METHOD AND APPARATUS FOR SIMULTANEOUSLY FORMING FOUR METAL ROUNDS

Abstract: This invention relates to method and apparatus for simultaneously forming four metal rounds and includes disclosure of two pair of forming rollers (140, 142), a pre-slitter roller pair (144) and two pairs of slitting rollers (160, 162), the dimensioning of the ridges and grooves of which, in combination, serve to separate an entering bar (150) into four strands of substantially equal area (150a, 150b, 150c, 150d) for simultaneous forming into metal rounds.

Description: -1- vr Title: METHOD AND APPARATUS FOR SIMULTANEOUSLY FORMING FOUR METAL ROUNDS SPECIFICATION Field of the Invention This invention relates to the forming of small 5 diameter metal rounds, such as reinforcing bar rounds. More specifically, this invention relates to methods and apparatus for simultaneously forming by rolling four rounds of uniform size. 10 βackgrpμnd of tfte Invention The forming of small diameter rounds from larger bars is known in the milling art. Generally, a large bar is successively passed through a series of rollers that reduce the cross sectional area of the bar and, 15 through a number of intermediate steps, eventually forms the desired shape. Because the amount of the reduction of the cross sectional area on each pass through the rollers is limited, the smaller the cross sectional area of final product, the larger the number 20 of roller passes, machinery and production floor space required. The simultaneous forming of multiple rounds significantly reduces the above-stated problems because the reduction in total cross sectional area is 25 considerably less, therefore, fewer intermediate steps are required and the speed and length of the end product is reduced. It is known in the art to simultaneously produce two uniform metal rounds and three uniform metal -2- rounds. The simultaneous production-of three rounds is described in U.S. Patent No. 4,357,819. The additional problems involved in producing four rounds simultaneously from one bar are significant. The problems include maintaining the uniformity of the cross sectional areas of the strands as well as avoiding the cobbling of the strands during the slitting process. Other considerations include the resistance produced when separating the strands, which resistance can result in excessive heat, lower separating speeds and lower efficiency. filiimnΛT-Y τ f the Invention This invention discloses apparatus for use in simultaneously forming four metal rounds. The apparatus includes a irst pair and a second pair of forming rollers. These forming rollers are connected in series to sequentially pass a bar. Each pair has an adjustable separation distance. Grooves are formed in the surfaces of the first and second roller pairs. The grooves are dimensioned in combination such that the bar, at the completion of the second pass, is formed into four portions of substantially equal areas. The apparatus includes a pair of pre-εlitter rollers connected downstream from the forming roller pairs. The pre-slitter rollers have an adjustable separation distance. At least one of the pair of pre- slitter rollers has two central grooves that define a free space. This pre-slitter roller also has three serial ridges. The grooves and the ridges of the pre- slitter roller, or rollers, are dimensioned in combination with the grooves of the first and second forming roller pairs. The dimensioning in combination functions to form a bar comprised of four serial strands of substantially equal cross sectional area separated by thin connecting portions. In the preferred embodiment each roller of the first roller pair has a groove oriented with respect to the entering bar such that each groove forms an end portion of the bar. The separation distance between the surfaces of the first roller pair determine the width of the bar. The width of the groove in each roller of the first pair determines the cross-sectional height of an end portion of the bar. In the preferred embodiment the rollers of the second pair are oriented with respect to the entering bar such that the separation distance between the roller surfaces determines the height of the central portion of the bar. In addition, in the preferred embodiment, the rollers of the second pair have ridges for forming the bar into four portions separated by thick connecting portions. In the preferred embodiment the ridges of the pre- slitter roller have outside and inside slope angles of approximately 30°. The invention discloses further apparatus for use in simultaneously forming metal rounds from a bar guided to the apparatus, the bar being comprised of four serial strands, two outside and two middle, separated by thin connecting portions. The further apparatus comprises a first pair of slitter rollers, each roller having a first and second ridge located to correspond with a thin portion connecting an outside strand to a middle strand. The ridges have an outside slope angle greater than the inside slope angle of the corresponding portion of the outside strand. The apparatus also includes means serially connected downstream of the first pair of slitter rollers for separating the two middle strands. In the preferred embodiment the outside slope angles of