US3296586A

US3296586A - Transducer and housing assembly

Info

Publication number: US3296586A
Application number: US456629A
Authority: US
Inventors: Bernard J Midlock; Ralph L Piatt
Original assignee: Laboratory For Electronics Inc
Current assignee: Laboratory For Electronics Inc
Priority date: 1965-05-18
Filing date: 1965-05-18
Publication date: 1967-01-03
Anticipated expiration: 1984-01-03

Description

Jm; 3; 1967 B. J. MIDLOCK ETAL 3,296,586

TRANSDUCER AND HOUSING ASSEMBLY Filed May 18, 1965 2 Sheets-Sheet l FYGTTA INVENTORS BERNARD J. MIDLOCK RHLPH L. PIHTT BYQQQSGAQHQMLLO ATTORNEY Jamw3h 19676 B. J. MIDLOCK ETAL 3,296,536

TRANSDUCER AND HOUSING ASSEMBLY Filed May 18, 1965 2 Sheets-Sheet 2 is 39 I 52 INVENTORS BERNRRD J. MIDLOCK RHLPH L. PIHTT ATTORNEY The following invention relates to a housing and mounting assembly for an electro-acoustic transducer that directs a generated sonic beam toward a designated zone to be monitored and redirects the reflected response from vehicles within the zone toward the transducer.

By} means ofathe invention we have overcome deficiencies known in the prior art and have provided a new and improved. simplified one-piece, mounting diaphragm which receives a transducer, so that the diaphragm and transducer form a unitary assembly. Therefore, due to nlted States fiatent O F which is adapted for use with an. acoustic lens assembly 7 this] unitary construction, the transducer and diaphragm may be rapidly and positively mounted and removed from an operative position within a housing. It is.;an object ofthis invention to provide a new and improved housing and mounting assembly for a transducerused in vehicle detection.

,A further. object is to provide the housing and mounting assembly with sonic wave dampening means to elimihate or at least reduce strong internal reflections.

Other objects and advantages will become evident during the course oftheufollowing description which is to be taken in conjunction with the accompanying drawings illustrating the mounting assembly.

.Generally,.this invention is directed to an assembly comprisinga housing and a mounting diaphragm, having a central cylindrical portion which is extruded and lies perpendicular to a substantially flat planar surface of an annular. configuration and which surface and extrusion definesfithe diaphragm. The extruded portion of the mounting diaphragm receives a portion of a transducer withthe latter being releasably held within the extrusion, so..that,the diaphragm and transducer can be mounted j withinthe housing as one piece.

compasses theuse of a porous material within the housing 5 to substantially eliminate strong internal reflections.

The invention also en- In :the accompanying drawings which illustrate and l form a part: of this application, and in which like numeralsflareemployed to designate like parts" throughout the same,.;

1 1G511 is an exploded view in perspective of the mounting assembly which forms our invention;

FIG. i 2 lis an elevational view, partly cut away and partly in section of the parts of the assembly shown in FIG. 1 butin the assembled condition; and

w FIG.13 is a view taken along the line 3-3 in the directionuof the arrows as shown in FIG. 2 illustrating the mounting ring and associated structure.

Referring now to;the drawings and FIGS. 1 and 2 in particular, weshow for the purpose of illustration the several parts which make up our invention in both the assembled and unassembled condition.

Inwthese several figures, the complete housing and mounting assemblyiis denoted by the numeral 20 and this assembly is connected to a support structure 21, partially seen in FIG. 2, and which support is conveniently carried on a mount so as to locate the assembly adjacent a roadway. The, support carries a downwardly depending collar portion 22 which is integral with and located at one end thereof. The collar is of, a cylindrical configuration and ;within the collar the neck 23 of the housing assembly is telescopically received. The neck, as also seen in FIG. 2, has a groove 24 formed therein with the groove extending completely around the cylindrical surface of the neck.

