Abstract:
This invention relates to a golfing putter and, more particularly, a golfing putter ( 1 ) for helping golfers strike a golf ball ( 17 ) consistently without inducing backspin on the ball. The golfing putter ( 1 ) comprises a head ( 2 ) fixed to a shaft ( 3 ). The head ( 2 ) has a front face ( 7 ) for striking the golf ball ( 17 ), and an upper face ( 6 ) disposed in use towards the golfer. The vertical centre of mass ( 8 ) is behind an upper portion of the front face ( 7 ) of the head ( 2 ). The head ( 2 ) has at least in a central portion ( 35 ) of the front face ( 7 ) an inverted L-shaped cross-section with the top face ( 6 ) forming an upper arm ( 36 ) of the L-shape and the front face ( 7 ) forming the front arm ( 37 ) of the L-shape. The front arm ( 37 ) is thinner than the top arm ( 36 ). The head therefore has a vertical centre of mass ( 8 ) behind an upper third of the front face ( 7 ) of the head ( 2 ) above the impact point with the golf ball ( 17 ).

Description:
BACKGROUND  
       [0001]     a. Field of the Invention  
         [0002]     This invention relates to a golfing putter for striking a golf ball towards a golf hole.  
         [0003]     b. Related Art  
         [0004]     When playing golf the putter is used to strike a golf ball into the hole from the green or around the green. The golfer addresses the ball with the putter, which is then swung back and forward striking the ball towards the hole on the forward swing. On striking the ball the putter propels the ball towards the hole overcoming the inertia of the stationary ball.  
         [0005]     A golfer when preparing to make a putt takes great care in setting up to align the putter and his/her body so as to maximise the effectiveness of the putt. The alignment of the head relative to and eyes along the line of the putt is seen as an important element in this process.  
         [0006]     The design of the putting head has a crucial effect on the quality and repeatability of the strike. Modern putters are typically made with some of their mass situated towards the toe and heel of the putting head. This is to increase size of the sweet spot, the effective lateral centre of mass of the putting head, thereby helping the golfer hit the ball with a consistent quality of strike despite minor errors in the swinging of the putter. Equally typically, many putters have much of their mass on the bottom of the putting head moving the vertical centre of mass towards the bottom of the face. The face of a putting head is typically angled slightly up from 90° so that the ball is not driven into the ground or caused to skid along the ground following the strike. This also helps the golfer hit the ball with a consistent quality of strike.  
         [0007]     This type of construction also has the effect of deadening the noise of the strike, owing to the fact that the striking surface is bounded above and below by two portions of the putter having higher mass, namely the toe or heel of the putting head and the shaft of the putter. Since noise during golfing can be a distraction, some designs of putter have been optimised to minimise the noise of the strike.  
         [0008]     It is the case that putters may induce backspin onto the ball which affects the roll of the ball immediately after the ball is struck and for up to 20% of the length of the putt. This is principally caused by the centre of mass and momentum of the putting head being below the centre of the ball. An analogy is in the strike of a billiard ball where a backspin is induced when the cue hits the ball below its centre line (its centre of mass). Although backspin can be beneficial in some circumstances, for most golfers this present difficulties because of the length and speed of the putt being dependant on both the swing of the putter by the golfer and on the potentially variable quality of the putting surface. It has been found by the inventor that the combination of a low centre of gravity and these other factors reduces the predictability in the direction and distance travelled by the ball—both essential aspects of control when a golfer is putting.  
       SUMMARY OF THE INVENTION  
       [0009]     It is an object of the invention to provide a putter that addresses these issues.  
         [0010]     Accordingly, the present invention provides a golfing putter for putting a golf ball, comprising a shaft which may be grasped by a golfer when putting the golf ball, and a head fixed at an end of the shaft, the head having a front face for striking the golf ball, and an upper face disposed in use towards the golfer, in which: the vertical centre of mass is behind an upper portion of the front face of the head; the head has at least in a central portion of the front face an inverted L-shaped cross-section with the top face forming an upper arm of the L-shape and the front face forming a front arm of the L-shape; and the front arm is thinner than the upper arm.  
         [0011]     In a preferred embodiment of the invention, the centre of mass is behind an upper third portion of the front face of the head.  
         [0012]     In one embodiment of the invention, the L-shaped cross-section extends to the ends of the head.  
         [0013]     In an alternative embodiment of the invention, the inverted L-shaped cross-section terminates at ends of the head at downwardly depending lobes.  
         [0014]     To help raise the centre of gravity of the head with respect to a central portion of the front face, it is preferred if the bottom of the front face is below the lower limits of the end lobes.  
         [0015]     Also to raise the centre of gravity, lobes may extend upwardly from the top face at the two ends of the head.  
