The popular H7 harvester head renewed
The new PONSSE H7 harvester head features a powerful feed and an excellent power-to-weight ratio that improve productivity. Thanks to its improved geometry, the new H7 can process large stems with ease. The advanced PONSSE Active Speed function is a new feature of the H7 harvester head. It allows the speed of the feeding to be adjusted according to the tree species and stem diameter.
Ponsse’s traditional H7 harvester head is one of the most popular in the product line. It is used all over the world for both thinning and clear cutting. Suitable for both hard and soft woods, it is available for all PONSSE harvesters except the PONSSE Beaver.
“The H7 has been in production since the beginning of the 2000s, and it has never received such major updates until now. The H7 is placed between the H6 and H8 in the product line. Before the updates, the H7 was closer to the H6, but now its features are truly halfway between the H6 and the H8,” says Ville Hukkanen, Director of Product Management and PMO at Ponsse.
Easier processing of largers trinks
Although the new H7 cannot handle trunks with a larger diameter than the
previous model, in practice it can now process larger trunks much more
efficiently.
“The shoulder pins of the roller frame have been moved further apart. Thanks to that, the rollers can support the log from below and not just squeeze from the sides. The log now goes more nicely through the harvester head. Since there is less pressure on the knives and rollers, even crooked trees can be handled better,” Hukkanen explains.
The order of the knives has also been changed. While before each of the four knives squeezed the wood from different sides, now the top and bottom knives squeeze the wood from different sides than the two inner knives. Even large trees remain firmly gripped when they are squeezed, with larger intervals between the knives.
“The measuring wheel has a larger diameter, which improves the accuracy of the measurement. The spikes of the measuring wheel remain in contact with the tree for a longer distance, so the traces of the individual spikes are smaller.”
Active Speed improves versatility of the harvester head in processing
The updates to the H7 do not only make it easier to process large trees. For example, the Active Speed function feeds the thick base of the tree through the harvester head more slowly and with greater force. The thinner top, on the other hand, goes through the harvester head faster and with less force. The feed speed changes during sawing, and the operator can adjust it to their liking. This optimises the processing of the entire trunk and also reduces fuel consumption
“Active Speed facilitates both clear cutting and thinning, making it possible to process even small thinning trees quickly with a relatively large harvester head. Active Speed has been a popular feature on the H8, and now it is available on the H7 as well.”
Snow and logging residues out of the harvester hear
The general design of the harvester head has been revised so that snow or logging residues can no longer get packed between the hydraulic cylinders and the body of the harvester head. General serviceability and durability have also been optimised.
“The hydraulics for the front knives is now better protected. The hydraulic cylinders for the knives are all on their own pins, so they are easy to change if necessary. Likewise, all the hydraulic cylinders are now easier to access.”
The connection hoses on the H7 no longer have a feed-through block, but the hoses continue directly from the harvester head to the boom. This way, the hoses no longer have to bend tightly when the tree is felled, and the harvester head is tilted. This saves hoses from wear.
“The new hydraulics also save energy and produce less waste heat. The difference is small, but nevertheless significant enough that it is reflected in fuel consumption.”
Meticulously engineered and tested
The updated H7 harvester head is the result of years of engineering and testing. The starting point has been customer feedback from different parts of the world.
“Our harvester heads are designed as a product family, so many features previously made for larger or smaller harvester heads have now been utilised in the H7, such as the Active Speed feature. The product family approach also allows us to use the same production methods as much as possible and even the same components in different harvester heads, which facilitates spare parts maintenance, for example.”
Production methods have also been refined. For example, the share of robot welding has been increased. The updated production methods save time, materials and the environment, and they usually also improve the quality of the final product.
Customers eagerly anticipate the new H7
The new H7 will replace the old H7 in production in the near future. Customers have been eagerly anticipating the new harvester head.
“The new H7 is interesting, especially the Active Speed function and the new body design,” says Mindaugas Lukas, who was with Remigijus Zdanavicius, Renigijus Lukas, and Algis Zulpa from the Lithuanian company UAB Gerilita at the FinnMETKO trade fair, where the new H7 was presented for the first time at the turn of August and September.
