US3025049A - Flexible clamp for paper cutters - Google Patents

Description

March 13, 1962 c. THUMIM FLEXIBLE CLAMP FOR PAPER CUTTERS 2 Sheets-Sheet l Filed Dec. 9, 1957 lll/1L INVENTOR. CH/L r//aM//W BY ,Z 4

/s/WM fr rae Me' Vr I March 13, 1962 c. THUMIM FLEXIBLE CLAMP FOR PAPER CUTTERS 2 Sheets-Sheet 2 Filed Dec. 9, 1957 aired y3,i25,@49 Patented Mar. 13, 1962 3,625,049 FLEXIBLE CLAMP FR PAPER CUTTERS Cari Thumim, Westbury, NX., assigner to The Lawson Company Division of Miehle-Goss-Dexter, Inc., New York, NX., a corporation of New Yori:

Filed Bec. 9, 1957, Ser. No. 74H57() 9 Claims. (Cl. 269-153) This invention relates to tlexible clamps `for paper cutters and more particularly to hydraulically powered clamps.

It is an object of the invention to provide a hydraulically operated clamp having a plurality of separate clamping elements carried thereby for engaging `a paper pile inlorder to insure firm clamping at all points across lthe p1 e.

It is another object of the invention lto 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 deUree 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.

lt is yet a further object of the invention to provide a clamp having a plurality of individual pressure-powered clamping units having a common pressure supply Whereing the pressure of the supply varies with demand and may be controlled by the pressure of a separate supply which operates the clamp bar.

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

As is well known, the thickness of paper as it comes from the calender 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 occurs across 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.

lt has heretofore been proposed to provide a clamp with a plurality of individually movable clamping feet which engage the paper 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 yfeet 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.

Briey, my invention comprises the combination of a hydraulically operated clamping ybar which may be mounted and translatable by conventional construction and which clamping bar carries a plurality of lluid (gaseous or liquid) operated pressure feet wherein the uid pressure, from a common source, exerted on pistons which actuate the individual feet varies in accordance with the hydraulic pressure utilized by the bar. In one form a pressure control valve may be incorporated in the oil line of the hydraulic clamp to be actuated by the pressure in that line so as to control `the fluid pressure which goes through the valve to feed the plurality of individually movable presser elements.

The construction of the invention contemplates a clamping bar having a plurality of bores in which are disposed tluid operated pistons for actuating rods of respective pressure shoes. The pistons are disposed in aligned chambers across the length of the clamping bar in such a way as to simplify feeding of uid pressure thereto. A ilexib-le strip or sole plate of properly conditioned material extends the operative length of the clamp bar and is secured to each of the pressure shoes so as to form a smooth and continuous surface for engagement with a paper pile. Due to the ilexibility of the metal strip, the contour of the pile may be accurately followed whilst uniform pressure is applied thereto all along its length by the plurality of pressure shoes.

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

FIGURE l is a fragmentary elevation of a portion of the novel clamp.

FIGURE 2 is a plan of the fragmentary elevation.

FIGURE 3 is a section through 3-3 of FIGURE 2.

FGURE 4 is an elevation, to reduced scale, showing the entire clamping bar casting.

FlGURE 5 is a plan view of the entire clamping bar casting.

FIGURE 6 is a cross-section showing the control valve whereby hydraulic pressure which operates the clamping bar serves to control the pneumatic pressure of a common feed for the plurality of pressure elements; and

FIGURE 7 is a block diagram showing the relationship of the oil and air pressure systems in conjunction with the control valve which controls air pressure to the individual presser elements in proportion to oil pressure in the clamp bar actuating mechanism.

Referring now to the drawing and in particular to FIG- URES 1, 2 and 3, the invention comprises a clamp bar 1t) comprising a casting 12 (shown in full length in FIG- URES 4 and 5) having a plurality of aligned bores 15 open at the top for receiving respective cylinder sleeves Ztl. The sleeves are oriented so that a pair of diametrically opposed slots, such as 24, at the upper end of each sleeve are all aligned for the length of the casting. The slots 24 (FIGURE 2) align with slots 27 formed in the casting between the bores 15. Thus, a manifold comprising slots 24 and 27 is effected for common pneumatic feed to the cylinders.

The tops of the cylinders `are closed by a cover plate 30 which extends the length of the casting and is secured as by bolts 33.

At the bottom of each bore l5 is an opening provided with a bushing 36 in which reciprocates a push rod 40 that abuts the lower face of a piston 43 of respective cylinders. A light spring 46 is utilized to maintain downward bias on the piston for engagement with the push rod, in each instance.

The lower part of the casting is formed with a guide portion 50 of generally rectangular configuration and extending substantially Ithe length of the casting, which guide portion is provided with a plurality of bores, such as S3, being aligned axially with respective cylinders. Each bore 53 is provided with a bushing 57 in which the lower end of the respective push rod 40 reciprocates.

Smoothly machined outer faces 60 and 62 of the guide portion 56 slidably engage a series of aligned presser elements 65 which will be seen to be of generally U shape, having legs joined by an intermediate bottom section, so as to enclose a respective portion of guide 56 and be vertically reciprocal with respect thereto. Each push rod 4G abuts the internal bottom surface of the U profile within a respective presser element 65 as shown clearly in FIGURE V3.

