US3129578A

US3129578A - Leather shaving machine

Info

Publication number: US3129578A
Application number: US189048A
Authority: US
Inventors: Arthur H Horn; Henry W Bode
Original assignee: CHAS H STEHLING CO
Current assignee: CHAS H STEHLING CO
Priority date: 1962-04-20
Filing date: 1962-04-20
Publication date: 1964-04-21
Anticipated expiration: 1981-04-21

Description

April 1964 A. H. HORN ETAL LEATHER SHAVING MACHINE BLADE SPACING NOT TO EXCEED L25" 'QMMW Ari/5212' .Efivrzz girl) W300! Filed April 20, 1962 in dates This invention relates to leather shaving machines in which a rapidly rotating cylinder with helical blades thereon pitched in opposite directions from the center of the cylinder toward the ends thereof, performs a cutting or shaving operation upon leather as it is drawn into the machine under the control of the operator. Since the length of the cutting cylinder determines the maximum width of the piece of leather that can be acted upon at one time, it seems but logical that leather shaving machines would be made with cutting cylinders long enough to accommodate the full width of a side of leather, especially since it is obviously advantageous from a production cost standpoint to be able to shave a full width of a side of leather With each pass through the machine.

A side of leather is half a tanned hide. Cow hides are almost always out in two, right down the back bone. Only where unusually large pieces of leather are required, as for table tops, is a cow hide tanned and finished in one piece. Thus tanners think in terms of sides.

To appreciate this invention and fully understand its place and significance to the tanning industry it should also be understood that the shaving operation is performed on the tanned leather (usually chrome tanned) and not the fresh hide; and that the tanned leather is in a wet limp state when it is shaved. Another fact to be borne in mind is that shaving is performed only after the side of the leather has been split. Generally speaking, only sides (or leather) that are intended for use as sole leather are not split.

Splitting is done on machines such as that of the Meyer Patent No. 1,410,703. By this operation the side of leather is split into at least two and sometimes more pieces, at least one of which is substantially uniform in thickness, and since the first split is made with the grain side of the leather against the gage roll, the largest piece obtained is always of the first quality and is the one of substantially uniform thickness. Although the split sides are fairly uniform in thickness the splitting knife does not leave too smooth a surface, so that for use as upper leather this surface must be shaved. Also for this purpose the thickness of the leather must be as close as possible to uniform.

Despite the obvious advantages of performing the shaving operation across the full width of a side, leather shaving machines heretofore available have not had this capacity. An the contrary, the cutting cylinders of shaving machines used by the industry for years have not been much longer than twenty-four inches, which is not even half the length needed to act upon the full width of a side of leather at one time. This severe limitation upon the capacity of leather shaving machines is all the more significant in view of the fact that leather shaving machines have been available for many years, as evidenced, for instance, by the Taylor Patent No. 277,631, issued in 1883.

The lack of leather Working machines with cutting cylinders long enoug to act upon the full width of a side of leather was not due to any inability on the part of the manufacturers of leather working machinery to produce longer helically bladed cutting cylinders. They have been doing this for a long time. The difliculty lay in the fact that with prior shaving machines the operator of the machine could not properly control the entry of the ate J p 3,129,578 Patented Apr. 21, 1964 side of leather into the machine if much more than twenty-four inches of cylinder length acted thereon at one time. The pull exerted upon the side by a twentyfour inch cylinder length was about the limit that an operator could successfully resist and control.

Since sides of leather are much wider than twentyfour inches, the operator had to perform a minimum of four shaving operations on each side. In other Words, he had to feed the side into the machine at least four different times.

The time required for these four shaving operations, plus the fact that considerable skill is required to properly operate a leather shaving machine, made the leather shaving operation a significantly expensive part of the tanning and leather finishing process. The seriousness of this situation has been recognized by the industry for many years. Nevertheless, no one heretofore has been able to solve the problem that kept the attainment of the desired objective from being realized. This invention solves that problem.

To appreciate the problem and its solution, it must be understood that, in leather shaving, it is important that all portions of the sideand particularly the shank and foreleg portions thereofare straightened and smoothed out onto the feed and backup roll before the cutting cylinder contacts it. If this is not done, these peninsular-like portions of the side will be completely or partially cut off, which of course would result in an economic waste. Accordingly, the shaving machine must be so designed and constructed that the operator has a full View of the side as it is fed into the machine, and the machine must feed or draw the side into it, not out of it.

