Patent Publication Number: US-2007116520-A1

Title: Vibrating device for screeding machine

Description:
CROSS REFERENCE TO RELATED APPLICATION  
      The present application claims the benefit of U.S. provisional application Ser. No. 60/738,091, filed Nov. 18, 2005, which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to screeding devices for screeding and finishing a surface of loose and/or plastic material such as of uncured concrete, sand, dirt, combinations thereof or the like and, more particularly, to a screeding device having a screed head assembly which includes a vibrating device.  
     BACKGROUND OF THE INVENTION  
      It is known to provide a screed head assembly which includes a plow, auger and vibrating device and which is operable to establish a grade and substantially compact, smooth and/or finish the surface of loose, plastic material such as uncured concrete. The vibrating device typically includes a generally horizontal beam for engaging the concrete surface, and a generally horizontal shaft extending along the beam. The shaft includes eccentric weights or discs spaced therealong. Rotational driving of the shaft thus imparts rotation of the eccentric weights which, in turn, causes the beam to vibrate to compact and screed the concrete surface as the screed head assembly is moved over and along the concrete surface.  
      Typically, the eccentric weights are rotated in response to a drive motor that rotatably drives a horizontal drive shaft that is mounted along the vibrating member. The horizontal drive shaft or shafts is/are rotatably driven by the drive motor and function to rotatably drive the eccentric weights. Such horizontal drive shafts are supported and mounted along the vibrating member via a plurality of bearings and mounts to rotatably support the shaft or shafts at multiple locations along the vibrating members.  
     SUMMARY OF THE INVENTION  
      The present invention is intended to provide a screed head assembly for a screeding device or machine which includes a plow, an auger and a vibrating device. The vibrating device includes a drive motor and drive system that operate to rotate a pair of eccentric discs at or toward or near each end of a vibrating member, so as to vibrate the vibrating member to compact and smooth the concrete surface. The drive system includes drive pulleys and drive belts that operate to rotate the eccentric discs in response to rotational driving by the drive motor.  
      According to an aspect of the present invention, a vibrating device for a screed head assembly mountable to a screeding device includes a vibrating member and a vibrating system. The vibrating member comprises a unitary or integrally formed elongated member having upper and lower screeding surfaces and a vertical portion extending therebetween. The vertical portion defines a hollow cavity therealong. The vibrating system is mounted to the vertical portion of the vibrating member and operates to vibrate the vibrating member to screed the concrete surface when the lower screeding surface engages the concrete surface.  
      The vibrating member may comprise an extruded vibrating member, such as extruded of aluminum or other suitable material. The upper and lower screeding surfaces may be formed to be substantially similar so that the vibrating member may be flipped over to use the initially upper screeding surface to engage the concrete surface. Optionally, the hollow cavity may be filled with an insulating element.  
      According to another aspect of the present invention, a vibrating device for a screed head assembly mountable to a screeding device includes a vibrating member and a vibrating system. The vibrating member includes a generally planar lower surface for engaging a surface of uncured concrete, dirt, sand, gravel or the like, and a generally vertical portion extending upwardly from the lower surface. The generally vertical portion extends longitudinally along the vibrating member. The vibrating system is operable to vibrate the vibrating member to compact and smooth the concrete surface. The vibrating system includes a drive motor operable to rotatably drive at least one drive pulley which, in turn, drives a drive band or belt to rotate at least one eccentric element rotatably mounted to the vibrating member. Rotation of the eccentric element or elements imparts a vibration to the vibrating member.  
      Optionally, the eccentric element comprises a pair of eccentric elements spaced along the vibrating member. Optionally, the eccentric element comprises a pair of eccentric discs mounted at a rotatable shaft. One of the eccentric discs may be fixedly mounted to the shaft and the other of the eccentric discs may be adjustably positioned about the shaft relative to the first eccentric disc. The eccentric discs may be selectively oriented to selectively set a degree of vibration of the vibrating element.  
      Therefore, the present invention provides a vibrating device for a screed head assembly that includes an extruded vibrating member and a pulley and belt drive system. The extruded vibrating member may provide a low cost vibrating member that may be flipped or reversed to provide an increased life cycle of the vibrating member as one surface or edge becomes worn. The extruded vibrating member may include a hollow cavity therealong, and the cavity may be substantially filled with an insulating material or element to reduce noise during operation of the vibrating device. The drive system provides rotational driving of eccentric elements to vibrate the vibrating member, while providing a mounting arrangement that has reduced bearings and mounts as compared to known horizontal shaft vibrating systems.  
      These and other objects, purposes, advantages and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a screed device or machine having a screed head assembly and vibrating device in accordance with the present invention;  
       FIG. 2  is a perspective view of the vibrating device suitable for use with the screed head assembly of  FIG. 1 ;  
       FIG. 3  is another perspective view of the vibrating device of  FIG. 2 ;  
       FIG. 4  is another perspective view of the vibrating device of  FIGS. 2 and 3 , taken generally at an end of the vibrating device;  
       FIG. 5  is another perspective view of the vibrating device of  FIGS. 2-4 , taken generally at the same end as in  FIG. 4 ;  
       FIG. 6  is an end elevation of a portion of the vibrating device of the present invention, showing the drive belts and pulleys of the drive system of the present invention;  
       FIG. 7  is an enlarged perspective view of the drive system of the vibrating device of  FIG. 3 ;  
       FIG. 8  is an enlarged end elevation of the drive system shown in  FIG. 6 ; and  
       FIG. 9  is an end elevation of the eccentric discs suitable for use with the vibrating device of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring now to the drawings and the illustrative embodiments depicted therein, a screeding device or machine  10  includes a wheeled base unit  12  and an extendable or telescoping boom assembly  14  which extends from base unit  12  ( FIG. 1 ). A screed head assembly  16  is adjustably mounted at an outer end  14   a  of extendable boom  14 , as discussed below. Wheeled base unit  12  is movable via wheels  26 , preferably having pneumatic tires  28  formed from rubber or other materials thereon, and is positionable adjacent to an area of uncured concrete (or other material) to be processed, worked, compacted, vibrated, smoothed and/or screeded by screed head assembly  16 . In the illustrated embodiment, screed head assembly  16  includes an auger device or assembly  18 , a plow  20  positioned forwardly of auger device  18 , and a vibrating device  22  positioned rearwardly of auger device  18 . Plow  20  and auger device  18  function to establish the grade of the uncured concrete surface, while vibrating device  22  compacts and smoothes the uncured concrete surface as screed head assembly  16  is moved over the uncured concrete surface, as discussed below. Although described as being suitable for processing an uncured concrete surface, the present invention is equally suitable for processing surfaces of other materials, such as sand, dirt, gravel or the like, without affecting the scope of the present invention.  
      Wheeled base unit  12  includes a lower support frame  24  having front and rear propulsion support axles, each of which may provide both propulsion and steering capability of the tired wheels  26 ,  28 . An upper frame  30  of base unit  12  may be rotatable relative to lower frame  24  and may include an operator support platform or control platform  32 . Wheels  26  may be individually driven or powered by hydraulic motors (not shown) or other means for independently driving the wheels of base unit  12 , without affecting the scope of the present invention. Wheeled base unit  12  and boom assembly  14  of screeding device  10  may utilize principles disclosed in U.S. Pat. Nos. 4,930,935; 6,183,160; 6,152,647; and/or 6,129,481, which are hereby incorporated herein by reference.  
      The concrete screeding machine may comprise any type of concrete screeding device or machine, such as a LASER SCREED™ screeding machine as commercially available from Somero Enterprises, Inc. of Houghton, Mich., or other types of suitable concrete screeding devices or machines, without affecting the scope of the present invention. For example, the screeding machine may comprise a screeding machine of the types disclosed in U.S. Pat. Nos. 4,655,633; 4,930,935; and 6,227,761, which are hereby incorporated herein by reference. In the illustrated embodiment, the extendable and retractable boom  14  extends and retracts relative to the wheeled base unit  12 , and is extendable and retractable to move screed head assembly  16  over and along a targeted concrete surface, while the screed head assembly  16  is vertically adjustable relative to the boom  14 .  
      The screed head assembly  16  may be adjustably positioned such that the auger  18  is at a desired grade via a pair of actuators or hydraulic cylinders  34 , one at or near each end of the screed head assembly. The actuators  34  may be operable to raise and lower the screed head assembly in response to an automatic elevation control system, such as a control system utilizing laser beacon receivers  36  and a laser reference plane generator (not shown), which is typically mounted externally of screeding machine  10  on a tripod or another fixed location. The elevation of the plow, vibrating assembly and auger assembly may thus be adjustable relative to a cross member support in response to the laser plane system, such as by utilizing aspects of the screeding devices described in U.S. Pat. Nos. 4,655,633; 4,930,935; and 6,227,761, which are hereby incorporated herein by reference. Optionally, the laser receivers may be replaced with at least one three dimensional tracking target (not shown) and one sonic height sensor (not shown) for use with an automatic three dimensional profiler system commercially available from Somero Enterprises of Houghton, Mich., and such as disclosed in U.S. Pat. No. 6,227,761, issued May 8, 2001 to Kieranen et al. for APPARATUS AND METHOD FOR THREE DIMENSIONAL CONTOURING, which is hereby incorporated herein by reference.  
