Abstract:
A three-dimensional (3D) printing device has at least one collapsible vertical or horizontal axis using a scissor lift mechanism. One of the horizontal axis&#39;s can be made operable via a track or path where the entire machine moves along that path via movable wheels or gears. Sensors may monitor the height, orientation, position, and relative distance of the axes, machine, or extruders. Compensating mechanisms such as counterweights, propellers, or gyroscopes may be used to maintain balance, levelness, and control of the system. As a result, the size and weight of the 3D printer is reduced and made easier to transport while maintaining quality build functionality.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a three dimensional (3D) printing device. 
       BACKGROUND 
       [0002]    Three dimensional (3D) printing is a form of additive manufacturing also known as stereolithography (“STL”) or Fusion Deposition Method (FDM). Structures, parts, or items may be manufactured by building up successive layers of material which are either fused, adhered, or hardened together. A computer may control the movement and deposition of the desired material, which can be a malleable material such as plastic, through an extruder assembly. Many other materials, for example concrete (concrete like materials), chocolate (food products), rubber, nylon, electrically conductive resins, metals, and epoxy-like (resin hardeners) materials can also be used as well as other materials. 
         [0003]    Typically, the extruder assembly heats the material and extrudes it onto a printing surface or platform. The extruder assembly&#39;s movement may be controlled by a series of actuators, servo-motors, or other movement mechanisms to allow for control in two or more dimensions by a computer. The deposited material layers then cool and harden into the desired shape or form. In some cases the extruder assembly may not require a heating element such as with concrete and the deposited material sets by virtue of other mechanisms such as elapsed time. 
         [0004]    Current 3D printers are constructed with beams or rods that extend the entire height, length, and width (x,y, and z axis) of the printable area. The extruder assembly may be able to travel up and down or side to side along the rods or, alternatively, the build platform or printing surface may be able to travel up or down vertical rods or beams. These configurations allow the desired part to be built by moving the extruder assembly along the vertical and horizontal axis. The limitations of this type of configuration include limited mobility, large size, and weight. It&#39;s also sometimes difficult to adjust and maintain levelness of the extrusion assembly plane through the entire build operation. 
         [0005]    There is a need in the art of three dimensional printers to reduce the amount of space that such printers take up while not in use, and make them more flexible in operation. The present invention is suited to address these needs and more. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is a three dimensional printer that controls a vertical movement of an extruder assembly using scissor lift-type linkages that collapse and expand to several times their contracted height. This allows the 3D printer to be stored or transported in smaller containers, since the printer does not include a frame that encloses the maximum volume of the object to be printed. In the case of a personal 3D printer, it may be designed to fit in a convenient carry-all or suit case, and then when in use expand vertically to print taller objects. In the case of 3D printer used to build large concrete structures such as homes, it may be designed to fit on the back of truck trailer and expand to build multiple storied structures. 
         [0007]    Gyroscopic, optical, or magnetic sensors may be incorporated into the 3D printer along with compensating mechanisms such as counterweights, hydraulics, motor control, or propellers. The levelness or desired orientation of the extruder assembly plane can be monitored and maintained with a computer that corrects such imperfections hundreds of times per second by finely adjusting the height of each vertical scissor lift or other compensation mechanism according to readings from the various sensors. This allows the 3D printer to function properly despite unevenness of the ground or unexpected changes in the environment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an elevated, perspective view of a collapsible 3D printer system in accordance with embodiments of the presented invention. 
           [0009]      FIG. 2  is a side view of the collapsible 3D printer of  FIG. 1 . 
           [0010]      FIG. 3  is an elevated perspective view of a lift mechanism for use in the collapsible 3D printer of  FIG. 1 . 
           [0011]      FIG. 4  is an elevated side perspective view of the lift mechanism of  FIG. 3 . 
           [0012]      FIG. 5  is a side view, partially in phantom, of the collapsible 3D printer of  FIG. 1 . 
           [0013]      FIG. 6  is an enlarged, perspective view of a rotational angle sensor in accordance with embodiments of the presented invention. 
           [0014]      FIG. 7  is an elevated, perspective view of a second embodiment of a collapsible 3D printer. 
           [0015]      FIG. 8  is an elevated, perspective view of a third embodiment of a collapsible 3D printer. 
           [0016]      FIG. 9  is an elevated, perspective view of a fourth embodiment of a collapsible 3D printer. 
           [0017]      FIG. 10  is an elevated, perspective view of a fifth embodiment of a collapsible 3D printer. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]      FIG. 1  shows an embodiment of a collapsible 3D printer  100 . The system includes a base housing  150  containing various mechanical, electrical, and electronic components that operate the printer  100 . An upper housing  155  is positioned above and parallel to the base housing  150  and houses the extruder assembly (not shown) as well as mechanical and electronic components that operate the printer  100 . The upper housing  155  and the lower housing  150  are connected by collapsible scissor linkages  115  that allow the printer  100  to collapse and expand in the vertical direction while remaining parallel to each other. The build material  130  may be kept on spool brackets  170  and fed into the upper housing  155  and through the extruder system. The extruder system is movable along 2 perpendicular horizontal axes and deposits the material  130  onto the build platform  110 . The material  130  is deposited onto the build platform  110  as the linkage  115  moves the upper housing  155  in the vertical direction so that sequential layers of material may be deposited onto the build platform  110 . A system interface  165  is incorporated onto the front of upper housing  155  or lower housing  150  and may include user input devices such as a touchscreen, buttons, keyboard, or any combination thereof. 
