Abstract:
A vertically adjustable web slitter is adapted to be supported by a track of a web-slitting machine, and comprising an input port adapted to receive pressurized fluid. Also, a control assembly is adapted to controllably transmit the pressurized fluid into any one of a set of first fluid passageways. A cylinder is adapted to receive the pressurized fluid from one of the first fluid passageways. A piston, having a first end and a second end, is set into the cylinder and is adapted to be driven within the cylinder by the pressurized fluid. Further, a set of actuators that are adapted to be driven by pressurized fluid are separated by the piston and cylinder from the set of first passageways. Finally, the piston defines at least one second fluid passageway extending from the first end to the second end. A first flexible hose connects each second fluid passageway to a first fluid passageway and a second flexible hose operatively connects each second fluid passageway to one of the actuators.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a web slitter for cutting an endless web. 
     A web-slitting machine or system typically employs a number of web-slitting assemblies to cut an endless moving web, such as a continuous roll of paper or other material, into a number of strips (equal to the number of web-slitting assemblies plus one). The web-slitting machine supports and permits the positional adjustment of the web-slitting assemblies, thereby permitting the machine to be configured to cut any one out of a wide variety of strip width sets. 
     Referring to FIGS. 1 and 2, a prior art web-slitting assembly  10  includes a web slitter  12  that overlaps with a lower knife  22 , so that together they present a scissors-like action to a continuous web of material which is pulled through the assembly  10  by a drum or a take-up reel (not shown). The web slitter  12  includes an upper carriage  16 , which is slideably movable along a support in the form of a transverse bar  14 , and a blade holder  18  that includes a freely rotating disk-shaped blade  20 . The lower knife  22 , which may be in the form of a drum or roller that has a sharpened edge, is positioned on a supporting sleeve  24 . 
     Referring to FIG. 2, the upper carriage  16  of web slitter  12  includes a brake shoe  26 , which engages a dovetail-shaped projection  15  of the transverse bar  14 . The brake shoe  26  may be operated pneumatically or by turning rotary brake knob  28 . The transverse position of the carriage assembly  16  along the transverse bar  14  is adjusted by turning transverse control knob  30 , which is connected to a shaft  32  (FIG. 2) which terminates in a pinion gear  34 . 
     The upper carriage  16  is connected to the blade holder  18  by a dovetail-shaped guide key  38 , which is selectively removable from the upper carriage  16 . An added feature of this construction is that the blade holder assembly  18  may be reversed relative to the upper carriage  16  by merely sliding the blade holder assembly  18  off of the guide key  38 , rotating it 180°, and sliding it back on, thus permitting either a right-hand or left-hand orientation. 
     A rotary control knob  52  provides mode control for the pneumatic systems, which power the locking of the upper carriage  16  to the transverse bar  14 , the lowering of the blade holder assembly  18  toward the knife  22 , and the shifting of the rotary blade  20  laterally toward the knife  22 . More specifically, the control knob  52  permits an operator to command standby, setup or run mode. In standby mode, blade holder  18  is held at a raised and disengaged position. To function properly during run mode, the blade  20  and knife  22  must press against each other with a force that is within a proper range. If the force is too light or nonexistent, the web may not be slit. If the force is too great, the blade  20  may break. Accordingly, in run mode, blade holder  18  is not only lowered, but also moved to the side by a side-shift cylinder (not shown) having a maximum cylinder stroke distance. If carriage  16  has been correctly positioned on bar  14 , this will cause blade  20  to contact and press against the knife  22  with an acceptable force. In setup mode, blade holder  18  is lowered and shifted to the side by the side-shift cylinder, thereby permitting an operator to move the web slitter  12  along the transverse bar  14  and to thereby place and press the blade  20  against the knife  22 . By locking the carriage  16  in place at the resultant position the operator has readied web-slitting assembly  10  for run mode operation. However, the operator must exercise judgment and skill for the blade to press with an acceptable force against the knife  22  during run mode. 
