Patent Publication Number: US-8528881-B2

Title: Pan puller for removing forming pans between joists of a concrete floor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND 
     The disclosure relates to concrete joist systems created with standard forming pans. More particularly, the disclosure relates an apparatus for stripping the pans from the concrete joist system once formed. 
     Pan joist construction refers to a method of constructing a floor system having a ribbed slab using standard forming pans. During construction, a frame for the floor is initially installed. The frame includes a plurality of spaced forming pans. Each forming pan functions as a mold for the creation of a void. Each pair of adjacent forming pans enables the formation of a joist therebetween. Concrete is then poured into the frame between and over the forming pans to create a slab with integrally formed joists. After the concrete sets, the frame and forming pans are removed. 
     Typically the forming pans are removed manually. This process involves one or more individuals prying each pan from the ribbed slab using a pry bar, or other similar device. Once freed from the slab, the forming pan is collected for reuse. Because pan removal is performed manually, this process can significantly increase the time required to construct the floor system. Moreover, pan removal is fraught with safety concerns due to the amount of force that must be applied to pry the forming pans loose. 
     Accordingly, there is a need for an apparatus that enables pan removal at a faster rate than that possible using conventional manual methods and with minimal human involvement. 
     SUMMARY OF THE EMBODIMENTS 
     An apparatus for removing a forming pan from a concrete slab having integral joists is disclosed. The apparatus is referred to herein as a pan puller. In some embodiments, the pan puller includes a rotatable wheel having a plurality of teeth adapted to engage and remove the forming pan from the slab due to rotation of the wheel and a basket coupled thereto, the basket adapted to receive and contain the removed forming pan. 
     In some system embodiments for removing the forming pan from the concrete slab, the system includes a forklift powered by a power supply and a pan puller supported thereon. The pan puller includes a motor receiving power from the power supply, a wheel driven to rotate by the motor, the wheel having a plurality of teeth adapted to engage and remove the forming pan from the joint, and a basket configured to receive and contain the removed forming pan. 
     In some method embodiments for removing the forming pan from the concrete slab, the method includes rotating a wheel having a plurality of teeth, engaging the forming pan with at least one of the teeth, and removing the forming pan from the slab. The method may further include positioning a basket proximate the wheel and receiving the removed forming pan in the basket. 
     Thus, embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with conventional methods for stripping forming pans from an installed concrete floor system. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments, and by referring to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of the disclosed embodiments, reference will now be made to the accompanying drawings in which: 
         FIG. 1  is a perspective view of an embodiment of a pan puller in accordance with the principles disclosed herein; 
         FIG. 2  is a schematic side view of the pan puller of  FIG. 1 ; 
         FIG. 3  is a schematic top view of the pan puller of  FIG. 1 ; 
         FIG. 4  is a schematic end view of the pan puller of  FIG. 1 ; 
         FIG. 5  is an enlarged view of the stripper wheel of  FIG. 2 ; and 
         FIG. 6  is a schematic representation of the pan puller of  FIG. 1  stripping a forming pan from a concrete floor system. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS 
     The following description is directed to exemplary embodiments of a pan puller and associated methods. The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. One skilled in the art will understand that the following description has broad application, and that the discussion is meant only to be exemplary of the described embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment. 
     Certain terms are used throughout the following description and the claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. Moreover, the drawing figures are not necessarily to scale. Certain features and components described herein may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in interest of clarity and conciseness. 
     In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections. Further, the terms “axial” and “axially” generally mean along or parallel to a central or longitudinal axis, while the terms “radial” and “radially” generally mean perpendicular to the central or longitudinal axis. 
     Referring now to  FIG. 1 , there is shown a perspective view of a pan puller  100  in accordance with the principles disclosed herein. As will be described, pan puller  100  enables removal and containment of forming pans used to create concrete a concrete slab floor with integral joists. Pan puller  100  includes a pan stripper assembly  105 , a pan catcher assembly  110 , and a stripper support assembly  115 . 
