Snap Lock
Universal Phone Holder
for FLIT Bike
It was a collaboration design project with the folding bike company FLIT. I aim to design a universal phone holder that integrates nicely with the new bike model M2 focusing on achieving an easy but rigid clip-on mechanism.
Engineering Design/Personal project with the company as a design engineer intern
(Mechanical design focusing on mechanisms, DFM & DFA)
FLIT’s: It is difficult to find an existing phone folder that’s compact enough to fit into their folding bikes
The Problem
User’s: Most universal phone holders can’t hold securely (phone drops during cycling), and it difficult to operate with one hand
Since FLIT makes folding bikes, space limitation is the biggest challenge of this design
Design Context
Two ends of the handlebar both bend upward, leaving a very limited flat surface for the phone holder to fit in
The phone can’t fit landscape direction due to the unique shape of the handlebar
When the bike is folded, both the width and length extending out from the handlebar are extremely limited
All conditions above give strict dimension constraints on the phone holder design
There are typically two types of phone holders: those specifically designed to work with phone cases and universal ones that do not require any additional accessories. So my concept generation was based on and expanded from these two types.
Concept Brainstorming
Concept 1
Rack & Pinion + Gravity Feed + Push-Latch
Rack & Pinion + Gravity Feed
Push Latch as Locking Mechanism
To lock: slide in the phone, lever travels in slot till it reaches the top dip and locks there
To release: push phone down a bit to get lever out of the dip to release and slide it out
Concept 2
The leaf springs let the slide cam only stay at two positions, and as soon as the slide passes just over the half of the leaf spring it snaps to the other end position.
Snap Action
Slot Cam Mechanism + Over Center Mechanism
Concept 3
Slot Cam Mechanism
Two arms move in/out by rotating the slot cam disk
Over Center Mechanism as Locking Mechanism
The lever drives the rotation of the disk which subsequently drives the arms to extend and extract
When lever passes the center position, it snaps and rotates the disk to the other end position. Disk drives the slot cam mechanism to extend/retract arms.
Slot Cam + Over Center Combined!
Final Design
3D Printed Prototype
Universality
Assuming all phones have a phone case on, it can accommodate to at least 21 popular phone models in the market.
Width range: 73.1~ 82.1mm → 9mm
Height range: 10.9 ~ 12.5mm → 1.6mm
Height
Width
Design for Manufacturing (DFM)
Since the phone holder is very small in size, all components inside have been modified for smaller dimensions. The thinnest parts are only 2mm in thickness, and to achieve the mechanical strength and complex shape required, CNC-machined aluminium is the best choice
For the silicone rubber pad, it can be manufactured separately and then glued to the aluminium parts or can be over-moulded to the parts directly to achieve a better shape and easier assembly
For spring, a spring with spring constant of 0.332N/mm is chosen:
Material Selection
Finite Element Analysis (FEA)
Bill of Material (BOM)
Design for Assembly (DFA)
Exploded Diagram
Assembly Steps
Engineering Drawing