Door-O-Clock (doorknob lever with lock control)

See images for printing instructions

Door-O-Clock (Assistive doorknob lever with lock control)

An assistive lever system designed to make circular doorknobs easier to grip and operate. The goal is to give you the leverage and grip you need to open, close, lock, and unlock doors without struggling with a round knob.

Why the name?

The design is inspired by how a clock works. the big hand grips the doorknob and rotates to open and close the door, just like you would normally turn a knob but with leverage. the little hand rotates separately around the same doorknob to engage the locking and unlocking features. The two hands moving around the circular center point work like clock hands rotating around the clock face. beyond the visual metaphor, the rotating hand system serves a functional purpose: it lets you handle opening, closing, and locking without repositioning your grip.

Project Overview

Circular doorknobs can be difficult for people with limited grip strength, arthritis, hand injuries, or dexterity challenges. Door-O-Clock adapts to many standard round knob into something you can operate with ease. it works on many knob styles including Plymouth, Oval, Orbit, Tulip, and ball-style knobs and more. It's also portable, making it great for travel when you're staying somewhere with unfamiliar doorknobs.

The lever system gives you the mechanical advantage you need. the big hand provides grip surface and the little hand handles locking and unlocking mechanisms on both sides of the door.

How the Door-O-Clock works

The system has two parts that rotate together like clock hands.

The big hand goes over the doorknob and provides the main grip surface. It includes a slit at the bottom to pick up toothpicks, so you can load them into the little hand without pinching. this makes the dual-mechanism setup much easier to manage.

the little hand slides into the big hand for alignment and stability. it has four different locking and unlocking features depending on your door type:

on one end, there's a claw-shaped peg that works with thumb-turn locks and push-to-lock mechanisms.

on the other end, there's a split peg with four sections. you insert a toothpick through these sections to reach pin-hole emergency release locks. the same peg also has a thin blade at the tip for slotted emergency release.

when you slide the little hand into the big hand with the toothpick in place, the tension keeps it stable. you can pick up the toothpick using the slit under the big hand, making the whole process smooth and easy.
 

There are little holes on the big hand and little hand so you can thread a string through it so you can hang it off the doorknob or attach it to anything you want like a wheelchair, backpack etc.

Grip and friction

The Door-O-Clock uses adhesive rubber grip tape on specific surfaces to create both hand grip and doorknob friction. here are the cutting measurements for the tape i used (https://www.amazon.ca/dp/B0FN3BZNGK):

Big hand (hand grip): 12cm x 10cm

Big hand (doorknob claw): 3cm x 1.7cm

Little hand (hand grip): 12cm x 7.3cm

Little hand (circles): 3.8cm diameter

(See pictures to see where to place the tape)

The grip tape is essential for both comfort and function. without it, the lever won't grip the doorknob properly.

Important limitations

The Door-O-Clock is not meant to be left on the doorknob for extended periods. The TPU95A material can lose elasticity over time, so it's best used for access when you need it and removed afterward. It's ideal for travel or temporary use.

While it works on many doorknob styles, it may not work on all knob designs. if your knob has an unusual shape or mounting, it might not fit properly. test it before assuming it will work on every door you encounter. The STEP files are included if you need to modify the dimensions to match your specific needs.

About 3D printing tolerances

the Door-O-Clock is 3D printed, so dimensional accuracy depends on your printer settings and calibration. the tight fit between the big hand and little hand is important for stability. if your print is too loose or too tight, you may need to adjust your flow rate or horizontal expansion settings to dial in the fit. I recommend printing the outer layer first.
 

What makes Door-O-Clock worth printing

provides leverage and grip for people who struggle with circular doorknobs

works on many common knob styles (Plymouth, Oval, Orbit, Tulip, ball-style and more)

portable and removable for travel or temporary use

operates locking and unlocking from either side of the door

two-part rotating system with multiple engagement options

includes slots and pegs for toothpick-assisted unlocking without pinching

easy to put on and take off, even by pushing with your hip

includes STEP file for printer calibration and tolerance adjustment

practical design with clear spatial function

How Door-O-Clock came to be

This project started by observing how many people struggle with round doorknobs. I noticed that the problem wasn't the knob itself, but the grip and mechanical disadvantage it created. The idea to use a rotating lever system came from thinking about simple machines and everyday objects that work well. The clock metaphor emerged naturally when i realized the two hands rotating around a circular center point mirrored how actual clock hands move. the design combines leverage, accessibility, and a bit of playfulness to solve a very real problem.

We recommend testing Door-O-Clock thoroughly before relying on it for important doors. make sure it fits your knob securely and operates smoothly.

⚠️ LEGAL AND SAFETY NOTICE

NOT A MEDICAL DEVICE: Door-O-Clock is an experimental ergonomic aid and adaptive tool. it has NOT been evaluated, approved, or endorsed by any medical or regulatory body (such as Health Canada or the FDA). it is not intended to diagnose, treat, cure, or manage any medical condition.

USER IS THE MANUFACTURER: by downloading this file, you acknowledge that you are the manufacturer of the physical object. you assume 100% responsibility for material selection, print settings, assembly, grip tape application, and safety testing.

CONSULT A PROFESSIONAL: if you have concerns about whether Door-O-Clock is appropriate for your specific situation, consult with a professional before using it.

TERMS OF USE: downloading this file constitutes your agreement to the full Tryspire Terms of Use and Disclaimer: https://www.tryspire3d.com/disclaimer-and-terms-of-use

Print Settings

Rafts: no

Supports: no

Brim: big hand (yes), little hand (yes)

Resolution: 0.2mm

Infill: 30% (gyroid)

Wall count: 5

Filament material: TPU95A

note: Print outer layer first

Support and Updates

this design is a work in progress. if you would like to support future Tryspire projects, consider visiting Ko-fi.

Website: https://www.tryspire3d.com/

Ko-fi: https://ko-fi.com/tryspire3d

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Usage and Licensing

this project is primarily licensed under the Open Community License (OCL v1): https://github.com/OpenCommunityLicence/OpenCommunityLicence

OCL allows non-commercial use, remixing, and sharing, requires attribution when distributing derivatives, and ensures that any remixes stay under a compatible non-commercial, share-alike license.

some platforms don't support OCL. on those sites, this project is offered under CC BY-NC-SA 4.0 for compatibility: https://creativecommons.org/licenses/by-nc-sa/4.0/