the pointer;
`FIG. 5 is a fragmentary plan view of the die shoe of
`FIG. 4;
`-
`-
`FIG. 6 is an enlarged fragmentary perspective view
`of a pointed tube;
`FIG. 7 is an enlarged end view of a representative
`tube with the die shown schematically at the beginning
`of the pointing operation;
`FIG. 8 is a view similar to FIG. 7 showing the ?rst
`stage of bending of the tube during the initial closing of
`the die in which the tube- is generally polygonal in cross
`section and the ?at sides are connected by arcuate sec
`tions;
`FIG. 9 is a similar view showing the next stage of
`. bending as the walls of the tube begin to buckle during
`shortening of the ?at sides;
`' FIG. 10 is a similar view showing the next stage as the
`buckling continues and loops begin to form;
`FIG. 1 l is a similar view showing another stage as the
`loops are ?attened and compressed and the arcuate
`sections are brought together;
`, FIG. 12 is‘ a cross-sectional view similar to FIG. 2 on
`a somewhat reduced scale illustrating an alternative
`form of the pointer having four die shoes, the die being
`open;
`
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`Page 6 of 11
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`

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`3,695,087.
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`5
`together to permit the shoes to be moved simultane
`ously- inwardly, toward each other, to bend the tube ini
`tially to the polygonal cross section and then to con
`tractthe cross section progressively as such movement
`continues; In addition, the die shoes have curved sur
`faces 28 shaping the portions of the tube between the
`sides of the polygonal cross section into ‘curved sec
`tions, which are squeezed progressively toward each
`other as the die shoes are closed. Accordingly, the con
`tinued shortening of the sides, accompanying the
`squeezing of the curved sections toward each other,
`causes the portions of the tube between the curved sec
`tions to buckle inwardly in a controlled and predictable
`manner, forming loops which are ?attened and com
`pressed within the point as the curved sections are
`brought together to form the periphery of the point.
`' In its broader aspects, the invention also contem
`plates the control of the formation of the transition
`zone 29 of the tube 12 in a novel manner‘where the
`outside diameter increases from that of the point 11 to
`that of the body of the tube. For this purpose, each die
`shoe 24, 25, 26 has a bevel 30 that is inclined outwardly
`and forwardly from the front of the working face 27 at
`a selected angle relative to the axis of the tube. These
`bevels sink progressively into the tube from all sides as
`the point is formed, and insure that the folds or' con
`volutions (indicated generally at 31 in FIG. 6) in the
`transition zone are formed uniformly and without ob
`jectionable creases or notches. Finally, curved surfaces
`32 between the bevels close conically around the
`transition zone as the curved surfaces 28 close around
`the remainder of the point.
`In the illustrative embodiment shown in FIGS. 1-5,
`each‘ die shoe 24-26 is shown as having the ?at working
`face 27 disposed in a plane parallel to the axis of the
`tube 12, the three working faces being identical and
`cooperating to de?ne the recess 14 with the general
`cross-sectional shape of an equilateral triangle, as
`shown most clearly in FIG. 2. The three shoes are ar
`ranged in alternately overlapping relation, each having
`one side edge portion 33 which abuts slidably against
`an extension of the working face of an adjacent shoe on
`one side, while the corresponding side edge portion 33
`45
`of the other shoe abuts slidably against an'extension of
`the working face of the ?rst shoe. Thus, all three shoes
`can be moved simultaneously inwardly toward the tube
`axis in mutually sliding, gap~free relation.
`'
`5 Each side edge portion 33 of a shoe that overlaps the
`working face 27 of the adjacent shoe herein is formed
`with an inwardly projecting, longitudinal lip 34 having
`an arcuate inner side of concave curvature constituting
`the curved surface 28 for shaping the curved sections
`of the tube, this surface preferably being concentric
`with the tube and tangent to the working face 27 of the
`shoe on which it is formed, and also tangent to the
`working face 27 of the shoe against which the lip slides.
`Ideally, the arcuate surface might terminate in a knife
`edge at 35, but for the practical purpose of minimizing
`the likelihood of breakage, this edge preferably is
`blunted.
