US1729582A - Cutter clamp - Google Patents

Description

E. R. KAST CUTTER CLAMP Sept. 24, 1929.

Filed July 6,

1926 2 Sheets-Sheet l ,T .m r

PAPA- P/LF NVENTOR BYM. cwu

'T ATTORNEYS iii-*- Sept. 24, -1929. l E, R, KAST 1,729,582

CUTTER CLAMP Filed July 6, 1926 2 Sheets-Sheet 2 Ime/non if ad? Patented Sept. 24, 1929 UNITED STATES PATENT OFFICE EDWARD R. KAST, OF PEARL RIVER, NEW YORK, ASSIGNOR TO DEXTER FOLDER COM- PANY, OF NEW YORK, N. Y., .A CORPORATON OF NEW YORK CUTTER CLAMP Application filed July 6, 1926.

' sired size.

It has heretofore been proposed, when cutting a pile of paper supported on a table or the like, to clamp the paper with a straight clamp, 'the clamping surface of which is parallel with the table. Clamps such as these, however, have certain defects and disadvantages, in that there is a tendency for the sheets of paper to slide out horizontally between the clamp and the table when engaged by the knife. This is particularly true with certain grades of paper having hard surfaces, and in the event the pile of paper consists of printing or design work, it frequently happens thatthe sheets are severed across the printing or design work, producing what is techically known as bleeding the printed work and thereby ruining the sheets with the resulting loss in material and labor to the printer.

The objects of this invention are to provide paper clamping means which avoid the difficulties and disadvantages above referred to; which may be readily embodied in existing paper cutting machines without material alteration in the construction thereof; and by the use of which the normal massive construction of the clampino elements may be lightened.

This invention will be better understood by reference to the accompanying drawing which illustrates several embodiments of the inventive idea and wherein Fig. 1 is a detail perspective view of a paper cutting machine equipped with a clamp embodying the present invention, parts of the machine being broken away for purposes of clearer illustration;

Fig. 2 is a vertical sectional view on the line 2-2 of Fig. 1;

Fig. 3 is an end view of the clamp, showing diagrammatically the straight cut obtained thereby and the inclined cut obtained by existing equipment;

Fig. 4 is a vertical sectional view illustrat- Serial No. 120,790.

ing diagrammatically the effect produced by a straight bottom clamp on the pile of paper, prior to engagement of the knife therewith;

Fig. 5 is a view similar to Fig. 4f, showing the effect produced on the pile of paper by engagement of a straight bottom clamp and the knife;

Fig. 6 is a vertical sectional view illustrating diagrammatically the effect produced on the pile of paper by engagement of the clamp of the present invention therewith;

'Fig Z is a vertical sectional view showing another embodiment of the invention; and

Fig. 8 is a vertical sectional view showing another embodiment of the invention.

Referring to the drawings, wherein like reference numerals designate like parts throughout the several views, 5 indicates a portion of the main framework of one type of machine on which the invention may be used and on which the cross head 6, carrying the cutter blade 7, is mounted to reciprocate vertically and transversely of the machine in the usual manner (Fig. 1). The knife operating` shaft, indicated at 8, is suitably journaled on the machine framework and provided on the projecting end thereof with cranks, one of which is indicated at 9. The cranks are connected, by means of links 10, 10 with the opposite end of the cross head 6 so that when the knife operating shaft 8 is rotated the links 10, 10 will cause the cross head and cutter blade to reciprocate vertically and transversely of the machine. The shaft 8 is driven by the large gear 11, rigidly secured to one end of the shaft, and meshing with a clutch controlled driving pinion 12 which is mounted on the main power shaft of the machine (not shown). The table or support 13 for the pile of paper 14 is mounted on the machine framework in the usual manner and carries a back gauge 15 controlled from the front of the machine by a band or cable 16 which passes around pulleys mounted on the underside of the cable and one of which is indicated at17. The paper holding clamping bar or plate, indicated at 18, is provided at its end with downwardly extending guide bars 19, 19 whereby the clamping bar or plate is slidably mounted on the machine framesol work for vertical reciprocating motion. The clamping bar or plate 18 carries the usual weight bar 2O which is reciprocated with the clamp 18 as the latter is raised and lowered to engage or disengage the pile of paper 14 on the table 13. The lower ends of the guide bars 19, 19 have secured thereto in any desired manner the ends of chains 21, 21 which pass over pulleys or sheaves 22, 22 journaled in any suitable manner on the machine framework. The opposite ends of the chains 21, 21 are connected with rods 23, 23 anchored as at 24, 24 to the ends of a. counterweight 25 for balancing the weight of the clamp 18 and parts carried thereby. The ends of thev counterweight 25 are pivotally connected as at 26, 26 with arms 27, 27 fixed on shaft 28 journaled in suitable bearings 29, 29 on the machine framework The shaft 28 has fixed thereon a bell crank, one arm 30 of which carries a foot piece 31, the arm 32 of said bell crank extending` within a slot 33 formed in the underside of the counterweight 25.

