6 610 159

6,610,159 Title:

Obstruction avoidance continuous seam welding system

An apparatus for seaming roofing membranes to one another, wherein one of the membranes is secured to an underlying support structure by at least one protruding fastener, the apparatus including a wheeled carriage having an upwardly extending push/pull bar, a power supply carried by the carriage, the power supply driving the wheeled carriage, a heating assembly carried by the carriage and powered by the power supply, the heating assembly including a fan and a heating element, wherein the fan blows ambient air over the heating element and generate a heated airflow sufficient to fuse the roofing membranes to one another, a nozzle coupled to the heating assembly for directing the heated airflow between the two membranes, the nozzle having a pair of outer channels and an elevated center channel disposed between the pair of outer channels, the elevated channel passing over the at least one protruding fastener, and a variable pressure roller assembly coupled to the carriage, the roller assembly having a pair of outer rollers and a spring-biased center roller disposed between the pair of outer rollers, the spring-biased roller aligned with the elevated channel and passing over the at least one protruding fastener so as to form a substantially continuous width seam except where interrupted by the protruding fastener.

What is claimed is:

1. An apparatus for seaming roofing membranes, wherein one of the membranes is secured to an underlying support structure by at least one protruding fastener, the apparatuscomprising: a carriage; a heating assembly carried by said carriage, said heating assembly generating heat capable of bonding the membranes to one another; and a seaming assembly carried by said carriage, said seaming assembly directing the generatedheat to the membranes while also applying pressure to the membranes so as to form a substantially continuous width seam except where interrupted by the protruding fastener, wherein said seaming assembly comprises a variable pressure assembly for applyingpressure to the heated membranes, said variable pressure assembly having at least one constant pressure source and at least one variable pressure source, said variable pressure source positioned to pass over the at least one protruding fastener.

2. The apparatus according to claim 1, wherein said seaming assembly comprises: a nozzle for directing heated air between the membranes, said nozzle having at least two channels, wherein one of said channels is slightly elevated so as to form agap sized to pass over the at least one protruding fastener.

3. The apparatus according to claim 2, wherein said heating assembly further comprises: a duct for directing the heated air from said heating assembly; an elbow for transferring the heated air from said duct to said nozzle; and each saidchannel having a top plate opposed by a bottom plate connected to one another by side walls, one of said bottom plates being slightly elevated with respect to the other bottom plate.

4. The apparatus according to claim 2, wherein said nozzle has three channels, comprising: two outer channels each having a bottom plate and a tapered top plate connected to each other by at least one side wall; and a center channel disposedbetween said two outer channels, said center channel having a center top plate connected to said tapered top plates and center bottom plate connected to said outer channel bottom plates, said center bottom plate forming a clearance gap that passes overany protruding fastener.

5. The apparatus according to claim 4, wherein said bottom plates have slots and said top plates have vent holes therethrough.

6. The apparatus according to claim 1, wherein said variable pressure assembly further comprises: a frame coupled to said carriage; at least one constant pressure roller carried by said frame; and at least one spring-biased pressure rollercarried by said frame, wherein said spring-biased pressure roller accommodates any protruding fasteners when encountered, but otherwise applies a substantially equivalent amount of pressure as said at least one constant pressure roller.

7. The apparatus according to claim 6, wherein said at least one spring-biased pressure roller is disposed between two constant pressure rollers.

8. The apparatus according to claim 1, wherein said seaming assembly comprises: a nozzle for directing heated air between the membranes, said nozzle having at least two channels, wherein one of said channels is slightly elevated so as to form agap sized to pass over the at least one protruding fastener.

9. The apparatus according to claim 8, further comprises: a plurality of wheels journaled to said carriage; and a motor carried by said carriage, said motors rotating at least some of said wheels.

10. An apparatus for seaming roofing membranes to one another, wherein one of the membranes is secured to an underlying support structure by at least one protruding fastener, the apparatus comprising: a wheeled carriage having an upwardlyextending push/pull bar; a power supply carried by said carriage, said power supply driving said wheeled carriage; a heating assembly carried by said carriage and powered by said power supply, said heating assembly including a fan and a heatingelement, wherein said fan blows ambient air over said heating element and generate a heated airflow sufficient to fuse the roofing membranes to one another; a nozzle coupled to said heating assembly for directing the heated airflow between the twomembranes, said nozzle having a pair of outer channels and an elevated center channel disposed between said pair of outer channels, said elevated channel passing over the at least one protruding fastener; and a variable pressure roller assembly coupledto said carriage, said roller assembly having a pair of outer rollers and a spring-biased center roller disposed between said pair of outer rollers, said spring-biased roller aligned with said elevated channel and passing over the at least one protrudingfastener so as to form a substantially continuous width seam except where interrupted by the protruding fastener.

11. The apparatus according to claim 10, wherein spring-biased roller is offset from said pair of outer rollers, such that the width of said spring-biased roller overlaps at least a portion of the width of each said outer roller.

12. A nozzle for use with an apparatus that seams two membranes to one another, the apparatus carrying a heating assembly that generates forced heated air, the nozzle comprising: a duct having one end coupled to the heating assembly; and aplurality of channels connected to an opposite end of said duct, said plurality of channels including a pair of outer channels with an elevated channel therebetween, said elevated channel sized to pass over fastening devices that secure one of themembranes.

13. A variable pressure roller assembly for use with an apparatus that seams two membranes to one another, the apparatus carrying a heating assembly that generates forced heated air, between the membranes, the assembly comprising: a framecoupled to the apparatus; at least one constant pressure roller carried by said frame; and at least one spring-biased pressure roller carried by said frame, wherein said spring-biased pressure roller accommodates any protruding fasteners whenencountered, but otherwise applies a substantially equivalent amount of pressure as said at least one constant pressure roller, said rollers applying pressure to the membranes to create a bond therebetween.

14. A method for full-width seaming roofing membranes to one another comprising: placing a first roofing membrane having a lateral edge on a roof structure; securing said lateral edge to said roof structure with at least one protruding fastenerthat extends above said lateral edge; placing a second roofing membrane on the roof structure and on at least said lateral edge to cover said at least one protruding fastener; positioning an apparatus proximally said lateral edge, said apparatus havinga heating assembly and a seaming assembly; heating said first and second roofing membranes to a predetermined temperature with said heating assembly; moving said seaming assembly to apply pressure to said first and second membranes to form asubstantially continuous width seam between said first and second roofing membranes except where interrupted by the protruding fastener; providing said seaming assembly with a plurality of rollers: and biasing one of said plurality of rollers, saidbiased roller passing over said protruding fastener during said moving step.

15. The method according to claim 14, further comprising: providing said heating assembly with a nozzle; inserting said nozzle between said lateral edge and said second roofing membrane, said nozzle having a gap sized to pass over saidprotruding fastener during said moving step.

16. The method according to claim 14, wherein said moving step comprises: applying a uniform pressure to said membranes with all of said plurality of rollers.