Patent Publication Number: US-8985579-B1

Title: Paper feeding device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a paper feeding device, and more particularly to a paper feeding device capable of stabilizing paper feeding speeds and decreasing a manufacturing cost thereof. 
     2. The Related Art 
     Referring to  FIG. 8 , a conventional paper feeding device  100 ′ generally includes a pickup assembly  10 ′, a separation assembly  20 ′ disposed above the pickup assembly  10 ′, a first paper feeding assembly  30 ′ disposed behind the pickup assembly  10 ′, a second paper feeding assembly  40 ′ disposed above the first paper feeding assembly  30 ′, two ultrasonic sensors  50 ′ disposed oppositely and spaced from each other, a signal processor  60 ′ electrically connected between the two ultrasonic sensors  50 ′, a transmission assembly  70 ′ connected with the pickup assembly  10 ′ and the first paper feeding assembly  30 ′, and a motor  80 ′ connected with the transmission assembly  70 ′. 
     The paper feeding device  100 ′ defines a paper feeding channel  90 ′. The motor  80 ′ drives the pickup assembly  10 ′ and the first paper feeding assembly  30 ′ to rotate by virtue of the transmission assembly  70 ′ to make paper  200 ′ fed into the paper feeding channel  90 ′ of the paper feeding device  100 ′. When the paper  200 ′ is passed through an interval between the two ultrasonic sensors  50 ′, one ultrasonic sensor  50 ′ sends an ultrasonic signal, and the other ultrasonic sensor  50 ′ receives the ultrasonic signal. The signal processor  60 ′ analyzes a size of the ultrasonic signal for determining whether there are multiple pieces of paper  200 ′ fed into the paper feeding channel  90 ′ of the paper feeding device  100 ′. So the conventional paper feeding device  100 ′ determines an abnormal paper feeding condition. 
     However, the conventional paper feeding device  100 ′ determines the abnormal paper feeding condition by virtue of the two ultrasonic sensors  50 ′ and the signal processor  60 ′ that increases a manufacturing cost of the paper feeding device  100 ′. Moreover, the conventional paper feeding device  100 ′ has no way of detecting paper feeding speeds, so the paper feeding speeds are hardly stabilized. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a paper feeding device. The paper feeding device includes a lower housing, an upper housing, a pickup assembly, a separation assembly, a relay assembly, a paper friction mechanism, an elastic element, a paper speed detector, a first paper feeding assembly, a second paper feeding assembly, a transmission assembly, a motor and a control unit. The upper housing is disposed above the lower housing. The upper housing is spaced from the lower housing to form a paper feeding channel between the lower housing and the upper housing. The pickup assembly is disposed to the lower housing. The pickup assembly includes at least one pickup roller, and a top of the pickup roller projects beyond a top surface of the lower housing and being located in the paper feeding channel. The separation assembly is disposed to the upper housing and corresponding to a top of the pickup assembly. The separation assembly includes at least one separation roller, and a bottom of the separation roller projects under a bottom surface of the upper housing and is located in the paper feeding channel. The relay assembly is disposed to the lower housing, and is located to a downstream of the pickup assembly and the separation assembly which are partially located in the paper feeding channel. The relay assembly includes a relay roller, and a top of the relay roller projects beyond the top surface of the lower housing and being located in the paper feeding channel. The paper friction mechanism is slidably disposed to the upper housing and corresponding to a top of the relay assembly, and is located to the downstream of the pickup assembly and the separation assembly which are partially located in the paper feeding channel. The elastic element is elastically disposed between the upper housing and a top of the paper friction mechanism. The paper speed detector is fastened to the upper housing and is located in front of the paper friction mechanism. The first paper feeding assembly is disposed to the lower housing and is located to a downstream of the relay assembly and the paper friction mechanism which are partially located in the paper feeding channel. The first paper feeding assembly includes at least one feeding roller, and a top of the feeding roller projects beyond the top surface of the lower housing and being located in the paper feeding channel. The second paper feeding assembly is disposed to the upper housing and corresponding to a top of the first paper feeding assembly, and is located to the downstream of the relay assembly and the paper friction mechanism which are partially located in the paper feeding channel. The second paper feeding assembly includes at least one idle roller, and a bottom of the idle roller projects under the bottom surface of the upper housing and is located in the paper feeding channel. The transmission assembly is connected with the pickup assembly, the relay assembly and the first paper feeding assembly. The motor is connected with the transmission assembly. The control unit is connected with the paper speed detector and the motor. The control unit controls the paper speed detector to detect paper feeding speeds and the paper speed detector sends signals to the control unit for determining paper feeding conditions. The control unit controls the motor to rotate, and the motor drives the pickup assembly, the relay assembly and the first paper feeding assembly to rotate by virtue of the transmission assembly, and the first paper feeding assembly drives the second paper feeding assembly to rotate, the control unit is capable of adjusting rotating speeds of the motor, so that the paper feeding speeds are stabilized. 
