US2570470A - Bladed roll for working hides - Google Patents

Description

Oct 9 1951 v. H. MEYER ETAL BLADEO ROLL FOR WORKING HIOEs Filed may 1e, 195o In vento/S Vernon H Meyer Donald M Ferguson Aim ' Tr ,n 1

| 'Il 'I l1 n Patented Oct. 9, 1951 STATES PAT-ENT OFFICE y l 25mm y BLADED ROLL Fon WORKING HIDEs Vernon H. Meyer,- Beverly, andDonald M. Ferguson, Marblehead, Mass., assignors. to United.

Shoe Machinery Corporation, Flemington, N. J a corporation fof New Jersey Application Maly'l, 1950, Serial N0. 162,253

"7 Claims. (Cl. 69--37) :i I v Thisv invention relates to rolls provided with vblades for usefin tanning machinery', and is,.- hereirr illustrated as embodied in a roll vhaving helicalblades for performing a eshing, shaving or an analogous operation upon hides, skins or leather. Itf is to be understood, however, that the invention is not limited in use to blades or rolls of theillustrated. type.

' The vpsent vapplication is av continuation-inpart of applicationserial No.46,658, led August 33,51948,.now abandoned.

lllfhileflhelically` bladed rolls are commonly used in tanningfmachinery they are difficult to manuffac-ture, at least as heretofore constructed, and frequently-they have been found to be or have become defective during use. The blades. themsclvesmust be accurately formed and the roll for supperting them preferably should present "an/integrated structure lcarefully balanced dynamicallyfif the Work on the hides or skins is to be smoothly performed and the.. blades properly supported vso a'sto withstand the, severe strains and stresses imposed upon them during use. Heretofore, steel rolls have been used having carefully and accurately machined helical grooves in which the helical blades are secured and held on therolls by wedgng .them in position in the helical grooves. The wedging is customarily done .by hammering strips of ysoft brass or like metal into the grooves on at least one side of each blade. The methods of mounting the blades upon .the rolls, the `distortion of the blades because of heatv treatment to gain hardness' variationsin the blade metal composition, and the necessity for frequent regrinding all con- `tribute to unevenness in the work produced and -toloss in production time.

Special alloys which are resistant tov abrasion have been available for some time but they have not heretofore been yadopted in making tanning machinery blades.

Probably the reason for this is that such Ialloys alrein general very brittle, are known to be. difficult to manufacture accurately into comp-lex for-m, and have met. with many complica-tions V.'fpiral blades integral-therewith.- "An advanta- 2 geous featureof the invention is the interlocking of the parts, including the-shaft, to give a rigid, strong and reliable unit. Another feature of the invention is the substantially non-ferrous cobalt base abrasion-resistant alloy as preferably utilized f-or the Iblade Iand cylinder material.

These and other important features of the invention and novel combinations of parts will now be described in detail in the lspecification andk then pointed out more particularly in the appended claims.

In the drawing,

VFig. l is a view of the bladed rollof thepresent invention; and

Fig. 2 is a sectional View along the lineII-II of Fig. l. y

As seen in Fig. 1, the bladed roll comprises shaft I il which ismachined at each end forjournaling in the frame of a tanning machine. The central portion or longitudinal section I2 of the shaft I0 is fluted and inthe particular design disclosed, eight longitudinal grooves I4 are shown. Mounted concentrically upon and closely fitting the shaft I0 are two bladed cylindrical Sections 5 I6 and I8 and these two sections are retained inv position on the shaft by collars 2U and 22 fixed to the section I2 by means of set screws `3Il. Both sections I6 and I8 have longitudinal internal ridges 24 for a purpose to ybe described. Cast in.- tegral with 4the cylindrical section IIS are blades 32, each ofv which ascribes a right-handhelical path and the other cylindrical section I8 is provided with similar blades 34 but which are -to the opposite hand. The two sections I6 and. la are interlocked and in abutting relation and the interlocking or 'abutting surfaces are in the nature of an annular sawtooth or Zig-zag arrangement as can 'be understood by reference to Fig.. l. The arrangement of the helicalA :blades is such that Vthe inner end of each blade intersects the side of a blade of the other section and also conforms with one of the surfaces inthe saw-tooth arrangement referred to-i. e.-the blades as well as the -cylinders are in interlocking relation. The outer ends 40 of the blades are rounded'to guard against any possible scratching of the surfaces to be worked upon and the outer circumferential edge orV cutting side of each blade 32 or 34 is ground to present an outer surface or edge which is exactly concentric with the center of the shaft I0.

