US2251681A - Wear-testing fabric and other materials - Google Patents

Description

I 1941- E. F. H ATHAWAY EIAL 2,251,6 1

WEAR-TESTING FABRIC AND OTHER MATERIALS Filed Nov. :50, 1937 10 Sheets-Sheetl 1941- r F. HATHAWAY ETAL ,251,681

WEAR TESTING FABRIC AND OTHER MATERIALS I Filed Nov. 30, 19:57 1o sheets-sheet s 1941- E. F. HATHAWAY ETAL 2,

WEAR-TESTING FABRIC AND OTHER MATERIALS Filed Nov. 30, 1937 l0 Sheets-Sheet 4 EdgrarFHmway 770224 428 12111127 M flak? 10m @3 3 6 .6 Ms M 1 h. mm H 5w 7, v 1 I r0 5 E a m Aug. 5, 1941. E. F. HATHAWAY ETAL WEAR-TESTING FABRIC AND OTHER MATERIALS Filed Nov. 30, 1937 10 Sheets-Sheet 5 8 RRARRRQ h V m R 7 \Q Aug. 5, 1941. E. F. HATHAWAY ETAL WEARTESTING FABRIC AND OTHER'MATERIALS Filed Nov. 30, 1937 10 Sheets-Sheet 6 W .Baw b 2 3w? 1941- E. F. HATHAWAY ETAL WEAR-TESTING FABRIC AND OTHER MATERIALS 1o Sheets- Sheet 7 Filed Nov. 30, 193'? eco so? e06 804 Edgar? Waiie? Barby,

8 1941- E. F. HATHAWAY ETAL WEAR-TESTING FABRIC AND OTHER,MATERIALS Filed Nov. 50, 1957 10 Sheets-Sheet 8 I, s a;

kiga Aug 5, 1941. E. F. HATHAWAY ETAL WEAR-TESTING FABRIC AND OTHER MATERIALS l0 Sheets-Sheet 9 Filed Nov. 30, 1937 6 w w 7 m 7 7 w a W Barb y Aug.5, 1941- E. F. HATHAWAY ET AL WEAR-TESTING FABRIC' AND- OTHER MATERIALS Filed Nov. 30. 19s? I 10 Sheets-Sheet l0 asa Patented Aug. 5,1941

WEAR-TESTING FABRIC AND OTHER MATERIALS Edgar F. Hathaway, Weliesley, and Walter Bixby,

Dorchester, Masa, assignors to Shawmut Enginearing Company, Dorchester, Mass'., a corporation o! Massachusetts Application November 30, 1937, Serial No. 177,376

19 Claims.

Our present invention relates to testing the wearing qualities of various sheet materials such as fabrics, webbing, floor coverings and others, by efiecting wear on them analagous to that expected in actual use. In various respects the invention presents improvements over that oi our copending application Serial No. 757,358 filed December 13, 1934, now Patent No. 2,100,332, and as to all common subject matter the present application is a continuation-in-part of said earlier application.

In the drawings illustrating by way of example certain embodiments of the invention,

Fig. 1 is an elevation of the upper portion of one form of the wear testing apparatus;

Fig. 2 is a similar view showing the immediately lower portion of the apparatus, including the support for the specimen, the wearing element and the wear measuring instrument, Fig. 2 being in eflfect a downward continuation of Fig.

Fig. 3 is a vertical section, on a smaller scale of the lower portion of the apparatus, including the cabinet base and its movable mounting, the receiving end of the dust-collecting system, and showing the general arrangement of the operating and control mechanism;

Fig. 4 is a vertical section through the dust receptacle of Fig. 3;

Fig. 5 is a horizontal section on the line 5-5 of Fig. 11;

Fig. 6, on a similar scale as Figs. 1 and 2, is

a plan of the specimen-holding platen and the releasable means for securing the specimen there- Fig. 7 is an enlarged vertical section as on the line l-l of Fig. 6, with the clamping means in an intermediate position as during the installa tion or removal of a specimen;

Fig. 8 is a view similar to Fig. 7 but with the specimen fully installed;

Figs. 9 and 10 are -fragmentary views corresponding to portions of Figs. 7 and 8 illustrating the securing of different types of test materials on the platen;

Fig. 11. is a vertical section on the lines Illl of Figs. 1 and 2; v I

Fig. 12 is a section corresponding to the upper portion of Fig. 11 but taken at right angles to the latter;

Fig. 13 is an enlarged vertical section through certain valve mechanism associated with the suction gauge;

Fig. 14 is a sectional view of the venting or bleeder valve;

Fig. 15 is a view of the mounting means for the electric contact finger of the stop mechanism;

Fig. 16 is a. wiring diagram of the several electric circuits associated with the apparatus;

Figs. 1'7 to 21 inclusive'are bottom plan views of various forms of wearer head or shoe for alternative use under different test conditions;

Figs. 22 and 23 respectively are a side elevation and a top plan of a thermostatic control associated with the wearer head;

Fig. 24 is a vertical section of a wearer head or shoe equipped fluid cooling means;

urements at different times, wherein Fig. 29 is a view partly in plan and partly in horizontal section taken as if looking down on the line 29-29 of Fig. 3, and on a larger scale,

Fig. '30 is a view, mainly in elevation, of the mechanism of Fig. 29 as seen from a position below said figure,

Fig. 31 shows a portion of the mechanism of Fig. 30, as it viewed from the right and in a vertical section along line 3l3l or said Fig. 30, and

Fig. 32 is an exploded view of a timing unit seen in Figs. 29 to 31.

The apparatus as herein illustrated is of the same general design and arrangement as in said copending application. It includes alower supporting portion comprising suitable framing and an enclosing cabinet I, see particularly Fig. 3, in which the main operating parts are housed. As in the previous application the device as a whole may be set on wheels or castors for readily shifting it to various points of use. Supported on the framing and closing in the top of the cabinet I is a table or platform 2, Fig. 2, on or about which the wearing, measuring and recording instrumentalities are disposed. It will be noted that Figs. 1 and 2 are views looking at the apparatus from one corner of the base portion.

The fabric or other specimen to be tested is secured flatwise on a platen or specimen-holder 3 above and substantially central of the platform 2 and supported for movement in its own horizontal plane in a similar manner as in the preceding.application. In view of the full disclosure in said application it is sufllcient for present purposes to note that the platen 3 as a whole receives a sinuous movement in a closed path, this movement being compounded of that of a crosshead which is movable on guides on the platform 2 in one and the reverse directions, and which in turn supports the platen for movement at right angles relatively to the crosshead. These relative movements and the total resulting compound movement of the platen are produced by cam mechanism in the base portion similarly as in the previous case.

In the present instance the platen or holder in its entirety comprises in addition to the block, anvil or platen proper 3 on which the specimen is placed, a relatively large, heavy, laterally extended base portion 4 to which the block or platen proper 3 is detachably secured as by screws 5 at its corner portions; see Fig. 6. This base portion 4 is of substantial thickness, particularly throughout its peripheral portions, as clearly seen in Fig. 2, so that it contains a considerable mass of the metal or other material of its composition and accordingly possesses a substantial inertia and is not readily subject to vibration. This heavy base portion of the specimen holder is symmetrically disposed relative to the platen 3 and is centrally apertured, and recessed at its under face to accommodate the operating connections such for example as illustrated in the earlier application.

