US2067057A - Automatic safety switch for vehicles - Google Patents

Description

Jan. '5 1937.

E. D. LAWSON AUTOMATIC SAFETY SWITCH FOR VEHICLES Filed April 18, 1955 Patented Jan. 5, 193? LWMS'Z AUTOMATEU SAFETY SWHTCH FQR VEHICLES Edward D. Lawson, Park Ridge, llli. Application April 18, 1935, Serial No. 16,986

9 Claims.

This invention relates to improvements in automatic safety switch for vehicles and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

One of the objects of the invention is to provide a switch for use in connection with the ignition and other electrical circuits of an automotive vehicle, and which shall automatically break said circuit or circuits should the vehicle turn over in any way beyond some predetermined angle with the-result that all circuits being dead, the engine will stop and the danger of fire from all electrical sources will be eliminated.

Another object of the invention is to provide a switch of this kind which shall be proof against premature operation due to the jarring and jolting that the associated vehicle may receive under extremely adverse road conditions.

A further object of the invention is to provide a switch which may be shipped with safety to the user and may be applied to a vehicle without requiring adjustments or alterations of any kind before its application to said vehicle.

Still another object of the invention is to pro- 5 vide a switch of this kind including a pair of oppositely diverging mercury tubes and relatively long associated electrodes, the lower portions of which are so disposed in the mercury of the associated tube as to insure the ample bathing of 30 upper portions of the electrodes with mercury to keep the circuit closed during the jarring and jolting of the vehicle should the jarring and jolting be severe enough to cause the mercury to rise in its tube.

35 Still a further object of the invention is to provide a switch of this kind comprising a pair of inclined mercury tubes and associated electrodes, each tube including a surge chamber extension through which the electrodes enter the tube, there 40 being associated with each surge chamber, a deflector for directing mercury thereinto and thereby to limit mercury movement in response to vehicle jarring andjolting, to one which cannot break the circuit controlled by the switch,

45 unless the vehicle turns or tips over beyond-some predetermined angle.

Again, it is an object of the invention to provide an improved cushion mounting for the mercury tubes of the switch so that they will not 50 become broken through accident or otherwise.

The above mentioned objects of the invention, as well as others, will more fully appear as I proceed with my specification.

In the drawing 55 Fig. 1 is a longitudinal vertical sectional view on a somewhat enlarged scale, through a switch made in accordance with one embodiment of the invention, as taken on the line l-l of Fig. 2.

Fig. 2 is a transverse vertical sectional view through the switch as taken on the line 22 of 5 Fig. 1.

Fig. 3 is a perspective view of one of a pair of cushioning elements employed in the switch and which will be referred to in more detail later.

Referring now in detail to that embodiment of 10 the invention, illustrated in the accompanying drawing 5 indicates, as a whole, the casing for the switch which is substantially of an inverted triangular shape. Preferably the casing comprises a. body 15 6 of sheet material and a cover i therefor also preferably of sheet material, the cover and body having a beaded over marginal flange extension 8. In said flange extension are openings 9, as indicated in dotted lines-in Fig. 1, to receive fas- 20 tening devices whereby the switch may be secured in place upon the associated vehicle. When in place upon the vehicle, the switch will occupy a vertical position extending transversely of the vehicle.

The interior of the casing is substantially filled by a cushion element It that encloses a pair of mercury tubes HH disposed at opposite angles inclined from the perpendicular. At these angles, said tubes stand parallel with the upwardly and oppositely inclined bottom walls of the casing. Each tube is provided with a substantially perpendicular surge chamber I 2 and in each tube is a quantity of mercury it which, of course, seeks its normal position at the bottom end of each tube as best appears in Fig. 1.

In each surge chamber is sealed a pair of electrodes l4 and I 5 respectively, the bottom ends l4a--l 5a of which are bent to follow the inclination of the tube and to extend into the mercury in the respective tubes so as to be electrically connected thereby.

