Automated forming of cast polyurethane

Cast polyurethane parts for shoes or other items may be formed in an automated fashion. A dispensing mechanism may dispense a predetermined amount of a liquid phase polyurethane mixture onto a flat surface face of a mold. A dispersal mechanism may distribute the liquid phase polyurethane mixture over the flat surface face of the mold to fill at least one cavity in the form. A vacuum may be applied to remove air bubbles from the liquid phase polyurethane mixture. Excess liquid phase polyurethane mixture may be removed from the flat surface face of the mold using a flexible blade that contacts and moves across the flat surface face. One or more conveyance mechanism may transport molds through the desired stages of a system and/or method in accordance with the present invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

FIELD

The present invention relates to materials, systems, and/or methods for forming cast polyurethane. More particularly, the present invention relates to the automated production of cast polyurethane parts for use in shoes and other items.

BACKGROUND

Cast polyurethane is a useful component of many products, such as shoes. Cast polyurethane possesses properties, such as being relatively pliable and light weight, that make useful for constructing various items and/or component parts of items. The ability to form polyurethane into a desired shape, size, and configuration desired is particularly useful. However, the known processes for forming cast polyurethane are undesirably inefficient and wasteful. For example, in conventional cast polyurethane forming methods workers using straight edges, squeegees, or the like must repeatedly scrape the liquid phase polyurethane to distribute the polyurethane within a mold cavity and remove excess polyurethane from the face of the mold. The excess polyurethane removed by manual scraping is typically unable to be reused, leading to undesirable waste. In addition to repeated and labor intensive manual scraping steps that waste liquid polyurethane, the liquid polyurethane must be repeatedly subjected to a vacuum force to draw air bubbles out of the liquid. Typically, a scraping step must be performed both before and after each vacuum step, which further increases the labor cost and material waste of forming cast polyurethane. Further, the irregularities of a largely manual process of forming cast polyurethane can lead to irregular product quality, unpredictable product performance, and excessive rejections by quality control evaluation.

SUMMARY

Polyurethane is a useful material utilized in a variety of products such as shoes and, more particularly, athletic shoes. Polyurethane may be used for a variety of purposes in an athletic shoe, such as, but not limited to, soles, midsoles, uppers, structural supports, functional elements on a shoe upper, decorative components, and the like. Polyurethane components in a shoe may be formed using molds to retain a liquid phase polyurethane mixture for curing to create a cast polyurethane part. Cast polyurethane may be referred to as “CPU.” Forming cast polyurethane has traditionally been a labor-intensive process. However, manually forming cast polyurethane for shoe parts can lead to irregular and unpredictable characteristics for the resulting parts, as well as requiring additional training and other precautions for the workers involved in forming the cast polyurethane.

Accordingly, systems and methods in accordance with the present invention for the automated forming of cast polyurethane are described herein. Cast polyurethane may be formed using a mold or form with one or more cavities corresponding to the size and shape of the cast polyurethane part to be formed. The mold may have a substantially flat surface face below which the cavity extends. A mold used in accordance with the present invention may move through a system in accordance with the present invention on a conveyance mechanism, such as a sequence of pushers and rollers, a conveyor belt, or any other conveyance mechanism at a predetermined rate or rates. The mold may pause and/or be retained in place at various stations in order for operations to be performed on the polyurethane and/or the mold. A mold may be retained in place using stops, blocks, rails, clamps, or other mechanisms that retain a mold in place while operations are performed on the mold and/or polyurethane on or within the mold. The rate at which an individual mold progresses through a system may vary based upon the portion of the system that the mold is encountering, quality control demands, performance requirements, and the like. A mixing station may combine the component materials of liquid polyurethane, an isocyanate and a polyol, as part of or immediately prior to a liquid phase polyurethane mixture dispensing system. A liquid phase polyurethane mixture dispensing system may dispense liquid polyurethane into the cavity and/or onto the substantially flat surface face of a mold in accordance with the present invention. Various approaches may be used to attain a desired distribution and amount of polyurethane over the face of a mold, such as by using nozzles having a desired distribution pattern that moves dispensers relative to the face of a mold to dispense polyurethane over the face in a desired pattern. For example, a dispensing nozzle may distribute liquid polyurethane in a predetermined amount, at a predetermined rate, and/or in a predetermined pattern so as to fill the cavity of the mold substantially completely with little or no excess liquid polyurethane beyond the amount needed to fill the cavity. By controlling the amount of liquid phase polyurethane mixture dispensed and/or the pattern in which the liquid phase polyurethane mixture is dispensed over the flat surface face of the mold to correspond to the at least one cavity in the mold, the waste of polyurethane may be reduced and the quality of cast polyurethane parts produced may be improved as compared to prior polyurethane processes.

A system in accordance with the present invention may further disperse polyurethane over the face of a mold, for example by using moving air to spread the liquid phase polyurethane mixture across the face of the mold after the liquid phase polyurethane mixture has been deposited. Moving air may be applied by a blower, an air knife, a compressed air source, or other mechanism. Air may be applied at a predetermined angle or angles that serves to move or spread polyurethane in a desired direction(s) within a cavity and/or on the flat surface face of the mold. Additionally/alternatively, a vibration unit such as a shake table may be used to disperse liquid phase polyurethane mixture within a cavity and/or on the flat surface face of the mold. A vacuum system may apply a vacuum to the flat surface face of the mold and the liquid phase polyurethane mixture to extract air bubbles from the liquid phase polyurethane. The vacuum system may interface with the mold to establish a substantially air tight seal, thereby permitting an extremely low pressure to be applied to the liquid polyurethane extracting air bubbles from the liquid polyurethane in a single application rather than multiple applications.

