US2469223A - Apparatus for use in making precoiled helical fins - Google Patents

Description

May 3, i949. E. BRUEGGER 6 APPARATUS FOR USE IN MAKING PRECOILED HELICAL FINS Original Filed Sept. 8, 1944 2 Sheets-Sheet 2 INVENTQR 677N557 BFUfGGEf? PM, ivwunm wm HIS ATTORNEY Patented May 3, 1949 APPARATUS FOR USE IN MAKING PRE- COILED HELICAL FINS Ernest Bruegger, Massillon, Ohio, assignor to The Griscom-Russell Company, New York, N. Y., a

corporation of Delaware Original application September 8, 1944, Serial No. 553,153, now Patent No. 2,437,500, dated March Divided and this application March 15, 1947, Serial No. 734,961

4 Claims.

This invention relates to the manufacture of fins and more particularly concerns an improved machine for use in making helical fins useful in the manufacture of cylindrical elements from or to which heat is transferred, such as cylinders for internal compustion engines. This application is a division of my co-pending application Serial No. 553,153, filed September 8, 1944 (Patent No. 2,437,500, granted March 9, 1948).

Many devices and processes require the rapid transmission of considerable quantities of heat from or to a tubular or cylindrical body. For example, cylinders of internal combustion engines employed in aircraft must be cooled to prevent failure of these or other parts of the engine in operation. The power output of such engines for a given piston displacement has recently been greatly increased by the use of high compression ratios and new fuels, and this increase necessitates an increase in the heat radiating capacity of the cylinders to prevent overheating.

Heat radiating fins for air-cooled engine cylinders have been produced by casting or machining them directly on and integral with the cylinder Wall or a, sleeve attached to the cylinder. These procedures are expensive, provide but a limited increase in the heat dissipating surface and in general produce cylinders which cannot be safely operated at power outputs obtainable from engines employing liquid cooled cylinders of the same piston displacement.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide an improved apparatus which produces helically coiled fins for engine cylinders or like cylindrical components, whereby cylinders with greatly extended heat radiating surfaces may be produced. Another object of the invention is to provide an apparatus which produces pre-coiled fin structures rapidly and inexpensively without wasting metal. A further object of the invention is to provide apparatus of the type described which is simple in design, easily constructed and readily adjustable and operable to produce a highly satisfactory product even in the hands of relatively unskilled workers.

The fin preferably produced by my improved apparatus is an edgewise wound helical ribbon having a substantially L-shaped foot along its inner edge. The bottom of this foot engages the cylindrical surface to which the fin is secured, and the end of the foot engages the face of an adjacent turn of the fin and thereby provides the proper spacing between the fin turns. I

have found that attempts to bend the L-shaped foot along the inner edge of the fin to final form while bending a straight metallic ribbon into a helical coil result in buckling or other improper or irregular bending of the fin metal, and that with such procedure it is difiicult to control the width and thickness of the foot element. I have devised a method and apparatus in which a straight metallic ribbon is first bent edgewise into a helical coil While its inner edge portion is displaced at an angle. of less than 90 to the remainder of the fin, and in which the pre-colledfin thus produced is then continuously bent along its inner edge to finish the foot bend so as to dispose the foot normal to the radially extending fin. My improved method forms the subject matter of my oo-pending application Serial No. 734,960, filed March 15, 1947 and the apparatus for bending the straight ribbon edgewise into a helical coil and simultaneously displacing its inner edge at an angle of less than 90 to the plane of the remainder of the fin as described and claimed in my above noted application Serial No. 553,153, filed September 8, 1944.

The apparatus of the present invention comprises a heading machine which continuously forms the angula'rly displaced inner edge portion of a pre-coiled ribbon into an L-shaped foot.

In describing the invention in detail, reference will be made to the accompanying drawings in which 3A typical; embodiment of my improved beading machine has been illustrated. In the drawings;

Fig. 1 is a side elevation of a beading machine embodying the invention taken from the side from which a precoiled ribbon approaches the machine;

Fig. 2 is an elevation taken from the opposite side showing the machine illustrated in Fig. 7;

Fig. 3 is a plan view of the beading machine together with means for guiding a pre-coiled ribbon toward and away from the machine;

Fig. 4 is a sectional view on an enlarged scale taken along the line 4-4 of Fig. 1 and showing the bead forming rollers of the heading machine; and

Fig. 5 is an enlarged view of a few turns of the pre-coiled ribbon on which the beading machine operates.

The disclosed embodiment of my improved beading machine comprises generally two pairs of cooperating rollers 80, 8|, 82 and 83 having:

conical surfaces between which a, pre-coiled ribbon 15 progresses, together with two foot forming rollers 84 and 85 which respectively ers 99 and 9i are so ca n thgflth flcomfl surfaces are parallel and .are spaced apart a distance substantially equal to the thickness or the fin ribbon 19, the arrangement being such that the fin is tightly gripped and advanced by these rollers when they rotate. The periphery a pre-coiled ribbon of this nature is disclosed and claimed in my co-pending application Serial No. 134,960, filed March 15, 1947.

