Lifting mechanism
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Solution Overview
Problem
Existing lifting mechanisms in healthcare beds are costly, bulky, and pose a risk of entrapment due to complex moving parts, which restrict access and increase the risk of injury, especially for vulnerable patients.
Innovation Solution
A compact lifting assembly featuring a telescopic post assembly with a pulley mechanism where the movement of the outer tubular member relative to the inner member is faster, minimizing exposed parts and using tensioning means to manage cable tension, with wheels housed to reduce entrapment risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex lifting mechanism with multiple components is used, then the lifting function is achieved, but the manufacturing cost increases and the device becomes bulky
Solution Approach 1:
The patent employs a telescopic post assembly where multiple tubular members are nested within each other (inner tubular member within intermediate tubular member within outer tubular member). This nesting arrangement achieves the lifting function through a compact structure, eliminating the need for separate bulky components while maintaining reliability. The nested design directly reduces device complexity and manufacturing cost by integrating multiple functions into a single compact assembly.
2Reliability
If a bulky lifting system is used, then the lifting function is achieved, but the space occupied at the end of the bed increases and access to the patient is restricted
Solution Approach 1:
The telescopic post assembly with nested tubular members significantly reduces the volume occupied by the lifting mechanism. When retracted, the nested structure occupies minimal space at the end of the bed, while still providing the full lifting function. This resolves the contradiction by achieving reliable lifting without the bulky form factor that would restrict patient access.
Solution Approach 2:
The lifting mechanism uses a dynamic telescopic structure where the tubular members extend and retract as needed. This dynamic design allows the system to occupy minimal space when not in use, while providing full lifting capability when required. The pulley mechanism also enables dynamic cable tensioning to accommodate the changing geometry during extension and retraction.
3Reliability
If moving parts are exposed in the lifting mechanism, then the lifting function is achieved, but the risk of entrapment increases
Solution Approach 1:
The patent extracts the pulley mechanism and cable system from the external environment and houses them within the telescopic post assembly. The pulleys are mounted inside the tubular members, and the cables are contained within the structure, removing exposed moving parts that could cause entrapment. This maintains the lifting function while eliminating the harmful entrapment risk associated with exposed mechanisms.
4Productivity
If the movement speed of the outer tubular member is increased relative to the inner member, then the lifting efficiency is improved, but the cable tension requirements increase
Solution Approach 1:
The patent introduces a pulley mechanism as an intermediary between the actuator and the outer tubular member. The pulleys redirect and distribute the cable forces, allowing the system to achieve higher lifting speeds without proportionally increasing the cable tension requirements. The pulley system acts as a mechanical intermediary that optimizes the force distribution and enables faster lifting while managing tension within acceptable limits.
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 provides a cost-effective, space-efficient lifting mechanism that reduces the risk of injury by allowing safe and efficient height adjustment of the bed while minimizing exposure of moving parts, enhancing patient safety and accessibility.
Implementation Method 1
a pulley mechanism comprising: a first wheel rotatably mounted at a first end of the second tubular member; a second wheel rotatably mounted at a second end of the second tubular member; a first length of cable having a first end fixed to the first tubular member and a second end fixed to the third tubular member, the first length of cable being engaged with the first wheel; and a second length of cable having a first end fixed to the first tubular member and a second end fixed to the third tubular member, the second length of cable being engaged with the second wheel
Data Source
Figure 1~2
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AI summary
This invention relates to lifting mechanisms. In particular this invention relates to lifting mechanisms for use in healthcare equipment such as beds. A lifting assembly comprises a telescopic post assembly including a first tubular member, a second tubular member slidingly engaged with the first tubular member, and a third tubular member slidingly engaged with the second tubular member, the first, second and third tubular members being coaxial; an actuator configured to move the second tubular member axially with respect to the first tubular member; and a pulley mechanism comprising a first wheel rotatably mounted at a first end of the second tubular member; a second wheel rotatably mounted at a second end of the second tubular member; a first length of cable having a first end fixed to the first tubular member and a second end fixed to the third tubular member, the first length of cable being engaged with the first wheel; and a second length of cable having a first end fixed to the first tubular member and a second end fixed to the third tubular member, the second length of cable being engaged with the second wheel, wherein the pulley mechanism is arranged such that the movement of the third tubular member relative to the first tubular member is at a greater speed than the movement of the second tubular member relative to the first tubular member.