A system in accordance with the present invention may further provide a flexible blade, such as a squeegee, to force the liquid phase polyurethane mixture into the cavity of the mold and/or to remove excess liquid polyurethane from the face of the mold. The mold may be retained in place while the flexible blade contacts and moves across the flat surface face of the mold. Alternatively, the flexible blade may be positioned such that a conveyance mechanism moves the mold beneath the flexible blade such that the flat surface face of the mold contacts at least the edge of the blade as the mold is moved to cause the flexible blade to cross the flat surface face. Various manners of biasing mechanisms, such as springs, pneumatic cylinders, and the like, may be used to bias the flexible blade and/or the mold and/or conveyance mechanisms towards one another to adequately engage the flexible blade against the flat surface face of the mold. A flexible blade may engage the face of a mold at a predetermined angle or angles that is the same as, different from, or related to the angle or angles at which moving air is applied. A flexible blade may, for example, be applied at an angle or in a direction opposing the direction of application of the moving air, which may aid in the uniform distribution of liquid polyurethane in a mold. A cleaning unit may clean residual liquid polyurethane from the flexible blade at appropriate intervals, such as after each use, every five uses, every ten minutes, etc.

In various implementations of systems and methods in accordance with the present invention, these various components may be ordered in different ways, duplicated, or omitted. Further, heating or other curing devices may be used to facilitate the formation of solid polyurethane from the liquid phase polyurethane mixture used in accordance with the present invention. For example, an oven, heating mat, heating table, heat press, or other type of heating device may be used to heat a mold to facilitate partial or complete curing of the liquid phase polyurethane mixture in the cavity of the mold.

Systems and/or methods in accordance with the present invention may pre-clean molds prior to use (by scrubbing or air blowing, for example), treat molds with release agents or the like, inspect molds prior to use, etc. Further, in systems and methods in accordance with the present invention equipment may be provided to remove a cured polyurethane piece from a mold and to clean a form for re-use, if desired.

Methods in accordance with the present invention may convey molds having at least one cavity extending below a flat surface face of the mold through a series of stations or components of a system to form cast polyurethane molds conveyed may be moved so as to maintain the flat surface face in a substantially horizontal orientation. A predetermined amount of a liquid phase polyurethane mixture may be dispensed in a predetermined pattern onto the flat surface face of the mold and/or into the at least one cavity of the mold. The predetermined amount of liquid polyurethane mixture dispensed may correspond to the volume of at least one cavity, and the predetermined pattern in which the liquid phase polyurethane mixture is dispensed may correspond to the configuration and location of the at least one cavity of the mold. The dispensed liquid phase polyurethane mixture may be dispersed, for example using moving air, to facilitate filling of the at least one cavity of the mold. A vacuum may be applied to the liquid phase polyurethane mixture to extract bubbles from the liquid phase polyurethane mixture. Excess liquid phase polyurethane mixture may be removed from the flat surface face of the mold using a flexible blade that contacts and moves across the flat surface face of the mold. The flexible blade may be periodically cleaned to remove liquid phase polyurethane mixture. Additional steps, such as mold preparation, polyurethane curing, de-molding cast polyurethane parts, and the like may also be incorporated in such a method.

DETAILED DESCRIPTION

The present invention provides systems and methods for forming cast polyurethane. While the present invention is described herein for examples of forming cast polyurethane for use as parts in constructing athletic shoes, the systems and methods in accordance with the present invention may be used for forming cast polyurethane parts for use in other types of shoes or even for products other than shoes. The particular formulation, type, physical properties, chemical properties, etc. of polyurethane desired may vary based upon the properties desired for the product ultimately incorporating the polyurethane part and the purpose of the cast polyurethane part in the finished product. Different types of polyurethane parts may benefit from different types of mold materials, dispensing mechanisms, dispersing mechanisms, curing techniques, and the like. These variations are within the scope of the present invention, although only particular examples are described herein.

Referring now toFIG. 1, a system100for forming cast polyurethane is schematically illustrated.FIG. 1does not depict example system100to scale. System100is merely one general example of various components that may be used for forming cast polyurethane in accordance with the present invention. Other configurations, combinations, arrangements, additions, modifications, and/or omissions of the example components illustrated inFIG. 1may be made. WhileFIG. 1illustrates a linear system100, in any implementations other configurations may be desirable. For example, a system for forming cast polyurethane in accordance with the present invention may effectively form a loop that moves molds repeatedly through a process of forming cast polyurethane parts and then prepares the molds for re-use. Systems in accordance with the present invention may also vary from the example system100shown inFIG. 1in that components may be added, omitted, or modified beyond the examples illustrated in system100. In some examples of systems in accordance with the present invention, components may operate independently from one another. Further, a system in accordance with the present invention may provide various paths for forming a cast polyurethane part, with a part in processing moving to the next component most available (for example, with the shortest queue of parts awaiting processing) rather than simply proceeding in a substantially linear fashion as described in the examples herein.

