Heat nozzle for welding floor seams

A portable, handheld seam welding gun for filling in seams between sheets of linoleum flooring is provided with a unique heat nozzle. The heat nozzle of the invention couples the heating barrel of a conventional floor seam welding gun to a conventional hollow welding tip by receiving the heating air inlet tube of the tip within the confines of a downstream socket formed in the body of the heat nozzle. A larger, upstream socket formed in the body of the heat nozzle fits onto the heating barrel of the handheld, portable welding gun. A plurality of preheating jets are formed on the underside of the body of the heat nozzle to preheat the region of the channel immediately to the rear of the welding tip just before molten sealant flows into that portion of the channel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is a heat nozzle designed for use with a portable, handheld seam sealing welding gun for dispensing a molten sealant to join adjacent sheets of flooring.

2. Description of the Prior Art

In laying flooring that is sold commercially in sheets, such as linoleum flooring, adjacent sheets of flooring are positioned side by side and cut to the desired shape. In the past the flooring sheets have been secured to the floor by adhesive compound. To secure the flooring sheets to the floor, the compound is applied to the floor and the cut sheets of flooring are laid in position, one by one. Once each sheet of flooring is laid, the next adjacent flooring sheet is brought into position and pressed against the floor with the linear edges of adjacent flooring sheets residing in mutual abutment.

One major problem with laying sheets of flooring in this manner is that the adhesive bond between the underside of the flooring sheets and the subfloor therebeneath is sometimes inadequate. Quite often areas of the sheets of the linoleum flooring will tend to separate from the subfloor when the adhesive bond between the subfloor and the flooring sheets deteriorates due to age, movement of the subfloor, or improper installation.

The separation of areas of flooring sheets from the subfloor is particularly pronounced at the interfaces between adjacent sheets of flooring. The edges of adjacent flooring sheets which are supposed to reside in firm, mutual abutment, will sometimes tend to rise slightly from the subfloor. This presents both an unsightly appearance and also leads to a significant deterioration of the floor because of the separation that occurs when the edges of adjacent sheets of flooring rise. When separation between adjacent sheets of flooring occurs in this way, moisture, dirt and debris often find their way into the crack that forms between the flooring sheets, thus leading to further deterioration of the floor.

In the floor installation trade the use of fusible plastics to form a seal between the abutting edges of adjacent sheets of flooring has gained increased popular acceptance. According to this technique the edges of sheets of flooring are not cut perpendicular to the plane of the expanse of the flooring as has historically been the practice. Rather, the edges of the flooring are cut so that adjacent sheets of flooring, when moved into abutting relationship, define an upwardly facing, elongated groove where they meet. That is, the sheets of flooring are cut so that the exposed upper surface covers a slightly smaller area than the concealed undersurface, thus providing adjacent surfaces forming a groove or channel between adjoining sheets of flooring. These adjacent surfaces can be bonded together using a fusible thermoplastic applied from above. The color of the thermoplastic is chosen to match the color of the flooring so as to render the demarcation between adjacent sheets of flooring largely undetectable.

Automated machines have been developed for applying a fusible plastic sealant to seams between adjacent sheets of flooring. Such automated machines roll upon the floor and apply a bead of molten thermoplastic along the seam between adjacent sheets of flooring. The heat required is provided by electrical resistance heating. The molten thermoplastic quickly cools and bonds to the adjoining edges of adjacent sheets of flooring. Once the adjoining edges of sheets of flooring have been sealed in this manner, they will not separate from each other, even in the event that the bond between the undersides of the sheets of flooring and the subfloor deteriorates with time. This prevents a noticeable gap from forming between adjacent sheets of flooring.

While automated seam sealing machines of the type described do create firm, durable sealed seams between adjacent sections of sheet flooring, they are quite large, bulky, heavy, and complicated to operate. Furthermore, they are quite expensive so that their cost is well beyond the resources of the average sheet flooring installer.

