The Von Duprin 050393 is the OEM latch tail spring for the Von Duprin 88 Series Rim exit device, sold as a package of 10. It is Item 6 in the EO, DT, and NL center case parts diagram per the Von Duprin 88 Rim Series Parts Manual (July 2009), and Item 7 in the TP and K/L center case diagrams. The same spring part number covers all six center case configurations in the 88 Rim catalog: EO/DT/NL panic, TP panic, K/L panic, EO/NL fire, TP fire, and K/L fire. One part number, one pack, one order for any 88 Rim spring replacement regardless of trim function.

The 10-pack format is the practical format for field service. A single 88 Rim device uses one latch tail spring, so a pack of 10 covers a multi-device service run across a building without the cost and wait time of ordering individual springs per device.

What the Latch Tail Spring Does in the 88 Rim Center Case

The latch tail is the mechanical extension inside the center case that transfers the pushpad depression motion to the latch bolt. When someone presses the pushpad, the center case actuating mechanism drives the latch tail, the latch tail retracts the bolt from the strike, and the door swings open. When the pushpad is released, the latch tail spring pulls the mechanism back to the rest position, and the latch bolt re-extends into the latched position.

That return function is everything. Without the spring doing its job correctly, the latch tail doesn't return cleanly after each pushpad operation. On a high-traffic door this can show up as sluggish pushpad return, incomplete latch re-engagement after the door closes, or a bolt that stays partially retracted. Any of those symptoms means the door isn't latching reliably - which is a code compliance problem on any fire-rated or life safety egress door.

Spring fatigue from repeated compression and extension cycles. On institutional doors that see hundreds of operations per day, latch tail springs wear out faster than most installers expect. A building with 10 or 20 Von Duprin 88 Rim devices will typically see multiple spring failures across the installed base within a few years of each other, because all the devices were installed at the same time and see comparable use. Ordering a 10-pack and addressing all the springs in one maintenance visit is more efficient than responding to individual device failures one at a time.

Von Duprin 88 Rim Exit Device: Center Case Parts Context

The 050393 spring sits in the center case alongside a set of companion parts, all individually orderable per the 88 Rim Parts Manual:

050501 = 88 Rim Master Cam (1 per device - the cam that drives the latch tail mechanism from the pushpad input).

050502 = 88NL Cylinder Cam (1 per device - specific to NL outside trim, controls the outside cylinder interaction).

090001 = 88 Rim Latch Bolt Axle Pkg, pack of 4 (the axle around which the latch bolt pivots).

090002 = 88 Rim Center Case Rivet Pkg, pack of 10 (rivets that hold the center case assembly together).

The 050393 latch tail spring (Item 6 or 7) is the only spring in the center case parts list - there is no alternate spring for any center case variant. The same spring serves the EO exit-only function, the DT dummy trim function, the NL night latch function, the TP touch pad function, and the K/L knob-or-lever trim function. This means a single stock of 050393 covers any 88 Rim device on a job site regardless of how the outside trim was specified.

SecurityParts stocks OEM Von Duprin 88 Series exit device parts.