US2683935A - Shoe sole grading machine - Google Patents

Description

July 20, 1954 C. C. THOMAS ET AL SHOE SOLE GRADING MACHINE Original Filed Sept. 10, 1948 9 Sheets-Sheet 1 cuAQLzsCfmomwa 1 HEREERTV CARNESJDECEASED e7 HORAM.CARNE5,EXECUTR\X y 1954 c. c. THOMAS ET AL 2,683,935

SHOE SOLE GRADING MACHINE Original Filed Sept. 10, 1948 9 Sheets-Sheet 2 \Nvzm-rorzs C HARLES C. Hc MA= HERBEQT \M cAmdzspzcaAseo July 20, 1954 c. c. THOMAS ET AL SHOE SOLE GRADING MACHINE s w 55 w i s E m o mo e T 5 h N\E s c 9 Wm N%c \LW R Q HE 6 R E H Original Filed Sept. 10, 1948 a7 FLORA M. CARNESIEXECUTQD y 0, 1954 c. c. THOMAS ET AL 2,683,935

SHOE SOLE GRADING MACHINE Original Filed Sept. 10, 1948 9 Sheets-Sheet 4 13 Z M Q \NVENTORS CHARLES C. THOMAS HER6ERT \AZCAQNE. DECEASED July 20, 1954 c. c. THOMAS ET AL 2,683,935

SHOE SOLE GRADING MACHINE INVENTORS C HARLES C. TuoMAs HERBERTWCAQNES, Dace/x550 By FLORA M CAQHESIEX ecumm July 20, 1954 c. c. THOMAS ET AL SHOE sou: GRADING MACHINE 9 Sheets-Sheet 6 Original Filed Sept. 10, 1948 HERBERT \M CARNES. oEcEAsE'p July 20, 1954 c. c. THOMAS ET AL SHOE SOLE GRADING MACHINE 9 Sheets-Sheet 7 Original Filed Sept. 10, 1948 mm m A a N mm ms 0 E m o m fi 4% W 8 1 WM 5 TA m m i m m H I .3 a5 C E L Y 1 Q I Q m3 #3 R\ w Q m Q l|| HI l m6 1 R \3 m3 hm a July 20, 1954 c. c. THOMAS ETAL SHOE SOLE GRADING MACHINE 9 Sheets-Sheet 8 Original Filed Sept. 10, 1948 x F J B FLORAM. CAQMES. ExEcu-mm Qmi July 20, 1954 c. c. THOMAS ET AL SHOE SOLE GRADING MACHINE 9 Sheets-Sheet 9 Original Filed Sept. 10, 1948 lNvE NTORB CHARLE5 C. THOMAS Hagar; W CAQPJESI 0EcEA$El7 5y FLORA M. CARNES, ExEcuTmx UNITED STATES TENT O F-F ICE SHOE SOLE GRADING MACHINE Charles C. Thomas, Medford, Mass, and Herbert W.'Carnes, deceased, late of SwampscothMass In); Flora, M. Carries, executrix, Swampscott,

ass.

