Shuttle for a linear motor conveyor system

Abstract

A shuttle and a method of manufacturing a shuttle for a linear motor conveyor system are disclosed. In one aspect, the shuttle comprises a shuttle body, a primary guiding mechanism coupled to the shuttle body toward a first end portion thereof, a rotational compliance feature coupled toward a second end portion of the shuttle body and providing a single degree of movement freedom in yaw rotation, and a secondary guiding mechanism coupled to the rotational compliance feature. The secondary guiding mechanism, which is coupled to the rotational compliance feature, can thus be moved in yaw rotation to ensure that all wheels of the shuttle remain in contact with the rail of the linear motor conveyor system and that all supporting forces are balanced. In another aspect, the shuttle body provides rotational compliance. A linear motor conveyor system comprising one or more shuttles operating thereon is also disclosed.

Description

SHUTTLE FOR A LINEAR MOTOR CONVEYOR SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application No. 63 / 570,199, filed on March 26, 2024, the entire contents of which is incorporated herein by reference for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates to linear motor conveyor systems, and in particular to a shuttle for a linear motor conveyor system.BACKGROUND

[0003] A linear motor conveyor system is one in which a shuttle is controlled to move along a track, typically via bearings or wheels that are provided on the shuttle and rails or the like on the track which the bearings or wheels of the shuttle travel. The shuttle may be held on the track by a passive magnetic force, and be moved by electromotive force. For example, the shuttle may include a magnet and the track may include an electromagnetic field generator comprising electric coils and a motor core. The attraction between the shuttle magnet and the motor core holds the shuttle on the track. Further, the shuttle is placed on the track such that the magnet is acted on by an electromagnetic field generated by the electromagnetic field generator in order to generate an electromotive force and move the shuttle along the track.

[0004] Manufacturing tolerances in linear motor conveyor systems can lead to misalignment of the shuttle wheels and / or the rails along which the wheels travel. Such misalignment can result in a wheel of the shuttle losing contact with the rail at certain locations of the track, resulting in shuttle instability as well as increased wear and degradation of the wheels. While a large magnetic attraction between the shuttle magnet and the motor core may be sufficient to overcome some misalignment, this is not always achievable, particularly if the magnetic attraction decreases due to changes in shuttle and / or track design. For example, when wheel spacing is reduced to achieve a smaller pitch between shuttles (i.e. a minimum spacing between shuttles operating on the track), the decreased wheel spacing would make shuttle stability via large magnetic attraction unachievable.

[0005] Further, the shuttles can experience various external forces from other shuttles, process tooling, locating stops at stations, payloads, etc. The shuttles may be configured to carry a payload such that the payload can be moved from one position on the linear motor conveyor system to another. Manufacturing tolerances in the linear motor conveyor system and wheel instability can also undesirably cause the shuttle and any associated payload to deflect at certain locations of the track, which degrades accuracy and performance of the linear motor conveyor system.

[0006] Accordingly, an additional, alternative, and / or improved shuttle for a linear motor conveyor system remains highly desirable.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Further features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

[0008] FIG. 1 shows a representation of a linear motor conveyor system comprising a plurality of shuttles operating thereon;

[0009] FIG. 2A shows a side view of an example straight modular track section;

[0010] FIG. 2B shows a side view of the example straight modular track section with a shuttle thereon;

[0011] FIGs. 3A-D show a representation of a shuttle for a linear motor conveyor system in accordance with some embodiments of the present disclosure;

[0012] FIG. 4 shows an exploded view of the secondary guiding mechanism and rotational compliance feature from the shuttle;

[0013] FIG. 5A shows a detailed view of the secondary guiding mechanism and rotational compliance feature;

[0014] FIG. 5B shows a partial cross-sectional view of the secondary guiding mechanism and rotational compliance feature coupled to the shuttle body;

[0015] FIG. 6 shows a representation of rotation of the secondary guiding mechanism and rotational compliance feature;

[0016] FIG. 7 shows a representation of an alternative shuttle for a linear motor conveyor system in accordance with some embodiments of the present disclosure; and

[0017] FIG. 8 shows a method of manufacturing a shuttle for a linear motor conveyor system.

[0018] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.DETAILED DESCRIPTION

[0019] In accordance with one aspect of the present disclosure, a shuttle for a linear motor conveyor system is disclosed, comprising: a shuttle body for moving on a rail of the linear motor conveyor system along a first axis; a primary guiding mechanism coupled toward a first end portion of the shuttle body, the primary guiding mechanism comprising a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system; a rotational compliance feature coupled toward a second end portion of the shuttle body at first and second ends of the rotational compliance feature, the rotational compliance feature providing a single degree of movement freedom in yaw rotation; and a secondary guiding mechanism coupled to the rotational compliance feature, the secondary guiding mechanism comprising a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system.

[0020] In some aspects, the rotational compliance feature comprises a torsion bar having a first end portion clamped to the shuttle body and a second end portion rotatably coupled to the shuttle body.

