Hydraulic point machine

In response to user requirements and the new locking mechanisms used in Hungary, Műszer Automatika Ltd. developed the HVH-01-K family of point machines installed beside the track, based on the MA-HVH (01/D, 02) hydraulic point machines that we have been manufacturing for a long time.

The family can operate turnouts with conventional clamp locks or Spherolock locking, and large-radius turnouts with Hydrolink power transmission. It locks them hydraulically or mechanically, and detects and reports their end position electrically.

The connection interfaces of the drive rod and the detection rods of the MA-HVH-01-K family are identical to the conventional solution, so it is compatible with all point machine types used so far.

Types

MA-HVH-01-K-

• D1/ – single-phase
• D2/ – two-phase
• D3/ – three-phase

All members of the family are trailable. The trailing resistance can be set between 9 and 12 kN and is set to 10 kN in the factory. In the "A" type machine, locking in the end position and the trailing resistance are provided by two brake valve blocks mounted on the hydraulic cylinder and the brake valves built into them. After removing the protective cap, the brake valves can be adjusted to the requirements of the operating environment. The "A" type machine also has a so-called mechanical latch, which – independently of the hydraulic locking – provides mechanical locking against residual forces.

The "B" and "C" versions are fitted with a hydraulically released mechanical locking unit, so the trailing resistance is provided jointly by the hydraulic locking and the hydraulically released mechanical latch. The disc-spring latch has a holding force of 5.5–6 kN. Thanks to the chosen design, it causes no problem in operation if the force needed to throw the points exceeds the trailing/holding force: the points are still thrown and locked in the end position without any self-trailing, throwing or locking problems.

The machine can be reversed immediately during a throw and can be operated by hand during a power failure. Manual operation uses a hand pump connected to the hydraulic circuit; the direction is selected with a change-over valve. The hand pump is accessed through a door in the machine cover, opened with a special key. Through the same door – without removing the cover – the hand crank can be taken out and put back after manual operation. The length of the crank was chosen so that manual operation is easy, with little effort, even for large-radius turnouts with a Spherolock–Hydrolink system requiring a throw force of 6.5 kN. Thanks to the position of the hand pump, there is a clear view of the track in both directions during manual operation, which reduces the risk of accidents.