Threadedly received through the collar so that their ends terminate within the groove cut in the neck 23 are one or more bolts 25. In FIG. 2 we show a pair of bolts, but, obviously, additional bolts may conveniently be used. By means of the bolts and groove, when in interacting relationship, the assembly 20, after being received and angularly adjusted on the collar of support 21, may be positively located in desired position with respect to the roadway. Although not shown in the figures, a decal or its equivalent is affixed on the housing to generally indicate the proper angular position of the housing in relation to the roadway and vehicle travel thereon.

The housing assembly, adapted to be mounted on the support 21, is made up of an upper housing portion 26 and a lower housing portion 26'. The upper housing is generally of a bell shaped configuration, that is, the top wall is substantially closed and the side walls generally extend from the top wall in both a downward and outward direction to define an opening at the bottom. The side walls terminate to form a fiat annular portion 27 located radially outward from the top with the annular portion being in a plane generally parallel to the plane of the top wall. Within this annular portion and at a plurality of angularly spaced locations at least a pair of holes 29 are drilled which are adapted to receive fastening screws for joining the housing portions together.

The lower housing is substantially of a cylindrical shape and is open at both ends. The cylindrical walls are shown to be thicker at the top than at the bottom of the lower housing and into the former portion, a plurality of angularly spaced threaded holes 30 are formed. These holes are to be in alignment with the holes in the annular ring of the upper housing 26, so that the two housing portions may be releasably secured together by screws 31.

From the peripheral edge of the annular portion 27 a depending, annular flange 28 is formed so that the flange, when the housing portions are assembled, lies in circumjacent relation to the lower housing 26'. As would be apparent, this flanged portion aids in the alignment of the housing portions prior to their assembly, and further functions, when the portions are assembled, to partially prevent dirt or other foreign objects from entering the assembly at such connection. 1

To maintain a tight connection between the

housing portions

26 and 26 shakeproof washers 32 may be mounted intermediate the head of screws 31 and the annular surface 27. Such is well known in the prior art.

Since the housing portions are formed of a low porosity substance, such as metal which is highly reflective and, therefore, displays reflective capabilities for sonic waves, it has been found that there is a need to provide a porous liner within the lower housing and suitably along the longitudinal extent and in circumjacent relation with the inner cylindrical wall. Such a liner will function to eliminate or at least substantially reduce internal sonic reflections within the lower housing occasioned by strong received pulses. Therefore,

liner rings

33 and 34, formed of sponge rubber, a high porosity plastic, or other high porosity substance, are received in the lower housing with the result that the strong received pulses directed toward the walls of the lower housing are absorbed" in the liner so as to be substantially dampened, and thereby eliminate any internal reflections. The liner ring 33 may be mounted on the internal wall of housing portion 26' in any suitable manner and the liner ring 34 is mounted, in a similar fashion, on a frame 35 which is frictionally received within the lower housing. Detents (not shown) may be used.

Also mounted on and supported by the frame 35 is a screen 36. The mesh of the screen should be of such size that any water or moisture which may gather within the housing will readily pass through the screen in the form of droplets having little surface adhesion with the mesh. Further, the mesh should be of such size to prevent bugs or other foreign matter from entering the lower housing. A 30-mesh wire cloth of 0.010 inch wire is suitable, for example.

Adapted to be supported within the housing assembly, at the point where the upper and lower housing portions are connected, is a mounting diaphragm 37. The mounting diaphragm, which can be seen in all figures, comprises :an extruded cylindrical portion 38 and a substantially flat annular portion 39, which is transverse to the extruded part.

At angularly spaced points in the annular portion of the diaphragm and near its outer periphery, a plurality of holes 52 are formed. All of these holes are to be in registry with the

holes

29 and 30 formed in the upper and lower housings, respectively. Therefore, when the housing portions are assembled together, the mounting diaphragm, which removably carries the transducer 40, to be discussed 'below, is received between the housing portions and fixedly secured in suCh position by the screws 31.

