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Note added at 5 hrs (2008-12-29 17:36:30 GMT)
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search for "differential coupling" in google or at the US PTO website.

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Note added at 2 days1 hr (2008-12-31 13:37:47 GMT)
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"he coupling collar 84 has similar thread diameters. The aspect of different thread diameters permits the coupling collar 84 to be unscrewed from drill pipe 50 onto drill pipe 52 wherein the coarse threads 92 of coupling collar 84 do not become engaged with the fine threads 90 of drill pipe 52. In this manner, coupling collar 84 can be lowered onto drill pipe 52 until it abutts stop flange 96.

Because the ends of the illustrated drill pipes include threads of different pitch to provide }differential coupling{, the threads 88 and 90 are both either right-hand or left-hand threads. Preferably when pipes are coupled only by the coupling collar 84, the threads will be in the direction wherein the rotary action of the drill tends to tighten the coupling between drill pipes." US4,676,563 (context of threaded pipe couplings)

and

"An instrument for continuously indicating the instantaneous rate of fuel consumption (e.g. in terms of liters per 100 kilometers) during operation of a motor vehicle comprises a stationary speed scale juxtaposed with a movable consumption scale, the two scales carrying relatively inverted logarithmic graduations and being swept by a common pointer driven through a gear train from a speedometer biased by a spring of logarithmic characteristic. The movable scale is magnetically entrained, via a friction coupling, by a flowmeter which is thermostatically controlled to take changes in fuel viscosity due to temperature variations into account; the friction coupling can be manually preadjusted in accordance with the specific weight of the fuel. The pointer and the movable scale are carried by two coaxial disks that coact through a }differential coupling{ with a switch which energizes different signal lamps according to whether, at a given speed, the rate of fuel consumption is normal, subnormal or excessive. " US4,378,694 (automotive)

there are also examples for motorcyle systems, fertilizer spreaders, and weaving systems. ...
imho, adapter is too simple & borders on malpractice for the translation ...