I acquired my Advanced Ropeclimbing Technology Spiderjack from WesSpur Tree Equipment in 2009.
The Advanced Ropeclimbing Technology Spiderjack is 135 mm. tall, 79 mm. wide, and 44 mm. thick, and weighs 238 g. It consists of an aircraft aluminum body with a friction clutch, a spring-loaded carabiner attachment arm, a release lever, and a wooden brake block on a pivoting arm.The body is a roughly-circular cylinder with a large central slot that nearly bisects the block, and two thin lateral slots. The circular diameter is 48.1 mm., and a slight extension on one end increases the length to 52.3 mm. The block is 31.7 mm. thick. The friction clutch and carabiner attachment arm pivot in the central slot. The friction clutch is is a chordal segment of a circular disk, cut away on the flat side and the top corner with a concave surface to match the rope diameter. It pivots on a pin that passes through from one side. The carabiner arm is 60 mm. long and 10 mm. thick along most of its length, widening at the base to fit the slot. There is a small oil hole in the base of the arm that passes down to the pivot. The carabiner eye is 15 mm. in diameter. A thin double-coil spring, attached to the body with a machine screw and washer, opposes the carabiner arm at one extreme of it's travel.
The release lever is 50 mm. long, tapered, and has a U-shaped cross section. It is pinned to the main block, and a set screw secures one of the pins. During use, the release lever sits horizontally; pulling it down allows the device to slide.
The wooden brake block is mounted on a U-shaped strip of 1.8 mm. aluminum that pivots in the lateral slots in the body. The block is a dark hardwood, with a rounded tip. During use, the block drops out of the way, but the user can raise it as an aid to descending and ascending.
A plastic cover on on one side of the body holds the various pivot pins in place. There is a double-faced velcro™ strip screwed to the other side.
The final piece is a section of reinforced rubber tubing that looks like a piece of hose from my truck's engine. It functions as a spacer.
The body of the Spiderjack is marked with "EN358," a book-with-an-"i" icon, the ART tree logo, "CE0123, and "0802003" on the side, and with two stacked inverted "V"s on the circumference, pointing toward the wooden brake block. The brake arm is marked "Spiderjack " on both sides. The release lever is marked "ART." The carabiner attachment arm is marked "ART" on one side and "P 09" on the other. The clutch block is marked with two stacked inverted "V"s pointing toward the wooden brake block, "Ø11-13" and "KB.SP." All of these markings are in dot-matrix form. The machine screws holding the cover on have "8.8" and "UM" marked on their heads. The machine screw holding the velcro™ has "8.8" and "S" marked on its head. The hose spacer has "rieb" printed on it.
The Spiderjack is another variation on the idea introduced in the Buckingham
Lockjack. The Spiderjack is specially designed for arborists "Double Rope Technique." The climbing line goes through the Spiderjack, up over a tree limb, and back down to the carabiner connecting the Spiderjack to the Tarzan. The spacer separates the eye splice in the main line from the eye of the device, and the velcro™ secures the main line to the side of the device.
The Spiderjack is very well made. I'm not qualified to evaluate it for arboreal suitability; cavers and climbers avoid double rope technique and will want to pass on this device.
My Spiderjack came with a 67-page manual, with instructions in five languages and additional notes in eleven more. The manual includes 32 photographs showing how to rig and use the device. Overall, I think it is a very good manual, despite the author's inability to resist following the European practice of using incomprehensible icons as a substitute for effective communication.At least they provided a legend!