As depicted inFIG. 1, a mold120may be moved along a conveyance mechanism110to permit system100to form a cast polyurethane part. Mold120may be constructed of aluminum or any other material with the resiliency, durability, thermodynamic properties, etc., required for the forming of a particular type of cast polyurethane. Mold120may, if desired, be preheated or prechilled to a desired temperature for optimal cast polyurethane forming conditions.FIG. 1does not depict any type of form preparation component, but such components may be a part of a system in accordance with the present invention. Mold120may have at least one cavity122extending beneath a flat surface face124. While only a single cavity122is illustrated within mold120in the example ofFIG. 1, additional cavities may be present. Cavity122may ultimately correspond to the size and shape of the desired cast polyurethane part. Conveyance mechanism110is shown as a conveyor belt in the example ofFIG. 1, but may be any type of conveyance mechanism, such as chain drive system, a system of rollers, a pusher system, or any other device that moves mold120through system100may transport mold120as indicated by arrow101through system100.FIG. 15, which is described further below, depicts an example of a system in accordance with the present invention wherein a pusher and roller system is used to convey molds.

While the schematic example ofFIG. 1is illustrated in a substantially linear fashion, a system100in accordance with the present invention may be organized in a circle, square, vertically, a non-linear fashion, or in any other configuration with different constituent parts of the system100arranged as appropriate for the particular application of the invention. For example, instead of a single conveyance mechanism110, multiple conveyance mechanisms may be used to transport a mold120to various stations of a system in accordance with the present invention, potentially with a mold such as mold120spending longer amounts of time in some portions of the system rather than others, such as an extended amount of time in an oven for curing of polyurethane. InFIG. 1a first stop102, a second stop104, and a third stop106are illustrated. Stops102,104,106may comprise any type of mechanism or structure that retains a mold120in place for processes to be performed upon the mold and/or polyurethane on/in the mold.

A liquid phase polyurethane mixture dispensing system130may apply a predetermined amount of a liquid phase polyurethane mixture into the cavity122of a mold120and/or onto the flat surface face124of mold120in a predetermined dispersal pattern when conveyance mechanism110moves mold120into an appropriate position. As indicated by axes139, dispensing mechanism may be capable of moving in three dimensions to distribute a liquid phase polyurethane mixture on a form in a desired pattern appropriate for the part to be formed. The amount of liquid phase polyurethane mixture dispensed and/or the pattern in which the liquid phase polyurethane mixture is dispensed may correspond to the size and/or location of cavity122, in order to facilitate the efficient filling of cavity122. Conveyance mechanism110may pause when mold120is appropriately positioned, or a mold may be retained by stopper102. Alternatively or additionally, a mold120may be moved off of conveyance mechanism110and into position for dispensing system130, or dispensing system130may dispense a liquid phase polyurethane mixture into the cavity122and/or upon the flat surface face124of mold120as mold120is moved by conveyance mechanism110.

Dispensing component130may comprise a nozzle132that receives liquid phase polyurethane mixture for dispensing. Due to the chemical properties of polyurethane, a reservoir may comprise multiple compartments that contain different components, typically at least an isocyanate and a polyol, that are mixed as needed for dispensing by, for example, nozzle132. For example, a first compartment134may contain an isocyanate and a second compartment135may contain a polyol. A first tube136may transport the isocyanate from the first compartment134, and second tube137may transport the polyol from the second compartment135, although additional compartments and/or tubes may be used for additional components or additives such as color agents, that may be desired. First tube136and second tube137, as well as any additional tubes, may transport components to a mixing unit131that mixes the components (for example, by agitation, stirring, etc.) to form a liquid phase polyurethane mixture. The resulting liquid phase polyurethane mixture may have materials present in addition to merely polyurethane, such as desired additives, unreacted isocyanate and/or polyol, and/or impurities. Alternatively, first compartment134and second compartment135may dispense materials to mixing unit without tubes, or already mixed liquid polyurethane may be provided from a reservoir to a dispensing nozzle132. As explained more fully below, dispensing station130and nozzle132may distribute a predetermined amount of liquid phase polyurethane mixture in a dispersal pattern into the cavity122and/or over the flat surface face124of mold120. These dispersal patterns may be selected, in part, based upon the size and shape of the cavity122to be filled with liquid phase polyurethane mixture by system100in order to reduce the waste of polyurethane in the process of forming cast polyurethane. While a single cavity122is illustrated within a single mold120inFIG. 1, in practice a single mold may provide multiple cavities for use in forming cast polyurethane in accordance with the present invention.

