Patent Publication Number: US-9895584-B1

Title: Composite material integrally forged iron head of a golf club

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an iron head of a golf club, especially to a composite material integrally forged iron head of a golf club. 
     2. Description of Related Art 
     A conventional iron golf club head is mostly manufactured by forging or casting with one single steel material. Because the material properties lack diversity, the strike performance of the iron golf club head is limited. Therefore, to enhance the strike performance, the iron golf club head must be lightweight and large in volume, so a weight part is installed in the iron golf club head to adjust the density and to increase the properties of the iron golf club head. 
     The conventional iron golf club heads has several types as follows: 
     1. Integrated Forged or Cast Iron Head 
     The materials of the iron golf club head include carbon steel, stainless steel or titanium, which are applied in an integrated forging or casting process. The density of the carbon steel is around 7.7 g/cc to 7.9 g/cc, and the density of the stainless steel is around 7.6 g/cc to 7.8 g/cc. The densities of both of the steel materials are heavy such that it is hard to reduce the weight and increase the volume of the iron golf club head in manufacture. The titanium material can be made of a large-volume iron golf club head, and the density of the titanium material is around 4.5 g/cc. However, the material and manufacturing of a titanium iron golf club head costs too high and can hardly gain the market acceptance. 
     2. Composite Aluminum Alloy Material Forged Iron Head 
     The aluminum composite iron golf club head includes a head body and a weight part. The head body is made of carbon steel or stainless steel and is combined with the weight part made of aluminum alloy by forging. The aluminum alloy material has a density of around 2.5 g/cc and has a suitable weight as an ideal material for producing the iron golf club head. In a forging process, the forging temperature is usually from 700 to 1200° C. and the melting point of the aluminum alloy material is only from 650 to 680° C., so the structure of the weight part will be damaged and will not be combined with the head body tightly by forging. The strike performance of the golf iron head is also influenced by the manufacturing process. 
     3. Composite Titanium Alloy Material Forged Iron Head 
     The titanium composite iron golf club head includes a head body and a weight part. The head body is made of carbon steel or stainless steel and is combined with the weight part made of titanium alloy by forging. The weight part has a density of around 4.5 g/cc of with good physical properties, but titanium alloy costs higher than other materials and the manufacturing process is complicated, making the price of the iron head product beyond market acceptance. Also, the density of the titanium alloy is slightly less than the density of carbon steel or stainless steel, and thus the weight of the iron golf club head cannot be decreased and the volume of the iron golf club head cannot be increased substantially. 
     To overcome the shortcomings of the conventional manufacture method, the present invention provides a manufacturing method of an iron golf club head to mitigate or obviate the aforementioned problems. 
     SUMMARY OF THE INVENTION 
     The main objective of the present invention is to provide a composite material integrally forged iron head of a golf club. 
     The composite material integrally forged iron golf club head includes a head body, a weight part and a cover. The head body has an engaging recess formed inside. The weight part is mounted in the engaging recess and the material of the weight part is composite ceramics and has a density of 1.3 to 3.5 g/cc. The cover is welded on the engaging recess of the head body, and the weight part is sealed by the head body and the cover without any gap. 
     The integrally forged iron head has a lower density in the center and a higher density in the surrounding area, which increases the error tolerance and enlarges the sweet-spot area, and also improves the sound and feel of striking. 
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a manufacturing process of a composite material integrally forged iron head in accordance with the present invention; 
         FIG. 2  is an exploded perspective view of a first preferred embodiment of the iron head made by the process in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a cover mounted on a head body of the iron head made by the process in  FIG. 1 ; 
         FIG. 4  is a perspective view of the welded cover with the head body of the iron head made by the process in  FIG. 1 ; 
         FIG. 5  is a perspective view of a semi-finished product of the iron head made by the process in  FIG. 1 ; 
         FIG. 6  is a cross sectional right side view of the semi-finished product of the iron head in  FIG. 5 ; 
         FIG. 7  is an exploded perspective view of a second preferred embodiment of the iron head in accordance with the present invention; and 
         FIG. 8  is a perspective view of the welded cover with the head body of the iron head in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     With reference to  FIG. 1 to 5 , a first preferred embodiment of a composite material integrally forged iron head of a golf club includes a head body  10 , a weight part  20  and a cover  30 . 
