Abstract:
A golf practice device is disclosed that simulates the response of natural turf when impacted by the golf club head. The device comprises a platform for supporting the golfer and a divot simulator insert installed in a cavity area within the platform. The divot simulator insert has a base; a tray rests on top of the base with a simulated turf surface fitted therein. A cover is provided to conceal the interior and strengthen the base. When a ball placed on the simulated turf surface is struck by a golf club, the force imparted to the device sends the tray together with the simulated turf surface sliding forward, thus simulating the feel of hitting off natural turf and taking a divot. Means comprising compression springs fitted over guide rails are provided to control the sliding forward and retraction to their original position of the tray and the simulated turf surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a golf practice device, and more particularly to a golf practice device that (1) has a platform for supporting the golfer and securing a divot simulator insert installed therein, and (2) the divot simulator insert includes a surface component that yields and moves when impacted by the head of a golf club to simulate the response of natural turf and facilitate the practice and development of a correct golf swing. 
     2. Prior Art 
     To be skilled at the techniques of golf requires a golfer to practice regularly beyond the time spent on playing the game on golf courses. Many indoor/outdoor golf practice facilities have been created to accommodate golfers&#39; need to practice, and the use of golf practice mats at these facilities is a common and long-established practice. The conventional golf practice mats are available in a variety of materials and have a surface layer simulating natural grass. These mats generally perform adequately for practicing wood shots off a tee. However, they are deficient for practicing iron shots and may actually impede the development of a correct swing. 
     A correct iron shot requires the golf club head to impact the golf ball on the downswing momentarily before it reaches the lowest point of the swing arc, i.e., the path of the golf club head during a swing. The descending club head will naturally remove a small patch of turf, known as a divot, below or immediately in front of the ball. Conventional golf practice mats are generally of stiff, unyielding construction and do not allow the action of taking a divot. A correct golf swing practiced on such a mat will actually produce the wrong “feel” as the club head, after hitting the ball, is impeded by and bounces off the mat. Further, to lessen the shock to the wrists and elbows and risk of injury, the golfer may alter his swing to “scoop” or sweep the ball off the mat cleanly instead of hitting “down and through” and thus develop an incorrect way of hitting iron shots. Also, when the golfer makes an incorrect swing and strikes the mat behind the ball, i.e., making a “fat” shot, the shock from hitting a hard and unyielding surface can lead to injuries to elbows and other joints. To make matters worse, the fear of experiencing pain may cause the golfer to tense up and produce more bad shots thus negating the benefit of practice. Lastly, some golf practice mats have a surface layer consisting of long fibers or inverted brushes to help reduce club head bounce and risk of injury. However, these mats may have too much “give” and more closely simulate fringe grass than fairway turf. 
     Many golf practice devices have been conceived over the years incorporating a hitting surface that yields or moves when struck by the head of a golf club to simulate the response of natural turf; some are designed to be portable so golfers can carry and use them at golf practice facilities. Examples are shown in the following U.S. patents or pending applications. 
     U.S. Pat. No. 6,156,396 issued to Florian discloses a device consists of a base pad formed of a resilient elastomeric material and an artificial grass carpet positioned on the base pad. When a golf ball on the carpet surface is struck, the carpet slides a limited distance and is then returned by an elastic biasing mechanism. 
     U.S. Pat. No. 5,897,443 issued to Glaser discloses a device comprises a mat with an insert, which further consists of a continuous belt extending around parallel rollers to create a movable ball supporting surface and a tray holding deformable material placed beneath the belt upper surface. Striking of the belt upper surface depresses the belt downwardly while rotating it toward the front of the mat. 
     U.S. Pat. No. 5,888,147 issued to Luedtke discloses a device comprises an anchor piece and a divot piece connected by elastic rubber bands. 
     U.S. Pat. No. 5,692,967 issued to Guyer discloses a device consists of a support frame, a mat and a tray with a set of casters that roll on descending ramps attached to the frame. When a golf ball is hit from the mat, the mat and tray deflect downwardly, the mat slides partially off the tray and the tray rolls down the ramps. The mat and tray return to the original position via a tension spring means. 
     U.S. Pat. No. 4,928,966 issued to Miller discloses a device comprises a frame, multiple layers disposed in spaced relation to each other on the frame, and a base attachment. The base attachment possesses guide means and rubber band means to control the sliding forward and back of the frame member. 
     U.S. Pat. No. 4,955,611 issued to Moller discloses a device comprises a mat affixed on top of a bladder filled with gas or liquid and disposed within a base board. The mat and bladder slide forward and optionally downward when struck by a golf club, and are returned by spring means. 
     U.S. Pat. No. 4,913,442 issued to Walker discloses a device comprises a sliding pad mounted in a U-shaped stance pad. The sliding pad is in tongue and groove relation with the stance pad over short length near its exposed end, the rest being free to propagate a wave ahead of a swinging golf club&#39;s head to simulate the feel of taking a divot. 
