Patent Description:
Some conveyor systems utilize caster wheels to support different forms of conveyance apparatuses on the conveyor system, such as a cart or shuttle that is supported on a conveyor frame of an endless loop or circular conveyor. Proper orientation of caster wheels is critical to reduce damage and wear to the caster wheels themselves and the conveyor system equipment. Improper orientation of the caster wheels at the time of installation may lead to breakage of conveyor equipment due to jamming and pinching conflicts between the wheels and the frame of the conveyor. As an example, an endless loop conveyor in the form of a circular sorter is a machine composed of a series of transport vehicles connected to each other in a closed loop, wherein the transport vehicles travel on a track defined by the conveyor frame. These transport vehicles may include vertical support caster wheels functionality of re-orienting to allow the transport vehicle to travel along horizontal curves of the conveyor frame. The caster wheels may have an orientation possibility of two hundred and ten degrees (<NUM>°) beyond a rectilinear travelling direction. This large degree of orientation possibility permits the transport vehicle to travel along tight conveyor curves. During installation of the transport vehicles within the conveyor system, it is possible that the caster wheels may be positioned in the opposite direction to that of travel, such as if a human installation technician does not carefully inspect and ensure that the caster wheels are properly oriented as the transport vehicle is loaded on the track. A caster wheel alignment system according to the preamble of claims <NUM> and <NUM> and a conveyor system according to the preamble of claim <NUM> are known from <CIT>.

The present invention provides a caster wheel alignment system, which selectively intercepts miss-oriented or improperly aligned caster wheels of transport vehicles of a conveyor system and re-orients the wheels to a proper trailing orientation. The alignment system includes a horizontal cam for redirecting the miss-oriented caster wheels and a may include a vertical cam, which acts may raise the horizontal cam above an axle of the transport vehicle to permit the vehicle to pass through the alignment system. The system is configured such that the horizontal cam will not impede or impact properly aligned caster wheels of transport vehicles as they pass through the system. The alignment system may preferably be installed on the conveyor system during the process of installing the transport vehicles on the conveyor and is subsequently removed once the installation is complete and the orientation of all the transport vehicle caster wheels is confirmed. While the alignment system is particularly well suited for conveyor systems, it is contemplated that the alignment system may be utilized for many other situations in which caster wheel miss-orientation is common or problematic, such as for autonomous vehicles or shopping carts, for example.

According to one form of the present invention, a caster wheel alignment system is provided for a conveyor and includes a support frame having a stationary frame and a floating frame that is freely movable relative to the stationary frame, a horizontal cam, and a vertical cam. The stationary frame is removably coupled to the frame of the conveyor proximate a track upon which a transport vehicle operates. The float frame is attached to the stationary frame at a float frame guide system and the float frame is substantially freely moveable about a vertical travel path defined by the guide system. The horizontal cam is coupled to the float frame and positioned to impede a travel path of a caster wheel of a transport vehicle that travels upon the drive rail. The horizontal cam is positioned and dimensioned to automatically adjust the orientation of the caster wheel from an improper leading orientation in which the caster wheel is leading an axle of the transport vehicle to a proper trailing orientation in which the caster wheel is trailing the vehicle axle. The vertical cam is coupled to one or both of the float frame and the horizontal cam and the vertical cam, in an initial or lowered position, is positioned to be impacted by a portion of the transport vehicle, such as the axle, as it travels along the drive rail past and/or through the alignment system. The float frame is urged to raise upward, in response to an impact between the vertical cam and the transport vehicle, to raise upward such that the horizontal cam clears the axle and the caster wheel of the transport vehicle to permit the vehicle to pass through the alignment system. The alignment system may include a float guide disposed between the stationary frame and the float frame. The float guide defines the vertical path along which the float frame is movable relative to the stationary frame. In one aspect, the horizontal cam and the vertical cam are each formed of a material having a hardness that is less than the hardness of the caster wheel and the axle of the transport vehicle. Thus, wear and tear on the conveyor components may be reduced, wherein the cams and alignment system may be more easily replaceable than the components of the conveyor.

