Abstract:
A trough device in a soldering furnace comprises a motor, a soldering pot, support device, a trough part and transmission device. The support device connects with a fixing base of the motor via a micro adjustment device and an inclinometer for adjusting an inclining angle of the soldering pot and informing the adjusted inclining angle. A guidance part with double layer structure is located at the soldering pot and can receive the solder oxide residue falling down from the circuit board or spattered out from the soldering pot to prevent the solder oxide residue from flowing back to the trough part. The transmission device further comprises a transmission shaft, a shaft hub, a fan blade part and fixing plate assembly. The shaft hub surrounds the transmission shaft with bearings being disposed between the shaft hub and the transmission shaft. The fixing plate assembly is arranged at the lower end of the shaft hub and engages with the soldering pot by way of screw threads. The transmission shaft, the shaft hub, the fan blade part, and the fixing plate assembly can be fixed coaxially with being firmly supported by the shaft hub. Hence, the transmission shaft can rotates more steadily and the component parts thereof can be free from being contaminated by the tin solder.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a trough device in a soldering furnace, and particularly to a trough device, which is disposed in a soldering furnace and is attached with a soldering pot in conjunction with a transmission device so as to enhance the soldering job on a circuit board.  
           [0003]    2. Description of Related Art  
           [0004]    Referring to FIGS.  1  to  3 , a trough device A in a conventional soldering furnace comprises a transmission shaft A 1 , a soldering pot A 2 , a screen plate A 3 , a guidance part A 4 , a fan blade part A 5 , a trough part A 6 , and a motor A 7 . The transmission device A 1  provides a support frame A 11  to hold the transmission shaft A 1  and the transmission shaft passes through the fan blade part A 5  to engage with the bottom of the soldering pot A 2  by way of a nut A 12 . A transmission belt A 71  is disposed between to connect with the transmission shaft A 1  and the motor A 7  so that the transmission shaft A 1  can be driven by the motor A 7 . The tin solder in the trough part A 6  is heated up by the heater A 61  and is melted into liquid tin solder. Then, the liquid tin solder is sent to the screen plate A 3  through the soldering pot A 2  by the traction of the fan blade part A 5  and reaches to the guidance part A 4 . Finally, the liquid tin solder overflows the guidance part A 4  to perform the soldering job on a circuit board B. The conventional device has the following shortcomings:  
           [0005]    1. The circuit board B moves forward with an inclining angle D of 3˜7° as shown in FIG. 3, however, the tin solder overflows the guidance part A 4  horizontally and only a small part of area on the circuit board B touches the tin solder such that it results in an uneven soldered surface on the circuit board B.  
           [0006]    2. Although the working table carrying the circuit board B can be adjusted to have a higher elevation for shortening the distance between the circuit board and the guidance part A 4 , it is required to consider if the working table van be kept flat after the working table being adjusted. An improper adjustment for the working table may cause an uneven soldered surface on the circuit board and it is easy to become short circuit. Further, it is much tedious if the working table is raised the height thereof.  
           [0007]    3. The fan blade part A 5  usually provides a high rotational speed and it is insufficient for the support frame A 1  with the nut A 12  to hold the transmission shaft A 1  and the fan blade part A 5 . Hence, the axis of the transmission shaft A 1  may become deviated and the fan blade part A 5  may become loosely after a period of running.  
           [0008]    4. The components of the transmission device are arranged to expose to the outside and the tin solder is sprayed with a very high speed so that it is easy for the tin solder to stay in the clearances between the components and the life span of components may be shortened.  
           [0009]    5. The transmission device is hard to be set up or detached so that it is not favorable for the maintenance work.  
