US3729968A

US3729968A - Working of strip metal

Info

Publication number: US3729968A
Authority: US
Inventors: D Norris
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-05
Filing date: 1971-12-22
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01
Also published as: DE2021635C2; IE34704B1; CH532972A; FR2042401A1; NL7006395A; SE380745B; IL34352A0; GB1280331A; DE2021635A1; CA943747A; MTP643B; IE34704L; LU60831A1; FR2042401B1; JPS5019517B1; BE749902A

Abstract

Annular metal rings are manufactured by winding metal strip into a tightly compacted helical coil, cutting the coil, and securing together the ends of the individual rings so formed. Compensation for distortion of the strip produced by winding the strip is made by a die against which the strip being wound is pressed by force applied through the coil.

Description

United States Patent [1 1 Norris [4 1 May 1,1973

[ WORKING OF STRIP METAL [76] Inventor: Douglas C. Norris, 6 Saviles Close,

Eaton Socon, England [22] Filed: Dec. 22, 1971 [21] Appl. No.: 211,005

Related US. Application Data [63] Continuation-impart of Ser. No. 33,856, May 5, 1970, abandoned, which is a continuation-in-part of Ser. No. 832,804, June 12, 1969, abandoned.

[30] Foreign Application Priority Data May 5, 1969 Great Britain ..22,795/69 [52] US. Cl. ..72/129, 72/136, 72/142, 83/5, 83/924, 83/371, 83/364 [51] Int. Cl. ..B2ld 11/06 [58] Field of Search ..10/73, 74, 86 B; 72/136, 167, 142, 129; 83/5, 924, 371, 364;

[ 56] References Cited UNITED STATES PATENTS 368,569 8/1887 Caldwell ..72/136 561,579 6/1896 Gare ..72/142 825,249 7/1906 Stevens ..72/142 744,671 1 H1903 Aiken ..72/142 1,156,458 10/ 191 5 Blanchard ..72/142 Primary Examiner-Lowell A. Larson Attorney-Richard C. Sughrue et al.

[5 7] ABSTRACT Annular metal rings are manufactured by winding metal strip into a tightly compacted helical coil, cutting the coil, and securing together the ends of the individual rings so formed. Compensation for distortion of the strip produced by winding the strip is made by a die against which the strip being wound is pressed by force applied through the coil.

12 Claims, 12 Drawing Figures Patented May 1, 1973 3,729,968

.3 Sheets-Sheet l Patented May 1, 1973 Q s Sheets-Sheet 2 FIG .4.

FIG. 6

Patefited May -1, 1973 1 3,729,968

3 Sheets-Sheet I5 WORKING OF STRIP METAL CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of my application Ser. No. 33,856 filed May th, 1970, which was a continuation-in-part of my application Ser. No. 832,804 filed June 12th, 1969, and both now abandoned.

BACKGROUND OF THE INVENTION This invention relates to the manufacture from metal of annular rings and part-annular components.

Conventionally, annular metal rings, for use as clutch plates and seal rings for example, are stamped out from sheet metal and the metal within the rings is scrapped. If the rings have relatively large inside diameters and the outside diameters are not very much greater, the quantity of metal wasted is much more than that used. Since the monetary return on the metal sent for scrap is very much less than the cost of the raw material, the effective raw material cost of manufacturing rings by the conventional method may be much greater than the cost of the material used in the rings. To reduce the overall cost of manufacturing annular rings it has been proposed for many years to cut such rings from a coil wound from metal rod or strip. However, when an annular ring is formed in this way its outer edge stretches and becomes thinner. Consequently, although the surfaces of the stock from which the ring is formed may be perfectly parallel, the cross-section of the ring has a slight taper and the inner edge has a ripple.