In one aspect, the horizontal cam is positioned at a forward portion of the float frame and the horizontal cam includes a curvilinear profile having a narrow portion at the forward portion of the float frame and then tapering or widening outward toward the stationary frame to a wide portion proximate a center portion of the float frame. When the caster wheel is in an improper leading orientation, the wheel will make contact with the horizontal cam near the narrow portion and will be urged by the curvilinear profile as it progresses through the alignment system toward the wide portion of the horizontal cam such that the caster wheel is corrected from the improper leading orientation to the proper trailing orientation. Thus, the horizontal cam forces miss-oriented caster wheels to rotate about their swivel axis in order to re-orient to the proper trailing orientation.

In another aspect, the vertical cam includes a plate oriented in a vertical plane and includes an obliquely sloped first contour and a horizontal second contour. The first contour is configured to contact an axle of the transport vehicle as the transport vehicle passes the alignment system and the second contour is configured to retain the float frame in an upward or intermediate position until the axle has passed the second contour. The first contour includes a first height beginning at a forward portion of the float frame and the first contour extends or tapers to a second height proximate a center portion of the horizontal cam. The second contour is substantially horizontal and has a height equal to the second height of the first contour.

According to another form of the present invention, a method is provided for aligning the orientation of caster wheels of a conveyor having a frame, a transport vehicle have a plurality of caster wheels, and a transport vehicle support rail portion that supports the caster wheels. The method includes providing a horizontal cam coupled to a float frame and positioned to intercept a travel path of a caster wheel of the transport vehicle that travels upon the conveyor rail. The horizontal cam is configured and positioned to automatically adjust an orientation of the caster wheel from an improper leading orientation in which the caster wheel is leading an axle of the transport vehicle to a proper trailing orientation in which the caster wheel is trailing the axle. The method also includes providing a vertical cam coupled to one or both of the float frame and the horizontal cam. The vertical cam is configured and positioned to be impacted by a portion of the transport vehicle as it travels along the drive rail into contact with one or both of the cams. The method further includes causing the transport vehicle to travel into contact with one or both of the cams wherein either (i) the horizontal cam intercepts a miss-oriented caster wheel or (ii) the transport vehicle impacts the vertical cam and thereby urges the float frame to raise upward while (i) allowing the horizontal cam to adjust the orientation of an improperly leading caster wheel to a proper trailing orientation and (ii) not allowing the horizontal cam to impact the caster wheel of a transport vehicle if that caster wheel is already properly oriented in a trailing orientation.

Accordingly, the caster wheel alignment system automatically and selectively re-orients or re-positions miss-oriented caster wheels of a conveyor system transport vehicle while allowing the transport vehicle and any properly oriented caster wheels to pass through the alignment system. The system includes a horizontal cam for intercepting miss-oriented caster wheels and a vertical cam for moving the horizontal cam away from the transport vehicle to allow the vehicle to pass the alignment system. The alignment system can be installed onto a conveyor prior to the installation of the transport vehicle to automatically correct any miss-oriented caster wheels of the transport vehicle as the vehicle traverses the conveyor frame. The alignment system may preferably removed after the transport vehicle installation process is completed, however the system may be left in place indefinitely if desired.

These and other objects, advantages, purposes, and features of this invention will become apparent upon review of the following specification in conjunction with the drawings.

Referring now to the drawings and the illustrative embodiments depicted therein, a caster wheel alignment system <NUM> for a conveyor system <NUM> is provided for automatically re-orienting miss-oriented ones of swivelable caster wheels <NUM> of transport vehicles, units, trolleys, or carriers <NUM> of the conveyor system (<FIG>). The alignment system <NUM> is configured to mount to a frame <NUM> of the conveyor proximate the conveyance drive rail, track, or travel path portion <NUM> of the conveyor, such as parallel, spaced apart tracks or rails of the conveyor frame, upon which the caster wheels <NUM> travel. The alignment system <NUM> includes one or more impediment elements capable of selectively redirecting, adjusting, or re-orienting miss-oriented caster wheels <NUM> and thus preventing or eliminating potential damage to the carriers <NUM> and conveyor system <NUM> due to miss-orientation of caster wheels <NUM>. For example, improper orientation of the caster wheels <NUM> can cause increased stress on the horizontal contact wheels <NUM> of the carriers <NUM>, which are provided to guide the carriers along the inside of the track <NUM> (<FIG>, <NUM>, and <FIG>). The installation of the carriers <NUM> includes lifting and positioning them on the track <NUM> and during the lifting and positioning of the carriers <NUM>, it is possible for the caster wheels <NUM> to orient themselves in an improper position, orientation, or manner, potentially without the installation technician noticing the improper caster wheel orientation. The alignment system <NUM> is typically installed on the conveyor <NUM> during the carrier installation process and left in place until all of the carriers <NUM> have been installed and have travelled around the conveyor <NUM> at least one time, thus ensuring that all caster wheels <NUM> are properly aligned. The alignment system <NUM> may be removed from the conveyor <NUM> once installation of all carriers <NUM> is complete and may be reinstalled during maintenance of the conveyor to ensure that the caster wheels <NUM> of any removed and/or replaced carriers <NUM> are properly oriented. Optionally, the alignment system <NUM> may be left on the conveyor system indefinitely with a portion held or pinned in an upward or otherwise out of the way position such that the impediment elements will not impede or conflict with any movements of the carriers <NUM> as they move about the conveyor <NUM>.

