Patent Publication Number: US-2007107179-A1

Title: Device for removing modular concrete forms

Description:
FIELD OF THE INVENTION  
      This invention relates generally to tools used in building construction, and more particularly relates to a device for removing modular forms from underlying rigid concrete.  
     BACKGROUND  
      Stripping plywood style forms from freshly poured walls is problematic in the amount of time needed to break the form loose and remove it from the wall. Using conventional means such as, for example, a carpenters hammer or crowbar, the removal operation takes approximately 20-25 seconds to chip away the concrete from around the form tie, snap off the end of the tie, gouge the claw end of the hammer into the side of the form, pry it up away from the wall slightly, slide the claw end of the hammer between the wall and form to pry against the face of the form to break it free, and then remove the form and place it on the ground.  
      Other drawbacks with the above-mentioned removal operation include excessive time needed to remove inside corner forms, damage to the steel corner forms from having to hammer them to break them free from the wall, damage to the edges of the plywood forms from gouging the claw end of the hammer into it—effectively making the form thicker at the edges so as to make obtaining a smooth transition from the face of one form to the adjacent form difficult. The end results are an uneven surface of the wall when the forms are removed, damage such as gouges and roughness to the face of the forms from prying against it to break it away from the wall (resulting in undesirable blemishes on the finished surface of the wall), and additional expense to the contractor for having to repair the surface of the wall, recondition the face of the forms, or replace the forms prematurely because of excessive wear and tear created by destructive stripping methods.  
      Accordingly, it is a general object of the present invention to overcome the drawbacks of prior tools for removing forms from walls.  
     SUMMARY OF THE INVENTION  
      A device for removing modular forms comprises an elongated shaft having a rearward end and a forward end. A pulling head is coupled to a forward end of the shaft for engaging a form to be removed from a wall. A slide hammer, having a weight of, for example, approximately ten pounds, is slidably coupled to the shaft for generating an impact force to the form via the pulling head to thereby break a bond between the form and the wall. A stop member is located adjacent to the rearward end of the shaft to prevent the slide hammer from moving beyond the stop member toward the rearward end and to create the impact force to the form when the slide hammer strikes the stop member. The device preferably includes a handle coupled to the rearward end of the shaft for the operator to grip with one hand while grasping the slide hammer with the other hand. The handle, for example, can include a pin extending through the shaft in a direction generally perpendicular to a length of the shaft. The slide hammer preferably includes a gripping portion and guard members extending outwardly at longitudinal ends thereof for protecting the hand of the operator while grasping the gripping portion. Preferably, the pulling head defines a bore at a rear portion for being received over the forward end of the shaft.  
      In a first aspect of the present invention, the pulling head includes a forward portion having a forward surface facing in a direction generally away from the shaft. The forward surface defines an open-ended slot for receiving and retaining therein a form lever stud.  
      In a second aspect of the present invention, the pulling head includes a rear portion for being coupled to a forward end of the shaft, and a forward portion including a projection spaced from the forward portion for being received in an opening defined along an edge of a form to be removed. The projection can include a generally flattened pin for engaging flattened slots defined along an edge of SYMONS steel frame forms or other compatible forms. Alternatively, the projection can include a generally cylindrical pin for engaging round holes defined along an edge of DURAND aluminum frame forms or other compatible forms.  
      In a third aspect of the present invention, the pulling head includes a rear portion for being coupled to a forward end of the shaft, and a forward portion including an engagement member defining a channel for being received over an edge of a form. Preferably, the engagement member includes an upper wall, and first and second sidewalls cooperating with one another to define the channel. The pulling head and the shaft can cooperate with one another such that the shaft extends downwardly at an angle relative to the horizontal of, for example, approximately 30 degrees, when the engagement member is in an orientation to engage an upper edge of a form. Alternatively, the pulling head and the shaft can cooperate with one another such that the shaft extends generally horizontally when the engagement member is in an orientation to engage an upper edge of a form. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side view of a device for removing modular forms in accordance with the present invention.  