In order to retain the elements 65 on the casting a pair of vertically staggered bores such as 68 and '76 is provided on opposite sides of each push rod and a pair of bolts, such as 73, extend through the legs of the U-shaped presser element, one on each side of the pusher rod. The diameter of the bores 70 is approximately one quarter of an inch larger than the diameter of the bolts 73 so that each presser element 65 is allowed a certain amount of free play for rocking or vertical or horizontal movement with -respect to adjoining presser elements. It will be noted from FIGURE l that the upper sides of the presser elements are tapered, as at 76, in order to provide clearance for rocking in either direction of the presser elements, or for sidewise movement and the lower corners rounded to limit the stress concentration on the flexible sole plate.

The bottom surfaces of the presser elements are covered by an elongated flexible strip or plate 7S, bolted as by a bolt 7%, to each element, and it will thus be understood that the plate 7S forms a continuous ilexible surface for clamping abutment with a paper pile.

From the foregoing description it will be apparent that fluid pressure in the chambers will force down respective pistons and push rods, thus exerting a downward thrust on respective pressure elements 65, serving to clamp a paper pile at a plurality of points, and that irregularities in the paper pile will cause llexure of the plate '73 to thereby completely bind the pile along the clamping line, regardless of irregularity of height therealong.

As heretofore stated, the clamp is hydraulically operated as by oil pumped under pressure to suitable pistons and cylinders which eifect upward or downward motion of the casting 12 all in a manner heretofore known and, accordingly, no details of the hydraulic system or method for the casting is needed herein. Reference may be made to prior art patents showing such construction as follows: Patent Nos. 2,506,651, 2,574,501, 2,638,166 and 2,649,- 910.

'I'he alignment of slots 27 terminates in an inlet port 83 at one end of the casting whereby a common feed from a source of air pressure may be provided throughout lthe length of the casting to all cylinders via respective slots 24. The lower end of each bore is equipped with a leakage port to eliminate back pressure on the piston.

Referring now to FIGURES 6 and 7, a pressure control valve 911 is disclosed having a piston 93 in a cylinder chamber 96 which will now be understood to be connected to the pressure side of the clamp actuating hydraulic systern through the bore 98. Within the valve housing is a diaphragm 99 backed by a plate 12 which is engageable by a rod 165 upon downward pressure being exerted on piston 93 by oil in the clamp system, thus serving to close off a valve seat 110 by means of a valve head 113 which is secured through the diaphragm to the plate 102. The valve head 113 is rigidly connected through a stem 116 to a valve head 120 which will be understood to be engageable with a valve seat 123 to close ott the valve seat 110, stem 116 threading into plate 102 to secure the diaphragm thereto.

An inlet 127 is provided for fluid under pressure as from a pump and an outlet 130 is provided for fluid to feed to the aligned slots 15 and 27 of the casting through the port 83 indicated in FIGURE 5. Intermediate the spaced valve seats 110 and 123 is a bore 133 and it will be apparent from FIGURE 6 that when seat 110 is closed fluid pressure can pass from inlet 1'27 through port 133 and thence to outlet 113i). Thus under conditions wherein oil pressure is maintained in the chamber 96, valve seat is closed off and lluid is fed to the manifold port S3 and thence to the plurality of cylinders 15 for actuation of the presser elements. However, as the oil pressure diminishes in chamber 96, fluid pressure in the line to the presser elements effects upward thrust on the diaphragm 99 which forces closure of seat 123 by valve head 126, whence iluid to the presser elements is cut off, it being understood that the area of diaphragm 99 is considerably in excess of the area of valve head so that the diaphragm is controlling. Further, the area of piston 93 is so related to the area of diaphragm 99 that with full hydraulic pressure in chamber 96 there will be just enough outlet air pressure to provide a balance so that valve seat 110 is closed. Accordingly, as hydraulic pressure 96 is reduced, when the clamp is being released, pressure existing in the outlet will be suflicient to ultimately overcome the downward force of piston 93 whence the piston will be forced upwardly by the iluid pressure on diaphragm 99 to close off air pressure at valve seat 123.

From the foregoing description it will be apparent that the valve 9@ is capable of increasing fluid pressure to the presser element cylinders as oil pressure in cylinder 96 increases, and vice versa. Accordingly, effective control of individual presser element forces is maintained in accordance with operator control of hydraulic `system pressure. Actually, in operating the machine the operator does nothing more than adjust the clamp pressure in the normal way to obtain the best cutting results. Fluid pressure control is then automatically obtained.

Where the automatic control is considered too expensive, a reducing valve is supplied for the operator to ladjust the fluid pressure as required to obtain flexibility.

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

I claim:

1. A clamp bar mechanism comprising a clamp bar having a depending guide portion extending downwardly therefrom, said portion extending substantially the length of said clamp bar; and a plurality of individual presser elements of generally U-shape engaging said portion, said presser elements having legs straddling said guide portion, including a plurality of respective bores through said guide portion, a pusher rod through each bore and respective pressure actuating means carried by said bar for actuating respective pusher rods, each pusher rod being disposed for engagement with an intermediate portion of respective presser elements disposed between the legs thereof.