Continuation of application Serial No. 48,735,

September 10, 1948. This application September 13, 1950, Serial No. 184,536

3 Claims. (Cl. 33-448) This invention relates to grading machines of edges of the blank. Another object of the inthe class in which shoe .soles, taps, and similar vention is to provide edge measuring apparatus blanks of leather are subjected to conventional of the type described which may be adjusted to grading operations wherein the term grading deal with a range of sole blank sizes and which may include skiving or evening a blank to a be operated in timed relationship with re- .dimension corresponding to its thinnest section; spect to the feeding of shoe blanks through the also stamping .or marking each blank with a grading machine. character indicative of its thickness grade; and These and other objects and novel features will also indicating on a visible indicator the grades be more fully understood and appreciated from of various blanks, as well as sorting or classiiylo the following description of .a preferred embodiing the .blanks in accordance with their grade ment of the invention selected for purposes of measurements. illustration and shown in the accompanying In shoe making it is essential for best results drawings, in which in the completed shoe that theexposed edge por- Fig. l is a full-sized development of two imtions of the sole or tap be of substantially uniproved calipering rolls of the invention lying in form thickness, especially at the opposite side spaced relation and presenting outer circumferedges of the forepart of the sole. Actually, it ential gauging surfaces which have been broken is the thickness of relatively narrow marginal 011 for convenience. A shoe sole blank has been sections included along the opposite side edges indicated in dot and dash lines in the position of a sole which determine most accurately the which it assumes when passing over the caliperthickness grade of the sole, and to which thicking rolls, and two additional horizontal dot and ness the sole, as a whole, should be evened or dash lines indicate the zone of grading along skived down. which the calipering action of the rolls is effec- Difficulty has always been encountered in tive in positioning conventional setting mechacarrying out grading operations with caliper- :5 nism and indicating mechanism in a grading ing rolls so as to accurately deal with these irmachine; regular marginal side edge sections, since the Fig. 2 is a fragmentary side elevational View latter not only vary in thickness, but deviate of a grading machine with which the improved along two opposite curves, thus necessitating edge measuring mechanism of the invention has both vertical movement of the calipering rolls been combined; and some lateral movement to properly follow Fig. 3 is a cross-sectional View, partly in elevathe contour of the edges and maintain a path tion, taken on the line 3-3 of Fig. 2, and in of Contact of substantially uniform marginal which view end portions of the grading mechawidth. Such apparatus as has been devised to nism have been broken oii for convenience; follow the marginal side edge sections is not 55 Fig. i is a detailed cross-sectional view taken practical to use and, as a result, there often on the line 4-5 of Fig. 3; occurs a certain amount of waste of leather re- Fig. 5 is a plan view taken on the'line 55 of moved in the skiving operation and, in some Fig. 2; cases, there may develop failure to accurately Fig. 5 is a detail side elevational view of one of skive the marginal edge sections to a thickness 3:) th shaft which support the rolls shown in actually corresponding to the thinnest point Fig. 5;

therein. Fig. 7 is a front elevational view of the gauging The present inVeIllYiOll s Coneemed With the roll construction of the invention, further illusproblem indicated and aims to provide an trating in cross-section a sole blank entered beproved apparatus for carrying out accurate edge tween th calipering 11 measurements of a shoe blank without waste Fjg g i i similar to Fig. 7 in which the nd Withou lo of ac y in the skivins 0pgauging rolls have been rotated into a more aderation. Another object of the invention is to anged edge measuring position;

provide edge measuring mechanism which will Fig 9 shcws a mgdified form of edge measurm su O y relatively narrow marginal ing or calipering roll in which a curved circumtions of a blank; nd which will follow the conferential section is provided on the outer cirtour of a blank having an irregular or non-- cumferential urface of the roll;

re ilin r Side g a W111, fi, mead Fig. 10 is a vertical, cross-sectional view of ore a marginal area of substantially uniform another form of grading machine with which the breadth irrespective of the deviation of the side gauge measuring mechanism of the invention has been combined to provide for manual feeding of a shoe blank therethrough;

Fig. 11 is a front elevational view of a grading machine and edge measuring mechanism similar to that shown in Fig. and indicating the position of the gauging rolls just prior to introduction of a sole blank thereon;

Fig. 12 is still another view of the apparatus shown in Figs. 10 and 11 and further indicating the gauging rolls in an operative position with a grading cycle and particularly showing one position of the clutch driving means;

Fig. 13 is a cross-sectiona1 view, partly in elevation, taken on the line Iii-13 of Fig. 11; and

Fig. i l is a partial cross-section, in side elevation, taken on the line I i-hi of Fig. 11.

In accordance with the invention we have devised an improved blank feeding and gauging roll construction for grading machines. Included in the gauging roll construction is a pair of novel calipering rolls which constitute an upper set of rolls adapted to operate in conjunction with a lower set of detector rolls.

