Dolly with pivotable traction module
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-05
- Publication Date
- 2026-08-13
Smart Images
Figure CA2026050182_13082026_PF_FP_ABST
Abstract
Description
DOLLY WITH PIVOTABLE TRACTION MODULECROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The application claims the priority of U.S. provisional patent application no.63 / 754,768, filed on February 6, 2025, and U.S. provisional patent application no.63 / 919,021, filed on November 17, 2025, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD
[0002] The application relates generally to dollies and, more particularly, powered dollies for transporting heavy objects.BACKGROUND OF THE ART
[0003] Equipment carriers, also known as dollies, industrial skates or motorized trolleys are used to lift and / or transport heavy objects in facilities. For instance, heavy objects such as large / cumbersome machineries, containers, etc. may have to be moved in facilities or on sites (e.g. construction sites). Single carriers may be used to move and lift large and heavy objects. Such carriers may be cumbersome as a result of their large dimensions, weight and / or not versatile when it comes to transport equipment of various sizes, geometries, and / or loads. In addition, loss of traction and / or torque transmission between such carriers and the ground during transportation of heavy objects can reduce the carriers performance, such as speed, stability, and maximum payload.SUMMARY
[0004] In one aspect, there is provided a dolly fortransporting a load on a ground surface, the dolly comprising: a frame; a plurality of traction modules, each traction module of the plurality of traction modules pivotally mounted to the frame via a pivot arrangement defining a pivot axis and including: a subframe mounted to the frame via the pivot arrangement, a plurality of rollers mounted to the subframe for pivoting therewith, an actuator unit for driving the plurality of rollers, the actuator unit mounted to the subframe for pivoting therewith, the actuator unit located between the pivot axis and at least anothertraction module of the plurality of traction modules; and an on-board controller unit operable to operate the actuator unit.
[0005] Further in accordance with the above aspect, for example, each traction module includes a drivetrain operatively coupling the actuator unit to the plurality of rollers, the drivetrain configured to transmit a torque of the actuator unit to the plurality of rollers.
[0006] Further in accordance with the above aspects, for example, the pivot axis intersects with at least one roller of the plurality of rollers.
[0007] Further in accordance with the above aspects, for example, the drivetrain is mounted to the subframe for pivoting therewith about the pivot axis.
[0008] Further in accordance with the above aspects, for example, the actuator unit includes a single motor drivingly engaged to the drivetrain, the drivetrain includes a reductor, the reductor and the single motor mounted in parallel with respect to each other.
[0009] Further in accordance with the above aspects, for example, the reductor has a reductor output having a reductor output axis, the single has a motor output having a motor output axis, the motor output axis and the reductor output axis parallel to one another.
[0010] Further in accordance with the above aspects, for example, the motor output axis is parallel with respect to rolling axes of the plurality of rollers.
[0011] Further in accordance with the above aspects, for example, the traction module includes a brake drivingly engaged to the single motor and to the reductor.
[0012] Further in accordance with the above aspects, for example, the drivetrain includes a transmission unit that drivingly interconnects the single motor and the reductor.
[0013] Further in accordance with the above aspects, for example, the brake, the single motor and the reductor are mounted in parallel relative to each other along the transmission unit.
[0014] Further in accordance with the above aspects, for example, the brake, the single motor and the reductor are aligned on a same side of the transmission unit.
[0015] Further in accordance with the above aspects, for example, the transmission unit is a gearbox type of transmission.
[0016] Further in accordance with the above aspects, for example, the actuator unit includes a plurality of motors, the plurality of motors operatively coupled to the drivetrain to provide in unison the torque to the plurality of rollers.
[0017] Further in accordance with the above aspects, for example, the plurality of motors each have a motor output, the drivetrain includes a respective reductor at each motor output of the plurality of motors.
[0018] Further in accordance with the above aspects, for example, the respective reductors at each motor output of the plurality of motors are located between the plurality of motors and the pivot axis.
[0019] Further in accordance with the above aspects, for example, the motor outputs of the plurality of motors extend along a respective motor output axis, the reductors each have a reductor output extending along a respective reductor output axis, the reductor output axes axially aligned with a respective one of the motor output axes.
[0020] Further in accordance with the above aspects, for example, the motor outputs of the plurality of motors have a respective motor output axis, the motor output axes aligned with a rolling axis of a respective one of the plurality of rollers.
[0021] Further in accordance with the above aspects, for example, the reductors at each motor output of the plurality of motors have a reductor output extending along a respective reductor output axis the reductor output axes aligned with a respective one of the motor output axes.
[0022] Further in accordance with the above aspects, for example, the reductors at each motor output of the plurality of motors have a reductor output extending along arespective reductor output axis, the reductor output axes aligned with a respective one of the rolling axes.
[0023] Further in accordance with the above aspects, for example, the plurality of motors, the drivetrain and the plurality of rollers are mounted serially in a direction transverse to the pivot axis.
[0024] Further in accordance with the above aspects, for example, the traction module includes a respective brake operatively coupled to each motor of the plurality of motors, the brakes operable in unison to block a rotation of the plurality of rollers.
[0025] Further in accordance with the above aspects, for example, each brake is operatively coupled to a motor of the plurality of motors between the motor output and a respective one of the reductors.
[0026] Further in accordance with the above aspects, for example, the traction module further includes a plurality of shafts each supporting at least one roller of the plurality of rollers.
[0027] Further in accordance with the above aspects, for example, the plurality of shafts are rotatably supported at opposite ends by the subframe.
[0028] Further in accordance with the above aspects, for example, the plurality of shafts each have a shaft axis, the shaft axes extending transversely with respect to the pivot axis.
[0029] Further in accordance with the above aspects, for example, the drivetrain includes a first main gear and a second main gear drivingly coupled to each other via an intermediary gear, the first gear and the second gear mounted for rotation about a respective gear axis aligned with a respective rolling axis of the plurality of rollers.
[0030] Further in accordance with the above aspects, for example, the pivot arrangement includes a pivot axle, the pivot axle engaging respective portions of the frame and the subframe.
[0031] Further in accordance with the above aspects, for example, the pivot axle is a first pivot axle, the pivot arrangement including a second pivot axle engaging other respective portions of the frame and the subframe, the first pivot axle and the second pivot axle extending coaxially along the pivot axis and supporting one traction module of the pair of traction modules on the frame, the first pivot axle and the second pivot axle located on opposite sides on the subframe.
[0032] Further in accordance with the above aspects, for example, the frame defines a first abutment and a second abutment to restrict a pivoting angle of the subframe with respect to the frame, the subframe pivotable about the pivot axis between a first abutting position and a second abutting position, a portion of the subframe configured to abut against the first abutment in the first abutting position and against the second abutment in the second abutting position.
[0033] Further in accordance with the above aspects, for example, first abutment and the second abutment defined in a recess in the frame, the recess configured to receive the portion of the subframe between the first abutment and the second abutment.
[0034] Further in accordance with the above aspects, for example, the portion of the subframe includes a first surface and a second surface, the first surface and the second surface facing towards the first abutment and the second abutment, respectively.
[0035] Further in accordance with the above aspects, for example, a pivoting angle of the subframe with respect to the frame about the pivot axis is restricted by engagement of the portion of the subframe with the first abutment, in the first abutting position, and the second abutment, in the second abutting position, the pivoting angle from a median position between the first abutting position and the second abutting position, to at least one of the first abutting position and the second abutting position is between 1 degree and 5 degrees.
[0036] Further in accordance with the above aspects, for example, the first surface and the second surface define a tapered end of the portion of the subframe in a direction transverse to the pivot axis.
[0037] Further in accordance with the above aspects, for example, the plurality of motors is a pair of motors.
