Tennis Racquets


In collaboration with our partner Division, LLC, we have designed a new type of tennis racquet, the “equalizer”, that represents the first fundamental innovation in tennis since the large-head racket was introduced in 1976. All current rackets have nearly identical oval shapes and therefore look and play essentially the same.  They provide strong and light frames, but convey very limited power and control, and have a small sweet spot. They require a choice between power (low string tension) and control (high tension).

The Equalizer will change all this.  Because of it’s approximately rectangular face, all the main strings have approximately the same length and can be independently tensioned to vibrate with the same frequency.  All the cross strings also have approximately the same (shorter) length, and with suitable string material can be tensioned to vibrate with the same frequency as the mains.   Equalized vibration frequency of all strings produces greater power and a sweet spot (SS) at least four times larger.  Also, the Equalizer’s large axial moment of inertia reduces the error from off-axis hits, and the equal string vibration frequencies reduce the error from hits on adjacent strings.

The Equalizer’s optional integrated lockable grommets enable independent stringing and exact tensioning of each string, enable equal frequencies without equal string lengths, enable lower tensions on (shorter) cross and outer strings, and therefore create an even larger SS.  They also enable easy courtside re-tensioning or replacement of individual strings, and enable playability even with broken strings. 

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Baseball/Softball Bats (Yip grip)


Our invented sting-stop baseball bat consists of two parts, the barrel-throat-stem and the handle.  The barrel is conventional, but, instead of tapering into a conventional hollow handle, the throat terminates into a relatively thin solid rod.  The handle part is a hollow circular tube with an outward taper at the end facing the barrel.  An elastomer is molded to fill the space between the rod and the tube.  The dimensions of the rod, and the elastic modulus of the elastomer, are chosen such that the transverse waves, which propagate down the bat after impact with the ball, are absorbed in the elastomer and are not transmitted to the outer handle.

Oscilloscope readings (amplitude verses time) of vibrations on bat handles show that the transverse waves created by a hit ball on a conventional bat handle are undiminished during the first 0.1 seconds after impact, whereas the wave created by the same impact on the sting-stop handle during the same time interval decreases by a factor of 15.  During the first 0.5 seconds after impact, the wave on the conventional handle remains undiminished in even this large time interval, whereas the wave on the Shock-Block handle is completely dissipated after 0.25 seconds.  The dramatic sting attenuation properties of the Shock-Block technology are clearly demonstrated.

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Golf putters


If a correctly swung putter head makes contact with a golf ball at the sweet spot (the point directly in front of the COM), the ball will rebound at the intended speed and in the intended direction.  If the impact is not at the sweet spot, the ball will rebound with a decreased speed and in a deviated direction.  The larger the putter head MOI, the smaller are these speed and direction errors.  We have designed a class of golf putter heads characterized by having extremely large moments of inertia (MOI) for a given weight and size. (This product was developed in collaboration with our partner Division, LLC.) These MOI values are more than double those of any putter head on the market.  We achieve these large MOIs in four novel ways. 

  •  The putter head consists of two to four relatively heavy "load" elements placed in locations as far as possible from the putter head center of mass (COM). 
  •  The shapes of these elements are chosen to increase the MOI.
  •  The dimensions of the load elements are chosen to increase the MOI.
  •  The weights of the load elements are determined, by mathematical optimization calculations, to maximize the MOI.

We have also designed putter heads that cause a struck ball to immediately begin a pure rolling motion, thus eliminating the erratic sliding and skipping that usually occurs during the initial phase of motion.  The rolling is created by forward pointing teeth on the face of the putter, and by the forward loft of the face. 

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Football helmets


It has been widely realized during the past 20 years that the collisions experienced by participants in contact sports and other potentially injurious endeavors are often strong enough to give rise to mild traumatic brain injuries (MTBI) such as concussions. Although more protective helmets have been introduced and used by participants in sports and other endeavors, the frequency of MTBI has remained alarmingly high.

In response to the MTBI epidemic, we have designed, constructed, and evaluated a new type of football helmet that provides increased protection to users.(This product was developed in collaboration with our partner Division, LLC.) This helmet dissipates a significant amount of the incident kinetic energy arising from an impact, thus reducing the force and torque applied on the helmet, and spreading out the force transmitted through the helmet onto a user’s head. We have constructed a partial helmet prototype that incorporates our energy-dissipating elements, and have used conventional and original testing equipment to demonstrate the significantly increased user-safety that this prototype provides.  Compared to the highest rated available helmet, our prototype helmet is seen to significantly reduce the applied force and extend the impact time.

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