Composite Racquet Frame with Solid Tip and Pre-Molded Holes
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Solution Overview
Problem
Extruded aluminum racquet frames lack strength and stiffness, and composite frames using bladder molding sacrifice dynamic strength and durability due to hollow structures and fiber cutting from drilling holes for string attachment.
Innovation Solution
Combining bladder molding and compression molding to create a composite sports racquet frame with a hollow and solid combination design, where solid sections enhance dynamic strength and reduce breakage, and pre-molded holes eliminate the need for drilling, preserving fiber integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If bladder molding is used to create hollow racquet frame structure, then weight is reduced, but dynamic strength and durability are sacrificed
Solution Approach 1:
The patent applies different structural qualities to different parts of the racquet frame. The throat and handle areas are made solid to provide strength and durability where needed, while the head and shaft areas maintain hollow structures to minimize weight. This local differentiation resolves the contradiction by providing strength only where dynamically required rather than throughout the entire frame.
2Ease of operation
If holes are drilled through the frame to attach strings, then string attachment is achieved, but fiber structure is cut and frame strength is weakened
Solution Approach 1:
The patent incorporates string attachment holes as pre-molded features during the composite molding process itself, rather than drilling them afterward. This preliminary action allows the holes to be formed as integral parts of the mold cavity, enabling fibers to wrap around and reinforce the hole edges rather than being cut across, thus maintaining frame strength while achieving string attachment functionality.
3Ease of manufacture
If extruded aluminum process is used for mass production, then manufacturing ease is improved, but strength, stiffness, and structural variability are limited
Solution Approach 1:
The patent transitions from monolithic extruded aluminum to composite materials consisting of fiber reinforcements (such as carbon fiber, glass fiber, or Kevlar) embedded in a polymer matrix resin. This composite approach enables both mass production capability and superior strength-to-weight ratio, while also allowing structural variability through different fiber orientations, types, and stacking sequences in different frame sections.
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 combined molding process improves dynamic and static strength, reduces weight, and maintains frame durability by focusing solid structures on impact-prone areas and using pre-molded holes to avoid fiber weakening.
Implementation Method 1
A bladder and cavity molding process is the preferred method used in today's manufacturing process of composite racquet frames. Using bladder molding allows for additional customization of the racquet frame. Combining materials, such as, carbon, Kevlar, fiberglass, boron, and other fibrous materials
Implementation Method 2
compressed air, chemical reactions to increase pressure, or hot gases to apply internal pressure within the structure
Implementation Method 3
Simultaneously, the mold and the part is heated to a temperature that accelerates the catalyst process to harden the racquet structure
Implementation Method 4
the mold and the part is heated to a temperature which that accelerates the catalyst process to harden the racquet structure
Implementation Method 5
Combining bladder molding and compression molding to create a composite sports racquet frame with improvements in dynamic and static strength
Implementation Method 6
pre-molded holes are created, eliminating the need to drill holes that cut the fibers, hence weakening the structure
Data Source
AI summary
A composite sports racquet frame including a frame made of composite material, the frame including a head portion configured to receive and surround a string bed with a plurality of string segments, and a handle portion. The head portion includes a tip section on an opposite end of the frame from the handle portion, and the tip section includes a solid cross-section substantially throughout and the remainder of the head portion includes a hollow cross-section substantially throughout.