         SUMMARY OF THE INVENTION  
         [0010]    A trough device in a soldering furnace according to the present invention comprises a motor, a soldering pot, support device, a trough part and transmission device. The support device connects with a fixing base of the motor via a micro adjustment device and an inclinometer for adjusting an inclining angle of the soldering pot and informing the adjusted inclining angle. A guidance part with double layer structure is located at the soldering pot and can receive the tin oxide residue falling down from the circuit board or spattered out from the soldering pot to prevent the oxide tin residue from flowing back to the trough part. The transmission device further comprises a transmission shaft, a shaft hub, a fan blade part and fixing plate assembly. The shaft hub surrounds the transmission shaft with bearings being disposed between the shaft hub and the transmission shaft. The fixing plate assembly is arranged at the lower end of the shaft hub and engages with the soldering pot by way of screw threads. The transmission shaft, the shaft hub, the fan blade part, and the fixing plate assembly can be fixed coaxially with being supported firmly by the shaft hub and the fixing plate assembly so that the transmission shaft can rotate more steadily and the components in the transmission device can be free from being contaminated by the tin solder.  
           [0011]    A primary object of the present invention provides a trough device in a soldering furnace, in which the soldering pot can be turned an inclining angle to the right and the reversed directions with a support device so that the timing of the tin solder overflowing the guidance part can be extended from the solder disengaging point of the circuit board to the solder wave. Hence, it is not possible for the pin legs on the circuit board to connect with each other so that it is unable to result in short circuit.  
           [0012]    Another object of the present invention provides a trough device in a soldering furnace, in which the guidance part thereof may have an output adjustable plate to adjust the amount of tin solder flowing out from the guidance part properly so as to expand the contact area of the circuit board more evenly.  
           [0013]    A further object of the present invention provides a trough device in a soldering furnace, in which a micro adjustment device and a inclinometer can indicate the inclining angle of the soldering pot automatically.  
           [0014]    A further object of the present invention provides a trough device in soldering furnace, in which the guidance part has a double layer structure to refrain the oxide tin solder from flowing back.  
           [0015]    A further object of the present invention provides a trough device soldering furnace, in which the transmission shaft is surrounded by a shaft hub and is fixed to a fixing plate assembly at the lower end thereof so that the transmission shaft can rotate more steadily with support of the shaft hub and the fixing plate assembly.  
           [0016]    A further object of the present invention provides a trough device in a soldering furnace, in which the transmission shaft is surrounded by a shaft hub to avoid the tin solder staining the transmission shaft and other components so as to prolong the life span of the trough device.  
           [0017]    A further object of present invention provides a trough device in the soldering furnace, which is simple for maintenance. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    The present invention can be more fully understood by reference to the following description and accompanying drawings, in which:  
         [0019]    [0019]FIG. 1 is an exploded perspective view of a conventional trough device in a soldering furnace;  
         [0020]    [0020]FIG. 2 is an assembled perspective view of the trough device shown in FIG. 1;  
         [0021]    [0021]FIG. 3 is a sectional view of a soldering pot in the conventional trough device illustrating a circuit board being delivered forward over the soldering pot;  
         [0022]    [0022]FIG. 4 is an assembled perspective view of a trough device in a soldering furnace according to the present invention;  
         [0023]    [0023]FIG. 5 is a disassembled perspective view of the trough device shown in FIG. 4;  
         [0024]    [0024]FIGS. 6 and 7 are sectional views of a soldering pot in the trough device in a soldering furnace according to the present invention illustrating two different operations of the soldering pot for a circuit board;  
         [0025]    [0025]FIG. 8 is an assembled perspective view of a trough device in a soldering furnace according to the present invention in a second embodiment thereof;  
         [0026]    [0026]FIG. 9 is a perspective view of a guidance part in the soldering pot of the second embodiment shown in FIG. 8;  
         [0027]    [0027]FIG. 10 is another perspective view of the guidance part shown in FIG. 8 projecting from another projection angle;  
         [0028]    [0028]FIG. 11 is a sectional view of the soldering pot in the second embodiment of the present invention shown in FIG. 8 illustrating the operation of a circuit board being soldered;  