The alignment system <NUM> is particularly well-suited for endless loop conveyor systems that utilize caster wheel supported transport carriers, as depicted in the illustrated embodiment of <FIG>, <FIG>, <FIG>, and <FIG>. Examples of such endless loop conveyor systems include circular sortation systems marketed by Dematic Corp. of Grand Rapids, MI and its affiliates, including crossbelt sorters and split tray sorters. Examples of crossbelt sorters are described in commonly owned <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>. While the caster wheel alignment system <NUM> is particularly well-suited for use in conveyor systems, it will be appreciated that the alignment system <NUM> may be adapted and utilized for substantially any system or situation where it is desirable to correct the orientation of miss-oriented caster wheels.

Referring now to the illustrated embodiment of <FIG>, a caster wheel alignment system <NUM> is provided for a conveyor <NUM> and includes a support frame having a stationary or main support frame <NUM> and a bypass system having a floating frame <NUM> that is movable relative to the stationary frame <NUM>. The system <NUM> includes one or more impediment elements or redirecting blocks, including one impediment element in the form of a horizontal cam <NUM> (<FIG>). The horizontal cam <NUM> is attached to a forward portion of the float frame <NUM>. The stationary frame <NUM> is removably attached to the frame <NUM> of the conveyor <NUM> proximate a track <NUM> (<FIG>). The float frame <NUM> is attached to the stationary frame <NUM> at a float frame guide system <NUM> (<FIG>). The float frame <NUM> is substantially freely moveable about a vertical travel path that is defined by the guide system <NUM>. The operation of the float frame <NUM> and guide system <NUM> will be discussed in further detail below. A vertical cam <NUM>, is coupled to one, or both, of the horizontal cam <NUM> and the float frame <NUM> alongside or proximate the horizontal cam <NUM> and forms a portion of the bypass system provided for moving the horizontal cam <NUM> out of the travel path of properly oriented caster wheels (<FIG>).

The horizontal cam <NUM> is positioned to impede the travel path of a caster wheel <NUM> of a carrier <NUM> that travels upon the track <NUM> (<FIG> and <FIG>). In the event that a caster wheel <NUM> is miss-oriented such that the wheel <NUM> is preceding the axle <NUM> of the carrier <NUM> when the carrier is traveling in the forward direction (see <FIG>, <FIG>, <FIG>, and <FIG>), the horizontal cam <NUM> will intercept the miss-oriented wheel <NUM> as it travels through the alignment system <NUM>. When the miss-oriented caster wheel <NUM> impacts the horizontal cam <NUM> the cam <NUM> automatically adjusts the orientation of the caster wheel <NUM> from an improper leading orientation (i.e. the caster wheel is leading the axle <NUM>, see <FIG>) to a proper trailing orientation (<FIG>) in which the caster wheel <NUM> is trailing the axle <NUM>. In the illustrated embodiments, the horizontal cam <NUM> is positioned toward a forward portion of the float frame <NUM> to intercept a miss-oriented wheel as soon as it enters the alignment system <NUM> (<FIG>). As best shown in <FIG>, the horizontal cam <NUM> includes a curvilinear profile or obliquely angled portion starting at a narrow portion 28a toward the forward portion of the float frame <NUM> and tapering laterally toward the stationary frame <NUM> to a wide portion 28b proximate to a center portion of the float frame <NUM>. As the miss-oriented caster wheel, in the improper leading orientation, makes contact with the horizontal cam <NUM> near the narrow portion 28a the wheel <NUM> is urged by the curvilinear profile as it progresses through the alignment system <NUM>. The curvilinear profile of the horizontal cam <NUM> continues to force the miss-oriented wheel to rotate about its vertical swivel axis until the wheel is sufficiently re-oriented. For example, the caster wheel <NUM> may be sufficiently re-oriented once the wheel is less than one hundred eighty degrees (<NUM>°) from its proper trailing orientation (see <FIG>). Once the miss-oriented caster wheel <NUM> is sufficiently re-oriented, the continued forward travel of the carrier <NUM> and the friction between the wheel <NUM> and the track <NUM> will continue to rotate the wheel toward its proper trailing orientation (<FIG>).

