Sheet feeding or delivering – Feeding – Separator and conveyor
Reexamination Certificate
2002-05-09
2003-09-09
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
Separator and conveyor
C271S109000, C271S314000, C271S272000, C271S264000
Reexamination Certificate
active
06616136
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a friction plate coupling structure. More particularly, the present invention relates to the friction plate coupling structure of an automatic document feeder.
2. Description of Related Art
Due to the rapid development of image input, processing and amending equipment, a scanner has become an indispensable peripheral device for a computer system. The scanner is capable of scanning text or image data from documents, journals, books and pictures and feeding the data into a computer for further treatment.
Among scanners, a platform scanner is the most common type. Inside a platform scanner, the scanning module shuttles forward and backward underneath a transparent platform so that a document placed on top of the transparent panel can be scanned. The scanning module has no driving power of its own and hence has to be driven by an external driving system that includes a stepper motor, a set of gears and a transmission belt. Before scanning, the document is placed atop the transparent platform and a document cover is lowered to flatten out the document on the transparent platform.
However, when the number of documents that needs to be scanned is considerable, using a simple platform type scanner to scan the documents is quite cumbersome and time-consuming. To simplify and speed up the scanning operation, an automatic document feeder (ADF) is often attached to the platform scanner. The automatic document feeder is a simple delivering device that transfers each document in a pile onto the platform sequentially for scanning.
FIG. 1
is a schematic side view of a conventional platform type scanner with an automatic document feeder thereon. As shown in
FIG. 1
, an automatic document feeder
100
sits atop the platform scanner
200
.
FIG. 2
is a perspective view showing some internal components of the automatic document feeder in FIG.
1
. The automatic document feeder
300
mainly comprises a body casing
310
, two rollers
320
,
322
, a gearset
330
, a shaft
340
, two friction plates
350
,
352
and a torsion spring
360
.
FIG. 3
is a magnified view of area
3
of the automatic document feeder as shown in FIG.
2
.
The shaft
340
is attached to the upper rear side of the body of a movable cover
110
of the automatic document feeder
100
. The shaft
340
may rotate around a central axis when driven by a driving mechanism (not shown). The shaft is attached to the body casing
310
via a bearing so that the shaft
340
may rotate without affecting the casing
310
. The rollers
320
,
322
and the gearset
330
are also attached to the interior of the body casing
310
. The roller
320
is joined to the shaft
340
. The axis of both the roller
320
and the shaft
340
are concentric and the roller
320
can be driven into rotation through the shaft
340
. The roller
322
is attached to the body casing
310
through a pair of bearings and hence is capable of rotating. The axis of the roller
322
is parallel to the axis of the roller
320
. The gearset is set up between the shaft
340
and the roller
322
so that the roller
322
is able to rotate in an identical direction as the shaft
340
when driven by the shaft
340
.
The two friction plates
350
,
352
and the torsion spring
360
are set up on the shaft
340
on the left side of the roller
320
inside the body casing
310
. The friction plate
350
has a tubular sleeve profile tightly engaged to the shaft
340
. The friction plate
350
rotates together with the shaft
340
. The friction plate
352
also has a tubular sleeve profile and slides movably (indirectly) over the shaft
340
. Hence, the friction plate
352
is only indirectly driven by the shaft
340
. The torsion spring
360
is clamped between the friction plate
352
and the body casing
310
. One end
362
of the torsion spring
360
is fastened to the body casing
310
while the other end is fastened to the friction plate
352
. Through a compression of the torsion spring
360
, the friction plate
352
is pushed to the right pressing against the friction plate
350
. Utilizing frictional force between the two friction plates
350
and
352
, a rotation of the friction plate
350
drives the friction plate
351
and twists the torsion spring
360
as well. Consequently, the body casing
310
also rotates relative to the central axis of the shaft
340
.
FIG. 4
is a front view showing the relative positioning of the shaft
340
, the body casing
310
, the torsion spring
360
, the friction plates
350
,
352
and the gearset
330
inside an automatic document feeder
300
.
The following is a brief description of the action taken by a paper feed unit to bring a document into the platform scanner.
FIG. 5
is a schematic side view showing the configuration of a paper feed unit poised for bringing a document into the scanner. As shown in
FIG. 5
, one end of the paper feeding assembly
300
is lifted up through a tension spring
370
so that the roller
320
remains in suspension without touching any scan document
400
. When power to the automatic document feeder
100
is turned on, the paper feed unit
300
takes action. Driven by a driving device, the shaft
340
rotates (rotates in a clockwise direction in the figure) and drives the rollers
320
and
322
in the same direction rotation. Subjected to the driving force provided by the shaft
340
, the friction plate
350
also rotates. The rotation of the friction plate
350
causes both the friction plate
352
and the torsion spring
360
to turn due to friction. Since one end
362
of the torsion spring
360
is fastened to the body casing
310
, a torque is provided by the torsion spring
360
to turn the entire paper feed unit
300
relative to the central axis of the shaft
340
(clockwise rotation in the figure). Hence, the uplifting force provided by the spring
370
is canceled out.
FIG. 6
is a schematic side view showing the configuration of a paper feed unit
300
after lowering the roller
322
onto the document
400
. With the paper feed unit
300
lowered, documents
400
are transferred into the optical scanner
200
through the automatic document feeder
100
one by one.
FIG. 7
is a schematic side view showing the external profile of the friction plates
350
and
352
. As shown in
FIG. 7
, both friction plates
350
and
352
have a circular shape with a hollow tubular center. The tubular sleeve profile permits the friction plate
350
to slide into the shaft
340
while the tubular sleeve profile permits the friction plate
352
to slide into outer bossing of the friction plate
350
(that is, the friction plate
352
slides into the shaft
340
only indirectly). The frictional contact surfaces between the friction plates
350
and
352
include the vertical surfaces
3501
,
3521
along the radial direction and the circular surfaces
3502
,
3522
parallel to the axial direction.
When the friction plate
350
slides into the friction plate
352
, tolerance between the two has considerable effect on the ultimate area involved in frictional contact. In general, tolerance between axial diameter of the friction plate
350
and hole diameter of the friction plate
352
is rather loose due to the cost of producing a tight fit. A loose fitting between the friction plates
350
and
352
often leads to coupling problems such as the one shown in FIG.
8
.
FIG. 8
is a diagram of a portion of the paper feed unit showing the friction plate
352
having a slant face relative to the straight face of the friction plate
350
due to an unevenly distributed pressure exerted by the torsion spring
360
.
FIG. 9
is a magnified cross-sectional view of the friction plates
350
and
352
engaged directly and indirectly to the shaft
340
as shown in FIG.
8
.
FIG. 10
also shows one other form of distortion between the friction plates
352
and
350
due to the presence of a gap between the hole in the friction plate
352
and the axle in the friction plate
350
.
FIG. 11
is a magnified cross-sectional view of th
Chen Pi-Chun
Huang Yin-Chun
Tsuei Ji-Mei
Jianq Chyun IP Office
Joerger Kaitlin
UMAX Data Systems Inc.
Walsh Donald P.
LandOfFree
Friction plate coupling structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Friction plate coupling structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Friction plate coupling structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3044857