Abstract: A children's baseball bat with a pressurizable, external hitting zone to selectively control the trampoline effect when a ball is struck by the bat. The hitting zone is provided by expandable tubing wrapped spirally around the barrel of the bat and connected to a manual air pump built into the handle of the bat to increase air pressure in the tubing. A pressure relief valve connected to the tubing allows the user to decrease air pressure in the hitting zone to control the trampoline effect or to decrease the circumference of the barrel.

Abstract: A screen guard is utilized to protect fin coils of a fin-coil heat exchanger of an apparatus such as a heat pump or air conditioner. The screen guard prevents cottonwood seeds and other debris capable of forming a filter from obstructing the air flow over the fin coils. The screen guard comprises a wide mesh screen member and an adhesive attachment strip. The attachment strip may be magnetic so that it attaches directly to a ferrous housing of the apparatus. Alternatively, a VELCRO® fastener strip is fixed to the apparatus and the attachment strip is a complimentary VELCRO® strip which removably attaches to the fastener strip. The screen guard can be repeatedly removed and reattached for cleaning debris from the screen guard. A method of protecting the apparatus includes removing the screen guard for cleaning and thereafter reattaching the screen guard.

Abstract: A concrete saw is provided which utilizes a transmission having both forward and reverse, high and low speed ranges separated by a neutral state. The transmission includes a neutral start switch which prevents the engine from being started, while the transmission is in gear. An automatic parking brake assembly is mounted to the frame proximate the drive wheel. The brake assembly fixedly engages the drive wheel when the ignition switch is turned to the off position, when the battery is disengaged or when the battery is dead. The brake assembly also immobilizes the drive wheel whenever the transmission is shifted to the neutral state regardless of the position of the ignition switch. The system is provided with an override switch to bypass the automatic application of the brake assembly when the transmission is placed in neutral to facilitate winching or otherwise rolling the saw without engine power. Normally, the brake assembly disengages when the transmission is shifted from neutral into gear.