As partially shown in Fig. 3, sufficiently for an understanding of the present invention, said connections include cam levers, one set of which is seen at 6, cooperating with cam tracks in the upper and lower faces of the platen cam 1 on a main vertical shaft 8. This shaft is driven by a worm gear 9 meshing with a worm on the same short shaft ID with a large gear The latter in turn is driven by a gear |2 coaxial with a pulley 3 driven by a belt connection l4 from the motor l5, by which all the moving parts are operatedin the illustrated embodiment.

Considering now Figs. 2 and 6 to 10, improved means are herein provided for securing the test specimen on the platen 3. As seen in said figures, particularly Fig. 6, the platen is rectangular and is equipped with releasable clamping devices at each of its four sides. At each side the platen 3 has at its lower portion an inwardly extending slot IQ for the reception of a plate 20. On each plate there is a cross piece or holder strip 2| secured to it as by screws 22. The plates 20 and their holder strips 2| at two adjacent or non-opposite sides of the platen are held in fixed position as by pins or screws 23 extending upwardly from the base portion 4 of the platen. The other two plates 20 are not so pinned, but are afforded a limited in-and-out sliding movement relative to the platen for a purpose to be described.

Each of the four holder strips 2| is longitudinally slotted at its outer side face, as seen at 24 in Figs. 7 and 8. This slot is adapted to receive the corresponding inturned edge of the test specimen S in the manner seen in said Figs. 7 and 8. These edge portions of the specimen are adapted to be securely clamped in their respective holder strips 2| by clamps or clamping slides 25, one paralleling each holder strip 2| and guided for sliding movement on the corresponding plate 20. The clamps 25 are adapted to be forced into holding engagement with the specimen as by means of the clamping levers 26, one

for each side of the platen 3 and each pivoted as at 21 on the corresponding plate 20. Each clamping lever has at its inner end a clamp camming portion 28 and a flattened locking portion 29. By swinging the clamping levers 26 in the clockwise direction as seen in Fig. '6 their cam portions force the clamping slides inwardly into specimen-holding position as in Figs. 7 and 8.. In this position the specimen, generally a fabric of some sort, is firmly held along each edge portion, being tightly nipped between the upper wall of the slotted portion of the particular holder strip 2| and the upper corner portion of the corresponding clamp 25. The clamps preferably have their inner faces downwardly and outwardly inclined, as illustrated, to facilitate this clamping action. By moving the clamping levers through approximately their flattened portions 29 engage the clamps, this locking the latter and the levers in clamping position.

Means desirably is also provided for stretching or holding the specimen under tension, in two directions, while it is on the platen 3. To this end, the plates 20 and their attached holder strips 2|, at two non-opposite sides of the platen 3, those at the lower portion of Fig. 6, are permitted a limited in-and-out sliding movement as previously mentioned. At those sides the plates and holder strips are normally urged outwardly by one or more symmetrically disposed coil springs 30 received in recesses in the plate 3 and each bearing outwardly against a collar 3| on a stud 32. The inner end of each such stud extends centrally into and acts as a guide for the corresponding spring and its outer end is threaded into a hole tapped through the vertical wall of the adjacent holder strip 2|. The outer ends of the studs are formed as headless screws, being slotted or otherwise formed for engagement by a screwdriver or the like inserted through the slotted portion of the holder strip, on removal of the corresponding clamp 25. By thus turning the studs 32 the tension of the springs 30 may be adjusted as desired, to regulate the tension under which a test specimen is held.

Outward movement of these spring-loaded plates 20 is limited by their outward engagement with clamp-spreader levers 35 pivoted on studs 36 removably threaded into the base portion 4 of the platen, opposite the outer ends of said two movable plates 20. At their ends near their pivots these spreader levers 35 each have plateengaging cam portions 31 and a flattened holding portion 38. As shown in Fig. 6 the spreader levers 35 are in one released position, in which the springs are free to move the plates 20 and the holder strips 2| thereon outwardly, as also seen in Fig. 8. Thus a specimen previously clamped in the holder strip is then placed under tension.

To facilitate mounting and demounting a specimen, the spreader levers 35 are swung, in a counterclockwise direction as viewed in Fig. 6, to move the corresponding plate and holder strip inwardly to "a position as in Fig. 7, compressing the springs 30, and allowing the corresponding clamps 25 to be backed away from and thus free the specimen, when the corresponding clamping levers 26 have been shifted to their unclamping positions. The reverse procedure is followed for spreading or separating the holder strips and the corresponding clamps, in connection with installing a specimen on the platen. It will be noted that the clamp-spreader levers 35 each have two released positions, namely, either as seen in Fig. 6 or in a diametrically opposite position, while in their spring-compressing position they stand with their handles projecting outwardly, at right angles to said positions, as seen in Fig.

The clamping mechanism as illustrated in Figs. 6, 7 and 8 is adapted to accommodate the heavier, thicker test specimens, such as carpets, rugs and like heavy pile or other fabric, or any comparatively thick, flexible sheet material to be tested, as indicated by the reference character S in said figures. For mounting materials of an intermediate thickness or bulk, such for example as plush fabrics for automobile interior and seat coverings, canvas, duck and various other materials of corresponding bulk, as represented at S, in Fig. 9, auxiliary clamping means may be provided such for example as shown in said figure. As there seen, each of the clamps 25 has removably secured to its top face a plate 40 of a width to extend inwardly beyond the front edge of the clamp and substantially into engagement with the vertical rear wall'cf the slotted portion 24 of the corresponding holder strip 2|, in the holding position of the clamp 25, so as to engage and grasp the test specimen S between the plate and said wall. The specimen is also engaged and held between the upper face'of the plate 40 and the top wall of the slotted portion of the holder and if desired a second plate ll may be provided, or the plate 40 may be upwardly extended, to engage and grasp the fabric between such member I and the outer edge of the top wall of the slotted portion of the holder 2!, as illustrated in said Fig. 9. These auxiliary clampingelements are removably secured to the clamps 25 as by screws 42.

For flexible sheet materials of a still thinner character, such for example as garment fabrics and various others, as represented at S in Fig. 10, alternative clamping means may be provided in association with the platen 3, such for example as illustrated in said figure. As seen in each of Figs. 6 to 10, the specimen-receiving portion of the platen 3 is chamfered along its upper side edges, making the top portion of slightly reduced size. The vertical wall of this reduced portion, at each of the four sides of the platen, is formed with an inwardly extending slot 44 adapted to receive the horizontal flange of an L-shaped clamping strip 45. The down-turned edge portions of a relatively thin test specimen S, as seen in Fig. 10, are received between the vertical faces of the reduced portion of the platen and the vertical flanges of the clamping strips 45. The latter are removably held in clamping position as by the screws 46 tapped into the platen below the clamping strips 45 and having relatively large heads adapted to overlap the latter.

