I'm pulling the lowering lever, why won't the forks on my pallet jack go down all the way?

Different Types of Fork Lift Trucks
Forklift trucks are very powerful industrial trucks that are used for
both lifting and transporting of materials.These days building
projects all use forklift trucks.
There are many different types of forklift truck. Here are some of the
most well known;

Electric forklifts - these forklifts are powered by lead-acid
batteries and includes scissor lifts, stackers and pallet jacks

Sideloader - this includes both Stand on End Control and Sit Down End Control.

Hand pallet truck - a pallet truck that is usually electrically powered.

Truck mounted forklift - usually a diesel run truck.

A small percentage of the forklift truck market includes high-end
speciality trucks.

In more recent years, Automated forklift trucks have been developed in
order to try and reduce the wages paid and operational costs of
running regular trucks. The popularity of automated forklifts has
grown massively.