Preloading and retracting device for wheel assembly and self-propelled cart

Abstract

The invention provides a preloading and retraction device of a wheel assembly and a self-propelled cart. The preloading and retraction device of a wheel assembly comprises a linear guide, an inner slide and an outer slide movable along the linear guide, a linear elastic member arranged to connect the two slides, a first wheel support arm integral with the inner slide, and a second wheel support arm integral with the outer slide, wherein the outer slide carries a weight-supporting wheel actuated and the inner slide carries a traction wheel in contact with the rolling surface with a preloading force related to the geometry of the system. The use of this device is particularly advantageous for supporting the wheels of a self-propelled cart of the type adapted to move along railway tracks for inspecting the underbody of railway vehicles, since it greatly facilitates the installation of the self-propelled cart on the rails and at least partially automates the installation of the self-propelled cart on the rails.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of mechanical suspensions and motion assemblies by means of wheels.

[0002] The present invention is advantageously applied to trolleys by means of wheels adapted to move within a confined space between two substantially facing guide surfaces, and more particularly to trolleys designed to move along railway tracks and to inspect the underbody of a railway vehicle. BACKGROUND

[0003] For the safety of human operators, robotic or self-driving vehicles are increasingly widespread in many sectors to replace humans from particularly difficult or dangerous activities.

[0004] In some specific applications, the above vehicles must be designed to move autonomously within a narrow and confined space between substantially vertically facing walls. For example, robotic vehicles by means of wheels or sometimes miniaturized vehicles by means of wheels for inspecting pipes or pipelines can be envisaged. In these types of vehicles, the suspension and motion assembly usually has a passive wheel with a substantially horizontal axis to support the weight of the vehicle and a motorized traction wheel with a vertical axis, or in any case inclined according to the inclination of the facing walls between which the vehicle must move forward, to center the vehicle with respect to the pipe or pipeline to be inspected.

[0005] The need and similar solutions can be found in certain vehicles for moving forward along a track, such as the subject of international application WO2020105018 A1 for a trolley by means of wheels for inspecting the underbody of a railway vehicle. This vehicle allows the inspection of the underbody of a railway vehicle directly on site without the need to transfer the vehicle to a dedicated maintenance site, since the vehicle of the invention has an overall vertical size that is extremely limited and moves forward along the tracks with the inner surfaces of the rail bars and the rail foot planes in an inclined and centered manner between the tracks so that the platform can move below the vehicle without the wheels of the vehicle itself hindering the movement of the platform.

[0006] In any case, the common problem of all the above-mentioned types of self-propelled vehicles, including those with a suspension and movement assembly having support wheels with a substantially horizontal axis and centring and movement wheels with a substantially vertical axis, is that of installation in the work environment, i.e. on the tracks, in the pipes or in the pipelines. In fact, in most cases, in order to be able to install the self-propelled vehicle in the work position, both the passive suspension wheels and the active centring and movement wheels must be able to move from a retracted configuration, with minimum overall lateral dimensions, to an extended operating configuration. For example, in the specific application of the subject of the above-mentioned international application, a platform for inspecting the undercarriages of railway vehicles, the platform must be manually lowered from above between the rails with both the passive suspension wheels and the active centring and movement wheels in the retracted configuration. When the platform is substantially in place, the support arms of the passive wheels are manually rotated into the work position and locked, after which the active wheels can be released outwardly, whereas before this they must be kept manually retracted against the action of the preloading of the springs. It can therefore be understood that the installation of the platform on the tracks, as well as the subsequent removal of the platform, must be carried out manually by non-standardised procedures and takes a considerable amount of time. SUMMARY

[0007] The object of the present application is to propose a mechanical suspension and movement assembly by means of wheels, in particular for use in a vehicle moving forward in a confined space, which solves the problems highlighted above relating to installation simplicity, installation speed and vehicle centring.

[0008] Another object of the present application is to propose a self-propelled cart for moving forward in a confined space, provided with a mechanical suspension and movement assembly by means of wheels which allows installation and removal from the confined space in which the self-propelled cart must move quickly, in a semi-automatic and standardised manner.

[0009] Still another object of the present application is to propose a self-propelled cart by means of wheels for inspecting the undercarriages of railway vehicles, which is adapted to move along a railway track below the rolling surface, taking into account all the obstacle limitations due to the variability of the railway vehicles and of the components constituting the superstructure of the railway, and which is provided with a mechanical suspension and movement assembly by means of wheels which facilitates and at least partially automates the operations of installation and removal from the track.

