Control device for the spatial position of the suspended axle of an industrial vehicle

Abstract: A control device of the spatial position in a suspended axle for industrial vehicles essentially comprising two angular sensors (32) fitted on opposite pins (26), each of which is provided with a relative spherical coupling (27) for a panhard bar (16) interposed between an axle (11) and the chassis (15) of the industrial vehicle, each of the sensors (32) interposed between the axle (11) and the chassis (15) of the industrial vehicle being operated by elastic laminas (35, 36) and each sensor receiving motion from the corresponding rotating hub (34), the angular sensors (32) detecting the spatial oscillations of the panhard bar (16) in relation to the axle (11) and the chassis (15) of the industrial vehicle. There are two elastic laminas (35, 36) for each angular sensor (32) and these are fitted parallel to each lateral surface of the panhard bar (16), partially overlapping one another and fixed on one side to one of the angular sensors (32) and on the other to the surface of the panhard bar (16).

Description: The present invention relates to a control device of the spatial position in a suspended axle for industrial vehicles, in particular of the type with articulated connection. It must be taken into account that an axle of the aforesaid type is designed to be mounted on industrial vehicles, such as lift trucks, front loaders, backhoe loaders, graders, tractors or similar. This type of axle with articulated connection essentially comprises a central casing from which two arms extend, each carrying, at one of its ends, a wheel support. The axle is connected to the chassis of the industrial vehicle by transversal bars and longitudinal bars in relation to the vehicle, where the transversal bars are composed of a panhard bar, and moreover, damped elements are interposed between the axle and the chassis. A suspension system is known from EP-A-0 603 394, comprising buffer springs interposed between an axle and a chassis frame, a pair of double-acting cylinders provided a preset distance apart in the lateral direction of the vehicle and each pivotally supported on the tube side and rod side by the chassis frame and the axle, respectively, and a link coupled to the chassis frame at one end and to the axle at the other end thereof in such a manner that horizontal displacements in left and right, and forward and rearward directions relative to the vehicle are restricted wherein the double-acting cylinders are kept free while running, and are locked while digging work is performed. When the industrial vehicle is moved and in use, there is a problem in knowing the spatial position of at least one of the axles in relation to the chassis for correct movement of the vehicle. For this purpose, appropriate sensors should be fitted to check, moment by moment, the spatial position of the axle involved: however, it is difficult to position these as a plurality of variables are involved. In fact, the sensors are affected by elements external to the vehicle that may even break and deactivate them and, moreover, they must be suitable for the various types of chassis of the vehicle. Moreover, the accelerations to which the components of the vehicle are subjected could in turn overload the sensors if they were not appropriately supported and protected. All this causes possible imprecision in measurements, if not the actual breakage of the sensor, thus causing loss of the control measurement on the vehicle system and causing loss of reliability of the measurement. In DE 199 23 326, a retaining plate is fitted on the support frame of the vehicle, and upon the plate is suspended a pendulum switch by means of a cross joint. A curved yoke is attached to the pendulum switch. If the support frame rises or lowers at right angles to the direction of travel the pendulum switch by its two current sensors, try to maintain a vertically hanging position and come into contact with the current-conducting yoke. One of the sensors then sends a control signal to the hydraulic cylinder to readjust the frame into a horizontal position. The object of the present invention is to eliminate the technical problems expounded, by providing a control device of the spatial position in a suspended axle for industrial vehicles, in particular of the type with articulated connection, which is implemented using a limited number of reaction elements in relation to the chassis and with a position of the sensors that guarantees safe positioning of the sensors in relation to the chassis of the vehicle. Another object of the present invention is to provide a device connected to an axle that can be installed under the chassis of the vehicle in an essentially simple manner and in a protected area that is not exposed to possible knocks against external obstacles. Yet another object of the present invention is to provide a control device for a suspended axle for industrial vehicles of the type with articulated connection that is essentially