Patent Publication Number: US-6701811-B1

Title: Screw feeding device

Description:
FIELD OF THE INVENTION 
     The present invention relates to a screw feeding device and more articularly, to a feeding device that has a compact size and includes an adjusting shaft for the safety board so that the device is easily to be assembled, operated and the depth of the screws can be controlled. 
     BACKGROUND OF THE INVENTION 
     A conventional screw feeding device known to the applicant is disclosed in U.S. Pat. No. 5,402,695 to Hornung and shown in FIGS. 1 to  4 . The device includes a guide body  10  and a barrel  11  which is connected to the guide body  10  by a spring and includes a shaft  12  pivotably received therein. An end of the shaft  12  has an axle  14  for connecting two gears  13  and the other end of the shaft  12  is movably received in a slot  101  in the guide body  10 . A positioning member  16  with a spring  15  are connected to the front end of the barrel  11 . The shaft  12  swings in the slot  102  so as to let the two gears  13  drive the belt  18  with the screws  17 . Notches  131  are defined in an inner side of each gear  13  and a one-direction valve  133  with a spring  132  are located between the two gears  13  so that the gears  13  can only rotate in one direction by the valve  133 . The belt  18  and the screws  17  move in the direction and the positioning member  16  positions the belt  18 . 
     Due to the movement of the two gears  13  is made by the swinging of the shaft  12 , and the two gears  13  have to cooperate with the valve  133  and the positioning member  16  so that the whole assembly is complicated and involves too many parts. It requires complicated manufacturing processes to make the notches  131  in the two gears  13  and to install the spring  132  in the one-direction valve  133 . The whole assembly occupies a lot of space. The belt  18  is not conveniently positioned because it is engaged with two gears  13 . Furthermore, the cooperation between the swinging of the gears  13  and the positioning member  16  cannot be satisfied by the users. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a screw feeding device that has a compact size and is easily to be assembled. A gear, a positioning gear and a hollow shaft are made into a one piece member and a one-direction bearing is received in the hollow shaft, a biasing plate is engaged with the positioning gear, thereby simplifying the structure of the device and may have a compact screw feeding device. 
     Another object of the present invention is that the screw feeding device may adjust the depth of the screws. An adjusting shaft is cooperated with a safety board, the adjusting shaft has an inclined surface which is engaged with a bead so as to be positioned precisely to achieve the purpose of micro-adjusting the depth of the screws. 
    