The upper portion of the caster wheels <NUM> of the carriers <NUM> occupy a common horizontal plane as a portion of the axle <NUM>. Because of this, the horizontal cam <NUM> would intercept and impact against the axle <NUM> as it travels through the alignment system <NUM>, thus preventing the carrier <NUM> from moving forward. The bypass system, in the form of a vertical cam <NUM>, is provided to eliminate the conflict between the horizontal cam <NUM> and the axle <NUM>. The vertical cam <NUM> is positioned to contact the axle <NUM> as it travels past and/or through the alignment system <NUM>. The vertical cam <NUM> is defined by a plate oriented in a vertical plane (<FIG>). The plate of cam <NUM> includes an obliquely sloped first contour 30a and a horizontal second contour 30b. The contours 30a and 30b define or set the vertical travel path that the float frame <NUM> will move about as the axle <NUM> contacts the vertical cam <NUM> (<FIG>). The first contour 30a begins at a first height proximate the forward portion of the float frame <NUM> and the first contour 30a extends to a second height proximate a center portion of the horizontal cam <NUM>. The second contour 30b is substantially horizontal and has a height equal to the second height of the first contour 30a (<FIG>).

When the axle <NUM> impacts the vertical cam <NUM> at the first contour 30a, the impact force and continued contact between the axle <NUM> and first contour 30a urges the float frame <NUM> to raise such that the horizontal cam <NUM> moves above the axle <NUM> and the caster wheel <NUM> such that the horizontal cam <NUM> does not impact the axle <NUM> as the axle <NUM> passes the horizontal cam <NUM>. The second contour 30b retains the float frame <NUM> in the upward position until the axle <NUM> has passed the second contour 30b. The vertical cam includes a third contour 30c, which permits the float frame to gradually return to its initial lowered or down position (<FIG>). The third contour 30c may have a slope equivalent to the first contour 30a, but in the reverse direction. An additional benefit to the horizontal cam <NUM> raising above the axle <NUM> is that the cam <NUM> will also pass over a properly oriented caster wheel <NUM>, thus reducing wear on the caster wheel <NUM> by eliminating unnecessary contact between properly oriented caster wheel <NUM> and the horizontal cam <NUM>. Accordingly, the vertical cam <NUM> is provided to move the float frame <NUM> in the vertical plane such that as the carrier <NUM> moves through the alignment system <NUM>, the vertical cam <NUM> contacts with the axle <NUM> and, by way of the float frame guide <NUM>, the float frame <NUM> lifts upward such that the horizontal cam <NUM> moves out of the way of and does not impact the axle <NUM>, thus allowing the carrier <NUM> to travel through and past the alignment system <NUM>.

The horizontal cam <NUM> and the vertical cam <NUM> are positioned alongside one another such that the horizontal cam <NUM> is in the lowered position long enough to intercept miss-oriented caster wheels <NUM> of carriers <NUM>. As the curvilinear profile of the horizontal cam <NUM> re-orients the miss-oriented caster wheel, the axle impact along the first contour 30a of the vertical cam <NUM> begins to urge the float frame <NUM> upward until the horizontal cam <NUM> is above the axle <NUM> of the carrier <NUM> and also above the caster wheel <NUM>. The positioning and dimensioning of the cams <NUM> and <NUM> ensure that the horizontal cam <NUM> is able to re-orient miss-oriented caster wheels while also permitting the carrier <NUM> to pass through the alignment system <NUM> without substantially impeding the movement of the carrier <NUM> along the conveyor <NUM>. It will be appreciated that different dimensions, shapes, and relative positions of the cams <NUM> and <NUM> may be provided to adjust the timing and duration of the relative actions of the cams <NUM> and <NUM> as desired or required based on the component dimensions and configurations of a particular conveyor system.