the ridges of the first slitter rollers exceed the inside slope angles of the corresponding portions of the outside strands by approximately 22°. Further, it has been found effective if the outside slope angle of the ridges of the first slitter rollers are approximately 52°. The apparatus may further include inside slope angles for each ridge of the first slitter rollers that are less than the outside slope angle of the corresponding middle strand. It has been found effective if the inside slope angles of the first slitter rollers are approximately 25°. In the preferred embodiment the means for separating the two middle strands is comprised of a slitter roller pair wherein at least one roller has a ridge located to correspond to the thin connecting portion between the two metal strands. The slope angles of the second slitter roller ridge are greater than the corresponding inside slope angles of the middle strands. It has been found effective if the inside slope angles of the ridge exceed the corresponding inside slope angles of the middle strands by approximately 5 β . Thirty-five degrees (35 β ) has been found to be an effective slope angle for the ridge of the second slitter roller. The invention discloses a method for forming a bar to be slit and simultaneously formed into four metal rounds that comprises adjusting the separation distance between a first pair of forming rollers and between a second pair of forming rollers. The method includes passing a bar by the first of rollers to form a bar of fixed cross-sectional width and fixed cross-sectional height over end portions of the bar, and passing the bar by the second pair of rollers to form a bar of fixed cross-sectional height over central portions of the bar. The method includes, subsequent to the above steps, passing the bar by a pair of pre-slitter rollers. The pre-slitter rollers have three ridges for forming four serial strands of approximately equal cross-sectional area separated by thin connected portions. The invention also discloses a method of slitting a bar comprised of four serial strands, two outside and two middle, of approximately equal cross-sectional area separated by thin connecting portions. The method comprises passing the bar by a first pair of slitter rollers, each having two ridges with interfering outside slope angles and noninterfering inside slope angles. Such passing of the bar serves to separate each outside strand from the two middle strands by applying a lateral force with portions of the outside of the ridge to portions of the inside surface of an outside strand. At the same time, significant lateral force is not applied with the inside surface of a ridge to the outside surface of a middle strand. The method includes subsequently separating the two metal strands. Brief Description of the Drawinσs Fig. 1 comprises a schematic plan view of a series of connected forming and slitting rollers of the preferred embodiment. Fig. 1A comprises a schematic elevational view of a roller stand. Figs. 2A through 2G illustrate the bar subsequent to the forming passes, the slitting passes and further forming passes. Fig. 3A is an elevational view of one of a pair of forming rollers. Fig. 3B is an elevational view of one of a pair of forming rollers. Fig. 4 is an elevational view of one of a pair of pre-slitter rollers. Fig. 5 is an elevational view of a slitter roller. Fig. 5A is an illustrative view of the interaction of a bar of formed into strands with a slitter roller. Fig. 5B is an illustrative closeup of a detail of the interaction of the ridge of a slitter roller with the sides of the strands of a bar. Fig. 6 is a view of a single ridge slitter roller. Fig. 6A is a view of a bar separated into four strands connected by thin connecting portions. Description of the Preferred Embodiment A conventional roller stand S is schematically shown in Fig. 1A. An elevational view of a roller pair that would be utilized toward the end of the process of simultaneously forming four metal rounds is illustrated. As shown, two cylindrical rollers 154 are mounted within frame 99. The longitudinal axes of the rollers are shown horizontal to the floor. The two rollers are further illustrated as being placed vertically parallel to each other, one on top of the other. This presumption of a horizontal and vertical alignment of the rollers has been adopted herein for convenience. Those skilled in the art would understand that the roller stand could be rotated such that the aforementioned vertical and horizontal directions could assume other directions. When rollers 154 of Fig. 1A are rotated in the direction indicated by the arrows, the bar of metal, now separated into four strands, will be drawn through the rollers and would move in a direction out of, and perpendicular to, the surface of the paper. The bar, or strands, may be regarded aε having a length, a width and a height. The width and the height are cross sectional dimensions. Rollers 154 predominately form and affect the cross sectional dimensions of the bar or strands. In roller stand S, the axes of the rollers, indicated by dashed lines 166 and 168, are usually adjustable with respect to each other. This permits adjustment of the separation distance between the surfaces