Essentially our improved calipering rolls comprise a pair of roll members arranged in spacedapart endwise relation to one another with each roll being formed with a special circumferential edge measuring surface. The latter surfaces are designed to overlap relatively narrow opposite marginal edge sections of a leather blank in a predetermined manner so as to maintain paths of rolling contact of substantial uniform marginal width.

Each of the edge measuring surfaces is formed with an irregular inner boundary of definitely limited extent. The boundary terminates along a line which deviates in an axial direction as it extends circumferentially around its respective roll 50 as to form a curve substantially corresponding to the curvature of the particular side edge of a blank which it is designed to overlap.

Preferably these novel edge measuring surfaces are formed by relieving circumferential portions of the calipering rolls and the invention will first be described having reference to such a type of construction, combined with one standard form of grading machine in which conventional grading mechanism is utilized. It should be understood that the gauging r011 construction of the invention either in the form about to be described in detail or in other forms, may be combined with and applied to a great many types of grading machines well known in the art, and is in no sense to be regarded as being limited to the single form of grading machine suggested in the drawings.

Referring more in detail to the drawings and especially to Figs. 2 and 3, we have illustrated a conventional form of grading machine, such as is disclosed in Pat. No. 2,325,011, issued to Metcalf in 1943. The structure shown in Figs. 2 and 3 is, in part, similar to the structure appearing in Fig. 6 of the Metcalf patent above mentioned.

In the drawings and specification of the present invention reference characters below numeral 100 are duplicates of numerals used in said Metcalf patent. The function of such parts is the same as in the patent referred to and since the operation of the grading mechanism is well known to the art and is clearly set forth in the patent referred to, no further detailed description will be furnished here other than to note that the gauging roll construction of the invention provides for a vertical roll displacement to actuate one or more pivoted arms connected to the mem.. bers which move and set the grading mechanism in varying desired positions of adjustment for skiving and other operations indicated above.

Considering in greater detail the gauging roll construction of the invention shown in Figs. 2 and 3, there is included therein a pair of upper calipering rolls having circumferential edge measuring surfaces It]! and I02. The rolls are fixed on a common drive shaft 3 rotatably supported at either end in two frame portions of the grading machine, as shown in the drawings. Each roll is secured by means of set screws, as 103 and I04, which engage in the respective grooves lfleand I06 to provide for adjustment of the calipering rolls toward or away from one another, as desired.

It should be understood that the extent of grading operations may vary in accordance with the type of sole blank grading. In utilizing the improved calipering rolls of the invention it should be borne in mind that gradin the sole blank may. in some cases, as in any outer sole grading, take place over a portion only of the blank, as represented by the part included between the dot and dash arrow lines A and B of Fig. l. The remaining portions of the blank, including the toe and heel sections, are not graded here as it is immaterial whether or not the thickness of any one of these portions falls below the minimum thickness occurring in the grading zone defined by a rows A and B.

In accordance with the invention, portions of the roll peripheries are relieved along two oppositely curved lines Hill) and I02b to form the recessed areas lllla and 102a, as shown in Figs. 1, 7 and 8. It will be noted that these recessed areas constitute respective inner boundaries of the two opposite edge measuring surfaces It]! and I02. The curved lines IOlb and I021) are selected with reference to the curvature of the side edge portions of the shoe blank B so that each edge measuring surface terminates alon a line which deviates in an axial direction as it extends circumferentially around its respective calipering roll to form a boundary curve substantially corresponding to the contour of an adjacent curved edge of the blank, as suggested in Fig. 8.

It will readily be seen that by adjusting the calipering rolls toward or away from one another on the shaft 3 it is possible to take care of a range of blank sizes and to locate the respective boundary curves in any desired overlapping position with respect to marginal side edges of the blank B with the latter member being supported on the lower detector rolls l25l25 arranged in gaugin relationship below the calipering rolls. There may thus be realized a position of register such that the overlapping must occur along a marginal area of approximately uniform width, as illustrated in Fig. 8.