[0038] In another aspect, there is provided a dolly for transporting a load on a ground surface, the dolly comprising: a frame; a platform extending above the frame; a plurality of traction modules configured for engagement with the ground surface, each traction module of the plurality of traction modules having a subframe pivotally mounted to the frame via a pivot arrangement defining a pivot axis; and a first abutment and a second abutment to restrict a pivoting angle of the subframe, the first abutment and the second abutment integral with the frame, the first abutment and the second abutment defined in a recess in the frame, the recess configured to receive a portion of the subframe, the portion of the subframe configured to engage the first abutment and the second abutment in a first abutting position and a second abutting position, respectively.
[0039] Further in accordance with the above aspect, for example, the pivoting angle is angularly limited by engagement of the portion of the subframe with the first abutment, in the first abutting position, and the second abutment, in the second abutting position, the pivoting angle limited to between ± 1 degrees and ± 5 degrees.
[0040] Further in accordance with the above aspect, for example, each traction module includes a plurality of rollers and an actuator unit for driving the plurality of rollers, the plurality of rollers and the actuator unit mounted to the subframe for pivoting therewith about the pivot axis.
[0041] Further in accordance with the above aspect, for example, the actuator unit is located between the pivot axis of respective ones of the traction modules.DESCRIPTION OF THE DRAWINGS
[0042] Reference is now made to the accompanying figures in which:
[0043] Fig. 1 is a perspective view of a dolly, according to an embodiment;
[0044] Fig. 2 is a top view of the dolly of Fig. 1 ;
[0045] Fig. 3 is a front elevation view of the dolly of Fig. 1;
[0046] Fig. 4 is an exploded perspective view of the dolly of Fig. 1;
[0047] Fig. 5 is a perspective view of a traction module of the dolly of Fig. 1, according to an embodiment;
[0048] Fig. 6 is a top view of the traction module of Fig. 5;
[0049] Fig. 7 is a perspective exploded view of the traction module of Fig. 5;
[0050] Fig. 8 is a schematic view of transmission components of the traction module of Fig. 5;
[0051] Fig. 9 is an elevation view of a part of a frame of the dolly of Fig. 1 , according to an embodiment;
[0052] Figs. 10-11 are partial elevation views of the traction module of Fig. 5 in respective pivoting positions with respect to the frame of the dolly;
[0053] Fig. 12 is a side elevation view of the dolly of Fig. 1;
[0054] Fig. 13 is an exploded view of a dolly, according to a variant;
[0055] Fig. 14 is a perspective view of a traction module of the dolly of Fig. 13;
[0056] Fig. 15 is a top view of the traction module of Fig. 14;
[0057] Fig. 16 is a front elevation view of the traction module of Fig. 14;
[0058] Fig. 17 is a partially exploded view of a drivetrain of the traction module of Fig. 14; and
[0059] Fig. 18 is a bottom perspective view of the traction module of Fig. 14.DETAILED DESCRIPTION
[0060] Figs. 1-4 illustrate a dolly 10 for transporting large loads, The dolly 10 is adapted to displace heavy and / or cumbersome objects, for instance. The dolly 10 may be adapted to transport loads of more than 50 tons, for instance up to 100 tons. The dolly 10 mayform part of a dolly system operable cooperatively to transport large loads, as described in International Patent Application No. PCT / CA2021 / 051695, published as WO2022 / 109745, the entire content of which is incorporated herein by reference.
[0061] The dolly 10 has a frame 100, a platform 200 extending above the frame 100, and traction modules 300 mounted to the frame 100 and adapted to engage the ground surface and drive the dolly 10 on the ground surface. The traction modules 300 are pivotable with respect to the frame 100 to adapt to ground unevenness, e.g., cracks, holes or other types of asperities, debris, etc., and maintain a sufficient level of traction with the ground.
[0062] The frame 100 supports the components of the dolly 10. The frame 100 may be considered as the “skeleton” of the dolly 10. As shown in Fig. 3, the frame 100 is generally planar to keep the dolly 10 compact heightwisely. While it is desirable to have a ground clearance under the frame 100, it is also desirable to maintain the carried load at a minimum elevation above the ground surface during transportation to limit instabilities during displacement (e.g., tilting of the load). As such, the overall height of the dolly 10 is desirably low to keep the load close from the ground surface during transportation with the dolly 10.
[0063] The platform 200 defines a load transmission path between the load and the frame 100. The load supported by the dolly 10 may entirely be received by the platform 200. A total height of the dolly 10 may be defined between a top of the platform 200 and a ground engaging surface of the traction modules 300.
[0064] The traction modules 300 provide traction to the dolly 10 on the ground surface and are configured to drive the dolly 10. The traction modules 300 can be preassemble and mounted to the frame 100 as a standalone module. The traction modules 300 may be easily installed on and removed from the frame 100, for maintenance or replacement, for example. As can be seen from the figures and further described later, the traction modules 300 are partially enclosed within the frame 100, for robustness and compactness of the design. The spatial arrangement of the components of the traction modules 300 is made so as to maximize the trackwidth of the dolly 10 relative to its overall width, for compactness. The actuator units (described later) are also positioned so as tolimit collision therewith with surrounding objects. The traction modules 300 can be operated individually or simultaneously, depending on the control logic and / or desired movements to induce to a carried load.
[0065] The dolly 10 may be controlled wirelessly, though wired communication could be contemplated even though less convenient. A controller unit 400, on the basis of speed, angles, and / or loads measurements acquired from the dolly 10, may control the movement of the dolly 10 by controlling, at least, functions of the traction modules 300.
[0066] Features and components of the frame 100, platform 200, traction modules 300 and controller unit 400 will now be further described.
[0067] The frame 100 provides the rigidity to support the carried load. The frame 100 is adapted to limit bending and / or deflection when the carried load is supported thereon. Referring to Fig. 4, the frame 100 includes a body 110 and beams 120 coupled to the body 110. The body 110 may be centrally located on the frame 100 (sidewise). As shown, the body 110 includes a bearing seat 111. In the embodiment shown, the bearing seat 111 is defined in a recess 112 of the body 110. The body 110 is plate-like. Ribs or other reinforcing features can be contemplated to provide stiffness to the body 110 and / or limit deflection / bending of the body 110 upon loading the dolly 10 with heavy objects.
[0068] In an embodiment, the frame 100 includes beams 120, which span transversely with respect to the front-rear orientation and / or median plane MP (Figs. 2-3) of the dolly 10. As shown, the beams 120 are substantially longer than their cross-sectional dimensions. In the embodiment shown, the beams 120 are main components of the frame 100 that provide the structural rigidity and integrity to the dolly 10. They are designed to be rigid enough to limit deformations (e.g. bending) of the frame 100 in spite of heavy loads that can be supported and transported by the dolly 10. In the depicted embodiment, the beams 120 are spaced apart and joined by the body 110 centrally located within the frame 100. The load from the carried load is transmitted from the body 110 and shared between the beams 120. In the embodiment shown, the beams 120 span on opposite sides of the body 110. The beams 120 are connected at a front end and a rear end of the body 110. The beams 120 may be referred to as front and rear beams 120F, 120R. The beams 120 can define front and rear ends of the frame 100. The body 110 and the beams120 can be mechanically coupled, such as by fasteners. In the embodiment shown, and better seen in Fig. 9, the beams 120 may have a recess 121 sized to receive an end (front / rear) of the body 110. Slide fit tolerance for the sizing of the recess 121 with respect to the ends of the body 110 is one option, but not the only one. Such recess 121 may provide a better interface for load transmission between the body 110 and the beams 120. Such recess 121 is optional.
