Abstract:
A connecting method for the wax patterns of the golf club head includes the steps of: prefabricating a first wax pattern and a second wax pattern, the first wax pattern providing with an engaging portion for engaging with the second wax pattern; employing a temperature difference to generate a manufacturing volume tolerance between the first wax pattern and the second wax pattern; combining the engaging portion of the first wax pattern with the second wax pattern; and cooling the first wax pattern to shrink the engaging portion so as to fittingly combine the first wax pattern with the second wax pattern.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a connecting method for wax patterns of a golf club head. More particularly, the present invention relates to the connecting method of employing volume&#39;s shrinkage of wax patterns for combining with each other that may simplify an assembling process for the wax patterns of the golf club head. 
     2. Description of the Related Art 
     Referring initially to  FIGS. 1 through 3 , Taiwanese Pat. Publication No. 514574 discloses a manufacturing method for a golf club head. The manufacturing method includes the steps of:
         1. Separately prefabricating two wax patterns  10 ,  20 , as shown in  FIG. 1 . Wax liquid is injected into a first mold assembly and a second mold assembly (not shown) to form two wax patterns  10 ,  20 , such as a main-body wax pattern  10  and a striking-plate wax pattern  20 .   2. Adhering the two wax patterns, as shown in  FIG. 1 . The two wax patterns  10 ,  20  are adhered to constitute a combination member.   3. Forming a ceramic shell  30  in slurry, as shown in  FIG. 2 . The combination pattern of the two wax patterns  10 ,  20  is immersed in slurry that forms a ceramic shell  30 . After heating, the two wax patterns encompassed in the ceramic shell  30  are changed to the melting wax liquid for discharging it from the ceramic shell  30 . The ceramic shell  30  forms an inward protrusion for correspondingly casting a rear recession of a golf club head, and a pouring gate at its side portion.   4. Investment casting an iron club head within the ceramic shell  30 , as shown in  FIG. 3 . A melting alloy is poured into the ceramic shell  30  to fabricate the iron club head. After cooling, the iron club head casting  40  is formed within the ceramic shell  30  which can be broken to take out an integrated member of the iron club head casting  40 .       

     According to the above-mentioned manufacturing method, the club head casting  40  forms a rear recession  41  at its rear side to constitute an undercut configuration that may enhance striking performance and satisfy the need of product quality. However, there are several drawbacks in manufacturing. For example, in adhering process the wax liquid is generally filled within a groove extending between the main-body wax pattern  10  and the striking-plate wax pattern  20 . As best shown in  FIGS. 1   a ,  2   a  and  3   a , when the filling process is incomplete, there exists a gap (a) remained between the main-body wax pattern  10  and the striking-plate wax pattern  20 . Thus, the slurry may invade into the gap (a) in the immersing process for forming the ceramic shell. Consequently, the interior of the ceramic shell  30  may consists of burrs (b) after lost-wax processing. In investment casting process, the club head casting  40  may form many cracks (c) between a main-body wax portion and a striking-plate wax portion due to the burrs (b). Furthermore, an excess of the wax liquid cause an overflow from the groove between the main-body wax pattern  10  and the striking-plate wax pattern  20 . After hardening, although the harden wax may fill the groove formed between the main-body wax pattern  10  and the striking-plate wax pattern  20 , an irregular surface (not shown) may remain on the groove of the combination member. Hence, there is a need for eliminating the irregular surface of the club head casting  40  by precision machining or polishing. This results in an additional process in manufacturing the golf club head. Especially, if the irregular surface is remained in the rear recession  41  of the club head casting  40 , a machining tool is hard or inconvenient for inserting into the rear recession  41  of the club head casting  40  for processing. Certainly, it may result in difficulty of machining, and an increase of manufacturing cost and time. 
     The present invention intends to provide a connecting method for wax patterns a golf club head which delays cooling a first wax pattern in proper and cools a second wax pattern. A manufacturing volume tolerance is enlarged between the first and second wax patterns for conveniently combining each other in such a way to mitigate and overcome the above problem. 
     SUMMARY OF THE INVENTION 
     The primary objective of this invention is to provide a connecting method for wax patterns a golf club head which employs a temperature difference of the wax patterns to generate a manufacturing volume tolerance between the wax patterns. Thereby the wax patterns are able to fittingly combine each other that may increase the overall quality of the golf club head. 