A dispersal mechanism138may distribute the dispensed liquid phase polyurethane mixture in an appropriate pattern within the cavity122and/or over the flat surface face124of mold120. Dispersal mechanism138may comprise, for example, an air blower or an air knife that uses moving air to distribute the dispensed liquid phase polyurethane mixture across the flat surface face124of the mold120. An alternative and/or additional dispersal mechanism138may be a vibrational unit, such as a shake table. Dispersal mechanism138may be omitted entirely if nozzle132or other liquid phase polyurethane mixture dispensing mechanism distributes liquid polyurethane over the flat surface face124of mold120in a manner that is acceptable to adequately fill the cavity122used to form an eventual cast polyurethane part. Dispersal mechanism138may be part of the dispensing component130, but dispersal mechanism138may comprise an entirely separate component of system100. Further, dispersal mechanism138may constitute a plurality of similar or different mechanisms, such as multiple air knives and/or vibrational units, that operate to distribute liquid polyurethane across a flat surface face124of a mold120. A dispersal mechanism138such as a blower, air knife, or the like may be oriented at a distance from the flat surface face of, for example, between 20 and 40 millimeters, may produce an air speed of between 5 and 20 meters per second, and may be positioned at an angle139of between 45 and 90 degrees relative to the flat surface face124. The angle at which moving air approaches the dispensed liquid phase polyurethane mixture and the flat surface face124of a mold120may serve to move the liquid phase polyurethane mixture in a predetermined direction and distance within the cavity122and/or over the face124of a mold120. Such movement of liquid polyurethane may be accounted for in determining the dispensing pattern used by dispensing component130in order to efficiently fill the cavity122with the liquid phase polyurethane mixture.

A vacuum system159may comprise a vacuum generator152that applies a reduced air pressure to the liquid phase polyurethane mixture on a mold120via a vacuum chamber150to extract air bubbles from the liquid phase polyurethane mixture. While the example schematic ofFIG. 1illustrates the vacuum chamber150located after the dispersal mechanism138and before flexible blade140when a mold120is transported by conveyance mechanism110in the direction indicated by arrow101, other configurations and/or orders of components may be used. A hose154may connect a vacuum-generating unit152to a vacuum chamber150. Hose154may comprise a vacuum hose or duct in many implementations of the present invention. A vacuum chamber150may move vertically as indicated by axis151to engage a mold120with an opening or mouth shaped to mate with mold120to provide a reasonably air-tight seal over a mold120to facilitate the extraction of air bubbles from the liquid phase polyurethane mixture on mold120and/or in cavity122of mold120. Alternatively/additionally, vacuum chamber150may form a seal with the surface underlying mold120, which may comprise a conveyance mechanism110such as a conveyor belt, a table that retains a mold120at the vacuum station, etc. Vacuum chamber150may form a temporary seal with a mold120while mold120is retained in position by stop104, and may use seals, gaskets, clamps, etc. to attain a sufficiently air tight seal. Vacuum chamber150may be moveable as indicated by axis151so as to engage and disengage a mold120during the process. The duration of application and the power of the vacuum applied may vary. In one example, a vacuum may be applied for a total of thirty seconds, with a pressure of 10 torr attained in 13.5 seconds.

In the present example illustrated inFIG. 1, as conveyance mechanism110moves a mold120through system100, after the liquid phase polyurethane mixture has been distributed over the flat surface face124of mold120and after bubbles have been removed from the liquid phase polyurethane mixture by the vacuum150, a flexible blade140may be used to remove excess remaining liquid phase polyurethane mixture from the flat surface face124of mold120and/or to force the liquid phase polyurethane mixture into cavity122extending below flat surface face124of mold120. Flexible blade140may comprise, for example, a squeegee within a holder142. Holder142may be operable to move in at least two dimensions, as indicated by axes149, in order to contact flexible blade140to flat surface face124of mold120and to move the flexible blade140over flat surface face124of mold120while mold120is retained by stopper106. Alternatively, holder142may maintain the positioning of flexible blade140relative to the conveyance mechanism110and/or a mold120being moved by conveyance mechanism110to permit mold120to be moved so as to bring flexible blade140into contact with and across flat surface face124of mold120. In the example illustrated inFIG. 1, blade140engages the flat surface face124of mold120at an angle149less than ninety degrees, but angles of other magnitudes and/or varying magnitudes may be used in accordance with the present invention. Further, multiple flexible blades140may be used to provide adequate coverage of the entire flat surface face124of a mold120, or a single flexible blade140may be used over different locations in multiple passes to provide adequate removal of excess liquid phase polyurethane mixture from a flat surface face124. A flexible blade140may optionally move the liquid phase polyurethane mixture in the opposite direction that moving air from a dispersal mechanism138moved the liquid polyurethane mixture to further assure an even distribution of the liquid phase polyurethane mixture within a cavity122.

One or more biasing mechanisms may bias flexible blade140or mold120(or conveyance mechanism110carrying mold120) toward one another to engage blade140against flat surface face124of mold120. Biasing mechanisms may comprise springs, pneumatic cylinders, etc. Alternatively, a holder142may rigidly maintain a flexible blade140in a position that adequately engages flat surface face124of mold120without a need for a biasing mechanism.