     U.S. Pat. No. 4,875,685 issued to Ballinger, et al. discloses an apparatus that includes a platform for the golfer to stand on, a main frame connected to the platform adjacent thereto, and an inner frame covered with artificial turf surface and mounted within the main frame. The inner frame pivots forward and then downward in a generally arcuate path when the surface is impacted by the golf club head. The platform can be folded to form a carrying case in which the components can be stored. 
     U.S. Pat. No. 4,387,896 issued to O&#39;Brien discloses a device comprises a hitting surface slidably positioned within a frame and supported by a static surface. 
     U.S. Pat. No. 4,130,283 issued to Lindquist discloses a device with artificial turf secured to a cushioned support that is movable in the direction of the ball flight and compressible when the surface is struck. The movable and compressible portion returns via a spring means. 
     U.S. Pat. No. 3,712,628 issued to Boss, Jr. discloses a device comprises a rigid housing containing rollers which support an endless belt with simulated grass outer surface. A platform beneath the upper portion of the belt pivots about one end and is held against the inner surface of the belt by an elastic means. 
     While these devices may accomplish their stated objectives to some extent, they suffer from one or more of the following limitations: (1) being too complex or too expensive to manufacture to be economically viable; (2) employing materials or involving parts that tend to fatigue or break with repeated use; (3) having an excessively high profile and requiring the golfer to stand on an elevated platform; (4) showing visually distracting elements such as rubber bands, cords and gaps on or around the hitting surface; and (5) requiring extraneous means such as spikes to anchor the device to the ground, which is impractical when the ground is hard surface such as concrete. 
     Co-pending application Ser. No. 11/070,320 by the same inventors of this application discloses a device that is portable and incorporates a base extension which can be slid under a platform for maintaining stability during use. The device comprises a simulated turf surface fitted in a tray slidably positioned on a base. The tray slides forward when struck by a golf club head; means are provided to return it to its original position. The limitation of the device is that it must be disposed adjacent to an extraneous platform. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to a golf practice device having a hitting surface that yields and moves when impacted by the head of a golf club to more accurately simulate what the golfer experiences when hitting a golf ball off natural turf. 
     The present invention provides a golf practice device comprises a platform for supporting the golfer and a divot simulator insert installed in a cavity area within the platform. The divot simulator insert has a base member and a tray rests on top of the base member with a simulated turf surface fitted therein. A cover is also provided to conceal the interior and strengthen the base member. When a golf ball placed on the simulated turf surface is struck by a golf club, the force imparted to the device sends the tray together with the simulated turf surface sliding forward, thus simulating the feel of hitting off natural turf and taking a divot. Means comprising forward and rearward compression springs fitted over guide rails are provided to control the sliding forward and retraction to their original position of the tray and the simulated turf surface. 
     Another aspect of the present invention provides a golf practice device that reduces club head bounce and lessens stress on the golfer&#39;s wrists and elbows, thus reducing negative reinforcement experienced by the golfer and risk of injury. 
     A further aspect of the present invention provides a golf practice device with a hitting surface that yields and gives way, thus experiencing less wear from repeatedly struck by a club head carrying tremendous force and, therefore, having longer useful life. 
     Yet another aspect of the present invention provides a golf practice device that has a simple construct with few components, is strong and durable, and does not employ materials or involve parts that tend to tear, deform, fatigue or break with repeated use. 
     These and other aspects and advantages of the present invention will become apparent after a reading of the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a perspective view of the preferred embodiment of the golf practice device constructed in accordance with the present invention. 
         FIG. 2  is an exploded perspective view of the golf practice device shown in  FIG. 1  showing separately the platform member and the divot simulator insert. 
         FIG. 3  is an exploded perspective view of the divot simulator insert in accordance with the present invention. 
         FIG. 4  is an exploded perspective view of the carriage assembly component of the divot simulator insert in accordance with the present invention. 
         FIG. 5  is a perspective view of the base member and the carriage assembly of the divot simulator insert in accordance with the present invention, showing the carriage assembly mounted on the base member. 
         FIG. 6  is a bottom perspective view of the cover member of the divot simulator insert in accordance with the present invention. 
         FIG. 7  is a perspective view of the divot simulator insert in accordance with the present invention with the carriage assembly and simulated turf surface in an extended position. 
         FIG. 8  is a longitudinal, side elevational view of the divot simulator insert in accordance with the present invention without the simulated turf surface, and with the carriage assembly in the at-rest position and the vertical portion of the side frame omitted to show the carriage retraction means. The support means are illustrated in their entirety for clarity, even though portions should be obscured by the horizontal portion of the side frame. 
