US2671333A - Skiving machine - Google Patents

Description

March 9, 1954 F. 0. DE MILLAR SKIVING MACHINE 3 Sheets-Sheet 1 Filed Sept. 2, 1950 Wm M INVENTOI P Ed 0. pew Wm 7m 5y ATTORNEY March 9, l54 F. 0. DE MILLAR 2,671,333 SKIVING MACHINE Filed Sept. 2, 1950 3 Sheets-Sheet 2 F/G3 T4 IN [/5 TOR F L 0. lull/u 8V w A TTORNEV March 1954 F. 0. DE MILLAR SKIVING MACHINE 3 Sheets-Sheet 5 Filed Sept. 2, 1950 ATTORNEY Patented Mar. 9, 1954 SKIVING MACHINE Floyd 0. De Millar, Framingham, Mass, assignor to North American Research Corporation, Cambridge, Mass, a corporation of Massachusetts Application September 2, 1950, Serial No. 182,912

3 Claims.

This invention relates to an improved method and machine for carrying out skiving operations and especially skiving operations of the type commonly utilized in connection with evening leather shoe sole blanks and various other articles made of leather or similar products where -the term evening defines cutting the leather blank in a plane approximately parallel to the grain side of the leather.

In presently employed skiving methods and apparatus it is customary to provide a cutting member of relatively solid construction rigidly fixed in a stationary base, and to fee-:1 a leather blank across the cutting member in order to remove unwanted portions of the blank. It is. of course, more dificult to force the leather across the stationary cutting member than would be the case if the cutting member were drawn transversely across the leather during a forward feeding movement of the latter. For this reason the machines referred to must be provided with means for very rigidly holding the blank during the cutting operation. Moreover, even with the best equipment available there some times occurs a faulty skiving operation resulting in gouging or other nonuniformity in the cutting operation. Some attempts have been made to move the cutting member, but they have, in almost all cases, been without success owing to the difficulty of properly supporting a moving cutter member.

The present invention is concerned with the problem indicatedand aims to provide improved methods and apparatus for carrying out skiving operations and other cutting operations generally. It is also an object of the invention to provide a simplified type of leather skiving or splitting mechanism wherein some of the heavier elements of construction heretofore used may be eliminated without loss of accuracy in the skiving operation. Still another object of the invention is to provide a method and apparatus for skiving leather blanks with a greater degree of uniformity in skiving than has been realized heretofore.

These and other objects and novel features will be more fully understood and appreciated from the following description of a, preferred embodi ment of the invention selected for purposes of illustration and shown in the accompanying drawings, in-which Fig. 1 is a front elevational view of the skiving machine of the invention;

Fig. 2 is another. elevational View. partly in cross-section, more clearly indicating the shiving mechanism employed in the machine; 7

Fig. 2a is a detail plan view of a, pair of grind- 2 ing wheels arranged to grind the cutting member of the invention;

Fig. 3 is an enlarged fragmentary detail view of roll members employed in conjunction with the skiving mechanism;

Fig. 4 is a cross-section taken on the line 4--% of Fig. 3;

Fig. 5 is a detail plan view of adjustment mechanism for raising and lowering the roll members;

Fig. 5a is a detail elevational view of a modified type of curved cutting member;

Figs. 6' and 7 illustrate a modified form of skiving mechanism in which an oscillatory movement of the cutting member is carried out; and

Fig. 8 is another modified form of the invention in which the cutting mechanism is shown applied to a leather blank in an inclined position such that the cutting member meets the leather blank at an angle.

The present invention is based on the novel concept of causing a cutting member to move along a curved path and at the same time feeding a leather blank so as to produce a curved section which generally coincides in shape with the curvature of the cutting member and which section may be rigidly held and urged against the cutting member as the latter moves along the said curved path. It is also contemplated that the curved section of blank after being skived may be subjected to a straightening operation. One suitable arrangement for moving the cutting member comprises the combination of a curved cutting blade with a revolving wheel in which the blade is rigidly held, although it is not hi tended that the invention be limited to this specific structure.

The feeding action may be carried out in a preferred embodiment of the invention by means of a pair of feeding rolls, one of which is formed with a peripheral surface which is convex with reference to a plane passing through the axis of the roll and the other of which has a peripheral surface which is concave with reference to a plane passing through the axis of that roll. Moreover, the concave surface is chosen so that it is substantially complementary with the convex surface noted and the arcsof curvature of these peripheral surfaces are chosen to coincide with the curvature of the cutting member.

The rolls are forced against one another with a sole blank therebetween and they perform several distinct functions including;

(a) The temporary shaping of the blank. into a. curved form similar to the curvature of the cutting member;

(b) Flattening the blank and pressing out of all wrinkles or creases in the leather; and

(c) The actual supporting and feeding of the blank against the cutting member.

The result of this roll arrangement is to provide a practical instrumentality with the aid of which a rotary type cutting member can be readily drawn across the blank as the latter member is fed forwardly. It will be evident that the ability to move the cutting member greatly facilitates the skiving operation, as well as providing other advantages.