In various examples of systems and methods in accordance with the present invention, a cleaning mechanism may be optionally provided to remove remaining liquid phase polyurethane mixture from a flexible blade140. A variety of cleaning mechanisms or combinations of cleaning mechanisms may be used in accordance with the present invention. For example, a cleaning mechanism may be used that moves to a flexible blade140that remains stationary in its position relative to the remainder of system100after a mold120has been scraped by blade140. Alternatively, a flexible blade140may be moved to be engaged by a cleaning mechanism and then repositioned for the next operation of the flexible blade140. Flexible blade140may be constructed of a variety of materials, such as artificial or natural rubbers, flexible metals, composites, and the like. Depending upon the types of materials used for a flexible blade140, different types of cleaning mechanisms constructed of different materials may be selected. For example, a cleaning mechanism may utilize one or more brush that engages flexible blade140. A brush or brushes may optionally rotate to facilitate in removing remaining liquid phase polyurethane mixture from a flexible blade140. Another example of a cleaning mechanism is a nozzle that applies compressed air at a predetermined force, rate, and/or angle to blow liquid polyurethane from the flexible blade140. By way of further example, water or other solvents may be sprayed to remove liquid polyurethane from a flexible blade140, or a flexible blade140may be submerged partially or entirely in a bath of water and/or another solvent to remove excess liquid phase polyurethane mixture. Yet another example of a possible cleaning mechanism is a vibrating mechanism that will induce vibrations to a flexible blade140to vibrate residual liquid phase polyurethane mixture from the flexible blade140. Further, multiple types of cleaning mechanisms may be used simultaneously and/or serially to obtain a desired level of cleanliness of a flexible blade140. In one example, one or more air nozzles may spray air at an angle along the length of blade140while one or more rotating circular brushes engage along the length of the blade140. For example, a flexible blade140may be moved to insert into a solvent bath, after which flexible blade140may be vibrated and engaged by a water spray. After being engaged by a water spray, a flexible blade140may be engaged by rotating brushes to finish the cleaning of the flexible blade. Depending upon the type of flexible blade used, the properties of the liquid phase polyurethane mixture dispensed in accordance with the present invention, and/or the cleanliness tolerances required for a particular application of the present invention, any number of cleaning mechanisms may be used on a flexible blade140at any desired regularity. For example, a flexible blade140may be cleaned after each use, after every five uses, at hour intervals, or at any other regularity appropriate for a particular use of systems and methods in accordance with the present invention.

Conveyance mechanism110may ultimately transport a mold120along the direction indicated by arrow101to additional components, some of which are described more fully below. For example, additional stations of a system in accordance with the present invention may pre-cure a liquid phase polyurethane mixture, cure the liquid phase polyurethane mixture, apply additional components such as textiles to the polyurethane, remove cast polyurethane from a mold, clean molds, apply mold release agents to molds for future use, pre-chill or pre-heat molds for future use, quality control or inspection stations for cast polyurethane and/or molds, etc.

A computing device190having a processing unit191executing instructions from a computer readable media192may monitor and/or control the operation of one or more component of system100via connections198. Computing device190may have an output device(s)194and an input device(s)196to permit a human user to evaluate or modify the performance of system100. Computing device190may be connected to a network199, thereby permitting various components of system100and/or computing device190itself to be located remotely from other components. Connections198and to network199may be wireless or wired and may use any protocol to monitor and/or control system100or to provide/receive information from a human user. Any type of input device196and output device194may be used, such as devices that may function both to provide outputs and to receive inputs, such as touchscreens.

Referring now toFIG. 15, a further example of a system1500in accordance with the present invention is illustrated. System1500in the example ofFIG. 15resembles system100in the example ofFIG. 1, except that system1500uses rollers1510and at least one pusher1505as a conveyance mechanism instead of the conveyor belt110shown in the example ofFIG. 1. Other exemplary components depicted in the example ofFIG. 15may resemble the corresponding exemplary components described above with regard to the example ofFIG. 1.

Referring now toFIG. 2, a further example of a dispensing mechanism is illustrated. In the example illustrated inFIG. 2, a first nozzle232dispenses a first stream212of a liquid phase polyurethane mixture while a second nozzle233dispenses a second stream of a liquid phase polyurethane mixture213over a mold120and into cavity122. The distance between a nozzle232,233and mold120may be selected based upon the properties desired for the liquid phase polyurethane mixture distributed in the streams212,213, with a shorter distance reducing the number of bubbles formed in the liquid phase polyurethane mixture and reducing the spread of each of the liquid phase polyurethane mixture streams212,213before contacting the mold120. The example arrangement illustrated inFIG. 2may, for some examples, attain a satisfactory distribution of liquid phase polyurethane mixture over the flat surface face124of mold120such that all portions of cavity122are engaged, thereby precluding the need to use a dispersal mechanism138, or reducing the functionality required for such a dispersal mechanism138.

Referring now toFIG. 3, a further example of a dispensing mechanism in accordance with the present invention is illustrated. In the example shown inFIG. 3, a single nozzle332dispenses a stream312of liquid phase polyurethane mixture into cavity122and/or onto flat surface face124of mold120. As indicated inFIG. 3, nozzle332may be actuated in both a first direction341and a second direction342to facilitate the distribution of the liquid phase polyurethane mixture over a flat surface face124of mold120. As indicated by axes139inFIG. 1, however, a nozzle such as nozzle332may be movable in all three dimensions, allowing nozzle332to widely and precisely distribute a stream of liquid phase polyurethane mixture within cavity124. If actuated vertically, the distance between nozzle332and mold120may be varied during distribution of the liquid phase polyurethane mixture, if desired. For some example applications, a nozzle332that may be actuated in multiple directions may provide adequate distribution of a liquid phase polyurethane mixture over the surface face124of mold120to adequately engage all portions of cavity122. If such is the case, a dispersal mechanism138may potentially be omitted or may be reduced in functionality.

