Abstract: A metastable, motion generating squirrel feeder with a pair of coupled, generally V-shaped ribs attracts squirrels with corncobs secured at each rib end. Each rib has a pair of projecting wings symmetrically diverging away from a central vertex. The wings terminate in ends occupying the vertices of a virtual tetrahedron. Notches in the rib vertices enable rib coupling during assembly. Spaced-apart feed holders mounted on the wings each have a fixed bracket and a slidable bracket. Spikes projecting from each bracket towards the other captivate feed such as corncobs sandwiched between the brackets. A mounting ring non-rigidly captivates the vertice region of the ribs, loosely mounting the feeder and suspending it above ground so that the ribs are free to rotate and move in response to squirrels.

Abstract: An electronic alarm and a vending machine equipped with the alarm monitors a plurality of zones by suitable circuitry to detect vandalism and theft. Each zone has a mechanically-triggered sensor that provides an electrical output. The zones comprise a pair of door sensors and a separate, shock sensor. A solid-state logic circuit includes a red and green indicator light, and a loud warning buzzer ultimately triggered by the sensors. A circuit time delay and logic scheme analyzes sensor status, and separate false-alarm prevention circuits insure proper triggering after a predetermined delay. Alarm status is indicated by highly visible green and red status lights mounted on the door. A buzzer sounds in response to sensor activation and circuit logic. A back-up battery that is coupled to the logic circuitry for fail-safe operation includes an automatic recharge system, and dual red and green LED's monitor battery condition.

Abstract: Pans for power finishing freshly placed concrete in which the acoustic impedance of the treating equipment is made substantially equal to the acoustic impedance of the concrete slab being treated. Preferably, a powered, twin rotor riding trowel is provided with a pair of circular finishing pans that are attached to the conventional rotor blades used later in the finishing process. The pans are characterized by an acoustic impedance approximating the acoustic impedance of plastic concrete, thereby optimizing the energy transferred to the concrete. Preferred pans comprise ultra-high molecular weight polyethylene (UHMWPE) plastic. During troweling, the pans are frictionally revolved over the plastic concrete for finishing the surface without prematurely sealing the uppermost slab surface. Through the disclosed troweling method, a highly stable concrete surface results, and delamination is minimized. Alternative troweling uses pans coated with layered impedance matching material.

Abstract: Methods and apparatus for power finishing freshly placed concrete in which the acoustic impedance of the treating equipment is made substantially equal to the acoustic impedance of the concrete slab being treated. Preferably, a powered, twin rotor riding trowel is provided with a pair of circular finishing pans that are attached to the conventional rotor blades used later in the finishing process. The pans are characterized by an acoustic impedance approximating the acoustic impedance of green concrete, thereby optimizing the energy transferred to the concrete. Preferred pans comprise ultra-high molecular weight polyethylene (UHMWPE) plastic. During troweling, the pans are frictionally revolved over the green concrete for finishing the surface without prematurely sealing the uppermost slab surface. Through the disclosed troweling method, a highly stable concrete surface results, and delamination is minimized. Alternative troweling uses pans coated with layered impedance matching material.