Abstract:
The tension device comprises: a feeding unit for feeding a band-shaped metal plate to a press unit; and a holding unit for applying tension to the band-shaped metal plate. The feeding unit is constituted by a moving member and a feeding pin. The front end of the feeding pin has a slope face so as to engage with a collared through-hole of the band-shaped metal plate when the moving member moves in a feeding direction of the band-shaped metal plate and so as to disengage therefrom when the moving member stops and moves in the reverse direction. The holding unit has a holding member, which holds and applies prescribed tension to the band-shaped metal plate when the moving member stops and which releases the band-shaped metal plate when the moving member starts to move in the feeding direction.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a tension device and a heat exchange fin manufacturing machine, more precisely relates to a tension device, which comprises a feeding unit for intermittently feeding a band-shaped metal plate to a press unit so as to form collared through-holes therein and a holding unit for applying tension to a part of the band-shaped metal plate located between the feeding unit and the holding unit when the press unit stops feeding the band-shaped metal plate to the press unit, and a heat exchange fin manufacturing machine having the tension device. 
         [0002]    Heat exchange fins for air conditioners, etc. are manufactured by, for example, a heat exchange fin manufacturing machine shown in  FIG. 6 . Heat exchange fins are formed by processing a band-shaped metal plate  10 , which is composed of, for example, aluminum. The band-shaped metal plate  10  is extended from a coil  12 . The band-shaped metal plate  10  extended from the coil  12  is inserted into an oil unit  16  so as to apply machining oil to a surface thereof, and then the band-shaped metal plate  10  is fed to a press die  20  of a press unit  18 . 
         [0003]    Collared through-holes, which have collars of a prescribed height, are formed in the band-shaped metal plate  10 , by the press die  20 , and equally spaced in the longitudinal direction of the band-shaped metal plate  10 . 
         [0004]    The band-shaped metal plate  10 , in which the collared thorough-holes have been formed, is sent a prescribed distance in a prescribed direction, and then cut by a cutter  26  so as to form a heat exchange fin having a prescribed length. The heat exchange fin is accommodated in a stacking unit. 
         [0005]    In the press unit  18  shown in  FIG. 6 , a hitch feeder  29  intermittently feeds the band-shaped metal plate  10  including the collared through-holes in a prescribed direction (see, for example, Japanese Patent Gazette No. 2006-21876). 
         [0006]    The hitch feeder  29  has driving means shown in  FIG. 7 . In the driving means, a connection rod  32  is connected to an eccentric pin of a crank  30 , which synchronously rotates with the press unit  18 , and a first link  36 , which turns about a pin  34 , and a second link  42 , which is connected to a lever  40  turning about a shaft  38 , are connected to a pin  44  provided to a lower end of the connection rod  32 . A cylinder unit  37  is provided to the first link  36  so as to adjust a swing angle thereof. In the driving means shown in  FIG. 7 , by rotating the crank  30 , the connection rod  32  reciprocally turns the lever  40  by the first link  36  and the second link  42 . 
         [0007]    As shown in  FIG. 8 , a link  46  is connected to an upper end of the liver  40  so as to reciprocally move a moving member  50  along a guide  48 . 
         [0008]    As shown in  FIG. 9A , a feeding pin  52 , whose front end part has a slope face, is provided to the moving member  50 . The front end part of the feeding pin  52  is upwardly biased by a spring  56  and projected upward from an upper face of a reference plate, which is provided above the moving member  50 , via a slit  54  of the reference plate. 
         [0009]    As shown in  FIG. 9A , the front end part of the feeding pin  52 , which is projected upward from the upper face of the reference plate, is inserted into a collared through-hole  11  of the band-shaped metal plate  10 , which has been mounted on the reference plate. 
         [0010]    By moving the moving member  50  in a direction A (see  FIG. 9A ), the band-shaped metal plate  10  is moved in the direction A. 