[0069] In at least some embodiments, the body 110 and beams 120 can be formed together as an integral part. These components of the frame 100 as an integral part may optimize the payload per kilogram of the dolly 10 in at least some embodiments. One continuous piece of material may reduce the stresses and strains concentrations within the frame 100, which may in turn increase its loading capacity and / or compactness. Such an integral part can be formed from a single block of material, which may be machined (e.g., material removal manufacturing techniques), made from additive manufacturing techniques, forging, etc.. Aluminium, steel or titanium are some possible materials for the frame 100. The beams 120 are plain beams, which could be machined from a single block of material (e.g., material removal manufacturing techniques), or made from additive manufacturing techniques, forging, etc., as some possibilities. While referred to as beams 120, such components could be referred to as rods or bars.
[0070] An enclosure 122 is defined between the body 110 and the beams 120 to receive components of the traction modules 300. The body 110 and the beams 120 can surround, at least partially, the enclosure 122. The body 110 and the beams 120 can delimit respective sides of the enclosure 122, here front, rear and top. A belly plate 123 may be coupled, e.g., removably, to the frame 100 (e.g., the body 110, the beams 120, or both) to cover an underside of the dolly 10. The belly plate 123 may close at least partially an underside of the enclosure 122. The belly plate 123 may protect the actuator units (described later) of the traction modules 300 from underneath. The enclosure 122 may be said to be partial, in that it is not fully closed or it does not fully enclose the empty volume that it defines and configured to receive moving components of the traction modules 300 therein.
[0071] The dolly 10 has a casing 124 separate from the enclosure 122 described above. The casing 124 is configured to receive a battery or battery pack BP, the controller unit 400, and other electrical components of the dolly 10 (e.g., wireless communication components, power management, driving / steering control components, wires, etc.). In an embodiment, the casing 124 is located between a portion of the belly plate 123 extending beyond the rear beam 120R and a top cover 125. The top cover 125 may be coupled, e.g., removably, to the rear beam 120R (or front beam 120F) and / or the belly plate 123. The casing 124 may thus be separated from the enclosure 122 by the beam 120R. As seen in Fig. 12, the casing 124 is not enclosed within the enclosure 122. In other words, in the embodiment shown, the casing 124 is located outside of the volume defined between the beams 120.
[0072] Returning to Fig. 4, the beams 120 have connecting portions 130 at their respective ends to cooperate with and receive parts of respective ones of the traction modules 300. The connecting portions 130 include a recess 131 in a side of the beams 120 that face the other one of the beams 120. The recess 131 is defined between opposing surfaces 131 A, 131 B. A surface 132 extending transversely between the opposing surfaces 131 A, 131 B may face towards a corresponding surface of the other beam 120. As shown, the recesses 131 oppositely face each other on opposite sides of the enclosure 122 of the frame 100. The recesses 131 in the beams 120 are configured to receive, respectively, an end portion of a traction module 300. The recesses 131 may have a generally U-shape opened towards lateral side ends of the frame 100. The end portions of the traction modules 300 may be inserted into the respective recesses 131 by lateral engagement with the frame 100, in a direction normal to the median plane MP of the frame 100. A bore 134 is defined at an end of the beam 120. The bore 134 may be a throughbore across a thickness of the beam 120, as shown. The bore 134 of each beam 120 at their corresponding ends are coaxial. Such bores 134 form parts of a pivot arrangement to pivotally mount a traction module 300 to the frame 100, as will be described later. As shown, both ends of the beams 120 can have corresponding features to receive and mount the respective traction modules 300. Both ends of the beams 120 could be identical or not, depending on embodiments. Features of the traction modules 300 and how they cooperate with the frame 100 will be further described later.
[0073] The platform 200 extends above the frame 100. The platform 200 defines a load transmission path between the load and the frame 100. In at least some embodiments, the platform 200 projects upwardly from the frame 100 so as to define a clearance between a top of the frame 100 and the load supported by the platform 200. The platform 200 may define a load contacting surface 201. The load may be directly contacting such surface 201, in at least some cases. Blocks or other intermediary components between the platform 200 and the load may be used to elevate the load higher above the ground surface for displacement, if desired. In at least some embodiments, as shown, the platform 200 is pivotable about a platform axis Z. The pivoting of the platform 200 may be via bearing 202 (orbearing assembly). The dolly 10 may rotate about the platform axis Z with respect to the ground surface and its carried load, without moving the load. This may allow a change of orientation of the dolly 10 with respect to the ground surface to orient its traction modules 300 in a desired travel direction, without inducing any movement to the carried load. In the embodiment shown, the platform 200 intersects with a median plane MP of the frame 100. The platform axis Z may be aligned with the median plane MP. Locating the platform 200 centrally with respect to the trackwidth / wheelbase of the folly 10 may increase stability, reduce a likelihood of dolly tilting, and / or provide a more balanced sharing of the load on the rollers (described below) of traction modules 300. In the depicted embodiment, the platform 200 defines the only point of contact between the dolly 10 and the object to be displaced. Other configurations could permit otherwise without substantially hindering the rotation of the dolly 10 with respect to the object to be displaced.
[0074] Referring to Figs. 5 to 8, the traction module 300 will now be further described.
[0075] The traction module 300 includes a frame, which will be referred to as a subframe 310 here to avoid confusions with the frame 100. The subframe 310 is mounted to the frame 100 via a pivot arrangement 320. The pivot arrangement 320 defines a pivot axis 321. The subframe 310 can pivot about the pivot axis 321. In the embodiment shown, the subframe 310 includes frame members, here plates that are coupled together (e.g., fasteners). The subframe 310 in the embodiment shown has a generally rectangular outline. The subframe 310 as a front end 31 OF and an opposite rear end 31 OR. Side ends 310S1, 310S2 extend between the front and rear ends 31 OF, 31 OR. As can be seen inFig. 7, the subframe 310 includes a bore 324, adapted to receive a pivot axle 325. Fig. 6 shows that such configuration can be mirrored at the front and rear ends 31 OF, 31 OR of the subframe 310. To assemble the traction module 300 on the frame 100, the traction module 300 can be inserted laterally into the frame 100 on a side thereof. The bores 324 of the traction modules 300 and that of the beams 120 can be aligned to allow insertion of pivot axles 325 therein. Once the pivot axles 325 are in place, the subframe 310 can be pivotally secured on the frame 100. The pivot axles 325 can be retained in the bores 324 via snap rings, or other fasteners. The pivot arrangement 320 pivotally coupling the traction module 300 to the frame 100 may thus include a first and a second pivot axles 325 engaging respective portions of the frame 100 and the subframe 310. The first pivot axle 325 and the second pivot axle 325 may extend coaxially along the pivot axis 321 and support one traction module 300 of the pair of traction modules 300 on the frame 100. The first pivot axle 325 and the second pivot axle 325 are located on opposite sides on the subframe 310, here front and rear ends thereof. In the embodiment shown, the pivot axis 321 extends in a front-rear orientation with respect to the dolly 10. The traction modules 300 may thus pivot from side to side (roll movement of the traction module 300 with respect to a driving direction). The subframe 310 defines a central opening 311 (or simply opening) surrounded by its front, rear and side ends. The central opening 311 is configured to receive rollers 312 of the traction module 300. As shown, the pivot axis 321 intersects with the central opening 311. Stated otherwise, the central opening 311 defines an area in which rollers 312 are received and the pivot axis 321 extends through such area. The pivot axis 321 may extend through a space defined between a top of the rollers 312 and a ground contact interface between the rollers 312 and the ground. In at least some embodiments, as shown, the pivot axis 321 intersects with at least one roller 312 of the plurality of rollers 312. In alternate embodiments, the pivot axis 321 could extend between adjacent rollers 312.