Therefore, a much more economical type of machine for creating a seam of fused thermoplastic between adjacent sheets of flooring was developed. Specifically, portable, handheld seam welding guns have been available commercially for quite some time. Such handheld guns are sold at only a fraction of the cost of automated seam welding machines. These are also typically electrically powered and melt a thermoplastic bead by means of resistance heating.

Handheld seam welding guns of this type are typically configured with a generally cylindrical body forming the rear portion of the gun and a heat conducting member projecting forwardly from the body along a longitudinal axis. An adapter having a heat concentration nose, typically formed of a highly conductive metal, such as copper or a copper alloy, is mounted on the heat conducting member and includes a heating tip mounting tube. The heating tip mounting tube projects forwardly along the longitudinal axis of the body and has of a narrow, tubular configuration. This type of adapter is often referred to in the trade as a “pencil tip” adapter. The heating tip mounting tube fits into a hollow heating tip.

A conventional, portable, handheld seam welding gun heating tip includes a hollow cylindrical sleeve that fits onto the heating tip mounting tube and another tubular structure that accommodates an elongated length or stick of thermoplastic that is fed into the interior of the heating tip and melted therein. Conventional, portable handheld seam welding guns of this type are manufactured in Europe by Leister Process Technologies, CH-6060 Sarnen, Switzerland. Other, comparable commercial seam welding guns are also available, such as the Zinser K-5 handheld welder that is available from Zinser Schweisstechnik GmbH, Stuttgarter Strasse 145, 73061 Ebersback/Fils, Stuttgart, Germany.

While conventional, handheld, portable seam welding guns of the type described can produce high-quality seams, the rate at which the seam can be filled with sealant utilizing a portable, handheld welding gun is rather limited. Specifically, using a portable, handheld seam welding gun an experienced flooring installer can fill seams between abutting sheets of linoleum flooring with sealant at the rate of about four feet a minute. In contrast, the expensive, automated seam sealing machines of the type described can be operated to fill seams at the rate of about sixteen feet per minute.

SUMMARY OF THE INVENTION

Conventional, handheld, floor seam welding guns employ an electrical heating element and blower mounted in a casing that forces heated air through a narrow air duct in a heating tip mounting tube, oriented at an angle relative to a heat conducting metal nose cap. A hollow welding tip is mounted externally on the narrow mounting tube that projects from the nose cap of the welding gun.

In a conventional device such as this the volume of hot air that may be forced into the hollow heating tip is rather limited. Consequently, the rate at which the sticks or rods of plastic sealant can be melted and the floor seam heated beneath the melting chamber in the welding tip is limited. However, the present invention overcomes this basic limitation in portable, handheld seam welding guns that has existed for so long.

In one broad aspect the present invention may be considered to be a heat nozzle for a handheld flooring seam sealing device. The heat nozzle of the invention is comprised of an enclosing body having a top side and underside, and defining therewithin an upstream socket and a downstream socket. The upstream socket receives therewithin a heat-conducting barrel of a handheld floor seam welding gun. The downstream socket receives therewithin a heat welding tip. The downstream socket is oriented at an acute angle of between about ten degrees and about thirty degrees from coaxial alignment with the upstream socket. Consequently, the sockets form an obtuse angle in the heat nozzle body. In addition, at least one preheating jet is formed in the body. The preheating jet, or preferably a plurality of preheating jets, lead from the upstream socket to the underside of the body of the heat nozzle.

By providing a downstream socket into which the hot air inlet tube of the welding tip can be inserted, the volume of hot air flow from an otherwise conventional, handheld floor seam welding gun is markedly increased. This is possible since the entire area of the inlet duct defined within the hot air inlet tube of the welding tip can conduct hot air. In contrast, in a conventional welding tip mounting structure which is the narrow“pencil tip” tube projecting from the heat concentration nose occupies a considerable portion of the cross-sectional area of the hot air inlet of heat welding tips that are commercially available. Consequently, there is a constriction in air flow into the hollow welding tip, which limits the rate at which the sealant can be melted and dispensed in molten form to fill a seam between adjacent flooring sheets.