         [0011]    On the other hand, when the moving member  50  is moved in the reverse direction or a direction B (see  FIG. 9B ), the slope face of the front end part of the feeding pin  52  contacts an inner edge of the collared through-hole  11  and is moved in the direction B. With this action, the feeding pin  52  is retracted into the moving member  50  against a biasing force of the spring  56 , which is applied to the feeding pin  52 . Therefore, when the moving member  50  is moved in the direction B, feeding the band-shaped metal plate  10  can be stopped and the band-shaped metal plate  10  can be intermittently fed in the direction A. 
         [0012]    In the feeding unit shown in  FIGS. 9A and 9B , the moving member can be synchronously moved with the press unit  18 , and a feeding speed of the band-shaped metal plate  10  can be easily changed on the basis of increasing and reducing a rotational speed of the press unit  18 . 
         [0013]    However, in the feeding unit shown in  FIGS. 9A and 9B , if a rotational speed of the press unit  18  is high, the band-shaped metal plate  10  will move beyond the front end part of the feeding pin  52 , which includes the slope face, when the movement of the moving member  50  in the direction of feeding the band-shaped metal plate  10  is stopped. Namely, the band-shaped metal plate  10  will be excessively sent. 
         [0014]    If the band-shaped metal plate  10  is excessively sent, the press unit  18  processes wrong parts of the band-shaped metal plate  10  so that many bad products will be produced. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention was conceived to solve the above described problems. 
         [0016]    An object of the present invention is to provide a tension device, which is capable of applying tension to a band-shaped metal plate when a feeding unit stops feeding the band-shaped metal plate so as not to excessively feed the band-shaped metal plate. 
         [0017]    Another object is to provide a heat exchange fin manufacturing machine including the tension device of the present invention. 
         [0018]    The inventors have studied to solve the problems. Thus, they provided means for holding the band-shaped metal plate  10  in the press die  20  of the press unit  18  so as to apply tension to the band-shaped metal plate  10  when the moving member  50  is stopped. 
         [0019]    However, the holding means must hold the band-shaped metal plate  10  before perfectly stopping the moving member  50  so as to apply prescribed tension to the band-shaped metal plate  10 . On the other hand, in the press unit  20  which is synchronized with the press unit  18 , if the holding member holds the band-shaped metal plate  10  before perfectly stopping the moving member  50 , a timing of releasing the band-shaped metal plate  10  will lag behind starting the moving member  50  to move in the feeding direction. With this action, a great force is applied to the collared through-hole, in which the feeding pin  52  has been inserted, and the collared through-hole will be deformed. Therefore, it is difficult for unskilled operators to adjust the timings of holding and releasing the band-shaped metal plate  10 . 
         [0020]    Further, a distance of excessively feeding the band-shaped metal plate  10  is varied according to the rotational speed of the press unit  18 . In case of changing the rotational speed of the press unit  18 , the timings of holding and releasing the band-shaped metal plate  10  must be readjusted. 
         [0021]    The inventors have further studied to invent a tension device, which is capable of easily adjusting the timings of holding and releasing the band-shaped metal plate so as to apply prescribed tension to the band-shaped metal plate even if the rotational speed of the press unit is changed. 
         [0022]    As a result, in case that the feeding unit stops feeding the band-shaped metal plate to the press unit, it is effective to separately provide a holding unit for holding the band-shaped metal plate and applying prescribed tension thereto from the press unit and adjust the timings of holding and releasing the band-shaped metal plate according to the rotational speed of the press unit. Then, they reached the present invention. 
         [0023]    To achieve the objects, the present invention has following structures. 
         [0024]    Namely, the tension device of the present invention comprises: 
         [0025]    a feeding unit for intermittently feeding a band-shaped metal plate to a press unit so as to form collared through-holes therein; and 
         [0026]    a holding unit for applying tension to a part of the band-shaped metal plate located between the feeding unit and the holding unit when the press unit stops feeding the band-shaped metal plate to the press unit, 
         [0027]    the feeding unit is constituted by a moving member, which is capable of reciprocally moving in the longitudinal direction of the band-shaped metal plate, and a feeding pin, whose front end is biased toward the band-shaped metal plate by a biasing member provided in the moving member, 
         [0028]    the front end of the feeding pin has a slope face so as to insert the front end of the feeding pin into the collared through-hole of the band-shaped metal plate and engage the same with an inner edge of the collared through-hole when the moving member moves in a feeding direction of the band-shaped metal plate and so as to disengage the front end of the feeding pin and exit the same from the collared through-hole when the moving member stops and moves in the reverse direction, and 
         [0029]    the holding unit has a holding member, which contacts and holds the band-shaped metal plate so as to apply prescribed tension to the band-shaped metal plate when the moving member stops and which releases the band-shaped metal plate when the moving member starts to move in the feeding direction of the band-shaped metal plate. 
