Patent Publication Number: US-2009226257-A1

Title: Screed system

Description:
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/035,237, filed Mar. 10, 2008, 61/051,873, filed May 9, 2008, and 61/102,695 filed Oct. 3, 2008, each of which is hereby expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     The present disclosure is related to screeding concrete and particularly to a screed system including a screed-rail system supporting a screed assembly. More specifically, the present disclosure is related to a screed-rail system supporting a screed assembly having a screed plate. 
     SUMMARY 
     According to the present disclosure, a screed system for placing uncured concrete includes a screed-rail system and a screed assembly supported on the screed-rail system. The rail system includes a pair of rails spaced apart and parallel to one another. The screed system is supported between the rails and is moved along the rails to work uncured concrete to a final grade level. 
     In illustrative embodiments, the rail system further includes adjustment means for adjusting a vertical position of each rail to cause the screed assembly to be supported in a final-grade producing position so that the final grade level of uncured concrete is formed. In illustrative embodiments, the adjustment means includes a frame arranged to pivot about a pivot axis to cause an end of each rail to be freed so that the screed-rail system can be repositioned from a first working area to a second working area to work uncured concrete at the second working area at a final grade level without disrupting the uncured concrete at the first working area. 
     In illustrative embodiments, the screed assembly includes a screed plate and a screed-height controller. The screed-height controller includes a height-adjustment mechanism coupled to the screed plate and configured to move the screed plate vertically. The screed-height controller also includes height-control means for controlling movement of the height-adjustment mechanism to cause the screed plate to move vertically in response to a reference signal corresponding to a target grade to maintain the screed plate in a final-grade producing position. 
     Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a perspective view of a first embodiment a screed system in accordance with the present disclosure, showing that the screed system includes two adjustable rail assemblies, and an automatic adjustable screed assembly, in accordance with the present disclosure, supported on the two adjustable rail assemblies and showing that the automatic adjustable screed assembly includes a screed-height controller which adjusts the vertical position of a screed plate included in the screed assembly relative to a reference laser signal emitted by a grade laser located outside the work area; 
         FIG. 2  is a perspective view of a second embodiment of a screed system in accordance with the present disclosure, showing that the screed assembly may include a fixed-position screed assembly supported between the adjustable rail assemblies of  FIG. 1 ; 
         FIG. 3  is an enlarged elevation view of a third embodiment of a rail-height adjuster showing that the rail-height adjuster is supported on a reference-datum pin illustratively mounted in earth below a finished grade level (phantom line) of uncured concrete and suggesting that the rail-height adjuster is configured to adjust the vertical position of a rail relative to the reference-datum pin; 
         FIG. 4  is an enlarged perspective view of the rail-location adjuster of  FIGS. 1 and 2  suggesting that the rail-location adjuster moves the rail and distal rail-height adjuster by rotating the rail-location adjuster about a pivot axis in an illustrative counter-clockwise direction (double solid arrow) and showing that the rail-location adjuster also includes a second embodiment of a rail-height adjuster that is configured to cooperate with another rail-height adjuster to change the vertical position of the rail manually; 
         FIG. 5  is a perspective view of a third embodiment of a screed system in accordance with the present disclosure, the screed system includes a pair of adjustable rail assemblies and each rail assembly illustratively includes the first embodiment of the rail-height adjuster coupled to a proximal end of the rail, shown in the lower left of  FIG. 5 , and a second embodiment of a rail-location adjuster coupled to the distal end of the rail, shown in the upper right of  FIG. 5 ; 
         FIG. 6  is an enlarged partial perspective view of the distal rail-location adjuster of  FIG. 5  showing that the rail-location adjuster is arranged to lie on uncured concrete at a final grade level and is configure to allow the rail to rotate about a pivot axis in a clockwise direction (solid single arrow) relative to a float plate included in the rail-location adjuster; 
         FIG. 7  is an enlarged partial elevation view of the rail-location adjuster of  FIGS. 5 and 6  with portions broken away to reveal a fourth embodiment of a rail-height adjuster that is coupled to the rail near the distal end of the rail where the rail-location adjuster is coupled to the rail and suggesting that when the proximal end of the rail is lifted and rotated about the pivot axis, the rail-height adjuster disengages the reference-datum pin and the rail-location adjuster allows the rail assembly to be pulled toward the proximal end of the rail as suggested in  FIG. 8 ; 
         FIG. 8  is a view similar to  FIG. 7  showing the adjustable rail assembly in an illustrative process of moving from a first working area to a second working area and showing that that the rail-location adjuster supports the rail assembly during movement by floating on the uncured concrete positioned at final grade level until the rail-height adjuster can be mounted on a new reference datum pin; 
         FIG. 9  is a perspective view of a fourth embodiment of a screed system in accordance with the present disclosure showing that the screed system includes a third embodiment of a rail-location adjuster including a handle coupled to the rail and a support wheel coupled to the handle and suggesting that a user pulls downwardly (solid arrow) on the handle to cause the handle and rail to rotate together as a unit about a pivot axis defined by a wheel axle in the support wheel; 
