Spare Tire Mount with Worm Screw Lift Mechanism
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Solution Overview
Problem
Off-road motor vehicles face challenges with heavy spare tires and wheels, making it difficult to open the rear door, mount different-sized spare tires, and safely remove and install them due to weight and physical strain.
Innovation Solution
A spare tire mounting system with a first and second support frame that rotate about vertical and horizontal axes, using a wire rope and worm screw mechanism to lift and lower the tire, allowing for independent movement from the rear door and accommodating various sizes, with an adjustable swivel linkage for different rotational axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the spare tire and wheel are mounted on the rear door, then the spare tire is accessible, but the weight on the door increases making it difficult to open
Solution Approach 1:
The spare tire and wheel assembly is extracted from the rear door and relocated to a separate mounting system on the rear bumper. This separation removes the heavy load from the door, allowing it to open easily while the spare tire remains accessible through the new mounting location.
Solution Approach 2:
A connecting link with a rotatable joint serves as an intermediary between the rear door and the spare tire mounting system. This linkage allows the door and mounting system to move independently, with the rotatable joint accommodating the different rotational axes of the door hinge and the mounting system, thereby eliminating the weight problem while maintaining connectivity.
2Adaptability or versatility
If larger wheels and tires are used, then the vehicle performance is improved, but it becomes difficult or impossible to mount a matching spare tire on the vehicle door
Solution Approach 1:
The mounting system incorporates adjustable components including an adjustable-length connecting link and a rotatable joint that can accommodate different rotational axes. This dynamic adjustability allows the system to adapt to various wheel and tire sizes, making it versatile for different vehicle configurations while maintaining ease of mounting operations.
3Ease of operation
If the spare tire is mounted on an elevated platform, then it is accessible, but users have difficulty physically removing and setting it on the ground due to weight
Solution Approach 1:
A wire rope connected to a reel mounted on the first support frame serves as a counterweight mechanism. The wire rope is wound around the reel to support the weight of the spare tire, reducing the effort required by users to lift and lower the heavy tire assembly. The reel can be rotated manually or with mechanical assistance to control the lowering and lifting operations.
4Ease of operation
If the spare tire is mounted on an elevated platform, then it is accessible, but dropping it may cause injury or damage
Solution Approach 1:
The wire rope connected to the reel provides a controlled lowering mechanism that prevents free-falling of the spare tire. By winding the wire rope around the reel, the system ensures the tire descends in a controlled manner, eliminating the risk of sudden drops that could cause injury or damage to the vehicle or surrounding property.
5Stability of the object's composition
If the spare tire mounting mechanism is linked to the rear door, then they rotate together, but the different rotational axes cause movement conflicts
Solution Approach 1:
A rotatable joint serves as an intermediary connection between the rear door and the first support frame. This joint allows the two components to rotate about different vertical axes independently, accommodating the geometric constraints of both the door hinge and the mounting system while maintaining a stable connected structure. The rotatable joint absorbs the rotational differences without creating mechanical conflicts.
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
Enables easier access and safer handling of spare tires by reducing the weight on the rear door, allowing for the mounting of various sizes, and facilitating the removal and installation of spare tires without straining the user, while preventing damage or injury.
Implementation Method 1
A wire rope winds around a reel on the first frame with the rope connected to the second frame to raise and lower the second frame and tire
Implementation Method 2
The reel is rotated by a worm screw and worm wheel
Implementation Method 3
Both frames rotate about a vertical joint at the rear bumper so the frames rotate toward and away from the vehicle
Data Source
AI summary
A spare tire mount for the rear of a motor vehicle has a first outer support frame with a second, inner support frame nested inside and releasably connected to the first frame. Both frames extend laterally across the back of the vehicle and extend upward at an angle. Both frames rotate about a vertical joint at the rear bumper so the frames rotate toward and away from the vehicle. The second frame holds the spare tire and rotates about a horizontal axis. A wire rope winds around a reel on the first frame with the rope connected to the second frame to raise and lower the second frame and tire as they rotate about the first horizontal axis—toward and away from the first frame and ground. The reel is rotated by a worm screw and worm wheel.