In the assembly of the complete roll, the cylindrical bladed sections I6 and I8 are assembled upon the shaft I0 in the positions shown and metal such as molten Woods alloy is poured into the grooves I4. When the molten Vmetalhas hardened, the ridges 24 of the cylindrical sections I 6 and I8 are rigidly locked within the Woods alloy and the sections are tightly joined to the steel shaft IU and this construction, together with the sawtooth abutting surfaces and the collars 20, serves to hold the parts in rigid assembly. Static and dynamic balance may easily be imparted to the assembly by drilling away material or otherwise treating section I2 of the shaft l0. As stated previously, abrasion-resistant alloys have been known heretofore but their vuse as tanning machinery blades has not been adopted. Such alloys are generally very hard at least at room temperatures and likewise very brittle. The difficulties to be encountered in incorporating such materials for blades is obvious. and it appears to be quite an obvious one, harder alloys will wear much less rapidly than softer ones. However, attention should be given to the operating conditions which are to be encountered during use and in this connection any measurement of the hardness of the alloy or its Wear resistance is meaningless unless taken at the operative temperature. In other words, the operative hardness and not the room temperature hardness is the true criterion of wear resistance. It is believed, and there is evidence to show, that shaving blades develop a very high temperatur-e at extremely localized working areas such as the cutting edges. The high temperature undoubtedly minimizes the lubrication which may be derived from the fluid which may be in the hide or skin and it also gives rise to corrosion of the cutting edge metal. Abrasion occurs as a natural sequence'of the corrosion.

Applicants have found that a cobalt base'allcy may be used in making a bladed roll and that it retains its hardness at the operative temperatures encountered in the use of helical blades for tanning machinery. Cobalt base alloys are harder as cast and without further heat treatment than any other known alloy except those of the tungsten carbide class. They have a low coelcient of friction, take on-a high polish, are highly resistant to chemical corrosion, the coefficient of expansion is the same as that of steel, and heat treatment is'not necessary in order to gain the hardness. A group of alloys known as Stellite is made by the Haynes StelliteCompany of Kokomo, Indiana. The Stellite alloys comprise a group of hard, abrasionand corrosion-resistant, substantially non-ferrous alloys containing by weight 40 to 80 per cent cobalt, 20 to 40 per cent chromium and to V25 per cent tungsten. Applicants have preferred an alloy'called Stellite No. 12. This particular alloy by weight comprises 47 per cent cobalt, 34 per cent chromium and 10 per cent tungsten, the balance of 9 per cent being impurities. It will be appreciated that the cornposition of the cobalt base alloy may be varied somewhat but it must be substantially nonferrous and in addition to the cobalt base the balance of the composition of the alloy should be selected from the chromium group of metals. By the chromium group` applicants refer to chromium, tungsten, molybdenum, and uranium.

vApplicants have found that the cylindrical sections IB and i8, together with their blades and internalI ridges 24, may bercast as units by means of the lost wax process otherwise known as the precision investment castings method. This method is widely used at the present time for the formation of both simple and intricate castings. The method is well described in the June 5, 1948 issue of Business Week, pages 48 to 56.* It is As a rule,

