US2700314A - Knurling apparatus - Google Patents

Description

Jan. 25, 1955 s. P. WATKINS 2,700,314

KNURLING APPARATUS Filed Aug. 4, 1949 3 Sheets-sheet 1 I lo INVENTOR.

\ STANLEY P. WATKINS HIS ATTORNEY Jan. 25, 1955 s. P. WATKINS KNURLING APPARATUS 3 Sheets$heet 2 Filed Aug. 4, 1949 STANLEY P WATKINS BY 2 7 z y HIS ATTORNEY s. P. WATKINS KNURLING APPARATUS Jan. 25, 1955 3 Sheets-Sheet 3 Filed Aug. 4, 1949 INVENTOR. STANLEY P. WATKINS HIS ATTORNEY United- States Patna KNURLING APPARATUS Stanley P. Watkins, Baltimore, Md., 'assignor to Armco Steel Corporation, a corporation of Ohio 1 Application August 4, 1949, Serial No. 108,461 7 Claims. c1. s-s.1'

My invention relates generally to the production of knurled metal wire stock, and particularly concerns both a new method of knurling stainless steel metal wire stock, and a new apparatus for effecting such knurling.

An object of my invention is to provide stainless steel metal Wire products such as nails, staples, and the like, which are of highly satisfactory holding qualities.

Another object is to provide a method of producing knurled wire stock which is characterized not only by its basic simplicity, but as well, by its rapidity and effia ciency, by the small number of operational steps required, and by its certainty in operation and in results achieved, all in the substantial absence of skilled supervision.

A further object is to provide an apparatus of the general type described, wherein effective knurling of stainless steel metal wire stock is provided,with desiredpattern thereon, which is characterized by its simplicity, its small number of moving parts, the sturdiness and reliability of all such parts in operation, and by its basic economy, both as concerns initial cost, and in subsequent operational and maintenance expense and upkeep, and which functions, inthe substantial absence of skilled supervision, at high operational speeds, and this with certainty of results, and which, at the same time is characterized by long, useful life with minimum interruption from break-down.

Other objects and advantages will in part be obvious and in part more fully pointed out hereinafter during the course of the following description, taken in the light of the accompanying drawings.

Accordingly, my invention may be seen to reside not only in a new product but in the method of producing this product in matters of the several manipulative, procedural and operational steps employed and in the several parts, elements, mechanisms and features of construction of the apparatus and equipment employed, the scope of the application of all of which is more fully set forth in the claims at the end of this specification.

In the drawings, wherein I disclose that embodiment I of my new apparatus which I prefer at present.

Figures 1 and 2 respectively are side elevation and end views of my invention; while Figures 3 and 4 respectively are side sectional and transverse sectional views of the apparatus of Figures 1 and 2;

Figure 5 is a perspective view of one of the flange sep-' arators employed in my'apparatus;

Figure 6.'is a perspective view of'one of the work rolls of the apparatus;

Figure 7 is a'persp'ective view of one of the yokes, for supporting the knurling rolls of my apparatus;

Figures 8A and 813 respectively are side and end views of one of the pressure blocks used in my apparatus for forcing the roll-yoke" and knurling rolls against the wire sto'ck;while Figure 9 is a perspective view of 'a counter-weight lever and associated counter-weight, for impelling the pressure I block of Figure 8 into working position.

Throughout the several views of the drawings, like reference characters denote like parts.

To facilitate a more ready and thorough understanding of my invention, it may be noted at this point that as yet, stainless steel products have by no means received the Widespread acceptance in the field of fastening devices, such as nails, brads, clips, staples or the like, to which they appear to be entitled. And this is true in spite of the fact that it would be expected that the basic are driven.

qualities of these products would admirably adapt them for use in this general field of production. For it has long been recognized that those materials which are in present day use in such manufacture as nails and the like possess certain inherent and characteristic disadvantages which importantly reduce their acceptability for such purpose.

Illustratively, it is well recognized that to adapt ordinary carbon steel wire to the production of nails, brads and the like, particularly those intended for outdoor use, this carbon steel wire stock must first be subjected to a galvanizing process. Not only is this expensive and timeconsuming, requiring as it does, an additional operational step, but as well, fastening devices formed of this material are observed to fault in a number of different manners, as chipping or scratching when being driven, leaving spots or portions of the device open to corrosion with later rusting, and the consequent formation of unsightly rust spots. Particularly are these disadvantages observed in the case of roofing nails, employed for example in holding tile, slate, composition roofing and the like. And, as well, in the case of ordinary headed nails employed for holding down external siding, sheathing, shingles, clapboard, and the like. Similarly, in the other long-employed expedient, where nails are reproduced from copper or bronze wire stock, it is observed that with the passage of time the characteristic green oxide streaks are encountered, discoloring and marring the architectural surfaces.

