ANTI-FISHTAIL DEVICE FOR TRAILERS

• US 3,810,521 A
• Filed: 08/18/1970
• Issued: 05/14/1974
• Est. Priority Date: 08/18/1970
• Status: Expired due to Term

• Current Assignee: Albert E. Sparr
• Original Assignee: Albert E. Sparr
• Inventors: Sparr, Albert E.
• Primary Examiner(s): Betts, Kenneth H.
• Application Number:
  US05/064,684
• Time in Patent Office: 1,365 Days
• Field of Search: 280/432,446 180/103 188/112,158,3 303/7
• US Class Current: 188/112.00A
• CPC Class Codes: B60D 1/06 Ball-and-socket hitches , e.g. constructional details, auxiliary devices, their arrangement on the vehicle
• CPC Class Codes: B60T 7/20 specially for trailers, e.g. in case of uncoupling of or overrunning by trailer inertia-actuated overrun brakes B60T13/08

Abstract

The specification discloses an anti-fishtail device for trailers. The device operates on the fact that application of the trailer brakes only will stop the fishtail of a trailer once it starts. An electric pickup is supported on the trailer coupler which is in turn secured to the frame of the automobile. It is actuated by the relative angular movement between the trailer and the towing vehicle. The apex of this angle is the center of the ball coupler on the hitch. This relative movement causes the pickup to send a signal through suitable circuitry to an amplifier which is connected to the electrical brakes of the trailer. The system, in effect, measures the rate of change of angle between the trailer and the vehicle and provides corrective action proportional to the disturbance.

Claims

1. An anti-fishtail device for trailers having brakes actuated by a suitable medium with suitable interface devices comprising a pickup member having a movable actuating member, means for connecting said pickup and said actuator to a towing vehicle and to a trailer whereby said actuating member is moved when said towing vehicle turns relative to said trailer, and connecting means connecting said pickup to said trailer brakes whereby said pickuP is actuated and sends a signal to said trailer brakes through said connecting means when said trailer sways relative to said towing vehicle at a predetermined rate, and sends no signal to said trailer brakes when said trailer sways relative to said towing vehicle at less than said predetermined rate.

2. The device recited in claim 1 wherein said medium is electricity.

3. The device recited in claim 1 wherein said means connecting said pickup to said brakes comprises an electronic device, said pickup passes signals to said electronic device when the rate of angle change between said trailer and said vehicle exceeds a predetermined rate.

4. An anti-fishtail device for trailers comprising, a transducer adapted to be supported on a trailer and towing vehicle combination, said transducer having means to produce an electric signal of a magnitude and frequency in proportion to the rate of change of the angle between said trailer and said towing vehicle, and means on said trailer brakes to receive said signal and to apply said trailer brakes proportionally to the signal when said signal reaches a predetermined magnitude, and to automatically release said brakes when need for this corrective action is no longer needed.

5. An anti-fishtail device comprising a transducer, means for supporting said transducer on a towing vehicle, means connecting the actuating device of said transducer to said trailer whereby said transducer produces an output proportional to the relative magnitude and velocity of change of angle between said trailer to said towing vehicle, means connecting the output of said transducer to the actuating means on the trailer brakes whereby said brakes are applied and said fishtailing is stopped, after which said brakes are automatically released, said means supporting said transducer comprising a support plate having means for attaching it to a trailer hitch, a movable plate, means supporting said movable plate on said hitch, said transducer supported on said movable plate and means connecting said movable plate to said trailer whereby said movable plate is moved by said trailer in proportion to the magnitude and frequency of movement of said trailer relative to said towing vehicle, and means connected to and actuated by said signal to apply said trailer brakes.

6. An anti-fishtail device recited in claim 5 comprising a mechanical linkage sensitive to small angles between trailer and towing car for fishtail detection and which is insensitive to 45* angles between trailer and towing car while parking or moving said vehicles at low speeds.

7. The anti-fishtail device recited in claim 6 wherein said transducer is supported on said trailer by means of a plate having a trailer hitch ball member extending through it, a pickup member supported on said plate, and means connectable to said trailer whereby the said pickup is actuated when said trailer sways at a predetermined rate.