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Designer's Corner
John Lewis, Regional Editor -- Design News, September 17, 2000
Molded-in LEDs
Shock, vibration, corrosive fluids and gases, mud, dust, and temperature extremes—these are just a few of the reasons most motorbike marker lights never make it to maturity. A patented concept for the manufacture of marker lights uses a matrix of light emitting diodes (LEDs), a flexible wiring harness, and an encapsulating shell of impact-absorbing polyurethane thermoplastic. The design is said to exceed SAE J1889 June 99 LED lighting standards for ground vehicle applications. They can also be operated at a 100% duty cycle, at LED maximum rated drive currents without self-heating problems. Mean time between failure is better than 100,000 hours or eleven plus years of continuous duty. Other claimed benefits include:
80% more energy efficient than incandescent lighting
Tested to work submerged in water to a depth of 100m
Able to survive extreme impact, continuous vibration, and abrasive environments
Operates at temperature extremes from -40 to 100C
Fast turn-on times (less than 100 nanoseconds)
Can operate from ac and dc power sources as well as customer selected input voltage
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Designed for high-volume production using automated manufacturing methods, Polyflex marker lights can be molded from polymers colored with tints and diffusants to provide added styling. |
Both the LEDs and wiring harness are coated with a polymer adhesive before molding to promote rubber-tearing bonds between the polyurethane thermoplastic and the wiring harness/LEDs. Insert injection molding completely seals the mounted LEDs. Proper thermoplastic selection ensures an index of refraction equal to traditional lens materials such as polycarbonate, as well as resistance to UV exposure. Two polymer-coated stainless-steel power cables with molded-in strain reliefs complete the package.
Tom Selkee, Polyflex Lighting Inc., 1434 N. Mills Ave., Claremont, CA 91711; Tel: (909) 621-9585; E-mail: tselkee@yahoo.com .
Variable hydraulic pump
Vanes contact a flexible band that's free to revolve. If the band is a circle, there is no gain or loss of fluid volume in any of the chambers. Pressurizing one pair of opposing pistons forces the band into an ellipse, altering the relative volumes of adjacent chambers.
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Above, opposing port pairs drive two separate outputs for differential control. Below, pressurizing one set of radial pistons creates pressure and suction ports. |
Excess fluid entering the first and third quadrant chambers establishes the pump's pressure ports. Fluid shortage in quadrant chambers two and four sets up the suction ports. The result, when connected to an external fixed-displacement hydraulic motor, is a hydrostatic loop. By varying the radial positions of the pistons, fluid displacement can be fully controlled from zero to maximum in any increment. This feature, in combination with an external hydraulic motor, permits several drive possibilities:
Straight line motion. One hydristor driving two hydraulic motors at the same rate.
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Turning. Unequal, but controlled flow to the motors for different wheel speeds and turning radii.
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Spin. Reversing wheel rotation on one side of the vehicle with respect to the other turns a vehicle about its vertical axis.
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All-wheel performance. Connecting an additional hydraulic wheel motor in each front wheel in series with the rear wheel circuits turns front and rear wheels on a given side at the same rate.
Tom Kasmer, Hydristor Corp. ,Box 779, Johnson City, New York 13790; Tel: (607) 770-9684.