      Screed head assembly  16  includes vibrating device  22  positioned rearwardly of auger device  18  and plow  20 . As shown in  FIGS. 2-5 , vibrating device  22  includes an elongated, generally I-shaped vibrating beam or member  38 , which includes a generally flat or planar base or lower portion or screeding surface  38   a , a similarly formed, generally flat upper portion or screeding surface  38   b  and a generally vertical portion or web  38   c  extending therebetween. Lower portion  38   a  may include an upwardly turned front or leading lip  38   d  along a forward or leading edge thereof to limit or substantially preclude vibrating member  38  from cutting into the uncured concrete surface as screed head assembly  16  is moved over the uncured concrete surface.  
      In the illustrated embodiment, the lower and upper portions  38   a ,  38   b  of vibrating member  38  are substantially similar so that the vibrating member  38  is formed to be reversible. Thus, if the vibrating member were to be flipped 180 degrees about its longitudinal axis, the vibrating member could be used with the initially upper portion  38   b  engaging the concrete surface (and with a curved lip  38   e  at its forward or leading edge when so positioned). Such a formation allows the vibrating member to be flipped to use the other side or portion, such as in situations where the lower portion  38   a  becomes worn, and thus may extend the life cycle of the vibrating member.  
      As best shown in  FIGS. 4 and 5 , vibrating member  38  comprises a generally hollow member with a central cavity along the member and between the generally vertical and spaced apart walls  39   a ,  39   b  of the vertical portion  38   c . Preferably, the vibrating member comprises an integral member or unitary member, which is unitarily formed via a forming process. For example, the vibrating member may be extruded to form the hollow elongated member with the upper and lower portions being substantially similar to one another and reversed relative to one another. The material selected for the extruded vibrating member may comprise any suitable material, such as aluminum or the like, without affecting the scope of the present invention.  
      As shown in  FIGS. 2-5 , vibrating device  22  includes a pair of rubber isolators or mounts  40 , with a mounting element  40   a  protruding therefrom, for attaching or mounting the vibrating device to the screed head assembly. As best shown in  FIGS. 4 and 5 , isolators  40  and mounting element  40   a  (such as a threaded stud or the like) may be secured to a mounting or attaching plate  42 , which may be secured between the vertical walls  39   a ,  39   b  via spacer elements  42   a  (such as substantially rigid aluminum spacers or the like) and associated fasteners or the like. The rubber isolator may protrude from the plate  42  and through an opening or aperture  44  in one of the vertical walls  39   a  for engagement with the screed head assembly. As can be seen in  FIGS. 4 and 5 , the vibrating member  38  may be formed with the apertures  44  through both of the vertical walls  39   a ,  39   b , so that the isolators may protrude through either aperture depending on the orientation or direction of the vibrating member  38 .  
      Vibrating device  22  also includes a pair of spaced apart vibrator mounting brackets or arms or members  46 , which are adjustably secured to the screed head assembly, such as to an auger support beam or the like and toward opposite ends thereof. The vibrator mounting arms  46  may be pivotally mounted at the upper portion  38   b  of vibrating member  38 , and may be pivotally mounted at the screed head assembly. Vibrating member  38  may include a pair of brackets  48  attached to upper portion  38   b . The vibrator mounting arms  46  may be mounted to the respective brackets  48 , such as generally L-shaped brackets as shown in  FIGS. 2 and 3 , via rubber vibration isolators or mounts  46   a  to minimize vibration from the vibrating member  38  back to mounting arms  46  and the auger support beam and screed head assembly. Likewise, the mounting arms  46  may be mounted to the auger support beam via rubber vibration isolators or mounts  46   b  to reduce vibration at the screed head assembly during operation of the vibrating device. In the illustrated embodiment, the mounting arms  46  are adjustable elements, such as threaded turnbuckles or the like, so that the arms may be adjusted in length to adjust the angle or orientation of the vibrating member  38  relative to the screed head assembly to set a desired pitch or attack angle of the vibrating member.  