But, most important, the operator must have control over the side at all times, despite the fact that once the side is gripped between the cutting cylinder and the feed and backup roll, the rapidly revolving cutting cylinder exerts a substantial pull upon the side. Since the pull thus exerted upon the side, per unit of length of the cutting cylinder, was such that an operator could not successfully cope with much more than that produced by twentyfour inches of cutting cylinder action, and since the art did not known how to reduce this pull factor without getting into such problems as chattering and uneven shaving, the limitation was generally accepted as inevitable.

The problem to which this invention is addressed namely, that of increasing the capacity of leather shaving machines-was recognized by the patentee Blaney in his Patent No. 1,621,577, issued March 22, 1927; and While Blaney offers a solution to the problem, his machine has the disadvantage of receiving the side (which he calls a skin) to be inserted into the machine in such a way that the operator has no control over the side and cannot see it as it approaches the cutting cylinder. Blaney sought to solve the problem by substituting mechanical means for manual control, which has never been practicable in leather shaving. In presenting his invention, the patentee observes:

In shaving machines, as heretofore constructed, the cutting cylinder has ordinarily been of such a dimension as to present an effective cutting surface approximately twelve inches in length, although more recently larger cylinders have been employed with an effective cutting surface of about two feet in length. In operating with either machine, it is necessary for the operator to shave a portion of a skin and to shift the skin repeatedly in both lateral and longitudinal directions to operate upon adjacent portions, the Whole operation of shaving a skin requiring the greatest skill in order to obtain uniformity throughout all portions of the shaved skin and to avoid the presence of ridges or scores or other lines of demarcation between adjacent areas successively operated upon. Moreover, the shaving of perforated portions of the skin and of the margins, and especially of those parts which form projections or tabs extending from the body portions, make great demands upon the skill and patience of the operator. It is not surprising, therefore, that operators on shaving machines are among the most highly paid employees of leather manufacturing plants.

It is an object of this invention to provide a shaving machine of relatively great capacity, when compared with prior machines, which may be operated satisfactorily by the ordinary workman without the exerecise of expert knowledge.

Although the Blaney patent discloses a leather shaving machine large enough to operate upon an entire side at one time, it achieved its purpose at the expense of foregoing the accepted and proven method of operating shaving machines. For successful leather shaving, the side must be fed into the machine and not out of the machine. Otherwise the operator can not maintain the required control over the side as the shaving operation begins and while it is in progress. Hence, the machine of the Blaney patent is no answer to the problem which has confronted the art ever since leather shaving machines were first produced.

The discovery which led to the invention has made it possible for leather shaving machines large enough to accept and openate upon an entire side at one time, to be successfully operated by a single operator, Without in anywise increasing the amount of pull that he has to exert upon the side in controlling it, as it is fed into the machine-or, in fact, as the shaving operation proceeds. This discovery is simply that the angle and spacing of the helical blades of the cutting cylinder is ciritical, and must be maintained between definite limits.

Although the invention could probably be described without recourse to drawings, since basically the leather shaving machine of this invention does not depart from past practice, except in the critical areas above referred to, it will no doubt be helpful to refer to the accompanying drawing, in which:

FIGURE 1 is a side view of the main portion of a leather shaving machine of this invention; and

FIGURE 2 is a front elevational view of a central portion of the cutting cylinder of the machine.

On this drawing, the numeral 5 designates the cutting cylinder of the machine and the numeral 6 indicates the combined feed and backup roll which holds the side against the cutting cylinder during the shaving operation and which has a solid unyielding work engaging surface.

The cylinder 5, as in all prior leather shaving machines, has helical blades 7 on its periphery, which are pitched in opposite directions from the center of the cylinder, so that as the cylinder acts upon the side, these blades spread the side out toward the ends of the cylinder an operation customarily known as putting out."

The cylinder 5 is journalled in bearings 8, which are mounted in the end frames 9 of the machine, only a portion of one of which is shown in FIGURE 1; and any suitable means is provided for revolving the cylinder in a clockwise direction, as viewed in FIGURE 1, and at relatively high speed. For purposes of illustration, the means for driving the cylinder is shown as a belt 19 trained over a pulley 1-1 which is fixed to the adjacent end of the cylinder shaft. In practice, the cutting cylinder revolves at a speed of between 1750 and 2000 r.p.m.

