Cabinet Latch Latch

Background

I have double-door cabinets at work with a retrofitted lock mechanism that is fairly annoying when unlocked. In order to lock, the left door has a spring-loaded latch that catches when closed (holding it closed). The right door then has a sort of deadbolt lock that goes behind the left door. When it is locked, the left door is held closed by the metal latch, and the right door is held closed by the left door.

Problem

Since the left door automatically latches when closed, it is essentially semi-locked all the time. To open the left door, you first have to open the right door, then reach inside to pull the latch lever inside the left door. The is very annoying during regular use of cabinets that are unlocked 90% of the time.

Solution

This print-in-place latching mechanism I call the “Cabinet Latch Latch” is designed to hold the left cabinet latch open when the cabinets are unlocked, allowing you to open the left door without opening the right door first. When locking the cabinets, the middle section swings up allowing normal function of the metal latch & lock.

Features

• Print-in-place (proper orientation in 3mf file)
• Latch sticks in lower position: Early prototypes had an issue where vibration or closing the cabinet too hard could unintentionally disengage the cabinet latch latch. In this revision, there is an added groove and ball in the hinge between the latch parts, so the latch clicks into place when lowering
• Optional Locking Pin which can be placed in the top of the cabinet latch latch to prevent it from being easily unlatched.
• Onshape link and STEP files for remixing

Print Settings

• 0.25 mm nozzle: The tolerances are very tight between the two parts of the cabinet latch latch and a larger nozzle will most likely result in the parts being fused together.
• PETG: PLA is too brittle and breaks too easily. Stronger plastics than PETG should be fine too.
• 0.07 mm layer height: Better for capturing fine detail

Hardware

Attached to cabinet with #4 x 3/8" Pan Head Wood Screws.

Demo Video