      Vibrating device  22  includes a vibrating system or drive system  50 , which is operable to vibrate the vibrating member  38  to compact and smooth and screed the concrete surface when the vibrating member engages the concrete surface and while the screed head assembly is moved along the concrete surface. Drive system  50  includes a rotational driving motor  52 , such as a hydraulic motor or the like, and a drive assembly  54 , which functions to rotate a pair of eccentric elements  56  in response to rotational driving by the drive motor  52 , as discussed below. As shown in  FIGS. 2 and 4 , drive motor  52  is mounted to vertical wall  39   b  (the rearward or trailing wall when in use) of vibrating member  38 . Drive motor  52  includes a drive shaft that extends from the motor and through the vertical portion  38   c  of vibrating member to couple with or connect to a drive pulley  54   a  of drive assembly  54 , which is attached or mounted at the other vertical wall  39   a  (the forward or leading wall when in use) of vibrating member  38 .  
      Drive assembly  54  includes drive pulley  54   a , a pair of idler pulleys  54   b ,  54   c  and a guide or tensioning idler pulley  54   d  rotatably mounted at a generally central location along vertical wall  39   a  of vibrating member  38 . As best shown in  FIGS. 5-8 , a drive belt  58  is reeved around the drive pulleys  54   a ,  54   b ,  54   c ,  54   d  and around wheels or pulleys  60  that are coupled with the respective eccentric weights or discs or elements  56  at or near the opposite end or outer regions of the vibrating member. The belt may comprise any type of drive belt or chain or the like, and may include teeth or ridges along a surface thereof for enhanced gripping and engagement with the pulleys, while remaining within the spirit and scope of the present invention. Thus, rotational driving of drive pulley  54   a  via operation of drive motor  52  functions to drive the belt  58  around the pulleys  54   b ,  54   c ,  54   d  and  60  to rotate the eccentric elements  56  about their generally horizontal axes so as to impart a vibration to the vibrating member  38 .  
      As best seen in  FIGS. 6-8 , drive pulley  54   a  and idler pulleys  54   b  and  54   d  are rotatably mounted to a mounting bracket  62  that is attached to vertical wall  39   a  of vibrating member  38 . The bracket  62  thus may be readily attached to the vertical wall  39   a  (such as via suitable fasteners or the like) and the pulleys may be mounted at the bracket, thereby easing the assembly process of the pulleys to the vibrating member. The drive pulley  54   a  and idler pulleys  54   b ,  54   d  thus may be substantially fixed relative to one another by their respective mounting to the mounting bracket  62 , which, in turn, is fixedly attached to vibrating member  38 . As can be seen in  FIGS. 6-8 , however, idler pulley  54   c  may be adjustably mounted to vibrating member  38  to allow for adjustment of the tension in the drive belt  58 .  
      In the illustrated embodiment, idler pulley  54   c  is rotatably mounted to a mounting bracket  64 , which is pivotably or adjustably mounted to vertical wall  39   a  of vibrating member  38 . The bracket  64  is pivotable about one fastener  64   a , and includes an arcuate slot  64   b  for slidably or movably receiving another fastener  64   c  therethrough, so as to allow for pivotal movement of the bracket  64  when the fasteners are loosened a sufficient amount. As can be seen in  FIG. 8 , pivotal movement of the bracket  64  about fastener  64   a  in the counter-clockwise direction would increase the tension in the belt  58 , while pivotal movement about fastener  64   a  in the opposite direction would decrease the tension in the belt  58 . When the bracket is positioned so that the pulley  54   c  provides the desired tension in the belt  58 , the fasteners  64   a ,  64   c  may be substantially tightened to substantially retain the bracket and pulley in the desired orientation. The fasteners may be tightened or secured from the other side of the vibrating member, such as via accessing the fasteners through apertures  66   a  ( FIG. 2 ) in the wall  39   b  of vibrating member  38 , so that the bracket  64  (and thus the idler pulley  54   c ) may be secured relative to the vibrating member without having to remove the idler pulley  54   c  from the bracket  64 . Similarly, the bracket  62  for the fixed pulleys may also be attached and secured via fasteners that are accessible through apertures  66   b  in wall  39   b  of vibrating member  38 .  
      As shown in  FIGS. 2, 4  and  9 , eccentric elements  56  may be rotatably mounted to the vertical wall  39   b  of vibrating member  38  and longitudinally spaced from the center of the vibrating member. Desirably, and as shown in  FIG. 2 , the eccentric elements  56  may be positioned generally at the mid-points between the drive motor  52  or drive assembly  54  and the respective outer ends of the vibrating member  38 , in order to provide substantially uniform vibration along the entire length of the vibrating member. In the illustrated embodiment, each eccentric element  56  includes a pair of discs  68 ,  70 , which are attached to a rotatable shaft  60   a  that rotates in response to rotation of the respective pulley  60 . The shaft  60   a  is attached to the discs  68 ,  70  at a location off-center or remote from the centers of the discs, such that rotation of the shaft  60   a  causes the discs to rotate about an eccentric axis and thus to impart a vibration to the vibrating member.  
      Optionally, and as shown in  FIG. 9 , the discs  68 ,  70  may be adjustable relative to one another to adjust the degree of vibration imparted by the rotation of the discs  68 ,  70 . For example, one of the discs, such as disc  68  of the illustrated embodiment, may be fixedly attached to the shaft  60   a , while the other disc  70  may be rotatable around the shaft and relative to the disc  68  and securable relative to the disc  68  (and thus the shaft  60   a ) when in the desired relative orientation. In the illustrated embodiment, one of the discs  68  includes a plurality of openings or apertures  68   a  formed therethrough, while the other disc  70  may include one or more similar apertures  70   a . A retaining pin  72  or fastener (such as a set screw or the like) may be inserted through aperture  70   a  in disc  70  and into a selected aperture  68   a  in disc  68  to retain or secure the discs  68 ,  70  relative to one another in the desired orientation. Thus, when the discs are oriented so that they are substantially oppositely positioned from one another (such as shown in  FIG. 9 ), the degree of vibration imparted by rotation of the discs is reduced, since the off-center weight of disc  68  is partially or substantially canceled or balanced by the off-center weight of disc  70 . If a greater degree of vibration is desired, the discs may be positioned or adjusted (such as by removing the pin  72  and rotating disc  70  about shaft  60   a ) so that disc  70  is substantially aligned with disc  68 , whereby the degree of vibration imparted by rotation of the discs is increased due to the weight of both discs being at generally the same side or region relative to the axis of rotation of the discs. Thus, the degree of vibration of the vibrating member  38  may be adjusted to a desired level depending on the particular application of the vibrating device  22 .  
      Therefore, the vibrating system or drive system  50  of the vibrating device  22  functions to rotate a pair of eccentric elements to impart the desired degree of vibration to the vibrating member  38 . The belt and pulley drive system provides an efficient system for rotatably driving the eccentric elements, without the need for multiple bearings and the like typically required for horizontal shaft type vibrating systems. The drive system of the present invention thus may provide a system with reduced costs and enhanced assembly over known horizontal shaft systems.  
      Optionally, and desirably, an insulating material or element  74  may be inserted into the hollow cavity of the vibrating member  38 , such as from one of the open ends of the cavity, to substantially fill the cavity to reduce noise during operation of the vibrating device. The insulating element  74  may be inserted from one end (or two insulating elements may be inserted from both ends) of the vibrating member, such as before the isolators  40  and plates  42  and the motor  52  and drive assembly  54  and pulleys  60  and eccentric elements  56  are attached to the vibrating member. The insulating element may then be drilled through to form the apertures for receiving the appropriate fasteners and/or spacers and the like. Optionally, the insulating element may be provided with the apertures already formed therethrough and with the appropriate spacers already received in the apertures, so that the insulating element may be inserted into the end of the vibrating member and positioned so that the apertures and spacers substantially align with the holes in the vertical walls  39   a ,  39   b  of the vibrating member  38 .  
      The insulating element may comprise any suitable insulating material, such as a foam insulating material or the like, and may be substantially rigid to allow for insertion of the insulating element into the cavity and along the vibrating member. Optionally, the insulating element may be a substantially fluid material or foam that is injected into the vibrating member and allowed to cure or substantially solidify within the cavity to insulate the cavity of the vibrating member, without affecting the scope of the present invention. After the insulating element is inserted or otherwise established within the cavity (or at any time if no insulation is established within the cavity), a cap (not shown), such as a molded plastic or polymeric cap or the like, may be attached at each open end of the vibrating member to substantially seal the ends of the vibrating member to limit or substantially preclude intrusion of debris and the like into the cavity of the vibrating member.  
      Therefore, the present invention provides a vibrating device for a screed head assembly that includes an extruded vibrating member and a pulley and belt drive system. The extruded vibrating member may provide a low cost vibrating member that may be flipped or reversed to provide an increased life cycle of the vibrating member as one surface or edge becomes worn. The extruded vibrating member may include a hollow cavity therealong, and the cavity may be substantially filled with an insulating material or element to reduce noise during operation of the vibrating device. The drive system provides rotational driving of eccentric elements to vibrate the vibrating member, while providing a mounting arrangement that has reduced bearings and mounts as compared to known horizontal shaft vibrating systems.  
      Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principle of patent law.