Patent Description:
Picking loads in warehouse or distribution centers for order fulfillment can be been challenging. Different transportation systems pick loads from a source and transport them to a destination. The transportation systems may be, for example, conveying devices or transport devices. Generally, warehouses or distribution centers for storing loads may include a storage system that comprise a series of storage racks that are accessible by the transport devices such as, but not limited to, shuttles or vertical lifts or stacker cranes that are movable within aisles along the storage racks. These transport devices may be used for storing and retrieving of loads in or from a storage rack of the storage system. Generally, the transport devices are comprised of multiple components which may be positioned on a frame and outside the frame of the transport devices which works in synergy to control movement of the transport devices and the movement of the loads handled by the transport devices. Reference may be made to <CIT> which discloses conveyor carriage movable on a guide rail, having a conveyor frame comprising a pair of side rails spaced apart from each other, a load carrying portion coupled to the pair of side rails and a plate positioned in between the pair of side rails. The plate is pivotable between an open position and a closed position, enclosing a component of the conveyor carriage in the closed position.

Reference may be made to <CIT> which relates to a device comprising a body provided with a plurality of wheels to allow translation of the device along a storage rail. First movement means are connected to the wheels to provide the motive power required for translation of the device. The device also comprises a pair of operating portions provided on opposite sides of the body with the object of defining supporting surfaces for the load unit. Reference may be made to <CIT> which relates to a kind of cam mechanism type steerable shuttle, including a shuttle vehicle body, a traveling mechanism being arranged on the vehicle body, a steering mechanism, an elevating mechanism, a battery and charging system, an electric-control system, and a communication module. Reference may be made to <CIT> which relates to an autonomous mobile robot (AMR) with a single modular platform to mount plurality of material handling units. The AMR includes a monolithic chassis; a top plate includes plurality of standoffs to mount at least one material handling units; the plurality of standoffs are integrated on top of the top plate; drive wheels are coupled to a wheel mount as a single unit to form a drive wheel assembly; a suspension unit is coupled symmetrically in between two main bodies which corresponds to the monolithic chassis and the drive wheel assembly with spring enclosures, suspension shafts, and coil springs; a set of side plates connect the monolithic chassis on the AMR. Reference may be made to <CIT> which relates to a system including a vehicle for delivering items and a moveable track that cooperates with the vehicle. The moveable track may cooperate with a storage system having storage locations for storing items. The vehicle may drive into the moveable track and lift the track using a vertical drive mechanism. Reference may be made to <CIT> which discloses a rack storage system having a plurality of storage levels and a load handling station positioned at each storage level.

The following presents a simplified summary to provide a basic understanding of some aspects of the disclosed material handling system. This summary is not an extensive overview and is intended to neither identify key or critical elements nor delineate the scope of such elements. Its purpose is to present some concepts of the described features in a simplified form as a prelude to the more detailed description that is presented later.

The present invention is defined by the appended independent claims to which reference should now be made. Specific embodiments are defined in the dependent claims.

Various example arrangements described herein relate to a conveyor carriage which includes at least one attachment bracket coupled at a bottom of the conveyor frame in between the pair of side rails beneath the load carrying portion, wherein the drop-down plate and the attachment bracket are coupled together with a hinge mechanism.

Various example arrangements described herein relate to a conveyor carriage, wherein the hinge mechanism is one of a spring-hinge or a butt-hinge.

Various example arrangements described herein relate to a conveyor carriage, wherein the component is attached on an inner surface of the drop-down plate such that the component is accessible in the open position.

Various example arrangements described herein relate to a conveyor carriage, wherein the drop-down plate further includes a locking mechanism to lock the drop-down plate with the conveyor frame in the closed position. The locking mechanism comprises spring loaded pins.

Various example arrangements described herein relate to a conveyor carriage, wherein the drop-down plate is transitioned to the open position from the closed position by retracting the spring-loaded pins.

Various example arrangements described herein relate to a conveyor carriage, wherein the load carrying portion comprises at least one of conveyor rollers or a conveyor belt or a combination thereof.

Various example arrangements described herein relate to a conveyor carriage, wherein the pair of side rails comprises a top plate attached on an upper surface of each side rail and a bottom plate attached on a bottom surface of each side rail, wherein the top plate and bottom plate extend out parallel from the side rails along a plane perpendicular to the side rails.

Various example arrangements described herein relate to a conveyor carriage, wherein the conveyor frame comprises a flared side guide attached to the top plate of each side rail.

Various example arrangements described herein relate to a conveyor carriage includes at least one sensor to detect presence of a load on the load carrying portion.

Various example arrangements described herein relate to a vertical lift including a vertical mast; a conveyor carriage; and a lifting unit to guide the conveyor carriage on the vertical mast. The conveyor carriage includes a conveyor frame comprising a pair of side rails and a load carrying portion coupled between the pair of side rails. Further, the conveyor carriage includes a pair of drop-down plates hingedly mounted to the conveyor frame and positioned in between the pair of side rails. Each drop-down plate is pivotable between an open position and a closed position, and wherein each drop-down plate encloses one or more components of the conveyor carriage in the closed position.

Various example arrangements described herein relate to a vertical lift, wherein the lifting unit includes at least one spreader to support the conveyor carriage and a set of guide rollers positioned on opposing sides of the at least one spreader, wherein the guide rollers guide the conveyor carriage on the vertical mast.

Various example arrangements described herein relate to a vertical lift, wherein each of the side rails can comprise a cut-out to facilitate mounting of the conveyor carriage on to the at least one spreader.

Various example arrangements described herein relate to a vertical lift, wherein a length of each of the drop-down plate is equal to a distance between the pair of side rails.

Various example arrangements described herein relate to a vertical lift, wherein each of the drop-down plate comprises wiring clamps mounted to an inner surface of the drop-down plate to route the wiring of the one or more components through wiring holes provided on each side rail, and wherein the wiring is housed in between a top plate and a bottom plate attached to each side rail.

Various example arrangements described herein relate to a vertical lift, wherein the drop-down plate further includes a locking mechanism to lock the drop-down plate with the conveyor frame in the closed position, wherein the locking mechanism comprises spring loaded pins.

