US3913863A

US3913863A - Cast aluminum textile beam

Info

Publication number: US3913863A
Application number: US397085A
Authority: US
Inventors: Arthur S O'malley
Original assignee: Hayes-Albion Corp
Current assignee: Hayes-Albion Corp
Priority date: 1973-09-13
Filing date: 1973-09-13
Publication date: 1975-10-21
Anticipated expiration: 1992-10-21
Also published as: DE2443159A1; GB1459114A; DE2443159C3; DE2443159B2; CH580026A5; FR2244030A1; FR2244030B1

Abstract

A textile beam construction consisting of a barrel and a cast aluminum head secured to each end thereof. Each head has a hub portion with a cylindrical surface extending axially of the beam and has a retaining surface extending outwardly in radial relation to the cylindrical surface. An annular concave surface or fillet is formed on each head at the junction between the cylindrical and retaining surfaces, and the ultimate strength of each head is materially increased by providing residual compressive stress in the material forming the annular fillet. This fillet is initially formed on a radius greater than the desired finished radius, and a rolling operation is carried out on the fillet surface to apply a compressive force which reduces the radius to finished dimension and creates the residual compressive stress in the cast material of the head forming the fillet surface.

Description

United States Patent [1 1 OMalley Oct. 21, 1975 CAST ALUMINUM TEXTILE BEAM Arthur S. OMalley, Charlotte, NC.

[73] Assignee: Hayes Albion Corporation,

Charlotte, NC.

22 Filed: Sept. 13, 1973 21 Appl. No.: 397,085

[75] Inventor:

Primary Examiner-George F. Mautz Attorney, Agent, or FirmFarley, Forster and Farley [57] ABSTRACT A textile beam construction consisting of a barrel and a cast aluminum head secured to each end thereof. Each head has a hub portion with a cylindrical surface extending axially of the beam and has a retaining surface extending outwardly in radial relation to the cylindrical surface. An annular concave surface or fillet is formed on each head at the junction between the cylindrical and retaining surfaces, and the ultimate strength of each head is materially increased by providing residual compressive stress in the material forming the annular fillet. This fillet is initially formed on a radius greater than the desired finished radius, and a rolling operation is carried out on the fillet surface to apply a compressive force which reduces the radius to finished dimension and creates the residual compressive stress in the cast material of the head forming the fillet surface.

4 Claims, 3 Drawing Figures CAST ALUMINUM TEXTILE BEAM SUMMARY OF THE INVENTION This invention relates to an improved construction for a textile beam or spool having a cast aluminum head secured to each end of a central portion or barrel, and to an improved method for manufacturing such a head of cast aluminum to provide the desired amount of ultimate strength.

Conventionally, a textile beam or relatively large spool consists of a cylindrical barrel to which a pair of heads are secured, each head having a hub with a cylindrical surface portion at one end of the barrel and extending axially thereof, and having a retaining surface portion extending radially outward of the hub. For the larger sizes of beams or spools used in the textile industry, such as the so-called tricot beams employed for fine denier nylon yarn, the heads of the beam have been made as aluminum forgings, and while this adds considerable expense to the article, no other type of construction has been known which satisfies the requirements for minimum weight and for sufficient strength to withstand the high loads imposed when the beam is wound with yarn. Beams or spools have been manufactured with heads made of cast aluminum, but only in smaller sizes and for light duty service because of the relatively low ultimate strength of this type of construction.

Recently it was thought possible, in view of improved techniques and quality controls available in the aluminum founding art, to manufacture a tricot beam with cast aluminum heads at a cost considerably below that required for the same beam with forged aluminum heads. Attempts to do this did not prove successful. Repeated test failures were encountered with cast aluminum heads at loads well below the ultimate strength required for safe and satisfactory service. For a nylon tricot beam, having heads 30 inches in diameter, a minimum breaking strength of 275,000 lbs. is desired, which is an easily attainable figure with the forged construction and which seemed to be attainable in a cast construction. With cast heads however, it was found by test that failures could occur at loads less than half the desired breaking strength, and even though an average figure for the ultimate strength of the cast head beam was higher, it was still well below that necessary for safe operation in service, where the failure of the head of a beam can be a very dangerous and costly accident due to the magnitude of the forces involved.

The present invention provides a beam construction in which the forged aluminum heads can be replaced at an appreciable saving in cost with heads made of aluminum castings and having an ultimate breaking strength suitable for tricot and other relatively high loading applications. The invention also provides a method for commercially manufacturing a cast aluminum head for a beam or spool having a marked increase in ultimate breaking strength in comparison with such a cast aluminum head produced without the use of this method.

In the textile beam construction of the invention, which includes a cylindrical barrel and a head secured to each end of the barrel, each head has a hub with a cylindrical surface forming a continuation of the barrel and has a retaining surface extending radially outward from the cylindrical surface. Each head consists of an aluminum casting provided with an annular concave surface forming a fillet at the junction between the cylindrical and retaining surfaces thereof, and the cast aluminum material forming the annular fillet has a residual compressive stress provided therein when the beam is in an unloaded condition. Preferably, this residual compressive stress is on the order of 25,000 lbs. per square inch.