The float frame guide <NUM> of the illustrated embodiment of <FIG> includes a set of slide rails 32a that support a proximal end of the float frame <NUM> at the stationary frame <NUM>. The slide rails 32a may have a notched portion that is received in a slot defined in the float frame <NUM> and the notch and slot configuration may be substantially frictionless to allow the float frame <NUM> to move freely relative to the stationary frame <NUM>. The float frame guide <NUM> also includes a plurality of vertical guide shafts 32b, which pass through holes in the float frame <NUM> (<FIG>). The guide shafts 32b cooperate with the slide rails 32a to retain the float frame <NUM> in a substantially horizontal orientation while permitting the frame <NUM> to raise and lower vertically. It will be appreciated that while the slide rails 32a and guide shafts 32b provide stability against rotation and torsion of the float frame <NUM> relative to the stationary frame <NUM>, one of the set of slide rails 32a and plurality of guide shafts 32b may be omitted without substantially affecting the function of the float frame <NUM>. It will also be appreciated that other known guide apparatuses may be utilized to slideably couple the float frame <NUM> to the stationary frame <NUM>. While the float frame <NUM> of the illustrative embodiment is defined as moving in a vertical plane, it will be appreciated that the float frame <NUM> may be moveable in other directions to move the horizontal cam <NUM> out of the travel path of the caster wheel <NUM>. For example, the float frame <NUM> may be pivotable relative to the main frame <NUM> such that the float frame <NUM> moves about a horizontal plane to move the horizontal cam <NUM> out of the caster wheel travel path.

A key aspect of the operation of the illustrative embodiment of alignment system <NUM> is that the horizontal cam <NUM> receives substantially horizontal force from a miss-oriented wheel <NUM> and reacts with a substantially horizontal force, thus impacts between the caster wheel and the horizontal cam do not activate the vertical sliding of the float frame <NUM>. The axle <NUM>, on the other hand, applies only a substantially vertical force to the vertical cam <NUM> and the vertical cam <NUM> reacts with a substantially vertical force, thus urging the float frame <NUM> to float or move upward to allow the carriers <NUM> to pass through the alignment system <NUM>. In order to reduce or eliminate wear on the caster wheels <NUM> and axles <NUM> due to contact with the cams <NUM>, <NUM>, the cams are formed of a material having a hardness that is less than that of the wheels <NUM> and axles <NUM>. For example, the cams <NUM> and <NUM> may be formed of a relatively soft polyurethane while the caster wheels are formed of a relatively hard polyurethane and the axles are formed of a relatively hard metal. Because the cams <NUM>, <NUM> are softer than the caster wheels <NUM> and axles <NUM>, the cams will wear over time as they are impacted by the wheels <NUM> and axles <NUM>. It will be appreciated that in some embodiments the vertical cam <NUM> may be omitted without substantially affecting the function and operability of the alignment system <NUM> to redirect improperly oriented caster wheels <NUM>. It is contemplated that a bypass system may be provided with the alignment system, such as in the form of an actuation device and/or a sensor system, to permit properly oriented caster wheels to pass the horizontal cam in response to the transport vehicle passing through said alignment system. The sensor system is operable to determine whether an incoming caster wheel is improperly oriented. The actuation device is operable to move the horizontal cam, such as by raising and/or lowering the float frame or pivoting the horizontal cam, to move the horizontal cam out of the path of a properly orientated caster wheel. It will also be appreciated that the horizontal cam <NUM> may be coupled to the stationary frame in a manner such that the horizontal cam is fixed in relation to the frame of the conveyor <NUM>. In such embodiments, the float frame <NUM> may be omitted without substantially affecting the function and operability of the alignment system <NUM> to redirect improperly oriented caster wheels <NUM>.

