Hitch Climber Pulley

For the past two decades, DMM has been working closely with Chris Cowell, Mark Bridge and Bernd ‘Beddes’ Strasser, practicing arborists and founding members of Treemagineers, to design, develop and create new products to suit specialist industrial and tree care environments.

The first product to result from the close innovative cooperation between DMM and Treemagineers was the Triple Attachment Pulley (TAP)—a core component of the Hitch Climber system.

For Mark and Chris, the idea for a new pulley system began, not with a conversation about equipment, but a conversation about techniques whilst working together in trees.

Mark Bridge explains: “Before the invention of the Triple Attachment Pulley, the way work positioning took place on tree care was very cluttered. We were having to jury rig using the largest HMS connectors we could get, jamming pulleys with bits of rope and slings.”

“Specifically, we took a closer look at connectors and the ways they were being used in tree care. By examining the profiles of cross sections and considering load configurations, we were able to analyse the strongest parts of the system. In doing so, we realised that what we were trying to accomplish was completely counter intuitive.”

“In a moving rope system, you have two legs of rope that pass over the top anchor point and come back down again, with half body load on each leg,” explains Mark.

“The termination was sitting right on the outside towards the nose of the carabiner, so we had the highest load attached to the weakest point of the connector. It was then that we realised that a technical fix wouldn’t work. We needed an equipment fix.”

“Working with a development engineer, we eventually came up with some elaborate concepts that ticked all the boxes. However, it quickly became apparent that the end product was niche and therefore not viable.”

“When we came to DMM in 2004, one of the things we focused on was the way the line ran into the device. We wanted the rope to be encouraged to be fair when approaching from awkward angles.”

The first iteration of the product had a two hole pulley with a small attachment hole in the middle for an accessory cord or locking bolt to fix the two side plates against rotation. By splitting the attachment to the climber into two carabiners, this mitigated some of the problems outlined.

“When Chris brought the concept of the third hole to the table,” says Mark, “the expectations for what the product could achieve suddenly multiplied.”

He continues: “Where we had previously focussed on complexity, this third hole opened up options. In one stroke, we had addressed all the issues we were attempting to overcome: the cluttered configuration, the miss-loading of connectors, the wide loading on the top end of the carabiner and the nose loading. The possibility of the third attachment hole allowed us to organise equipment efficiently and also solve compatibility issues between connectors.”

This combination of the third hole and the flares led to the first version of the Triple Attachment Pulley.

The Triple Attachment Pulley was first showcased in 2006 at the International Tree Climbing Competition (ITCC), Indianapolis. Presenting the pulley at the competition was Bernd Strasser – having won the ITCC nine times, he is one of the most accomplished tree climbers in the world.

An elite performer together with the possibilities presented by this new gear led to a huge success at the competition and paved the way for a new style of pulley.

With the joint objectives of improving safety and efficiency in professional tree care, the pulley first demonstrated at the ITCC outlined new ways for the industry to think about work positioning equipment. Its hot forged silhouette became instantly recognisable.

The team have taken another step forwards with the new Hitch Climber Eccentric pulley that has evolved from the original TAP. “We finally have the flares we always wanted in the original concept,” says Mark, “and let’s not forget – it looks good too.”

The improvements result from over a decade of Hitch Climber design and manufacturing expertise, together with feedback from climbers. By adopting a non-symmetrical design, DMM have been able to differentiate the rope channel between the top and bottom. Also, the elongated shape of the body with a pushing surface at the upper end that interfaces with the lower part of the friction hitch improves hitch function, while the optimised fairlead flairs direct the rope towards the sheave when tending slack.

Like so many of the products developed at DMM, The Triple Attachment Pulley and the new Hitch Climber Eccentric are the outcome of a team effort.

According to Fred Hall, DMM’s Technical Director and Chairman: “We put as much effort into making as we do design. It’s not just about inventors and designers—our products are inspired by the people who assemble them and the individuals who use them. When people bring us their ideas, we like to see if we can bring these ideas to life.”

“The way people manufacture dictates what their products look like,” says Mark. “It wouldn’t have been possible to create the pulley without the forging skills that DMM possess, and the willingness to embark on this journey with us. We have ended up with a product that has relevance and is a valuable contribution to the industry of tree care and tree climbing.”

As Mark points out, it is hard to overstate the relevance of this product to the tree care industry. Working with advanced manufacturing techniques and high-performance materials to create bespoke tree care products, this landmark pulley brought to the forefront the importance of configuration and compatibility in everyday tree care.

The new concept of the triple attachment hole provided a platform on which to build and develop, offering more possibilities for the average tree climber to evolve their skills.

To this day, the Triple Attachment Pulley remains an iconic design. Its longevity is testament to its success in meeting its original objectives; namely a well configured foundation upon which friction hitch based climbing systems could be evolved.

Primarily developed with moving rope systems in mind, the TAP has also been adopted at the core of stationary rope systems that incorporate friction hitches.