The invention provides a method for making a cast aluminum head for a textile beam or spool in which the concave fillet formed at the junction between the cylindrical and retaining surfaces of the head is initially formed with a radius having a dimension in excess of that desired for the finished dimension of the radius of this fillet, and a compressive force is applied to the annular fillet surface to reduce the dimension of the radius thereof to the desired finished dimension and to thereby create the residual compressive stress in the material of the head forming the annular fillet surface.

Preferably the method is carried out by employing a roller provided with a convex peripheral profile formed on a radius having the dimension of the finished radius of the fillet; and, this roller is additionally provided with marginal portions bordering the convex peripheral profile, which marginal portions are at right angles to each other and engage the cylindrical and retaining surfaces of the head during the rolling operation to limit the action of the compressive force applied to the fillet surface.

Other features and advantages of the invention will appear from the description to follow of the representative embodiment thereof disclosed in the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation showing the principal components of a textile beam or spool and illustrating the forces to which these components are subjected when a material is wound thereon;

FIG. 2 is an enlarged sectional detail taken through a head of a beam constructed in accordance with the invention and showing the junction between the hub and yarn retaining surface portions thereof; and,

FIG. 3 is a sectional detail similar to FIG. 2 illustrating a method for the manufacture of a cast aluminum beam head according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment to be described herein illustrates an application of the invention to the construction of a textile beam, but it will be appreciated that the principles involved can be applied to the construction of other types of large spools.

A conventional textile beam 10, schematically illustrated in FIG. 1, consists of a cylindrical barrel 12 whose axis defines the axis of the beam, and a head 14 suitably connected to the barrel at each end 15 thereof. Each head 14 has a hub 16 with a cylindrical surface 17 extending axially of the beam to form a continuation of the cylindrical barrel 12, and has a retaining surface 18 extending radially outward of the cylindrical surface 17.

When the beam 10 is wound with yam 19, compressive forces are imposed upon the barrel 12 as indicated by the arrows 20, and spreading forces are imposed upon the retaining surfaces 18 of the heads as indicated by the arrows 22. As a result of these forces, high tensile stresses are created at the junction between the cylindrical surface 17 and the retaining surface 18 ofeach of the heads 14, at which junction an annular concave surface of fillet 24 is conventionally provided. Most beam failures under yarn loading occur at this junction.

FIG. 2 gives an enlarged sectional view of the junction between the cylindrical surface 17 and retaining surface 18 of the head of a beam constructed in accor dance with the invention. In this view, a portion of the barrel 12 is indicated in broken line together with a connection between the hub 16 and the barrel 12 such as disclosed in U.S. Pat. No. 3,317,160.

The head 14 shown in FIG. 2 comprises an aluminum casting provided with the annular concave surface or fillet 24 at the junction between the cylindrical surface 17 and the yarn returning surface 18 of the head. The cast aluminum material which forms the annular fillet 24 has a residual compressive stress provided therein, as indicated by the shaded area 26, when the beam is in an unloaded condition.

FIG. 3 illustrates a preferred method for making the cast aluminum head 14 of FIG. 2. A concave annular fillet 24a is formed at the junction between the cylindri cal surface 17 and the retaining surface 18 of the head on a radius having a dimension in excess of that desired for the finished dimension of the radius of the fillet 24 of FIG. 2. Then, a compressive force is applied to the annular fillet surface 24a to reduce the dimension of the radius thereof to the desired finished radius of the fillet 24 and to thereby create the residual compressive stress in the area 26. In FIG. 3, the application of compressive force to the fillet surface 24a is performed by employing a roller 28 having a convex peripheral profile 30 formed on a radius having a dimension conforming to the desired finished radius of the fillet 24. The roller 28 is also provided with

marginal portions

32 and 34 bordering the convex peripheral profile 30 thereof, which marginal portions are at right angles to each other. When the rolling operation is carried out under a compressive force indicated by the arrow 36, the

marginal portions

32 and 34 on the periphery of the roller 28 eventually engage the retaining surface 18 and the cylindrical surface 17 of the head, respectively, thus limiting the action of the compressive force applied to the arcuate fillet 24a and insuring that the fillet is rolled to the desired finished radius.

The invention will be further described with reference to tests performed on beams for nylon tricot applications with cast aluminum heads 30 inches in diameter. In one test, some of these heads were provided with a fillet 24 machined or cut to a standard radius of 0.093 inch. Other samples were made with a fillet 24a cut to a radius of 0.125 inch and then rolled to the radius of 0.093 inch by the method shown in FIG. 3, applying a compressive force on the order of 2,500 lbs. Test beam specimens were made, some of these specimens being provided with the heads having the cut fillets and other specimens being provided with heads having the rolled fillets.

