US3818161A - Automatic floating gravity controlled mercury safety switch with reset means - Google Patents

Abstract

A tilt switch for turning off the ignition of a tractor or other vehicle when it is tilted consisting of a first tube enclosing a mercury switch and second tube having a movable ball weight, the two tubes being mounted in a balanced configuration wherein once this combination is tilted in a selected direction, the ball weight in the one tube shifts the balance of the combination to cause and maintain an ''''off'''' switching condition.

Description

United I States Patent [191 [111 3,818,161 Richey 1 June 18, 1974 [5 AUTOMATIC FLOATING GRAVITY 2,291,236 7/1942 Kilgour ZOO/61.5 x CONTROLLED MERCURY SAFETY 3,022,392 2/1962 Clemson ZOO/61.5 3,599,745 8/1971 Hughes ZOO/61.47 X SWITCH WITH RESET MEANS 3,745,277 7/1973 Shawcross et al. ZOO/6L5 [76] Inventor: James W. Richey, RR. 1, Pisgah, 3,772,643 11/1973 Dodd et a]. 340/52 H Ala. 35765 22 Filed: Oct. 11 1972 Primary Examiner-James R, Scott [21] Appl. No.: 296,604

. ABSTRACT [52] us. (:1. zoo/61.47, ZOO/61.5, 340/52 11 A tilt Switch for mming Off the ignition of a "actor or 51 1m. 01. H01h 35/14 other Yehicle when it is Fined consisting of first tube 58 Field of Search.. 200/6l.47, 220, 224, 61.45 R, enclosmg merqlry swltch and nd tube having 14 200/6153; 340/261, 262, 52 R, 52 H, 261 movable ball welght, the two tubes being mounted in a 307/121 balanced configuration wherein once this combination is tilted in a selected direction, the ball weight in the 56] References Cited one tube shifts the balance of the combination to UNITED STATES PATENTS cause and maintain an off switching condition. 2,287,386 6/1942 McCabe 200/220 X 5 Claims, 2 Drawing Figures mm W mmNNDm SUMMARY OF THE INVENTION In accordance with the invention, two elongated tubes are mounted together, generally in line and pivotally supported as a tiltable structure at a midlongitudinal point. One of the tubes has electrical contacts at one end and mercury therein to comprise a mercury switch. The other tube has a ball weight free to move from end to end in that tube. Normally, in aswitch closed mode this structure is tilted with the mercury covering the switch contacts and the ball at one end of the other tube, to essentially bias the structure to maintain the closed switch posture. Upon tilt of the vehicle in which the structure is mounted, which shifts the orientation of the structure to a posture wherein the ball can move to the other end of its tube, it does so and the structure is reverse tilted and the mercury switch opens. The open position of the structure is controlled by a support which limits tilt to a position wherein the mercury containing tube is slightly tilted downward at the supported end and the other tube is slightly tilted upward, whereby the ball weight tends to roll back to produce a closed condition of the switch. This is impeded, however, by a reset switch control which includes a pivoted arm which in its natural resting state prevents tilt back of the structure to a closed position. When operated to reset the switch, this arm is moved out of contact with the switching structure and the structure permitted to tilt back to its normally closed mode, enabling a tractor or other vehicle to be started.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of an embodiment of the invention.

FIG. 2 is an electrical block diagram of a switching system constructed in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a tilt switching assembly employs a tiltable structure 12 upon which is mounted an elongated tubular mercury switch SW1 having a pair of contacts 14 connected outward through the glass wall 16 of tube 18 by cables 20 and 22 to terminals 24 and 26, respectively. A quantity of mercury 28 is enclosed within tube 18 and adapted to interconnect contacts 14 when mercury switch SW1 is tilted as shown in solid lines, a normally closed position for the switch. In this posture, a circuit is closed between ground, battery B1, terminal 24, switching contacts 14, terminal 26 to vehicle ignition circuit 30 and, where desired, to solenoid fuel valve 32, connected in circuit with the fuel supply to a gasoline or diesel engine. Switch SW3 is an over 2 operated normally by sounding of the buzzer L2 when switch SW3 is closed. 1

