US1179788A - Rim for pressed-steel split pulleys. - Google Patents

Description

R. J. WALTHER.

RIM FOR PRESSED STEEL SPLIT PULLEYS.

APPLICATION FILED MAR. 13. 1913.

Patented Apr. 18, 1916.

FIC% I Iowa/Mm Rummz J maxim;

7 structure.

"UNXELU hTAhld PATENT @Flitll RICHARD J.,'W'ALTHEB, 0F: PHILADELPHIA, PENNSYLVANIA, ASSIGNOB TO THE AMERICAN PULLEY COMPANY, OF PHILADEL?HIA, PENNSYLVANIA, A CORPO- RATION OF PENNSYLVANIA.

RIM FOR PRESSED-SIEEL SPLIT PULLEYS.

Application filed March 13, 1913.

To all whom it may concern Be it known that I, RICHARD J. lVAL'rnnn, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Rims for Pressed-Steel Split Pulleys, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to a particular type of the so-called splitpulleys comprising two semi-circular thalfspulleys, adapted to be secured to one another and to a central shaft, the particular type thereof being that in which the rim of each half pulley is itself built up from two similar members of pressed sheet steel, which meet, and are secured together, on a plane at right angles to the central axis of the pulley, and which may be termed the median plane of the As each half-pulley comprises two such members, each of the latter can stitutes one-quarter of the rim of the entire pulley, and for purposes of convenience of description, each will be hereinafter termed a quarter-rim.

In the accompanying drawings, Figure 1, represents, in side elevation, a complete split-pulley whose rim embodies a preferred form of my improvements, a portion of the rim adjacent to the abutting ends of the half-pulleys, at the bottom, being represented as broken away, and shown in vertical section, in order to illustrate the position of certain parts. Fig. H, is a view, in elevation, of the uppei; abutting end of the rim of that half-pulley which is at the left hand side in Fig.1," said Fig. 11, showing, in one quarter riin, the position of certain parts in the process of building up the structure, and, inthe other quarter-rim, the said parts in t lieir final embodiment. Figs. HI, and lv are views, in elevation, of a portion of the/abutting end of a quarter-rim, indiou ing, in each instance an embodiment of lily/invention with certain differences of detail,

,lvly improvements are addressed to remeying certain peculiar defects or objectionable tendencies frequently found in the rim of half-pulleys of the type abdve described.

As heretofore ordinarily made the quarterrims for such pulleys have been constructed by cold-pressing sheet steel to form an ex- Specification of Letters Patent.

Patented Apr. its, 1916.

Serial in). 753,838.

tended flat semi-annular band such as that indicated at 1, in Figs. I, and H, (whose surface contour is either cylindrical or slightly coned), the outer edge of the band being usually returned upon itself to form a bead 2, while the inner edge is turned abruptly inward to form a deep radial flange 3, substantially at right angles to the outer surface of the rim. The correlative quarter rim is constructed in like manner and the two flanges 3, 3, meeting on the median plane above referred to, constitute the region of attachment of the quarterrims to one another and to. the spokes d, which are secured by rivets 5, or in any other well known manner. The spokes at, are riveted to the hub-shells 6, and the latter are adjustably secured to one another and to the shaft by clamping bolts 7, as is well understood. In this class of pulleys, when so constructed from cold-pressed metal, it is found that there is a peculiar tendency to crack at the end region immediately adjacent to thefcorner formed by the annular rim and inwardly turned flange. This tendency may possibly be due to enhanced crystallization or modification of the molecular structure of the metal as a consequence of the strains produced by abruptly bending the flange inward, but whatever may be the cause, the tendency to crack manifests itself at, and may be said almost to be restricted to, the particular region referred to, viz: that immediately adjacent to the abutting ends of the quarter-rims, where there is no direct support by the spokes and where the metal is subjected to torsional strains, often irregular and unequally distributed. Experience has shown that this diliiculty cannot be satisfactorily remedied by mechanically securing separate reinforcing-pieces at this region. The means about to be described for obviating the tendency have been developed as the result of various experiments, and it is found that by employing them the tendency to crack at the region referred to can practically be obviated.