Various example arrangements described herein relate to a rack storage system which includes a plurality of storage levels a load handling station positioned at each storage level. A control box positioned in between a guide rail and the load handling station. The control box includes a lid coupled to an end of the control box, wherein the lid is pivotable between an open position and a closed position, and wherein the lid encloses one or more components of the load handling station and bridges a gap between the guide rail and the load handling station in the closed position.

Various example arrangements described herein relate to a rack storage system, wherein the lid enables smooth transition of loads between an autonomous vehicle and the load handling station in the closed position.

Various example arrangements described herein relate to a rack storage system, wherein an end of the lid is coupled to the control box using one of hinge joints or pivot pins or mechanical fasteners.

Various example arrangements described herein relate to a rack storage system, wherein the load handling station comprises one of conveyor rollers or conveyor belts or a combination thereof to transport the loads for pick up and deposit by the autonomous vehicle.

The above summary is provided merely for purposes of summarizing some example arrangements, and to provide a basic understanding of some aspects of the disclosure. Accordingly, it will be appreciated that the above-described arrangements are merely examples and should not be construed to narrow the scope of the present invention, which is defined by the independent claims. It will be appreciated that the scope of the claims encompasses many potential embodiments in addition to those here summarized, some of which will be further described below.

Some embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. The terms "or" and "optionally" are used herein in both the alternative and conjunctive sense, unless otherwise indicated. The terms "illustrative" and "exemplary" are used to be examples with no indication of quality level.

The components illustrated in the figures represent components that may or may not be present in various embodiments of the invention described herein such that embodiments may include fewer or more components than those shown in the figures while not departing from the scope of the invention.

Turning now to the drawings, the detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts with like numerals denote like components throughout the several views.

As used herein, the terms "open position" or "opened position" may be used to refer to a position in which one or more components of a conveyor carriage or a load handling station may be accessible or visible. As used herein, the terms "closed position" or "close position" may be used to refer to a position in which one or more components of the conveyor carriage or the load handling station may be fully or partially enclosed with limited or no accessibility to the one or more components. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention, which is defined by the independent claims.

As used herein, the term "gap" may be used to refer to a space created between guide tracks of the autonomous vehicle and the load handling station due to the structural arrangement of the storage racks and vertical lifts which may pose difficulty in picking or depositing loads from or to the load handling station. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

As used herein, the terms "pick-up" or "store" or "deposit" or "retrieve" may collectively refer to various operations performed by the vertical lifts and the autonomous vehicle in the rack storage system. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

As used herein, the term "load handling station" may be used to refer to a pick-up and deposit (P&D) conveyor or infeed/outfeed conveyor or buffer conveyor which can support and convey loads using one or more conveying elements. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

As used herein, the terms "guide track" or "guide rail" or "support rail" may be used to refer to guideways or pathways through which the vertical lifts and the autonomous vehicle are guided to store and retrieve the loads. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

As used herein, the terms "storage system", "retrieval system", "rack storage system", "automated storage and retrieval system" may be used to refer to any portion of a warehouse or a distribution center having multiple storage racks with a provision to store and retrieve one or more loads. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

As used herein, the terms "infeed station", "outfeed station" may be used to refer to a goods to operation station or conveyors operating in conjunction with the goods to operator station. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

As used herein, the terms "plates", "braces", "brackets", "mounts", "side guide", "side rail" may be used to refer to structural elements with provisions to mechanically couple with other structural elements of a mechanical system or an electrical system.

As used herein, the terms "loads" or "load" may be used to refer to items, products, articles, packages, baggage, luggage, storage containers such as trays, totes, cartons, boxes, or pallets. Thus, use of any such terms should not be taken to limit the scope of embodiments of the present invention.

Generally, a storage and retrieval system may be provided as a two-dimensional or three-dimensional storage and retrieval system. Such storage and retrieval system are often referred to as Automated Storage and Retrieval System (ASRS or AS/RS). In such automated storage and retrieval system, throughput is always a concern due to increase in storage and retrieval times. Further, retrieving loads from the storage racks in a quick and efficient manner has been a constraint in most of the automated storage and retrieval system. Typically, the transport devices may be movable in vertical directions and horizontal directions within the aisles which is defined between two adjacent storage racks for storing and retrieving the loads. Each storage rack may be of a predefined height configured with multiple storage levels with predefined depth to store the loads picked up by the transport devices. One such transport device which can move vertically at different heights between the multiple storage levels is a vertical lift.

In some examples, the loads transported to/from the storage levels are contained in storage containers such as trays, totes, cartons, boxes or on pallets. Depending on a storage capacity of the storage racks, the racks may be known as high density racks or ultra-high-density racks. Such storage containers are stored in the storage racks and retrieved from the storage racks using the vertical lift for performing operations such as, for example, order fulfilment or replenishment or building mixed pallets. While vertical lifts of various configurations have been proposed to store and retrieve the loads or storage containers for fulfilling such operations in a warehouse or a distribution center, the prior known configurations of the vertical lifts have certain drawbacks. Some of the considerations while designing the configurations of the vertical lifts to overcome the prior drawbacks are: minimize the storage and retrieval time; maximize safety in handling loads during storage and retrieval by minimizing slippage, misalignment and jam, minimize wear and tear of components of the vertical lifts by modifying the configuration/arrangement to handle overload, stress, vibrations, derailing and other external factors affecting the lifespan and safety of the vertical lifts and its components.

Through applied effort, ingenuity, and innovation, many of the above identified problems have been solved by developing solutions that are included in embodiments of the present invention, many examples of which are described in detail herein. The present disclosure relates to a conveyor carriage and a load handling station installed in a vertical lift structure with a configuration to maximize safety of the loads and various components of the conveyor carriage and the load handling station while minimizing maintenance. According to an embodiment, the conveyor carriage and the load handling station are a part of the storage and retrieval system capable of storing loads at multiple storage levels. According to an embodiment, the conveyor carriage includes a drop-down plate hingedly mounted to a conveyor frame and pivotable between an open position and a closed position. According to another embodiment, the load handling station includes a control box with a lid pivotable between a closed position and an open position. According to an embodiment, the lid and the drop-down plate encloses various components of the load handling station and the conveyor carriage respectively in the closed position for minimizing wear and tear of the various components when operating in the storage and retrieval system.

According to an embodiment, the lid may act as a slidable support when an autonomous vehicle retrieves the loads from the load handling station while protecting the components from damage.