[0021] In some aspects, the secondary guiding mechanism is coupled to the torsion bar via a wheel yoke, the wheel yoke supporting the second wheel assembly thereon.

[0022] In some aspects, the shuttle further comprises a calibrating feature that fastens the wheel yoke against the torsion bar.

[0023] In some aspects, the calibrating feature comprises a shaft clamp or a set screw.

[0024] In some aspects, the first wheel assembly and the second wheel assembly are aligned in a plane when the torsion bar is in a neutral position.

[0025] In some aspects, the first end portion of the torsion bar is clamped to the shuttle body via a shaft clamp.

[0026] In some aspects, the second end portion of the torsion bar is retained within a recess in the shuttle body.

[0027] In accordance with another aspect of the present disclosure, a shuttle for a linear motor conveyor system is disclosed, comprising: a shuttle body for moving on a rail of the linear motor conveyor system along a first axis; a primary guiding mechanism coupled toward a first end portion of the shuttle body, the primary guiding mechanism comprising a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system; and a secondary guiding mechanism coupled toward a second end portion of the shuttle body, the secondary guiding mechanism comprising a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system, wherein the shuttle body provides a single degree of movement freedom in yaw rotation for at least one of the primary guiding mechanism and the secondary guiding mechanism.

[0028] In some aspects, the two or more wheels of the first and second wheel assemblies comprise one or more of: v-groove wheels, round wheels, and flat wheels.

[0029] In some aspects, the two or more wheels of at least one of the first wheel assembly and the second wheel assembly are offset along a longitudinal axis of the shuttle body.

[0030] In some aspects, the shuttle body comprises an anti-tip feature for engaging above and / or below the rail.

[0031] In some aspects, a bumper is positioned on a side of the shuttle body.

[0032] In some aspects, the shuttle body further comprises an anti-static brush towards a middle portion of the shuttle body and configured to touch a horizontal surface of the linear motor conveyor system.

[0033] In some aspects, the shuttle body further comprises a lubricating felt configured for lubricating the rail of the linear motor conveyor system along which the shuttle is configured to operate along.

[0034] In some aspects, the shuttle body is configurable for mounting a payload to the shuttle body.

[0035] In some aspects, the shuttle further comprises a permanent magnet array positioned within the shuttle body between the primary guiding mechanism and the secondary guiding mechanism

[0036] In accordance with another aspect of the present disclosure, a linear motor conveyor system is disclosed, comprising: one or more shuttles according to any one of the above aspects; and a track supporting the one or more shuttles thereon, the track comprising: at least one rail for guiding movement of the one or more shuttles; and an interior volume for housing a plurality of electrical coils of a linear motor providing a controllable motive force to the one or more shuttles.

[0037] In some aspects, the track comprises a plurality of modular track sections.

[0038] In accordance with another aspect of the present disclosure, a method of manufacturing a shuttle for a linear motor conveyor system is disclosed, the method comprising: mounting a primary guiding mechanism toward a first end portion of a shuttle body, the primary guiding mechanism comprising a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along a rail of the linear motor conveyor system; coupling a secondary guiding mechanism to arotational compliance feature, the secondary guiding mechanism comprising a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system; and coupling the rotational compliance feature toward a second end portion of the shuttle body at first and second ends of the rotational compliance feature, the rotational compliance feature providing a single degree of movement freedom in yaw rotation.

[0039] In some aspects, the method further comprises: mounting the primary guiding mechanism and the secondary guiding mechanism onto a fixture; and configuring the rotational compliance feature to align the first wheel assembly and the second wheel assembly in a plane when the rotational compliance feature is in a neutral position.

[0040] In some aspects, the rotational compliance feature is a torsion bar, and the secondary guiding mechanism is coupled to the torsion bar via a wheel yoke, the wheel yoke supporting the second wheel assembly thereon, the method further comprising fastening the wheel yoke to the torsion bar.

[0041] In some aspects, the method further comprises attaching a permanent magnet array to the shuttle body between the primary guiding mechanism and the secondary guiding mechanism.

[0042] A shuttle for a linear motor conveyor system and a method of manufacturing a shuttle for a linear motor conveyor system are disclosed. The shuttle in accordance with the present disclosure is designed to realize a controllable torsional softness in one direction and a strong bending stiffness in all other directions of the shuttle. In one aspect, the shuttle comprises a shuttle body, a primary guiding mechanism coupled to the shuttle body toward a first end portion thereof, a rotational compliance feature coupled toward a second end portion of the shuttle body and providing a single degree of movement freedom in yaw rotation (as defined below), and a secondary guiding mechanism coupled to the rotational compliance feature. In another aspect, instead of a separate rotational compliance feature, the shuttle body provides rotational compliance and is configured to provide a single degree of movement freedom in yaw rotation for at least one of the primary guiding mechanismand the secondary guiding mechanism. A linear motor conveyor system is also disclosed comprising one or more shuttles in accordance with the present disclosure operating thereon.