       FIG. 2  is a front perspective view of the pulling head of the device of  FIG. 1 .  
       FIG. 3  is a back perspective view of the pulling head of the device of  FIG. 1 .  
       FIG. 4  is a side view of a device for removing modular forms in accordance with a second embodiment of the present invention.  
       FIG. 5  is a first end view of a head of the device of  FIG. 4 .  
       FIG. 6  is an enlarged side view of a head of the device of  FIG. 4 .  
       FIG. 7  is a second end view of a head of the device of  FIG. 4   
       FIG. 8  is a top view of a head of the device of  FIG. 4 .  
       FIG. 9  is a side view of a device for removing modular forms in accordance with a third embodiment of the present invention.  
       FIG. 10  is a first end view of a head of the device of  FIG. 9 .  
       FIG. 11  is an enlarged side view of a head of the device of  FIG. 9 .  
       FIG. 12  is a second end view of a head of the device of  FIG. 9   
       FIG. 13  is a top view of a head of the device of  FIG. 9 .  
       FIG. 14  is a side view of a head of a device for removing modular forms in accordance with a fourth embodiment of the present invention.  
       FIG. 15  is a top view of the head of  FIG. 14 .  
       FIG. 16  is a side view of a head of a device for removing modular forms in accordance with a fifth embodiment of the present invention.  
       FIG. 17  is a top view of the head of  FIG. 16 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      With reference to  FIG. 1 , a device for removing modular forms in accordance with the present invention is indicated generally by the reference number  10 . The device  10  includes an elongated shaft  12  having a forward end  14  and a rearward end  16 . A slide hammer  18  is slidably coupled to the shaft  12  for movement back and forth therealong generally between the forward end  14  and the rearward end  16 . The shaft  12  is preferably cylindrical in cross section, but may take other cross-sectional forms such as being square or rectangular without departing from the scope of the present invention. A pulling head  20  is fixedly coupled to the shaft  12  at the forward end  14 . The device  10  may include stop members located adjacent to the forward end  14  and the rearward end  16  of the shaft  12  for preventing the slide hammer  18  from moving along the shaft beyond the stop members as is explained more fully below. The device  10  may also include a handle  26  coupled to the rearward end  16  of the shaft  12  for gripping with one hand while moving the slide hammer  18  with the other hand. As shown in  FIG. 1 , the handle  26  may be in the form of a pin extending outwardly from the shaft  12 , but may take other forms without departing from the scope of the present invention.  
      The slide hammer  18  defines a bore  28  extending therethrough from a first end  30  to a second end  32  for sidably receiving the shaft  12  within the bore. A cross-sectional area or diameter of the bore  28  is slightly larger than that of the shaft  12  for permitting the slide hammer  18  to easily move therealong while limiting lateral play of the slide hammer relative to the shaft. The slide hammer  18  has a substantial weight of, for example, about ten pounds, for generating a large impact force to a form to be removed from a wall. As shown in  FIG. 1 , the slide hammer  18  includes a gripping portion  34  and is preferably interposed between guard members  36 ,  38  extending radially outwardly from the gripping portion for protecting the hand of a user.  
      The pulling head  20  includes a forward portion  40  defining an open-ended slot  42  for engaging a form lever stud. The pulling head  20  also defines an opening  44  at a rear portion  46  for being received over the forward end  14  of the shaft  12 . The pulling head  20  is fixedly coupled to the forward end  14  of the shaft  12  with, for example, retaining lock nuts  48 ,  50  threadably received along the shaft adjacent to each side of the opening  44  of the pulling head. The retaining lock nut  48  located on the shaft  12  adjacent to the forward end  14  thereof and rearwardly of the opening  44  of the pulling head  20  serves as a first stop member to prevent the slide hammer  18  from moving beyond the first stop member toward the forward end  14  of the shaft.  
