Patent Publication Number: US-2022212364-A1

Title: Apparatus for making and laying bricks

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/133,708, filed on Jan. 4, 2021, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Field of the Art 
     This disclosure relates to an apparatus for making and laying bricks or pavers in a groutless manner. In particular, this disclosure relates to a large-scale nozzle for 3D printing bricks or pavers directly next to each other. Such an automated brick-laying process is particularly advantageous for paving autonomously in otherwise inaccessible locations, such as surfaces on the moon or other planets. 
     Discussion of the State of the Art 
     The process of laying bricks, pavers, or tiles is very labor-intensive work that takes a long time and causes a lot of stress and strain on workers&#39; bodies. Further, these projects require the very heavy bricks, pavers, or tiles to be transported to a job site, which takes a lot of time and energy to haul these large, heavy loads. Bricks, pavers, and tiles typically require grout, cement, or other similar materials to fill the gaps between the bricks, pavers, or tiles. Adding the filler material between the bricks, pavers, or tiles is also very labor- and time-intensive. Another drawback is that the filler material may expand and contract at different rates than the bricks, pavers, or tiles, which may cause cracks or other structural problems. 
     Efforts have been made to automate bricklaying and paving. However, even if the bricklaying and paving can be effectively automated, the bricks or pavers still need to be transported to the job site and fed to the machine. In addition, filler material still has to be deposited between the bricks or pavers. As such, even if part of the bricklaying process can be automated, human intervention is still required. 
     There remains a need for an effective apparatus and method for laying bricks and pavers in an automated way that requires little human intervention. 
     SUMMARY 
     The present invention overcomes these limitations by automating the brick-making and brick-laying processes and by eliminating the need for grout or cement between the bricks. Such automated processes are especially useful for paving surfaces on the moon or other planets but are also useful on Earth for minimizing the time and cost associated with human work hours and for minimizing the impact on the environment associated with transporting large, heavy loads of bricks, pavers, or tiles. 
     Since the bricks are made and deposited at the same time using the apparatus disclosed herein, the need for transporting large, heavy loads of bricks or pavers is eliminated. That is, the bricks can be made from materials available at the job site, such as dirt, dust, clay, and the like, as traditionally done by artisans prior to the mass centralization of brick production. In accordance with the present invention, and in contrast to previous methods, a large-scale 3D printer nozzle deposits bricks or pavers directly adjacent to each other without any other materials, such as grout or concrete, disposed between the bricks or pavers. The material of the bricks or pavers is preferably in a semi-solid, semi-liquid, or molten state so that the bricks or pavers meld together as they cool or cure. These bricks may also be surfaced in a fluxing agent prior to deposition in order to promote brick-to-brick adhesion. 
     In one disclosed embodiment, an apparatus for making and depositing bricks includes a nozzle having an inlet opening, an outlet opening, and a plurality of walls surrounding the outlet opening. At least one of the walls is configured to lift up relative to the other walls. When a first brick is deposited, all of the nozzle walls are in the down position. When subsequent bricks are deposited, one or more of the nozzle walls are lifted. The nozzle walls that are lifted are those that are adjacent to already-deposited bricks. As such, the sides of the already-deposited bricks, along with the nozzle walls that are in the down position, serve as the form for the brick that is being deposited. 
     One embodiment of the present invention is directed to an apparatus for making and depositing bricks. The apparatus includes a nozzle having an inlet opening, an outlet opening, and a conduit extending between the inlet opening and the outlet opening. The outlet opening may have a diameter of approximately 100-200 mm. The conduit may have a longitudinal axis and a plane of the outlet opening may be perpendicular to the longitudinal axis of the conduit. The nozzle is configured so that brick material added to the nozzle through the inlet opening flows through the conduit and exits the nozzle through the outlet opening. 
     The apparatus further includes a plurality of walls surrounding the outlet opening, wherein at least one of the walls is configured to retract relative to the other walls. The apparatus may further include at least one lifting mechanism coupled to the respective at least one wall that is configured to retract. The at least one lifting mechanism may include a linear actuator. The plurality of walls may include at least three walls. The plurality of walls may include six walls, wherein three of the walls may be stationary and three of the walls may be moveable and have a retracted position and an extended position. The apparatus may further include a plurality of vertices between the respective plurality of walls. 