         [0030]    And, the heat exchange fin manufacturing machine of the present invention comprises: 
         [0031]    a press unit for forming collared through-holes in a band-shaped metal plate and cutting the band-shaped metal plate to form heat exchange fins having a prescribed length; 
         [0032]    the tension device of the present invention; and 
         [0033]    a suction unit for feeding the heat exchange fins to a stacking unit. 
         [0034]    In the tension device, the holding unit may include: 
         [0035]    a cam member making the holding member contact the band-shaped metal plate to hold the band-shaped metal plate and making the holding member separate from the band-shaped metal plate to release the band-shaped metal plate; and 
         [0036]    means for synchronously driving the cam member with operation of the press unit. With this structure, the timings of holding and releasing the band-shaped metal plate can be easily changed by changing the shape of the cam member. 
         [0037]    In the tension device, the moving member may synchronously move with operation of the press unit, and 
         [0038]    the driving means of the holding unit may be a servo motor. With this structure, the tension device can correspond to a high speed operation of the press unit. 
         [0039]    In the tension device, the feeding unit may be provided on the exit side of the press unit, and 
         [0040]    the holding unit may be provided on the entrance side of the press unit. With this structure, prescribed tension can be easily applied to the band-shaped metal plate. 
         [0041]    In the tension device, a fibrous member may be provided on a contact face of the holding member, which contacts the band-shaped metal plate. With this structure, damaging the surface of the band-shaped metal plate, which contacts the holding member, can be prevented. 
         [0042]    In the tension device of the present invention, the holding unit, which holds the band-shaped metal plate and applies the prescribed tension thereto, is separated from the press unit. Therefore, the timings of holding and releasing the band-shaped metal plate can be suitably adjusted on the basis of the rotational speed of the press unit. 
         [0043]    With this structure, deformation of the collared through-hole, which is caused when releasing the band-shaped metal plate lags behind starting the moving member to move in the feeding direction, can be prevented. 
         [0044]    In case of changing rotational speed of the press unit, the timings of holding and releasing the band-shaped metal plate can be easily adjusted, so that the tension device can correspond to change of an operation speed of the press unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0045]    Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which: 
           [0046]      FIG. 1  is an explanation view of an embodiment of a heat exchange fin manufacturing machine of the present invention; 
           [0047]      FIG. 2A  is a partial front sectional view of a holding unit provided on the entrance side of a press unit shown in  FIG. 1 ; 
           [0048]      FIG. 2B  is a side sectional view thereof; 
           [0049]      FIGS. 3A and 3B  are explanation views showing action of the holding unit shown in  FIGS. 2A and 2B ; 
           [0050]      FIGS. 4A-4C  are explanation views showing a relationship between the action of the holding unit shown in  FIGS. 2A and 2B  and the action of the press unit; 
           [0051]      FIGS. 5A and 5B  are explanation views of another holding unit used in the present invention; 
           [0052]      FIG. 6  is a schematic view of the conventional heat exchange fin manufacturing machine; 
           [0053]      FIG. 7  is a schematic view of the driving means used in the press unit shown in  FIG. 6 ; 
           [0054]      FIG. 8  is a schematic view of the moving member driven by the driving means shown in  FIG. 7 ; and 
           [0055]      FIGS. 9A and 9B  are explanation views of the feeding unit used in the press unit shown in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0056]    Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0057]      FIG. 1  shows an embodiment of a heat exchange fin manufacturing machine of the present invention. In the heat exchange fin manufacturing machine, a band-shaped metal plate  10  is extended from a coil  12  and fed to a press unit  18  with adjusting tension, etc. applied to the band-shaped metal plate  10 . In the press unit  18 , a number of collared through-holes are formed in the band-shaped metal plate  10  by a pair of press dies. Then, the band-shaped metal plate  10  is cut, by a cutter  26  of the press unit  18 , to form a plurality of elongated fin pieces having a prescribed width. The elongated fin pieces are fed to a suction unit  14  in order. When the elongated fin piece is fed a prescribed length to the suction unit  14 , a cutter of the press unit  18  cuts the elongated fin piece to form a heat exchange fin having the prescribed length. The heat exchange fin is sucked and held by the suction unit  14  and fed to a stacking unit  28 . 