      A second stop member  52  may be fixedly disposed along the shaft  12  adjacent to the rearward end  16 . The second stop member  52  includes a portion having a larger cross-sectional area or diameter relative to that of the bore  28  of the slide hammer  18  to prevent the slide hammer from moving beyond the second stop member toward the rearward end  16  of the shaft  12 .  
      In operation, the open-ended slot  42  defined by the forward portion  40  of the pulling head  42  slides over and engages a form lever stud of a modular form to be removed from a wall. The pulling head  20  uses the stud as a pulling point to remove the form from the wall, thereby generally eliminating the damage otherwise caused by the gouging of the claw of a conventional hammer or crowbar. A user of the device  10  grasps the gripping portion  34  of the slide hammer  18  with one hand and may grasp the handle  26  with the other hand. The user rapidly moves the slide hammer  18  back and forth along the shaft  12  one or more times as necessary to remove the form from the wall.  
      During each stroke of the slide hammer  18  toward the forward end  14  of the shaft  12 , the slide hammer optionally can be moved far enough along the shaft to impact against the first stop member  48  to suddenly stop the forward movement of the slide hammer. The substantial weight of the slide hammer  18  suddenly stopping against the first stop member  48  generates a large impact force which is propagated forwardly from the shaft  12  to the pulling head  20  to thereby deliver the impact force to the form to be removed. Several such impact forces causes the form to rapidly vibrate relative to the wall so as to weaken and break the bond between the form and the wall.  
      During each stroke of the slide hammer  18  toward the rearward end  16  of the shaft  12 , the impact of the slide hammer against the second stop member  52  suddenly stops the rearward movement of the slide hammer. The substantial weight of the slide hammer  18  suddenly stopping against the second stop member  52  generates a large impact force which is propagated from the shaft  12  to the pulling head  20  to thereby deliver the impact force to the form to be removed. Several such impact forces causes the form to rapidly vibrate relative to the wall so as to weaken and break the bond between the form and the wall. Once the bond is weakened, the operator can pull the form free from the wall by pulling on the handle  26  or by grasping the form with the operator&#39;s hands.  
      Employing a device for removing modular forms in accordance with the present invention significantly reduces the time to remove a form from a wall relative to conventional devices from 20-25 seconds to 6-8 seconds. Eliminating the damage otherwise caused by the use of conventional removal techniques not only decreases the removal time by about 67% to about 75%, but also eliminates the other above-mentioned problems created by the use of conventional removal methods.  
      With reference to  FIGS. 4-8 , a device for removing modular forms in accordance with a second embodiment of the present invention is indicated generally by the reference number  110 . Like elements with the device shown in  FIGS. 1-3  are indicated by like reference numbers preceded by “1”. The device  110  is generally the same as the device  10  except for the pulling head. Accordingly, the device  110  and its operation will be described in detail only with respect to the structure that is different from that of the device  10 .  
      A pulling head  120  is fixedly coupled to a shaft  112  at the forward end  114 . The pulling head  120  includes a neck  121 , an abutment member  123  and a projection  125 . The neck  121  defines a threaded bore  127  for being threadably received on the shaft  112  at a forward end  114  thereof. A first side  129  of the abutment member  123  is coupled to the neck  121 , and a second side  131  of the abutment member, generally facing a direction opposite to that of the first side, is for abutting against a face of a form to be removed. An overhanging member  133  extends outwardly from an upper end  135  of the abutment member  123  in a direction generally away from the second side  131  thereof. As shown in  FIGS. 4 and 6 , the overhanging member  133  extends downwardly at an angle of approximately 30 degrees relative to a plane defined by the upper end  135  of the abutment member  123 , but can lie in the same plane as the upper end or extend outwardly therefrom at other various angles without departing from the scope of the present invention. The projection  125  includes a generally flattened pin  137 , preferably of hardened steel, mounted to and extending outwardly from the overhanging member  133  in a direction generally transverse to a plane defined by the overhanging member.  
