US2203420A - Warning signal - Google Patents

Description

June 4, 1940. T J. SCOFIELD ET AL WARNING SIGNAL Filed Oct. 2'7, 1957 ATT DHNEY Patented June 4, 1940 UNITED STATES 2,2t3A2b PATENT OFFIC.

WARNING SIGNAL tion of Ohio Application October 27, 1937, Serial No. 171,370

7 Claims.

This invention relates to improvements in a horn or warning signal for motor driven vehicles and which comprises a vibratory diaphragm operated by an electric motor of the magnetic type.

One of the objects of the invention is to provide an improved signaling device of the above mentioned class by simplifying and advancing the construction and relative arrangement of parts thereof.

A more specific object of the invention is to provide the electric circuit for a motor of the magnetic type with a relay switch whereby the relatively heavy current necessary for operating the motor will not be passed through the usual manually operated control switch connected in said circuit.

Another object of this invention is to provide a relay switch so connected in the electric circuit of the motor that the current controlled by closing of the manually operated switch will pass through the relay switch to effect initial energizing of the magnetic field of the motor and then the major portion of the field current is automatically shunted by said relay switch around the manually operated switch during the continued operation of the motor.

A further object of the invention is to utilize the magnetism produced in the field frame during the initial energizing of the magnetic field for automatically operating the relay switch.

These objects are attained by a mechanism illustrated in the accompanying drawing, in which:

Figure 1 is a perspective view of a warning signal embodying the various features of this invention.

Figure 2 is a plan view of the motor illustrated in Figure l, with the cover removed and on an enlarged scale.

Figure 3 is a perspective view of the field frame for the motor and the supporting brackets for said frame.

Figure 4 is a detailed vertical sectional view taken on line 44, Figure 2.

Figure 5 is a detailed vertical sectional view taken substantially on line 5-5, Figure 2.

Figure 6 is a wiring diagram showing the electric circuits included in the present invention.

The warning signal illustrated in the drawing is of general, well known construction in that a vibratory diaphragm is actuated by an electromagnetic motor of the reciprocating type and comprises two circular diaphragm case or housing sections 6 and 1 having a diaphragm 8 clamped between them. The front diaphragm housing section 6 carries a horn proper or projector l3 disposed substantially centrally thereof. The rear diaphragm housing section I constitutes a mounting plate for the electric motor which operates diaphragm 8. The electric motor includes an electro-magnet it having a field frame ll secured to the housing section 1 by a pair of supporting brackets 2! and 22 electrically welded or otherwise secured to said housing section. The frame [1 supports the usual preformed field coil 26. An armature 28, mounted over the outer or rear face of the frame I1, is operatively connected in the conventional manner to the diaphragm 8 by a stud or bolt 29 and a sleeve mounted on the bolt, as shown in Figure 5.

As usual in this type of motor, an automatic circuit breaker or interrupter is provided for intermittently opening and closing the circuit for coil 26. This breaker comprises a pair of contact arms 48 and 49 mounted in any suitable manner in a contact stack 50 connected to the housing section 7 at one side of the field frame H to be supported by said section in cooperative relation with each other and with the bolt 29. The contact arms 43 and 49 are connected in a starting circuit and an electric supply circuit for the motor and are operated in the usual manner by the armature 28 to effect intermittent energizing and de-energizing of the field coil 26 in synchronism with the movement of the diaphragm 8 toward and away from the field frame H.

The relay switch 5| comprising the novel features of this invention is of the singlepole, dou ble-throw type and includes a contact arm 52 pivotally connected intermediate its ends by a pin 53 to a bracket 54 which in turn is secured in electrically insulated spaced relation to the central portion of the housing section 1 at the side of the field frame ll to which the bracket 22 is secured as illustrated in Figures 2 and 5. The contact arm 52 is provided with a pair of contact points 56 and 57 positioned at either end thereof and which are adapted to engage contact points 58 and 59 secured to the housing section I and bracket 22 respectively. The contact point 58 is mounted in electrically insulated spaced relation to the housing section '1? in out ward space relation to the pivot 53 by screws Gil and insulating plates Bl as indicated in Figure 5. The other contact point 59 is secured to the bracket 22 in electrical connection therewith by means of screws 82 screw threaded in a lateral projection or shelf 63 formed integrally with bracket 22 intermediate the ends thereof as i1- lustrated in. Figure 3.

A spring 65 coiled upon the pin 53 has one end thereof engaging arm 52 and the other end contacting the adjacent insulating plate 6| yieldingly urging the arm 52 about the pin 53 in a direction to maintain the contact point 56 in engagement with the contact point 58. The arm 52 has connected therewith an armature 69 which extends outwardly from opposite sides of the arm in the plane of a pair of laterally disposed lugs or projections 51 formed integrally with the bracket 22 at opposite ends thereof as illustrated in Figure 3. The armature 66 is so connected With the arm 52 that when the contact point 56 is in engagement with the contact point 58 the ends thereof will be in alignment with the lugs 5'! and slightly spaced from the outer ends of said lugs as indicated in Figures 2 and 4.

