Patent Application
20210095791
This application claims the benefit of European Application Ser. No. 19199812.9, filed on Sep. 26, 2019, the disclosure of which is hereby expressly incorporated by reference in its entirety.
The present disclosure generally relates to a working vehicle. An embodiment of the present disclosure relates to a timber working vehicle.
Mobile work machines, in particular, forestry equipment and forestry machines, e.g. harvesters and forwarders, have an articulated boom or crane and a tree stem processing tool at the tip of the boom. The crane is used to move the tool and the tree log. Further, the crane provides space for hydraulic lines used to power the tool at the tip of the crane. The tool can be e.g. a harvester head, a felling head, a harvesting and processing head, or a log grapple equipped with a sawing apparatus. The tool can be used e.g. to cut standing trees, to process felled trees or to grab objects, such as logs or tree stems. When using such a tool with power-driven operations, it is operated under the control of an operator of the work machine.
The mobile work machines comprise an articulated crane with the tool attached to a boom tip of the crane. Such tools handle heavy load, that may comprise a load of soil or logs or raw material. Usually such cranes are controlled by hydraulic actuators that are driven by hydraulic pressure from one or more pumps. The pumps are usually powered by the primary power source of the vehicle.
The stem processing tool or harvester tool comprises several movable knives that are used to grab the log/tree with the harvester tool. These knives are hydraulically actuated and controlled by the controller mounted on the harvester tool. Once the tree is grabbed with the harvester tool, a saw blade, usually at a bottom side of the harvester tool, is activated to cut the tree/stem. After the cutting process the tree will fall over, only being fixated in the harvester tool by the knives closed around the stem. Usually, within the harvester tool, feeding wheels are activated to pull/push the stem through the harvester tool and the knives, so that bark/branches are removed, and the log/stem is cut up into log pieces of determined size.
During use the crane continuously works and moves to handle the trees or felled logs or stems. A typical crane usually comprises of multiple connected arms and a jib which holds the tool. The arms are also connected to hydraulic actuators to move the arms relative to each other and to the base working machine. The hydraulic actuators which are also provided in the tool require constant feed with hydraulic power and are thus connected to the hydraulic pump of the vehicle by lines or hoses. The hoses run along the arms and the jib of the crane and have determined linkages via fittings at advantageous maintenance locations where they can be easily inspected and—if necessary—replaced or repaired.
The hydraulic lines or hoses are under a constant strain due to movement of the arms, turning of the crane and the inside hydraulic pressure. Additional strain is applied by high or low temperatures.
The connecting points of hydraulic lines, the fittings are usually held in a fixation on the crane, so that the hydraulic lines have a free length from one connection to the next. Thus, the ability for torque twist is limited by the free length of the hydraulic lines.
U.S. Pat. No. 8,950,538 discloses a fixture in which a hose is held in a movable state, surrounded by a bushing.
On the other side, extending the hydraulic lines lead to a higher maintenance and higher wear on the hydraulic lines.
The present disclosure concerns hose connection system, particular for felling and/or processing logs and a working vehicle with such a system.
It is thus necessary to find a solution which enables work efficient maintenance locations of the fittings, higher torque resistance of the hydraulic lines and easy access of the fittings.
One disclosure is a hose connecting system, which comprises at least two hoses, adapted to be connected to each other, a fitting, adapted to fixedly hold each of the hoses, and realize the fluid connection of the hoses, a holder, adapted to hold the fitting, so that the fitting is able to rotate around a longitudinal axis of the hoses and/or move along a longitudinal axis of the hoses and/or move along an axis orthogonal to the longitudinal axis of the hoses, when the holder holds the fitting.
The hoses are fixed to the fitting and the fitting itself is movably held inside the holder. This enables to have the maintenance locations at the fitting, yet, at the same time to increase the available length of the hoses for twist and lateral movement. Thus, the strain on the hoses connected to the fitting are reduced and increase the lifetime and ability to prevent loosening of the hoses from the fitting.
In a further embodiment, the fitting has a first connection part, adapted to hold a hose, and a second connection part, adapted to hold a hose, and a middle part, connecting the first and second connection part, and wherein the middle part is elongated in the longitudinal direction of the hoses.
The middle part is elongated so that it can be easily inserted in the holder for fixation. The hoses can be crimped to the first and second connection part of the fitting. This allows to separate the middle part being available for movement and twisting inside the holder. The hoses and the crimped areas are well separated from the middle part, increasing the reliability of the fitting and the hose connections.
In another embodiment the cross-section of the middle part of the fitting has a circular shape.
The circular shape allows the free rotation of the middle part inside the holder as well as minor axial movement in the longitudinal direction of the hoses to compensate length changes of the hoses due to movement or twisting.
In a further embodiment the cross section of the middle part of the fitting has a rectangular shape.
The rectangular shape allows lateral movement when the holder provides a long hole to facilitate that movement. In such a case the fitting can move sideways, that is along an axis orthogonal to the longitudinal axis of the hoses. A twisting movement is prevented, but the sideways movement can be used to compensate for movement of the hoses.
In another embodiment the holder is adapted to be fitted to a crane.
The use of the holder and the hose connecting system on a crane, preferably on a working vehicle leads to a longer lifetime of the hoses and improved maintenance locations.
In a further embodiment the holder comprises of a base part and a cover part.
The base part can be fixed to any surface, such as a crane arm, wherein the hose is held in place between the base part and the cover part, which is removably fixed to the base part.
In another embodiment the hose connecting system comprises an additional bushing, adapted to be placed between the fitting and the holder, so that the bushing acts as a bearing element.
The bushing along the middle part enables to reduce friction between the middle part and the holder so that twisting linear movement are further supported. This also leads to less wear of the parts involved and further reduces the strain on the hoses.
In a further embodiment the system comprises at least a bearing between the fitting and the holder.
The bearing further reduces frictional forces between the middle part and the holder.
In another embodiment the bushing comprises PTFE.
PTFE reduces the frictional forces between the middle part and the holder and can offer a sealing function.
In a further embodiment the fitting and the holder are adapted to limit the translational movement in the longitudinal direction within the holder.
The first and second connection part of the fitting can have a greater diameter that the holder. Thus, the first and second connection part will work as an end stop, when the middle part is fixed by the holder, limiting the axial travel. This can be used to limit strain on the hoses during movement.
Another disclosure is a hydraulic crane for a working vehicle comprising a hose connecting system, which further comprises at least two hoses, adapted to be connected to each other, a fitting, adapted to fixedly hold each of the hoses, a holder, adapted to hold the fitting, so that the fitting is able to rotate around a longitudinal axis and/or move along a longitudinal axis and/or move along an axis orthogonal to the longitudinal axis, when the holder holds the fitting.
The hoses are fixed to the fitting and the fitting itself is movably held inside the holder. This enables to have the maintenance locations at the fitting, yet, at the same time to increase the available length of the hoses for twist and lateral movement. Thus, the strain on the hoses connected to the fitting are reduced and increase the lifetime and ability to prevent loosening of the hoses from the fitting. The use of the holder and the hose connecting system on a crane, preferably on a working vehicle leads to a longer lifetime of the hoses and improved maintenance locations.
The disclosure is further described in
In
The fitting with the connected hoses 110, 120 is then placed inside a holder 140 which has openings in circular shape. As the fittings middle part 133 also is provided with a round shape, both parts can glide easily and thus the fitting with the hoses 110, 120 is able to rotate inside the holder base part 141 and the cover part 142. The cover part 142 is preferably fixed with screws to the base part 141, yet, also other designs are possible, such as a riveting fixation or straps. In the fixed or closed holder state, the fitting is able to undergo twisting movement in the supported state. When the working machine is moving and the hydraulic hoses 110, 120 are moved, e.g. bend, twisted, elongated, the fitting can move to a certain degree in the lengthwise direction of the hoses 110, 120 but most importantly can twist together with the hoses 110, 120 so that the twistable length of one hose is extended to include the connected hose. This reduces the torque applied on the hoses and increases lifetime and durability of the hose-fitting-hose connection. It is also superior to a single hose, as the fitting connection allows for shorter hoses and better maintenance and exchangeability of the components.
In another version the middle part 133 of the fitting may be covered by an additional bushing 150 which can serve as a bearing surface between the holder 140 surface and the middle part 133. This further reduces friction and facilitates the twisting and elongation motion.
In case the holder 140 has an elongated hole for the fitting in an orthogonal direction B of the axis A, the holder 140 also enables the fitting to have a sideways movement, further reducing strain on the hoses 110, 120 during use.
Also, the holder 140 can have a rectangular opening, as well as the middle part 133 of the fitting having a rectangular cross section. The middle part 133 can slide in a lengthwise direction by limiting any twist movement. This can be advantageous if any twisting movement of the hoses 110, 120 is not occurring, but a larger axial lengthwise movement is expected.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19199812.9 | Sep 2019 | EP | regional |
