US2263780A - Top roll for the drawing mechanisms of spinning, roving, and similar machines - Google Patents

Description

Nov. 25, 1941. R. A. KETTLEY TOP ROLL FOR THE DRAWING MECHANISMS OF SPNNING, ROVING, AND SIMILAR MACHINES Filed July 51, 1940 Patented Nov. 25, 1941 t 2,263,180 Tor Rom'. Foa 'ma DRAWING MEcnANrsMs 0F SPINNING, ROVING, AND

MACHINES SIMILAR Rex ArKettley, Saco, Maine, assignor to Saco- Lowell Shops, Boston, Mass., a corporation of Maine Application July 31, 1940, Serial No. 348,936

3 Claims.

This invention relates to top rolls used in the drawing mechanisms of spinning, roving and similar machines. It has for its general object to produce a superior article of this character.

As is well understood by those skilled in this art, such a drawing mechanism comprises a series of pairs of upper and lower rolls, arranged one in advance of the other, to operate successively on a sliver, roving, or the like, to feed it and to draw it out or attenuate it during said feeding operation. The bottom rolls customarily are long fluted steel rolls and are positively driven by gearing located at one end of the machine. The upper or top rolls, however, are short and customarily are driven only by their contact with the bottom rolls. Partly for the purpose of improving this driving engagement and partly, also, to enable each pair of rolls to exert a better grip on the sliver or roving, the top rolls are pressed rmly against the bottom rolls by means of a weighting mechanism.

A typical top roll comprises a cast iron body provided with two cylindrical roughened bosses connected by a neck of reduced diameter. This body also has short stub shafts or gudgeons projecting from its opposite ends. The bosses are covered with a yielding material, usually comprising a layer of felt or thick cloth, cemented to their roughened circumferential surfaces, this layer, in turnl being covered with a cot made of leather, or some other suitable material, or the entire cover may be made of cork or one of the synthetic rubber compositions. In operation, these cushioned surfaces run in contact with the lower steel roll and the upper roll is held in place by the engagement of its gudgeons with the walls of slots in the cap bars. A saddle bears on the reduced neck and transmits the pressure of the weighting mechanism to the roll.

From time to time the roll covers become worn or damaged and must be replaced. This result is usually accomplished by dumping the rolls in a bath of boiling water and later in one or more other baths containing chemicals adapted to soften the adhesive and thus to loosen the covering materials. Certain of these baths also are designed to remove the adhesive used in securing the covering material to the bosses. In order to facilitate this operation, and sometimes also in connection with drying the rolls, they are Y tumbled with rags or some other suitable material. 'I'his rough treatment frequently damages the rolls by nicking and scoring the journal or friction surfaces of the gudgeons `or necks, or

by abrading the roughened surfaces of the bosses suiliciently to change their shape or diameter and to. make it more difficult to produce a good bond between the metal and the new covering.

The roll above described is that used almost universally, but. in addition to it, there is another type of roll. usually referred to as a shell" roll, which is used to a very limited degree. It consists of a steel shaft or rod on which are mounted two steel sleeves, each covered with leather, cork, orsome of the other appropriate roll covering materials. The rod is supported in the slots of a cap bar, in the same manner as a solid roll, but it remains stationary, the sleeves or shells" revolving around it. The present invention is not concerned with this type of roll, and consequently, the reference to rolls 'or top rolls hereinafter will be understood to designate the solid type of roll unless otherwise expressly stated.

So far asl have been able to learn, the custom universally practiced commerciallyl heretofore has been to make these top rolls from cast iron bars machined to the required shape. Usually the cap bars also are made of cast iron and the two cast iron members running one against the other generally produce glazed surfaces on the bearing and journal parts after they have run for a while which, under proper conditions, are fairly satisfactory. However, due to the differences in hardness and density which always exist in cast iron parts, it is a common experience to find that the rolls wear more rapidly at one of their bearing points than another, or wear down eccentrically. There are also the usual difficulties in connection with the use of cast iron which must naturally be expected, such as its peculiar machining characteristics, its variations in structure, liability to blow holes, and the like.