      The pulling head  120  of the device  110  is designed for removing SYMONS steel frame forms or other compatible forms that define generally flattened slots along an upper surface thereof. The pin  137  is inserted into a slot in the steel frame of a form along an upper surface thereof. The angle of the overhanging member  133  relative to a central axis of the neck  121  and the shaft  112  attached to the neck permits the pin  137  to be easily inserted in a slot at an upper end of a form that is above the operator&#39;s head, and permits the shaft to extend downwardly at an angle relative to the horizontal from the forward end  114  of the shaft toward the handle end of the shaft in order to permit the operator to move the slide hammer  118  at a comfortable and accessible level.  
      In operation, to remove the first form on a wall, the pin  137  is inserted in a center slot of the steel frame of the form at an upper end thereof. The slide hammer  118  is then moved along the shaft  112  until the slide hammer impacts against the stop member  152 . When the slide hammer  118  impacts the stop member  152  adjacent to the handle end of the device  110 , the impact creates a shock that will help “pop” the form free from the wall. Several such “pops” may be needed to completely remove the form from the wall. Once the first form is removed, the pin  137  is then inserted into the left or right hand slot in the top of the form that is to be removed next. If an operator is stripping forms in a direction to the left, the pin  137  is inserted in the slot furthest to the left. If the operator is stripping forms in a direction to the right, the pin  137  is inserted in the slot furthest to the right. Either way, the device  110  will be located to the side of the form that is in the direction that the operator is stripping the wall.  
      In order to remove inside corners, the pin  137  of the device  110  is inserted onto the top of the corner or into a slot on the side of the corner—preferably the highest or lowest slot. The form ties need to be broken off or bent back away from the corner form in order for the device to be able to completely remove the form from the wall.  
      Although the pulling head  120  of the device  110  is shown and described in an exemplary embodiment by way of example, it should be understood that the pulling head can take other various forms without departing from the scope of the present invention. For example, the neck  121  can be eliminated such that the pulling head  120  is directly or otherwise permanently coupled to the shaft. Moreover, the abutment member  123  can be eliminated such that the overhanging member  133  is directly coupled to the neck  121  or the shaft  112 .  
      With reference to  FIGS. 9-13 , a device for removing modular forms in accordance with a third embodiment of the present invention is indicated generally by the reference number  210 . Like elements with the device shown in  FIGS. 1-3  are indicated by like reference numbers preceded by “2”. The device  210  is generally the same as the device  10  except for the pulling head. Accordingly, the device  210  and its operation will be described in detail only with respect to the structure that is different from that of the device  10 .  
      A pulling head  220  is fixedly coupled to a shaft  212  at the forward end  214 . The pulling head  220  includes a neck  221 , an abutment member  223  and a projection  225 . The neck  221  defines a threaded bore  227  for being threadably received on the shaft  212  at a forward end  214  thereof. A first side  229  of the abutment member  223  is coupled to the neck  221 , and a second side  231  of the abutment member, generally facing a direction opposite to that of the first side, is for abutting against a face of a form to be removed. An overhanging member  233  extends outwardly from an upper end  235  of the abutment member  223  in a direction generally away from the second side  231  thereof. As shown in  FIGS. 9 and 11 , the overhanging member  233  extends downwardly at an angle of approximately 30 degrees relative to a plane defined by the upper end  235  of the abutment member  223 , but can lie in the same plane as the upper end or extend outwardly therefrom at other various angles without departing from the scope of the present invention. The projection  225  includes a generally round or cylindrical pin  237 , preferably a ⅝ hardened steel pin, mounted to and extending outwardly from the overhanging member  233  in a direction generally transverse to a plane defined by the overhanging member.  
      The pulling head  220  of the device  210  is designed for removing DURAND aluminum forms or other compatible forms that define generally round holes along an upper surface thereof. The pin  237  is inserted into a hole in the aluminum frame of a form along an upper surface thereof. The angle of the overhanging member  233  relative to a central axis of the neck  221  and the shaft  212  permits the pin  237  to be easily inserted in a hole at an upper end of a form that is above the operator&#39;s head, and permits the shaft to extend downwardly at an angle relative to the horizontal from the forward end  214  of the shaft toward the handle end of the shaft in order to permit the operator to move the slide hammer  218  at a comfortable and accessible level.  