         [0029]    [0029]FIG. 12 is an exploded perspective view of a micro adjustment device in the second embodiment shown in FIG. 8;  
         [0030]    [0030]FIG. 13 is a side view of the soldering furnace of the second embodiment of the present invention shown in FIG. 8 clearly showing the micro adjustable device thereof;  
         [0031]    [0031]FIG. 14 is a side view similar to FIG. 13 illustrating the micro adjustable device thereof having been adjusted;  
         [0032]    [0032]FIG. 15 is an exploded perspective view of the soldering pot with related driving parts in the soldering furnace according to the present invention in a third embodiment thereof;  
         [0033]    [0033]FIG. 16 is an assembled sectional view of the third embodiment shown in FIG. 15;  
         [0034]    [0034]FIG. 17 is an exploded perspective view of the soldering pot with related driving parts according to the present invention in a fourth embodiment thereof; and  
         [0035]    [0035]FIG. 18 is a sectional view illustrating the soldering pot with related driving parts in the soldering furnace of the fourth embodiment shown in FIG. 17 being assembled. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]    Referring to FIGS. 4 and 5, a trough device in a soldering furnace according to the present invention in a first embodiment thereof mainly comprises a motor  20 , a soldering pot  30 , two support devices  40   a ,  40   b , and a trough part  10 .  
         [0037]    The motor  20  is fixedly mounted in a fixing base  21  and drives a transmission shaft  23  with a fan blade part  24  attached to a lower end of the transmission shaft  23  via a transmission belt  22  such that the fan blade part  24  can rotate with the transmission shaft  23  as soon as the motor  20  starts to run.  
         [0038]    The soldering pot  30  extends upward a respective fixing arm  31  from two opposite short sides thereof with an opening being provided on the top thereof near one of the short sides for mounting a guidance part  32  and another opening  33  being provided on the top thereof near the other short side for receiving the fan blade part  24  such that the transmission shaft  23  can be fixed to the soldering pot  30  through the fan blade part  24 .  
         [0039]    Each of the support device  40   a ,  40   b  is composed of a support rod  41   a ,  41   b  and a holding block  42   a ,  42   b  respectively. The support rod  41   a , 41   b  has a fixed end  411   a ,  411   b  and a support section  412   a ,  412   b . The holding block  42   a ,  42   b  provides a locating hole  421   a ,  421   b  so that the support section  412   a ,  412   b  of the support rod  41   a ,  41   b  can pass through the locating hole respectively.  
         [0040]    The trough part  10  has two opposite transverse lateral walls and two opposite longitudinal lateral walls. The respective transverse wall at the upper edge thereof is attached with one of the holding block  42   a ,  42   b  respectively and the respective longitudinal lateral wall at the outer side thereof is mounted with heating pipes  11 . The support section  412   a  can be fixedly attached to a lateral side of the fixing base  21 . The fixing arms  31  on the soldering pot  30  can be fastened to the fixing ends  411   a ,  411   b  firmly by way of screw threads. Thus, the fixing base  21  of the motor  20  can rotate to incline a proper angle together with the support rods  41   a ,  41   b  and the soldering pot  30 .  
         [0041]    Referring to FIG. 6 in company with FIG. 4, the circuit board B, which is disposed at an inclining angle D of 3˜7° to the horizontal plan, is delivered forward during the soldering operation. In the meantime, as soon as the fixing base  21  of the motor  2  is turned to an inclining position, the soldering pot  30  with the guidance part  32  can be turned to the same inclining angle as the fixing base  21  does. Due to the tin solder overflowing the guidance device  32  being closer to the surface of the inclining circuit board B in addition to the feature of the tin solder being able to flow downward from a high elevation, the solder disengaging point of circuit board can be extended behind the solder wave during soldering. Thus, soldered spots between two pin legs on the circuit board are not possible to connect with each other and a short circuit can be avoided. In addition, while in operation, it does not need to use great effort for the present invention as the prior art does. Furthermore, the guidance part  32  can be provided with an output adjustable plate  321  and the output adjustable plate  321  can be adjusted to move upward or downward according to the inclining angle of the guidance part  32  such that the tin solder in the soldering pot  30  cannot overflow easily. Hence, a greater and more even soldering area on the circuit board can be obtained due to the disengaging point being extended behind the solder wave. In this way, the soldering effect and the soldering quality can be enhanced substantially.  