The edges of the helical blades are kept sharp by a grinding wheel 12 which is mounted on the frame of the machine and which, in operation, travels back and forth along the length of the cutting cylinder.

The combined feed and backup roll 6 is journalled in a swinging frame structure, indicated generally by the numeral 13, for movement toward and from the periphery of the cutting cylinder. The frame structure 13 is pivoted, as at 14, between portions 15 of the end frames 9. Any suitable means may be supplied to swing the frame 13 about its pivotal mounting between closed and open posi- 4 tions. In the closed position the feed and backup roll is directly contiguous to but spaced at definite adjustable distance from the cylinder, holding the hide or other Work H against the blades of the cylinder. In the open position, the combined feed and backup roll is spaced approximately one inch from the periphery of the cutting cylinder.

The swinging frame 13 also mounts a roll 16 which is disposed forwardly of the feed and backup roll, i.e. towards the operator, and spanning the distance between the upper peripheral portions of the

rolls

6 and 16, with its top surface substantially tangent to these rolls, is a transfer table 17. Another table 18 projects forwardly from the roll 16, upon which the operator may place the side preparatory to feeding it into the machine.

The rolls 6 and 7 are power driven by means of a chain 19 trained over a drive sprocket 20 which rotates about the pivot axis 14, and over sprockets 21 and 22, respectively fixed with respect to the

rolls

6 and 16. The drive sprocket 20 is driven from a power source in any suitable manner, as by means of a belt 23 trained over a pulley fixed with respect to the drive sprocket 20.

The peripheral speed of the

rolls

6 and 16 is in the neighborhood of 40 rpm. which, of course, is greatly less than the peripheral speed of the cutting cylinder; and since it is desired that the side of leather or other work being acted upon move into the machine and past the cutting cylinder at the peripheral rate of the feed and backup roll, the surface of this roll is roughened to give it a better grip upon the hide. Since the roll 6 is generally formed of steel, sand blasting its surface provides the desired roughening.

As noted hereinbefore, it has been discovered that if the angle of the helical blades, i.e. the angle at which these blades are disposed with respect to a plane normal to the axis of the cylinder-as shown at in FIGURE 2- is maintained at 22 plus or minus 3, and if the spacing between adjacent helical blades does not exceed 1.25 inches, the pull which a cutting cylinder fifty inches long exerts upon the side of leather being acted upon by the full length of the rapidly revolving cylinder, is no greater than that which in the past was exerted upon the side by a cutting cylinder less than 24 inches in length. Therefore, with the helical blades of the cutting cylinder disposed in accordance with this invention, a single operator can easily and successfully operate the shaving machine, despite the fact that its cutting cylinder and rolls are 50 long, which is long enough to accommodate a full width of a side of leather.

The minimum spacing between adjacent blades is limited by practical considerations, notably the fastening of the blades to the cylinder, and ordinarily cannot be less than one inch.

In operating the machine of this invention, the operator carefully spreads the leading portion of the side over the table 17 and then over the surface of the feed and backup roll 6, making sure that the projecting end portions, Whether they be shank or fore legs, are spread smoothly across the roll 6 before the blades of the cutting cylinder come into contact therewith. Then, as the side is drawn into the machine by the coacting cutting cylinder and feed roll, the operator watches that no portion of the side will be doubled up or folded and, in general, makes certain that proper feeding takes place.

Since the pull which the machine exerts upon the side of leather does not exceed the pull which the operator can himself exert upon the side, he can, of course, withdraw the same from the machine and restart the shaving operation if necessary. The important thing, however, is that at all times the operator has absolute control over the hide to thus assure satisfactory shaving, and further that because the cutting cylinder is long enough to accept the full width of a side, only two passes are required, whereas previously a minimum of four was necessary.

The criticality of the angle and spacing of the helical cutting blades set forth herein has been verified by actual use of machines made in accordance with this invention, by experienced shaving machine operators in actual commercial use.