Referring now toFIG. 4, a further example of a nozzle432is shown schematically above a form120with a cavity122. In the example shown inFIG. 4, nozzle432may move along two axis, such that nozzle432may move in a first direction441and in an opposing second direction442along a first axis, and nozzle432may further move in a third direction443and in an opposing fourth direction444along a second axis. Optionally, nozzle432may move along another axis, in this example closer or further to mold120, or may move to tilt at an angle relative to mold120. Such mobility of nozzle432may permit the dispensing of a liquid phase polyurethane mixture over a surface face124and/or into a cavity122of a mold120in an efficient pattern. Further, by precisely controlling the amount of polyurethane mixture dispensed by nozzle432, whether by weight, or by volume, or both, waste of polyurethane may be reduced without impairing the quality of the resulting cast polyurethane parts due to the precise placement of the liquid phase polyurethane mixture within the cavity122of a mold120.

Referring now toFIG. 5, an example mold120with liquid phase polyurethane mixture512dispensed over at least a portion of the flat surface face124and into at least a portion of cavity122is illustrated. The example illustrated inFIG. 5may be attained in any of a number of fashions, such as, but not limited to, the examples illustrated inFIGS. 2-4above. As can be seen from the example illustrated inFIG. 5, liquid phase polyurethane mixture512extends beyond the flat surface face124of mold120, rather than being limited merely to cavity122corresponding to the part to be formed from polyurethane. As described herein, further components in accordance with the present invention may function to distribute liquid phase polyurethane mixture throughout the cavity122of mold120and remove any excess liquid phase polyurethane mixture from the flat surface face124of the mold120. The amount of liquid phase polyurethane mixture dispensed into cavity122may be selected so as to minimize the amount of polyurethane used beyond the minimum necessary to fill cavity124while also providing a sufficient amount to assure that the cavity122is fully filled. The precise positioning of liquid phase polyurethane mixture during the dispensing may enable less waste of polyurethane while still attaining a complete filling of a cavity124with liquid phase polyurethane mixture. The actual amount of liquid phase polyurethane mixture dispensed relative to the size of a cavity122may vary from that illustrated inFIG. 5, which is for illustrative purposes only. As also illustrated inFIG. 5, a plurality of bubbles550may be introduced into the liquid phase polyurethane mixture before or during the dispensing process. Such bubbles550may undermine the consistency and structural qualities of the finished cast polyurethane product and, therefore, may be removed prior to curing the polyurethane as described herein.

Referring now toFIG. 6, a mold120having therein a cavity122is illustrated. Mold120and cavity122are merely examples. The cavity122illustrated inFIG. 6may correspond to any type of part desired for a shoe or other item. The example shown inFIG. 6is exemplary only, with actual molds120and actual cavities122used in accordance with the present invention being able to take any of a variety of forms, depending upon the item to be ultimately manufactured and the desired size, shape, properties, etc. of the ultimately formed cast polyurethane part. As indicated by arrow101, mold120may be moving as indicated through a system such as system100. As shown in the example ofFIG. 6, a single dispensing nozzle132has applied a predetermined amount of a liquid phase polyurethane mixture512in a predetermined pattern over the flat surface face124of mold120. Both the amount and pattern used to dispense the liquid phase polyurethane mixture512corresponds to the size and configuration of cavity122. Any of a variety of dispensing mechanisms, such as but not limited to those described with regard toFIGS. 2-4may be used in accordance with the present invention. As can be seen in the example ofFIG. 6, a predetermined amount of liquid phase polyurethane mixture512has been dispensed in a pattern that places most of the dispensed liquid polyurethane within cavity122. As also shown inFIG. 6, dispensed liquid phase polyurethane mixture512may have a large number of bubbles550. As shown inFIG. 6, the direction of movement101by conveyance mechanism110has not yet brought mold120to the dispersal mechanism138.

Referring now toFIG. 7, a mold120with a cavity122therein is illustrated after a dispersal mechanism138has distributed the liquid phase polyurethane mixture712over the flat surface face124of mold120. As can be seen from comparing the dispensed liquid phase polyurethane mixture512inFIG. 6to the dispersed liquid phase polyurethane mixture712inFIG. 7, dispersal mechanism138has distributed the liquid phase polyurethane mixture across the flat surface face124of mold120such that the entirety of cavity122is covered without a large amount of the liquid phase polyurethane mixture needlessly distributed over the flat surface face124of mold120. As described above, dispersal mechanism138may comprise a blower, air knife, vibration unit, or other types of mechanisms that distributes liquid phase polyurethane mixture over the flat surface face124. As can be further seen in the example illustrated inFIG. 7, the liquid phase polyurethane mixture has been moved from the pattern in which it was dispensed (for example as illustrated inFIG. 6) to distribute the liquid phase polyurethane mixture within cavity122. As also shown in the example ofFIG. 7, at least some of the distributed liquid phase polyurethane mixture712extends beyond the cavity122and onto the flat surface face124of the mold120.

Referring now toFIG. 8, a vacuum chamber150has engaged a mold120and/or a surface beneath a mold120with a liquid phase polyurethane mixture712filled cavity to generate a vacuum over the flat surface face124of mold120. The reduced air pressure of the applied vacuum results in bubbles550illustrated in prior figures being extracted from the liquid phase polyurethane mixture712in the cavity122of mold120. The configuration illustrated inFIG. 8for applying a vacuum to a mold120may occur at different stages of the process and at different positions relative to the other components described herein, but in the present example occurs after the application of a dispersal mechanism138and before application of a flexible blade140.

