Abstract:
A continuous forming method and device for an H-shaped FRP member for forming semi-hardened preimpregnated members produced by impregnating thermosetting resin to carbon fiber or glass fiber and the like into a predetermined H-shape. The forming device comprises of a device for mounting a plural number of bobbins having strip-shaped preimpregnated material spooled thereto, providing tension when pulling the impregnated material out from the bobbin. The device the shapes the preimpregnated material to a predetermined H-shape that feeds release films from four sides of upper, lower, left and right. The device then provides heat and pressure to the preimpregnated material from said four sides with a heating furnace for after-curing the preimpregnated material. The device then hauls and holds the preimpregnated material for cutting the cured product.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a forming device of a preimpregnated material produced by impregnating thermosetting resin to carbon fiber or glass fiber and the like. 
     DESCRIPTION OF THE RELATED ART 
     A technique for utilizing preimpregnated material produced by impregnating thermosetting resin such as epoxy resin and phenolic resin to long fiber such as carbon fiber and glass fiber to form a product having the desired cross-sectional shape by heating and forming the material is known. Since carbon fiber and glass fiber have great strength, especially tensile strength, per unit weight, a composite material formed by laminating fiber material with the fibers oriented in vertical, horizontal and diagonal directions can be used to manufacture products having light weight and relatively high strength and elasticity. Therefore, the material is widely utilized in forming aircraft and other industrial products. 
     The material used for forming the desired shape can be manufactured by arranging carbon fiber or glass fiber impregnated with thermosetting resin in parallel orientation to form one layer, by using fabric produced from these fibers to form one layer, or by laminating a plural number of such layers, further positioning roving of these fibers between layers if necessary to produce the forming member. The forming method and forming device of this material includes feeding plural strip-shaped preimpregnated materials from bobbins, heating and pressurizing the material by heated upper and lower molds of a hot press device to form a predetermined cross-sectional shape, an then curing the formed product in a curing furnace and completing the product. During the above-mentioned forming steps, the product is continuously pulled (hauled) by a haulage device mounted to the downstream side in the forming device so as to convey the product in the forming device. 
     However, the problems of the conventional forming method and device explained above is that notable friction resistance is generated when pulling the formed product by the haulage device, causing abrasion such as cutting or curling of the fiber. Furthermore, since the hauling force of the haulage device is strong, it is difficult according to the conventional method and device to form a thin product. Therefore, in order to solve these problems, the present applicants proposed, in Japanese Patent Laid-Open Application No. 2-102029, a device for intermittently transmitting strip-shaped preimpregnated material while bending the material with a mold so as to form a channel-shaped cross section, and hot-pressing the material to form a product with the desired shape. The device enables to continuously form structural members having linear trajectory with L-shaped or U-shaped cross section. The forming device of this kind is also disclosed in the specification of U.S. Pat. No. 4,151,031. 
     SUMMARY OF THE INVENTION 
     The present invention provides a device for efficiently forming H-shaped members made of FRP with advanced performance that can be used for underfloor beam member or reinforcement of main and tail planes of an aircraft. 
     The continuous forming device of an H-shaped FRP member according to the present invention comprises a device for mounting a plural number of bobbins having strip-shaped preimpregnated material produced by impregnating thermosetting resin to carbon fiber or glass fiber and the like spooled thereto, a device for providing tension when pulling the preimpregnated material out from the bobbin, a device for shaping the preimpregnated member to a predetermined H-shape, a device for feeding release films from four (upper, lower, left and right) sides, a press device for providing heat and pressure to the preimpregnated member from four sides, a heating furnace for after-curing the preimpregnated member, a device for hauling and holding the preimpregnated member, and a device for cutting the cured product to predetermined lengths. 
     Further, the device for shaping the strip-shaped preimpregnated member provided from the bobbins to form a predetermined H-shape comprises a device for forming two creases to two sheets of preimpregnated material in the longitudinal direction, a device for bending the sheet at the creases to form an open-trapezoid-shaped cross section, and a device for forming a U-shaped cross section and further superposing two U-shaped preimpregnated members to form an H-shape. 