[0010] According to a first aspect of the present application, the above-mentioned objects are achieved by a mechanical suspension and movement assembly by means of wheels according to the present application.

[0011] According to another aspect of the present application, the above mentioned objects are achieved by a self-propelled cart according to the present application.

[0012] Further advantageous features and specific embodiments of the self-propelled cart of the present application are also described hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0013] The features of the present application will be easily understood from the following description of an embodiment thereof, provided by way of non-limiting example, with reference to the attached drawings, wherein:

[0014] - Figure 1 a perspective view of the device according to the present application is shown;

[0015] - Figure 2 a front view of the device of Figure 1 is shown;

[0016] - Figure 3 a side view of the device of Figure 1 is shown;

[0017] - Figure 4 a top view of the device of Figure 1 is shown;

[0018] - Figure 5 a schematic front view of a self-propelled cart according to the present application is shown, which is respectively inserted in: a) a confined space having a rectangular section; b) a confined space having an elliptical section;

[0019] - Figure 6 a top view of a self-propelled cart according to the present application is shown;

[0020] - Figure 7 a perspective view of the self-propelled cart of Figure 6 is shown;

[0021] - Figure 8 a perspective view of the self-propelled cart of Figure 6 mounted on a railway track is shown;

[0022] - Figure 9 a front view of the pre-loading and retraction device of the cart of Figure 6 is shown in three consecutive steps of the mounting operation for mounting the cart on a railway track. DETAILED DESCRIPTION

[0023] With reference to Figures 1 to 4 , the pre-loading and retraction device of the wheel assembly according to the present application is indicated as a whole with 10. The device 10 comprises:

[0024] - a linear guide 11,

[0025] - an inner slide 12, which is free to move along said linear guide 11,

[0026] - an outer slide 13, which is controlled to move along said linear guide 11,

[0027] - a linear elastic member 14, which is arranged to connect said inner slide 12 and outer slide 13 to each other, to prevent said inner slide 12 and said outer slide 13 from moving away and / or approaching each other in a relative manner with respect to a defined natural length distance,

[0028] - a first wheel support arm 15, which is integral with said inner slide 12, which extends substantially in the direction of said linear guide 11, and which is adapted to support at least one first wheel 16 in such a manner that it is able to rotate about a relative first axis 17, wherein the rolling direction 18 of said at least one first wheel 16 is substantially orthogonal to the direction of said linear guide 11;

[0029] - a second wheel support arm 19, which is integral with said outer slide 13, which extends substantially in the direction of said linear guide 11, and which is adapted to support at least one second wheel 20 in such a manner that it is able to rotate about a relative second axis 21, wherein the rolling direction 22 of said at least one second wheel 20 is parallel to the rolling direction 18 of said at least one first wheel 16.

[0030] A preload adjustment member 23 is interposed between at least one of said outer slide 13 and said inner slide 12 and said elastic member 14, to adjust the distance between said inner slide 12 and said outer slide 13 in the natural length condition of said elastic member 14. In the embodiment shown in the attached figures, the preload adjustment member 23 comprises a internally threaded tubular member, which is rotatably integral with the inner slide 12, and a screw, which is integral with the elastic member 14, engages in the internally threaded tubular member. The working principle of the preload adjustment member 23 is the same as the pull rod adjustment assembly well known in the art, therefore it is not shown in more detail.

[0031] The drive member is integral with at least one between said first wheel support arm 15 and said second wheel support arm 19, to rotate at least one wheel of the wheels supported by said at least one between said first wheel support arm 15 and said second wheel support arm 19. In the illustrated embodiment, the above-mentioned drive member is integral with said first wheel support arm 1 to rotate said first wheel 16, and comprises an electric motor 24, a pulley or toothed wheel 25 coaxial and integral with said first wheel 16, and a transmission belt 26 which extends between said pulley or toothed wheel 25 and the drive shaft of said electric motor 24.

[0032] An adjustable end-of-travel member 27 is provided to determine the retracted limit position of the inner slide 12 along the linear guide 11.

