Winding – tensioning – or guiding – Convolute winding of material – With particular drive
Reexamination Certificate
2001-02-22
2002-07-23
Jillions, John M. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
With particular drive
C242S545000, C242S545100
Reexamination Certificate
active
06422502
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a winding unit for intermittently winding a web such as a tape.
This type of winding unit is used to wind a web fed from an intermittently operating processing stage in synchronization with the operating pitch of the processing stage. For example, it is used to wind a cover tape (also called top tape) which has transported electronic parts such as semiconductor chips in pockets of the tape, or to take up a cleaner sheet used to clean the fixing unit of a copier or a printer.
FIGS. 24 and 25
show a winding unit used to wind a cover tape
60
after it has transported semiconductors. A reel
61
of the winding unit includes a support reel
62
having a reel boss portion
62
′ and a detachable reel
78
mounted on the reel boss portion
62
′ so as to be not rotatable relative to the reel boss portion. The cover tape
60
is wound around the detachable reel
78
. This winding unit has a one-way clutch
63
for driving and a one-way clutch
64
for braking mounted in an inner peripheral surface of a reel boss portion
62
′. The one-way clutch
63
for driving is mounted on a stepped fixed shaft
67
through a rotary sleeve
66
having a pivoting lever
65
, while the one-way clutch
64
for braking is directly mounted on the fixed shaft
67
.
The fixed shaft
67
is fixed by a bolts
69
to a bracket
68
, which is fixed to a base
79
(
FIG. 24
) by bolts
80
. Thus the rotary sleeve
66
is prevented from coming off the shaft
67
by the bracket
68
.
The pivoting lever
65
is intermittently pivoted by a predetermined angle (shown by arrow A in
FIG. 24
) in synchronization with the pitch of supply of semiconductor chips. At this time, the one-way clutch
63
for driving locks the reel boss portion
62
′ and the rotary sleeve
66
together, and the support reel
62
rotates a predetermined angle together with the rotary sleeve
66
to wind the cover tape
60
around the reel
61
. When a predetermined length of cover tape
60
has been wound, the pivoting lever
65
is returned to the original position by a coil spring
70
. At this time, the one-way clutch
64
for braking locks the reel boss portion
62
′ and the fixed shaft,
67
together, so that only the pivoting lever
65
and the rotary sleeve
66
return to the original positions.
The one-way clutches
63
and
64
have on the inner peripheral surfaces of their outer rings
71
and
72
a plurality of cam surfaces inclined in the circumferential direction. At positions opposite to the respective cam surfaces, rollers
73
and
74
are mounted. The rollers
73
and
74
are biased by springs
75
and
76
, respectively, in such directions that they are locked by the cam surfaces. The one-way clutches
63
and
64
are axially separated from each other by a shoulder
77
formed on the inner peripheral surface of the reel boss portion
62
′ so as not to interfere with each other.
With this winding unit, when the reel
61
becomes full of the wound cover tape
60
, it is necessary to dismount the detachable reel
78
from the support reel
62
for replacement.
But since the support reel
62
is braked by the one-way clutch
63
for braking and cannot turn in reverse, tension during winding still acts on the cover tape
60
. This makes it difficult to dismount the detachable reel
78
.
An object of this invention is to provide a winding unit in which during replacement of the reel
78
, the reel can be rotated in reverse direction so that the tension in the cover tape
60
can be released.
SUMMARY OF THE INVENTION
According to this invention, there is provided a winding unit for winding a web, the winding unit comprising a fixed shaft, a rotary sleeve having a lever and rotatably mounted on the fixed shaft, a support reel having a reel boss portion, a reel detachably mounted on the reel boss portion, a one-way clutch for driving and a one-way clutch for braking each having an outer ring formed with a plurality of circumferentially inclined cam surfaces on an inner peripheral surface thereof, rolling elements mounted at positions opposing the respective cam surfaces, and springs for biasing the rolling elements in such directions as to be locked by the cam surfaces, the one-way clutches being mounted in the reel boss portion, the one-way clutch for driving being mounted on the fixed shaft through the rotary sleeve, the one-way clutch for braking being mounted on the fixed shaft, the reel being intermittently rotated by pivoting the pivoting lever to wind the web on the reel, a torque limiter being provided between the outer ring and the reel boss portion to shut off transmission to the outer ring of a turning torque in the unwinding direction applied to the reel boss portion.
With this arrangement, either during the intermittent web winding periods or during intermittent rest periods, the torque limiter assures winding without producing any slip, and the web maintains a constant tension due to the function of the one-way clutch for braking. When necessity of releasing the tension in the web arises e.g. during replacement of the reel, by forcibly turning the reel in the unwinding direction, the reel will turn while slipping relative to the outer ring to release the tension in the web.
More specifically the torque limiter is set so as to have a sufficiently large winding torque value for the transmission of torque in the winding direction from the outer ring to the reel boss portion and to have a predetermined unwinding torque value for the transmission of a torque in the unwinding direction from the reel boss portion to the outer ring. When the reel boss portion is forcibly turned with a torque exceeding such an unwinding torque value, slip occurs.
As a further specific structure, the torque limiter is a spring type torque limiter comprising a torque limiter ring mounted on an outer peripheral surface of the outer ring, and a coil spring mounted on an outer peripheral surface of the torque limiter ring with a predetermined binding force, the coil spring has one end thereof engaging the reel boss portion, the coil spring being adapted to lock when the torque limiter ring rotates in the winding direction so that the binding force increases, and to have a predetermined unwinding torque value when the reel boss portion rotates in the unwinding direction so that the binding force decreases.
A restraining means for the coil spring may be provided on the reel boss portion to prevent one end of the coil spring from moving in the circumferential direction. With this arrangement, when winding around the reel is performed by pivoting the pivoting lever, movement of the coil spring relative to the reel boss portion is prevented by the restraining means, so that the pivoting angles of the pivoting lever and the reel coincide with each other.
The coil spring may have the other end thereof engaging a lid member fitted in the end of the torque limiter ring.
The torque limiter may be a press-in type torque limiter in which the torque limiter ring is pressed in the reel boss portion.
Also, there is provided a structure wherein the torque limiter is a cam type torque limiter comprising a torque limiter ring pressed in the reel boss portion, cam recesses formed in one of the torque limiter ring and the reel boss portion, rolling elements housed in pockets formed in the other thereof so as to oppose the cam recesses, and resilient members each housed in the respective pocket for biasing the rolling elements toward the cam recesses.
As a further specific structure of the cam type torque limiter, there is also provided a structure wherein the torque limiter ring has a rolling element retaining portion on a radially outer side thereof and a resilient member retaining portion on a radially inner side thereof, the rolling element retaining portion being formed with a plurality of pockets at angular spacings so as to radially extend therethrough, the rolling elements being housed in the respective pockets and biased from a single resilient member housed in the resi
Takada Seiichi
Yoshioka Atsushi
NTN Corporation
Wenderoth , Lind & Ponack, L.L.P.
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