     With reference to  FIGS. 2 and 3 , the head body  10  has a strike face  11 , an engaging recess  12  and a placing abutment  13 . The engaging recess  12  is formed in the strike face  11  and is step-shaped. The placing abutment  13  is formed around the engaging recess  12 . The material of the head body  12  can be selected from carbon steel, such as 1020C, 1025C, 1035C, 1045C, 35CrMo, or selected from stainless steel, such as SUS303, SUS304, SUS431, 17-4PH, or selected from alloy steel. 
     The volume and the shape of the weight part  20  correspond to those of the engaging recess  12 , and the weight part  20  is mounted in the engaging recess  12 . The material of the weight part  20  is composite ceramics. Preferably, the density of the weight part  20  is around 1.3 to 3.5 g/cc. The composition of the weight part  20  contains 60 to 70% of silicon oxide, 15 to 25% of zirconium oxide, and 10 to 20% of aluminum oxide with other chemical ingredients. The weight part  20  can change the percentage of the material composition to adjust the density of the weight part  20  and has high temperature resistance from 1400° C. to 2200° C. 
     The cover  30  is mounted on the placing abutment  13  of the head body  10  and is welded with the head body  10 . The material of the cover  30  is same to the head body  10 . 
     With reference to  FIG. 1 , the manufacturing process of the composite material integrally forged iron head includes a working piece providing step S 1 , an assembling step S 2 , a cover welding step S 3 , a welding bead grinding step S 4 , and a forging step S 5 . 
     With reference to  FIG. 2 , in the working piece providing step S 1 , the head body  10 , the weight part  20  and the cover  30  are provided. 
     With reference to  FIG. 3 , in the assembling step S 2 , the weight part  20  is mounted in the head body  10 , and the cover  30  is covered on the weight part  20 . A surface of the cover  30  is flush with the strike face  11  of the head body  10 . 
     With reference to  FIG. 4 , in the cover welding step S 3 , a gap between the cover  30  and the head body  10  is welded and a welding bead is formed in the gap. The weight part  20  is sealed between the cover  30  and the head body  10 . The head body  10 , the weight part  20  and the cover  30  are integratedly formed as a forging working piece F. 
     In the welding bead grinding step S 4 , the welding bead is ground and the whole forging working piece F is ground to a predetermined weight for a forging process. 
     In the forging step S 5 , the forging working piece F is pre-heated to 700° C. to 1200° C. and is placed in a forging die to forge. With reference to  FIG. 5 , after the forging process, a semi-finished product P is made and has 0.5 to 5 g burrs generated along the contour of the semi-finished product P. 
     With reference to  FIG. 5 , the semi-finished product P is the weight part  20  integrally covered by the head body  10  and the cover  30  firmly without any gap. Because the weight part  20  has high temperature resistance and low thermal expansion coefficient in material properties, the weight part  20  will not prone to deform and generate shrinkage cavities or pinholes. In the heat-treatment process, even though the density and the thermal expansion coefficient of the weight part  20  and those of the head body  10  are different, the weight part  20  and the head body  10  will not separate or generate a gap. As the weight part  20  has lower density, the semi-finished product P has a lighter weight compared to a single material forged iron head that has the same volume, or the semi-finished product P has a larger volume compared to a single material forged iron head that has the same weight. 
     When the semi-finished product P after processing becomes an iron golf club head that has a lower density in the center and a higher density in the surrounding areas, the error tolerance is increased and the sweet-spot area is enlarged, and also the sound and feel of striking are improved. 
     With reference to  FIG. 7 , a second preferred embodiment of the composite material integrally forged iron head is similar to the first preferred embodiment. The difference is in shapes of a head body  10 A, a weight part  20 A, and a cover  30 A 
     The head body  10 A has a sole and an engaging recess  12 A formed in the sole. The weight part  20 A is mounted in the engaging recess  12 A. The cover  30 A covers the weight part  20 A and a surface of the cover  30 A is flush with a surface of the sole. After the assembling step, the cover welding step, the welding bead grinding step, and the forging step, the weight part  20 A is sealed between the head body  10 A and the cover  30 A as an integrated iron head. The engaging recess also can be formed in a back area of the head body to get same great effect. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.