The early US. Pat. No. 561,569issued to T.Gare, on June 9th,! 896, combats this problem in connection with lock-nut manufacture by using a machine adapted to wind stock of tapered cross-section. US. Pat. No. 978,974 issued to .I.Wilson on Dec. th, 1910, repeats this solution in connection with winding steel spring washers. Both patents are concerned with an end product which is of almost square cross-section. Practising these processes requires a two stage operation, namely the rolling of rod to a tapered section and then the winding of the shaped rod in a machine of the type proposed by Gare. To simplify the process other inventors have tried to carry out the shaping operation just before or at the same time as the bending operation takes place. For example, US. Pat. No. 1,107,005 issued to C.White on Aug. 1 lth,l914 proposes using sets of forming rolls upstream of the winding station, and U.S. Pat. No. 1,404,994 issued to A.Moore on Jan. 3lst,l922 proposes the use of sets of forming rolls at the winding station. US. Pat. No. 1,878,233 issued to E.A.Dewald on Sept. 20th,l932 proposes means for gripping opposite surfaces of the strip as bending takes place and squeezing the strip so as to redistribute the metal from the inner edge of the strip. Other prior art suggests the use of a roll against which square-sectioned stock is pressed as it enters the bending station in order to resist the formation of bulges in the stock but without any deliberate re-shaping of the cross-section. Of the prior art referred to hereinabove, only two patents, namely the patents to White and Dewald, are concerned with the winding of relatively thin strip and each inventor requires that the metal or the strip should be soft, to enable it to be shaped by the relatively insignificant pressures which are applied by the machines which they propose. If rings are to be manufactured from ordinary steel strip of any of the grades currently used for seal rings and clutch plates and like items, the pressures which must be applied to carry out the reshaping of the strip is way and above the pressure which it is contemplated should be applied with the machines proposed by White and Dewald, or any of the other prior art machines. For example, mild steel strip may require to be subjected to pressures in excess of fifty tons per square inch. This, I believe, is one reason why such prior art proposals have failed to supplant conventional ring forming methods.

The present invention differs from the prior art in two important respects. Firstly, the shaping of the strip is carried out! by drawing the strip across a stationary drawing face which is profiled to cause a flow of metal towards the 1 radially outer region of the strip: and,secondly, the shaping takes place while the strip is forced against the drawing face by pressure transmitted through a tightly compacted coil. consisting of the previously wound turns. More specifically, the drawing face is positioned so as to prevent the formation of a ripple along the edge of the strip which will become the inner edge of the coil, and to collect and redistribute the metal which would otherwise have formed the ripple. The drawing face is therefore located in a position where it is contacted by the strip just before bending of the latter commences. A stationary drawing face is able to shape the strip better than forming rolls without the effect of increasing the hardness of the strip. The transmission of pressure to the strip against the drawing face by way of the coil has a number of advantages,thus, the pressure applied to the strip against the drawing face can be of any required magnitude,for example,up to 200 tons in a preferred embodiment of machine, such a pressure being in excess of most if not all ordinary requirements;:the strip is drawn over the face by frictional contact with the coil; and the surface in contact with the portion of strip being shaped is continuously being replaced so that there is no risk of this second die face causing wear.

DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of one embodiment of machine for winding coils from strip metal in accordance with the invention,

FIG. 2 is a section taken on the axis of the mandrel of the machine of FIG. 1, omitting the mandrel for clarity, during the winding ofa coil,

FIG. 2A is a similar section ofa machine for winding disked rings,

FIG. 3 illustrates diagrammatically the severing of the coil to separate the turns,

FIGS. 4 and 4A illustrate diagrammatically a system for severing the coil,

FIG. 5 is a perspective view of the tailstock end of a further embodiment of machine,

FIG. 6 shows one embodiment of ring provided by the invention,

FIG. 7 shows the ring of FIG. 6 being welded,

FIG. 8 is a side elevation of a second machine for coiling strip,

FIG. 9 is a view taken on the line 9-9 of FIG. 8, but to a larger scale,

FIG. 10 is a sectional view taken on the line A-B of FIG. 9.