It will be seen that the specimen-holding platen or anvil is universally adapted for the holding reception of flexible test specimens of widely varying body of thickness, ranging for example from the heaviest of fabrics, such as long-pile Axminster carpets and other pile fabrics down to such relatively thin materials and fabrics as sheetings, shirtings and the like. The apparatus is also adapted for use in testing even thicker materials or stiffer or even non-flexible materials by securing them to the base portion 4 n place of the holding portion 3 of the platen or y fixing them to blocks similarly installed in place of said portion.

Returning to Figs. 1 and 2, there is provided above the main platform 2 an upper frame in- :luding a hollow pedestal 50 at one corner portion of the platform. Projecting inwardly from the pedestal is a frame piece 5| having upper and lower arms 52, 53. The upper arm 52 together with an extension 54 thereof forms an arch spanning the specimen platen, diagonally of the platform 2. At its end opposite the pedestal 58 this arch is supported by a post 55 rising from the lower framing in the cabinet I. As in the previous application, this upper frame serves to support the Wear-producing mechanism and other associated parts to be described.

The wearing action on the test specimen is performed by a shoe 60, in cooperation with the moving platen, in a generally similar manner as in said earlier application, through the oscillation of the shoe while in pressing contact on the moving specimen, with or without an action of intermittent impact of the shoe upon the specimen.

The apparatus as .herein illustrated embodiesimportant improvements in the construction and arrangement of the wearer shoe and its supporting and operating parts. As seen in' Figs. 2 and 11, the shoe 60, of circular form, has a neck 6i which is removably secured in a socket in the bottom of a shoe holder 10, as by one or more set screws II. A dowel 12, Fig. 2, in the holder socket and receivable in a corresponding recess 62 in the shoe, see also Fig. 17, positively locks the shoe against turning in its holder.

Said-shoe holder 10 is demountably held, as by set screws 13, at the lower end of the vertical tubular shoe-carrying shaft 15. This shaft, and consequently the shoe 60, is supported for rotary oscillation about its own axis and also for vertical reciprocation.

For this purpose the shaft 15, as best seen in Figs. 11 and 12, is slidably and rotatably received in a bushing 16 carried by the upper arm 52 of the top frame. This arm is hollow. providing within it a channel ll communicating with the interior of the pedestal 50, for carrying off the worn particles or dust from the specimen being tested, the shoe 60 being centrally apertured at 63, as is also its holder 10, for upward travel of the dust through the shaft 15 to said dust channel 11. The shaft bushing 16 extends above the lower wall of said hollow arm 52 and into said channel 11. At its upper end is a cap 18 centrally apertured to support an open tube 19 extending down into the shaft 15 but spaced from it. The cap 18 and said tube are held against upward movement during the operation of the machine as by a retaining screw 80.

In Fig. 11 the shaft 15 and shoe 60 appear in their raised position, in which the top of the shaft comes substantially level with the inner face of the bottom wall of the arm 52 but is spaced below the cap 18. The vertical movement of the shaft and shoe, downwardly from their position of Fig. 11, and which at the most need be but slightly greater than the thickness of the given test specimen, is such that the shaft is never withdrawn below the bushing 18. The upward extension of the latter, together with the cap I8 and the tube 19, provides a chamber 8| above the shaft in open communication at all times with the interior of the shaft through the cylindrical space between the latter and the outer wall of the tube 19.

Heretofore dimculty has been experienced by reason of accumulation and caking of the worn particles or dust at the upper end of the shoe shaft. Despite the tightest packing the finely divided worn material, generally an extremely fine powder, would collect around and above the top of the shaft and interfere with its movement.

This dimculty has herein been overcome by the provision of said clearance chamber BI and the additional provision of an air-entrance or cleaner passage 82, Fig. 12, drilled inwardly through the arm 52 and the bushing I6 so as to open into the chamber 8l, communicating between the latter and atmosphere. By reason of the partial vacuum or negative pressure in the shaft 15 and dust channel 19 as maintained by their communication with the collecting end of the dust system, to be referred to, an inflow of air is set up through said cleaner passage 82, into the chamber BI and thence downwardly about the tube 19 into the shaft 15. Thus any collection of dust at the upper end of the shaft is prevented and the latter is kept free of the objectionable accumulation mentioned.

As also seen in Figs. 11 and 12, means desirably is provided for taking samples of the wornoff particles or dust, in the course of or after a test, for use in studying the wearing action on the particular specimen. The arm 52 of the top frame, as in the preceding application, has an inspection and clean-out formation in its top wall, opening into the dust channel 11, above the shoe shaft 15, this opening being formed in a boss 83 on said arm 52. On this boss is an annular washer and closure-retaining ring 84 screwed or otherwise secured to it, as clearly seen in Fig. 12. The clean-out opening is closed by a removable cap 85 which conveniently may have a knurled knob 86 for manipulating it. The cap is firmly and removably held in seated position on said ring 84 as by a bottom-clamping member 81 secured to it as by a screw 88. Turning of the cap is adapted to engage the ends of said clamping member beneath circumferentially spaced inward projections 89 on the ring 84.

This closure cap 85 serves also as a support for the dust-sample collecting device above referred to. As seen in Figs. 11 and 12 said device comprises a small section 90 of wire screening or other perforate material the upper portion 9| of which is removably engaged beneath the head of the screw 88 on the cap. This sample-collecting screen is proportioned and arranged to extend downwardly into the path of the dust in the channel 11 of the arm 52. The screen is of less area than that of the dust channel, so as not to interfere with the action of the dust-collecting system. By merely removing the closure cap 85 worn particles or dust may be obtained for examination at any time. The screen 90 is readily removable, when its use is not desired, or it may be demounted and replaced by other similar specimen collectors, during the course of a test, if a number of dust samples are desired, the screens serving as convenient instruments for handling and studying them. In this connection screens having apertures of various difierent sizes may be employed, depending on the character of the test specimen.

Still referring particularly to Fig. 11, the shoe shaft 15 is guided, for rotation and vertical reciprocation, by a sleeve bearing 95, the upper end of which is fastened in a crosshead 96 having lateral trunnions 91 journalled in the shoe lifter arm 98, Fig. 1. This lifter arm is a double or forked element, the cross head 96 being received between its two parts. as clearly seen in Fig. 11. The shoe shaft I and said sleeve bearing 95 move up and down together, while the shaft is also given an oscillatory movement in said sleeve bearing and in the-crosshead 96, the latter having a bushing 99 receiving the shaft. An anti-friction bearing I00 is provided above the crosshead and the sleeve between said parts and a collar I0l fast on the shaft and through which the latter is oscillated.