     Another embodiment of the present invention is directed to a method for making and depositing pavers. The method includes using a nozzle to deposit a first brick, wherein the nozzle comprises an inlet opening, an outlet opening, and a plurality of walls surrounding the outlet opening, wherein at least one of the walls is configured to lift up relative to the other walls, and wherein all of the walls are in an extended position during deposition of the first brick. The step of using the nozzle to deposit the first brick may further include adding brick material to the nozzle through the inlet opening; and depositing the brick material out of the nozzle through the outlet opening. 
     The method further includes moving the nozzle to a second location that is adjacent to the first brick and retracting a first wall of the nozzle so that the first nozzle wall is in a retracted position and the other nozzle walls are in the extended position, wherein the retracted first nozzle wall is directly above a first sidewall of the first brick. The nozzle may further include a lifting mechanism coupled to the first nozzle wall, and retracting the first nozzle wall may include activating the lifting mechanism. 
     The method further includes depositing a second brick directly adjacent to the first brick so that a first sidewall of the second brick is in direct contact with the first sidewall of the first brick. The method may further include moving the nozzle to a third location that is adjacent to the first brick and the second brick; retracting the first nozzle wall and a second wall of the nozzle so that the first and second nozzle walls are in the retracted position and the other nozzle walls are in the extended position, wherein the retracted first nozzle wall is directly above a second sidewall of the first brick and the retracted second nozzle wall is directly above a second sidewall of the second brick; and depositing a third brick directly adjacent to the first brick and the second brick so that a first sidewall of the third brick is in direct contact with the second sidewall of the first brick and a second sidewall of the third brick is in direct contact with the second sidewall of the second brick. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The accompanying drawings illustrate several embodiments and, together with the description, serve to explain the principles of the invention according to the embodiments. It will be appreciated by one skilled in the art that the particular arrangements illustrated in the drawings are merely exemplary and are not to be considered as limiting of the scope of the invention or the claims herein in any way. 
         FIG. 1  is a perspective view of a nozzle with moveable walls, in accordance with an embodiment of the present invention. 
         FIGS. 2A-2C  illustrate a process for depositing pavers using the nozzle of  FIG. 1 , in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of a nozzle having moveable walls and springs coupled to the moveable walls, in accordance with an embodiment of the present invention. 
         FIGS. 4A and 4B  are perspective and front views, respectively, of a nozzle having moveable walls and rollers coupled to the moveable walls, in accordance with an embodiment of the present invention. 
         FIGS. 4C and 4D  are cross-sectional views of the nozzle of  FIGS. 4A and 4B  with the nozzle stopper in the down position and the up position, respectively, in accordance with an embodiment of the present invention. 
         FIG. 5A  is a perspective view of a nozzle having moveable walls in accordance with an embodiment of the present invention. 
         FIGS. 5B and 5C  are perspective views of the nozzle of  FIG. 5A  with a flexible bellows removed and with the nozzle walls in extended and retracted positions, respectively. 
         FIG. 5D  is a top view of the nozzle of  FIG. 5A . 
         FIG. 5E  is a bottom view of the nozzle of  FIG. 5A . 
         FIG. 5F  is a perspective view of one of the paddle assemblies from the nozzle of  FIG. 5A . 
         FIGS. 5G and 5H  are front and side views, respectively, of the paddle assembly of  FIG. 5F  with the dust cover and flexible bellows removed and with the nozzle wall in an extended position. 
         FIGS. 5I and 5J  are front and side views, respectively, of the paddle assembly of  FIG. 5F  with the dust cover and flexible bellows removed and with the nozzle wall in a retracted position. 
         FIGS. 5K and 5L  are side cross-sectional views of the paddle assembly of  FIG. 5F  with the dust cover and flexible bellows removed and with the nozzle wall in an extended position and a retracted position, respectively. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is for a nozzle having walls surrounding the outlet of the nozzle, where at least one of the walls is configured to retract relative to the other walls. Such a nozzle can be used in a procedure for making and depositing bricks, pavers, tiles, etc. The lifting wall(s) of the nozzle allow for the bricks, pavers, tiles, etc to be deposited directly adjacent to each other without any intervening materials or space between them. In this manner, the need for grout, cement, or the like to be deposited in the space between the bricks is eliminated. The material used to form the bricks is preferably in a semi-solid, semi-liquid, and/or semi-molten state so that bricks that are adjacent to each other meld together as the material cools, solidifies, and/or cures. Further, human intervention is minimized in the automated process for laying bricks using the nozzle of the present invention. Another advantage of the nozzle of the present invention is that the bricks or pavers are made on-site, and the materials for making the bricks or pavers may be obtained directly from the job site, thereby eliminating the need to transport the bricks or pavers to the job site. 
