Holmatro recently delivered two double-acting lock nut cylinders for the Polish mining sector, each with a capacity of 400 tons. Exceptional, in view of the fact that these cylinders are hardly bigger (read: taller) than gravity return lock nut cylinders. The cylinders supplied are used for machine maintenance.
Traditional double-acting lock nut cylinders are rarely supplied. This is because the build-in height of these cylinders is too high. For the double-acting version the plunger must be lengthened in order to obtain the correct guidance and seal. However, this makes the cylinder impractically tall.
Nevertheless, there is regularly demand for double-acting lock nut cylinders that make it possible to control loads with extreme accuracy. A reason for Holmatro to study the possibilities with regard to constructing this type of cylinder with a lower build-in height. The result is a completely new concept, in which the cylinder is not fitted with a stop ring, but with an intelligent return plunger. This results in a considerably lower build-in height that makes the double-acting lock nut cylinder a suitable tool for levelling, climbing, synchronized lifting and lowering.
Besides the models with a capacity of 400 tons for the Polish mining sector, Holmatro also supplies other custom-made double-acting lock nut cylinders with various tonnages and lengths of travel on request.
