Hoist Safety Lock via Eccentric Cam and Spring Release
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Solution Overview
Problem
Conventional ceiling-mounted hoists for physically impaired or handicapped persons cannot be manually moved in case of a power outage or battery depletion, as they rely on electric power for operation, posing a safety concern when power is interrupted.
Innovation Solution
A mechanical safety locking and releasing system is integrated into the hoist trolley, utilizing a spring mechanism and eccentric cam to allow manual movement by releasing the drive wheels from the rail, enabling operation independent of power supply, with a handle or motor actuation for control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hoist uses a motorized drive system with spring pressure against the rail, then the hoist can move along the rails when powered, but it becomes impossible to move the hoist manually when electric power is cut off
Solution Approach 1:
The bracket is designed to be pivotally connected to the cart via a hinge, allowing it to rotate between a locked position (where drive wheels contact the rail) and an unlocked position (where drive wheels are released from the rail). This dynamic configuration enables the system to switch between motorized operation and manual movability based on operational needs.
Solution Approach 2:
An eccentric cam mounted on a rotatable shaft serves as an intermediary mechanism between the operator and the drive wheel contact pressure. By rotating the shaft, the eccentric cam modulates the spring force applied to the drive wheels, enabling controlled release or engagement of the wheels with the rail surface without directly overcoming the spring force.
2Reliability
If a spring mechanism is used to press drive wheels against the rail for motorized movement, then the hoist achieves reliable motorized operation, but it cannot be moved manually when power is lost
Solution Approach 1:
The drive system is designed to serve dual functions: motorized propulsion when power is available and manual movability when power is lost. The same drive wheels and spring mechanism that enable reliable motorized operation also facilitate manual movement when the bracket is rotated to release the drive wheels from the rail, eliminating the need for separate systems for different operational modes.
Solution Approach 2:
The system dynamically adjusts the contact pressure between drive wheels and rail through bracket rotation. During normal operation, the spring maintains firm contact for reliable motorized movement. During power outages, the bracket can be rotated to reduce contact pressure, allowing the hoist to be manually moved along the rail.
3Stability of the object's composition
If the drive wheels are constantly pressed against the rail by a spring, then the hoist maintains stable position and can be motorized, but manual movement becomes impossible without power
Solution Approach 1:
The bracket's pivotal connection allows it to rotate between a stable locked position (maintaining drive wheel contact with the rail for position stability) and an unlocked position (releasing drive wheels for manual repositioning). This dynamic transition enables the system to switch between stability and manual movability as needed.
Solution Approach 2:
The eccentric cam on the rotatable shaft acts as an intermediary that controls the spring force transmission to the drive wheels. By rotating the shaft, the operator can modulate the contact pressure, enabling smooth transition from stable motorized operation to manual repositioning without sudden changes in force.
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 system allows reliable and safe manual movement of the hoist along the rail, ensuring continued functionality during power outages or battery depletion, providing a cost-effective and reliable solution for handling physically impaired individuals.
Implementation Method 1
a spring member having a first end connected to the cart and second end connected to the bracket provided for pressing the one or more drive wheels against a running surface on the rail
Implementation Method 2
A shaft with an eccentric cam is rotatably mounted in the bracket, where said eccentric cam upon rotation of the shaft acts against a surface on the cart for rotation of the bracket in relation to the cart in the hinge whereby said one or more drive wheels are released from contact with the running surface
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
A hoist (1) where said hoist comprises a trolley (3) with one or more wheels arranged to run along a first running surface (2a) of a rail (2). Said trolley (3) comprises one or more drive wheels (14) and one or more suspension wheels (11). The one or more suspension wheels (11) are rotatably fixed on a cart (7). One or more drive wheels (14) are rotatably fixed to a bracket (8) and said bracket (8) is pivotably connected via a hinge (16) to the cart (7). Said trolley (3) comprises a spring member (21) having a first end connected to the cart (7) and second end connected to the bracket (8). The spring member (21) is provided for pressing the one or more drive wheels (14) against a running surface (2b) on the rail (2). A shaft (22) with an eccentric cam (23) is rotatably mounted in the bracket (8). The eccentric cam (23) acts upon rotation against an edge surface (27) on the cart (7) for rotation of the bracket (8) in relation to the cart in the hinge (16). Hereby said one or more drive wheels (14) are released from contact with the running surface (2b), whereby the one or more suspension wheels (11) are able to rotate freely along the rail (2), e.g. by moving the hoist manually in the rail (2). This provides a safety locking and releasing system for the hoist in relation to the rail (2).