Front	Rear	Left Side	Right Side

Front: Open for Rigging	Rear: Open for Rigging

Technical Details

I acquired my SOB from Xinqiang Yu 新强 余 (tdcq888) in 2021. It was not what I ordered, but I kept it as I did not have an SOB like this one.

My SOB is 235 mm. tall, 63 mm. wide, 31 mm. thick, and weighs 349 g.

This descender consists of a fixed plate in the rear and a pivoting plate in the front with two bollards and an autostop assembly consisting of a cam, handle, and connecting arm. The plates are each 3.3 mm. thick.

Starting at the top of the fixed plate, the autostop cam is mounted on a shoulder rivet near the top. The head and shoulder of this rivet fit into a notch in the pivoting plate.

The upper bollard sits 41 mm. lower, where it is riveted through its center. This bollard is made from aluminum alloy. It is 44.3 mm. in diameter and 13.2 mm. thick. A 4.5 mm. split pin pressed through a hole in the fixed plate prevents rotation. The rope groove is V-shaped, 9 mm. wide, and 3.2 mm. deep. The pivoting plate has a second notch that engages a shoulder area on the mounting rivet. These notches provide support to keep the pivoting side plate from bending open during descent.

The lower bollard is 48.3 mm. in diameter, 13.2 mm. thick, and also made from aluminum. Its form is that of a circle truncated by two chords. The lower bollard. rotates on a shoulder rivet attached to to the fixed side plate about 56 mm. below the upper bollard. This bollard has a 3.5 mm. deep, 9.2 mm wide V-shaped groove on its circular peripheral arcs.

A handle assembly mounted on the outside of the fixed side plate rotates on the same rivet as the lower bollard. The friction from the passage of the main rope causes the lower bollard to rotate, rotating the handle and pulling the connecting rod down. This pulls one end of the the autostop cam against the rope above the upper bollard, thus slowing the descent. The handle is used to keep the cam disengaged during normal descent, but pulling the handle too far brings the other end of the autostop cam against the rope, again slowing the descent.

The attachment point is a 13.3 by 26.8 mm. oval hole near the bottom of the fixed plate. The hole is oriented vertically. The pivoting plate has a hook with a spring-loaded metal safety.

The pivoting side plate is printed with a "reading is dangerous" icon, "1282CE," "DOWN," "ROPEO10≤Ø≤12," a rigging illustration, a logo and "SOB." The fixed side plate is printed with a rigging illustration, "EN341 (2A):11," "ROPEO10≤Ø≤12mm," MAX100m," and "MAX150kg."

Fraudulent Certification Warning: Notified Body #1282 marks on Chinese vertical equipment are fraudulent. Notified Body #1282 is Ente Certificazione Macchine. Ente Certificazione Macchine does not certify this type of gear.

Comments

The SOB is one of the following group of similar double-stop bobbins:

Image Device Upper Bollard Lower Bollard Connecting Link Safety Lever Hand Grip Hook Safety Certification Allowed Rope Size Weight Limit(s) Max Drop Kong Indy Aluminum Aluminum Flat Bar Aluminum Extrusion Ribbed Plastic Stamped Stainless Steel EN341/A, prEN12841/C 10-11 mm. (EN341/A) 10-13 mm. (EN12841/C) Max. 1.5 kN. 100 m. Camnal Down Aluminum Aluminum Flat Bar Aluminum Extrusion Ribbed Plastic Stamped Stainless Steel EN341 10-12 mm. Max. 150 kg. 100 m. SOB Aluminum Aluminum Flat Bar Aluminum Extrusion Ribbed Plastic Stamped Stainless Steel EN341 10-12 mm. Max. 150 kg. 100 m. Chinese Aluminum Aluminum Flat Bar Aluminum Extrusion Ribbed Plastic Stamped Stainless Steel EN341 10-13 mm. Max. 150 kg. 100 m. Vento Aluminum Aluminum Round Bar Aluminum Extrusion Plastic /w Finger Grooves Stamped Stainless Steel EAC 10-13 mm. Max. 150 kg. 100 m. S.E.Peak SE-218 Aluminum Forged Aluminum Flat Bar Forged Aluminum Smooth Stamped Stainless Steel EN341/A EN12841/C 10-13 mm. 30-150 kg 200 m. SUT Aluminum Steel Flat Bar Aluminum Extrusion Ribbed Plastic Stamped Stainless Steel EN341 9-12 mm. 30-150 kg 100 m. Ito-Rocky Aluminum Forged Steel Flat Bar Aluminum Extrusion Ribbed Plastic Plastic EN341 9-12 mm. 30-150 kg 100 m. NewDoar Aluminum Forged Steel Flat Bar Aluminum Extrusion Ribbed Plastic Plastic EN341 9-12 mm. 30-150 kg 100 m. Asol Aluminum Forged Steel Flat Bar Aluminum Extrusion Ribbed Plastic Plastic EN341 10-13 mm. Max. 150 kg. 100 m. Z&W Aluminum Forged Steel Flat Bar Aluminum Extrusion Ribbed Plastic Plastic EN341 10-13 mm. Max. 150 kg. 100 m.

These descenders clearly "borrow" the autostop concept from Kong and in particular from the King Indy.

These each have a lever at the top that provides both a release-stop and a panic-stop feature. Unlike the Petzl Stop design, the stop design developed by Kong-Bonaiti and copied on these ascenders has never worked well for me. It simply does not provide enough stopping force to hold me in position, let alone arrest a rapid descent. I've been able to complete rappels on these bobbins without touching the handle, a situation that should not allow me to move.

As for the panic stop feature, squeezing the handle hard enough will slow the descent. Depending on the rope in use, this may occur whn one is tring to hold the handle in the middle position for a normal descent. I've never fully understood why people promote panicing as desirable behavior, and I find double-acting levers designed to address this questionable behavior maddening. You may like them, but if this is because you like to panic, I suggest you fullly dispense with that behaviour first and then move on to single-acting devices.

This autostop design adds unnecessary length and width to the descender. It is too complicated for my taste, with too many pivoting joints that may fail. I cannot recommend this type of stop (let alone double-stop) feature over the Petzl Stop design.

The unnamed Chinese, Camnal Down, and SOB are made by the same company and sold under different names (or no name at all). Of the Kong Indy copies, these are the ones most similar to the Indy, although there are minor differences in the shape at the top of the pivoting plate.