According to an embodiment, the control box positioned adjacent the load handling station to bridge a gap between the load handling station and a guide track of the autonomous vehicle.

According to an embodiment, the conveyor carriage includes a locking mechanism to lock the drop-down plate with the conveyor frame in the closed position.

According to an embodiment, the load handling station comprises one of conveyor rollers or conveyor belts or a combination thereof to transport the loads for pick up and deposit by the autonomous vehicle.

According to an embodiment, the drop-down plate and the lid is pivoted to the open position to access the various components of the conveyor carriage and the load handling station.

According to an embodiment, the conveyor carriage and the load handling station may include sensors to align the conveyor carriage with the load handling station and to detect presence of a load on the conveyor carriage and the load handling station.

In the following detailed description, specific representative embodiments in which the present invention may be practiced are described in sufficient detail to enable those skilled in the art to practice the disclosed embodiments. For example, specific details such as specific method orders, structures, elements, and connections have been presented herein. However, it is to be understood that the specific details presented need not be utilized to practice embodiments of the present invention. It is also to be understood that other embodiments may be utilized and that logical, architectural, programmatic, mechanical, electrical and other changes may be made without departing from the scope of the appended claims. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

Throughout this specification, the terms 'conveyors' or 'conveyor devices' or 'conveyor system' may be used interchangeably and these terms should be taken as an example of both roller conveyor, a belt conveyor, or their combination.

Throughout this specification, the terms `rollers' or 'conveyor rollers' may be used interchangeably and the term 'belt' or 'conveyor belt' may be used interchangeably and should be taken as an example of a medium which transports loads on the conveyor system.

Throughout this specification, the terms 'hinged' or hingedly' or 'transitioned' or `pivoted' or `pivotable' may be used interchangeably and should be taken as an example of a provision provided to a component such as a lid or a plate to rotate from one position to another position.

Throughout this specification, the terms 'storage and retrieval system' or `rack storage system' may be used interchangeably and should be taken as an example of a system having storage racks.

Generally, storage and retrieval system operate under computerized control, maintaining an inventory of stored loads. Retrieval of loads is accomplished by specifying the load type and quantity to be retrieved. The computer determines where in the storage area the load can be retrieved from and schedules the retrieval. The autonomous vehicles and the vertical lifts are sometimes part of the storage and retrieval system. In some storage and retrieval system, the horizontal movement in the storage racks within the system is made by independent shuttles each operating on one level of the storage rack while the vertical lift at a fixed position within the storage rack is responsible for the vertical movement. In some storage and retrieval system, the autonomous vehicle picks up or drops off loads at specific load handling stations in the storage area provided along with the storage rack. Inbound and outbound loads are precisely positioned for proper handling in the load handling stations. Various aspects of the present invention are described in connection with conveyor carriages used with the vertical lifts and the load handling stations of the storage and retrieval system to ensure safe handling of the loads.

Referring now specifically to the drawings and the illustrative embodiments depicted therein, <FIG> discloses a perspective view of a dual conveyor carriage <NUM> on two different vertical lift structures <NUM>, <NUM>, in accordance with an embodiment of the present invention. <FIG> discloses an embodiment of the dual conveyor carriage <NUM> mounted to a vertical lift structure <NUM> having a central support rail <NUM> and <FIG> discloses another embodiment of the dual conveyor carriage <NUM> mounted to a vertical lift structure <NUM> having dual support rails 106a, 106b, one rail 106a installed in parallel with the other rail 106b with two conveyor carriages <NUM> positioned in between the rails. Both configurations of the vertical lift as shown in <FIG> includes two conveyor carriages <NUM> independently movable on the support rail <NUM> or rails 106a, 106b to handle loads stored in the storage racks of the storage and retrieval system, however, it is conceivable to use a single conveyor carriage on the vertical lift structures <NUM>, <NUM> as shown in <FIG>. According to an embodiment, a first conveyor carriage 102a and a second conveyor carriage 102b on the vertical lift structures <NUM>, <NUM> may pick up and deposit the loads between the load handling stations on the storage racks and outfeed stations/infeed stations. In some examples, the first conveyor carriage 102a may be employed to pick and deposit the loads at load handling stations of a first set of storage levels and the second conveyor carriage 102b may be employed to pick and deposit the loads at load handling stations of a second set of storage levels. In some examples, both the first conveyor carriage 102a and the second conveyor carriage 102b may be employed to pick and deposit the loads at the load handling stations of any of the storage levels of the storage rack. In some examples, the first conveyor carriage 102a may pick the loads from the infeed station and deposit the loads at a load handling station of a selected storage level and the second conveyor carriage 102b may pick the loads from the load handling station of the selected storage level and deposit the loads at the outfeed station. In some examples, both the first conveyor carriage 102a and the second conveyor carriage 102b may simultaneously pick and deposit the loads from or to the load handling station, the infeed station, and the outfeed station. In some examples, both the first conveyor carriage 102a and the second conveyor carriage 102b may pick the loads from the infeed station and deposit the load at a common load handling station at a selected storage level without collision between the first conveyor carriage 102a and the second conveyor carriage 102b. Similarly, both the first conveyor carriage 102a and the second conveyor carriage 102b may pick the loads from the common load handling station at the selected storage level and deposit the loads at the outfeed station without collision between the first conveyor carriage 102a and the second conveyor carriage 102b. Such configurations of the dual conveyor carriages <NUM> operating in the storage and retrieval system to pick and deposit the loads without any collision is disclosed in <CIT>. A perspective view of a rack storage system with the storage racks and the load handling stations is shown in <FIG> and <FIG>.