Now, from the standpoint of resistance to wear stainless steel is an admirable material from which to construct such fastening devices. It is sturdily resistant to substantially all atmospheric attack. Elevated temperatures, with or without a high degree'of humidity, extremely low temperatures, icing, the soot and dirt of the city, and the salty atmosphere of the seashoreto all of these, stainless steel is substantially impervious to attack. Moreover, it has a pleasing appearance. So far therefore, as concerns appearance, immunity to atmospheric attack, and longevity in use, stainless steel possesses highly advantageous qualities.

I find, however, that with repeated wettings and dryings of the roofing, siding or the like under the weather conditions encountered, these fastening devices fail to hold after a short time. This, I attribute to a slight rotting or softening of the wood, or product into which they While such rotting or softening also is undoubtedly encountered with the conventional nail, brad or other fastening devices, these nevertheless hold very much better than the stainless steel nails. And it is my thought on this that there is some accompanying rusting or corrosion which serves to lock with the wood or other product and compensate for the loss of grip arising from the rotting or softening. Of course, however, as noted above, there comes a time when the one, augmented by the presence of the corrosion product, exceeds the other and the fastening fails completely. 7

Thus consider the nailing down of roof shingles. The nails used for this purpose commonly are about an inch in length. Yet they are required and are designed to hold the roofing securely in place while at the same time stopping short of completely piercing the underlying sheathing. Despite this short length and despite the small depth to which these nails penetrate, they are required to withstand not only the lifting pressures of accumulated ice and snow, but as well, the lift of high winds and the expansion occasioned by heat and cold. Ordinary nails" of the type generally described at first, and when initially installed, are satisfactory for this purpose. Failure of the galvanized coating in the case of coated carbon steel wire, however, and the passage of time alone, in the instance of bronze and copper wire, will shortly give rise to detrimental staining and rusting and eventually will be accompanied by mechanical failure. If recourse could be had to the use of stainless steel stock, these disadvantages would be suppressed or entirely avoided. But I findthatstainless steel fastening devices are not acceptable for this purpose.

Accordingly, an object of my invention is to overcome the inadequacies of the prior art and provide fastening devices of stainless steel which are strong, tough, corrosion-resistant and yet well adapted to strongy hold under (h G the various conditions encountered in actual practical use for great lengths of time. And a further object of my invention is the provision of apparatus for imparting holding qualities to stainless steel wire stock.

And. now referring more particularly to the practice of my invention, I impart to the wire stock a particular surfac in fact a knurling comprised of uniform indentation of the stock by a multitude of small impressions disposed in a sweeping spiral of wide pitch. 1 find that the. metal bordering each such indentation is, slightly raised above the surface of the metal, due to the 'flow of metal created by the individual indenting elements, enhances the holding effect. In other words, I thereby create a roughened surface imparting substantially improved holding power. Viewed from another angle, the holding effect of my new product is achieved in threefoldimanner. First, by the existence of the slightly raised borders of the indented portion, .second, by the indentations themselves, which permit the entry of the material into which they are driven, 'into their numerous interstices, and third, by the effect of the spiral, which, to a certain degree at least, acts as a sort of flattened thread of 'wide pitch, say about one turn to an inch.

While many modes of generally achieving knurling are available, and although many apparatus and 'machines exist for imparting knurling to wire stock, I find that for one reason or another, these methods and available apparatus are unsuited for imparting knurling to stainless steel stock wire stock. Accordingly, I have devised a new method and apparatus.

, Thus referring more particularly to the embodiment of my apparatus as shown in the several views of the drawings, it will be seen (Figures 1 and 3) that my new machine comprises two fundamental parts, namely, a fixed or guide part, and a second or revolving head part. The function of the guide mechanismis to lead the wire stock to the revolving head and to make the same available to the revolving head in accordance with the demand of the latter. At the same time the guide rolls serve to clamp the wire stock firmly against, and to resist completely,

