IRON TYPE GOLF CLUB HEAD WITH HIGH STRENGTH INSERT BACKGROUND OF THE INVENTION The majority of golf club heads of the iron type are made of metal, and many have recesses for receiving an insert for the striking face. In addition, golf club irons are either blades or have a cavity back defined by redistributing the weight of the club head around the perimeter thereof. Perimeter weighted clubs are recognized as increasing the moment of inertia, which increases head stability and lessens head rotation that imparts side spin on the ball. Accordingly, with perimeter weighted clubs, a golfer can hit a straighter shot, even when the ball is not struck in the center or"sweet spot"of the club face.

Metal golf club irons are generally forged or cast in a mold. Forged club heads are generally softer and provide a greater feel to the golfer, while cast club heads are harder because they can be formed of a higher strength metal than forged club heads. The present invention relates to an improved perimeter weighted club head including an insert for the striking face which is formed of a high strength material.

BRIEF DESCRIPTION OF THE PRIOR ART It is known in the patented prior art to provide golf club heads with inserts for the striking face as shown by the U. S. patents to Mahaffey No. 5,827,131 and Anderson Nos. 5,024,437,5,094,383,5,344,140, and 5,261,664. The Mahaffey patent, for example discloses a laminated lightweight insert for golf club heads of both the wood and iron type. The Anderson patents disclose iron type golf club heads having a cast metal head and a forged insert for the striking face. While

these prior heads perform satisfactorily, they do not afford the golfer with the desired feel when striking a golf ball.

Also known in the art are perimeter weighted, cavity back style golf club irons as shown by the U. S. patent to Schmidt et al No. 5,749,795. As shown therein, an iron golf club head has a first recess extending rearwardly of the striking face and an undercut recess which extends toward the top and bottom wall of the head behind the striking face. Such a head is an improvement over the prior perimeter weighted heads but still lacks a concentration of weight toward the bottom of the head.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide an iron type golf club head including a body having top, bottom, toe and heel portions and a striking face area containing a recess. An insert is secured within the recess, with an outer surface of the insert being flush with a non-recessed portion of the striking face area. The bottom portion of the body comprises the sole of the club head. It extends rearwardly and upwardly from the lower portion of the striking face area in spaced relation from the rear surface of the insert to define an undercut area in the sole behind the insert. The weight of the club head is thus distributed around the perimeter of the body and toward the sole to increase the moment of inertia and decrease rotation of the club head when it strikes a golf ball.

According to a further object of the invention, the thickness of the sole at the rear of the undercut is less than the thickness of the insert. The upwardly extending portion at the rear of the sole terminates in a top wall which is below the vertical midpoint of the body to concentrate the weight of the head toward the

bottom. The sole top wall extends between the toe and heel portions of the body and has a convex configuration.

The head body portion is formed of a forged metal such as carbon steel and the insert is formed of a high strength metal such as hardened steel or a rolled sheet material. With such a combination of materials, the golf club head provides improved feel to the golfer and the high strength insert provides maximum distance to the flight of the golf ball.

BRIEF DESCRIPTION OF THE FIGURES Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in the light of the accompanying drawings, in which: Fig. 1 is a front plan view of the iron type golf club head according to the invention; Fig. 2 is a left side view of the head of Fig. 1; Fig. 3 is a rear plan view of the head of Fig. 1; and Fig. 4 is a sectional view of the head taken along line 4-4 of Fig. 1.

DETAILED DESCRIPTION As shown in Figs. 1-3, the golf club head 2 according to the invention includes a frame or body 4 having toe 4a, heel 4b, top 4c and bottom 4d portions and a striking face area 6 containing a recess 8. An insert 10 is secured within the recess, preferably by welding although other conventional connection methods may be used. The outer surface l0a of the insert is substantially flush with a non- recessed portion 6a of the striking face area.

The body 4 is preferably formed of a forged metal such as carbon steel having an amorphous microstructure and the insert is formed of a high strength material such as hardened steel. One example of a hardened steel is a high chrome content steel known as alpha Maraging steel. Alternatively, the insert can also be formed of a rolled sheet material or a forged metal.

As shown in Figs. 3 and 4, the bottom portion 4d of the body comprises the sole of the club. The bottom portion extends rearwardly 4e from the front of the club and upwardly 4f to a location below the top portion 4c of the body and spaced from the rear surface of the insert. The sole thus defines an undercut area 12 in the bottom portion of the body behind the insert. The thickness t of the body at the intersection of the rearwardly extending sole bottom portion 4e and the upwardly extending sole bottom portion 4f is less than the thickness of the insert. Thus, if the thickness of the insert is between 1.0 and 4.0mm, a preferably between 2.0 and 2.5mm, the thickness t is less than the insert thickness. The forward surface of the upwardly extending sole bottom portion 4f is preferably parallel to the rear surface of the insert so that the width of the undercut area defined between the insert 10 and the portion 4f is constant. Alternatively, the forward surface of the upwardly extending sole bottom portion 4f may be angled inwardly as shown in phantom in Fig. 4 so that the width of the undercut area tapers toward the bottom thereof.

The top wall 4g of the upwardly extending sole bottom portion 4f extends between the toe and heel portions of the body and has a convex configuration as shown in Fig. 3. The top wall is arranged below the vertical midpoint of the body so that the weight of the body is concentrated toward the bottom portion of the body. Since the body contains a recess, weight is also distributed about the perimeter of the body. This weight distribution increases the moment of inertia of

the club head and decreases rotation of the head when it is used to strike a golf ball.

The iron type golf club head of the invention provides improved feel to the golfer because the forged body is softer and thus provides feedback to the golfer when a ball is struck. Maximum distance in the flight of the ball is obtained by using the higher strength insert. The perimeter weighting of the club provides a larger"sweet spot"in the club striking face so that less precision is required when hitting the ball. The concentration of weight toward the bottom of the head increases the trajectory of the ball and enables the golfer to get the ball airborne from difficult lies.

While in accordance with the provisions of the patent statute the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those of ordinary skill in the art that various changes and modifications may be made without deviating from the inventive concepts set forth above.