According to an embodiment, the first conveyor carriage 102a and the second conveyor carriage 102b are driven independently using driving systems. The driving systems may include drive belts <NUM>, drive pulleys 110a, 110b, and drive motors <NUM>. The drive belts <NUM> are received for vertical rotation respectively on a pair of top drive pulleys 110a and received independently on a pair of bottom drive pulleys 110b, wherein the bottom drive pulleys 110b are driven by a pair of drive motors <NUM>. The drive motors <NUM> independently rotate the bottom drive pulleys 110b to independently control movement of the first conveyor carriage 102a and the second conveyor carriage 102b. According to an embodiment, as shown in <FIG>, the drive belts are installed on the support rail <NUM> or rails 106a, 106b. In <FIG>, the drive belts <NUM> are installed on the parallel support rails 106a, 106b, one drive belt on each support rail 106a, 106b and in <FIG> the drive belts <NUM> are installed on the central support rail <NUM>. According to an embodiment, the drive belts <NUM> facilitate the movement of the first conveyor carriage 102a and the second conveyor carriage 102b on the support rail <NUM> or rails 106a, 106b under the influence of the drive motors <NUM>. In some examples, the drive motors <NUM> include a motor encoder to track a position of the first conveyor carriage 102a and the second conveyor carriage 102b when guided on the support rail <NUM> or rails 106a, 106b. According to an embodiment, as shown in <FIG>, each support rail 106a, 106b is mounted to a pair of vertical mast <NUM>. For example, a first support rail 106a may be positioned in between a first pair of vertical mast 114a and a second support rail 106b positioned in between a second pair of vertical mast 114b. The first support rail 106a and the second support rail 106b mounted to the first pair of vertical mast 114a and the second pair of vertical mast 114b respectively using mounting brackets <NUM>. According to an embodiment, the first support rail 106a and the second support rail 106b are mounted to a pair of top housings <NUM> and a bottom housing <NUM> common for the first support rail 106a and the second support rail 106b. For example, one end of the first support rail 106a and the second support rail 106b may be attached to a first set of attachment plates <NUM> on the pair of top housings <NUM> and other end of the first support rail 106a and the second support rail 106b may be attached to a second set of attachment plates <NUM> on the bottom housing <NUM>, wherein the attachment plates <NUM>, <NUM> ensures proper alignment of the first support rail 106a and the second support rail 106b. In some examples, the bottom housing <NUM> may include components such as the drive motors <NUM>, bottom drive pulleys 110b, bearings (not shown), and bottom spreader <NUM>. In some examples, the pair of top housings <NUM> may include components such as the top drive pulleys 110a, bearings (not shown), top spreader <NUM>, and a pair of access plates <NUM> for maintenance of the components inside the top housings <NUM>. According to an embodiment, the first conveyor carriage 102a and the second conveyor carriage 102b positioned in between the top housings <NUM> and the bottom housing <NUM> are driven independently using the components inside the top housings <NUM> and the bottom housing <NUM>. According to an embodiment, the first conveyor carriage 102a and the second conveyor carriage 102b may be positioned in the vertical lift structure having a single common support rail without any housings for the components as disclosed in <CIT>. Considering the first conveyor carriage 102a and the second conveyor carriage 102b being structurally identical, <FIG> discloses a top perspective view of a conveying carriage <NUM> on the vertical lift structure <NUM> of <FIG>. According to embodiment, the conveyor carriage <NUM> depicted in <FIG> may also be used on the vertical lift structure <NUM> as shown in <FIG>. According to an embodiment, the conveyor carriage <NUM> depicted in <FIG> may also be used on any vertical lift structure generally known in the art including provisions to install and guide the conveyor carriage <NUM>.

According to an embodiment, the conveyor carriage <NUM> includes a conveyor frame <NUM>, a pair of side rails 210a, 210b, a load carrying portion <NUM>, an attachment bracket <NUM>, and a drop-down plate <NUM>. According to an embodiment, the load carrying portion <NUM> of the conveyor carriage <NUM> may be configured to support the load. According to an embodiment, the load carrying portion <NUM> may be configured to transfer the load to the load handling station. In some examples, the load carrying portion <NUM> includes one or more conveying elements, such as, but not limited to, conveyor rollers <NUM>, conveyor belt <NUM> or their combination to support and transfer the load to the load handling station. In the embodiment shown in <FIG>, the load carrying portion <NUM> includes a plurality of conveyor rollers <NUM> with a conveyor belt <NUM> wrapped around the rollers <NUM>. According to an embodiment, the rollers <NUM> include at least one motorized drive roller (MDR). The MDR may drive the conveyor belt <NUM> wrapped around the rollers <NUM> to facilitate movement of the load. In some examples, the MDR may be positioned in between the plurality of rollers <NUM> and linked to neighboring conveyor rollers <NUM> using O-Bands <NUM>. In some examples, the MDR may be positioned as an end roller <NUM> or next to the end roller and linked to neighboring conveyor rollers <NUM> using the O-Bands <NUM>. According to an embodiment, the load carrying portion <NUM> may include two sets of conveyor rollers <NUM> wrapped around independently using two conveyor belts <NUM> with each set of conveyor rollers <NUM> having at least one MDR to drive the conveyor belts <NUM>. Such a configuration enables the two sets of conveyor rollers <NUM> wrapped independently by two conveyor belts <NUM> to be considered as two different conveyor zones 204a, 204b which are independently controlled to move the load into or out of the load handling station. As shown in <FIG>, the load carrying portion <NUM> is coupled to the conveyor frame <NUM> and sandwiched between the pair of side rails 210a, 210b of the conveyor frame <NUM>. The pair of side rails 210a, 210b include a first side rail 210a and a second side rail <NUM>0b, each rail having a plurality of slots (not shown) to receive the load carrying portion <NUM>. For example, axles (not shown) of the rollers <NUM> are seated on corresponding slots in the pair of side rails 210a, 210b in a parallel uniform arrangement from an upstream side <NUM> of the conveyor carriage <NUM> to a downstream side <NUM> of the conveyor carriage <NUM>. According to an embodiment, the rollers may be coupled to cartridge frames with side plates and arcuate sloped surfaces as disclosed in <CIT> with the cartridge frames being attached to the pair of side rails 210a, 210b using suitable fasteners. In some examples, the cartridge frames may be attached to the pair of side rails 210a, 210b using axle retainers as disclosed in <CIT>.