[0043] The primary guiding mechanism and the secondary guiding mechanism respectively comprise first and second wheel assemblies configured to guide the shuttle along a rail of the linear motor conveyor system. The primary guiding mechanism guides all degrees of freedom of the shuttle body with the exception of roll rotation and the travel axis direction along the track. The secondary guiding mechanism guides the shuttle further in roll rotation. Rotational compliance is achieved by providing a single degree of movement freedom in yaw rotation to ensure that all wheels of the shuttle (i.e. the wheels of the first and second wheel assemblies) remain in contact with the rail of the linear motor conveyor system and that all supporting forces are balanced. As explained in more detail herein below, the yaw rotation is about an axis of rotation that is perpendicular to both an axis of shuttle travel along the track and to an axis of the magnetic attractive force between the shuttle and the track.

[0044] In one embodiment, the shuttle comprises a rotational compliance feature that is ductile and elastic and provides compliance such that it can deform elastically when an external force is applied. The rotational compliance feature is configured to provide a single degree of movement freedom within the secondary guiding mechanism in yaw rotation. The second wheel assembly, which is coupled to the rotational compliance feature, can thus be moved in yaw rotation to ensure that all wheels of the shuttle remain in contact with the rail of the linear motor conveyor system. The rotational compliance feature may comprise a torsion bar that provides a restoring torsion in either direction of yaw rotation about a nominal / initial state of the torsion bar.

[0045] Accordingly, the rotational compliance can overcome manufacturing tolerances in the shuttles and / or rails, and can also compensate for a changing nominal state due to uneven wear of the wheels, to thus ensure the wheels of the shuttle remain in contact with the rail. Meanwhile, the rotational compliance only provides a single degree of movement freedom in yaw rotation and is rigid in all otherdirections. For a shuttle comprising a rotational compliance feature, the rigidity of the rotational compliance feature is achieved in part because both ends of the rotational compliance feature are coupled to the shuttle body, so the second wheel assembly is stable in all other directions. For a shuttle comprising a shuttle body that provides rotational compliance, the shuttle body is engineered to ensure rigidity in all other directions. The rigidity is important as the shuttle experiences various forces, sometimes in opposing directions, as the shuttle travels along the track. The rigidity also helps to ensure that the shuttle and any associated payload doesn’t deflect as the shuttle travels along the track and experiences such forces.

[0046] Embodiments are described below, by way of example only, with reference to Figures 1-8.

[0047] FIG. 1 shows a representation of a linear motor conveyor system 100 comprising a plurality of shuttles 150 operating thereon. The linear motor conveyor system 100 comprises a track supported on a support surface 101 and supports the shuttles 150 thereon. The linear motor conveyor system 100 may comprise a plurality of modular track sections. As seen in FIG. 1 , the modular track sections comprise straight track sections 110 and curved track sections 112. As described further herein below, the shuttles 150 in accordance with the present disclosure are capable of running along tightly curved track sections, and the curved track sections 112 may for example provide a less than 300mm diameter 180-degree curve. While the linear motor conveyor system 100 is shown as comprising four straight track sections 110 (two on each side) and two curved track sections 112 (one on each end), it will be appreciated that the modular nature of the track sections allow for various sizes and shapes of conveyor systems. Further, while the linear motor conveyor system 100 generally defines a circular track, it will be appreciated that different track configurations may be possible.

[0048] Each of the modular track sections comprise a rail 130 for supporting a wheeled shuttle 150 and guiding the shuttles along the track. The wheeled shuttles 150 are configured to ride, move, or otherwise travel along the rail in a first axis direction (e.g. x-axis). In a manufacturing environment, for example, the wheeled shuttles 150 may be intended to travel between workstations (not shown) and maysupport a payload that is to be operated on automatically by, for example, a robot, while moving or at a workstation, or may travel to a workstation or other work area intended for manual operations. It will be appreciated that through the operation of the linear motor conveyor system 100 and the wheeled shuttles 150 operating thereon, various operations may be performed, such as to provide for the assembly of a product.

[0049] FIG. 2A shows a side view of an example straight modular track section 110. FIG. 2B shows a side view of the example straight modular track section 110 with a shuttle 150 thereon. As described further herein, each of the shuttles 150 generally comprise two or more wheel assemblies that are offset along a second axis perpendicular to the direction of travel (e.g. the z-axis, i.e. vertically offset). Accordingly, the rail 130 may comprise a first rail section 130a for interfacing with a first wheel assembly of the wheeled shuttles, and a second rail section 130b for interfacing with a second wheel assembly of the wheeled shuttles. As seen in FIG. 2B each of the first rail section 130a and the second rail section 130b are configured to engage with respective wheels of the first and second wheel assemblies of the shuttle 150. In FIG. 2B, the first rail section 130a interfaces with a first wheel 156 of the first wheel assembly, and the second rail section 130b interfaces with a second wheel 160 of the second wheel assembly. Each of the wheel assemblies comprise one or more wheels, typically two or more wheels for engaging with the rail of the track, and the wheels of a given wheel assembly may also be vertically offset. As described further below, the first and second wheel assemblies of the shuttle 150 also comprise wheels on the opposite side of the shuttle body (not seen in FIG. 2B). It will be appreciated that FIGs. 2A and 2B show just one example of a modular track section, and that different track section configurations to support different shuttle designs may be possible. As one example, the shuttle may comprise a wheel assembly that is arranged at a top of the track section, and the first rail section 130a may accordingly be provided at a top of the track section instead of at a front of the track section.