of the rollers. The adjustability of the axes is indicated by the arrows 171 associated with axes 166 and 168. The separation distance between the rollers affects the form of the bar and the cross sectional area of the strands created. The ability to vertically adjust also permits compensation for wear of the roller surfaces. The cylindrical surfaces of the rollers are conventionally sculpted, or dimensioned, to contain circumferential grooves 170 and ridges 172. A ridge, as the word is used herein, may present a flat top surface, as illustrated in Fig. 1A, or may rise to a nearly pointed or a pointed surface, as in roller 144 of Fig. 1. The grooves and ridges serve to form the bar in a pass. The cross sectional area of the bar will exhibit a configuration conforming or semi- conforming to the cross sectional area between the rollers. The degree of confirmation depends upon the design of the rollers and the extent to which they contain free space in or around the grooves. The grooves are designed with respect to the anticipated cross sectional area of the incoming bar. The separation distance of the rollers may be adjusted such that the metal of the bar is forced to flow into, conform to, and fill all of the space of the groove. Excess metal, in such case, may move during the pass -8- toward the free space at the side of the rollers. The grooves may also be designed, in conjunction with the separation distance, to a depth that defines a free space therein. The free space serves to substantially eliminate the flow of metal from a groove during a pass. The preferred embodiment illustrated herein assumes that the grooves and ridges of a roller pair are sculpted identically onto the face of each roller to form a matched pair. However, it will be appreciated by those skilled in the art that the invention may function if the rollers of a roller pair are designed with nonmatching grooves and/or ridges. The term "slope angle" is used herein. "Slope angle" as it is used indicates the angle between the "vertical" and a tangent drawn to a point on a ridge or a strand. A "vertical" is perpendicular to the axis of the roller. Reference is made to "inside" and "outside" "slope angles" of ridges and strands. When this reference is used, it is to be understood that, with respect to a strand, only the slope angles of "central portions" of sides of a strand are indicated. When the "slope angle" of a ridge of the roller is referred to, it is to be understood that only the slope angles of portions of the ridge that "correspond to" central portions of a corresponding side of a strand are indicated. For instance, in Fig.4 the area designated 90 illustrates the portions of ridges 146, 147 and 148 that correspond to the slope angles of central portions of the strands formed by the ridges. In Fig. 5B the areas designated 165 and 166 comprise illustrative central portions of sides of a strand. The slope angle of the strands in their "central portions" is referred to because it is against these -9- side walls of the strands that the slitter rollers, to be discussed below, either do or do not "interfere", or do or do not exert a lateral force. As discussed below, a lateral force can be exerted by ridge of a slitter roller. When this ridge exerts the lateral force, it is said that the ridge has a slope angle, at least in portions corresponding to central portions of the strand, that would "interfere" with the slope angle of the strand. The actual slope angle in "non-central" portions where, for instance, strand 150b or strand 150c, as illustrated in Fig. 5B, intersect the thin connecting portion separating the two strands, is not so significant. It is the slope angle along the "central portions" of the side slope of the strand that is important. These central portions either will receive a lateral force from the interference of the slitter roller slope angle. For instance, as illustrated in Fig. 5B, which is included for illustrative purposes, not as part of the preferred embodiment, one ridge of slitter roller 160 is shown inserted within or between the side walls of strand 150c and 150d to the point where it touches or virtually touches the thin connecting portion. It may be that where the peak of the ridge on slitter roller 160 meets or almost meets the thin connecting portion, the slope angle of the ridge is in fact less than the slope angle of strands 15Od. As illustrated in Fig. 5B, the slope of the inside central portion of the wall of strand 150d is defined by the angle between tangent 112 drawn to that inside strand wall and vertical 122. This angle is illustrated as angle 106 in Fig. 5B. The slope of the corresponding central portion of the ridge of the slitter 160 is illustrated by angle 104 drawn between vertical 122 and tangent 119 drawn at a "central portion" of the outside of the ridge of slitter roller 160. Similarly, when measuring the relative slope angles of the inside surface of the slitter ridge vis¬ a-vis the outside surface of strand 150c, the relevant central portion of strand 150c is denominated by numeral 166 in Fig. 5B. Tangent 117 drawn to a point on a central portion of strand 150c makes angle 100 with vertical 122. Tangent 121 drawn to a corresponding central portion of the ridge