         [0058]    A hitch feeder  29 , which is the feeding unit shown in  FIGS. 7-9B , is provided on the exit side of the press unit  18  shown in  FIG. 1 . The hitch feeder  29  has been explained, so explanation will be omitted. 
         [0059]    A holding unit  60 , which holds the band-shaped metal plate  10  and applies tension thereto when the movement of the moving member  50  of the hitch feeder  29  (see  FIGS. 9A and 9B ) in the feeding direction is stopped, is provided on the entrance side of the press unit  18 . 
         [0060]    In the holding unit  60 , as shown in  FIGS. 2A and 2B , cam members  68  are attached to side plates  64 , which are vertically extended from a base  62  on which the band-shaped metal plate  10  is moved, and a rotary shaft  66 , whose one end is connected to a servo motor  72 , and stationary members  70  are spanned between the side plates  64 . The servo motor  72  is synchronized with rotation of the press unit  18 . 
         [0061]    The cam members  68  respectively contact wheel members  82 , which are respectively and rotatably attached to shafts  80 . Each of the shafts  80  is spanned between vertical members  78 , which are vertically provided on a holding member  76  capable of moving close to and away from the upper face of the base  62  on which the band-shaped metal plate  10  is moved. A contact face of the holding member  76 , which contacts the band-shaped metal plate  10 , is covered with a contact member  74  composed of a fibrous material, e.g., felt. By covering the contact face of the holding member  76  with the fibrous contact member  74 , the band-shaped metal plate  10  can be securely held, and damaging the surface of the band-shaped metal plate  10  can be prevented. 
         [0062]    As shown in  FIG. 2B , springs  84 , which bias the holding member  76  toward the upper face of the base  62 , are provided between the holding member  76  and the stationary members  70 . 
         [0063]    In the holding unit  60 , the rotary shaft  66  is rotated by the servo motor  72 , which is synchronized with the rotation of the press unit  18 , the holding member  76  connected to the wheel member  82  is lifted against elasticity of the springs  84  when the cam member  68  attached to the rotary shaft  66  reaches a position for upwardly moving the wheel member  82  as shown in  FIG. 3A , so that the band-shaped metal plate  10 , which has been clamped between the contact member  74  and the surface of the base  62 , is released. 
         [0064]    Further, the cam member  68  is moved from the state shown in  FIG. 3A , in which the wheel member  82  is lifted, to the state shown  3 B, in which the wheel member  82  is lowered. In this state, the holding member  76  connected to the wheel member  82  is moved downward by the elasticity of the springs  84 , and the band-shaped metal plate  10  is clamped between the contact member  74  and the surface of the base  62 . 
         [0065]    Timings of holding and releasing the band-shaped metal plate  10  can be adjusted by changing the shapes of the cam members  68 . 
         [0066]    In the press unit  18  shown in  FIG. 1 , predetermined tension is applied to the band-shaped metal plate  10  between the hitch feeder  29 , which is provided on the exit side, and the holding unit  60  shown in  FIGS. 2-3B . 
         [0067]    In  FIG. 4A , the press unit  18  applies the tension. As shown in  FIG. 4A , in the press unit  18 , the band-shaped metal plate  10  is pressed while an angle of a crank shaft (crank angle) of the press unit  18  is 90-270°. When the crank angle is 180°, the dies of the press unit  18  are closed. While performing the press work, the band-shaped metal plate  10  is stopped. When the crank angle is 0° the dies of the press unit  18  are opened. 