3 DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGS. 8 to l0, a machine for winding steel strip ofa commercially available grade into a helical coil preparatory to cutting the individual turns to form annular rings or part-annular components, comprises a bed 1, a headstock 2 at one end of the bed and a tailstock 7 which is guided for movement along the bed by guideways 24. A hydraulic motor 25 is mounted on the headstock and is operable to rotate a drive plate 26. A tubular extension 27 projects fromdrive plate and has a drive ring 10 at its outer end. The end surface 30 of the drive ring has a slot 11 for receiving and retaining the end-of a length of metal strip to be wound. One edge of the slot stands proud of the other by a distance equal to the thickness of the strip strip and the surface 30 slopes helically from one edge to the other so that a helical coil of strip may be formed against the drive ring. A mandrel 3 extends retractably through the tubular extension 27 and is keyed so as to rotate with the drive ring. The tailstock is linked at 17 to the piston rod 31 of a hydraulic cylinder 14 supported in the headstock and associated with a control system so that movement of the tailstock away from the headstock is resisted by the variable resilient force.

The tailstock supports a housing at the center of which is mounted a die block 4 having a central opening 13 which is dimensioned to receive the mandrel 3. The die block has a pressure face 12 which commences with a substantially linear entry zone 121 and increases in distance from the front face of the support housing 5 through part of one turn of a helix to terminate at an edge 124 which is spaced from the surface at the entry zone by a distance substantially equal to the thickness of the strip to be wound. A strip support 32 is provided immediately below the entry zone so as to provide an edge 33 which supports strip fed to the machine.

The entry zone is shaped to provide a drawing face to force metal of the strip from the inner to the outer side of the mandrel axis N before each segment of the strip reaches the vertical axis V intersecting the die ring axis. The shape of the entry zone is seen more clearly in FIG. where the scale as viewed vertically in the figure is exagerated whereas, as viewed horizontally the scale corresponds to FIG. 9, thus the thickness of the strip entering the zone (i.e. dimension 1:) may be about 0.036 inches whereas the width of the strip (i.e. dimension y) may be about 2 inches.

The entry zone has an initial section 35 which is substantially flat and normal to the block die axis. This section merges into a drawing face 37 which is shaped to produce a flow of metal in the downwards direction as viewed in FIG. 9 as strip is forced across it. As seen in FIG. 10 the drawing face has a surface 36 which extends away from the section 35 at an obtuse angle 38 which is appropriate to the task in hand and merges into the surface 122 which has the correct gradient to cause the rings to lie one against the other as they are formed. The line 39 marking the commencement of the surface 36 of the drawing face extends across the entry zone as seen in FIG. 9 either diagonally, at the angle indicated, or at another angle, depending upon the material.

In carrying out the winding operation, the end of a strip of metal is bent over at right angles to its length and inserted in the slot 11, which is located at the 6 oclock" position. The tailstock is moved hard up against the face of the drive ring and the hydraulic system set to provide the required resistance to movement. The motor is then started so that strip is drawn along the entry zone and around the arcuate zone of the pressure face so as to build up a series of helical turns, the tailstock being forced back against the resilient resistance. Because the coil is under pressure, the strip is drawn into the coil by frictional pressure transmitted through the turns of the coil. The segment of strip at any instant in the entry zone is pressed against the die face by the length of the strip instantaneously leaving the pressure face across edge 124. The action of bending, although taking place downstream of the line V shown in FIG. 9, tends to cause a ripple to build up on the upper edge of the strip upstream of this line. The drawing face is so shaped and the pressure applied such that the ripple is prevented from forming and the surplus metal thereby made available on the upper side of the neutral axis is made to flow across to the lower side of the neutral axis.

The shape of the drawing face and the angle at which it extends across the entry zone depend upon the thickness of the strip, its hardness, malleability and other characteristics so that the exact shape must be determined afresh for any given product.

When the coil has been fully wound, the drive motor is stopped, the mandrel retracted into the extension piece 27, and the coil removed and severed to separate the individual turns as diagrammatically illustrated in FIG. 3. 1f annular rings are to be made, the ends of each individual turn are secured together.

