Valentini have developed a carriage for full load suspension without the help of a diesel engine.
The carriage was developed within the scope of the European project INFRES. With the new carriage, the lift line is powered by the mainline, which wraps around a dedicated parabolic capstan co-axial with the lift line drum. The mainline then exits the capstan and connects to the haulback line, to form a closed loop. By reeling in the haulback line on the yarder winch, the lift line spools out. When the mainline is reeled in on the yarder winch; the lift line spools in, which lifts the load. The uniqueness of the Valentini carriage is that the lift line drum can be disconnected from the capstan and braked, so that it is possible to operate two identical carriages in tandem. By alternately braking and disconnecting the two lift line drums, one can use the lift lines independently.
The carriage has 4 hydraulic valves. They are used to activate the swing in and out of the hydraulic clamp mount, closing or opening the hydraulic clamp, connecting or disconnecting the lift line drum to the parabolic sheave, and engaging or disengaging the lift line drum ratchet block. Hydraulic pressure is provided by a standard accumulator, which is kept charged by an electrically operated hydraulic pump. An alternator is connected to the skyline rollers through a gear reduction, so that the compact battery built into the carriage is kept charged. As the carriage travels on the skyline, the alternator accumulates energy into the battery, which keeps the hydraulic accumulator loaded. This way, one obtains double energy accumulation in the battery and in the hydraulic accumulator. This allows complex manoeuvring without running out of hydraulic pressure, even when the carriage is working on short distances. All actual work (lifting and travelling) is done through the yarder winches, so that the power sources in the carriage are kept to the minimum necessary for the braking/releasing and connecting/disconnecting of the work gear.
Compared to a motorised carriage, the new tandem carriage is 40% lighter and 33% cheaper to purchase. Also, by removing the on-board diesel engine, overall fuel consumption is reduced by 20%. These improvements are likely to increase the viability of biomass recovery and the general financial and environmental sustainability of the harvesting operation.
One can also use the two carriage elements separately to replace a traditional self-clamping carriage, which would result in reduced mainline wear. Standard self-clamping carriages use the winch mainline to lift their loads, which results in accelerated wear of the lift end of the mainline. As a result, operators have to cut the worn end of the mainline at regular intervals, in the order of one or two weeks, depending on use intensity. By doing so, they end up making the mainline too short, which leads to premature replacement the moment they have to tackle a long distance job and they lack enough mainline length. Source: http://www.valentini-export.com/?lang=en#undefined