of slitter roller 160 makes angle 102 with vertical 122. The relative sizing of angles 104 and 106 and angles 100 and 102 determine whether the ridge of the slitter roller interferes, or does not interfere, with the side wall of the strand. As schematically shown in Fig. 1, a metal bar 150 moves in the direction of arrow 180 past five roller stands. First rollers 140 are shown installed with their axis of rotation in the vertical direction. Since the schematic view is presented as from above and the following four roller pairs are illustrated as installed vertically, one above the other, only one roller of the subsequent four pairs, roller 142, roller 144, roller 160 and roller 162, is shown. For the same reason rollers 140 have a central groove 139 that is not shown in Fig. 1 but is shown in Fig. 3A. As bar 150 proceeds through the series of roller stands in the direction of arrow 180, it takes on new cross sectional shapes as a function of the shape of the grooves and the ridges found in the surface of the rollers, and, to some extent, of the separation distance between the rollers in a pair. Rollers 160 and 162 are slitter rollers. As illustrated in Fig. 1, roller 160 slits bar 150 into a central portion and two outside strands, 150a and I50d. Slitter roller 162 slits the central portion of bar 150 into strands 150b and 150c. After the four separated strands emerge from slitter roller 162, they will be formed into metal rounds by a further series of forming rollers, as is known in the art. Such forming rollers are not illustrated in Fig. 1. As mentioned above, the dimensioning of the grooves and ridges on the roller surfaces, as well as the adjustment of the separation distance between the rollers of a pair, determines the effect of the grooves and ridges have upon the metal bar passing the stand. Such effect is illustrated for the preferred embodiment in Figs. 2A through 2G. Fig. 2A illustrates rollers 140 installed with their axes of rotation in the vertical direction. Fig. 3A illustrates one forming roller 140 in greater detail. The separation distance between the roller 140 surfaces is established such that one central groove 139 in each roller conforms each end portion of bar 150 to the dimensions of the groove. The adjustment of the separation distance between rollers 140 determines, the width of the bar. The height of groove 139 determines the height of each end portion of bar 150 as it passes rollers 140. Free space 141 between the rollers accommodates the flow of any excess metal from the ends of the bar into the central portion of the bar. Rollers 142 of Fig. 2B are illustrated installed with their axes of rotation in the horizontal direction, as are all succeeding roller pairs. Fig. 3B illustrates one roller 142 in greater detail. Rollers 142 have sculpted in their surface a series of grooves 143a and flat ridges 143. The separation distance between rollers 142 is adjusted such that the metal of the bar fills the space in the central portion of the rollers between the roller surfaces. Thus, the height and shape of at least the central portion of the bar is formed by rollers 142. Excess metal is accommodated by being permitted to flow to the outside space between the two rollers. Those skilled in the art will appreciate that bar 150 is guided between roller pairs 140, 142, 144 and the slitter rollers. Thus, the grooves and ridges of one roller pair can be aligned in combination with the grooves and ridges of a prior roller pair. They can be dimensioned in combination to create an effect in sequence. Both rollers 144 in the preferred embodiment contain three ridges 146, 147 and 148. Although, it is preferred that both rollers contain the ridges, one roller with the ridges could suffice. Fig. 4 illustrates one roller 144 in greater detail. Ridges 146, 147 and 148 are dimensioned to establish four strands in bar 150, namely 150a, 150b, 150c and 150d. The four strands are connected by thin connecting portions. Strands 150a and 150d are outside strands. Strands 150b and 150c are middle strands. Ridges 146, 147 and 148 not only establish thin connecting portions between four serial strands but also establish certain slope angles that the strands assume. Roller pair 144 also contains two central grooves 145 that provide for free space 145a above middle strands 150b and 150c formed in grooves 145. The free space permits the forming of the thin connecting portions by the rollers of pair 144 without redistributing metal from the middle strands to the outside strands. The free space accommodates a certain variance in cross sectional area of middle strands 150b and 150c. Slitter rollers 160, one of which is illustrated in Fig. 5, will slit the bar 150 comprised of four serial strands 150a, 150b, 150c and 150d connected by thin connecting portions, as illustrated in Fig. 2C, into a middle portion comprised of strands 150b and 150c still connected by a thin connecting portion and separate outside strands 150a and 150d, as illustrated in Fig. 2D. Slitter rollers 162, one of which is illustrated in Fig. 6, separates middle section 150b and 150c connected by thin connecting portions, as illustrated in Fig. 2D, into two separate strands 150b and 150c as illustrated in Fig. 2E. Figs. 