all tendency of the wire stock to twist about its axis under the influence of the knurling rolls of the revolving head. On a suitable support common to all parts of the new machine, I provide a housing 11, in which I mount suitable paired guide rolls 12 and 13 (Figure 3). Bolts 14 serve to hold down the housing 11 against the base plate 10. These rolls are disposed with axes parallel to each other, and transverse to the axis of the metal wire stocklS, Figure 3. The guide rolls 12, 13 are grooved to permit the passage of the wire stock, and the size of these grooves is dependent upon the diameter of the wire to be processed. When the size of the wire is to be changed materially, then the guide rolls are changed to ones having width and depth of groove closely conforming to that of the wire stock now to be processed. Where the change in the wire stock is not appreciable, no such change in guide rolls is required. Suitable bearings, conventional in the art and not here shown, are disposed in the housing 11, and carry the rolls 12, 13 for idle rotation therein. Thus, the rolls are so designed as to be free, to revolve as the wire is pulled through the machine. No power or driving impulse is imparted by the guide rolls.

In the present embodiment the lower roll 13 is fixed asjto its vertical height. The upper roll 12, however, is

designed so as to be raised or lowered, for convenience in feedin he wire throuch the grooves in the wires. or for controlling the pressure of the rolls on the wire stock. To this end, I provide a threaded rod 15 and handle 16 for raising the upper guide roll 12. It is ofcou rse entircly practical, where desired, to construct both rolls for vertical movement. For all practical pumoses, however, it is sufficient only that the upper guide roll 12 be susceptible to raising and lowering, The-function of these guide rolls 12, 13 is two-fold. Firstly, they guide the coil of wire to the revolving knurling head to be described. Secondly, these guide rolls securely grip the wire stock so that it cannot turn about its axis and twist after introduction into the knurling head. The necessity of this restraint against twisting is ap arent when it is considered that the action of the knurling mechanism is to twist the wire progressively as the latter passes through the knurlingh'ead. Thus, without the restraint resulting from the gripping of the wire stocksecurely-between the guide rolls, in the grooves of} the latter, the wire stock, as it. is fed-through to the. knurling head and" advances in 4 its passage, is found to become severely twisted, and in many instances badly snarled and kinked.

From the guide rolls the wire stock is drawn into the fundamental part of my new machine, the revolving head. This revolving head is indicated generally at 17 (see also Figure 4). This head is a composite mechanism constituting in part two parallel disc- like plates 18 and 19. The plate 18 is disposed adjacent the guide roller housing 11. It is fast .ona spindle 20, which itself is mounted on a standard anti-friction bearing 21, such, by way of illustration, as the bearing now available on the market, as Dodge Type 'SC. The bearing 21 is removably carried, by suitable means as lock-down bolts and nuts 22, on a standard 23 Welded or otherwise made fast to the base plate 10.

Spindle 29, which is hollow (Figure 3), and has a construction hereinafter described, is termed the wire inlet spindle for the reason that, being adjacent the guide rolls 12, 13, it first receives the wire stock into the revolving head 17. Similarly, the face plate 19 is carried on a spindle 24 which is turn carried in a suitable antifriction bearing 25 similar in type to the bearing 21, and iusimilar manner is made fast by suitable removable and releasable hold-down means, such as headed bolt 26, on a supporting '.pedestal27 carried on the base plate '10. Thus, the spindles 20 and 24, together with the head plates 18,19, arerevolvable in the bearings 21, 25. The spindle 24, hollow in manner similar to the spindle 20, is known as the wire exit spindle, for the reason that it is located on that side of the revolving head which is remote from the guide rolls 12 and 13, and accordingly is that spindle through which the wire stock last passes in its passage through the revolving head.

As I have stated, these spindles 20 and 24 are hollow in an axial direction (Figure 3), and I provide hollow inserts or guides 20A and 24A therefor, which are interchangeable amongst each other, and which have central passages of different diameter,-for the accommodation of wires of different sizes. The center line of the hollow portions of the guides is set on the exact axis of thespindles 20, 24 so that the hollow guides serve to align the travelling wire 15 in the exact center of the revolving head 17. Conveniently, these guides, termed respectively inlet and exit guides, depending upon which spindle they are located in, are formed of hardened tool steel, the better'to withstand the abrasive action of the rapidly moving wire stock.

As I have stated, the plates 18, 19 are here attached directly and made fast to the spindles 20, 24 or are formed as integral partsthereof. They comprise two circular head fiangesand form the 'side of the circular head and provide support for the working parts of this head. Metal separators 28, 29, best shown in Figures 1 and 4, serve to separate the- head flanges 18, 19 at proper working distance from each other. Although these separators 28, 29 may be of any desired shape and dimensions, they are here shown as being of segmental shape in plan, having an appreciable massand thickness, and being approximately 2% inches wide. They serve, as best shown in Figure 4, to separate the counter-weight levers and pressure blocks, later to be described-at a proper distance from each other.

