Lightweight Liposuction Handpiece With Cam-Driven Reciprocation
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Solution Overview
Problem
Existing liposuction devices with powered handpieces are expensive, cumbersome, and require difficult sterilization procedures, often using pneumatic or electrical motors that are heavy and costly, with complex reciprocating mechanisms that are hard to produce at a low cost and are not easily recyclable.
Innovation Solution
A lightweight, disposable handpiece with a simplified design using a cam mechanism driven by an electric motor, where all components are made from a single polymer family, and a cam within a ring transforms rotational motion into reciprocal translation, allowing easy recycling and eliminating the need for sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a pneumatic reciprocating mechanism is used, then the reciprocating movement can be controlled, but the handpiece becomes heavy and cumbersome
Solution Approach 1:
The patent replaces the pneumatic reciprocating mechanism with an electric motor-driven reciprocating mechanism. The electric motor (50) drives a cam (4) that converts rotational motion into linear reciprocating motion of the hollow tube (2). This substitution eliminates the need for pneumatic hoses and heavy pneumatic components, significantly reducing handpiece weight while maintaining controlled reciprocating movement.
2Speed
If an electrical motor with crankshaft mechanism is used, then reciprocating movement is achieved, but the production cost increases due to complex hinge-couplings
Solution Approach 1:
The patent substitutes the traditional crankshaft mechanism with a cam mechanism. The cam (4) is a simple rotating component with an eccentric profile that directly converts rotational motion from the electric motor into linear reciprocating motion of the hollow tube (2) through the ring (3). This eliminates the need for complex hinge-couplings, connecting rods, and other intricate mechanical linkages, significantly simplifying manufacturing and reducing production costs.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate components from the reciprocating mechanism. By using a direct cam-driven system, it removes the crankshaft, connecting rods, and multiple hinge-couplings that would otherwise be required to transmit motion from the motor to the hollow tube, thereby simplifying the overall structure and reducing manufacturing complexity.
3Speed
If a rack and pinion mechanism is used, then reciprocating movement is achieved, but the bearing insertion complexity increases
Solution Approach 1:
The patent replaces the rack and pinion mechanism with a cam mechanism. The cam (4) rotates within the ring (3) opening, and the ring is rigidly coupled to the hollow tube (2). This direct cam-ring interaction converts rotational motion to reciprocating motion without requiring rack and pinion gears or complex bearing insertions, significantly reducing device complexity and assembly difficulty.
4Reliability
If a disposable handpiece is used, then sterilization is eliminated, but the components must be made recyclable
Solution Approach 1:
The patent applies homogeneity by manufacturing all handpiece components (housing, cam, ring, hollow tube, etc.) from the same polymer family, specifically thermoplastic materials. This uniform material composition enables the entire handpiece to be processed together through recycling methods such as incineration or reprocessing, eliminating the need for disassembly or material separation and facilitating easy recyclability while maintaining the disposable nature of the device.
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 low-cost, lightweight, and ergonomic handpiece that is disposable, reducing production costs and waste, while maintaining reliability and ease of recycling, and eliminating the need for sterilization after each use.
Implementation Method 1
a cam (4) mounted on a rotation axle (4r) parallel to a second transverse axis (Z) normal to the plane (X, Y) and set at a fixed position relative to the housing (1), the cam being engaged in the opening (3o), wherein upon rotation about the rotation axle, the cam is configured for rotating within the ring and defining a largest radius of rotation (ρ) defined on the plane (X, Y), and wherein the largest radius of rotation (ρ) is not more than half the length, L, of the opening (ρ4) engaged in the opening (3o) of the ring (3) drives a reciprocal translation of the hollow tube (2) back and forth along the longitudinal axis (X)
Data Source
AI summary
A powered handpiece for imparting to a cannula of a medical device a reciprocal movement of amplitude (Δx) along a longitudinal axis (X) is provided. A housing (1) at least partially encloses a hollow tube (2) extending along the longitudinal axis (X) between an inlet end (2i) and an outlet end (2o), the inlet end (2i) being configured for coaxially coupling the hollow tube (2) to a hollow cannula (10). A ring (3) rigidly is coupled to the hollow tube (2) and has an opening (3o) defined on a plane (X, Y), having a length, L, Y⊥X. A cam (4) mounted on a rotation axle (4r) parallel to a second transverse axis (Z) normal to the plane (X, Y) (i.e., X⊥Y⊥Z), offset from a centroid (C) of the cam on the plane (X, Y) by a distance (δP), and set at a fixed position relative to the housing (1), the cam being engaged in the opening (3o).