Vehicle with Trailer Operatively Connected Thereto With a Cardan

Abstract

Disclosed herein is vehicle (1) with trailer (2) operatively connected thereto with a cardan (3), said cardan (3) comprising a power take-off, said power take-off being switched off when said cardan (3) forms with said vehicle (1) and/or with said trailer (2) an angle (α; β) smaller than a first threshold value and/or larger than a second threshold value and being switched on when said angle exceeds again said first threshold value or goes below said other threshold value, due to suitable actuators. According to the invention, it provides angle (δ) detection means between the steering wheels (5) and the axle (A) of the vehicle and means apt to correlate said angle (δ) between the steering wheels (5) and the axle (A) of the vehicle (1) with the angle (α; β) comprised between the cardan (3) and said vehicle (1) and/or said trailer (2).

Claims

1) Vehicle (1) with trailer (2) operatively connected thereto with a cardan (3), said cardan (3) comprising a power take-off, said power take-off being switched off when said cardan (3) forms with said vehicle (1) and/or with said trailer (2) an angle (α; β) smaller than a first threshold value and/or larger than a second threshold value and being switched on when said angle exceeds again said first threshold value or goes below said second threshold value, due to suitable actuators, comprising angle (δ) detection means between the steering wheels (5) and the vehicle axle (A) and means apt to correlate said angle (δ) between the steering wheels (5) and the axle (A) of the vehicle (1) with the angle (α; β; ε) comprised between the cardan (3) and said vehicle (1) and/or the trailer (2), to characterised in that the angle (ε) which must be compared to the threshold value is calculated according to the relationship:
ε=180°−δ−arcsen(m/*senδ)  (1) wherein: m=length of an arm of the cardan l=length of another arm of the cardan δ=angle between the steering wheels and the vehicle axle.

2) Vehicle as in claim 1), characterised in that it consists of a tractor.

3) Vehicle as in claim 1), characterised in that said trailer is a towed load.

4) Vehicle as in claim 1), characterised in that said cardan (3) is a telescopic cardan (3).

5) Vehicle (1) as in claim 1), characterised in that said first threshold value is 35° and said second threshold value is 145°.

6) Vehicle as in claim 1), characterised in that it furthermore comprises an electronic level.

Description

[0020] Further features and advantages of the invention will anyhow be more apparent from the following detailed description of a preferred embodiment, given by mere way of non-limiting example and illustrated in the accompanying drawings, wherein:

[0021] FIG. 1 is a schematic side view of a vehicle with trailer according to the present invention;

[0022] FIG. 2 is a schematic plan view of a vehicle with trailer according to the present invention, showing the vehicle and the trailer in rectilinear movement;

[0023] FIG. 3 is a view similar to FIG. 2, but during a curve of the vehicle;

[0024] FIG. 4 is a schematic plan view of the bottom of a vehicle, according to the present invention, during the straight run;

[0025] FIG. 5 is a view similar to FIG. 4, but during a curve of the vehicle;

[0026] FIG. 6 is a schematic view of an embodiment of the present invention, with the cardan being highlighted; and

[0027] FIG. 7 is a view similar to FIG. 6, but with the use of a telescopic cardan.

[0028] The description that follows is directed to the exemplary case of a tractor with a trailer. The trailer, in turn, may contain operating units, such as a spraying pump, a lawn mower, or the like. Preferably, said trailer is a towed load. Obviously, despite the above, the present invention is not limited to the case of the tractor with towed trailer, but it comprises any vehicle with a trailer joined together with a cardan. It is understood that, if the trailer is towed, the towing action of the trailer is not performed by the cardan—which only realises a functional connection for the energy transmission to the machines on the trailer —, but by hooking one eye of the drawbar of the trailer to a pin of the tractor.

[0029] FIG. 1 shows a tractor 1, coupled to a trailer 2 through a cardan 3. The tractor 1 includes rear steering wheels 4 and front steering wheels 5.

[0030] The cardan 3 can be of the normal type, as shown in FIG. 6, or of the telescopic type, as shown in FIG. 7.

[0031] The normal cardan comprises two arms 6, 7, which are joined in the joint 8.

[0032] The telescopic cardan comprises two arms 9, 10, carried by the vehicle 1 and the trailer 2, respectively, each joined by a respective cardan joint to an elastic joint 11, able to lengthen and shorten telescopically, depending on the direction and intensity of stresses.

[0033] FIG. 2 schematically shows the linear driving of the vehicle 1 and the trailer 2. The angles α, between the vehicle 1 and the cardan 3, and the angle β between the trailer 2 and the cardan 3, are both approximately 90°. FIG. 3 shows the situation in which the vehicle 1 and/or the trailer 2 begin to curve and the angles α and β vary due to the curve. FIGS. 4 and 5 illustrate the same situation, in a (bottom) plan view on the vehicle floor pan 1. In FIG. 4 the wheels 4, 5 are straight and the angles γ and δ, which form, respectively, with the axes A, are 180°. FIG. 5 shows that, while the angles γ comprised by the non-steering wheels 4 with the axle A are the same, i.e. 180°, the angles δ comprised by the steered wheels 5 with the same axle A are very different.

