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This is a provisional application No. 60/079,610, filed Mar. 27, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     In the renovation and repair of industrial buildings, such as factories and warehouses, it is often necessary to remove existing floor coverings. These floor coverings can be of a great variety of materials, such as rugs, wood, tile, etc. which are secured to a cement floor by high strength adhesive. The removal of such floor coverings is a labor intensive and difficult task. The machines currently available take the form of hand or motor driven scrapers which push a heavy duty scraping blade over the floor to raise the floor covering. 
     A machine of this type which is designed specifically for tile removal is described in U.S. Pat. No. 5,641,206. The machine of the &#39;206 patent employs an hydraulic cylinder to raise and lower the blade into engagement with the floor. The force distribution requires supplemental weights at the front and back of the machine to increase the force response of the blade and to insure proper traction on the rear wheel. Such machines do not perform efficiently, thereby requiring repetitive passes over the floor. 
     It is the purpose of this invention to improve the performance of a tile scrapping machine and the overall operation of such machines. 
     SUMMARY OF THE INVENTION 
     A machine is designed having a frame articulated along a pivot axis displaced a short distance forward of the wheel axis. The frame consists of a main body and a rear portion. The main body is constructed with an integral blade mounting bracket welded to its forward end. A forward support wheel is mounted for vertical movement on the main body just rearward of the blade. An hydraulic piston is operatively connected to the support wheel to retract the wheel during operation of the scrapper. 
     The rear frame portion is constructed with a pair of flanges having means to attach the axle for the rear wheels. The flanges extend a short distance both forward and rearward of the axis of the wheels. The main body is pivotally attached to the rear flanges by means of a horizontally extending cylindrical bar just forward of the drive wheel axis. A transverse beam connects the two flanges just behind the axis of the drive wheels. In order to adjust the angle of the blade a second hydraulic cylinder is connected to the transverse beam to exert a moment force on the rear frame portion to pivot the flanges about the wheel axis and thereby raise the rear of the main body. 
     The main body encloses a reservoir for hydraulic fluid which is pumped to independent drive pumps operatively connected to each wheel. In addition the same fluid is used to operate the front wheel retraction cylinder and the rear blade height adjustment cylinder. A drive pressure is obtained from main drive pumps which may be operated either by a piston engine powered by propane or an electrical motor each being mounted on the main body. 
    
    
     DESCRIPTION OF THE DRAWING 
     The invention of this application is described in more detail below with reference to the Drawing in which: 
     FIG. 1 is a front perspective view of a machine employing the features of this invention; 
     FIG. 2 is a rear perspective view of a machine employing the features of this invention; and 
     FIG. 3 is an exploded perspective view of the frame of this invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the figures, the machine of this invention includes a high strength blade element  6  mounted for engagement with the floor to scrape and remove surface materials. The machine consists of a frame  1  constructed in two primary sections, a main body  2  and a rear flange assembly  21 . Body  2  extends forward from the wheels  22  in a substantially horizontal attitude in the non-operational condition, i.e., blade  6  raised above the floor. Body  2  is comprised of a rear pivot support extension  16 , a forward mounting beam  3  and a blade mounting bracket  4 . The assembly of elements comprising the body  2  are welded together to form a rigid support element for the machine. A heavy duty scrapper blade  6  is mounted on the bracket  4  through an optional wedge  5 . 
     A support castor  8  is mounted on an angle iron  7  which in turn is mounted on the actuating shaft  10  of an hydraulic cylinder  9 . The castor support assembly is therefore retractable upon operation of cylinder  9 . The body  2  encloses an interior reservoir  23  which is filled with hydraulic fluid through spout  12  which is closed by cap  13 . 
     The rear flange assembly  21  consists of side flanges  17  connected by transverse beam  18  to form a support frame for the axle and wheels  22 . The transverse beam  18  is welded at its ends to each of the flanges  17  to form an integral assembly. The side flanges  17  extend, both forward and rearward, a short distance from the wheel axle  20 . At their forward end, the flanges are pivotally connected to a pivot bar  40 , which is pivotally mounted on the support extensions  16  of the body  2 . In this manner the assembly of body  2  and rear frame  21  form an articulated assembly which pivot about a horizontal axis B just forward of the rotational axis A of the drive wheels  22 , as shown by arrows  37  and  38 . 
     A vertical frame member  11  extends upward from the body  2  to support a variety of machine elements described below. An hydraulic cylinder  14  having an actuating shaft  15  is connected between the body  2  and the rear frame  21  at the vertical frame member  11  and the transverse beam  18 , respectively. Actuation of the cylinder  14  will extend the actuating shaft  15 , thereby exerting a moment force on the rear of frame  21 , as illustrated by arrow  39 . This force will tend to raise the forward portion of frame  21  with the rear portion of the body  2  and adjust the operational angle Φ of the blade  6 . 
     As shown in FIGS. 1 and 2 each of the pair of wheels  22  are independently driven by drive pumps  24 . The drive pumps  24  are supplied by main pressure pumps  25  and  26 . Pump  25  is driven by an electrical motor  27  mounted on vertical frame  11 . Pump  26  is driven by piston engine  28 . An electrical supply is connected to electric motor  27  through conduit  29  contained on reel  30 . Reel  30  is mounted on a retractable extension  31  of the vertical frame  11 . A source of propane, tank  35 , is mounted on the vertical frame  11  to power the piston engine  26 . 
     The hydraulic components are connected through a system of conduits  32  and controlled by a series of control valves  33  operated by manual levers  34 . 
     The operator sits on the seat  36  mounted on the vertical frame  11  within easy reach of the manual levers  34 . The height of the seat is adjusted to provide the operator with a clear view of the blade  6  during operation. 
     In operation the source of power is selected, either electrical or propane, and energized. Through the actuation of cylinder  9 , the wheel  8  is retracted to allow the full weight of the machine to be supported on blade  6 . The blade  6  will engage the surface of the floor along an angle Φ and exert a force indicated by force vector F as the drive wheels  22  are driven forward. The angle Φ of force vector F is adjustable through the actuation of cylinder  14 . Depending on the difficulty of the removal operation, the width of the blade may be varied, a narrower blade being used for more difficult tasks. Through the independent drive mechanisms, the rotation of the wheels may be relatively adjusted to steer the machine across the work area.

Summary:
A machine for scrapping surface materials from a floor having an articulated structure which allows the adjustment of the angle of the scraper blade by pivot motion of the main body element. A front wheel assembly is retractable to allow the blade to support the machine. A dual power mode is also provided.