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M3 Design Product Teardown www.m3design.com +1.512.218.8858 EPI PEN JR. AUTO-INJECTOR 2014 March
M3 Design Product Teardown www.m3design.com +1.512.218.8858
EPI PEN JR. AUTO-INJECTOR
2014 March
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• Introduction
• Product Teardown
CONTENTS
March 2014 – EpiPen Jr. Auto-Injector
Why, and how?
Overview External construction Systems Conclusion
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Why do product teardowns?
Part of the product development process is to apply knowledge gained from prior experience during the concept development and design phases. Some experience comes from having directly designed something in the past and other experience is more indirect. It is this indirect product development experience that is gained from product teardowns. This process serves two purposes:
1. It forces the deconstruction team to carefully investigate the product pieces and learn as much as possible about the design details. 2. It provides a detailed record of the process for future reference by other product designers.
Teardowns are different from Reverse Engineering
Reverse engineering a product is nothing more than figuring out the design and manufacturing methods, typically for copying. M3 Design views product teardowns as ways to gain insight into the design to become better product developers. We focus on "Why" questions.
• Why did the designer make the choices they did?
• Why were certain construction techniques chosen?
• Why were some features included and others left out?
• Why was the design approach chosen?
This serves to gain more in depth understanding into the product's design rather than a superficial once-over.
M3 product teardown process INTRODUCTION
March 2014 – EpiPen Jr. Auto-Injector
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How does M3 Design approach product teardowns? The product teardown process is a rigorous approach to carefully catalog the deconstruction in both pictures and written descriptions. The overall approach is outlined below.
M3 product teardown process INTRODUCTION
March 2014 – EpiPen Jr. Auto-Injector
When we come across products that claim to be unique, look complex, seem interesting, or no longer work, we want to know the “how” and “why” of the product's design. We take apart products to learn valuable lessons from other product developers. By studying how products are designed, constructed, or failed, we expand our knowledge of design solutions.
We think critically about the products as we take them apart in order to deduce the design decisions of the original developers. By placing ourselves in their shoes, we expand our experience by imagining hypothetical design constraints to answer the “how and why” questions. In turn, we learn valuable lessons that we can later apply to our own product development process and share our findings with others.
By answering the questions below, we can then apply the learning into future brainstorming, concept exploration, prototype development, detailed design, design for manufacturing (DFM), cost reduction analysis, and maintenance/troubleshooting.
• Why were specific materials or components chosen?
• How was the size and shape maintained?
• Why were certain construction or assembly techniques used?
• How were specific features or mechanisms executed?
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EpiPen Jr. Auto-Injector PRODUCT TEARDOWN
March 2014 – EpiPen Jr. Auto-Injector
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OVERVIEW
Overview of product EpiPen removed from case
March 2014 – EpiPen Jr. Auto-Injector
EpiPen Jr. Auto-Injector
One of the challenges in product design is creating products that are sophisticated yet work transparently in straightforward user scenarios. Achieving this is especially important in medical and military environments, where having to pause to read an instruction manual can mean the difference between life and death. Recently, the M3 team disassembled a simple but intimidating product – an EpiPen Jr. Auto-Injector. It is used to quickly administer epinephrine to treat life-threatening allergic reactions (anaphylaxis). The powerful yet elegant internal mechanism certainly surprised the team.
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EXTERNAL CONSTRUCTION
Over-center lid Overview of the product
March 2014 – EpiPen Jr. Auto-Injector
Construction Overview
The EpiPen is packaged in a clear plastic case with a flip-top lid. It contains a living hinge with an over-center beam that biases the lid into its fully opened position. This holds the lid out of the way in order to create an unobstructed path to slide the pen out of the case. The exterior of the EpiPen itself has three distinct sections. 1. Instruction Label 2. Safety Shroud 3. Safety Cap
Safety Cap
Instruction Label
Safety Shroud
Case
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EXTERNAL CONSTRUCTION
EpiPen with label remove3d
March 2014 – EpiPen Jr. Auto-Injector
Construction Overview
Inner mechanisms can be seen through the plastic Main Housing after removing the label. • The orange Safety Shroud can slide back into the Main Housing. • The white section on the left contains the Injection Mechanism. • Fluid in a glass Syringe is visible through the open window.
Injection Mechanism
Main Housing (clear) Safety Shroud
Window to view fluid
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EXTERNAL CONSTRUCTION
One way snaps Removing snaps
March 2014 – EpiPen Jr. Auto-Injector
Disassembly
Because the spring mechanism shoots a needle that injects a chemical potentially causing arrhythmia and seizures, we made sure that only the most junior engineer disarmed the device (don't worry, we gave him safety glasses). We also took great care not to touch the Safety Shroud until we knew the EpiPen was safe to handle. As the Main Housing of the product is a single plastic tube with no screws, the first challenge was discovering how to gain access to the internal system without removing the Safety Cap or activating the Injection Spring. This was achieved by drilling out the two sets of one-way snaps included in the design that were elegantly hidden behind the label. Once removed, the internal assemblies freely slid out from the Main Housing.