     The nozzle of the present invention can be used for depositing bricks, pavers, tiles, or any other similar blocks used for paving a surface. The terms “bricks,” “pavers,” “tiles,” and “blocks” are used interchangeably herein to refer to any material that may be used for paving a surface. 
     The invention is described by reference to various elements herein. It should be noted, however, that although the various elements of the inventive apparatus are described separately below, the elements need not necessarily be separate. The various embodiments may be interconnected and may be cut out of a singular block or mold. The variety of different ways of forming an inventive apparatus, in accordance with the disclosure herein, may be varied without departing from the scope of the invention. 
     Generally, one or more different embodiments may be described in the present application. Further, for one or more of the embodiments described herein, numerous alternative arrangements may be described; it should be appreciated that these are presented for illustrative purposes only and are not limiting of the embodiments contained herein or the claims presented herein in any way. One or more of the arrangements may be widely applicable to numerous embodiments, as may be readily apparent from the disclosure. In general, arrangements are described in sufficient detail to enable those skilled in the art to practice one or more of the embodiments, and it should be appreciated that other arrangements may be utilized and that structural changes may be made without departing from the scope of the embodiments. Particular features of one or more of the embodiments described herein may be described with reference to one or more particular embodiments or figures that form a part of the present disclosure, and in which are shown, by way of illustration, specific arrangements of one or more of the aspects. It should be appreciated, however, that such features are not limited to usage in the one or more particular embodiments or figures with reference to which they are described. The present disclosure is neither a literal description of all arrangements of one or more of the embodiments nor a listing of features of one or more of the embodiments that must be present in all arrangements. 
     Headings of sections provided in this patent application and the title of this patent application are for convenience only and are not to be taken as limiting the disclosure in any way. 
     Devices and parts that are connected to each other need not be in continuous connection with each other, unless expressly specified otherwise. In addition, devices and parts that are connected with each other may be connected directly or indirectly through one or more connection means or intermediaries. 
     A description of an aspect with several components in connection with each other does not imply that all such components are required. To the contrary, a variety of optional components may be described to illustrate a wide variety of possible embodiments and in order to more fully illustrate one or more embodiments. Similarly, although process steps, method steps, or the like may be described in a sequential order, such processes and methods may generally be configured to work in alternate orders, unless specifically stated to the contrary. In other words, any sequence or order of steps that may be described in this patent application does not, in and of itself, indicate a requirement that the steps be performed in that order. The steps of described processes may be performed in any order practical. Further, some steps may be performed simultaneously despite being described or implied as occurring non-simultaneously (e.g., because one step is described after the other step). Moreover, the illustration of a process by its depiction in a drawing does not imply that the illustrated process is exclusive of other variations and modifications thereto, does not imply that the illustrated process or any of its steps are necessary to one or more of the embodiments, and does not imply that the illustrated process is preferred. Also, steps are generally described once per aspect, but this does not mean they must occur once, or that they may only occur once each time a process, or method is carried out or executed. Some steps may be omitted in some embodiments or some occurrences, or some steps may be executed more than once in a given aspect or occurrence. 
     When a single device or article is described herein, it will be readily apparent that more than one device or article may be used in place of a single device or article. Similarly, where more than one device or article is described herein, it will be readily apparent that a single device or article may be used in place of the more than one device or article. 
     The functionality or the features of a device may be alternatively embodied by one or more other devices that are not explicitly described as having such functionality or features. Thus, other embodiments need not include the device itself. 
     Techniques and mechanisms described or referenced herein will sometimes be described in singular form for clarity. However, it should be appreciated that particular embodiments may include multiple iterations of a technique or multiple instantiations of a mechanism unless noted otherwise. Alternate implementations are included within the scope of various embodiments in which, for example, functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those having ordinary skill in the art. 