2F and 2G illustrate a subsequent working of the four separated strands 150a, 150b, 150c and 150d by rollers by 152 and rollers 154 into four uniform rounds. This subsequent simultaneous working, illustrated in Figs. 2F and 2G, is understood by those skilled in the art. Hence, the details of such working will not be further discussed. In a review of Figs. 2A and 2B, it can be seen that bar 150 as it emerges from rollers 140 has a predetermined width and the height of its end portion is determined. Bar 150 as it emerges from rollers 142 of Fig. 2B has the height of its central portion determined. In the preferred embodiment, bar 150 as it emerges from rollers 142 contains in fact four portions separated by thick connecting portions, the thick connecting portions being formed by ridges 143. Bar 150, after completing the pass of rollers 140 and 142, is known to be divided, by one who is informed of the dimensions of rollers 140 and 142, into four portions of substantially equal area. One problem to be solved in the simultaneous forming of four metal rounds is maintaining the uniformity of the cross sectional area of the four -14- metal rounds. That is, the diameter of the rounds should con orm to specifications within a certain tolerance. The words "substantially equal area" are used herein to indicate that the cross sectional area of the four portions would, if formed into rounds, have diameters that conformed to the specifications within the given tolerances. In the preferred embodiment, the passes are arranged such that the bar passes first through rollers 140 and then past rollers 142. Reversing the progress through the first two pair of forming rollers, i.e. putting rollers 140 downstream of rollers 142, should yield a somewhat equivalent result. That is, bar 150 subsequent to both passes could be divided into four portions of substantially equal cross sectional area. As discussed above, the first two passes by the forming rollers conform entering bar 150 to four portions of substantially equal cross sectional areas. Pre-slitter rollers 144 separate the bar into four strands separated by thin connecting portions. The substantially equal cross sectional area is maintained. Pre-slitter rollers 144 also establish slope angles of the strand. In the preferred embodiment, the two outside strands are first slit from the two middle strands by slitter rollers 160. Subsequently, the two middle strands are slit by slitter rollers 162. This is illustrated in Fig. 1 and Figs. 2d and 2e. The slitting is performed by applying a lateral horizontal force to the walls of the strands, effecting a tearing along the thin connecting portions. The lateral force is delivered by the interference of the slope angle of a side of a ridge of the slitter roller with the slope angle of a corresponding side of a strand. In the process of separating off the two outside strands with εlitter rollers 160, ridge angle 118 is designed in combination with the ridge angles 146 and 148 of pre-slitter rollers 144 such that the slitter roller ridge angle is greater than the strand 150a or 150d inside slope angle. In the preferred embodiment the difference in the angle 118 and the angles 146 or 148 is approximately 22°. Angle 118 is preferably approximately 52° while angles 146 and 148 are approximately 30°. In the preferred embodiment, the inside slope angles of the ridges of slitter roller 160, that is, the angle formed by side 120, is less than the outside slope angle of strands 150b and 150c. The difference is approximately 5°. In the preferred embodiment the outside slope angle of strands 150b and 150c are approximately 30° while the inside slope angles of the ridges of roller 160 are approximately 25°. In such a fashion, lateral separating forces are applied to strands 150a and 150d without applying a friction force to the two captive inside strands 150b and 150c. Although the side walls of the ridges of slitter roller 160, as illustrated in Fig. 5 and 5A, are shown approximately straight, i.e. side walls 118 and 120, it should be understood that the side walls of the ridge of slitter roller 160 could assume a continuously curved configuration. They should be designed in conformity with a similarly curved configuration given to strands 150a, 150b, 150c and 150d, at least in their central portions, by the ridges 146, 147 and 148 of pre-slitter rollers 144. As illustrated in Figs. 6 and 6A, inside edge 134 of the ridge of second slitter roller 162 forms angle 138 with a vertical 132. The inside slope angles of strands 150b and 150c make angle 97 between tangents 98 and vertical 112. In the preferred embodiment, angles 37 -16- 138 are greater than angles 97. In fact, angles 138 exceed angles 97 by 5°. In the preferred embodiment, the inside slope angle 97 is essentially 30° and the ridge outside slope angles are essentially 35°. With such arrangement, second slitter roller 162 applies a lateral force and separates by tearing strand 150b from strand 150c. The foregoing disclosure and description of the invention are illustrative and explanatory thereof. Various changes in the size, shape and materials as well as the details of the illustrated construction may be made without departing from the spirit of the invention.