[0034] The inventors of the present invention have performed extensive studies, according to which they have come to the surprising conclusion that the angles δ are in a direct biunivocal relationship with the angles α and β, respectively. On the basis of this finding, the present invention has been accomplished.

[0035] As mentioned previously, angle δ detection means are mounted on the vehicle 1, between one or both of the steered wheels and the axle A of the vehicle. The detected data is sent to a computer, which uses it to derive the angle α between the vehicle 1 and the cardan 3, and the angle β between the trailer 2 and the cardan 3. When the value of one or both of the angles α and β goes below a first threshold value (for example 35°) or above a second threshold value (for example 145°), the computer sends a signal to the actuator of the power take-off, which determines its switching off. When one or both of the angles α and β go above a threshold value (for example 35°) or below another threshold value (for example 145°), another signal is sent to the actuator of the power take-off, and the latter is switched on again.

[0036] A preferred embodiment is illustrated with reference to FIG. 6. FIG. 6 shows a cardan 3, formed by two arms 6 from the vehicle 1 and 7 from the trailer 2, joined in the joint 8. The arms 6, 7 form an angle ε therebetween. To obtain, from the angle ε, which is the angle that must remain between the two threshold values, for example 35° and 145°, at each instant, the processing system on the vehicle 1 according to the present invention starts from some data. Firstly, the length of the arms 6, 7, known at the time of construction or that is adjustable, in the case of using different trailers from time to time. Secondly, the angle δ value is used, which is detected by the detection means on the vehicle 1, according to the present invention.

[0037] If is the length of the arm 6 and m is the length of the arm 7, the relationship used by the computer to obtain the value of ε is:

ε=δ−arcsen(m/*senδ)  (1)

In fact, the vehicle 1 and the trailer 2 form an angle therebetween, the sides of which can be joined together to form a triangle, to which the trigonometry rules can be applied. The angles of the triangle are 180°−δ, ε and ζ. The height of such a triangle is Isenζ, which is equal to msenδ. It follows that ζ=arcsen (m/l*senδ). Since the sum of inner angles of a triangle is 180°, it follows that ε=180°−δ−ζ. Substituting the previous definition of ζ we obtain the relationship (1), which allows to obtain the value of ε as δ varies.

[0038] In the case illustrated in FIG. 7, with a telescopic cardan 3, the same relationship will be true for each of the angles α and β; however, it will be necessary to take in account also the changeable length of the arms 9 and 10, for which it will be appropriate to operate with a prudential value, to consider the most unfavorable conditions, or have a sensor for the length of each of arms 9 and 10, which is inserted in the calculation in the relationship similar to the relationship (1).

[0039] The cases illustrated above can also be reported in the case of angles on the cardan 3 not created by the steering action, but rather by a climb or a descent. In this case, the angle formed by the wheels with the long axle of the vehicle 1 will not detected; on the contrary, the angle formed by the vehicle 1 with the just previous road section will be detected. This data can be detected continuously by an electronic level. Therefore, a preferred embodiment of the present invention provides, in addition to the angle detection device of the wheels 5 with respect to axle A, also an electronic level for the continuous detection of the angle between the travelled road section and the just previous one. Preferably, the delay according to which the position of the previous road section is calculated, is equal to the time since the passage of the vehicle 1 until the passage of the trailer 2.

[0040] According to the above, the present invention allows to realize a vehicle 1 with trailer 2 connected thereto with a cardan 3, which preserves the cardan 3 by switching off the power take-off, when a certain angle in one direction is exceeded, and by switching it on again, when this angle threshold is exceeded in the opposite direction, so as to maximise the exploitation of the power and to avoid distractions of the operator for this operation. This increases safety and performance compared to the prior art tractors.

[0041] This is true, in particular, in the case in which the trailer 2 is a towed load and where the operator can safely forget the power take-off at all.

[0042] The present invention has hereto been described in relation to a tractor which tows another agricultural machine, but it is clear that the disclosed and claimed object matter is equally applicable to any vehicle that transport, thanks to a cardan, a trailer.

[0043] The present invention also allows to prevent the crankcase of the cardan 3 from being damaged with damages linked to operating the cardan 3 a little above the permitted angles, but for short periods of time, which do not damage the cardan 3, but which can release the crankcase, necessitating its replacement to meet the requirements of the occupational safety laws.

[0044] It is understood, however, that the invention is not to be considered as limited by the particular arrangement illustrated above, which represents only an exemplary embodiment of the same, but different variants are possible, all within the reach of a person skilled in the art, without departing from the scope of the invention itself, as defined by the following claims.

LIST OF REFERENCE NUMERALS

[0045] 1 Vehicle [0046] 2 Trailer [0047] 3 Cardan [0048] 4 Non-steering wheels (of 1) [0049] 5 Steering wheels (1) [0050] 6 Arm (of 3) [0051] 7 Arm (of 3) [0052] 8 Joint (of 3) [0053] 9 Arm (of 3) [0054] 10 Arm (of 3) [0055] 11 Elastic joint [0056] α Angle [0057] β Angle [0058] γ Angle [0059] δ Angle [0060] ε Angle