Compression latches suit railway conditions

Edited by the Engineeringtalk editorial team Mar 24, 2005

Southco has signed a number of important contracts with rolling stock manufacturer Alstom Transport.

Southco has signed a number of important contracts with rolling stock manufacturer Alstom Transport.

These involve the supply of latches for all Citadis trams, and also for X'trapolis trains to be used in the Chilean city of Valparaiso by the metro operator Merval.

Alstom Transport chose Southco for its renowned Vise Action compression latch solutions.

"Compared with the latches previously used on these vehicles, Southco's Vise Action compression latches are better suited to railway operating conditions", says Jean-Patrick Briand of Alstom Transport in La Rochelle, France.

A proven solution that combines performance, strength and reliability, these latches are based on a patented mechanism that locks the latch in a position where it can be released only by rotation of a handle or use of a key, preventing panels opening accidentally or overtime due to vibration.

With a single half turn, the Vise Action latches complete two sequential motions.

First the latching pawl swings smoothly into place behind the door frame.

Finish the half turn and the latching pawl pulls up tightly against the door frame, applying up to 6.4mm of vice-like compression against the gasket.

This consistent compression makes it a more reliable, safe solution than traditional quarter-turn systems which use friction locking, a process which is often vulnerable to wear and which over time can create a risk of accidental opening.

In addition, these latches help dampen vibration which is an important benefit in terms of passenger comfort, as it significantly reduces noise levels.

They offer clear visual indicators of open/close positions and prevent wear between the pawl and the frame.

From the security point of view, they restrict access by requiring a specific tool for opening and, with the option of a completely flush design, they also eliminate pry points for vandals.

Another advantage of the Southco solution is that it is quick and easy to install.

The latch is designed for quick adjustment to precisely fit the panels used in the LRV, and can accommodate panel misalignment or manufacturing variances.

In the past Alstom Transport used adjusters to compensate for alignment defects and joints to absorb vibrations.

Each of these components had to be separately sourced, managed and installed.

The Southco solution helps overcome this in one.

Claude Pommier, Manager of the Merval Project at Alstom Transport, stresses the importance of this.

"The use of compression means we don't have problems with latch adjustment, and there's no longer a risk of misalignment".

"Skirts, covers and hoods are easier to fit onto their mountings, and the result is more reliable".

Sealed both internally and externally, this latch is designed to withstand both indoor and outdoor environments and other harsh contaminants and it meets the corrosion-resistance and sealing requirements including IP-65 and NEMA 4 standards used in the rail industry.

This makes it the ideal choice for use on external applications such as side skirts, underframe boxes, covers and other access panels, but also internally on electrical cabinets and overhead bins.

Southco's access hardware has demonstrated its robustness and longevity in numerous highly demanding railway and other environments and its wide range of stylish and ergonomic solutions can be adapted to an equally great variety of applications and operating conditions.