Patient Chair Headrest Adjustment With Compact Threaded Drive
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Solution Overview
Problem
Existing patient chair mechanisms, particularly in dental care, require manual and time-consuming adjustments for headrest and pillow positioning, leading to ergonomic challenges and potential structural instability under load, with existing motorized solutions being bulky and prone to internal forces that cause the mechanism to yield, posing safety risks.
Innovation Solution
A compact, motorized adjustment mechanism using articulated shafts with high-pitched and low-pitched threads, driven by a cogged belt system, allowing precise and powerful position control of the headrest and pillow, enabling a thin design that reduces strain on caregivers and prevents structural collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual adjustment mechanism is used, then device complexity is reduced, but ease of operation deteriorates due to heavy components requiring manual force
Solution Approach 1:
The patent replaces the manual mechanical adjustment system with an automated motorized system. The motorized adjustment mechanism automatically positions the headrest and pillow without requiring manual force, thereby improving ease of operation while managing device complexity through automated control.
2Ease of operation
If powered adjustment mechanism is used, then ease of operation is improved, but device complexity increases due to big size of machinery and power transmission elements
Solution Approach 1:
The patent changes the pitch parameter of the screw mechanism to a high pitch, which allows the use of a compact motor with sufficient torque. This parameter change enables the power transmission elements to be small in size, thereby improving ease of operation through automation while minimizing the increase in device complexity.
3Power
If high torque is required for adjustment, then adjustment power is improved, but device complexity increases due to big power transmission elements
Solution Approach 1:
The patent employs a high-pitch screw mechanism which changes the mechanical parameter of the thread pitch. This high pitch reduces the mechanical advantage required, allowing a compact motor to generate sufficient torque without requiring large power transmission elements, thus achieving high adjustment power with minimal device complexity.
Solution Approach 2:
The patent utilizes the axial dimension of the high-pitch screw to achieve torque multiplication. By changing from a traditional low-pitch screw to a high-pitch screw, the system achieves the required torque through the axial movement dimension rather than through large radial power transmission components, reducing overall mechanism size.
4Strength
If thick head rest is used, then structural strength is improved, but ease of operation deteriorates due to straining care work
Solution Approach 1:
The patent changes the pitch parameter of the screw mechanism to high pitch, which allows the headrest structure to be made thinner while maintaining sufficient structural strength. The high-pitch screw provides adequate torque and mechanical advantage in a compact form, enabling the headrest thickness to be reduced to an ergonomically acceptable level without compromising strength.
5Adaptability or versatility
If manual adjustment is performed for each patient, then adaptability is improved, but loss of time increases due to multiple adjustment stages
Solution Approach 1:
The patent replaces the manual multi-stage adjustment process with an automated motorized system. The motorized mechanism can quickly and precisely position the headrest and pillow without requiring the operator to manually open locks, adjust positions, and relock components. This automation maintains adaptability for patient-specific adjustments while significantly reducing the time required for each adjustment cycle.
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 reliable, precise, and ergonomic adjustment system that minimizes internal forces, allows for a long motion range in a small space, and prevents structural collapse, ensuring safe and efficient operation even under exceptional loads.
Implementation Method 1
cogged belt system
Implementation Method 2
articulated shafts with high-pitched and low-pitched threads
Data Source
AI summary
The object of the invention is a method and an apparatus for adjusting mutual position of two structural elements of a patient chair, like the back rest and the head rest, articulated with each other, in which method the mutual position of the two structural elements (3, 4, 5) connected with each other by articulation is adjusted by a drive device (13). With the help of the drive device (13) it is possible to produce, for example, an essentially high rotational motion that can be converted to a linear motion with the help of a thread. The linear motion is converted to an essentially slow rotational motion with the help of a thread element (9) functionally connected to an articulated shaft (6, 7) belonging to the position adjustment mechanism.