The moving parts comprising the mechanism of my new apparatuscomprises a number of essential elements which effectively cooperate with each other to achieve the desired operation. Having referencev to Figure. 3, it will be seen that the wire stock 15 emerges from the hollow guide 20A'within the spindle-20 into the path of the work rolls, here shown at 31, 32. These work rolls are carried on suitable bearings '33. which in turn are carried in work roll yokes 35. These yokes are carried' by pressurewblocks' 36, which in turn, are forced in a generally radial direction inwardly towards the" wire stock, We counter-weight lever indicatedgenerallyat '37 and the. centrifugal action of which is controlled sensitively by means of a cooperating counterweight '38.

The spindle 24 is extendedv through the bearing 25 and terminates exteriorly thereof on the outer side thereof. from the head'flange 19. Suitable means are provided for powering thepower shaft thus provided by the extended spindle 24. While this may take any suitable and conventional form. such as gearing or the like, I here conventionally show the same as comprising a pulley 39 having a V-shaped groove 41) therein and'whichpulley is made fast to the shaft 24 by suitable means such as a set screw 41; It is by no means necessary that the groove 40'- he of V- or A-section but it is here so shown because of the improved power take-off properties inherent in pulleys of this general type. Any suitable means may be employed for powering the pulley 40, but as here shown, this comprises a belt 42 shown in Figure 2 which is impelled by a suitable electric motor 43, the base 44 of which is carried on the common support 10. Conveniently, this may have a rating of one-third horsepower, capable of operating at say 1725 R. P. M.

Considering now more particularly the revolving head 17 (see Figures 3 and 4), the working rolls 31 and 32 are conveniently formed of hardened tool steel, having illustratively, a hardness by Rockwell test, C58-60. As perhaps best shown in side elevation in Figure 6, these rolls may typically have a one-inch diameter with an approximate length of one and one-half inches. Thus they have generally the shape of an elongated cylinder. These dimensions are not extremely critical, and the sizes may be increased or decreased within reasonable limits. It has been my experience, however, that rolls of smaller diameter do not function as well as the larger rolls, they tending to throw off center the wire undergoing treatment.

- In the typical embodiment disclosed, I mill the work.- ing surface of the rolls 31 and 32 with rightand lefthand grooves. These grooves I form in the shape of sharp Vs, using for that purpose a 90 cutter. I dispose these rightand left-hand grooves so that they will cross in such manner as to form sharp, diamond points. Further, I dispose the grooves so that they will possess an 0.038 inch position normal to helix and with a three inch lead, having a 573l helix angle. Conveniently, I cut the grooves to a depth of 0.019 inch. Of course, however, other types of grooves may be employed, for achieving a variety of different patterns, all falling within the ambit of my invention.

In the foregoing I have described how the rolls 31, 32 are mounted in suitable bearings, and are thereby carried for rotation in the yoke 35. This yoke 35, details of which are shown in Figure 7 is one of a pair of such yokes, there being one provided for each work roll 31, 32, respectively. Each such yoke 35 comprises paired and parallel extending leg portions or cars 39, 39; and each such ear portion 39, 39 bears, on a common axis, holes 40, 40 for the reception of the spindles 33, 33 on which the work rolls are mounted. From the central web 41 of these yoke members 35, 35, there extends axially and centrally, and rearwardly thereof, a spindle 42, made fast in any suitable manner to the body portion of the yoke. Now, this pin is disposed perpendicularly to the axis of rotation of its cooperating work rolls 31, 32 and it rests in a recess in the adjacent pressure block 36. The rotatablenature of the pin or spindle 42 permits the yoke 35 to be rotated as required, in order to adjust the angle of the work roll 31 relative to the wire 15 being knurled.- To this end, I provide a recess 43 diametrically across, the free end of the spindle 42, to participate in the angular calibration of the work roll yoke 35.

The pressure block 36, as previously noted, is'disposed between the working end 45 (Figure 4) of the counterweight lever 37 and the head 41 of the yoke 35. This block 36 is of the form shown in Figures 8A and 8B and has a central opening 46 passing through the body portion 47 thereof, for the reception of the spindle 42 of the roll yoke 35. Each pressure block 36 has in addition to' the body portion 47 thereof, an upper, winged portion 48 which is both outwardly and laterally flaring, as at 48A, and is rearwardly extending as at 48B. The overhang thus provided serves effectively as a bearing surface against the bottom faces 28A and 29A of the cooperating flange separators 28 and 29. A retaining pin 49 (Figures 3 and,4) extends between the adjacent head flanges 18 and 19 and serves as a bottom abutment for each of the pressure blocks 36. The contact then of the upper surface of the plane portion 48 of each pressure block 36 against the bottom face of the flange separator, and the contact of the outer face 47A of the body portion 47 ofthe pressure block 36 against the working head 45 of the counterweight 37, and the contact of the bottom'face 47B- of the body portion 47 of the pressure block 36 against the pin 49 cooperate to maintain the pressure blockin its proper and operable position.