         [0042]    Referring to FIG. 7, it is possible to keep the guidance part  32  in a state of not being rotated an inclining angle during soldering and it is only necessary to move the output adjustable plate  321  upward. This is another way for the liquid tin solder to contact with a greater area of the circuit board B by way of the surface tension of the liquid tin solder as the dash line shown in FIG. 7. Hence, a greater and more even soldering area on the circuit also can be obtained under a condition of the disengaging point being extended behind the solder wave so as to enhance the soldering effect and the soldering quality.  
         [0043]    Referring to FIG. 8, a second embodiment of the present invention is illustrated. The parts such as the motor  20 , the soldering pot  30 , the support devices  40   a ,  40   b , the trough part  10  in the trough device of the present embodiment are identical with the first embodiment shown in FIGS. 4 and 5. The difference of the present embodiment from the first embodiment is in that a support section  412   a  on the support rod  41   a  of the support device  40   a  and the fixing base  21  of the motor  20  connect with a micro adjustment device  70  and the guidance part  80  is a double layer structure composed of an inner layer part  81  and an outer layer part  82 .  
         [0044]    Referring to FIGS.  9  to  11  in company with FIG. 8, the guidance part  80  is composed of an inner layer part  81  and an outer layer part  82  as the preceding description. The inner layer part  81  at a bottom thereof provides apertures  811  and at two opposite lateral sides thereof has an upper inward bend section  812  respectively with an opening top  813  disposed in between. The outer layer part  82  has a container shape with an open upper section and surrounds the inner layer part  81  with a close end  821  and an open end  822 .  
         [0045]    Referring to FIG. 11 again, the tin solder in the soldering pot  30  enters the inner layer part  81  through the apertures  811  and reaches to the circuit board B via the opening top  813  to perform the soldering operation. Because the tin solder sprays with an extremely high speed, the tin solder may more or less spatter outside the circuit board B and the guidance part  80  during soldering. The spattered out tin solder can be collected by the outer layer part  82  and the open end  822  thereof can connect with an external pipe passage (not shown) for discharging the collected tin oxide residue in the outer layer part  82 .  
         [0046]    Referring to FIG. 12 in company with FIG. 8 again, the micro adjustment device  70  comprises a main plate  71 , a screw rod  72  and an adjustable bolt  73 . The main plate  71  at a lateral side thereof is fixed to the support section  412   a  and at another lateral side thereof is fixed to the fixing base  21 . The screw rod  72  at an upper end thereof provides a joint  74  pivotally connected to the lower part of the main plate  71  with a pivot  741  and at the lower end thereof engages with the adjustable bolt  73 . The adjustable bolt  73  at the head part thereof keeps contact with a support plate  12  extending from the trough part  10  such that the support plate  12  is subjected to the total load of the motor  20  and the fixing base  21 . It is noted that the arrangement of screw rod  72  with the adjustable bolt  73  is not for a restriction so that any other type of arrangement, with which the screw rod  72  can pivotally engage with the main plate  71  and the adjustable bolt  73  can be fixed to or disposed next to the trough part  10  for the adjustable bolt  73  being able to rotate without moving upward or downward and driving the screw rod  72 , can be obtained.  
         [0047]    A graduation scale  751  is arranged on the main plate  71  and a locating slot  711  is disposed next to the graduation scale  751  with an indicating needle  752 . The indicating needle  752  is movably located at the locating slot  711  by way of a shaft  753  passing through the locating slot  711  and engaging with the trough part  10 . The graduation scale  751  and the indicating needle  752  constitute an inclinometer  75 .  