A further feature of the heat nozzle of the invention is the provision of one or more preheating jets in the heat nozzle. Some heat welding tips currently on the market are equipped with a separate duct in communication with the melting chamber within the tip. This duct terminates in an orifice located behind the rear extremity of the dispensing mouth of the tip. As the welding gun is pulled toward the installer, along the seam to be filled, the preheating duct in the welding tip raises the temperature of the flooring at the seam to enhance adhesion of the sealant thereto when the molten sealant is dispensed through the mouth of the welding tip. Such a heat welding tip is described in prior U.S. Pat. No. 5,656,126 and is available as the Turbo welding tip from Martinez Enterprises, located at 6381 Western Avenue, Buena Park, Calif. 90621. However, in conventional practice all preheating in handheld, manually operated tools has been performed through a duct within the heating tip itself.

However, according to the present invention, at least one, and preferably as many as three separate preheating jets are formed in the body of the heat nozzle of the invention. The first of these jets is located beneath and parallel to the downstream socket that receives the hot air conducting tube of the heat welding tip. Since it is positioned in this manner, the first preheating jet directs a stream of hot air into the seam immediately to the rear of the heat welding tip. This advance preheating raises the temperature of the flooring at the seam, thereby reducing the time it takes to melt the sealant and fill the seam.

Even more rapid preheating is achieved by providing second and third heating jets in the heat nozzle of the invention. These second and third heating jets are preferably oriented at an angle of between forty and sixty-six degrees relative to the first heating jet so that they emit jets of hot air that heat the material of the flooring at the seam even in advance of the first preheating jet which directs hot air at the seam just behind the welding tip. As a consequence, the speed at which a flooring seam can be filled with sealant material is greatly increased relative to the speed with which this task can be performed utilizing conventional handheld seam welding guns equipped with “pencil tip” adapters.

As previously indicated, an experienced flooring installer can operate a conventional, handheld flooring seam welding gun to perform a professional seam sealing job at the rate of about four feet per second. However, utilizing the same welding gun and essentially the same welding tip, but employing a heat nozzle according to the invention in place of a “pencil tip” adapter, the rate of seam sealing can be approximately tripled. That is, utilizing the same heat welding gun and welding nozzle, but with the adapter of the invention, an installer can fill seams at the rate of about twelve feet per minute.

In another broad aspect the invention may be considered to be a device for sealing seams between abutting sheets of flooring. The device of the invention is comprised of a portable, handheld, seam-sealing welding gun, a heat nozzle according to the invention, and a hollow heat welding tip. The heat welding gun has a casing with a longitudinal axis and an elongated, heat-conducting element projecting from the casing along the longitudinal axis. The heat nozzle has a body with an underside and opposing upstream and downstream ends. The terms “upstream” and “downstream”, as employed herein, refer to the direction of hot air flow from the rear of the handheld seam welding gun toward the welding tip. An upstream socket is defined within the upstream end of the heat nozzle of the invention. The upstream socket receives the heat-conducting element of the handheld, seam-sealing welding gun therewithin. A downstream socket is defined within the downstream end of the heat nozzle. The upstream and downstream ends of the heat nozzle form an enclosed obtuse angle therebetween at the underside of the body.

At least one preheating jet is formed in the underside of the body. The preheating jet or jets are in communication with the upstream socket and emanate from the underside of the body, between the upstream and downstream ends, within the enclosed obtuse angle defined therebetween. The hollow, heat welding tip has a heating inlet tube that is inserted into the downstream socket of the heat nozzle body. The heat welding tip also has a welding stick receiving tube which terminates in a melting chamber. The welding tip also has an elongated, open mouth with forward and rearward extremities into which and out of which molten sealant from the melting chamber flows.