Referring now toFIG. 9, a flexible blade140retained in a holder142has removed excess liquid phase polyurethane mixture from the flat surface face124of mold120and forced liquid phase polyurethane mixture into cavity122such that the only remaining liquid phase polyurethane mixture812fills cavity122. In the present example, a vacuum has already removed bubbles from the liquid phase polyurethane mixture. As indicated by arrow901, mold120has been retained in place while blade140has been moved across the face124of mold120in direction901, which moves liquid phase polyurethane mixture in the opposite direction (relative to cavity122) that dispersal mechanism138previously moved the liquid phase polyurethane mixture. At this point, flexible blade140may be optionally cleaned by a cleaning mechanism to be prepared for its next application on a subsequent mold.

WhileFIGS. 6-9illustrate discrete events of application of liquid phase polyurethane mixture to a mold120, dispersal of liquid phase polyurethane mixture over a mold120, and the removal of excess liquid phase polyurethane mixture from the flat surface face124of a mold120and forcing liquid polyurethane into a cavity122of mold120, these need not be totally discrete steps or portions of a system in accordance with the present invention. For example, a dispersal mechanism138may be distributing liquid phase polyurethane mixture at one portion of a mold120while a nozzle132is still applying liquid phase polyurethane mixture to a flat surface face124of a mold120. Further, a flexible blade140may be forcing liquid phase polyurethane mixture into a cavity122and removing excess liquid phase polyurethane mixture from a flat surface face124of a mold120while a dispersal mechanism138is still dispersing liquid phase polyurethane mixture across a flat surface face124of a mold120and/or a dispensing mechanism132is still applying liquid phase polyurethane mixture to another portion of a flat surface face124of a mold120.

Referring now toFIG. 10, a method1000for forming cast polyurethane in accordance with the present invention is illustrated. Method1000is merely one example of an acceptable method in accordance with the present invention. Some steps of method1000illustrated in the present example may be omitted, while others may be performed in different orders, and further steps may be added without departing from the scope of the present invention. In step1010, a mold with a flat surface face and a cavity may be prepared for forming cast polyurethane and provided to a dispensing component. The mold provided in step1010may comprise a mold made of aluminum or any other type of material. The mold provided in step1010may be cleaned and/or treated with a mold release material to facilitate the ultimate removal of a cast polyurethane component. Further, the mold provided in step1010may be preheated or cooled, if desired, to provide optimal conditions for forming cast polyurethane from a liquid phase polyurethane mixture.

In step1020a liquid phase polyurethane mixture may be applied to the flat surface face of the mold. Any dispensing mechanism, some examples of which are described herein, may be used in step1020. The amount of liquid phase polyurethane mixture dispensed in step1020may be measured, whether by weight or by volume, to provide a sufficient amount of liquid phase polyurethane mixture to fill a cavity on the mold provided in step1010, and the pattern in which the liquid phase polyurethane mixture is dispensed may correspond to the cavity in the mold.

The liquid phase polyurethane mixture applied to the flat surface face of mold may be distributed in step1030. Step1030may use an air blower, an air knife, vibrational unit, or another dispersal mechanism to spread the liquid phase polyurethane mixture over the flat face of a mold to sufficiently engage a cavity of the mold corresponding to the cast polyurethane part ultimately to be formed by method1000. Optionally, step1030may be eliminated, particularly if prior step1020of applying liquid phase polyurethane mixture applies the liquid phase polyurethane mixture with an adequate distribution over the flat surface face of a mold to appropriately and acceptably fill the cavity of the mold provided in step1010.

A vacuum may be applied to the liquid phase polyurethane mixture on a mold to remove air bubbles from the liquid phase polyurethane mixture in step1040. Step1040may involve creating an appropriately air-tight seal between a vacuum chamber and a mold and/or the surface beneath a mold. The strength of the vacuum applied and the duration of applying the vacuum of step1040may vary based upon the quantity and size of bubbles within the liquid phase polyurethane mixture, the quality desired for the cast polyurethane part, the amount of liquid phase polyurethane mixture dispensed onto the mold, and the viscosity of the liquid phase polyurethane mixture dispensed.

In step1050excess liquid phase polyurethane mixture may be removed from the face of the mold, which may also ensure that liquid phase polyurethane mixture is forced into all areas of a cavity or cavities on a mold. Step1050may be performed using a flexible blade, as described herein. Further, a flexible blade used in performing step1050may be cleaned at various intervals, such as after every use, after every second use, every five minutes of use, etc.

The polyurethane mixture may be further processed and/or cured to change it from a liquid phase to a solid phase within the cavity of the mold in step1060. The curing of step1060may involve the passage of time, the heating of a mold and/or the liquid phase polyurethane mixture within a cavity of a form, manipulating the relative humidity around the polyurethane mixture, etc. to obtain the desired physical properties of the polyurethane for use in a part for a shoe or another item. Any optional post processing performed in step1060may occur before, during, or after any curing of the polyurethane has occurred. For example, a textile may be joined to a partially cured polyurethane part using a heat press to both enable the cast polyurethane to be subsequently removed from the mold more easily and to facilitate the integration of the resulting cast polyurethane part into a larger item, such as a shoe upper.

