Patent Description:
<CIT> discloses a step ladder for a work vehicle according to the preamble of claim <NUM>.

Work vehicles generally comprise a main body and traction means for allowing the motion of the main body on the ground and one or more step ladders, which are adapted to allow a user to move between distinct points on the main body. For example, tractors are usually provided with a step ladder that allows the user to climb in and out of a cab defined by the main body.

As known, step ladders comprise a frame and one or more steps, which are arranged one above the other along a vertical direction. The steps are preferably at least partially staggered in succession along a transversal direction to both the aforementioned vertical direction and to a movement direction of the vehicle.

In detail, it is possible to define a height of the step ladder, i.e. the total extension of the step ladder along the vertical direction, and a length of the step ladder, i.e. the total extension of the step ladder along the transversal direction. It is further possible to define a slope of the step ladder as the ratio of the height to the length of the step ladder.

As is known, for a given height, a lower slope of the step ladder corresponds to a greater comfort for the user and to a greater length of the step ladder.

However, the length of the step ladder is limited by homologation requirements of the vehicle, which set a maximum transversal encumbrance of work vehicles.

Therefore, the need is felt to obtain an optimized step ladder that can be comfortably used, while at the same time complying with the homologation requirements.

An aim of the present invention is to satisfy the above mentioned needs in a cost effective and optimized manner.

The aforementioned aim is reached by a step ladder, as claimed in the appended independent claims.

Preferred embodiments of the invention are realized according to the claims dependent or related to the above independent claims.

With reference to <FIG>, numeral <NUM> indicates a work vehicle, in particular an agricultural vehicle, such as a tractor or an earth moving machine.

Work vehicle <NUM> comprises a main body <NUM>, which preferably defines a cab <NUM> for the user, an undercarriage <NUM> and traction means <NUM>, for allowing the motion of main body <NUM> and undercarriage <NUM> on the ground, such as wheels or tracks.

The work vehicle <NUM> further comprises a step ladder <NUM>, which is configured to be fixed to a portion of work vehicle <NUM>. In the embodiment shown, as shown in <FIG>, step ladder <NUM> is arranged in proximity of cab <NUM> and fixed to the main body <NUM> of work vehicle <NUM>.

Step ladder <NUM> essentially comprises a frame <NUM> configured to be fixed to the aforementioned portion of work vehicle <NUM> and a plurality of steps <NUM>, <NUM> carried by frame <NUM>.

Steps <NUM>, <NUM> are arranged one above the other along a direction Z and extend along a direction Y, which is transversal to direction Z. In the embodiment shown, direction Z is, in use, vertical with respect to the ground and direction Y is perpendicular to direction Z.

In detail, steps <NUM>, <NUM> are at least partially staggered along a direction X, which is transversal to directions Z and Y, as shown in <FIG>.

In the described embodiment, step ladder <NUM> is fixed to work vehicle <NUM> in such a manner that direction Y is substantially parallel to a movement direction of vehicle <NUM> and exemplarily comprises two steps, namely an upper step <NUM> and a lower step <NUM>.

Upper and lower steps <NUM>, <NUM> each comprise a tread <NUM>, which is substantially planar and is adapted to be stepped on by a user of the work vehicle <NUM>. In the embodiment shown, upper and lower steps <NUM>, <NUM> are carried by frame <NUM> in such a manner that respective treads <NUM> extend perpendicularly to direction Z.

The distance along direction Z between respective treads <NUM> of upper and lower steps <NUM>, <NUM> defines a rise r between upper and lower steps <NUM>, <NUM>, as shown in <FIG>.

It is also possible to define a height h of step ladder <NUM>, i.e. the total extension of step ladder <NUM> along direction Z, a length L of step ladder <NUM>, i.e. the total extension of step ladder <NUM> along direction X, and a mean slope α of step ladder <NUM> as the ratio of height h to length L.

Furthermore, frame <NUM> comprises a pair lateral supports, which are spaced from each other along direction Y, and which are configured to carry the aforementioned steps <NUM>, <NUM>.

In particular, the lateral supports are wings <NUM>, <NUM>, i.e. comprise a single substantially flat wall, which are spaced from each other along direction Y, namely a left wing <NUM> and a right wing <NUM>. In the embodiment shown, left and right wings <NUM>, <NUM> are parallel to each other.

Preferably, frame <NUM> further comprises a main portion <NUM>, which carries left and right wings <NUM>, <NUM> and is arranged transversally to these latter. According to the embodiment shown, left and right wings <NUM>, <NUM> are arranged at respective opposite ends of main portion <NUM> along direction Y and are rounded to it. Preferably, left and right wings <NUM>, <NUM> and main portion <NUM> are formed as a single piece, e.g. in a metallic material. Main portion <NUM> or wings <NUM>, <NUM> can be advantageously fixed to the main body <NUM> of the work vehicle <NUM> to fix the step ladder <NUM> to the latter.