I will now proceed to describe my invention in the light of the foregoing explanation of its purpose.

Adjacent to each abutting extremity of the quarter rim, I apply within the angle formed by the abruptly bent flange 3, and

annular band 1, a short piece, preferably of soft steel heavy wire, 8, as indicated in the left hand quarter-rim shown in Fig. II. This piece which I term the terminal corner piece is then welded into the angle between the band 1, and flange 3, either by'electric welding or any other convenient process, pressure being applied to a degree suflicient to unite the metal of the piece with the metal of the adjacent parts lying immediately within the angle and at the immediate extremity of the quarter-rim, the initial cross section of the terminal corner piece being so modified as to assume as its final form the cross section indicated at 9, in Fig. II. The slight deformation of the terminal corner piece, which attends the act of welding, does not injuriously affect the internal structure of the member itself. and I believe it to be the fact that the heating incidental to the welding, and the subsequent normal or slow. cooling of the parts, produces a desirable annealing effect upon the immediately adjacent metal of the rim, which alleviates the tendency to crack above referred to. In the completed structure each quarter-rim comprises two such Welded terminal corner pieces, located as above stated, so that the entire pulley (made up of the two composite half-pulleys) will embody eight such terminal corner pieces. It is found, under these circumstances, that the life of the metal at the region of the abutting ends of the half-pulley portions, is greatly prolonged, and the tendency to crack practically eliminated.

In Figs. III, and iv, I have shoa at.

1.0 and 11, respectively, modifications of the ultimate form of the terminal corner piece, merely to indicate that my invention is not restricted to any particular forms of cross section of the metal which constitutes such member. It will be noted, 11owever,that the cross sectional area of the terminal corner piece, as well as its peri heral extent, is relatively small, so that it is wholly comprised within the region immediately adjacent to the angle of the flange and band at the extremity of the rim, the region of welding contact being correspondingly limited. Hence the physical or structural consequences of the welding do not extend beyond the Very limited region in which the defects soughtto be cured exist, as there is no substantial addition to the weight of the structure, or mechanical complication such as would be due to the presence of additional separable members.

I am of course aware that broadly speaking, the use of a reinforcing piece at a region of weakness in pulleys, is not a patentable expedient, and I do not broadly claim such a device. Nor do I claim broadly the employment of an increase of cross section in an integral piece of metal as a reinforcing element, nor the use of such an adjunctive member as a dowel pin intended to be separably inserted to connect the adjacent meeting ends of rim portions.

My invention is restricted to a peculiar type of pulley which, as a consequence of its manufacture, has certain inherent structural defects; it is addressed to meeting these undesirable conditions peculiar to that type; and its action toward obviating such conditions is not that of mere duplicative strengthening or support, in a mechanical sense, but is due to qualities-developed in a unitary structure, when the terminal corner piece has been merged into integrity therewith, under the peculiar conditions which attend its application.

Having thus described my invention, I claim:

In a pressed steel pulley, the combination of four separate quarter-rims, each quarter rim comprising a flat semi-annular band having an integral radial flange extending inward substantially at right angles to the peripheral surface of the band, and adjacent to themedian plane of the pulley, and terminal corner-pieces of relatively small cross sectional area and relatively short peripheral extent, integrally welded to the internal surfaces of the band and flange, directlyfivithin the angle formed by them, immediately adjacent to the respective ends of the quarter-Trim, substantially as set forth.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this eleventh day of ltilarch, 1918.

RICHARD J. WALTHER.

Witnesses JAMES H. BELL, E. L. FULLERTON.

Copies o1. this patent may be obtained for 'five cents each, by addressing the Commissioner or Patents Washington, D. G.

Images