As shown in Figs. 1, 2 and 3, a vertically extending frame plate 99 is mounted on a horizontal base 9'! and carries a Journal bracket 99in which a drive shaft 99 is journaled. The shaft 99 may be driven by any suitable. means through a pulley 90, and carries a beveled pinion 9i at its inner end. Two angularly disposed shafts 92 and 93 are journaled in brackets 94 and 95 secured to one side of the frame plate 99 as shown in Fi 1. The shafts 92 and 93 are convergent,-the upper shaft 92 slanting downward and inward toward the plane of the plate 99 and the lower shaft 93 slanting upward and inward so that the continuations of the axes of these shafts would intersect at or approximately at the center of rotation of the pre-coiled ribbon 15 passing through the machine. The shafts 92 and 93 are driven in the same direction by beveled gears 99 and 91 respectively fixed to the outer ends of the shaft and meshing with the beveled pinion 9|.

Two shafts I and I0| are journaled in brackets I02 and I03 secured to the opposite side of the frame plate 99 from the shafts 92 and 93 (Fig. 2). The shafts I00 and MI converge as do the shafts 92 and 93, the projected axes of all of these shafts intersecting at or substantially at the center of the axis of rotation of the precoiled ribbon 15. Intermeshing beveled gears I04 and I05 are respectively secured to the shafts 92 and I00 adjacent the inner edge of the plate 96, and similar Intermeshing gears I09 and I0! are respectively fixed to the shaft 93 and IN.

With this arrangement, the shafts I00 and IM are both driven in the same direction which is opposite to the direction of rotation of the shafts 92 and 93.

The inner ends of the shafts 92 and 93 carry frusto-conical ribbon gripping rollers 90 and 92 of identical design, and similar rollers 9I and 93 are similarly fixed to the inner ends of the respective shafts I00 and IN. The rollers 90 and 9I are illustrated in enlarged section in Fig. 4, and since the rollers 92 and 93 are respectively identical with the rollers 80 and 9I they will not be separately described. As shown in Fig. 4, the conical slope of the roller faces is such that projections of elements of these faces pass through the point where the projected axes of the shafts 92 and I00 intersect substantially at the axis of rotation of the coiled fin ribbon I5. The roller 90 has a bead I09 forming a shoulder adjacent its larger end, and carries a forming plate I09 fixed to its smaller end by a stud H0 and a nut III, The marginal portion of the end face of the plate I09 has formed therein a circular recess forming a surface H2 disposed at right angles to elements of the conical surface of the roller. The roller 9I carries a forming plate H3 fixed to its smaller end by a stud H4 and a nut H5. The peripheral surfaces of the plates H3 and I09 are shaped to be aligned with and to form continuations of the conical surfaces of the respective rollers 9| and 90. 'The end face of the forming plate H3 is dished so as to present a marginal portion disposed at right angles to the conical surface of the roller 9i. The rollof theforming plate m on the roller an ex-[ j tends beyond'the surface H2 in the recess of the plate I09 on the roller by a distance substan-,

tially equal to the thickness of the fin metal.

A cylindrical roller 94 is rotatably supported Y 1 on a pivot H! with its axis substantially horizontal and at right angles to'elements of the-57' conical roller surfaces and its periphery engaging the marginal end face of the forming plate. H3 and extending over the surface H2 'offthe forming plate I09. The roller pivot III is-carshown in Fig. 4. A cylindrical roller 95,. identical with the roller 94 is pivotally mounted tobear against the ends of the conical rollers 92 and 99 in the same manner as that described above in connection with the roller 99. slotted guide roller I20 is rotatably journaled in a bracket I2I fixed to the plate 99 and is disposed above and substantially in vertical alignment with the space between the rollers 90 and ti. A similar peripherally slotted guide roller I22 is rotatably mounted in a bracket I23 below and substantially aligned with the space between the lower conical rollers 92 and 93.

Suitable means may be provided for guiding the pre-coiled ribbon or fin I5 to the beading mechanism and for leading the finished fin away from that mechanism after the forming operation performed therein is completed. As illustrated in Fig. 3, the pre-coiled fin delivery guide may comprise a drum I25 rotatably mounted on a shaft I29 supported by a bracket I21, fixed to the base 91. The drum is of slightly smaller diameter than the internal diameter of the precoiled fin I5, and may be of any desired length. The mechanism for receiving the finished coiled fin may comprise a similar drum I29 rotatably carried by a shaft I29 supported in a bracket I30 fixed to the base 91. The drums I25 and I29 may be of the same diameter and are of such size that the coiled ribbon readily clears these surfaces and slips on and off the drums without binding. The drums I25 and I29 are each disposed at a small angle to the axis of the fin turn passing between the beading machine rollers, so that adjacent turns are held out of contact with the parts of the machine, as shown in Fig. 3.

