Abstract:
A block is made from loose earth. A press foot in a breech is raised to a first level even with the top of the breech. The press foot is lowered to a second level to receive a volume of loose earth from a feed drawer. The feed drawer is withdrawn to screed excess loose earth from the top of the breech. A bucking foot is lowered to close the breech. The press foot is raised to a third level to compress the loose earth into a block. The bucking foot is raised to permit vertical ejection of the block into the path of the feed drawer. Upon again raising the press foot to the first level, a previously-made block is simultaneously raised. Upon again moving the feed drawer over the breech, the previously-made block is simultaneously pushed aside.

Description:
This application is a continuation of application Ser. No. 09/275,172, filed Mar. 24, 1999 U.S. Pat. No. 6,302,675. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to machines for the manufacture of building block and more particularly concerns a machine and a method for making blocks of pressed earth. 
     In my earlier U.S. Pat. No. 5,629,033, a pressed earth block machine suitable for the manufacture of flat-surfaced blocks was disclosed. However, the invention disclosed therein is not suitable for the manufacture of blocks having three-dimensional surfaces in the orthogonally oriented sides of the blocks. In some building applications, it is desirable that the blocks have a tongue and groove configuration in both their lateral sides for maximum strength between laterally adjacent blocks and in their upper and lower surfaces for maximum strength between vertically adjacent blocks. A three dimensional configuration in orthogonal faces presents new problems in the pressing of the block in the breech, the ejection of the block from the breech and the transfer of the ejected block out of the path of the breech without causing damage to the block or its three dimensional contours. These problems are in addition to the normal requirements in speed of manufacture of the blocks, consistency of size and density of the blocks and simplicity of operation and maintenance of the machine. 
     It is, therefore, an object of this invention to provide a machine and method for manufacturing pressed earth blocks which make pressed earth blocks of constant density and depth. Another object of this invention is to provide a machine and method for manufacturing pressed earth blocks which facilitate the rapid production of uniform earth blocks. Yet another object of this invention is to provide a machine and method for manufacturing pressed earth blocks which produce blocks which are tongued-and-grooved in block surfaces that are orthogonal to each other. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, a method is provided for making a block from pressed earth. A press foot is raised in a breech to a first level even with an open upper end of the breech. A feed drawer having an open lower end and filled with granular material or loose earth is moved laterally across a planar surface into registration over the breech. The press foot is then lowered to a second level in the breech to receive a volume of the loose earth from the feed drawer into the breech. The feed drawer is withdrawn laterally across the planar surface out of registration with the breech to remove or screed the excess loose earth from above the open upper end of the breech. A bucking foot is then lowered to close the upper end of the breech. The press foot is raised to a third level in the closed breech to compress the loose earth in the breech into a block. The bucking foot is then raised to a level higher than the top of the feed drawer to permit vertical ejection of the block from the open upper end of the breech into the lateral path of the feed drawer. Upon repetition of the first step of raising the press foot to the first level, a previously-made block will be simultaneously raised into the lateral path of the feed drawer. Upon repetition of the second step of moving the feed drawer laterally into registration over the breech, the previously-made block will be simultaneously pushed out of the path of the bucking foot. Preferably, when the feed drawer is fully withdrawn laterally across the planar surface out of registration with the breech, the feed drawer will be aligned under a hopper storing loose earth and additional loose earth will be dispensed from the hopper to refill the feed drawer. 
     In making vertically and laterally tongue-and-grooved blocks, the press foot and the bucking foot have complementary three dimensional upper and lower surfaces, respectively, and the breech has complementary three dimensional opposite side surfaces. Preferably, the step of moving the feed drawer and simultaneously pushing the previously-made block is performed by abutment of a three dimensional face of the previously-made block with a leading face of the feed drawer. 
     The machine for making block has an orthogonal breech aligned on a Z-axis and open upper and lower ends. The press foot is aligned below the breech for vertical reciprocal movement along the Z-axis within the breech. The feed drawer is aligned laterally of the breech for horizontal reciprocal movement along a Y-axis and has an open lower end for dispensing loose earth into the breech. The bucking foot is aligned above the breech for vertical reciprocal movement along the Z-axis to open and close the upper end of the breech. A hydraulic cylinder moves the feed drawer across a surface coplanar with the feed drawer open lower end into and out of registration with the breech. A second hydraulic cylinder moves the bucking foot into and out of abutment with the open upper end of the breech. A third hydraulic cylinder raises the press foot to a first level even with the open upper end of the breech when the feed drawer is out of registration with the breech, lowers the press foot to a second level in the breech to receive a volume of loose earth when the feed drawer is in registration with the breech and raises the press foot to a third level within the breech when the bucking foot is in abutment with the upper end of the breech to compress the loose earth in the breech against the bucking foot and form a block of pressed earth. 
