False Bobbins

Bobbins are mechanical descenders where the rope path follows the S-shaped path shown in the figure. In general the braking surface consists of two non-rotating bollards fixed to a sideplate, with a second pivoting sideplate provided to keep the rope from jumping off the other end of the bollards. A third (usually smaller) bollard may be provided. The seat maillon usually attaches to holes in extensions of the two sideplates; these holes are aligned when the sideplates pivot to the closed position.

I distinguish true bobbins from false bobbins by whether the spools (or bollards) move with respect to the frame. On true bobbins the center of the spools is fixed although the spools may rotate (on stop bobbins, the lower one usually does). On false bobbins, the center of the spools can move. I don't believe that there is necessarily any advantage of true bobbins over false bobbins or vice versa, it's merely a means of classification. All of my false bobbins are "stop" bobbins.

The Single Rope Technique bobbins are well made, but I find them to be tiring. If you try these and pay attention, you may notice that squeezing the handle actually lifts you. The Antec and Anthron work on a different pincipal, and do not have this problem. The Single Rope Technique bobbins are also heavy, due to their steel parts. The Butkovic is an old design that may never have been commercialized, but I find it to be most interesting.

ID	Device	Description	Acquired	Weight	Height	Width	Thickness	Std. volume
546	Antec Double Stop	Fixed frame, bobbins pivot on lower rivet, handle pivots on upper rivet	Innner Mountain Outfitters, 1999	348	190	84	26	415
1152	Anthron DSD 30+25	Fixed frame, bobbins pivot on lower rivet, handle pivots on upper rivet	Bret Auernig, 2008	334	191	79	27	404
978	Butkovic Clone	Two piece, fixed lower and auxiliary bollard on frame, sliding upper bollard on handle	Dr. Gary D. Storrick, 2004	519	220	86	39	729
950	Single Rope Technique Two-way Rescue Stop 2WRS	Fixed frame, bobbins pivot on middle rivet, handle pivots on upper rivet, rope guide pivots on lower rivet	On Rope, 2004	553	205	73	40	602
1023	Single Rope Technique D1, Version A	Steel double-rope bobbin & handle assembly, guide bar, stamped gate, holes for no-stop carabiner.	Tom Vines, 2006	407	220	73	36	573
445	Single Rope Technique D1, Version B	Steel bobbin & handle assembly, guide bar, stamped gate, no-stop carabiner hole.	Inner Mountain Outfitters, 1988	407	225	75	35	591
519	Single Rope Technique D1a	Steel bobbins & handle assembly, two guide bars, stamped gate, hole for no-stop pin.	Inner Mountain Outfitters, 1996	467	227	79	37	664
446	Single Rope Technique D1DB	Steel bobbin & handle assembly, guide bar, stamped gate, double brake, no-stop pin & hole.	Single Rope Technique, 1989	523	245	98	41	984
447	Single Rope Technique D2, Version A	Steel double-rope bobbin & handle assembly, guide bar, stamped gate, holes for no-stop carabiner.	Raven Products, 1990	498	222	73	46	745
448	Single Rope Technique D2, Version B	Steel double-rope bobbin & handle assembly, guide bar, stamped gate,stamped gate, no-stop pin & holes.	Single Rope Technique, 1989	509	222	73	46	745
1111	Single Rope Technique DS1	Steel bobbin & handle assembly, steel frame, guide bar, stamped gate, no-stop pin hole.	Richard Wolfe, 2007	711	226	75	37	623
449	Single Rope Technique D2DB	Steel double-rope bobbin & handle assembly, guide bar, double brake, holes for no-stop pin.	John E. Weinel, Inc., 1989	631	245	98	52	1249
573	Single Rope Technique RS1a	Steel bobbins & handle assembly, long braking arm, stamped gate, hole for no-stop pin.	Single Rope Technique, 2000	716	227	84	43	815
574	Single Rope Technique RS2a	Steel bobbins & handle assembly, short braking arm, stamped gate, hole for no-stop pin.	Single Rope Technique, 2000	654	227	83	43	808
575	Single Rope Technique RS6DBS	Steel frame, steel double-rope bobbin & handle assembly, rotating lower bollard, two guide bars, oversqueeze brake, stamped gate, holes for no-stop pin.	Single Rope Technique, 2000	1058	249	114	50	1431