The blanks are fed to the grading machine heel end first, and therefore the calipering rolls will be set to provide a margin of overlap which w ll be suitable for overlapping those opposite curved side edges occurring nearest the heel end of the blank. Actual feeding of the blanks may be carried out by hand feeding individual blanks, or by automatically feeding the blanks. In the structure shown in the drawings it is mandatory that the calipering rolls make one revolution only for each blank feeding and grading cycle. Other arrangements may be resorted to wherein, for example, the edge measuring surfaces of the invention are repeated around a single roll periphery.

Thus, in the apparatus illustrated in Figs. 2

shouldered end H3 is adapted to engage in the yoke ends lite and Illa, as shown in Fig. 3. The other end is shouldered and threaded to receive a wringer type gear H4 and nut H5. A key I I6 engaging in the keyway of the gear I I4 and a keyway located in the shouldered portion of the shaft II2 securely engages the gear II4 With the shaft H2.

The gear ll l engages with a similar type gear III which is keyed at H8 to the main drive shaft 3. and the upper drive shaft are identical, as are the shaft and internal parts of the lower rolls, the lower roll parts being interchangeable. On the main body of the lower roll shafts H2 we have provided a key member H9 on the end of p the shaft adjacent the gears H4.

Around the shafts H2 are journalled sleeve members I20. The sleeves I20 are provided with shouldered ends IZI which are journalled in the yoke portions HM and Illa. of the levers III! j and II I. In the shouldered end of the sleeves I2I we have provided recesses I22 comprising passages within which the key I IQ of the shafts II2 turns without opposition, with exception of a key I23 or blocking member against which the I shaft key II9 engages under certain conditions, as will be explained further along in the specification.

The set screws I24 secure the sleeves I29 to the lower detector rolls l2 5-I25 and it will be noted tha t set scr s 2 d not e a e h a t I I2 but merely secure rolls I25 to the sleeves I2 0, the sleeve moving freely on the said shafts. In the position shown in Fig, 4 the shaft key I I9 is engaged with the key portion I23 of the sleeve I which, in turn, is secured to the lower detector rolls I25. This is the relative position of the members of the lower detector roll assemhly in a r in ra o J s rior t en ry f t o blank between the upper and lower sets of rolls.

It will be observed that the lower detector rolls are not rotating continuusly but/assume a position closely corresponding to that shown in Fig. 4. When the blank enters the nip of the rolls the upper calipering rolls are driven by the shait 3 I in a clockwise direction, as viewed in Fig. 4, and

the blank then becomes a dr vin member operating against the rolls I25. The gears H4 and ill stay in mesh without jamming but the key portion I23 moves away from the shaft key II9 on the sleeves I20. As soon as the blank passes out from the rolls the gears H4 and II! again become eifective and shaft key I I9 moves around and engages the key portion I23, thereby turning the sleeve and the roll I until the rolls come to rest in the starting position shown in Fig. 4.

The upper calipering rolls may or may not turn continuously, depending on the particular construction of the specific driving mechanism in the rest of the grading machine. calipering rolls may turn at a constant rate of speed and the respective functions of the grading indicators and other skiving apparatus may be accomplished during the interval occurring between the time when upper calipering rolls The drive on each of the lower rolls For example, the

ill)

rolls I25.

6 leave one blank and the time when they engage the xt su c ed n blank ro the hopper This is merely a matter of driving ratio between the shaft 3 and other parts of the machine, involving well known engineering factors and not a part of the present invention.