     As described above, the paper feeding device determines the paper feeding conditions which include a normal paper feeding condition and an abnormal paper feeding condition by virtue of the control unit controlling the paper speed detector to detect the paper feeding speeds and the paper speed detector sending signals to the control unit so as to decrease a manufacturing cost of the paper feeding device. Furthermore, the control unit of the paper feeding device is capable of adjusting the rotating speeds of the motor, so that the paper feeding speeds are easily stabilized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description, with reference to the attached drawings, in which: 
         FIG. 1  is a perspective view of a paper feeding device in accordance with an embodiment of the present invention; 
         FIG. 2  is another perspective view of the paper feeding device of  FIG. 1 ; 
         FIG. 3  is an exploded view of the paper feeding device of  FIG. 1 ; 
         FIG. 4  is a schematic diagram of the paper feeding device of  FIG. 1 , wherein there is no paper fed into the paper feeding device; 
         FIG. 5  is a schematic diagram of the paper feeding device of  FIG. 1 , wherein there is single piece of paper fed into the paper feeding device; 
         FIG. 6  is a schematic diagram of the paper feeding device of  FIG. 1 , wherein there are multiple pieces of paper fed into the paper feeding device; 
         FIG. 7  is a schematic diagram of the paper feeding device of  FIG. 1 , wherein the paper is jammed; and 
         FIG. 8  is a perspective view of a paper feeding device in prior art. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIG. 1  to  FIG. 4 , a paper feeding device  100  in accordance with an embodiment of the present invention is shown. The paper feeding device  100  includes a lower housing  11 , an upper housing  12 , a pickup assembly  20 , a separation assembly  30 , a relay assembly  40 , a paper friction mechanism  50 , an elastic element  60 , a paper speed detector  70 , a first paper feeding assembly  81 , a second paper feeding assembly  82 , a transmission assembly  101 , a motor  102  and a control unit  103 . 
     Referring to  FIG. 3 , the lower housing  11  defines at least one first receiving groove  111 , at least one first locating groove  112  disposed behind the first receiving groove  111 , and a fastening groove  113  disposed between the first receiving groove  111  and the first locating groove  112 . In this embodiment, the lower housing  11  defines two first receiving grooves  111  transversely arranged and spaced from each other, and two first locating grooves  112  transversely arranged and spaced from each other. 
     Referring to  FIG. 1  to  FIG. 3 , the upper housing  12  is disposed above the lower housing  11 . The upper housing  12  is spaced from the lower housing  11  to form a paper feeding channel  90  between the lower housing  11  and the upper housing  12 . The upper housing  12  has a main board  121 , and a protruding lump  122  protruding upward from a top of the main board  121 . The upper housing  12  defines an accommodating groove  123  penetrating through a front and a rear of the protruding lump  122  and further penetrating downward through a bottom of the protruding lump  122  and the main board  121 . An inner surface of a top sidewall of the accommodating groove  123  defines a holding groove  124  communicating with the accommodating groove  123 . Two opposite sidewalls of the accommodating groove  123  define two guiding slots  125  vertically extending and transversely penetrating therethrough. The upper housing  12  defines at least one second receiving groove  126 , and at least one second locating groove  127  disposed behind the second receiving groove  126 . In this embodiment, the upper housing  12  defines two second receiving grooves  126  transversely arranged and spaced from each other, and two second locating grooves  127  transversely arranged and spaced from each other. The second receiving groove  126  is disposed in front of the protruding lump  122 , and the second locating groove  127  is disposed behind the protruding lump  122 . 
     Referring to  FIG. 1  and  FIG. 3 , the pickup assembly  20  is disposed to the lower housing  11 . The pickup assembly  20  includes a pickup shaft  21 , and at least one pickup roller  22  mounted to the pickup shaft  21 . In this embodiment, the pickup assembly  20  includes two pickup rollers  22  mounted to the pickup shaft  21 . The pickup shaft  21  is located under the lower housing  11 . The pickup roller  22  is received in the first receiving groove  111 , and a top of the pickup roller  22  projects beyond a top surface of the lower housing  11  and is located in the paper feeding channel  90 . 