The mounting diaphragm 37 preferably is made of a strong plastic material of high stability over wide temperature range, and of low sound or vibration transmission characteristics, such as an ABS polymer (acrylonitrile-butadiene-styrene) which is marketed under the trade name of Boltaron, for example. This material is available from the Plastics Division of General Tire and Rubber Company. In one preferred embodiment, this diaphragm may be approximately 7 inches in outside diameter with the extruded cylindrical portion being approximately 3% inches in inside diameter, with a thickness on the order of W inch. The diaphragm, preferably of Boltaron 6000 series material, may have the following specifications: a modulus of elasticity of about 260,000 pounds per square inch (although this may vary in different samples), a tensile strength of about 3600 pounds per square inch at 72 F. and izod impact strength, in ft. lbs. per inch of notch, of 8 to 10 at +70 F. and 3 to 4 at 40 F. Therefore, the diaphragm 37 is a ring of material having a stiffness equivalent to the aforementioned values, with a vibration absorbing quality for ultrasonic frequencies near or above 19 kilocycles, for example.

The 6000 series Boltaron material exhibits good sound and vibration dampening characteristics, particularly for ultrasonic waves, and maintains its shape and a sufiicient impact strength over a wide temperature range (-40 F. to +160 F.). The latter is of prime concern since this mounting diaphragm will be subjected to varying climatic conditions.

Another material suitable for the mounting diaphragm is a substance known as Teflon T.F.E. (tetrafluoroethylene) supplied by E. I. du Pont de Nemours & Co. Although Teflon T.F.E. has even higher temperature stability in impact strength, and excellent sound and vibration dampening characteristics, it cannot be extruded like the Boltaron material, but must be molded, and basically is considerably more expensive at present.

Drainage holes 62 are preferably provided through diaphragm 37 to permit any condensation to drain ofi'.

Supported within the housing 20, as shown in FIG. 2, and on the mounting diaphragm 37, is a transducer generally indicated by the numeral 40. The transducer is formed with a substantially cylindrical portion 41 at one end and which cylindrical portion depends from a flanged area 42.

The cylindrical portion 41 is part of an annular ring having an inner flared surface 50. A central projecting member or phasing plug 61 of modified conical form has an outer flared surface 51.

Above the flared area 42 is the main or operative part of the transducer and suffice it to say, this comprises a permanent magnet 43, a pair of ring shaped pole pieces 44 and 45 which are spaced from one another to define an area occupied by a coil 46, and a relatively thin, annular, metallic diaphragm 47. By means of the permanent magnet, the pieces, coil and diaphragm, electrical energy received at the terminals 48 is transformed into sonic energy to be directed from the diaphragm 47 and through the horn portion 49 defined by the

surfaces

50 and 51 of the transducer. Since the particular construction and specific operation of the transducer does not form a part of this application, the foregoing discussion is considered as being adequate for our purposes.

In the mounted position, the cylindrical portion 41 of the transducer is slidably received within the extrusion 38 of the diaphragm 37. As seen in FIG. 2 the flanged portion 42 will then rest upon the annular surface 39 so as to be supported by the diaphragm.

Once the cylindrical surface 41 of the transducer is received within the extruded portion so that the flanged surface 42 rests upon the annular portion 39 of the mounting diaphragm, a fastening clamp 53 is received over the extruded portion and tightened in such position by the nut and bolt, '54 and 55, respectively, received in the clamp. As seen in FIGS. 1 and 3, the clamp is formed in a circular configuration with the opposed ends being flanged outwardly. The bolt is received in a hole formed in the flanged ends of the clamp, the nut is attached thereto and tightened so as to draw the clamp together and slightly compress the extruded portion 38. Therefore, the extruded portion will frictionally bind on the cylindrical portion 41 of the transducer to retain the transducer in the assembled position.