      In operation, to remove the first form on a wall, the pin  237  is inserted in a center hole of the aluminum frame of the form at an upper end thereof. The slide hammer  218  is then moved along the shaft  212  until the slide hammer impacts against the stop member  252 . When the slide hammer  218  impacts the stop member  252  adjacent to the handle end of the device  210 , the impact creates a shock that will help “pop” the form free from the wall. Several such “pops” may be needed to completely remove the form from the wall. Once the first form is removed, the pin  237  is then inserted into the left or right hand hole in the top of the form that is to be removed next. If an operator is stripping forms in a direction to the left, the pin  237  is inserted in the hole furthest to the left. If the operator is stripping forms in a direction to the right, the pin  237  is inserted in the hole furthest to the right. Either way, the device  210  will be located to the side of the form that is in the direction that the operator is stripping the wall.  
      In order to remove inside corners, the pin  237  of the device  210  is inserted onto the top of the corner or into a hole on the side of the corner—preferably the highest or lowest hole. The form ties need to be broken off or bent back away from the corner form in order for the device to be able to completely remove the form from the wall.  
      Although the pulling head  220  of the device  210  is shown and described in an exemplary embodiment by way of example, it should be understood that the pulling head can take other various forms without departing from the scope of the present invention. For example, the neck  221  can be eliminated such that the pulling head  220  is directly or otherwise permanently coupled to the shaft. Moreover, the abutment member  223  can be eliminated such that the overhanging member  233  is directly coupled to the neck  221  or the shaft  212 .  
      With reference to  FIGS. 14 and 15 , a pulling head for removing modular forms in accordance with a fourth embodiment of the present invention is indicated generally by the reference number  320 . The pulling head  320  is for attaching to a shaft including a slide hammer assembly as previously described and shown in  FIGS. 1, 4  and  9 .  
      A device including the pulling head  320  is preferably used for removing plywood style forms that range in thickness up to 1⅛″. There are several form manufacturers that produce forms on which the pulling head  320  can be effectively used. Some of the manufacturers are, for example, Gates, Advance, Simplex, Symons, Rapid-Form, Dura-Form and Four Seasons.  
      The pulling head  320  includes a neck  321 , an extension member  323  and an engagement member  325  defining a channel  327 . The neck  321  defines a threaded bore  324  for being threadably received on a shaft as shown in  FIGS. 1, 4  and  9  at a forward end thereof. A first portion  329  of the extension member  323  is coupled to the neck  321 , and a second portion  331  of the extension member supports the engagement member  325 . As shown in  FIG. 14 , the first portion  329  of the extension member  323  extends downwardly at an angle of approximately 30 degrees relative to a plane defined by an upper surface of the first portion  329  of the extension member, but can lie in the same plane as an upper surface of the second portion  331  or extend outwardly therefrom at other various angles without departing from the scope of the present invention.  
      When in an operative position, the engagement member  325  depends generally downwardly from the second portion  331  of the extension member  323  and defines a downwardly facing open-ended channel  327  for being received over an upper end of a form to be removed from a wall. More specifically, the engagement member  325  includes an upper wall  335 , and first and second side walls  337 ,  339  cooperating with one another to define the channel  327 . As shown in  FIG. 14 , the side walls  337 ,  339  are spaced from one another in generally parallel relation, and each perpendicularly extend from the upper wall  335 . The angle of the first portion  329  relative to the second portion  331  of the extension member  323  permits the engagement member  325  to be easily received over an upper end of a form that is above the operator&#39;s head, and permits the shaft to extend downwardly at an angle relative to the horizontal from the upper end of the shaft toward the handle end of the shaft in order to permit the operator to move the slide hammer at a comfortable and accessible level.  