         FIG. 10  is an enlarged partial perspective view of an automatic adjustable screed assembly in accordance with the present disclosure, showing that the automatic adjustable screed assembly includes a screed plate configured to place uncured concrete at a final grade level and a height-adjustment mechanism, a height-control assembly coupled to the screed plate to determine the vertical position of the screed plate relative to a reference signal, illustratively a laser signal, and a height-adjustment mechanism configured to move the screed plate vertically in response to a signal from the height-control assembly; 
         FIG. 11  is a partial perspective view of a screed assembly showing that the screed assembly illustratively includes a handle coupled to a screed plate and a first embodiment of a user-input device, illustratively a multi-position switch, coupled to a handle to control operation of the height-adjustment mechanism; 
         FIG. 12  is an enlarged partial elevation view of the user-input device of  FIG. 11 ; 
         FIG. 13  is an enlarged partial perspective view of the rail-location adjuster of  FIG. 10  showing that the handle and the support are adjustable relative to the rail so that a user can manually reconfigure the distance between the support wheel and the rail; 
         FIG. 14  is an enlarged partial perspective view of a junction box for an electrical system included in the screed assembly of  FIGS. 1 and 10 ; 
         FIG. 15  is an enlarged partial perspective view of a second embodiment of a user-input device showing that the user-input device includes an operation mode switch configured to allow a user to select an automatic control mode or a manual control mode and a manual-movement switch configured to allow a user to control movement of a height-adjustment mechanism manually; 
         FIG. 16  is a block diagram of a first embodiment of a height controller in accordance with the present disclosure, showing that the height controller includes a sensor system including a left-side reference-signal receiver and a right-side reference-signal receiver and a centralized control system coupled to both reference-signal receivers and configured to send actuation signals to a left-side height-adjustment mechanism and a right-side adjustment mechanism; and 
         FIG. 17  is a block diagram of a second embodiment of a height controller in accordance with the present disclosure, showing that the height controller includes a sensor system including a left-side reference-signal receiver and a right-side reference-signal receiver and a de-centralized control system including a left-side controller and a right-side controller each coupled to their companion reference-signal receivers and each configured to send actuation signals to their companion height-adjustment mechanisms. 
     
    
    
     DETAILED DESCRIPTION 
     A screed system includes may include any of a number of combinations of screed-rail systems and screed assemblies as disclosed herein. For example, the screed system may include a first embodiment of a screed system  10  is shown in  FIG. 1 , a second embodiment of a screed system  100  is shown in  FIG. 2 , a third embodiment of a screed system  200  is shown in  FIG. 5 , or a fourth embodiment of a screed system  300  is shown in  FIG. 9 . A first embodiment of a screed assembly  14  is shown in  FIGS. 1 and 9  wherein screed assembly  14  is an automatic adjustable screed assembly. A second embodiment of a screed assembly  114  is shown in  FIGS. 2 and 5  wherein screed assembly  114  is a fixed-height screed assembly. A first embodiment of a rail-height adjuster  18  is shown in  FIGS. 1 ,  2 , and  5 , a second embodiment of a rail-height adjuster  118  is shown in  FIGS. 1 ,  2 ,  4 , and  5 , a third embodiment of a rail-height adjuster  218  is shown in  FIG. 3 , and a fourth embodiment of a rail-height adjuster  318  is shown in  FIG. 5 . A first embodiment of a rail-location adjuster  36  is shown in  FIG. 1 ,  2 , and  4 , a second embodiment of a rail-location adjuster  136  is shown in  FIGS. 5-8 , and a third embodiment of a rail-location adjuster  236  is shown in  FIG. 9 . An illustrative embodiment of an adjuster  72  is shown in  FIGS. 1 ,  9 , and  10 . A first embodiment of a height controller  82  is shown diagrammatically in  FIG. 16  and a second embodiment of a height-controller  182  is shown in  FIG. 17 . 
     Screed system  10 , as shown in  FIG. 1 , includes two adjustable rail assemblies  12  and an automatic adjustable screed assembly  14  supported between adjustable rail assemblies  12 . Each of the adjustable rail assemblies  12  includes a rail  16  adapted to support screed assembly  14  and rail-height adjustment means  18  for adjusting the vertical position of rail  16  to cause screed assembly  14  to be supported in a final-grade producing position so that a final grade level  20  of uncured concrete is formed as screed assembly  14  is moved along rail  16 . 
     As suggested in  FIG. 1  and shown in  FIG. 2 , a first embodiment of rail-height adjuster  18  includes a base  22  and an adjustment mechanism  24 . A first end  25  of rail  16  is coupled to adjustment mechanism  24  to move therewith. Adjustment mechanism  24  is arranged to extend downwardly to mount on base  22  to move vertically relative to base  22  below. Base  22 , as shown in  FIGS. 1 and 2 , is configured to be supported by earth  50 . Base  22  may be supported by earth  50  or other material that cooperates to define a rough grade level  19  below final grade level  20 . A second embodiment of rail-height adjuster  118  is shown in  FIG. 4 , a third embodiment of rail-height adjuster  218  is shown in  FIG. 3 , and a fourth embodiment of rail-height adjuster  318  is shown in  FIG. 7 . 
     As shown in  FIGS. 1 and 2 , adjustment mechanism  24  includes a crank handle  28  configured to rotate about a crank axis  30 , a threaded rod  32 , and a threaded receiver  34 . Crank axis  30  is defined by threaded rod  32 . Threaded rod  32  is coupled to crank handle  28  and arranged to rotate about crank axis  30 . Threaded receiver  34  is coupled to first end of rail  16  and is configured to receive threaded rod  32  as shown in  FIG. 3 . Threaded receiver  34  is configured to convert the rotational movement of threaded rod  32  into vertical movement of the first end  25  of rail  16  as suggested in  FIGS. 1 and 2 . 