The magnetic circuit breaker, and relay switch just described may be inclosed by 'a cover 68 which, as shown in Figures 1 and 5 is of usual construction, being an inverted cup shaped member having the marginal edge thereof surrounding the rear housing section I and resting upon the marginal edge portion of the front housing section 5, the latter housing section being of a slightly greater diameter than the rear housing section, as shown in Figure 5, for supporting the cover 58.

The operation of the circuits for the electrical magnet and relay switch will now be evident by referring to Figure 6 in connection with the remaining figures of the drawing. In the wiring diagram shown in Figure 6, the circuit for the electromagnet I5 is provided with a manually operated switch or push button S which is connected with one side of the battery B by ground G, the other side of the battery B is connected with one side of field coil 26 by wire 10. The other side of the field coil is connected by wire II with one of the contact arms as 49 of the circuit breaker. The other contact arm 48 of the circuit breaker is connected by wire 12 to arm 52 of the relay switch 5!. One contact member 58 of the switch 5|, is connected with the switch S by wire l3 while the other contact member 59 of said switch is connected to ground G. The wire 13 may be connected with the contact 58 through the medium of one of the screws 60, while the contact 59 is grounded to the bracket 22 which in turn is grounded to the case section 1 as illustrated in Figures 4 and 5.

It will now be evident that when the switch or push button S is closed the circuit is completed from battery 13 through wire 10, field coil 26 and wire H, to contact plate 49 and thence through the contact points 49 and 48' connected with contact arms 49 and 4B respectively, to contact arm 48. The current then passes through Wire 72 to switch 5| and thence through contact 58, wire 13 and switch S back to battery B. The current thus passing through the field coil 26 magnetizes the field frame H which draws the armature 28 toward said frame and produces, movement of the diaphragm 8 with said armature. The bracket 22 connected with field frame H is simultaneously magnetized with said field frame'and therefore draws the armature 66 connected with the switch arm 52, toward the lug members 61 of the bracket. The movement of the armature 28 toward the field frame I! breaks the starting circuit thus described, at the contact points 48' and 49', due to the movement of the contact arm 49 in a direction away from the contact arm 48. When the circuit is thus broken at contact points 48 and 49 the current continues to flow but at a lesser amount through a resistance R connected between wires II and 13. The resultant de-energizing of the field coil 26 releases the armature 28 whereupon the circuit is re-established through the contacts 48' and 49' and the armature 28 is again drawn to the case or frame H.

The current passing through coil 26 and magnetizing the case or frame I! will also magnetize the supporting bracket 22 and therefore attract armature 66 toward the end lugs 61 of the brackets 22. This movement of the armature 66 will rock the switch arm. 52 about the pivot 53, open the starting circuit at contact points 56 and 58 and close the current supply circuit by bringing contact points 5'! and 59 into engagement with each other. It will now be understood that the major portion of the current passing from the battery B through the coil 26 and contact arms 49 and 48 will flow from wire 12 and switch arm. 52 through contact points 51 and 59 to ground G and back to battery B. The switch contact 51 will be maintained in electrical connection with the contact 59 due to the residual magnetism in the bracket 22 and by the action of the relatively weak current passing through the coil 26 as determined by resistance R as long as the switch S is maintained closed.

It will now be apparent that the relay switch 5! will be maintained in position for shunting the current around the switch S after the initial closing of the later switch and that the operation of the armature 28 and diaphragm 8 connected therewith as described above, is rapidly repeated as long as the horn button S is depressed resulting in the emission of an audible warning signal through the projector l3. As soon as the switch S is released and assumes the open position, the demagnetization of the frame l1 and bracket 22 resulting therefrom will release the armature 66 and permit the switch arm to be actuated by spring 65 to restore the engagement of contact point 56 with contact point 58 and thereby separate contact point 57 from contact point 59.

While the construction and operation described herein are particularly simple, practical, and efiicient it will be evident that various modifications and changes may be made therein without departing from the spirit of the invention as set forth in the appended claims.

We claim:

1. In a warning signal having a vibratory diaphragm actuated by an electro-magnetic motor of the reciprocating type controlled by a normally opened push button switch and wherein the current supply circuit for said motor in-i cludes a battery, and an automatic circuit breaker is connected in series with the field coil of the motor, in combination, a double throw switch having a movable contact arm connected in said circuit, said switch having one contact element thereof connected with the battery in series with said push button, a second contact element of said switch being connected directly to said battery, means for operating the contact arm for opening the circuit at the first contact element and closing said circuit at said second contact element including an armature connected with said contact arm and normally arranged in slightly spaced relation to the field frame of the motor to be attracted by magnetism produced in said frame during the energizing of the field coil, and a resistance connected in said circuits between the field coil and the push button in shunt relation with the double throw switch and said automatic circuit breaker to maintain sufli cient magnetism in said field frame when the motor circuit is broken at the automatic circuit breaker for holding the double throvw switch closed at the second contact element during the period the push button is maintained closed.