[0076] In at least some embodiments, the rollers 312 are supported by shafts 313. The shafts 313 are mounted for rotation to the subframe 310, about a rolling axis 314. The rollers 312 and the shafts 313 can thus pivot with the subframe 310 about the pivot axis 321. In at least some embodiments, the shafts 313 can be rotatably supported at opposite ends by the subframe 310, for example via bearings. As shown, the shafts 313 have a shaft axis 315 that extends transversely with respect to the pivot axis 321. In anembodiment, the shafts 313 and / or shaft axes 315 may intersect with the pivot axis 321. Each shaft 313 can support at least one roller 312. The rollers 312 can be a cylindrical roller. Spherical rollers, or rollers with a varying diameter could be contemplated. There can be a plurality of rollers 312 on a same shaft 313. In at least some embodiments, as shown, the rollers 312 do not have the same hardness. In some embodiments, the outwardmost roller 312 on a shaft 313 has a lower hardness than one or more other rollers 312 on the same shaft 313. The lower hardness may provide better grip on the ground surface. The other rollers 312 may have a higher hardness to limit deformation caused by the heavy loads carried by the dolly 10. In an embodiment, the rollers 312 may be made of polyamid (e.g., nylon) or polyurethane. The polyurethane ones are generally more deformable than the polyamid ones, and can provide more grip on the ground surface. A combination of polyamid and polyurethane rollers 312 can thus be contemplated to benefit from both, in the configuration explained above. In some embodiments, the outwardmost roller 312 could have a larger diameter than one or more other rollers, to shift more load thereon and maximize floor contact therewith. All rollers 312 could have the same configuration, dimensions or made of the same material, in variants. The rollers 312 may directly contact the ground surface or, in variants, indirectly, for example by interfacing with a track, belt, or other ground contacting means.
[0077] The actuator unit 330 is mounted on a side end 310S1 of the traction module 300. The actuator unit 330 is configured to drive the plurality of rollers 312 of the traction module 300. The actuator unit 330 is mounted to the subframe 310 and can pivot therewith about the pivot axis 321. Having the actuator unit 330 pivotable with the subframe 310 can simplify the power transmission configuration and mechanical connection between the actuator unit 330 and drivetrain 340 (described later). As can be seen from Fig. 1 , the actuator unit 330 of each traction module 300 is located between the pivot axis 321 of respective ones of the traction modules 300 of the pair of traction modules 300. Having the actuator unit 330 close from the centre of the dolly 10 and enclosed in the enclosure 122 can better protect them from surrounding objects and / or impacts. Such inward position of the actuator unit 330 relative to the rollers 312 can also help in maximizing the track width of the dolly 10 with respect to its total width.
[0078] In the embodiment shown, the actuator unit 330 includes a plurality of motors 331. The motors 331 can provide in unison their torque to the rollers 312, via the drivetrain 340 (described below). The motors 331 can be servomotors, to allow precise control and avoid / limit jerk. In some embodiments, there may be a single servomotor per traction module 300, and other types of motors 331 that are not servomotors. Each motor 331 has a motor output 332. The motor outputs 332 can be male or female outputs, e.g., shaft, bore to receive a shaft, etc.). The motor outputs 332 have a respective motor output axis 333. In the embodiment shown, the motor output axes 333 are axially aligned with a respective rolling axis 314 of the rollers 312. The rolling axes 314 and the motor output axes 333 may be coaxially aligned in at least some embodiments. The motors 331 work in tandem. In operation, all motors 331 can be powered to generate torque. Their respective torque can be transmitted to the rollers 312 via the drivetrain 340. The motors 331 can be identical (in size, capacity, model) or different. For example, one of the motors 331 could be more powerful than the other. The motors 331 may generate an unequal amount of torque, for example, and still provide their combined torque to the rollers 312 via the drivetrain 340.
[0079] The drivetrain 340 operatively couples the actuator unit 330 to the plurality of rollers 312. The drivetrain 340 is configured to transmit a torque of the actuator unit 330 to the plurality of rollers 312. In at least some embodiments, as shown, the drivetrain 340 is configured to be operatively coupled to the motors 331 of the actuator unit 330 to transmit the torque from a plurality of motors 331 (here two) to the plurality of rollers 312. The total required torque at the rollers 312 to displace the dolly 10 with its carried load can thus be split between the motors 331. Stated otherwise, the motors 331 may be sized to generate a fraction of the total required torque at the rollers 312 to displace the dolly 10 with its carried load. By using motors 331 with lower torque capacity as part of the actuator unit 330 and providing torque in unison to the rollers 312 via the drivetrain 340, instead of having a single motor 331 , for example, to generate all the torque required at the rollers 312, the size / dimensions of the motors 331 can be more limited. This can provide greater compactness to the dolly 10 as a whole, while still allowing to generate sufficient torque to displace heavy loads (e.g., more than 50 tons) at a relatively high speed. The ratio payload over dimension of the dolly 10 can thus be increased compared to other dollies relying on a single source to produce torque to rollers, yet still provide arelatively high speed considering the size and load of the object to be carried compared to the size and load of the dolly 10. In an embodiment, for example, a total height of the dolly 10 may be 185 mm (7,25 inches) for a payload of between 50 tons and 70 tons.
[0080] As shown, the drivetrain 340 is mounted to the subframe 310. The drivetrain 340 may thus pivot with the subframe 310, about the pivot axis 321. In the embodiment shown, the drivetrain 340 can transmit torque to the shafts 313 that support the rollers 312. The transmitted torque can be split between the shafts 313, in the configuration shown. In an embodiment, the drivetrain 340 includes a respective reductor 341 at each motor output 332. Reductors 341 have a torque capacity that can be impacted by its overall size / dimensions. Reductors 341 can thus be viewed as a limiting factor when compactness and power-to-size ratio of the dolly 10 are important. For example, larger torque capacity for a reductor may often come with a size increase of the reductor. This would translate in an increase in size of the dolly 10 (e.g., heightwise). Splitting the power generation between more than one motor 331 and transmitting the torque from motors 331 via respective reductors 341 of smaller size - compared to a single larger reductor -can assist in keeping smaller overall dimensions of the dolly 10 (here at least in terms of height). In at least some embodiments, such as shown, the respective reductors 341 at each motor output 332 are axially located between the plurality of motors 331 and the pivot axis 321 of the traction module 300. As mentioned above, the motor outputs 332 may extend along a respective motor output axis 333. In at least some embodiments, the reductors 341 each have a reductor output 342 extending along a respective reductor output axis 343. The reductor output axes 343 may be axially aligned with a respective one of the motor output axes 333. In some cases, the reductor output axes 343 and the motor output axes 333 may be coaxial (though this is optional, in at least some embodiments). In at least some embodiments, the reductor output axes 343 (or at least one thereof) may be axially aligned with a respective one of the rolling axes 314. The reductor output 342 can be a male or female output, such as a shaft, a pin, a tube, a bore to receive a shaft / pin, for example.
[0081] In at least some embodiments, such as shown, the motors 331 , the drivetrain 340, and the rollers 312 are mounted serially in a direction transverse to the pivot axis 321. As shown, a transverse plane TP of the subframe 310 can intersect with the motors 331,the drivetrain 340, and the rollers 312, in such serial arrangement. In an embodiment, such transverse plane TP may intersect with the pivot axis 321 about which the traction module 300 can pivot, though this is optional. In some embodiments, the motor output axes 333, the reductor output axes 343 and the rolling axes 314 may all extend within such transverse plane TP, though this is optional. In an embodiment, the motors 331, the drivetrain 340 (reductors 341 and other drivetrain components), and the rollers 312 may all fit within parallel planes extending between the ground surface (e.g., ground contacting plane into which are the roller contact points with the ground) and a top of the subframe 310 of the traction module 300, and / or a top of the frame 100 (e.g., top of the beams 120) of the dolly 10. Such configuration may allow to limit a distance between the rollers 312 and the carried load on top of the dolly 10, maintain the carried load at a lower elevation above the ground during displacement, and / or reduce the overall heightwise dimension of the dolly 10.
