US3008704A - Multi-level flexible clamp for paper cutting machines - Google Patents

Description

c. THUMIM 3,008,704

MULTI-LEVEL FLEXIBLE CLAMP FOR PAPER CUTTING MACHINES Nov. 14, 1961 Filed Oct. 25, 1958 United States Patent C 7 3,008,704 MULTI-LEVEL FLEXIBLE CLAMP FOR PAPER CUTTING MACHINES Carl Thumim, Westbury, N.Y., assignor to The Lawson Company Division of Miehle-Goss-Dexter, Incorporated, New York, N.Y., a corporation of New York Filed Oct. 23, 1958, Ser. No. 769,256 7 Claims. (Cl. 269-203) This invention relates to flexible clamps for paper outters and more particularly to hydraulically powered clamps and the like.

In copending applications Serial No. 701,570 and Serial No. 755,161, filed by the present applicant and assigned to the same assignee, there is disclosed and claimed a paper cutter clamp having a plurality of individually movable clamping elements which are actuated individually by hydraulic means. The present invention relates to generally the same subject matter and constitutes an improvement and simplification of the structures shown in the applications referred to.

The primary object of the present invention is to providea clamping bar having a series of feet which co-act in groups so that each group of feet may be utilized to clamp a separate pile. Thus, a plurality of piles of differing height may be simultaneously severed.

In general, the objects of the prior inventions and of the present invention are otherwise substantially the same, v1z.,

The provision of a hydraulically operated clamp having a plurality of separate clamping elements carried thereby for engaging a paper pile in order to insure firm clamping at all points across the pile or piles.

It is another object of the invention to provide a clamp having a plurality of pressure operated units which engage the paper and wherein the pressure exerted by the units is controlled by the hydraulic pressure exerted on the clamp bar.

It is a further object of the invention to provide a paper clamp having a plurality of pressure applying units wherein such units are mounted so as to have a predetermined degree of play 'or rocking in order to conform to any irregularity along the line "of clamping of the paper pile.

It is a still further object of the invention to provide a clamp having a plurality of pressure units wherein said units are capable of independent action although having a common pressure supply.

It is yet a further object of the invention to provide a clamp having a plurality of individual pressure-powered 'clampingunits having a common pressure supply wherein the pressure of the supply varies with demand and may be controlled by the pressure of a separate supply which operates the clamp bar as disclosed in the afore-' mentioned copending application Serial No. 701,570.

It is an additional object of the invention to provide a clamp having a plurality of pressure operated units wherein the clamp construction is simple and rugged and requires a minimum of assembly and maintenance.

As is well known, the thickness of paper as it comes from the calendar rolls is not uniform across the width. Thus, if there is a'variation of .0001 inch, a'pile of a thousand sheets will provide an irregularity up to a tenth of an inch. This irregularity occursacross the clamping line'of the pile and 'it is therefore obvious that some parts of the pile along the clamping line will not be securely held; Thus, uneven cutting results.

Irregularity along the clamping line also occurs even with paper that is practically uniform in thickness, but which has been printed with heavy deposits of ink. The areas of heavy ink deposit are thicker than the unprinted areas; thus, uneven cutting again results.

It has heretofore been proposed to providea clamp 3,008,704 Patented Nov. 14, 1961 with a plurality of individually movable clamping feet which engage the paperv pile and compensate for height irregularities. However, such prior art devices are principally of a type which rely on a plurality of springs and it has been found that this expedient is not entirely satisfactory. I am also aware that clamps having a plurality of hydraulically operated presser feet have heretofore been known, but none of them have had the construction and the improvements afforded by the present invention and as set forth in the objects hereinabove, particularly wherein the present invention provides a flexible sole, so-called, which exerts a force along the clamping line that varies directly and automatically with the clamping force of the clamping bar.

Briefly, my invention comprises the provision of a plurality of individual feet carried at the bottom edge of a clamping bar, wherein such feet may be individually pressure-actuated in the direction of clamping, all as here tofore shown and described in the prior copending applications, but in this instance a plurality of feet are arranged in groups Wherein'the feet of each group are mechanically interlocked by a lost motion means so as to be restrained to a predetermined degree of relative motion with respect to each other. The purpose of such restraint is to safeguard against the breakage of a flexible sole strip which is bolted to the bottom of each group of feet and serves to provide a smooth, continuous surface for applying pressure to a paper pile by that group. Thus, such flexible sole pieces or strips which maybe of any suitable material such as Phosphor bronze, spring steel, or possibly even certain forms of plastic, such as nylon, are flexed by the feet, forcing the strip against portions of the pilevof differing height. Since it is desired that no portion of the strip be flexed more than a quarter of an inch beyond the plane of any other portion of the strip, the restraining means is necessitated to insure that the strip will not flex beyond such predetermined limit. Accordingly, all of the feet carried by the clamping bar are divided into groups; for example, four feet to a group and the bottom surfaces of the feet of each group have a flexible strip secured thereto and are individual to that group. Each group can move simultaneously with respect to the clamping bar, being coupled thereto by lost motion means affording a greater limit of movability. v