According to the invention, the conveyor frame <NUM> further includes a top plate <NUM> attached on an upper surface of each side rail 210a, 210b and a bottom plate <NUM> attached on a bottom surface of each side rail 210a, 210b, and the top plate <NUM> and the bottom plate <NUM> extend out parallelly from the side rails 210a, 210b along a plane perpendicular to the side rails 210a, 210b. For example, the top plate <NUM> and the bottom plate <NUM> form right angles with a side surface of the side rails 210a, 210b when the top plate <NUM> and the bottom plate <NUM> are attached to the upper surface and the bottom surface of the side rails 210a, 210b. According to an embodiment, the conveyor frame <NUM> further includes a side guide <NUM> attached to the top plate <NUM> of each side rail 210a, 210b. For example, the side guide <NUM> may be fastened to the top plate <NUM> on each side rail 210a, 210b using suitable fasteners. According to an embodiment, the side guide <NUM> on the top plate <NUM> of each side rail 210a, 210b may be flared at opposing ends of the side guide <NUM>. For example, the side guide <NUM> on the upstream side <NUM> and the downstream side <NUM> of the conveyor carriage <NUM> may be flared to enable smooth movement of the loads into conveyor carriage <NUM> from the upstream side <NUM> and out of the conveyor carriage <NUM> from the downstream side <NUM>. In some examples, the side guide <NUM> is formed by coupling multiple guide portions 218a, 218b, 218c with each other throughout a length of the conveyor carriage <NUM> from the upstream side <NUM> to the downstream side <NUM>. For example, the side guide <NUM> may include a first guide portion 218a, a second guide portion 218b and a third guide portion 218c. The first guide portion 218a provided on the upstream side <NUM> of the conveyor carriage <NUM> and the third guide portion 218c provided on the downstream side <NUM> of the conveyor carriage <NUM> and the second guide portion 218b provided between the first guide portion and the third guide portion 218c. The first guide portion 218a and the third guide portion 218c may be flared. According to an embodiment, one or more sensors may be positioned on the side guide <NUM> to detect presence of the load on the load carrying portion <NUM>. For example, the side guide <NUM> may include one or more sensor mounts 224a with a corresponding opening 224b for positioning the one or more sensors <NUM> on the side guide <NUM>. The one or more sensors <NUM>, for example, may be optical sensors such as photoeye sensors, laser sensors, infrared sensors, ultraviolet sensors, or the like configured to detect the presence of the load on the load carrying portion <NUM>. In some examples, a vision sensor such as a camera may be installed on the side guide <NUM> to detect the presence of the load.

According to an embodiment, the conveyor frame <NUM> further includes a front bracket <NUM> and a back bracket <NUM> attached to the top plate <NUM> and the bottom plate <NUM> of each side rail 210a, 210b. The front bracket <NUM> is provided at the upstream side <NUM> of the conveyor carriage <NUM> and fastened to one end of the top plate <NUM> and the bottom plate <NUM>. Similarly, the back bracket <NUM> is provided at the downstream side <NUM> of the conveyor carriage <NUM> and fastened to other end of the top plate <NUM> and the bottom plate <NUM>. According to an embodiment, the front bracket <NUM>, the back bracket <NUM>, the top plate <NUM>, and the bottom plate <NUM> are coupled together to form a protective housing for various components and wirings/cables of the various components of the conveyor carriage <NUM>. The coupling of the brackets <NUM>, <NUM> and plates <NUM>, <NUM> may be enabled using any suitable fasteners known in the art.

According to an embodiment, the conveyor carriage <NUM> is vertically guided on the vertical lift structure <NUM> of <FIG> using a lifting unit <NUM>. According to an embodiment, the conveyor carriage <NUM> and the lifting unit <NUM> together form the vertical lift <NUM>, <NUM> as shown in <FIG> and <FIG>. As shown in <FIG> and <FIG>, the lifting unit <NUM> includes a first set of guide rollers 312a mounted on a first pair of roller mounting plates <NUM>, a second set of guide rollers 312b mounted on a second pair of roller mounting plates <NUM>, a pair of spreaders <NUM>, a first spreader mounting plate <NUM> with an outer surface 308a coupled to the first pair of roller mounting plates <NUM> and an inner surface 308b coupled to one end of the pair of spreaders <NUM>, a second spreader mounting plate <NUM> with an outer surface coupled to the second pair of roller mounting plates <NUM> and the inner surface 308b coupled to another end of the pair of spreaders <NUM>. According to an embodiment, the lifting unit <NUM> may include only one spreader connecting the first spreader mounting plate <NUM> with the second spreader mounting plate <NUM>. The first set of guide rollers 312a and the second set of guide rollers 312b are guided on the support rails 106a, 106b of the vertical lift structure <NUM> of <FIG>. The lifting unit <NUM> is driven vertically by the drive belt <NUM> installed on the support rails 106a, 106b. According to an embodiment, the conveyor carriage <NUM> is seated on top of at least one spreader 311and capable of moving vertically with the lifting unit <NUM>. For example, each of the side rails 210a, 210b of the conveyor frame <NUM> includes a cut-out <NUM> to facilitate mounting of the conveyor carriage <NUM> on the at least one spreader <NUM>. According to an embodiment, the lifting unit <NUM> may include a belt tensioner module <NUM> attached to the first spreader mounting plate <NUM> and the second spreader mounting plate <NUM> to adjust a tension of the drive belt <NUM> driving the conveyor carriage <NUM>. In some examples, the belt tensioner module <NUM> may include tensioner springs to adjust the tension of the drive belt <NUM>. According to an embodiment, one or more additional sensors <NUM> may be positioned on the front bracket <NUM> or the back bracket <NUM> to position the conveyor carriage <NUM> with the load handling station when conveyor carriage <NUM> is vertically guided on the vertical masts 114a, 114b. The one or more additional sensors <NUM> includes, for example, photoeye sensors, laser sensors, infrared sensors, ultraviolet sensors, vision sensors or the like configured to detect the presence of the load handling station and stop the conveyor carriage <NUM> to initiate transfer of the load to the load handling station.

According to an embodiment, the drop-down plate <NUM> is attached to the conveyor frame <NUM>. According to an embodiment, the drop-down plate <NUM> is hingedly attached to the conveyor frame <NUM> using the attachment bracket <NUM>. According to the invention, the drop-down plate <NUM> is hingedly attached to the conveyor frame <NUM> using the bottom plate <NUM> on each side rail 210a, 210b. According to an embodiment, as shown in <FIG>, a pair of drop-down plates 302a, 302b may be attached to the conveyor frame <NUM> with one drop-down plate <NUM> at the upstream side <NUM> of the conveyor carriage <NUM> and with other drop-down plate <NUM> at the downstream side <NUM> of the conveyor carriage <NUM>. According to an embodiment, the pair of drop-down plates 302a, 302b is hingedly attached to the conveyor frame <NUM> using a pair of attachment brackets 304a, 304b. According to another embodiment, the pair of drop-down plates 302a, 302b is hingedly attached to the conveyor frame <NUM> using the bottom plate <NUM> on each side rail 210a, 210b. According to the invention, the drop-down plate <NUM> is coupled to the bottom plate <NUM> with a hinge mechanism <NUM>. The hinge mechanism <NUM>, for example, is a butt-hinge or spring-hinge as known in the art. As shown in <FIG>, one leaf 318b of the hinge is fastened to the attachment bracket <NUM> and other leaf 318a of the hinge to the drop-down plate <NUM> to enable hinged connection between the attachment bracket <NUM> and the drop-down plate <NUM>.

