Sheet Dispenser Hold-Back Tabs for Low-Friction Napkin Feeding
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Solution Overview
Problem
In-counter dispensers and similar devices face issues with napkin tearing and accidental bunching due to excessive friction when using springs or gravity to dispense sheet products, especially when mounted vertically, as the spring force becomes too great, leading to unwanted dispensing failures.
Innovation Solution
The dispenser employs hold-back tabs that project from the side of the product housing to engage the border of the stack, reducing frictional engagement with the interior surface, allowing for smooth dispensing with minimal force and preventing bunching, while the tabs are designed to be flexible and retractable for easy loading and unloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring force is increased to ensure napkins are forced against the front wall for the whole range of depletion states, then the napkins are reliably positioned for dispensing, but excessive friction is created causing tearing and accidental bunching
Solution Approach 1:
The front wall is segmented into a rigid support structure and a flexible hold-back member that can independently deflect. This allows the rigid portion to provide stable support while the flexible portion reduces friction contact with the napkin stack, preventing tearing and bunching while maintaining reliable positioning.
Solution Approach 2:
The hold-back member's flexibility parameter is optimized to balance two opposing requirements: enough stiffness to hold the napkin stack against the front wall for reliable positioning, but enough flexibility to reduce friction and prevent tearing. The deflection capability allows the contact pressure to be dynamically adjusted based on stack weight.
2Adaptability or versatility
If the dispenser is mounted to a vertical wall, then counter space is freed up and the dispenser is less conspicuous, but the spring force becomes too great causing tearing and bunching issues
Solution Approach 1:
The flexible hold-back member acts as a mechanical counterbalance to the spring force. When the dispenser is mounted vertically, the hold-back member deflects under the weight of the napkin stack, automatically reducing the contact pressure and spring force effect on the napkins. This compensates for the increased spring force effect in vertical mounting orientations.
3Reliability
If the hold back tab projects further into the interior volume to securely engage the stack, then the stack is held back more effectively, but the contact area with the front face increases causing more friction
Solution Approach 1:
The hold-back member is made from a flexible material that can deflect and conform to the napkin stack. This flexibility allows it to engage the stack securely at its border edges while maintaining minimal contact area with the front face, thereby preventing tearing and bunching while ensuring reliable hold-back security.
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 effectively reduces the risk of napkin tearing and accidental bunching, ensuring smooth and controlled dispensing regardless of the dispenser's orientation, maintaining functionality and reducing maintenance complexity.
Implementation Method 1
The frictional engagement with the at least one tab is relatively low. Accordingly, the front most napkin in the stack can be dispensed with a relatively low dispensing force
Data Source
AI summary
A dispenser design including a hold back means. The dispenser includes a product housing (2) and a cover (6). The dispenser includes a flange (8) at the front of the product housing so that the product housing passes through a cut-out in a wall, such as a countertop, for the flange to seat on a front surface of the wall. The cover is pivotally mounted so as to pivot between an open position providing access to the interior volume defined by the product housing for loading a new stack of sheet products and a closed position so that the sheet products are only accessible through a dispensing opening (7) in the cover for one at a time dispensing of sheet products from the product housing. Hold back means (15, 16) is provided in the form of first and second tab- like members projecting from an interior surface of the product housing into the interior volume (11), the interior volume being for accommodating a stack of sheet products. With the cover open, the first and second tab-like members engage in a margin or border area of a front face of the sheet products positioned closest to the dispensing opening to hold at least the engaged part of the sheet products spaced from an interior surface of the anterior cover.