     The connecting method for the wax patterns of the golf club head in accordance with the present invention includes the steps of: prefabricating a first wax pattern and a second wax pattern, the first wax pattern providing with an engaging portion for engaging with the second wax pattern; employing a temperature difference to generate a manufacturing volume tolerance between the first wax pattern and the second wax pattern; combining the engaging portion of the first wax pattern with the second wax pattern; and cooling the first wax pattern to shrink the engaging portion so as to fittingly combine the first wax pattern with the second wax pattern. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described in detail with reference to the accompanying drawings wherein: 
         FIG. 1  is a cross-sectional view of wax patterns of a conventional golf club head in accordance with the prior art; 
         FIG. 1   a  is an enlarged view, in  FIG. 1 , of the wax patterns of the golf club head in accordance with the prior art; 
         FIG. 2  is a cross-sectional view of a ceramic shell of the golf club head in accordance with the prior art; 
         FIG. 2   a  is an enlarged view, in  FIG. 2 , of the ceramic shell of the golf club head in accordance with the prior art; 
         FIG. 3  is a cross-sectional view of a club head casting in accordance with the prior art; 
         FIG. 3   a  is an enlarged view, in  FIG. 3 , of the club head casting in accordance with the prior art; 
         FIG. 4  is a block diagram of a connecting method for wax patterns a golf club head in accordance with the present invention; 
         FIG. 5  is an exploded perspective view of wax patterns of the golf club head in a first step of a connecting method in accordance with the first embodiment of the present invention; 
         FIG. 6   a  is a cross-sectional view of the striking-plate wax pattern of the golf club head in a second step of the connecting method in accordance with the first embodiment of the present invention; 
         FIG. 6   b  is a cross-sectional view, similar to  FIG. 6   a , of the shrunk striking-plate wax pattern of the golf club head in a second step of the connecting method in accordance with the first embodiment of the present invention; 
         FIG. 7   a  is a cross-sectional view of the combined wax patterns of the golf club head in a third step of the connecting method in accordance with the first embodiment of the present invention; 
         FIG. 7   b  is a cross-sectional view of the combined wax patterns of the golf club head in a fourth step of the connecting method in accordance with the first embodiment of the present invention; 
         FIG. 8  is a cross-sectional view of a ceramic shell of the golf club head in accordance with the first embodiment of the present invention; 
         FIG. 9  is a cross-sectional view of a club head casting in accordance with the first embodiment of the present invention; 
         FIG. 10  is a cross-sectional view of a main-body wax pattern of the golf club head in a second step of the connecting method in accordance with a second embodiment of the present invention; 
         FIG. 11   a  is a cross-sectional view of the combined wax patterns of the golf club head in a third step of the connecting method in accordance with the second embodiment of the present invention; and 
         FIG. 11   b  is a cross-sectional view of the combined wax patterns of the golf club head in a fourth step of the connecting method in accordance with the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The reference numerals of the first and second embodiments of the present invention have applied the identical numerals of the conventional golf club head members, as shown in  FIGS. 1 through 3 . The construction of golf club head member members in accordance with embodiments of the present invention have similar configuration and same function as that of the conventional golf club head members and detailed descriptions may be omitted. 
     Referring to  FIGS. 4 and 5 , a first step of the connecting method for the wax patterns in accordance with a first embodiment of the present invention separately prefabricates a first wax pattern  10  and a second wax pattern  20 . The construction of the first wax pattern  10  provides with a rear opening  11  and an engaging portion  12  connected thereto. First, wax liquid is injected into a mold assembly (not shown) for separately prefabricating the first wax pattern  10  and the second wax pattern  20 . Preferably, the first wax pattern  10  and the second wax pattern  20  are club component patterns selected from a group consisting of a main-body wax pattern and a striking-plate wax pattern for example. In the illustrated embodiment the opening  11  of the main-body wax pattern  10  connects the rear side to the front side. Furthermore, the rear opening  11  of the first wax pattern  10  connects to the engaging portion  12  proximate the front side for engaging with the second wax pattern  20 . 
     Turning now to  FIGS. 4 ,  6  and  6   a , a second step of the connecting method for the wax patterns in accordance with the first embodiment the present invention employs a temperature difference to generate a manufacturing volume tolerance between the first wax pattern  10  and the second wax pattern  20 . The material of wax may expand when hot and shrink when cool, which has a shrinkage rate in length ranging between 8/1000– 17/1000. To accomplish such a manufacturing volume tolerance, the second wax pattern  20  is processed to cool in proper for shrinking volume thereof. After cooling down to a predetermined low temperature, a first outer diameter L 2  of the second wax pattern  20  is reduced to a second outer diameter L 2 ′. In order to maintain an inner diameter L 1  of the engaging portion  12  of the first wax pattern  10  in a greater length, the first wax pattern  10  is thermal-insulated at a predetermined high temperature that is relatively higher than that of the second wax pattern  20 . In the same temperature, the first outer diameter L 2  of the second wax pattern  20  may be slightly greater than the inner diameter L 1  of the engaging portion  12  of the first wax pattern  10  prior to cooling the second wax pattern  10 . In different temperature, the second outer diameter L 2 ′ of the second wax pattern  20  may be specifically smaller than the inner diameter L 1  of the engaging portion  12  of the first wax pattern  10  for loose-fitting. Because of this, the temperature difference permits a desired manufacturing volume tolerance between the first wax pattern  10  and the second wax pattern  20 . 