simple, safe and reliable, both in its construction and in its operating position. These and other objects, according to the present invention, are obtained by providing a control device of the spatial position in a suspended axle for industrial vehicles, in particular of the type with articulated connection, according to claim 1. Other characteristics of the present invention are further defined in the subsequent claims. Advantageously, the device according to the present invention permits an increase in the safety and control of the vehicle obtaining an expansion in the operating possibilities of the industrial vehicle. In fact, the device according to the invention allows the vehicle to move faster and with greater safety, in routes of any condition. This permits the stability limits to be identified and, working if necessary in conditions in close proximity to the measured limits (although remaining within an appropriate safety range of the vehicle), to obtain maximum performance and reduce the idle times of the vehicle to thus obtain a considerable economic return. Moreover, vehicles fitted with the device according to the present invention, to control the position of the suspended axle, are safer and easier to drive in relation to those with axles on which the device is not fitted. Thus, driving is more comfort and there is an overall reduction in stress and fatigue for the operator of the industrial vehicle. Further characteristics and advantages of a control device of the spatial position in a suspended axle for industrial vehicles, in particular of the type with articulated connection, according to the present invention, will emerge more evidently from the ensuing description, given to provide a non-limiting example, with reference to the annexed schematic drawings, in which: figure 1 shows a schematic perspective view of a suspended axle for industrial vehicles of the type with articulated connection fitted with a control device of the spatial position according to the present invention, figure 2 shows an enlarged front view of the application of the device in an axle such as the one in figure 1, in which the upper sensor is not shown, figure 3 shows an enlarged section implemented along the longitudinal axis of the panhard reaction bar shown in figure 2, figure 4 shows an enlarged section of a detail of connection of the angular sensor to the corresponding support and shows the related connections. Figure 1 schematically illustrates the structure of a suspended axle for industrial vehicles, of the type with articulated connection, fitted with a control device of the spatial position according to the present invention. In brief, it can be seen in this figure that one axle 11, for example, of the two or more provided on the vehicle, comprises a central casing 12 from which two arms 13 extend. It can also be noted that one end of each of the two arms 13 is fitted with a support 14 of a wheel, not shown. The axle 11 according to the invention is also connected to a chassis 15 of the industrial vehicle both by transversal bars and longitudinal bars in relation to the vehicle. The transversal bar is provided by means of a panhard bar 16 hinged at one end to a bracket 17, integral with the casing 12 of the axle 11, and at the other end to another bracket 18 integral with the chassis 15 of the industrial vehicle. The brackets 17 and 18 are in fact supporting elements of the articulation pins of the panhard bar 16. Coupling between the panhard bar 16 and the brackets or supports 17 and 18 is provided by hinges with ball coupling. Moreover, damped elements 19 can be interposed between the axle 11 and the chassis 15 of the industrial vehicle. These damped elements 19 are preferably composed of double-acting hydraulic cylinders hinged in 23 on one side directly to brackets 20, integral with the chassis 15. Instead, rods 21 of the hydraulic cylinders are hinged in 24 to brackets 22 integral with the arms 13 of the axle 11. The hydraulic cylinders 19 are fed by a hydraulic control unit controlled electronically with the aid of the control device of the present invention. This control permits greater sensitivity to the load burdening the damped elements 19 and to the corresponding effect on the position of the vehicle and also permits excursion to be limited and enabling of a self-levelling function that may possibly be provided on the vehicle. The control device of the spatial position in a suspended axle for industrial vehicles according to the present invention is fitted on the panhard bar 16 and the brackets or supports 17 and 18 in relation to the casing 12 of the axle 11 and to the chassis 15 of the industrial vehicle. The device is essentially composed of two angular sensors fitted on the opposite pins of the panhard bar 16 to detect the angular oscillations of the panhard bar 16 in relation both to the casing 12 of the axle 11 and to the chassis 15 of the industrial vehicle on which they are installed. In particular, starting from the chassis side 15 of the