In still another aspect the invention may be considered to be an improvement in a portable, handheld seam-sealing welding gun for dispensing molten sealant to seal seams between adjacent sheets of flooring. Such a welding gun includes a casing that houses an electrical power source and an air blower. The welding gun also has a heating barrel. A welding tip with a hot air inlet tube is also employed.

The improvement of the invention is comprised of a heat nozzle formed with a body that has an upstream socket that fits over the heating barrel to receive heated air therefrom, and a downstream socket, smaller than the upstream socket and inclined downwardly therefrom to form an obtuse angle relative thereto. At least one preheating jet is formed in the body and is in communication with the upstream socket. The preheating jet or plurality of jets are oriented to direct heated air toward a flooring seam in advance of the welding tip.

The invention may be described with greater clarity and particularity with reference to the accompanying drawings.

DESCRIPTION OF THE EMBODIMENT

FIG. 1depicts a device, indicated generally at10, for sealing seams between adjoining, abutting sheets of flooring52and54on a flat floor surface51. The seamsealing device10is comprised of a portable, handheld, seam-sealing welding gun11equipped with a heat nozzle14constructed according to the invention, and also a hollow heat welding tip16. The heat welding gun11is a conventional, Leister Triac model portable, handheld floor seam welding gun. The generally cylindrical casing24of the seam welding gun11defines a longitudinal axis indicated at30. The welding gun11is powered by commercially available, alternating current through a power supply cord28. Near its front end the outer casing24of the heat welding gun11defines a pair of diametrically opposed, radially outwardly projecting lugs32having a rectangular configuration, as illustrated.

Heat is produced within the casing24by an electrical resistance heating element. A blower within the casing24draws air in through the vent openings of a grill located in the circular rear end33of the casing24. The heated air is forced longitudinally, generally along the alignment of the longitudinal axis30of the seam welding gun11and into a narrower, cylindrical, heat-conducting barrel34that projects from the casing24along the longitudinal axis30.

The seam welding gun11is supported from beneath by a mobile, stabilizing guide36of the type depicted and described in prior U.S. Pat. No. 5,656,126, which is hereby incorporated by reference in its entirety. The stabilizing carriage36has a forward end38and a rearward end40. The intermediate portion of the carriage36forms a fork that diverges from the forward end38to the rearward end40, as illustrated in FIG.2. The rearward end40of the carriage36has two pairs of laterally separated brackets41,43at its outboard extremities that accommodate an axle shaft that extends across the entire width of the rearward end40. Each of the pairs of laterally separated brackets accommodates a roller42mounted for rotation about the axle between brackets41,43in each pair. Between the bracket pairs there is a cylindrical drum44mounted upon the axle. A generally disc-shaped track follower46is located at the center of the rear end40of the carriage36between a pair of spacer drums44. The track follower46has a relatively sharp peripheral edge that follows a linear seam50defined between two, abutting, adjacent sheets of flooring52and54.

The width of the peripheral edge of the track follower46is such that it fits into the channel50defined between the abutting edges of the linoleum flooring sheets52and54. The track follower46is held laterally centered between the pairs of brackets41,43at the rearward end40of the carriage36by the spacer drums44.

The forward end38of the carriage36is formed as a linear stem or tongue having a transverse aperture therethrough to receive a bolt56and an internally tapped bore normal to the plane of the carriage36to receive an elevation adjusting set screw58. The seam-sealing device10is further provided with a longitudinally split, cylindrical, annular collar60, notched out to receive the lugs32of the casing24. At its underside the collar60has a pair of radially projecting mounting ears62that extend downwardly from the cylindrical portion of the collar60. The mounting ears62are secured to the forward end38of the carriage36by means of the bolt56. The collar60also includes a downwardly projecting elevation-adjusting flange64that is radially aligned with the elevation-adjusting set screw58. The casing24of the welding gun11is captured within the collar60and held tightly in coaxial alignment therewith by means of the bolt56which squeezes the mounting ears62toward each other and clamps them against the forward end38of the carriage36.