A further diiliculty experienced in using these cast iron rolls has been that saddles made of cast iron are used almost universally in the textile industry, partly because of their cheapness, and more especially because after they have run for a time on a cast iron roll they gradually, also, take on the glazed surface characteristic of cast iron, and once this surface has been definitely established, they operate quite satisfactorily. However, these saddles are not machined because it is desired to utilize the extremely hard surface scale of the cast iron piece. As a rule, when a new saddle is installed it nearly always, for a time, cuts into the neck of the roll. The

55 fact that the scale on the saddle contains silica seems to be largely responsible for this action, and it is the common experience in using these saddles that they often ruin a cast iron roll in a very few days by the cutting action just mentioned. While this operation .is going on the saddle necessarily exerts arr unusually severe braking effort on the rotation of the roll because the saddle in held against the neck of the roll by a pressure of, say. five to fteen pounds. Consequently, the roll hesitates, its rotative movement is irregular and uneven and, as any spinner knows, such an action of a top roll necessarily results in the production of poor yarn because the drafting operation cannot proceed normally unless the rolls do rotate evenly. If, however, the neck of a roll can stand up under this abrading action until its surface and that of the saddle have become lapped one to the other, then the graphite content of the cast iron begins to exert a mild friction-reducing action which seems to assist in the production of the desirable glaze above referred to.

In this connection it should be pointed out that these rolls necessarily are operated with a very scant supply of oil or other lubricant. In fact, they are usually run in a semi-dry condition because a surplus of lubricant is very likely to get on the yarn or to collect lint and ily which, in turn, finds its way on to theyarn. Either result is highly objectionable. The machine tenders are constantly on the watch for the presence of black oil on the neckslor gudgeons of the roll, and if they find it, they immediately take steps to remove it and to stop its production. The presence of black oil always means that there is an excessive abrasion going on at one or the other of the bearing or friction sur-V faces and that particles removed from said surfaces by such abrasion are being transferred to the lubricating oil.

It will be evident from the foregoing that the breaking in of a new saddle requires a substantial period of time during which the operating conditions are not satisfactory. The same is true of breaking in a new roll. There necessarily follows a period of several weeks, and often longer, during which the yarn produced from the sliver drawn by that particular roll will not be satisfactory or up to standard. Roughly speaking, this breaking-in period may be regarded as involving two phases. The first phase consists in producing the glaze above referred to on the gudgeons and neck of the roll, while the second has to do with further changes in the journal and bearing surfaces necessary to arrive at such a condition that the roll will run in a semi-dry state. During all of this breakingin period the saddle must be kept well oiled since otherwise the semi-dry running condition never will be attained. A typical length of time for this whole breaking-in period is in the neighborhood of three or four months. After that the vrolls and saddles usually will run satisfactorily for a very considerable length of time, but during the breaking-in period a good deal of nursing of a new roll or saddle, or both, is required.

While the conditions above described have long existed in the textile industry, and their disadvantages have been clearly recognized, they have been regarded as necessary evils and they have been tolerated for that reason. The spinning frame attendants are used to these troubles, they expect them, and know what to do about them. If a saddle cuts too badly or impedes the rotation of a roll too severely. it will be removed and replaced by a new one, and the latter may produce the same results or may run-dn" satisfactorily after a normal breakina-in period. Such a replacement, of course, is always made in the hope that .the latter result will be produced.

With a view to overcoming the manufacturing diiiiculties customarily met in connection with the manufacture' of top rolls from cast iron, it was proposed many years ago to make these rolls of steel. These attempts, however, were not successful. While the expected manufacturing advantages were realized, the operating conditions encountered in using the rolls were so extremely unsatisfactory that it was found necessary to replace them with the orthodox cast iron rolls. This gave steel top rolls a very bad name, and so far as applicant is aware, no attempt to maire rolls or roll bodies from steel has been made since that time.

Notwithstanding this discouraging experience with steel rolls ,and the fact that this attempt to introduce them had prejudiced the trade against the use of them, it seemed to applicant that there should be some way of utilizing the superior manufacturing properties of steel in making articles of this type while still producing a roll that would be as satisfactory in operation as the east iron rolls. It was with this object in view that applicant undertook the experimental work which led to the development of the present invention.