[0082] Referring more particularly to Fig. 7, the traction module 300 includes a brake system that is operatively coupled to the motors 331 and operable to block a rotation of the rollers 312 engaged with the ground. In at least some embodiments, as shown, the traction module 300 has a respective brake 345 operatively coupled to each motor 331. The brakes 345 can be operated in unison to block the rotation of the rollers 312. The brakes 345 may be clutch brakes, such as electromagnetic clutch brakes, or other types of electromagnetic brakes, for example. Pneumatic brakes could be contemplated, as another possibility, or mechanical brake. Each brake 345 may thus be sized based on fraction of the total braking power required for a traction module 300 rather than for the full total braking power required. Splitting the required brake power between separate brakes 345 each mounted to a respective motor 331 can be advantageous also for sizing. In the embodiment shown, each brake 345 is operatively coupled to a respective one of the reductors 341 between such reductor 341 and a motor 331 of the plurality of motors 331. It may be advantageous to couple the brake 345 operatively upstream of the reductors 341 to limit the torque induced to the brake 345 by blocking rotation of the rollers 312 in static friction with the ground. The size / dimension of the brake 345 may thus be reduced, hence the required volume for the brake 345 can be more limited.
[0083] The brakes 345 may be configured to be in "normally close" state. When not powered or activated, the brakes 345 can block rotation of the rollers 312 and, once powered / activated, the brakes 345 can be energized / released to permit rotation. For example, when the brakes 345 are electromagnetic brakes, the brakes 345 can be energized to disengage the brake 345 and permit rotation of the rollers 312. This may be implemented for safety reasons.
[0084] Referring to Figs. 7-8, the drivetrain 340 includes torque transmission components for operatively coupling the motors 331 to the rollers 312 to transmit the combined torque generated by the motors 331 to the rollers 312 that are mounted on different shafts 313. As shown, main gears 346 are drivingly coupled to each other via an intermediary gear 347. The main gears 346 are mounted for rotation about a respective gear axis 348. As shown, the gear axes 348 can be axially aligned with a respective rolling axis 314 of rollers 312. In the embodiment shown, the gears 346 are mounted on respective shafts 313 that support the rollers 312. The gear axes 348, the rolling axes 314 and the shaft 313 may be coaxial. The main gears 346 could be made integral with the shafts, or as separate parts. The main gears 346 may have the same tooth pattern (shape, number of teeth, etc.), though this is optional. The intermediary gear 347 allows to transmit the torque between the two main gears 346. As such, torque generated by one of the motors 331 can be transmitted to all the rollers 312 and shafts 313. A gear ratio between the main gears 346 and the intermediary gear 347 may be, in some embodiments, at least 1.5:1, e.g., between 1.5:1 and 3:1. In the configuration shown, the intermediary gear 347 drivingly couple the main gears 346 such that the rotation of the main gears 346 is in the same direction. However, in operation, it is desirable to have the set of motors 331 providing the torque in unison to combine their respective torque outputs. Control of the actuator unit 330 by the controller unit 400 can allow that, as described later. In variants, the drivetrain 340 could have a chain and pinion configuration instead of the gear assembly shown.
[0085] Because of imperfections, debris, asperities, cracks, etc. on the ground, load transmission between rollers 312 and ground can be uneven (or even absent at some rollers 312 if not providing sufficient contact). The mechanical coupling between the reductors 341 at their outputs 342 are therefore mechanically linked to ensure that powersharing between motors 331 is efficient, and traction is increased. In operation, the torque at one or more reductor outputs 342 can be transmitted to a single shaft 313, when traction between roller(s) 312 on other shaft(s) 313 and the ground is lost or reduced. This may allow to maintain sufficient traction. The reductors 341 may at any time transmit load to all rollers / shaft, via the gear assembly of the drivetrain 340, to provide torque to the roller(s) that require(s) the most. Similarly, the mechanical coupling of the brakes 345 via the gear assembly of the drivetrain 340 can provide the combined braking forces of the brakes 345 to a single shaft 313, when traction between rollers 312 on other shaft(s) 313 and the ground is lost or reduced. The brakes 345, although axially coupled between their respective motors 331 and reductors 341 , can work in tandem to generate braking force to the traction module 300.
[0086] In variants, the actuator unit 330 could include more motors 331 than a pair of motors 331. For example, there could be twice the number of motors 331 per shaft to be driven. There could be more shafts 313 per traction module 300 instead of the configuration shown. For example, a variant of the traction module 300 could have three, or four shafts, for example, with a corresponding increased number of roller sets. There could be a corresponding increase in motors 331 , though there could be less motors than shafts 313 in such variants to maintain compactness of the dolly 10, as long as sufficient total power is obtained to displace the loads. In variants, there could be a single motor per traction module 300 as described herein later.
[0087] The relatively planar configuration of the traction modules 300, with their actuator unit 330 and drivetrain 340 mounted generally axially may provide greater modularity of the traction modules 300, and limit their overall height, which may be, as mentioned herein, an important aspect for a dolly 10 configured to carry heavy and cumbersome objects at the lowest possible elevation above the ground.The traction modules 300, while pivotable with respect to the frame 100, may have a limited pivoting angle. The pivoting angle of the subframe 310 with respect to the frame 100 about the pivot axis 321 may be restricted by engagement of at least one portion of the subframe 310 with the frame 100. Referring to Figs. 9-11, the surfaces 131 A, 131B of the recess 131 in the frame 100 can define respective abutments engageable by thesubframe 310 when the subframe 310 reaches a maximum pivoting angle. The subframe 310 is pivotable about the pivot axis 321 between a first abutting position and a second abutting position, shown in Figs 10-11 respectively. In an embodiment, the pivoting angle from a median position between the first abutting position and the second abutting position, to at least one of the first abutting position and the second abutting position is between 1 degree and 5 degrees. The pivoting angle could be limited to between ± 1 degree and ± 3 degrees. In a particular embodiment, the pivoting angle is limited to ± 1.5 degrees.
[0088] The recess 131 is configured to receive a respective portion of the subframe 310 between the first and second abutments defined by the surfaces 131A, 131 B. Such portion of the subframe 310 is located at the front end or rear end 31 OF, 31 OR of the subframe 310. Such portion of the subframe 310 is configured to abut against the first abutment in the first abutting position and against the second abutment in the second abutting position. As shown, the subframe 310 includes a first surface 310A and a second surface 310B, the first surface 310A and the second surface 310B facing towards the first abutment and the second abutment, respectively. In at least some embodiments, the first and second surfaces 310A, 310B define a tapered end of the portion of the subframe 310 in a direction transverse to the pivot axis 321. The taper can facilitate the sidewise insertion of the subframe 310 in the recesses 131, during installation of the traction module 300 on the frame 100. The tapered surfaces 310A, 310B may also provide a greater contact area between the subframe 310 and the surfaces 131 A, 131 B for abutment. This may result in a better load transmission, and more robustness, even when loads applied to the abutments can be quite large due to the load of the carried objects.
[0089] While such abutments and pivoting angle limiter have been described with respect to a single end of the subframe 310, it should be understood that it equally applies to both ends. The abutment arrangement can be mirrored at rear / front end of the traction module 300 and correspondingly facing sides of the beams 120.