'- It is apparent (see Figures 7 and 8B) that the spindle 42 of the yoke 35 is longitudinally movable in'the open ing' 46 provided in the pressure block 36, and that as well, it is rotatable therein. Accordingly, this permits adjustment of the yoke 35 and the particular roll 31, 32 carried thereby within the pressure block and relative to the wire stock 15. In use, the roll is first adjusted to the proper angle for optimum knurling (Figures 1 and 3), and like wise is moved bodily relative to the pressure head (Figure 4) so that in operation, it will bear against the wire stock to the desired extent. Two adjustments are thus seen to exist, one rotational, and the other lengthwise.

To facilitate the rotational adjustment, use is made of the recess 43 in the free end of the spindle 42 (Figures 1 and 7). A screw driver or the like is employed to rotate the spindle 42;-and to facilitate nicety of angular adjustment, the outer vertical face of the pressure block body portion 47 is'inscribed as at 47C (Figure 8B), so that the diametrically disposed recess 43 will line up with the said graduations 470 as the spindle is rotated relative to the pressure block 46. Similarly, to obtain the longitudinal adjustment, the yoke 35 is moved back and forth in the bore 46 within the pressure block 36 until the proper adjustment is achieved. At that time a lock nut or set screw 50 (Figures 4 and 8A) is threaded down through the side of the body portion 47 of the pressure block 36 until it is fast against the spindle 42. In this manner, the rolls 31, 32 along with their supporting yokes 35, 35 are made fast against movement and in operating position relative to the wire stock 15.

It will be seen from the foregoing that because of the constraining influence of the faces 28A and 29A of the flange separators 28 and 29 respectively and the retaining pins 49, the pressure blocks 36 are constrained to limited movement in a horizontal and axial direction as shown in Figures 3 and 4. This horizontal movement is controlled by the working head of the control lever 37 under the influence of the counter-weight 38. Because of the latitude in machining which may well be required in the design of the pressure block 36, I provide between it and the head of the yoke 35 a suitable shim A formed of steel, and fitting loosely yet nicely about the spindle 42 of the said yoke 35. The number and width of shims may be varied as desired, in accordance with experience.

Pressure block 36, as also previously noted, is under the control of the lever 37. This lever has elongated arc-like or crescent form and is pivoted near its working head 45 on a shaft 52 (Figure 4) which extends between the head flanges 18 and 19, being received in a facing portion therein disposed slightly below the horizontal center line of the apparatus in the case of the left-hand lever 37 in Figure 4 and at an equal distance above the horizontal center line of the apparatus in the case of the righthand lever 37 as shown in Figure 4. As best disclosed in Figure 9, this counter-weight lever 37 has a hub portion 37A which is of substantial width, and which at the same time is less than the space provided between the head flanges 18, 19. At its head end the crescent-shaped counter-weight lever 37 is bifurcated into forked head portions 45A, 45B. These bifurcated pressure arms bear against the pressure blocks 36, 36, against the recessed faces 47A thereof, and tend, when the revolving head is in-motion, to force the pressure head yoke 35. and work roll of 31, 32 against the wire stock. Washers 53, 53 (Figure 1) are disposed about the shaft 52 between the counterweight lever 37 and the head flanges 18 and 19, soas to avoid tendency towards lateral movement of the counter-weight lever 37 across its supporting shaft 52 and consequent frictional stresses attendant thereupon. A set screw 54 serves to make the counter-weight lever 37 fast on the shaft 52.

Each counter-weight lever terminates in an elongated curved or crescent shaped blade portion 37B on that side of the pivot point 52 opposite the working head 45, 45. thereof. This portion 37B of the counter-weight lever terminates in a slanted, plane face 37C (s ee also Figure 9) which is adapted to abut against but to be freely movable relative to :the adjacent face of the flange separator in Figure 4. Each counter-weight 38 is made fast by means of a set screw 38B at an adjusted position along the length a of the counter-weight lever arm 37A. To facilitate adjustment of the counter-weight along lever arm 37A so as to set the'same according to given pr ssures ofthe work rolls at specific rates of rotation of the entire working head, suitable inscriptions 37D are provided along the length of this crescentportion 37B.