Received on the cylindrical surface 41 of the transducer 40, so as to be disposed at the horn 49 is a mounting bracket 56. The bracket can be seen in FIG. 2 and is formed in a rectangular configuration having a central cylindrical opening 57 and an annular cut out portion 58. The annular cut out defines a flanged area 59, and this flanged area determines the extent to which the mounting bracket may be received on the cylindrical surface 41. The bracket, which carries an acoustic lens (not shown), is, further, releasably attached to the cylindrical surface of the transducer in any convenient manner.

From the foregoing, it is evident that we provide a new and improved mounting construction for a transducer and provide a complete unit which may easily be assembled and disassembled into a minimum of parts.

The transducer is received in, supported by and secured to the mounting diaphragm and this unit is positioned intermediate the housing portions when connected together. Therefore, the transducer is positively supported by means of a single diaphragm without the need of additional resilient members so as to force the transducer toward a seat formed in the housing.

Although the invention has been disclosed and shown by what is considered to be the preferred embodiment; the invention is not to be construed as limited to this embodiment, but rather the invention encompasses the generic area as hereinbefore disclosed. Various modifications and embodiments of this invention can be made without departing from the spirit and scope thereof.

We claim:

1. In an ultrasonic detector adapted to be mounted on a support adjacent a roadway for the detection of vehicles within a defined zone,

an electro-acoustic transducer of the type which utilizes a horn loaded diaphragm for transmission or recep tion of a generally divergent beam of ultrasonic waves,

said transducer having a substantially cylindrical end portion and an outwardly directed flanged portion,

.a housing having an opening and a portion spaced therefrom adapted to be connected to said support to locate said housing in relation to said roadway so i that saidrbeam is directed throughsaid opening in said housing andtoward said defined zone,

andqmounting means for supporting said transducer withinsaid housing, said means comprising a relatively thin resilient but substantially rigid disc of plastic material of sound and vibration dampening characteristic, said disc having a substantially central opening and an inner flange formed integrally with said disc and disposed coaxially with respect to said opening,

means for releasably connecting the periphery of said disc, to a substantially central portion of said houssaid cylindrical portion of said transducer being telescopically received within the flanged portion of said disc so that the flanged portion of said transducer is supported on said disc,

andmeanscomprising a fastening clamp that is received in surrounding relation to the flanged portion ofqsaidi disc to bind the transducer thereto for releasably mounting said transducer on said disc. 2., A combination as in claim 1 and in which said housing includes upper and lower separable parts between which said disc is clamped ,when coupled together,

and fastening means for detachably coupling together M said upper and lower parts.

3.1A combination as in claim 2, and in which said upper :part of said housing is generally bell-shaped with a laterally ,grooved upper neck portion for adjustable coupling to fastening members in said support.

4. [A combination as in claim 1, and in which said housing includes upper and lower separable parts between whichsaid disc is clamped when coupled together, and fastening means for detachably coupling together saidupper: and lower parts, said lower part of said housing being of substantially cylindrical shape providing said opening at its lower end, a screen, a substantially cylindrical frame attached to said screen for insertion into said opening in said housing for attachment thereto, and said combination also including generally cylindrical liners of: sponge-like cellular material, with a open cellular surpface, :covering a substantial part of the inner cylindrical wallsiof saidlower; part of said housing and of said frame ofrsaid screen for absorbing vibrations and ultra sonicjwaves.

5., A combination as in claim 1 and including a liner of, ultra-sonic, wave absorption sponge-like cellular material, such as sponge rubber, with an open cellular surface, said liner being received within and over a substantial portion of the walls of said housing to substantially reduce internal reflections of ultra-sonic waves.

