Suction Cup Lip Overlap Structure to Prevent Interface Cracking
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Solution Overview
Problem
Suction cups with polymeric materials of different hardnesses are prone to crack formation, reducing service life and leading to faulty gripping due to tensile forces at the interface, necessitating complete replacement.
Innovation Solution
A suction cup design with a radially inward extending outer rim portion made of a softer material overlapping the central portion, bonded through injection moulding, creating a larger bonding area and shearing forces instead of tensile forces, allowing for differentiated material properties and improved sealing flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two different polymeric materials are used in the lip, then differentiated material properties (flexibility, hardness) are achieved, but cracks form at the interface due to tensile forces, reducing service life
Solution Approach 1:
The lip is designed with different material properties in different regions: the outer rim portion uses a softer polymeric material for flexibility and sealing, while the inner central portion uses a harder polymeric material for structural strength. This local differentiation allows each region to perform its specific function optimally without compromising overall reliability.
Solution Approach 2:
The invention uses a composite structure where two different polymeric materials are bonded together in an overlapping arrangement. The softer outer material and harder inner material work together as a composite system, combining the advantages of both materials while the overlap geometry eliminates tensile forces at the interface that would cause cracking.
2Ease of operation
If a softer polymeric material is used in the outer rim portion, then sealing flexibility is improved, but bonding strength is reduced due to lower material hardness
Solution Approach 1:
Instead of relying solely on material hardness for bonding strength, the invention transitions to a geometric solution by creating a three-dimensional overlapping structure. The overlap extends in the radial direction and along the thickness of the lip, distributing bonding stresses across a larger volume and eliminating concentration at a single interface line.
Solution Approach 2:
The lip is segmented into two distinct material zones with different hardness levels, each optimized for its specific function. The softer outer segment provides sealing flexibility while the harder inner segment provides structural support, and their overlapping arrangement creates a graduated transition zone that distributes stresses effectively.
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
Enhances bonding strength, reduces crack formation, and extends service life by using shearing forces, enabling flexible sealing and stable gripping without material detachment.
Implementation Method 1
The bonding can be accomplished by means of injection moulding
Data Source
AI summary
Described is a suction cup for automated gripping operations, such as for lifting of objects, is disclosed, wherein a rim portion of a lip of the suction cup is made of a first polymeric material having a first lower hardness as compared to a second hardness of a second polymeric material of an inner, central portion of the lip. The first and second polymeric materials of the lip of the suction cup disclosed are bonded to each other with an overlap. The bonding can be accomplished by injection moulding of the suction cup.