US2141641A - Sound signal - Google Patents

Description

Dec. 27, 1938. R. M. CRITCHFIELD A SOUND S IGNAL I Filed July 27, 1929 Patented Dec. 27, 1938 UNITED STATES PATENT OFFiCE SOUND SIGNAL ware Application July 27, 1929, Serial No. 381,515

13 Claims.

This invention relates to improvements in sound signalling devices particularly adaptable for use on motor vehicles.

It is among the objects of the present invention to provide a sound signalling device, or

warning instrument, of simple structure and design which may be produced at a minimum expenditure of time and labor.

Another object of this invention is to provide a horn or a signalling device which may be adjusted or regulated to vary the quality and intensity of sound produced, without disturbing the adjustment or affecting the operativeness of the driving motor or any other portion of the mechanism.

Another object of the invention is to provide a Warning signal that will be substantially free of mechanical noise and that will approximate the tone of an air horn. z

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 is an elevation of my sound signal device, with parts thereof broken away to show the operative mechanism thereof in longitudinal section, substantially as would appear along the line and in the direction of the arrows of Fi 2.

Fig. 2 is an end view looking in the direction of arrow 2 of Fig. 1 with the motor housing in cross section.

Fig. 3 is a sectional view on line 3-3 of Fig. 2.

Fig. 4 is a view of a piston disc illustrating a detail of its construction.

With particular reference to the drawing the numeral 28 designates a base, cup-shaped in form,

upon which is supported the operating mechanism of the horn.. The bottom of the base 28 is termed the main mounting platform 2|. The central portion of this platform 2| is apertured,

the metal punched out of the bottom to form the aperture being bent up to provide a bracket 22 having a portion 23 substantially parallel with but spaced from the mounting platform 2 I. An-

other bracket 24 formed from the material punched out of the bottom to form the aperture, provides a bracket diametrically opposite the bracket 22. The base 28 is provided with an outwardly extending flange 25 having a plurality of apertures for receiving screws 26 which pass through apertures in a flange 21 of a collar 28 to secure said collar to the base 28. A diaphragm 29 is interposed between the flanges 25 and 21 and is clamped tightly therebetween by means of the screws 26 thus providing a yieldable partition between the collar 28 and the base 20. 5

Upon the parallel portion 23 of the bracket 22 there is secured at one end a blade spring 30, which extends toward the center of the base and parallel with the main mounting platform 2|, and the circuit controller mechanism of the motor unit is insulatingly mounted upon this bracket in substantial parallel relation with said blade spring as will presently appear. In the present instance the circuit controller mechanism comprises a leaf spring bracket 3| which provides a nonconducting buffer block 33 and a movable contact 32 which cooperates with an adjustable contact 35 carried by a rigid bracket 34 in substantial alignment with the contact 32. These contact supporting elements are secured to the bracket 23 by screws 36.

To the free end of the blade spring 38 there is secured an angular bracket or stirrup 38 which has an adjustable screw 39 supported in its free end, and adapted to engage the insulating member or buffer 33 carried on the movable contact arm 3|. Upon movement of the stirrup 38, the blade spring 38 functions to open the circuit between the contacts 32 and 35. A rod 40 is secured to the free end of the blade spring 38 and extends through the diaphragm 29 and spacing washers 4| and 42. Washers 4| and 42 and diaphragm 29 are clamped against a shoulder 48a of the rod 40 by a nut 43 threadedly engaging the rod. The armature rod 40 thus terminates within the sound chamber defined by the collar 28, substantially coaxial with the orifice thereof. On this threaded extension 44 of the armature rod there is mounted a piston disc 45 which is secured in place by a nut 46.

The collar 28 is formed to provide a chamber 58 that embodies the annular plane portion 5| merging into the conical aperture 52, that leads into the relatively small neck 53 within which is secured the mouth 54 of a trumpet 55. Collar 28 may be formed in any preferred manner, but it is desirable that the portion 5| be finished to a plane surface, though the adjacent surfaces of the piston 45 and portion 5| may be conical and substantially parallel. Thus, the chamber 50 is defined by the collar member 28 in the appointments just described and the yieldable partition member or diaphragm 29. In assembled form the armature rod 48 lies substantially coaxial with th s chamber and supports the piston 45 in close 55 c of the insert 56.

proximity to the plane portion 5| of the collar 28. In the instant invention it is desired that a relatively close approach between the disc 45 and the plane 5| may be obtained, and this is accomplished by providing the disc 45 with an insert 56 centrally thereof and that has threaded engagement with the threaded portion 44 of the armature rod 40. The insert 56 is provided with a flange 5'! on one side of the disc, which flange is notched at equally spaced points as 58 for cooperation with a special tool or instrument to'aid in turning the insert and consequently the disc 45 upon the threaded portion of the rod 40. When the disc assembly, as illustrated in Fig. 4, has been threaded upon the armature rod 46 and adjusted to the proper position, it is secured thereto by the lock nut 46. positioned and proportioned in dimension, that adjustment of the disc 45 relative to the rod 46 may be made either before the mechanism has been assembled, or after assembly has been completed. V