It occurred to applicant that if steel rolls were hardened they might then cooperate with the saddles and cap bars in much the same manner as cast iron rolls and thus avoid the operating diillculties which had proved fatal to the steel rolls previously tried out, as above described. This accordingly was done and several hundred oi' these rolls were put in operation in mills where they could be watched. They were like cast iron rolls in shape, machining and ilnish except that the necks 'and gudgeons were polished more highly, the steel responding readily to this treatment, whereas cast iron does not.

The mill trials of these rolls developed the fact that they possessed operating characteristics far superior to those of any prior art roll.

This was a result totally unexpected and one which could not have been reasonably foreseen.

The nature of these characteristics will .be better understood following a description of a typical roll structure made in accordance with the invention and of the environment in which the roll is used, both of which are illustrated in the accompanying drawing.

In the drawing:

Figure 1 isan angular view of a portion of a drawing mechanism for a spinning frame showing a series of top rolls made in accordance with this invention;

Fig. 2 is a vertical, sectional view on a small scale through the set of drawing rolls and also illustrates a weighting mechanism cooperating with them;

Fig. 3 is a side view, partly in section, of a top roll made in accordance with this invention; and

Fig. 4 is an end view of the roll shown in Fig. l.

Referring first to Figs. 3 and 4, the roll there shown comprises a steel body provided at its opposite ends with integral stub shafts or gud- I are scored or roughened, usually by a shallow spiral grooving, to facilitate the adhesive bonding of the felt or cloth cushions, such as that shown at l, which are wrapped around them. These cushions, in turn, are covered with oots 8 and 9 made of leather or other suitable material, the ends of these cots being turned down against the metal in order to seal off the covering material. At the central portion of the roll its diameter is reduced to provide the so-called neck Il upon which the saddle bears. 'I'hree of these top rolls are shown at A, B and C, respectively. Figs. 1 and 2, supported in cooperative relationship to their respective bottom rolls D, E and F. Typical slotted blocks, a, b and c of the cap bar are shown in normal guiding relationship to the gudgeons of the top rolls, and the front and rear saddles I2 and Il, respectively, are illustrated in their usual positions bearing on the necks Il of the top rolls. The operating pressure is applied to the saddles through a common form of weighting mechanism including a stirrup Il, bell crank lever i5 and weight I6, all as illustrated in Fig. 2.

As above stated, the bodies of the top rolls are made of steel and the kind of steel used for this purpose may vary widely. However, the expensive grades, such as tool steel, the so-called nitro-alloy steels, and the like, need not be employed. In fact, for most purposes a soft steel which is free cutting and machines readily is preferred, both because of these advantages and low first cost, and also because rolls made of it can be straightened after hardening with less danger of injury. A cold-drawn Bessemer steel answers these requirements very satisfactorily. Rolls can be made from this material in an automatic -screw machine from long bars of steel by means of automatically-fed form cutters of the type commonly used in this method of production. Consequently, there are no manual chucking, feeding, or tool changing operations and production is correspondingly expedited.

After the machining operations have been completed, the gudgeons and necks of the roll are polished. This operation also can be performed in automatic machines. Usually it Iinvolves a series of steps with different grades of abrasive grit.

The machined and polished rolls next are hardened. While the bodies could be made of a high carbon steel and hardened throughout, it is preferable from a commercial standpoint to use a free-machining steel and to case-harden the rolls. Any one of several hardening processes may be employed, such as the common pack-hardening methods, nitriding, the cyanide process, and others, and the nature of the process used in' a given situation will depend, in some degree, upon the nature of the steel of which the body is made. With Bessemer free-machining steel, I prefer to use the Chapmanizing casehardening process. This is a method well known in industry. It may be regarded roughly as a combination of the nitriding and cyanide processes. With it, a hardened case of ample thickness, say ten-thousandths of an inch, or greater, can readily be produced. The technique is well established, the control of the .process is adequate for commercial operations, and the expense of the process is reasonable. It is preferable to make the case of a thickness equal to at least eight-thousandths of an inch. v

After hardening, the rolls usually are found to be slightly warped because of internalstrains released during the process, and they are therefore put through a straightening operation. 'I'his is easily accomplished with a steel of the kind preferred since by far the greater part of the body of the roll consists of a tough and ductile core, enclosed in a hard case, which itself has a high degree of ductility when made by Chapmanizing. Thus the straightening operation itself is facilitated and the danger of cracklng the surface during this step is minimized.