     In some embodiments, including the illustrated embodiment, pan puller  100  further includes two forklift guides  120 . As shown, forklift guides  120  extend substantially parallel to one another below stripper support assembly  115  and pan catcher assembly  110 . Each forklift guide  120  is tubular, enabling the fork of a forklift to be received therein. With forks inserted into guides  120 , pan puller  100  may then be moved by the forklift to a desired location and supported while pan puller  100  is utilized to remove forming pans from the ribbed slab. 
     Pan stripper assembly  105  enables removal of the forming pans from the ribbed slab. As shown in  FIGS. 2 through 4 , pan stripper assembly  105  includes a stripper wheel  125 , a wheel shaft  130 , two bearings  135 , a gearbox  140 , and a motor  145 . Wheel shaft  130  is cylindrical in shape and has two opposing ends, each end supported by one bearing  135 . Shaft  130  is rotatable relative to bearings  135  in a direction  155 , best illustrated in  FIG. 2 . Stripper wheel  125  is coupled about shaft  130  and rotatable with shaft  130 . 
     Motor  145  is an electric DC motor and preferably powered by the same source which powers the forklift supporting pan puller  100 . Gearbox  140  is coupled mechanically between motor  145  and shaft  130  and electrically coupled to motor  145 . The combination of motor  145  and gearbox  140  provides desired levels of rotational speed and torque to shaft  130 , and thus stripper wheel  125 . In some embodiments, the combination of motor  145  and gearbox  140  rotates shaft  130  at a speed of approximately 5 revolutions per minute (RPM) with up to 1,400 ft-lbs of torque. Further, in some embodiments, motor  145  is a 12 volt DC motor manufactured by Baldor Electric Company, headquartered at 5711 R. S. Boreham, Jr. Street, Fort Smith, Ark. 72901. Also, gearbox  140  is a K Series, Right Angle Helical/Bevel gear drive manufactured by Stober Drives Inc., a division of Stober Antriebstechnik GmbH, headquartered in Pforzhiem, Germany. 
     As best viewed in  FIG. 5 , stripper wheel  125  has a circular body  160  with an outer surface  165  and a plurality of teeth  170  extending therefrom. In some embodiments, body  160  and teeth  170  are integral, formed from a single piece of material by methods such as but not limited to laser cutting. Each tooth  170  has a front face  175 , a rear face  180 , both faces  175 ,  180  defined with respect to rotation direction  155 , and a tip  185  located therebetween. The angle  190  between outer surface  165  of body  160  and front face  175  of tooth  170  is preferably acute. This enables tips  185  of teeth  170  to engage or “catch” an edge of an installed forming pan when wheel stripper  125  rotates in direction  155 . Once engaged with, or caught on, the forming pan, stripper wheel  125  has sufficient torque to pull and remove the forming pan from the ribbed slab. 
     Referring again to  FIGS. 2 through 4 , pan catch assembly  110  receives and contains the forming pan once removed by pan stripper assembly  105 . In the illustrated embodiment, pan catch assembly  110  includes a pan  195  with a plurality of vertical and angled posts  200 ,  205 , respectively, coupled thereto. Pan  195  includes a plurality of horizontally-extending posts  210  coupled between two posts  215  extending normally thereto. Posts  210  are positioned relative to each other such that the spacing  220  between each pair of adjacent posts  210 , best viewed in  FIG. 3 , is too small to allow a forming pan to pass therebetween, thus preventing the forming pans from falling through pan  195  and posing a safety hazard during operation of pan puller  100 . 
     Vertical posts  200  are coupled to the outermost posts  210  of pan  195  and extend substantially normally relative to the outermost posts  210 . Angled posts  205  are coupled to the post  215  distal pan stripper assembly  105  and extend at an angle  225  relative to a horizontal plane  230 . Pan  195  with posts  200 ,  205  coupled thereto form a basket  240  with pan  195  functioning as the base or bottom of basket  240  and posts  200 ,  205  defining sides of basket  240  extending upward its base. Basket  240  receives and contains the forming pans once removed from the ribbed slab by pan stripper assembly  105 . Further, each post  205  has a lower end, or foot,  235  that enables pan puller  100  to be positioned on the ground in a stable orientation when not in use. 
