Golf clubs are dynamically tested and matched with other clubs by measuring and recording angular velocity and centrifugal force along the axis of a club shaft as the club is swung on an arcuate path in a manner closely duplicating an actual golfer's swing. The club handle is clamped to a linear slide carried by a rotary slide housing having an angle of inclination approximating the lie angle of a golf club during use. Adjustable power rotational drive means swings the club and centrifugal force developed at a given angular velocity of the club displaces the linear slide to activate associated hydraulic devices which measure and record centrifugal force along the club shaft axis in relation to angular velocity of the club. Club weights are then added or removed until the desired angular velocity and centrifugal pull are achieved.
A dynamic inertial balancing system (10) uses a shaft (20) mounted to a base (16). A motor (46) or pulley system (42) imparts rotational torque on the shaft. A swing arm (18) is coupled to the shaft and moves through an arc in a horizontal plane in response to the rotational torque. A golf club is mounted to the swing arm. A timer (38) records the time for the swing arm to traverse the arc. The system balances the golf clubs within a set by measuring their moments of inertia. Each golf club is placed on swing arm 18 and the time is measured for the each golf club to complete the swing arc. If torque is constant for all clubs, then by comparing the moments of inertia, i.e. by comparing the time for each club to complete the swing arc, the club set can be balanced.
A golf bombarding testing machine, which is mainly composed of a golf shooting apparatus, a club holding device, a ball-head holding device, a vibration-reducing device, a ball cage and a machine frame. By the club holding device or the ball-head holding device to fix the club or the ball-head, and by the application of the golf shooting apparatus to shoot out a golf which then hits the ball-head of the said club will reach the double functions of quick test for the ball-head or the connection strength between the club and the ball-head. Furthermore, by the installation of the vibration-reducing device, may greatly reduce the club's vibration caused by the hit on the ball-head and conduct the next test of hitting as soon as possible to increase the number of test in an unit time period.
An apparatus for determining the torsional stiffness of a shaft comprises a rigid frame having a collet for securing one end of the shaft to be measured the rigid frame. A second collet secures the opposite end of the shaft to an inertial weight, which is supported for rotation by a separate bearing so that the inertial weight introduces no axial load in the shaft being measured. The inertial weight has mounted to it a biaxial accelerometer, optical gate or other electronic means for measuring the torsional frequency of the shaft/weight combination. When the inertial weight is displaced from the initial static position and released, the inertial weight oscillates about its center of mass under the urging of the torsional stiffness of the shaft. A computer is programmed with the mass moment of inertia of the inertial weight and therefore is able to solve the differential equation of motion for the torsional spring constant of the shaft based on the frequency of oscillation.
