Motor vehicles – Bodies – Movable cab or operator's station
Reexamination Certificate
1999-05-06
2001-03-27
Johnson, Brian L. (Department: 3618)
Motor vehicles
Bodies
Movable cab or operator's station
C296S190070
Reexamination Certificate
active
06206121
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns improvements made to the resilient suspension of the cab or cab part, and particularly the driver's cab, of vehicles, in particular land vehicles.
BACKGROUND OF THE INVENTION
This type of suspension applies most particularly to the suspension of cabs of all-terrain vehicles such as works vehicles (public works, farm work especially to farm tractors, forestry work, mines, etc.), but also to the suspension of lorry cabs, and could have applications in other fields.
It is known, for example in respect of farm tractors or lorries, for the driver's cab to be disconnected from the frame and for suspension means to be interposed and placed at the four corners of the cab with either a passive structure (springs, shock mounts), or an active for example pneumatic structure (for example FR 2 661 387). However, this type of suspension only acts vertically and does not offset the transverse motions to which the cab is subjected.
Crossbars have also been connected to the previous components in an attempt to stabilise the cab (see for example FR 2 675 456, FR 2 653 733, FR 2 607 459): but this solution, although managing to improve the vertical suspension, has not had a satisfactory outcome in terms of damping transverse motions of the cab.
The use of torque rods can certainly allow cab stabilisation to be improved, but the result is an increase in the number of connections between the frame and the cab: vibrations of the frame are then easily transmitted to the cab and the noise level in the latter is relatively high. The document DE.A.30 00 606 shows such an arrangement with torque rods.
Lastly, stabilising devices use numerous active driving components which considerably increase the cost of the installation and do not encourage the idea of their introduction as standard to vehicles which are not top of the range vehicles.
SUMMARY OF THE INVENTION
The object of the invention is thus essentially to overcome the drawbacks and shortcomings disclosed by the prior art, and to offer an improved technical solution for the effective suspension and stabilisation of a vehicle cab relative to the frame, which uses a small number of parts connecting the frame and the cab so as to reduce the transmission of noise in the latter, which uses a very small number of active actuators so as to reduce the cost of the installation, and which to very great advantage uses combinable but distinct subassemblies to provide the various types of compensation (vertical suspension, pitching compensation, rolling compensation, front-rear shock absorption) so as to constitute a modular structure enabling user requirements to be met exactly.
All things considered, the invention aims to offer an improved solution which is more effective and less expensive than currently known solutions, and the modular structure of which admits of multiple uses.
To these ends, a vehicle comprising a frame and a cab or cab part or the like supported by said frame by resilient suspension means is characterised essentially, being arranged according to the invention, in that the resilient suspension means are essentially constituted by a main U-shaped rod interposed in an inclined or horizontal position between the frame and the cab, a main actuator being connected to said main U-shaped rod to determine its neutral position. Said main actuator may be a passive actuator (spring, possibly connected to a shock absorber for example) or else an active actuator (for example a hydraulic or air jack possibly connected to a shock absorber).
Certainly, it is already known for at least one U-shaped rod to be interposed between a frame and a cab part, for example, a driver's cab, resiliently suspended on the latter, as shown for example in the already mentioned document FR 2 607 459. However, such a U-shaped rod functions exclusively as an anti-roll rod and in no way functions as the main resilient suspension feature of the cab on the frame, the main suspension function being allocated to a set of components (springs and shock absorbers) placed at the corners of the cab according to a conventional configuration set out above and with the aforementioned associated drawbacks.
The fact of providing the main suspension with a single solitary U-shaped rod considerably restricts the connections between the frame and the suspended cab: the rod is fixed by one (or two) mounting(s) at its base and by two rotating articulations at the ends of its arms respectively. Sound bridges between cab and frame are thus reduced, and, when the cab part thus suspended is the vehicle driver's cab, the soundproofing of the latter can be very markedly improved, and at less cost, compared with current practice.
In addition, the U-shaped rod constituting the sole main suspension component, the cost of the cab suspension is markedly reduced.
Lastly, as will become clear later, it is possible to connect to this simple elementary main suspension other components appropriate for providing additional functions. It is thus possible to constitute a modular system allowing different levels of technical equipment and price which is able, from a minimum structure constituted by the U-shaped rod main suspension, to equip various ranges of vehicle: adaptation can be made on demand as a function of the technical and economic requirements to be met and the result is a marked reduction in the cost of each individual piece of equipment whatever its level of efficiency.
In a practical version which seems bound to be generally favoured, the U-shaped base formed by the main rod is fixed to the frame and the free ends of the arms of said U are fixed to the cab.
As regards the placing of the main suspension rod, it may be anticipated, also as a general rule, that the arms of the main U-shaped rod extend parallel to the vehicle longitudinal axis and are located approximately symmetrically relative to said axis; equally well then, as a function of the general configuration of the vehicle and the available space between the frame and the suspended cab, the base of the main U-shaped rod may be located approximately under the rear of the suspended cab, with the two arms pointing forwards, or else the base of the main U-shaped rod may be located approximately under the front of the suspended cab, with the two arms pointing backwards. But it would also be conceivable for the main rod to be placed transversely to the frame.
It is highly desirable to ensure that to the resilient suspension means are additionally connected cab pitching motion control means, which means may be designed in any ways suitable to meet the objective sought. However, in order to retain a simple and inexpensive structure and in order to ensure structural independence with the main suspension means so as to retain a modular aspect to the equipment, use may, preferably, be made for example of one of the following arrangements: pitching motion control means include a secondary U-shaped rod interposed between the frame and the cab, this secondary rod determining at least a third support point of the cab not aligned with the two support points determined by the main rod; or else include at least one rod or strut parallel to the arms of the main U-shaped rod connected with articulations to the cab and to the frame, said rod extending outside the plane defined by the main U-shaped rod in such a way that a deformable parallelogram layout is formed and interposed between the cab and the frame; or else again include at least two superposed cross belts, integral with the frame, determining a race for two rollers, separated longitudinally from each other and supported by the cab.
It is also possible to ensure that to the resilient suspension means are additionally connected cab rolling motion control and transverse attitude correction means, the main U-shaped rod being constituted by two half-rods the respective arms of which are angularly independent of each other and between which are interposed said rolling movement control means.
Then it is possible to use one of the foll
Etablissements Michel
Johnson Brian L.
Piper Marbury Rudnick & Wolfe
Winner Tony
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