Next Return Previous

Russian Stop Bobbins

Version A

Version B

Version A Version B
Version A Version B

Overview


Version A
(#518)

Front View Rear View Side View
Front View Rear View Side View
 
Front View: Open for Rigging Rear View: Open for Rigging
Front View: Open for Rigging Rear View: Open for Rigging

Technical Details

I acquired this descender from Theresa Williams and Maury Benamy in 1995.

Version A is 220 mm. tall, 62 mm. wide, 27 mm. thick, and weighs 255 g.

The side plates and handle are stamped from 2 mm. stainless steel. Unlike most stop bobbins, the handle lies on the right when the pivoting side plate is up. The pivoting side plate has a spring-loaded, stamped gate that allows one to rig the bobbin without unclipping from the seat harness.

The lower bollard is part of an autostop assembly. The upper surface of the bollard is milled flat and a J-shaped piece of 4 mm. steel is inset and screwed to the bollard. This protrudes at the 2-o’clock position and acts as a cam much like on the Petzl Stop, Version A. The handle is attached to the fixed side plate side of the lower bollard - I cannot see how without disassembling the device; however, the J-shaped piece extends to the side and fits into notches in the handle, keeping the handle and bollard from rotating with respect to each other. The handle portion is bent into a U to increase thickness, then covered with a plastic grip for comfort. The lower bollard and handle assembly rotate on a shoulder nut on the lower bolt. Friction from the main rope’s passage tends to turn the lower bollard and force the toothed cylinder towards the upper bollard, thus locking the rope and ideally arresting the descent. The rappeller uses the handle to keep the autostop feature disengaged. Alternately, a hole in the handle plate opposite the handle itself allows one to clip a carabiner in, thus disabling the autostop feature by preventing rotation of the lower bollard assembly. A small cutout in the fixed side plate provides clearance for this carabiner.

The upper bollard is mounted on the pivoting side plate (another deviation from normal practice). The front side of the bollard has a shallow milled groove that the front plate sits in; this keeps the bollard from turning. The bollard is cut away on its lower side to provide a flat surface to act as an anvil for the cam action of the autostop feature.

The only markings on the device are "50G" (the G is actually a capital Gamma) on each bolt head.

Comments

This is a copy of the Petzl Stop, Version A, yet executed well enough to trust in practical use. Users used to other bobbins might find it "backwards," but some (such as those who rappel left-handed) might prefer the mirror-image arrangement.


Version B
(#973)

Front View Rear View Side View
Front View Rear View Side View
 
Front View: Open for Rigging Rear View: Open for Rigging
Front View: Open for Rigging Rear View: Open for Rigging

Technical Details

I acquired this descender from Serguei Khramtsov (from Ural Sport), who did some shopping in Russia for me in late 2004.

This descender is 208 mm. tall, 74 mm. wide, 30 mm. thick, and weighs 286 g.

The side plates and handle are stamped from 3 mm. aluminum, then painted. The pivoting side plate has a stamped steel gate that allows one to rig the bobbin without unclipping from the seat harness.

The upper bollard is very similar to Petzl’s. The upper bollard is cut away on its lower side to provide a flat surface to act as an anvil for the cam action of the autostop feature. A rounded 10 mm. steel cylinder is pressed into a hole in the lower surface of this bollard, and acts as a wear resisting bar.

The lower bollard is part of an autostop device. The bollard has a projection at the 10-o’clock position, much like that on the later Stop Bobbins; however, the lower bollard is solid aluminum rather than skeletonized steel as on the Petzls. A handle is attached to the bollard with three 6 mm. pins. The handle is covered with a rubberized grip for comfort. The lower bollard and attached handle assembly pivot on the lower 8 mm. rivet. Friction from the main rope’s passage tends to turn the lower bollard and force the cylinder towards the upper bollard, thus locking the rope and ideally arresting the descent. The rappeller uses the handle to keep the autostop feature disengaged.

This bobbin has no markings.

Comments

I have mixed emotions about this bobbin. I do not like painted descenders, but at least the rope-bearing surfaces are unpainted. I think that the solid aluminum lower bollard is superior to Petzl’s skeletonized steel casting.


For far more content, use a larger monitor and a full-width window.

Hundreds of cell phone users complained and asked me to for a simpler, mobile friendly site. In particular, they wanted me to limit each page to a small number of pictures and minimize my use of text. This new site provides what they asked for.