Abstract:
Improved push button release for a centrifugal golf swing indicator which releases the indicator weight when the push button is depressed, and resets the golf swing indicator for the next use when the release button is released. Further improvements include a pair of opposed C-clamp attachments and an indicator for the indicator weight.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefits of prior filed, co-pending provisional application Ser. No. 60/103,637 filed Oct. 9, 1998. 
    
    
     This invention relates generally to an accelerometer device for measuring the swing imparted to a golf club, and more particularly to an improved golf swing indicator especially adapted for attachment to a golf club shank with improved resetting of the device after measuring the swing. 
     BACKGROUND OF THE INVENTION 
     A basic type of indicating gauge responsive to circular or angular velocity for attachment to sports equipment is shown in U.S. Pat. No. 2,780,098. There an elongated housing contains a rotatable shaft with ratchet teeth and a slidable indicator with a pawl engaging the ratchet teeth to hold the indicator against the biasing force of a compression spring. A separate weight is slidable along the shaft and restrained from movement toward the indicator by a tension spring. The housing is attached to a piece of sports equipment, such as a tennis racket . Centrifugal force of the swing causes the weight to slide along the shaft and displace the indicator which, in turn, is retained by the pawl and ratchet teeth, while the weight returns to its former position. A push button release with pin and cam slot cause the shaft to rotate and return the indicator. 
     A later disclosed golf swing indicator is shown in U.S. Pat. No. 4,270,753 in which the slidable indicator and slidable weight are combined into a single member rather than separate members. The release mechanism employed a torsion spring to resist the turning of the shaft by an external knob, so as to release the pawl from the ratchet teeth and allow the combined weight and indicator member to return to its zero position. C-clamps with thumb screws were attached to the housing for enabling attachment to the shank of a golf club. 
     A still later golf swing indicator is disclosed in U.S. Pat. No. 4,684,133, in which a detent structure acting between the shaft and the housing was substituted for the torsion spring of U.S. Pat. No. 4,270,753. This requires using an external knob to first rotate the shaft in one direction to release the indicator and then in the other direction to reset the pawl on the ratchet teeth. While this eliminates a torsion spring, it results in a cumbersome resetting procedure. The C-clamps with thumb screws also represent an attachment method which has the possibility of damaging the golf club shank by over-tightening the thumb screws. 
     It would be desirable to have an improved release mechanism assembly suitable for a golf swing indicator of the type described. 
     It would also be desirable to have an improved push button release mechanism for a golf swing indicator of the type described, which automatically releases and resets the indicator after each use with one push. 
     It would also be desirable to have an improved structure for attaching the indicator housing to the shank of a golf club. 
     It would also be desirable to have an improved slidable indicator weight and spring pawl attachment. 
     SUMMARY OF THE INVENTION 
     Briefly stated the invention comprises improvements in a golf swing indicator for attachment to a golf club shank, the golf swing indicator being of a known type having an elongated housing, an elongated shaft rotatable within the housing, the shaft having a row of teeth and a smooth section alongside the row of teeth, a combined indicator and centrifugal weight (indicator weight) slidable along the shaft, a spring pawl mounted on the indicator weight and adapted to engage the teeth when the shaft is rotated to a first position and to slide on the smooth section of the shaft when the shaft is rotated to a second position, a first spring biasing the indicator weight toward a first end of the shaft. 
     An improved release mechanism for the above known golf swing indicator comprises a cylindrical bushing mounted on the first end of the elongated shaft, the bushing having a radial cam pin integral therewith, a release button having a cylindrical bore arranged to slidably and rotatably receive the bushing, and having a cam slot receiving the cam pin, a release button housing mounted in the main housing arranged to slidably receive the release button and having means preventing rotation of the release button, the cam slot being arranged to rotate the cam pin and shaft from the first shaft position to the second shaft position when the release button is pushed by an operator, and a release return spring (second spring) adapted to return the release button when it is no longer being pushed, so as to cause the cam slot to rotate the cam pin and shaft from the second position back to the first position. 