The welding gun11is held at an incline relative to the floor51with the longitudinal axis30of the welding gun11residing at an angle of typically between about five degrees and thirty degrees relative to the horizontal surface of the floor51. A gross adjustment of the angle of inclination is controlled by loosening the bolt56slightly and orienting the angulation of the carriage36relative to the casing24to approximately the desired angle. The bolt56is then tightened. Fine adjustment may be performed by rotating the elevation adjusting set screw58. The set screw58may be advanced toward the adjustment flange64, thereby increasing the angle of the welding gun11relative to the floor51. Alternatively, counter rotation of the adjustment screw58reduces that angle. The tip of the adjustment set screw58bears against the underside of the flange64to hold the welding gun11at a selected angle of inclination relative to the floor51.

The heat welding tip16may be selected from among any number of commercially available heat welding tips for handheld seam welding guns. Preferably, the heat welding tip16is either a Turbo round tip 5 mm or a Turbo triangular tip 5.7 mm seam welding tip, depending upon the size and cross-sectional configuration of the sticks70of sealant used. These welding tips are sold by Leo Martinez Enterprises and described in considerable detail in U.S. Pat. No. 5,656,126.

The heat welding tip16has a longitudinally split, cylindrical, annular air inlet tube66and a welding rod receiving tube68for receiving a 3, 4, or 5 mm welding stick70, typically formed of vinyl plastic. The air inlet tube66and the welding rod receiving tube68converge downwardly as illustrated inFIGS. 1 and 3and intersect at a melting chamber72located directly above an elongated, open mouth74that has a forward extremity76and a rearward extremity78. The welding tip16further defines within its structure a preheating orifice79and a separate preheating duct80terminating in the orifice79that is located behind the rear extremity78of the mouth74. The welding tip16also has an upturn toe81in front of the forward extremity76of the mouth74.

The novel feature of the invention resides in the construction of the heat nozzle12. The heat nozzle12is molded as a unitary, hollow, cast metal body82, preferably fabricated of brass, copper, or aluminum. The metal body82has a top83and an underside85and is formed with a cylindrical, annular shaped upstream end84that defines a cylindrical socket86therewithin. The interior diameter of the socket86is selected as appropriate for the particular model of welding gun11employed. When utilized with a Leister welding gun, as illustrated in the drawings, the interior diameter of the open end of the socket86is preferably about three cm, although the diameter can be varied slightly by compression or expansion of the radially projecting fastening lugs88and90. The fastening lug90is internally threaded to receive the threaded end of a clamping screw92. The fastening lugs88and90reside on either side of a sheet longitudinally split at the upstream end of the upstream socket86, and may be moved slightly due to the presence of an arcuate expansion slot91in the structure of the body82, which is visible in FIG.2. The interior diameter of the socket86is just large enough to receive the cylindrical, heat-conducting barrel34of the heat welding gun11. The wall thickness of the socket86is preferably about 0.3175 cm.

The opposite, downstream end94of the heat nozzle body82has a generally rectangular outer cross-sectional configuration, as illustrated inFIG. 5, preferably about 1.65 cm in height and about 1.33 cm in width. A cylindrical, downstream socket96is defined within the downstream end94of the body82and is preferably about 1 cm in diameter. This is a suitable size to receive within its radial confines the end of the heating air inlet tube66of the preferred embodiment of the heat welding tip16. The heating air inlet tube66is inserted into the mouth of the socket96and is preferably, permanently secured to the downstream end94of the body82by welding so that the heat welding tip16is always in the proper orientation relative to the heat nozzle12.

