US2847055A - Apparatus for forming and spirally winding a fin strip on an advancing tube - Google Patents

Description

g- 12, 1958 w. F. MATHENY sun. I

APPARATUS F0 FORMING AND SPIRALLY WINDING A FIN RIP ON AN ADVANCING TUBE Filed Jan; 6, 1955 4 Sheets-$heet 1 INVENTORS WILLIAM E MAT HE N Y WILLIAM E HA T HE N Y JR.

ATTORNEY w. F, MATHENY ETAL 2,847,055 APPARATUS FOR FORMING AND SPIRALLY WINDING A FIN STRIP ON AN ADVANCING TUBE Filed Jan. 6, 1955 4 Sheets-Sheet 2 Aug. 12, 1958 4 f 49 f I 3 a7 22 6 63 50 2 28 as 23 2/ 97 as 54 45 I6 9o-- 56 I as 59 INVENTOIRS WILLIAM E MATHENY WILL/AMEMATHENYJ/i'.

ATTORNEY Aug. 12, 1958 w. F. MATHENY ETAL 2,847,055

APPARATUS FOR FORMING AND SPIRAL-LY WINDING A FIN STRIP ON AN ADVANCING TUBE Filed Jan. 6, 1955 4 Sheets-Sheet :5

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INVENTORS ATTORNEY w. F. MATHENY ETAL 2,847,055 APPARATUS FoR FORMING AND SPIRALLY WINDING A FIN STRIP ON AN ADVANCING TUBE Filed Jan. 6, 1955 4 Sheets-Sheet 4 Alig. 12, 1958 FIG/0 INVENTORS WILLIAM E MATHEIVY WILL/AME MAT/IE'NYJR.

ATTORNEY United States Patent APPARATUS FOR FORMING AND SPIRALLY WJIISIEING A FIN STRIP ON AN ADVANCING William F. Matheny and William F. Matheny, Jr.,

Tulsa, Okla.

Application January 6, 1955, Serial No. 480,114 '10 Claims. (CI. 15.3-64.5)

This invention relates to apparatus for forming and shaping metal strips into edge wound spiral coils having integral flanges at their inner edges and simultaneously applying the helixes to longitudinally advancing, rotating tubes for use in the manufacture of heat exchange equipment and the like.

More particularly the invention consists in new and useful improvements in a method and apparatus for manufacturing finned tubing for heat exchangers, wherein a strip of flat metal is continuously fed first through an edge forming device adapted to initially provide a longitudinally extending angular flange along one edge of the strip and thence between two fin forming rolls designed to flatten and stretch the opposite or non-flanged edge of the strip while simultaneously presenting the strip to the periphery of a longitudinally advancing, rotating tube.

An object of the invention is to provide apparatus of this character having guide means associated with the fin forming rolls and adapted to present the successive convolutions of the coiling fins, to the supporting tube or core, in a non-radial plane which intersects the periphery of the tube so that the flanged edge of the strip contacts the periphery of the tube under a slight radial deforming pressure which in effect, causes the edge of the fin strip to flow onto the tube, as it is Wound on the tube, whereby the convolutions of the coil are caused to firmly grip the tube and are maintained in place without the use of solder or other securing medium.

Another object of the invention is to provide a finned tube forming machine which is highly adjustable to faciliate and control the action of the forming rolls and the angle of presentation of the strip to the tubes.

A further object of the invention is to provide finned tube forming apparatus designed both for speed of operation and ease of adjustment and manipulation.

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Figure l is a perspective view from one side of the machine.

Figure 2 is a generally similar view in side elevation.

Figure 3 is an enlarged detail illustrating the preferred form of edge fianging device for the strip.

Figure 4 is a sectional detail of the fin forming and Wrapping rolls.

Figure 5 is an end elevational view as seen from the left side of Figure 2 with the strip guide assembly omitted.

Figure 6 is an elevational view of the main forming roll mounting plate.

Figure 7 is a front elevation of the adjustable strip feeding assembly.

Figure 8 is a sectional view of the same, taken on line 8-8 of Figure 7.

Figure 9 is a transverse sectional view through a tube in the course of being wrapped and swedged, and

Figure 10 is an enlarged sectional view through a finned tube, taken on line 1010 of Figure 9.