     U.S. Pat. No. 5,058,475, referenced and incorporated above, simplifies the task of the operator by providing a “half-stroke” button. This button, when depressed, causes the side-shift cylinder to be stopped half-way through its stroke. During setup mode, an operator can depress the half-stroke button and move the web slitter  12  laterally along the transverse bar  14  so that the blade  20  contacts the lower knife and locks the carriage in place at the resultant location. After this, during run mode, the blade  20  will contact the knife  22  half-way through the stroke of the side-shift cylinder, with the remaining pneumatic pressure introduced into the side-shift cylinder pressing the blade against the knife  22 . This “half-stroke” amount of force is approximately the optimum amount of force for the blade  20  to press against the knife  22 . This innovation provided a definite advantage over the prior art of the time. Unfortunately, in practice it has been found that operators sometimes forgot to depress the “half-stroke” button during setup mode, thereby completely nullifying the affect of this button. 
     It is important in the design of web slitting machines that the shear or cant angle between the blade  20  and lower knife  22  be set precisely. The cant angle is the angular relationship between the blade  20  and the lower knife  22  in the plane of the blade  20  about a vertical axis. This angle must be set accurately so that the wear and deformation between the two cutting edges are kept to a minimum. 
     The need for accuracy in the setting of the cant angle complicates the performance of the following described reconfiguration of a web-slitting assembly. A blade  20  that is positioned to cut against a first edge of a knife  22  at a first cant angle will eventually wear away the first edge. It is then desirable to switch the relative positions of the blade  20  and the knife  22  so that the blade  20  makes contact with the knife&#39;s second edge, which is unworn. As shown in FIG. 1, the blades  20  are asymmetrically shaped to have a knife-contacting-side and a side that never contacts a knife  22 . As a result, when it is desired to shift the blade arrangement so that the blade  20  contacts the knife  22  at the knife&#39;s second edge, it is necessary to reorient the blade  20  by about 180°. As noted earlier, a simple 180° rotation can be effected simply by sliding the blade holder  18  off of the guide key  38 , rotating it 180°, and sliding it back on. 
     Unfortunately, the cant angle of the blade  20  also must be shifted to a mirror image angle of the first cant angle relative to a plane parallel with the faces of knife  22 . Heretofore, there appears to have been no method for quickly and easily effecting this shifting of the cant angle, forcing the operator to make a time-consuming manual cant angle adjustment. 
     Another problem is encountered in that different makes of web-slitting machines have differently shaped bars (such as bar  14 ) for supporting web slitters. Heretofore, as a result, a web slitter had to be manufactured specifically to be accommodated by the bar shape of a particular make of web-slitting machine. 
     In addition, a problem is encountered in a system such as that of FIGS. 1 and 2 in which a removable blade holder  18  is supported by a piston that is housed in a cylinder (not shown) in the carriage  16  and that is driven down to engage the blade  20  with the knife  22  and driven up to disengage blade  20 . If the blade holder  18  also includes one or more pneumatic actuators, the task of supplying these actuators with pneumatic pressure in the carriage  16  has typically been performed by a set of external hoses (not shown), each linking a source of pneumatic pressure to a receive port in the blade holder  18 . The advantage of this arrangement is that the hoses circumvent the piston and accommodate the various distances between the carriage pneumatic pressure sources and the blade holder  18 . A disadvantage of this arrangement, however, is that every time the blade holder  18  is replaced or reoriented, the hoses must be disconnected and reconnected. An additional disadvantage is that the hoses are exposed and therefore vulnerable to damage by operating personnel. 
     Yet another problem is encountered in a system, such as the one described above, in which a piston (not shown) moves the blade holder  18  up and down. When the piston is moved up, it creates a momentary drop in air pressure in the lower portion of its host cylinder. This drop in air pressure tends to draw the lint-filled air of the blade-slitting environment into the lower portion of the cylinder, thereby degrading system performance over time. 
     SUMMARY 
     The present invention is an improvement of the web slitter shown in the aforementioned U.S. Pat. No. 5,058,475 incorporated herein. 
     In one preferred aspect of the web slitter, a carriage and a blade holder are releasably and matingly interconnected by a connective assembly enabling selective reversal of the blade holder between opposing orientations about a vertical axis. A blade cant angle adjustment assembly enables a choice of either a first predetermined blade cant angle or a second predetermined blade cant angle, each adapted for a respective different one of the opposing blade holder orientations. 
     In another separate preferred aspect, a blade positioning assembly, in response to user selection of a setup mode, automatically moves the blade over only a predetermined partial portion of its maximum horizontal travel distance. 