[0050] In some embodiments, as described further herein, the wheels of the first and / or second wheel assemblies may be v-groove wheels, and the corresponding rail profile is configured to interface with v-groove wheels. Alternatively, the wheels ofthe first and / or second wheel assemblies may be flat or round, and the corresponding rail profile is configured to interface with such wheels. In general, v-groove wheels (and corresponding rail profiles) are desirable in at least one of the first and second wheel assemblies to locate the shuttle and to contain the shuttle in a vertical axis (e.g. z-axis) and in rotation about a normal axis (e.g. y-axis).

[0051] Referring back to FIG. 1 , each of the modular track sections are electrically and mechanically self-contained and connectable to and separable from one another so as to be modular in nature. The track profile or surface of each modular track section defines an interior volume that houses a plurality of electric coils and a motor core (not shown). The plurality of electric coils (not shown) is configured to produce a magnetic force for moving the wheeled shuttles 150 along the track in a first axis (the x-axis in FIG. 1). The magnetic force for moving the shuttles 150 is created by the interaction of the magnetic flux created by the plurality of coils (not shown) embedded within an interior volume of the track and magnetic elements of the wheeled shuttles 150. The electric coils may be individually excited according to a position of a wheeled shuttle 150 to generate a magnetic force acting on that respective shuttle. A passive magnetic force between a magnet(s) on the shuttle and the motor core captures / holds the wheeled shuttles 150 on the track. The magnetic attractive force between the shuttle and the track is in a second axis (the y-axis in FIG. 1). Accordingly, the magnetic force can be thought of as having a motive force component for directing movement of the wheeled shuttles 150 along a direction of travel on the track in the x-axis, and a capturing force component to laterally hold the wheeled shuttles 150 on the track and in spaced relation to the track surface in the y- axis direction. In at least some conveyor systems, the motive force and the capturing force can be provided by the same magnetic flux.

[0052] As described above, manufacturing tolerances in the shuttle and / or rails can result in locations on the track where one or more wheels of a shuttle lift off the rail. Further, the various forces experienced by the shuttle as it travels along the track can also result in one or more wheels of the shuttle lifting off the rail and / or the shuttle deflecting as it travels (e.g. rotating about the x-axis, i.e. roll, and / or rotation about the y-axis, i.e. pitch). A consequence of one or more wheels of the shuttle losing contactwith the rail is shuttle instability as well as increased wear and degradation of the wheels.

[0053] In accordance with the present disclosure, a shuttle comprises a rotational compliance feature that is coupled to at least one of the wheel assemblies and provides a single degree of movement freedom in yaw rotation (i.e. rotation about the z-axis, which is perpendicular to both an axis of shuttle travel along the track (x- axis) and to an axis of the magnetic attractive force between the shuttle and the track (y-axis)). Accordingly, a wheel assembly that is coupled to the rotational compliance feature can be moved in yaw rotation, ensuring that all wheels of the shuttle remain in contact with the rail of the linear motor conveyor system and that all supporting forces are balanced. The rotational compliance feature may be coupled to the shuttle body or provided by the shuttle body itself, and provides a prescribed rigidity in yaw rotation such that the degree of movement freedom is slight and just barely flexible enough in rotation to ensure that the wheels of the shuttle remain in contact with the rail but no more flexible than that for the sake of stability. Meanwhile, the rotational compliance feature is rigid in all other directions (i.e. x-axis, y-axis, z-axis, roll, and pitch) so that all other movement of the shuttle is guided by the wheels in contact with the rail of the track section and to ensure that the shuttle does not deflect as it travels along the track.

[0054] FIGs. 3A-D show a representation of a shuttle for a linear motor conveyor system in accordance with some embodiments of the present disclosure. FIG. 3A shows a front isometric view, FIG. 3B shows a front view, FIG. 3C shows a rear view, and FIG. 3D shows a side view of the shuttle 150.

[0055] As seen in FIGs. 3A and 3B, the shuttle 150 comprises a shuttle body 152 that structurally supports the shuttle elements. Previous shuttle designs have included closed wheel shuttle designs where the wheels are contained within the shuttle body, as well as open wheel shuttle designs where the wheels are entirely outside of the shuttle body. Disadvantages of the closed wheel shuttle design is that the shuttle does not perform well on tight or inside (e.g. concave) corners. Disadvantages of open wheel shuttle designs is that the shuttle is generally not particularly rigid for cantilevered loads and is not as structurally robust. Also, with openwheel shuttle designs there is a greater risk of payload contamination due to wheel debris. As seen in FIGs. 3A-D, the shuttle 150 falls in between open and closed wheel approaches, and the shuttle body 152 partially encloses the wheels to provide enhanced structural rigidity compared to open wheel approaches, while still being able to accommodate inside / concave corners and enable reduced shuttle-to-shuttle pitch and compact nesting compared to closed wheel approaches.

