VIBRATION TRANSDUCER

• US 3,633,053 A
• Filed: 06/18/1970
• Issued: 01/04/1972
• Est. Priority Date: 06/18/1970
• Status: Expired due to Term

• Current Assignee: Rex B. Peters
• Original Assignee: Rex B. Peters
• Inventors: Peters, Rex B.
• Primary Examiner(s): Duggan, D. F.
• Application Number:
  US05/047,272
• Time in Patent Office: 565 Days
• Field of Search: 310/15,30,14 340/17 73/71.2 336/132,30
• US Class Current: 310/15
• CPC Class Codes: H02K 33/02 with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs
• CPC Class Codes: H02K 35/02 with moving magnets and stationary coil systems

Abstract

Vibration transducer having a sealed capsule secured concentrically to an integral soft iron pole piece. An elongate bar magnet is slidably mounted in the capsule and has substantially coincident magnetic and mechanical axes. Suitable means is mounted within the capsule and engages opposite ends of the bar magnet and serves to yieldably retain the bar magnet in a predetermined position within the capsule. The capsule is filled with gas. The capsule and bar magnet are formed in such a manner that there is provided a passage for the controlled flow of gas from one end of the magnet to the other end of the magnet as the magnet moves from its predetermined position. Electromagnetic coil means is provided for detecting the movement of the magnet within the capsule.

Claims

1. In a vibration transducer, a capsule assembly comprising a sealed capsule having an elongate bore therein, and a cylindrical soft iron pole piece secured to the capsule exterior of and substantially concentric with the capsule, said capsule including an elongate bar magnet formed solely of magnetic material slidably mounted in said capsule, yieldable means mounted within the capsule and engaging opposite ends of the bar magnet and serving to yieldably retain the bar magnet in a predetermined position within the capsule, a gas filling said capsule, said capsule and said magnet being formed to provide a gas passage therebetween to permit the controlled flow of gas from one end of the capsule to the other end of the capsule past the bar magnet, said gas passage extending only over a portion of the circumferences of the bar magnet, a case enclosing said capsule and electromagnetic coil means in said case for sensing movement of said bar magnet in said capsule.

2. A transducer as in claim 1 wherein said passage for the flow of gas is formed so that substantially linear damping of the magnet is obtained.

3. A transducer as in claim 1 wherein said electromagnetic coil means is in the form of a pair of windings with the windings wound in opposite directions so that their outputs are additive.

4. A transducer as in claim 3 wherein said electromagnetic coil means has a length which is greater than the length of the magnet and the extremes of travel of the magnet within the capsule.

5. A transducer as in claim 3 wherein said gas passage is formed by diametrically opposed recesses in said magnet.

6. A transducer as in claim 1 wherein said soft iron pole piece is secured to said capsule assembly.

7. A transducer as in claim 1 wherein said magnet and the capsule assembly containing the magnet are precisely centered with respect to each other so that side loading on the magnet is minimized.

8. In a vibration transducer, a case, a bore in said case, a sleeve of soft iron mounted in said bore and forming a pole piece, a tube carried by said sleeve and secured to said sleeve, said tube having a bore depending longitudinally thereof, a bar magnet formed solely of magnetic material slidably mounted in said bore, a pair of end plugs mounted in said tube and serving to seal said tube so that there is provided therein a hermetically sealed chamber, a gas filling said chamber, means engaging said end plugs and the ends of said magnet for yieldably retaining said magnet in a predetermined position in said bore, A cap carried by said case, said cap having a cylindrical extension having a bore therein receiving said tube and a coil wound on said cylindrical extension and encircling said tube, said tube and said magnet being formed so as to provide a gas passage therebetween from one end of the chamber to the other and extending over only a portion of the surface of the magnet to permit the flow of gas in a controlled manner from one end of the chamber to the other past the magnet.

9. A transducer as in claim 8 wherein said sleeve and said tube are precisely positioned with respect to each other so that the magnet is uniformly attracted to all parts of the same to thereby reduce the side loading on the magnet.

10. A transducer as in claim 8 wherein said coil has a length which is substantially greater than the magnet and the limits of travel of the magnet within the tube.

11. A transducer as in claim 10 wherein said coil is in the form of a pair of windings wound in opposite directions and which are connected to each other so that outputs from the same are additives.

12. A transducer as in claim 8 wherein the passages are formed by recesses formed on the magnet and extending longitudinally of the magnet.

13. A transducer as in claim 8 wherein said end plugs are provided with centered bosslike portions and wherein said magnet is also provided with centered bosslike portions on opposite ends of the same and wherein said means engaging the end plugs and the ends of the magnet comprises a pair of coil springs mounted on said bosslike portions of the end plugs and the bosslike portions of the magnets, said bosslike portions on said plugs and said magnets being adapted to engage each other and to serve as stops to prevent flattening of said coil springs.