In the drawings, 10 represents a horizontal machine bed having a platform 11 at one end. The platform 11 has welded thereon an upstanding frame or support 12 which may be formed of a pair of transversely extending, side plates 13 and 14 having an end plate 15 welded between the vertical edges of the side plates at one end of the frame. The edges of the side plates 13 and 14 at the opposite end of the frame are welded to a main supporting plate 16 which as seen in Figures 1 and 2, extends vertically beyond the frame 12 and laterally to one side thereof. The bottom edges of all of the plates 13, 14, 15 and 16 are welded to the platform 11 to form a rigid supporting structure for the various parts of the apparatus, as will hereinafter appear.

Each of the side plates 13 and 14 is provided with openings to receive a hollow shaft 17 rotatably supported by aligned bearings 18 and 19, secured to the side plates 13 and 14 respectively. A drive pulley 20 runs on a bearing which is pressed on shaft 17 and suitably secured to the pulley, a gear 20 being fixed to one side of the pulley to drive the sun gear 20 of a system of planetary gears hereinafter referred to. The pulley 20 is driven by a belt 21 running from a source of motive power (not shown). The opposite end of the hollow shaft 17 carries a forming roll 22 (Figs. 2 and 4) having a beveled nose 23 which as will later appear, is adapted to cooperate with a second angularly disposed forming roll or wheel 24, in forming and applying a continuous strip of metal to a length of tubing in the fabrication of finned tubes. The forming roll 22 is longitudinally recessed as at 25 from one end, to receive the end of the hollow shaft 17 and a set screw 26 may be provided for firmly securing the roll 22 to the shaft 17, so as to rotate therewith, as will be seen from Figure 4.

The inner end of the forming roll 22 abuts the annular face of bearing 18 which serves the dual purpose of. a rotary bearing for the hollow shaft 17 and an end thrust bearing for the forming roll 22.

An axial opening 27 is provided in the nose of the forming roll 22 to receive the tube 28 which forms the core of the finned tubing being fabricated, so that the annular bevelled nose 23 guides and supports the rotating and advancing tube 28 which is projected through the control bore of the hollow shaft 17. Any suitable means may be employed for rotating and advancing the tube 28 such as shown at 29 in Figure 1. The details of the mechanism 29 are not important to the present invention but it will be understood that a main drive pulley 30, driven by a belt 31, running from a source of motive power (not shown), and operated through some such mechanism as a train of planetary gears, may be employed for this purpose. One form of mechanism for accomplishing this purpose is shown in the copending application of W. F. Matheny, Serial No. 343,944, filed March 23, 1953, and issued September 18, 1956 as Patent No. 2,763,364.

The complementary forming wheel 24 is carried at one end of a shaft 32 rotatably supported in bearings 33- 3 vertical=edge-, by -meansofashaft 36 welded to the edge of the plate 35 and projecting vertically beyondthe upper and lower extremities thereof, where it is rotatably embraced by bearings 37 and 38, bolted to the fixed supporting plate 16- of the main supporting frame'12; As seen in Figure 2, where only the bearing 37 is shown,

thefixedlpl'ate- 16'-is slotted as at39' toreceive the bearing bolts-40,- whereby-the bear-ing 37is'adjustable-laterally in-aplaneaparall'el to the plate-'16. This same arrangement is provided for-the lower 'bearing'38 andthe bearings 37-and= 38- are preferably of' the universal type to provide forminute adjustment of the angular position of the-forming wheel 24' with respectto the forming nose 23, by. manipulation ofthe-bearings 37 and" 38, to change'the angle-of the-axis ofthe shaft36' with respect to the axis of the hollow shaft '17- and the forming nose 28. 'Tofacilitate the adjustment of the shaft 36 and bearings 37' and 38, a set screw arrangement 41, fixed to"one-end of the housingof bearing 37, as at-42, passes through a lug 43 secured to the plate '16.' Lock nuts 44'- retain the setscrew 41' in adjusted position.

The hinged plate 35 carrying the forming wheel 24 and its shaft-32, is adjusted by the means 'justdescribed, to regulate the angle of contact'of" the periphery of the wheel 24 with the-nose 23; of'the forming roll 22, so that asthe ribbon- 45- passesbetween the two forming elements, the degree of; deformation of the strip can b'epredetermined. In other words, as will later appear, it is' desirable to subject the outer edge of the fin strip 45 "toa deforming or flattening pressure as it passes be tween the forming elements, so as to stretch the outer edge and cause the strip to courve around the axis of the tube28 in the form of a helix. Thus, the angle of contact between the periphery of the forming wheel 24 and the nose 23--is' such that the periphery of said wheel 24' lies more closely to the outer edge of the frustoconical nose 23, than to the inner edge thereof; Obviously, by increasing the proximity of'the adjacent peripheriesof the forming elements toward the outer extremity of-the'nose'23, the resulting curve or curling of the finis rend'eredmore acute to determine the ultimate shape'of the ribbon as it is presented to the tube 28, and wrapped thereon.

