Method and apparatus for welding a roofing membrane

Abstract

A machine for welding an overlapped region of two adjacent strips of material and a method of using the same. The machine includes a housing with front and rear ends, a wheel train engaged with the housing for moving the housing across the material; a nozzle on the housing having a welding head at a free end; the nozzle being positionable at least partially beneath the housing's bottom wall for welding the overlapped region; front and rear pressure rollers engaged with the housing, where the front roller is positioned forwardly of the welding head and the rear roller is positioned rearwardly of the welding head; wherein the rear pressure roller applies pressure to the overlapped region when the wheel train moves the housing in a forward direction; and the front pressure roller applies pressure to the overlapped region when the wheel train moves the housing in a reverse direction.

1 . A machine for welding an overlapped region of two adjacent strips of a material, said welding machine comprising:
 a housing having a front end and a rear end, and having a longitudinal axis extending between the front and rear ends;   a wheel train engaged with the housing and adapted to move the housing across the material to be welded;   a nozzle engaged with the housing and having a welding head at a free end thereof;   a front pressure roller engaged with the housing and positioned forwardly of the welding head; and   a rear pressure roller engaged with the housing and positioned rearwardly of the welding head; wherein the rear pressure roller is adapted to apply pressure to the overlapped region when the wheel train moves the housing in a forward direction parallel to the longitudinal axis; and the front pressure roller is adapted to apply pressure to the overlapped region when the wheel train moves the housing in a reverse direction parallel to the longitudinal axis.   
     
     
         2 . The welding machine as defined in  claim 1 , further comprising a motor provided on the housing, said motor being operatively engaged with the wheel train and being configured to selectively drive the wheel train in the forward direction or in the reverse direction. 
     
     
         3 . The welding machine as defined in  claim 2 , further comprising a blower motor assembly that is operatively engaged with the nozzle and the welding head, said blower motor assembly being operable to heat the welding head to a temperature sufficient to weld the overlapped region together. 
     
     
         4 . The welding machine as defined in  claim 1 , wherein the nozzle is pivotably engaged with the housing; and wherein the nozzle is pivoted about an axis that is oriented generally parallel to the longitudinal axis of the housing. 
     
     
         5 . The welding machine as defined in  claim 1 , wherein said nozzle is pivotable relative to the housing in a first direction to move the welding head at least partially under a bottom wall of the housing; and wherein the nozzle is pivoted relative to the housing in a second direction to move the welding head outwardly from under the bottom wall of the housing. 
     
     
         6 . The welding machine as defined in  claim 1 , further comprising a handle engaged with the housing, wherein the handle is movable between a first position where at least a portion of the handle extends beyond the front end of the housing and a second position where the at least the portion of the handle extends beyond the rear end of the housing. 
     
     
         7 . The welding machine as defined in  claim 1 , further comprising a handle pivotably engaged with the housing between a first position and a second position; and when the handle is in the first position the handle is adapted to be used by an operator to move the housing in the forward direction; and when the handle in the second position the handle is adapted to be used by the operator to move the housing in the reverse direction. 
     
     
         8 . The welding machine as defined in  claim 3 , further comprising a power source retained within the housing, said power source being operatively engaged with one or both of the motor and the blower motor assembly. 
     
     
         9 . The welding machine as defined in  claim 1 , further comprising a first gripper bar fixedly engaged with the housing. 
     
     
         10 . The welding machine as defined in  claim 1 , wherein the first gripper bar is provided in a first color and a remaining portion of the housing is provided in a second color and the first color differs from the second color; and wherein the first color is indicative of the first gripper bars being sufficiently cool enough to touch when the welding machine is operational. 
     
     
         11 . The welding machine as defined in  claim 10 , wherein the nozzle is provided with a handle; and wherein the nozzle handle is provided in the same first color as the first gripper bar and is indicative of the nozzle handle being sufficiently cool enough to touch when the welding machine is operational. 
     
     
         12 . A method of heat welding a series of overlapped regions of adjacent strips of flexible material that extend from a first end of a structure to a second end of the structure; said method comprising the steps of:
 positioning a welding machine in a first orientation;   moving the welding machine in a first direction;   welding a first overlapped region while moving the welding machine in the first direction;   laterally moving the welding machine to a second overlapped region;   maintaining the welding machine in the first orientation;   moving the welding machine in a second direction, where the second direction is opposite to the first direction; and   welding the second overlapped region while moving the welding machine in the second direction.   
     
