US3358160A - Flashers - Google Patents

Description

12, 1957 A. F. BLEIWEISS ETAL 3,358,160

FLASHERS 2 Sheets-Sheet 1 Filed March 24, 1966 .Pzomm ATTORNEYS United States Patent 3,358,160 FLASHERS Arthur F. Bleiweiss, New York, and George Colombo,

East Rockaway, N.Y., and John B. Dickson, Clewiston,

Fla., assignors to Lehigh Valley Industries, Inc., a corporation of Delaware Filed Mar. 24, 1966, Ser. No. 537,208 7 Claims. (Cl. 307-132) ABSTRACT OF THE DISCLOSURE A flasher such as for automobile signal lamps or the like in which flashing is the result of the making and breaking of a load circuit in response to sequential heating and cooling of a snap element and pull element assembly. A shunt circuit is provided for shunting at least a portion of the load from the snap element and pull element assembly in order to avoid unnecessary heating of the assembly.

This application is a continuation-in-part of copending application Ser. No. 230,050 filed Oct. 12, 1962, now Patent No. 3,246,181 granted Apr. 12, 1966. This invention relates to a flasher generally of the type known as a thermomotive flasher commonly used in automotive vehicle signalling systems for flashing the signal lamps of vehicles to indicate left or right turns or a hazard or emergency situation.

The invention is more specifically directed to the socalled snap element type flasher which snaps between a restored and a constrained position on expansion and contraction of a pull element as a result of heating and cooling of the pull element.

A principal object of this invention is the construction of an improved flasher whereby current flow through the snap element is substantially reduced to thereby improve the life operating characteristics of the flasher resultant from cooler operation of the snap element. Other objects will hereafter become apparent.

Generally speaking, in accordance with the invention, a snap element type flasher flashes the vehicle lamps connected in the load circuit by the cyclical opening and closing of contacts in response to a snapping action of the snap element. During the load carrying cycle a low resistance bypass or shunt circuit is provided to reduce or eliminate the load current carrying function of the snap element resulting in cooler operation of the snap element. This is especially important when high load currents due to multiple bulb flashing are involved since the heating of the snap element can effect a deterioration of the physical properties and thereby the operating characteristics to thereby otherwise reduce the effective life of the flasher. v

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

[For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a schematic representation of one type of flasher constructed in accordance with the invention connected into a typical signalling system;

FIG. 2 is a schematic representation of a variable load type of flasher constructed in accordance with the invention;

FIG. 3 is a schematic representation of a variable load flasher having a pilot relay, constructed in accordance with the invention;

FIG. 4 is a schematic representation of another type of flasher constructed in accordance with the invention;

FIG. 5 is a schematic representation of a fixed load flasher constructed in accordance with the invention; and

FIG. 6 is a schematic representation of another form of fixed load flasher constructed in accordance with the invention.

Referring now to FIG. 1, one embodiment of the instant invention is disclosed in conjunction with what may be termed a variable load flasher having normally closed contacts. By this is meant that the flashing rate of the flasher is predetermined in accordance with the desired flasher characteristics and does not vary substantially with the load applied. With the normally closed contacts, the signal lamps are lighted the instant the circuit is completed by closure of the appropriate switch, the turn signal switch for example, with flashing resulting from the opening and closing of the flasher contacts.

The flashers schematically depicted in the drawings incorporate a vane and pull ribbon of a type known in the art such as that disclosed in U.S. Patent 2,756,304 issued July 24, 1956, to James W. Welsh. Thus a detailed description of the vane construction, pull ribbon attachment and mounting arrangement is deemed unnecessary. Suflice it to say that the vane has a restored position and a constrained position, the vane being normally held in the constrained position by the pull ribbon attached thereto. On heating of the pull ribbon, the pull ribbon expands permitting the vane to snap to the restored position. As the pull ribbon cools, it contracts thereby causing the vane to snap to the constrained position. Sequential snapping of the vane results from sequential heating and cooling of the pull ribbon. A moveable contact is mounted for movement with the vane and pull ribbon assembly and may be mounted either on the vane or on the pull ribbon. The moveable contact is mounted relative to a fixed contact through which it makes and breaks a circuit as the vane snaps between its two positions. The cooled condition of the pull ribbon with the vane thereby constrained is considered the normal position and a flasher having the fixed and moveable contacts in engagement in the normal position is considered a normally closed flasher. Conversely, if the contacts are out of engagement in the normal posi tion, the flasher is considered a normally open flasher.

Referring to FIG. 1, the flasher shown therein is a normally closed variable load flasher of the type disclosed in the aforesaid US. application Ser. No. 230,050 filed Oct. 12, 1962, of which this application is a continuationin-part. A typical automotive signalling system is shown consisting of a grounded source of potential shown as a battery 11 and a set of signal lights 12. In passenger vehicles, there is usually provided one left and one right front signal light and one or more left and right rear signal lights. In the example shown, each of the left and right rear signals consists of three bulbs which is representative of the trend in passenger vehicle signalling systems. A turn signal switch is schematically represented by the indicia TS for selective connection of the circuit to either the left or right signal lamps for selectively signalling a left or a right turn. A hazard warning switch HS is also shown for simultaneously connecting all signal lamps into the circuit whereby all signal lamps may be simultaneously flashed to provide a hazard or emergency warning. Thus, during a turn signal operation, four bulbs are flashed in the example shown while during hazard warning eight bulbs are flashed. Obviously, the greater the number of bulbs connected in the circuit, the higher the current in the load circuit.

For simplicity, the battery is shown as being connected to the input terminal X and the signal lamps connected to the load terminal L. The flasher to be hereafter described is generally provided with corresponding terminals for connection into the circuit. The connections to the X and L terminals are shown by way of example, it being understood that the X and L terminals could be reversed without changing the operation ofthe various disclosed circuits.

The flasher is indicated generally at 13. A vane or snap action member 14 is supported by a fixed mounting 15 and is provided with a pull ribbon or heat responsive element 16 for releasing and constraining the vane in response to heating and cooling of the pull ribbon as described above. A moveable contact 17 is carried by the vane proximate to and normally engaged with a fixed contact 18. Moveable contact 17 is electrically connected to load terminal L through a flexible connection 19 and fixed contact 18 is electrically connected to the input terminal X by means of a conductor 21. In this type of variable load normally closed flasher, a relay coil 22 is in series between the X terminal and the fixed contact.

A heater winding 23 surrounds the pull ribbon in heat transfer relationship and has an end electrically connected thereto or to any other point of battery potential. The other end is serially connected to ground terminal G through normally open contacts 24 controlled by relay coil 22.

With the aforesaid flasher construction, the high load current required for illuminating four or eight signal lamps is shunted around the vane. This may best be understood by a description of the operation of the circuit of FIG. 1. In the condition .shown in the figure, the circuit is inoperative due to the open turn signal or hazard switch as well as the normally open contacts 24. On actuation of the turn signal or hazard switch, the battery potential is immediately applied across the selected signal lamps and current flows through relay coil '22 and contacts 17 and '18 to illuminate the signal lamps. The magnitude of current flow is proportional to the number of signal lamps in the circuit. The current passing through relay coil 22 also energizes the coil to close contacts 24 to thereby complete a parallel circuit through contacts 17 and 18, vane 14, pull ribbon 16, heater winding 23, contacts 24 and the ground. The current flow through the parallel circuit is quite small as compared with the current flow through the load circuit and depends "on the resistance of the heater Winding and any resistance in the ground circuit. Note that a pilot lamp can be inserted in the ground circuit, if desired. The current flow through resistance heater winding '23 heats the pull ribbon causing it to expand whereby the vane snaps to a restored position to physically inove moveable contact 17 out of engagement with fixed contact 18. This breaks the load circuit to extinguish the signal lamps and also opens the circuit through the heating winding to permit the pull ribbon to cool down. Atthe same time, contacts 24 open as a result of the open circuit through the :relay coil. When the pull ribbon has cooled, it snaps the vane to the constrained position to close contacts 17 and 18 and the flashing cycle repeats so long as the turn signal or hazard switch remains closed.