After this angle of contact has been set, the hinged plate 35is maintained'in locked position by a lock bolt 46 which extends through a fixed lug 47, attached to the edge of'the plate 35, with its other'end engaging a lug 48 fixed to the plate 15 'of" the supporting frame 12. The lock bolt.46 is threaded .to receive a nut 49 by means ofwhich the pressure of the forming wheel 24 against the forming nose 23, may be governed. Obviously, this hinge. arrangement also permits the plate 35 and the elements supportedthereby, to be retracted from the tubing being worked upon.

The metal strip 45 is fed from a reel. (not shown) and before entering between the forming elements 22 and 24, is. preformed'with a longitudinal flange or substantially right angular leg along one edge so as. to provide a base for supporting the fin on the tube 28. The preforming mechanism consists ofa pair of complementary guide rolls 50 and 51, respectively mounted on shafts 52Iand 53, rotatably supported in bearings. 54-and 55. The bearings54 andv 55- are bolted to the front plate 56 of a bracket 57, bolted to the. plate 15 of frame 12. as at 58' in Figure 2. A slot arrangement59v cooperates with the bolts 58 to permit the. adjustmentv of the bracket 57 to align the preforming mechanism 5051.with the strip feeding ,guide to be described.

Although various forms. of. preforming. mechanisms may be employed, the arrangement shown. in Figure 3 has proven satisfactory. Hereit will be seen that the main roll 50.isprovided with aperipheral recess 60 of a. transversedimension to receive the peripheryof the complementary roll 51. The latter is provided with an annular recessv 61 at itsjlower'edge, shaped. to accommodate a radial inclined ridge 62 at one side of the recess 60 in the roll 50, with sufficient clearance therebetween to permit the lower edge of the strip 45 to be bent at an angle into the recess 61, thus forming a foot or base flange 63, along the lower edge of the strip 45 as the strip leaves the preforming rolls. It will be seen in Fig. 3 that the width of the recess 60 is the same as that of the unbent strip 45 and there is just sufiicient clearance between the lateral margins of the recess and the lateral edges of the roll 51 to receive the latter with a running fit. Thus, the roll 51 is kept vertically centered in recess 60 of roll 50, to prevent the strip from being cut as the flange 63 is being turned. The inclined ridge 62 facilitates the bending operation by making it more gradual.

Turning now to the strip feeding assembly shown in detail in Figures 7 and 8, it will be seen that a guide plate 64 forms the means for presenting. the strip 45 to the forming elements 22-24, after leaving thepreforming rolls 5051 which are located anterior to the feeding device. The guide plate 64 consists of an elongated plate having an arcuate edge 65 on one side bounded by a pair of parallel spaced guide flanges 66 between which the strip 45 passes over the arcuate surface. The feeding end ofthe plate 64 terminates in a reduced tapering nose 67'which forms a continuation of the arcuate edge 65 and is adapted to be positioned so as to properly direct the strip 45 between the forming elements 22 and 24.

It is important to the proper operation of this ap paratus, that the guide plate 64 be capable of adjustment in three different planes. In other words, it must be adjustable in a substantially vertical plane toward and away from the axis of the tube. 28 on which the strip is being wound, to control the elevation of the feeding nose 67 with respect to the tube 28. It must be rotatably adjustable about a substantially vertical axis to control the distance of the nose 67 from the tube 28 and it must be rotatably adjustable about a horizontal axis to regulate the angle of presentation of the strip 45 to the tube 28. This latter adjustment is to facilitate the proper feeding of the strip 45 onto the tube 28 in a non-radial plane which intersects the periphery of the tube sov that the flanged edge 63 of the strip contacts the periphery of the tube under a slight radial deforming. pressure which as previously stated, causes the edge of the fin strip to flow on to the tube.

