Patent Publication Number: US-6981819-B1

Title: Tilting screed

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a tilting screed and method for using same. 
   Screeds have been used for leveling and consolidating uncured concrete. These screeds usually include a horizontal member which is moved across the surface of the concrete to level the concrete and prepare it for finishing. Vibrators are sometimes used to cause the screed to vibrate against the surface of the concrete and to consolidate it. 
   It is desirable to be able to adjust the angle of the screed plate relative to the concrete surface. Sometimes it is desirable to lift the leading edge of the screed plate to allow more concrete under the plate for filling low areas. Other times it is desirable to lift the trailing edge of the screed plate to remove concrete from a high spot. 
   The prior art has utilized laser receivers for receiving a horizontal laser beam. These laser receivers include a visual indication as to whether or not the screed is resting on a concrete surface that is above or below horizontal. However, these prior art devices have not provided a means for automatically tilting the screed plate in response to the laser sensor determining that either a filling action or a concrete removing action is necessary. 
   Therefore a primary object of the present invention is the provision of an improved tilting screed and method for using same. 
   A further object of the present invention is the provision of an improved tilting screed and method for using same which automatically tilts the screed in response to sensing whether the concrete surface is lower or higher than desired. 
   A further object of the present invention is the provision of an improved tilting screed and method for using same which utilizes a pivotal member attached to both of the first and second handles. 
   A further object of the present invention is the provision of a tilting screed and method for using same which utilizes a tilting member having two handles attached thereto and having a tilt actuator also attached thereto. 
   A further object of the present invention is the provision of a tilting screed and method for using same which senses a laser beam and which automatically actuates a tilt actuator for tilting the screed whenever the concrete is either above or below a predetermined level. 
   A further object of the present invention is the provision of a tilting screed and method for using same which is economical to manufacture, durable in use and efficient in operation. 
   BRIEF SUMMARY OF THE INVENTION 
   The foregoing objects may be achieved with a concrete screed for smoothing an uncured concrete surface. The screed includes a screed blade having first and second opposite ends, a leading edge, a trailing edge, and a flat bottom surface. The screed blade is elongated and has a longitudinal screed blade axis. The bottom surface is adapted to rest on the uncured concrete surface. A vibrator is mounted on the screed blade and is capable of actuation to cause vibration of the screed plate. A pivot member is pivotally mounted to the screed plate for pivotal movement about a horizontal pivot axis extending in the same general direction of the longitudinal screed plate axis. 
   A first handle and a second handle each have an attachment end mounted to the pivot member. The first and second handles also each have a gripping end opposite from the attachment end for gripping the handles. A tilt actuator is connected to both the pivot member and the screed plate. The tilt actuator is capable of actuation to cause the pivot member and the screed to rotate relative to one another about the horizontal pivot axis. 
   According to another feature of the present invention the first and second handles prevent rotation of the pivot member about the horizontal pivot axis when the gripping ends of the first and second handles are held at a constant height above the concrete surface. The tilt actuator causes the screed plate to pivot about the horizontal pivot axis relative to the pivot member during actuation of the tilt actuator. 
   According to another feature of the present invention a laser receiver is attached to the screed plate and is electrically connected to the tilt actuator for actuating the tilt actuator. The laser receiver is capable of sensing the height surface relative to a fixed horizontal height. The height detector actuates the tilt actuator in response to sensing when the concrete surface is either above or below a predetermined distance from the fixed horizontal height. 
   According to another feature of the present invention a laser beam extends horizontally at a fixed height. The height detector is capable of receiving the laser beam and calculating the distance of the laser beam from the concrete surface. 
   According to another feature of the present invention the tilt actuator comprises first and second actuator members that are longitudinally extensible with respect to one another when the tilt actuator is actuated. 
   According to another feature of the present invention the first and second handles are pivotally mounted to the pivot member for pivotal movement about first and second axis that are perpendicular to the horizontal pivot axis of the pivot member. 
   The foregoing objects may be achieved by a method comprising taking a screed plate having a bottom surface resting on the concrete surface, a pivot member pivotally mounted to the screed plate for pivotal movement about a horizontal pivot axis, and a pair of handles each having an attachment end attached to the pivot member and a gripping end for gripping by an operator. The method comprises sensing the distance of the screed plate resting on the concrete from a fixed horizontal height and tilting the screed plate about the horizontal pivot axis in response to the sensed distance of the screed plate from the fixed horizontal height being either above or below a predetermined distance. 