The adjustment is accomplished when the apparatus has been assembled, by inserting a tubular form of the spanner wrench within the trumpet 55 to engage the notches 58 in the flange While holding the wrench in engagement therewith, a socket wrench is then inserted within the tubular spanner wrench to engage the nut 46, by which it is loosened sufiiciently to allow the desired adjustment of the disc 45 upon the armature rod 40. When the desired adjustment of the disc 45 relatively to i the plane 5| has been obtained, the tubular rod and plane, while the socket wrench is reinserted to tighten the nut 46 and secure the, disc 45 in the altered position upon the rod 46. Thus,

adjustment of the air gap 60 betweenthe disc 45 and plane portion 5| may be altered after the sound signal has been mounted upon the vehicle,

and without disturbing any of the other parts of the device.

An armature 65 is carried on the rod 40 adjacent the free end of the spring 36, said armature being maintained in normal position by the tension in the spring 30 and the diaphragm 29. The armature 65 is reciprocated or actuated by means of an electro-magnet device comprising a field frame 66 which is adjustably supported on the mounting platform 2| of the base. The field frame comprises a plurality of E-shaped magnetic plates 67 riveted together, the E-shaped plates forming parallel grooves 68 and 69 into which a field winding 10 is adapted to be placed. The end plates H and 12 of the field frame are provided with angular shelf portions 13 and 14 respectively, said portions being apertured at Hand 76 to permit insertion of the field wlnding 'fll into the grooves 68 and 69. V The shelf 14 is provided with a central aperture 11 while the shelf 13 has two such apertures spaced on opposite sides of the center. These apertures 11 are so designed and spaced as to cooperate with threaded studs 18 secured in the mounting platform 2| as illustrated in 'Fig. 2

and each of the threaded studs is provided with a pair of nuts 19 and 86, one being disposed each side of the shelf portions 13 and .74. The nuts 19 and 88 upon the stud 18 provide a means of adjusting and securing the field frame 66 in proper relation with respect to the mounting platform 2|, it being obvious that the nut 19 may be run up and down on the stud 18 to determine the These partslare so' armature 7 device.

supports the armature 65 in close proximity to the field frame 66 and that the rod 40 is reciprocably movable through the aperture 85 of the field frame. When it is deemed that the gap between the armature and field frame is too great, then the nuts 80 of the studs 18 may be loosed and the spacing nuts 19 thereof run out to properly position the field frame 80 again run down as before.

In the operation of this sound signal, energization of the field frame or electro-magnetic unit attracts the armature 65 against the efiect of and the nuts the spring 36 and the diaphragm 29. The arm'a ture is thereby moved toward the field frame and consequently flexes the diaphragm outwardly toward the trumpet 55 and carries with it the disc 45. This movement of the armature will cause the contact carrying member 3| to be flexed to open the circuit through the contact points 32 r and 35, and permit the spring 36 and diaphragm 29 to return to normal position again closing the contacts 32 and 35 which reconditions the parts for the above cycle of movement. The disc 45 acts principally in the capacity of a piston in cooperation with the plane 5| of the collar 28. As earlier stated the disc 45 is adjusted so that it is in preference in close proximity t the plane 5| at the extreme of the electrically energized movement'of the rod and armature. That is, it is so adjusted with respect to the plane 5| and rod '40 that when the rod 40 is at the left hand movement at which the armature is again ener gized, the'disc is stopped in'its return movement and again drawn toward the mouth of the trumpet. The effect produced is a delicate pulsation of sound as the piston sets the air column into vibration and when impressed upon-the other vibrations of the horn produces a penetrating warning signal of pleasing quality.

The area of the gap is such that when the disc 45 is in this extreme of approach or near that extreme that the rush of air or fiuid content from between the elements 45 and 5| will attain extremely high velocities. The fluid movement will suddenly cease or be terminated by complete cutting off or substantial cutting oif thereof due to the close approach of the elements described. By reason of this effect there is 'a rush of air through the aperture of the chamber 5| at the stated extreme ofeach vibratory stroke of the The sudden stopping of the fluid current'flowing through the neck into the trumpet sets the air column into rapid vibration and when contributed to by the sound produced by the diaphragm produces a sounding signal of very desirable qualities. The tone produced is remarkably free of mechanical noise and approximates the tone of an air horn so closely as to be barely detectable therefrom.

While I have illustrated the trumpet 55 as of drawn or spun formation, I do not limit myself to thatparticular form, but may formthe trumpet from a pair of symmetrical stampings which I may secure together by seaming or by welding, or I may cast the trumpet either integral with or separate from the collar 28.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming Within the scope of the claims which follow.

What is claimed is as follows:

1. A signal device comprising in combination; a base; a collar provided with a wall, said wall provided with an aperture having a conical portion and a neck portion; a trumpet secured in said neck portion; a diaphragm clamped between said collar and base; a disc extending over said conical portion and connected with said diaphragm, said disc lying in close juxtaposition to the mouth of said conical portion merging with said wall substantially at right angles to the axis of said collar; a motor carried by said base; a rod connecting said motor with the diaphragm and disc, said rod having an end extending into said conical portion; and means for altering the position of said disc relative to said wall, said means being located upon the end of said rod within the conical portion so that the unobstructed cross-sectional area of the passage through the conical portion and about the means is at least as great as the cross-sectional area of the smallest part of the outlet.