     Screed system  10  further includes rail-location adjuster means  36  for pivoting rail  16  about a pivot axis  60  to cause a first end  25  of rail  16  to be freed so that screed system  10  may be repositioned from a first working area  41  to a second working area  42  to work uncured concrete at second working area  42  final grade level  20  without disrupting the uncured concrete at first working area  41 . A first embodiment of rail-location adjuster  36  is shown in  FIGS. 1 ,  2 , and  4 , a second embodiment of rail-location adjuster  136  is shown in  FIGS. 5-8 , and a third embodiment of rail-location adjuster  236  is shown in  FIGS. 9 and 13 . 
     As shown in  FIGS. 1 ,  2 , and  4 , the first embodiment of rail-location adjuster  36  is illustratively shown as a support dolly  40  that includes a handle  44  coupled to an opposite second end  26  of rail  16 , a support base  46 , and a rail pivot  48  interconnecting support base  46  to handle  44 . Support base  46  is arranged to support handle  44  and rail  16  during movement of screed assembly  14  along rail  16 . Rail pivot  48  is configured to support handle  44  and rail  16  during movement of screed system  10  from first working area  41  to second working area  42 . 
     As shown in  FIGS. 1 ,  2 , and  4 , support dolly  40  further includes the second embodiment of rail-height adjuster  118 . Illustratively, rail-height adjuster  118  interconnects rail  16  to handle  44 . Rail-height adjuster  118 , as shown in  FIG. 4 , includes an adjustment mechanism  124  and a base  122 . Base  122  is coupled to handle  44  and to rail  16 . Adjustment mechanism  124  is arranged to extend downwardly to couple with base  122  to mover vertically relative to base  122  and handle  44 . Base  122  is configured to be supported by handle  44  and support base  46  of rail-location adjuster  36 . 
     As shown in  FIGS. 1 ,  2 , and  4 , adjustment mechanism  124  is similar to adjustment mechanism  24  and includes crank handle  28  configured to rotate about crank axis  30 , a threaded rod  32 , and a threaded receiver  134 . Threaded receiver  134  is coupled to base  122  and is configured to receive threaded rod  32  as shown in  FIG. 4 . Threaded receiver  134  is configured to convert the rotational movement of threaded rod  32  and crank handle  28  into vertical movement of the second end  26  of rail  16  as suggested in  FIGS. 1 ,  2 , and  4 . 
     Illustratively, each of the screed systems  10 ,  100  as shown in  FIGS. 1 and 2  includes a pair of the first embodiments of rail-height adjusters  18  coupled to first end  25  of rail  16 . Screed system  10  further includes a pair of the first embodiments of rail-location adjusters  36  interconnected to second end  26  of rail  16  by the second embodiment of rail-height adjusters  118 . Rail-height adjusters  18 ,  118  cooperate together so that a user can make level adjustments to screed system  10 ,  100 . 
     As illustratively shown in  FIG. 1 , an automatic adjustable screed assembly  14  may rest on rails  16  and adjust the vertical position of screed plate  70  in reference to a reference datum  74 , illustratively a laser signal emitted from a grade laser  90 . Alternatively, a stationary screed assembly  114  may be used with screed system  100 ,  200  as shown in  FIGS. 2 and 5 . Final grade level  20  is achieved through manual adjustment of rail-height adjuster  18 ,  118 ,  218 ,  318  when using stationary screed assembly  114 . 
     Illustratively, the third embodiment of rail-height adjuster  218  is shown in  FIG. 3 . Rail-height adjuster  218  includes adjustment mechanism  24  similar to the first embodiment of rail-height adjuster  18  and a base  222 . Adjustment mechanism  24  is arranged to extend downwardly to mount on base  222  to move vertically relative to base  222 . Base  222 , as shown in  FIG. 3 , is illustratively mounted in earth  50  and supported by earth  50 . Base  222  illustratively includes a datum pin  120  and a socket  126 . Datum pin  120  is mounted in earth  50  and socket  126  is arranged to set on datum pin  120  to provide a connection point for adjustment mechanism  24  to set on during screeding. 
     As suggested in  FIG. 7 , a fourth embodiment of rail-height adjuster  318  coupled in close proximity to first end  25  of rail  16 . Rail-height adjuster  318  includes an adjustment mechanism  324  and a base  322 . Adjustment mechanism  324  is arranged to extend downwardly to mount on base  322  and configured to move rail  16  vertically relative to base  322 . Base  322 , as suggested in  FIGS. 7 and 8 , is a datum pin  120  mounted in earth  50  so that a first portion of datum pin  120  is within in earth  50  and a second portion extends upwardly above earth  50 . 
     Adjustment mechanism  324 , as illustrated in  FIG. 7 , includes a drive head  128 , a threaded rod  330 , and a threaded receiver  334 . Drive head  128  is coupled to a top end of threaded rod  330  and arranged to be rotated about a crank axis  30  to rotate threaded rod  330 . Threaded receiver  334  includes a mounting bracket  130  and a socket  132 . Mounting bracket  130  is coupled to rail  16  and formed to receive threaded rod  330 . Mounting bracket  130  is further configured to transform the rotational movement of threaded rod  330  into vertical movement of mounting bracket  130  and rail  16 . Socket  132  is coupled to mounting bracket  130  and arranged to extend downwardly and mate with datum pin  120 . 