One way snaps
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SYSTEMS
Injection Mechanism
Removed Syringe with needle from subsystem Exploded Injection Mechanism (Not pictured – Syringe with needle)
March 2014 – EpiPen Jr. Auto-Injector
Injection Mechanism Subassembly
When triggered, the Injection mechanism pushes epinephrine from the Syringe. The Epinephrine Syringe and needle were removed to “disarm” the device. 4 parts make up the Injection Mechanism 1. Safety Cap. 2. Trigger Housing. 3. Syringe Driver Subassembly. 4. Epinephrine Syringe with Needle. Safety Cap Syringe Driver
Subassembly
Trigger Housing
Syringe with Needle
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SYSTEMS
Syringe Driver subassembly
Close up of Plunger Driver Rear of the Syringe Driver subassembly without safety
March 2014 – EpiPen Jr. Auto-Injector
Syringe Driver Subassembly
The Syringe Driver Subassembly contains the stored energy in the system. The collar on the Plunger Driver compresses the Injection Spring. Snaps on rear of Plunger Driver lock into Spring Housing. The snaps keep the Injection Spring compressed and ready to fire.
Spring Housing Injection Spring Plunger Driver
Snaps Snaps engaged with Spring Housing
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SYSTEMS
Inside of Trigger Housing Assembled Injection Mechanism
Injection Mechanism without Trigger Housing Close-up of snaps on Plunger Driver with Safety Cap
March 2014 – EpiPen Jr. Auto-Injector
Releasing the Syringe
Pressing the EpiPin against the thigh with 3 lbs of force drives the Syringe Driver subassembly into the Trigger Housing. Chamfered edges inside the Trigger Housing compress the snaps on the Plunger Driver, releasing the Syringe forward until the needle is fully exposed. The Injection Spring continues to extend, expelling the fluid out the needle. Post on the Safety Cap does not allow the snaps to deflect inward and release the mechanism. Acts as a safety mechanism for the device.
Chamfered edge
Safety Cap post
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FIRING TEST
Video of EpiPen firing
March 2014 – EpiPen Jr. Auto-Injector
Safety Glasses Please!
The firing video speaks for itself. https://www.youtube.com/watch?v=CxBTO0fr6Vk Injection Spring fully loaded at 25lb. Easily enough to penetrate clothing and skin in an emergency!
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SYSTEMS
Exploded Safety Shroud Mechanism Subassembly
March 2014 – EpiPen Jr. Auto-Injector
Safety Shroud Mechanism Subsystem
Safety Shroud Mechanism conceals the needle immediately after use to prevent re-use or injury.
Syringe Stop Housing
Safety Snaps
Shroud Spring Safety Shroud
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SYSTEMS
Safety Snap/Safety Shroud Interaction
Syringe is pushed into the Safety Shroud Mechanism Subassembly Syringe pushes on Safety Snaps when inserted
March 2014 – EpiPen Jr. Auto-Injector
Safety Shroud Mechanism Subsystem
Syringe Stop housing holds the orange Safety Shroud via two Safety Snaps. Shroud Spring is released by the Syringe pressing on the Safety Snaps inside the Syringe Stop Housing. Deflecting the Safety Snaps uncouples the Syringe Stop Housing from the orange Safety Shroud. This allows the Safety Shroud to move forward and protect the needle.
Syringe
Safety Shroud
Safety Snaps
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SYSTEMS
Safety Snap not deflected by Syringe Safety Snap deflected by insertion of Syringe
Safety Snaps exploded
March 2014 – EpiPen Jr. Auto-Injector
Safety Shroud Mechanism Subsystem
Safety Snaps are separate parts instead of molded into the Syringe Stop Housing. • Allows for a pivot motion about an internal pin. Pivoting helps parts not shear when deflected. • Improves reliability by not relying on plastic flexures that may creep or stress relax over time.
Safety Snaps
Safety Snap
Safety Snap deflected
Inserted Syringe
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SYSTEMS
Safety Shroud, compressed Safety Shroud, extended
Lockout Snaps on Syringe Stop Housing
March 2014 – EpiPen Jr. Auto-Injector
Safety Shroud Mechanism Subsystem
When extended, Lockout Snap features on the Syringe Stop Housing pop out to lock the Safety Shroud in position.
Lockout Snaps to Safety Shroud interaction
Lockout Snaps
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SYSTEMS
Exploded view
March 2014 – EpiPen Jr. Auto-Injector
Subassembly interaction
User presses the orange tip against their body. • Entire stack is compressed towards the Trigger Housing on the proximal end. • Tapers press the snaps on the Plunger Driver which fires the Plunger Driver and Syringe forward. • Plunger Driver continues forward and dispenses the medication. • Safety Snaps holding the Safety Shroud are released by the Syringe. • Pressure from user keeps the Shroud Spring compressed which keeps the Safety Shroud retracted. • When pulled from the skin, the Safety Shroud locks into place protecting the needle.
Injection Mechanism Subassembly
Safety Shroud Subassembly
Main Housing
Case
Label
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CONCLUSIONS
EpiPen
March 2014 – EpiPen Jr. Auto-Injector
Extremely simple device from the users perspective that upon further investigation has many complex internal mechanisms to create a reliable series of events. One input (pressure on the tip) creates two outputs (injection of medication and protection of the tip). As a single-use medical device, the error-proof design intent is elegantly executed.
Product Teardowns