Advantageously, one or more steps <NUM>, <NUM> are movably carried by frame <NUM>, so that they can be slidably adjusted along direction X between a first operative position I and a second operative position II, in order to vary mean slope α between such first and second operative positions I, II.

According to the invention, step ladder <NUM> further comprises cam means <NUM>, which support in a movable manner a side 4a of one or more steps <NUM>, <NUM> with respect to frame <NUM>, and fixing means <NUM>, which lock a side 4b of said one or more steps <NUM>, <NUM> with respect to frame <NUM> in first or in second operative positions I, II.

In detail, sides 4a and 4b are opposite sides of said one or more step <NUM>, <NUM> along direction Y, namely right and left sides. In further detail, upper and lower steps <NUM>, <NUM> are arranged between left and right wings <NUM>, <NUM> along direction Y so that left side 4a cooperates with left wing <NUM> and right side 4b cooperates with right wing <NUM>.

In the following, according to the exemplarily embodiment and for sake of clarity, upper step <NUM> is stationary with respect to frame <NUM> and lower step <NUM> is movably carried by frame <NUM>.

In particular, first operative position I corresponds to a retracted position of lower step <NUM> with respect to frame <NUM> (see <FIG>, <FIG>) and second operative position II corresponds to an advanced position of lower step <NUM> with respect to frame <NUM> (see <FIG>, <FIG>).

According to the above, lower step <NUM> can assume:.

In detail, value L1 is lower than value L2, which is equal to the maximum extension of the step ladder <NUM> along direction X (see <FIG>).

Preferably, lower step <NUM> is further slidably adjustable in a third operative position III, which is interposed between first and second operative positions I, II along direction X (see <FIG>, <FIG>), thereby defining a length L3 of step ladder <NUM> in direction X.

In detail, value L3 is lower than value L2 but greater than value L1 (see <FIG>). Preferably, third operative position III is arranged in the middle between first and second operative positions I, II along direction X.

Therefore, it is possible to define three values α1, α2 and α3 of mean slope α when lower step <NUM> is respectively in first, second and third operative positions I, II, III. In detail, value α1 is greater than value α2 and value α2 is greater than value α3.

Furthermore, cam means <NUM> comprise, in turn, a guide <NUM> and a slider <NUM>, which is adapted to slide, in use, in guide <NUM>.

In detail, guide <NUM> is formed in one between frame <NUM> and lower step <NUM> and is directed along direction X. In the embodiment shown, guide <NUM> is conformed as an opening passing through left wing <NUM> (see <FIG>).

Consequently, slider <NUM> is carried by the other one between frame <NUM> and lower step <NUM>. In detail, slider <NUM> is integrally connected to lower step <NUM>, in particular at left side 4a. In further detail, slider <NUM> is welded to lower step <NUM>.

In the embodiment shown, slider <NUM> is substantially a pin comprising an attaching portion 9a, which is fixed to left side 4a and an engaging portion 9b, which is adapted to engage guide <NUM> and protrudes from attaching portion 9a along direction Y. In detail, attaching portion 9a and engaging portion 9b are formed as a single piece.

Step ladder <NUM> further comprises cam means <NUM> supporting in a movable manner right side 4b of lower step <NUM> (<FIG>).

Cam means <NUM> comprise, in turn, a guide <NUM> and a slider <NUM>, which is adapted to slide in guide <NUM> (<FIG>).

Guide <NUM> is formed in one between frame <NUM> and lower step <NUM> and slider <NUM> is carried by the other one between frame <NUM> and lower step <NUM>.

In detail, guide <NUM> is defined by an opening <NUM> extending along direction X and passing through right wing <NUM>. Slider <NUM> is conformed as a pin and is integrally connected to lower step <NUM>. In further detail, slider <NUM> is welded to right side 4b.

In the exemplarily embodiment, slider <NUM> is a substantially cylindrical pin while slider <NUM> is a substantially flat pin.

In particular, opening <NUM> has a substantially rectangular shape, preferably rounded at its corners, therefore defined by a pair of end walls 13a, 13b, which are opposite to each other along direction X, an upper wall 13c and a lower wall 13d, which are opposite to each other along direction Z.

Opening <NUM>, passing through the right wing <NUM>, allows the insertion of slider <NUM>. End walls 13a, 13b, namely a front wall 13a and a rear wall 13b, define therefore respective abutments for slider <NUM> along direction X.

In detail, the distance along direction Z between lower wall 13d and upper wall 13c varies along direction X. In particular, lower wall 13d has a height-variable profile parallel to direction Z.

