Front	Side

Open for Rigging	Disassembled

Technical Details

I acquired this Zipline Trolley from E. M. Grillos in 2020.

This Zipline Trolley is 200 mm. long, 203 mm. wide, 72 mm. high, and weighs 1361 g.

This trolley consists of two rollers and a brake fitted between two side plates. Three quick-release pins hold the assembly together. Each side plate is subtriangular, 160 mm. wide, 134 mm tall, and 6.5 mm. thick, and made from aluminum alloy (perhaps 6061?). The corners are rounded with about a 20 mm. diameter for the upper two and 14 mm. for the lower one. There are three 9.7 mm. holes in each plate. The upper holes are countersunk on the inside to clear a boss on the bearings.

Each roller is a Norma XF-94 sealed bearing aluminum roller. These are 17.4 mm wide and 40 mm. in diameter, with a shallow 1 mm. deep U-shaped peripheral groove. The inner bearing is 14.5 mm. in diameter and 22 mm. long. When the trolley is assembled, these extensions fit into the countersunk upper side-plate holes, helping to prevent racking.

The brake is an irregular shape cut from 19 mm. aluminum alloy (again, perhaps 6061). The shape provides a hand grip at one end and a 19 mm tie-in hole at the other. A 106 mm. long, 9.4 mm. diameter quick-release pin passes through a hole in the lower end of the hand grip and into an opposing hole drilled into the upper portion of the arm.

The rollers are stamped with "NORMA," "XF 94," and "MADE IN USA." The three upper quick-release pins are stamped "6F3A6-1.312" (the distance from the shoulder to the retaining balls is 1.312 inches, or 33.3 mm.). The long QR pin is printed with "9042," although this is faded and hard to read.

Comments

I bought this device on eBay. The seller described the device as follows:

Vintage 1960’s Mountaineering Climbing Trolley -Zip Line Applicable. Never actually used, great condition, only listing it as used as it has years of shelf wear.

All locking pins work as they should. The ball bearing rope rollers are tight and right. Machined aircraft aluminum and handle designed to act as break [sic].

This looks like it was a well-made home-built item rather than a commercial product.

When the user is supported by the eye, the brake rotates, and the upper surface squeezes the rope between the upper surface of the brake and one of the rollers. Pulling down on the handle reduces he breaking force. There are too many variables that affect how well this works to make a general statement about its effectiveness. The most important are how steel the zipline is rigged, the user’s body build, and where the user’s body is balanced in their harness.

While the upper QR pins allow one to quickly disassemble the device, there should not normally be a need to do so in the field. These pins could be replaced by bolts if one prefers to do so.

I'm not sure what purpose is served by the QR pin in the handle. I would not recommend attaching a chest harness to the handle, since leaning back would fully defeat the braking action.