[0090] Based on the above, a dolly 10 for transporting a load on a ground surface can comprises a frame 100, a platform 200 extending above the frame 100, a pair of traction modules 300 configured for ground engagement with the ground surface and drive the dolly 10. Each traction module 300 of the pair of traction modules 300 can have asubframe 310 pivotally mounted to the frame 100 via a pivot arrangement 320 defining a pivot axis 321. A first abutment and a second abutment may restrict a pivoting angle of the subframe 310. In at least some embodiments, the first abutment and the second abutment are integral with the frame 100. In at least some embodiments, the first abutment and the second abutment are defined in a recess 131 in the frame. In at a least some embodiments, the recess 131 is configured to receive a portion of the subframe 310. The portion of the subframe 310 is configured to engage the first abutment and the second abutment in a first abutting position and a second abutting position, respectively.
[0091] The dolly 10 may be controlled wirelessly, though wired communication could be contemplated even though less convenient. A controller unit 400, on the basis of speed, angles, and / or loads measurements acquired from the dolly 10, may control the movement of the dolly 10. The controller unit 400 may be operatively connected to the various motors / actuators of the dolly 10. The controller unit 400 may include one or more processing units and transitory computer-readable memory communicatively coupled to the processing unit(s) and comprising computer-readable program instructions executable by the processing unit(s) for operating the dolly 10 in the manner described herein. The controller unit 400 can be an on-board controller unit that is operable to operate the actuator unit 330, drivetrain 340, brake system, etc.. In an embodiment, the controller unit 400 may have a remote user interface communicatively coupled with the controller unit 400. The remote user interface may be a handheld device that is manually operable to select operating modes, start, stop and / or control the displacement of the dolly 10 with or without transported loads. Other types of user interface could be contemplated, e.g., self-standing user interface, wired or wireless. The controller unit 400, or part thereof, could be embedded into the user interface in variants. In at least some embodiments, at least one motor 331 of the plurality of motors of a traction module 300 is a servomotor. All motors 331 of the traction module 300 could be servomotors in some embodiments. Actuating signals may be sent to the servomotors as speed and / or direction signals. Other types of input signals may be contemplated, e.g., torque signals. During operation of the dolly 10, speed of the dolly 10 may be measured via the servomotors, for instance via processing of angular increments of the servomotors, e.g. by the controller unit 400 (described later). Such measured speed may serve in a control loop of the controller unit 400 to drive the dolly 10 in a desired path / displacement. In anembodiment, one of the motors (e.g., a servomotor) may be controlled and referred to as the master motor that is speed-controlled while one or more other motors of the same traction module 300 can be controlled or referred to as slave motor(s) that is / are torque controlled based on a torque feedback from the master motor, e.g., via the controller unit 400. As such, in some embodiments, there may be a single servomotor per traction module 300 with one or more other motors mechanically coupled therewith being motors without encoder (e.g., brushless motors).
[0092] In variants, the dolly 10 could have more than two traction modules 300. For example, the dolly 10 could have more than one pair of traction modules 300. There could also be a plurality of traction modules 300, whether or not in pairs.
[0093] A variant of the dolly 10 will now be described with reference to Figs. 13- 18. Like features will bear corresponding primed reference numbers for ease of reference and will not be described herein in duplicate. The description of the elements with reference to Figs. 1-12 described above similarly applies to the features of the variant of the dolly 10’ shown in Figs. 13-18 and they will not be repeated in entirety for brevity.
[0094] Fig. 13 shows a dolly 10’ with a frame 100’, a platform 200’ extending above the frame 100’, and traction modules 300’ mounted to the frame 100’ and adapted to engage the ground surface and drive the dolly 10’ on the ground surface. The traction modules 300’ are pivotable with respect to the frame 100’ to adapt to ground unevenness, e.g., cracks, holes or other types of asperities, debris, etc., and maintain a sufficient level of traction with the ground.
[0095] The traction modules 300’ provide traction to the dolly 10’ on the ground surface and are configured to drive the dolly 10’. The traction modules 300’ can be preassembled and mounted to the frame 100’ as a standalone module. The traction modules 300’ may be easily installed on and removed from the frame 100’, for maintenance or replacement, for example. As described above with reference to various embodiments, the traction modules 300’ are partially enclosed within the frame 100’, for robustness and compactness of the design. The spatial arrangement of the components of the traction modules 300’ is made so as to maximize the trackwidth of the dolly 10’ relative to its overall width, for compactness. The actuator units 330’ are also positioned so as to limitcollision therewith with surrounding objects. The traction modules 300’ can be operated individually or simultaneously, depending on the control logic and / or desired movements to induce to a carried load.
[0096] An enclosure 122’ is defined between the body 110’ and the beams 120’ of the frame 100’ to receive components of the traction modules 300’. The body 110’ and the beams 120’ can surround, at least partially, the enclosure 122’. The body 110’ and the beams 120’ can delimit respective sides of the enclosure 122’, here front, rear and top. A belly plate 123’ may be coupled, e.g., removably, to the frame 100’ (e.g., the body 110’, the beams 120’, or both) to cover an underside of the dolly 10’. The belly plate 123’ may close at least partially an underside of the enclosure 122’. The belly plate 123’ may protect at least part, of the actuator units 330’, drivetrains 340’ and brakes 345’ of the traction modules 300’ from underneath. The enclosure 122’ may be said to be partial, in that it is not fully closed or it does not fully enclose the empty volume that it defines and that is configured to receive moving components of the traction modules 300’ therein.
[0097] Referring to Figs. 14 and 15, the traction module 300’ includes a frame, which will be referred to as a subframe 310’ here to avoid confusions with the frame 100’. The subframe 310’ is mounted to the frame 100’ via a pivot arrangement 320’. The pivot arrangement 320’ defines a pivot axis 32T. The subframe 310’ can pivot about the pivot axis 32T. The pivot arrangement 320’ pivotally coupling the traction module 300’ to the frame 100’ may thus include a first and a second pivot axles 325’ (Fig. 13) engaging respective portions of the frame 100’ and the subframe 310’. The first pivot axle 325’ and the second pivot axle 325’ may extend coaxially along the pivot axis 32T and support one traction module 300’.
[0098] The subframe 310’ defines an opening 31 T surrounded by its front, rear and side ends. The opening 31 T is configured to receive rollers 312’ of the traction module 300’.
[0099] Referring to Fig. 14, the actuator unit 330’ is mounted on a side end 310S1’ of the traction module 300’. The actuator unit 330’ is mounted to the subframe 310’ and can pivot therewith about the pivot axis 32T. Similarly, the drivetrain 340’ is mounted on the same side end 31 OST of the traction module 300’ and can pivot therewith about the pivot axis 32T. Having the actuator unit 330’ pivotable with the subframe 310’ can simplify thepower transmission configuration and mechanical connection between the actuator unit 330’ and drivetrain 340’ (described later). As can be seen from Fig. 13, the actuator unit 330’ of each traction module 300’ is located between the pivot axis 321’ of respective ones of the traction modules 300’ of the pair of traction modules 300’. Having the actuator unit 330’ close from the centre of the dolly 10’ and enclosed in the enclosure 122’ can better protect them from surrounding objects and / or impacts. Such inward position of the actuator unit 330’ relative to the rollers 312’ can also help in maximizing the track width of the dolly 10’ with respect to its total width.
[0100] In the variant shown, the actuator unit 330’ includes a single motor 331’ (e.g., servomotor) that is drivingly engaged to the rollers 312’ via the drivetrain 340’. The single motor 33T of each traction module 300’ may be controlled independently, or simultaneously. For example, a same set of control instructions can be sent to each motor 33T to cause a displacement of each traction module 300’ with respect to the ground surface. Different instructions may be sent to the motors 33 T as another option. The motor 33T can provide torque to the rollers 312’, via the drivetrain 340’. The motor 33T has a motor output 332’. The motor outputs 332’ can be male or female outputs (e.g., shaft, bore to receive a shaft, etc.). The motor output 332’ has a motor output axis 333’. In the variant shown, the motor output axis 333’ is parallel with respect to a rolling axis 314’ of the rollers 312’. The drivetrain 340’ includes a reductor 34T. The reductor 34T has a reductor output 342’ having a reductor output axis 343’. In the variant shown, the motor output axis 333’ and the reductor output axis 343’ are parallel to one another.