         [0048]    Referring to FIGS. 13 and 14, the screw rod  72  can move upward or downward as soon as the adjustable bolt  73  is turned such that the main plate  71  is pulled by the traction of the joint  74  to rotate around the axis of the support section  412   a  and adjust the inclining angle of the soldering pot  30 . Because the indicating needle  752  is fixedly attached to the trough part  10 , the graduation indicated by the indicating needle  752  can show the adjusted inclining angle of the soldering pot  30  automatically as soon as the main plate  71  is in a state of inclining.  
         [0049]    Referring to FIGS. 15 and 16, a transmission device in the trough device comprises a soldering pot  30 , a fan blade part  24 , a transmission shaft  90 , a shaft hub  96  and a fixing assembly. The fixing assembly is composed of an upper fixing plate  50 , a lower fixing plate  60 , a plurality of support posts  63 , and a stub shaft  64 .  
         [0050]    The soldering pot  30  is a hollow body composed of an upper cover  34  and a lower base  35  with an upper recess  341  being arranged at the lower side of the upper cover  34  and a lower recess  351  being arranged at the upper side of the lower base  35 .  
         [0051]    The fan blade part  24  is disposed in the space between the upper recess  341  and the lower recess  351 .  
         [0052]    The transmission shaft  91  at the lower end thereof tightly fits with the fan blade part  24  and at upper end thereof is attached with a transmission wheel  92  to join a belt  22  such that the transmission shaft  91  can be driven by way of the motor  20  (as shown in FIG. 5).  
         [0053]    The shaft hub  96  is arranged surround the transmission shaft  91  with at least a bearing  93  being disposed between the shaft hub  96  and the transmission shaft  91 . It can be seen in FIGS. 15 and 16 that two bearings  93  are provided and a sleeve  94  is located between the two bearings  93 . Further, a cover cap  95  is disposed between the shaft hub  96  and the transmission shaft  91  and is fastened to the upper end of the shaft hub  96 .  
         [0054]    The upper fixing plate  50  with a central threaded hole  54  is disposed at the lower threaded end  961  of the shaft hub  96  with a plurality of engaging holes  53  next to the periphery thereof for being fastened to the upper cover  34  of the soldering pot  30  by way of bolts  52 . Further, the shaft hub  96  can be fastened to the upper fixing plate  50  in a way of the lower threaded end  961  engaging with the internal screw threads  51  in the threaded hole  54 .  
         [0055]    The lower fixing plate  60  at the periphery thereof provides a plurality of threaded holes  61  attached with a central bushing  62 . It can be seen in FIG. 15 that the threaded holes  61  thereof are equally spaced apart circumferentially.  
         [0056]    Each of the support posts  63  at the middle section thereof has two flanges  631 ,  632  spacing apart with a distance and two end parts thereof are threaded ends  633 ,  634 . The threaded end  634  engages with the lower fixing plate  60  and the threaded end  633  engages with the lower base  35  of the soldering pot  30 .  
         [0057]    The stub shaft  64  is disposed in the busing  62  on the lower fixing plate  60  and the upper end of the stub shaft  64  has a threaded end  642  with an upper flange  641  for engaging with a threaded hole  911  at the lower end of the transmission shaft  91 . The stub shaft  64  at the lower end thereof has an inner threaded end  644  with a lower flange  643  so that a cylindrical hub  65  with a lower cap  66  can be attached to the stub shaft  64  against the lower flange  643  by way of a bolt  67  engaging with the inner threaded end  642  and the lower cap  66 .  
         [0058]    Referring to FIGS. 17 and 18, a further embodiment of the transmission device of the present invention is illustrated. The transmission device  90 A comprises a soldering pot  30 A, a fan blade part  24 , a transmission shaft  91 A, a shaft hub  96  and a fixing device composed of a fixing plate  50 A, a bushing  55 A, a sleeve  912 A, a washer  56 A, a nut  57 A.  