The mechanism for so oscillating the shaft is similar to that of the previous application, including an arm I02, Fig. 11, projecting laterally from the collar IN on the shaft and connected through a link I03, Fig'. 1, to an arm (not shown) on a collar I04, the connection between said arm of the collar I04 and the link being such as to allow up and down movement of the latter with the shaft 15. Said collar I04 is fixed at the upper end of a hollow shaft I05, Fig. 3, extending vertically through the hollow pedestal 50, similarly as in the previous application. Said hollow shaft I05 is oscillated by a pitman I05, Fig. 3, pivoted at one end, at the left in said figure, to a collar I05 fast at the lower end of said shaft and pivotally connected at its other end to a crank disk coaxial with the gear I2 and pulley I3 previously referred to.

The sleeve bearing 95 and the entire shoe operating assembly are further guided by the lower arm 53 of the top frame, through which said sleeve and the shaft 15 extend.

Referring again to Fig. 11, the shoe sleeve bearing 95 terminates at its lower end in an annular flanged foot I01 seating on another anti-friction bearing I09 supported on the shoe holder 10. A laterally projecting annular cup I09 may be provided below the bearing I08, held between it and the shoe holder, for catching any oil that might escape at the bearing or other point above it, and which might otherwise reach the shoe and the test specimen. Such protection is important because even a very small quantity of oil on the wearing face of the shoe or on the specimen is likely to introduce a factor of irregularity in the test.

As an additional safeguard in this connection we may provide a further drip plate or oil and dirt catcher, preferably below the cup I09 and adapted to receive possible overflow from the lat ter and to catch any other dirt or foreign matter which might otherwise fall onto the specimen being tested. As illustrated in Figs. 2, 5 and 11, this additional means comprises a two-piece glass or other plate IIO, see particularly Fig. 5, straddling the shoe holder and apertured for passage of the latter. Each section of this plate is supported by a bolt III depending from a bracket I I2 secured to the stationary lower arm 53 of the top frame, see Fig. 11, spacer sleeves II3 on the bolts serving to hold the plate sections firmly in their horizontal position. The two sections are adapted to be swung apart, about their supporting bolts III, to give full access to the shoe and associated parts. They are held together in edgewise abutting relation, as seen in Fig. 5, as by means of hook II4 on one section and engageable with a button II5 on the other. The plate.

sections are also recessed at their juncture line, as at I I6, for. passage of the wear-measuring feeler device to be described.

From the foregoing it will be seen that the shoe 60, its holder 10, the shoe shaft 15 and the bearing sleeve 95 and parts connected to the latter are adapted to be moved up and down by the action of the shoe lifter arm 98 to which they are connected through the crosshead 96. The shoe shaft I5, shoe holder I0 and the shoe 60 are also capable of rotary movement about the vertical axis of the shoe and shaft, but only these main parts of the shoe operating assembly parit is down in pressing engagement on the test specimen,

The lifter arm 30 already referred to, for effooting the up and down movements of the shoe, is hung on the top frame member 5I, being pivotally connected at one end, at the left in Fig. 1, as at I20, to vertical links I2I, one at each side of the frame and pivoted thereon as at I22. At its other end said shoe lifter arm is pivotally connected as at I23 at the upper end of a lift rod I24 extending downwardly into the cabinet I and operated through mechanism therein which may be generally similar to that of the earlier application. Said mechanism is illustrated in Fig. 3 sufliciently for the purposes of the present application. Upward movement is imparted to said lift rod I24 by a horizontal cam lever I25 having its outer end pivotally connected to the lift rod, as at I26, and carrying at an intermediate point a roll I 21 cooperating with an adjustable eccentric or cam I2l=-on the shaft I0 previously referred to in connection with the drive for the platen. Said cam lever I25 is pivotally supported at its inner end as at I26 on a fixed cross piece I29 or other stationary part.

Downward thrusting action of the shoe and a continued pressing engagement thereof on the test specimen is efiected by the dropping of the cam lever I25, the lift rod I24 and the lifter arm 98 when the roll I21 rides off from its cam I2I The force of this downward impacting and pressing action is determined by an adjustable weight I30 at the lower end of the lift rod I24, see Fig. 3.

and that of the shoe, to avoid'damage to the platen or anvil 3 or to the shoe 60 by direct contact of said parts should a specimen be worn completely through.

Means desirably is provided for accurately controlling and adjusting the extent of vertical movement given to the shoe. For this purpose, referring now to the lower right portion of Fig. 2, the lift rod I24 has a threaded portion, above the platform 2, receiving a stop collar I32 engageable with the platform to limit down movement of said rod. Also on said threaded portion of the lift rod is a setting nut I33 the upper end of which'is tapered and marked with a circumferential scale I34 for cooperation with a longitudinal scale I35 on the rod I24, as on a marker sleeve I36 thereon. The scales may be calibrated in small units of vertical adjustment in the up and down movement of the wearer shoe, whereby a micrometer setting for the latter is had. The scales I34, I35 may be arranged so that by setting their zero indications opposite each other either the upper or the lower limit of adjustment for the bottom position of the shoe is obtained. The two threaded members I32 and I33 cooperate and are manipulable in the manner of a nut and lock nut, each being moved in turn until the scale setting is as desired and the two parts are in abutting, mutually locking position,

A stop I3I may be provided below the weight I30 to limit its downward movement pump and its bearings.

As previously explained, and as in the earlier application. the worn particles of lint or dust are carried off from the test specimen as produced, passing up through the shoe 00 and its shaft I5 to the channel 11 in the upper arm 52 and which continues through the base or supporting frame element 5I into the pedestal". Referring now to Fig. 3, the dust is taken from the pedestal 50 through an outlet I40 at its lower portion, within the cabinet I, and through a conduit I4I communicating between said outlet and a vacuum tank I42 mounted in the cabinet. In the tank is a dust receptacle or bag I43 detachably hung on a removable cover plate I44 for the tank, the cover plate having an inlet I45 for the dust and at which the lower end of the conduit I is connected. The bag I43 is of paper, fabric or other material of sufllciently porous character to allow air to pass through it but while retaining the dust particles, similarly as in known vacuum cleaners.

The negative pressure or partial vacuum in the dust-collecting system is maintained by a pump I46, Fig. 3, driven through a belt or other connection I" with the motor. The intake side of the pump is connected through piping I48 with the outlet I43 of the vacuum tank, while the outlet or pressure side of the pump discharges through a pipe I50 opening to atmosphere at I5I. A considerable vacuum or negative' pressure is found desirable, generally somewhere between 15 and 30 inches (column of water), depending somewhat on the character of the test material, and the pump employed is of corresponding capacity, that illustrated being of a rotary type operating with oil. Since a given test may be continuous over a period of several days, during which the pump operates continuously, it is important that its bearings receive constant lubrication, particularly if they are not of a ball-bearing or other anti-friction type. Accordingly, as seen in Fig, 3, an air reservoir or cup I52 may be provided, adapted to supply both the operating mechanism of the Oil is distributed from the cup I52 through a feed line I53 having branches, one of which is indicated at I54, lead-- ing to the bearings at the opposite ends of the pump shaft, and a branch I55 leading to the interior of the pump, through the intake-piping I48. Oil from the cup I52 is forced up through a tube I56 and discharged above the upper end of the feed line. Air pressure is availed of for so upwardly forcing the oil, air being taken from the pipe I50 at the pressure side of the pump through a connection I51 extending into the cup I52 and communicating with an air pressure tube I58 having a reduced portion which opens upwardly. into the lower end of the oil tube I56, whereby the air pressure forces the oil upwardly through said tube I56 from the supply in the cup I52.