`,
`As shown most clearly in FIGS. 3A and 4, the bevels
`are simply ?at surfaces disposed at suitable forwardly
`and outwardly inclined angles with the axis of the tube,
`for example, ?ve to forty degrees, depending upon the
`desired angle of the transition zone. On one side of
`
`6.
`I each bevel is a ?ared lip 36 constituting an extension of
`the associated lip 34 and having a concave inner side
`which preferably is a section of a cone-and constitutes
`the surface 32 for shaping the tube in the. transition
`zone. The free edge of this lip preferably is blunted for
`durability and isin the same plane as the edge of the lip
`34.
`The actuator of the pointer 10, which may take vari
`ous forms, moves all of the die shoes simultaneously in
`wardly relative to each other toward the axis of the
`tube 12 (which may beeither stationary or movable)
`thereby to close the die 13. During such closing move
`ment, the overlapping side edge portions 33 slide along
`the working faces 27 of the adjacent shoes while the
`working facesthemselves remain parallel to the tube
`axis. Thus, the working faces ?rst are pressed against
`the sides of the tube (three sides ‘as in FIG. 7) in tan
`gent relation therewith along three longitudinal lines
`37, and then begin to ?atten the sides of the tube
`progressively toward the triangular condition shown in
`FIG. 8. Such ?attening is accompanied by initial sink
`ing of thethree bevels 30 into the tube in angularly
`spaced relation around the portion of the tube within
`the ?ared end portion .of the die recess 14 that is
`de?ned by the bevels.
`I
`.
`-
`As closing of the die 13 continues, the tube 12 is
`formed to the shape shown in FIG. 8 with three ?at
`sides 38, and the longitudinal portions of the tube
`between these ?at sides are shaped into arcuate sec
`tions 39 which nest ?rmly against the inner surfaces .28
`of the lips 34. After the die. reaches the‘ condition
`shown in FIG. 8, further inward motion of the shoes
`squeezes the arcuate sections 39 radially inwardly and
`progressively shortens the exposed portions of the
`working faces. The ?at sides 38 of the tube, being con
`?ned and backed against outward bulging, begin to
`buckle inwardly, as shown at 40’ in FIG. 9, and to form
`loops'as shown at 41 in FIG. 10.
`. Apparently because there is effective tangential
`travel of- the working faces 27 as the die 13 is closed,
`the loops 41 thus formed are not directed exactly
`toward the axis of the tube, as might be expected. In
`stead,,as illustrated in FIG. 10, each loop is offset
`slightly from center so that continued crushing of the
`tube results in ?attening of the loops in an offset,
`pinwheel fashion as shown in FIG. 11, thus producing a
`general symmetry or uniformity in the cross-sectional
`con?guration of the point. Closing of the die can be ter
`minated at any selected stage after the generally cylin
`drical point 1 1 has been formed, and, of course, can be
`continued beyond the condition shown in FIG. 11 if a
`denser point is desired. In fact, with suf?cient actuating
`pressure and appropriately formed die shoes, the point
`can be crushed to an essentially solid'rod and even ex
`tended in length.
`The loops 41 shown in FIG. 10 extend forwardly
`beyond the working faces 27 and along the bevels 30,
`while the arcuate sections 39 extend forwardly and
`?are outwardly along the concave surfaces 32 con
`stituting sections of a cone. Thus, each transition con
`volution 31 (FIG. 6) is formed between two .arcuate
`sections of the tube that are controlled by the conical
`surfaces, and it has beenfoundthat a rounded crease
`forms at the bottom of the convolution and spreads
`progressively as the convolution ?ares, being broadly
`
`50
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`Page 7 of 11
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`

`3,695,087
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`8
`the bottom member 18-, thus forcing the right upper ‘die
`shoe 24 downwardly along the right side of the lower
`die shoe 25. As the right shoe slides along the lower
`. shoe, the abutting inclined surfaces 33'and 27 of the
`5
`shoes cooperate to cam the lower shoe to the left, and
`the upwardly- inclined surface 50 of the bottom
`member 18 simultaneously guides the lower shoe up
`wardly and inwardly at a ratedetermined by the slope
`of the surface 50. At the same time, this upward motion
`of the lower shoe is transferred to the lower edge 33 of
`the left shoe 26 through the overlapped sides .of the two
`shoes, and is combined with the downward motion of
`the top member 15 to produce an inward (to the right)
`motion of the left die shoe at a rate determined by the
`slope of the inclined surface 45 and the rate of move
`ment of the left shoe along this surface.