The necks and gudgeons of the hardened and straightened rolls next are buffed in order to remove all the scratches and to produce an exceptionally smooth and highly polished surface. This operation also can be performed in machines well known to the metal working trade.

If the manufacturing operations are stopped at this point, an exceptionally satisfactory roll, and one having the surprisingly advantageous operating characteristics above referred to, is produced. However, as is well known, highly polished steel surfaces are very susceptible to corrosion., Because a high humidity is maintained in a spinning room, it was apprehended that corrosion of the exposed polished surfaces of the steel roll might occur, and that in such an event some of the advantages of this construction would be lost. Accordingly, various means of protecting these surfaces were considered and experimented with. Among them was an oxidized finish which was found not only to afford the necessary degree of protection from corrosion but which also had the important and unexpected advantage of improving the operation of the roll.

This oxidizing treatment consists in converting the outer film of the polished surfaces, or preferably of the entire surface of the roll, for a substantial depth, say .0002 or .0003 of an inch, or more, into one of the higher oxygen content iron oxides. Chemicals which may be used for this purpose are aqueous solutions of an hydroxidel and a nitrate of different members of the alkaline metal group, such for example, as sodium hydroxide and potassium nitrate or potassium hydroxide and sodium nitrate. I'he preferred method of procedure involves the treatment of the metal pieces in two steps. In the first step a solution of the two chemicals just mentioned in proportions of one part of the nitrate to two parts of the hydroxide are dissolved in water. About six and a half to seven 'pounds of the chemical mixture is dissolved in a gallon of water, and the solution is maintained at a temperature of approximately 285 F. The metal parts are immersed in this bath for a brief period of time, usually from ten to fifteen minutes. They are then transferred to the second step which consists of a similar treatment with a higher concentration of the chemicals. Here, about nine pounds of the chemical mixture is dissolved in a gallon of water and this bath is kept heated to a temperature of approximately 310 F. 'I'he steel rolls are immersed in this second bath immediately after coming out of the first solution and maintained in it for about the same length of time as before, namely, ten to fifteen minutes. They are then removed, washed in hot water, and dried in sawdust, or in any other convenient manner. The first step creates a blackened surface on the steel pieces and this color is deepened and intensified by the second step of the treatment.

The chemical reactions which take place are not known to applicant with absolute certainty but there is a good reason for believing that the outer surface layers of the treated pieces for a depth of from .0002 to .0004 of an inch are converted into iron oxide having either the formula Fea04 or FeaOs. It is believed that it is the latter. In any event, the dimensions of the treat ed pieces are not materially changed by the treatment, their hardness is not affected, the smoothness of the polished surfaces is improved and their coefficient of friction is reduced. Presumably this is due to the conversion of the microscoplc -surface particles of steel into the oxide with a consequent levelling or smoothing action on the surface. In any event, it has been demonstrated in the practical use of rolls made in this manner that their operating characteristics are improved by this surface treatment.

Also, the protection against corrosion, while not sufficient for steel articles designed to be exposed to severe weather cdnditions, is, nevertheless, suillcient for textile rolls which are to be used in a spinning room.

As above stated, rolls manufactured in accordance with this invention have been found to be definitely superior to the best of the prior art cast iron rolls, not only for those reasons Y which might naturallyhave been expected, such for example, as having a more uniform metallic structure, dimensions and finish, but also because they have demonstrated that they possess unexpected operating characteristics far superior to those of cast iron rolls in the following respects:

(l) The breaking-in period is almost completely eliminated. Hard as is the crystalline scale onthe surface of the cast iron saddles and on the walls of the cast iron cap bars, it is not hard enough to cut the case hardened necks or gudgeons of the steel roll sufficiently to materially interfere with the smooth running qualities of the roll, to produce the lag or hesitation above referred to, or to make the roll wear unevenly.