In view of the importance of maintaining a substantially uniform negative pressure in the dust-collecting system, as appropriate for the particular test material, means desirably is provided for readily determining the pressure at any time and also for relieving it if necessary. Accordingly, there is herein illustrated a vacuum or negative pressure gauge 160, Figs. 1 and 13, graduated to read in inches of water. The gauge is adapted to be placed in communication with the channel 11 in the upper arm 52 through a coupling I6I threaded into an appropriate aperture in a wall of said arm, see particularly Fig.

13. It will be understood that the suction or negative pressure pulsates with the movement of the shoe, between a maximum at the times when the shoe is firmly engaged on the specimen and so restricting the entrance of air through the shoe, and a minimum when the shoe is lifted and the passage through it is accordingly wholly open. Hence if the gauge were always in communication with the air channel its indicator would pulsate correspondingly. To avoid this the gauge is so arranged that normally it is shut off, but may readily be caused to operate whenever a reading is desired.

Referring to Fig. 13, a control valve is accordingly provided for the gauge, including a valve housing I62 threaded into a laterally extending chamber I63 in the coupling I6I. The latter has offset longitudinal passages I64 and I65, the lower passage I64 communicating between said chamber and the air channel 11 of the arm 52, and the upper passage I65 leading from said chamber to an upper chamber I66 into which the gauge stem I61 opens. At the inner end of the housing I62 is a seat I68 for a valve I69 on a stem I slidable in the housing and extending out through suitable packing Hi to an operating button I1-2. A spring I18 between the packing and said button normally urges the valve outwardly into closed position on its seat. In Fig. 13 the valve is shown open, as if the button were being held in by the observers finger. In this position the gauge is in communication with the suction system, through its stem I61, the upper chamber I66 and passage I65, and through an annular passage I13 opening into the valve housing behind the valve, thence through the valve opening and the lower passage I64 into the air channel 11. Normally during operation of the apparatus thevalve accordingly stands closed and the gauge indicator remains at rest, at the zero end of its scale. .To obtain a'reading, however, it is necessary merely to press in the valve button I12, the valve again automatically closing when the reading has been made and the button released.

To relieve the negative pressure in the system or to prevent its passing a desired maximum, a venting or bleeder valve I15 may be provided at a convenient point, for example, adjacent the gauge I60, as seen in Fig. 1. Referring to Fig. 14, this valve comprises a plug or stem I16 threaded through a boss I 11 on the wall of the upper arm 52 of the top frame. The inner portion of the plug has .a beveled or inwardly deepening slotted formation I18 so that by turn ing the valve in or out the vent provided by said formation may be closed completely or opened to various sizes. A coil spring I19 sur-- rounding the valve stem, between the boss I11 and the head or adjusting button at the outer end of the valve, urges it outwardly, taking up any play between the threaded member and the supporting wall of the arm 52 and so tending to hold the valve in any given position and against unintentional shifting.

In testing materials as herein contemplated it is generally important that the wearing action on different specimens which are to be compared shall be as nearly absolutely uniform as possible. The character and construction of the wearing surface for the shoe 60 therefore is a prime consideration, and much experimental work has been done in determining the most effective arrangements for the purpose. With said uniformity of action in view we employ in most instances a wearing surface the main area of which is flat, hard and extremely smooth, avoiding surface irregularities which might produce a different abrading action at different times. In this connection our testing system also contemplates that there shall be one master or standard machine which may be used as a norm for establishing standards a to thewearing qualities of the various materials. Such machine is kept at some test headquarters, carefully guarded against being tampered with, and in a special room or other location where it may be operated under controlled standard conditions as to atmospheric temperature, relative humidity, cleanness and others. Comparable results with other similar machines necessitate that the wearing instrumentalities be as nearly as possible identical. and such identity is best obtained in the use of a fiat, smooth, hard wearing surface, as above mentioned. Ordinary abrasive surface means, such for example as generally used in grinder wheels, even wherein the surface is composed of minute granules or crystals, lack the desired uniformity of action, due largely to the surface irregularities, even though small, and to the wearing off of particle of the surface material which work into the test specimen and introduce uncertainty and nonuniformity of action.

Referring in this connection to Figs. 2, 11, and 17 to 24 inclusive, the wearer or shoe unit 60 comprises a wearing surface member or means 64 which as shown is made detachable from the foot and is cemented or otherwise secured in a shallow socket therein. As stated, this wearing surface element is extremely hard and smooth, having a mirror finish. One of the best materials we have found for the purpose is that known commercially as Norbide, having a hardness approaching that of diamond. Another material successfully employed is glass, polished to a mirror finish. With some test specimens we have satisfactorily used a very hard steel, such for example as Colonial .795 quenched'in oil from 1900 F. soaked till cold and-drawn to 400.

When steel is used the shoe body 60 and the surface means 64 may be integrally formed or otherwise, while with Norbide, or with glass or in any instance the detachable construction may be preferable, for reasons of economy and of replacement.

W'hile the main area of the wearing surface of the shoe is flat and highly polished one or more channels or grooves desirably are formed in it, the number and arrangement of which may be widely varied, for use with different test materials. Obviously some materials wear faster than others, so that a shoe suitable as the standard instrument for one class or type of material may wear a different character of material at too rapid or too slow a rate for testing purposes. With the same test material the rate of wear, other factors such as the force and rapidity of impact and the rate of oscillation remaining the -same, depends mainly on the wearing surface channeling. In general, the rate of wear increases with an increased number of lineal interruptions of the surface, with the increased number of subdivisions of the surface, the smaller such subdivisions, the greater the wearing rate. The directional arrangement of the lines and the accompanying configuration of the subdivisions also is an important factor. Another factor is the relation of the channeling to the central aperture 63 and to the periphery of the shoe, and we herein illustrate various shoe surface formations in which the channels provide air passages from the edge to the center, from edge to .edge,

between two intermediate points without com-- municating either with the edge or the center, or between an intermediate point and either the edge or the center, all having a somewhat differing action, due partly to the nature of the contact with the specimen and partly to the aircooling and the dust-conveying effect of the channels in cooperation with the central aperture communicating with the vacuum system.

One construction and arrangement of the surface channelling is shown in Fig. 17, being the same as in Figs. 2 and 11; In this instance the channels 55 are radial and extend from edge to center, each providing an air passage communicating from the side face of the shoe to the' central aperture 63, eight such radial channels 65 being illustrated in this instance, equally spaced. Thus when the shoe is down in pressing contact on the specimen air may enter the system through the channels, maintaining a dust-collecting flow and cooling the shoe. A greater or less number of the symmetrically disposed radial channels may be provided. This shoe, having its wearing surface of the materials as previously referred to, is particularly adapted for use in wear testing Axminster rugs and carpets, and other fairly heavy pile fabrics, as well as various other materials.