4 also described in the book entitled, Precision Investment Castings written by Cady and published in January, 1948 by the Reinhold Publishing Corporation, New York. For the instant purpose, the method may be described by stating that precision casting begins with a master pattern of the partto be produced. The master pattern is machined of brass or bronze and is used to form or cast the mold into which the melted wax is later injected. This wax is introduced under controlled pressure and temperature and hardens to form a wax replica of the desired part or element of the desired part. Several elements may be waxed together to form the nal waxed replica. In making each of the bladed sections I6 and i8, applicants found it advantageous to make eight helical segments in wax with each segment including a blade and a helical strip of the cylinder. Eight of these strips are then joined by means of wax to form a wax bladed replica of a cylindrical section. This wax replica is then given a primary investment coat which may be a mixture of ne silica and sodium silicate that will form the smooth inner surface of the nal mold after the wax is melted out. A

E it is hardened the flask is heated to melt out the wax. The flask is then heated to metal pouring temperature and the proper metal alloy is'poured into the cavity left by removal of the wax'.l In order to avoid imperfections,v the molten. alloy is poured into the flask cavity under pressure in-' duced by rotating the flask or by theus'e of-'a static head of alloy or air pressure. Ani example of an apparatus for driving the molten metal in'to the mold is disclosed in United States Letters Patent No. 2,125,080, granted on July 26,- 1938 in the name of Albert W. Merrick. The investment is then removed from the castingwhich is gen'- erally ready for use vexcept that-possible roughV spots may require slight grinding;

It will be understood that the substantially non-ferrous cobalt base type of alloy is preferred for the blade compositionbut the invention is? not limited in its? application to the use of such`- a composition. Someaspects of the invention may be practised using case-hardened steel 'or other suitable wear-resisting metals for the mak ing of the blades and/or the cylinders.

Having lthus described our invention, what we claim as new and desire to secure by Lettersv Patent of the United States is: 1. As an article of manufacture, a tanning machine roll comprising a shaft, multiple cylin-v ders arranged in end-to-,end and interlocking relation on said shaft, each of said cylindershavi` ing spiral blades formed integral therewith. 2. As an article of manufacture, a tanning machine roll comprising a shaft, a cylinder concentric with said shaft and having helical blades formed integral with the cylinder, and the cylin-l der being locked in place on the shaft by lmetal cast between them. 5

3. As an. article of manufacture, -'atanning` machine rollcomprisinga shaft with longitudinall grooves, a cylinder concentric withV said shaft and having helical blades on its exterior. and ridges on its interior, the said ridges being vlocked in said grooves by-metal cast in place, andthev cylinder, blades and ridges being integral/tp forma one-piece construction;

l4. Aswan article of manufacturaa machine roll comprising a shaft with grooves, a cylinder concentric with said shaft and having helical blades on its exterior and projections on its interior, and the said projections being locked in said grooves by metal cast in place.

5. As an article of manufacture, a tanning machine roll comprising a shaft with longitudinal grooves, multiple cylinders concentric with said shaft and arranged in end-to-end and interlocking relation on said shaft, each of said cylinders being of cast metal with spiral blades on its eX- teror and projections on its interior, the said projections being locked in said grooves, and the said cylinders, blades and ridges being composed of a substantially non-ferrous, abrasion-resistant cobalt base alloy containing at least one of the metals from the chromium group.

6. As an article of manufacture, a tanning machine roll comprising a shaft with longitudinal grooves, a cylinder concentric with said shaft, said cylinder being of cast metal with helical blades on its exterior and ridges on its interior, the said ridges being locked in said grooves by metal cast in place, and the said cylinder, blades and ridges forming an integral structure of the following composition by weight:

40 to 80 parts cobalt 20 t0 40 parts chromium 0 to 25 parts tungsten 7. As an article of manufacture, a tanning machine roll comprising a shaft provided with grooves, a cylinder concentric with said shaft and having formed integral therewith outwardly extending helical blades and inwardly extending ridges opposite to the grooves in said shaft, each of the grooves being substantially wider than each of said ridges, and the cylinder and shaft being secured together by metal cast in said grooves.

VERNON H. MEYER. DONALD M. FERGUSON.

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

UNITED STATES PATENTS

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