Compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines

Abstract: Compact rear-mounted device (1) for adjusting the suspension of driver's seats (2), particularly for agricultural machines, having a first pair of contrast springs (4) whose action can be integrated by virtue of the intervention of at least one second pair (11) of springs which are parallel to the first ones; the intervention can be performed by virtue of related engagement elements (14) which are suitable to connect or disconnect the second additional pair of springs to or from the first one.

Description: The present invention relates to a compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines (see for example GB-A-2 120 931, corresponding to the preamble of claim 1). In the field of the production of agricultural machines, one of the most important problems concerns the comfort which the drivers must enjoy in order to spend many working hours sitting in their seats. The importance of this problem is so great that there are international statutory provisions which control the manufacture of seats; said provisions are very strict and deal with various parameters, such as for example the anatomical configuration of the seats, their suspension system and others. The known art in the field of suspensions provides for a number of different solutions which have the purpose of varying the type of reaction to the load according to the physical characteristics (weight) of each driver. In detail, seats are currently manufactured which entrust their suspension to rear-mounted structures, i.e. structures compactly located behind the driver's back, which offer the advantage of being very compact but do not allow, by themselves, to obtain the above described diversification of behavior and must be integrated, in order to obtain it, with a further parallelogram-like structure arranged below the horizontal portion of the seat, with an evident increase in bulk and production costs. The technical aim of the present invention is to solve the above described problems of the known art by providing a compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines, which despite maintaining the compact rear-mounted structure allows to comfortably and very practically vary the stiffness of the suspension. This aim is achieved by a compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines, as defined in claim 1. Further aims, characteristics and advantages of the invention will become apparent from the description of a preferred but not exclusive embodiment of a compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a lateral elevation sectional view of the device according to the present invention; figure 2 is a rear elevation view thereof; and finally figure 3 is an enlarged-scale detail view of the devices for moving the hook. With particular reference to the above figures, the reference numeral 1 generally designates a compact rear-mounted device for adjusting the suspension of driver's seats 2 for agricultural machines, which is of the type composed of a main frame 3 which defines the rear-mounted unit and which can slide vertically in conventional related guides which are not illustrated in the drawings. The sliding of the frame 3 occurs in contrast with a first pair of helical traction springs 4 whose upper ends are engaged with a first upper cross-member 5 which can be positioned at levels which can be set by virtue of related adjustment means 6. Said adjustment means consist of at least one threaded pivot 7 which is provided, at its upper end, with an actuation knob 8 and which is rotatably accommodated in the upper portion 3a of the main frame 3; a complementarily threaded nut/sleeve 9 engages the lower end of the pivot 7 and is rigidly supported by said first cross-member 5. The lower ends of the pair of springs 4 are in turn engaged with a second lower cross-member 10 which is parallel to said first cross-member 5 and which is rigidly associated with the seat 2. The upper ends of a second additional pair of helical springs 11, whose stiffness is preferably different from that of the first pair 4, are also engaged with said first cross-member 5, while the opposite lower ends are in turn engaged with a third cross-member 12 which is parallel to the second one and which can be engaged therewith by virtue of related engagement elements 13. Said engagement elements consist of at least one hook 14 whose base 14a is articulated to the second cross-member 10, while its upper pawl 14b is suitable to engage a corresponding slot 15 defined in the third cross-member 12. The hook 14 is moved by means of actuation devices 16 which comprise an actuation rod 17 whose lower end 17a is articulated to the base 14a of the hook 14 and whose upper end 17b is articulated to the rotation fulcrum 18 of an eccentric element 19 which can be actuated so that it rotates by means of an actuation lever 20 which extends out of the device 1 and which acts with the interposition of elastic means 21 which are suitable to keep the eccentric element 19 in position. The operation of the invention is as follows: in normal use, the seat 2 is sprung by virtue of the action of the first pair of springs 4, while the second pair 11 is prevented from intervening by acting on the lever 20, by means of which the devices 16 keep the pawl 14b extracted from the slot 15, thus making the third cross-member 12 independent of the second one 10. When the weight of the driver varies as the drivers change, or if a same driver wishes to change the stiffness of the suspension, the devices 16 are actuated by acting on the lever 20 again and, by making the hook 14 rotate, allow the pawl 14b thereof to enter said slot 15, thus coupling the second cross-member 10 to the third one 12. This produces the cooperation of the action of the first pair of springs 4 and of the second pair 11, stiffening, in other words, the elastic resistance of the device 1 without however requiring the provision, below the horizontal portion of the seat, of any further bulky device suitable to provide the required additional reaction to the weight applied to the seat 2. In practice it has been observed that the invention thus described achieves the intended aim and objects and that by virtue of its intrinsic nature it allows, at the same time, to comply with the currently applicable national and international statutory provisions. All the details may furthermore be replaced with other technically equivalent elements. In practice, the materials employed, as well as the dimensions, may vary according to the scope of the invention as defined by the following claims the same holds in general for modifications and variations of which the invention herein conceived is susceptible. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: Compact rear-mounted device (1) for adjusting the suspension of driver's seats (2), particularly for agricultural machines, comprising a main frame (3) which can slide vertically in related guides in contrast with a first pair of springs (4), the first ends of said first pair of springs (4) being engaged with a first upper cross-member (5) and the second ends of said first pair of springs (4) being engaged with a second cross-member (10) which is parallel to said first cross-member, characterized in that said first upper cross-member (5) can be arranged at adjustable levels by virtue of related adjustment means (6) and in that said second cross-member (10) is rigidly associated with the seat, the ends of at least one second additional pair of springs (11) being furthermore engaged with said first cross-member (5), said second pair of springs being parallel to said first springs, the opposite ends of said second pair of springs being engaged with a third cross-member (12) which is parallel to the second one and which can be engaged therewith by virtue of related engagement elements (13), the intervention of said second additional pair of springs being a function of the weight applied to the seat. Compact rear-mounted device for adjusting the suspension of drivers's seats, particularly for agricultural machines, according to claim 1, characterized in that said first pair of springs (4) and said second additional pair of springs (11) are of the helical type and are arranged vertically and parallel to one another. Compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines, according to claim 1, characterized in that said means for setting the level of said first cross-member are constituted by a threaded pivot (7) which is provided, at its upper end, with an actuation knob (8), said pivot being accommodated vertically so that it can rotate in the upper portion (3a) of the main frame (3), a complementarily threaded nut/sleeve (9) engaging said pivot and being rigidly supported by said first cross-member (5), the rotation of said pivot being suitable to cause the lifting or lowering of said first cross-member (5). Compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines, according to claim 1, characterized in that said engagement elements (13) for the coupling between said second (10) and third (12) cross-members are constituted by at least one hook (14) whose base (14a) is articulated to the second cross-member (10) about a horizontal axis and whose upper pawl (14b) is suitable to engage a corresponding slot (15) defined in the third cross-member (12), said hook being moved by virtue of related actuation devices (16). Compact rear-mounted device for adjusting the suspension of driver's seats, particularly for agricultural machines, according to claim 4, characterized in that said actuation devices (16) for moving the hook (14) comprise an actuation rod (17) one (17a) of whose ends is articulated to the base (14a) of the hook, the opposite end (17b) being articulated to the rotation fulcrum (18) of an eccentric element (19) which can be rotatably actuated by means of an actuation lever (20) which extends out of the device, with the interposition of elastic means (21) for maintaining the position of the eccentric element.

Inventors: GOLDONI LEO, GOLDONI, LEO
Applicants: GOLDONI S P A, GOLDONI S.P.A.
Application year: 1992
Main classification: B60N2
IPC codes: B60N2