The heating rate of the pull ribbon is proportional to the current in the ground circuit and the flashing rate is thereby not substantially affected by the load in the load circuit. More importantly, with respect to this application, only the very small current in the ground circuit travels through the vane, and thus the heating of the vane due to its inherent resistance is minimized. The high load current passes directly from contact 18 to contact .17 and thence to terminal L and thereby does not heat the vane in response to the high load current. It has been found that heating of the vane, especially with high currents from high loads, causes the actuating properties of the vane to deteriorate during extended operation. The heating of the vane serves no useful purpose and thus the cooler operation of the vane as described in connection with FIG. 1 results in the maintenance of the proper operating characteristics over "a longer life of the flasher.

In previous variable load flashers, the destructive eliect of the heating of the vane as a result of the high load currents passing therethrough placed a limit on the variable load. With this invention, the upper limit is eliminated or substantially raised and thus a great many bulbs can be flashed without changing the operating characteristics or substantially reducing flasher life.

The principle of this invention is equally applicable to other types of thermornotive flashers and various embodiments are shown by way of example in :FIGS. 2 through 6. Note that in these figures, a simplified schematic diagram showing only the flasher with the X and L and, where appropriate, :6 and P terminals. The .source of potential, signal lamp circuit and ground and pilot circuits are conventional.

Referring to FIG. 2, there .is shown what may be termed a variable load flasher with normally open contacts. Fixed contact 31 is electrically connected to the input terminal X as well as to heater winding 33 which is in heat transfer relationship and has one end connected to pull ribbon 1'6. Vane 14.is provided with the usual fixed mounting 15 which may or may not act as an electrical conductor, as desired. -A moveable contact 32 carried by the vane is electrically connected at one end to a flexible shunting connection 34 in circuit with fixed mounting 15 and the load terminal. When the load circuit is completed to the signal lamps, a small current flows from the X terminal through fixed contact 31, heater winding 33, pull ribbon 16, vane 14, fixed mounting 15 and the load terminal. Due to the resistance of the heater winding, the current flow is quite small and insuflicient to illuminate the signal lamps. The low current also has little heating effect on the vane. The current is, however, sufficient to heat the pull ribbon to cause the vane 'to snap from the constrained to the restored position, thereby closing the contacts 31 and '32. At this instant, the high load current drawn by the signal lamps flows through the circuit to illuminate the signal lamps. With flexible shunting connection 34, a substantial portion of the high load travels through contacts 31 and 32 and the shunt circuit, thereby substantially bypassing the vane to prevent excessive heating of the vane as a result of the load current. The shunting of the vane in the circuit shown also concurrently efiects a shunting of the heater winding to further accelerate cooling of the pull ribbon to return the vane to the constrained position, resulting in cycling of the flasher. By shunting the vane during the application of heavy load currents, improved lite characteristics of the vane and flasher result, as described above.

Turning now to FIG. 3, there is shown a flasher of the type shown in FIG. 2 but provided with a pilot relay for controlling the operation of normally open contacts 36 in order to provide a pilot signal for the vehicle operator. The circuit operates identically as described inconnection with FIG. 2 with the addition that, on closing of the contacts 31 and 32, the load current, which is shunted through flexible shunting connection 34, energizes relay coil 35 to close contacts 36, thereby providing a parallel circuit for the pilot terminal. The connection of the pilot terminal serially with a pilot lamp to ground is conventional.

FIG. 4 schematically represents what is normally considered a fixed load flasher with a contact on the pull ribbon. The heating of pull ribbon 16 is efifected by the load current travelling therethrough and thus the heating and cooling rate depends on the current drawn by the load circuit. In order to obtain the proper operating characteristics, this type of flasher is designed for any pre selected load. The standard circuit includes the X terminal, fixed contact 41, moveable contact 42, pull ribbon 16, vane 14, fixed mounting 15 and load L Load L is .a fixed load and the flasher has been designed in accordance with the known load L When a switch in load circuit L is closed, current flows through the normally closed con tacts, the pull ribbon and the vane and the heating of the pull ribbon causes it to expand to permit the vane to snap to the restored position thereby opening the contacts and breaking the circuit. When the circuit is broken, the pull ribbon cools down and the flasher thereby cycles. An additional load circuit L may be provided connected to moveable contact 42 through a flexible shunting connection 43. When the contacts are closed, heavy loads may be applied in load circuit L through the closed contacts, and such loads will be substantially independent of the vane and pull ribbon to thereby eliminate or minimize heating effect. The heating currents travelling through the pull ribbon and vane will depend primarily on load L Not only does this arrangement permit such a flasher to be used for high loads while maintaining heating of the vane to a minimum, but said flasher could also be used for variable loads 50 long as a fixed load is connected into load circuit L Variations in the load in L would have substantially little effect on the flashing rate of the flasher.

Another embodiment of a fixed load flasher with contact on pull ribbon is shown in FIG. 5 for use with a relatively high fixed load. A flexible resistance connection 45 is connected between moveable contact 42 and fixed mounting 15 in order to divide the load current. Due to the resistance of flexible connection 45, the pull ribbon and vane will not be completely shunted and sufficient current will pass therethrough in order to heat the pull ribbon so that it may cycle normally. The load current would be the summation of the current through the pull ribbon and vane and the current through the resistance connection. Based on a nominal voltage, the required current through the pull ribbon and vane would be known in order to provide the preselected flashing rate, and thus the resistance of the pull ribbon and vane could be simply calculated in accordance with the formula E=IR. The total load being known the current through the flexible shunt could be calculated whereby the required resistance of flexible connection 45 for the requisite current through the parallel resistance circuit could be simply calculated.

A modification of the FIG. 5 flasher is shown in FIG. 6 wherein a fixed load flasher is provided with contact on the vane. Fixed contact 51 is normally engaged with moveable contact 52 and a flexible connection 53 connects pull ribbon 16 to the load terminal. Moveable contact 52 is connected to the load terminal through a flexible resistance 54. Here again the load circuit is divided so that a current based on the resistance of the vane and pull rib-hon effects heating of the pull ribbon through contacts 51 and 52, vane 14, pull ribbon 16, and flexible connection 53. A greater portion of the load current passes directly to the load contact from moveable contact 52 through resistance 54. Calculations of currents and resistance values would be accomplished as described in connection with FIG. 5.

While the FIG. 5 and FIG. 6 flashers are of the fixed load type, such flashers can handle load currents higher than previously possible since the entire load current does not pass through the vane and pull ribbon. This permits cooler operation of the vane with the resultant longer life.

With the aforesaid described embodiment, it will be apparent that this invention may readily be adapted for use with ahnost any type of thermomotive flasher. A principal feature is to provide means whereby some or all of the load current is shunted from the vane in order to minimize heating of the vane which undesirably affects the snapping characteristics thereof.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efliciently attained and, since certain changes may be made in the constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. A thermomotive flasher comprising a snap action member, a heat responsive element carried by said snap action member for controlling the snapping thereof in response to heating and cooling of said heat responsive element, said snap action member and heat responsive element defining an assembly, a fixed contact, a contact mounted on said assembly and being movable thereby upon snapping of said snap action member, said movable contact being engageable with and disengageable from said fixed contact, a high current load circuit independent of said assembly, said load circuit including an input terminal connected to one of said contacts and a load terminal connected to the other of said contacts, for connecting a source of potential to a load when said contacts are in engagement, and a low current heating circuit including said snap action member and said heat responsive element for controlling the heating of said heat responsive element, said low current heating circuit being cyclically controlled in response to engagement and disengagement of said fixed and movable contacts for effecting heating and cooling of said heat responsive element, whereby only the currents in the heating circuit pass through said assembly during the heating cycle and the currents in the load circuit by-pass said assembly during the load cycle.

2. A thermomotive flasher as claimed in claim 1 wherein said movable contact is carried by said snap action member for movement therewith and is mounted in normally open relationship with respect to said fixed contact, and said movable contact and said snap action member are electrically connected to one of said terminals in parallel circuits, said heating circuit comprising a resistance element in heat transfer relationship with said heat responsive element and having one end connected at the potential of said heat responsive element, the other end of said resistance element being connected at the potential of said fixed contact.

