US2836415A - Feed rolls for bag making and like machines - Google Patents

Description

May 27, 1958 H. A. RoHDlN FEED RoLLs EOE BAG MAKING AND LIKE MACHINES Filed April 6, 1955 2 Sheets-Sheet 1 BY PM@ ATTORNEY May 27, 1958 H. A. RoHDlN FEED ROLLS FoRBAG MAKING AND LIKE MACHINES Filed April 6. 1955 2 Sheets-Sheet 2 A ORNEY United States Patent() FEED ROLLS FOR BAG MAKING AND LIKE MACHINES Howard Arrid Rohdin, Glen Ridge, N. J.

Application April 6, 1955, Serial N0. 499,674

6 Claims. (Cl. 27h-2K3) It is an object of this invention to provide a pair of feed rolls for webs of paper or the like which, though of extreme length, may yet be made of minimum diameter.

It is a further object of this invention to provide feed rolls as aforesaid, with a mounting such as to assure uniform pressure along the entire length of the rolls.

The above and other objects will be made clear from the following detailed description, taken in connection with the annexed drawings, in which:

Fig. l is a front elevation, partly in section, of a pair of my improved feed rolls; Y

Fig. 2 is a section taken on the line 2-2 of Fig. l; and

Fig. 3 is a top plan view of the left hand end of the unit.

In bag machines, feedrolls are essential to draw the web or webs into tubular relationship. Such rolls usually operate on the web or webs after the same have been brought into tubular relationship. Since obviously the rolls must act on the webs by frictional rather than positive engagement, the rolls must exert considerable pressure on each other. As the width of the web increases, it has heretofore been considered necessary to increase the diameter of the rolls, in order to provide sucient rigidity to withstand an increased load distributed over a greater length. For the purposes of mechanical analysis, each roll may be considered as a beam, supported at the ends and of uniform loading. Since in such case, the maximum moment varies as the square of the length, and since the stiffness of the beam depends on its depth or diameter, it is clear that ordinary engineering principles would require that the diameter of the roll be materially increased to balance out the increased moment, occasioned by an increase in length. This increase in diameter, however, directly increases not only the cost of the roll but the overall length of the bag machine. The present invention permits the exertion of uniform pressure between small diameter rolls regardless of length.

The machine is made up of side frame members 10 and 12, supported by end frame members 14. A framing member 16 supports, in a journal 18, an upper shaft 20 and in a roller bearing 22, a lower shaft 24. A stud 26 penetrates the journal 18 and is secured thereto by a pin 28. A collar 30 is attached to the upper end of the stud 26 and bears against a spring 32, which in turn bears against the upper portion of the frame member 16 and thus tends to lift the shaft 20 away from the shaft 24. n the upper shaft 2t) are mounted a plurality of feed rolls 34, each comprising a hard inner core 36 and a softer outer layer 3S of some frictional material such as rubber, or the like. In each roll 34 the core 35 and the surface layer 3S are bonded together, as for example, by vulcanizing. Each core 36 is keyed to the shaft 2i) by a pin 40.

Between each of the rolls 34 are transverse members 42, which surround the shaft 20 and each of which has a roller bearing 44 between it and the shaft.

One end of each of the members 42 has a pointed Y 2,836,415 Patented May 27, 1958 arm 46, the point of which has fulcrum-like engagement with the side frame member 12. At the opposite end of each member 42 is an arm 48, covered by a wear plate 50. At the lower end of the side frame member 10, is attached an angle iron 52, which faces the wearplates 50. Between the angle iron 52 and the plates 50, is a flexible length of hose 54.

The lower shaft 24 has mounted thereon a series of rolls 56, substantially identical in construction and mounting with the rolls 34 on the upper shaft 20. These are supported by transverse members 58, which are rigidly fixed to side frame members 60. It will be noted that each top roll 34 equally overlies portions of each of a pair of bottom rolls 56. Such registry is made possible by supplying at each end of the upper shaft 20, a shortend top roll 62.. On one of the rolls shown in Fig. 3 is shown a localized operating member 100. This may be a printing plate, a die cutter or any other desired tool, and may be placed on any of the rolls. The fulcrums 46 and the hose 54 permits localized relief of any such tool-bearing roll without distortion of either of shafts 2i) or 24 at the end bearings.

