pneumatic cylinders hold out an array of features in electronics, automotive, and packaging industries. Their essential purpose is consistently a comparable — linear advancement of loads by attachment to some metallic piston, pushed to and fro by columns of air. At some place in every solitary and every application, however, a cylinder should slow down, stop, and alter direction. especially how that requires place determines how nicely the cylinder will hold out in cycling applications.

Air throttle
When an uncushioned piston reaches one accomplish of its stroke, it slams to the accomplish cap, making a difficult metal-to-metal impact. The result is sometimes so loud that its exceeds OSHA specifications for workplace noise. quickly after the impact, the piston may nicely bounce, through which time, the pneumatic cylinders movement is technically uncontrolled. The huge amplitude, high-frequency result could also harm the cylinder, at the same time to surrounding equipment.

Avoiding this kind of troubles and decelerating piston rods within a controlled method calls for exterior or inside cushioning. exterior cushioning employs a shock-absorbing mechanism outside the cylinder's whole body to absorb piston impact. The drawback is steering to be the simple fact that it raises the footprint in the cylinder and adds surplus weight and relocating parts. inside cushioning, concerning one other hand, operates inside the cylinder footprint and tends for getting simpler in function.

Here's how inside cushioning works: At end-of-stroke, a piston rod tactics the pneumatic cylinders accomplish and squeezes oxygen out; a flow vent meters oxygen for controlled velocity. Just before to impact, a cushion spear or sleeve jumps into action, blocking the cushion seal and eliminating the exhaust path. The controlled quantity quickly decreases, compressing the gas. Exhaust is then metered out even extra slowly, by method of a cushion needle, completely decelerating the piston before to it contacts the cylinder end.

The oxygen cushion by itself is adjustable, so the quantity of oxygen released may nicely be metered through compression. A threaded needle screw piercing an orifice concerning the accomplish hat provides the adjustment. Turning the screw even more to the orifice decreases the quantity of oxygen that will escape within a granted time. This diminished exhaust produces backpressure for an even extra significantly decelerated piston.

Physics produces it possible
The physics involved within a cushioned oxygen cylinder is pretty straightforward. The laws of physics need that the bad force work over a piston to decelerate it. This requires place when oxygen is squeezed or compressed while in the accomplish cap, and may nicely be mathematically understood.

Two troubles really steer obvious of pistons from colliding with accomplish caps. one is steering to be the deceleration in the piston with an auxiliary (cushion) system. one other is drag. Pistons (and loads linked to them) slow decrease quickly when — before to hitting any oxygen cushion — the actuator reaches equilibrium among the net producing and frictional force: