Gun for applying mastic material

Abstract

 A gun for applying mastic material especially butyl mastic sealant comprises a barrel (1) for receiving mastic material (M), e.g. in a cartridge (2), the barrel (1) having electric heater means (10) about it for heat softening the mastic material (M) so that on application of pressure to the softened mastic material (M) it is ejected from the nozzle (7) in suitable form for application. As shown pressure is applied to the mastic material (M) by air under pressure admitted to the rear of the barrel (1) through a trigger operated valve (31), the air acting on an internal rear closure (22) of the cartridge container (20). The nozzle (7) is detachable for front end loading of a cartridge (2) in the barrel (1), a rear part (77) of the nozzle (7) piercing the forward end of the cartridge container (20) when the nozzle (7) is remounted on the barrel (1). An outer casing (11) is heat insulated from the heating means (10) by an air space (A).

Description

[0001] This invention refers to guns for dispensing mastic material, e.g. in the application of such material as a sealant to double glazing window units or for other purposes.

[0002] The invention relates more particularly to such guns in which the gun barrel receives a cartridge of mastic material for ejection of the material from a nozzle of the gun on application of pressure to the mastic material within the barrel.

[0003] The object of the invention is to provide an improved gun which can be conveniently operated in ejecting mastic material especially butyl mastic sealant in a required condition for application. Practical advantages of the invention in this respect will be apparent from the following disclosure.

[0004] According to the invention a gun for applying mastic material comprises a barrel for receiving mastic material, e.g. in a a cartridge; nozzle provided at the forward end of the barrel; heating means such as one or more electric heaters provided about the barrel for heating the latter and mastic material received therein; a body secured to the rear end of the barrel; a handle carried by said body and operable means carried by said body for applying pressure to mastic material received in the barrel whereby the mastic material softened by the heating means can be ejected from the nozzle of the barrel.

[0005] In a practical example of the gun the construction and arrangement is as follows, reference being had to the accompanying drawings in which:-

[0006] The barrel 1 of the gun which receives a cartridge 2 consisting of a cylindrical container 20 containing butyl mastic material M is housed in an outer casing 11 and fitted about the barrel 1 is electric heating means 10 of coil or band type. In the example shown two heating units 10 of semi-cylindrical form are secured about the barrel 1 and are bolted together by their flanges 110. However a heating coil wound about the barrel 1 may be employed, i.e. fitted as a sheath. The outer casing 11 is of heat insulating material such as nylon or nylon based material and an annular insulating air space A is provided between the heaters 10 and casing 11 and through which cooling air flow can take place to maintain the casing 11 at a temperature at which it can be held during continuous use of the gun.

[0007] The casing 11 is shown mounted from the barrel 1 by front and rear end plates 9. As will be seen in FIGURE 2 the plates are of square form in the cylindrical casing 11 so as to leave gaps 119 for cooling air flow in the space A.

[0008] The barrel 1 is secured at its rear end to a body 33 of suitable plastic heat insulating material carrying a pistol grip handle 3 provided with a trigger 30 controlling an air inlet valve 31 from a compressed air supply, a connecting pipe for which is shown at 34. When the valve 31 is trigger operated air under pressure is able to pass along a passage 330 in the body 33 to act on an internal closure 22 of the cartridge 2 in order to push the closure along the interior of the container 20, i.e. when the mastic material M has been softened from its cold quite hard condition by heat from the heaters 10. The closure 22 thus acts as a plunger or piston in the container 20 on the mastic material M.

[0009] In use the heaters 10 are connected to a source of current supply by a flexible cable 5 andtheir operation is controlled by a temperature controller or thermostat 6 in heating the mastic material M and maintaining it at a required temperature whereby it is in a suitable fluid or plastic condition. The operating temperature of the heaters 10 may be of the order of 180°C.

[0010] When the mastic material M is at the required temperature, trigger operation of the valve 31 enables air under pressure to be applied to the closure 22 and causes it and the softened mastic material M to be advanced forwardly along the interior of the container 20 for expulsion of the mastic material through a nozzle 7 at the forward end of the barrel 1. Ejection of the softened mastic material by compressed air avoids the need for mechanical operation of the gun in this respect and thus minimises operator fatigue when continuously using the gun.