     In illustrative use, rail-height adjuster  318 , as shown in  FIGS. 7 and 8 , is used to control the vertical position of rail  16  by first placing datum pin  120  in earth  50  and placing adjustment mechanism  324  on datum pin  120 . As an example, a user may require top surface  148  of rail  16  to be positioned four inches above final grade level  20 . To do so, datum pin  120  may be positioned so that a top portion is always two inches below final grade level. User will then use adjustment mechanism  324  so that the bottom of socket  126  is six inches below top surface  148 . Every time rail  16  is positioned on datum pin  120 , top surface  148  will be four inches above final grade level  20 . The six inch adjustment accounts for the two inches that datum pin  120  is below final grade level  20  and the four inches the user plans for top surface  148  to be above final grade level  20 . Any of a number of configurations may be selected by a user and this is but one illustrative example of how rail-height adjuster  318  may be used in accordance with the present disclosure. 
     The use of rail-height adjusters  218 ,  318  facilitates the use of datum pins  120  which are positioned either below or above a final grade level  20  which represents the planned grade of the concrete to be placed. When a datum pin  120  is positioned below final grade level  20 , uncured concrete can be placed near and around rail-height adjuster  218 ,  318  and when rail-height adjuster  218 ,  318  is removed from uncured concrete placed at final grade level  20 , datum pin  120  is covered by the uncured concrete and remains in position after placement of the concrete. In contrast, rail-height adjuster  18 , which includes base  22 , is configured to be positioned on rough grade  19  and no datum pin is used. 
     As shown in  FIGS. 5-8 , a second embodiment of a rail-location adjuster  136  is illustratively shown as a support float  52 . Support float  52  includes a float plate  54 , a float coupler  56 , and a pivot bracket  58 . Float plate  54  is positioned to lie on and be supported by uncured concrete at final grade level  20 . Float coupler  56  is coupled to opposite second  26  end of rail  16  and interconnected to float plate  54  by pivot bracket  58 . Pivot bracket  58  allows float coupler  56  and rail  16  to rotate together as a unit about a pivot axis  60  relative to float plate  54  as suggested in  FIG. 7  and shown in  FIG. 9 . 
     As shown in  FIG. 7 and 8 , float coupler  56  is secured to first end  25  of rail  16  by a set of fasteners  266 . Pivot bracket  58  is coupled to float plate  54  by a set of fasteners  270 . Pivot bracket  58  includes a pivot pin  62  and a pivot flange  65 . Pivot pin  62  is arranged to extend through pivot flange  65  and float coupler  56 . Pivot pin  62  defines pivot axis  60  as shown in  FIGS. 5 and 6 . 
     Float plate  54  has a generally planar lower surface  268 , as shown in  FIG. 7 , which lies in confronting relation with a concrete surface  272  which supports support float  52 . Illustratively, concrete surface  272  is a pad of cured concrete  274 , but maybe a pad of uncured concrete at final grade level  20 . Once first working area  41  has been worked to a final grade level  20 , support float  52  is configured to allow a user to lift second end  26  of rail  16  as suggested in  FIG. 7  (a phantom arrow  276 ) and move screed system  200  in a longitudinal direction  278  with support float  52  on uncured concrete  280  as shown in  FIG. 8 . 
     An illustrative process for moving screed system  10  is suggested in  FIGS. 7 and 8 . Illustratively, when second end  26  of rail  16  is lifted, float coupler  56  and rail  16  pivot about pivot pin  62 . A wall  282  of float coupler  56  is positioned so that when rail  16  is lifted a sufficient distance, wall  282  engages pivot flange  65 . Engagement of wall  282  with pivot flange  65  transmits rotation of float coupler  56  about pivot pin  62  to support float  52  thereby raising a proximal edge  284  of float plate  54 . Rail  16  is then pulled in longitudinal direction  278  with support float  52  supporting adjustable rail assembly  12  on uncured concrete  280  in a manner similar to a bull float commonly used in the concrete placement industry. 
     After adjustable rail assembly  12  is moved from first working area  41  to second working area  42 , rail  16  is lowered such that rail-height adjuster  318  engages another datum pin  120 ′. Datum pin  120 ′ is then responsible for supporting the weight of first end  25  of rail  16  and support float  52 . 
     As shown in  FIGS. 9 and 13 , a third embodiment of a rail-location adjuster  236  includes a handle  64  coupled to an opposite second end  26  of rail  16 , a support wheel  66 , and a wheel axle  68  interconnecting support wheel  66  to handle  64 . Wheel axle  68  defines pivot axis  60  to allow handle  64  and rail  16  to be rotated together as a unit about pivot axis  60  relative to support wheel  66  to move screed system  300  from first working area  41  toward second working area  42  without disrupting uncured concrete at final grade level  20  in first working area  41 . 
     As shown in  FIG. 4 , the first embodiment of rail-location adjuster  36  is a support dolly  40 . Support dolly  40  includes handle  44  which includes a handle crossbar  246  with a pair of grips  247 ,  248  on each of handle crossbar  246  that are configured to be gripped by a user when repositioning screed system  10 . Handle  44  further includes a first handle leg  249 , and a second handle leg  250  each coupled to handle crossbar  246  and extending downwardly toward rail  16 . First handle leg  249  includes a support base  46 , a rail pivot  48 , and a leg bar  252 . 
