Patent Application
20240010073
The invention relates to the field of electrical feeding of vehicles, and in particular electrical feeding of underground vehicles.
Concerns about the environmental impact of combustion of fossil fuels have led to an increased interest in electric vehicles, which have several potential benefits compared to vehicles with conventional internal combustion engines, including: a significant reduction of air pollution, as they do not emit harmful tailpipe emissions, reduced greenhouse gas emissions (depending on the fuel and technology used for electricity generation and/or charging the batteries) and reduced dependency on fossil fuels with increasingly variable supply and fluctuating prices. In underground applications such as mines, air pollution is particularly problematic.
One disadvantage to be overcome is the limited range of existing electric vehicles due to limitations in battery capacity. This is a particularly significant disadvantage for heavy vehicles such as long haulage trucks as well as construction and mining vehicles.
WO 2016/174030 discloses a system for electrical feeding of a vehicle in an underground environment such as a mine. The electrical feeding is used to propel the vehicle directly and/or to charge an onboard battery. The system comprises at least one elongated slotted element having at least one slot or groove in which electric conductors are arranged. The slotted element is suspended for example from the ceiling in the mine tunnels, and a current collector connects the vehicle electrically to the slotted element.
Such a system is advantageous since it not only provides low emissions, reduced need for battery capacity, but also good safety properties due to the slotted electric conductors. One problem however with such slotted electric conductors is that the current collector must be precisely aligned with the slots to provide adequate electric contact.
An object of the invention is to solve or improve on at least some of the problems mentioned above in the background section.
These and other objects are achieved by the present invention by means of a system and method according to the independent claims.
According to a first aspect of the invention, a system for electrically feeding at least one electrically powered vehicle is provided. The system comprises at least one elongated slotted element and at least one current collector. The at least one elongated slotted element is suspended and extends along a road section on which the at least one vehicle is adapted to travel with its lengthwise direction substantially in parallel with the direction of travel, said elongated slotted element comprising at least one electric conductor arranged in at least one slot in said elongated slotted element and being adapted to be electrically energized. The at least one current collector is adapted to co-act with said at least one suspended elongated slotted element. At least one of the current collector(s) comprises at least one contact element and at least one collector arm, and may furthermore comprise, or be provided with or be arranged to co-act with, at least one actuator. The at least one contact element is adapted to connect electrically with a corresponding at least one electric conductor of said elongated slotted element. The collector arm supports the at least one contact element at its first end and is adapted to connect directly or indirectly to an electrically propellable vehicle at its second end. The at least one actuator is configured to act on the collector arm to displace the first end thereof towards the at least one suspended elongated slotted element. The contact element is connected to the collector arm by means of a tracking device, said tracking device comprising a body part to which said at least one contact element is connected. The tracking device further comprises lateral guiding means configured to co-act with at least one laterally facing portion of the elongated slotted element to guide the tracking device laterally relative elongated slotted element. At least one lateral guiding means is laterally displaceable relative said body part by means of an alignment actuator.
As described above, a system for electrically feeding one or more electrically powered vehicles is provided, which vehicles may be a ground vehicles, road vehicles, mining vehicles or conveyances. The system comprises one or more slotted elements being elongated, which in this context means having a greater length than width and height. The system preferably comprises a plurality of such elements arranged consecutively along the extension of the road. It is understood that the elongated slotted element being suspended refers to that it is arranged above the road surface, for instance by being suspended from for example a ceiling or wall of a mining tunnel or from one or more stands, posts or the like. The elongated slotted element comprises at least one slot or groove extending along the lengthwise direction of the elongated slotted element with at least one electric conductor arranged in at least one of the slots or grooves. The elongated slotted element does not necessarily need to be suspended vertically, i.e. with its slots facing vertically downwards. On the contrary, the elongated slotted element may even be suspended horizontally, i.e. with its slots facing sideways, or at any angle between a horizontal and vertical position. It is understood that any reference herein to the lengthwise/longitudinal direction and lateral direction is defined with respect to the slotted element.