     Turning now to  FIGS. 4 and 7   a , a third step of the connecting method for the wax patterns in accordance with the first embodiment of the present invention initially combines the engaging portion  12  of the first wax pattern  10  with the second wax pattern  20 . After cooling the second wax pattern  20 , the second outer diameter L 2 ′ is able to insert into the inner diameter L 1  of the engaging portion  12  in convenience by means of loose fitting. In assembling, the inner diameter L 1  of the engaging portion  12  of the first wax pattern  10  may not interfere with the second outer diameter L 2 ′ of the second wax pattern  20  such that a connection boundary between the first and the second wax patterns may not be destroyed. Consequently, it ensures the constructions of the first wax pattern  10  and the second wax pattern  20  in good condition. 
     Turning now to  FIGS. 4 and 7   b , a fourth step of the connecting method for the wax patterns in accordance with the first embodiment of the present invention cools the first wax pattern  10  to shrink the engaging portion  12 . Thereby the engaging portion  12  fittingly combines the first wax pattern  10  with the second wax pattern  20  to form a wax club head  100 . To this end, the engaging portion  12  of the first wax pattern  10  may be gradually shrunk to engage with an outer circumference of the second wax pattern  20  when the temperature is successively decreased. Finally, since the second outer diameter L 2 ′ is substantially equal to or slightly greater than the reduced inner diameter of the engaging portion  12 , an inner circumference of the engaging portion  12  fittingly combines with the outer circumference of the second wax pattern  20 . Consequently, there is no gap remained between the inner circumference of the engaging portion  12  and the outer circumference of the second wax pattern  20  that may increase the overall quality of the golf club head. 
     Turning now to  FIGS. 8 and 9 , subsequently, the wax club head  100  is immersed in slurry to form a ceramic shell  30  and heats the ceramic shell  30  for lost-wax processing. Next, a melting alloy is poured into the ceramic shell  30  to fabricate a club head casting  40 . Finally, the club head casting  40  can be taken out by breaking the ceramic shell  30 . 
     In the illustrated embodiment the wax club head  100  can omit a filling process of wax liquid that avoids an overflow due to an excess of the wax liquid or incomplete filling which causes an irregular surface. This results in the wax club head  100  forming a smooth surface instead of an irregular surface. Consequently, the club head casting  40  has a smooth surface that may increase the overall quality of the golf club head. Also, the smooth surface of the club head casting  40  results in a decrease in the need of precision machining that may simplify the machining process and reduce manufacturing cost. 
     Turning now to  FIGS. 10 ,  11   a  and  11   b , the connecting method for the wax patterns in accordance with a second embodiment of the present invention, in comparison with the first embodiment, employs a heater (not shown) heating the first wax pattern  10  to maintain it at a predetermined high temperature. Once the predetermined low temperature of the second wax pattern  20  is relatively lower than that of the first wax pattern  10 , a desired manufacturing volume tolerance between the first wax pattern  10  and the second wax pattern  20  is obtained. However, for strength and rigidity, the heating temperature of the first wax pattern  10  is considerably lower than a melting point so that the construction of the first wax pattern  10  is relatively rigid and strong to withstand normal usage in manufacture. In this circumstance, the inner diameter L 1  of the engaging portion  12  is remained in a greater length. As best shown in  FIG. 11   a , after successively heating the first wax pattern  10 , the inner diameter L 1  of the engaging portion  12  of the first wax pattern  10  may be specifically greater than the outer diameter L 2 ′ of the second wax pattern  20  for loose-fitting. As best shown in  FIG. 11   b , the inner diameter L 1  of the engaging portion  12  of the first wax pattern  10  may be gradually shrunk to engage with the outer circumference L 2 ′ of the second wax pattern  20  when the temperature is successively decreased. Finally, since the second outer diameter L 2 ′ is slightly greater than the reduced inner diameter of the engaging portion  12 , an inner circumference of the engaging portion  12  fittingly combines with the outer circumference of the second wax pattern  20  to form a wax club head  100 . Consequently, there is no gap remained between the inner circumference of the engaging portion  12  and the outer circumference of the second wax pattern  20  that may increase the overall quality of the golf club head. Referring back to  FIGS. 8 and 9 , the wax club head  100  is used to fabricate the ceramic shell  30  and the club head casting  40 . 
     Referring back to  FIGS. 3 and 3   a , the conventional club head casting  40  has many cracks (c) due to the gap (a) formed between the main-body wax pattern  10  and the striking-plate wax pattern  20 . Referring back to  FIG. 4 , the first wax pattern  10  is thermal-insulated or heated at a predetermined high temperature to obtain a desired manufacturing volume tolerance between the first wax pattern  10  and the second wax pattern  20 . Consequently, it may increase the overall quality of the golf club head. 
     Although the invention has been described in detail with reference to its presently preferred embodiment, it will be understood by one of ordinary skill in the art that various modifications can be made without departing from the spirit and the scope of the invention, as set forth in the appended claims.