Fig. 18 shows the wearing face of a shoe in which the channels 66 are spirally disposed and extend from the edge to the central aperture 83, each through one convolution. Three such spiral grooves or channels are illustrated, starting at equally spaced points at the shoe edge and ending likewise at equi-spaced points about the central aperture, the two ends of each channel 86 being substantially opposite each other radially. In this form the cooling and dust-collecting effect is particularly eflicient, adapting it for dense materials and others with which there is considerable heat generated in the wearing action.

In the shoe form of Fig. 19, the channels 61 are rectilinear and in a lattice arrangement, including two perpendicular diameters with parallel chords equally spaced at each side thereof. This construction includes edge to center communication as well as edge to edge passages. As in the other examples, increase in the number of channels and subdivisions of the wearing surface increases the rate of wear. For some of the durable materials such as linoleum, and fibre, cellulosic and other compositions, the squares or subdivisions of this lattice form, or the various subdivisions of the other forms, may be relatively small even approaching in width that of the channels themselves,

In Figs. 20 and 21 two further forms are illustrated, wherein the channels 68 and 6!! respectively are closed, along continuous paths, having neither center nor edge communication. In Fig. 20 the channels are chordal, ending short of the periphery, and. forming a rectangle, while in Fig. 21 they are concentric. Additional channels may be provided in the form of Fig. 20, while in Fig. 21 the number of channels, of which three are shown, may be made greater or less.

In said Figs. 20 and 21, wherein the channels'do not lead to the central aperture 63, additional provision for air-cooling may be made as by means of one or more passages 68 and 89 respectively formed in the shoe above the wearing face and leading into the center aperture from the side face of the shoe. These serve to maintain an air flow through the body of the shoe adjacent or in the wearing surface element, carrying ofl' heat through the vacuum system. Bimilar channels may be provided in any other of the shoe forms if desired, as indicated at in Fig, 11.

Desirably means is provided for automatically stopping the machine in casethe wearer shoe reaches a predetermined heated condition at which it is preferred to interrupt the test. Such condition isof infrequent occurrence sometimes arising in the testing of extremely durable materials, and the means referred to may be of a readily demountable or may be rendered inoperative when its-use is not desired, or it may be employed as a precautioning measure at any time.

For this purpose, referring to Figs. 22 and 23, the shoe 68, or as there shown the shoe holder I8 included in the unit is equipped with a thermally responsive device III illustrated as a bi-metallic element partly encircling the holder adjacent the shoe and attached as by a screw which serves also to ground said element onto the machine. At the determined critical temperature the straightening of the thermal element 10 brings it into electrical contact with a point 18 on a contact arm 18 attached to a convenient stationary part, such as the lower arm 53 of the arch or top frame, and insulated from it. Through appropriate wiring connection, as will be referred to in connection with the wiring diagram, closing of a circuit at the thermal element acts to open the motor circuit and stop the apparatus.

In the testing of some materials, in which higher temperature conditions at the wearer head or shoe are to be expected, in the absence of some provision to the contrary, additional cooling for the shoe may be supplied. In Fig. 24 one form of such cooling means is illustrated, in which the shoe holder 18A is cored as at 14 to provide a circulating chamber for water or other fluid, an inlet and an outlet for which is indicated at I4 and W respectively. A rubber or other flexible hose 14 connects the inlet 14' with a water or fluid supply, while a similar connection l4 leads from the outlet 14 to waste or to a cooling and recirculating system. The hose connections are such and are so supported, as on the top frame, as not to interfere with the motions of the shoe,

Improved means coordinated with the wearing mechanism is provided for periodically measuring the depth of wear and charting a record of the same. Referring to Figs. 1 to 3, 25 and 29 to 31 a recorder drum I88 isdemountably fixed as by a thumb nut I 8I at the upper end of a vertical, rotary drum-operating or recorder shaft I82. This shaft is supported and journalled in upper and lower bearings I83, I 83 and extends vertically through the shoe-oscillating shaft I85 in the pedestal 58. It is driven in accurately timed relation with the wearing mechanism, including both the specimen platen and the wearer shoe, by a worm wheel I84 at its lower end and meshing with a worm I85 fast on a horizontal shaft 215 to be more fully described; see particularly Figs. 29 to 31. It is suflicient here to note that said shaft 215 is driven at selective speeds through a clutch-controlled change-speed gearing, to be referred to later and which receives its drive from a worm gear I 86 turning on a bearing bushing I 86 in a bearing I86 on a bracket I33 depending from the cross member I23. Said worm gear I" is driven by a worm I31 fast on a lower horizontal shaft I33 rotatable in another bearing I33 on said bracket I33. The inner end portion of said lower horizontal shaft I" receives further bearing support in a vertical bracket J33 on the stationary framing and has at its end a bevel pinion I90 meshing with a like pinion I9I at the lower end of themain vertical shaft 8 for the platen cams.

As seen in Fig. 1 and in detail on a larger scale in Fig. 25 the recorder drum I" is adapted to receive a paper or other chart or sheet I92 on which the record is to be made. A typical form of chart is illustrated in the earlier application and need not be duplicated in detail here. has a chart-backing surface or element I93 of a smooth, firm material but which is adapted easily to be entered by the sharp point of the marking instrument in case it pierces the paper or other material of the chart. As shown in Fig. 25 said element I93 is in the form of a cork sleeve drawn onto the drum and having a tight fit on it. The chart I92 of paper or other flexible sheet material is readily installed on and removed from the drum. In the illustrated example its lower edge is set inside one or more arcuate positioning clips I94 at the base of the drum, the overlapped end portions of the chart being brought behind one of such clips I94. At its upper edge the chart is held by a releasable clamping means such as the spring fingers I95 on brackets I96 projecting from the top of the drum I80.

Improved marking means is herein disclosed for making the record on the chart. As seen in Figs. 1, 2 and 25 the marking device or needle is removably carried at the upper end of a vertically movable marking arm 200, the vertical movements of which are controlled by the feeler and timing control mechanism to be described. The marking device comprises a cup or reservoir 20I for a supply of ink and having depending forked portion 202 adapted to straddle a button 203 near the upper end of the marker am 200. The upper extremity of the latter is vertically slotted as at 200' to receive a grooved portion of a nipple 204 projecting from the base of the reservoir and having an ink passage 205 communicating with the main ink chamber of the reservoir. A needle holder 206 having a needle 201 extending axially through it is received on the nipple 204, as by a Luer slip connectionwith it. The needle itself has a longitudinal bore or passage 201' communicating at its rear end with the channel 205 leading from the ink reservoir 2M. The passage in the needle is of small or substantially capillary diameter, such as to supply and maintain a small quantity of the ink at the outer end of the needle, in readiness for marking, but; avoiding any drip. The outer end of the needle preferably is sharp pointed a illustrated in Fig. 25, for indenting or piercing the chart, this action being facilitated by the readily penetrable character ofthe underlying cork or like element I 93.

