Designer's Corner

Frictionless damper

Developed for defense and aerospace applications, this hydraulic damper exhibits internal friction less than 2% of rated load. The design uses labyrinth seals between the shaft and cylinder that interfere minimally with shaft motion. Fluid that leaks past the seals is contained in metallic bellows at either end of the cylinder, and this excess fluid returns to the opposite side of the cylinder through a bore within the shaft.

The damper also features variable response depending on shaft velocity. A spring-loaded valve on the shaft piston opens at a predetermined velocity relieving excess pressure and preventing damage. Their inherent safety may make the dampers attractive in applications where replacement may be difficult or expensive.

Douglas Taylor, Taylor Devices, Inc. , 90 Taylor Dr., P.O. Box 748, North Tonawanda, NY 14120, (716) 694-0800.


Flexible fixture

Visit any manufacturer of electronic components and you'll find assemblers or re-workers struggling to solder multi-pin connectors. This simple fixture ends the gymnastics. A draw-bar collet headstock holds the wire while a snap-fitting tailstock holds the multi-pin terminal. A single geared shaft coupled to the headstock and tailstock rotates them synchronously, simplifying assembly operations.

Edward Johnson, Welch Allyn , 4619 Jordan Rd., Skaneateles Falls, NY 13153, (315) 685-4285.


Free-rail railroads

Although the current scheme of continuously welded tracks improves rail-travel smoothness, it requires ongoing maintenance to repair the ravages of temperature changes and imperfect alignment. Laying discontinuous sets of alternating-gauge tracks for cars with twin pairs of wheels would eliminate those problems and may help to accelerate the current economic and ecologic trend back to rail travel.

The inventor of this arrangement estimates that modifications to existing cars should come to a fraction of their initial cost. The design will speed operations between roads with differing gauges, a common occurrence outside the U.S. The patent is available for license.

Alan R. Newton , 67 Bluebird Ave., East Wareham, MA 02538, (508) 295-2376.


Smart tags

Electronic "embedded fingerprints" developed for keeping track of nuclear missiles may soon facilitate warehouse and point-of-sale inventory control. Unlike read-only RF ID systems, the tags currently under development by the Pacific Northwest Laboratory and Lawrence Livermore Laboratory could be programmed with lot data by a manufacturer and inserted into items or containers for later reading by warehouse personnel or retailers.

The needle-sized tags contain an RF-coil, capacitor, and custom IC. Radio-frequency energy emitted by a portable reader and collected by the coil charges the capacitor, enabling IC reading or writing.

Sharon Brown, Pacific Northwest Laboratory , 901 D St. SW, Suite 900, Washington, DC 20024-2115, (202) 646-5265.


Insulative cushion

An extruded-urethane core surrounded by an elastomeric cover produces a low-cost shock-absorbing shell. V-shaped elements within the shell provide resilient support while encapsulating insulating air. Initial applications for the Sigma cushion include bathtub mats or liners that may help prevent thousands of injuries yearly. As a bonus, the cushion reduces water-temperature loss in a typical tub to 4F/hr. Tough and re-usable, the cushion may have other applications in load and shock isolation.

Milton Weber, Technology, Inc. , 20655 Audette, Dearborn, MI 48124, (810)

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