[0056] Referring to FIG. 3C, the shuttle 150 comprises a primary guiding mechanism 154 coupled toward a first end of the shuttle body 152, and a secondary guiding mechanism 158 coupled toward a second end portion of the shuttle body 152. The primary guiding mechanism 154 and the secondary guiding mechanism 158 are offset from each other along a longitudinal axis of the shuttle body (i.e. in the vertical or z-axis direction). The primary guiding mechanism 154 comprises a first wheel assembly comprising two or more wheels 156. The secondary guiding mechanism 158 comprises a second wheel assembly comprising two or more wheels 160. In this exemplary configuration shown in FIG. 3C, each of the primary guiding mechanism 154 and the secondary guiding mechanism 158 comprise a pair of wheels, and the wheels of each pair are also vertically offset along a longitudinal axis of the shuttle body.

[0057] The wheels of the first and second wheel assemblies are configured for guiding the shuttle body along the rail of the linear motor conveyor system. For example, as described with reference to FIGs. 2A and 2B, the wheels of the first and second wheel assemblies may each interface with respective rail sections. The primary guiding mechanism 154 is rigidly coupled to the shuttle body 152 and guides all degrees of freedom of the shuttle body 152 with the exception of roll rotation and the travel axis direction along the track. The secondary guiding mechanism 158 is movable in yaw rotation via a rotational compliance feature, as described below.

[0058] The wheels 156 and 160 may be various kinds of wheels, such as v- groove wheels, round wheels, flat wheels, etc. In this exemplary configuration, the wheels 156 of the first wheel assembly 154 comprises a pair of v-groove wheels, and the wheels 160 of the second wheel assembly 158 comprises a pair of flat wheels. V- groove wheels may be advantageously used for the primary guiding mechanism asthese help to locate the shuttle and to contain the shuttle in the z-axis and in rotation in pitch. The wheels in each pair of wheels are supported at respective sides of the shuttle body 152.

[0059] While FIGs. 3A-D show a particular configuration of the primary guiding mechanism 154 and the secondary guiding mechanism 158 for a shuttle 150, it will be appreciated that various modifications to the shuttle design are also possible without departing from the scope of this disclosure. For example, additional guiding mechanisms and / or wheel assemblies may be coupled to the shuttle body, and / or each wheel assembly may comprise more than two wheels, and / or the two or more wheels of a given wheel assembly may be arranged in different configurations than that shown. Additionally or alternatively, a top of the shuttle body may extend over an upper portion of the track, and the primary guiding mechanism may be arranged at such an extension of the shuttle body. Additionally or alternatively, in FIG. 3C the primary guiding mechanism is shown as being coupled toward an upper end portion of the shuttle body and the secondary guiding mechanism is shown as being coupled toward a lower end portion of the shuttle body, but this orientation may be reversed. Additionally or alternatively, more than one guiding mechanism may be coupled to the shuttle body via the rotational compliance member that is described below.

[0060] As described above, the secondary guiding mechanism is coupled to a rotational compliance feature. The rotational compliance feature provides a single degree of movement freedom in yaw rotation, and thus the secondary guiding mechanism is movable in yaw rotation. The rotational compliance feature is comprised of a material that is ductile and elastic (i.e. it does not deform plastically / permanently). The rotational compliance feature may for example be made of steel or other similar materials. FIG. 4 shows an exploded view of the secondary guiding mechanism and rotational compliance feature from the shuttle 150. Further, FIG. 5A shows a detailed view of the secondary guiding mechanism and rotational compliance feature, and FIG. 5B shows a partial cross-sectional view of the secondary guiding mechanism and rotational compliance feature coupled to the shuttle body. In FIGs. 4, 5A, and 5B, the rotational compliance feature is provided by a torsion bar 162, which has a tightly prescribed degree of movement freedom in yawrotation and is rigid in all other directions. As an example, the torsion bar 162 may be designed to provide for + / -0.25mm of movement per wheel (i.e. 0.50mm total maximum compliance to accommodate a 0.50mm error of the rails within the wheel pitch, which may for example be 50mm).

[0061] Referring concurrently to FIGs. 4, 5A, and 5B, the torsion bar 162 is coupled toward a second end portion of the shuttle body 152 at first and second ends of the torsion bar 162. In some embodiments, a first end portion of the torsion bar 162 may be clamped to the shuttle body 152 via a shaft clamp 164 and fasteners 166. One or more sleeve bearings 168 may be provided along the length of the torsion bar 162 to facilitate movement in yaw rotation. The second end portion of the torsion bar 162 may be rotatably coupled to the shuttle body 152. For example, the second end portion of the torsion bar 162 may be retained within a recess 152a of the shuttle body 152.