What is claimed as our invention is:

1. In a leather shaving machine having a cutting cylinder with helical blades thereon pitched in opposite directions from the center of the cylinder towards the ends thereof, a backup member having a solid unyielding Work engaging surface to hold the portion of a side of leather being acted upon against the blades of the cutting cylinder, and means to rapidly revolve the cutting cylinder in the direction to draw a side of leather placed between the cylinder and the backup member into the machine and at the same time spread the side out towards the ends of the cylinder, the cylinder and the backup member being separable to allow a side of leather to be removed from the machine after the shaving operation, the improvement which enables the cutting cylinder to be long enough to accommodate the full width of a side and to act thereon without applying more tension upon the side than an operator can readily resist and control, and which improvement comprises the following critical angle and spacing of the blades and cutting cylinder:

(A) the angle which the blades form to a plane normal to the axis of the cylinder, is 22 plus or minus 3; and

(B) the spacing between adjacent blades does not exceed 1.25 inches, and is not greatly less than one inch.

2. In a leather shaving machine having a cutting cylinder with helical blades thereon pitched in opposite directions from the center of the cylinder towards the ends thereof, a combined backup and feed roll having a solid unyielding work contacting surface to hold the portion of a side of leather being acted upon against the blades and feed the same into the machine, and

means to revolve the cutting cylinder and backup and feed roll in opposite directions of rotation, with the backup and feed roll travelling at a periperal speed much slower than that of the cutting cylinder, and with the directions of rotation such that a side of leather gripped between the cylinder and backup and feed roll will be drawn into the machine, said machine being characterized by the following:

(A) The angle which the blades of the cutting cylinder form to a plane normal to its axis is 22 plus or minus 3; and

(B) the spacing between adjacent blades does not exceed 1.25 inches, and is not greatly less than one inch,

so that the pull exerted on the side of leather by the rapidly revolving cutting cylinder as the cylinder performs its shaving and spreading functions is not so great than an operator cannot easily control the entry of the side into the machine, despite the fact that the cutting cylinder and backup and feed rolls are long enough to accommodate the full width of a side of leather.

3. The leather shaving machine of claim 2, further characterized by the fact that the combined backup and feed roll has its surface roughened.

References Cited in the file of this patent UNITED STATES PATENTS 277,631 Taylor May 15, 1883 526,387 Evans Sept. 25, 1894 638,368 Wayland Dec. 5, 1899 999,540 Baker Aug. 1, 1911 1,183,758 OBrien May 16, 1916 1,410,703 Meyer Mar. 28, 1922 1,621,577 Blaney Mar. 22, 1927 1,863,777 Wayland June 21, 1932 2,570,470 Meyer et al Oct. 9, 1951 2,674,114 Brill et a1. Apr. 6, 1954

Claims

1. IN A LEATHER SHAVING MACHINE HAVING A CUTTING CYLINDER WITH HELICAL BLADES THEREON PITCHED IN OPPOSITE DIRECTIONS FROM THE CENTER OF THE CYLINDER TOWARDS THE ENDS THEREOF, A BACKUP MEMBER HAVING A SOLID UNYIELDING WORK ENGAGING SURFACE TO HOLD THE PORTION OF A SIDE OF LEATHER BEING "ACTED" UPON AGAINST THE BLADES OF THE CUTTING CYLINDER, AND MEANS TO RAPIDLY REVOLVE THE CUTTING CYLINDER IN THE DIRECTION TO DRAW A SIDE OF LEATHER PLACED BETWEEN THE CYLINDER AND THE BACKUP MEMBER INTO THE MACHINE AND AT THE SAME TIME SPREAD THE SIDE OUT TOWARDS THE ENDS OF THE CYLINDER, THE CYLINDER AND THE BACKUP MEMBER BEING SEPARABLE TO ALLOW A SIDE OF LEATHER TO BE REMOVED FROM THE MACHINE AFTER THE SHAVING OPERATION, THE IMPROVEMENT WHICH ENABLES THE CUTTING CYLINDER TO BE LONG ENOUGH TO ACCOMMODATE THE FULL WIDTH OF A SIDE AND TO ACT THEREON WITHOUT APPLYING MORE TENSION UPON THE SIDE THAN AN OPERATOR CAN READILY RESIST AND CONTROL, AND WHICH IMPROVEMENT COMPRISES THE FOLLOWING CRITICAL ANGLE AND SPACING OF THE BLADES AND CUTTING CYLINDER: (A) THE ANGLE WHICH THE BLADES FORM TO A PLANE NORMAL TO THE AXIS OF THE CYLINDER, IS 22* PLUS OR MINUS 3*; AND (B) THE SPACING BETWEEN ADJACENT BLADES DOES NOT EXCEED 1.25 INCHES, AND IS NOT GREATLY LESS THAN ONE INCH.