    
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a conventional screw feeding device; 
     FIG. 2 is a side view another status of the conventional screw feeding device; 
     FIG. 3 is a cross sectional view of the conventional screw feeding device; 
     FIG. 4 is another cross sectional view of the conventional screw feeding device; 
     FIG. 5 is an exploded view to show the screw feeding device of the present invention; 
     FIG. 6 is a perspective view to show the screw feeding device of the present invention; 
     FIG. 7 is a perspective view to show a part of the screw feeding device of the present invention; 
     FIG. 8 is a perspective view to show another side of the part of the screw feeding device of the present invention; 
     FIG. 9 is a side view to show a part of the screw feeding device of the present invention; 
     FIG. 10 is a side view to show another status of the part of the screw feeding device of the present invention; 
     FIGS. 11 to  13  show side views of various status of the part of the screw feeding device of the present invention; 
     FIG. 14 shows a side view of the device of the present invention; 
     FIG. 15 shows a deep depth of the screw is set to penetrate an object; 
     FIG. 16 6 hows a shallow depth of the screw is set to penetrate an object, and 
     FIG. 17 shows an enlarged view of the part of the screw feeding device of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 5 to  8  and  17 , the screw feeding device of the present invention comprises a guide frame  20 , a guide body  30 , a barrel  40 , a screw pushing unit  50  and an adjusting shaft  60 . A belt  71  to which a plurality of screws  70  is connected is operated by the device. 
     The guide frame  20  has a fixing block  21  on an end thereof and a fixing frame  23  is connected to the fixing block  21 . A screw driving member  22  driven by an electric tool extends through the fixing block  21 . A threaded hole  24  is defined in the predetermined position of the fixing block  21  and a recess  241  is defined beside the threaded hole  24 . A spring  242  and a bead  243  which is biased by the spring  242  are received in the recess  241 . 
     The guide body  30  is composed of two halves which are respectively connected to two insides of the guide frame  20 . A spring  31  and a spring frame  32  are retained in the guide body  30  which has an opening  33  located in correspondence with the guide frame  20 . A balance groove  34  and a curve groove  36  are respectively defined through the guide body  30 . A screw guide plate  38  and a handle  35  are connected to the guide body  30 . The screw guide plate  38  has a screw guide rail  381  defined therein which is located corresponding to the opening  33 . 
     The barrel  40  is composed of two halves and an outlet  41  is defined in a front end of the barrel  40 . A pin  42  extends through the balance groove  34  in the guide body  30  from a side of the barrel  40  so that the barrel  40  is reciprocatingly retained in the guide body  30  by the pin  42  and the spring  31 . An action space  43  and a feeding space  44  are defined in an inside of the front end of the barrel  40 . A positioning space  45  is located in correspondence with the action space  43  so that the action space  43 , the outlet  41  and the feeding space  44  are located in correspondence with each other. The feeding space  44  is located in correspondence with the screw guide rail  381  of the screw guide plate  38 . A bush  46  is received in the action space  43  and located corresponding to the screw driving member  22 . A safety board  47  is connected to a side of the outlet  41  and includes a plurality of positioning holes  471 . A positioning screw  48  extends through one of the positioning holes  471  and fixed to the side of the barrel  40 . A contact protrusion  49  is formed at a rear end of the safety board  47 . 
     The screw pushing unit  50  is received in the action space  43  and includes a gear  51 , a positioning gear  52 , a hollow shaft  53 , a one-direction bearing  54 , an axle  55  and a biasing plate  56 . The gear  51 , the positioning gear  52  and the hollow shaft  53  are made into a one-piece member and the teeth  511  on the positioning gear  51  are engaged with notches of the belt  71 . The positioning gear  52  includes recesses  521  and curve blocks  522 . The one-direction bearing  54  is inserted in the hollow shaft  53  and an end of the axle  55  is pivotably connected to the bearing  54 . The other end of the axle  55  is in an L shape and a guide screw  552  having a pulley  552  are connected to the L-shaped end. The guide screw  552  employs the pulley  551  to be retained in the curve groove  36 . The biasing plate  56  has a curve end  562  which is fixed in the positioning space  45  of the barrel  40  and the other end has a rounded end  561  which is in contact with the periphery of the positioning gear  52 . The rounded end  561  is engaged with the recess  521  after it overcomes the resistance from the inclined surface of the curve block  522 . 
     The adjusting shaft  60  is a circular block which has a serrated surface  61  at one end and the other end has a plurality of positioning notches  62 . A screw  63  extends through the adjusting shaft  60  and is engaged with the threaded hole  24  of the guide frame  20 . The positioning notches  62  contacting the adjusting shaft  60  is engaged with the bead  243  in the guide frame  20 . The serrated surface  61  is located to face the contact protrusion  49  of the safety board  47 . 
     Referring to FIGS. 9 to  13 , in FIG. 9, the screw  70  is not yet fed to the firing position and the user holds the handle  35 . The barrel  40  and the guide body  30  are in a relative retracted position, and the spring  31  is compressed. As shown in FIG. 10, the guide screw  552  of the axle  55  in the screw pushing unit  50  is moved by the curve groove  36  of the guide frame  20  to allow the axle  55  rotate the one-direction bearing  54  which rotate the hollow shaft  53 . The gear  51  is rotated and drives the belt  71  to feed the screws  70 . The gear  51  and the positioning gear  52  are completely rotated before the screws  70  are fired. The rounded end  561  of the biasing plate  56  will be engaged with the following recess  521  after the rounded end  561  overcomes the curve block  522  of the positioning gear  52 . This positions the gear  51  and the positioning gear  52 , in the meanwhile, a screw  70  is fed to the firing position. 
     Referring to FIGS. 11,  12 , after the screw  70  is positioned at the firing position, the screw driving member  22  rotates and pushes the screw  70  from the belt  71  and then is retracted in the guide body  30 . In the meanwhile, the barrel  40  is still retracted in the guide body  30 . 
     Referring to FIG. 13, after the handle  35  is released, the barrel  40  pops out from the guide body  30  by the spring  31  and the guide screw  552  of the of the axle  55  is driven by the curve groove  36  so as to rotate the bearing  54  in reverse which spins independently. In other words, the hollow shaft  53 , the gear  51  and the positioning gear  52  are not rotated. Besides, the positioning gear  52  is stopped by the rounded end  561  of the biasing plate  56 . Therefore, the positioning gear  52  is well positioned after the previous screw  70  is fired. The structure mentioned above simplifies the processes of assembly and the size of the whole assembly can be reduced. 
     It is to be noted that the structure of the one-piece member including the gear, the hollow shaft and the positioning gear, the one-direction bearing  54 , axle  55 , and the biasing plate  56  is so simple and can be made conveniently. The assembly of the one-direction bearing  54 , the axle  55  and the biasing plate  56  simplifies the assembly for the manufacturers and performs even better than the conventional ones. 
     The safety board  47  at a side of the outlet  41  has positioning holes  471  which keeps a fixed distance for the outlet  41  to the object to be screwed so that different lengths of screws  70  can be used in the device by positioning the positioning screw  48  in one of the positioning holes  471 . 
     As shown in FIGS. 14 to  16 , the serrated surface  61  of the adjusting shaft  60  contacts against the contact protrusion  49  of the safety board  47  so that the depth that the screw  70  penetrates into the object can be controlled. The positioning notches  62  on the other end of the adjusting shaft  60  is cooperated with the bead  243  so as to micro-adjust the position that the screws  70  penetrate in. 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.