The restraining or motion-limiting means of the feet of any group consists of a pair of bars common to the feet of that group and disposed on opposite sides of the clamping bar extension which carries the feet. Thus, the bars are arranged intermediate the sides of the extension and the inner soles of the flanges which form the feet so as to co-act with grooves formed in the extension and in the flanges to limit motion of the feet with respect to each other.

A detailed description of the invention will now be given in conjunction with the appended drawing in which:

FIGURE 1 illustrates a front view of the clamping bar carrying a series of depending feet arranged in groups a, b, and 6.

FIGURE 2 is a section taken generally through 2-2 of FIGURE 1.

FIGURE 3 is an elevation of one of the restraining bars used as part of the invention.

FIGURE 4 is a plan'view of the restraining bar.

FIGURE 5 is a section taken generally through 5-5 of FIGURE 2.

FIGURE 6 is a fragmentary view of one external surface of the extension of the clamping bar showing the various grooves machined therein for coaction with certain elements to limit motion of the feet; and

FIGURE 7 is a fragmentary top plan view of the clamping bar with the cover removed.

Referring now to the drawing, a clamping bar is illustrated in which have been bored a series of pressure cylinders 14 for accommodating pressure pistons 18, all of which are fed by means of a groove or trough 22 machined ina cover plate 25, pressure fluid being provided via a pressure tube 28, all in a manner as heretofore described in the copending applications referred to hereinabove. The individual pistons 1-8 actuate rods 32 which extend downwardly and engage the bottom interior walls 35 of respectively pressure feet 38. It will be noted that the pressure feet are channel-like in section, having-a bottom portion 41 and side flanges 44.

The interior wall surfaces 47 of the flanges 44 have a sliding fit with a depending, narrowed body guide section 50 of the clamp bar 10, and will thus be understood to have relative motion with respect thereto upon pressure being applied to respective cylinders 14.

Each pressure foot is provided with a pair of parallel pins 53 carried at their ends in flanges 44 and which pins pass transversely through guide section 50 via respective elongated slots 56 machined therethrough.

From the foregoing description it will be apparent that the feet may move up and down with respect to 'FIGURES 1 and 2 to the limits provided by engagement of pins 53 with the upper and lower ends of the slots 56.

Thus, by providing a suitable length for the slots 56 it will be clear that the feet 38 may have a considerable relative travel with respect to each other. In fact, such relative travel is so great as to be beyond the safe flexure limits of flexible sole strips 60 which are individually applied to each group of feet, there being structure hereinafter described to limit undesirable travel.

As seen on FIGURE 1, a flexible sole strip is secured to each of the feet of the group a and another strip to the group b and a third strip to the group 0.

The strips may be fastened to the feet with which they co-act in any suitable manner, as set forth in the copending applications, for example, by bolts 63, or the like.

From the foregoing description it will be apparent that the feet have relative vertical motion with respect to the guide section 50 of the bar clamp as well as with respect to each other and that pressure exerted in the cylinders 14 will, acting through rods 32, force individual feet downwardly against the paper pile. However, it is necessary to effect clamping of piles such as x, y, and z, as shown in FIGURE 1, where such piles may vary considerably in height. Each group a, b, or c, is utilized for a particular pile and although, by virtue of the length of the slots 56, the feet of any one group can descend far enough to engage its respective pile, suitable means is provided to prevent the feet of any one group from moving relative to each other beyond a predetermined amount within the safe limits of flexure of the associated sole strip 60.

Thus, a lost motion means comprising apair of parallel bars 710 are carried within horizontally elongated grooves or transverse through channels 73 in opposed faces of the flanges 44 interiorally of certain feet, as seen on FIGURE '2 and referring to FIGURE l,'it will be noted that only the inner two feet of each of the groups a, b, c are provided with the tongues 76 and the grooves 80.

Each of the bars 70 is provided with repair of speed tongues 76 vertically slidable with an adequate amount of transverse looseness in respective grooves 80 machined into the outwardly facingwalls of guide section 50. The horizontally elongated grooves 73, which pass from edge to edge of the feet flanges 44, 'as seen on FIGURE 5, are of a height in excess of'the height of the bars '70 by the distance D as shown in FIGURE 2 It will now be apparent that the shoe 38 has vertical play with respect to the guide section 50 within the limits of the height of the grooves 80 which are commensurate with the height of the slots '56..