In Figs. 10 to 14, inclusive, we have shown a further adaptation of the drive and calipering rolls to a manually fed grading machine which may or may not be included with skiving opera tions. This adaptation can be used with any one of numerous grading machines in which manual or semi-automatic construction is used. As viewed in Fig. 10, the main drive shaft I26 is engaged with the same wringer type gears already described by means of the keys H8 in the same manner illustrated in Fig. 3. The upper calipering rolls are identical with those previously noted and all mechanism in the lower detector roll construction is exactly the same as heretofore described.

A new and different structure is provided in connection with a timed cycle drive for the rolls and in the means for starting a grading cycle With a desirable cooperative relationship existing between the edge measuring surfaces Iill and I02 and the timed cycle drive. Another novel structure is provided in the take-off drive to related parts of the grading machine.

The timed cycle drive operates through intermediate gear I2l which is meshed with the gear I28 keyed at I29 to the main drive shaft I26. On the other end of the main drive shaft I26 there is provided an intermittent extension drive shaft I30 on which is keyed a gear I32 at point I3I.

In operation, the extension shaft I39 is in continuous motion and the gear I32 may be connected with a motor drive or a belt driven pulley may be substituted for the gear I 32, or any other desiredform of power coupling may be used. On the end of the shaft I26 is a special clutch member I33 being keyed to the shaft I23 by means of the key I34. The clutch member I33 is provided with an internal recess I35 and faced with a friction lining I33. The extension shaft I30 is jeurnaled in a bracket I3! attached to the frame of the machine and has a shouldered body portion I38 and an internal recess I39 journaled around the reduced end I49 which is an extension of the main shaft I26.

Around the end of the shaft portion I lll adjacent the clutch portion I33 is a longitudinally slidable clutch cone I ll being slidable on the shaft member I38 by means of the key I42 fixed in the shaft extension member I49 and engaging in a slidewa-y provided in the cone clutch member I4I. The complete clutch is of the simple cone type, as shown in Fig. 10. Rotatably and slidahly mounted on the shaft portion I33 is a yoke ring Hi3. Between the cone member I4I of the clutch and the ring M3 is a helical coil spring I44. The spring I l normally maintains the ring out against the hub of the bracket I31 with insufficient pressure against the cone portion I ll to turn the clutch member I33 and shaft In this normal or neutral position the extension shaft I39 and clutch cone member l4! idles without any movement of the rolls Illl, I02, or No movement of these rolls takes place until a sole blank is presented to the rolls for a grading operation.

Pivoted on a stud I45 mounted in an offset boss type bracket I45 which is fixed to the side of the machine, is a lever hub I4] having laterally extended lever arms (see Figs. 11 and 12). The lever I48 operates the clutch mechanism and the lever I49 carries the trip mechanism which operates lever I48 and starts the machine on a grading cycle.

On the end of the lever I49 is an upwardly extended portion I50 and an inwardly extended portion iI, the end of which terminates in fork I52 between the sides of which is rotatably mounted a roll member IE3. The roll I53 is positioned approximately midway between the two lower detector rolls and normally above the table surface I54 over which the blanks are fed so that when a blank is pushed over the trigger roll I53 and into the nip of the upper and lower gauging rolls the lever arm I49 is depressed and the rolls start to turn due to action set up by the movements of parts influenced by the lever arm I48 which will now be described in detail.

Lever arm 55 is turned up at approximately ninety degrees at I54 and again turns at ninety degrees to terminate in the upstanding yoke member I55 and yoke arms 5%. The yoke arms I56 are provided with rolls I5? which engage in the annular groove I58 provided in the ring member I43. Branching off from the lever arm portion I54 is another horizontal arm I53 having a ninety degree upturned arm I55 which has a right-angled extension portion in the form of a yoke or fork member I6 I within which is journaled a roll member I62. This apparatus is utilized to effect a timed operating cycle bearing a definite relationship to the edge measuring surfaces IIlI and I02. Thus when the apparatus is in a normal position, as shown in Fig. 11, the roll I62 is at one end of a track I63 extending partway around the inner face of the outer flange of the clutch member I33. This position is in accordance with the invention chosen and constitutes the stop and start point of the rolls It I, I62 and I25 in making one complete cycle.

