Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
1999-11-12
2002-10-15
Bollinger, David H. (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C271S121000, C271S256000, C198S781010
Reexamination Certificate
active
06464217
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a sheet or envelope feeder and, more specifically, to the feeding mechanism of a feeder.
BACKGROUND OF THE INVENTION
Sheet and envelope feeders are commonly used in an envelope insertion system where envelopes are fed, one at a time, into an envelope inserting station, and enclosure documents are released into a gathering device for collation before the enclosure documents are inserted into the envelope at the envelope inserting station. They are also used in many different types of printers, photo copiers, print presses, and so forth. In those feeders, the most commonly used feeding mechanism is a drive roller assembly having a plurality of rollers mounted on a common shaft to be driven by a motor for rotation.
A typical envelope printer
100
is shown in FIG.
1
. As shown, the printer
100
has a rack
102
for supporting a stack of envelopes
104
to be fed into the printing area
106
. The feeding mechanism of the printer
100
comprises a set of six (6) drive rollers
108
for moving the envelopes
104
, one at a time, into the printing area
106
. On top of each drive roller
108
is a separator
110
forming a separation gap
112
to admit one (1) envelope
104
at a time into the printing area
106
. The separation gap
112
is adjustable according to the thickness of the envelope
104
.
In a prior art drive roller assembly
120
, as shown in
FIG. 2
, the drive rollers
108
are fixedly mounted on a drive shaft
114
. The drive shaft
114
is operatively connected to a motor
116
for rotation. A torque limiting device
118
is mounted between the motor
116
and the drive shaft
114
to set a maximum torque such that when the tangential force
122
exerted on the periphery
124
of one or more of the rollers
108
exceeds the maximum torque, all the rollers
108
, along with the drive shaft
114
, are mechanically decoupled from the motor
116
. In order to accommodate envelopes having certain ranges of thickness, the maximum torque for a feeding mechanism in a printer is set to usually about 10 pounds. Accordingly, when the motor
116
is turning, the rollers
108
are stopped only when the tangential force
122
exceeds ten (10) pounds. If an operator accidentally inserts a finger into one of the separation gaps
112
, this would result in discomfort or even injury to the operator. In order to reduce this safety hazard, it would be necessary to substantially reduce the maximum torque. However, with the driving assembly
120
as shown, it would be impractical to reduce the maximum torque far beyond the ten (10) pound limit for this would adversely affect the feeding function of the feeding mechanism.
It is, therefore, desirable to provide a method and a device for reducing the maximum torque of the driving rollers without adversely affecting the feeding function of the drive roller assembly while greatly reducing the safety hazard to the operator.
SUMMARY OF THE INVENTION
The present invention provides a method and a device for reducing the maximum torque to the rollers in a feeder for feeding substantially flat items such as printed documents, envelopes, cardboards and so forth. While the maximum torque to the individual rollers of the feeder is substantially reduced so as to greatly reduce the safety hazard to the operator, the feeding function of the feeder is not adversely affected. The device for reducing maximum torque, according to the present invention, comprises a drive roller assembly which includes: a drive shaft having a longitudinal axis operatively connected to a driving device for rotation about the longitudinal axis; a plurality of rollers mounted on the drive shaft for motion; and a plurality of torque limiting devices, each separately engaged with a roller for mechanically coupling the roller to the drive shaft and setting a maximum torque to the roller so that the roller is driven along with the drive shaft when a tangential force exerted on the roller does not exceed the maximum torque and the roller is mechanically decoupled from the drive shaft when the tangential force exerted on the roller exceeds the maximum torque, while such decoupling is accomplished without affecting the motion of the other rollers.
Accordingly, the method for reducing the torque to the drive rollers mounted on a common drive shaft in a drive roller assembly, according to the present invention, comprises the step of engaging a separate torque limiting device to each roller for mechanically coupling the roller to the drive shaft and setting a maximum torque to the roller so that the roller is driven along with the drive shaft when the tangential force exerted on the roller does not exceed the maximum torque and the roller is mechanically decoupled from the drive shaft when the tangential force exerted on the roller exceeds the maximum torque. Because each roller has a separate torque limiting device for setting the maximum torque, a roller can be mechanically decoupled from the drive shaft without adversely affecting the motion of the other rollers.
In other words, the method and device for reducing the torque to the drive rollers mounted on a common drive shaft in a drive roller assembly, according to the present invention, replaces a single torque limiting device for the entire drive roller assembly with a plurality of torque limiting devices, one for each roller. With each roller having a separate torque limiting device, the rollers will share the torque required for the entire feeding mechanism to function properly. Therefore, the maximum torque set for each of the rollers is only a fraction of the maximum torque when a single torque limiting device is used for the entire drive roller assembly.
The method and device, according to the present invention, will become apparent upon reading the description taken in conjunction with
FIG. 3
to FIG.
8
.
REFERENCES:
patent: 2655374 (1953-10-01), Townsley
patent: 4709911 (1987-12-01), Saiki et al.
patent: 5172899 (1992-12-01), Tajima
Kulpa Walter J.
Pritchett Wayne W.
Sette Paul R.
Sloan, Jr. Richard A.
Bollinger David H.
Levitsky Paul A.
Melton Michael E.
Pitney Bowes Inc.
Reichman Ronald
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