[0101] A braking system of the traction module 300’ includes a brake 345’ drivingly engaged to the motor 33T. The brake 345’, like the motor 33T and the reductor 34T, is mounted to the subframe 310’ and may pivot with the subframe 310’ about the pivot axis 32 T, concurrently with the motor 33 T and the reductor 34 T.
[0102] The reductor 34T is drivingly coupled to the rollers 312 via torque transmission components configured to transmit the torque from the reductor output 342’ to the rollers 312’ that are mounted on the shafts 313’. The torque transmission components in the variant shown can have a similar arrangement as that shown and described with reference to Figs. 7-8. However, in the variant shown, the reductor output342’ may be drivingly couped to the intermediary gear 347’. While the intermediary gear 347 described earlier with reference to Figs. 7-8 is configured to act as a transmission idler (or passive gear) that transmits torque between the two driving gears 346 driven by respective motors 331 and reductors 341 on the respective shafts 313, in the variant shown with reference to Fig. 17, the intermediary gear 347’ may act as the driving gear that receives the torque from the reductor output 342’ to distribute the torque generated by the single motor 33T, between the driven gears 346’ on the respective shafts of the rollers 312’. As shown, the reductor output 342’ may have a keying feature that corresponds to a keying feature of the intermediary gear 347’ for direct coupling between them. This is one possibility among others to transmit the torque from the reductor output 342’ to the rollers 312’, as chain and gears or other gearbox configurations could be contemplated.
[0103] In the variant shown, the drivetrain 340’ includes a transmission unit 344’ that drivingly interconnects the motor 33T, the reductor 34T, and the brake 345’. The motor 33T and the reductor 34 T are mounted in parallel relative to one another on a side of the transmission unit 344’. Likewise, the brake 345’ is mounted in parallel relative to the motor 33T and the reductor 34 T on the side of the transmission unit 344’. All of these components may be mounted on a same side of the transmission unit 344’, as shown. The motor 33T, the reductor 34 T and the brake 345’ may thus be referred to as being in a parallel configuration, as opposed to be stacked axially along a common axis. This configuration may provide more compactness to the traction modules 300’ widthwisely (direction parallel to the rolling axes 314’). A more compact configuration widthwise may also allow more clearance between the moving components of the traction modules 300’ and the frame 100’ of the dolly 10’ as the traction modules 300’ pivot. As the traction modules 300’ pivot about their pivot axes 32T, the motor 33T, reductor 34T and brake 345’ move within the enclosure 122’ of the frame 100’. For a given angular displacement of the traction modules 300’ about their pivot axes 32T, the shorter the motor 33T, reductor 34 T and brake 345’ project from the side end 31 OST of the traction module 300’, the smaller the absolute displacement is at the overhanging end thereof. The increased compactness may also allow to reduce the overall width of the dolly 10’, by bringing the pivot axes 32T closer from the center of the dolly 10’ and / or closer from the platform 200’, thereby increasing the overall compactness of the dolly 10’.
[0104] The disposition of the motor 33T, reductor 34 T and brake 345’ is such that the reductor output 342’ is generally centered on the side end 31 OST of the traction module 300’, with the motor 33T and the brake 345’ disposed on opposite sides thereof. Other configurations could be contemplated in other variants.
[0105] In the variant shown, the motor 33T, the reductor 34T and the brake 345’ are jointly drivingly engaged to the transmission unit 344’. The transmission unit 344’, in the variant shown, is a gearbox type of transmission. Other options could exist, such as a chain(s) and gears arrangement. Referring to Fig. 17, the transmission unit 344’ includes a transmission carter 344A’ that contains gears. The transmission carter 344A’ may define a cavity (or cavities) that contains the gears. A cover 344B’ can sealingly engage the transmission carter 344A’ to enclose the gears. The transmission unit 344’ may include at least three gears G1, G2, G3, namely a firstone (G1) coupled at the motor output 332’ to transmit the driving force from the motor 33T, a second one (G2) coupled at the reductor input 341 A’ to transmit the torque received from the motor 33T via the transmission unit 344’ to the reductor 34T, and a third one (G3) coupled to the brake 345’. Each of these gears G1, G2, G3 may be drivingly interconnected via intermediary gears G4,G5, as shown. In the variant shown, there are the three gears G1, G2, G3 and the intermediary gears G4, G5, which allows to drivingly interconnect the gears G1, G2, G3 of the motor output 332’, the reductor input 341A’ and the brake 345’, while limiting the size of the gears G1, G2, G3, thereby limiting the overall height of the transmission unit 344’. Different ratios between those gears could be contemplated. For example, in a variant, a ratio between the motor output 332’ and the reductor input 341 A’ may be 1.2:1. Other ratios are possible. The gears G1, G2, G3 may be coaxially aligned with their respective motor output 332’, reductor input 341A’ and brake 345’.
[0106] Referring to Fig. 18, the traction module 300’ may have a protective plate 349’, which may be referred to as a belly plate like the belly plate 123’ but will be referred to as protective plate for clarity. The protective plate 349’ is mounted to the subframe 310’ and can pivot therewith about the pivot axis 32T. As shown, the protective plate 349’ is mounted on the same side end 31 OST of the traction module 300’ as the motor 33T, the reductor 34T the transmission unit 344’ and the brake 345’. The protective plate 349’ projects from the side end 31 OST, underneath the motor 33T, the reductor 34T, and thebrake 345’ to pivot therewith about the pivot axis 321’. The protective plate 349’ may project underneath the transmission unit 344’ as well in some variants. The protective plate 349’ may follow the pivoting movement of the traction module 300’ and interface between the ground and the components listed above. The protective plate 349’ may cooperate with the belly plate 123’ (Fig. 13) so as to close a majority of the enclosure 122’ from underneath. The protective plate 349’ may be viewed as a moving section of the belly plate 123’ that can displace jointly with the traction module 300’ in its pivoting movement. When the dolly 10’ is on a horizontal and even surface (or plane), e.g., when the pivoting angle of the traction module is null with respect to a horizontal plane, a projecting end of the protective plate 349’ may be generally aligned with a side edge of the belly plate 123’ to form a substantially continuous physical barrier between the motor 33T, the reductor 34T the transmission unit 344’ and the brake 345’ and the ground. As the traction module 300’ pivots, the projecting end of the protective plate 349’ may angularly displace (e.g., displace up and / or down) with respect to the side edge of the belly plate 123’, without interfering therewith. A gap between the projecting end and the side edge of the belly plate 123’ may allow the transmission unit 344’ to clear the belly plate 123’ as the transmission unit 344’ moves up and / or down relative to the belly plate 123’ as the traction module 300’ pivots. Such gap may be sized to allow movement of the transmission unit 344’ adjacent the side edge of the belly plate 123’, without interfering therewith. In some variants, the protective plate 349’ and / or the belly plate 123’ may extend under the transmission unit 344’ to fully enclose the transmission unit 344’ over the entire range of angular movement of the traction module 300’. Rigidifying members 349A’ may extend from the protective plate, as an integral part thereof or assembled thereon. Such rigidifying members 349A’ may extend between the components of the actuator unit 330’, for example. The rigidifying members 349A’ may project upward from the protective plate 349’. Such members may provide increased rigidity in bending to the protective plate 349’, if present.