`Accordingly, with properly correlated slopes on the
`various cam surfaces, the three die shoes 24-26 are ‘
`moved simultaneously and at the same rate toward the
`axis of the tube 12. Termination of this closing move~
`ment can be controlled in various ways, for example, by
`one or more limit switches (not shown) actuated in
`response to ‘movement of the die shoes to selected posi- .
`tions, the limit switches preferably being adjustably -
`positioned for selective variation of the point of ter
`mination. The same switching arrangement that ter
`minates the closing stroke also can automatically in~
`itiate the following opening stroke.
`30
`During opening of the die recess 14, the three shoes
`‘24-26 move reversely along the paths followed during
`closing, the right shoe 24 being raised as the top
`member 15 is raised by' the hydraulic cylinder 61, 62,
`thereby permitting the lowershoe 25 .to be returned
`along the surface 50 by the spring 51 and the left shoe
`26 to be lowered along the surface. An additional
`switching arrangement can be provided to terminate
`the opening stroke as the die shoes return to the posi
`tion in FIG. 2. The details of such switching arrange
`ments, including manual or timed automatic actuation,
`are well known in the art and therefore are not
`described indetail herein.
`
`20
`
`25
`
`7
`rounded short of thelarger end of the transition zone
`29. As closing of the die is completed, the part-conical
`‘ surfaces 32 come together into the desired full-conical
`shape to form the transition zone to that shape..The
`closed, conical condition is shown most clearly in FIG.
`3A, and also in FIG. 21 with regard to a four-shoe form
`of the pointer, hereinafter described in detail.
`The-preferred manner of actuation of the pointer 10
`is the cam arrangement-illustrated-in FIGS. 2 and 3
`wherein it will be seen that the upper die ‘shoes 24 and
`26 are arranged generally in the shape of an inverted
`‘*V” ‘with inclined, upwardly facing outer sides 42 and
`43 parallel to the working faces 27 of the shoes and
`nested against similarly inclined, downwardly facing
`‘surfaces 44 and 45'o'n the underside of the top member
`15 of the case. The third die shoe 25 is generally trian
`gular in shape and has an outer side 47 that is inclined
`upwardly and to the left, and the' overlapped side edge
`.33 is-inclined downwardly and to the right beyond the
`overlapping portion of the working face 27 of the shoe
`24. Rollers 48 are disposed between the inclined outer
`‘side 47 and an inclined, parallel upper surface 50 of the
`bottom member 18, thus supporting the lower die shoe
`25 for movement upwardly and to the-left along the
`inclined surface 50 of the bottom member.
`A coiled extension spring. 51 is stretched between
`two pins 52 and 53 respectivelymounted in a recess 54
`in the bottom member 18 and a recess 55 in the lower
`die shoe 25, thus urging the shoe downwardly toward
`the position shown in FIG. 2 and holding it ?rmly
`against the rollers 48; which may be maintained in
`spaced ‘ parallel '
`relation
`by
`rack-and-pinion
`mechanisms 57 at their ends, as shown in FIG. 1. A
`35
`similar spring 58 for holding the upper right die shoe 24
`against the surface 44 is stretched between pins 59 and
`'60 .on the top member 15 and the shoe, although it will
`be seen that this shoe does not move relative to the
`‘ upper member during actuation of the pointer. The
`40
`spring merely holds the die‘ shoe ?rmly-in place against
`the surface 44 and formsa releasable connection
`facilitating changing of the die.
