Hi,
bei Black&Decker findet man folgendes :
1961 – 1962 – Black & Decker bringt die erste Akku-Bohrmaschine der Welt auf den Markt. Sie wird mit Hilfe eingebauter Nickel-Cadmium-Zellen betrieben. Ein Akku-Rasentrimmer und vier weitere Akku-Bohrmaschinen für den industriellen Bedarf folgen 1962.
Robert H. Riley Jr.
Invented first cordless drill for Black & Decker in 1961; developed tools for early space programs
Robert Riley never knew what would happen when he tested battery packs for the first cordless drills in his lab at Black & Decker, so he built a special room to contain the occasional explosions. Nicad battery technology was in its infancy in 1960 when Riley experimented with portable power, so he had to improvise. He created four-cell packs consisting of half-sections of D-cell batteries held together with plastic shrink wrap.
He'd hook them up, max them out, and see how much power he could generate with his DC motors.
These days it may be hard to imagine a world without cordless tools, but the motivation behind Riley's research stemmed from the day's demographics. Aluminum storm window installation was one of the biggest markets for contractors in the late 1950s and early 1960s. A contractor would typically show up at a home during the day, plug his tools into a porch lamp adapter, and ask the housewife to turn on the light switch. Then the demographics changed and women entered or re-entered the job market. Homes were vacant during the day, and nobody was there to turn on the power for contractors. Battery power seemed to be the answer, and cordless tools got off to a fairly inauspicious beginning.
Riley faced a tough challenge. In 1960, 120-volt, professional-grade drills put out 200 to 250 watts, Riley's first 4.8-volt cordless drills could only produce 10 to 20 watts, so he employed new techniques to make his battery-powered tools as efficient as possible. He made the brushes out of silver graphite, designed a 12-to-1 gear reduction to increase torque and reduce gear loss, used a 64-pitch gear with very fine teeth, and reduced the armature pinion's diameter to 1/8-inch. He also made the rotor out of silver graphite to reduce voltage drop on the comutator, and wired the switch contact with flexible wire so he only needed one stationary contact.
In 1962, Riley filed for a patent on a heavier duty ½-inch drill for industrial use. It had two handles and each housed a battery pack. Early test results proved the tool could drill 567 3/16-inch diameter, 2-inch-deep holes–or run continuously for one hour and 16 minutes–on one charge. Riley's patent application clearly set the stage for today's cordless tool designs, stating the intent that the invention produce, " ... the same output torque as that of a conventional ½-inch electric drill." Riley received a patent for the drill in 1965.
By the late 1960's Riley had doubled the tool's power output to 35 to 40 watts. His research took an unexpected turn when Martin Marrietta contracted with Black & Decker to design tools for the national space program in the mid-1960's. The first tool Riley helped develop was a zero-impact wrench for the Gemini project. The tool allowed an astronaut to spin bolts in zero-gravity without spinning himself. And then came the Apollo moon program. Black & Decker developed a cordless rotary hammer for the mission; it had hollow core-sample drill bits and could operate at extreme temperatures and in zero-atmosphere conditions.
Cordless tools didn't become widely popular until the 1980s, but Robert Riley stands near the top of the Hall of Fame list for his inventions and the way they changed the tool industry forever.
Gruß, hs