AUTOMATIC SHEET FEEDER HAVING A FLEXIBLE ELEMENT ON ONE END OF THE PICK SHAFT
In an auto sheet feeder, a flexible element is disposed monolithically at one end of a pick shaft, the flexible element capable of moving close to or away from the center of a ratchet. A fluctuation section of the flexible element comprises a pawl for engaging with an inner tooth of the ratchet, allowing the ratchet for one-way rotating the pick shaft. A clutch pushes a pin of the flexible element and disengages the flexible element with the ratchet.
1. Field of the Invention
the present invention relates to an automatic sheet feeder, and more specifically, to an automatic sheet feeder having a flexible element on one end of the pick shaft.
2. Description of the Prior Art
Most image processing machines such as copiers, fax machines, printers, scanners, or multifunctional business machines are equipped with an auto sheet feeder (ASF) for feeding recording medium into the main section of the image processing machines. To lower the cost for manufacturing, the driving power generated by a motor for driving the ASF is also utilized to drive the paper conveying device. In the image processing machines the power is transmitted to each operating part through the gear set therein. A prior art ASF can handle one-way paper feeding as the motor drives the gear sets, which then drives a ratchet to rotate, and finally the ratchet, which connects with the pick shaft of the ASF, drives the pick shaft to rotate in one-way direction.
Since the ASF allows the papers to proceed in one direction and when the image processing machine does not feed the papers, the ASF (also known as the driven member) shall not be driven by the driving member (the ratchet and the gear set), the prior art ASF has an O-ring of particular appearance and a clutch member installed on one end of the pick shaft. Please refer to
However, in the ASF according to the prior art, the aforementioned one-way driving and disengagement are accomplished by the O-ring 140 and the restoring spring 150, the assembly of which is complicated as well: the restoring spring 150 must be installed with one end on the hook of the pick shaft 110 and a rotating axle 146 of the O-ring 140 installed on a rotating pivot of the pick shaft 110. Then a pair of tweezers is necessary for clipping the other end of the restoring spring 150, stretching the restoring spring 150, hooking the other end of the restoring spring 150 on the hook of the O-ring 140. As the O-ring 140 and the restoring spring 150 are kept in the position, the ratchet 120 is assembled then. The process of assembly according to the prior art is very complicated and the assembled elements are very easy to fall apart. Furthermore, the O-ring 140 and the restoring spring 150 raise the cost as well.
SUMMARY OF THE INVENTIONThe claimed invention provides an automatic sheet feeder having a flexible element on one end of the pick shaft. The automatic sheet feeder comprises a ratchet having a plurality of teeth and a pick shaft having a flexible element. The flexible element comprises a fixed section extending from the end of the pick shaft and a fluctuation section extending from the fixed section capable of moving close to or away from an axis. The fluctuation section comprises at least a pawl for engaging with the teeth of the ratchet, allowing the ratchet for rotating the pick shaft.
The claimed invention also provides an automatic sheet feeder having a flexible element on one end of the pick shaft. The automatic sheet feeder comprises a ratchet having a plurality of teeth and a pick shaft having a flexible element extending from the end of the pick shaft. The flexible element is capable of moving close to or away from an axis and comprises at least a pawl for engaging with the teeth of the ratchet, allowing the ratchet for rotating the pick shaft.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Please refer to
Please refer to
In
In order to lower the cost of the transmission power source and the transmission mechanism in the image processing machine, the ratchet 20 has to be disengaged with the pick shaft 10 when the ASF 1 does not feed the paper. Thus, the ratchet 20 does not drive the pick shaft 10 and cause error when the transmission motor keeps driving the gear set and the ratchet 20 for other movement such as paper conveying process or paper ejection process. Therefore, the ASF 1 further comprises a clutch 30 and the flexible element 40 further comprises a brake pin 44 extending from one end of the fluctuation section 42. Please refer to
In the exemplary embodiment according to the present invention, the curvilinear outline of the flexible element 40 (including the fixed section 41 and the fluctuation section 42) stretches by following close to the periphery of the ratchet 20, which makes the fluctuation section 42 performs only a small swing to disengage with the ratchet 20. On the other hand, the fixed section 41 is not a necessary part in another exemplary embodiment. The flexible element 40 extends directly from the first end of the pick shaft 10 and can swing close to or away from the shaft of the pick shaft 10 (or the center 24 or the ratchet 20).
The present invention utilizes a flexible element disposed monolithically at one end of a pick shaft, capable of moving close to or away from the center of a ratchet to achieve one-way auto sheet feeding in an image processing machine. A fluctuation section of the flexible element comprises a pawl for engaging with an inner tooth of the ratchet, allowing the ratchet for one-way rotating the pick shaft. A clutch pushes a pin of the flexible element and disengages the flexible element with the ratchet, which therefore simplifies the auto sheet feeder in the image processing machine by reducing the additional members like an O-ring and a restoring spring.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Claims
1. An automatic sheet feeder having a flexible element on one end of the pick shaft, comprising:
- a ratchet having a plurality of teeth; and
- a pick shaft having a flexible element, the flexible element comprising: a fixed section extending from the end of the pick shaft; and a fluctuation section extending from the fixed section capable of moving close to or away from an axis, the fluctuation section comprising at least a pawl for engaging with the teeth of the ratchet, allowing the ratchet for rotating the pick shaft.
2. The automatic sheet feeder of claim 1, further comprising a clutch, the flexible element further comprising a brake pin extending from one end of the fluctuation section for operating with the clutch.
3. The automatic sheet feeder of claim 1 wherein the fluctuation section extends from the fixed section capable of moving close to or away from the center of the ratchet.
4. The automatic sheet feeder of claim 1 wherein the plurality of teeth of the ratchet comprises a tooth-like incline and the pawl comprises a pawl-like incline, the extension lines of both the tooth-like incline and the pawl-like incline passing through the center of the ratchet.
5. The automatic sheet feeder of claim 1 wherein the fixed section and the fluctuation section extend from the end of the pick shaft by following the periphery of the ratchet.
6. An automatic sheet feeder having a flexible element on one end of the pick shaft, comprising:
- a ratchet having a plurality of teeth; and
- a pick shaft having a flexible element extending from the end of the pick shaft, the flexible element capable of moving close to or away from an axis and comprising at least a pawl for engaging with the teeth of the ratchet, allowing the ratchet for rotating the pick shaft.
7. The automatic sheet feeder of claim 6, further comprising a clutch, the flexible element further comprising a brake pin extending from one end of the flexible element for operating with the clutch.
8. The automatic sheet feeder of claim 6 wherein the flexible element extends from the end of the pick shaft capable of moving close to or away from the center of the ratchet.
9. The automatic sheet feeder of claim 6 wherein the plurality of teeth of the ratchet comprises a tooth-like incline and the pawl comprises a pawl-like incline, the extension lines of both the tooth-like incline and the pawl-like incline passing through the center of the ratchet.
10. The automatic sheet feeder of claim 6 wherein the flexible element extends from the end of the pick shaft by following the periphery of the ratchet.
Type: Application
Filed: Jan 14, 2008
Publication Date: Jul 17, 2008
Inventors: Chern-Shi Lam (Batu Pahat), Yen-Sung Hsieh (Taipei City)
Application Number: 12/013,479
International Classification: B65H 3/02 (20060101);