[0033] With reference to Figure 5 , the preloading and retraction device of the above-mentioned wheel assembly according to the present application, indicated with 10' in the attached drawings only in an extremely schematic manner, is designed to be mounted on a self-propelled cart 100' which is to be moved forward in a confined space S, in particular in which there is at least one bottom wall B on which the above-mentioned second wheel 20 can rest to support the weight of the cart 100', and at least one opposite limiting wall C on which the first wheels 16 of the two devices 10' mounted opposite the cart 100' can be pushed to centrally position the self-propelled cart 100' in the confined space and move it forward.

[0034] From this perspective, and also with reference to Figures 6 to 9 , a particular and particularly advantageous application of the preloading and retraction device of the wheel assembly according to the present application is provided in a self-propelled cart 100 adapted to move along railway tracks for inspecting the underbody of railway vehicles.

[0035] The self-propelled cart 100 comprises a platform 30 and a support and movement device by means of wheels, comprising at least two preloading and retraction devices 10 of a wheel assembly mounted in a mirror-like manner with respect to a longitudinal axis A of said platform 30, which defines the direction of advancement of the platform 30 itself.

[0036] Each of said preloading and retraction devices 10 comprises:

[0037] - a linear guide 11 anchored to said platform 30 so as to extend in the plane of said platform in a direction substantially orthogonal to the above-mentioned direction of advancement of said self-propelled cart 100,

[0038] - an inner slide 12, which is free to move along said linear guide 11,

[0039] - an outer slide 13, which is controlled to move along said linear guide 11,

[0040] - a linear elastic member 14, which is arranged to connect said inner slide 12 and outer slide 13 to each other to prevent relative movement of the inner slide 12 and outer slide 13 away and / or towards each other relative to a defined natural length distance,

[0041] - a first wheel support arm 15, which is integral with said inner slide 12, which extends substantially in the direction of said linear guide 11 and which is adapted to support at least one first wheel 16 in such a way that it can rotate about a relative first axis 17, wherein the rolling direction 18 of said at least one first wheel 16 is substantially orthogonal to the direction of said linear guide 11 and parallel to said longitudinal axis A;

[0042] - a second wheel support arm 19, which is integral with said outer slide 13, which extends substantially in the direction of said linear guide 11 and which is adapted to support at least one second wheel 20 in such a way that it can rotate about a relative second axis 21, wherein the rolling direction 22 of said at least one second wheel 20 is parallel to the rolling direction 18 of said at least one first wheel 16.

[0043] - a drive member, which is integral with at least one of said first wheel support arm 16 and said second wheel support arm 19, to rotate at least one of the wheels supported by said at least one of said first wheel support arm 16 and said second wheel support arm 19.

[0044] In the embodiment shown in Figures 6 to 8 , the self-propelled trolley 100 comprises four devices 10, two of which are arranged on the left side of the self-propelled trolley and the other two of which are arranged on the right side of the self-propelled trolley.

[0045] The first wheel 16 has a first axis 17 which is substantially orthogonal to the plane determined by said platform 30 and is provided with said drive member so that it can be rotated to move said self-propelled trolley 100 forwards.

[0046] The second wheel 20 has a second axis 21 substantially parallel to the direction of extension of said linear guide 11, so that the wheel is arranged substantially vertically to support the weight of the self-propelled cart 100.

[0047] With respect to the direction of the longitudinal axis A and therefore with respect to the direction of advancement of said self-propelled cart 100 along the railway track, the platform 30 has a maximum transverse dimension smaller than the dimension of the gauge between the rails R forming said railway track.

[0048] With reference to Figure 9 , said at least one first wheel 16 and at least one second wheel 20 are arranged outside said platform 30 with respect to said transverse direction, so that, after actuation of said outer slide 13 along said linear guide 11, said at least one first wheel 16 and at least one second wheel 20 selectively assume different operating configurations, including at least: a retracted configuration with minimum transverse dimension of said self-propelled cart 100, Figure 9 of a), in which both said at least one first wheel 16 and at least one second wheel 20 are separated from the surface of said rail R; an intermediate first contact configuration, Figure 9 of b), in which said at least one first wheel 16 is in contact with the inner surface of the web G of the rail R, while said at least one second wheel 20 is separated from said rail R; and an extended working configuration, Figure 9 of c), in which said at least one first wheel 16 is in contact with the inner surface of the web G of the rail R with a determined contact force, and said at least one second wheel 20 is in contact with the lower foot plane S of said rail R, said drive member being integral with said first arm 15 to rotate said at least one first wheel 16, while said at least one second wheel 20 is arranged to freely roll on said foot plane S of said rail R.