   A further feature of the method present invention comprises tilting the screed plate in a first direction about the horizontal axes in response to the sensed distance being above the predetermined distance and tilting the screed plate in a second direction opposite from the first direction about the horizontal pivot axes in response to the sensed distance being below the predetermined distance. 
   According to another feature of the method of the present invention the gripping ends of the first and second handles are held at a constant height during operation above the surface of the concrete during the sensing and tilting steps. This holds the pivot member against pivotal movement about the horizontal pivot axis during the sensing and tilting steps. 
   According to another feature of the method present invention the first and second handles are pivotally mounted to the pivot member for pivotal movement about first and second axes perpendicular to the horizontal pivot axis of the pivot member. The method comprises pivoting the first and second handles about the first and second axes while holding the pivot member against pivotal movement about the horizontal pivot axis. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is perspective view of the tilting screed of the present invention. 
       FIG. 2  is a sectional view taken along line  2 — 2  of  FIG. 1 . 
       FIG. 2A  is view similar to  FIG. 2 , but showing the screed plate tilted in a first direction. 
       FIG. 2B  is a view similar to  FIG. 2 , but showing the screed plate tilted in the opposite direction. 
       FIG. 3  is a schematic view showing the electrical interconnection of the parts. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1  a screed  10  includes a screed blade or plate  12  having a screed base  14  with a forward edge  16  and a rear edge  18 . A screed flange  20  extends vertically up from the rear edge  18  so that the screed blade or plate  12  is of an L-shaped configuration. The bottom surface of the screed base  14  is adapted to rest on an uncured concrete surface. 
   A pair of pivot ears  22 ,  24  are attached to the upper surface of the screed base  14  or to screed flange  20  by welding, bolting or other securing means. The pivot ears  22 ,  24  are L-Shaped in configuration and include a pivot member or bar  26  pivotally mounted therebetween for pivotal movement about a horizontal pivot axis designated by the numeral  28 . 
   Attached to the pivot member or bar  26  by a bolt  36  and extending upwardly therefrom is a mounting bracket  30  comprising an upstanding frame member  32  and a horizontal frame member  34 . Mounted to the horizontal frame member  34  is an actuator  38  which is pivotally attached at its upper end to actuator ears  48  for pivotal movement about the actuator axis  50 . The actuator  38  includes a cylinder  40  and a cylinder rod  42  which are longitudinally extensible with respect to one another. Preferably these are electronically actuated for extensible movement. An example of a preferred actuator  38  is manufactured by Danaher Motion under the part Number DE12-17W41-04-FPHHN. It is a 12–24 volt deactuator. The lower end of cylinder rod  42  is pivotally attached to rod receiving ears  44  for pivotal movement about the rod pivot  46 . As can be seen in  FIGS. 2 ,  2 A and  2 B, the horizontal pivot axis  28  of the pivot member or bar  26  is spaced from the rod pivot point  46  so that extension and retraction of the cylinder  40  and the cylinder rod  42  causes the screed plate  12  to pivot from its neutral position shown in  FIG. 2  to either its first tilt position shown in  FIG. 2A  wherein the rod  42  is extended or to its second tilt position shown in  FIG. 2B  wherein the rod  42  is in a retracted position. 
   Also mounted on the screed plate  12  is a vibrator mechanism  52  which is typical of other vibrating mechanisms utilized with screed plates. Extending upwardly from the screed plate  12  is a laser receiver assembly  54  comprising an upstanding support  56  and a laser receiver  58  mounted at the upper end thereof. The laser receiver  58  is adapted to receive a laser beam  60  emanating at a fixed horizontal level which provides a reference point for whether or not the screed plate  12  is above or below a predetermined distance from laser beam  60 . If the receiver  58  is above the horizontal laser beam  60  then the screed plate  12  is resting on a concrete surface that is above the desired level. If the receiver  58  is at the same level as horizontal laser beam  60 , then the screed plate  12  is resting on a concrete surface at the desired level. If the receiver  58  is below the horizontal laser beam  60 , then the screed plate  12  is in a dip or depression in the concrete surface and filling is desired. 