     An improved attachment for the golf club swing indicator comprises a pair of resilient C-clamp members attached to the housing and adapted to receive a golf club shank, the C-clamps being oriented in opposite lateral directions so that the golf club shank is engaged by twisting the swing indicator housing. The C-clamps include retaining buttons holding the shank against cushion pads mounted in the main housing. 
     An improved spring pawl and indicator weight attachment structure comprises a slot in the spring pawl and a projection on the indicator weight which extends through the slot to fix the location of the pawl, as well as to serve as a visible indicator mark to match against indicia on the main housing indicating the effectiveness of the golf swing. 
    
    
     DRAWING 
     The invention will be better understood by reference to the following description, taken in connection with the accompanying drawing, in which: 
     FIG. 1 is a perspective view of the golf swing indicator attached to the golf club shank, 
     FIG. 2 is a top plan view of the golf swing indicator, 
     FIG. 3 is the same top plan view of the golf swing indicator with portions of the cover removed and partly in section to disclose the indicator weight and release mechanism, 
     FIG. 4 is a side elevational view with portions of the housing removed to disclose the release mechanism, weight indicator and attachment clamps, 
     FIG. 5 is an end elevation view detail of one of the attachment clamps, 
     FIG. 6 is an enlarged top plan view of the indicator weight after displacement of the indicator weight and before the release button is pressed, 
     FIG. 7 is the same view as FIG. 6, after the release button is pushed to rotate the shaft and release the indicator weight, and 
     FIG. 8 is the same view as FIGS. 6 and 7 after the release button has been released to reset the mechanism. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 of the drawing, a golf swing indicator shown generally as  10  is adapted for attachment to a shank  12  of a golf club near the head of the club. The golf swing indicator comprises an elongated housing  14  with an indicator weight to be described, which is subjected to centrifugal force of the golf club. The housing has indicia  16  marked on one face thereof to indicate the speed of the club swing and/or the distance traveled by the ball, and a release button  18  which resets the mechanism. The indicia are inverted so that they can be read by the operator. 
     Referring to FIG. 2 of the drawing, golf swing indicator  10  is illustrated in greater detail in the plan view, with indicia  16  in a readable position. Resilient C-clamps  20 ,  22  extending laterally in opposite directions from housing  14  serve to attach the housing  14  to the shank  12 . One of these may be seen in FIG. 1, the other one being obscured from view. 
     A spring-biased indicator weight  24  with an indicating mark  26  may be seen through a transparent window  25 . As in known prior art golf swing indicators, indicia  16  may be marked off in an arbitrary scale indicating club head speed and may also be marked off in yards theoretically achieved by the golf ball when struck by the golf club. 
     Referring to the partial cross section views of FIGS. 3 and 4 of the drawing, many of the details of the golf swing indicator  10  are similar to those of prior art devices mentioned in the Background of the Invention, but will be described for completeness of the description. 
     An elongated housing  14  of plastic material comprises a bottom wall  14   a , side walls  14   b ,  14   c  and an end wall  14   d . The top of the housing is closed by a transparent cover piece  15 , on which the indicia are inscribed or provided using a decal (FIG.  2 ). An elongated shaft  28  extends through the center of housing  14  and is rotatably mounted therein. One end of the shaft  28  is supported in an internal bearing  30 . The other end of shaft  28  is inserted into a special bushing  32 , which is rotatably mounted in a cylindrical bore  18   a  of the release button  18 . 
     The elongated shaft  28  includes a row of teeth  34  extending along the shaft and a smooth section  36  alongside the row of teeth. The indicator weight  24  is adapted to slide along the elongated shaft  28  inside the housing, and is biased toward the right hand side of the drawing by means of a compression spring (first spring)  38 . The spring constant of compression spring  38  and the weight of the indicator weight  24  are carefully selected with respect to one another so that a known acceleration due to centrifugal force will move the indicator weight  24  (toward the left hand side of the drawing) by a predetermined linear displacement. 