This triple adjustment is accomplished bymounting the strip feeding assembly on a supporting bar 68, slidably mounted in a guide block 69 which is welded to the supporting plate 35 as will be seen in Figures 1 and 2. The supporting bar 68 is adjustable longitudinally, by means of a screw threaded member 70 secured to the upper end ofthe bar and projecting through a bracket 71 welded to and projecting laterally from the plate 35 and after the proper longitudinal adjustment is made, lock bolts 72 and 73 are screwed into engagement with the intervening bracket 71.

The lower end of the supporting bar 68 carries an intermediate connecting link 74 which is offset and pivotally mounted on one side of the bar 68, by a horizontal pivot 75 and extends downwardly into abutting relation with a mounting strip 76 which,.together with the guide plate 64 is pivotally mounted on the lower end of the link 74 by a vertical pivot bolt 77 which extends through both the plate 64 and the strip 76 and into the lower end of the link 74, as seen in Figure 7. A lock screw 78 extending through the plate 64 and into the strip 76 prevents rotary movement of the latter relative with the plate 64.

Adjustment of'the guide assembly about the horizontal axis 75 is accomplished by means of two opposed adjusting screws 79 extending through complementary threaded ears 80 welded to opposite sides of the supporting bar 68, with their inner ends in abutting relation to an intervening lug 81, formed integrally with and projecting upwardly from the link 74. Thus, by manipu= lating the adjusting screws 79 to force the lug 81 either in one direction or the other, the link 74 and the assembly suspended therefrom, is caused to describe an are about the axis 75 to either elevate or lower the nose 67 of the guide plate 64.

A generally similar arrangement is employed for affecting the adjustment of the feeding assembly about the vertical axis 77. As seen in Figure 8, a pair of adjusting screws 82 are supported in opposed relation by a pair of spaced ears 83 welded to opposite sides of the link 74. The inner ends of the screws 82 abut an upstanding lug 84 which is welded to the upper face of the strip 76 and is interposed between the screws 82. Thus, by manipulating the screws 82, the lug 84, the strip 76 and the guide plate 64 are rotated about the axis 77 to control the proximity of the nose 67 with respect to the tube 28.

With the guide plate 64 and its nose 67 properly adjusted, the fin strip 45, with its preformed base flange 63, is fed between the forming roll 22 and forming wheel 24, with the flanged edge 63 advancing into engagement with the tube 28 in a non-radial plane which intersects the periphery of the tube 28 as shown in Figure 9. The action of the forming roll and wheel flattens and stretches the outer edge 85 of the strip 45, causing the strip to coil about the tube 28 as the opposite flanged edge 63 of the strip is being slightly radially deformed and caused to flow on to the tube 28 which is continuously rotating and advancing through the hollow shaft 17 carrying the nose roll 22. The result of this operation is a tight binding vof the flanged edge 63 of the strip on to the tube 28 which avoids the necessity of soldering or other securing medium.

However, in order to provide a more effective gripping action and to produce a more finished product, it is desirable to employ a swedging roll which engages the base flange 63 of the advancing convolutions of the coil and presses it firmly into engagement with the tube 28. This swedging roll consists of a pair of parallel discs 86 spaced on a horizontal axle 87 a sufficient distance to accommodate the fin strip 45. The axle 87 is rotatably mounted in a bearing 88 carried at the upper end of a vertical rod 89, which is reciprocably mounted in a support 90 secured to and projecting upwardly from the platform 11, as seen in Figures 2 and 5. A longitudinal slot 91 in the periphery of the rod 89 engages a key within the support 90 to prevent rotation of the rod 89 and displacement of the swedging rolls 86.

The swedging roll 86 is maintained under a spring tension in its engagement with the fin tube and is retractable from the latter by means of a releasable mechanism shown in Figures 2 and 5. A pair of spaced cross arms 92 are pivotally mounted at one end as at 93, on an intervening vertical leg 94, said cross arms having pivoted between their opposite ends a latch member 95 having a handle 96. A second vertical leg 97 also extending from the platform 11, has a notch 98 for engagement by the latch 95. A grip 99 is fixed to the end of the cross arms 92 of the assembly for elevating the arms into locked position. The swedging roll supporting rod 89 extends between the spaced cross arms 92 and has fixed thereto an abutment 100 which is also secured to the undersides of the cross arms 92. Between the abutment 100 and a collar 101, spaced upwardly on the rod 89, is a coil spring 102 which, when the cross arms 92 are in their upper or locked position, causes a spring tension on the rod 89, forcing the same upwardly and with it the swedging roll 96. When it is desired to release the swedging roll from the tube 28, the operator trips the handle 96 upwardly, releasing the latch 95 from the notch 98 which permits the cross arms 92 and with them the rod 89 and swedging roll 86, to be lowered. The elements are returned to operative position by simply lifting the grip 99 until the latch 95 engages the notch 98.

