Card Holder Friction Biasing for Variable Stack Retention

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Solution Overview

Problem

Existing card holders with widthwise acting friction elements fail to securely retain cards of varying widths due to fabrication tolerances, leading to spontaneous movement or jamming, especially with stacks of different card numbers, and lack durability and efficient ejection mechanisms.

Innovation Solution

A card holder with a mechanical projection or sensor at the distal end of the leg, which engages the cards to lock them in place, and a friction pad that adjusts its pressure based on card position, using a direct mechanical coupling to ensure stable retention and efficient ejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a widthwise acting friction element is used to retain cards, then cards can be held in place, but cards of varying widths fail to be securely retained and spontaneous movement or jamming occurs

Engineering Contradiction:

Improvecard retention stabilityVSAvoidaccommodation of varying card widths

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The friction element's pressure is made adjustable through a mechanism that changes the normal force applied to the cards. This allows the system to adapt to different card widths and stack configurations, maintaining reliable retention without jamming by optimizing the friction force parameter.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The friction element is designed to be movable rather than fixed, allowing it to dynamically adjust its position and pressure in response to varying card stacks. This dynamic adjustment enables the system to accommodate different card widths while maintaining secure retention.

Inventive Principle:

Principle #15Dynamics

2Reliability

If a friction element engages the narrow side of each card, then all cards are engaged simultaneously, but the friction element causes squeezing in widthwise direction reducing durability

Engineering Contradiction:

Improvecard engagement consistencyVSAvoidfriction element durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The orientation of the friction element is changed from widthwise-acting to thicknesswise-acting. This parameter change allows the friction element to engage cards without causing harmful widthwise squeezing, thereby improving durability while maintaining consistent engagement of all cards in the stack.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of having the friction element act in the widthwise direction (perpendicular to card length), the invention inverts the approach by having it act in the thickness direction (parallel to card length). This inversion eliminates the squeezing effect on card width while still providing effective frictional retention.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the friction element is pressed onto the cards stack, then cards are retained against gravity, but the friction element wears down quickly reducing service life

Engineering Contradiction:

Improvecard retention forceVSAvoidfriction element service life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

4Reliability

If a mechanical projection locks cards in place, then spontaneous movement is prevented, but ejection mechanism complexity increases

Engineering Contradiction:

Improvecard position stabilityVSAvoidlocking and ejection mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking and ejection functions are merged into a single integrated mechanism. The same mechanical projection that provides locking also enables ejection through a unified actuation system, reducing overall device complexity while maintaining reliable card position stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mechanical projection serves multiple functions: it acts as a locking element to prevent spontaneous card movement, and simultaneously serves as part of the ejection mechanism. This multi-functionality reduces the number of separate components needed while achieving both objectives.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 secure, durable, and efficient retention of cards, preventing spontaneous movement and jamming, while allowing easy ejection and selection of individual cards, with a design that adapts to varying card numbers and sizes.

Implementation Method 1

a friction element opposing displacement of ejected cards in card ejection direction by gravity alone

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

a mechanical projection or sensor at the distal end of the leg, which engages the cards to lock them in place

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

a leg shaped element extending longitudinally from the housing inside the card receiving space which carries a friction element

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20260013609A1Credit card holder having adjustable bias friction element

Publication Date: 2026.01.15 R J VAN GEER BEHEER BV

AI summary

A holder for cards, comprising a housing which tightly fits around a stack of at least three cards and has a card opening for locating and removing cards, while within the housing, opposite the card opening, a card eject feature is provided such that the cards through the card opening can be partly slid from the housing. At the inner side of the housing a friction element is located to provide the cards a stable position inside the housing. The friction element is associated with movement means of the housing to selectively generate a movement of the friction element or at least its friction surface in thickness direction of the friction element, which is the direction in which the friction element is urged against the stack, which also is the widthwise direction.