A particularly convenient system for accurately severing the rings will now be described. A hydraulic cylinder 18 is mounted to one side of the housing 5. The piston rod of the cylinder carries at its end a bracket equipped with a scoring tool 19 which, when the cylinder is pressurized, traverses the length of the completed stationary coil while it is still compacted and scores an axially extending groove in the outer surface of the coil. The cylinder 14 is then vented, the mandrel retracted and the coil removed. The slackened coil thus forms a loose helix having a series of equally spaced triangular notches along one edge, each notch having sides about 0.01 inch long. The loosened strip is then passed lengthwise through a quillotine shown in FIGS. 4 and 4A. The guillotine has a fixed blade 202 and a movable blade 201 operated by a fluid logic circuit 203. The circuit includes a sensor 21 having a transmitter tube 211 associated with one jaw 201 and a receiver tube 212 associated with the other jaw 202. A jet of air constantly issues from tube 211 and in the absense of strip S enters tube 212, the jet intersecting the line of cut of the guillotine. As the loosened metal strip S is fed lengthwise through the guillotine in the direction of arrow D, the edge of the strip blocks transmission of the jet. As each notch enters the line of cut, the path of the jet is unblocked and the entry of the jet into the tube 212 triggers the logic circuit to operate pneumatic cylinder 204 which displaces the blade 201 to thereby sever the strip at the location of the notch. There is a risk that irregular cuts may be made if the strip is not in its proper position in the guillotine. To monitor the proper position of the strip, a further pair of sensors 22, one sensor on each side of the sensor 21, are therefore provided, and each of the

sensors

20, 22,

22 occupies a position on a curve having a radius equal to that to which the strip is wound. The logic circuit provides that the guillotine is capable of operating only if both of the sensors 22 are blocked by the strip and the sensor 20 unblocked.

FIGS. 1 and 2 illustrate a further embodiment of a machine for winding strip metal in which the same references are used to designate the parts corresponding to the parts shown in FIGS. 8 to 10 and wherein the die block has a channel 123 for the strip, the radially inner edge of the channel being formed by the mandrel when the latter is in position. A pin 1 1, instead of a slot, is used to secure the strip to the drive ring 10 and rolls 3 guide the strip S into the entry zone of the die channel. As can be seen the depth of the channel decreases from maximum depth in the entry zone to zero depth at 124 where the strip rides out onto the end surface of the die block. As seen in FIG. 2, a pair of hydraulic cylinders 14 mounted behind the tailstock apply the requisite resistance to movement of the tailstock. A further embodiment, shown in FIG. 5, includes an extended entry zone and a front plate 40 to apply pressure to the strip before it enters the coil in cases where a ripple is found to build up a considerable distance ahead of the point where the bend takes place.

The ends of the ring can either be welded together, as shown in FIGS. 6 and 7, or keyed together by a lug on one end entering a cut-out in the other.

Obviously, modifications may be made within the spirit of the invention. Thus, for example, varying widths and thicknesses of strip may be processed, and coils of different diameters may be wound. Also employing by a conical drive ring I and complementary die, the invention may be applied to the manufacture of dished rings. In addition, the invention may be employed to form a ring having a cross section which makes it suitable for use, after a subsequent pressing operation, as an impeller for use in hydraulic transmission units. Such items are also to be regarded as annular rings. Further, although it is preferred for the die to be component of the machine which moves axially, it is feasible for the die to remain stationary and for the coil to build up away from the die.

Although the invention is primarily intended for the production of rings with parallel front and back surfaces, by an accurate control of the amount of metal redistributed, it will be understood that the die may over or under compensate to thereby produce a ring with a cross section other than rectangular.

I claim:

1. A machine for winding metal strip for use in the manufacture of annular rings and part-annular components, said machine comprising a frame, strip endretaining means supported by said frame for rotation about an axis, drive means for driving said strip endretaining means in rotation about said axis, a mandrel arranged with its axis coincident with the axis of rotation of the strip end-retaining means, support means mounting a pressure face in opposed relationship to said strip end-retaining means, and means for resiliently resisting relative movement apart of said strip end-retaining means and pressure face support means; said pressure face including an entry section leading in to an arcuate section which extends around said axis through part of one turn ofa helix the pitch of which is substantially equal to the thickness of the strip to be coiled, said pressure face including a sizing zone profiled to effect flow of metal from one side to the other of the neutral axis of strip drawn across said sizing zone under pressure transmitted through a coil built up on said mandrel from said means resisting relative movement apart of said strip-end retaining means and said pressure face support means.