In the operation of the beading machine in completing the method of the invention, a section of the ribbon I5 that has been pre-coiled and carries the angularly bent inner edge portion, I3I is placed on the guiding drum I25 and its leading end is started downward through the peripheral slot of the guide roller I20 and between the rollers 90 and 9|. The four conical rollers 90. 9|, 92 and 93 are rotated in the directions indicated by the arrows in Figs. 1 and 2, and the ribbon I9 is successively drawn between the conical surfaces of the cooperating pairs of rollers 90, 9|, 92 and 93. The ribbon is tightly gripped by these rollers and as it passes between the first pair 90 and 9i, the periphery of the cylindrical roller 99 bends the inner edge of the ribbon down against the end surface H2carried 1 by the roller 90 so that an L-shaped foot I32 lying at right angles to the body of the fin A peripherally 1 ribbon is formed. This bending action is illustrated in Figs. 1 and 4. The second pair of conical rollers 82 and 83 and a cooperating cylindrical roller 85 complete the bending operation and hold the foot and ribbon in proper bent relation. If desired, the clearance between the lower cylindrical roller 85 and the cooperating end faces on the conical rollers 82 and 83 may be less than that between the corresponding parts of the upper rollers 80,,8I and 84, so that the bending of the foot I32 to final form is accomplished in two steps. Where the composition of the fin metal or the dimensions of the fin ribbon permit, one of the sets of foot forming rollers may be omitted. During the bending operation, the shoulders formed by the beads I08 at the larger ends of the rollers 80 and 82 engage the outer edge of the fin ribbon and so limit its movement outwardly parallel to the conical roller surfaces. This insures a uniformly bent foot I32 of the desired dimensions. The ribbon is guided below the bending rollers by the guide roller I22.

The forming surfaces of the ribbon beading machines are preferably formed of hardened and ground steel of high strength and quality. These surfaces include the forming plates I09 and H3 and rollers 84 and 85 in the beading machine.

I claim:

1. In apparatus for forming an L-shaped foot along the inner edge of an edgewise wound helically coiled metallic ribbon, in combination, a pair of frusto-conical rollers, means for rotatably mounting said rollers with their conical surfaces parallel and closely adjacent each other at one point in their rotation, a rotary member having a cylindrical surface closely adjacent the smaller end faces of said rollers and extending across the space between said rollers at said closely adjacent point, means for rotating said rollers at the same speed and in opposite directions 9. peripherally extending shoulder projecting outward from the conical work engaging surface of one of said rollers and means for guiding an edgewise wound helically coiled metallic ribbon between said rollers with its inner edge portion protruding beyond the smaller end faces of said rollers whereby said edge portion is bent laterally by said cylindrical surface.

2. In apparatus for forming an L-shaped foot along the inner edge of an edgewise wound helically coiled metallic ribbon, in combination, a pair of frusto-conical rollers, one roller of said pair having a. forming surface on its smaller end face disposed normal to its conical surface, means for rotatably mounting said rollers with their conical surfacesparallel and closely adjacent each other at one point in their rotation and their smaller end faces in substantial alignment, a rotary member having a cylindrical surface parallel to and closely adjacent said forming surface on the end face of one of said rollers and extending across the space between said rollers at said closely adjacent point, means for rotating said rollers at the same speed and in opposite directions and means for guiding an edgewise wound helically coiled metallic ribbon between said rollers with its inner edge portion protruding beyond the edge of said forming surface whereby said edge portion is bent laterally over said forming surface by said cylindrical surface of the rotary member as the ribbon is drawn between said conical rollers. I

3. In apparatus for forming an L-shaped foot along the inner edge of an edgewise wound helically coiled metallic ribbon, in combination, a pair of frusto-conical rollers, means for rotatably mounting said rollers with their conical surfaces parallel and closely adjacent each other at one point in their rotation and their smaller end faces in substantial alignment, a peripherally extending shoulder on one of said conical rollers projecting outward from the work engaging surface of said roller adjacent the larger end thereof, a rotary member having a cylindrical surface closely adjacent the smaller end faces of said rollers and extending across the space between said rollers at said closely adjacent point, means for rotating said rollers at the same speed and in opposite directions and means for guiding an edgewise wound helically coiled metallic ribbon between said rollers with its inner edge portion protruding beyond the smaller end faces of said rollers and its outer edge abutting said peripherally extending shoulder whereby said edge portion is bent laterally by said cylindrical surface. 4. In apparatus for forming a foot along the inner edge of an edgewise wound helically coiled metallic ribbon, in combination, a supporting plate, a pair of shafts respectively rotatably supported on opposite sides of said plate with their axes converging toward a common point in the plane of said plate beyond one edge thereof, a pair of frusto-conical rollers respectively fixed to said shafts beyond said edge of said plate with their conical surfaces parallel and closely adjacent each other and their smaller ends substantially in alignment, a cylindrical roller rotatably supported on an axis substantially normal to the plane of said plate with the cylindrical surface of said roller adjacent the margins of 'the outer end faces of said pair of rollers at and adjacent the point where their conical surfaces most closely approach each other, a peripherally extending shoulder projecting outward from the conical work engaging surface of one of said rollers and means for rotating said frustoconical rollers in opposite directions.

ERNEST BRUEGGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,364,736 McGlone et al. Dec. 12, 1944 FOREIGN PATENTS Number Country Date 16,638 Great Britain 1901

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