A second elongated tube 34 is positioned essentially in line with mercury switch SW1 above mercury switch SW1, tube 18 and mercury switch SW1 being attached to tiltable platform 12 by brackets 36 and 38. As will be noted, tube 34 and mercury switch SW1 are relatively inclined at a small angle so that when tiltable ride switch which is connected across mercury switch platform 12 is in the position shown in dashed lines, which is a latched off mode for the tilt switch, mercury 28 flows to end 40 of tiltable structure 12. In this same position, movable ball 42, which provides an unbalancing weight for the structure and is free to roll within tube 34, would tend to roll from the position shown in dashed lines at end 44 of tube 34 to end 46 of tube 34.

Assuming that tiltable platform 12 has been caused to move to the position illustrated in dashed lines by virtue of a tilt of the vehicle in a direction which would cause a clockwise tilt about axis 48 of the switch, ball 42 would tend to move from end 40 of tube 34 to end 46 of tube 34 and cause the balance of the tiltable platfomi 1,2 to shift back to the position shown in solid lines, which would immediately cause switching contacts 14 to close and ignition circuit 30 of a vehicle to be again energized. Since the position of tilt may not have been remedied, this is not desirable and is prevented by reset arm 50 which is pivotally mounted to a frame support 32 by shaft assembly 54. Arm 50 is biased to the position shown in solid lines by spring 56 attached between arm 50 and frame 58. The connection to frame 58 of various mounting points on the structure are schematically illustrated and would be appropriately configured to make connection to the components attached thereto. End support 60, which is shown supporting end 40 of tiltable platform 12 in an off mode of the switch, employs an upright shaft 62 which extends movably through an opening in bracket 64 attached to frame 58. Shaft 62 is vertically limited in upward travel by locking member 66, such as by a C- shaped washer in a slot in shaft 62, not shown. Spring 68 supplies a bias between bracket 64 and enlarged upper end 70 of shaft 62 to provide a spring biased support to end 40 of tiltable platform 12.

Assuming initially that switching assembly 10, mounted on a vehicle, is in the posture shown in solid lines with switching contacts 14 closed by mercury 28 enabling an ignition circuit 30 of a vehicle to be energized. Thereafter, if the switch is tilted so that switching assembly 10 tilts clockwise more than 35-40, tiltable platform 12 will be rotated clockwise, momentarily displacing upward end 51 of reset arm 50 and causing tiltable platform 12 to assume the latched position shown in dashed lines with mercury 28 moved to the right and switching contacts 14 open. This would then turn off vehicle ignition circuit 30. Alternately, or in conjunction with vehicle ignition circuit 30, solenoid fuel valve 32 would be opened by contacts 14 shutting off fuel flow to the engine of a vehicle. Battery Bl provides power through switching contacts 14 to either or both of the vehicle ignition circuit 30 and solenoid valve 32.

When it is desired to reset the switch to a closed posture, arm 50 is depressed by linkage 72 conncted to an appropriately positioned hand control, not shown. This tilts end 74 of platform 12 upward and depresses end 40 and compresses spring 68. Then arm 50 clears end 3 74 of platform 12 allowing tiltable platform 12 to be rotated counterclockwise to the solid line position by the weight of ball 42 to close switch SW]. A bolt 76 attached to frame 58 and adjusted by nut 78 provides an adjustable height stop for end 74 of tiltable platform 12. End member 80 on tiltable platform 12 provides protection for cables 20 and 22 which extend down throughholes, not shown, in tiltable platform 12 to terminals 24 and 26. An axle assembly 82 attached to frame 58 provides a freely rotating mounting support for tiltable platform l2.

