Dental Chair Trunnion Limit Switch for Obstruction Stop Control
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Solution Overview
Problem
Conventional dental chairs often cause discomfort and pain when the reclining seatback encounters an obstruction, such as a person's legs, due to its heavy design and inability to stop movement effectively.
Innovation Solution
The integration of cylinders, trunnions, and limit switches in dental chairs allows for controlled movement of the seatback, detecting obstructions and automatically stopping downward movement to prevent further discomfort or damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the seatback is designed to be heavy for supporting a patient, then the load-bearing capacity is improved, but the risk of causing pain or discomfort to obstructions increases
Solution Approach 1:
The patent implements a limit switch that provides feedback control for the seatback movement. When the seatback reaches a predetermined position or encounters an obstruction, the limit switch detects this condition and sends a signal to stop the motor-driven movement, preventing further movement that would cause pain or discomfort to any obstruction (such as a dental hygienist's legs). This feedback mechanism allows the seatback to maintain its heavy design for patient support while automatically preventing harmful over-movement.
2Manufacturing precision
If the seatback continues to recline to complete the orientation change, then the positioning accuracy is improved, but the harmful effects on obstructions worsen
Solution Approach 1:
The patent applies preliminary action by positioning the limit switch in advance along the movement path of the seatback. The limit switch is preset to activate at a specific position before the seatback would potentially contact an obstruction or reach the end of its safe travel range. This preliminary positioning ensures that the motor-driven seatback stops at the correct position, achieving accurate positioning while preventing harmful effects on obstructions.
3Device complexity
If no safety mechanism is installed to reduce device complexity, then the device complexity is reduced, but the reliability of preventing harmful effects worsens
Solution Approach 1:
The patent replaces complex mechanical safety mechanisms with an electrical control system. Instead of using mechanical stops, springs, or cam-based limit switches that require mechanical intervention, the system uses a motor-driven seatback with an electrically-operated limit switch and control circuitry. This substitution reduces mechanical complexity while improving reliability, as the electrical system can precisely control and stop the seatback movement at predetermined positions without requiring complex mechanical safety devices.
Data Source
AI summary
Dental devices with cylinders, trunnions, and limit switches, and a method are provided. The dental devices include a cylinder and a trunnion having a cavity and an outer surface. A portion of the cylinder is slidably mounted within the cavity of the trunnion, and a portion of the cylinder protrudes out of the trunnion. The limit switch is coupled to the outer surface of the trunnion, with the limit switch is operable to contact the cylinder. Separation of the limit switch and the cylinder causes actuation of the limit switch, and the actuation of the limit switch inhibits a downward movement of the device. Alternatively, the limit switch may be coupled to the portion of the cylinder that protrudes out of the trunnion, with the limit switch operable to contact the trunnion. As such, separation of the limit switch and the trunnion causes actuation of the limit switch.