     In another separate preferred aspect, the web slitter assembly is adapted to be fastened selectively to respective first and second web slitter tracks of different configurations. 
     In another separate preferred aspect, a first fluid passageway is located on one side of a piston which provides vertical adjustment of the blade. An enclosed second fluid passageway circumvents the piston to communicate between the first passageway and an actuator which moves in unison with the piston on the opposite side thereof. 
    
    
     The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a portion of a prior art web slitting machine, showing two web slitting assemblies. 
     FIG. 2 is a side view of a carriage of the web slitting machine of FIG.  1 . 
     FIG. 3 is a perspective view of a web slitter according to the present invention. 
     FIG. 4 is a perspective view of the web slitter of FIG. 3 in a state of partial disassembly. 
     FIG. 5 is a side view of the web slitter of FIG.  3 . 
     FIGS. 5A and 5B are partial side views of web slitters that represent alternative embodiments of the present invention. 
     FIG. 6 is a cutaway partial side view of the web slitter of FIG.  3 . 
     FIG. 7A is a cross-sectional view of the web slitter of FIG. 3, with an adjustment element removed, taken along line  7 — 7  of FIG.  6 . 
     FIG. 7B is a cross-sectional view of the web slitter of FIG. 3, with the adjustment element of FIG. 7A inserted, taken along line  7 — 7  of FIG.  6 . 
     FIG. 8 is a cutaway side view of the blade holder portion of the web slitter of FIG.  3 . 
     FIG. 9A is a cutaway front view of the blade holder portion of the web slitter of FIG. 3 as it appears in standby mode. 
     FIG. 9B is a cutaway front view of the blade holder portion of the web slitter of FIG. 3 as it appears in half-shifted mode. 
     FIG. 10A is a side view of the quick lock and release mechanism of the web slitter of FIG. 3, in its release state. 
     FIG. 10B is a bottom view of the quick release and lock mechanism of FIG.  10 A. 
     FIG. 11A is a side view of the quick lock and release mechanism of the web slitter, in its lock state. 
     FIG. 11B is a bottom view of the quick lock and release mechanism of FIG.  11 A. 
     FIG. 12 is a partially sectional side view of the locking pin assembly of the web slitter of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     One preferred embodiment of a web slitter  110  according to the present invention includes a blade holder  112 , supported by and depending downwardly from a carriage  116 . In turn, carriage  116  has a bracket  118  (FIG. 5) for attaching to a support in the form of a dovetail-shaped transverse rail (not shown but similar or identical to rail  14  of FIG.  1 ). Bracket  118  is connected to the body of carriage  116  by a set of countersunk screws  220 . A bolt  224  may be manually tightened to fasten bracket  118  to the rail. In an alternative embodiment, shown in FIG. 5A, a pneumatic actuator  226  is used to fasten bracket  118  to the rail. Referring to FIG. 5B, a second, alternative, bracket  228  may be attached to the body of carriage  116  to enable it to be fastened to a differently shaped rail, for example the rail of a competing web slitting machine manufacturer. 
     The blade holder  112  holds a circular blade  122  that engages with a lower knife  123  (FIGS. 9A and 9B) in order to slit a passing web. A blade positioning assembly that includes a control knob  120  permits an operator to command standby, setup or run mode. In standby mode, carriage  116  is shortened at an accordionized protective cover  130 , so that blade holder  112  is held at a raised and disengaged position. In run mode, blade holder  112  is lowered and blade  122  is side-shifted, so that if correctly adjusted by an operator, it will contact and press against the lower knife  123  with an acceptable force. In setup mode, blade holder  112  is lowered and blade  122  is automatically side-shifted by half the run mode side shift distance. This permits an operator to move web slitter  110  laterally to place the blade  122  against the lower knife  123 , lock the carriage  16  in place at the resultant position, and have confidence that during run mode, the blade  122  will press with an acceptable force against the lower knife  123 . 
