Palmar Strap Assembly for Prosthetic Backplate Stability
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Solution Overview
Problem
Existing partial hand prostheses suffer from issues such as backplate bridging and migration, discomfort, and difficulty in secure attachment, leading to impaired functionality and user experience.
Innovation Solution
The integration of an attachable palmar strap assembly with anchor points on the backplate, allowing for secure attachment without modifying the backplate design, thereby preventing bridging and enhancing human-prosthetic interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing partial hand prostheses are used without a palmar strap, then the device structure remains simple, but backplate bridging and migration occur leading to discomfort and functional impairment
Solution Approach 1:
The palmar strap assembly is divided into separate modular components including the palmar strap, anchor points, and attachment mechanism. This segmentation allows the strap system to be independently designed and attached to the backplate, preventing bridging and migration while maintaining overall device simplicity through modular assembly.
Solution Approach 2:
The palmar strap assembly acts as an intermediary element between the user's hand and the prosthetic device. By introducing this intermediate strap system with anchor points, the design prevents direct contact and potential bridging between the backplate and hand, while providing stable attachment and comfort through the strap mechanism.
2Reliability
If a traditional palmar strap is added to prevent bridging, then backplate stability improves, but the strap interferes with the distal skin crease of the palm causing discomfort
Solution Approach 1:
The anchor points are strategically positioned on the backplate at locations that correspond to anatomical landmarks away from the distal skin crease. This local optimization ensures that the strap attaches at points that provide stability without interfering with sensitive skin areas, addressing the specific anatomical constraint.
Solution Approach 2:
The anchor points are positioned in the radial and ulnar dimensions on the backplate, distributing the attachment points across different spatial dimensions. This dimensional distribution allows the strap to achieve stability while routing away from the problematic distal skin crease area, reducing discomfort.
3Strength
If fasteners are placed directly on the skin for strap attachment, then secure connection is achieved, but discomfort and skin irritation occur
Solution Approach 1:
The palmar strap serves as an intermediary element that distributes attachment forces across a larger area of the hand rather than concentrating fasteners directly on the skin. The strap material and anchor point design act as a mediator between the mechanical attachment system and the skin, reducing pressure points and discomfort while maintaining secure connection.
Solution Approach 2:
The palmar strap is designed as a flexible textile or soft material that conforms to the hand's anatomy. This flexible strap distributes attachment forces evenly across the skin surface, avoiding concentrated pressure from rigid fasteners and preventing skin irritation while maintaining secure attachment through the anchor points.
4Adaptability or versatility
If the palmar strap assembly is made attachable rather than integrated, then device customization and comfort improve, but connection reliability may be compromised
Solution Approach 1:
The anchor points are pre-integrated into the backplate during manufacturing, while the palmar strap is designed for attachable connection. This preliminary integration of the attachment mechanism ensures that when the strap is connected, it forms a reliable and stable connection. The pre-positioned anchor points eliminate the need for additional drilling or modification, ensuring connection reliability while maintaining adaptability.
Solution Approach 2:
The attachable palmar strap assembly introduces dynamic adjustability to the system, allowing users to modify or remove the strap as needed. The connection mechanism is designed to provide secure attachment when engaged, while allowing easy detachment and reattachment. This dynamic design maintains reliability during use while providing customization flexibility.
Data Source
AI summary
A prosthetic finger assembly includes one or more integrated attachment points for a palmar strap to prevent a backplate bridging and migration. The palmar strap is integrally fixed to a first anchor of a radial metacarpophalangeal pivot, which is configured to connect to the hand of a user, and removably attach to a second anchor of an ulnar metacarpophalangeal pivot. The palmar strap is removably attached to the first anchor and integrally fixed to the second anchor.