It will be understood that as in the previous application the marker arm 200 and the described marking device on it normally stand at a level at the upper portion of the drum, at or near the top of the recording space on the chart, and that said parts are periodically allowed to urlng feeler to be described, so as to produce a mark at a corresponding level on the chart.

When so moved down into marking position, the

The outer cylindrical face of the drum drop, to an extent determined by the wear-measmarker device i positively moved inwardly, radially of the drum, to contact and mark the chart, and is subsequently positively retracted.

For this purpose, as seen in said Figs. 1, 2 and 2 5, the marker-carrying arm 200 has at its upper portion a laterally projecting vertically slotted guide finger 203 which is slidable up and down, with the movement of the marker arm 200, along the adjacent edge of a vertical fin 2| I). The latter projects radially at the upper end of the marker-turning rod M I which is held against vertical movement and is supported for rocking on its axis, as by means of upper and lower guide bearings 2I2, 2I3 on adjacent portions of the upper-framing. A'torsion spring 2 surrounding the rod 2 has one end adjustably secured to it as by a collar 2I5 and its other end anchored in a stationary part, such as the upper bearing 2| 2. This spring 2| 4 acts normally to urge the vertical rod 2 in a direction to move and hold the fin 2H) and the marking needle 201 away from the chart, the tension under which the parts are so held being adjustable by means of the collar 2I5 referred to.

The vertical movements of the marker arm 200, and the positive inward swinging and outward retraction of the marker device by the rod 2 are effected by a linkage system of a character similar in general to that of the previous application but herein embodying various features of improvement. Referring to Figs. 1 and 2, and also to Figs. 26 to 28, the marker arm 200 is supported by upper and lower indicator or feeler arms 220 and 22I having their outer ends pivotally connected to said marker arm 200 as at 222 and 223 respectively. Intermediate its ends the upper arm 220 has a fixed point of pivotal support, as at 224, on a strap 224 depending from the arch member 52; see Fig. 1. The lower arm 22I likewise has a fixed pivot, as at 225, on the arch or top frame. The marker needle 20! at the upper end of the marker arm 200 is thus supported for vertical movement in a straight line and in true parallelism with the vertical feeling movement of the wear indicator, detector or feeler 240 hung on the upper arm 220 in a manner to be described.

The lower arm HI and consequently the marker device and associated parts including the wear feeler are normally held up substantially in the position as illustrated in Fig. 1 by a removable stop 226 on said lower arm 22I projecting across the upper edge of a. further supporting arm 221. The latter is pivoted at one end on the same fixed pivot 225 with said lower arm 22I and has its other end pivoted as at 228 at the upper end of a link 22!. Vertical movement of this link 229 serves to let down and to elevate the marker, through the medium of a lower link 230, Figs. 3, 30 and 31, having a fixed pivot at its lower end, as at 23I. At an intermediate point along said lower link 230 there is pivoted as at 232 a lift rod 233 connected by a pivot at its lower end to a can: lever 234. The latter has a fixed pivot at one end, as at 234, Fig. 30, and at an intermediate point carries a cam roll 235 adapted to ride on a cam disc 236. The free end of said cam lever may be weighted, as at 234*.

The cam disc 236 is fixedon the shaft I38 previously referred to in connection with the drive for the recorder drum. It has a relatively short and steep-walled notch 231, Fig. 30 which, on coming opposite the cam roll 235,will allow the latter and the described linkage connections to drop sharply and cause them to be lifted again after a brief interval. This conditioning of the linkage system for down'movement occurs once for each rotation ofthe disc 236, which has an accurately predetermined and generally relatively short period of revolution per minute. Said linkage motion actually takes place, however, only when permitted by other control mechanism to be described in connection with Figs. 29 to 32.

Considering again the marker turning rod 2 as best seen in Figs. 1 and 2, improved means is provided for positively rocking said rod to move the marker needle 201 into contact with the chart and to retract it. These movements are respectively opposed and aided by the torsion spring 2 already described. The actuating force for the movements is derived irom the lowering and lifting action of the marker arm 200 and its associated link connections, and herein directly from the lower supporting arm 221 and its connected link 229. Said arm 221 has a laterally projecting pin 221* which in the course of the down movement of the arm is adapted to enter a slotted formation 221 at the end of one arm of a bell-crank 221 on a fixed pivot 221 on the lower arm 53 of the top frame. The other arm of said bell-crank is pivotally connected by an adjustable link 221 to lateral finger 2! l on the lower portion of the rod 2| I. Thus during the descent of the arm 221 its pin 221 engages and rocks the bell-crank in a counter-clockwise'direction as viewed in Fig. 1. This in turn rocks the rod 2 in a positive, firm manner, in the direction to swing the vertical fin 210 in toward the chart and to cause the needle 201 to make a mark on it. By reason of the interengagement of the pin 22! in the slot 221 of the bell-crank a reverse turning of the latter is afiected during the subsequent raising of the link 229 and am 221. The rod 2 accordingly is reversely rocked to swing the fin 2H) away from the chart, positively retracting the needle, supplementary to the influence of the spring 2 l4.

The described linkage and cam mechanism associated with the marker arm 200, together with said further controls of Figs. 29 to 32 determines the times at which the periodic measurements and recordings shall be made, 'by allowing the marker mechanism and the wear detector or feeler 240 to move down at the selected intervals. The extent of this down movement is in direct ratio to the depth of wear which has been effected on .the specimen at the given time, as detected or measured by the feeler element 240 which engages or feels directly on the worn surface of the specimen. Said feeler as herein disclosed is of improved construction, whereby pos-- sible irregularity in its positioning is substantially reduced, the feeler being enabled in effect to float on the specimen and to give an indication of the average height or depth of the worn area of the specimen'contacted by it. Novel provisions are also herein made whereby the ratio of the markings on the chart to that of the actual distance of wear may be varied, so that the vertical extent of the curve plotted on the chart may be made greater or less, to suit different conditions. For example, with a relatively thick specimen to be tested, such as a heavy Axminster carpet the total wearing-depth and accordingly the increments to be measured are relatively large, so that a charting ratio of perhaps tento one or even less may be adequate to plot a curve on which the successive points are adequately spaced vertically for convenient reading. with other materials, with which either the incremental or the total wear is smaller, larger charting ratios may be desirable, such, for example, as twenty to one, fifty to one or even greater.

Referring in this connection to Figs. 1, 2 and 26 to 28 inclusive, the feeler or detecting device proper comprises a flat disc, plate or caliper button 240, preferably having an inwardly and downwardly bevelled edge portion, to facilitate its seating on the specimen. In the illustrated example this feeler button has an area of approximately 1% square inches. At its upper face is a central stem 2 terminating in a ball 242. The ball 242 is movably received in the lower end of a socket member 243 which is spun over at its bottom edge as illustrated, sufliciently to retain the ball 242 while affording to the feeler button 240 a universal or floating movement relative to the socket member, and enabling it to tilt in any diametral plane.