The guides 19, 19 are provided at the bottom thereof with rack blocks 34, 34 which mesh with segmental gears 35, 35 fixed on a driven shaft 36, each end of which is journaled in a bracket 37 secured to the machine framework. The shaft 36 carries at one end a friction wheel 38 engaged by a slip clutch 39 connected with an arm 40 loosely mounted on the driven shaft 36. The arm 40 is connected with one end of a pitman 41, the opposite end of which is connected with a crank 42 fixed on one end of a shaft 43 journaled in described, actuates the rack blocks 34, 34 on the guides 19, 19, the arm 32 thereafter ele- Vati-ng the co-unterweight 25 so that the paper clamping bar or plate 18 descends and engages the pile of paper 14 as shown in Fig. 2. When pressure is removed from the foot plate 31, the parts illustrated in full lines in Fig. 1 return to the position there shown. The pinion 12 when clutched to the power shaft by the usual control means, causes the gearing described above to move the bar 18 into clamping engagement with the pile 14, the clutch 39 and friction wheel 38 serving to control the application of the necessary pressure on the pile 14 by the bar or clamp 18. At the same time, the knife operating shaft 8 causes the 'knife 7 to move downwardlyand transversely of the machine so as to cut the pile of paper 14 clamped on the table 13. These operations take place during onehalf of the revolution of the knife operating shaft 8, the succeeding half revolution of said shaft causing the paper clamping bar or plate 18, the cross head 6, and the knife 7, to be lifted to the position shown in Fig. 1.

Referring now to Figs. 4 and 5, it will be noted that when a straight bottom clamp such as indicated at A, firstengages the pile of paper, it compresses the pile to a certain extent, thus bending portions of the sheets in the slanting positions indicated by the lines R-R and S-S with resulting forces which counteract each other so that no endwise movement of the sheets between the clamp and the table occurs. The motion of the knife B, however, is so timed that it engages the pile immediately after the clamp, thus building up additional pressure on the pile and further compressing the same before the knife cuts through the pile. As shown in ig. 5, this additional pressure bends por.- tions of the pile of sheets in positions shown by the lines T-T and U-U. The normal reaction from the combined pressure of the knife and clamp is indicated at N and the pressure on the table is indicated at V, leaving an unbalanced force H. The paper being confined by the clamp and table, this unbalanced force H tends to slide the sheets horizontally so that when the sheets are unclamped, it is generally found that they have not been cut accurately. This difficulty is of long standing and has characterized all the standard types of cutters with which I am acquainted. Efforts to avoid such angular cuts have usually been directed along the line 1of applying more pressure `onthe .clamp and change in the shape of the cutting knife, but this has proved unavailing. However great the pressure applied, the angular cut will still be made and this has evidently been caused, as above indicated, by the additional pressure applied to the pile of sheets by the cutting knife.

I have discovered that a straight cut normal to the paper support, such as indicated by the full arrow in 3, can kbe produced through the pile of paper 14 by progressively increasing the pressure applied by the clamp from its front edge to its rear edge. This may be accomplished by providing the clamping bar or plate 18 with a paper engaging surface 44 gradually inclined or curved upf wardly from the rear edge of the clam to the front edge of the same. When a clamp thus constructed is lowered intov engagement with a pile of paper, the pressure on the pile exerted by the clamp progressively decreases from the rear edge of said cla-mp to the front edge thereof or progressively increases from the knife and the front edge of the clamp to the rear edge of the latter. This is demonstrated by reference to Fig. 2 wherein it will be noted that the lportion of the pile 14 disposed under the surface 44 progressively increases in height from the rear edge of the lll clamp towards its front edge and toward the knife.

With a clamp such as last described, the pile 14 is so held that the additional pressure of the knife 7 when it engages the pile will not displace the sheets as heretofore, and a shear cut absolutely normal to the clamp is secured. The progressively increasing pressure of the present clamp on the pile rearwardly of the knife, or as otherwise expressed, the progressively decreasing pressure of said clamp on the pile from the rear edge of the clamp toward the knife, counteracts the displacing tendency of the knife, the inclined surface 44 of the clamp engaging the pile, acting as a wedge to prevent horizontal displacement of the sheets between the clamp and the table. This is demonstrated diagrammatically with the embodiment of the invention shown in Fig. 6, where the normal resistance to the clamp face is indicated at N and the vertical reaction on the table is indicated at V. In this instance, however, the horizontal component I-I tends to push the paper in a direction opposite to the force H of Fig. 2, so that a wedging effect is produced by the inclined bottom of the clamp which, as above stated, counteracts the tendency of the sheets to slip horizontally between the clamp and the table by the additional pressure of the knife on the ile.

p The embodiment of the invention shown in Fig. 7 is substantially the same in construction and operation as that illustrated in Figs. 2, 8 and 6, except that in the present instance the rear edge of the clamp 18 is curved as at 18 so that a sharp edge that might mar the stock is avoided.

In the embodiment shown in Fig. 8, the effect produced by cutting through the clamped paper is the same as results from the employment of clamps such as illustrated in Figs. 2, 3, 6 and 7. In this instance, however, a straight bottom clamp A, such as illustrated in Figs. 4 and 5, is employed, but the table or support has an inclined angular clamping and supporting surface 13 for the pile of paper, so that when the knife B engages and passes through the pile of paper, it will make a straight cut therethrough instead of the angular cut resulting when a straight bottom clamp and a pile supportparallel therewith are employed, the pressure on a pile of paper clamped between the surface 13 and the bottom of the clamp A, progressively decreasing from the rear edge to the front edge of said clamp Ior progressively increasing from the knife B and the front edge of the clamp to the rear edge of the latter.

With this construction of clamp plate it is' possible to largely reduce the massive construction of the pressure devices heretofore employed and to largely reduce the clamping pressure heretofore applied, while at the same time securing results with respect to accuracy of cut that it has heretofore been impossible to secure. The clamp plates or pile Supports of all makes of cutters such as the Dexter, Sibold, Sheridan and Chandler and Price can be readily changed to embody this invention, thus correcting simply and economically a difculty that has long troubled the art.

While the degree of bevel of the face of the clamp plate may be varied for different sizes of cutters and clamp plates and different varieties of stock to be cut, I have found that a bevel of 1/32 on aclamp plate 4 wide gives entirely satisfactory results, though obviously I do not limit myself to these particular proportions, as the invention consists broadly in inclining or b'eveling the clamp face to secure the desired results.

What is claimed is:

1. The combination with a knife and means for supporting a pile of paper, of a clamp for engaging the pile of paper while the same is being cut and adapted to apply successively decreasing pressure on the pile from one side of the clamp to said knife.

2. The combination with a knife and means for supporting a pile of paper, of a clamp for holding the pile on said means while the paper is being cut, said clamp having a paper engaging surface inclined upwardly to the knife so as to apply successively decreasing pressure on said pile from the clamp to said knife.

3. The combination with a knife and a support for the paper to be cut, of a clamp for holding the paper on its support while being cut, said clamp having a paper engaging surface gradually increasing in height with respect to the support, from the side of the clamp remote from said knife.

4. The combination with a knife, of a clamp and a support between which paper is clamped to be cut by the knife, one of said lastnamed elements being adapted to engage the paper so that the clamping pressure thereon gradually decreases to the knife.

5. The method of clamping a pile of paper to be cut, which consists in applying gradually decreasing pressure on the pile from a point at one side of the line of cut to said line.

In testimony whereof I have signed this specification.

EDWARD R. KAST.

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