2. A signalling device comprising in combination; means providing a sound chamber having a fiat Wall with an outlet, said outlet having an enlarged portion and a smaller portion; a flat vibratory body located for movement in close proximity to said wall, means to adjust the vibratory body relative to said wall, said means located in the enlarged portion of said outlet so that the unobstructed cross-sectional area of passage between the means and the wall of the enlarged portion is at least as great as the crosssectional area of the smallest part of the outlet.

3. A sound signal comprising in combination; a magnet motor, a supporting plate for the same; a clamping collar provided with a Wall secured to said plate; said Wall having an outlet with an enlarged portion and a smaller portion, a vibrating diaphragm clamped between the plate and the collar to form an air chamber; a projector supported by said collar in Said smaller portion and providing the sole inlet and outlet to said chamber; a disc extending over said enlarged portion and in close proximity thereto, a rod connecting said motor with said diaphragm and disc, said rod extending into said enlarged open portion so that the unobstructed cross-sectional area of said enlarged portion around said rod is at least as great as the cross-sectional area of the smallest part of the outlet; means for varying the relative position of said disc with respect to said opening; and said motor actuating said diaphragm and disc to move air back and forth through said opening.

4. A horn including a housing, a vibratory diaphragm mounted in said housing, a motor mechanism connected to said diaphragm to flex the same, said housing being formed with a single orifice therein, comprising both an inlet and outlet for air and positioned beyond said diaphragm and a valve mechanism controlling the flow of fluid through said outlet opening.

5. A horn including a housing, a vibratory diaphragm mounted in said housing, a motor mechanism connected to said diaphragm to flex the same at' acoustical frequencies, said housing being formed with a single orifice therein, comprising both an inlet and outlet for air and positioned beyond said diaphragm and a valve mechanism controlling the flow of fluid through said outlet opening.

6. A horn including a housing, a vibratory diaphragm mounted in said housing, a motor mechanism connected to said diaphragm to flex the same at acoustical frequencies, said housing being formed with a single orifice therein, comprising both an inlet and outlet for air and positioned beyond said diaphragm, means providing a valve seat, a valve member cooperating with said seat, one of said elements being associated with said orifice and the second of the same being connected to said diaphragm.

'7. A horn including a housing, a vibratory diaphragm mounted in said housing, a motor mechanism connected to said diaphragm to flex the same at acoustical frequencies, said housing being formed with a single orifice therein, comprising both an inlet and outlet for air and positioned beyond said diaphragm, means providing a valve seat adjacent said orifice and a valve connected to said diaphragm and cooperating with said seat.

8. A horn including a housing formed with a single opening, comprising both an inlet and outlet for air, a disk providing a valve body to cooperate with said opening, a diaphragm mounting said disk and a motor for flexing said diaphragm at acoustical frequencies.

9. A horn including a housing, a vibratory diaphragm mounted in said housing, a motor mechanism connected to said diaphragm to flex the same at acoustical frequencies, said housing being formed with a single orifice therein, comprising both an inlet and outlet for air and positioned beyond said diaphragm, means providing a valve seat adjacent said orifice and a valve connected to said diaphragm and cooperating with said seat, said valve and seat being normally spaced a distance less than the normal tendency of movement on the part of said diaphragm.

10. A horn including a housing formed with a single opening, comprising both an inlet and outlet for .air, a disk providing a valve body to cooperate with said opening, means for vibrating said disk at acoustical frequencies and into engagement with the surfaces adjacent said opening and means for shifting said housing with reference to said body to vary the position of the opening relatively thereto.

11. A sound signal comprising in combination, a motor, a trumpet, a collar and'support therefor connected to the motor support for supporting the trumpet and having a peripheral diaphragm engaging portion, a diaphragm clamped between the edge of the collar and said motor and support and movable by the motor, said collar having a second portion joined to the diaphragm engaging portion and spaced from the surface of the diaphragm to form a chamber, an actuatable disc supported from the diaphragm in said chamber, so that the major portion of the area of the face of the disc opposite the diaphragm is in parallel relation with the said second portion of the collar, and means including the motor for thrusting the disc in such close proximity to the collar that the disc will be substantially in contact with the collar, so that the air column in the trumpet is practically stopped.

13. A sound signal comprising, in combination, a motor, a trumpet, a plate having an opening communicatingwith the trumpet and an annular substantially flat surface surrounding the opening, means cooperating with the said plate to form a sound chamber, a vibratory body operable by the motor within said sound chamber, and having a surface partially overlapping the flat surface of the plate and substantially parallel' thereto, and means normally supporting the vibratory body in such close proximity to the said flat surface that upon the extreme limit of its movement in one direction by said motor it substantially contacts with the surface to cut ofi the air columnof the trumpet from the sound chamber. 7

ROBERT M. CRI'I'CI-IFIELD.

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