[0011] Both the barrel 1 and nozzle 7 and mounting of the latter are of suitable heat conductive material or metal in order to ensure that the mastic material M is maintained at the required softening temperature during ejection from the nozzle 7 and application to work receiving the material. The nozzle 7 is detachably mounted on or in relation to the barrel 1 for front end loading of the latter with a cartridge 2 and in the example shown the nozzle 7 is carried by a cap 72 which screws onto a threaded ring 71 fitted about the forward end of the barrel 1. The cap 72 is provided with a radial handle 70 for readily enabling it to be firmly screwed onto the barrel ring 71 or unscrewed therefrom.

[0012] A co-axial tubular member 73 of the cap 72 receives a holder 74 for the nozzle 7 and a rearwardly extending tube 77 of the latter. The tubular member 73 accommodates a reduced end part or neck 23 of the cartridge container 20, the end of the neck 23 being initially closed but which is pierced by the pointed rear end 770 of the tube 77 as the cap 72 is screwed home on the barrel 1. Thus passage of softened mastic material M along the tube 77 and through the nozzle 7 can take place.

[0013] Other suitable detachable mounting of the nozzle ? on the barrel 1 can be employed such as bayonet or like connection for access to the forward open end of the barrel in order to load it with a cartridge 2 or remove a spent cartridge. For firm location of the cartridge 2 in the barrel after screwing on the nozzle cap 72, the rear end of the container 20 seats against a heat resistant seal 32 carried by the body 33.

[0014] mastic As will be appreciated, the gun enables the softened material to be conveniently applied in a continuous or uninterrupted manner as required, i.e. until the cartridge is exhausted. Effective operation in this way has been borne out by practical tests.

Claims

1. A gun for applying mastic material comprises a barrel (1) for receiving mastic material (M), e.g. in a cartridge (2); a nozzle (7) provided at the forward end of the barrel (1); heating means (10) such as one or more electric heaters provided about the barrel (1) for heating the latter and mastic material (M) received therein; a body (33) secured to the rear end of the barrel (1); a handle (3) carried by said body (33), and operable means (30,31) carried by said body (33) for applying pressure to mastic material (M) received in the barrel (1) whereby the mastic material (M) softened by the heating means (10) can be ejected from the nozzle (7) of the barrel (1).

2. A gun for applying mastic material according to claim 1 wherein the means (30,31) for applying pressure to mastic material (M) received in the barrel (1) consists of an operable valve (30,31) carried by said body (33) for admitting fluid under pressure such as compressed air into the rear end of the barrel (1) for the application of pressure to mastic material (M) received in the barrel (1).

3. A gun for applying mastic material according to claim 2 wherein the barrel (1) is adapted to receive a cartridge (2) containing mastic material (M) in which the cartridge container 20 is provided with an internal closure (22) at its rear end, fluid under pressure such as compressed air admitted by the valve (30,31) into the rear end of the barrel (1) acting on said closure (22) in order to advance the latter and heat softened mastic material (M) along the barrel (1) for ejection of the softened mastic material (M) from the nozzle (7) of the barrel (1).

4. A gun for applying mastic material according to any of claims 1 to 3 wherein the nozzle (7) is detachably mounted on the forward end of the barrel (1) for front end loading of the barrel (1) with mastic material (M), e.g. in a cartridge (2).

5: A gun for applying mastic material according to claim 4 wherein a rearwardly extending part (77) of the nozzle (7) is adapted to pierce the container (20) of a cartridge (2) of mastic material (M) inserted in the barrel (1) on the nozzle (7) being remounted on the forward end of the barrel (1).

6. A gun for applying mastic material according to any of the preceding claims wherein the rear end of the barrel (1) contains sealing means (32) against which the rear end of a container (20) of a cartridge (2) of mastic material (M) seats when fully inserted in the barrel (1).

7. A gun for applying mastic material according to any of the preceding claims wherein a heat insulating outer casing (11) is provided about the heating means (10) and barrel (1).

8. A gun for applying mastic material according to claim 7 wherein an air space (A) is provided between the outer casing (11) and the heating means (10), said space (A) having openings (119) for cooling air flow into it in order to provide heat insulation between the heating means (10) and the outer casing (11).

Drawing