Claims: I CLAIM; 1. Apparatus for use in simultaneously forming four metal rounds comprising: a first pair and a second pair of forming rollers connected in series to sequentially pass a bar, each pair having an adjustable separation distance; grooves in the surfaces of the first and second roller pairs, dimensioned in combination to form the bar at the completion of the second pass into four portions of substantially equal cross sectional area; and a pair of pre-slitter rollers connected downstream of the first and second roller pairs, the pair having an adjustable separation distance and wherein at least one pre-slitter roller has two central grooves defining a free space and three serial ridges; the pre-slitter grooves and pre-slitter ridges dimensioned in combination with the grooves of the first and second forming roller pairs to form a bar comprised of four serial strands of substantially equal cross sectional area separated by thin connecting portions. 2. The apparatus of claim 1 wherein each roller of the first roller pair has a groove oriented with respect to the entering bar such that each groove forms an end portion of the bar, the separation distance between the surfaces of the first roller pair determining the width of the bar and the width of the groove in each roller of the first pair determining the cross sectional height of an end portion of the bar. 3. The apparatus of claim 1 wherein the rollers of the second pair are oriented with respect to the entering bar such that the separation distance between the roller sur aces determine the height of the central portion of the bar. 4. The apparatus of claim 3 wherein the rollers of the second pair have ridges for forming the bar into four portions separated by thick connecting portions. 5. The apparatus of claim 1 wherein the two outside ridges of the pre-slitter roller have outside and inside slope angles of approximately 30°. 6. The apparatus of claim 1 wherein the inside ridge of the pre-slitter roller has slope angles of approximately 30°. 7. Apparatus for use in simultaneously forming metal rounds from a bar guided to the apparatus, the bar being comprised of four serial strands, two outside and two middle, separated by thin connecting portions, the apparatus comprising: a first pair of slitter rollers, a first ridge and a second ridge on each roller of the first pair, each ridge located to correspond with a thin portion connecting an outside strand to a middle strand and having an outside slope angle greater than the inside slope angle of the corresponding portion of the outside strand; and means serially connected downstream of the first pair of slitter rollers for separating the two middle strands. 8. The apparatus of claim 7 wherein the outside slope angles of the ridges of the first slitter rollers exceed the inside slope angles of the corresponding portions of the outside strands by approximately 22°. 9. The apparatus of claim 7 wherein the outside slope angles of the ridges of the first slitter rollers are approximately 52°. 10. The apparatus of claim 7 wherein the inside slope angle of each ridge of the first slitter rollers is less than the outside slope angle of the corresponding portions of the middle strand. 11. The apparatus of claim 10 wherein the inside slope angles of the ridges of the first slitter rollers are approximately 25°. 12. The apparatus of claim 7 wherein the means for separating the two middle strands is comprised of a second slitter roller pair, at least one roller having a ridge located to correspond to the thin connecting portion between the two middle strands, the slope angles of the second slitter roller ridge, being greater than the corresponding inside slope angle of the middle strand. 13. The apparatus of claim 12 wherein the slope angles of the ridge exceed the corresponding inside slope angles of middle strands by approximately 5°. 14. The apparatus of claim 13 wherein the slope angles of the ridge are approximately 35°. 15. A method for forming a bar to be slit and simultaneously formed into four metal rounds, comprising: adjusting the separation distance between a first pair of forming rollers and between a second pair of forming rollers; 7 -20- passing a bar by the first pair of rollers to form a bar of fixed cross sectional width and ' fixed cross sectional height over end portions of the bar; passing a bar by the second pair of rollers to form a bar of fixed cross sectional height over a central portion of the bar; and subsequent to the above steps, passing the bar by a pair of pre-slitter rollers having three ridges to form four serial strands of approximately equal cross sectional area separated by thin connecting portions. 16. A method for slitting a bar comprised of four serial strands, two outside and two middle, of approximately equal cross sectional area separated by thin connecting portions, comprising: passing the bar by a first pair of slitter rollers, each having two ridges with interfering outside slope angles and noninterfering inside slope angles, thereby separating each outside strand from the two middle strands by applying a lateral force with portions of the outside surf ce of the ridge to portions of the inside surface of an outside strand without applying significant lateral force with the inside surface of a ridge to the outside surface of a middle strand; and subsequently separating the two middle strands.

Inventors: ELLEY DAYTON W, MATSUO GIICHI, RAINS JIMMY JERAL, SAKAI AKIRA, ELLEY, DAYTON, W., MATSUO, GIICHI, RAINS, JIMMY, JERAL, SAKAI, AKIRA
Applicants: STRUCTURAL METALS INC, STRUCTURAL METALS, INC.
Application year: 1992
Main classification: B21B1
IPC codes: B21B1