4,072,871

43.88. Fx ELECTROACOUSTIC TRANSDUCER

Charles R. Wilson, assignor to Westinghouse Electric Corporation

7 February 1978 (Class 310/333); filed 20 May 1974

This patent describes an underwater transducer utilizing piezoelectric elements operating in a shear mode. Head and tail

masses are designed to lower the resonance frequency to a pre- ferred value. In the figure 10 and 11 are the head and tail masses, and 14 and 15 are the PZT cylinders. Several variations are described.-RWC

3,995,124

43.88. Kb NOISE CANCELLING MICROPHONE

Saad Zaghloul Mohamed Gabr, Canterbury, England 30 November 1976 (Class 179/139); filed 15 October 1974

This patent describes a microphone having dual opposed dia- phragms for the purpose of neutralizing noise pickup.-RWC

3,960,790

43.88. Ne DISC RECORD AND METHOD OF

COMPOUNDING DISC RECORD COMPOSITION

Satwan Kumar Khanna, assignor to RCA Corporation I June 1976 (Class 260/23 XA); filed 25 March 1974

A formula is disclosed for a plastic record molding composi- tion that is claimed to result in a record surface hard and smooth

enough for the 45-kHz bandwidth of discrete or modulation-type four-channel records. Such high frequencies challenge the surface material both as to the definition of the minute vibratory pat- terns to bc impressed, and as to the wear to which these micro- scopic mechanovibratory undulations can bc subjected before un- acceptable degrading occurs. This sort of information is often re- tained as a trade secret or disclosed with deliberate omissions in

the specifications. The present application appears forthright. One would suppose that a harder and smoother record is simply a better record in general, unless it is more brittle and more readily subject to breakage. Most persons dealing with records would do well to round out their knowledge by reading this patent.-DSG '

3,961,797

43.88.Ne PHONOGRAPH PICKUP CARTRIDGE STYLUS ROD

Tsunehiro Tsukagoshi, assignor to Pioneer Electronic Corporation

8 June 1976 (Class 274/37); filed 14 May 1974

Making the phonograph cartridge stylus rod (stylus arm) of beryllium-coated aluminum allows it to be made narrower and thinner-walled than if it were made of aluminum or titanium

alone. The light but strong stylus rod that results presents a re- duced equivalent dynamic mass as a key dynamic mass-contribut- ing element of the vibrating element assembly. Porosity of the outer beryllium layer is obtained by its vacuum vapor deposition onto the tapered aluminum rod, so the mass contributed by this outer layer is thus further reduced for higher tracking compli- ance.-DSG

4,000,370

43.88. Kb LINE LEVEL MICROPHONE WITH BUILT

IN LIMITER

Alan Douglas Smith and David Alan Yoshinari, assignors to Shure Brothers Incorporated

28 December 1976 (Class 179/1 A); filed 16 May 1975

The microphone aggregation described in this patent includes a capacitive (low-level) transducer, an amplifier and a limiting system utilizing a light-emitting diode.-RWC

4,081,628

43.88. Kb MICROPHONE, PARTICULARLY FOR BODY SOUNDS, WITH SLIP COUPLING TO THE TRANSDUCER ELEMENT

Rolf Neusel, Darmstadt, Germany 28 March 1978 (Class 179/121 R); filed 1 December 1976

As indicated by the title, the active element of a microphone is protected from damage by pressure against a body (or any ob- ject) by a slip coupling.-RWC

3,964,751

43.88.Ne PHONOGRAPH CARTRIDGE

REPLACEABLE STYLUS ASSEMBLY

Paul Vitale, assignor to Pickering & Company 22 June 1976 (Class 274/37); filed 31 July 1975

Crimping about the elastomeric grommet in a phono pickup restricts its free response and thus prohibits its ideal function as a universal joint. With the alternative fastening means for this

34t 32 30, 22 70

_ _ •

24

element the patent describes, "... the low mechanical impedance of grommet 30 is attained by having the damper engage tube 20 only along a single peripheral edge. The remainder of the damper is free of the tube and thus permitted to move."-DSG

293 J. Acoust. Soc. Am. 65(1), Jan. 1979; 0001-4966/79/010293-01500.80; ̧ 1979 Acoust. Soc. Am.; Patent Reviews 293

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