     Support dolly  40  further includes rail-height adjuster  118  and a rail-adjuster guide  254  which couples rail-height adjuster  118  to support dolly  40 . Rail-adjuster guide  254 , as shown in  FIG. 4 , includes an upper crossbar  255 , a lower crossbar  256 , and a pair of clamps  258  coupled to each side of upper crossbar  255 . Clamps  258  engage companion first and second handle legs  249 ,  250  to maintain position of rail-height adjuster  118  relative to handle  44 . Each clamp  258  includes a pair of clamp blocks  259 ,  260  and a clamp handle  262 . Clamp handle  262  acts on clamp blocks  259 ,  260  to draw clamp blocks  259 ,  260  together so that clamp blocks  259 ,  260  frictionally engage leg bar  252  of handle  44  to lock rail-adjuster guide  254  in position relative to handle  44 . 
     As shown in  FIG. 4 , base  122  of rail-height adjuster  118  is coupled to lower crossbar  256  and to rail  16  by a stringer  264 . Base  122  is illustratively not coupled to upper crossbar  255 , but threaded rod  32  of adjustment mechanism  124  extends through upper crossbar  255 . Illustratively, rail-adjuster guide  254  is configured to provide gross adjustment of the relative heights of rail  16  by moving upper crossbar  255  and clamps  258  along handle legs  249 ,  250  of handle  44 . Fine adjustment of rail  16  is accomplished by adjustment mechanism  124 . 
     An automatic adjustable screed assembly  14 , as shown in  FIGS. 1 ,  9 , and  10 , includes a screed plate  70  and adjuster means  72  for supporting screed plate  70  and for moving screed plate  70  vertically in response to a reference datum  74  to cause screed plate  70  to be adjusted to a final-grade producing position so that uncured concrete is placed at a final grade level  20  relative to reference datum  74  as adjuster means  72  is moved over a first working area  41 . 
     As shown in  FIGS. 1 ,  9 , and  10 , adjuster  72  includes a height-control assembly  76  coupled to screed plate  70  to move therewith and a height-adjustment mechanism  78  coupled to screed plate  70  to move screed plate  70  relative to height-adjustment mechanism  78 . Illustratively, height-control assembly  76  is configured to measure a distance between an actual position of screed plate  70  and the final-grade producing position. Height-control assembly  76  is configured to cause height-adjustment mechanism  78  to move screed plate  70  from the actual position toward the final-grade producing position to cause the distance to become relatively smaller and a final grade level  20  to be produced. 
     A screed-height controller  80 , as suggested in  FIGS. 9 and 10  and shown in  FIGS. 14-17 , includes screed plate  70 , height-adjustment mechanism  78 , and height-control means  82  for controlling the movement of height-adjustment mechanism  78  to cause screed plate  70  to move vertically in response to a reference signal  74  corresponding to a target grade to maintain screed plate  70  in a final-grade producing position such that uncured concrete is worked to final grade level  20 . 
     Illustratively, height controller  82  includes a sensor system  84 , a control system  86 , and a user-input device  88 . Sensor system  84  is coupled to screed plate  70  to move therewith and configured to receiver reference signal  74  emitted illustratively from grade laser  90 . Control system  86  is configured to receive an input signal from sensor system  84  and to transmit an output signal to height-adjustment mechanism  78  to cause height-adjustment mechanism  78  to move screed plate  70 . User-input device  88  is configured to be in one of an automatic mode or a manual mode. When user-input device  88  is in automatic mode, control system  86  is connected to sensor system  84  and receives input signal from sensor system  84 . When user-input device  88  is in manual mode, control system  86  is connected to user-input device  88  and receives input signal from user-input device  88 . 
     As shown in  FIGS. 1 and 9 , sensor system  84  of height controller  82  includes a first reference-signal receiver  92  and a second reference-signal receiver  94 . First reference-signal receiver  92  is coupled to a first end of screed plate  70  and a second reference-signal receiver is coupled to an opposite second end of screed plate  70 . Illustratively, reference-signal receivers  92 ,  94  extend upwardly away from screed plate  70  toward reference signal  74  as shown in  FIGS. 1 ,  9 , and  10 . 
     A first embodiment of user-input device  88 , as shown in  FIG. 15 , includes a switch housing  96 , an operation mode switch  98 , and a manual-movement switch  101 . Operation mode switch  98  illustratively is a two position switch where the first position is an automatic mode and the second position is a manual mode. Manual-movement switch  101  is configured to send an input signal to control system  86  in response to operation mode switch  98  arranged in manual mode. Operation mode switch  98  and manual-movement switch  101  are both mounted in switch housing  96 . 
     A second embodiment of user-input device  88 , as shown in  FIGS. 11 and 12 , includes a switch body  102  and a lever  104  coupled to move relative to switch body  102 . Lever  104  is movable between an automatic mode position  106  (solid) illustrated in  FIG. 11  wherein user-input device  88  is in automatic mode and a stationary mode position  108  (phantom) wherein user-input device is in manual mode and control system  86  does not send an output signal to height-adjustment mechanism  78 . Lever  104  is movable to a third position  110  (phantom) as shown in  FIG. 11 , wherein user-input device  88  is in the manual mode and control system  86  commands height-adjustment mechanism  78  to move screed plate  70  upwardly so as not to disturb uncured concrete at final grade level  20  while screed assembly  14  is moved from first working area  41  to second working area  42 . 