     Moreover, the haulage device is interlocked with upper, left and right molds of the press device so that the preimpregnated member is heated and pressed for a predetermined time before being hauled for a predetermined length, and the press device is equipped with means for controlling the sequence for opening and closing the upper, left and right molds. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the exterior of the H-shaped member; 
     FIG. 2 is a cross-sectional view of the H-shaped member; 
     FIG. 3 is an explanatory view showing the outline of the continuous forming device of the H-shaped member; 
     FIG. 4 is a perspective view showing the material feeding device in the continuous forming device of the H-shaped member; 
     FIG. 5 is an explanatory view showing the step for forming the material to the shape of an H; 
     FIG. 6 is an explanatory view of the crease forming device; 
     FIG. 7 is an explanatory view showing the open-trapezoid-shape forming device; 
     FIG. 8 is an explanatory view showing the U-shape forming device; 
     FIG. 9 is an explanatory view showing the mold structure of the hot press device; 
     FIG. 10 is an explanatory view showing the haulage device and the cutting device of the sheet material; and 
     FIG. 11 is a chart showing the sequence of operation of the present device. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 is a perspective view showing the appearance of the H-shaped member formed according to the present invention, and FIG. 2 is a cross-sectional view thereof. 
     The H-shaped member shown as a whole by reference number  1 , comprising both side walls  10 ,  10  and a rib  20  that connects the center area of the side walls, is manufactured by heat-forming a preimpregnated material, which is made by impregnating thermosetting resin to FRP (fiber reinforced plastics: plastic material reinforced with carbon fiber or glass fiber and the like). 
     The H-shaped member  1  is formed by laminating a plurality of preimpregnated members P 1 , P 2 , and a surface member P 3 . The preimpregnated member P 1  is formed for example by alternately laminating preimpregnated sheets, the orientation of the fiber in each sheet arranged at an angle of 45 degrees to the longitudinal direction of the member. The preimpregnated member P 2  is formed by laminating preimpregnated materials having fiber arranged in one direction. By selecting the orientation of the fiber appropriately, the H-shaped member can be formed to provide the most appropriate strength required for various applications. During the forming process, a release film F is superposed on the upper surface, the lower surface and both side surfaces of the member. 
     FIG. 3 shows an outline of the continuous forming device according to the present invention. 
     The forming device shown as a whole by reference number  100  is equipped with a sheet-type material supply device  200 , a forming device  300  for bending the sheets to form an H-shape, a hot press device  400 , an after-cure device  500  which is a heating furnace, a sheet clamping (holding) device  600 , and a sheet haulage device  700 . 
     An appropriate cutter not shown is equipped downstream from the sheet haulage device  700  for cutting the product to appropriate lengths. 
     FIG. 4 is a perspective view showing the details of the material supply device  200 . 
     The material supply device  200  comprises a spindle  220  mounted on a stand  210 , and a bobbin  230  is rotatably mounted thereto. A preimpregnated sheet  250  with a release film  240  laminated thereto is spooled onto the bobbin  230 . Since the preimpregnated sheet  250  is tacky, it is spooled together with a release film  240 , and the release film  240  is removed from the surface of the preimpregnated sheet  250  at the time the sheet is supplied to the forming device. 
     The release film  240  is removed and spooled by an appropriate reel device  245 . 
     Six bobbins  230  are shown according to the present invention, but the number of the bobbins should be selected appropriately according to the specification of the H-shaped member to be formed. Moreover, release films are provided to the upper and lower surfaces of the sheet material. 
     FIG. 5 shows devices for forming the provided preimpregnated sheet member  250  to the shape of an H, and to transmit the shaped member to a hot press and an after-cure device. 
     The device  300  for bending the sheet members  250  to form an H is equipped with a device  310  for providing creases to the sheet members  250 , an infrared heater  320 , a device  330  for bending the sheet members to form an open-trapezoid-shape, a device  340  for bending the sheet members  250  to form a U-shape, and a device  360  for laminating release films  260  to the side walls of the H-shaped sheet materials  250 . 
     The formed preimpregnated sheet material is heated and pressure-formed in a hot press device  400 , before being transmitted to an after-cure device  500 . 
     FIG. 6 shows a crease-forming device  310 , wherein two rolls  312  and  314  placed to face one another on a frame  311  is formed as a unit, and two units are equipped on the frame with one unit placed above the other. 
     The first roll  312  comprises protruded regions  313  having the shape of abacus beads, and the second roll  314  comprises groove regions  315  for receiving the protruded regions  313 . 
     When traveling between the rolls  312  and  314 , the sheet members  250  are provided with creases  250   a.    
