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I don't have a record of when or where I acquired this descender, but I believe it was around 1990.
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 the cylinder attached to the Diablo. 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 grove 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.
This is a copy of the Petzl Stop, Version A, yet executed well enough to trust in practical use.
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I acquired this descender from Theresa Williams and Maury Benamy in 1995.
The side plates and handle are stamped from 3 mm. aluminum.The pivoting side plate has a spring wire gate that allows one to rig the bobbin without unclipping from the seat harness.
The upper main 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 8 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. A handle is attached to the bollard with two 4 mm. screws. The fixed side plate prevents these screws from backing out. The handle portion is bent into a U to increase thickness, then covered with a plastic grip for comfort. A 13.5 mm. diameter cylinder is attached at the 10 o'clock position with a 4 mm. screw through the handle plate (much like that on the Diablo).The lower bollard and attached handle assembly pivot on the lower 7 mm. bolt. 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 features the auxiliary bollard seen on the later Petzl Bobbins and Petzl Stop Bobbins.
The bobbin has a sticker on the rear with a logo, some Cyrillic text that I cannot reproduce here, and "Tested." The logo is stamped at the top of the pivoting side plate.
The spring wire gate latch is an improvement over the gates on most bobbins. It works quite well, I would like to see more of these.
The auxiliary bollard works very well for keeping the rope on the upper main bollard without binding, but is less satisfactory when used as part of the braking system. The rod is too small to function well as a third braking surface, has no means to insure that the rope stays on the rod reliably, and is located where it forces the rope into an inconvenient position. This last point is particularly noticeable if the trailing rope passes through a maillon clipped to the seat maillon as indicated in the Petzl instructions and required for safety. In this case it requires too many contortions to switch from the two bollard mode to the three bollard mode.
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I acquired this descender from Serguei Khramtsov (from Ural Sport), who did some shopping in Russia for me in late 2004.
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.
The bobbin has no markings.
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.
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©2007, Gary D. Storrick