   The upstanding member  56  is attached at its lower end to the screed flange  20 . A leveling angle member  62  extends horizontally from the upstanding member  56 . 
   A first handle  64  and second handle  66  are both pivotally mounted at their lower ends  68  to the pivot member or bar  26  so that they rotate about the horizontal pivot axis  28  in unison with the pivot member or bar  26 . However, the handles  64 ,  66  are pivotally mounted to the pivot member or bar  26  for pivotal movement about axes  70  which are perpendicular to the horizontal pivot axis  28 . The first and second handles  64 ,  66  each include an upper handle end  72 . When the upper handle end  72  is held at a constant height, the pivot bar  26  is held against rotation about horizontal pivot axis  28 . However, extension or retraction of the rod  42  in the tilt actuator  38  will cause the tilting of the screed plate  12  to the various orientations shown in  FIGS. 2 ,  2 A and  2 B. 
   Attached to the upper ends  72  of the handles  66 ,  68  are a pair of arms rests  74 . On the right handle  64 , is a right control  76  and on the second handle  66  is a left control handle  78 . The right control  76  includes a button switch  80 , a rocker switch  82 , and a trigger switch  81  thereon. The right control  76  also includes a trigger switch  96  and a potentiometer  84 . 
     FIG. 3  is a schematic drawing showing the interconnection of the various parts. A rechargeable battery  88  is mounted on the left handle  66  and is electrically connected to switch  96 , potentiometer  84  and vibrator  52 . Potentiometer  84  is rotatably adjustable to change the intensity of the vibrations caused by vibrator mechanism  52 . If the slump of the concrete is drier or lower the potentiometer  84  is turned to cause the vibrator to vibrate with more intensity and higher frequency. If the slump of the concrete is wetter or higher than the potentiometer  84  is set so as to reduce the frequency and intensity of the vibrator  52 . Switch  96  turns the vibrator  52  on or off and the vibrator  52  will not operate unless switch  96  is on. 
   Battery  88  is also connected to tilt control box  86 . Trigger switch  81  actuates the control box  86  and switch  80  acts through control box  86  to actuate or deactuate receiver  58 . Rocker switch  82  is a three position override switch. In its neutral position shown in  FIG. 3  it does not override actuator  38  and lets the control box  86  automatically control the actuation of actuator  38 . In this automatic mode receiver  58  sends a signal to control box  86  whether the receiver  58  is above, below, or even with the horizontal laser beam  60 . If the receiver  58  is below the laser beam  50  it sends a signal to control box  86  to actuate tilt actuator  38  to cause the screed plate or blade  12  to move to the position of  FIG. 2 . Conversely, if the receiver is above the laser beam  60  it sends a signal to control box  86  to cause actuator  38  to move to the position of  FIG. 2B . Rocker switch  82  can be used to override to automatic control provided by control box  86  and cause the screed plate or blade  12  to move to the positions shown in  FIGS. 2A and 2B  as the operator chooses. Unless trigger switch  81  is in its on position the control box and the actuator  38  cannot be actuated. 
   Rechargeable battery  88  drives the vibrator  52 , the receiver  58 , the control box  86  and the tilt actuator  38 . 
   Referring again to  FIG. 1 , a support leg  90  is pivotally mounted about a leg pivot  94  and includes a lower end  92  which rests on the surface supporting the screed plate  12 . During the operation of the device with an operator grasping the handles  64 ,  66 , the support leg  90  is pivoted to a position approximately parallel to the handle  66  so that it is out of the way. 
   A turn buckle  100  is connected at one end to the handle  66  and is connected at the other end to a turn buckle link  102  which in turn is connected to leveling angle  62 . The turn buckle  100  may be turned to cause the upstanding member  56  to be substantially vertical in accommodation to the particular height of the operator operating the screed device  10 . For taller operators the turn buckle can be adjusted to accommodate the handle ends  72  being at a higher level and for a shorter operator the turn buckle  100  can be correspondingly changed to accommodate the shorter operator. Once the turn buckle  100  is adjusted for a particular operator the upstanding member  56  will be substantially vertical. 
   In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstance may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.