Winding – tensioning – or guiding – Coil holder or support – Radially expansible or contractile
Reexamination Certificate
2000-07-19
2002-06-18
Jillions, John M. (Department: 3653)
Winding, tensioning, or guiding
Coil holder or support
Radially expansible or contractile
C242S530300, C242S576100
Reexamination Certificate
active
06405970
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a core shaft holding and gripping winding cores such as a paper tube for use in winding or unwinding of a sheet material, and more particularly, to an aligning core shaft that prevents runout of the winding cores and the resulting decentering.
2. Statement of Related Art
In winders for winding up a sheet material or unwinders thereof, hitherto a core shaft as shown in
FIGS. 4 and 5
has been widely used, which is provided with lugs
24
interposing lug stays
23
and leaf springs
25
between a shell
21
of the core shaft and a rubber tube
22
in a manner that the lugs can protrude from the shell
21
. The gripping of winding cores A by means of the core shaft is conducted so that when the rubber tube
22
is expanded by air admitted from an air inlet (not shown) into it, the lugs
24
are projected from the outer circumferential part of the shell
21
to come into press contact with the inner diameter of each winding core fitted externally on the core shaft, thus gripping the winding core.
With the conventional core shaft, the rubber tube
22
is located near a radially central part within the core shaft and the magnitude of protrusion of the lugs
24
is set with a sufficient margin to push up the inner surface of the winding core. Because of the construction, when the inside diameter of the shell
21
and the rubber tube
22
are expanded, a still protrudable clearance S′ remains between the shell
21
and the lugs
24
retained within the inside core diameter, and the clearance cannot be kept constant. Consequently, the problem is encountered that the lugs
24
are freely movable by the amount of the clearance. The winding core A is therefore not only decentered, but also cannot be gripped concentrically with the core shaft since the winding core sags downwardly owing to the weights of the rubber tube
22
and the lugs
24
.
Again, when the winding core A in that state is rotated at high speed, the winding core vibrates, so that the sheet-like material thereon cannot be wound stably and the resulting runout of the core causes a variation in the pass length of the sheet material during winding. The tension of the sheet material fluctuates, resulting in wrinkling of the wound product, accordingly.
On the other hand, another winding shaft device is disclosed in JP Patent First Publication No. 3-106744A (1991), which device is constructed so that grip members movable along inclination surfaces may be outthrusted by introduction of compressed air into a shaft body so as to grip winding tubes. Here, it is required that the device have both chuck mechanisms for gripping the winding tubes and clutch mechanisms for rotating the shaft body, and the clutch mechanisms be positioned inside the chuck mechanisms. Because of the construction, the iron core as the shaft body is inevitably so slender that the strength of the shaft is reduced and a deflection of the shaft is caused. Consequently, there is a defect of the difficulty in meeting a high-speed winding.
In particular, the recent requirement of a high productivity in winding of a film necessitates the winding of a wider film. To that end, the width of a film is enlarged to 2500 to 3000 mm against 1000 to 1500 mm in the past irrespective of the same core diameter of 75 mm as before and the winding speed is raised to 300 to 400 m/min.
Aside from the lugs of the known core shafts described above, another means for gripping winding cores concentrically are also known, namely, thread screws, a link mechanism, etc. However, these constructions are complicated and expensive since a number of components must be incorporated in a small space, considering the comparatively small diameter of the core.
In order to overcome the drawbacks or problems of the prior art core shafts, this invention is designed to provide an improved core shaft of the lug type as stated above. Accordingly, an essential object of the invention is to inhibit the movement of lugs within a shell of the core shaft, thereby securing concentrical gripping of winding cores with the core shaft and avoiding decentering and vibration of the winding cores, even upon high-speed winding of a wide film. Another object is ultimately to permit a smooth winding or unwinding of a sheet material.
SUMMARY OF THE INVENTION
The invention for attaining the aforesaid object resides generally in a core shaft of a required length which comprises, as its outer circumference, a plurality of sets of lugs arranged axially in spaced relationship and each protruding from the outer circumference to come into press contact with an inner surface of a winding core externally mounted, thus gripping the winding core. The core shaft is basically characterized in that at least one set of the lugs are disposed circumferentially equidistantly relative to the center of the core shaft; an inner core tube for the passage of air is disposed in a radially central part of the shaft; air cylinders having an inclined wall of a required angle are provided directly on an outer circumference of the inner core tube between the inner core tube and the lugs so that the inclined wall is axially movable; slide fittings having a reverse inclined wall to the inclined wall of the air cylinder are disposed in a manner that the reverse inclined wall is in facing contact with the inclined wall; and the slide fittings are fitted with the lugs so that when the inner core tube and the air cylinders are in communication with each other and air is moved through the cylinders, the inclined walls are moved to protrude the lugs equally or to retract the lugs from the outer circumferential surface of the shaft through the slide fittings.
More specifically, a first core shaft is characterized in that the slide fittings are fitted with the lugs so that when air is admitted into the inner core tube and the inner core tube communicates with the air cylinders, the inclined walls move to protrude the lugs equally from the outer circumference of the shaft through the slide fittings whereas when air is discharged, the inclined walls move in the opposite direction to retract the lugs from the outer circumference through the slide fittings.
In the foregoing core shaft of the construction that air is required to be always injected during winding, the requirement of perpetual injection of air necessitates the use of a number of air cylinders, which in turn requires a number of seal packings for the air cylinders. As a consequence, even if a leakage of air in a slight amount occurs, air pressure is lowered and the protruding force of the lugs is reduced, with the result that gripping force of securely gripping paper tubes or the like cannot be maintained. For that reason, it is also effective that the need for introduction of air during winding is dispensed with and air is introduced only when fitting or removing paper tubes or the like thereby to retract the lugs. That will do away with the need for an air injection device during winding and impede any reduction in the gripping force due to air leakage during winding. A second aspect of the invention is thus offered.
That is to say, a second winding core shaft is characterized in that at least one set of the lugs are disposed circumferentially equidistantly relative to the center of the core shaft on one circumference thereof; an inner core tube for passage of air is disposed in a radially central part of the shaft; air cylinders having an inclined wall of a required angle are provided directly on an outer circumference of the inner core tube between the inner core tube and the lugs so that the inclined wall is axially movable; slide fittings having a reverse inclined wall to the inclined wall of the air cylinder are disposed each in opposed contact with the air cylinder; the slide fittings are fitted with the lugs; and a spring member is fastened within each air cylinder with its one end attached to a spring retainer and its other end fixed to a cutout in the inclined wall of the air cylinder, thus forming an ai
Flynn ,Thiel, Boutell & Tanis, P.C.
Fuji Tekko Co., Ltd.
Jillions John M.
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