         [0059]    The soldering pot  30 A is a hollow body composed of an upper cover  34 A and a lower base  35  with a through opening  341 A,  351  being arranged at the upper cover  34 A and the lower base  35  respectively.  
         [0060]    The fan blade part  24  is disposed between the through openings  341 A,  351 .  
         [0061]    The transmission shaft  91 A at the lower end thereof tightly fits with the fan blade part  24  and at upper end thereof is fixedly attached with a transmission wheel  92  to join a belt  22  so that the transmission shaft  91 A can be driven with a motor (not shown).  
         [0062]    The shaft hub  96  is arranged to surround the transmission shaft  91 A with at least a bearing being disposed between the sleeve  96  and the transmission shaft  91 . It can be seen in FIGS. 17 and 18 that two bearings  93  are provided and a sleeve  94  is located between the two bearings  93 . Further, a cover cap  95  is disposed between the shaft hub  96  and the transmission shaft  91 A and is fastened to the shaft hub  96  at the upper end thereof.  
         [0063]    The fixing plate  50 A is disposed at the lower end of the shaft hub  96  with a central sink  54 A and a plurality of engaging holes  53 A are arranged on the fixing plate  50 A next to the periphery thereof. It can be seen in FIG. 17 that four engaging holes  53 A are provided at four corners of the fixing plate  50 A so that fasten the fixing plate  50 A can be fastened to the upper cover  34 A of the soldering pot  30 A by way of bolts  52 A through the engaging holes  53 A. The central sink  54 A provides inner screw threads  51 A to engage with outer screw threads  961  at the lower end of the shaft hub  96 . The fixing plate  50 A at the lower central part thereof extends downward a hub with retaining holes  59 A.  
         [0064]    The bushing  55 A is inserted into the sink  54 A in the fixing plate  50 A with engaging holes  551 A through the wall thereof to align with the retaining holes  59 A in the fixing plate  50 A so that the bushing  55 A can be fastened to the fixing plate  50 A by way of bolts  58 A passing through the engaging holes  551 A and the retaining holes.  
         [0065]    The bushing  912 A is attached to the lower end of the transmission shaft  91 A and loosely fits with the bushing  55 A in the fixing plate  50 A.  
         [0066]    The nut  57 A with the washer  56 A engages with the screw threads  911 A at lower end of the transmission shaft  91 A so that the transmission shaft  91 A can be in conjunction with the soldering pot  30 .  
         [0067]    It is appreciated from the foregoing that the advantages of the transmission device of the present invention can be summarized in the following with reference to FIGS. 16 and 18:  
         [0068]    1. The transmission wheel  31 ,  92 , the transmission shaft  91 ,  91 A and the fan blade part  24  can be driven via the belt  22  smoothly and the transmission shaft  91 ,  91 A can be tightly retained and supported due to the shaft hub  96  being mounted surrounding the transmission shaft  91 ,  91 A with the sleeve  94  and the bearing  93  being mounted between the shaft hub  96  and the transmission wheel  31 ,  92  so that the sway of the transmission device can be avoided substantially.  
         [0069]    2. The shaft hub  96  engages with the fixing plate  50 ,  50 A and the fixing plate  50 ,  50 A further engages with the upper cover  34 ,  34 A by way of the bolts  52 ,  52 A such that the transmission shaft  91 ,  91 A is surrounded by the shaft hub  96  so as to protect the transmission shaft  91 ,  91 A from being contaminated by the sprayed tin solder (not shown).  
         [0070]    3. Because the tin solder is drawn into the soldering pot  30 ,  30 A as soon as the fan blade part  24  is in a state of turning, the tin solder staining on the transmission shaft  91 ,  91 A or the stub shaft  64  can be cleaned up easily as soon as the fixing plate  60  and the stub shaft  64  or the nut  57 A and the washer  56 A are detached.  
         [0071]    While the invention has been described with reference to preferred embodiments thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention which is defined by the appended claims.