     Stripper support assembly  115  supports pan stripper assembly  105  such that wheel stripper  125  is positioned at the proper location relative to pan catch assembly  110 . In the illustrated embodiment, stripper support assembly  115  includes two shaft support members  245 , a motor support member  250 , three coupling members  255 ,  260 , and at least four supports or feet  265 . Shaft support members  245  extend substantially vertically, each support member  245  coupled to and supporting one bearing  135  and an end of shaft  130  inserted therein. Together support members  245  support bearings  135 , shaft  130 , and stripper wheel  125 . Similarly, motor support member  250  extends substantially vertically to support motor  145  and gearbox  140  with gearbox  140  coupled to the upper end of member  250  and motor  145  suspended below gearbox  140 , as shown. 
     Coupling members  255 ,  260  enable coupling of support members  240 ,  245  to basket  240  such that basket  240  is able to receive forming pans removed by stripper wheel  125 . In this embodiment, coupling members  255  extend substantially parallel to each other and are coupled between the lower end of one shaft support member  245  and basket  240 . Member  260  extends substantially normally between members  255  and is coupled to the lower end of motor support member  250 . 
     When present, forklift guides  120  are coupled to coupling members  255  such that guides  120  extend substantially normally to members  255  and straddle the center of gravity of pan puller  100 . This enables pan puller  100  to remain in a stable orientation when raised by a forklift. Feet  265  are coupled to members  255  and extend vertically downward therefrom. Feet  265  of stripper support assembly  115  and feet  235  of pan catcher assembly  110  enable pan puller  100  to be positioned on the ground in a stable and substantially horizontal orientation when not in use. 
     During operation of pan puller  100 , stripper wheel  125  experiences loads due to engagement of teeth  170  with the forming pans. The loads are transferred through stripper wheel  125  to other components of pan puller  100 . To enable pan puller  100  to withstand these loads without excessive deformation and remain both stable and operational, pan puller  100  further includes a plurality of flanges  270  and bracing  275  that provide additional support to components previously described. 
     In the illustrated embodiment, two flanges  270  are coupled between motor support member  250  and coupling member  260  to strengthen the connection between members  250 ,  260  and prevent excessive deformation of member  250  relative to member  260  due to loads from wheel stripper  125 . Additional flanges  270  are similarly coupled between shaft support members  245  and coupling members  255  and between motor support member  250  and gearbox  140 . Bracing  275 , best viewed in  FIG. 4 , is coupled between shaft support members  245  just below motor  145  to further stabilize members  245 . 
     Referring finally to  FIG. 6 , prior to operation of pan puller  100 , forks of a forklift  300 , represented schematically, are inserted into forklift guides  120  of pan puller  100 , and motor  145  is connected to a power source. Preferably, the power source is that also powering forklift  300 . In some embodiments, the forklift power supply is a battery located on forklift  300 . Thus, the battery powers both forklift  300  and pan puller  100 . Pan puller  100  is then moved by forklift  300  to a desired position proximate a forming pan  305  to be removed from a ribbed slab  310  of a floor system  315 . 
     When in the desired position, pan puller  100  is actuated to rotate stripper wheel  125 . As stripper wheel  125  rotates, forklift  300  is moved closer to forming pan  305  to enable teeth  170  ( FIG. 5 ) of stripper wheel  125  to engage or “catch” an edge  320  of forming pan  305  and pull pan  305  from ribbed slab  310 . Once free of slab  310 , forming pan  305  falls into basket  240  where it remains until forming pan  305  may be removed from basket  240  for storage and/or reuse. After forming pan  305  is safely received in basket  240 , pan puller  100  is repositioned beneath the next forming pan to be removed, and the removal process is repeated. When basket  240  is full, pan puller  100  may be relocated to enable basket  240  to be emptied. 
     While various embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings herein. The embodiments herein are exemplary only, and are not limiting. Many variations and modifications of the apparatus disclosed herein are possible and within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.