It had not been contemplated that such a result would be produced.

(2) A further and totally unexpected advantage was that the roll covers run much longer without requiring bufling and that their over-al1 life was extended very materially. This result could not reasonably have been foreseen. It is important not only in the saving directly eiected, but also in reducing the number of roll covering operations required in maintaining a given number of top rolls in operative condition over a period of, say, a year, or some other given length of time. A further advantage here, also, is that since the metal bodies are hardened, there is much less likelihood of the rolls being injured in the operations of .removing the old covers and replacing them with new ones.

(3) There is a substantial improvement in the quality of yarn produced due to the fact that the operating conditions existing during the lbrief running-in period are practically as satisfactory as those which obtain during the ilnal s'tage of the breaking-in period with a cast iron roll. This result likewise could not have been foreseen and it was discovered only upon measuring the yard for yard variation in the product coming from spinning frames equipped with these rolls. However, it will be evident from an inspection of Figs. 1 and 2 that if the saddles are cutting into the necks of the top rolls, there necessarily is a severe drag on the rotation of these rolls, and since they are driven solely by friction with the bottom rolls, through the intervening strands of sliver and against the braking action of the saddles and the weight applied to them, even rotation of the rolls cannot be expected. It is also clear now, even thoughnot foreseen, that the rolls produced by this invention provide much better running conditions, both during this initial period of operation andv subsequently.

(4) Still another unexpected result attending the use of these rolls is that of cleanliness. Amazingly little of the fiber and lint alw-ays produced in a drafting operation adheres to the polished gudgeons and necks of the` rolls. It slides off these surfaces and greatly reduces the labor of cleaning. The matter of cleanliness in a 'spinning room is extremely important because of its effect on the quality of the yarn produced. An f -analysis of the labor costs in a textile mill shows that about half of a spinners time is spent in keeping the spinning frames clean, and approximately of this time is spent in cleaning the top rolls. In a yarn millit has been estimated by the mill people themselves in making an analysis of their labor costs, that approximately 18% of the total labor expended in the mill goes for cleaning the top rolls of the spinning and roving frames. Consequently, anything that reduces this labor cost is of great importance to the mill.

It should be understood that the oxidizing treatment above referred to is notessential to the attainment of any of these advantages. It is preferable to finish the rolls in this manner for the reasons above set forth and it has been definitely determined that this ilnish is of advantage from an operating standpoint, particularly during the initial period of use. The reasons for thisv more. favorable action, however, are not clear. The only thing that is known definitely concerning it is the result. It is thought that it may perhaps be due, in some measure, to the smoother surface and in some degree. also, to the tendencyA` of the oxidized surface to hold the very limited supply of lubricant for a longer'period than would a steel surface not so treated. It is definitely of further advantage, however, in protecting the exceptionally smooth and highly polished surfaces produced by the polishing and bumng operations from deterioration due to corrosion which might even be so slight that it could scarcely be detected bythe naked eye but which might be suilicient to cause these surfaces to collect lint and fly.

This application is a continuation, in part, of my pending application Ser. No. 218,427, filed July 9, 1938.

Having thus described my invention, what I desire to claim as new is:

1. A solid top roll for drawing mechanisms of spinning and roving frames comprising a steel body provided with smoothrhardned gudgeons projecting from opposite ends thereof, the surfaces of said gudgeons being converted into an iron oxide of the type having a high oxygen content.

2. A top roll for drawing mechanisms of spinning and roving frames comprising a steel body provided with bosses to receive roll covers and with an intermediate neck portion of reduced diameter connecting said bosses and serving as a bearing for a saddle, said body also having gudgeons projecting from ODPDSite ends thereof,

said gudgeons and said neck portion being smooth, polished and hardened, the surfaces of said gudgeons and said neck portion being converted into an iron oxide having the formula Fez04 or FeaOa.

3. A top roll for drawing mechanisms of spinsmooth, polished and case-hardened, the surfaces of said gudgeons and said neck portion being converted into a smooth, hard film of iron oxide having a high oxygen content and'of a. thickness of one or more ten-thousandths of an inch.

REX A. KETTLEY.

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