At least one of the current collector(s) comprises at least one contact element, at least one collector arm and at least one actuator. The at least one contact element may be formed from one, two, or a plurality of elements being at least partly formed of a conductive material, for instance having at least one contact surface being adapted to connect electrically and mechanically with a corresponding electric conductor. The at least one collector arm of the at least one of the current collector(s) may be formed from one or more arm segments/portions arranged in parallel or in series. The at least one actuator may comprise one or more actuators being part of the at least one of the current collector(s) or being separate part(s) co-acting with one, two or more current collectors. The at least one actuator is configured to act on the collector arm in the sense that it provides a force onto the collector arm, or onto one or more of the arm segments/portions (if any), to displace the contact element towards the at least one suspended elongated slotted element, or more specifically towards the corresponding electric conductor(s). The at least one contact element is connected to the collector arm by means of a tracking device, i.e. the tracking device is connected to the first end of the collector arm. The at least one contact element is connected to the body part rigidly or resiliently, for instance by being connected via one or more spring elements. The lateral guiding means of the tracking device is/are configured to co-act with at least one laterally facing portion of the elongated slotted element. Preferably, but not necessarily, the lateral guiding means co-act with laterally facing portions on both/opposite lateral sides of the slotted element, which sides may be facing in opposite lateral directions. The lateral guiding means may for example be formed as one or more guiding wheels configured to roll against said laterally facing portions, or as sliding elements configured to slide against the laterally facing portions. At least one of the lateral guiding means is laterally displaceable relative said body part by means of an alignment actuator, which may for example be a hydraulic actuator, a pneumatic actuator, an electric motor or a solenoid. The alignment actuator may alternatively be a mechanical actuator comprising for example a linkage and/or a hydraulic circuit.
The invention is based on the insight that the contact elements of the current collector may be precisely aligned with the corresponding conductors by having a tracking device with lateral guiding means which not only guide the contact elements, but are also laterally displaceable to be able to align the contact elements with the conductors. Such alignment is achieved by means of actuating the guiding means to provide relative lateral displacement between the contact elements and the slotted element.
In embodiments, the tracking device further comprises vertical guiding means configured to co-act with the elongated slotted element to guide the tracking device vertically relative said elongated slotted element. At least one of the vertical guiding means may be vertically displaceable relative the body part to vertically align the contact element(s) with the conductor(s) by means of the alignment actuator or an additional alignment actuator. It is understood that the vertical direction is defined with respect to the slotted element as the plane in which the slot(s) are aligned. The vertical plane is thus not necessarily perpendicular with the road surface.
In embodiments, the lateral guiding means comprises at least two guiding elements or wheels adapted to co-act with opposite lateral sides of the slotted element, the at least two guiding elements or wheels being laterally displaceable relative the body part by means of the alignment actuator between extended positions where the guiding wheels are spaced apart a first distance being greater than the lateral width of the elongated slotted element and withdrawn positions where the guiding wheels are spaced apart a second distance corresponding to said lateral width.
In embodiments, the alignment actuator of the tracking device is a mechanical actuator comprising an alignment bar having a length in the lateral direction being equal to or greater than said first distance, said alignment bar being displaceable vertically relative the body part, and being mechanically connected to the guiding elements or wheels such as to displace the at least two guiding elements or wheels towards each other when the alignment bar is pushed towards the body part. The mechanical connection may for example be achieved by means of a desmodromic type of cam arrangement which is arranged to push and pull the guiding elements or wheels laterally, a set of interconnected hydraulic cylinders, a rack and pinion arrangement, or any other suitable mechanical connection known to the person skilled in the art.
In such embodiments comprising an alignment bar, the system further comprises an electronic control system and at least one thereto connected position sensor, said electronic control system being configured to, in response to signals from said at least one position sensor, control the at least one actuator such that the alignment bar of the tracking device is laterally aligned with said elongated slotted element, whereafter the electronic control system controls the at least one actuator to displace the tracking device towards the elongated slotted element such that the alignment bar is pushed towards the body part of the tracking device, whereby the guiding wheels are actuated laterally towards the slotted element until the contact element(s) is/are laterally aligned and in contact with the corresponding electric conductor(s).