6. In an ultrasonic detector adapted to be mounted on a support adjacent a roadway for the detection of vehicles within a defined zone,

an electro-acoustic transducer of the type which utilizes a horn loaded diaphragm for transmission or reception of ,a generally divergent beam of ultrasonic waves,

said, transducer having a substantially cylindrical end portion and an outwardly directed flanged portion,

a housing having an opening and a portion spaced therefrom adapted to be connected to said support to locate said housing in, relation to said roadway so thatsaid beam is directed through said opening in said housing andtoward said defined zone,

andgmounting means for supporting said transducer within said housing, said means comprising arrelatively thin resilient but substantially rigid disc of highly stable plastic material, such as acrylonitrile butadiene styrene of high impact strength, of sound and vibration dampening characteristic, said disc having a substantially central opening and an inner flange formed integrally with said disc and disposed coaxially with respect to said opening,

means for releasably connecting the periphery of said disc to a substantially central portion of said houssaid cylindrical portion of said transducer being telescopically received within the flanged portion of said disc so that the flanged portion of said transducer is supported on said disc,

and means for releasably mounting said transducer on 7 said disc.

7. A combination as in claim 6 and in which said housing includes upper and lower separable parts between which said disc is clamped when coupled together,

and fastening means for detachably coupling together said upper and lower parts.

8. A combination as in claim 7, and in which said upper .part of said housing is generally bell-shaped with a laterally grooved upper neck portion for adjustable coupling to fastening members in said support.

9. A combination as in claim 6, and in which said housing includes upper and lower separable parts between which said disc is clamped when coupled together, and fastening means for detachably coupling together said upper and lower parts, said lower part of said housing being of substantially cylindrical shape providing said opening at its lower end, a screen, a substantially cylindrical frame attached to said screen for insertion into said opening in said housing for attachment thereto, and said combination also including generally cylindrical liners of sponge-like cellular material, with an open cellular surface, covering a substantial part of the inner cylindrical walls of said lower part of said housing and of said frame of said screen for absorbing vibrations and ultrasonic waves.

10. A combination as in claim 6 and including a liner of ultra-sonic wave absorption sponge-like cellular mate rial, such as sponge rubber, with an open cellular surface, said liner being received within and over a substantial portion of the walls of said housing to substantially reduce internal reflections of ultra-sonic waves.

11. In an ultrasonic detector adapted to be mounted on a support adjacent a roadway for the detection of vehicles within a defined zone,

an electro-acoustic transducer of the type which utilizes a horn loaded diaphragm for transmission or reception of a generally divergent beam of ultrasonic waves,

a housing having an opening and a portion spaced therefrom adapted to be connected to said support to locate said housing in relation to said roadway so that said beam is directed through said opening in said housing and toward said defined zone,

and mounting means for supporting said transducer within said housing, said means comprising a relatively thin resilient but substantially rigid disc of plastic material of sound and vibration dampening characteristic, said material being composed of a highly stable fluorocarbon polymer such as tetrafluoro ethylene, said disc having a substantially central opening and an inner flange formed integrally with said disc and disposed coaxially with respect to said opening,

means for releasably connecting the periphery of said disc to a substantially central portion of said housing, said cylindrical portion of said transducer being telescopically received within the flanged portion of said disc so that the flanged portion of said transducer is supported on said disc,

and means for releasably mounting said transducer on said disc.

12. A combination as in claim 11 and in which said housing includes upper and lower separable parts between which said disc is clamped when coupled together,

13. A combination as in claim 12, and in which said upper part of said housing is generally bell-shaped with a laterally grooved upper neck portion for adjustable coupling to fastening members in said support.

14. A combination as in claim 11, and in which said housing includes upper and lower separable parts between which said disc is clamped when coupled together, and fastening means for detachably coupling together said upper and lower parts, said lower part of said housing being of substantially cylindrical shape providing said opening at its lower end, a screen, a substantially cylindrical frame attached to said screen for insertion into said opening in said housing for attachment thereto, and said combination also including generally cylindrical liners of sponge-like cellular material, with an open cellular surface, covering a substantial part of the inner cylindrical walls of said lower part of said housing and of said frame of said screen for absorbing vibrations and ultrasonic waves.