The electrodes M and [5 have end portions disposed outside the sealed ends of the surge chamber extension and the electrode M of one tube is electrically connected to the electrode M of the other tube by a flexible conductor l6 such as a piece of stranded wire. The end portion of each electrode l5 has connected thereto one end of a flexible conductor H, the other end of said conductor being connected to a flexible terminal strip 18. Each terminal strip which is made of a thin sheet metal is secured to an associated terminal post I9 in the form of a screw that extends up through an associated opening in the horizontal top wall of the casing body. A lock nut 20 secures each screw in place and also on each screw is a clamp nut 2| whereby a conductor 22 may be attached, said conductors forming a part of the circuit to be controlled.

Each tube and its surge extension chamber is evacuated and preferably filled with an inert gas, thereby eliminating the possibility of corrosion of the terminals or electroplating the interior surface of the tube with a mercury film that might render the switch inoperative for its intended purpose under certain conditions.

As an added precaution to insure perfect contact under the most abnormal operating conditions as when the vehicle is subjected to severe and unusual jolting, means are provided to defiect and momentarily trap the moving mercury in the surge chamber. Such means comprises a defiector member 23 fixed to each electrode l5 near its bent bottom end I5a.

When the jolting the vehicle receives is of such magnitude as to cause the mercury in either tube to move or surge upwardly therein, the mercury will engage the associated deflector and will be deflected or turned into the adjacent surge chamber. This action assures constant submersion of the conductors in the mercury under all-operating conditions no matter how active and agitated the mercury may become. Any mercury entering the surge chamber in this manner, of course, automatically returns to its well at the bottom of the associated tube, bathing the electrodes with mercury on said return.

The mercury tubes described are cushioned in the casing in a manner protecting them against damage due to jolting and the means therefor is as follows- Within the casing so as substantially to fill the same is a pair of cushion elements 24-24 composed of a relatively soft rubber. The construction is best shown in perspective in Fig. 3. Each element 24 is provided in one face, with recesses Ila, Ila, Him and Ha. respectively, which coact to receive the tubes l l, surge chamber extensions l2 and conductors l6 and H respectively, when said elements are arranged with their recessed faces engaging each other as best shown in Fig. 2.

In the assembly of the structure described, the tubes and conductors are disposed in the recesses provided therefor in a pair of cushion elements arranged face to face. When the tubes are thus disposed, the terminal clips 18 extend up between the top margins of the cushion elements. With the parts in this position, they are placed within a casing body with the screws [9 extending upwardly through the associated openings in the top wall of the casing body and then the lock nuts 20 are applied.

A cover 1 is then applied and its margins are preferably flanged over the flange extension of the cover plate. By the application of the cover plate, the cushion elements are very slightly compressed and thisassures that they will securely hold the tubes in place and yet protect them against damage.

It is pointed out that the conductors 22 preferably form a part of the electrical system of the vehicle to which the switch is attached. Should the vehicle, through accident, turn over sidewise or endwise, it is apparent that the mercury in one or both tubes will run toward the opposite end of the tube. This will leave the electrode ends bare or free of mercury so that they are electrically disconnected. Therefore, the circuit of which the conductors form a part, is broken, thereby stopping the engine and making all parts electrically dead. Thus should fuel be spilled when the vehicle turns over, it will not become ignited and cause a fire.

When the vehicle is righted, after having been turned over, the parts of the switch automatically return to their operative position.

As result of disposing the two tubes as described, several advantages flow. The tubes can be made to contain an equal amount of mercury and this overcomes excessive surging back and forth that would take place in a continuous V or U shaped tube. This is a fact because in either V or U shaped tubes, the motion of the mercury, by even a slight movement of the vehicle, tends to become violent through inertia forces set up by its own weight notwithstanding the provision in such tubes of dampers or baffles in an attempt to overcome this objection.

With the two tubes disposed as shown and described herein, the mercury rests quietly in its own tube end or well. In order to start the mercury up the tube, it would be necessary to exert considerable force and even then the long electrodes extending down into the tube end or well will be washed with rising mercury forming a perfect contact even before the deflectors 23 and surge chambers start to function as auxiliary safety factors.

' The mercury tubes are enclosed in the rubber cushion element in such a manner as will insure the tubes remaining in their proper position. They are thus protected by said elements against strain and damage. Due to the manner in which the casing is sealed, the switch is not only foolproofv but is also oil and dust-proof. Again, the switch is not affected by normal engine operating temperature, oil, vapor, gas, moisture, climatic conditions or different altitudes.