Accordingly, it will be apparent that a foot of any one group can have vertical play with respect to the other feet of that group only to the extent indicated by the distance D, or the order of A" for practical purposes, this being the distance between the vertical heights of the bars 70 and the grooves 73 in the inner faces of thefeet flanges. However, all of the feet'of each group may move simultaneously within the limits of the distance S, as shown in FIGURE 2, with respect to the guide section 50, the distance S being understood to be the difference between the height of the tongues 76 and the grooves 80.

Thus, the greater limits of motion afforded by the lost motion corresponding to distance S compensates for large differences in heights of various piles, while the lesser limits of motion afforded by the lost motion corresponding to the distance D compensates for varying thickness of any individual pile. The distance D is, of course, predetermined in accordance with the safe degree of flexure permissible for the strips 60, about A inch.

There must, of course, be a correlation between the length of the slots 56 and the length of the grooves 80. In other words, the slots 56 must be of suflicient length to permit full travel of the tongues 76 from top to bottom of respective grooves 80. Such dimensioning 1s, of course, a matter of design, being generally equal to the distance S+D.

While the guide bars 70 could perform their dual lost motion function as well as the function of slots 56 and pins 53, thus eliminating the pins and slots, prefer to use the pins and slots to stabilize the coupling of the feet with the clamping bar.

I am aware that various changes may be made without departing from the spirit of the invention and, accordingly, I do not seek to be limited to the precise illustration herein given except as set forth in the appending claims.

I claim:

1. In a clamp for simultaneously clamping separate piles of paper of varying height; a clamp bar having a plurality of groups of presser feet, said plurahty of groups of presser feet operatively connected to said clamp bar, and means operatively positioned with respect t o said groups and said bar whereby the groups are indivldually movable with respect to each other within predetermined limits and means engaging said feet whereby the feet of each group are individually movable with respect to each other within lesser predetermined limits.

2. A device as set forth in claim 1, including a respective flexible sole strip secured to the feet of each group and common to that group and having a limit of flexibility within the lesser predetermined limits of movability of said feet.

3. A device as set forth in claim 1, wherein the means for effecting both of said predetermined limits comprises a respective bar element common to the feet of each group and the feet of each group having spaced abutments engageable with said bar element in either direction of travel, wherein the spacing between abutments is greater than the dimension of said bar element in the direction of travel to effect a lost motion coupling and wherein the degree of lost motion thereof determines the lesser predetermined limits of travel of the feet of each group, and lost motion means whereby said bar element is coupled to said clamp bar so as to have relative movability with respect thereto affording a relatively greater degree of lost motion for each group of feet.

4. A device as set forth in claim 1, each of said movement limiting means comprising a motion limiting element having lost motion coupling with each group of feet and having lost motion coupling with said clamp bar, the degree of lost motion of the latter coupling being the greater.

5. In a clamp for simultaneously clamping separate piles of paper of varying height; a clamp rb h i a plurality of groups or presser feet operatively connected thereto, and means whereby the groups are individually movable with respect to each other within predetermined limits and means whereby the feet of each group are individually movable with respect to each other within lesser predetermined limits, each of said movement limiting means comprising a motion limiting element having lost motion coupling with each group of feet and having lost motion coupling with said clamp bar, the degree of lost motion of the latter coupling being the greater, and a respective flexible sole strip for the feet of each group.

6. In a. device as set forth in claim 5, including means effective to individually actuate said 'feet for providing clamping pressure.

7. In a device of the class described; a clamp bar having a guide section 50 effecting a pair of parallel side surfaces provided with respective grooves 80, respective bars 70 having respective tongue means 76 protruding into respective grooves 80 on each side odz said guide section 50 and having vertical lost motion movement therein, a group of presser feet operatively connected to said clamp bar, each comprising parallel flanges 44 having horizontally transverse through channels 73, said channels 73 being generally horizontally aligned in plurality on each side of said guide section, each bar protrudin-g into a respective plurality of aligned channels 73 on a respective side of said guide section, and having a vertical 10st motion movement within said channels to a lesser degree than said aforementioned lost motion movement.

References Cited in the file of this patent UNITED STATES PATENTS 2,105,402 Brownlee Jan. 11, 1938 2,446,852 Sai-ler Aug. 10, 1948 2,600,127 Reaser et a1 June 10, 1952 2,692,633 Green Oct. 26, 1954 2,815,051 Spanhel et a1. Dec. 3, 1957

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