     Overview 
     The apparatus of the present invention is a large nozzle for 3D printing bricks or pavers. The nozzle has an inlet opening, an outlet opening, and a plurality of walls surrounding the outlet opening. Material for forming the bricks is added to the nozzle through the inlet and the material is deposited in the form of a brick through the outlet. One or more of the walls is configured to move up and down relative to the other walls. In this manner, the nozzle is configured to deposit bricks or pavers directly adjacent to each other with no space or intervening materials therebetween. When a brick or paver is deposited adjacent to one or more other bricks or pavers, the wall(s) of the nozzle that are adjacent to the already-deposited bricks or pavers moves up relative to the other walls. Thus, the already-deposited bricks or pavers are part of the form for subsequently deposited bricks or pavers. The bricks or pavers are deposited in a semi-liquid or semi-solid state so that the bricks or pavers meld together as they cure, cool, and/or solidify. These bricks may also be surfaced in a fluxing agent prior to deposition in order to promote brick-to-brick adhesion. 
     Apparatus 
       FIG. 1  illustrates one example of a nozzle  100  in accordance with an embodiment of the invention. In particular,  FIG. 1  illustrates a large-scale nozzle  100  for making and depositing pavers. The nozzle  100  may be attached to a heater, material supply source, sensors, processors, pumps, controllers and/or the like, so that a material to be used for making bricks or pavers is deposited through the nozzle  100  in an automated way. The bricks or pavers are deposited in a liquid or semi-liquid form that solidifies as it cools. 
     The nozzle  100  includes an outlet opening  102  that is the desired shape of the bricks or pavers. The diameter of the opening  102  may be any desired diameter. For example, the diameter of the opening  102  may be between 50 mm and 300 mm, between 100 mm and 200 mm, or the like. The opening  102  lies in a plane that is perpendicular to a longitudinal axis  106  of the nozzle  100 . 
     The nozzle  100  includes a plurality of walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  surrounding the opening  102 . Some, if not all, of the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  are configured to move up and down relative to each other.  FIG. 1  depicts the nozzle  100  with all of the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  in the down, or extended, position. One or more of the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  may also have an up, or retracted, position. In other words, each one of the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  may be able to retract relative to the other walls. Some of the walls may be stationary and only the remaining walls may be configured to move up and down relative to the stationary walls. For example, only one, two, or three of the walls may be configured to move up relative to the stationary walls, depending on the shape of the opening  102 . 
     In the embodiment shown in  FIG. 1 , each wall  104  has a curved shape. Some of the walls  104   a ,  104   c ,  104   e  have a convex shape, while the remaining walls  104   b ,  104   d ,  104   f  have a concave shape. It should be well understood by one of ordinary skill in the art that the walls may have any desired shape. For example, rather than being curved, the walls may be straight, thereby defining a polygonal shaped outlet opening. In addition, it should be well understood by one of ordinary skill in the art that there may be any desired number of walls. While the example shown in  FIG. 1  includes six walls, the nozzle  100  may alternatively have 3, 4, 5, 7, 8, or more walls. Depending on the number of walls and the shape of the walls, the opening  102  may be in the shape of a lobed hexagon (as shown in  FIG. 1 ), triangle, square, rectangle, hexagon, pentagon, octagon, or any other desired shape. 
     In the embodiment shown in  FIG. 1 , the nozzle  100  includes vertices  105   a ,  105   b ,  105   c ,  105   d ,  105   e ,  105   f  at the points where the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  come into contact with each other. The opening  102  may be any desired shape, but is preferably a shape that includes vertices so that the bricks can be deposited directly adjacent to each other with no space in between. 
     The nozzle  100  further includes an inlet opening  108  and a conduit  110  extending through the nozzle  100  in communication with the inlet opening  108  and the outlet opening  102 . The conduit  110  has a longitudinal axis  106 . The outlet opening  102  is in a plane that is perpendicular to the longitudinal axis  106 . Brick material added to the nozzle  100  through the inlet opening  108  flows through the conduit  110  and out of the outlet opening  102  in order to deposit a brick in a desired location. 