      In operation, the channel  327  defined by the engagement member  325  is received over an upper end of the modular form to be removed. Once in place, the operator quickly pulls the slide hammer along the shaft until it makes contact with the stop member on the handle end of the device. The shock created by the slide hammer hitting the stop pops the form free from the wall—typically within a few pulls. The same procedure is used until all of the forms have been removed from the wall.  
      Although the pulling head  320  is shown and described in an exemplary embodiment by way of example, it should be understood that the pulling head can take other various forms without departing from the scope of the present invention. For example, the neck  321  can be eliminated such that the pulling head  320  is directly or otherwise permanently coupled to the shaft. Moreover, the extension member  323  can be eliminated such that the engagement member  325  is directly coupled to the neck  321  or the shaft.  
      With reference to  FIGS. 16 and 17 , a pulling head for removing modular forms in accordance with a fifth embodiment of the present invention is indicated generally by the reference number  420 . The pulling head  420  is for attaching to a shaft including a slide hammer assembly as previously described and shown in  FIGS. 1, 4  and  9 .  
      A device including the pulling head  420  is preferably used for removing plywood style forms that range in thickness up to 1⅛″. There are several form manufacturers that produce forms on which the pulling head  420  can be effectively used. Some of the manufacturers are, for example, Gates, Advance, Simplex, Symons, Rapid-Form, Dura-Form and Four Seasons.  
      The pulling head  420  includes a neck  421 , an extension member  423  and an engagement member  425  defining a channel  427 . The neck  421  defines a threaded bore  424  for being threadably received on a shaft as shown in  FIGS. 1, 4  and  9  at a forward end thereof. The extension member  423  has a first longitudinal end  429  coupled to the neck  421 , and a second longitudinal end  431  supporting the engagement member  425 . As shown in  FIG. 16 , an upper portion of the extension member  423  is generally disposed in a plane that is parallel to a central axis of the bore  424  defined by the neck  421 .  
      When in an operative position, the engagement member  425  depends generally downwardly from the extension member  423  and defines a downwardly facing open-ended channel  427  for being received over an upper end of a form to be removed from a wall. More specifically, the engagement member  425  includes an upper wall  435 , and first and second side walls  437 , 439  cooperating with one another to define the channel  427 . As shown in  FIG. 16 , the side walls  437 ,  439  are spaced from one another in generally parallel relation, and each perpendicularly extend from the upper wall  435 . Because the upper wall  435  of the extension member  423  lies in a plane that is parallel to a central axis of the bore  424  defined by the neck  421 , a shaft when attached to the neck extends horizontally outwardly from the pulling head  420 , as opposed to extending downwardly from the pulling head  320  shown in  FIGS. 14 and 15 . The horizontal orientation of a shaft attached to the pulling head  420  permits an operator to remove forms having an upper end elevated as high as six feet relative to the operator while standing on a concrete footing, or elevated forms that will be removed while the operator is standing on planking mounted off of the back side of the forms.  
      In operation, the channel  427  defined by the engagement member  425  is received over an upper end of the modular form to be removed. Once in place, the operator quickly pulls the slide hammer along the shaft until it makes contact with the stop member on the handle end of the device. The shock created by the slide hammer hitting the stop pops the form free from the wall—typically within a few pulls. The same procedure is used until all of the forms have been removed from the wall.  
      Although the pulling head  420  is shown and described in an exemplary embodiment by way of example, it should be understood that the pulling head can take other various forms without departing from the scope of the present invention. For example, the neck  421  can be eliminated such that the pulling head  420  is directly or otherwise permanently coupled to the shaft. Moreover, the extension member  423  can be eliminated such that the engagement member  425  is directly coupled to the neck  421  or the shaft.  
      As will be recognized by those of ordinary skill in the pertinent art, numerous modifications and substitutions may be made to the above-described embodiment of the present invention without departing from the scope of the invention. Accordingly, the preceding portion of this specification is to be taken in an illustrative, as opposed to a limiting sense.