Static load tests showed that the beams with cut fillet heads failed between 160,000 and 304,000 pounds with an average failure load of 243,000 pounds. Beams with rolled fillet heads failed between 255,000 and 349,000 pounds with an average failure load of 321,000 pounds. On the average, the beams with rolled fillets had an ultimate strength approximately one-third greater than the beams with cut fillets; also, all beams with rolled fillets failed above a load of 225,000 pounds with figure was established as a minimum test value for satisfactory commercial production. In contrast, failures of beams with cut fillets occurred below this minimum test value in sufficient number to make the cut fillet construction not feasible for commercial production because of the high scrap losses that could be expected. In another test conducted, two 30 inch nylon tricot cast aluminum heads, one with a 0.093 inch radius cut fillet and the other with the fillet cut to a 0.125 inch radius and then rolled to a 0.093 inch radius, were each instrumented at the fillet with 8 foil type resistance strain gages. The two test heads were loaded, against an 18.5 inch diameter load ring, using a 1.2 million pound capacity Baldwin load test machine to determine the comparative effect of fillet rolling on fillet strain under load, at rest after load and at failure. Static strain readings were taken under load at 25,000 pound intervals from 0 to 150,000 pounds, and at rest after this load cycle. Dynamic strain was then recorded continuously from zero load to failure. At 150,000 pounds load, the cut fillet showed plus 6170 micro-strain, the rolled fillet plus 5650 micro-strain, or 520 micro-strain less. The peak fillet strain at rest after 150,000 pounds load, or the zero shift, showed the cut fillet with plus 1303 micro-strain, the rolled fillet plus 149 micro-strain, or an 88.6 percent reduction in the zero shift. The failure load for the cut fillet was 284,000 pounds, for the rolled fillet 370,000 pounds or a 30 percent increase in strength. Peak fillet strain at failure for the cut fillet was 18,750 micro-strain, for the rolled fillet 24,000 microstrain or an increase of 5250 micro-strain. The large differential in peak fillet strain at rest after load, or zero shift, gives a very definite indication that fillet rolling has altered the fillet stress level prior to loading. The higher strain at failure in the rolled fillet leads to the conclusion that the fillet rolling operation does create residual compressive stress, and that it is of the order of magnitude of 5,000 micro-strain.

Further investigation of the residual compressive stress was made by x-ray stress analysis, and indicated a residual compressive stress of approximately 29,000 p.s.i. in the area of the fillet formed with the rolled radius of 0.093 inch as described herein. A fillet formed with the cut radius of the same dimension was found to contain no detectable residual compressive stress.

The foregoing tests demonstrate the significant increase in ultimate strength obtained in a cast aluminum beam head made with the rolled fillet by the method illustrated in FIG. 3 and described herein. These tests also prove that the rolling operation creates a residual compressive stress in the cast aluminum material of the head forming the rolled fillet 24.

While other techniques, such as shot peening could be employed to apply the compressive force to the fillet surface 24a necessary to reduce the radius thereof to the final dimension of the fillet 24, the rolling operation disclosed is presently preferred because of the ease with which it can be controlled. This method makes the production of textile beams with cast aluminum heads commercially practical, and with a considerable reduction in cost as compared with the conventional construction using forged heads.

I claim:

1. A textile beam or spool comprising a cylindrical barrel whose axis defines the beam axis, and a head secured to each end ofthe barrel, each head having a hub with a cylindrical surface extending axially of the beam is in an unloaded condition, said residual compres-.

sive stress being localized in that portion of the cast aluminum material which forms said annular concave surface.

2. A textile beam or spool according to claim 1 wherein said residual compressive stress is on the order of 25,000 pounds per square inch.

3. A head for a textile beam or spool, said head having a hub with a cylindrical surface, a retaining surface extending radially outward from said cylindrical surface, and a concave annular fillet at the junction between said cylindrical and retaining surfaces; wherein the material of said head is provided with a residual compressive stress which is localized at said concave annular fillet.

4. A head according to claim 3 wherein said residual compressive stress is on the order of 25,000 pounds per UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,913,863

DATED 3 October 21, 1975 INVENTOR(S) Arthurv s, O'Malley It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 1, "with" changed to read -which- Signed and Scaled this tenth Day Of February 1976 [SEAL] A! test:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofPatents and Trademarks

Claims

1. A textile beam or spool comprising a cylindrical barrel whose axis defines the beam axis, and a head secured to each end of the barrel, each head having a hub with a cylindrical surface extending axially of the beam to form a continuation of the cylindrical barrel and having a retaining surface extending radially outward from the cylindrical surface of the hub; wherein: each head comprises an aluminum casting provided with an annular concave surface forming a fillet between said axially and radially extending surfaces; and, the cast aluminum material in each head is provided with a residual compressive stress when the beam is in an unloaded condition, said residual compressive stress being localized in that portion of the cast aluminum material which forms said annular concave surface.

4. A head according to claim 3 wherein said residual compressive stress is on the order of 25,000 pounds per square inch.