Abstract:
Disclosed is a hot air welder that consecutively joins sheets of synthetic resin material together to make a large-sized pavilion or a tent fabric, or welds and seals the seam lines of waterproof textiles or the like for waterproofing process. Instead of the conventional table-shaped body, there are provided an upright-standing drive body; hot-air welding means on an upper-side of the drive body; upper and lower drive rollers under the welding means, and wherein the welding work is performed by rotating and using alternatively the upper drive roller or the lower drive roller, according to the kind of fabrics to be welded and the work-substances. Therefore the heat welding and waterproofing process may be performed more easily for more various shaped work-substances, and that the troublesome work-substances such as sleeve or shoulder parts of waterproof clothes that have various positioned and shaped seam lines may be moved and rotated easily by the worker to be heat-welded and become waterproofed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a hot air welder that consecutively joins sheets of synthetic resin material together to make a large-sized pavilion or a tent fabric, or welds and seals the seam lines of waterproof textiles or the like for waterproofing process, and particularly to a hot air welder that operates upper and lower drive rollers having different fixed-positions and shapes according to the patterns and sizes or shapes of fabrics to be welded with hot air, and selects drive rollers in a suitable state for the work fabric, thereby making the welding process easier, greatly reducing the defective ratio of the welding process and increasing the productivity. 
     2. Description of the Related Art 
     As shown in FIG. 6, a conventional hot air welder includes upper and lower rollers on a table-shaped body  100 , and a separately-provided hot air generator  101  between the upper and lower rollers. When overlapped sheets of synthetic resin and a film supplied from a weld film portion  102  are introduced between the upper and lower rollers, the hot air generator  101  discharges a hot air thereto, so that the overlapped synthetic resin sheets are heat-welded by high temperature heat in combination with the compression operation of the upper and lower rollers. 
     Besides the welding process, the hot air welder is also used in a waterproofing process for seam lines of waterproof products, where a separately provided waterproof film is heat-welded for the seam lines of the waterproof products, thereby ensuring their complete waterproof protection. 
     Thus-welded sheet fabrics are used in a case where it is impossible to make a large-sized sheet fabric at a time, like the pavilion or a large-sized tent fabric. In addition, for clothes requiring the waterproof protection, like a raincoat or special working clothes, the synthetic resin film is heat-weld for the seam line of its fabric, thereby manufacturing waterproof fabrics having much improved waterproof ability. 
     However, in the above-mentioned conventional hot air welder, because the welding means is disposed on the table-shaped body, the table-shaped body serves as a barrier to the work and causes troubles in securing the workspace, making the work difficult. In addition, in a case of performing a waterproofing process for clothes such as waterproof clothes, it is very difficult or impossible to perform the waterproofing process for the seams of sleeve or shoulder parts. 
     Further, when various welding angles or positions are needed along the seam lines, as in the waterproofing work for the waterproof clothes having various to-be-welded parts, the conventional hot air welder cannot meet the requirement, failing to perform the waterproofing work for the seam lines, because the drive roller for conveying the introduced sheet is fastened on the table-shaped body. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to overcome the above-mentioned problems of the prior art, and the object is achieved by providing a hot air welder for synthetic resin wherein, instead of the conventional table-shaped body, there are provided an upright-standing drive body; hot-air welding means on an upper-side of the drive body; upper and lower drive rollers under the welding means, and wherein the welding work is performed by rotating and using alternatively the upper drive roller or the lower drive roller, according to the kind of fabrics to be welded and the work-substances, so that the heat welding and waterproofing process may be performed more easily for more various shaped work-substances, and that the troublesome work-substances such as sleeve or shoulder parts of waterproof clothes that have various positioned and shaped seam lines may be moved and rotated easily by the worker to be heat-welded and become waterproofed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an entire view showing a hot air welder according to the present invention. 
     FIG. 2 is a perspective view showing the main part of the hot air welder according to the present invention. 
     FIGS. 3 a  and  3   b  are front views of the hot air welder according to the present invention when upper and lower drive rollers are moved upward, respectively. 
     FIGS. 4 a  and  4   b  are rear views of the drive portion of the hot air welder according to the present invention, and each shows its drive state when the upper and lower drive rollers are loaded, respectively. 
     FIGS. 5 a  and  5   b  show examples of the welding work when using the upper and lower drive rollers, respectively. 
     FIG. 6 is an entire perspective view showing the conventional hot air welder. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described in more detail referring to the drawings. 
     FIG. 1 is an entire view of a hot air welder according to the present invention, and FIG. 2 is a detailed perspective view of the main part of the hot air welder. 