2. A clamp bar mechanism comprising a clamp bar having a depending guide portion extending downwardly therefrom, said portion extending substantially the length of said clamp bar; and `a plurality of individual presser elements of generally U-shape engaging said portion, said presser elements having legs straddling said guide portion, including means for loosely securing said presser elements to said guide portion, a flexible sole plate carried below said presser elements and engageable thereby to effect continuity of clamping engagement, said presser elements having adjacent tapered side edges to permit rocking thereof in a plane parallel to the plane of said guide portion, -and said presser elements having lower corners rounded to reduce stress concentration on the flexible sole plate.

3. A clamp bar mechanism comprising a clamp bar having a depending guide portion extending downwardly therefrom and provided with machined surfaces on opposite sides thereof, said portion extending substantially the length of said clamp bar; and a plurality of presser feet of generally U-shape engaging said portion, said presser feet having legs with machined interior surfaces engaging the respective machined surfaces of said guide portion; including a plurality of bores through said `guide portion; a pusher rod through each bore and respective pressure actuating means carried by said bar for actuating respective pusher rods, each pusher rod being disposed for engagement with `an intermediate portion of respective presser feet disposed between the legs thereof.

4. In a mechanism as set forth in claim 3, and means for loosely securing said presser feet to said guide portion, said means comprising a pair of bores passing through said guide portion on each side of the respective pusher rod and a pair of bores through the legs of the respective presser feet and alignable with the respective bores through said Aguide portion; a respective bolt means passing through aligned bores of said guide portion and presser feet; the bores in said guide portion being larger than the diameter of the bolts passing therethrough to provide play for the respective presser feet.

5. In la paper cutting machine, a fluid pressure actuated clamp bar, a clamp bar pressure feed means for actuating said clamp bar, a plurality of fluid pressure actuated presser elements carried by said clamp bar, a second pressure feed means common to all of said presser elements for actuating said presser elements, a control valve, both of said pressure feed means communicating with said control valve, said valve having means to open and close iow of fluid from said presser element pressure feed means to said presser elements responsive to degree of pressure of fluid in said clamp bar pressure feed means.

6. In a paper cutting machine as set forth in claim 5, said valve means comprising a piston chamber connected to said clamp bar pressure feed means, a valve chamber connected to said presser element pressure feed means, said valve chamber being closed by a diaphragm; `a valve head movable with said diaphragm; a piston in said piston chamber disposed to effect force in one direction on said diaphragm; a valve seat closable by said valve head in response to movement by said piston when clamp bar fluid pressure is above a predetermined limit, and wherein said valve seat is openable by fluid pressure feeding said presser elements and acting against said diaphragm when pressure diminishes in said piston chamber below said predetermined limit.

7. In a paper cutting machine as set forth in claim 5, said valve means comprising inlet and outlet ports for ow therethrough of tluid from said presser element pressure feed means to said presser elements; a partition separating said ports, a passage through said partition, each end of said passage terminating in a valve seat; a pair of alternately seatable valve heads coacting with respective seats, a bore through said partition communicating said outlet port with said inlet port via said passageway when said valve heads are positioned so that one of said valve heads is open relative to its seat and the other is closed relative to its seat; said valve means also comprising an actuator device for effecting said latter position when the Huid pressure feeding said clamp bar is greater than the uid pressure feeding said presser elements.

8. In a paper cutting machine as set forth in claim 7, said actuator device comprising a fluid pressure actuated element connected to said valve heads and exposed to fluid pressure in said outlet port and being actuatable by said outlet port fluid pressure to close said passage relative to said inlet port when iluid pressure in said outlet port is greater than clamp `bar Huid pressure so as to cut off feed of fluid pressure to said presser elements.

9. in a paper cutting machine, a iluid pressure actuated clamp bar, a clamp bar pressure feed means for actuating said clamp bar, a plurality of fluid pressure actuated presser elements carried by said clamp bar, a presser element pressure feed means common to all or" said presser elements for actuating said presser elements, a control valve, both of said pressure feed means communicating with said control valve, said valve having means communicating with said control valve, said valve having means to open and close flow or" uid from said presser element pressure feed means to said presser elements responsive to degree of pressure of uid in. said clamp bar pressure feed means, said clamp bar pressure feed means utilizing a liquid medium and said presser element pressure feed means utilizing a gaseous medium.

References Cited in the file of this patent UNITED STATES PATENTS 911,337 Seybold Feb. 2, 1909 980,241 Gardner et al. Ian. 3, 1911 1,404,239 Seybold Jan. 24, 1922 1,881,185 Hazelton Oct. 4, 1932 2,105,402 Brownlee Jan. 11, 1938 2,269,328 Williamson Jan. 6, 1942 2,314,645 Duda Mar. 23, 1943 2,600,127 Reaser et al June 10, 1952 2,699,649 Messick Jan. 18, 1955 2,781,844 Pearson et a1. Feb. 19, 1957

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