industrial vehicle on a first lateral surface of the panhard bar 16 the following arrangement is envisaged. The bracket 18 fork-shaped provided with two holes 25 and 25' in its two arms, said holes 25 and 25' housing a first pin 26, also fixed to the fork-shaped bracket 18. Housed on this first pin 26 is a first ball bearing 27 which is housed, with its external part, in a first through hole 28 machined in a first end of the panhard bar 16. At one side the first pin 26 has a first enlarged head 29 which abuts externally on an arm of the fork-shaped bracket 18, while on the other side the first pin 26 carries, fixed by bolts 30 placed axially a first part of first support 31a connected to a second part of first support 31b which supports the stationary part of a first angular sensor 32. Placed inside the first support in two parts 31a and 31b, with a first bearing 33 interposed, is a first rotating hub 34, fixed to which, by means of bolts 39, are both one end of a first lamina 35 and a drive pin 40 of the rotating part of the first angular sensor 32, the first pin being fixed to the first hub 34. The first sensor 32 is instead fixed by bolts 42 to the first support 31b in turn fixed to the first support 31a by means of further bolts 41. The first lamina 35 is made of spring steel and extends parallel to the panhard bar 16 on a first lateral surface and fixed to its opposite end by bolts 37 is one end of a second lamina 36, made of the same material. Although having a spatial surface, the entire surface of the second lamina 36 is still parallel to and under the first lamina 35. The curved elastic lamina 36 turns back towards its connection point, where it is fixed by bolts 38 above the first lateral surface of the panhard bar 16. In this way the entire system to operate the angular sensors is constrained by any oscillation the panhard bar is allowed in the space, the latter being fixed by spherical anchors to the chassis. The layout of the second angular sensor on the other part of the panhard bar 16 must now be considered in relation to the support 17 fitted connected to the casing 12 of the axle 11. The layout is exactly the same and the same numbers of reference are indicated for parts with identical functions. On this second side of the panhard bar 16 the following layout is thus envisaged. The bracket 17 is also fork-shaped and is provided with two holes 25 and 25' in its two arms. Said holes 25 and 25' house a second pin 26' also fixed to the forkshaped bracket 17. Housed in this second pin 26' is the internal part of a second ball bearing 27' which is housed in a second through hole 28' machined in a second end of the panhard bar 16. On one side the second pin 26' has a second enlarged head 29' which abuts externally on an arm of the fork-shaped bracket 17, while on the other side the second pin 26' carries, fixed by bolts 30 a second support 31a' and 31b' that supports the stationary part of the second angular sensor 32' Placed inside the second support 31a' and 31b', with a second bearing 33' interposed, is a second rotating hub 34' fixed to which is both one end of a third lamina 35' and the drive pin 40 of the rotating part of the second angular sensor 32', the pin being fixed to the second hub 34'. The third lamina 35' is made of spring steel and extends parallel to the panhard bar 16 and fixed to its opposite end by bolts 37 is one end of a fourth lamina 36' made of the same material facing in the same direction turned back and under the third lamina 35'. At the other end the fourth lamina 36' is fixed by bolts 38 above the second lateral surface of the panhard bar 16, thus remaining constrained by any oscillation in the space of the panhard bar allowed by the presence of the second ball bearing 27'. A pair of such angular sensors, connected to the panhard bar 16 as described above, allow each movement in the position of the axle space in relation to the chassis to be detected, to allow any correction operation, if necessary and requested. In fact, the position of the axle in the space in relation to the chassis can be unequivocally recognized. The aforesaid hydraulic control unit controlled electronically and commanded by the position of the two angular sensors can in fact activate one or more of the damped elements 19. This is required, for example, to vary their excursion in order to perform a self-levelling function for the entire vehicle or change the position to the extent deemed necessary by the terrain and inclination of the vehicle. The function of a control device fitted to an suspended axle 11 for industrial vehicles of the type with articulated connection with panhard bar 16 is evident from the above description. It is evident that each axle 11 contributes towards supporting the industrial vehicle, in particular balancing transversal stresses by means of the panhard bar 16 and longitudinal stresses by means of the specific devices, such as a longitudinal strut or similar. Vertical stresses are balance by the damped elements 19. It can be hypothesized