Hospital Bed Frame Chassis Layout for Low Entry Height
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Solution Overview
Problem
Existing bed frames with scissor mechanisms face a trade-off between achieving a low entry height and maintaining smooth operation, as smaller wheel discs compromise comfort and the integration of a parking brake, while larger discs hinder maneuverability and standardization.
Innovation Solution
The design incorporates a chassis with downward-pointing connecting extensions and a support device, allowing the scissor mechanism to be offset below the wheel discs, enabling the use of larger discs for smooth operation and a low entry height, and includes a support device to maintain stability without a longitudinal brace.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If smaller wheel discs are used to achieve lower entry height, then the entry height is reduced, but the operation smoothness and comfort deteriorate
Solution Approach 1:
The patent relocates the scissor mechanism from a horizontal arrangement (along the bed frame) to a vertical arrangement (below the crossbeam). This dimensional change allows the mechanism to occupy vertical space rather than horizontal space, enabling lower entry height while maintaining sufficient wheel disc diameter for smooth operation. The scissor mechanism is positioned in the vertical dimension below the crossbeam, freeing up horizontal space and allowing larger wheel discs to be used without increasing the overall footprint.
2Ease of operation
If larger wheel discs are used to improve operation smoothness, then the operation comfort is improved, but the entry height increases
Solution Approach 1:
The scissor mechanism is repositioned to the vertical dimension below the crossbeam, allowing larger wheel discs to be used in the horizontal plane without increasing entry height. The mechanism's vertical placement creates separation between the wheel disc plane and the mechanism plane, enabling independent optimization of both wheel size and entry height.
3Length of moving object
If the scissor mechanism is placed below the bed frame, then the bed frame length is reduced and maneuverability is improved, but the entry height increases
Solution Approach 1:
The scissor mechanism is positioned in the vertical dimension below the crossbeam rather than extending horizontally along the bed frame. This vertical placement maintains the compact horizontal footprint for easy maneuverability while simultaneously reducing entry height by utilizing the vertical space beneath the crossbeam.
Solution Approach 2:
A connecting extension with a bearing eye is introduced as an intermediary component between the crossbeam and the scissor mechanism. This connecting element allows the scissor mechanism to be offset below the crossbeam while maintaining proper mechanical connection and rotation axis alignment, enabling the mechanism to be positioned lower without compromising structural integrity.
4Length of stationary object
If smaller wheel discs are used, then the entry height is reduced, but the ability to integrate a parking brake is lost
Solution Approach 1:
The scissor mechanism is repositioned to the vertical dimension below the crossbeam, creating sufficient space on the wheel disc to accommodate a parking brake. The vertical placement of the mechanism frees up horizontal space on the wheel disc, allowing integration of braking components without increasing entry height.
Data Source
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AI summary
The invention relates to a bed frame for a hospital and/or nursing bed, comprising a scissor mechanism (4) for the height adjustment of a bed frame (5) supported by the scissor mechanism (4) and comprising a first and a second undercarriage (1, 2) which is in each case arranged on the scissor mechanism (4), wherein an undercarriage (1, 2) comprises a crosspiece (7) having bearing bushes (8, 9) at the end faces for the respective reception of a wheel unit (10, 11) with a wheel disc (12, 13; 14, 15) that is rotatably mounted about an axis of rotation (16, 17), characterized in that an undercarriage (1, 2) has a connection extension (18, 19) which points downwards starting from the crosspiece (7), is arranged at one end face on the crosspiece (7) and has at the other end face a bearing lug (20, 21) for the rotationally pivotably arrangement on the scissor mechanism (4), wherein the axis of rotation (22, 23) defined by the bearing lug (20, 21) extends in the direction of height (6) of the undercarriage (1, 2) below the axis of rotation (16, 17) of a wheel disc (12, 13; 14, 15).