In operation, a blank of sole leather is pushed along the bed I54 of the machine over the trigger roll I53 into contact with the upper and lower gauging rolls. This operation depresses the trigger roll I53, tilting the lever I49 down and the lever I48 up. Simultaneously, the roll I62 is pulled out of the track I 63 on the clutch member I33 from the position shown in Fig. 11, and the ring I43 is urged against the spring I44, causing the cone member I4I to frictionally engage the member I33, thereby starting the shaft I26 to rotate.

The wringer gears II! on the shaft I26 engaging the wringer gears H4 on the shafts II2 of the lower rolls turns the lower rolls in a reverse direction, pinching the blank B therebetween and the start of the grading operation takes place. So long as the blank B is over the roll I53 the lower rolls continue to turn because the clutch members are engaged and the extension shaft I30, which is always in continuous operation, rotates the drive shaft I26. The overdrive feature of the lower rolls I25 permits these rolls to operate in the manner of idling gears without driving force being applied through the wringer gears II! and The blank 13 progresses through the grading operation and beyond until the toe end of the blank passes over the trigger roll I53 which is approximately the point it leaves the rolls IUI, I02 and I25. The blank is now passed to the skiving operation if the machine is provided with skiving apparatus, an operation with which the present application is not concerned.

Upon the release of the trigger roll I53, the spring I44 forces the ring I43 back and depresses the lever arm I48, causing the roll I62 to press against the inner face of the clutch member I33 and drop into the track I63. The movement of the ring I42 backwardly and the dropping of lever arm I48 does not take place immediately when the sole blank B leaves the roll I53 or until the roll I62 reaches a point permitting it to drop into the track I63. This point is slightly in advance of the stopping point I'I5 during which time the detector rolls are finishing their cycle. During this period after the blank B leaves the detector rolls, the gears III and II 4 are again active and the lower roll shafts I I2 rotate faster than shaft I26, causing the key member II9 to catch up with the key member I23, at which time the rolls I25 are driven by the gears I I4.

During the time that the spring I44 is compressed to a maximum degree, the roll I62 turns on the face of the clutch portion I33. At the point at which the blank 13 moves out of contact with the roll I53, the full force of the spring I44 is exerted on the roll I62 and shortly thereafter the roller I52 drops into the track I63 and befor the the calipering rolls have continued to rotate and reach a point corresponding nearly to the starting point of the cycle. Actually a very short movement of the rolls must take place after the roller I62 drops into the track I63 and before the roll I62 comes to rest against the abutment I75 at the end of the track.

In accordance with the invention the several parts referred to are so constructed and arranged as to control the short movement of the rolls after the blank moves away from the nip point. Specifically, the movement is controlled so that those parts of the edge measuring surfaces IIlI and I02, first contacting the shank end of a blank, will lie in a predetermined relationship to those points at which the inner curved boundary lines I 0 lb and I022) start to deviate and, therefore, the curved edges may be brought into register with the corresponding curved edge portions of the blank B.

There is thus achieved a timed cycle of operation by which the curved boundaries of the edge measuring surfaces may be registered with correspondingly curved edge portions of the blank and this relative positioning may be successively repeated with preciseness and accuracy over a repeated number of cycles of operation without material deviation.

The practical application of the novel curved edge measuring surfaces of the invention, therefore, may be realized to the fullest extent with attendant advantages in the actual gauging operation so that gauging is confined to marginal edges of uniform width in the manually fed operation.

The stopping of the roll I62 against the abutment at I'I5, above referred to as the stopping point, abruptly terminates the rotation of the rolls IIJI and I02. The dwell or track I53 in the clutch member I33 may be only of limited. length or may be extended, as desired, to suit varying conditions determined by the blank and the portions of the blank which are to be gauged. When the clutch friction surfaces are released from contact with one another, the extension shaft I39 and gear I32 continue to rotate in the same manner as before the clutch became engaged.