Asdisclos'ed, the counter-weight 38 has an internal bore 38C of rectangular section complemental to the cross sectional contour of the counter-weight lever arm 37A. This constrains the counter-weight against rotation about the lever 37.

It is apparent from the foregoing (see also Figure 4) that the several working parts heretofore described exist in pairs. For symmetry and for equalization of stresses. and strains, the elements of each pair of working parts are disposed in generally diametrical opposition to each other, on opposite sides of the revolving head. This construction is such that when the working head rotates about its axis on the hollow spindles 20, 24, the countenweights 38, 38 are thrown outwardly by centrifugal force. The pivoted lever arms 37, 37 transmit this impelling force couple, through working heads 45, 45, inwardly against the pressure blocks 36, 36. This inward force is transmitted directly to the yokes 35, '35 and thence to the working rolls 31, 32. These working rolls are thereby forced with considerable pressure against the wire stock which passes between them. The pressure, the adjustment of which may be varied by the position of the counter-weight 38 along the arm 31 8, by the width and number of shims 50 between the pressure block 36 and the yoke 35, and by the longitudinal and rotational adjustment of the yoke relative to the pressure head 36, is sufiicient to bring about the desired indentation of the wire stock.

The skewed position of the rolls 31, 32 is sufficient to create a spiral knurled pattern on the wire stock. Moreover, the pattern of the knurling rolls and the skewed position in which these rolls are mounted serves to pull the wire through the machine as an incident to rotation of the rollers. In other words, the knurling action brings about self-feeding of the wire stock.

I control the rate of the feed of the wire stock by the control of the amount of skew of the indenting rolls, and by the rate of rotation of the working head (the speed of the motor 4-3 and the ratio of driving and driven pulley diameters). I find it entirely feasible to vary the degree of skew in accordance with both the indenting pattern desired and with the desired pitch of the spiral pattern. Typically, however, I achieve excellent results when the knurling rolls are set at a skew angle to the axis of the wire stock of about 42 /z. Changes in this angle vary the pitch distance, and opens or closes the indented pattern. as desired. In this connection I have achieved successful knurling within a skew angle range from about 10 to about 80. I prefer, however, that the skew angle be within the approximate range of about 40 to As I have stated hereinbefore, the spindle 24 has fast thereto the pulley 41 connected by bolt 42 to the electric i motor 43. This was stated, however, as being merely typical, and I further suggested that any desired and conventional system of rotating the head 17 could be employed, as desired. Moreover, this head may be rotated at a variety of speeds, provided only that counter-weight adjustments be made to insure proper working pressures. illustratively, I have found a rotational speed for the work ing head of 3500 R. P. M. to be satisfactory for the machine undergoing description. At this speed and under these operational conditions, I find roll pressures of approximately 1000 pounds per squareinch to be necessary to indent fully, cold-drawn steel wire of composition l8 parts chromium to 8 parts nickel.

In the practice of my invention, and as more clearly illustrative of the method features thereof, 1 provide coils of stainless steel wire stock, placed conveniently on a take-off reel. Preferably, I lead the wire stock from the take-olf reel through a lubricating bath to minimize deterioration of the guides. Very little lubrication is required. and if desired this lubrication may be dispensed with. However, I find'that the slight film of oil pro ided on the wire stock by wiping the wire through one or more folds of felt or cloth is helpful in reducing deterioration, and in prolongiru appreciably the life of the apparatus. Thewire stock,thus lubricated. is then fed through the inlet groove of the guide rolls 1!, 13 into the orifice of the inlet spindle guide 2% and thence between the opposed and skewed knurling rolls 31, 32. Thence it passes through the exit spindle guide 24 to take up reel, not shown.

Once the wire has thus been led loosely through'the machine, and before the revolving head hasbeen'set into rotation, the guide rolls 11, 13 are adjusted by tightening down the spindle 15 (Figure 3) by the hand wheel 16. In this manner the wire isgripped firmly in the central groove of the guide rolls sufficiently tightly so as to restrain the wire stock against twist, but not so rigidly as to hamper the free longitudinal passage of the wire stock through the guide rolls. The working rolls 31, 32. are skewed to the desired angle by adjustment of the yoke spindle 42 through its recessed head 43 relative to the graduations 47C present on the pressure block 46, making use of the engraved lines on the base of the yoke pin and on the back of the pressure block. In this connection, care must be observed that the angle of adjustment relative to the axis of the wire stock E5 is the same for each working roll 31, 32. For if this is not done, the forces exerted by the opposed rolls 31, 32 will not be equal. Not only will a distorted pattern be obtained on the wire stock, but moreover, the wire is subjected to uneven strains resulting in distortion of the wire. strains becomes aggravated by the degree of discrepancy between the settings of the two knurling positions.