It will thus be seen that in operation, as the constantly rotating and advancing tube 28 emerges from the bore of the forming roll 22, the preflanged strip 45 is presented to the periphery of the tube and between the periphery of the forming Wheel and the nose 23 of the forming roll. The upper edge of the strip is flattened and stretched to form a coil about the tube 28 and as previously explained, the flanged edge of the strip being presented in a nonradial plane which intersects the periphery of the tube, it is deformed by the tube and caused to firmly grip the tube during its advance. The flanged edge is then swedged on to the tube by the swedging rolls 86 to progressively complete the formation and wrapping of the convolutions of the coiled fin tube. As a result of this operation there is provided a very rigid fin tube structure wherein the base of the fins is firmly supported all along the tube without the need of additional securing means such as solder, etc.

By means of the triple adjusting mechanism for the feeding plate 64, the most minute adjustment is made possible to facilitate the use of different materials and to regulate the pitch of the convolutions of the coiled fin.

It is to be noted that the present invention is primarily designed for the manufacture of flat or smooth helical finned tubing, as distinguished from the corrugated types and the relationship of the forming wheel to the forming nose is such as to enable the simultaneous forming and winding of a minute fin on extremely small tubing. Considerable difliculty has been encountered in the past, in the manufacture of finned tubing of small diameter such as is required in the fabrication of automotive radiators and the like. employing a hollow guide shaft having protruding therefrom a substantially frusto-conical smooth forming nose with a coaxial opening to receive the advancing tubing, and arranging the complementary forming wheel on an inclined fixed axis which intersects the axis of the hollow shaft so that the periphery of the wheel is directly opposed to the periphery of the nose, a tin of extremely small radial extent may be formed.

From the foregoing it is believed that the invention may be readily understood by those skilled in the art, without further description, it being borne in mind that numerous changes may be made in the details of structure without departing from the spirit of the invention as set forth in the following claims.

What we claim:

1. In apparatus for forming spirally wound finned tubing, including a hollow guide shaft, means for rotating said shaft, and means for continuously rotating and advancing longitudinally through said shaft, a length of tubing; a strip feeding and fin forming assembly comprising a forming roll fixed coaxially on the exit end of said hollow shaft and rotatable therewith, said roll having protruding therefrom, a substantially frusto-conical smooth forming nose with a coaxial opening to receive said advancing tubing, said nose being rotatable in the same direction and at the same rate of speed as said advancing tubing, a complementary forming wheel freely mounted for independent rotation, on an inclined fixed axis which intersects the axis of said hollow shaft, the periphery of said wheel having a smooth forming surface concentric with the axis of the wheel and arranged in opposed relation to the periphery of said nose, a strip feeding device for delivering a continuous strip of metal between the opposed peripheries of said wheel and nose, and means for adjusting the angle of the axis of said wheel to regulate the plane of presentation of the periphery of said wheelto the periphery of said nose.

2. In apparatus for forming spirally wound finned tubing, including a hollow guide shaft, means for rotating said shaft, and means for continuously rotating and advancing longitudinally through said shaft, a length of tubing; a strip feeding and fin forming assembly comprising a forming roll fixed coaxially on the exit end of said hollow shaft and rotatable therewith, said roll hav- However, with the present invention, by v ing protruding therefrom, asubstantially frusto-conical smooth forming nose with a coaxial opening to receive said advancingtubing, said nose being rotatable in the same direction and at thesame rate of speed as said advancingtubing, a complementary forming wheel freely mounted for independent rotation, on an inclined fixed axis which intersects the axis ofsaid hollow shaft, the periphery of said wheel having asmooth forming surface concentric with the axis of the wheel and arranged in opposed relation to the periphery of said nose, at strip feeding device for delivering. a continuous strip of metal between the opposed peripheries of said-wheel and nose, means for adjusting the angle of the axis of said wheel to regulate theplane for presentation of the periphery of'said wheel to the periphery of said nose, and means for positioning the strip feeding device to present said strip edgewise to said tubing, in a non-radial planewhich intersects theper-ipheryof'said tubing.