While in describing the invention, 1'. have referred in detail to the form, arrangement and construction of the variousparts thereof, the same is to be considered only in an illustrative sense. Hence, I do not wish to be limited to such details except as may be specifically set forth in the appended claims.

I claim as my invention-- 1. A switch of the kind described embodying therein a, pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a pair of electrodes associated with each tube and opening thereinto to engage in the mercury in the respective tubes, a disc carried by one electrode of each pair above the mercury in the associated tube, and means connecting one electrode in each tube together, the other electrodes for both tubes being adapted for connection in the circuit to be controlled.

2. A switch of the kind described embodying therein a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a surge chamber extension on each tube and arranged at an angle thereto, a pair of electrodes associated with each tube and opening thereinto to' have portions engaged in the mercury and other portions arranged in the surge chamber and means for connecting one electrode in each tube together, the other electrodes for both tubes being adapted for connection in the circuit to be controlled.

3. A switch of the kind described embodying therein a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a surge chamber extension on each tube and arranged at an angle thereto, a pair of electrodes associated with each tube and opening thereinto to have portions engaged in the mercury and other portions arranged in the surge chamber, means in each tube and arranged to deflect the mercury therein, into the associated surge chamber extension when said tube is tipped into that position causing the mercury to flow toward the other end of the tube, and means connecting one electrode in each tube together, the other electrodes for both tubes being adapted for connection in an associated circuit.

4. A switch of the kind described embodying therein a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a pair of electrodes associated with each tube and having one end normally disposed in the mercury in the associated tube and having the other end opening through a portion of the associated tube, a disc carried by one electrode of each pair above the mercury in the associated tube, and means connecting one electrode in each tube together, the other electrodes of both tubes being adapted for connection in the circuit to be controlled.

5. A switch of the kind described embodying therein. a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a surge chamber extension on each tube and arranged at an angle thereto, a pair of electrodes extending through each surge chamber extension and into the bottom end of the associated tube so as to be disposed in the mercury.therein, and means connecting one electrode in each surge chamber extension together, the other electrodes of both tubes opening through said extensions and being. adapted for connection in an associated circuit.

6. A switch of the kind described embodying therein a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a substantially perpendicular surge chamber extension on each tube, a pair of electrodes extending through each surge chamber extension and into the bottom end of the associated tube so as to be disposed in the mercury therein, and means connecting one electrode in each surge chamber extension together, the other electrodes of both tubes opening through said extensions and being adapted for connection in an associated circuit.

7. A switch of the kind described embodying therein a pair of tubes opositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a surge chamber extension on each tube and arranged at an angle thereto, a pair of electrodes extending through each surge chamber extension and into the bottom end of the associated tube so as to be disposed in the mercury therein, means in each tube and arranged to deflect the mercury therein into the associated surge chamber extension when said tube is tipped into that position causing the mercury to flow toward the other end of the tube, and means connecting one electrode in each surge chamber extension together, the other electrodes opening through said extensions and being adapted for connection in an associated circuit.

8. A switch of the kind described embodying therein a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a surge chamber extension on each tube and arranged at an angle thereto, a pair of electrodes extending through each surge chamber extension and into the bottom end of the associated tube so as to be disposed in the mercury therein, means secured to one electrode in each tube near said surge chamber extension and arranged to deflect the mercury in said tube into said surge chamber extension when said tube is tipped into that position causing the mercury to flow toward the other end of the tube, and means connecting one electrode in each surge chamber extension together, the other electrodes opening through said extensions and being adapted for connection in an associated circuit.

9. A switch of the kind described embodying therein a pair of tubes oppositely inclined from the perpendicular, a quantity of mercury normally disposed in the bottom end of each tube, a plurality of conductors associated with said tubes, one of said conductors having portions disposed in the mercury in both tubes, the other conductors each having a portion arranged outside of an associated tube and each having another portion arranged in the mercury in an asso- ,ciated tube so that said conductors are normally connected in series through said mercury, and a disc carried by one of said conductor portions in each tube above the mercury therein.

EDWARD D. LAWSON.

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