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. Stop bobbins have a mechanism that applies additional braking force if the rappeller releases or squeezes (depending on the design) a handle on the bobbin. Sometimes the additional friction is enough to stop the rappeller, which possibly transforms the resulting injury from impact trauma to harness suspension trauma.
I find that the Petzl
Stop is more likely to stop me than the Diablo,
Dressler or Kong
- in fact, on a clean rope, I can often rappel with these locked
off. The Petzl I'D is
a complex device that I've included here after trying it and seeing
that the rope follows a bobbin "S" instead of the odd
path shown in the instructions. The Tracson
is another complex device that I've included here rather than
create a new category. It combines a Jumar-type
cam with a bobbin into a single rappel and ascent device. I would
not like to rely on the stop feature because of the sharp cam
teeth. My Tracson bent
each of the first two times I tested it, so I haven't used it
since. Its an interesting idea, but I think it needs more work
to be practical.
[ Additional Comments on Bobbins ]
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| ID | Device | Description | Acquired | Weight | Height | Width | Thickness | Std. volume |
|---|---|---|---|---|---|---|---|---|
| 431 | BO.VE Diablo | Bent frame, solid spools, round brake, no-stop lock, stamped gate | Repetto Sport, 1982 | 327 | 223 | 63 | 32 | 450 |
| 432 | Dressler DAD | Bent frame, irregular cast spools, open top | Repetto Sport, 1982 | 247 | 179 | 51 | 32 | 292 |
| 1168 | heightec-PMI Powerlock | SS Frame, Al spring-loaded upper spool, cast SS lower spool on handle /w red plastic grip | On Rope 1, 2008 | 737 | 162 | 184 | 30 | 878 |
| 1169 | heightec-PMI Quadra | SS frame /w openings, Al upper spool, cast SS lower spool on spring-loaded plate /e spring/loaded Al handle | On Rope 1, 2008 | 692 | 185 | 92 | 30 | 507 |
| 522 | Kong | Bent frame, solid spools, cut lower spool, top brake linked to handle, stamped gate | Inner Mountain Outfitters, 1996 | 397 | 230 | 65 | 32 | 478 |
| 433 | Kong-Bonaiti | Bent frame pivots at top bar, solid spools, cut lower spool, top brake linked to handle, stamped gate | Speleoshoppe, 1982 | 400 | 239 | 60 | 30 | 430 |
| 903 | Kong Indy | Bent frame, solid spools, cut lower spool reversed, top brake linked to handle, stamped gate | Inner Mountain Outfitters, 2001 | 476 | 230 | 64 | 31 | 456 |
| 565 | Petzl I'D. Large, Version A | Irregular bollard /w handle & integral clutch, anti-error catch, swinging face plate | Inner Mountain Outfitters, 2000 | 526 | 194 | 83 | 54 | 870 |
| 1166 | Petzl I'D. Large, Version B | Irregular bollard /w handle & integral clutch, anti-error catch, swinging face plate | Rescue Response Gear Inc., 2008 | 525 | 203 | 79 | 52 | 840 |
| 1218 | Petzl I'D. Large, Version C | Irregular bollard /w handle & integral clutch, anti-error catch, swinging face plate, horizontal mode button | On Rope 1, 2009 | 550 | 212 | 80 | 54 | 912 |
| 556 | Petzl I'D, Small, Version A | Irregular bollard /w handle & integral clutch, anti-error catch, swinging face plate | Inner Mountain Outfitters, 1999 | 536 | 194 | 83 | 54 | 870 |
| 1219 | Petzl I'D, Small, Version B | Irregular bollard /w handle & integral clutch, anti-error catch, swinging face plate, horizontal mode button | On Rope 1, 2009 | 558 | 212 | 80 | 54 | 912 |
| 435 | Petzl Stop, Version A | Bent frame, solid upper (cut) & lower (/w steel brake) spools, stamped gate | Repetto Sport, 1982 | 289 | 225 | 61 | 33 | 453 |
| 436 | Petzl Stop, Version B | Bent frame, solid upper (cut) & lower (/w steel brake) spools, stamped gate | Caves Unlimited, 1984 | 302 | 226 | 64 | 32 | 463 |
| 437 | Petzl Stop, Version C | Stamped frame, solid upper spool (cut), cast lower spool /w stop, aux. rod, stamped gate | John E. Weinel, Inc., ~1987 | 327 | 240 | 63 | 32 | 484 |
| 438 | Petzl Stop, Version D | Stamped frame, solid upper spool (cut), cast ribbed lower spool /w stop, aux. rod, stamped gate | Bob & Bob, 1991 | 322 | 225 | 62 | 32 | 446 |
| 541 | Petzl Stop, Version E | Stamped frame, solid upper spool (cut), cast ribbed lower spool /w stop, aux. rod, plastic gate | TSA, 1997 | 325 | 223 | 68 | 32 | 485 |
| 451 | Russian, Version A | Bent frame, solid upper spool (cut), solid lower, stamped gate | Theresa Williams/Maury Benamy, 1995 | 255 | 220 | 62 | 27 | 368 |
| 518 | Russian, Version B | Bent frame, solid upper spool (cut), solid lower spool /w round stop, aux. rod, wire gate | ? | 246 | 222 | 55 | 32 | 391 |
| 973 | Russian, Version C | Bent frame, solid upper spool (cut), solid lower, aux. rod, stamped gate | Ural Sport, 2004 | 286 | 208 | 74 | 30 | 459 |
| 1013 | SAR Scarab, Version A | Bent frame, solid upper spool, solid lower spool (cut), lever /w round stop, stamped gate | SAR, 2006 | 436 | 195 | 62 | 35 | 419 |
| 1029 | SAR Scarab, Version B | Bent frame, solid upper spool, solid lower spool (cut), lever /w round stop, stamped gate | SAR, 2007 | 430 | 195 | 62 | 35 | 419 |
| 1211 | SAR SARAB | Bent frame, solid upper spool, solid lower spool (cut), spring-loaded lever /w folding handle & round stop, stamped gate | SAR, 2009 | 470 | 206 | 65 | 35 | 472 |
| 1215 | SMC Spider | Milled body, SS cover plate, rear handle | On Rope 1, 2009 | 554 | 214 | 85 | 41 | 739 |
| 452 | Voynett S.A.R.L. Tracson | Combination bobbin and ascender | Repetto Sport, 1982 | 580 | 192 | 107 | 50 | 1027 |

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