Hot air gun

• US 4,629,864 A
• Filed: 03/08/1984
• Issued: 12/16/1986
• Est. Priority Date: 12/23/1983
• Status: Expired due to Fees

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Wilson, Peter H.
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): Lateef, M. M.
• Application Number:
  US06/587,704
• Time in Patent Office: 1,013 Days
• Field of Search: 219/368, 219/369, 219/370, 219/371, 219/373, 219/374, 219/222, 34/99
• US Class Current: 392/385
• CPC Class Codes: B44D 3/168 by electrically heating air heaters using electric energy supply, the air being in direct contact with the heating medium, F24H3/0405
• CPC Class Codes: F24H 3/0423 hand-held air guns

Abstract

A Hot Air Gun capable of stripping paint comprising a casing made of a pair of clam-shell members, an electric motor, a fan drivingly connected to the electric motor, heating means comprising a former and a helical heating element projecting outside the casing and defining an air outlet at its ends, and an outer tubular member surrounding the projecting part of the inner tubular member. The inner and outer tubular members are clamped in position by the securing together of the pair of clam-shell members of the casing. Baffle means are provided at the upstream end of the helical heating element for blocking an air flow path inside the element. The exposed surface of the outer tubular member is covered with a plurality of circumferential ribs.

Claims

1. A hot air gun capable of stripping paint and comprising:

a clam-shell housing defining a cavity,

an electric motor disposed in said cavity,

a fan in said cavity drivingly connected to the electric motor,

heating means comprising a former and a helical heating element mounted on the former, said heating element projecting from said housing downstream of the fan,

an inner tubular member generally coaxially surrounding the helical heating element and having opposed first and second ends, said second end being securely clamped within said clam-shell housing, and the first end projecting from the housing and defining an air outlet, and

an outer tubular member having opposed first and second ends, said second and being separately clamped by said clam-shell housing, and the first end projecting from the casing in coaxial relation to the inner tubular member,

wherein the inner and outer clamped tubular members are circumferentially spaced thereby defining an annular air flow path therebetween.

2. A hot air gun according to claim 1 in which the electric motor, the fan and the heating means together define a sub-assembly which is fixed in said cavity solely by the opposed halves of the clam shell housing.

3. A hot air gun according to claim 2 in which the sub-assembly includes a tubular housing in which the motor is disposed, the motor being spaced from the tubular wall of the housing and the fan being arranged to create an air flow through the tubular housing for cooling the motor.

4. A hot air gun according to claim 1 in which the helical heating element tapers towards its downstream end and the inner tubular member also tapers towards its downstream end.

5. A hot air gun according to claim 1 in which the exposed surface of the outer tubular member is covered with a plurality of ribs.

6. A hot air gun according to claim 5 in which the ribs extend circumferentially around the outer tubular member.

7. A hot air gun according to claim 1 further including baffle means at the upstream end of the helical heating element for generally precluding air flow inside the element and for diverting air flow through an annular space between said heating element and said inner tubular member.

8. A hot air gun according to claim 7 in which the baffle means comprises a pair of half-moon baffle elements together defining a circular baffle coaxial with the helical heating element.

9. A hot air gun according to claim 1 further including a hanger pivotally mounted on the housing for movement between a retracted position in which the hanger is located in a recess in the housing and an operative position in which the hanger projects from the housing.

10. A hot air gun according to claim 1 wherein the housing defines an upper barrel portion and a lower hand grip portion, a rear end wall is provided in the barrel portion defining that part of the barrel furthest from the air outlet and an air inlet is provided in the casing in a rear portion of the barrel forward of the rear end wall.

11. A hot air gun comprising:

a housing,

an electric motor disposed in said housing,

a fan in said housing drivingly connected to the electric motor,

heating means comprising a former and a helical heating element mounted on the former, said heating element projecting from said housing downstream of the fan,

an inner tubular member generally coaxially surrounding the helical heating element and having opposed first and second ends, said second being secured within said housing and the first end projecting from the housing and defining an air outlet at its end, and

an outer tubular member having opposed first and second ands, said second end being separately affixed to the housing, and the first end projecting from the housing in coaxial relation to the inner tubular member,

wherein the inner and outer tubular members are circumferentially spaced thereby defining an annular air flow path therebetween, the exposed surface of the outer tubular member being covered with a plurality of circumferential ribs.

12. A hot air gun capable of stripping paint and comprising:

a housing,

an electric motor disposed in said housing,

a fan in said housing drivingly connected to the electric motor,

heating means comprising a former and a helical heating element mounted on the former, said heating element projecting from said housing downstream of the fan,

an inner tubular member generally coaxially surrounding the helical heating element, having opposed first and second ends, said second end being affixed to the housing, and the first end projecting from the housing and defining an air outlet at its end, and

an outer tubular member having opposed first and second ends, said second end being affixed to the housing, and the first end projecting from the housing in coaxial relation to the inner tubular member, wherein the inner and outer tubular members are circumferentially spaced thereby defining an annular airflow path therebetween, and

baffle means inside the inner tubular member at the upstream end of the helical heating element for diverting air flow through an annular space between the outside of the heating element and the inner tubular member.

13. A hot air gun capable of stripping paint comprising:

a clam-shell housing defining a cavity;

an integral sub-assembly including an electric motor, a fan drivingly connected to said motor, and a helical heating element mounted on a former downstream of said fan, the motor and fan of said sub-assembly being disposed in said cavity with said heating element projecting therefrom, and said sub-assembly being secured in position solely through engagement by cooperating components of the opposed halves of said clam-shell housing;

an inner tubular member coaxially disposed around said heating element and having a first end securely clamped between cooperating components of the opposed halves of said clam-shell housing and a second end defining an air outlet; and

an outer tubular member coaxially disposed around said inner tubular member and having a first end securely clamped between cooperating components of the opposed halves of said clam-shell housing;

said inner and outer tubular members defining an annular air flow passage.

14. A hot air gun capable of stripping paint comprising:

a housing defining a cavity having an open end;

electrical means in said cavity for generating air flow between inlet ports in said housing and said open end;

a helical heating element projecting from said open end in the path of said air flow;

an inner tubular member coaxially surrounding said heating element and defining a first annular passage around said heating element, said inner tubular member having a first end fixed proximate the periphery of the opening in said housing and a second end defining an air outlet;

baffle means upstream of said heating element for diverting said air flow into said first annular passage;

an outer tubular member coaxially surrounding said inner tubular member and defining a second annular passage, said outer tubular member having a first end fixed proximate the periphery of the opening in said housing and a second end defining an outlet for said second annular passage; and

means at the opening in said housing for conducting a portion of said air flow into said second annular passage.