15. A combination as in claim 11 and including a liner of ultra-sonic wave absorption sponge-like cellular material, such as sponge rubber, with an open cellular surface, said liner being received within and over a substantial portion of the walls of said housing to substantially reduce internal reflections of ultra-sonic waves.

16. In an ultrasonic detector adapted to be mounted on a support adjacent a roadway for the detection of vehicles Within a defined zone,

an electro-acoustic transducer of the type which utilizes a horn loaded diaphragm for transmission or receptionof a generally divergent beam of ultrasonic waves,

and mounting means for supporting said transducer within said housing, said means comprising a relatively thin resilient but substantially rigid disc of plastic material of sound and vibration dampening characteristic, said disc having a substantially central opening and an inner flange formed integrally with said disc and disposed coaxially with respect to said opening, said disc being provided with holes therethrough for drainage purposes,

means for releasably connecting the periphery of said disc to a substantially central portion of said housing,

said cylindrical portion of said transducer being telescopically received within the flanged portion of said disc so that the flanged portion of said transducer is supported on said disc,

and means for releasably mounting said transducer on said disc.

References Cited by the Examiner UNITED STATES PATENTS 2,477,507 7/ 1949 Africano 34017 2,582,769 1/1952 Congdon 340-17 2,947,823 8/1960 Harris 340-17 X 3,030,606 4/1962 Harris 34017 X 3,109,155 10/1963 Degen 34015 BENJAMIN A. BORCHELT, Primary Examiner. P. A. SHANLEY, Assistant Examiner.

Claims

1. IN AN ULTRASONIC DETECTOR ADAPTED TO BE MOUNTED ON A SUPPORT ADJACENT A ROADWAY FOR THE DETECTION OF VEHICLES WITHIN A DEFINED ZONE, AN ELECTRO-ACOUSTIC TRANSDUCER OF THE TYPE WHICH UTILIZES A HORN LOADED DIAPHRAGM FOR TRANSMISSION OR RECEPTION OF A GENERALLY DIVERGENT BEAM OF ULTRASONIC WAVES, SAID TRANSDUCER HAVING A SUBSTANTIALLY CYLINDRICAL END PORTION AND AN OUTWARDLY DIRECTED FLANGED PORTION, A HOUSING HAVING AN OPENING AND A PORTION SPACED THEREFROM ADAPTED TO BE CONNECTED TO SAID SUPPORT TO LOCATE SAID HOUSING IN RELATION TO SAID ROADWAY SO THAT SAID BEAM IS DIRECTED THROUGH SAID OPENING IN SAID HOUSING AND TOWARD SAID DEFINED ZONE, AND MOUNTING MEANS FOR SUPPORTING SAID TRANSDUCER WITHIN SAID HOUSING, SAID MEANS COMPRISING A RELATIVELY THIN RESILIENT BUT SUBSTANTIALLY RIGID DISC OF PLASTIC MATERIAL OF SOUND AND VIBRATION DAMPENING CHARACTERISTIC, SAID DISC HAVING A SUBSTANTIALLY CENTRAL OPENING AND AN INNER FLANGE FORMED INTEGRALLY WITH SAID DISC AND DISPOSED COAXIALLY WITH RESPECT TO SAID OPENING, MEANS FOR RELEASABLY CONNECTING THE PERIPHERY OF SAID DISC TO A SUBSTANTIALLY CENTRAL PORTION OF SAID HOUSING, SAID CYLINDRICAL PORTION OF SAID TRANSDUCER BEING TELESCOPICALLY RECEIVED WITHIN THE FLANGED PORTION OF SAID DISC SO THAT THE FLANGED PORTION OF SAID TRANSDUCER IS SUPPORTED ON SAID DISC, AND MEANS COMPRISING A FASTENING CLAMP THAT IS RECEIVED IN SURROUNDING RELATION TO THE FLANGED PORTION OF SAID DISC TO BIND THE TRANSDUCER THERETO FOR RELEASABLY MOUNTING SAID TRANSDUCER ON SAID DISC.