US2724111A - Vibratory horn motor comprising an electrical solenoid and interrupter - Google Patents

Description

Nov. 15, 1955 s w T 2,724,111

VIBRATORY HORN MOTOR COMPRISING AN ELECTRICAL SOL NOID AND INTERRUPTER Filed Nov. 19, 1954 I] E INVENTOR.

United States PatetitQ Application November 19, 1954, Serial No. 469,929

3 Claims. (Cl. 340-403) This invention is concerned with an electrical apparatus and is more particularly directed to a vibratory or oscillatory electric motor employed to activate the warning signal or horn commonly employed on motor vehicles.

Motors of this type are employed to oscillate or vibrate a metallic diaphragm which in turn generates the sound waves which constitute the audible warning signal. While the overall life expectancy of these motors is comparatively short, they must be absolutely reliable and function over a wide range of temperatures without substantial variation in the frequency of the vibration produced. A stable frequency is important further becausethese horns are usually employed in pairs with the frequency of each of the pair of horns being sufficiently different to give a characteristic beat note. Since the frequency of this beat note is equal to the difference in frequency of the two horns, a small drift in the frequency of either horn will produce a much larger drift in the frequency of the beat note.

The structure of this horn is best understood by reference to the drawing in which:

Figure l is a plan view of the horn motor, and

Figure 2 is a sectional view of the horn motor taken along the line 2-2 of Figure 1.

Turning first to Figure 2, the diaphragm is shown closing the lower portion of cup 11. It is the oscillations of this diaphragm 10 which produce the actual sound. Diaphragm 10 is weighted by slug 12 which lowers the natural frequency of oscillation of the system and forms an integral part of the magnetic circuit. This magnetic circuit comprises slug 12, cup 11, washer 13 and post 14.

Post 14 is surrounded by coil 15 which energizes the magnetic circuit. Coil 15 is in turn controlled by a buzzer or door-bell type circuit which includes contact points 16. The upper of contact points 16 is securely riveted to spring 17 and the lower of contact points 16 is fastened to rigid member 18. Rigid member 18 is electrically isolated from the remainder of the structure by insulators 19 and 20. Insulator 20 is similar in shape and coextensive with spring 17 and is centrally cut away to accommodate contact upper point 16. The electrical energy enters the unit through a connection made to the left end of rigid member 18, flows the length of rigid mcmber 18 to the lower one of contact points 16, hence to the upper one of contact points 16 along the length of spring 17 and hence through conductor 21 into coil 15. The circuit is completed through conductor 22 (Figure l) which is solidly grounded on cup 11.

Pin 23 is received axially in post 14 and supported at its lower end by the central portion of slug 12. The upper end of pin 23 contacts the outboard section of insulator 20. When electrical energy is applied to rigid member 18 and hence to coil 15, slug 12 and diaphragm 10 are attracted towards post 14. This movement of slug 12 in turn moves pin 23 axially and upwardly against insulator 20 which in turn flexes spring 17 upwards and spans; e rner 16 i? a s i f t e 116 n as is fi dl aa wa pset. return. and diaphragm ll) to the' norma llpd u ijsirepeatediiifthenei hborhoodrof400 e z se a' d i h ir I. 1 R -l e 4 3 W?" i e em: Pa 's Kiwi a... arcing due. to high voltage generated: by the. su en caiia setor'uielmagnetite lid. i As is riio 'r e clearlysho wn Figure" l, rigidriiember 18 is provided with two openings. Opening 25 is threaded to receive the screw which secures the necessary electrical connection. Opening 26 is provided just outside of the portion of rigid member 18 which is held in place by in sulators 19 and 20. Opening 27 is provided in tab 28 of washer 13 to enable the rapid and accurate adjustment of the spacing of the contact points 16 during assembly operation. From a study of Figure 1, it will be seen that tab 28 has been provided on washer 27 and that this tab 28 extends beyond spring 17, rigid member 18 and insulators 19 and 20 and forms extensions 29. After the motor has been finally assembled, the contact point spacing is readily and accurately adjusted by applying a special wrench to that portion of tab 28 which extends beyond rigid member 18, insulators 19 and 20 and spring 17 and bending tab 28 to rotate the entire contact assembly about an axis passing through opening 27 in tab 28. This opening 27 has been specifically provided to localize all bending at this particular locale during the adjusting operation. Opening 26 has similarly been provided so that should excessive force be accidently applied to rigid member 18, this member will bend across opening 26 which is advisedly made weaker than the metal of tab 28 adjacent opening 27 so that the adjustment of the contact points cannot so be disturbed.

I claim as my invention:

1. A vibratory horn motor comprising an electrical solenoid, a diaphragm operated by the said solenoid, a pin located in an axial opening in the solenoid and resting upon said diaphragm, a washer secured to the solenoid on the side remote from the diaphragm, a tab forming an extension of said washer, a rigid member bearing a contact point secured to said tab, a spring member bearing a contact member secured to said tab and resting upon said pin, said rigid member and spring member being electrically isolated from said tab, said tab being provided with integral extensions to enable said tab to be bent whereby the spacing between said pin and spring may be adjusted by rotation of the entire end of the tab.

2. A vibratory horn motor comprising an electrical solenoid, a diaphragm operated by said solenoid, a pin located in an axial opening in the solenoid and resting upon said diaphragm, said pin being movable axially in solenoid, a washer secured to the solenoid on the side remote from the diaphragm, a tab forming an extension of said washer, a rigid member bearing a contact point secured to said tab, a spring member bearing a contact member secured to said tab and resting upon said pin, said rigid member and spring member being electrically isolated from said tab, said tab being provided with integral extensions to enable said tab to be bent whereby the spacing between the pin and the spring may be adjusted by rotation of the entire end of the tab, said tab being further provided with an opening intermediate the washer and said extensions whereby bending of the tab is accurately localized.

3. A vibratory horn motor comprising an electrical solenoid, a diaphragm operated by said solenoid, a pin located in an axial opening in the solenoid and resting upon said diaphragm, said pin being movable axially in solenoid, a washer secured to the solenoid on the side of said washer, a rigid member bearing a contact point secured to said tab, a spring member bearing a contact member secured to said tab and resting upon said pin, said rigid member and spring member being electrically isolated from said tab, said tab being provided with integral extensions to enable said tab to be bent whereby the spacing between the pin and the spring may be adjusted by rotation of the entire end of the tab, said tab being further provided with an opening intermediate the washer and said extensions whereby bending of the tab is accurately localized, said rigid member being extended beyond the tab to form an electrical contact, the portion 4 of said rigid member extending beyond the tab being provided with a weakening aperture so that forces applied to the portion of the rigid member provided as an electrical contact will bend the electrical contact and 5 not the tab.

References Cited in the file of this patent UNITED STATES PATENTS

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