     Referring to FIGS. 8,  9 A and  9 B, the physical construction of the side-shift mechanism is as follows. Inside blade holder  112  there is a metal block  124 , which is fixed in place relative to the top of blade holder  112 . Set into block  124  is a side-shift cylinder  126  that pushes out a peg  128 , which in turn pushes against a hinged parallelogram  131 . A pair of springs  129  urge parallelogram  138  back into position when peg  128  is retracted. FIG. 9B shows peg  128  pushing parallelogram  131  to the right, which in turn shifts blade  122  to the right. Also resident in block  124  is a half-stroke actuator  132 , which extends a notched arm  134 . In standby mode (not shown) notched arm  134  is placed in its highest position and blade  122  is left in its unshifted standby mode position. During set-up mode, as shown in FIG. 9B, arm  134  is placed in its lowest position so that blade  122  is blocked after being shifted by one half the full stroke of side-shift cylinder  126 . An operator can then slide carriage  116  until blade  122  contacts knife  123  and lock carriage  116  into place on mating transverse bar (not shown) at the resultant position. In run mode arm  134  is raised all the way, as it is in standby mode, and parallelogram  131  and blade  122  are shifted by cylinder  126  until the blade  122  encounters and is stopped by the knife  123 , resulting in a good tension between the blade  122  and the knife  123 . 
     As noted in the BACKGROUND OF THE INVENTION section, after a blade  122  has been in position contacting a first side of a knife  123 , it is sometimes desirable to reconfigure the web-slitting machine so that so that the blade  122  contacts the second side of the knife  123 . Because only one side of blade  122  is adapted to contact a knife  123 , the operator must reorient blade holder  112  (and shift the position of the corresponding knife  123 ) in order to effect this reconfiguration. FIG. 4 shows a carriage-to-blade holder connector in the form of dovetail bar  140  protruding from carriage  116  that slidingly and matingly connects with a blade holder-to-carriage connector in the form of a dovetail bracket  142  positioned at the top of blade holder  112 , facilitating the removal and reoriented reattachment of blade holder  112 . 
     This is not all that is necessary, however, because the blade  122  must be canted slightly inwardly (relative to a vertical plane flush with the plane of the contacted side of the knife  123 ) toward the knife surface toward the contacted knife surface. If the blade were only rotated 180°, the blade  122  would be canted slightly outwardly and would not perform correctly. 
     Accordingly, in a preferred embodiment, a cant angle adjustment assembly including a removable key  150  is provided to facilitate the reconfiguration of the slitting machine. Referring to FIGS. 6,  7 A and  7 B, the removable key  150  has a thick arm  152  and a thin arm  154  that fit about a guidepost  156  that is internal to the carriage  116 . This rotates the blade holder  112  about point  158  (FIGS.  7 A and  7 B), thereby orienting the blade  122  with a proper cant angle for cutting with a knife  123  that is to its right. The key  150  may be removed, turned over and reinserted so that thick arm  152  is to the right of guide post  156 , thereby reorienting the blade  122  for cutting against a knife  123  that is to its left. It should be noted that this adjustment can be made entirely by hand, without the use of any tools. The automatic nature of this adjustment, together with the fact that it can be performed without tools, greatly eases the task of web processing plant personnel. 
     As noted in the BACKGROUND OF THE INVENTION section, the prior art includes web slitters having a rotatable blade cartridge that attaches to a carriage. In some cases, the rotatable blade cartridge is operatively connected to the carriage by way of a hose or set of hoses extending external to the cartridge and carriage. This configuration has the advantage that the hoses accommodate different piston positions. It has the disadvantage, however, that the hoses must be disconnected and reconnected every time a cartridge is replaced or reoriented by 180°. In addition, the external hoses are subject to damage by operating personnel. 
     Referring in particular to FIG. 6, the carriage  116  has a pneumatic input port  230  that transmits compressed air to a control assembly  232 , which directs the compressed air into one or a combination of carriage resident fluid passageways  234  in dependence on the position of control knob  120 . A cylinder  190  houses a piston  163  that divides cylinder  190  into a first chamber  192  and a second chamber  194 . A set of three flexible hoses  161  transmit the pneumatic signals of the rest of the fluid passageways  234  to the top of a piston  163  where it is transmitted through a set of first fluid passageways  166  and then through a second set of flexible hoses  167 , which extend to carriage-to-blade holder connector  140 . A set of three carriage connector fluid passageways  176  extend through connector  140  and terminate at the bottom of connector  140  in a set of openings  172  fitted with gaskets  174  (see FIGS. 10B and 11B.) In turn, the openings  172  mate with a set of blade holder fluid passageways  178  that extend through blade holder  112  and that are plumbed to the blade guard actuator (not shown), the side-shift cylinder and the half-stroke actuator  132 , respectively. 
