초록 ▼

A hydraulic linkage which is usable as a front loader on an agricultural or other tractor (1) comprises at least one jib, and usually two interconnected jibs (5, 6, 9) which jibs are upwardly and downwardly turnable about an axis (3) relative to frame means (2). Each jib (5, 6, 9) comprises telescop

A hydraulic linkage which is usable as a front loader on an agricultural or other tractor (1) comprises at least one jib, and usually two interconnected jibs (5, 6, 9) which jibs are upwardly and downwardly turnable about an axis (3) relative to frame means (2). Each jib (5, 6, 9) comprises telescopic firt (5) and second (6) portions and the second portions (6) are extendible from the first portions (5) during raising of the jibs so that a load/apparatus carried at the outer end (9) of each second portion (6) is raised substantially vertically, rather than arcuately about said axis (3). Spring (44) operated lost-motion mechanism prevents such extension during a lower arc of movement of the jibs (5, 6, 9) about said axis (3). Raising and lowering is effected by hydraulic rams (13) which preferably have chambers constantly linked by ducts (26) to chambers of second hydraulic rams (17) in such a way that any load/apparatus can automatically be maintained in a chosen attitude to the horizontal during raising or lowering of the jibs (5, 6, 9). The linkage provides improved stability, a substantially constant length of forward reach, improved vertical reach and the facility for automatic self-levelling of loads/apparatuses which are carried thereby.

대표청구항 ▼

An improved linkage assembly comprising frame means attachable to a vehicle, said linkage including at least one loading jib of variable length that is turnable upwardly and downwardly relative to the frame means, means adapted to act on said jib for increasing the length of said jib during raising

An improved linkage assembly comprising frame means attachable to a vehicle, said linkage including at least one loading jib of variable length that is turnable upwardly and downwardly relative to the frame means, means adapted to act on said jib for increasing the length of said jib during raising thereof and for decreasing the length of the jib as it is subsequently lowered, a lost-motion connection for rendering said means inoperative throughout a predetermined lower portion of the path of upward and downward turning movement of the jib, wherein: said jib is maintained in a minimum length position throughout said predetermined lower portion of the path of upward and downward turning movement thereof by a pair of plates that are pivotally connected to a first jib portion, said plates also being pivotally coupled to a second jib portion and to said frame means by way of said lost-motion connection so that, upon raising the jib from a lowered position, said lost-motion connection prevents pivotal movement of said pair of plates until a predetermined inclination of the jib to the horizontal has been attained and whereafter, said pair of plates is caused to pivot relative to the first jib portion, the pivotal movement thereof being employed to cause length-increasing displacement of the second jib portion relative to the first jib portion.