         [0016]     In one embodiment of the invention, lobes extend upwardly from the top face above the downwardly extending lobes.  
         [0017]     Preferably, the top face is wider than the front face is tall.  
         [0018]     To help the golfer align the head, the top face may be reflective, for example being polished metal. A magnified image may be seen in the top face if this is concave, for example cylindrically concave, when viewed from above.  
         [0019]     The concave top face has a focal length of between 1 m and 20 m, but it is preferred if the focal length is between 3 m and 5 m.  
         [0020]     The front face should have some flexibility or resiliency. Therefore, the front face may be less than 5 mm thick, and is preferably less than 3 mm thick.  
         [0021]     The upper face may be polished to a shiny or mirror finish, allowing the golfer to see her/his reflection. The front face should be thick enough to resist any permanent distortion due to the strike of a golf ball but preferably also thin enough to provide differentiated noises according to whether the strike is in the centre of the sweet spot, below it or to the side of it. It has been found to be particularly advantageous if the bottom front face extends below the lower limits of the end lobes, as this can enhance the ringing sound.  
         [0022]     Because the vertical centre of mass is behind an upper portion of the front face of the putting head, the golfer may feel the quality of strike through his/her hands. For example, an off centre strike can cause a slight twisting of the shaft.  
         [0023]     The golfer may therefore more readily strike a golf ball correctly with said centre of mass above the point of impact with the golf ball.  
         [0024]     The inventor has found that the noise of the strike of the ball against the putting head front face can also provide useful information as to the nature of the strike. In contrast, many modern putters have been designed to all but eliminate this element—through the use of plastic or resin inserts and thick front faces.  
         [0025]     Also according to the invention, there is provided a method of striking a golf ball, using a golfing putter according to the invention, comprising the step of using the putter to strike the ball so that the point of contact between the front face of the head and the golf ball is below said centre of mass of the head. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]     The invention will now be further described, by way of example only, and with reference to the accompanying drawings, in which:  
         [0027]      FIG. 1  is a plan view from the front of a right handed golfing putter according to a first embodiment of the invention, showing a putting head fixed to a shaft;  
         [0028]      FIG. 2  is an enlarged fragmentary perspective view of the putter of  FIG. 1 , showing a front surface and an upper surface of the putting head;  
         [0029]      FIG. 3  is an enlarged fragmentary perspective view of the putter of  FIG. 1 , showing rear surfaces and the upper surface of the putting head, including two downwardly extending lobes at near and far ends of the putting head;  
         [0030]      FIGS. 4 and 5  are, respectively, a top plan view and a front plan view of the putting head of  FIG. 1 , prior to attachment to the shaft;  
         [0031]      FIG. 6  is a cross-section view in a vertical plane through the putting head, taken along the line VI-VI of  FIG. 5 ;  
         [0032]      FIGS. 7, 8  and  9  are, respectively plan views from below, the rear and the far side of the putting head;  
         [0033]      FIG. 10  is an enlarged fragmentary plan view of the rear surfaces of a right handed golfing putter according to a second embodiment of the invention, similar to that of the first embodiment, but having a putting head with a cylindrically concave upper surface;  
         [0034]      FIG. 11  is a cross-section view similar to that of  FIG. 6 , showing the putting head striking a golf ball and showing the point of contact between the front face of the putting head and the golf ball, the point of contact being below a centre of mass of the putting head;  
         [0035]      FIG. 12  is an enlarged fragmentary plan view of the rear surfaces of a right handed golfing putter according to a third embodiment of the invention, similar to that of the first embodiment, but having any downwardly extending lobes at near and far ends of the putting head; and  
         [0036]      FIG. 13  is an enlarged fragmentary plan view of the rear surfaces of a right handed golfing putter according to a fourth embodiment of the invention, similar to that of the first embodiment, but not having also upwardly extending lobes at near and far ends of the putting head. 
     
    
     DETAILED DESCRIPTION  
       [0037]      FIGS. 1, 2  and  3  show a first embodiment of a golfing putter  1 . The putter  1  has a tapered chromed steel shaft  3  and a brass putting head  2 . A narrow end  20  of the shaft  4  is attached to the brass putting head  2 . An opposite wider end  21  of the shaft  3  passes inside a rubber hand grip  4 . The shaft  3  and grip  4  are similar to those used for other golfing putters.  
         [0038]     As shown in  FIG. 2 , the head  2  has a hole  5  into which the narrow end  20  of the shaft  3  is fitted, for example using an interference fit. Optionally, a chromed steel bushing  22  may surround the narrow end  20  of the shaft  3  to make a more secure fit to the hole  5 . The shaft  3  may be bonded to the putting head  2  within the hole  5  or bushing  22  by an epoxy resin (not shown).  