[0062] The secondary guiding mechanism 158 comprising the second wheel assembly shown having wheels 160 is coupled to the torsion bar 162 via a wheel yoke 170. The wheel yoke 170 is fastened against the torsion bar 162 via a split clamp and screw 172, or a set screw. The use of the split clamp and screw 172 to fasten the wheel yoke 170 against the torsion bar 162 also acts as a calibrating feature that can overcome manufacturing tolerances in the shuttle body 152 and secondary guiding mechanism 158 including wheels 160. Specifically, the screw 172 can be tightened within the split clamp to fasten the wheel yoke 170 against the torsion bar 162 while held in a perfect or nominal state, e.g. via a fixture or while mounted on a known good section of track, to ensure that the second wheel assembly having wheels 160 are properly aligned with the corresponding rail section of the track.

[0063] As described above, the torsion bar 162 provides a single degree of movement freedom in yaw rotation. The torsion bar 162 is clamped to the shuttle body 152 at a first end thereof (e.g. via the shaft clamp 164) and is rotatably coupled to the shuttle body 152 at a second end thereof (e.g. retained within recess 152a). The wheel yoke 170 supporting the second wheel assembly thereon is fastened against the torsion bar 162 along a length thereof. As the shuttle 150 travels along the track, one or more wheels of the shuttle may lift off the track due to manufacturing tolerancesin the wheels / rails, external forces acting on the shuttle, etc. If the secondary guiding mechanism 158 begins to rotate in either direction of yaw rotation, the torsion bar provides a restoring torsion in an opposite direction of yaw rotation to return the torsion bar to a nominal / initial state and thus ensure the wheels 160 of the secondary guiding mechanism remain in contact with the rail of the track section. For example, when the torsion bar is in a neutral position, the wheels of the first and second wheel assemblies may be substantially in a plane parallel to a front surface of the track. If the second wheel assembly begins to rotate outside of that plane due to misalignment and / or external forces, the torsion bar provides a restoring torsion back to the neutral position to ensure that all wheels of the shuttle remain in contact with the rail.

[0064] As also described above, it is important that the torsion bar 162 is rigid in all other directions outside of yaw rotation to ensure stability of the secondary guiding mechanism and to prevent deflection of the shuttle body as it travels along the track. In addition to the design of the torsion bar itself, the rigidity of the torsion bar 162 outside of yaw rotation is facilitated by coupling both ends of the torsion bar 162 to the shuttle body 152. For example, if only the upper end of the torsion bar 162 was coupled to the shuttle body 152, the forces experienced by the torsion bar 162 may result in the lower end of the torsion bar moving / deflecting outside of yaw rotation, and potentially causing a problem of excessive deformation of the shuttle 150. Since both the upper end and the lower end of the torsion bar 162 are coupled to the shuttle body 152, such movement can be prevented.

[0065] FIG. 6 shows a representation of rotation of the secondary guiding mechanism and rotational compliance feature. In FIG. 6, the wheels 160 of the second wheel assembly are rotating in a clockwise direction. The rotation of the wheels 160 may be caused for example by forces from the rail of the track. As represented in FIG. 6, as the wheels 160 rotate in the clockwise direction, the torsion bar 162 provides a restoring torsion to cause rotation in an opposite direction (e.g. counter-clockwise direction), and thereby re-align the wheels 160 to be in contact with the track.

[0066] It will be appreciated that while a rotational compliance feature comprising a torsion bar has been described, other implementations of a rotationalcompliance feature may be possible provided that such configurations allow a single degree of movement freedom in yaw rotation.

[0067] Referring back to FIGs. 3C and 3D a permanent magnet 174 may be positioned within the shuttle body between the first guiding mechanism 154 and the second guiding mechanism 158.

[0068] The shuttle 150 may also comprise various other enhanced features. For example, the shuttle 150 may comprise a lubricating felt 176 that is configured to lubricate a rail along which the wheels travel along. The shuttle 150 shown in FIG. 3C has a single lubricating felt 176 for lubricating a rail along which the wheels of the first wheel assembly travel along (see also FIG. 2B), but it will be apparent that an additional or alternative lubricating felt can be provided near the second wheel assembly to lubricate the lower rail. Further, the shuttle 150 may comprise an antistatic brush 178 coupled to the shuttle body 152 and provided in a protected location. In this embodiment, the anti-static brush is provided in a middle portion of the shuttle body 152 and touches on horizontal surfaces of the linear motor conveyor system, which stays on the same plane regardless of section shape and allows the anti-static brush to operate on different track section types. Further still, the shuttle body 152 may comprise anti-tip features 180 (see FIG. 3D), which engage above and below the rail in the track section that the first wheel assembly engages with (see for example FIG. 2B), and prevents the shuttle body 152 from tipping. The shuttle body 152 may also comprise a bumper 182 positioned on a side thereof to protect the shuttle 150 from contact with other shuttles or objects.