Our new type calipering rolls, with particular reference to the upper curved track rolls, is ideally suited for a certain brand of square cut soles. It is not necessarily limited to such soles, however. A range of sizes are cut with the same curved knife in a certain conventional machine, hence all sizes of this type of blank have the same curve or swing. To change sizes on a machine using our improved calipering rolls, a simple adjustment of the lateral spacing of the upper rolls is all that is necessary. In any event, an assortment of a very few rolls would probably cover the entire field.

It should be borne in mind that perfectly cylin drical rolls of the proper diameter may be used, such as the roll illustrated in Fig. 9, indicated by the numeral I00, and a curved strip Isl may be attached to the circumference of the roll. I to produce the same effect as in rolls l0! and 102. The strip [8| may be integral with, or separate from the roll I80. Rolls I01 and I02 may berelieved along the whole face of therollinstead of only for a certain depth below the curved edge, and various other types of construction may be resorted to in forming the novel curved edge measuring surface of these rolls.

We have shown two types of uses for these new calipering rolls, such as in a semi-automatic machine and in mechanism in combination with the curved rolls adapted for use with old type grading machines, and it is to be understood that while we have shown combined mechanism in use with the new rolls, yet the scope of the invention may be much broader, limited only by the scope of the appended claims. This application is a continuation of copending application Ser. No. 48,735, filed September 10, 1948 and now abandoned.

Having thus described our invention, what we desire to claim as new is:

1. An improved grading machine for grading a shoe sole blank having opposite curved side edges included in the forepart, thereof, said grading machine comprising a pair of detector rolls in endwise spaced apart relationship, a second pair of calipering rolls located above the detector rolls in suitable gauging relationship to receive the sole blank therebetween, said calipering rolls being formed with circumferential edge measuring surfaces adapted to overlap marginal edges of the forepart of the sole blank, each of said edge measuring surfaces terminating along a line which deviates in an axial direction as it extends circumferentially around its respective calipering roll thereby to form a curve substantially corresponding to the contour of an adjacent curved edge of the forepart of the sole blank, and said machine further including independently driven shafts for the detector roll, gear means for driving the shafts in response to rotation of the calipering rolls, each of the detector rolls being operatively connected to its respective shaft by means of a sleeve member, said sleeve members being mounted about their respective shafts for rotation through a limited arc of rotation.

2. An improved grading machine for grading a shoe sole blank having opposite curved side edges included in the forepart thereof, said grading machine comprising a pair of detector rolls in endwise spaced apart relationship, a second pair of calipering rolls located above the detector rolls in suitable gauging relationship to receive the sole blank therebetween, said calipering rolls being formed with circumferential edge measuring surfaces adapted to overlap marginal edges of the forepart of the sole blank, each of said edge measuring surfaces terminating along a line which deviates in an axial direction as it extends circumferentially around its respective calipering roll thereby to form a curve substantially corresponding to the contour of an adjacent curved edge of the forepart of the sole bank, and sad machine fulrther including independently driven shafts for the detector rolls, gear means for driving the shafts in response to rotation of the calipering rolls and mechanism for operatively connecting the detector rolls to their respective shafts in one position of rotation thereof.

3. A structure according to claim 2, including means for rotating the detector rolls at a rela tively faster rate of speed than the respective detector roll shafts when the shoe sole blank is passing between the calipering rolls and the detector rolls.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,382,689 Stewart June 28, 1921 1,790,559 Swift Jan. 27, 1931 1,820,010 Cogswell Aug. 25, 1931 1,937,815 Denne Dec. 5, 1933 1,963,850 Johnston June 19, 1934 2,047,267 Hood July 14, 1935 2,187,204 Johnston Jan. 16, 1940 2,207,237 Bretholtz July 9, 1940 2,325,011 Metcalf July 20, 1943

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