`1
`The die shoe 26 may be‘ similarly spring positioned,
`but preferably is controlled by a hydraulic cylinder
`formed by a blind bore 61 which parallels the inclined
`surface 45 of the top ' member and telescopingly
`receives the lower end portion of a plunger 62 that is
`formed with a longitudinal through passage 63. This
`passage communicates at its lower end with the bore 61
`and at its upper end with a conduit 64 for receiving
`?uid under pressure from an external source (not
`, shown) through a ?tting 65. This cylinder forms, in ef
`fect, a hydraulic spring which returns the shoe 26 and
`the top member l5.to the positions shown in FIG. 2 to
`open the die 13 after each pointing operation.
`'
`‘7 With the ‘foregoing arrangement, the parts are I
`‘disposed in the positions shown in FIG. 2 prior to each
`pointing operation, and a tube 12 may be inserted in
`the open die recess 14 in the manner shown, with suf?
`cient clearance around the tube to permit easy inser
`‘tion. If desired, a tube guide (not shown) may be
`mounted on, or in front of,'the front guide 19 to posi
`tion the tube for the pointing operation.
`With the tube properly positioned, a ram 67 abutting
`against the top member 15 is actuated to force the top
`member and the side plates 17 downwardly relative to
`
`45
`
`FIRST ALTERNATIVE EMBODIMENT (FIGS. I
`
`‘
`
`'
`
`12-19)
`
`It has been stated that at least three die shoes are be
`lieved to be necessary in order to de?ne a gap-free die
`recess capable of being closed around a tube in ac
`cordance with the present invention. It should be
`emphasized, however,’ that the invention is not limited
`to the use of three die shoes, and that, in fact, different
`circumstances may make the use of four or more shoes
`' advantageous.
`55
`Since each die shoe produces one fold or convolu
`tion in the tube in, and adjacent to, the point, changes
`in the number of shoes will result in different numbers
`and angular spacings of the convolutions. With tubes
`having walls with a relatively high thickness-to-diame
`ter ratio, it is relatively difficult to buckle and fold the
`tube wall, so the use of a lesser number of shoes will
`form the folds farther apart, angularly, around the tube
`and insure that the wall sections will buckle inwardly
`from the polygonal stage rather than feeding
`peripherally around the inner surfaces of the die. For
`tubes having walls with a relatively low. thickness-to
`diameter ratio, a greater number of die shoes are used
`
`60
`
`65
`
`Page 8 of 11
`
`

`

`9 .
`to provide better control of the relatively easy-to-fold
`
`tube walls.v -
`
`_
`
`3,695,087
`
`-
`
`IO
`
`15
`
`20
`
`25
`
`35
`
`In the pointer 70 shown in FIGS. 12-14, in, which
`some corresponding, generally similar parts are in
`dicated by corresponding reference ‘numbers it will be
`seen that four die shoes 71-74 are arranged around and
`de?ne the die recess 14, which thus is generally square
`in'cross section when the die is open. As before, these
`die ‘shoes have ?at inner working faces 27 in planes
`parallel to the axis of the tube 12, are arranged in al
`ternately overlapped relation permitting closing move
`ment of the die shoes in the square or rectangular form,
`and ‘have lips 34 with curved inner surfaces 28
`preferably consituting longitudinal sections of a
`cylinder.
`' .In addition, as shown in FIG.>14, each die shoe ‘71-74
`has a bevel 30 from the forward end of the working
`face 27 to the front side of the shoe, and each bevel
`merges smoothly with a part conical surface 32 for
`shaping the transition zone 29- of the tube as the die is
`' closed, forming the full conical surface around the tube
`-as can be seen in the similar form shown in FIG. 21.
`The four die shoes 71-74 of - FIGS. . 12-14 are
`mounted and actuated‘ in substantially the same way as
`the three shoes in FIGS. 1-5, being mounted in a case
`including a ?xed bottom vmember 18, two upstanding
`side plates 17 which in this instance are fastened to the
`side edges of the bottom member, and a top member 15
`which is movable vertically between the side plates. A
`30
`~ ram 67 engages the top member to apply the force
`necessary to push the top. member down and close the‘
`die around the tube 12, and a front plate 75 is bolted to
`the bottom member and the side plates to close the
`front of the case except for an aperture 77 (FIG. 14)
`formed therein to admit the tube