Front	Rear
Left Side	Right Side
Front: Open for Rigging	Rear: Open for Rigging

Technical Details

I acquired my first Pro Allp Tech from Dalloz Fall Protection in September 2000, and a second one from Paul Hugill in 2007. The Pro Allp Tech is an updated model of the Troll Alp.

The Pro Allp Tech consists of four bollards, mounted between two side plates that pivot on a fifth attachment post. The #2 bollard has an integral braking nose. This bollard naturally rotates so that the nose stops the rappel. An autolock handle controls the cam so that one can descend. A screw control assembly helps vary the friction in the device.

Each side plate is a roughly triangular piece of red anodized 1/8-in (4.2 mm.) 7075-T6 aluminum. The plates are 145 mm. high with a curved top and sides, with various cutouts in the sides. Each plate is 69 mm. wide at the top and tapers in an irregular manner to join a 22 mm. diameter circular arc at the bottom. The side plates are attached to a 17.5 mm. diameter grooved stainless-steel attachment post at the center of the bottom circular arc. The rear plate is tightly bolted to the post, while the front plate is loosely bolted so that it can rotate open. A spring acts to close the front plate. The front plate has a large aluminum logo plate mounted on the top front. The distance between the side plates is 15 mm.

The #3 and #4 bollards are bolted to the front plate with torx socket round-head bolts. The #1 bollard is also fixed to the front plate, but the logo plate covers the attachment bolt. The rope runs around the #1 and #3 bollard, while the #4 bollard is a passive rope guide. These bollards do not rotate, but there are no visible pins preventing the rotation. The bollards are stainless steel. The #1 and #3 bollards each have a groove that fits into a corresponding notch in the rear side plate. The #4 bollard is shorter and does not extend into the rear plate. The #1 bollard diameter is 12.5 mm in the center, and widens to 16.2 mm. about 1 mm. from the side plate, then remains constant. The #3 bollard has similar dimensions, while the corresponding diameters for the #4 bollard are 10 mm. and 12.8 mm., respectively.

The #2 bollard is not circular. Viewed from the front, there is a rope groove from the 2-o’clock position counter-clockwise to 2-o’clock. The radius at the center of rope groove is about 13.8 mm. at 2-o’clock, increases to 17.3 mm. at 11-o’clock, decreases to 15 mm. at 7-o’clock, then increases to 15.2 mm. at 6-o’clock. The braking nose is at 4-o’clock and has a radius of 17.7 mm. The #2 bollard can rotate through about 30°; the rotation is limited by a roll pin that moves in a slot milled in the rear plate. A hidden spring (assisted by rope friction) rotates the #2 bollard clockwise so that the nose presses the rope into the #3 bollard to increase friction. A spring-loaded autolock handle mounted on the #2 bollard swings to the 8-o’clock position without action, then begins to turn the #2 bollard to decrease friction.

The four bollards are mounted 118 mm., 61.5 mm., 42 mm. and 86.5 mm. from the center of the pivot point. When the rope is inserted, this asymmetrical arrangement ensures that the rope is pinched between the #2 and #3 bollards only.

The rear plate has an aluminum block riveted (four rivets) to the upper left inside of the plate. A 10 mm. threaded rod (with about 11 left-hand threads per centimeter) passes through this plate and presses against the upper bollard. A milled cross piece is pinned to the other end of the rod, making it much like a wing nut. Turning the nut extends the rod so that it pushes against the top bollard. This causes the front plate to open, and increases the distance between the #2 bollard and the#3 bollards, thereby decreasing friction (the rope is squeezed less). There is a spring-loaded pin (spring lock) mounted on the back of the block. The pin extends through the rear plate to a knurled knob. The other end engages a slot in the front plate. Pulling in the knurled knob the pin allows one to open the Pro Allp Tech.

The front plate has two illustrations: a rigging illustration and an arc with double arrowheads plus open and closed locks indicating how to use the autolock lever. The front plate also bears the text "PAT No. 2256673," "CE 0120" and "EN12841C." The logo plate is stamped with "Pro Allp Tech" (with Allp being stylized) and "Troll" in an ellipse. The rear plate is stamped "00101" (the serial number). The ends of the wing nut are painted to indicate which direction to turn: a white open lock on a green background to open (decreasing friction), and a white closed lock on a red background to close (increasing friction). The block is marked in the same manner, and is also stamped with two arrows to indicate which way to turn the nut.

Comments

The Pro Allp Tech is beautifully made - I've seen very few rappel devices that are so nicely manufactured. My photographs don't do the Pro Allp Tech justice - the flash greatly exaggerates unevenness in the finish, to the naked eye this is barely noticeable. There are no sharp edges on the Pro Allp Tech - everything is nicely rounded.

The instructions state that the Pro Allp Tech was tested to prEN12841 using new Troll 11 mm. x 32 Platt Rescue and Intervention rope and Cousin 10.5 mm., 11 mm. x 16 Platt and 12.5 mm. x 20 Platt low stretch ropes. low stretch nylon rope. None of these ropes were readily available here, but the Pro Allp Tech seems to function quite well on common caving and climbing ropes in the 9 mm. to 13 mm. size range. Obviously, it is faster on smaller ropes. When the rod is unscrewed, there is enough friction to hold me in place on all of these ropes. As the rod is tightened, the friction is gradually reduced. The transition is slow enough that it is easy to maintain control with the braking hand. The rod turns easily, without any sensation of having to force it. This time there was no surprise, after using the Troll (USA) Alp I expected the Pro Allp Tech to work well, and it does.

Getting used to the left-hand thread was no problem. The Pro Allp Tech is designed for the traditional right-handed user who brakes with their right hand at the right hip. Although I'm right-handed, I prefer to brake left-handed, so I’d rather have a mirror-image version, although this hardly is significant enough to be worth worrying about.

One should understand that part of the friction is obtained by squeezing the rope between the center and bottom bollard. As one turns the rod counter-clockwise, it forces the rear plate in the direction that separates the center and lower bollard, reducing the rope squeezing action. The friction decreases accordingly. This process only continues until there is no more squeezing. After that, there is very little change in friction. This is rather obvious, because there is no large change in the snubbing angle once the bollards are separated. The practical effect is that if one starts a rappel with the rod screwed in and finds out that the friction is insufficient, it will take many turns before the friction is significantly increased. One should always start with the rod unscrewed as far as practicable for the conditions. The autolock lever should not be used to control friction, instead, open in the entire way to descend. If the rappel is not fast enough, release the autolock lever and stop, then adjust the wing nut with the same hand. This way there is no temptation to remove the braking hand from the rope.

The instruction sheet shows how to use the Pro Allp Tech as a secondary (emergency?) ascender. I wouldn't want to try this, not because it wouldn't work, but because it would be too much work compared to simpler options.

The Pro Allp Tech has an almost ideal shape for packing, and it doesn't even have the rod to get in the way like the Troll Allp has.

I'm quite impressed by the Pro Allp Tech, and for its intended use, it deserves two stars: