US3833771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-acoustic transducers
Assignee: WHARFEDALE Ltd
•
Filing: 1973-05-29
•
Granted: 1974-09-03
•
Expires: 1993-05-29
Abstract
Abstract A transducer assembly for a flat diaphragm transducer of the type having a non-magnetic diaphragm with a conductor in the form of spaced parallel strips on one face with a cooperating magnet structure comprising a plurality of elongate alternate magnetic poles, which can be readily assembled by unskilled labour is disclosed. The transducer assembly comprises two polygonal frames having inwardly directed flanges and peripheral upstanding flanges. The inwardly directed flanges serve to define the spacing between the magnet structure and the diaphragm when two such frames are assembled with the diaphragm therebetween and the magnet structures located by the upstanding peripheral flanges of the frame members which flanges project away from one another. The two frame members are clamped along at least two sides in correspondence with the inwardly directed flanges, and the clamping means also holds the magnet structures and a perforated backing plate onto the frame members.
Inventors
- 👤 J Collinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:10
CPC Classifications
H; H04; H04R; H04R9/00; H04R9/02; H04R9/04; H04R9/046; H04R9/047; G; G01; G01L; G01L11/00; G01L11/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
241 words
In an audio transducer of the type comprising: a non-magnetic diaphragm with a conductor on at least one face thereof, the conductor being formed as a plurality of elongate, parallel, series connected strips, a magnet structure presenting a plurality of elongate magnetic poles aligned with the spaces between the parallel strips of said conductor, adjacent poles having opposite poLarity whereby the magnetic field produced thereby extends substantially parallel to the plane of the diaphragm and orthogonal to the direction of said strips of said conductor where it intersects said conductor, and a perforated metallic backing plate in contact with the face of said magnet structure remote from said diaphragm, the improvement wherein: there are two individual magnet structures one on each side of said diaphragm each having a respective perforated metal backing plate, a frame structure comprising two frame members in the form of respective closed polygons, said frame members having inwardly directed flanges defining the separation between said diaphragm and said two magnet structures, and further upstanding flanges defining an upstanding wall extending around the periphery of said frame members, said upstanding wall having a height at least as great as the combined thickness of the associated said magnet structure and backing plate, and means clamping said two frame members together along at least two of said inwardly directed flanges with said diaphragm therebetween, said clamping means also holding said magnet structures and said backing plates on said frame members.
Claim 2
Dependent Claim
241 words
In an audio transducer of the type comprising: a non-magnetic diaphragm with a conductor on at least one face thereof, the conductor being formed as a plurality of elongate, parallel, series connected strips, a magnet structure presenting a plurality of elongate magnetic poles aligned with the spaces between the parallel strips of said conductor, adjacent poles having opposite poLarity whereby the magnetic field produced thereby extends substantially parallel to the plane of the diaphragm and orthogonal to the direction of said strips of said conductor where it intersects said conductor, and a perforated metallic backing plate in contact with the face of said magnet structure remote from said diaphragm, the improvement wherein: there are two individual magnet structures one on each side of said diaphragm each having a respective perforated metal backing plate, a frame structure comprising two frame members in the form of respective closed polygons, said frame members having inwardly directed flanges defining the separation between said diaphragm and said two magnet structures, and further upstanding flanges defining an upstanding wall extending around the periphery of said frame members, said upstanding wall having a height at least as great as the combined thickness of the associated said magnet structure and backing plate, and means clamping said two frame members together along at least two of said inwardly directed flanges with said diaphragm therebetween, said clamping means also holding said magnet structures and said backing plates on said frame members.
Claim 3
Dependent Claim
18 words
The transducer of claim 1 wherein there are a plurality of different diaphragms interposed between said frame members.
Claim 4
Dependent Claim
32 words
The transducer of claim 1 wherein said magnet structures each incorporate a perforated sheet of plasto-magnetic material, that is a material consisting of magnetic particles embedded in a matrix of non-magnetic material.
Claim 5
Dependent Claim
33 words
The transducer of claim 1, wherein said magnet structures include a plurality of individual strips of plasto-magnetic material, that is a material consisting of magnetic particles embedded in a matrix upon magnetic material.
Claim 6
Dependent Claim
17 words
The transducer of claim 3 wherein said magnet structures are formed of stacked laminations of plasto-magnetic material.
Claim 7
Dependent Claim
17 words
The transducer of claim 4 wherein said magnet structures are formed of stacked laminations of plasto-magnetic material.
Claim 8
Dependent Claim
25 words
The transducer of claim 1 wherein said magnet structures and said backing sheets associated with each frame member are secured to one another by adhesive.
Claim 9
Dependent Claim
90 words
The transducer of claim 1 wherein said at least two inwardly directed flanges are formed with pins projecting therefrom in a direction away from said upstanding wall flanges, and holes interspersed between said pins whereby two said frame members can be interconnected by passing said pins through said associated holes in said at least two inwardly directed flanges, the ends of said pins being deformed to form rivet heads holding the two frame members and their associated magnet structures to one another with said diaphragm clamped between said frame members.
Claim 10
Dependent Claim
61 words
The transducer of claim 1 wherein the free edges of at least two opposite upstanding flanges of each said frame member are inwardly bent over the outer surface of said associated magnet structure to hold said magnet structure in place, and means fastening the edges of adjacent faces of two frame members together with said diaphragm held between said two members.
Claim 11
Dependent Claim
53 words
The transducer of claim 9 wherein said frame members are formed of a thermoplastics material with an outwardly projecting lip coplanar with said at least two inwardly directed flanges, said lips being heated and fused together without distorting the adjacent portions of said frame members which are thereby heat sealed to one another.
Claim 12
Dependent Claim
65 words
The transducer of claim 1, wherein at least one of said inwardly directed flanges of each said frame member is provided with gaps in corresponding positions to define, when said two frame members are located together, an opening to receive a plug for connecting the two ends of said conductor strip on said diaphragm to a source of electrical supply when said transducer is assembled.
Claim 13
Dependent Claim
33 words
The audio transducer of claim 1, wherein said frame members are constructed from a plurality of angle section frame elements joined at the eNds thereof to form the corners of said frame members.
References Cited (Backward Citations)
US3164686A
Cited
US3674946A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |