What is a pull spring feature?
The extra step of smart lock rotation makes automatic unlocking even better and is a must-have for handle-less doors.
Recall what happens when unlocking the door with a key. You rotate it inside a lock, hear a click, and the mechanism unlocks. You can press the handle and enter.
But if you rotate the key slightly more against a springy resistance, the door bounces off the doorframe. No pressing the handle is necessary.
This is where the smart lock’s pull spring feature comes in. This little extra rotation makes not just unlocking electronic but can also make “pressing the handle” smart.
This aspect of the smart lock’s operation may seem tiny but plays a crucial role in the automatic unlocking feature or if your door has a non-moving knob or handle on the outside.
Learn more about how a door lock and pull spring feature work below.
How a lock works
Looking at your lock from the door’s edge, you can usually see two types of moving parts. Look at the image above and corresponding descriptions.
A bolt is the solid metal block or a set of pins controlled through your door lock mechanism as you rotate the key. When the door is locked, the bolt(s) protrude from the door wing into the slots in the doorframe, protected by metal strike plates.
In short: the bolt makes your door locked or unlocked as you rotate the key.
A latch is a separate piece – the one with a steep side as if a triangular shape. In opposition to the bolt, it is mounted on a spring and yields by pressing it with a finger. It is never physically blocked.
The latch is controlled with a handle – it hides after you push it. But it is also connected to your lock and hides at this last extra key rotation at unlocking.
In short: the latch keeps your door shut after you close it and enables opening only after pulling the handle.
Rotating the key hides or protrudes the bolt(s). When pushed to the maximum, the key hides the latch when you’re unlocking. Rotating the key works as if you press the handle.
Smart lock not just unlocks but pulls the spring (= “presses the handle”) electronically.
Pull spring feature for hands-free entry
As a mechanism physically rotating the lock, a smart lock enables pulling the latch, too. Combined with smart technologies, this enables easier or even hands-free entry to your place.
If the door to your place opens inwards, pulling the spring, combined with automatic unlocking of a smart lock, allows for entering without touching the door’s handle. If the latch is hidden electronically, the door wing bounces off the frame, so you can push it to enter.
Perfect for grocery runs or if you prefer not to touch the handle of doors in common areas.
If your door opens outwards, probably this feature does not elevate the automatic unlocking experience and hands-free entry this much. Unless you can manage to open the door with your foot 😉
A necessary feature for handle-less doors
Some doors use not a pressable handle but a non-rotating doorknob or another fixture not connected to the lock. In such cases, the pull spring feature makes unlocking a smart lock from the outside available.
In these doors, the latch is pulled only after the full rotation of a key. This makes absolutely no issue when unlocking manually, as your key is already inserted. But without a pull spring feature, the smart lock would only unlock your lock’s bolts but would not move it away from the frame.
If such a door is unlocked, but you need to open it and enter, you can pull the spring on open doors in the app – just as you would unlock it.
What you need to know
The pull spring feature can work in both automatic and remote unlocking operations. However, the door would be not just unlocked but slightly open.
In such situations, the lock has no chance to lock the door back without pressing the door to the doorframe.
In practice: if you unlock the door remotely with a pull spring feature, but there is nobody there to close it shut, the door would stay unblocked, with no chance to be automatically closed and locked.
Make sure to be extra aware of that when using the remote features of a smart lock. You can disable the pull spring.
How to enable the pull spring feature
The pull spring feature is enabled in your lock settings. It begins with a dedicated calibration step.
After enabling, the settings allow for enabling and disabling pulling the spring in automatic unlocking operations. You can set up the offset time: how many seconds after unlocking the spring is pulled.