     Preferably, the breech is substantially rectangular in the X-Y plane with two-dimensional surfaces in its Y-Z side walls and complementary three-dimensional surfaces in its X-Z side walls to provide the lateral tongue-and-groove of the block. All preferably, the press foot and the bucking foot have complementary three-dimensional surfaces in their upper and lower X-Y walls, respectively, to provide the vertical tongue-and-groove of the block. 
     Preferably, the machine further includes a hopper storing loose earth and aligned above the feed drawer when the feed drawer is out of registration with the breech. An open upper end of the feed drawer admits loose earth into the feed drawer from the hopper. The feed drawer has a trailing plate coplanar with its open upper end for closing the hopper when the feed drawer is in registration with the breech. 
     It is specially preferred that the feed drawer has a fixed wall with a lower edge notched to pass over the three dimensional surface of the press foot and push an already made block out of registration with the breech during forward motion of the feed drawer and a hinged wall following the fixed wall with a level lower edge for screeding along the open upper end of the breech during rearward motion of the feed drawer and for swinging clear above the three dimensional surface of the press foot during forward motion of the feed drawer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following details description and upon reference to the drawings in which: 
     FIGS. 1 through 8 are side elevation general arrangement drawings illustrating a preferred embodiment of the pressed earth block machine and the sequential steps of the method of making pressed earth blocks; and 
     FIG. 9 is an isometric view of a preferred embodiment of a pressed earth block made in accordance with the machine and process of FIGS. 1 through 8; 
     FIG. 10 is a top plan view of the block of FIG. 9; 
     FIG. 11 is an end elevation view of the block of FIG. 9; 
     FIG. 12 is a side elevation view of a preferred embodiment of the feed drawer of the pressed earth block machine; 
     FIG. 13 is a front elevation view of the feed drawer of FIG. 12; and 
     FIG. 14 is a schematic drawing of a preferred embodiment of the hydraulic system of the pressed earth block machine. 
    
    
     While the invention will be described in connection with a preferred embodiment and method, it will be understood that it is not intended to limit the invention to that embodiment and method. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     Turning first to FIGS. 1 through 8, the general arrangement of the pressed earth block machine and the method by which the blocks are made is illustrated. The major components of the machine are a breech  10  which defines the side walls of the block, a press foot  20  which defines the bottom surface of the block, a feed drawer  30  which delivers earth to the breech  10  and screeds the surface surrounding the breech on withdrawal, a bucking foot  50  which defines the upper face of the block, a hopper  60  which supplies earth to the feed drawer  30  and an hydraulic system  70  which drives the press foot  20 , the feed drawer  30  and the bucking foot  50 . 
     The breech  10  is aligned on a Z-axis  11  and is substantially rectangular in the X-Y plane. The breech  10  is open at its upper and lower ends and a planar surface  18  extends outwardly from the upper perimeter of the breech  10 . The press foot  20  is reciprocally driven by an hydraulic cylinder  21  having its shaft  22  extending upwardly to the bottom of the press foot  20 . The press foot  20  moves along the Z-axis  11  within the breech  10 . The feed drawer  30  has a front end  31  and an open bottom  32 . A plate  33  coplanar with the top of the drawer  30  extends rearwardly from the drawer  30 . The drawer is reciprocally driven along the Y-axis  15  by a second hydraulic cylinder  34  having its shaft  35  connected to the rear of the feed drawer  30 . The drawer  30  also has an open upper end  36 . The bucking foot  50  is reciprocally driven along the Z-axis  11  by a third hydraulic cylinder  51  having its shaft  52  connected to the top of the bucking foot  50 . The hopper  60  is mounted above the feed drawer  30  when the feed drawer is in its fully withdrawn position. The hopper  60  has an open bottom  61  and receives loose earth through an open top  62 . 