Nextly, the counter-weights 38 (see Figure 4), similar in weight and dimensions, are set in like positions on their respective lever arms 37.3. The motor 43 is started into operation and the head 17 is rotated at desired rotational speed, typically 3500 R. P. M. .As the counter-weights 38 fly outwardly, carrying with them the crescent-shaped lever arms 373, the counter-weight levers 37 rotate about their pivot spindles 52, so that the working heads, 45 thereof bear, by their bifurcated portions 45A, 45B, in the recesses 47D, 47D provided in the pressure block 36, andforce the yokes 35 and work rolls 31, 32 against the metal wire stock 15. As the work rolls move inwardly and engage the wire stock, the spiralling relation of the skewed rolls relative to the wire pulls the wire through the machine, and this action proceeds until the coil is exhausted. Fresh coils of wire stock may be knurled without further regulation of the apparatus except the requirement of repositioning the guide rolls as each new coil is started. If the wire stock is of substantially uniform diameter, this becomes unnecessary.

Thus, in accordance with my invention, I have processed through a coil of cold-drawn 18% chromium, 8% nickel stainless steel wire of 0.086 inch diameter. This wire was knurled in an indented spiral design in a machine according to my invention at a head speed of about 3509 R. P. M. The working rolls drew the wire through the revolving head at a speed of 45 feet per minute. The product, a wire of the character heretofore described in this specification, was then fabricated without difficulty into 1 /2 inch headed nails, in a standard nail machine. Tested in asbestos shingles, the nails exhibited holding powergreatly in excess of the tenacity offered by standard siding nails formed of similar material, the holding qualities being ample to satisfy all the requirements of the art.

And it will be seen from the foregoing that, in accordance with my invention, it is possible to produce metal wire stock of stainless steel 'and generally similar refractory metals which can be fabricated into metal fasteners displaying a high degree of tenacity even when heavily loaded while existing in short operational lengths. Also that I have provided both a method and apparatus which are simple in themselves, economical of production and in operation and maintenance, and in which the machine displays long useful life with certainty in operation, and which can be adjusted for varying operational conditions with-a minimum of supervision and attendance, and

which produces a wide variety of patterns on the metal Wire stock. Both the method and the apparatus are sufficiently rapid to permit successful entry into the highly competitive field of producing metal fasteners, and to permit the combination for the first time of the well recognized and highly desirable'qualities of stainless steel wire with tenacious holding qualities. All these and many others, highly desirable objects and advantages, attend upon the practice of my invention.

Since many embodiments of my invention will suggest themselvesto those skilled in the art, once the broad .aspects are disclosed, I intend the foregoing disclosure to'be construed merely as illustratively and not by Way of limitation.

I claim:

1. A machine for'knurling metal wire stock, comprising, in combination, guide means for directing the wire stock towards a revolving head while restraining the wire against twisting, and a revolving head through which the wire stock passes having knurling means thereon means for establishing the force with which the knurling element The severity of these thereof is applied against the wire stock, means establishing the skew angle of the knurling means relative to the wire stock, and means responsive to and proportional to the speed of revolution of said revolving head for compelling said forcing means against the wire stock.

2. A machine for knurling metal wire stock, comprising, in combination, guide means for guiding the metal wire in its linear path towards a revolving head and for restraining the wire against twisting, and a revolving head into which the wire stock feeds from the guide means, said revolving head comprising paired knurling rolls disposed on opposite sides of said wire stock, holders for said rolls in which the latter are rotatable, means for forcing said roll holders bodily towards said wire stock, speed-responsive means for compelling said forcing means towards said wire stock as an incident to and proportional to the speed of revolution of said revolving head, and means for revolving said revolving head.

3. A machine for knurling metal wire stock, comprising, in combination, guide means for guiding the metal wire 1n its linear path towards a revolving head and for restraining the wire against twisting, a revolving head into which the wire stock feeds from the guide means, and means fast to said guide means for revolving said revolving head, said revolving head comprising paired knurling rolls disposed on opposite sides of said wire stock, holders for said rolls in which the latter are rotatable, means for forcing said roll holders bodily towards said wire stock, speed-responsive means for compelling said forcing means towards said wire stock, as an incident to and proportional to the speed of revolution of said revolving head, inlet and outlet guide trunnions for said revolving head through which the wire stock passes in its passage to and from the revolving head.