The various steps of method1000may be performed by different components of a system, while some steps may be combined to be performed in a single step and/or by a single component of a system. A conveyance mechanism may move molds used in practicing method1000from one component or station to another for the performance of various steps of the method1000. More than one conveyance mechanism may be used in such an example, and some steps of method1000may not involve a conveyance mechanism transporting a mold to a particular device, apparatus, or station for performing that step. A mechanism may retain a mold in place for a step of method1000, or a step of method1000may be performed while a mold is in motion through a larger system. A computer system executing instructions retained on computer readable media may control various components may carry out methods in accordance with the present invention such as method1000.

Referring now toFIG. 11, a further example for a flexible blade1140and flexible blade holder1142is illustrated. As shown inFIG. 11, an arm1190may actuate flexible blade1140and holder1142vertically over a distance1195to allow flexible blade1140to engage a surface of a mold1120by containing and moving across the flat surface face1127of mold1120. As explained previously, blade1140when actuated over distance1195may engage mold1120by mold1120being moved towards blade1140, by blade1140being moved towards form1120, or some combination. In the example illustrated inFIG. 11, actuation communicated by arm1190may be accomplished using any type of mechanism or principal. Arm1190may further move flexible blade1140and holder1142horizontally1194across the flat surface face1124of mold1120retained in place by stopper1106. After blade1140has been moved across flat surface face1124of mold1120to remove any excess liquid polyurethane, stopper1106may be withdrawn or released to permit mold1120to be moved further by conveyance mechanism1110.

Referring now toFIG. 12, an example of a vibrational unit1200that may be used to disperse a liquid phase polyurethane mixture1252within a cavity1222of a mold1220. Vibrational unit1200may comprise a base1210or other attachment mechanism that engages a mold1220and shakes or vibrates mold1220as indicated by arrows1290. Any type of engine, motor, or other driving mechanism may be used by vibrational unit1200to impart vibrations to base1210and, ultimately, to mold1220and liquid phase polyurethane mixture1252. The vibrations of a vibrational unit1200may occur in one, two, or three dimensions. A vibrational unit1200may be used in conjunction with another dispersal mechanism or instead of another dispersal mechanism. For example, a vibrational unit1200may be used before, during, or after an air knife or air blower disperses the liquid phase polyurethane mixture1252.

Referring now toFIG. 13, one example of a blade cleaning mechanism1300is illustrated. A blade cleaning mechanism1300may be used to remove excess liquid phase polyurethane mixture from a flexible blade1140after use. Flexible blade1140may resemble that illustrated in the example ofFIG. 11, but other types of flexible blades may be cleaned by a mechanism1300in accordance with the present invention. While various examples of suitable flexible blade cleaning mechanisms have been described above, the example shown inFIG. 13is provided for illustrative purposes. Blade cleaning mechanism1300may be moved relative to the flexible blade1140to be cleaned, although the flexible blade1140may alternatively/additionally be moved towards the cleaning mechanism1300. In the example shown inFIG. 13, a first air nozzle1310dispenses a stream of arrow1312to remove excess liquid phase polyurethane mixture from the flexible blade1140. In the example ofFIG. 13, a second air nozzle1320may provide a second stream of arrow1322to remove excess liquid phase polyurethane mixture from the opposite side of the flexible blade1140from the first air nozzle1310. After the application of air streams from a first air nozzle1310and/or a second air nozzle1320, a first rotating brush1330and/or a second rotating brush1340may engage flexible blade1140while spinning as indicated by arrow1332and arrow1342to remove any remaining liquid phase polyurethane mixture from blade1140that was not removed by air streams1312,1322. The cleaning mechanism1300illustrated inFIG. 13may be actuated towards and away from blade1140mechanically, pneumatically, or through any other process. Further, other examples of blade cleaning mechanisms, some of which are described above, may be used in conjunction with the present invention.

Referring now toFIG. 14, the application of a sheet of material1410using a press1420is illustrated. Sheet1410may comprise, for example, a knit or woven textile, a nonwoven textile, a film material, or any other sheet of material that is desired to be affixed to the cast polyurethane512within cavity122of mold120. Sheet1410may be adhered to polyurethane512using an adhesive and/or the flow properties of the polyurethane512, depending upon the cure status of the polyurethane512. Press1420may comprise a heat press that applies both heat and pressure to facilitate bonding. Affixing sheet1410to polyurethane512may be useful for later construction of a shoe or other item from the cast polyurethane512, as well as to facilitate the extraction of the cast polyurethane512from the cavity122of mold120. The application of a sheet1410using a press1420may particularly occur after polyurethane512has been partially cured, for example using a heating table1210illustrated inFIG. 12.

While a specific example system and method in accordance with the present invention have been described herein, the present invention is not limited to these specific examples. The present invention may be used with any desired formulation of polyurethane and to make any desired part from cast polyurethane. Different materials for forms, flexible blades, and the like may be used, with some materials being better suited to different formulations of polyurethane. Moreover, dispensing mechanisms, dispersal mechanisms, cleaning mechanisms, and the like may vary based upon the particular demands and desires of a specific application of the present invention.