2. In a device of the class described, the combination with the field frame of an electro-ma-gnetic motor of the reciprocating type and an electrical circuit including a manually operated switch for said motor, a support for the motor, a bracket for connecting the field frame to said support, said bracket being in electrical contact with said field frame, a double throw switch connected in the motor circuit, said latter switch being mounted on the support in insulated spaced relation thereto and having one stationary contact element thereof connected withone side of a source of potential in series with the manually operated switch, a second stationary contact element of said double throw switch being electrically connected directly with said one side of the source of potential, means for operating the double throw switch including an armature connected with said switch and arranged to normally extend in slightly spaced relation to the bracket so as to be attracted by magnetism produced in said bracket during the energizing of the field frame, and a resistance so connected in said circuit between the field coil of the motor and the manually operated switch that a sufiicient magnetism is maintained in the field frame and bracket during the operation of the motor to hold the armature in position to maintain the double throw switch closed at the second contact element during the period the manually operated switch is maintained closed. 7

3. In a warning signal of the class having a vibratory diaphragm actuated by an electric motor of the reciprocating magnetic type, in combination, an electric supply circuit for said motor including a source of potential, a field coil and an automatic circuit breaker connected in series therein, support for said diaphragm and field coil including a mounting plate and field frame, said plate being electrically connected with the field frame, a starting circuit including a manually operated switch connected with said source of potential, a double throw switch supported by said plate and having its movable member and one stationary contact insulated therefrom, the movable member being connected in series with the field coil and circuit breaker, the stationary contacts of said latter switch including a first contact connected with the source of potential in series with the manually operated switch and a second contact connected directly with the source of potential, the movable member being biased toward the first contact, means for operating the double throw switch when the field coil is energized including an armature connected with said switch and normally positioned in slightly spaced relation with the field frame to be actuated by magnetism produced in said frame by the energizing of said field coil, and a resistance connected in the supply circuit and starting circuit between the field coil and said manually operated switch in shunt relation with said double throw switch and circuit breaker.

4. In a warning signal wherein a motor includes a field coil, a frame therefor, a battery, a normally opened push button switch, an armature associated with said frame and operatively connected with the sound producing element,

and wherein an automatic circuit interrupter is mounted adjacent the armature to be actuated thereby, in combination, a switch element connected in a circuit of the motor in series with the circuit interrupter and with said field coil and having a first circuit normally connected in series with said push button, a second circuit of said switch element being connected directly with the battery, an armature for said switch element arranged adjacent the field frame to be moved to a second position by the magnetism in said frame for actuating the switch element to open said first circuit and to close said second circuit, and a resistance connected in said first circuit between the coil and push button to form a shunt around the circuit interrupter and maintain the field frame sufficiently magnetized to hold the armature in said second position and thus maintain said second circuit closed throughout the period the push button is maintained closed.

5. In an audible warning signal of the class wherein an electro-magnetic motor is provided with a current supply circuit having a battery, a field coil and an automatic circuit interrupter connected in series therein and a starting circuit including a normally opened push button switch mounted in series with said battery, in combination, a movable contact arm having one of the contacts thereof connected in series with the field coil of said motor and said circuit interrupter, a second contact of said arm being connected with the push button and a third contact of said arm being connected directly with the battery, means actuated by magnetism produced in said frame when the field coil is energized for actuating said contact arm, and a resistance connected in said supply and starting circuits between the field coil and push button to form a shunt around the interrupter and said third contact of the contact arm for maintaining the field frame partially energized when the circuit is broken by said circuit interrupter.

6. In a device .of the class described, in combination, normally open starting, shunt resistor and current supply circuits, an electro-magnetic motor of the reciprocating type included in and common to each of said circuits, means including a relay connected in the starting and current supply circuits to normally maintain said starting circuit closed and said current supply circuit open when said relay is in a first position, said relay being so constructed and arranged that the coil of the motor functions as the coil of said relay and the armature of said relay is actuated to place the relay in a second position during the initial flow of current through said coil upon closing of the starting circuit to effect opening of the starting circuit and closing of the current supply circuit, and a manually operated switch for initially closing the starting circuit and to simultaneously close said shunt resistor circuit and thus maintain the motor magnet partially energized when the starting circuit is opened by said relay, whereby the relay is maintained in said second position as long as the shunt resistor circuit is maintained closed by the manually operated switch.

7. In a device of the character described having an electro-magnetic motor of the reciprocating type, in combination, electric circuits for controlling and operating said motor including normally open starting, holding and current supply circuits, a push button switch included in and common to the starting and holding circuits for simultaneously opening and closing the same,

means including a movable contact arm mounted in and common to the starting and the current supply circuits for opening and closing the same, said contact arm being normally maintained in a first position to maintain the starting circuit closed therethrough and the current supplying circuit open, and means including an armature connected with said contact arm and actuated by magnetism in the field frame of the motor for in bringing the contact arm to a second position to effect opening of the starting circuit and closing of the current supply circuit, said holding circuit being arranged so as to maintain the field frame of the motor partially energized and the armature to be maintained thereby in said second position during the period said holding circuit is maintained closed by the push button.

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