Optionally, the alignment system <NUM> may be left on the conveyor system indefinitely and the float frame <NUM> may be pinned in an upward or intermediate position such that the impediment elements will not impede or conflict with any movements of the carriers <NUM> as they move about the conveyor <NUM>. It will be appreciated that in some embodiments, the travel path of the conveyor may constrain the rotation of a caster wheel such that the caster wheels are unable to rotate from a leading orientation to a trailing orientation (e.g. one hundred eighty degrees (<NUM>°)), such as when constrained in a c-channel, such as depicted in <FIG>, for example. In such embodiments, a portion of the travel path <NUM> and/or conveyor frame <NUM> may be substituted with the alignment system <NUM> such that the stationary frame <NUM> may permit a caster wheel to rotate from a leading orientation to a trailing orientation (e.g. one hundred eighty degrees (<NUM>°)) without being constrained by the conveyor frame <NUM>.

A method is provided for aligning the orientation of caster wheels <NUM> of a conveyor <NUM> having a frame <NUM>, a conveyance track or drive rail portion <NUM> defining a carrier or transport vehicle travel path, a carrier or transport vehicle <NUM> moveably supported on the conveyance track <NUM>, and a pair of caster wheels <NUM> of the carrier <NUM> which each travel upon respective sides of the conveyance track <NUM>. The method includes providing a wheel alignment system <NUM> including at least one impediment element in the form of a horizontal cam <NUM> coupled to a float frame <NUM> with the horizontal cam <NUM> positioned to intercept a travel path of the caster wheel <NUM> of the carrier <NUM> that travels upon the track <NUM> (<FIG>). If the caster wheel <NUM> is miss-oriented, such as in a leading orientation where the wheel <NUM> leads the axle <NUM> of the carrier <NUM>, the horizontal cam <NUM> impedes and automatically adjusts the orientation of the caster wheel <NUM> from the improper leading orientation to a proper trailing orientation in which the caster wheel <NUM> is trailing the axle <NUM>. The method also includes providing another impediment element in the form of a vertical cam coupled to either or both of the float frame <NUM> and the horizontal cam <NUM>. The vertical cam <NUM> intercepts a portion of the carrier <NUM>, such as the axle <NUM>, as the carrier <NUM> travels along the track <NUM> past and/or through the system <NUM> and into contact with one or both of the cams <NUM>, <NUM>. The method further includes causing the carrier <NUM> to travel past and/or through the cams <NUM>, <NUM> such that the carrier <NUM> will impact the vertical cam <NUM> and thereby urge or force the float frame <NUM> to raise while allowing the horizontal cam <NUM> to intercept and adjust the orientation of a misaligned caster wheel from an improper leading orientation to a proper trailing orientation and permitting the carrier <NUM> to pass the alignment system <NUM> without the horizontal cam <NUM> impacting either of the axle <NUM> or a properly oriented trailing caster wheel <NUM> of a carrier <NUM>.

Thus, the caster wheel alignment system includes a horizontal cam that is provided for intercepting and correcting the orientation of a caster wheel that is leading the axle of a transport vehicle as it traverses a conveyor system and a vertical cam that is provided for moving the horizontal cam out of the way of the transport vehicle to permit the vehicle to pass through the alignment system, such as when a subject caster wheel of the transport vehicle is in a proper trailing orientation. The horizontal cam and vertical cam cooperate with one another to effectively, selectively and automatically, re-orient improperly oriented or misaligned caster wheels without having to perform a visual inspection and without removing the transport vehicle from the conveyor track.

Claim 1:
A caster wheel alignment system (<NUM>) for a conveyor (<NUM>) having a frame (<NUM>) defining an endless loop travel path and a transport vehicle (<NUM>) having a plurality of caster wheels (<NUM>) configured to travel along the travel path, said alignment system being characterised in that it comprises:
a support frame (<NUM>) configured to couple to a portion of the frame of the conveyor;
a horizontal cam (<NUM>) coupled to said support frame and positioned to intercept a travel path of a subject one of the plurality of caster wheels of the transport vehicle that travels along the travel path, said horizontal cam configured to automatically adjust an orientation of the subject caster wheel from an improper leading orientation in which the caster wheel is leading an axle (<NUM>) of the transport vehicle to a proper trailing orientation in which the caster wheel is trailing the axle.