     As shown in the figures, the hot air welder includes welding means  10  that comprises a waterproof film supply roller  1 , a hot air generator  2  and an upper roller  3 . 
     An upright case-shaped drive body  12  is provided on one end of a support base  11 . 
     The welding means  10  is disposed on an upper end of the drive body  12 . Under the welding means  10 , there is provided an upper drive roller  22  for circumferential-directed welding process that is rotated by a connecting belt  29  included in a connecting rod  21  and a support arm  20 . 
     Under the upper drive roller  22 , there is provided a lower drive roller  33  for longitudinal-directed welding process that is rotated by connecting belts  32  and  32 ′ included in a plurality of bent arms  31  and  31 ′ and a connecting rod  30 . 
     As shown in FIGS. 4 a  and  4   b , the support arm  20  is connected to a rotation lever  24  provided on a rotation shaft  23  included in the drive body  12 ; one end of the rotation lever  24  is connected to a cylinder shaft  26  of a cylinder  25  rotatably fixed to the drive body  12 ; a gear  27  is provided on the other end of the rotation lever  24 ; and the rotation shaft  23  is connected to the gear  27  through a chain  28 . 
     The connecting rod  30  is connected to a bent lever  35  whose one end is connected to a rotation shaft  34  included in the drive body  12 ; the other end of the bent lever  35  is connected to a cylinder shaft  37  of a cylinder  36  rotatably fixed to the drive body  12 ; a connecting plate  39  having a gear  38  is coupled to the rotation shaft  34 ; and the rotation shaft  34  is connected to the gear  38  through a chain  40 . 
     A motor  42  for rotating a chain  41  and a gear  43  formed on one end of the chain  41  are disposed on the internal upper portion of the drive body  12 . The gear  43  is engaged with both the gear  38  of the bent lever  35  and the gear  27  of the rotation lever  24 , respectively, as shown in FIGS. 4 a  and  4   b.    
     In addition, as shown in FIG. 2, a pedestal  51  including a support roller  50  on one end thereof is rotatably disposed on one internal side of the support base  11 . One end of a rotation shaft  52  is pivotly connected to a fixed end of the pedestal  51 , and the other end is connected to a cylinder shaft  54  of a cylinder  53  fixed to one side of the support base  11 , so that the pedestal  51  can be rotated by the piston movement of the cylinder shaft  54 . 
     A more detailed description will now be made of the operation of the hot air welder according to the present invention, referring to the attached drawings. 
     The hot air welder for synthetic resin selects alternatively the upper drive roller  22  or the lower drive roller  33  to be brought into contact with the upper roller  3  disposed on the welding means, based on the shape of the fabric subject to the welding or waterproofing process. 
     As shown in FIG. 3 a , in a state where the upper drive roller  22  has been rotated upward to be in contact with the upper roller  3  of the welding means  10 , the upper roller  3  and the upper drive roller  22  press together and weld a not-shown fabric introduced from the upstream side. 
     In this case, together with the fabric, a not-shown waterproof film supplied from the waterproof film supply roller  1  above the welding means  10  is introduced between the upper roller  3  and the upper drive roller  22 , thereby welding the seam of the fabric, or separated and overlapped fabrics. 
     In addition, in a state as shown in FIG. 3 b  where, with the upper drive roller  22  being rotated downward, the lower drive roller  33  has been rotated upward to be in contact with the upper roller  3  of the welding means  10 , the upper roller  3  and the lower drive roller  33  perform various welding and waterproofing processes as described above referring to FIG. 3 a.    
     Such rotation movements of the upper and lower drive rollers  22  and  33  are made by a plurality of cylinders included in the drive body  12 . 
     In more detail, the rotation lever  24  coupled to the support arm  20  of the upper drive roller  22  of FIG. 2 is rotated, as shown in FIG. 4 a , by the piston movement of the cylinder shaft  26  of the cylinder  25  that is coupled to the drive body  12 , thereby rotating the upper drive roller  22 . 
     As shown in FIG. 4 a , when the cylinder shaft  26  is fully inserted in the cylinder  25 , the rotation lever  24  is in clockwise-rotated position, and the gear  27  coupled to one end of the rotation lever  24  is engaged with the gear  43  whose rotation is made by the motor  42  and the chain  41 . That is, when the support arm  20  is brought into the clockwise-rotated slate by the operation of the cylinder  25 , the gear  27  is engaged with the gear  43 , and, in addition, the chain  28  is rotated to rotate the central rotation shaft  23  of the rotation lever  24 . When the central rotation shaft  23  is rotated by the chain  28 , the upper drive roller  22  is rotated by the connecting belt  29  included in the support arm  20 . 