In an alternative embodiment (without the above described alignment bar), the alignment actuator of the tracking device may be an electrical, hydraulic or pneumatic actuator. In such embodiments, the system may further comprise an electronic control system and at least one thereto connected position sensor, said electronic control system being configured to control the alignment actuator such that the guiding elements or wheels are displaced to their extended positions, whereafter the electronic control system, in response to signals from said at least one position sensor, controls the at least one actuator such that tracking device is aligned with the slotted element between the guiding elements or wheels, whereafter the alignment actuator is controlled to displace the guiding elements or wheels laterally inwards towards the slotted element until the contact element(s) is/are laterally aligned with the corresponding electric conductor(s), whereafter the at least one actuator is controlled to displace the tracking device towards the slotted element until the contact element(s) is/are in contact with the corresponding electric conductor(s).
In embodiments, the elongated slotted element is provided with a flange or groove on at least one lateral side thereof or on both lateral sides, said flange(s) or groove(s) extending along the lengthwise direction of the elongated slotted element and being configured to receive the lateral guiding means or guiding wheels thereon/therein to support the tracking device vertically when the guiding elements or wheels are in abutment with the elongated slotted element.
In alternative embodiments, the laterally facing portions of the slotted element are provided with aligning edges at the bottom thereof, i.e. each laterally facing portion is provided with an aligning edge at its bottom. Edge in this context refers to the longitudinal edge which separates the laterally facing portion from the portion of the slotted element facing the vehicle, i.e. the portion/surface in which the slots are formed. It is understood that the terms top and bottom do not necessarily require the slotted element to be suspended vertically; the bottom edges are to be interpreted as the edges being closest to the slots, and the top edges are furthest away from the slots. Furthermore, the tracking device is provided with at least one set of aligning wheels or sliding elements on each lateral side thereof. Two or more sets of aligning wheels or sliding elements may be provided on each lateral side of the tracking device, the sets of aligning wheels or sliding elements being spaced apart in the lengthwise direction. The aligning wheels or sliding elements at each lateral side are disposed to form a respective aligning surface being arranged to slide laterally (and upwards/downwards assuming a vertical alignment) against the corresponding aligning edges. Put differently, each aligning wheel or sliding element is aligned to slidingly co-act with the corresponding aligning edge at the bottom of the laterally facing portion of the corresponding lateral side of the slotted element.
Furthermore, the aligning wheels or sliding elements are spaced apart a distance such that at least one aligning wheel or sliding elements of each set of aligning wheels is able to roll or slide against a corresponding aligning edge at the bottom of the laterally facing portions. In other words, at least one of the aligning wheels or sliding elements at a first/second lateral side of the slotted element is configured to roll or slide against the aligning edge at the bottom of the slotted element at the first/second lateral side thereof when the current collector is laterally aligned with the slotted element. The two sets of aligning wheels or sliding elements may be described as being laterally spaced apart a distance corresponding to the distance between aligning edges at the bottom of the slotted element. The guiding wheels or sliding elements are laterally displaceable between extended positions where the guiding wheels or sliding elements are spaced apart a first distance being greater than or equal to the lateral width of the elongated slotted element and withdrawn positions where the guiding wheels or sliding elements are disposed at a distance from each other such that the guiding wheels roll or slide against respective lateral portions. This alternative embodiment is advantageous since the corresponding alignment of the aligning edges and the aligning surface formed by the aligning wheels or sliding elements allows the current collector to automatically align with the slotted element by means of, after an initial lateral alignment which does not need to be very accurate, pushing the current collector upwards towards the slotted element such that the aligning wheel(s) or sliding element(s) slide(s) laterally on the aligning edge(s) until the current collector is centered/aligned with the slotted element. Further, the guiding wheels or sliding elements being configured to roll or slide on the laterally facing portions provides guiding of the tracking device relative said elongated slotted element.
