Get a Grip: Flexible basket-shaped
gold-plated femal contacts provide easy-to-mate, long-life, low-resistance
CONTACTS GIVE RUGGED CONNECTOR LONG LIFE
The female spring-steel contacts inside the minifast® cordset connectors are progressive-die-stamped with their contact surfaces selectively gold plated. The result is a contact that is economical to make, easy to connect, and has lower resistance to allow higher currents.
Conventional cordset contacts are machined brass bushings, slotted to provide expansion and grip for the male connector. Machining is more expensive than die stamping, and brass, being less elastic than spring steel, is more prone to fatigue failure. And if misaligned axially, the male contact can jam in the contact slot, deforming it.
Holding the stamped contacts in place during fabrication of the cordset was a challenge for Turck design engineers. When the molded plug material that surrounds and holds the contacts cools, it shrinks, which tends to pull the contacts back from the front face of the connector. Their solution: A barb added to the contact fits between the two pieces of the contact carrier's front face. This restraint retains the contact position relative to the face when the rest of the connector body is molded around it, and then cools.
Contact:Dave Lagerstrom, TurckTel (800) 296-5533; Fax (763) 553-0708; firstname.lastname@example.org://rbi.ims.ca/3851-500
MOTOR TAILORED FOR MAXIMUM MACHINING SPEED
Engineers gave the IndraDyn L linear motor more iron laminations for the number of copper windings (which themselves are more efficiently wound with tighter turns) to provide a higher ratio of iron-to-copper compared to conventional linear motors. The reason: For peak current surges, the iron core won't magnetically saturate and thus it produces a higher peak force.
Conventional motors use a large number of current-carrying windings for maximum continuous force. But when current is boosted to a peak, the smaller core can saturate, causing the force to level off.
The maximum peak force/maximum continuous force of the IndraDyn L with more iron is greater than 3:1, compared to 2:1 for a typical linear motor, according to Douglas Bruss, Bosch Rexroth product support engineer. This translates into higher acceleration for a given burst of current. The motor is targeted at machine tool applications, where a cutting tool needs to move swiftly between cuts, reducing costly nonproductive time.
Contact:Douglas Bruss, Bosch RexrothTel (847) 645-3712; Fax (847) 645-6210 email@example.com://rbi.ims.ca/3851-501
Unsaturated: A high ratio of iron
laminations to copper windings ensures the IndraDyn L permanent magnet
linear motor doesn't magnetically saturate at high currents, producing a
higher peak force.
PLATABLE THERMOPLASTIC CUTS STRESS
Engineers turned to recently developed LCP and PPA thermoplastics that can be metal plated to produce these Coax Surface Mount Interconnect Devices (CoSMIDs) for 75-ohm connectors used in telecom applications. The devices can be molded into various port configurations and selectively plated for specific electrical contact layouts.
The thermoplastics can also take the heat of reflow soldering, upwards of 245C (473F), during surface-mount attachment of the CoSMIDs onto a circuit board. The plastic connectors have a thermal coefficient of expansion close to that of FR4 glass cloth/epoxy circuit board material (19.7 ppm/C), as opposed to metal-bodied connectors, aluminum for example (23.8 ppm/C)—that expand and contract more. The result is less thermal-shock induced stresses in the contacts during soldering as well as when operating, resulting in fewer instances of contact lead cracking and open circuits.
Engineers designed the connector family with a flat top to aid suction-cup end effectors on pick-and-place machines. The contact pads are also formed as part of the flat, molded surfaces, having high coplanarity for good bonding to a PCB. By combining multiple ports in a single connector, the designers gave the connectors a large surface area for plating solder pads, further improving connection electrical and mechanical integrity.
CoSMID minimum costs in quantity are $4 for a two-port connector, $5 for the three-port version, and $8 for the four-port type.
Contact:George Blazas, ITT Industries, CannonTel (860) 945-0206; firstname.lastname@example.org://rbi.ims.ca/3851-502
Thermal Compatibility: Capable of being
plated, the thermoplastic housing on these coaxial connectors has a
thermal coefficient of expansion comparable to circuit board materials.
This compatibility mitigates stresses that might crack leads during reflow
soldering or in use.
VANES COUNTER ELBOW VORTEX
When flow in a pipe travels through an elbow, the turning induces a spinning vortex motion and may cause turbulence in the fluid. Such change in laminar flow can cause noise, vibration, instability, and cavitation in pumps, flow meters, valves, etc., typically within 10 pipe diameters of the elbow. Vortex-induced elbow erosion is also a problem with two-phase flows.
The patented Cheng Rotation Vane (CRV)® offsets these elbow effects. The CRV is a set of six longitudinal vanes with a slight twist on their downstream side, welded inside a cylindrical body whose length is roughly equal to its diameter. This body is in turn welded or flange mounted to the upstream side of an elbow. The rotation induced by the CRV counters that from the elbow, producing a more uniform velocity profile.
Engineers developed the compact six-vane configuration after varying length, angle, and number of vanes to try and trade off vortex generation, flow blockage, and ease of manufacture. They found a three-vane configuration was more effective in flow turning, but had to be longer to work and were harder to build. An eight-vane design was shorter, but had too high a pressure drop and wasn't easy to make either.
CRVs come in two types: With vanes angled at 22 degrees for long radius elbows (inner pipe turn radius is 1.5X inside diameter) and 33 degrees for short-radius ones (inner turn radius equals diameter).
Contact:Richard Golomb, Cheng Fluid Systems Inc.Tel (650) 941-9290 ext. 103; Fax (650) 947-9273; email@example.com://rbi.ims.ca/3851-503
Vortex Generator: The Cheng Rotation Vane
produces vorticity in pipe flow ahead of an elbow, which then counters the
spinning developed as the elbow turns the fluid. The resulting flow is
more uniform, mitigating cavitation and erosion in downstream equipment.