that owing to stresses caused, for example, by uneven ground across which the industrial vehicle is moving, the axle 11 oscillates. The different extent of these oscillations is dampened by the damped elements 19 and is detected by the angular sensors 32, 32'. This is permitted by the presence of the device according to the present invention that detects the change in the position of each axle in relation to the chassis. Movement relating to the panhard bar 16 in relation to the chassis is detected by the angular rotations of the pair of laminas 35, 35' and 36, 36' fixed to the panhard bar, which determine a rotation of the two rotating hubs fixed to the two angular sensors 32, 32' as the measurement is taken both in relation to the chassis 15 and in relation to the axle 11. It has been noticed how in a suspended axle for industrial vehicles of the type with articulated connection, a device according to the present invention can be fitted with extreme ease. This device is particularly advantageous as, in addition to being simpler and more reliable, it does not require variations in the structure of the axle, but is placed between the end joints of the panhard bar. Moreover, it is fitted in an area protected by the axle, being placed at the top, against the panhard bar. It is simple to install and being symmetrical, it is particularly simple. Moreover, it can be installed on any type of chassis irrespective of its width. The presence of the laminas makes a simple elastic coupling that easily follows the movements of the parts, although providing with the utmost precision the relative angular rotation measurements between the parts. The sensors are in no way overloaded by any excursions of the parts and hence the measurement is not misrepresented. A device thus conceived may undergo further numerous modifications and variants, all falling within the scope of the invention as defined by the appended claims; moreover, all parts may be replaced by others that are technically equivalent. Furthermore, the materials used, as well as the dimensions, may be any whatsoever according to the technical requirements.

Claims: Industrial vehicle comprising: a suspended axle (11) connected to a chassis (15) of the industrial vehicle by means including transversal bars and longitudinal bars in relation to the vehicle; said transversal bars includinga panhard bar (16); a first end of said panhard bar (16) is hinged by means of a relative ball bearing (27) on a first articulation pin (26) set in a bracket (18) integral with the vehicle chassis (15) of the suspended axle (11) about a longitudinal axis relative to the vehicle; a second end of said panhard bar (16) is hinged by means of a relative ball bearing (27') on a second articulation pin (26') set in a bracket (17) integral with a casing (12) about a longitudinal axis relative to the vehicle; and a control device of the spatial position of the suspended axle (11) in relation to said chassis (15), characterised in that said vehicle further comprises: a first and a second angular sensor (32,32') which detect the angular oscillations of the panhard bar (16) in relation to said suspended axle (11) and said chassis (15) ; said first angular sensor (32) comprising a stationary part attached to an axial end of said first articulation pin (26) by means of first supports (31a, 31b) and a first rotating hub (34) mounted axially and rotatably in the first supports (31a, 31b) said second angular sensor (32') comprising a stationary part attached to an axial end of said second articulation pin (26') by means of second supports (31a', 31b') and a second rotating hub (34') mounted axially and rotatably in the second supports (31a', 31b'); said rotating hubs (34,34') being attached to the panhard bar (16) by means of elastic laminas (35,36,35',36'); by which means said spacial position is detected. Industrial vehicle according to claim 1, characterised in that said elastic laminas (35,36,35',36') are two for each first and a second angular sensor (32,32') and are fitted parallel to each lateral surface of the panhard bar (16), partially overlapping one another and fixed on one side to one of said first and a second angular sensor (32,32') and on the other to each of said lateral surface of the panhard bar (16). Industrial vehicle according to claim 1, characterised in that each articulation pin (26,26') carries a support (31a, 31b, 31a', 31b) positioned rotating in which is a relevant bearing (33,33'), integral with which is a rotating portion (40) of each angular sensor (32,32'), the other fixed portion of said angular sensor (32,32') being fixed to said support (31a, 31b31a', 31b'). Device according to claim 3, characterised in that each of said rotating hub (34,34') is fixed by a drive pin (40) to the rotating portion of the relevant sensor (32,32').

Inventors: GAMBA TIZIANO, PANIZZOLO FABRIZIO, GAMBA, TIZIANO, PANIZZOLO, FABRIZIO
Applicants: DANA ITALIA SPA, DANA ITALIA S.P.A
Application year: 2001
Main classification: B62D55
IPC codes: B62D55