       FIG. 2A  depicts a first brick  202  and the nozzle  100  in the process of depositing a second brick directly adjacent to the first brick  202 . When the first brick  202  is deposited, all of the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  of the nozzle  100  are in the extended position. That is, the walls  104   a ,  104   b ,  104   c ,  104   d ,  104   e ,  104   f  surrounding the outlet opening  102  serve as the form for the first brick  202 . Material added to the nozzle  100  through the inlet opening  108  passes through conduit  110  in the nozzle  100  and is deposited through the outlet opening  102  onto a surface. The deposited material is a brick (e.g., first brick  202 ) in the shape of the outlet opening  102 . As depicted in  FIG. 2A , when the next brick is deposited directly adjacent to the first brick  202 , one of the walls  104   b  is in the up position. The wall  104   b  is lifted relative to the other walls  104   a ,  104   c ,  104   d ,  104   e ,  104   f  so that the form of the brick being deposited is provided by the remaining walls  104   a ,  104   c ,  104   d ,  104   e ,  104   f , and one of the sides of the first brick  202 . The nozzle walls  104   a  and  104   c  on either side of the lifted wall  104   b  are in direct contact with the brick  202  so that the material being deposited does not leak out of a space between the nozzle walls and the brick sidewall. The bottom surface of the lifted wall  104   b  is directly above the sidewall of the brick  202  and may rest on top of the sidewall of the brick  202 . 
       FIG. 2B  depicts the first brick  202 , a second brick  204 , and the nozzle  100  in the process of depositing a third brick directly adjacent to the first brick  202  and the second brick  204 . Two of the nozzle walls,  104   b  and  104   c , are lifted when the third brick is extruded from the nozzle  100 . Thus, the form of the third brick is provided by the remaining nozzle walls  104   a ,  104   d ,  104   e ,  104   f , and one of the sides of each of the already-deposited bricks  202 ,  204 . Again, the nozzle walls  104   a  and  104   d  on either side of the lifted nozzle walls  104   b ,  104   c  are in tight, direct contact with the bricks  204  and  202 , respectively so that material being deposited during the process of forming the third brick does not leak out of a space between the nozzle walls  104   a ,  104   d  and the brick sidewalls. The bottom surfaces of the lifted walls  104   b  and  104   c  may rest, respectively, on the bricks  204  and  202 . 
       FIG. 2C  depicts the first brick  202 , second brick  204 , third brick  206  (i.e., the “already-deposited” bricks), and the nozzle  100  in the process of depositing a fourth brick. When the fourth brick is being deposited, two of the nozzle walls,  104   b  and  104   c , are lifted since they are adjacent to already-deposited bricks  206  and  204 . In one embodiment, the bottom surfaces of the lifted walls  104   b  and  104   c  may rest on top of the respective bricks  206  and  204 . The form for the fourth brick is provided by the remaining nozzle walls  104   a ,  104   d ,  104   e ,  104   f , and one of the sides of each of the bricks  204 ,  206 . During deposition of the fourth brick, the nozzle walls  104   a  and  104   d  that are on either side of the lifted walls  104   b  and  104   c  are in tight, direct contact with the already-deposited bricks  206  and  204 , respectively, to prevent material from leaking out of a space between the bricks  204 ,  206  and the nozzle walls  104   a ,  104   d . In this manner, the bricks are deposited directly adjacent to each other without any intervening layers or materials in between the bricks. 
     The bricks are deposited in a liquid, semi-liquid, semi-melted, or heated state so that, as the bricks cool, they will meld together and solidify. The bricks may also be surfaced in a fluxing agent prior to deposition in order to promote brick-to-brick adhesion. 
     The nozzle  100  may be attached to a machine or robot that moves the nozzle  100  in the x, y, and z directions. The machine may be programmed to automatically move the nozzle  100  into position for depositing bricks. After a brick is deposited, the machine may be programmed to move the nozzle up in the z direction and to move the nozzle in the x and y directions to a position directly adjacent to one side of the already-deposited brick. Once the nozzle is in the correct position, the nozzle wall that is adjacent to the one side of the already-deposited brick is lifted and the nozzle is moved down in the z direction. 
     The nozzle  100  may also be coupled to a sensor and a processor configured to determine which wall(s) of the nozzle  100  should be in the retracted position. In other words, the sensor is configured to determine the position of adjacent bricks and, based on those positions, the processor determines which one(s) of the moveable walls need to be in the lifted position during brick deposition. 