     A spring pawl  40  includes a tip end which engages teeth  34  in a first rotatable position of shaft  28 . This prevents the return of the indicator weight  24 . When shaft  28  is rotated to a second position, the tip of pawl  40  engages the smooth portion  36  of shaft  28 . This allows the indicator weight  24  to move to the right under the force of compression spring  38  until it reaches a stop  42  incorporated in housing  14  for this purpose. The foregoing details are known in the prior art. 
     The release mechanism assembly will now be described. Bushing  32  is rotatably mounted within the cylindrical bore  18   a  of the release button  18 . Bushing  32  includes a radial cam pin  44  which extends into a cam slot  46  in the side of the release button wall. A release return spring  48  (second spring) is interposed between the end of bushing  32  and the closed end of release button  18 . The release button  18  is slidably mounted within a release button housing  50  which is mounted in the end of housing  14 . The release button has flat sides  18   b ,  18   c , so that it is constrained to move longitudinally in the release button housing  50  without rotating. Therefore, when release button  18  is pressed so that it moves longitudinally to the left, the cam slot  46  requires the radial cam pin  44  to rotate shaft  28 . The rotation is such that the row of teeth  34  is disengaged from the end of pawl  40  to allow pawl  40  to engage the smooth section  36  of shaft  28 . This releases the indicator weight  24  and allows the indicator to reset. Release of the release button  18  enables the compression spring  48  to move the release button in a longitudinal direction, thereby constraining the shaft  28  to return to its previous position. 
     The foregoing sequence of events is depicted in the partial views of FIGS. 6,  7  and  8 . FIG. 6 indicates the indicator weight  24  after it has moved to the left by centrifugal force of the golf swing and held by the ends of pawl  40  pressing against teeth  34 . 
     FIG. 7 illustrates release button  18  depressed against compression spring  48 . Cam slot  46  has caused the bushing radial cam pin  44  to rotate the bushing  32  and shaft  28  to a second shaft position, which releases indicator  24 . 
     FIG. 8 illustrates how compression spring  48  returns release button  18  to its previous position. When this occurs, cam slot  46  causes cam pin  44  to rotate bushing  32  and shaft  28  to their previous positions, thereby resetting the mechanism. 
     Another feature of the invention is the use of the spring pawl attachment as an indicator mark. Referring to FIGS. 3 and 4 of the drawing, spring pawl  40  is of metal and includes a slot  52  on the flat top section of the pawl. The indicator weight  24  comprises a plastic housing with an upstanding rectangular tab  54  of a color distinguishable from that of the metal pawl  40 . The dimensions of the two members are such that the pawl  40  can be snapped in place with the slot  52  fitting tightly over the exposed end of the ridge  54 . This provides a visual indicator to use in connection with the indicia and also holds the pawl to the indicator weight. 
     Another important feature of the invention is the manner in which the housing is attached to the shank. Referring to FIGS. 3,  4  and  5  of the drawing, the resilient C-clamps  20 ,  22  are seen to extend laterally in opposite directions. Elastomeric cushions  56 ,  58  are attached to the bottom wall  14   a  of the housing and arranged adjacent the clamps. Each of the clamps, as seen in FIG. 5, includes a resilient or flexible wall  60  and a connected pressure pad  62  incorporating a hard retaining button  64 . Thus when the golf club shank  12  is pressed against the clamp, it will snap over the retaining button  64  and be held by the resilient wall  60  of the clamp against the cushion  58 . 
     An important feature of the invention is the disposition of the lateral openings of clamps  20 ,  22  so that they face in opposite directions. In this manner, rather than pushing the shank against two clamps facing the same direction, the housing can be applied with a twisting motion resulting in greater ease of attachment than in the previous golf swing indicators.