Considering in detail the structure shown in the drawings, there is illustrated a frame having a base I from which extend vertically upward front and rear sides l2 and I4, respectively. Through the front side I2 has been cut an opening [6 providing access to the bottom enclosure comprised by the side portions of the frame. Transversely disposed through the front and back sides of the frame is a shaft l8 which is adjustably secured for movement in axial directions in bearings 20 and 22. One end of shaft 18 is provided with threads 24 and the outer extremity of the shaft is formed with a square end portion 26 permitting the shaft to be screwed in and out in the frame to assume any desired position of longitudinal adjustment.

At its opposite end the shaft l8 has supported thereon a wheel 30 mounted for rotation in a ball bearing assembly 28. The wheel is held on the shaft by means of a fastening member 32, as is more clearly shown in Fig. 2 of the drawings. A motor 34 drives a belt 36 which, in ttu'n, drives a pulley 33 on a hub portion 48 extending from the outer side of the wheel 31!.

Adjustably secured around the inner side of the wheel 30 is a curved cutting member 42 which preferably comprises an endless band of tempered steel, the outer edge of which is sharpened to provide a curved cutting edge. The cutting member in the curved shape shown in Fig. 1 is solidly held in place in recesses in the wheel 30 by means of wedge pieces 44 which may be tightly drawn against the rim of the wheel 30 by adjustment bolts 46, for example. It may also be desiredto use a straight cutting member which is formed with the proper curved shape during its use.

Cooperating with the cutting member 42 is a pair of feeding rolls '2 and 54, respectively, which are arranged in feeding relationship directly in front of the cutting member 42 so that the nip point of the rolls, with reference to a sole blank passing therebetween, occurs in close proximity to the cutting edge at a point approximately at the top of the path of movement of the wheel 30.

As will be seen from an inspection of Figs. 1 and 2, the rolls 52 and 54 are supported on respective shafts 56 and 58 mounted in upper sections of the frame sides l2 and M, as shown in Fig. 1. The motor 34, through a worm 66, drives a speed reduction mechanism 62 of conventional character, connected to which is a vertical shaft 64. The shaft is received through an extension 66 of the frame and has fixed at its upper end a bevel gear 68 which is adapted to mesh with another gear fast on a stub shaft 72. Also secured to this shaft is a small gear 14 in mesh with another gear 16 mounted on a shaft 86 which extends through the sides of the machine and has centrally secured thereon a pulley 15. A driving member, preferably a silent chain drive 82, is receivedabout the pulley and extends forwardly in driving relationship around the roll 54 in a central recess 88, formed in said roll for this purpose and in which are located teeth. The chain may be formed with special curved back sections, if desired. Also in mesh with gear 16 is a small gear 18 on a stub shaft 19 received in the frame of the machine. Fixed at one side of the gear 18, on the same shaft with it, is a pulley carrying a belt 8| which drives another pulley 95, better shown in Fig. 2 of the drawings.

With reference to the feeding roll structure illustrated in Figs. 3 to 5, inclusive, it will be observed that these rolls are mounted, one above another, with the upper roll 52 being formed with a concaved peripheral surface 52a and with the lower roll 54 being formed with a convex peripheral surface 54a coincident in its arc of curvature with the shape of the concave surface of roll 52. This arrangement of complementary roll surfaces may, if desired, be modified in various respects.

An important feature of the invention is the construction of the rolls of the complementary curved surfaces whose arcs of curvature, considered longitudinally of the respective rolls, are chosen to substantially coincide with the curvature of the cutting member, by means of which arrangement the same curvature may be imparted to a leather blank to be forced against the cutting member.

It is pointed out that by holding the cutting member in a curved position, a substantial increase in rigidity is realized and likewise the leather blank itself, when held so that the nip point of the rolls is very close to the cutting edge, develops an increased degree of stiffness which will permit a smooth cutting action to take place.

The rolls are normally positioned in slightly spaced-apart relationship so that a leather sole blank may be introduced therebetween. In accordance with the invention I also provide a relatively strong spring mechanism for yieldably supporting the roll 54 and for resiliently urging the roll 54 against the roll 52 when a sole blank is in place between the peripheral surfaces. Numeral 89 refers to two vertically disposed coiled springs received in mountings 92 which support the ends of shaft 58. As noted in Fig. 2, the shaft 56, bearing on roll 52, is normally held in a fixed position of adjustment, although it may be raised and lowered to accommodate different thicknesses of sole blanks. A suitable mechanism for making vertical adjustment has been provided including two vertical screws 9| threaded into bearing members 93. At the upper ends of the screws are worm gears 94 and 96. which gears are driven by a hand operated worm 98 through a knurled wheel I00.

At the right-hand side of Fig. 2 there may also be provided means for straightening the leather after it passes through the curved rolls, and for this purpose there may be used a pair of parallel guide plates 89 and 90 supported on some convenient part of the frame. Also, there may be provided a pair of grinding wheels and 37 (Fig. 2a) arranged to constantly sharpen the curved cutting member. These grinding wheels may be of well known construction and may be supported at any point around the cutting member.