         [0039]     The putting head  2  has a rectangular flat top face  6 . The shaft  3  is shown at an angle of 15° degrees to a normal of the top face  6  of the putting head  2 , but may be between 10° and 45°.  
         [0040]     The top face  6  is bounded by straight parallel forwards and rearwards upper long edges  24 , 25  and by straight parallel near and far upper short edges  26 , 27 . The overall length of the putting head  2  is 200 mm, but may be between 90 mm and 300 mm. The width of the putting head  2  is 35 mm but may be between 15 mm and 100 mm. The golfing putter  1  illustrated has a total length including the putting head  2 , shaft  3  and grip  4  of 650 mm.  
         [0041]     The putting head  2  will now be described in more detail with reference now also to  FIGS. 4-9  and  11 . The putting head  2  has a front or striking face  7  for striking a golf ball  17 . The front face  7  depends downwardly from the top face  6  along the full extent of the forwards edge upper  24  of the top face  6 . The front face  7  is roughly rectangular, being bounded by the straight forwards upper edge  24  and by a convexly curved lower edge  29 . Towards near and far upper edges  26 , 27 , the curved lower edge  29  bends into convexly curved near and far side edges  32 , 33  to the front face  7 .  
         [0042]     The front face  7  extends in a central portion, generally indicated by reference numeral  35 , a distance of 30 mm in a vertical direction, but may be between 15 mm and 50 mm. The top face  6  is preferably wider than the front face  7  is tall. For the first embodiment  1 , the top face  6  extends 40 mm in a horizontal direction.  
         [0043]     With reference now particularly to  FIGS. 6 and 11 , the putting head  2  has a hollow recess  28  in a central lower rear portion of the putting head  2 . The recess  28  is generally rectangular, apart from a protrusion  39  into the recess that surrounds the hole  5 , being bounded on four adjacent sides. Towards the top face  6  the recess  28  is bounded by an upper arm  36 , and towards the front face  7  the recess is bounded by a front arm  37 . In this example both arms  36 , 37  are plates, having roughly flat inner surfaces  44 , 45  which are approximately parallel with the opposite top face  6  and front face of the putting head  2 .  
         [0044]     Towards the near and far sides  32 , 33  the recess  28  is bounded by two similar downwardly depending lobes  40 , 41 . In the cross-sections of  FIGS. 6 and 11 , it can be seen than the upper and front arms  36 , 37  have an inverted L-shaped cross-section. This L-shaped cross-section extends across the central portion  35  of the front face  7 .  
         [0045]     In the first embodiment of the golf putter  1 , the centre of mass  8  of the putting head  2  is denoted by the letter “X” in  FIGS. 6 and 11 . As indicated in  FIG. 5 , the centre of mass  8  of the putting head  2  is behind an upper third portion  48  of the front face  7 .  
         [0046]     In order to help raise the centre of gravity into the upper third portion  48 , the front arm  37  is thinner than the upper arm  36 . In the present example, the overall thickness of the front arm  37  is 3 mm but may be between 1 mm and 10 mm. The overall thickness of the upper arm  36  is 4 mm but may be between 1 mm and 10 mm. The angle of the front face  7  to the top face  6  is preferably at least a right angle and preferably less than 100°, and in the illustrated example is 93°.  
         [0047]     Other features of the putting head also help to raise the centre of gravity  8 . For example, the convexly curved lower front edge  29  rises towards the near and far edges  32 , 33  of the front face  7  which in a good putt are not used to strike the ball. The convex lower edge  29  also raises the average height of the side lobes  40 , 41 , which raises the centre of gravity  8 .  
         [0048]     Although not shown, the recess  28  may be filled with a material of lower density than that of the rest of the putting head  2  in order to make a flat lower surface to contact the ground  30 .  
         [0049]     The placement of the lobes  40 , 41  at opposite lateral sides of the putting head  2  helps to increase the moment of inertia of the putting head  2  about an axis through the shaft  3 , thereby reducing the tendency of the front face to pivot about this axis in the event the golf ball  17  is struck well towards either the near or far edges  32 , 33  of the front face  7 . This end weighting of the putting head  2  increases the size of the sweet spot  50  and helps to increase the accuracy of such imperfect putts.  
         [0050]     As can be seen in  FIG. 11 , which shows the golf ball  17  resting on a putting surface  30 , the placement of the centre of gravity  8  above but near a sweet spot region  50  helps to ensure that when the golf ball  17  is struck, a horizontal centre line  15  through the golf ball  17  is below the centre of gravity  8 . Then, when the golf ball  17  is struck, the putting head  2  will tend to impart top spin to the golf ball  17 . This is because there will be a small net upwards force on the putting head  2 , owing to the vertical offset between the centre of mass  8  and the point at which the front face  7  strikes the golf ball  17 .  
