US 2457084 A
Description (OCR text may contain errors)
Dec. 21, 1948. KEARsLEY ET IIAL GOLF CLUB HEAD Filed D90. 20, 1944 INVENTORS Km! J/llarczm'ak A: lbzmmfi ATTORNEYS YL CELLULDSE ETHYL CELLULOSE Patented Dec. 21, 1948 GOLF own amp I Edward P. Kearsley, Springfield, and Emil J.
Marciniak ,Ealtham rt n.
MIIL, aasignors to A. G. Spalding & Bros. Inc., Cbicopee, Ma... a corporation of Delaware Application December 20, 1944, Serial No. 568,954
4 Claims. (01. 27377) 1 This invention relates-to golf club heads particularly of the wood type which are made of molded plastic material.
'Heretofore, efforts have been made to manufacture golf club heads from various plastic materials such as pyroxylin, phenol-formaldehyde condensation products, cellulose nitrate and cellulose acetate. However, these have been unsuccessful because the heads did not possess the feel and sound of wood and disclosed properties, when in use, which rendered the clubs unsatisfactory. Some of these properties were failure and breakage under repeated blows caused during the use of the club for its intended purpose, inability of the club to maintain its resiliency so that on a hot day it would become soft and leg y while on a cold day it would be very brittle, being too heavy so that they had to be cored out to such an extent to bring them down to the desired Figure 1 is a perspective view of the club head.
Fig. 2 is a bottom view of the club head with the sole plate removed.
Fig. 3 is a section of the head taken along the line 33 of Fi 1.
Fig. 4 is a section similar to Fig. 3 of another form of the invention.
As shown in the drawings, a golf club head ID of the wood type has an integral projecting shaft receiving neck II and a striking face II which is scored longitudinally and transversely at l3 as is usual in wooden golf clubs of this character. The bottom of the head may be provided with a recess I 4 as shown in Fig. 2 in which is mounted a sole plate l5 which usually is formed of metal.
The head is preferably formed of ethyl cellulose, such as manufactured and sold under the trademark of Ethocel by the Dow Chemical Company, Midland, Michigan.
The formula of ethyl celluloseis:
2. It may be molded to substantially its final form by injection, compression or transfer molding processes. The plastic flow of ethyl cellulose can be controlled by suitable plasticizers or by controlling the degree of etherification. The heads can be molded directly on the shaft H5, or the head is to be readily removable, a sleeve, not shown,
can be molded within the bore H and be provided with means to which the shaft may be readily detachably connected.
Since the material of the head has dimensional stability during the molding operation, very little machining is required to finish the heads and this may be done readily as the material of the head can be machined without excessive strains being set up therein due to heating up of the material. I
It has been found that heads made of ethyl cellulose, and particularly thin sections thereof, such as are found around the neck and. in sections which have been cored or cut out, have excellent resistance, to impact fatigue and do not require reinforcement. By impact fatigue is meant the failure of a head to stand up under successive blows as would be encountered in the use of a golf club, and to show cracking in the face and fracture and breakage in the thin sections.
We have discovered that this property of a plastic material is essential to a successful plastic golf club head and so far as we have been 'able to determine bears no direct relation to the known characteristics of plastic materials such as impact strength, tensile strength, compression, elongation, and modulus of elasticity, etc.
Because of this characteristic, heads made of ethyl cellulose can be more readily and cheaply manufactured than prior heads since they do not have to have any reinforcements molded in them or special means for providing a reinforced mounting for the shaft thereto.
The head of the present invention is very hard and has the advantage that the striking face does not become dented through impact with the ball and the scoring thereon does not break down as in the case of a wooden club which must be completely refaced when this occurs.
Since the head is very hard, the sole plate may be secured directly thereto by self -tapping screws or other means. However, in view of the fact that the sole plates receive the greatest wear and must be frequently removed for replacement or repair by unscrewing the screws, it is preferred to mold anchoring members in the head to which the screws or othersecuring means may be connected. The anchoring means are preferably metal sleeves l9 opening into the sole plate recess and 'into which the screws 20 may be threaded.
Heads of ethyl cellulose may be cored if necessary by machining or molding to control the weight thereof since they have high resistance to impact fatigue in thin section.
Ethyl cellulose has a relatively low specific gravity so that a head of normal size has about the same weight as that of a heavy weight wooden club. Hence #1 and #2 woods" need no additional weights in themand are constructed as shown in Fig. 4, while #3 and #4 woods have a small cavity 2| therein in which a weight 22 is.
secured by a screw 23 as shown in Fig. 3. In lighter weight clubs the heads may be cored as at 2| to reduce the weight of the head.
The club head of the present invention can be made to have the appearance of a wooden club head because the material of the head takes a high polish and may be pigmented to produce various colors which may simulate a wooden club head. It has an advantage over wooden heads however in that scratches which on a Wooden head would require a complete new coat of varnish to take out may be removed by a coat of wax In the broader aspects of the invention, we are the first to provide a plastic golf club head having a high resistance to impact fatigue particularly in thin sections with a weight, sound and feel approximately that of a wooden club. 1
Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.
1. In a golf club of the "wood type. a head 01 molded ethyl cellulose.
, 2. In a golf club, a head of molded ethyl cellulose having an integral thin, unreinforced shaft receiving neck.
3. In a golf club, a head of molded ethyl ce1lulose having an integral hollow shaft receiving neck provided with walls of thin cross-section.
4. A golf club head of the wood type of moldedv ethyl cellulose.
EDWARD P. KEARSLEY. EMIL J. MARCINIAK.
' REFERENCES crran The following references are of record in the file of this patent:
UNITED STATES PATENTS