     Thus, being introduced between the upper drive roller  22  and the upper roller  3  of the welding means  10 , the fabric and the waterproof film are pressed and heat-welded by the hot air supplied from the hot air generator  2 . 
     In addition, the selection of the kind of the drive roller is determined according to the characteristics of the fabric and the waterproof product. When the lower drive roller  33  is selected, as shown in FIG. 4 b , the support arm  20  is rotated to move the upper drive roller  22  down, and the connecting rod  30  is rotated to move the lower drive roller  33  up. 
     In more detail, in a case where there is a need to use the lower drive roller  33 , the cylinder shaft  26  is extracted from the cylinder  25 , so that the rotation lever  24  fixed to one end of the cylinder shaft  26  rotates in counterclockwise direction. Thereby, the gear  27  disposed on the rotation lever  24  is separated from the gear  43  that is rotated by the motor  42 . 
     In addition, in a state where the upper drive roller  22  is completely moved down by the rotation of the rotation lever  24  to a predetermined rotation angle, when the cylinder  37  is inserted into the cylinder  36 , rotating the bent lever  35  in clockwise direction, the bent arms  31  and  31 ′ and the connecting rod  30  connected to the bent lever  35  as shown in FIG. 3 b  are all rotated, moving the lower drive roller  33  up. Thereby, the gear  38  disposed on the one end of the connecting plate  39  provided separately from the bent lever  35  becomes engaged with the gear  43  of the motor  42 , transferring the drive power to the lower drive roller  33 . 
     That is, the chain  41  is rotated by the rotation of the motor  42 , thereby rotating the gear  43 , and the gear  38  of the connecting plate  39  is rotated in combination with the rotation of the gear  43 . Thereby, the rotation shaft  34  connected to the connecting belts  32  and  32 ′ included in the bent arms  31  and  31 ′ is rotated by the chain of the connecting plate  39  connected to the gear  38 , consequently rotating the lower drive roller  33 . 
     Thus, with the fabric and the waterproof product being introduced, their welding and waterproofing processes are performed and, at the same time, the fabric moves on by the rotation movement of the lower drive roller  33 , thereby achieving the automatic work. 
     The upper and lower drive rollers  22  and  33  handle different kinds of the introduced waterproof product and fabric, according to their handling positions. 
     When the welding and waterproofing processes are performed for a ring-shaped one as shown in FIG. 5 a , that is, in a case where there is a need to perform the welding process in the circumferential direction, like the sleeve part of the waterproof product, the upper drive roller  22  for circumferential-directed welding process, attached to the end of the protruded connecting rod  21 , is moved up thereby making it possible to perform the welding process more easily. 
     When the welding and waterproofing processes are performed in the longitudinal direction for tube-shaped clothes and fabric as shown in FIG. 5 b , the lower drive roller  33  for longitudinal-directed welding process is moved up, making it possible to perform the work continuously in the longitudinal direction. 
     This method is very advantageous in the waterproofing process for the shoulder or arm parts of waterproof clothes. 
     Meanwhile, because the lower drive roller  33  is supported by a plurality of bent arms  31  and  31 ′ differently from the upper drive roller  22 , drooping of the lower drive roller  33  is caused by its own weight. For this reason, simultaneously with the upward movement of the lower drive roller  33 , the cylinder shaft  54  disposed in the lower part of the drive body  12  is extracted from the cylinder  53 , rotating the rotation shaft  52  fixed to the end of the cylinder shaft  54 . This rotation of the rotation shaft  52  allows the pedestal  51  fixed to the other end of the cylinder shaft  54  to be stood upright. 
     The upright-standing pedestal  51  permits the bent arm  31  of the lower drive roller  33  to be put on the upper portion of the support roller  50  attached to one end of the pedestal  51 . Therefore, the bent arms  31  and  31 ′ including the lower drive roller  33  are supported by the upright-standing pedestal  51 . This allows securing more stable position of the lower drive roller  33  and also avoiding the position change or the falling of the lower drive roller  33  during the work that are caused by both the pressure of the worker and the weight of the fabric. 
     The above-mentioned hot air welder for synthetic resin according to the present invention has advantages that the heat welding and waterproofing process may be performed more easily for more various shaped work-substances, and that the troublesome work-substances such as sleeve or shoulder parts of waterproof clothes that have various positioned and shaped seam lines may be moved and rotated easily by the worker to be heat-welded and become waterproofed. 
     Although preferred embodiments of the present invention have been described, it is to be understood that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention.