DUPLICATE LAYOUT OF CONTROL LEVER SETS OF A DISTRIBUTOR OF HYDRAULIC EQUIPMENT FOR TRUCKS, PARTICULARLY HYDRAULIC CRANES

Technical field

The present invention relates to a duplicate layout of control lever sets of a distributor of hydraulic equipment for trucks, particularly hydraulic cranes.

Background of the Invention

It is known that the different functions of hydraulic cranes and more generally of generic hydraulic equipment installed on trucks are activated selectively by means of a multiway distributor which is controlled by means of at least one set of control levers arranged to the side of the truck in a position which can be accessed by the operator.

It is well-known that the control lever set is usually duplicated on both sides of the truck, so as to allow to control the crane or the like even when one side of said truck cannot be accessed.

In the duplicate provision of the control lever sets there is the problem of maintaining the sequential arrangement of the levers, so as to avoid causing the operator to experience difficulties or uncertainties in control when passing from one side of the truck to the other.

Thus, for example, if a set of five control levers arranged side by side on the right side of the truck has an axial sequential layout (where "axial" designates an arrangement which extends along the direction of the longitudinal axis of the truck) for example from left to right or viceversa, the same set of levers, duplicated on the left side of the truck, must have the same sequence from left to right or viceversa.

This condition clearly entails reversing the controls, in that the lever arranged at the far left of the set of levers on the right side must-coincide, in terms of control applied to the distributor, with the lever arranged at the far right of the set of levers of the left side and viceversa. In this manner, the operator always finds the same sequence of levers, for example from left to right or viceversa, both for the set installed on one side and for the set arranged on the other side of the truck.

For instance, GB-2,116,937A discloses a dual control arrangement for vehicular cranes comprises two control units placed at opposite sides of a vehicle, each unit comprising a plurality of manually actuated control members arranged to actuate a corresponding number of valves determining the functions of the crane.

For this purpose, FR-2,523,544 already discloses a duplicate layout of axial sets of control levers in which the levers of one set are kinematically connected to the corresponding levers of the other set by means of a bundle of transmission rods which physically cross each other at the central longitudinal plane of the truck.

However, this conventional layout has failed to yield satisfactory results because it is too complicated, it is subject to frequent jamming and requires continuous and accurate maintenance.

In order to obviate these drawbacks, an alternative transverse layout has been proposed and provided in which the levers of the control sets are arranged side by side transversely instead of axially with respect to the truck and the corresponding levers are connected to corresponding transverse shafts, from which the actuation is transferred to the distributor by means of respective transmission rods which are arranged parallel to the longitudinal axis of the truck.

This layout provides a strict mirror-symmetry of the levers of the control sets with respect to the central longitudinal plane of the truck, but it requires considerable transverse space, which is not always available, and the maneuver of the innermost levers can furthermore be hindered by the outermost ones and this can cause unintended actuations, or the simultaneous actuation of two or more levers.

Disclosure of the Invention

The aim of the present invention is to obviate these drawbacks of conventional layouts and this aim is achieved with a duplicate layout of axial sets of control levers which has the specific characteristics stated in the appended claims.

Substantially, the layout according to the invention is a duplicate layout of sets of control levers of a distributor of hydraulic equipment for trucks, particularly for hydraulic cranes, wherein the sets have the same axial sequential arrangement of the levers as specified, a direct control set being provided with first levers whose respective arms are axially aligned with first forks for the articulation of the ends of corresponding transmission rods and the other duplicate control set being provided with second levers whose arms are axially offset with respect to second forks for the articulation of the other ends of the transmission rods, each one of the axially offset arms being connected to said corresponding second forks by means of its own arm portion, which portion is folded substantially at right angles and extends parallel to the axis of the pivoting shaft of the second articulation forks.

In this manner, with reference to a preset direction of sequential extension of the levers of said duplicate set, the first lever on the left actuates the oscillation of the last fork on the right and the last lever on the right actuates the oscillation of the first fork on the left.

Brief description of the drawings

Further characteristics and advantages of the duplicate layout according to the present invention will become apparent from the following detailed description and with reference to the accompanying drawings, wherein:

• Figure 1 is an exploded perspective view of the duplicate layout of the control sets of a distributor, arranged on either side of a truck or the like, according to the present invention;
• Figure 1a is a detail view of the pivoting system of the transmission rods of the second forks;
• Figure 2 is an enlarged-scale view of a detail of Figure 1.

Ways of carrying out the invention

In Figure 1, reference numeral 10 generally designates the hydraulic distributor that activates the different functions Fa-Fb-Fc-Fd-Fe of a hydraulic unit, typically a crane with telescoping arms (not shown), which is installed on a truck or the like.

In a manner known per se, the distributor 10 is controlled by similar axial sets 11-12, each provided with respective levers 110a-110e and 120a-120e, which are arranged on either side of the truck. The levers of each set, whose number is equal to the number of functions to be controlled, are arranged side by side along a direction which is parallel to the longitudinal axis of the truck and have a progressive sequential layout, indicated by a succession of letters of the alphabet which are, for example, ordered from left to right, for both sets 11-12, so that the operator encounters the same sequential distribution both when he works on the set 11 and when he works on the set 12.

For this purpose, according to the invention, a direct control set, for example the set 11, is provided with a bundle of levers 110a-e, each of which has a respective straight arm which is axially aligned with a first set of forks 13'a-e for the articulation of the ends of corresponding rods 14a-e for transmitting the actuation to the other duplicate control set 12. Said duplicate control set is instead provided with respective levers 120a-e in which the respective arm is axially offset with respect to the forks 13"a-e of a second set which are designed to articulate the other ends of the actuation transmission rods 14a-e.

More specifically, and as clearly shown in the Figures, each lever such as 120a-e is connected to the corresponding transmission fork 13"a-e by means of a portion 121a-e of its own arm which is folded substantially at right angles and lies parallel to the axis of the shaft 15 for the pivoting of the set of forks 13"a-e. In this manner, by way of the layout according to the invention, the intended reversal of the controls is obtained which allows the corresponding levers of the two sets, the direct one and the duplicate one 11-12, such as for example the lever 110a and the lever 120a, to act on the same valve of the distributor 10.

The disclosures in Italian Utility Model Application No. TO98U000109 from which this application claims priority are incorporated herein by reference.