     The operation of the machine is sequentially illustrated in FIGS. 1 through 8. Looking at FIG. 1, the press foot  20  is fully upwardly extended to a first level  23  which is coplanar with the planar surface  18  at the upper end of the breech  10 . The feed drawer  30  is fully withdrawn into registration beneath the hopper  60  and the bucking foot  50  is fully raised to clear the path of lateral motion of the feed drawer  30 . Assuming that no previous cycles of the machine have occurred, the block B shown by dotted lines in FIG. 1 is not present at the beginning of the first cycle of operation. Looking at FIG. 2, the feed drawer  30  has been fully extended out of registration with the hopper  60  and into registration with the breech  10 . In this position, the open bottom  61  of the hopper  60  is closed by the trailing plate  33  on the feed drawer  30  and the open bottom  32  of the feed drawer  30  is closed by the planar surface  18  and the top of the press foot  20 . Turning to FIG. 3, the press foot  20  is lowered to a second level  24  and loose earth M is dispensed from the drawer  30  into the breech  10 . As shown in FIG. 4, the feed drawer  30  is then fully withdrawn from registration with the breech  10  and into registration with the hopper  60 . The front end  31  of the feed drawer  30  screeds the excess loose earth M as it returns to its registration under the hopper  60 . Looking at FIG. 5, once the feed drawer  30  is fully withdrawn, the path of the bucking foot  50  is clear and the bucking foot  50  is fully lowered onto the breech  10 , closing the upper end of the breech  10 . As shown in FIG. 6, the press foot  20  is then raised to a third level  25  above the second level  24  and compresses the loose earth M into a block B. The third level  25  is determined by preselection of the pressure to be exerted between the press foot  20  and the bucking foot  50  which will in turn be determined in relation to the desired density of the block B. After the block is formed, as shown in FIG. 7, the bucking foot  50  is fully withdrawn to its home position clearing the path of the feed drawer  30 . Then, as shown in FIG. 8, the press foot  20  is returned to its first level  23  to position the block B in the path of the feed drawer  30 . Going back to FIG. 1, during the next cycle of the machine, when the feed drawer  30  is moved into registration with the breech  10 , the front end  31  of the feed drawer  30  will push the block B out of registration with the breech  10  to clear the breech  10  for the subsequent cycle. The block B can then be collected for delivery to its next destination. 
     Turning now to FIGS. 9 through 11, the configuration of the breech  10 , the upper face of the press foot  20  and the lower face of the bucking foot  50  can be understood. It is, in many applications, desirable that the block B have a tongue-and-groove configuration both laterally and vertically to add strength to the assembled structure of blocks. Preferably, the lateral tongue-and-groove will be tapered to facilitate stacking of the blocks. To accomplish this, the breech  10  will have two dimensional surfaces  12  and  13  in its opposed Y-Z planes and will have complementary three dimensional surfaces  16  and  17  in its opposed X-Z planes. Thus, the X-Y cross-section of the breech  10  will define the lateral tongue-and-groove configuration of the block B. To provide the vertical tongue and groove configuration, the upper face of the press foot  20  and the lower face of the bucking foot  50  are complementary three-dimensional surfaces  26  and  43 , respectively. As shown, it is preferred that the outer corners of the block B are beveled at approximately 45 degrees. To accomplish this, the upper face of the press foot  20  and the lower face of the bucking foot  50  are also contoured to provide this bevel. It is further desirable that the vertical tongue-and-groove of the block B be tapered at an angle of approximately 15 degrees-off-90 to facilitate engagement of sequential blocks and the upper surface of the press foot  20  and the lower surface of the bucking foot  50  are contoured for this purpose as well. 
     In making blocks B of a contoured lower face, the lower level of the three-dimensional surface will be parallel to the planar surface  18  as shown in FIGS. 1 through 8, so that the three-dimensional contour of the press foot  20  will extend above the planar surface  18  and the top of the breech  10 . Thus, in order to facilitate the pushing of the block B off the press foot  20  by the front end  31  of the feed drawer  30  while also permitting the front end  31  of the feed drawer  30  to screed the planar surface  18  upon withdrawal of the feed drawer  30 , the front end  31  of the feed drawer must be specially adapted. As shown in FIGS. 12 and 13, a push plate  39  is fixed to the forward ends of the side walls  37  and  38  of the feed drawer  30 . As can best be seen in FIG. 13, the bottom edge of the push plate  39  is provided with notches  44 ,  45  and  46  as required to pass over and clear the three-dimensional surface of the press foot  20 . A hinge plate  41  connected by a hinge  42  to a baffle  43  extending across the top forward portion of the feed drawer  30  is disposed in its normal condition with the hinge plate  41  in vertical alignment and following behind the push plate  39 . The bottom edge of the hinge plate  41  is not notched. As the feed drawer  30  moves into registration over the breech  10 , the lower edge of the hinge plate  41  strikes the three-dimensional portions of the upper face of the press foot  20  and the hinge  42 . The hinge plate  41  rotates rearwardly so that the lower edge of the plate  41  will ride on the uppermost portion of the press foot  20 . When the feed drawer  30  is withdrawn to registration with the hopper  60 , the rearward motion of the feed drawer  30  together with the excess material already in the feed drawer  30  causes the hinge plate  41  to return to its normal vertical position to screed along the planar surface  18  during withdrawal. As shown, a section of round stock  47  may be secured at the bottom edge of the hinge plate  41  to facilitate the hinging motion of the plate  41  as it strikes the upper surface of the press foot  20 . In addition, a wiper  48 , preferably of nylon, is mounted across the lower inner surface of the hinge plate  41  for maximum screeding efficiency. 