     Referring to  FIG. 1  and  FIG. 3 , the separation assembly  30  is disposed to the upper housing  12  and corresponding to a top of the pickup assembly  20 . The separation assembly  30  includes a separation shaft  31 , and at least one separation roller  32  mounted to the separation shaft  31 . In this embodiment, the separation assembly  30  includes two separation rollers  32  mounted to the separation shaft  31 . The separation shaft  31  is disposed above the main board  121  of the upper housing  12 . The separation roller  32  is received in the second receiving groove  126 , and a bottom of the separation roller  32  projects under a bottom surface of the upper housing  12  and is located in the paper feeding channel  90 . 
     Referring to  FIG. 1  and  FIG. 3 , the relay assembly  40  is disposed to the lower housing  11 , and is located to a downstream of the pickup assembly  20  and the separation assembly  30  which are partially located in the paper feeding channel  90 . The relay assembly  40  includes a relay shaft  41 , and a relay roller  42  mounted to the relay shaft  41 . The relay shaft  41  is located under the lower housing  11 . The relay roller  42  is disposed to the fastening groove  113 , and a top of the relay roller  42  projects beyond the top surface of the lower housing  11  and is located in the paper feeding channel  90 . 
     Referring to  FIG. 1  to  FIG. 4 , the paper friction mechanism  50  is slidably disposed to the upper housing  12  and corresponding to a top of the relay assembly  40 , and is located to the downstream of the pickup assembly  20  and the separation assembly  30  which are partially located in the paper feeding channel  90 . The paper friction mechanism  50  includes a friction bracket  51  and two friction elements  52 . The two friction elements  52  are mounted to two opposite sides of a bottom of the friction bracket  51 . Each of the friction elements  52  shows an L shape. The friction bracket  51  has a base portion  511 . A top of the base portion  511  of the friction bracket  51  protrudes upward to form a buckling portion  512 . Two opposite sides of the base portion  511  protrude outward to form two guiding pillars  513 . The paper friction mechanism  50  is assembled to a rear of the accommodating groove  123 . The guiding pillars  513  are disposed to the guiding slots  125  and capable of sliding upward and downward along the guiding slots  125 . The elastic element  60  is elastically disposed between the upper housing  12  and a top of the paper friction mechanism  50 . Specifically, the elastic element  60  is elastically disposed between the inner surface of the top sidewall of the accommodating groove  123  and the top of the base portion  511  of the friction bracket  51  of the paper friction mechanism  50 . The paper friction mechanism  50  provides a positive force on the relay assembly  40  by virtue of the elastic element  60 . Specifically, one end of the elastic element  60  is held in the holding groove  124 , and the other end of the elastic element  60  is worn around the buckling portion  512 . In this embodiment, the elastic element  60  is a spring. 
     Referring to  FIG. 1  to  FIG. 4 , the paper speed detector  70  is fastened to the upper housing  12  and is located in front of the paper friction mechanism  50 . The paper speed detector  70  is assembled to a front of the accommodating groove  123  with a front end thereof being exposed outside from the front of the accommodating groove  123 . In this embodiment, the paper speed detector  70  is an optical sensor. 
     Referring to  FIG. 1  and  FIG. 3 , the first paper feeding assembly  81  is disposed to the lower housing  11  and is located to a downstream of the relay assembly  40  and the paper friction mechanism  50  which are partially located in the paper feeding channel  90 . The first paper feeding assembly  81  includes a feeding shaft  811 , and at least one feeding roller  812  mounted to the feeding shaft  811 . In this embodiment, the first paper feeding assembly  81  includes two feeding rollers  812  mounted to the feeding shaft  811 . The feeding shaft  811  is disposed under a bottom surface of the lower housing  11 . The feeding roller  812  is disposed to the first locating groove  112 , and a top of the feeding roller  812  projects beyond the top surface of the lower housing  11  and is located in the paper feeding channel  90 . 
     Referring to  FIG. 1  and  FIG. 3 , the second paper feeding assembly  82  is disposed to the upper housing  12  and corresponding to a top of the first paper feeding assembly  81 , and is located to the downstream of the relay assembly  40  and the paper friction mechanism  50  which are partially located in the paper feeding channel  90 . The second paper feeding assembly  82  includes at least one idle roller  821 . In this embodiment, the second paper feeding assembly  82  includes two idle rollers  821 . The idle roller  821  is disposed to the second locating groove  127 , and a bottom of the idle roller  821  projects under the bottom surface of the upper housing  12  and is located in the paper feeding channel  90 . 