         FIG. 9  is a partial, enlarged view of the divot simulator insert as shown in  FIG. 8 . 
         FIG. 10  is a longitudinal, side elevational view of the divot simulator insert in accordance with the present invention without the simulated turf surface, and with the carriage assembly in an extended position and the vertical portion of the side frame omitted to show the carriage retraction means. The support means are illustrated in their entirety for clarity, even though portions should be obscured by the horizontal portion of the side frame. 
         FIG. 11  is a partial, enlarged view of the divot simulator insert as shown in  FIG. 10 . 
     
    
    
     It is to be understood that like elements are identified throughout the drawings with like reference numerals. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The golf practice device according to the concepts of the present invention and how it functions can best be explained by reference to the attached drawings. As illustrated in  FIGS. 1-11 , the preferred embodiment of the golf practice device  10  comprises a platform member  20  and a divot simulator insert  30 ; the divot simulator insert  30 , in turn, consists of a base member  40 , a carriage assembly  50 , a simulated turf surface  60  and a cover member  70 . 
     Referring to  FIGS. 1 and 2 , the platform member  20  is generally square or rectangular in shape and is substantially similar to many of the commercially available golf practice mats, except for the cavity area  21  that is to receive the divot simulator insert  30 . The platform member  20  preferably consists of a base layer  22  made of a sturdy material, a cushioning layer  23  made of a resilient material such as rubber to provide proper support and stability and bonded to the base layer  22  by any conventional means, and a simulated turf layer  24  made of plastic to simulate grass and bonded to the cushioning layer  23  by any conventional means. It is to be understood that any platform composition that provides adequate cushion and has a non-skid surface that allows the golfer to maintain his footing through a golf swing may be used in an embodiment of the device without affecting its functions. A generally rectangular area is cut out through the cushioning layer  23  to create the cavity area  21  wherein the divot simulator insert  30  is installed. The upper portions of the side walls of the cavity area  21  are further recessed to accommodate the cover member  70  that is detailed below with reference to  FIGS. 3 and 6 . 
     Referring to  FIG. 3 , the base member  40  is rectangular in shape with its longitudinal axis generally aligned with the direction of the line of flight of the golf ball to be struck from the surface of the golf practice device  10 , and has side frames  41  along the length dimension on either side and end frames  42  along the width dimension to increase rigidity. Preferably, one of the end frames  42  has cutouts  43  that coordinate with the dimensions of the carriage retraction means  54  of the carriage assembly  50  that is detailed below. The side and end frames  41 ,  42  preferably are L-shaped to increase the strength and tautness of the base member  40 . The cutouts  43  allow for the disassembly and reassembly of the carriage assembly  50  for cleaning and replacement of parts. Preferably, support means  44  are sited at locations determined by the dimensions of the carriage tray  51  and the carriage extensions  53 . They are provided to support the carriage extensions  53  when pressure is exerted thereon and to ensure that the carriage extensions  53  move on a horizontal plane during use. The support means  44  are L-shaped bars in the drawings, though they may assume differing shapes or sizes without affecting their functions. Mounting brackets  45  are affixed to the bottom of the base member  40  and the side frames  41  at positions determined by the length of the carriage retraction means  54 , and are provided to mount and hold in place the carriage retraction means  54 . On the bottom of the base member  40  between the support means  44  is an anti-friction layer  46  made of a low-friction material such as Teflon®. The base member  40  is preferably made of a metal or metal alloy but can be fabricated with generally any structural material such as metals, metal alloys or plastics, and can be either a single-piece construction or assembled from parts. 
     As illustrated in  FIGS. 3-5 , the carriage assembly  50  comprises a generally rectangular carriage tray  51  with sleeves  52  and carriage extensions  53 , and dual carriage retraction means  54 . Each carriage retraction means  54  further consists of a guide rail  55 , one or multiple forward compression springs  56  and a rearward compression spring  57 , with the compression springs  56 ,  57  generally having the same inner and outer diameters as the sleeves  52 . The guide rails  55  have thread means at the ends for affixing nuts  58 . The sleeves  52  are hollow, generally cylindrical tubes that are affixed to the sides of the carriage tray  51  along the length dimension and positioned toward the aft end. When assembled, the sleeves  52  are fitted over the guide rails  55  and sandwiched between the forward and rearward compression springs  56 ,  57  such that the movement of the carriage tray  51  is controlled by the carriage retraction means  54 . The carriage tray  51  has upstanding edges on all sides. The carriage extensions  53  extend outward from the top of the edges on the forward and the aft sides so that the base member  40  remains obscured when the carriage tray  51  is in an extended position, as shown in  FIGS. 7 and 10 . The maximum distance that the carriage tray  51  is allowed to travel during use determines the dimensions of the carriage extensions  53 . 