According to an embodiment, as shown in <FIG>, the drop-down plate <NUM> includes a locking mechanism <NUM> to lock the drop-down plate <NUM> with the conveyor frame <NUM>. The locking mechanism <NUM>, for example, includes spring-loaded pins <NUM> and finger rings <NUM>. The spring-loaded pins <NUM> and the finger rings <NUM> are attached to an inner surface <NUM> of the drop-down plate <NUM> while an outer surface <NUM> of the drop-down plate <NUM> is attached to the hinge mechanism <NUM>. In some examples, the locking mechanism <NUM> may include magnets on the inner surface <NUM> to hold the drop-down plate <NUM> with the conveyor frame <NUM> with a magnetic attraction force. According to an embodiment, as shown in <FIG>, the drop-down plate <NUM> further includes a pair of access openings <NUM> provided formed integrally on the drop-down plate <NUM>. The pair of access openings <NUM> are formed adjacent and overlapping the finger rings <NUM>. The pair of access openings <NUM> are provided to access the finger rings <NUM> on the inner surface. For example, the pair of access openings <NUM> facilitates an operator to reach the finger rings <NUM> from the outer surface of the drop-down plate <NUM>. According to an embodiment, as shown in <FIG>, the drop-down plate <NUM> further includes mounting apertures <NUM> and wiring clamps <NUM> provided on the inner surface of the drop-down plate <NUM>. The mounting apertures <NUM> are provided to mount one or more components of the conveyor carriage <NUM> to the inner surface <NUM>. According to an embodiment, the one or more components <NUM> include, but not limited to, control components 502a, I/O components 502b, communication components 502c, and power components 502d. Further, the wiring clamps <NUM> are provided to route the wiring of the one or more components <NUM> through wiring holes provided on each side rail 210a, 210b, wherein the wiring is further routed through additional clamps <NUM> provided on each side rail 210a, 210b. According to an embodiment, the wiring may be housed in between the top plate <NUM> and the bottom plate <NUM> attached to each side rail 210a, 210b. Such a configuration with wiring clamps <NUM> and wiring holes is provided for ease of installation, maintenance, and safety.

According to an embodiment, the drop-down plate <NUM> is pivoted from a closed position to an open position and vice-versa. For example, the drop-down plate <NUM> may transition to the open position and the closed position using the hinge mechanism <NUM>. <FIG> shows a view of the drop-down plate <NUM> in the closed position, and <FIG> shows a view of the drop-down plate <NUM> in the open position. According to an embodiment, the drop-down plate <NUM> encloses the one or more components <NUM> of the conveyor carriage <NUM> in the closed position. According to an embodiment, the one or more components <NUM> attached to the mounting apertures <NUM> on the inner surface of the drop-down plate <NUM> is accessible in the open position. According to an embodiment, the drop-down plate <NUM> is locked in the closed position with the conveyor frame <NUM> using the locking mechanism <NUM> as shown in <FIG>. For example, the finger rings <NUM> on the inner surface attached to the spring-loaded pins <NUM> can be retracted by the operator through the access openings <NUM> from the outer surface when the drop-down plate <NUM> is in the open position. After pivoting the drop-down plate <NUM> to the closed position, the retracted finger rings <NUM> may then be released by the operator such that the spring-loaded pins <NUM> are seated into a corresponding locking aperture (not shown) provided on the side rails 210a, 210b. In this manner, the drop-down plate <NUM> may be locked with the conveyor frame <NUM> using the spring-loaded pins <NUM> and the finger rings <NUM>. According to an embodiment, the inner surface <NUM> of the drop-down plate <NUM> and the load carrying portion <NUM> may be provided with a clearance that is substantially equal to a distance 'X' between the top plate <NUM> and the bottom plate <NUM> on each side rail 210a, 210b as shown in <FIG>. Such a clearance is provided to ensure that a risk of accidental contact between the one or more components <NUM> and the load carrying portion <NUM> is eliminated when the drop-down plate <NUM> is in the closed position. According to an embodiment, the clearance may be substantially equal to a height 'H' of the front bracket <NUM> or the back bracket <NUM> as shown in <FIG>. According to an embodiment, the drop-down plate <NUM> may have a 'C' shaped or a 'U' shaped profile. According to another embodiment, the drop-down plate <NUM> may be a flat plate.

According to an embodiment, the drop-down plate <NUM> is released from the conveyor frame <NUM> using the locking mechanism <NUM> to pivot the drop-down plate <NUM> from the closed position to the open position. For example, the finger rings <NUM> attached to the spring-loaded pins <NUM> can be retracted through the access openings <NUM> such that the spring-loaded pins <NUM> that are seated into the corresponding locking aperture provided on the side rails 210a, 210b is moved out of contact with the aperture transitioning the drop-down plate <NUM> to the open position. In some examples, a spring-hinge may be used as the hinge mechanism <NUM> to gradually transition the drop-down plate <NUM> to the open position upon releasing the spring-loaded pins <NUM> from the locking aperture. <FIG> show a view of the pair of drop-down plates 302a, 302b in the open position with the one or more components <NUM> of the conveyor carriage <NUM> mounted in a distributed manner between the pair of drop-down plates 302a, 302b. For example, <FIG> shows a view of one of the pair of drop-down plates 302a, 302b in which the I/O components 502b, the power components 502d and the communication components 502c are mounted and FIG. 6B shows a view of one of the pair of drop-down plates 302a, 302b in which the control components 502a are mounted. According to an embodiment, a single drop-down plate <NUM> may be provided on the conveyor carriage <NUM> for mounting the I/O components 502b, the power components 502d, the communication components 502c, and the control components 502a. In some examples, the power components 502d may include a power filter to transfer and filter power from a power rail supplying power to the conveyor carriage <NUM>. In some examples, the communication components 502c may include a communication modem and bus transmitter enabling ethernet communication. In some examples, the control components 502a may include a motor driven roller (MDR) control card to control the drive rollers of the conveyor carriage <NUM>. In some examples, the I/O components 502b may include I/O modules with M8 connections or M12 connections or their combination to receive cables/wirings from sensors and the control card. Such components <NUM> are enclosed within the conveyor frame <NUM> of the conveyor carriage <NUM> using the drop-down plate <NUM> such that the components <NUM> are not subjected to wear and tear during an operation of the conveyor carriage <NUM>. Further, such components <NUM> are fixedly attached to the drop-down plate <NUM> which is locked with the conveyor frame <NUM> such that the components <NUM> are not subjected to jerks or vibration or accidental damage during an operation of the conveyor carriage <NUM>. Further, such components <NUM> are made accessible by pivoting the drop-down plate <NUM> from the closed position to the open position facilitating ease of maintenance.