     The processor may be coupled to a controller configured for moving the nozzle walls up and down. The controller may be coupled to a mechanism for lifting the walls of the nozzle  100 . The lifting mechanism may be coupled to the moveable walls and may include any type of linear actuator, such as springs, rollers, hydraulics, pneumatics, or the like. Alternatively, the walls of the nozzle  100  may be lifted manually during brick deposition. That is, the walls of the nozzle  100  that are adjacent to already-deposited bricks may be pushed up by resting on top of the already-deposited bricks while the rest of the nozzle is moved downward relative to the already-deposited bricks. 
     In one embodiment, shown in  FIG. 3 , a nozzle  300  with moveable walls  304  includes springs  306  (third spring not shown) coupled to the walls  304 . The springs  306  are biased to be in the extended configuration shown in  FIG. 3 . The load required to compress the springs  306  is relatively small. When one of the moveable walls  304  comes into contact with an already-deposited brick, the pressure between the brick and the moveable wall  304  is sufficient to compress the spring  306 , thereby allowing the wall  304  to move upwards relative to the other walls of the nozzle. 
     In another embodiment, the nozzle  300  may include a controller coupled to the springs  306 . A processor and controller coupled to the springs  306  causes one or more of the springs  306  to compress, thereby lifting the wall(s)  304  associated with the compressed springs. 
     In another embodiment, shown in  FIGS. 4A-4D , a nozzle  400  with moveable walls  404  includes rollers  406  coupled to the walls  404 . Although the three sets of rollers  406  are depicted in  FIGS. 4A and 4B , only two of the moveable walls  404  are visible in  FIGS. 4A and 4B . After placing a brick, the nozzle  400  moves to another location adjacent to the deposited brick. In the adjacent location, the bottom lip, or bottom surface of one of the moveable walls  404  rests on, or directly above, the already-deposited brick. When the nozzle  400  is moved in the downward direction, the rollers  406  associated with the moveable wall  404  resting on the already-deposited brick move upward to retract the moveable wall  404 . 
     In another embodiment, the rollers  406  may be coupled to a controller. When a processor determines that one or more of the walls  404  are required to be in the up position during deposition, the controller causes the rollers  406  to raise the appropriate walls. 
     Referring now to  FIGS. 4C and 4D , the material for forming the pavers is a molten material  410  that is held in a crucible, or conduit,  412  and heated by an induction coil or similar heating apparatus  414  that surrounds the crucible  412 . The crucible  412  includes a crucible cap  416  and an opening  418  through which additional paver material can be added to the crucible  412 . A stopper rod  420  extends through the center of the crucible  412  and functions to plug the outlet  422  and prevent molten material  410  from exiting the crucible  412 , as shown in  FIG. 4C . The stopper rod  420  is coupled to lift motors  408  and rollers  409 . The lift motors  408  are activated to move the rollers  409  upwards or downwards, thereby causing the stopper rod  420  to raise or lower, respectively. When the stopper rod  420  is lifted, as shown in  FIG. 4D , the molten material  410  is allowed to exit the crucible  412  and form a paver  424 . 
     In another embodiment, shown in  FIGS. 5A-5L , a nozzle  500  with moveable walls  504  includes a retraction mechanism  506  coupled to each wall  504 . However, it should be well understood by one of ordinary skill in the art that one or more of the walls  504  may be stationary and thus not include a retraction mechanism  506 . Each retraction mechanism  506  includes an upper portion having a dust cover  508  and a lower portion having a flexible bellows  510  for protecting the lower portion of the retraction mechanism  506  from dust and/or the elements. 