         [0019]      FIG. 2  illustrates a 3D printing system  300 A,  300 B, and  300 C as it moves through its various stages of operation.  300 A shows a 3D printing system in its collapsed and transportable position.  300 B shows a 3D printing system roughly halfway through the building of an object  125 . The vertical linkages  115  expand in the vertical direction and moves the upper housing  155  away from the lower housing  150  to allow for the object  125  to be constructed via sequential layers of material that are deposited via the extruder nozzle  175  movable via a stepper motor drive system onto the build platform  110 .  300 C shows a completed build operation in which the vertical linkages  115  may be fully extended and the build object  125  is completed. 
         [0020]      FIGS. 3 and 4  detail the mechanical drive system of the vertical linkages  115  in the illustrated embodiment. Two threaded rods  180  are mounted on opposite sides of a secure metal or plastic frame  200  and are rotatable via a stepper motor  190 . Each threaded rod  180  threads through a drive bracket  185  which has a threaded hole  320  threaded onto rod  180 . A pair of pulleys  225  are configured in such a way that the two rods are rotated precisely the same amount and geared advantageously to the stepper motor  190 . In this embodiment, pulleys  225  are attached to each end of each threaded rod  180  and connected by belts  230 . As the rods  180  are rotated, drive brackets  185  are driven along a linear path and move the bottom legs of the scissor lift linkages  115  closer or father apart from each other thus extending or collapsing the height of the printer  100 . The drive brackets  185  are mounted to housing  200  with a bolt  315  that extends through slotted hole  205  and a linkage  115 . The movement path of linkage  115  is constrained on one leg via a stationary but rotatable mounting bolt  195  and a slotted hole  205  on the other via bolt  315 . 
         [0021]      FIG. 5  is a side view of 3D printer  100  partially in phantom to reveal how scissor lift linkage  115  connects to upper housing  155  and lower housing  150  via stationary bolts  195  and movable bolts  315 . Stationary bolts  195  allow arm of linkage  115  to rotate freely via its mounted position while movable bolts  315  allow the other arm of linkage  115  to move along slotted hole  205 . Lower housing  150  has a motor  190  and threaded rods  180  while upper housing  155  may or may not have threaded rods  180  or motor  190 , although these two housings can be reversed. 
         [0022]      FIG. 6  Shows how the height of the linkage system  115  may be monitored by a rotation sensor (otherwise known as a hall effect sensor)  305  which may determine the angle at which the linkage  115  are positioned by measuring the magnetic field of a magnet  310  that is attached to bolt  195 , and that is fastened to linkage  115 . Most current 3D printer computer systems operate via a Cartesian coordinate system and all of the generated build paths are constructed as such. Since the scissor lift mechanism shown in this embodiment of the invention is non-linear, the rotation angle or polar coordinates of the linkage arms  115  may be converted to linear height through the following equation, y=sqrt(â2−2*x̂2) where a =the length of the linkage arms (all arms are the same length). The proper acceleration rate of motor  190  can then be calculated to move the extrusion assembly the proper linear distance based on its current position. The proper build path may now be constructed and sent to the collapsible 3D printer  100  via computer, USB drive, or other appropriate method. 
         [0023]      FIG. 7  is a perspective view of an alternate embodiment of a collapsible 3D printer that utilizes a drive bar  330  and a single threaded rod  335  to move linkage  115 . The threaded rod  335  is coupled to the drive bar  330  and displaces the drive bar through rotation of the threaded rod. In this manner, the linkages  115  can be opened or closed to extend or contract the printer assembly. 
         [0024]      FIG. 8  is a perspective view of an alternate embodiment of a collapsible 3D printer that makes one axis of the machine movable via parallel tracks  340  and  375 . A scissor lift linkage  115  is mounted to movable cart  345  in the same fashion as previous embodiments but also has wheels, coasters, gliders, or other friction-reducing elements that ride within track  340  on both sides of the build area  355  and are driven by a motor or engine (not shown). One or more movable extruder systems are mounted within housing  350  that extend the width of build area  355  and is connected to the top of each linkage  115  in the same manner as previous embodiments. A concrete mixer  360  may deliver concrete via hose  365  to a movable nozzle (not shown) within housing  350 . The nozzle is able to move the length of housing  350  and deposit un hardened concrete onto build platform  355  as needed by a computer control system. The linkage  115  may move the housing  350  vertically as needed to provide z-axis movement while movable carts  345  may provide movement along length of the build area  355  and build concrete structure  370 . One or more gyroscopic sensors may be incorporated into housing  350 . The levelness or parallel orientation of housing  350  with relation to the build platform  355  can be monitored and maintained with a computer that corrects such imperfections hundreds of times per second by finely adjusting the height of each vertical linkage  115  or other compensation mechanism according to readings from the gyroscopic sensors. Housing  350  is then able to maintain a level orientation despite the possible unevenness of tracks  340  and  375 . Additional magnetic and/or optical sensors may be incorporated into the machine for monitoring the distance between components and/or the build object. 
         [0025]      FIG. 9  is a perspective view on an alternate embodiment of a collapsible 3D printer  410  that includes a carrying handle  400  and a third set of collapsible scissor lift linkages  405 . The third set of linkages  405  provides additional lateral stability to the system during print operations. 
         [0026]      FIG. 10  is a perspective view on an alternate embodiment of a collapsible 3D printer. Two motor driven vertical linkages  435  support two horizontal linkages  420  and a control head  440  with one or more extruders or other attachments designed to place building materials. Two motor driven wenches  425  use cables  435  and pulleys  430  to help support, control, and balance the control head  440 . The control head may have gyroscopic sensor which monitors its position in multiple dimensions. The wenches  425  can either increase or decrease the lift on the control head  440  depending on the readings from sensors. This embodiment of the invention is advantageous because the horizontal axis of the machine can be collapsed or retracted , just like the vertical axis, making the machine smaller and easier to transport. The integrated sensors and compensating mechanisms help the machine to maintain proper alignment with the build surface  355 .