     Stationary screed assembly  114 , as shown in  FIGS. 2 and 5 , includes screed plate  70 , plate vibrator  140 , a pair of screed supports  142 , and a screed handle  144 . Plate vibrator  140  is coupled to screed plate  70  and configured to vibrate screed plate  70 . Plate vibrator includes a power unit  224  coupled to a vibrator  226  as shown in  FIG. 11 . Screed handle  144  includes a screed-handle  228  and a pair of hand grips  229 ,  230 . Illustratively, screed handle  144  is mounted around plate vibrator  140  to screed plate  70  so that a user may push or pull screed assembly  114  along the length of rails  16 . Screed assembly  114  is supported on rails  16  by a pair of screed supports  142  mounted on each end of screed plate  70 . 
     Screed assembly  114 , as shown in  FIGS. 2 and 5 , includes a hanger  150  coupled to screed plate  70  and a slide plate  146  coupled to hanger  150  and positioned to engage a top surface  148  of rail  16 . Slide plate  146  comprises a low friction material which facilitates screed assembly  114  sliding along rail  16  during the screeding process. When using stationary screed assembly  114 , final grade level  20  of uncured concrete is achieved by movement of rails  16  relative to a datum pin  120 . When using automatic adjustable screed assembly  14 , final grade level  20  of uncured concrete is achieved by movement of screed plate  70  relative to reference datum  74 . 
     Automatic adjustable screed assembly  14 , as shown in  FIGS. 1 ,  9 , and  10 , includes screed plate  70 , plate vibrator  140 , screed handle  144 , and adjuster  72 . Screed assembly  14  is supported on rails  16  by a pair of adjusters  72  mounted to each end of screed plate  70 . As suggested in  FIGS. 1 and 9 , adjuster  72  includes height-control assembly  76  and height-adjustment mechanism  78 . 
     Height-adjustment mechanism  78 , as shown in  FIG. 10 , includes an actuator  152 , a rail follower  154 , and a support assembly  156 . Rail follower  154  is configures to ride on top surface  148  of rail  16  and configured to support actuator  152  coupled to rail follower  154  to move vertically relative to rail follower  154 . Support assembly  156  is interconnected to screed plate  70  and actuator  152  to move therewith as suggested in  FIG. 10 . Rail follower  154  includes a carriage  158  and a pair of posts  160  which are coupled to carriage  158  and engage support assembly  156  as actuator  152  moves vertically relative to rail  16 . 
     Carriage  158 , as shown in  FIG. 10 , includes a roller bracket  162  which is coupled to posts  160  and a pair of rollers  163 ,  164  coupled for rotation to roller bracket  162 . Each roller  163 ,  164  is configured to engage top surface  148  of rail  16 . Carriage  158  further includes a pair of lateral trailers  165 ,  166  that are configured to maintain height-adjustment mechanism  78  in the proper lateral position as it moves along rail  16 . 
     Lateral trailers  165 ,  166  each include an extension bar  168  coupled to roller bracket  162  and arranged to extend outwardly away from rail  16  and a trailer wheel  170  coupled to extension bar  168  and configured to engage a companion outer surface  171 ,  172  of rail  16 . Only outer lateral trailer  165  is shown in  FIG. 8 , but it is within the scope of the present disclosure to position the other lateral trailer  166  similarly on the inside of rail  16 . 
     As shown in  FIG. 10 , support assembly  156  includes a channel  174  and a channel bracket  176  coupled to channel  174  by a securing pin  178 . Securing pin  178  may be removed so that screed plate  70  may be coupled to support assembly  156  in multiple locations to provide gross adjustment of screed plate  70  relative to rail  16 . A pair of post guides  180  are coupled to channel bracket  176  and configured to receive posts  160  of rail follower  154 . Post guides  180  cooperate with posts  160  to allow actuator  152  to move in a substantially vertical direction  183  relative to rail  16 . 
     As shown in  FIG. 10 , support assembly  156  further includes a pair of mounts  184  and a clamp  186 . Mounts  184  and claim  185  cooperate to secure actuator  152  to channel bracket  176  so that actuator  152  is fixed to channel bracket  176 . Actuator  152  includes an actuator piston  188  which extends and retracts as depicted by arrow  183 . Movement of actuator piston  188  moves support assembly  156  vertically relative to rail  16  to change the vertical position of screed plate  70 . 
     Adjuster  72  further includes height-control assembly  76  which includes a control assembly  190  and a support bracket  192 . Support bracket  192  is secured to screed plate  70  by an illustrative pair of fasteners  194 . Support bracket  192  includes a mount  196  which supports control assembly  190  and a control-assembly mount plate  198  which is coupled to screed plate  70  by fasteners  194 . Mount  196  extends upwardly away from screed plate  70  as shown in  FIGS. 1 ,  9 , and  10 . 
     Control assembly  190  includes a power module  201 , a controller  202 , and a receiver  204 . Power module  201  is illustratively mounted on mount  196  and includes a battery (not shown) and a power switch  206  which is operable to turn power on and off to adjuster  72 . Controller  202  includes circuitry which processes signals received from receiver  204  and outputs control signals to operate actuator  152  to extend and retract actuator piston  188 . Illustratively, receiver  204  includes a light-sensitive receiver panel  208  which is configured to detect a laser signal  74 . Laser signal  74  is emitted from a grade laser  90  that includes a tripod  210  and an emitter head  212  which rotates about an emitter axis  214  as shown in  FIG. 10 . Emitter head  212  emits laser signal  74  which is indicative of a desired position of receiver  204 . 