         [0051]     Another factor which tends to impart top spin is the resiliency of the front arm  37 , which is not completely rigid, but does have some flexibility, particularly if formed in a metal material. This resiliency results from the front arm  37  being unbounded by any adjacent material along the lower front edge  29 . The front face  37  therefore tends to pivot backwards from the front edge  24  when the golf ball  17  is initially struck, and then flex forwards as the golf ball  17  leaves the front face  7 . When the angle of the front face  7  is such that the front face  7  is angled forwards towards the front lower edge  29 , as drawn in  FIGS. 6 and 11 , then the forwards rebound of the front face  7  will tend to lift the golf ball  17  slightly and impart a forwards rolling motion.  
         [0052]     In addition, the inventor has found that this flexing of the front arm results in an audible ringing tone, the pitch of which is an indication of whether or not the ball has been struck in or near the sweet spot  50 . The ringing tone is louder when the front arm  37  is thinner than the upper arm  36 .  
         [0053]      FIG. 10  shows a second embodiment  101  of the golfing putter, in which features similar to those of the first embodiment  1  are indicated by reference numerals incremented by  100 . The second embodiment  101  is similar to the first embodiment  1  except that the putting head  102  is cylindrically curved about an axis parallel to the strike axis  15  through the golf ball. This provides two benefits. First the centre of gravity  108  is raised owing to the higher positioning of the side lobes  140 , 141 . Second, the top face  106  can be used to help the golfer align the putter  101 , if the tope face  106  is polished or made reflective. As long as the focal length of the cylindrically curved top face is greater than the distance to the golfer&#39;s eyes, the golfer will see a magnified image, for example an image of his face, in the top surface. This can help the golfer repeatedly to position the putting head in the same orientation prior to striking the golf ball  17 .  
         [0054]      FIG. 12  shows a third embodiment  201  of the golfing putter, in which features similar to those of the first embodiment  1  are indicated by reference numerals incremented by  200 . The third embodiment  201  differs from the first embodiment  1  in that there are no downwardly depending lobes or other weights at the lateral near and far edges  232 , 233  of the putting head  202 . Again, this can help to raise the centre of gravity  208 , although the putting head  202  may need to extend over a longer distance between the near and far side edges  232 , 233  in order to compensate for a correspondingly lower moment of inertia about an axis along the shaft  203 . It may, however, then be possible to have a flatter lower front edge  229 , which can help in aligning the putter  201  to be always at the same angle with respect to the ground prior to striking the ball  17 .  
         [0055]      FIG. 13  shows a fourth embodiment  301  of the invention which differs from the first embodiment  1  in that weight has been added to the ends of the flat surface  6  in the form of two opposite lateral lobes  332 , 333  that extend both downwardly and upwardly with respect to the upper arm  336  of the putting head  302 . This helps to raise the centre of gravity  308  while increasing the moment of inertia of the putting head  302  with respect to an axis along the shaft  303 . Again, it may then be possible to have a flatter lower front edge  329 , which can help in aligning the putter  301  to be always at the same angle with respect to the ground prior to striking the ball  17 .  
         [0056]     The various embodiments of the putting head  2 , 102 , 202 , 302  according to the invention have a vertical centre of mass  8 , 108 , 208 , 308  behind an upper third of the front face  7  of the head above the normal impact point  50  with the golf ball  17 . The golf putter  1 , 101 , 210 , 301  according to the invention helps to remove the design-induced causes of back spin of the ball, thereby providing a consistent strike with more predictable results, and so allowing the golfer to concentrate on the direction and distance of the putt. The invention also facilitates the maximisation the size of the sweet spot  50  by moving as much mass as possible away from the toe and heel of the putting head.  
         [0057]     A further advantage of the invention is that the top face of the putting head can be used by the golfer in aligning her/his head and eyes. For example, if the top face is polished, then the golfer may see a reflection of his/her head and eyes and adjust their position accordingly. In addition, it is possible to ‘tune’ the front face of the putting head so that it provides clear audible information as to the nature of the strike by the noise that the strike makes.  
         [0058]     A yet further advantage of the invention is that the lower front edge of the front face presents less surface area to a putting surface, for example a putting green, than prior art putters which have an extensive heal or toe. Therefore, if the golfer inadvertently touches the ground when putting, there is less friction between the ground and the relatively thin lower edge. Thus, since friction is reduced with less surface area in contact with the putting surface, the stroke is less affected than would otherwise be the case.  
         [0059]     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately, or in any suitable combination.  
         [0060]     It is to be recognized that various alterations, modifications, and/or additions may be introduced into the constructions and arrangements of parts described above without departing from the spirit or scope of the present invention, as defined by the appended claims.