3. A thermomotive flasher as claimed in claim 2 wherein a relay coil is serially connected between one of said terminals and one of said contacts, and including a pair of normally open contacts controlled by energization of said relay coil connected between the other of said terminals and a third terminal of different potential.

4. A thermomotive flasher as claimed in claim 1 wherein said movable contact is mounted to said heat responsive element for movement therewith and electrically connected thereto, said contacts being normally closed, and including a third terminal electrically connected to said snap action member and forminga part of said heating circuit.

5. A thermomotive flasher as claimed in claim 1 wherein said movable contact is mounted to said heat responsive element for movement therewith and electrically connected thereto, said contacts being normally closed, one of said terminals being electrically connected to said snap action member, said load circuit including a resistance member connected between said movable contact and said one terminal.

6. A thermomotive flasher as claimed in claim 1 wherein said movable contact is carried by said snap action member and electrically connected thereto, said contacts being normally closed, one of said terminals being electrically connected to said heat responsive element, said load circuit including a resistance member connected between said movable contact and said one terminal.

7. -A thermomotive flasher as claimed in claim 1 wherein said contacts are normally closed, and said heating 7 8 circuit includes a third terminal electrically connected to 2,689,289 9/1954 Bell. said assembly. 4 2,715,187 8/1955 Schmidinger 307132 References Cllted 2,767,333 10/1956 *Grech 307-132 UNITED STATES PATENTS 3,246,181 4/1966 Bleiweiss Cl'al. 307 132 2,644,899 7/1953 Peery 307-432 5 Y Y 2,648,059 8/1953 Hostetler 315-83 XR CRIS RADER, P'imary Examine" 2,672,563 3/1954 Boddy 307132 T. B. JOIKE, Assistant Examiner.

Claims (1)

1. A THERMOMOTIVE FLASHER COMPRISING A SNAP ACTION MEMBER, A HEAT RESPONSIVE ELEMENT CARRIED BY SAID SNAP ACTION MEMBER FOR CONTROLLING THE SNAPPING THEREOF IN RESPONSE TO HEATING AND COOLING OF SAID HEAT RESPONSIVE ELEMENT, SAID SNAP ACTION MEMBER AND HEAT RESPONSIVE ELEMENT DEFINING AN ASSEMBLY, A FIXED CONTACT, A CONTACT MOUNTED ON SAID ASSEMBLY AND BEING MOVABLE THEREBY UPON SNAPPING OF SAID SNAP ACTION MEMBER, SAID MOVABLE CONTACT BEING ENGAGEABLE WITH AND DISENGAGEABLE FROM SAID FIXED CONTACT, A HIGH CURRENT LOAD CIRCUIT INDEPENDENT OF SAID ASSEMBLY, SAID LOAD CIRCUIT INCLUDING AN INPUT TERMINAL CONNECTED TO ONE OF SAID CONTACTS AND A LOAD TERMINAL CONNECTED TO THE OTHER OF SAID CONTACTS, FOR CONNECTING A SOURCE OF POTENTIAL TO A LOAD WHEN SAID CONTACTS ARE IN ENGAGEMENT, AND A LOW CURRENT HEATING CIRCUIT INCLUDING SAID SNAP ACTION MEMBER AND SAID HEAT RESPONSIVE ELEMENT FOR CONTROLLING THE HEATING OF SAID HEAT RESPONSIVE ELEMENT, SAID LOW CURRENT HEATING CIRCUIT BEING CYCLICALLY CONTROLLED IN RESPONSE TO ENGAGEMENT AND DISENGAGEMENT OF SAID FIXED AND MOVABLE CONTACTS FOR EFFECTING HEATING AND COOLING OF SAID HEAT RESPONSIVE ELEMENT, WHEREBY ONLY THE CURRENTS IN THE HEATING CIRCUIT PASS THROUGH SAID ASSEMBLY DURING THE HEATING CYCLE AND THE CURRENTS IN THE LOAD CIRCUIT BY-PASS SAID ASSEMBLY DURING THE LOAD CYCLE.

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