<FIG> discloses a perspective view of a rack storage system <NUM> in which the vertical lift structure <NUM> of <FIG> is installed, in accordance with an embodiment of the present invention. Further, <FIG> discloses a perspective view of a rack storage system <NUM> in which the vertical lift structure <NUM> of <FIG> is installed, in accordance with an embodiment of the present invention. The rack storage system <NUM>, <NUM> as shown in <FIG> and <FIG> include multi-level storage racks <NUM>, load handling stations <NUM>, <NUM>, a vertical lift <NUM>, <NUM> with a conveyor carriage <NUM>, and an autonomous vehicle <NUM> as shown in <FIG>. According to an embodiment, multiple autonomous vehicles <NUM>, each servicing storage racks <NUM> at one storage level or storage racks <NUM> at multiple storage levels may be employed. According to an embodiment, the vertical lift structure <NUM>, <NUM> including the vertical lift <NUM>, <NUM> may be installed adjacent to the load handling stations <NUM>, <NUM>. One load handling station may be provided at each storage level which may be located adjacent the storage racks <NUM>. The vertical lift <NUM>, <NUM> may deposit a load <NUM> at a selected load handling station of a selected storage level and the load <NUM> may then be picked by the autonomous vehicle <NUM> to store the load <NUM> at a selected storage rack <NUM>. According to an embodiment, the autonomous vehicle <NUM> may travel laterally or vertically on guide tracks <NUM> within the rack storage system <NUM>, <NUM> to reach the selected storage rack <NUM>. According to an embodiment, the vertical lift may retrieve a load <NUM> deposited by the autonomous vehicle <NUM> at the load handling station after retrieving the load <NUM> from the storage rack <NUM>. Therefore, the load handling stations <NUM>, <NUM> may handle loads <NUM> which are to be stored in the storage racks <NUM> or retrieved from the storage racks <NUM>. According to an embodiment, the load handling stations <NUM>, <NUM> may include one or more conveying elements to support and transfer the load <NUM> deposited or retrieved by the vertical lift <NUM>, <NUM> or the autonomous vehicle <NUM>. A sectional top view of one such load handling station used with the rack storage system <NUM> of <FIG> is disclosed in detail in <FIG>.

As shown in <FIG>, the load handling station <NUM> may include two conveyor zones <NUM>, <NUM><NUM>, <NUM> with one or more conveying elements to support and transfer the load <NUM> deposited or retrieved by the vertical lift <NUM><NUM> or the autonomous vehicle <NUM>. According to an embodiment, the two conveyor zones <NUM>, <NUM> may serve as both an infeed zone for receiving load <NUM> from the vertical lift <NUM> and an outfeed zone discharging the loads <NUM> to the vertical lift <NUM>. According to an embodiment, the two conveyor zones <NUM>, <NUM> may serve as a buffer zone to temporarily store the loads <NUM> for retrieval by the autonomous vehicle <NUM> or the vertical lift <NUM>. The two conveyor zones <NUM>, <NUM> may be mounted to a common conveyor frame <NUM> and attached to a pair of mounting braces 805a, 805b. The pair of mounting braces 805a, 805b includes a first mounting brace 805a attached to the vertical masts 114a, 114b of the vertical lift <NUM> and a second mounting brace 805b attached to the storage rack <NUM> of the rack storage system <NUM>. According to an embodiment, the two conveyor zones <NUM>, <NUM> may be attached to the first mounting brace 805a without any additional mounting braces for support. As shown in <FIG>, the pair of mounting braces 805a, 805b may be positioned in between the guide tracks <NUM> of the autonomous vehicle <NUM>. For example, the autonomous vehicle <NUM> may travel on the guide tracks <NUM> provided within the rack storage system <NUM> to reach the two conveyor zones <NUM>, <NUM> of the load handling station <NUM> to deposit or retrieve the load <NUM>. According to an embodiment, the two conveyor zones <NUM>, <NUM> may include at least one motorized drive roller (MDR) to drive the conveyor and move the load <NUM> from one conveyor zone <NUM> to another conveyor zone <NUM>. For example, the load <NUM> may be deposited by the vertical lift <NUM> to a first conveyor zone <NUM>, which may then move the load <NUM> to the second conveyor zone <NUM> using the MDR of the first conveyor zone <NUM>. In some examples, the load <NUM> may be deposited by the autonomous vehicle <NUM> to the second conveyor zone <NUM>, which may then move the load <NUM> to the first conveyor zone <NUM> using the MDR of the second conveyor zone <NUM>. According to an embodiment, the second conveyor zone <NUM> may include a load stop <NUM> to stop an overtravel of the load <NUM> moving from the first conveyor zone <NUM> on to the second conveyor zone <NUM>. According to an embodiment, the two conveyor zones <NUM>, <NUM> may include a plurality of rollers <NUM> with at least one motorized drive roller (MDR) and a belt <NUM> wrapped around rollers <NUM>. The MDR provided in each conveyor zones <NUM>, <NUM> drives the load <NUM> from one conveyor zone <NUM> to another conveyor zone <NUM> and vice-vera. According to an embodiment, the two conveyor zones <NUM>, <NUM> may include one or more sensors (not shown) to detect a presence of the load <NUM> on the conveyor zones <NUM>, <NUM>. For example, the MDR of the conveyor zones <NUM>, <NUM> may be activated to move the load <NUM> from one conveyor zone <NUM> to another conveyor zone <NUM> only after detecting the presence of the load <NUM>.

