Push-out Latch 1
Initial prototype where the latch to lock in the pin required the user to push the pin end hard enough so that it would pop-out past the rubber latches.
The Patent Behind EverChew's Pin-Lock System
The safest way to secure a dog chew—developed through prototypes and testing, leading to our patented pin-lock design.
EverChew's holder works way different from holders that depend on squeezing or friction against the outside of a chew. Our system uses a pin that passes through a hole drilled through the chew. And the magic is that the pin is held in place by a simple rubber latch--making it easy for anyone to use.
Why a Different Kind of Chew Holder Was Needed
The design problem was straightforward: the last portion of an edible chew can become small enough for a dog to swallow. A holder only helps if the dog cannot pull that remaining piece free.
The weakness of friction alone
During development (2017-2018), friction-based approaches were tested and found flawed. Eva, my 65 pound testing dog, could always pull the chew out--unless something like a screw-down hose clamp was used. But the metal in that was unacceptable.
Based on my experience working on DARPA projects, I decided that I had to make design requirements for the holder that absolutely had to be met with the holder. Having strict requirements that couldn't be side-stepped forced me to look at outside the box, unconventional approaches to locking in the chew. Eventually I determined that a locking pin through a hole in the bully stick was needed. Then the next step was figuring out how to keep the pin in place. That's when the true invention behind the SafetyChew holder was found. A simple rubber latch that held the pin in place. Below are some images of these earlier prototypes.
Push-out Latch 2
A close up of a push-out latch prototype where the latches were urethane molded into a prototype
Hockey puck prototype
I had assumed the rubber used for hockey pucks would withstand a dog's chew, but Eva tore this one up.
Swinging Latch 1
A latch that can be pushed to either side made the final design cut. This is an initial unit made by molding two haves in urethane and gluing them together.
Designing the body
With the latch mechanism final determined, the next step was to decide what the final holder shape would be. This is a 3D printed model close to the current SafetyChew.
Bulk prototype run
For the kickstarter campaign, 12 holder bodies were made by a production shop, costing about $100 each. This is 99% of the current SafetyChew design.
Pin and latch mechanism
Below are some close-up images showing he pin and latch in the final, as-made state.
Inside the Patent: How the Mechanism Is Shown
Patent drawings are intentionally technical. These selected figures show the main pieces of the system: the pin, the holder body, the chew before and after assembly, and the latch that retains the pin.
Patented in Three Countries
The EverChew pin-lock invention was filed as an international patent family titled Securing device for animal chew. Below are three granted family members, with direct links to the public Google Patents records.
Granted / Active
United States
U.S. granted patent titled “Securing device for animal chew.” Google Patents lists John Kirby Kendall as inventor and Pup Dog LLC as the current assignee.
Granted / Active
Australia
Australian granted member of the same patent family, also titled “Securing device for animal chew.”
Granted / Active
United Kingdom
United Kingdom granted member of the same patent family, titled “Securing device for animal chew.”