Cutting – Rotatable disc tool pair or tool and carrier – Means to separate elements of tool pair
Reexamination Certificate
2000-04-28
2004-05-11
Peterson, Kenneth E. (Department: 3724)
Cutting
Rotatable disc tool pair or tool and carrier
Means to separate elements of tool pair
C083S500000, C083S506000
Reexamination Certificate
active
06732625
ABSTRACT:
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'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'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
Boynton Blane G.
Holbert Richard M.
Miller William R.
Shinn Robert F.
Chernoff Vilhauer & McClung & Stenzel
Flores-Sánchez Omar
Peterson Kenneth E.
Tidland Corporation
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