     The sheet members  250  provided with creases  250   a  are then fed to the open-trapezoid-shape forming device  330 . 
     At this stage, the sheet members  250  travel through an infrared heater  320 , which provides appropriate flexibility to the sheet members. The infrared heater  320  is equipped with heater units  322  placed above and under the sheet members  250 . 
     The open-trapezoid-shape forming device  330  shown in FIG. 7 comprises a frame  331  supporting rolls  334  having horizontal rotation axes and rolls  332  having tilted rotation axes, for bending the sheet members  250  traveling therethrough to form an open-trapezoid shape with the creases  250   a  positioned inward. 
     The sheet materials  250  each bent to form an open-trapezoid shape is then conveyed to the U-shape forming device  340  shown in FIG.  8 . The U-shape forming device  340  comprises belts  343  rotatably supported by axes  342  perpendicularly mounted on a frame  341 , and rolls  344  rotatably supported by horizontal axes. 
     When the open-trapezoid shaped sheet members  250  conveyed to the device  340  travel between the belts and rolls, each member is bent into a U-shape, and the two U-shaped sheets  250  are mutually fixed in the inverse direction to form an H-shape. 
     Next, release films  260  are laminated on both side surfaces of the H-shaped member at the station  360  before it is conveyed to the hot press device  400 . 
     FIG. 9 is an explanatory view showing the mold structure of the hot press device  400 . 
     The hot press device  400  is equipped with a lower mold  410  and an actuator  422  for driving an upper mold  420  opposing to the lower mold  410 . On both side areas of the upper and lower molds are positioned side molds  430  that are driven by actuators  432 . 
     The after-cure device  500  is a heating furnace for heating the H-shaped and pressed preimpregated sheet member at a predetermined temperature for a predetermined time, in order to accelerate the thermosetting of the resin. 
     FIG. 10 is an explanatory view showing the clamp of the sheet material mounted near the output of the after cure device  500 , a haulage device, and a cutting device. 
     The H-shaped member  270 , in other words, the product that has completed the curing process by the after-cure device  500 , passes through the product clamping device  600  and the haulage device  700 . 
     The clamping device  600  is equipped with a clamping means  610  for gripping the product  270  with an actuator  620 , and while the haulage device  700  is not operated, the clamping means constantly holds the product  270 . Since the area near the bobbin feeding the preimpregnated sheet material  250  is provided with a driving force that constantly pulls the preimpregnated sheet  250  back toward the bobbin so that tension is constantly provided to the sheet material  250  during the forming process, the clamping means prevents the product from being pulled back toward the bobbin by the tension. 
     The haulage device  700  is equipped with a gripper  710  that grips the product  270  through the operation of the actuator  720 , and the device  700  is slidably supported by a linear guide  730 . 
     The cylinder  740  drives the piston rod  750 , and the piston rod  750  drives the feeding device toward the arrow A direction through a connecting unit  760 . By the operation of the haulage device  700 , the product  270  is hauled and conveyed intermittently. 
     The cutting device  800  comprises a rotary cutting blade  840  that is driven by a motor through a transmission  820 , and through the actuator  830 , the rotary cutting blade  840  descends and separates the product  270 . 
     When the product  270  formed into a strip-shape reaches a predetermined length, the cutting device  800  is activated and the product  270  is cut into predetermined sizes. 
     For example, by detecting the position of the front end of the product  270  using a proximity switch and the like for activating the cutting device, the separating of the products  270  can be performed automatically. 
     FIG. 11 is a drawing showing the operational sequence of the hot press device  400 , the clamping device  600 , and the feeding (haulage) device  700 . 
     The upper mold of the press is closed before the left and right side molds of the press are closed, and the product is held in this position for a predetermined time, thereby completing the hot press process. 
     During this time, the clamping device  610  of the product is closed, maintaining grip of the product. 
     After holding the product by closing the haulage device and the clamping device  710 , the cylinder  740  is driven to move the clamping device  710  so as to convey the product  270 . 
     Furthermore, the haulage device and the clamping device described in the above-mentioned preferred embodiment are merely one example of devices that can be used in the present invention, and any appropriate device for hauling and gripping the product, such as those using rollers or caterpillars, can also be used. 
     As explained, the present invention enables to form H-shaped members made of FRP continuously and automatically.