     Referring to  FIG. 1  and  FIG. 4 , the transmission assembly  101  is connected with the pickup assembly  20 , the relay assembly  40  and the first paper feeding assembly  81 . The motor  102  is connected with the transmission assembly  101 . The control unit  103  is connected with the paper speed detector  70  and the motor  102 . The control unit  103  controls the paper speed detector  70  to detect paper feeding speeds and the paper speed detector  70  sends signals to the control unit  103  for determining paper feeding conditions. So, the paper feeding device  100  determines the paper feeding conditions which include a normal paper feeding condition and an abnormal paper feeding condition by virtue of the control unit  103  controlling the paper speed detector  70  to detect the paper feeding speeds and the paper speed detector  70  sending the signals to the control unit  103 . The control unit  103  controls the motor  102  to rotate, and the motor  102  drives the pickup assembly  20 , the relay assembly  40  and the first paper feeding assembly  81  to rotate by virtue of the transmission assembly  101 , and the first paper feeding assembly  81  drives the second paper feeding assembly  82  to rotate. The control unit  103  of the paper feeding device  100  is capable of controlling the paper speed detector  70  to detect the paper feeding speeds and adjusting rotating speeds of the motor  102 , so that the paper feeding speeds are easily stabilized. 
     Referring to  FIG. 1  to  FIG. 7 , an operating principle of the paper feeding device  100  is described as follows. Paper  200  is placed to a front of the paper feeding device  100 , and the paper  200  passes through the pickup assembly  20  and the separation assembly  30  to make the paper  200  feed into the paper feeding channel  90 . 
     When single piece of paper  200  is fed into the paper feeding channel  90  of the paper feeding device  100 , the motor  102  drives the relay assembly  40  to rotate clockwise by virtue of the transmission assembly  101 . Because a friction force between the relay assembly  40  and the single piece of paper  200  is larger than a friction force between the friction element  52  and the single piece of paper  200 , the single piece of paper  200  is brought along by the relay assembly  40  to be fed into the paper feeding device  100  normally, and the single piece of paper  200  can pass through a contact point of the friction element  52  of the paper friction mechanism  50  which contacts the relay assembly  40 , at the moment, the control unit  103  controls the paper speed detector  70  to detect the paper feeding speeds to be normal, and the paper speed detector  70  sends a signal to the control unit  103  for determining the normal paper feeding condition. The control unit  103  is capable of adjusting the rotating speeds of the motor  102  so as to stabilize the paper feeding speeds. 
     When multiple pieces of paper  200  are fed into the paper feeding channel  90  of the paper feeding device  100 , the motor  102  drives the relay assembly  40  to rotate clockwise by virtue of the transmission assembly  101 . Because a friction force between each two pieces of paper  200  is smaller than a friction force between the friction element  52  and the multiple pieces of paper  200 , and a friction force between the relay assembly  40  and the bottommost piece of paper  200  is larger than a friction force between the friction element  52  and the bottommost piece of paper  200 , only the bottommost piece of paper  200  is brought along by the relay assembly  40  to be fed into the paper feeding device  100  normally, and the bottommost piece of paper  200  can pass through the contact point of the friction element  52  of the paper friction mechanism  50  which contacts the relay assembly  40 . The pieces of paper  200  located on the bottommost piece of paper  200  are blocked by the paper friction mechanism  50  to slow down the paper feeding speed, at the moment, the control unit  103  controls the paper speed detector  70  to detect the paper feeding speeds to be sharply lowered, and the paper speed detector  70  sends another signal to the control unit  103  for determining the abnormal paper feeding condition. 
     The first paper feeding assembly  81  rotates to bring along the second paper feeding assembly  82  to rotate to further feed the paper  200 . 
     When the paper  200  passes through the relay assembly  40 , the paper  200  is jammed, the paper feeding speed is changed on account of the paper  200  bearing a blocking force, the control unit  103  controls the paper speed detector  70  to detect the paper feeding speed to be sharply lowered for determining the abnormal paper feeding condition, so that a detecting function of the paper  200  being jammed is realized. 
     As described above, the paper feeding device  100  determines the paper feeding conditions which include the normal paper feeding condition and the abnormal paper feeding condition by virtue of the control unit  103  controlling the paper speed detector  70  to detect the paper feeding speeds and the paper speed detector  70  sending signals to the control unit  103  so as to decrease a manufacturing cost of the paper feeding device  100 . Furthermore, the control unit  103  of the paper feeding device  100  is capable of adjusting the rotating speeds of the motor  102 , so that the paper feeding speeds are easily stabilized.