[0069] FIG. 7 shows a representation of an alternative shuttle for a linear motor conveyor system in accordance with some embodiments of the present disclosure. As described above, in accordance with another aspect of the present disclosure a shuttle for a linear motor conveyor system is disclosed wherein the shuttle body provides a single degree of movement freedom in yaw rotation for at least one of the primary guiding mechanism and the secondary guiding mechanism. FIG. 7 depicts an example of such an alternative shuttle 150’. The shuttle 150’ comprises a shuttle body 152’, a primary guiding mechanism 154’ coupled toward a first end portion of the shuttle body 152’ and comprising wheels 156’, and a secondary guiding mechanism158’ coupled toward a second end portion of the shuttle body 152’ and comprising wheels 160’. Various other enhanced features may also be provided on the shuttle 150’, such as those described above for the shuttle 150.

[0070] In this embodiment, the shuttle body 152’ is designed to provide a single degree of movement freedom in yaw rotation. In the example shuttle 150’ depicted in FIG. 7, the shuttle body 152’ is a thin shell that is soft in torsion to provide degree of movement freedom in yaw rotation, yet is sufficiently strong against bending. The shuttle body 152’ is also uniform in shape so that the twist occurs approximately evenly over the height of the body. Accordingly, in the example shuttle 150’, a degree of movement freedom in yaw rotation is provided for both the primary guiding mechanism 154’ and the secondary guiding mechanism 158’. However, it will also be appreciated that the shuttle body may be engineered differently to provide a degree of movement freedom in yaw rotation for only one of the primary guiding mechanism 154’ and the secondary guiding mechanism 158’. That is, the shuttle body 152’ may be designed such that the top half deforms uniformly and the bottom half is stiff (thus providing a degree of movement freedom in yaw rotation for the primary guiding mechanism 154’), or the shuttle body 152’ may be designed such that the top half is stiff and the bottom half deforms uniformly (thus providing a degree of movement freedom in yaw rotation for the secondary guiding mechanism 158’).

[0071] FIG. 8 shows a method 800 of manufacturing a shuttle for a linear motor conveyor system. The method 800 may be used to manufacture the shuttle 150 as described herein.

[0072] The method 800 comprises mounting a primary guiding mechanism toward a first end portion of a shuttle body (802). The primary guiding mechanism comprises a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along a rail of the linear motor conveyor system. The method 800 also comprises coupling a secondary guiding mechanism to a rotational compliance feature (804). The secondary guiding mechanism comprises a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system. In some embodiments, the rotational compliance feature is a torsion bar, and the secondary guiding mechanismis coupled to the torsion bar via a wheel yoke that supports the second wheel assembly thereon. Coupling the secondary guiding mechanism to the torsion bar may comprise fastening the wheel yoke to the torsion bar, for example by using a shaft clamp or a set screw, which acts as a calibrating feature to correct any misalignment caused by manufacturing tolerances of the shuttle body and / or second wheel assembly.

[0073] The rotational compliance feature is coupled toward a second end portion of the shuttle body at first and second ends of the rotational compliance feature (806). As has been described above, the rotational compliance feature provides a single degree of movement freedom in yaw rotation.

[0074] A permanent magnet array may be attached to the shuttle body between the primary guiding mechanism and the secondary guiding mechanism (808).

[0075] The method 800 may also further comprise mounting the primary guiding mechanism and the secondary guiding mechanism onto a fixture (810) or a section of track that is known to be good (i.e. that does not have manufacturing errors), and configuring the rotational compliance feature to align the wheels of the first wheel assembly and the second wheel assembly in a plane when the rotational compliance feature is in a neutral position (812). For example, where the rotational compliance feature comprises a torsion bar and coupling the secondary guiding mechanism to the torsion bar comprises fastening a wheel yoke to the torsion bar, the shaft clamp or set screw may be loosened / tightened such that the wheels of first and second wheel assemblies are arranged in a plane when the torsion bar is in a neutral position. It will be appreciated that alternative means may also be provided to configure the rotational compliance feature, such as by using a different fixture where the shuttle sits stationary on a bench and a handheld tool references the wheels of the first and second wheel assemblies to be in a plane, then retightening the clamp / screw.

[0076] It would be appreciated by one of ordinary skill in the art that the system and components shown in the figures may include components not shown in the drawings. For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale and are only schematic. It will be apparent to persons skilled inthe art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.

[0077] It is contemplated that any part of any aspect or embodiment discussed in this specification can be implemented or combined with any part of any other aspect or embodiment discussed in this specification.

[0078] It should be recognized that features and aspects of the various examples provided above can be combined into further examples that also fall within the scope of the present disclosure.