Advantageously, lower wall 13d comprises a plurality of protrusions, which determine the height-variable profile of lower wall 13d along direction Z, in addition, the protrusions extend along direction Z and are directed from lower wall 13d towards upper wall 13c. In detail, such protrusions are arranged at least at three points of lower wall 13d along direction X. In the described embodiment, the three points of lower wall 13d correspond to the first, second and third operative positions I, II and III of lower step <NUM>.

In detail, slider <NUM> is adapted to slide between front wall 13a, which corresponds to first operative position I of lower step <NUM> and rear wall 13b, which corresponds to second operative position II of lower step <NUM>.

In further detail, when lower step <NUM> is in one of first, second and third positions I, II, III, slider <NUM> simultaneously contacts lower wall 13d at one of the protrusions and upper wall 13c (see <FIG>).

Furthermore, fixing means <NUM> comprise a coupling element <NUM> and a pair of seats <NUM>, <NUM>, namely a first seat <NUM> and a second seat <NUM>, which are realized in one between lower step <NUM> and frame <NUM>. Preferably, first and second seats <NUM> and <NUM> are aligned along direction X and coupling element <NUM> is configured to selectively engage one of first and second seats <NUM>, <NUM>, to lock the position of lower step <NUM> with respect to frame <NUM> in first and second operative positions I, II, respectively.

With reference to the first embodiment depicted in <FIG>, coupling element <NUM> is threaded element. In detail, first and second seats <NUM>, <NUM> are threaded holes, which are adapted to be engaged by the thread of coupling element <NUM>.

Alternatively, as shown in a second embodiment depicted in <FIG>, coupling element <NUM> is a pin that can be fixed to right wing <NUM> via a lynchpin connection <NUM>. In the described embodiment, such lynching connection <NUM> comprises a dowel <NUM> configured to be inserted in a through hole realized in the coupling element <NUM> and that can be maintained in such coupled position by elastic means <NUM>. For sake of brevity, such embodiments will not further be described in detail.

According to a not-shown alternative embodiment, coupling element <NUM> is carried by one between lower step <NUM> and frame <NUM> and first and second seats <NUM>, <NUM> are formed in the other one between lower step <NUM> and frame <NUM>.

Fixing means <NUM> further comprise a third seat <NUM>, which is interposed between first and second seats <NUM>, <NUM> along direction X. In particular, coupling element <NUM> is configured to selectively engage third seat <NUM> to lock, in use, lower step <NUM> in third operative position III (<FIG>, <FIG>, <FIG>).

In the described embodiment, third seat <NUM> is arranged in the middle between first and second seats <NUM>, <NUM> along direction X. In addition, third seat <NUM> is arranged at a higher position with respect to first and second seats <NUM>, <NUM> along direction Z.

Step ladder <NUM> further comprises a movable connection assembly <NUM> to movably couple right side 4b with frame <NUM>. Preferably, such movable connection assembly <NUM> comprises a connecting rod <NUM>.

Connecting rod <NUM> comprises a first end 15a, which is hinged to frame <NUM> by means of a first hinge <NUM> and a second end 15b, which is hinged to slider <NUM> by means of a second hinge <NUM>. First and second ends 15a, 15b are opposite to each other (<FIG>).

In particular, fixing means <NUM> are adapted to lock the position of movable connection assembly <NUM> with respect to frame <NUM>.

According to the above, fixing means <NUM> are adapted to lock connecting rod <NUM> at an intermediate portion between first and second ends 15a, 15b. In detail, connecting rod <NUM> comprises a hole <NUM>, which is formed at an intermediate portion between first and second ends 15a, 15b (see <FIG>). In further detail, coupling element <NUM> is adapted to simultaneously engage hole <NUM> and one of first, second or third seats <NUM>, <NUM> or <NUM>, to lock lower step <NUM> in one of first, second or third operative positions I, II, III, respectively.

In addition, connecting rod <NUM> is also slidable with respect to first hinge <NUM> (<FIG>). In detail, connecting rod <NUM> comprises a slot <NUM>, which is adapted to be slidably engaged by first hinge <NUM>.

As shown in <FIG>, the position of hole <NUM> along direction Z is variable, as a consequence of the rotation of connecting rod <NUM> with respect to first hinge <NUM>. In detail, the position of hole <NUM> along direction Z when step ladder <NUM> is in third operative positions III is different, in particular higher, from the position of hole <NUM> when step ladder <NUM> is in first or in second operative positions I, II.

In particular, as described above, third seat <NUM> is arranged at a higher position with respect to first and second seats <NUM>, <NUM> along direction Z in such a manner that, when step ladder <NUM> is in third operative position III, third seat <NUM> is aligned with hole <NUM> and both third seat <NUM> and hole <NUM> are simultaneously engageable by coupling element <NUM>.