The socket member 243 is adjustably threaded at the lower end of the feeler rod 244 the upper end of which in turn is adjustably threaded into a top-piece or cap 245 through which the feeler is connected to the upper arm 220 of the parallel linkage system, in any one of a number of different positions relative to it. It will be seen that the universal connectionbetween the feeler head or. button 240 and its supporting rod, and which permits the feeler head to float or tilt relatively to the rod, aiiords a greater degree of accuracy in measuring the average depth of the portion of a test specimen onto which the feeler is let down. For example, if some small area of the specimen, less than that of the feeler head,

stands at a higher level, such as a small hump or projection of any kind, the portion of the feeler head diametrically opposite such elevation will tilt down to the lower level and allow the feeler rod to come down to a level intermediate the lower one and that of the elevation. Thus in effect the feeler indicates the average level of the contacted worn surface. The feeler rod 244 as shown has a knurled head 244* fast on it to facilitate turning the rod for length-adjusting purposes, and whereby the feeler may quickly be set for cooperation with any given specimen. A knurled lock nut 244 desirably is threaded on the rod adjacent the cap piece 245 for locking said parts in .the desired relative position of adjustment.

The feeler-rod supporting cap 245 has a lower forked portion 246 through which. the upper tions is a laterally projecting arm 248. Each of the three portions of the feeler-rod cap 245 referred to has an aperture for the reception of a removable pin 249 for use in-connecting said cap 245 to the upper arm 220 in three different positions of adjustment, as shown for example in Figs. 26, 21 and 28 and which positions will hereinafter be referred to as positionsA, B and C as indicated on said figures.

In position A, that of Fig. 26, the removable pin 249 is set in an aperture 250 in the lower slotted portion 246 of the cap 245 and through a corresponding aperture 25! in the arm 220 (these apertures may be seen unob scured by the removable button, in Figs. 27 and 28). In this A position, of Fig. 26, the cap member 245 of the feeler rod is directly connected to the arm 220 and in such manner that the ratio between the feeler movement, in traversing the total worn depth to be measured, and the corresponding movement of the marker device 201 is relatively small, that is, nearest to a direct or 1 to 1 ratio. In the example illustrated this A position of the parts afiords a 10 to 1 ratio between the distance measured oif and marked on the chart and the actual corresponding worn depth indicated.

In each of Figs. 26 to 28 inclusive the feeler 240 is shown in the same lowermost position, in which it is assumed to be down in contact or substantially in contact with the bare platen. This bottom level is indicated by the dot-and-dash.

line bb, at the bottom of each of said figures.

the level at which the feeler makes its uppermost marking indication is shown in the several figures by the dot-and-dash line a-a, spaced above the bottom level lines b--b. The corresponding positions of the arm 220 are indicated at the upper portions of said figures by the dot-and-longerdash lines a-a, bb.

From a comparison of said Figs. 26, 27 and 28 it will be noted that the initial or a-a position of the arm 220 and the final or 13-21 position of said arm is the same in each of the adjusted positions of the parts, but the feeler 24!! starts its indications at succeeding lower levels. That is, while the total angular movement of the arm 220 is always the same, the vertical movement of the feeler 240 difiers. In Fig. 26 the relatively large vertical movement of the Ieeler between the wear lines H and b-b at the bottom of the figure corresponds to a marking movement of the arm 220 through the angle between the lines H and bb at the upper portion of the figure. In Fig. 2'7 the lesser feeler movement, between the wear lines a-a and b-b of that figure again corresponds to the same total marking movement of the arm 220 between the lines H and 11-17 adjacent it, while in Fig. 28 a still smaller ieeler movement corresponds to this same total movement of the arm 220.

Or to put it conversely, and going from Fig.

.28 to Fig. 27 to Fig. 26 the same incremental resulting markings may if desired be sumtantially as widely spaced vertically with said C-setting The initial level of the test specimen, that is,

as with the small ratio or more nearly direct A- have a preliminary down movement before contacting the surface of the specimen. The extent of this preliminary movement varies with specimens of difierent thickness and with the corresponding different adjusted positions A, B and C of Figs. 26 to 28. This is compensated for by adjusting the length of the rod 244 below the top-piece or cap 245 as permitted by the threaded adjustable connection between said parts. In

comparing these three figu es :it will be noted. that the feeler-rod length below the cap 245 is greater in Fig. 27 than in Fig. 26 and still greater in Fig. 28.

The mechanism by which the different adjusted positions B and C of Figs. 27 and 28 respectively are obtained comprises two links 252 and 253 having their adjacent ends pivotally connected as at 254. The vertical and longer link 252 is pivoted at its lower end to the arm 22!! at 255 while the shorter and more nearly horizontal link 253 is pivotally hung on the upper frame member 52 as at 255.

The lateral finger 248 of the cap 245 has a pinreceiving aperture 25! adapted to cooperate with a similar aperture 258 in the vertical link 252. Similarly the upperslotted portion 241 of said cap piece has a pin-receiving aperture 259 for cooperation with an aperture 250 in the upper link 253.

For the setting B, of Fig. 27, the pin 249 is removed from its position as shown in Fig. 26 and is inserted in the apertures 25], 258 of the lateral finger 248 and the link 252, the parts being manipulated to bring said apertures into alignment. In this B position the connection between the feeler rod 244 accordingly is through the lower portion of the cap member 245, through the lateral finger 248 thereon and thence through the lower portion of the link 252 onto the arm 220 at the pivot P int 255.

For the C position, of Fig, 28, the parts are manipulated to bring the aperture 259 at the upper end of the cap 245 into alignment with the aperture 269 of the horizontal link 253 and the pin 249 is then inserted in said aligned apertures. As seen in Fig. 28 the connection from the feeler rod 244 is then up through substantially the full length of the cap 245, through the outer end portion of the link 253 and downwardly through the full length of the vertical link 252 onto the arm 229 at the pivot point 255.

Releasable means desirably is provided for holding the pin 249 in its several different adjusted Positions. In the illustrated example this is efiected by an annular slot 249 in the neck of the pin 249 and adapted to have locking en'- gagement with wire- like spring fingers 249 and 249 fixed on the cap member 245. Said spring element 249 is vertically extended to have looking cooperation with the pin 249 when the latter is either in the lower aperture 250 orin the upper aperture 259, as seen in Figs. 26 and 28, while specimen such, for example, as .010 inch, .005'

' given test specimen, it being further noted that,

as in the preceding application, the feeler normally is elevated, substantially as in Figs. 1 and 2, above and out of contact with the specimen and in making each periodic measurement it may the intermediately located finger 249 is positioned to snap into said locking slot 249' of the pin when the latter is in the intermediate aperture 251 of the laterally projecting finger 248, as seen in Fig. 2'7.

It is desirable that the Ieeler button 249 shall age the test specimen with a predetermined and adjustable pressure, and also that the same predetermined pressure be maintained when using the different calibrations or marking ratios corresponding to the positions A. B and C referred to. Accordingly, as seen in Fig. 1, the upper arm 22. is accurately balanced or loaded

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