4. A knurling machine for stainless steel wire stock,

comprising a base plate, bearing standards extending upwardly from said base plate, a revolvable head having hollow spindles rotatably carried in said bearings and through which hollow spindles the wire stock passes,

means fast to one of the spindles of said head whereby rotational force may be imparted to the revolving head, and means for rotating the revolving head, said head com prising side members fast to said inlet and outlet spindles, paired counter-weight levers and cooperating adjustable counter-weights thereon, carried between said side members and responsive to centrifugal action, separating elements disposed between said side members and said counter-weight levers, pressure blocks disposed between the working head of each said counter-weight lever and the adjacent separator element, means extending between said side members and cooperating with said counterweight levers and said separator elements for constraining said separator elements for movement in a radial direction towards and away from the wire stock passing centrally through the axis of said revolving head under the impelling action of said counter-weight levers, a knurling roll yoke carried one in each said pressure element and longitudinally and angularly adjustable thereto, a knurling roll mounted for rotation in each said yoke for knurling the metal wire in a spiral pattern, the variation in the rotational speed of said revolvable head, in the position of the counter-weights along the counter-weight levers, and in the longitudinal and angular adjustment of the roll yokes relative to the pressure blocks bringing about corresponding variations in the knurled pattern on tthe wire stock, in the pitch of the spiral pattern produced thereon, and in the linear speed of the wire stock through the revolving head.

5. In knurling apparatus for metal wire stock, a revolving head comprising in combination, centrally bored mem bers, anti-friction bearings supporting the same for axial rotation, diametrically opposed and paired counter-weight levers pivotally carried between said members, spacing members also carried between said members and disposed between said counter-weight levers, paired pressure blocks in said revolving head carried loosely between said spacing members and said counter-weight levers and adapted to be forced inwardly by said levers, roll yokes rotatably carried one by each of said pressure member, and knurling rolls carried in said yoke members, the said yoke members being adjustable both longitudinally and angularly relative to said pressure blocks.

6. A revolving head for knurling metal wire stock, comprising in combination, two centrally bored members, a support for the same including anti-friction bearings,

; diametrically opposed and paired counter-weight levers pivotally carried between said members, and having adjustable counter-weights thereon, spacing members also carried between said two members and disposed between said counter-weight levers, paired pressure blocks in said revolving head carried loosely between said spacing members and said counter-weight levers and being constrained thereby to linear motion towards and away from said wire stock under the impelling action of said counterweight levers, roll yokes rotatably carried one by each of said pressure member, and knurling rolls carried in said yoke members which said yoke members are adjustable both longitudinally and angularly relative to said pressure blocks, and means for rotating said revolving head, said yoke and pressure blocks having graduations thereon for facilitating angular adjustment of the yoke relative to said pressure blocks.

7. A revolving head for knurling metal wire stock, comprising, in combination, a pair of centrally bored members, a support for the same including anti-friction bearings, diametrically opposed and paired counterweight levers pivotally carried between said members and having counter-weights adjustable along the length thereof with graduations thereon for facilitating the adjustment of the counter-weights, spacing members also carried between said pair of members and disposed between said counter-weight levers, paired pressure blocks in said revolving head carried loosely between said spacing members and said counter-weight levers and being constrained thereby to linear motion towards and away from said wire stock under the impelling action of said counter-weight levers, roll yokes rotatably carried one by each of said pressure member, and knurling rolls carried in said yoke members, the said yoke members being adjustable both longitudinally and angularly relative to said pressure blocks, and said yoke and pressure blocks having graduations thereon for facilitating angular adjustment of the yoke relative to said pressure blocks.

References Cited in the file of this patent UNITED STATES PATENTS 60,067 Sanford Nov. 27, 1866 145,285 Dudley Dec. 9, 1873 204,149 Heckmann May 28, 1878 206,688 Richardson Aug. 6, 1878 234,222 Atwood Nov. 9, 1880 318,566 Jones May 26, 1885 413,625 Moore Oct. 25, 1889 415,880 Patt Nov. 26, 1889 455,336 Johnston July 7, 1891 855,658 OBrien June 4, 1907 960,769 Armstrong June 7, 1910 1,365,386 Djidics Jan. 11, 1921 1,394,716 Davies Oct. 25, 1921 1,546,091 Lewis July 14, 1925

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