What is claimed is:

l. A tilt switching system comprising:

en elongated tiltable structure having first and second ends and comprising:

a first elongated tube having first and second closed ends, a pair of electrical contacts within said first end, and a quantity of mercury within said tube adapted to electrically interconnect said contacts when said first end of said first elongated tube is tilted downward,

a second elobgated tube having first and second ends positioned generally in line with and adjacent like labelled ends of said first elongated tube and a ball weight within said second elongated tube sized to enable free movement from end to end of said second elongated tube, and

mounting means including tilt means for pivotally supporting said elongated structure about an axis perpendicular to the longitudinal dimension of said structure, said axis lying within a plane generally normal to the longitudinal dimension of said structure, which plane is intermediate between the ends of said tubes and wherein said tubes are slightly, relatively inclined, with maximum separation at said second adjacent ends of said tubes,

end support means for supporting said second end of said tiltable structure when said switch is operated 4 ofP and wherein said second end of said first tube is tilted downward slightly and said second end of said second tube is tilted upward slightly, whereby said ball is inclined to roll toward said firstend of said second tube and said mercury is inclined to remain at said second end of said first tube, and reset means adapted to engage said first end of said tiltable structure for normally holding said switch and said tiltable structure in an off position once said tiltable structure is caused to assume an on I position with said mercury at said second end of said first tube, and upon operation, to release said tiltable structure and allow said tiltable'structure to again tilt to an on position with said mercury at said first end of said first tube.

2. A tilt switching system 'as set forth in claim 1 wherein said end support means comprises a spring loaded support, compressable-upon operation of said reset means; and

said reset means comprises an arm pivotally mounted and adapted to engage a lower edge of said first end of said tiltable structure, and move that end upward slightly and then release it, whereby the 7 weight of said ball on said first end of said tiltable structure causes said first end of said tiltable structure to be depressed, and said mercury to move to 4. A tilt switching system as set forth in claim 2 further comprising a solenoid fuel valve and battery electrically connected in series with'said contacts.

5. A tilt switching system as set forth in claim 3 further comprising a switch and an electrically operated alarm connected in series across said contacts.

Claims (5)

1. A tilt switching system comprising: en elongated tiltable structure having first and second ends and comprising: a first elongated tube having first and second closed ends, a pair of electrical contacts within said first end, and a quantity of mercury within said tube adapted to electrically interconnect said contacts when said first end of said first elongated tube is tilted downward, a second elobgated tube having first and second ends positioned generally in line with and adjacent like labelled ends of said first elongated tube and a ball weight within said second elongated tube sized to enable free movement from end to end of said second elongated tube, and mounting means including tilt means for pivotally supporting said elongated structure about an axis perpendicular to the longitudinal dimension of said structure, said axis lying within a plane generally normal to the longitudinal dimension of said structure, which plane is intermediate between the ends of said tubes and wherein said tubes are slightly, relatively inclined, with maximum separation at said second adjacent ends of said tubes, end support means for supporting said second end of said tiltable structure when said switch is operated ''''off'''' and wherein said second end of said first tube is tilted downward slightly and said second end of said second tube is tilted upward slightly, whereby said ball is inclined to roll toward said first end of said second tube and said mercury is inclined to remain at said second end of said first tube, and reset means adapted to engage said first end of said tiltable structure for normally holding said switch and said tiltable structure in an ''''off'''' position once said tiltable structure is caused to assume an ''''off'''' position with said mercury at said second end of said first tube, and upon operation, to release said tiltable structure and allow said tiltable structure to again tilt to an ''''on'''' position with said mercury at said first end of said first tube.

2. A tilt switching system as set forth in claim 1 wherein said end support means comprises a spring loaded support, compressable upon operation of said reset means; and said reset means comprises an arm pivotally mounted and adapted to engage a lower edge of said first end of said tiltable structure, and move that end upward slightly and then release it, whereby the weight of said ball on said first end of said tiltable structure causes said first end of said tiltable structure to be depressed, and said mercury to move to said first end of said first elongated tube and close said contacts.

3. A tilt switching system as set forth in claim 2 further comprising a vehicle ignition circuit and battery connected in series with said contacts.

4. A tilt switching system as set forth in claim 2 further comprising a solenoid fuel valve and battery electrically connected in series with said contacts.

5. A tilt switching system as set forth in claim 3 further comprising a switch and an electrically operated alarm connected in series across said contacts.

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