     As further shown in  FIG. 10 , light-sensitive receiver panel  208  has a target  216 . If laser signal  74  is detected above target  216 , a signal is sent to controller  202  to extend actuator piston  188  to thereby raise receiver  204  to a position in which laser signal  74  is on target  216 . If laser signal  74  is detected by light-sensitive receiver panel  208  below target  216 , a signal is sent to controller  202  to retract actuator piston  188  to thereby lower receiver  204  to a position in which laser signal  74  is on target  216 . During the screeding process, screed plate  70  is moved along a pair of rails  16  and adjuster  72  is operable to constantly adjust the vertical position of screed plate  70  relative to rail  16  to so that screed plate  70  is in the final-grade producing position to cause final grade level  20  of uncured concrete to be formed as suggested in  FIG. 1 . 
     Automatic adjustable screed assembly  14  can be used with any of the embodiments of screed system  10 ,  100 ,  200 ,  300 . The fourth embodiment of screed system  300  includes automatic adjustable screed assembly  14  and screed frame  220 . A throttle  232 , as shown in  FIG. 11 , is mounted to screed handle  144  of screed frame  220 . Throttle  232  controls the speed of power unit  224  which thereby controls the magnitude of vibrations emitted from vibrator  226 . User-input device  88  is coupled illustratively near throttle  232  as shown in  FIGS. 9 and 11 . User-input device  88  allows a user to control whether automatic adjustable screed assembly  14  is controlled automatically or manually. 
     As shown in  FIG. 12 , the second embodiment of user-input device  88  is illustratively a three position switch. When the lever  104  is in automatic mode position  106  (shown solid and lowest position), adjuster  72  is operational to detect a laser signal  74  at receiver  204  and output a control signal to operate actuator  152  to extend and retract actuator piston  188 . Lever  104  is movable to stationary mode position  108  (shown in phantom and middle position) as shown in  FIG. 12 . When the lever  104  is in stationary mode position  108 , adjuster  72  is not operational and does not respond to laser signal  74 . 
     Lever  104  toggles between automatic mode position  106  and stationary mode position  108 . Lever  104  is further movable from stationary mode position  108  to a third position  110  (shown in phantom at top) as shown in  FIG. 12 . In third position  110 , lever  104  is biased and urged to return to stationary mode position  108 . Lever  104  acts as a momentary switch when in third position  110 . If a user applies a force to lever  104  to urge lever  104  to third position  110 , height-adjustment mechanism  78  will respond by extending actuator piston  188  of actuator  152  to raise screed plate  70  relative to rail  16  so that screed plate  70  may be moved over uncured concrete at final grade level  20  without disrupting the finished surface. 
     As shown in  FIG. 16 , control system  86  is illustratively a single controller where first reference-signal receiver  92  is connected by a first signal cable  285  to control system  86  and second reference-signal receiver  94  is connected a second signal cable  286 . Control system  86  is connected to each individual actuator by an actuator-command cable  288 . As suggested in  FIG. 16 , a power module  201  is coupled to control system  86  and power is supplied to each actuator  152  from power module  201  by actuator-command cables  288 . 
     As shown diagrammatically in  FIG. 17 , a first embodiment of power module  201  is a single power module separate from and connected to junction box  240  by power cable  242 . First embodiment of power module  201  provides all the necessary power to first and second reference-signal receivers  92 ,  94 , individual controllers  202 , and both height-adjustment mechanisms  78 . A second embodiment of power module  201  is suggested diagrammatically in  FIG. 16  wherein power module  201  is included in the same housing as control system  86 . The single second embodiment of power module  201  provides all the necessary power. 
     As shown in  FIG. 10 , a third embodiment of power module  201  is mounted on each adjuster  72 . The third embodiment of power module  201  illustratively provides power to each height adjuster  72 . As an example, two power modules  201  may be required when the third embodiment of power module  201  is used to power each reference-signal receiver  92 , its companion controller  202 , and its companion height-adjustment mechanism  78  all included in the individual adjuster  72 . 
     In another illustrative embodiment, user-input device  88  may be connected to a junction box  240  by control cable  238  as suggested in  FIG. 17 . A power cable  242  also interconnects power module  201  to junction box  240 . Junction box  240  splits power and the user-input signal to both adjusters  72  by a pair of power-control cables  244 . Each power-control cable  244  sends power from power module  201  and user-input commands from user-input device  88  to each adjuster  72  to multiple controllers  202 . Junction box  240  may also include power switch  206  movable between an on position where power is permitted to flow out of power module  201  and an off position where power is restricted from flowing out of power module  201 . 
     Height-adjustment mechanism  78  may be illustratively controlled by controller  202  receiving signals from receiver light-sensitive receiver panel  208 . In one example, controller  202  may be enclosed with light-sensitive receiver panel  208  within reference-signal receiver  92  as suggested in  FIG. 17 . 
     As shown in  FIGS. 9 and 13 , a fourth embodiment of screed system  300  includes automatic adjustable screed assembly  14  positioned on screed frame  220 . Screed frame  220  is shown with a first end  292  positioned in the lower left of  FIG. 9 . A second end  294  is positioned in the upper right of  FIG. 12  and is configured to be supported by two posts  295  and  296 . Posts  295 ,  296  are each secured to a respective rail  16   a  and  16   b  by a coupler  298  configured to clamp posts  295 ,  296  in position relative to coupler  298 . The clamping action of coupler  298  provides for adjustment of the height of rails  16   a ,  16   b  relative to rough grade  19 . Thus, gross adjustment of second end  294  of screed frame  220  can be made before concrete is placed initially. 