     The advantages of this system should now be apparent. The two sets of hoses  161  and  167  are safely hidden within carriage  116  and are thereby protected against breakage by operating personnel. In addition, blade holder  112  may be removed from carriage  116  and reattached without the need to detach and reattach any hoses, thereby greatly easing the task of replacing or reorienting a blade holder  112 . 
     As noted previously, the blade holder  112  may be removed from the carriage  116 , rotated 180° and reattached. Referring to FIGS. 8,  10   b  and  11   b  there are three carriage connector fluid passageways  176   a ,  176   b  and  176   c  and corresponding openings  172 . Two of the three mating blade holder fluid passageways  178   a ,  178   b , each have two openings. This is so that a first pair of openings of  178   a  and  178   b  can be mated with  176   a  and  176   b  respectively when blade holder  112  is in a first orientation but the other pair of openings of  178   a  and  178   b  can be mated with  176   a  and  176   b  respectively when blade holder  112  is in a second orientation, which is rotated 180° from the first orientation. Accordingly, the blade holder is pneumatically controlled in the exact same manner in either orientation. Fluid passageway  176   c  always mates with the single opening of fluid passageway  178   c.    
     As noted in the BACKGROUND OF THE INVENTION section, in prior art systems, air filled with dust or lint would be sucked into the lower chamber defined by the lower side of piston  163 , when piston  163  was raised to disengage blade  122  at the end of run mode. In a preferred embodiment of the present invention, this problem is defeated by the addition of a pressurized fluid injection mechanism in the form of a three orifice valve  180 , having a lower orifice  182  at the bottom of piston  163 , an upper orifice  184 , opening at the top of piston  163  and a side orifice  186  opening at the fluid passageway  166  that transmits the side shift cylinder air pressure through piston  163 . This valve is so constructed that when the air pressure at orifice  184  falls below the air pressure at side orifice  186 , the air pressure from side orifice  186  is shunted to lower orifice  182  and into the second chamber  194 . This coincides with the time when air needs to be vented from the side shift cylinder (not shown), so a fortuitous blast of air from side shift cylinder to the bottom chamber  194  both permits the side shift cylinder to shift back and also prevents dust and debris laden air from entering the bottom chamber. 
     Referring to FIGS. 10A,  10 B,  11 A,  11 B and  12 , a blade holder quick lock and release mechanism is shown for locking and releasing the dovetail bar  140  to the bracket  142 . A locking bar movement assembly permits an operator to move a locking bar  204  so that it presses and locks against a side of the bracket  142 . More specifically, a manual adjustment element in the form of a lever  144  is adapted to be moved about hinge  200  by a human operator, causing cam surface  202  to push back (move to the left in the figures) a locking bar  204  when lever  144  is moved up and permitting a pair of springs  206  to push locking bar  204  forward (to the right in the figures) when lever  144  is moved downwardly. A pair of pins  208  that protrude downwardly from locking bar  204  each fit into a slanted slot  210  in dovetail bar  140 . Accordingly, when locking bar is pushed back by cam surface  202 , it is also moved inwardly, to release dovetail bar  140  from bracket  142  and permit bracket  142  and thereby blade holder  112  to be slid out from dovetail bar  140 . Conversely, when lever  144  is moved downwardly permitting springs  206  to push the locking bar  204  forward, the locking bar  204  is also moved outwardly by way of pins  208  and slots  210 , thereby locking dovetail bar  140  into bracket  142 . 
     Referring to FIG. 12, an extra safeguard in the form of a locking pin assembly  212  is included as part of blade holder  112 . A locking pin  214  mates with one of a pair of receptive apertures  216  depending on the relative orientation of blade holder  112  and carriage  116 . A cross bar  218  is threaded through an aperture (not shown) in locking pin  214  to permit an operator to quickly and easily remove the pin  214  from the receptive aperture  216 , thereby permitting blade holder  112  to be removed from carriage  116 . A pair of springs  222  urge cross bar  218 , and thereby locking pin  214  upwardly, so that an operator must affirmatively pull down on cross bar  218  in order to release blade holder  112 . 
     The terms and expressions which have been employed in the foregoing specification are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.