Hydraulically operated force pump

Water fills the line to the surface and outlet, as well as the volume above the pump's upper piston, the connecting tube and upper check valve, and the volume below the lower piston down to the lower check valve.

Initially, the user adjusts spring tension to keep the piston in its topmost position. To start pumping, the user applies pressure to the water at ground level.

Pressure transmitted by water acts on the larger upper piston. Force transmitted trough the connecting tube reaches the lower piston, which is smaller than the upper piston. Because of the lower piston's smaller size, pressure beneath the lower piston exceeds that above the upper piston. Consequently, water flows upward through the connecting tube and upper check valve into the volume above the upper piston.

Releasing pressure at the surface allows the spring to return the piston assembly to the top position, and atmospheric pressure refills the volume below the lower piston through the lower check valve. The net result is a gain in fluid above the upper piston with each downward stroke. The amount gained equals the volume of the lower piston's displacement.

James R. Ranz, 68 Mitchell Road, Wilmington, OH 45177.

Dual-axis, single-plane positioning

Two single-axis dc linear motors drive the NORMAG L-Stage in the X and Y axes. High-stiffness, magnetically pre-loaded air bearings couple the motors to a shuttle. Motors and shuttle float on air bearings above a flat base plate.

Single-axis position encoders on the motors enable a digital controller to position the shuttle within one micron over the full X-Y travel.

Travel can range from 3 x 3 inches to 8 x 8 inches with continuous forces at 100% duty cycle ranging from 15 to 50 lbs.

Ted Scheumann, Northern Magnetics Inc., 25026 Anza Drive, Santa Clarita, CA 91355, (805) 257-0216.

Pop-up door lock

The protruding lip on the door-mounted plate prevents downward movement of the locking bar until the user almost completely closes the door. This arrangement prevents intruders from reaching inside the door to bypass the lock.

When the lock is not in use, a foot-operated push-down latch holds the locking bar in place. To ensure ruggedness and security, the installer bolts or screws the door lock to the building's subflooring. Lock components can be made from brass, steel, or any other material capable of withstanding a brute-force attempt at entry.

Jeffrey A. Harvey, 19 Guildwood Drive, Fall River, Nova Scotia, Canada B2T 1J6, (902) 860-0533.