A very important feature of the invention is that there is no obstruction to the cylindrical channel defined in the heating air inlet tube66of the welding tip16. That is, the socket96radially surrounds the exterior of the heating air inlet tube66. In a conventional pencil tip adapter system, a narrow, cylindrical annular mounting and air supply tube of the pencil tip adapter is inserted into the cylindrical opening of the air inlet tube66. Thus, the portion of the opening of the air inlet tube66occupied by the structure of the pencil tip mounting tube is blocked, thus restricting the flow of all the air into the welding tip16to the narrow passageway defined within the pencil tip mounting tube. In the present invention the heat welding tip16is attached to the welding gun11by insertion of the inlet tube66into the downstream socket96, not by insertion of a mounting and air conducting tube into the opening defined within the structure of the air inlet tube66.

The downstream socket96is oriented at an acute angle of between about ten degrees and about thirty degrees from coaxial alignment with the upstream socket86. Preferably, the sockets86and96are offset from coaxial alignment by an angle of about twenty degrees relative to each other. The sockets86and96thereby form an obtuse angle relative to each other of about one hundred sixty degrees.

At least one, and preferably three, preheating jets are formed at the underside85of the heat nozzle body82. These preheating jets lead from the upstream socket86to the underside85of the body82.

In the preferred embodiment of the heat nozzle12illustrated, a first preheating jet98is formed which is oriented parallel to the downstream socket96. The first preheating jet98is preferably spaced about 1.9 cm from the downstream socket96. The preheating jet98is formed as a cylindrical, annular duct or passageway through the structure of the downstream end94of the body82and is preferably about 2.54 cm in length from its intersection with the upstream socket86to its terminus at its outlet port100. The opening of the first preheating jet98is preferably between about 0.45 and about 0.50 cm in diameter.

A second, cylindrical preheating jet102is also formed in the underside85of the nozzle body82upstream from the first preheating jet98. The second preheating jet102is oriented at an acute angle of between about forty and about sixty-six degrees relative to the first preheating jet98. The second preheating jet102is preferably oriented at an angle of about fifty-three degrees relative to the first preheating jet98. The second preheating jet102is also a cylindrical duct or passageway and is about 0.55 cm in length from its intersection with the upstream socket86to its outlet port104. The diameter of the second preheating jet98is also between about 0.45 and about 0.50 cm.

A third preheating jet106is also formed in the underside85of the heat nozzle body82and is closely spaced upstream from and parallel to the second preheating jet102. The third preheating jet106is between about 0.9 and about 1 cm in length from its intersection with the upstream socket86to its outlet port108, and is likewise between about 0.45 and about 0.50 cm in diameter. As illustrated, the third preheating jet106has a length greater than the length of the second preheating jet102. The second and shortest preheating jet102is located a distance of about 0.635 cm from the third preheating jet106and right in front of it. The second preheating jet102is located between the first preheating jet98and the third preheating jet106. The three preheating jets98,102, and106are all in mutual, coplanar alignment with each other, as well as with the centers of both the upstream socket86and the downstream socket96.

To utilize the floor seam sealing device10the heat nozzle12with the welding tip16permanently attached thereto is fastened onto the barrel34of the heat welding gun11. The heat conducting barrel34is inserted into the upstream socket86with the clamping screw92in a slightly loosened condition. The angular orientation of the heat nozzle12is adjusted so that the preheating jets98,102, and106all reside in coplanar relationship with the center of the underside85of the casing24. That is, the body82of the heat nozzle12is rotationally adjusted on the heat gun barrel34until the preheating jets98,102, and106of the heat nozzle12all reside in coplanar relationship with the flange64. This ensures that the preheating jets98,102, and106will all be directed straight into the channel50defined between the mutually abutting flooring sheets52and54. Once the heat nozzle12is in proper angular adjustment relative to the welding gun11, the clamping screw92is tightened.