2. A machine as claimed in claim 1, wherein said strip end-retaining means is a drive ring having a radial slot in a support surface which forms a turn of a helix, the pitch of which corresponds to that of the arcuate section of said pressure face.

3. A machine as claimed in claim 1, wherein said sizing zone is disposed in the entry section of said pressure face.

4. A machine as claimed in claim. 1, wherein said sizing zone includes a drawing face having an upstream surface meeting a downstream surface in an obtuse angle so as to provide a space for trapping and redistributing the metal of the strip.

5. A machine as claimed in claim 1, including a pair of opposed surfaces defining a path for strip about to enter said entry zone, said surface being adapted to prevent the formation of a ripple in strip ahead of said entry zone.

6. A machine as claimed in claim 1, including a scoring tool movable in the direction axially of said mandrel so as to score a groove in a coil supported on said mandrel.

7. A machineas claimed in claim 2, wherein, for the manufacture of dished rings, the drive ring has a conical face and the arcuate section of the pressure face has a complementary conical surface.

8. In a process for the manufacture of annular metal rings, in which thin strip metal is wound edgewise into a helical coil and compensation is made for distortion of the strip produced by the winding thereof, said coil being severed to separate the turns, the improvement consisting of compacting said coil under axial pressure so as to trap a portion of the strip between a stationary die and a previously wound section of the strip, preventing the formation of a ripple along one edge of the said portion of strip, and flowing the metal which would otherwise form said ripple across said strip towards the other edge thereof.

9. A process for the manufacture of annular metal rings comprising: connecting one end of a length of thin metal strip to a drive ring so that said length extends substantially tangentially of a mandrel disposed coaxially of said drive ring, rotating the drive ring to wind said strip edgewise into a helical coil on said mandrel, causing at least the portion of strip about to be wound into said coil to contact a stationary die face, applying pressure axially of said coil to compact said coil and to cause the said portion of strip to be gripped tightly between said die face and a portion of strip already wound into said coil, a flow of metal being produced in said portion as it is drawn across the die face, said flow of metal being such as to compensate for distortion of the strip produced by edgewise bending, whereby the faces of the strip wound to form turns of the coil are substantially parallel, relaxing said pressure, removing said coil from the mandrel, severing the coil to separate the individual turns, and securing together the ends of each of at least some of said severed turns 10. In a process for the manufacture of annuiar rings and part-annular components, the steps of:

providing a continuous length of metal strip, the width of said strip being much greater than its thickness,

providing a guide path for said strip, said guide path having a substantially straight entry section followed by an arcuate section which extends through part of one turn ofa helix about an axis.,

causing one end of said strip to follow a path about said axis so as to draw said strip continuously along said entry section and said arcuate section and form a turn of a helix, the strip bending about a first edge as it enters the arcuate section,

continuing to draw strip through the entry and arcuate sections of said path so as to form successive turns ofa helix and thereby build up a helical coil,

applying pressure to said coil during said last-mentioned step so as to compact the coil in the axial direction,

causing displacement of metal from the region of said strip adjacent said first edge to a region adjacent the opposite edge as said strip passes through a sizing zone between a stationary surface and a continuously changing face provided by previously wound strip, said displacement resulting from a change in profile of the guide path within said sizing zone and taking place against reaction provided by said continuously changing face, said displacement compensating at least partially for distortion of the cross-section of the strip during bending,

discontinuing the rotation of said coil, relaxing said pressure, and severing the coil to separate the turns thereof.

11. A process as claimed in claim 10, wherein said sizing zone is disposed in said entry section, strip therein being shaped against a reaction surface constituted by the portion of strip instantaneously leaving the end of the arcuate section so as to ride over the strip in the entry section.