In operation a shoe sole blank is placed on the conveyor chain 82 which moves the blank ahead with the forward edge of the blank passing between the nip point' of the rolls 52 and 54. Im- Inediately the sole blank is squeezed between the two rolls and completely flattened out to remove aIl creases or wrinkles which may be present in the contacted areas, and for this purpose a pressure of in the neighborhood of 600 lbs. per square inch has been found to be necessary. Simultaneously the portions of the sole blank engaged between the rolls will be found to take the shape of the roll peripheries and thus assume a curved shape which corresponds to the arc of curvature of the cutting member 42. Also, by correctly locating the cutting edge of the cutting member just in front of the nip point of the rolls 52 and 54, it is found that the curved section of the blank may be very rigidly held with sufficient supporting action to permit the curved edge of the cutting member 42 to be drawn thereacross and carry out a highly uniform skiving operation. Skived material I 92 from the blank B is deflected downwardly into the bottom of the enclosure constituted by the frame.

In determining the correct position of the cutting edge with relation to the nip point of the rolls, it has been found that there are limiting factors present which must be taken into account. If the blade is too close to the nip point it tends to prevent the forward edge of the sole blank from entering between the rolls. If, on the other hand, the blade is far in front of the nip point, the front edge of the leather may buckle and gouging will occur. In actual use of the mechanism of the invention, desirable results have been obtained by locating the cutting edge with reference to a vertical center line passing through the nip point of the roils so that a richnite clearance of approximately 1% of an inch is provided with some small deviation being permissible.

In providing a suitable cutting member I may employ in place of the endless band a number of curved blade sections 42a, which sections may be mounted around a wheel 36a, as suggested in Fig. 5a, for example. Likewise, the path of movement of the cutting means may be varied in several ways. For instance, a segmental blade I03, Figs. 6 and 7, may be mounted on a blade support I H), as shown in said figures, and solidly locked in place by a wedge arrangement, such as that already described.

The blade support H is formed with a hub I I2 pivotally received on a shaft 1 t4, the opposite ends of which are held in fixed bearings H6 and H8. The blade support H0 is formed with an arm i I I through which is formed an opening l i3 and an eccentric rod H5 is located through the opening ii?) and when rapidly rotated about its longitudinal axis will oscillate the blade support H0 at any suitable rate of oscillation. For some types of operation it is contemplated that the oscillatory type of blade movement may be preferable, and in this connection it is pointed out that with a high speed oscillation there may be induced an important vibratory effect which will even further facilitate passage of a blade through the leather blank.

It may also be desired to apply a cutting member of either the endless band form or segmental form, in an angularly disposed manner with respect to the leather blank in order to vary the cutting action. One such arrangement has been provided in Fig. 8 wherein there is shown a cutting wheel l whose axis of rotation is along a line occurring at an angle to a horizontal plane. One advantage to be derived from thus angularly positioning the cutting member is to increase the angle between the upper roll and blade through which the blank B may pass. In effect, the cutting edge may be located slightly closer to the nip point in this case. Another arrangement might consist in a conically shaped blade to also provide angular cutting with a curved blade.

It will be evident that the invention provides a practical and efiicient method and apparatus for carrying out skiving operations on leather blanks, as well as various other sheet materials, such as impregnated fibrous products, and the like. A faster and cleaner skiving operation is thus made possible and greater uniformity in the result of the product is realized. A very important consideration is the reduction in cost of the mechanism brought about by less need for heavy reinforcing structure, such as is now necessary in presently used skiving mechanisms. Also, the rotary type cutting member adapts itself very effectively to grinding.

While I have shown preferred embodiments of the invention, it should be understood that various changes and modifications may be resorted to in keeping with the spirit of the invention as defined by the appended claims.

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

1. An improved cutting mechanism for use in cutting a sheet material, comprising a frame, a driven cutting member movable in the frame along a curved path, means for feeding the sheet material so as to continuously produce a curved section which is urged against the cutting memher as the latter member passes along the said curved path, and means for oscillating the driven member.

2. An improved skiving machine for use in skiving a leather shoe sole blank, comprising a driven cutting member consisting of a segment of a cylinder, pivoted support means for holding the segmental cutting member in a position to engage with the leather sole blank, roll means for feeding the leather blank so as to continuously produce a curved section which is urged against the segmental cutting member, and means for oscillating the segmental cutting member.

3. A structure as described in claim 2, in which the support means for the segmental cutting member includes a pivoted arm, and said means for oscillating the segmental cutting member consisting of an eccentric member engageable with the pivoted arm.

FLOYD 0. DE MILLAR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 875,528 Hirth Dec. 31, 1907 944,103 Parmenter et a1 Dec. 21, 1907 1,121,717 Davenport Dec. 22, 1914 1,200,066 Alexander Oct. 3, 1916 2,228,442 Coleman Jan. 14, 1941 2,250,497 Ray Jul 29, 1941 2,291,757 Potter et a1 Aug. 4, 1942 2,374,836 Ruedebush May 1, 1945 FOREIGN PATENTS Number Country Date 311,239 France Mar. 4, 1919 373,065 Germany Apr. 7, 1923 652,226 France Oct. 22, 1928

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