Patent Publication Number: US-2005115023-A1

Title: Tricolored handle structure for screwdriver

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a hand tool, and more particularly to a tricolored handle structure for screwdriver.  
      2. Description of the Prior Arts  
      Conventional handle structure for a screwdriver discloses a tool handle which is made by method of plastic ejection molding, wherein core handle is partially coated with plate-structured soft layer, so as to improve the grip. The other conventional handle structure for a screwdriver discloses a tool handle which is made by extrusion forming method, wherein the soft layer is coated on the core handle along the longitudinal direction. Another conventional handle structure for a screwdriver also discloses a tool handle made of buffering material, which is double colored (made by double ejection molding). Another conventional handle structure for a screwdriver discloses a tool handle which is made of two different materials.  
      The above-mentioned tool handles are made by two ejection molding processes, in first process the core handle is made and then soft layer is coated on the core handle in second process, and thus a double colored handle is formed. After that, a rod is inserted in the front of the handle. With this manner, the formed handle has only two colors, furthermore, it cannot be formed with trademark or patterns during the ejection molding process. Therefore, the production cost must be increased if print the trademark by mother methods after the handle is formed.  
      The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional handle structure for screwdriver.  
     SUMMARY OF THE INVENTION  
      The primary object of the present invention is to provide a tricolored handle structure for screwdriver. The tricolored handle structure is provided along the axial direction with a rod which extends outward from the handle, the handle has a hard-plastic made first core handle integrally melted with a hard-plastic made second core handle and then being coated with a soft third layer, the first core handle has at least a hard first pattern portion, the second core handle has at least a hard second pattern portion, wherein the first pattern portions and the pattern portion are not coated by third layer, the first pattern portion, the second pattern portion and the third layer are different colored and form a smooth surface of the handle.  
      The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which shows, for purpose of illustrations only, the preferred embodiment in accordance with the present invention.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a tricolored handle structure for screw driver with a rod in accordance with the present invention;  
       FIG. 2  is longitudinal cross sectional view of showing the condition of a tricolored handle structure for screw driver with a rod in accordance with the present invention in the third process ejection molding process;  
       FIG. 3  is longitudinal cross sectional view of showing the condition of a tricolored handle structure for screw driver with a rod in accordance with the present invention in the second process ejection molding process;  
       FIG. 4  is longitudinal cross sectional view of showing the condition of a tricolored handle structure for screw driver with a rod in accordance with the present invention in the first process ejection molding process;  
       FIG. 5  is an upside view of a tricolored handle structure for screw driver with a rod in accordance with the present invention in the first process ejection molding process.  
       FIG. 6  is an outside view of the final products of a tricolored handle structure for screwdriver in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to  FIGS. 1 and 2 , wherein a screwdriver with tricolored handle in accordance with the present invention is shown and generally comprised of a handle  2  and from which a rod  1  extends outward along the axial direction of the handle  2 . The principle characteristic of the screwdriver is that the handle  2  includes a hard-plastic made first core handle  21  integrally melted with a hard-plastic made second core handle  22  and then is coated with a soft third layer  23 . The first core handle  21  includes at least a rigid first pattern portion  212  with pattern on it, such as a trademark  210 , the second core handle  22  includes at least a rigid second pattern portion  225  with pattern printed on it, such as striate. And then the first and the second cores  21 ,  22 , except the first and the second pattern portions  212 ,  225 , are exteriorly coated with a third layer  23 . The first pattern portion  212 , the second pattern portion  225  and the third layer  23  form a tricolored smooth surface  231  of the handle  2 .  
      Referring to  FIGS. 4 and 5 , wherein a passage  20  is formed along the central axis of the first core handle  21  during the first process of ejection molding. The first core handle  21  is further provided with a protrusive first pattern portion  212  which will serve as a reference plane in next ejection molding process, on the first core handle  21  opposite to the first pattern portion  212  is formed with a sunken portion  213  which is defined with annular grooves, such that the first core handle  21  is possessed with rather even sectional area so as to prevent shrinkage distortion. The passage  20  serves to receive the rod  1  which serves as a reference plane in the next process. The molds in accordance with the present invention are operated in circular manner, thereby the parting lines of the respective molds of the present invention can be solved if the reference line of the passage  20  is well controlled. The first and the second core handles  21 ,  22  are made of PVC which is hard but not impact resistant and has a SHORE D hardness of 65 to 75. The first pattern portion  212  can be formed with trademark  210  (such as Y.C as shown in  FIG. 1 ), it is more easy to be made if the trademark  210  is flat-formed, but if it is curve-formed that the corresponding mould also should have the same curvature, so as to prevent plastic material intrusion in the next process. In order to be well integrated, the first and the second core handles  21 ,  22  are at least formed with a first annular groove  214  and a second annular groove  224  which to be filled up for the next process. The hard first core handle  21  also can be formed with a through hole  211  for reception of a tool rod.  
      Referring to  FIG. 3 , during the second process of ejection molding, the first core handle  21  formed in the first process is set in the second mold, the first pattern portion  212  and the passage  20  act as reference plane, and then the second mold is closed. There are spaces left in the mold for a second layer  223 , an end layer  222 , a hole layer  221  and the second pattern portion  225 . When different colored hard plastics are melted and ejected into the mould, it will flow into the spaces of the second mold except the first pattern portion  212 , and the sunken portion  213 , the annular grooves  214  will be filled up, in this way, the second core handle  22  is formed. In order to be well integrated in next process, the core handle  22  is additionally formed with at least a second annular groove  224  which is to be filled up in the next process. Now the second core handle  22  is fairly close to final product form, it only needs to be coated with a soft layer.  
      Referring again to  FIGS. 1 and 2 , or referring to  FIG. 6  during third process of ejection molding, the formed second core handle  22  is set in a third mold which is then closed with the first pattern portion  212 , the passage  20 , the end layer  222  as reference plane. There is space left for the third layer  23 . The first pattern portion  212  and the end layer  222  contact the surface of the third mold cavity. When different colored hard plastics are melted and ejected into the mould, it will flow into the space of the third mold except the first pattern portion  212 , the end layer  222  and the hole layer  221 , so as to form a soft third layer  23 , and meanwhile form the smooth surface  231  of the handle  2 , that is that almost there is no height difference among the first pattern portion  212 , the second pattern portion  225  and the third layer  23 , it can hardly be observed by eye. The soft third layer  23  is made of thermo-elastoplastic material which have SHORE A hardness of 35 to 75 and thickness 5 cm for improving grip.  
      While we have shown and described various embodiments 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.