12. A process as claimed in claim 10, wherein, when winding of the coil has been completed, rotation of the coil is stopped and the stationary coil is scored along a line parallel to the coil axis to produce a series of equally spaced notches in the outer edge of the strip, the coil is allowed to slacken and the strip fed lengthwise through a station at which each notch is sensed and the strip severed in response "to such sensing.

Claims

1. A machine for winding metal strip for use in the manufacture of annular rings and part-annular components, said machine comprising a frame, strip end-retaining means supported by said frame for rotation about an axis, drive means for driving said strip end-retaining means in rotation about said axis, a mandrel arranged with its axis coincident with the axis of rotation of the strip end-retaining means, support means mounting a pressure face in opposed relationship to said strip end-retaining means, and means for resiliently resisting relative movement apart of said strip end-retaining means and pressure face support means; said pressure face including an entry section leading in to an arcuate section which extends around said axis through part of one turn of a helix the pitch of which is substantially equal to the thickness of the strip to be coiled, said pressure face including a sizing zone profiled to effect flow of metal from one side to the other of the neutral axis of strip drawn across said sizing zone under pressure transmitted through a coil built up on said mandrel from said means resisting relative movement apart of said strip-end retaining means and said pressure face support means.

4. A machine as claimed in claim 1, wherein said sizing zone includes a drawing face having an upstream surface meeting a downstream surface in an obtuse angle so as to provide a space for trapping and redistributing the metal of the strip.

7. A machine as claimed in claim 2, wherein, for the manufacture of dished rings, the drive ring has a conical face and the arcuate section of the pressure face has a complementary conical surface.

9. A process for the manufacture of annular metal rings comprising: connecting one end of a length of thin metal strip to a drive ring so that said length extends substantially tangentially of a mandrel disposed coaxially of said drive ring, rotating the drive ring to wind said strip edgewise into a helical coil on said mandrel, causing at least the portion of strip about to be wound into said coil to contact a stationary die face, applying pressure axially of said coil to compact said coil and to cause the said portion of strip to be gripped tightly between said die face and a portion of strip already wound into said coil, a flow of metal being produced in said portion as it is drawn across the die face, said flow of metal being such as to compensate for distortion of the strip produced by edgewise bending, whereby the faces of the strip wound to form turns of the coil are substantially parallel, relaxing said pressure, removing said coil from the mandrel, severing the coil to separate the individual turns, and securing together the ends of each of at least some of said severed turns

10. In a process for the manufacture of annular rings and part-annular components, the steps of: providing a continuous length of metal strip, the width of said strip being much greater than its thickness, providing a guide path for said strip, said guide path having a substantially straight entry section followed by an arcuate section which extends through part of one turn of a helix about an axis., causing one end of said strip to follow a path about said axis so as to draw said strip continuously along said entry section and said arcuate section and form a turn of a helix, the strip bending about a first edge as it enters the arcuate section, continuing to draw strip through the entry and arcuate sections of said path so as to form successive turns of a helix and thereby build up a helical coil, applying pressure to said coil during said last-mentioned step so as to compact the coil in the axial direction, causing displacement of metal from the region of said strip adjacent said first edge to a region adjacent the opposite edge as said strip passes through a sizing zone between a stationary surface and a continuously changing face provided by previously wound strip, said displacement resulting from a change in profile of the guide path within said sizing zone and taking place against reaction provided by said continuously changing face, said displacement compensating at least partially for distortion of the cross-section of the strip during bending, discontinuing the rotation of said coil, relaxing said pressure, and severing the coil to separate the turns thereof.

12. A process as claimed in claim 10, wherein, when winding of the coil has been completed, rotation of the coil is stopped and the stationary coil is scored along a line parallel to the coil axis to produce a series of equally spaced notches in the outer edge of the strip, the coil is allowed to slacken and the strip fed lengthwise through a station at which each notch is sensed and the strip severed in response to such sensing.