A unique knuckle-boom crane installed with a felling grapple—named Treezilla by manufacturer Timberland Truck Sales—utilizes a Straightpoint (SP) load pin to record the weight of branches as they are cut from trees.
As in this case, SP’s load pins are commonly custom designed for specialist applications where an end of line load cell cannot be used or an integrated solution is required in applications such as pulley or sheave axles, moorings, and winches. A load measuring pin senses the force applied across it via strain gauges installed within a small bore through the centre of the pin.
Jack Lippett, president at Timberland, said: “The load pin and transmitter were specifically designed to be used with many common hydraulic rotators with a twin ear top plate. The load pin is manufactured to rest on the notch of the rotator to prevent the pin rotating out of position. This unique design is easily transferable between different manufacturer rotators. It eliminates having to custom design the crane attachment end of a hanger load cell. It is highly accurate and rugged to work in the demanding logging environment.”
The Treezilla pin, which feeds data to an SP Handheld plus display unit, is being marketed in the U.S. through ICM Equipment NA Corp., the North American representative of International Construction Machinery (ICM). Complete with a custom steel cover that protects it from damage by either falling debris or other impact, manufactured for ICM-NA, the load pin transmitter has been tested to 152m (500 ft.) range—more than adequate for the operator to retain clear vision but stay in the “safe zone”.
Timberland has entered into a partnership with loader crane manufacturer Hiab to develop the Treezilla prototype and three further models. Timberland currently builds smaller knuckle-boom trucks with a combination of log / chip dump bodies that include a log grapple for the arborist industry, suited to landscaping and tree removal applications. These trucks provided the basic concept for the larger version with increased size, reach, technology, and other capabilities.
The first Treezilla boom was mounted on a 2018 Freightliner 114SD Truck with 430 horsepower, 20,000-lbs. front axle, 46,000-lbs. rear axle, and double lock rear. Timberland installed a Hiab 435K boom with a felling grapple end attachment that can reach 28m (92 ft.) cutting height and boasts a lifting capacity of 280,300 ft. / lbs. The grapple is capable of hydraulically tilting itself into a vertical position to grab and cut a tree limb or trunk; it is equipped with a hydraulic saw with a 20-in. diameter cutter.
Jessica Lippett-Adams, office manager at Timberland, said: “By using a felling grapple the operator can safely remove portions of a tree or the whole tree from a distance. This helps to greatly reduce the risk of injury to the operator or damage to property. The portion of the cut tree is under the operator's control. The crane is more stable then other cranes of its size, which allows for greater control when the system takes on the load of the cut pieces.”
Treezilla and the load pin were recently showcased in collaboration with Skyline Tree Service, which accepted a scope of work to remove a large tree, showing signs of rot, from a cemetery. Lippett-Adams explained that the work area was an old burial section featuring irreplaceable head stones over 100 years old. Further, the tree was structurally weak and Treezilla facilitated careful dismantling, without causing any damage.
“By knowing the weight of the load, the crew was able to work efficiently and safely around the delicate property,” she added.