While the draw, which must be exerted by the rolls, is fairly heavy even at constant speed, it is exceptionally heavy in intermittent operation, as for example, in a bag machine operating on heat sealing principles where there must be substantial dwell to permit perfection of the heat seals. This is particularly true of barrier type, heat-sealable laminations. In such case, the machine can be speeded up only by increasing the acceleration of the feed rolls, since the sealing time is fixed by the requirements of the material. Such increased acceleration vastly increases the friction requirements between rolls, which means that the pressure between the rolls must be enormously increased. This is accomplished in the present machine by supplying either pneumatic or hydraulic pressure to the interior of the hose 54, which tends, on the application of such pressure, to expand between the surfaces 50 and 52, thereby tending to rock the members 42 downwardly about their fulcrums 46 and increasing the pressure exerted by the rolls 34 against the rolls 56. It will be clear that on principles of hydrostatics, the pressure wiil be uniform throughout the full length of the rolls. Further, the pressure is adjustable by simple adjustment of the hydrostatic pressure.

Through the use of this invention, feed rolls only three and a half inches in diameter have been used successfully in intermittent operations, on tube widths as great as 48 inches. When the machine is shut down, the hose 54 is connected to atmosphere, whereupon the springs 32 lift the shaft 20 away from the shaft 24, relieving the rolls 34 and 56 of contact pressure, thereby avoiding any possibility of local deformation of either set of rolls, by prolonged static contact and thus greatly lengthening the useful life of the rolls.

A special feature of this invention lies in its ability to accommodate localized variations in pressure occurring across the width of the rolls. Such variations would occur for example: in drawing a gussetted tube where the gussetts have double the number of plies occurring in the rest of the tube. An even more severe condition occurs if one or more of the lower rolls 56 are used to carry out printing or a die-cutting operation. In any case, the upper rolls 34 may yield locally by compression of the tube 54. Since the shaft 20 is of small diameter, the stresses induced by exure are minimized and are not transmitted to distort either the end bearings or the gears. Moreover, slight local compression of the tube 54 has virtually no eect on the pressure exerted by the remaining rolls.

l claim:

l. Means for feeding a web comprising an opposed .ICC

of coaxially mounted rolls, the rolls `of each Y.

' set formingan'elongated, effectively continuous roll of small diameter; a set of ,supporting means between the rolls affording Ysupport` at thepend ,of each roll :againsti Vseparation vof thelpairs'of sets of rolls of each set of cof-A -axially mounted rolls, and vHuid pressuremeans engaging atY leastY one set of supportingY means to press said means and the set` of rolls supported thereby toward the` `other set of: rolls.

2. Means as setY forth in claim 1Y Vincluding '.mean's irresisting said uid Vpressure means and operative to sep arate said setsk of rolls'whenV said uid pressure means 'is inactive. Y d

. 3. A feed roll arrangement comprising: a pair of opposed shafts; arseries oirrolls secured to each shaft;Y aY

seriesrof 'rigidly mounted supportsv journaled on one of said shafts, each support lying between a Ypair of Vthe rollsron such shaft; a'series of pivotallymounted supports *journaled on theV other of said shafts; aexible hose Vvoverlying one end; ofthe lastv named'supports; a'xed 'member overlying said hoseyfand means to'expand said Vhose `to rockl said pivotedrsupports toward said xed supports. Y Y

1 4. A feed roll arrangement as set Yforth in claim 3 including resilient meansV urgingfsaid pivoted supports and the rollssupported thereby away'from said fixed supports yand the rolls supported thereby.

5. Mechanism for operating on advancing webs com- Y K prising: elongatedshaft a series of `rolls secured to said shaft, a series of supports r 4 Y A of relatively small diameter;

each journaled on said shaft between adjacent rolls and xedly pivoted adjacent one end; a flexible hose overlying the opposite ends of said supports; a second shaft'parallelVK to said rst shaft and journaled in iixed supports; means secured to Vsaid secondy shaft for performing periodic operations on afweb passing between the two shafts; a

Viizred member in Contact with the sideof said'hose opposite the side in contact with Ythe ends of said rstY Y supports, and means to expand said hose to rock (said pivoted supports toward said ixed supports.

6. Mechanism according to claim 5 including resilient means urging saidpivoted supports and the Yrolls sup-f ported thereby'away from said fixed supports and the rolls supported thereby.. .Y

References Cited in the le of this patent p' VUPTED STATES PATENTS 1,059,879

Beeson e,. Sept. 15V, 1955 f 'Y

Images