       FIGS. 5B and 5C  illustrate the nozzle  500  with the flexible bellows  510  removed.  FIG. 5B  illustrates the nozzle  500  with all of the walls  504  in an extended position, and  FIG. 5C  illustrates the nozzle  500  with all of the walls  504  in a retracted position after depositing a brick  520 . The retraction mechanism illustrated in  FIGS. 5A-5L  is configured to retract the walls  504  vertically and radially. That is, as the walls  504  are retracted, the walls  504  move upwards relative to the deposited bricks  520  and slightly radially outward relative to the deposited bricks  520 . Due to the radial direction of the retraction, as shown in  FIG. 5C , when the walls  504  are in the retracted position, there is a small space  512  between each wall. It has been found that the radial direction of the retraction may be advantageous if the material being deposited is particularly abrasive. In order to avoid too much friction and wear on the walls  504 , it may be desirable to retract the walls  504  in a radial direction as well as a vertical direction. It should be well understood that the radial direction of the retraction is optional and that the walls  504  may alternatively be retracted vertically only. 
     The nozzle  500  illustrated in  FIGS. 5A-5E  includes six paddle assemblies. It should be well understood by one of ordinary skill in the art that the nozzle  500  may include any number of paddle assemblies, depending on the desired shape of the nozzle outlet. For example, the nozzle  500  may include 3, 4, 5, 7, 8, or more paddle assemblies. 
       FIG. 5F  depicts a single paddle assembly  530 .  FIGS. 5G-5L  illustrate the paddle assembly  530  with the dust cover  508  and the flexible bellows  510  removed. Thus, the retraction mechanism  506  is shown in more detail in  FIGS. 5G-5L . 
     The retraction mechanism  506  includes a drive screw  542  coupled to a motor  544  configured to rotate the drive screw  542 . The drive screw  542  rotates in a first direction for retracting the wall  504  and in an opposite, second direction for extending the wall  504 . The retraction mechanism  506  is not limited to a drive screw  542  for the linear actuator. It will be well understood that any other type of linear actuator may be used in the retraction mechanism. For example, the linear actuator may be mechanical, electro-mechanical, hydraulic, pneumatic, etc. 
     The drive screw  542  is also coupled to the wall  504  through a linkage comprising four bars  546   a ,  546   b ,  546   c ,  546   d  and a connector bar  548 . The connector bar  548  is coupled to a threaded drive nut  550  that moves linearly up and and down the drive screw  542  as the drive screw  542  rotates. The lifting mechanism  506  further includes a slider  552 , shown in  FIG. 5G . The slider  552  and the four bars  546  are coupled to tracks on either side of the paddle assembly  530 . As such, the slider  552  and the four bars  546  maintain their alignment with each other by riding in the tracks during the up and down movement of the wall  504 . 
     The configuration of the four bars  546  and the tracks can be seen more clearly in  FIGS. 5K and 5L . The four bars  546  are hingedly attached to each other in a parallelogram shape when the wall  504  is in the extended position, as shown in  FIG. 5K . Bars  546   b  and  546   d  are vertical and parallel to each other. Bars  546   a  and  546   c  are angled relative to the vertical bars  546   b ,  546   d  and are parallel to each other. When the wall  504  is in a retracted configuration, as shown in  FIG. 5L , the four bars  546  rotate around the hinges until they are aligned with each other. 
       FIG. 5L  also depicts the distal end of one of tracks  558  to which the bars  546  and the slider  552  are attached. The distal end of the track  558  is curved relative to the rest of the track  558 , which is vertical. Due to the curvature at the distal end of the track  558 , the wall  504  moves both radially and vertically. In another embodiment, the track  558  may be straight, thereby eliminating the radial movement of the wall  504 . That is, rather than having a curved distal end, the track  558  may be completely vertical, which will cause the wall  504  to move straight up and down. 
       FIGS. 3-5L  are exemplary embodiments of lifting mechanisms for lifting the moveable walls of the nozzle. It will be readily apparent to one of ordinary skill in the art that other lifting mechanisms are within the scope of this invention. For example, the moveable walls of the nozzle may be lifted and lowered along a variety of fixed or adaptive pathways using a set of linkages actuated by hydraulics, pneumatics, motors, spring tension, or the like. 
     Additional Considerations 
     As used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
     Some embodiments may be described using the expression “coupled” and “connected” along with their derivatives. For example, some embodiments may be described using the term “coupled” to indicate that two or more elements are in direct physical or electrical contact. The term “coupled,” however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments are not limited in this context. 
     As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and Bis false (or not present), A is false (or not present) and Bis true (or present), and both A and B are true (or present). 
     In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. 
     Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs for a system and a process for creating an interactive message through the disclosed principles herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various apparent modifications, changes and variations may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.