     Turning now to FIG. 14, illustrating the hydraulic system  70  of the machine, the operation of the machine can be understood in greater detail. A two-stage pump  71  delivers hydraulic fluid from a reservoir  72  through a supply line  73  to a first four-way three-position lever operated valve  74  serving the bucking foot  50 . The first lever operated valve  74  is series connected by a line  75  to a second four-way, three-position, lever operated valve  76  serving the press foot  20  and feed drawer  30  of the machine. From the second lever operated valve  76 , fluid travels through a return line  77  and a filter  78  to the reservoir  72 . With the lever operated valves  74  and  76  in their normal condition as shown, the pump  71  merely circulates fluid to the reservoir  72  and the other components of the hydraulic system  70  are idle. In this condition, when the operator pushes the lever  79  of the second lever operated valve  76 , fluid is delivered through a sequence valve  81  and a check valve  82  to the press foot cylinder  21 , driving the cylinder shaft  22  to fully raise the press foot  20  to its first level  23 . Return fluid from the press foot cylinder  21  passes through the press foot return line  83 . A two-way, two-position, cam operated valve  84  controls a second fluid path from the sequence valve  81  to the feed drawer cylinder  34 . The cam operated valve  84  assures that fluid cannot flow to the feed drawer cylinder  34  unless the bucking foot  50  is in its fully withdrawn position clearing the path of the feed drawer  30 . When the press foot  20  is at its first level  23 , the sequence valve  81  switches to cause the feed drawer  30  to be fully extended into registration with the breech  10  of the machine. When the feed drawer  30  has reached its fully extended position, the operator pulls the lever  79  of the three position switch  76  back. With the lever  79  in this position, fluid flows through a second sequence valve  85  to the press foot cylinder  21  to lower the press foot  20  to its second level  24  to dispense loose earth M from the feed drawer  30  into the breech  10 . A three-way, two-position, cam operated valve  86  is depressed to block the pilot line  87  in the press foot system and thus prevent further lowering of the press foot  20  beyond the second level  24 . When the pilot line  87  is blocked, the three-way, two-position cam operated valve  86  vents back to the reservoir  72 . When the three-way valve  86  cuts off, the second sequence valve  85  opens and allows the feed drawer cylinder  34  to vent and retract or withdraw the feed drawer  30  into registration with the hopper  60 . When the feed drawer  60 , is in registration with the hopper  60  a second two-way, two-position, cam operated valve  88  is depressed to allow the bucking foot  50  to be lowered. In this condition, the operator releases the lever  79  of the second lever operated valve  76  and pushes the lever  89  of the first lever operated valve  74  associated with the bucking foot  50 . If the second two-way, two-position valve is depressed, the bucking foot cylinder  41  will be operated and the bucking foot  50  fully lowered to close the upper end of the breech  10 . With the bucking foot  50  in this position, the operator releases the second lever  89  and once again pushes the first lever  79 . This operates the press foot cylinder  21 , causing the press foot  20  to be raised to its third level  25  in the breech  10 . The third level  25  of the press foot  20  is determined by the selected pressure of a relief valve  91 . When the block has been pressed, the operator releases the first lever  79  and pulls the second lever  89  to raise the bucking foot  50  to its fully retracted position. This automatically operates the first two-way, two-position, cam operated valve  84  and allows the cycle to be repeated. A pressure gauge  91  is provided to monitor the pressure at the relief valve  91  and check valves  93  and  94  complete the hydraulic circuit. 
     Thus, it is apparent that there has been provided, in accordance with the invention, a machine and method that fully satisfy the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments and methods thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.