Claims
CLAIMS1. A dolly fortransporting a load on a ground surface, the dolly comprising:a frame;a plurality of traction modules, each traction module of the plurality of traction modules pivotally mounted to the frame via a pivot arrangement defining a pivot axis and including:a subframe mounted to the frame via the pivot arrangement,a plurality of rollers mounted to the subframe for pivoting therewith,an actuator unit for driving the plurality of rollers, the actuator unit mounted to the subframe for pivoting therewith, the actuator unit located between the pivot axis and at least another traction module of the plurality of traction modules; andan on-board controller unit operable to operate the actuator unit.
2. The dolly of claim 1, wherein each traction module includes a drivetrain operatively coupling the actuator unit to the plurality of rollers, the drivetrain configured to transmit a torque of the actuator unit to the plurality of rollers.
3. The dolly of any one of claims 1 and 2, wherein the pivot axis intersects with at least one roller of the plurality of rollers.
4. The dolly of any one of claims 1 to 3, wherein the drivetrain is mounted to the subframe for pivoting therewith about the pivot axis.
5. The dolly of any one of claims 2 to 4, wherein the actuator unit includes a single motor drivingly engaged to the drivetrain, the drivetrain includes a reductor, the reductor and the single motor mounted in parallel with respect to each other.
6. The dolly of any one of claims 5 and 6, wherein the reductor has a reductor output having a reductor output axis, the single has a motor output having a motor output axis, the motor output axis and the reductor output axis parallel to one another.
7. The dolly of claim 6, wherein the motor output axis is parallel with respect to rolling axes of the plurality of rollers.
8. The dolly of any one of claims 5 to 7, wherein the traction module includes a brake drivingly engaged to the single motor and to the reductor.
9. The dolly of any one of claims 5 to 8, wherein the drivetrain includes a transmission unit that drivingly interconnects the single motor and the reductor.
10. The dolly of claim 9 depending on claim 8, wherein the brake, the single motor and the reductor are mounted in parallel relative to each other along the transmission unit.
11. The dolly of claim 10, wherein the brake, the single motor and the reductor are aligned on a same side of the transmission unit.
12. The dolly of any one of claims 9 to 11 , wherein the transmission unit is a gearbox type of transmission.
13. The dolly of any one of claims 2 to 4, wherein the actuator unit includes a plurality of motors, the plurality of motors operatively coupled to the drivetrain to provide in unison the torque to the plurality of rollers.
14. The dolly of claim 13, wherein the plurality of motors each have a motor output, the drivetrain includes a respective reductor at each motor output of the plurality of motors.
15. The dolly of claim 14, wherein the respective reductors at each motor output of the plurality of motors are located between the plurality of motors and the pivot axis.
16. The dolly of any one of claims 13 and 14, wherein the motor outputs of the plurality of motors extend along a respective motor output axis, the reductors each have a reductor output extending along a respective reductor output axis, the reductor output axes axially aligned with a respective one of the motor output axes.
17. The dolly of any one of claims 13 and 14, wherein the motor outputs of the plurality of motors have a respective motor output axis, the motor output axes aligned with a rolling axis of a respective one of the plurality of rollers.
18. The dolly of claim 17 wherein the reductors at each motor output of the plurality of motors have a reductor output extending along a respective reductor output axis the reductor output axes aligned with a respective one of the motor output axes.
19. The dolly of claim 17, wherein the reductors at each motor output of the plurality of motors have a reductor output extending along a respective reductor output axis, the reductor output axes aligned with a respective one of the rolling axes.
20. The dolly of any one of claims 13 to 19, wherein the plurality of motors, the drivetrain and the plurality of rollers are mounted serially in a direction transverse to the pivot axis.
21. The dolly of any one of claims 13 to 20, wherein the traction module includes a respective brake operatively coupled to each motor of the plurality of motors, the brakes operable in unison to block a rotation of the plurality of rollers.
22. The dolly of claim 21 depending on claim 20, wherein each brake is operatively coupled to a motor of the plurality of motors between the motor output and a respective one of the reductors.
23. The dolly of any one of claims 1 to 22, wherein the traction module further includes a plurality of shafts each supporting at least one roller of the plurality of rollers.
24. The dolly of claim 23, wherein the plurality of shafts are rotatably supported at opposite ends by the subframe.
25. The dolly of any one of claims 23 and 24, wherein the plurality of shafts each have a shaft axis, the shaft axes extending transversely with respect to the pivot axis.
26. The dolly of any one of claims 2 to 25, wherein the drivetrain includes a first main gear and a second main gear drivingly coupled to each other via an intermediary gear, the first gear and the second gear mounted for rotation about a respective gear axis aligned with a respective rolling axis of the plurality of rollers.
27. The dolly of any one of claims 1 to 26, wherein the pivot arrangement includes a pivot axle, the pivot axle engaging respective portions of the frame and the subframe.
28. The dolly of claim 27, wherein the pivot axle is a first pivot axle, the pivot arrangement including a second pivot axle engaging other respective portions of the frame and the subframe, the first pivot axle and the second pivot axle extending coaxially along the pivot axis and supporting one traction module of the pair of traction modules on the frame, the first pivot axle and the second pivot axle located on opposite sides on the subframe.
29. The dolly of any one of claims 1 to 28, wherein the frame defines a first abutment and a second abutment to restrict a pivoting angle of the subframe with respect to the frame, the subframe pivotable about the pivot axis between a first abutting position and a second abutting position, a portion of the subframe configured to abut against the first abutment in the first abutting position and against the second abutment in the second abutting position.
30. The dolly of claim 29, wherein first abutment and the second abutment defined in a recess in the frame, the recess configured to receive the portion of the subframe between the first abutment and the second abutment.
31. The dolly of any one of claims 29 and 30, wherein the portion of the subframe includes a first surface and a second surface, the first surface and the second surface facing towards the first abutment and the second abutment, respectively.
32. The dolly of claim 31 when depending on claim 30, wherein a pivoting angle of the subframe with respect to the frame about the pivot axis is restricted by engagement of the portion of the subframe with the first abutment, in the first abutting position, and the second abutment, in the second abutting position, the pivoting angle from a median position between the first abutting position and the second abutting position, to at least one of the first abutting position and the second abutting position is between 1 degree and 5 degrees.
33. The dolly of any one of claims 31 and 32, wherein the first surface and the second surface define a tapered end of the portion of the subframe in a direction transverse to the pivot axis.
34. The dolly of any claim 13, wherein the plurality of motors is a pair of motors.
35. A dolly for transporting a load on a ground surface, the dolly comprising:a frame;a platform extending above the frame;a plurality of traction modules configured for engagement with the ground surface, each traction module of the plurality of traction modules having a subframe pivotally mounted to the frame via a pivot arrangement defining a pivot axis; anda first abutment and a second abutment to restrict a pivoting angle of the subframe, the first abutment and the second abutment integral with the frame, the first abutment and the second abutment defined in a recess in the frame, the recess configured to receive a portion of the subframe, the portion of the subframe configured to engage the first abutment and the second abutment in a first abutting position and a second abutting position, respectively.
36. The dolly of claim 35, wherein the pivoting angle is angularly limited by engagement of the portion of the subframe with the first abutment, in the first abutting position, and the second abutment, in the second abutting position, the pivoting angle limited to between ± 1 degrees and ± 5 degrees.
37. The dolly of any one of claims 35 and 36, wherein each traction module includes a plurality of rollers and an actuator unit for driving the plurality of rollers, the plurality of rollers and the actuator unit mounted to the subframe for pivoting therewith about the pivot axis.
38. The dolly of claim 37, wherein the actuator unit is located between the pivot axis of respective ones of the traction modules.