[0049] The overall vertical dimension of said self-propelled cart 100 is substantially contained within the overall height dimension of said rail R, so that said self-propelled cart 100 can move along said track below the opposite rolling planes.

[0050] The above-mentioned features of the self-propelled cart 100 of the present application and in particular of the preloading and retraction device of the wheel assembly 10 provided in the self-propelled cart 100 are particularly advantageous for speeding up and standardizing the installation operations of installing the self-propelled cart 100 on the track, so that the self-propelled cart can be quickly moved from one track to another, thus optimizing the periodic maintenance operations of the railway vehicles.

[0051] In fact, thanks to the above described structure, the mounting of the self-propelled cart 100 on the track can be performed by activating an actuation member of an external slider 13 of known type not shown, which causes the device 10 to move in a retracted configuration with minimum transverse dimensions, so that the self-propelled cart 100 can be lowered from above between the rails R. When the self-propelled cart is held at a substantially correct mounting height, the movement device of the external slider 13 is actuated to move the external slider 13 outwards along the linear guide 11. Since the external slider 13 and the internal slider 12 are connected by a linear elastic member 14, the movement of the external slider 13 causes the internal slider 12 to move outwards as well, until reaching an intermediate first contact configuration, in which, thanks to the dimensions of the device 10, the first wheels 16 come into contact with the inner surface of the stem G of the rail R, while the second wheels 20 are still separated from the rail R itself. The external slider 13 continues to be actuated outwards until the second wheels carried by this external slider come into contact with the lower foot plane S of the rail R, where the internal slider 12 remains stationary thanks to the abutment of the first wheels 16, but the thrust of the first wheels 16 against the stem G is increased thanks to the loading of the elastic member 14, which in this case comprises a traction coil spring which stretches as the internal slider 12 and the external slider 13 move away.

[0052] Therefore, the actuation of the device 10 allows to pass from a configuration with minimum overall dimensions, which allows to introduce the self-propelled cart 100 into the work area, to a work configuration in which the device 10 brings the opposite wheels into contact with the surface on which they are to roll, also thereby causing the self-propelled cart 100 to automatically centre itself in the confined work environment.

[0053] With regard to what has been illustrated above, modifications and variations to both the preloading and retraction device of the wheel assembly according to the present application and to the entire self-propelled cart can of course be envisaged according to specific functional or application requirements, while remaining within the protection scope provided by the attached claims.

[0054] These variants and modifications can of course be considered as equivalent solutions and are therefore equally protected by the claims.

Claims

1. A preloading and retracting device (10, 10') of a wheel assembly, characterized in that, The preloading and retraction device comprises: - a linear guide (11), - an inner slide (12) which is free to move along the linear guide (11), - an outer slide (13) which is controlled to move along the linear guide (11), - an elastic member (14) which is arranged to connect the inner slide (12) and the outer slide (13) to each other to prevent the relative movement of the inner slide (12) and the outer slide (13) away from or towards each other with respect to a defined natural length distance, - a first wheel support arm (15) which is integral with the inner slide (12), which extends substantially in the direction of the linear guide (11) and which is adapted to support at least one first wheel (16) in such a way that it is rotatable about a relative first axis (17), wherein the rolling direction of the at least one first wheel (16) is substantially orthogonal to the direction of the linear guide (11); - a second wheel support arm (19) which is integral with the outer slide (13), which extends substantially in the direction of the linear guide (11) and which is adapted to support at least one second wheel (20) in such a way that it is rotatable about a relative second axis (21), wherein the rolling direction of the at least one second wheel (20) is parallel to the rolling direction of the at least one first wheel (16).

2. A preloading and retracting device (10, 10') of a wheel assembly according to claim 1, characterized in that, The preloading and retraction device comprises a preloading adjustment member which is placed between at least one of the outer slide (13) and the inner slide (12) and the elastic member (14) to adjust the distance between the inner slide (12) and the outer slide (13) in the natural length condition of the elastic member (14).

3. The preloading and retracting device (10, 10') of a wheel assembly according to claim 1, characterized in that, The preloading and retraction device comprises a drive member which is integral with at least one of the first wheel support arm (15) and the second wheel support arm (19) to rotate at least one of the wheels supported by the at least one of the first wheel support arm (15) and the second wheel support arm (19).

