Winding – tensioning – or guiding – Tension control or brake – Supply controlled
Reexamination Certificate
1999-11-19
2001-08-28
Rivera, William A. (Department: 3653)
Winding, tensioning, or guiding
Tension control or brake
Supply controlled
C242S597600, C242S599400
Reexamination Certificate
active
06279849
ABSTRACT:
FIELD OF THE PRESENT INVENTION
The present invention relates to the unwinding of wire from a spool and, in particular, to an improved coupling between the spool and a brake drum of an unwinding machine which resists slippage of the spool relative to the brake drum in the circumferential direction during unwinding.
BACKGROUND OF THE INVENTION
Wire is unwound from a spool in many industrial manufacturing operations. Thus, for example, in the manufacture of steel belted radial tires, a plurality of wires
10
are drawn off from an array
12
of spools
14
supported on support frames
16
of an unwinding machine
18
as shown in FIG.
1
. The wires
10
drawn from the spools
14
are then transferred to a calender for combination with rubber prior to a vulcanizing process (not shown).
During the drawing of the wires
10
from the array
12
of spools
14
shown in
FIG. 1
, it is desirable to control the tension applied in the wires
10
, with the degree of tension depending in part upon the gauge of the wire being drawn. Thus, for example, in the manufacture of steel belted radial tiers for small cars, tension upwards of 0.1836 Newtons (i.e., “1.8 Kg”) is desirable. However, in the manufacture of earth moving vehicular tires utilizing ⅜ in. diameter wire, tension upwards of 0.9180 Newtons (i.e., “9 Kg”) is desirable.
A conventional method utilizes a magnetic chuck
20
as shown in
FIG. 2
for the coupling of a spool
14
to a brake drum
22
of an unwinding machine
18
as shown in FIG.
1
. During the unwinding process, selective braking of the brake drum
22
results in the application of the desired tension in the wire
10
that is drawn from the spool
14
.
The conventional magnetic chuck
20
shown in
FIG. 2
includes a magnet
24
disposed within a disc-like housing
26
including a lip
28
having a continuous planar surface
30
generally transverse to an axis
32
of a spindle
34
upon which it is rotatably supported. The spool
14
includes opposed identical ends
36
each having a plurality of radial ribs
38
formed in an end surface
40
for strengthening of the end
36
of the spool
14
. A circular recess
42
is also defined by the end
36
of the spool
14
having a generally planar, annular surface
44
surrounding an axial passage
46
that extends through the center of the spool
14
. The spool
14
is rotatably supported on the spindle
34
by extension of the spindle
34
through this passage
46
.
The magnetic chuck
20
is secured to the brake drum
22
by conventional fasteners
48
. The magnet
24
itself is adhered to a base
50
of the housing
26
using an adhesive. The lip
28
of the housing
26
extends axially away from the base
50
to surround the magnet
24
. The magnet
24
magnetizes the continuous planar surface
30
of the lip
28
.
The spool
14
is secured to the magnetic chuck
20
by magnetic engagement between the planar surface
30
of the lip
28
and the annular planar surface
44
of the recess
42
formed in the end
36
of the spool
14
.
The arrangement of
FIG. 2
performs well in the manufacture of steel belted radial tires in which the tension in the wires does not exceed approximately 0.1836 Newtons (“1.8 Kg”). However, once this upper limit is exceeded, the spool
14
retained simply through magnetic attraction against the planar surface
30
begins to slip thereon. Consequently, tension in the range of 0.9180 Newtons (“9 Kg”)cannot be achieved using this conventional arrangement.
A known solution for achieving the higher desired tension includes the provision of a pin on the brake drum which extends within a bore of the spool for locking engagement therewith (not shown), whereby the spool would be physically precluded from rotating relative to the brake drum without first severing or bending of the locking pin. While such an arrangement is effective in achieving the desired tension, play between the pin and the bore in the spool leads to clanking and other undesirable noise during rotation of the spool in unwinding of the wire. Moreover, when a large plurality of spools simultaneously are being unwound as shown in
FIG. 1
, the noise becomes so great that ear protection must be worn by an operator attending to the unwinding machine.
Another disadvantage to this arrangement is that in the loading of a new spool of wire onto a spindle of the support frame, the bore in the side of the spool must be aligned with the locking pin disposed on the side of the brake drum for proper positioning of the spool on the spindle. While this may not be exceptionally tedious for the loading of a single spool, this task is impractical with a large array of spools as shown in FIG.
1
.
Yet a third disadvantage to this arrangement is that during rotation of the spool on the spindle, the spindle tends to move away from the brake drum off of the locking pin and, consequently, an operator must constantly monitor the array of spools to insure that each is properly maintained in position on its spindle.
In view of the above conventional arrangements for unwinding wire from spools, it is clear that a need exists for an improved apparatus and method by which higher levels of tension easily exceeding 0.1836 Newtons (“1.8 Kg”)can be achieved without encountering the foregoing disadvantages.
SUMMARY OF THE INVENTION
Briefly summarized, the present invention relates to a coupling between a spool of wire and a brake drum on an unwinding machine. The coupling is accomplished by a magnetic chuck which, in accordance with the present invention, includes: (1) a metallic base having a first axial opening formed therein for extension of a spindle therethrough; (2) a metallic rim disposed about the first axial opening and integral with and extending in a generally axial direction from the base, with the rim including an edge having a discontinuous planar surface disposed substantially orthogonal to the axial direction; and (3) a magnet integral with the base that magnetizes the discontinuous planar surface of the rim.
Features of the magnetic chuck of the present invention include: the edge having a stepped profile resembling a rectangular wave; the rim being circular and coaxial with the axial opening in the base; and, the magnet including a second opening formed in register with the first opening in the base for extension of the spindle therethrough.
The apparatus for unwinding of wire from a spool in accordance with the present invention includes a spindle associated therewith that is disposed in a generally horizontal orientation on a support frame. The spool includes opposed ends and defines an axial opening therebetween through which the spindle extends for rotatable support of the spool on the spindle. An end of the spool is metallic and includes ribs formed in an end surface thereof for reinforcement of the end of the spool. A shaft collar preferably comprising a brake drum defines an opening through which the spindle also extends for support thereof on the spindle, with the brake drum being disposed between the spool and the support frame.
In accordance with the present invention, the magnetic chuck is disposed about the spindle between the spool and the brake drum. In particular, the magnetic chuck is secured by fasteners to the brake drum for rotation therewith about an axis of the spindle. Furthermore, the discontinuous planar surface of the edge of the magnetic chuck extends between the ribs of the spool into abutment with the end surface of the spool that is disposed between the ribs. The magnetic chuck thereby magnetically engages the metallic end of the spool and couples the spool to the brake drum for rotation therewith about the spindle.
The magnetic engagement of the spool between the ribs has been found to improve resistance to slippage of the spool in a circumferential direction relative to the magnetic chuck and the brake drum. Consequently, greater tension may be applied to wire being unwound from the spool compared with the tension that may be applied through the aforesaid conventional magnetic chuck of FIG.
2
.
In addition to
Kennedy Covington Lobdell & Hickman LLP
McCoy-Ellison, Inc.
Rivera William A.
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