In embodiments, the aligning edges are chamfered, and the aligning wheels are rotatable around axes of rotation disposed at corresponding angles as the aligning edges. Thus, the aligning edges and the corresponding aligning surfaces are disposed at corresponding angles. In other embodiments, the aligning edges may be rounded/convex.
In embodiments, at least one, or each, laterally facing portion of the slotted element is furthermore provided with a guiding edge at the top thereof, wherein the guiding wheels or sliding elements are laterally displaceable relative the body part by means of being supported by holding elements at the lateral sides of the tracking device, which holding elements are rotatable relative the body part around respective axes of rotation being substantially parallel with the lengthwise direction. Thus, the at least one alignment actuator is configured to rotate the holding elements to laterally displace the guiding wheels or sliding elements. At least one, or each, set of guiding wheels or sliding elements is, in the withdrawn position, disposed to co-act with the corresponding guiding edge(s) at the top of the laterally facing portion, and the guiding wheels in the withdrawn position are disposed at a distance from each other such that said at least one set of guiding wheels roll on said guiding edge. Put differently, when in the withdrawn positions, the guiding wheels are spaced apart a second distance which corresponds to (but is not exactly equal to) the lateral width of the slotted element. These embodiments are advantageous since the guiding wheels rolling on the guiding edges provides vertical guiding of the current collector.
In embodiments, the guiding edges are chamfered, and the guiding wheels are rotatable around axes of rotation disposed at corresponding angles as the guiding edges. In other embodiments, the guiding edges may be rounded/convex.
In embodiments, the guiding wheels or sliding elements at each lateral side form a respective guiding surface, wherein the aligning wheels or sliding elements and the guiding wheels or sliding elements are aligned such that, in the extended positions of the guiding wheels or sliding elements, at each lateral side, the aligning surface of the aligning wheels or sliding elements and the guiding surface of the adjacent guiding wheels or sliding elements are disposed in a common plane. For example, the aligning wheels and the guiding wheels may have the same diameter, and in the extended positions of the guiding wheels, the axis of rotation of at least one, or each, set of guiding wheels and the axis of rotation of the adjacent set of aligning wheels are located in a common plane, which plane is disposed at the same angle as the corresponding chamfered edge. These embodiments are advantageous since the aligning wheels and guiding wheels are aligned when in the extended position, which means that the guiding wheels also act as aligning wheels which means that initial lateral alignment of the current collector can be less precise.
In embodiments, the contact element(s) is/are connected to the body part by means of a displacement device configured to displace the contact elements relative the body part in a direction towards and away from the body part, e.g. towards the slotted element. Assuming that the slotted element is arranged with the slots facing downwards, the displacement device is configured to displace the contact elements vertically. The displacement device comprises an actuator, which may for example be a hydraulic actuator, a pneumatic actuator, an electric motor, a solenoid or other means of actuation that can be applied by those skilled in the art. For simplicity of description, this embodiment has been described as a vertical overhead application. It is appreciated that the orientation may be vertical, horizontal or in fact any angle to the vertical plane. In alternate versions of this embodiment the aligning wheels as described may also be sliders, skid plates, magnetic strips or other translation devices that may be applied by those skilled in the art.
In embodiments, the at least one contact element is connected to the tracking device by means of one or more resilient connection means. The resilient connection means may comprise a spring device, for instance in the form of an arm segment being at least partly formed from a resilient material.
In embodiments, the collector arm comprises a telescopic arm segment being directly or indirectly connectable to a vehicle. In such embodiments, the at least one actuator comprises an actuator configured to extend and withdraw the telescopic arm segment, which actuator may be a hydraulic actuator, an electric actuator or a pneumatic actuator.