The flooring installer then determines the proper angle at which the axis30of the welding gun casing24should reside relative to the floor51. This angle will typically be between about ten and thirty degrees. The most appropriate angle will be determined in part by the line of sight of the installer over the top of the heat welding gun11, but another very important -factor is the degree of softness or hardness of the welding stick70, as different plastics utilized as seam welding sticks70have somewhat different melting temperatures. If the welding stick70is relatively soft, the angle between the axis30of the welding gun casing24and the floor51will be relatively greater, as illustrated inFIG. 1, than if the plastic forming the welding sticks70is harder.FIG. 1illustrates the angle at which the heat welding gun11will normally be elevated relative to the floor51for a relatively soft plastic sealant stick70using the clamping bolt56and the height adjusting set screw58.

A greater amount of heat should be supplied when using a relatively high melting temperature welding stick70. This is necessary to adequately raise the temperature at the portion of the channel50just to the rear of the welding tip16. Therefore, the angle of orientation of the alignment of the welding gun casing24, and therefore the heat nozzle12as well, will be reduced, as illustrated in FIG.3. The ports100,104, and108of the preheating jets98,102, and106, respectively, should be just far enough above the channel50so that the molten material from the seam welding sticks70flows smoothly into the channel50as it is melted in the melting chamber72. Care should be exercised so that the temperature in the channel50is not so great as to lower the viscosity of the molten sealant so much that it flows onto the surfaces of the linoleum sheets52and54on either side of the channel50.

With the angulation of the entire device10adjusted relative to the floor51by means of the bolt56and height adjusting set screw58, the heat welding gun11is turned on and the welding stick70is inserted into the welding rod receiving tube68. The upturned toe81of the welding tip16is positioned at the start or forward end of the channel50. The track follower46is positioned in the channel50with the rollers42in contact with the sheets of flooring52and54. The flooring installer then pulls the heat welding device10rearwardly, to the left as viewed inFIGS. 1 and 2, pulling the track follower46along the channel50. The heat welding gun11draws ambient air in through the grill at the rear end33of the casing24. The air is heated within the casing24, and forced by an internal blower through the heating barrel34into the heat nozzle12.

The main portion of the heated air flows from the upstream socket86into the downstream socket96and into the cylindrical opening of the air inlet tube66of the heating tip16. The seam sealant stick70is then melted in the melting chamber72with a certain amount of preheating provided by the preheating duct80within the heating tip16, as described in U.S. Pat. No. 5,656,126. In addition, the portion of the channel50immediately behind the mouth74of the heating tip16is preheated by a portion of the air from the upstream socket86that flows into the preheating jets98,102, and106and out of the ports100,104, and108, respectively. Air is ejected from the downstream socket96and from the preheating jets98,102, and106at a temperature of about three hundred fifteen degrees Centigrade.

Due to the preheating effect provided by the preheating jets98,102, and106of the heat nozzle12, and due to the increased volume of heated air that is provided to the heating tip16through the heating air intake tube66, as contrasted with a conventional pencil tip adapter, the channel50can be filled with molten sealant, indicated at70′ inFIG. 4, much more rapidly than has heretofore been possible with handheld seam sealant welding guns. Utilizing the seam sealing device10illustrated inFIGS. 1 and 2, the channel50can be filled at a rate of twelve feet per minute, as contrasted to the much slower rate of about four feet per minute typical of conventional portable, handheld seam sealing gun systems. Quality workmanship in sealing seams between sheets of flooring at the speed achieved using the present invention has not previously been obtainable using portable, manual seam welding guns.

Undoubtedly, numerous variations and modifications of the invention will become readily apparent to those familiar with floor covering seam sealing systems. For example, while the welding gun11illustrated in the drawings is a Leister Triac is welding gun, any other commercially available welding gun, including all other Leister models and all Zinser models, may be utilized in accordance with the present invention. Also, although the preferred welding tip16employed is a Turbo triangular or round tip, any other commercially available welding tip having a heating air inlet tube may be utilized to advantage with the heat nozzle of the invention. Accordingly, the scope of the invention should not be construed as limited to the specific embodiment depicted and described, but rather is defined in the claims appended hereto.