     Referring to  FIG. 5 , when the golf practice device  10  is assembled, the carriage retraction means  54  are positioned between the mounting brackets  45  with the guide rails  55  mounted on the mounting brackets  45 . The nuts  58  are attached to secure the guide rails  55  in place. The carriage tray  51  fits between the support means  44 ; the carriage extensions  53  are positioned over and supported by the support means  44 . The carriage tray  51  sits on the base member  40  when at rest and slides forward and back when in motion. The carriage tray  51 , sleeves  52  and carriage extensions  53  are preferably made of thermoplastic and can be either a one-piece construction or assembled from parts. In an alternate embodiment, the carriage tray  51 , and optionally the sleeves  52  and carriage extensions  53 , and the base member  40  are fabricated with filled and alloyed plastic composites possessing performance qualities such as: improved abrasion-resistance, lower static and dynamic friction, higher compressive strengths and improved creep resistance. When both the base member  40  and the carriage tray  51  are fabricated with such plastic composites, they are to be made of dissimilar polymers to ensure low coefficient of friction and thus may eliminate the need for the anti-friction layer  46 . 
     As illustrated in the drawings, the simulated turf surface  60 , which may be made of any of the commercially available artificial turfs that are made of sturdy plastic and used for golf practice mats, is fitted inside the carriage tray  51  and preferably extends slightly above the top plane of the carriage tray  51 . The simulated turf surface  60  may be adhesively bonded to the carriage tray  51  or, preferably, removably affixed to the carriage tray  51  with attaching means such as hook-and-loop fasteners. When the simulated turf surface  60  is removably affixed to the carriage tray  51  in an embodiment of the present invention, it can be replaced when worn and different surfaces may be produced to simulate various golf course conditions such as rough fringes and uneven lies for the golfer to practice different shots. 
     Referring now to  FIGS. 3 and 6 , the cover member  70  consists of a cover plate  71 , a frame member  72  and preferably a protective surface  73 . The cover plate  71  is generally rectangular in shape and slightly larger in dimensions as the base member  40 . The center portion is cut out to expose the simulated turf surface  60  and portions of the carriage extensions  53 . The frame member  72 , each segment having an inverted-L profile, extends down vertically from the underside along the circumference of the cover plate  71 . When assembled, the frame member  72  fits snugly around the outer perimeter of the base member  40 , and interlocks with the side and end frames  41 ,  42 . The frame member  72  is removably attached to the base member  40  by any suitable conventional means such as screws, and is provided to strengthen the base member  40  and reduce or limit flexing when the device is in use. The flanges of the cover member  70  fit in the recessed spaces in the side walls of the cavity area  21  so that the divot simulator insert  30  can be fastened to the platform member  20  by any conventional means such as screws. In the preferred embodiment of the present invention, there is a protective surface  73  having the same dimensions as the cover plate  71  that is made of a resilient material and bonded to the top of the cover plate  71  by any suitable conventional means. The protective surface  73  is provided to help dissipate and absorb the impact force when the club head strikes the cover member  70  instead of the simulated turf surface  60  in the event of a missed hit. 
     In use, the golfer places a golf ball on the simulated turf surface  60  and takes a swing with a golf club. Referring to  FIGS. 8-11 , when the club head impacts the device, the force imparted to the carriage tray  51  compacts the forward compression springs  56  and moves the carriage tray  51 , together with the simulated turf surface  60 , forward as directed by the guide rails  55 , thus simulating the feel to the golfer of striking a golf ball off natural turf and taking a divot. When the resistance from the forward compression springs  56  exceeds the forward force, the carriage tray  51  and the simulated turf surface  60  are then returned to their original position. Rearward compression springs  56  are employed to absorb the retraction force and reduce shock to the aft end of the device. The sliding forward of the carriage tray  51  and the simulated turf surface  60  also reduces club head bounce and lessens stress on the golfer&#39;s wrists and elbows, allowing the golfer to correctly practice his golf swing and decreasing risk of injury. 
       FIG. 1  illustrates a platform member  20  and divot simulator insert  30  configuration suitable for a right-handed golfer; however, the divot simulator insert  30  can be detached from the platform member  20 , rotated 180° horizontally and reinstalled for use by a left-handed golfer. 
     To conclude, with respect to the above description, it is to be understood that the optimal dimensional specifications for the parts of the invention, including variations in number, size, shape, form, placement, material and the method of fabrication and assembly, are deemed readily apparent to persons skilled in the art upon a reading of the foregoing description, and all equivalent specifications to those illustrated in the drawings and detailed in the description are intended to be encompassed by the present invention. 
     Further, it will be obvious to those skilled in the art that various modifications and revisions can be made to the embodiment shown herein without departing from the spirit and essential characteristics of the invention. It is therefore intended by the appended claims to cover any and all such modifications and revisions within the scope of the present invention.