     
         13 . The method as defined in  claim 12 , further comprising
 placing a housing of the welding machine in the first orientation relative to the first end and the second ends of the structure;   positioning the welding machine proximate the first end of the structure and adjacent a first end of the first overlapped region;   inserting a welding head on the welding machine between an overlap layer and an underlap layer of the first overlapped region;   heating the welding head;   moving the housing in the first direction along the first overlapped region and toward the second end of the structure;   applying heat from the welding head to the first overlapped region as the housing moves in the first direction; and   applying pressure to the heated first overlapped region as the housing moves in the first direction.   
     
     
         14 . The method as defined in  claim 13 , further comprising:
 welding the first overlapped region until the second end of the structure is reached;   pivoting the welding head into a rest position where the welding head does not extend beneath a bottom wall of the housing;   laterally moving the welding machine to the second overlapped region;   maintaining the first orientation of the housing relative to the first end and the second end of the structure;   pivoting the welding head into a use position and inserting the welding head between an overlap layer and an underlap layer of the second overlapped region;   heating the welding head;   moving the housing in the second direction along the second overlapped region and towards the first end of the structure;   applying heat from the welding head to the second overlapped region as the housing moves in the second direction;   applying pressure to the heated second overlapped region as the housing moves in the second direction; and   welding the second overlapped region.   
     
     
         15 . The method as defined in  claim 13 , further comprising:
 setting a handle on the welding machine into a first position relative to the housing;   engaging the handle; and   moving the welding machine in one of the first direction or the second direction.   
     
     
         16 . The method as defined in  claim 15 , further comprising:
 setting the handle on the welding machine into a second position relative to the housing;   engaging the handle; and   moving the welding machine in one of the first direction or the second direction.   
     
     
         17 . The method as defined in  claim 12 , wherein the step of laterally moving the housing from the first overlapped region to the second overlapped region comprises:
 lifting the welding machine upwardly away from a surface upon which the machine rests using two gripper bars that are provided on a housing of the welding machine.   
     
     
         18 . The method as defined in  claim 14 , wherein pressure is applied to the heated first overlapped region by a first pressure roller provided on the welding machine; and wherein pressure is applied to the heated second overlapped region by a second pressure roller provided on the welding machine. 
     
     
         19 . The method as defined in  claim 12 , wherein the step of moving the welding machine in the first direction is preceded by causing a current to flow in one direction through a motor provided on the welding machine. 
     
     
         20 . The method as defined in  claim 19 , wherein the step of moving the welding machine in the second direction is preceded by causing a current to flow in an opposite direction through the motor. 
     
     
         21 . A nozzle for a welding machine used to heat weld materials together; said nozzle comprising:
 a tubular member having a first end and a second end;   a connector assembly engaged with the first end and being adapted to be engaged with a hose extending outwardly from a housing of the welding machine; and   a welding head provided at the second end of the housing, wherein the welding head is substantially L-shaped when viewed from a first direction and the welding head comprises a first leg that is engaged with the second end of the nozzle and a second leg that extends outwardly from the first leg.   
     
     
         22 . The nozzle as defined in  claim 21 , wherein the welding head is substantially T-shaped when viewed from a second direction that is oriented at 90° to the first direction. 
     
     
         23 . The nozzle as defined in  claim 22 , wherein the second leg comprises a planar member that is oriented generally at right angles to the first leg of the welding head. 
     
     
         24 . The nozzle as defined in  claim 23 , wherein the planar member includes an upper surface and an opposed lower surface; wherein the lower surface is adapted to be oriented generally parallel to a material surface upon which the welding machine is positioned during a welding operation. 
     
     
         25 . The nozzle as defined in  claim 24 , wherein one or both of the upper and lower surfaces of the planar member defines a plurality of apertures therein that are in communication with a bore of the nozzle and are adapted to allow heated air to flow outwardly from the bore of the nozzle and into air surrounding an exterior of the planar member. 
     
     
         26 . The nozzle as defined in  claim 25 , wherein the planar member has a first side edge and a second side edge and an end that extends between the first and second side edges; and wherein one or more of the first and second side edges and the end defines an aperture therein; and wherein the aperture is in communication with a bore of the nozzle and is adapted to allow heated air to flow from the bore and into air surrounding an exterior of the planar member.