Door-O-Clock

For full safety information, disclaimers, and terms of use, visit: www.tryspire3d.com/disclaimer-and-terms-of-use 

Project Overview

Door-O-Clock is a purpose-built lever system designed to make round doorknobs easier to grip and operate, especially in places you don't control. Whether you're navigating a hotel room, a rental, or a relative's house, the goal was to eliminate the fine-motor grip strength that round knobs demand and provide a lever-based, travel-ready alternative that handles opening, closing, and locking. 

The project resulted in a two-part rotating system: a large lever for grip and turning, paired with a smaller lever for lock control, both mounted around a central clamp that adapts to different knob diameters. 

Design Focus

The project was built around two core pillars: leverage and lock compatibility: 

• Big Hand, Little Hand Separation: The large lever handles the primary task of gripping and turning the knob, while the small lever independently manages locking and unlocking. Splitting the two functions across separate levers means each hand movement stays simple and purposeful, rather than trying to grip, turn, and manipulate a lock all with the same motion. 

• Interchangeable Locking Pegs: The small lever accepts swappable pegs configured for thumb-turn, push-button, pin-hole, and slotted emergency-release mechanisms, covering most lock types you'll encounter away from home.

• Clamp-Based Mounting: The base clamps securely around the knob without permanent modification, so it can be added or removed in seconds and doesn't interfere with anyone else using the door.

• Travel-Ready Footprint: The compact, removable build was designed to pack easily, so it can travel with you rather than staying fixed to one door.

The Assembly System

• Big Hand (TPU 95A): The primary structural component, printed in flexible TPU 95A. The claw wraps around the doorknob for turning leverage. Adhesive rubber grip tape is needed on the inside of the claw and along the handle to provide the friction needed to grip and turn the knob reliably.

• Small Hand (TPU 95A): The lock-control component, also printed in TPU 95A. Pegs are built into either side of the small lever, covering thumb-turns and push-buttons for everyday locking, plus emergency unlock features like a slot and pin-hole. Adhesive rubber grip tape is also applied to the small hand's handle for a secure hold while turning.

Functional Breakthrough

The turning point for this design was recognizing that grip difficulty and lock operation are two separate problems that most doorknob aids try to solve with a single mechanism. By splitting the lever into a big-hand and little-hand assembly, you get full leverage for turning without sacrificing independent control over locking, something a single wraparound lever can't offer.

It's important to note that knob diameters and lock mechanisms vary between manufacturers. The clamp is designed to accommodate a range of standard sizes, but a tight or unusually shaped knob may require minor adjustment or a printed shim for a secure fit.

Reflection & Tools

• The priority was independence and portability: clamp it on, use both levers, take it with you.

• CAD: Plasticity

• 3D Printing: Prusa CORE One

• Slicing: PrusaSlicer

Disclaimer & Safety

NOT A MEDICAL DEVICE: Door-O-Clock is an experimental assistive prototype. It has NOT been evaluated, approved, or endorsed by any medical or regulatory body (such as Health Canada or the FDA).

NOT TESTED FOR EMERGENCY RELIABILITY: The emergency unlock features (slot and pin-hole pegs) have not been tested or validated for reliability in an actual emergency situation. Do not depend on this device as your sole means of emergency egress or lock access.

MATERIAL WEAR: TPU is flexible and can wear, stretch, or deform with repeated use. Inspect the lever periodically and stop using it if it shows cracks, thinning, or loss of grip.

FIT VARIES BY KNOB: Doorknob shapes, diameters, and lock mechanisms vary by manufacturer. Fit and function are not guaranteed on every round knob or lock type, test before relying on it.

PROPERTY USE NOTICE: If using this on a door you don't own (hotel, rental, someone else's home), you're responsible for confirming it's permitted and won't damage the property.

CONSULT A PROFESSIONAL: If you're using this as part of a rehabilitation or accessibility plan, consult with your OT or PT to ensure this tool fits your specific needs.

USER IS THE MANUFACTURER: By downloading these files, the user acknowledges they are the manufacturer of the physical object and assumes 100% responsibility for material selection, print settings, fit testing, and safe use on any lock or door.

For full safety information, disclaimers, and terms of use, visit: www.tryspire3d.com/disclaimer-and-terms-of-use 

Evolution of the Design