4. A preloading and retracting device (10, 10') of a wheel assembly according to claim 3, characterized in that, The drive member is integral with the first wheel support arm (15) to rotate the at least one first wheel (16) and comprises an electric motor (24), a pulley or toothed wheel (25) which is coaxial and integral with the at least one first wheel (16) and a transmission belt (26) which is located between the pulley or toothed wheel (25) and the drive shaft of the electric motor (24).

5. Self-propelled cart of the type suitable for moving in a confined space between two substantially facing guide surfaces, comprising: - a platform (30), and - a support and movement means by means of wheels, characterized in that said support and movement means by means of wheels comprise at least two preloading and retraction means (10, 10') of a wheel assembly of said support and movement means, said preloading and retraction means (10, 10') being mounted on said platform (30) in a mirror-like manner with respect to a longitudinal axis (A) of said platform (30) which defines a direction of advancement of said platform (30) itself, each of said preloading and retraction means (10, 10') comprising: - a linear guide (11) anchored to said platform (30) so as to extend in the plane of said platform in a direction substantially orthogonal to said direction of advancement of said self-propelled cart, - an inner slide (12) freely movable along said linear guide (11), - an outer slide (13) controllably movable along said linear guide (11), - an elastic member (14) arranged to connect said inner slide (12) and said outer slide (13) to each other so as to prevent a relative movement of said inner slide (12) and said outer slide (13) moving away or approaching with respect to a defined natural length distance, - a first wheel support arm (15) integral with said inner slide (12), said first wheel support arm (15) extending substantially in the direction of said linear guide (11) and suitable to support at least one first wheel (16) in such a way as to enable a rotation of said at least one first wheel (16) about a relative first axis (17), wherein the rolling direction of said at least one first wheel (16) is substantially orthogonal to the direction of said linear guide (11) and parallel to said longitudinal axis (A); - a second wheel support arm (19) integral with said outer slide (13), said second wheel support arm (19) extending substantially in the direction of said linear guide (11) and suitable to support at least one second wheel (20) in such a way as to enable a rotation of said at least one second wheel (20) about a relative second axis (21), wherein the rolling direction of said at least one second wheel (20) is parallel to the rolling direction of said at least one first wheel (16). - a drive member integral with at least one of said first wheel support arm (15) and said second wheel support arm (19) to rotate at least one wheel supported by said at least one of said first wheel support arm (15) and said second wheel support arm (19).

6. The self-propelled cart of claim 5, wherein, Said at least one first wheel (16) has a first axis (17) substantially orthogonal to the plane determined by said platform (30) and is provided with said drive member so that said at least one first wheel (16) can be rotated to move said self-propelled cart forward / backward.

7. The self-propelled cart of claim 5 or 6, wherein, Said at least one second wheel (20) has a second axis (21) substantially parallel to the direction of extension of said linear guide (11) so that said at least one second wheel (20) is arranged substantially vertically to support the weight of said self-propelled cart.

8. The self-propelled cart of claim 7, wherein, The type of said self-propelled cart is adapted to move along a railway track for inspecting the underbody of a railway vehicle, said platform (30) having a maximum transverse dimension smaller than the dimension of the gauge between the rails (R) forming said railway track with respect to the direction of said longitudinal axis (A) and therefore with respect to the direction of said advancement of said self-propelled cart along the railway track, said at least one first wheel (16) and said at least one second wheel (20) being arranged outside said platform (30) with respect to the transverse direction so that, after actuating said outer slide (13) along said linear guide (11), said at least one first wheel (16) and said at least one second wheel (20) selectively assume different operating configurations including at least: a retracted configuration with the minimum transverse dimension of said self-propelled cart, in which both said at least one first wheel (16) and said at least one second wheel (20) are separated from the surface of said rails (R); an intermediate first contact configuration in which said at least one first wheel (16) is in contact with the inner surface of the web (G) of the rails (R) while said at least one second wheel (20) is separated from said rails (R); and an extended working configuration in which said at least one first wheel (16) is in contact with the inner surface of the web (G) of said rails (R) with a determined contact force and said at least one second wheel (20) is in contact with the upper rail foot plane (S) of said rails (R), said drive member being integral with said first wheel support arm (15) to rotate said at least one first wheel (16) while said at least one second wheel (20) is arranged to roll freely on said upper rail foot plane (S) of said rails (R), the overall vertical dimension of said self-propelled cart being substantially contained within the overall height dimension of said rails (R) so that said self-propelled cart can move along said railway track below the track rolling surface.

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