     First end  292  of screed frame  220  is supported on a pair of rail-location adjusters  236  in accordance with the present disclosure. Each rail-location adjuster  236  includes handle  64 , support wheel  66 , and wheel axle  68  interconnecting support wheel  66  to handle  64 . As suggested in  FIG. 9 , two users, one on each handle  64 , rotate rails  16   a ,  16   b  about pivot axis  60  to lift second end  294  out of contact with rough grade  19  in a counter-clockwise direction  301 . After second end  294  of screed frame  220  has been lifted out of contact with rough grade  19 , users may move screed rail system from first working area  41  to second working area  42  without disturbing uncured concrete at final grade level  20 . 
     Screed frame  220 , as shown in  FIG. 9 , further includes a tie rod  302  positioned at second end  294  and configured to secure rails  16   a ,  16   b  together at an appropriate spacing. Rails  16   a ,  16   b , as shown in  FIG. 14 , are releasably coupled to each handle  64 . Handle  64  is releaseably coupled to a cross bar  304  included in screed frame  220 . The releasable coupling of various components of screed frame  220  facilitates easy assembly and disassembly of screed system  300  while providing a generally rigid structure when in use. 
     Screed frame  220  further includes a rail coupler  306  coupled to rail  16 . Rail coupler  306  includes a first plate  307  and a post  310  cantilevered to first plate  307 . A second plate  308  is coupled to the opposite side of rail  16  and secured to first plate  307  by fasteners (not shown). Handle  64  includes two support bars  311 ,  312  coupled to support wheel  66  by wheel axle  68 . Support wheel  66  is positioned to lie between support bars  311 ,  312  and wheel axle  68  is arranged to extend through support bars  311 ,  312  and support wheel  66 . 
     As shown in  FIG. 13 , each support bar  311 ,  312  is formed to include a plurality of positioning holes  314 . First and second plates  307 ,  308  are formed to include a plurality of positioning holes  316  (not shown) coaxially aligned with positioning holes  314 . A handle-frame retention pin  320  is arranged to extend through positioning holes  314 ,  316  to retain handle  64  in a fixed position relative to rail  16 . Handle-frame retention pin  320  is configured to be removable so that the vertical position of handle  64  may be changed relative to rough grade  19 . Illustratively, a user removes handle-frame retention pin  320  and adjusts the position of rail  16  to a new location and re-inserts handle-frame retention pin  320  through holes  314 ,  316 . 
     As shown in  FIG. 13 , first plate  307  includes a cantilevered tab  326  formed to include a through hole (not shown). Cantilevered tab  326  is arranged to extend away from rail  16  generally parallel to rough grade  19 . Cross bar  304  includes a mount plate  332  having a cantilevered mounting tab  328  formed to include a through hole (not shown) coaxially aligned with the through hole formed in cantilevered tab  326  when screed frame  220  is assembled. An assembly pin  366  is arranged to extend axially through both through holes coupling cross bar  308  to rail  16  and facilitating efficient disassembly of screed frame  220 . Mount plate  332  is coupled to cross bar  304  by a fastener  336   
     Screed frame  220 , as shown in  FIG. 13 , includes a cross-bar coupler  338  including a first cross-bar plate  339  coupled to one side of cross bar  304  and a second cross-bar plate  340  coupled to the opposite side of cross bar  304 . A set of fasteners  348  interconnect first and second cross-bar plates  339 ,  340  together through cross bar  304 . Cross-bar coupler  338  further includes a post  342  cantilevered onto first cross-bar plate  339  and extending toward screed plate  70 . A strut  344  is positioned on each post  310 ,  342  and includes through holes (not shown) configured to receive pins  346  when strut  344  is positioned on posts  310 ,  342  as suggested by  FIG. 13 . Pins  346  are retained in place by retainers  350  which are removable so that pins  346  may be removed from screed frame  220 . Illustratively retainers  350  are retainer pins, but any suitable alternative may be used. 
     Handle  64 , as shown in  FIG. 13 , further includes a grip handle  352  including a cross-handle bar  354 , a first handle support  355 , and a second handle support  356 . Two brackets  357 ,  358  are coupled to companion support bars  311 ,  312  to facilitate disassembly of handle  64 . First and second handle supports  355 ,  356  are inserted through companion brackets  357 ,  358  and secured to support bars  311 ,  312  by companion fasteners  359 ,  360 . A post (not shown) extends from each bracket  357 ,  358  and is sized to be received in a space inside support bars  311 ,  312  of grip handle  352 . Removable pins  361 ,  362  are received through each support bar  311 ,  312  and posts and are secured in place by retainer  364 . Assembly of handle  64  in this manner allows for improved assembly and disassembly efficiency when moving from site to site. 
     In some embodiments, support wheel  66  may be omitted and replaced with a skid plate having a curved or angled surface such that the screed rail assembly may be rotated to lift one end out of worked concrete at final grade level  20 . The skid plate is suitable for use on sub-grade surfaces having significant discontinuities or other surfaces where support wheels  66  of screed system  300  would not be suitable.