[0079] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0080] The invention may also broadly consist in the parts, elements, steps, examples and / or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and / or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

Claims

CLAIMS:1 . A shuttle for a linear motor conveyor system comprising: a shuttle body for moving on a rail of the linear motor conveyor system along a first axis; a primary guiding mechanism coupled toward a first end portion of the shuttle body, the primary guiding mechanism comprising a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system; a rotational compliance feature coupled toward a second end portion of the shuttle body at first and second ends of the rotational compliance feature, the rotational compliance feature providing a single degree of movement freedom in yaw rotation; and a secondary guiding mechanism coupled to the rotational compliance feature, the secondary guiding mechanism comprising a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system.

2. The shuttle of claim 1 , wherein the rotational compliance feature comprises a torsion bar having a first end portion clamped to the shuttle body and a second end portion rotatably coupled to the shuttle body.

3. The shuttle of claim 2, wherein the secondary guiding mechanism is coupled to the torsion bar via a wheel yoke, the wheel yoke supporting the second wheel assembly thereon.

4. The shuttle of claim 3, further comprising a calibrating feature that fastens the wheel yoke against the torsion bar.

5. The shuttle of claim 4, wherein the calibrating feature comprises a shaft clamp or a set screw.

6. The shuttle of any one of claims 2 to 5, wherein the first wheel assembly and the second wheel assembly are aligned in a plane when the torsion bar is in a neutral position.

7. The shuttle of any one of claims 2 to 6, wherein the first end portion of the torsion bar is clamped to the shuttle body via a shaft clamp.

8. The shuttle of any one of claims 2 to 7, wherein the second end portion of the torsion bar is retained within a recess in the shuttle body.

9. A shuttle for a linear motor conveyor system, comprising: a shuttle body for moving on a rail of the linear motor conveyor system along a first axis; a primary guiding mechanism coupled toward a first end portion of the shuttle body, the primary guiding mechanism comprising a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system; and a secondary guiding mechanism coupled toward a second end portion of the shuttle body, the secondary guiding mechanism comprising a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system, wherein the shuttle body provides a single degree of movement freedom in yaw rotation for at least one of the primary guiding mechanism and the secondary guiding mechanism.

10. The shuttle of any one of claims 1 to 9, wherein the two or more wheels of the first and second wheel assemblies comprise one or more of: v-groove wheels, round wheels, and flat wheels.11 . The shuttle of any one of claims 1 to 10, wherein the two or more wheels of at least one of the first wheel assembly and the second wheel assembly are offset along a longitudinal axis of the shuttle body.

12. The shuttle of any one of claims 1 to 11 , wherein the shuttle body comprises an anti-tip feature for engaging above and / or below the rail.

13. The shuttle of any one of claims 1 to 12, wherein a bumper is positioned on a side of the shuttle body.

14. The shuttle of any one of claims 1 to 13, wherein the shuttle body further comprises an anti-static brush towards a middle portion of the shuttle body and configured to touch a horizontal surface of the linear motor conveyor system.

15. The shuttle of any one of claims 1 to 14, wherein the shuttle body further comprises a lubricating felt configured for lubricating the rail of the linear motor conveyor system along which the shuttle is configured to operate along.

16. The shuttle of any one of claims 1 to 15, wherein the shuttle body is configurable for mounting a payload to the shuttle body.

17. The shuttle of any one of claims 1 to 16, further comprising a permanent magnet array positioned within the shuttle body between the primary guiding mechanism and the secondary guiding mechanism18. A linear motor conveyor system, comprising: one or more shuttles according to any one of claims 1 to 17; and a track supporting the one or more shuttles thereon, the track comprising: at least one rail for guiding movement of the one or more shuttles; and an interior volume for housing a plurality of electrical coils of a linear motor providing a controllable motive force to the one or more shuttles.

19. The linear motor conveyor system of claim 18, wherein the track comprises a plurality of modular track sections.

20. A method of manufacturing a shuttle for a linear motor conveyor system, the method comprising:mounting a primary guiding mechanism toward a first end portion of a shuttle body, the primary guiding mechanism comprising a first wheel assembly comprising two or more wheels configured for guiding the shuttle body along a rail of the linear motor conveyor system; coupling a secondary guiding mechanism to a rotational compliance feature, the secondary guiding mechanism comprising a second wheel assembly comprising two or more wheels configured for guiding the shuttle body along the rail of the linear motor conveyor system; and coupling the rotational compliance feature toward a second end portion of the shuttle body at first and second ends of the rotational compliance feature, the rotational compliance feature providing a single degree of movement freedom in yaw rotation.21 . The method of claim 20, further comprising: mounting the primary guiding mechanism and the secondary guiding mechanism onto a fixture; and configuring the rotational compliance feature to align the first wheel assembly and the second wheel assembly in a plane when the rotational compliance feature is in a neutral position.

22. The method of claim 20 or claim 21 , wherein the rotational compliance feature is a torsion bar, and wherein the secondary guiding mechanism is coupled to the torsion bar via a wheel yoke, the wheel yoke supporting the second wheel assembly thereon, the method further comprising fastening the wheel yoke to the torsion bar.

23. The method of any one of claims 20 to 22, further comprising attaching a permanent magnet array to the shuttle body between the primary guiding mechanism and the secondary guiding mechanism.

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