         [0068]    Preferably, the tension is applied to the band-shaped metal plate  10  without applying a feeding load before stopping the feeding action so as to apply the prescribed tension to the band-shaped metal plate  10  at the timing of stopping the band-shaped metal plate  10 . Thus, as shown in  FIG. 4A , the shape of the cam member  68  is formed such that the contact member  74  starts to contact the band-shaped metal plate  10  at the crank angle of 330° after starting to feed the band-shaped metal plate  10 , and that the band-shaped metal plate  10  is securely clamped between the contact member  74  and the surface of the base  62 , as shown in  FIG. 3B , at the timing of stopping the feeding action of the band-shaped metal plate  10 . 
         [0069]    In  FIG. 4A , when the cam member  68  is further rotated until reaching the crank angle of 130°, a clearance is formed between the contact member  74  and the band-shaped metal plate  10  mounted on the base  62  as shown in  FIG. 3A . 
         [0070]    As shown in  FIG. 4B , the contact member  74  may start to contact the band-shaped metal plate  10  when the crank angle is 300°, and the clearance may be formed between the contact member  74  and the band-shaped metal plate  10  mounted on the base  62  when the crank angle is 100°. 
         [0071]    In case that a holding member, which contacts and holds the band-shaped metal plate  10 , is provided in the press dies of the press unit  18 , the timing of holding the band-shaped metal plate  10  with the holding member and the timing of releasing the band-shaped metal plate  10  from the holding member cannot be independently adjusted from the rotation of the press unit  18 . In the press unit  18 , when the band-shaped metal plate  10  is released at the crank angle of 100° as shown in  FIG. 4C , the timing of starting to hold the ban-shaped metal plate  10 , at which the band-shaped metal plate  10  and the holding member are in contact with each other, is the crank angle of 260° which is the symmetrical angle of the crank angle of 100°. 
         [0072]    If the holding member contacts the band-shaped metal plate  10  before feeding the band-shaped metal plate  10  is started, an excessive load will be applied to the hitch feeder  29 , which acts as the feeding unit for feeding the band-shaped metal plate  10 . Further, the front end of the feeding pin  52  is inserted into the collared through-hole  11 , so the collared through-hole  11  will be deformed by the feeding pin  52 . 
         [0073]    In the holding unit  60  shown in  FIGS. 2A-3B , as shown in  FIGS. 4A and 4B , the holding member can start to contact the band-shaped metal plate  10  after starting to feed the band-shaped metal plate  10 , so that applying the excessive load to the hitch feeder  29  and the deformation of the collared through-hole  11  can be prevented. 
         [0074]    When feeding the band-shaped metal plate  10  is stopped, the holding unit  60  securely holds the band-shaped metal plate  10  and the prescribed tension can be applied to the band-shaped metal plate  10  at a position between the holding unit  60  and the hitch feeder  29 . Therefore, overfeeding or excessively feeding the band-shaped metal plate  10  can be prevented when feeding the band-shaped metal plate  10  is stopped, so that bad products, which are formed by overfeeding the band-shaped metal plate  10 , can be prevented. 
         [0075]    In the holding unit  60  shown in  FIGS. 2A-3B , the contact member  74  is biased toward the band-shaped metal plate  10  by the springs  84 , but another holding unit  60  shown in  FIGS. 5A and 5B  may be employed. 
         [0076]    In the holding unit  60  shown in  FIGS. 5A and 5B , the holding member  74 , in which the contact member  74  is attached to a bottom face, can be move to and away from the band-shaped metal plate  10  mounted on the upper face of the base  62 , which is biased by springs  86 . An eccentric cam  88  is rotatably provided between vertical members  78 , which are vertically extended from the holding member  76 . By rotating the eccentric cam  88  by the servo motor  72 , the holding unit  60  can release the band-shaped metal plate  10  (see  FIG. 5A ) and hold the same (see  FIG. 5B ). 
         [0077]    The invention may be embodied in other specific forms without departing from the spirit of essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.