In embodiments, the current collector comprises rotational connection means for directly or indirectly pivotably connecting the second end of the collector arm to a vehicle. The rotational connection means may comprise at least one rotational/hinge joint, i.e. providing rotation/movement relative the vehicle in one or more planes, for instance in a vertical plane. Alternatively, rotational connection means may comprise a ball joint, i.e. providing rotation and translatory movement in all directions. In such embodiments, the at least one actuator comprises one or more actuator(s) configured to rotate the current collector around one or more rotational axis/axes defined by the rotational connection means.
In embodiments, the system further comprises a sliding device arranged at the second end of the collector arm, said sliding device being configured to allow lateral movement of the collector arm relative the vehicle.
In embodiments, at least one of the collector arm(s) is formed by at least two serially arranged arm segments comprising first and second arm segments, further comprising a sliding device arranged between said first and second arm segments, said sliding device being configured to allow lateral movement of the first arm segment relative the second arm segment.
In embodiments, the system comprises at least one electrically powered vehicle to which the second end of at least one current collector is connected.
According to a second aspect of the invention, a method for aligning a current collector with a suspended elongated slotted element in a system according to the first aspect of the invention. The method comprises:
According to a third aspect of the invention, a system for electrically feeding at least one electrically powered vehicle is provided. The system according to the third aspect corresponds to the system according to the first aspect, but with the difference being that the elongated slotted element is replaced with an elongated element having at least one electric conductor mounted thereto (but not necessarily in at least one slot), or one or more elongated elements being conductive themselves and being adapted to be electrically energized.
The features of the embodiments described above are combinable in any practically realizable way to form embodiments having combinations of these features. Further, all features and advantages of embodiments described above with reference to the first aspect of the invention may be applied in corresponding embodiments of the second and third aspects of the invention.
Above discussed and other aspects of the present invention will now be described in more detail using the appended drawings, which show presently preferred embodiments of the invention, wherein:
The tracking device 510 comprises two sets of aligning wheels 514a, 514b on each lateral side thereof (only one set on each side can be seen in
The tracking device 510 further comprises two sets of guiding wheels 515a, 515b on each lateral side of the body part 511 (only one set on each side can be seen in
The aligning wheels 514a, 514b and the guiding wheels 515a, 515b have the same diameter, and in the extended positions of the guiding wheels as shown in
The current collector comprises two sets of contact elements 506, each set of contact element being adapted to co-act with a corresponding electric conductor 505 in the slotted element 502. The contact elements are connected to the body part 511 by means of a displacement device 518 which is shown in more detail in
The current collector in
In
The control system receives signals from position sensors 519a, 519b indicating that the current collector is laterally and vertically aligned, whereafter the control system orders the alignment actuators 517c, 517d to pivot the holding elements 517a, 517b until the guiding wheels 515a, 515b make contact with the respective chamfered guiding edges in the position shown in
In
For safety reasons the ground contact element makes contact before the main contact elements. This is achieved by all of the individual plate-shaped elements of contact elements 506 and ground contact elements 506′ being pre loaded with one or more springs (518a for example) that is allowed to compress. This compression spring also allows for un-even wear of individual contact elements, which may also be referred to as “brushes”, allowing all contact elements to be seated against the respective electric conductor. Actuator 518a applies a controlled force to ensure the correct contact force is maintained to the brush carrier assembly, the individual brush springs then allow each brush to maintain an even individual force to the electric conductors.
Although reference is made above to a control system, which may be an electronic control system, it is not illustrated in the figures since such systems are well known in the art.
The description above and the appended drawings are to be considered as non-limiting examples of the invention. The person skilled in the art realizes that several changes and modifications may be made within the scope of the invention. For example, tracking devices of one embodiment may be combined with collector arms from other embodiments. Further, the edges of the slotted element in
This application is a national phase application of PCT Application No. PCT/EP2021/080811, internationally filed on Nov. 5, 2021, which is a continuation-in-part of PCT Application No. PCT/EP2020/081199, internationally filed on Nov. 5, 2020, which are herein incorporated by reference in their entireties for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/080811 | 11/5/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2020/081199 | Nov 2020 | US |
| Child | 18035688 | US |
