Trailer Coupling Linkage With Watt Parallelogram for Rollover Resistance
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Solution Overview
Problem
Existing trailer attachment systems either allow rotational movements that prevent using the towing vehicle's low center of gravity to counter trailer reversal or require complex braking systems to prevent rollover during turns.
Innovation Solution
A coupling plate with a pivot extending perpendicular to the plate, connected to a trailer chassis via an articulated structure defining a Watt parallelogram, allowing longitudinal movement and prohibiting rotational movements around the longitudinal axis, thus enabling inertial braking while preventing trailer rollover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a ball joint drawbar assembly is used to connect the trailer to the towing vehicle, then the connection allows rotational movement and is simple to manufacture, but the low center of gravity of the towing vehicle cannot be used to prevent the trailer from rolling over when cornering
Solution Approach 1:
The connection system is segmented into two independent rotational degrees of freedom: rotation around the vertical axis (for cornering) and rotation around the transverse axis (for braking). This segmentation allows the towing vehicle's low center of gravity to effectively counter trailer rollover during cornering while still permitting necessary movements
Solution Approach 2:
The connection system dynamically adapts its behavior by allowing rotation around the vertical axis when cornering forces are applied, while the low center of gravity of the towing vehicle provides a counteracting moment to prevent rollover. The system maintains stability through dynamic balance rather than rigid constraint
2Stability of the object's composition
If a plate-fifth wheel connection is used to prevent trailer rollover during cornering, then rotational movements around the longitudinal direction are prohibited, but complex pneumatic braking systems are required
Solution Approach 1:
The complex pneumatic braking system is extracted and replaced by a simple inertial brake mechanism. The inertial brake uses the natural longitudinal movement of the drawbar relative to the trailer during braking to activate the braking system, eliminating the need for complex pneumatic controls while maintaining effective braking capability
Solution Approach 2:
The braking system is designed to be self-actuating through inertial forces. During braking, the drawbar moves longitudinally relative to the trailer, and this movement automatically activates the inertial brake without requiring external pneumatic control systems. The system uses the braking force itself to trigger the brake activation
3Stability of the object's composition
If a connection system prohibits any longitudinal translational movement to prevent rollover, then stability is improved, but the ability to activate inertial braking is lost
Solution Approach 1:
The connection system applies different movement constraints to different directions: it allows longitudinal translational movement (necessary for inertial braking) while prohibiting rotational movements around the longitudinal axis (necessary for rollover prevention). This directional differentiation of constraints enables both functionalities to coexist
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for efficient inertial braking and resistance to trailer rollover during turns, while being simple to produce and assemble, with low friction and no play, ensuring a rigid connection.
Implementation Method 1
the articulated connecting structure comprising two links, each link being provided with a pair of articulations with axes of rotation perpendicular to the plate: a first articulation mounted on the plate and a second articulation intended to be mounted on the trailer chassis, the articulated connecting structure defining a Watt parallelogram allowing movement of the pivot along a substantially rectilinear and longitudinal trajectory
Implementation Method 2
at least one of the first and second joints of each connecting rod may be a rolling joint, for example a ball or needle bearing. This makes it possible to reduce and/or eliminate any risk of rotation of the plate around a longitudinal axis of the chassis
Implementation Method 3
The other joints may then be elastic joints, however, in a preferred embodiment, the two joints of each connecting rod are rolling joints. The attachment device then has the advantage of being play-free, very low friction and very rigid in maintaining longitudinal rotation
Data Source
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AI summary
The invention relates to a coupling device (10) for a trailer to a towing vehicle, comprising a coupling plate (11) equipped with a pivot extending perpendicularly to the plate and intended to cooperate in rotation about an axis (13) with a coupling device of the towing vehicle. The coupling device includes an articulated linkage structure (14) for connecting the plate (11) to a trailer chassis and comprising two connecting rods (15, 16). Each connecting rod (15, 16) is provided with a pair of joints (151, 152; 161, 162) with axes of rotation perpendicular to the plate: a first joint (151, 161) mounted on the plate (11) and a second joint (152, 162) intended to be mounted on the chassis.The articulated link structure (14) defines a Watt parallelogram allowing the pivot to move along a substantially straight and longitudinal trajectory relative to the chassis when the attachment device (10) is mounted on the latter.