According to an embodiment, one or more components <NUM> for controlling the load handling station <NUM> is attached to a control box <NUM>. As shown in <FIG>, the control box <NUM> positioned in between one of the guide tracks <NUM> and the load handling station <NUM>, however, conceivable are other arrangements in which two control boxes <NUM> are employed, each positioned on either side of the load handling station <NUM> and in between the guide tracks <NUM>. According to an embodiment, the control box <NUM> may include a base frame <NUM> and a lid <NUM>. The base frame <NUM> is fastened to the guide track <NUM> using a mounting bracket <NUM>, for example, a 'L' shaped mounting bracket as shown in <FIG>. The one or more components <NUM> are attached to the base frame <NUM> using suitable fasteners known in the art. For example, the one or more components <NUM> may be control components such as MDR cards for controlling the motorized drive rollers on the conveyor zones. For example, the one or more components <NUM> may be I/O communication components with M8 or M12 connections to receive cables/wirings of the one or more sensors and the MDR cards. According to an embodiment, the lid <NUM> and the base frame <NUM> are coupled to each other using one of hinge joints or pivot pins or mechanical fasteners. In the example, shown in <FIG>, ends of the lid <NUM> are coupled to the ends of the base frame <NUM> using a pin hinge <NUM>. Pins at the ends of the lid <NUM> are seated on corresponding holes on the base frame <NUM> to form a hinged connection. According an embodiment, the lid <NUM> is pivoted between a closed position and an open position with respect to the base frame <NUM>. For example, the pin hinge <NUM> forming the hinge connection may facilitate pivotal movement of the lid <NUM> such that the lid <NUM> can be closed and opened. According an embodiment, the lid <NUM> may enclose the one or more components <NUM> attached to the base frame <NUM> when the lid <NUM> is in the closed position. Such a configuration protects the one or more components <NUM> from wear and tear. According to an embodiment, the lid <NUM> may be pivoted to the open position when the one or more components <NUM> require to be accessed for maintenance. According to an embodiment, the base frame <NUM> may include a pair of wiring holes <NUM> to route the wirings/cables of the one or more components <NUM> inside the control box <NUM>. According to an embodiment, the lid <NUM> is locked with the base frame <NUM> using a locking mechanism. The locking mechanism, for example, may be a bolt-latch lock, a magnetic lock, a snap fit lock, or any locking mechanism known in the art. In <FIG>, an example of the snap fit lock is provided in which grooves <NUM> on the ends of the lid <NUM> snaps with protrusions <NUM> provided on the base frame <NUM>. According to an embodiment, the locking mechanism <NUM> to lock the drop-down plate <NUM> with the conveyor frame <NUM> may be used to lock the lid <NUM> with the base frame <NUM>.

According an embodiment, the control box <NUM> positioned adjacent the load handling station <NUM> bridges a gap <NUM> between the load handling station <NUM> and the guide track <NUM>. For example, as shown in <FIG>, the gap <NUM> between the conveyor zones <NUM>, <NUM> and the guide track <NUM> is filled by the installation of the control box <NUM> in the gap <NUM>. Such a configuration may enable the autonomous vehicle <NUM> travelling on the guide track <NUM> to smoothly retrieve or deposit the load <NUM> from or to the load handling station <NUM> without being caught in the gap <NUM>. As shown in <FIG>, the autonomous vehicle <NUM> travels on the guide track <NUM> and retrieves the load <NUM> placed on the second conveyor zone <NUM> using load handling arms <NUM> of the autonomous vehicle <NUM>. For example, the autonomous vehicle <NUM> shown in <FIG> is a shuttle vehicle. According to an embodiment, the lid <NUM> of the control box <NUM> enables smooth transition of the load <NUM> between the autonomous vehicle <NUM> and the load handling station <NUM> when the lid <NUM> is in the closed position. For example, the lid <NUM> may be made of smooth material such as a polished metal or transparent glass to enable the load <NUM> to slide over the lid <NUM> at ease when retrieved by the load handling arms <NUM> of the autonomous vehicle <NUM>. Thus, the lid <NUM> may be used for protecting the one or more components <NUM> of the load handling station <NUM> and for enabling the smooth transition of the load <NUM> between the load handling station <NUM> and the autonomous vehicle <NUM>. <FIG> shows the autonomous vehicle <NUM> accessing the load <NUM> from one side of the load handling station <NUM> installed with the control box <NUM>, however, other arrangements in which, two control boxes <NUM>, one on each side of the load handling station <NUM> may be feasible to bridge the gaps <NUM> between the guide tracks <NUM> and the load handling station <NUM> while making provisions for the autonomous vehicle <NUM> to access the load <NUM> from both sides of the load handling station <NUM> without being caught in the gaps <NUM>. Such an arrangement may allow the components <NUM> to be distributed between the two control boxes <NUM> facilitating ease of maintenance of the components. Therefore, the control box <NUM> with the pivotable lid <NUM> may ensure safety of both the load <NUM> handled by the load handling station <NUM> and the components <NUM> operating the load handling station <NUM>.

The distributed control architecture and control logic for controlling the vertical lifts, the autonomous vehicle, and the load handling station are disclosed in <FIG> and <FIG> of <CIT>.

Claim 1:
A conveyor carriage (<NUM>) movable on a guide rail, wherein the conveyor carriage (<NUM>) comprises:
a conveyor frame (<NUM>) comprising a pair of side rails (210a, 210b) spaced apart from each other, wherein the pair of side rails (210a, 210b) comprises a top plate (<NUM>) attached on an upper surface of each side rail and a bottom plate (<NUM>) attached on a bottom surface of each side rail, wherein the top plate (<NUM>) and bottom plate (<NUM>) extend out parallel from the side rails along a plane perpendicular to the side rails;
a load carrying portion (<NUM>) coupled to the pair of side rails (210a, 210b);
a drop-down plate (<NUM>) positioned in between the pair of side rails (210a, 210b) and hingedly attached, via a hinge mechanism (<NUM>), to the conveyor frame (<NUM>) using the bottom plate on each side rail, wherein the drop-down plate (<NUM>) is pivotable between an open position and a closed position, and wherein the drop-down plate (<NUM>) encloses a component of the conveyor carriage (<NUM>) in the closed position.