The operation of the step ladder <NUM> according to the invention and described as above is the following. In particular, the operation will be described starting from a condition in which lower step <NUM> is locked in first operative position I. In this condition, length L is equal to value L1 and mean slope α is equal to value α1 (<FIG>).

In order to set lower step <NUM> in second or in third operative positions II, III, coupling element <NUM> is disengaged from first seat <NUM> and lower step <NUM> is subsequently slid parallel to direction X. Preferably, coupling element <NUM> is disengaged from first seat <NUM>, while remaining at least partially engaged with hole <NUM>.

While lower step <NUM> is moved, slider <NUM> slides in guide <NUM> and slider <NUM> slides in guide <NUM>. In detail, slider <NUM> moves from rear wall 13b towards front wall 13a.

In addition, connecting rod <NUM> rotates with respect to first and second hinges <NUM>, <NUM> and slides with respect to first hinge <NUM>. In detail, slot <NUM> slides with respect to first hinge <NUM>.

Once lower step <NUM> reaches second or third operative positions II, III, lower step <NUM> is subsequently locked with respect to frame <NUM> by fixing means <NUM>. In detail, coupling element <NUM> engages second or third seats <NUM>, <NUM>, while being engaged with hole <NUM>. As a consequence, connecting rod <NUM> is also locked with respect to frame <NUM>.

In detail, when lower step <NUM> is set in second operative position II, length L is equal to value L2 and mean slope α is equal to value α2. When lower step <NUM> is set in third operative position III, length L is equal to value L3 and mean slope α is equal to value α3.

The above operation is a manual operation of the step ladder <NUM>. Clearly, it can be foreseen to provide step ladder <NUM> with automatic actuation means for automatically slidably moving lower step <NUM> with respect to frame <NUM> and automatically engaging or disengaging fixing means <NUM>.

In view of the foregoing, the advantages of step ladder <NUM> according to the invention are apparent.

In particular, since lower step <NUM> is movably carried by frame <NUM> so that it can be slidably adjustable along direction X between first and second operative positions I, II, length L and mean slope α of step ladder <NUM> can be easily varied depending on the user's needs.

Accordingly, step ladder <NUM> can be comfortably used, while complying with the homologation requirements of work vehicle <NUM>.

In fact, when lower step <NUM> is in first operative position I, the encumbrance of work vehicle <NUM> parallel to direction X is minimized so as to meet the homologation requirements and mean slope α is equal to its maximum value, i.e. α1.

On the contrary, when lower step <NUM> is in second operative position II, the encumbrance of work vehicle <NUM> parallel to direction X is maximized and mean slope α is equal to its minimum value, i.e. α2, and the user's comfort is maximized.

Furthermore, since cam means <NUM> support in a movable manner left side 4a with respect to frame <NUM> and fixing means <NUM> lock right side 4b with respect to frame <NUM>, it is possible to adjust the position of lower step <NUM> without completely removing it from frame <NUM>.

In case of automatic sliding of lower step <NUM> and engaging/disengaging of the fixing means <NUM>, the passage between the different operative positions I, II, III of lower step <NUM> can be realized in a totally automatic way without any intervention of the user.

It is clear that modifications can be made to the described step ladder <NUM> which do not extend beyond the scope of protection defined by the claims.

Claim 1:
Step ladder (<NUM>) for a work vehicle (<NUM>), comprising a frame (<NUM>) configured to be fixed to a portion of said work vehicle (<NUM>) and a plurality of steps (<NUM>; <NUM>) carried by said frame (<NUM>);
said plurality of steps (<NUM>; <NUM>) being arranged one above the other along a first direction (Z) and extending along a second direction (Y) transversal to said first direction (Z);
wherein at least one (<NUM>) among said steps (<NUM>; <NUM>) is movably carried by said frame (<NUM>) so that it can be slidably adjustable along a third direction (X) between at least a first and a second operative positions (I, II); said third direction (X) being transversal to said first and second directions (Z, Y);
said step ladder (<NUM>) further comprising first cam means (<NUM>) and fixing means (<NUM>), said first cam means (<NUM>) supporting in a movable manner a first side (4a; 4b) of said at least one step (<NUM>) with respect to said frame (<NUM>) and said fixing means (<NUM>) locking a second side (4b; 4a) of said at least one step (<NUM>) with respect to said frame (<NUM>) in said at least first and second operative positions (I, II),
said step ladder is characterized in that said fixing means (<NUM>) comprise a coupling element (<NUM>) and at least two seats (<NUM>, <NUM>) realized in one between said at least one step (<NUM>) and said frame (<NUM>) along said third direction (X), said coupling element (<NUM>) being configured to selectively engage one of said seats (<NUM>, <NUM>) to lock, in use, the position of said at least one step (<NUM>) with respect to said frame (<NUM>).