3. Apparatus as claimed in claim 2, including means located anterior to said feeding device, for forming an angular-flange along one longitudinal edge of said strip, saidfeeding device presenting said strip to the periphery of said tubing with the preformed flange in contact with the'latter.

4. Apparatus asclaimed in claim 3, including a swedging roll: arranged for engagement with said preformed flange, after the coiled fin and'tube leave the forming mechanism.

5. Apparatus as claimed in claim 3, including a swedging roll arranged for engagement with said preformed flange, after the coiled fin and tube leave the forming mechanism, spring means normally urging said swedging roll into contact with said flange, and means for retracting said swedging roll from said tubing.

6. In apparatus forforming spirally wound finned tubing, including a frame, a hollow guide shaft supported by said frame, meansfor rotating said shaft, and means for continuously rotating and advancing longitudinally through said shaft, a length of tubing; a strip feeding and fin'forming assembly comprising aforming roll fixed coaxially on the exit end of said hollow shaft and rotatable therewith, said roll having protruding therefrom, a substantially frusto-conical smooth forming nose with a coaxial opening to receive said advancing tubing, said nose being rotatable in the same direction and at the same rate of speed as said advancing tubing, a complementary forming wheel freely mounted on said frame for independent rotation, on an inclined axis which intersects the axis of said hollow shaft, the periphery of said wheel having a smooth forming surface concentric with the axis of the wheel and arranged in opposed relation to the periphery of said nose, a strip feeding device for delivering a continuous strip of metal between the pposed peripheries of said wheel and nose, a mounting p 8 respect: to said tubing, and means for adjusting thetangle. of the axis; of said wheel to regulate the *planeof presentation=of the periphery of said'wheel, to theperiphery of said-nose.

7. Apparatus as claimed in claim 6, including a main mounting plate on said frame, supporting said forming wheel and-mounting rod andmeanshingedly supporting one edge ofsaid'mounting plate, whereby said plate and the elements supported thereby may be retracted from said tubing.

8. Apparatus as claimed inclaim 7, including a lock bolt" extending between said hinged plate and a fixed lug on said frame, for locking said plate and the-elements supported" thereby, in operative position;

9. In apparatus for forming spirally wound finned tubing, including a hollow guide shaft, means for-rotating saidshaft, and means for continuously rotating'and ad'- vancinglongitudinallythrough said shaft, alength of tubing; a strip feeding and fin forming assembly-comprisinga forming roll'fixed coaxially on the exit end of saidhollow shaft and rotatable therewith, said roll having protruding therefrom, a substantially frusto-conical smooth form-ing'nose witha coaxial opening to receive said advancing tubing, a complementary forming wheel freely mounted for independent rotation on an inclined axis which intersects theaxis of said hollow shaft, the periphery of said wheel having a smooth forming surface concentric with the axis of the wheel and arranged in opposed relation to the periphery of said nose, the bottom of said' wheel being dished to provide a concentric recess, a strip feeding devicefordelivering a continuous strip of metal between the opposed peripheries of said wheel and nose, means for adjusting the angle of the axis of said wheel to regulate the plane of presentation of the periphery of said wheel, to the periphery of said nose, and a swedging roll rotatably mounted on an axis parallel with that of said hollow shaft, for swedging a tube contacting flange portion on said strip material against that portion of-the tube on the side opposite the forming wheel;

10. Apparatus as claimed in claim 7, including means associated with said mounting plate for regulating the pressure of the periphery of said forming wheel on said forming nose.

References Cited in the file of'this patent UNITED STATES PATENTS.

1,472,719 Horvath Oct. 30, 1923 1,623,766 Way Apr. 5, 1927 1,840,317 Horvath Jan. 12, 1932 1,850,936 Lane Mar. 22, 1932 1,863,552 Berg June 14, 1932 1,981,566 Nigro Nov. 20, 1934 1,997,197 Nigro Apr. 9, 1935 2,145,244 Berg et a1. Jan. 31, 1939 2,151,685 Berg Mar. 28, 1939 2,262,227 Fulson Nov. 111, 1941 2,437,500 Bruegger Mar. 9, 1948 2,532,239 Newlin Nov. 28, 1950 2,613,066 Newlin Oct. 7, 1952 2,635,571 Edwards Apr. 21, 1953 2,667,337 Chapman Jan. 16, 1954 2,812,794 Chapman Nov. 12, 1957

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