# US 5,703,340 A · Method and apparatus for forming a hole for using cooling air in hole forming process

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- Number: US 5,703,340 A
- Document ID: US5703340A
- Status: Granted
- Kind: A
- Application number: 08/504,963
- Filed: 1995-07-20
- Granted: 1997-12-30
- Earliest claimed: 1994-07-21
- Assignees: Fuji Jukogyo Kabushiki Kaisha
- Inventors: Tatsuya Ohta; Masami Moritani
- Web page: https://patentgrep.com/patent/US5703340A

## CPC

- B23K 26/10: using a fixed support {, i.e. involving moving the laser beam}
- B23K 10/00: Welding or cutting by means of a plasma
- B23K 26/348: in combination with arc heating, e.g. tungsten inert gas [TIG], metal inert gas [MIG] or plasma welding
- B23K 26/382: by boring
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

A hole forming apparatus for forming a hole through the side wall of a hollow elongated work without any adhesion of dross generated not only during hole forming operation to the inner wall surface of the work but also without any burning of a rust preventing oil. To cool the working location, cooling air is blown through the opening end of the work so as to generate a stream of cooling air in the interior of the work.

## Claims

### Claim 1

A hole forming apparatus having a plurality of receiving means for receiving a lengthy work mounted on a base frame, a lifter provided between said receiving means and said work for pushing said work to a predetermined position, a plurality of locators for setting said work at said predetermined position, a plasma torch mounted on said base frame for making a hole in said lengthy work, a robot provided at a vicinity of said hole forming apparatus for supporting said plasma torch and for allowing movement to at any direction, and a robot control unit for controlling said robot, comprising:
an air blowing unit with a blowing nozzle mounted on a bracket of said base frame for blowing pressurized air to an open end portion of said work; and
a space member interposed between a cooling head of said bracket and said work for spacing a gap to induce a fresh air into said open end portion and for cooling down said work while forming a hole in said work by said plasma torch so as to avoid rust and dross from adhering near said hole and to obtain a precise diameter of said hole.

### Claim 2 (depends on 1)

The hole forming apparatus as claimed in claim 1, wherein said hole forming tool is a plasma torch.

### Claim 3 (depends on 1)

The hole forming apparatus as claimed in claim 1, wherein said cold air feeding unit consists of a thrust block adapted to be displaced toward the opening end of the work in the forward/rearward direction, a cooling head borne by said thrust block, and a cooling air nozzle held on said cooling head.

### Claim 4 (depends on 1)

The hole forming apparatus as claimed in claim 1, wherein said cooling head is located directly in front of the opening end of the work with a predetermined distance left therebetween so as to allow environmental air to be introduced into the work.

### Claim 5 (depends on 1)

The hole forming apparatus as claimed in claim 1, wherein said predetermined distance is set to be 0.5 to 1.2 times of a diameter of said nozzle.

### Claim 6

A hole forming apparatus comprising:
a plurality of receiving means for receiving a lengthy work mounted on a base frame,
a lifter provided between said receiving means and said work for pushing said work to a predetermined position,
a plurality of locators for setting said work at said predetermined position,
a plasma torch mounted on said base frame for making a hole in said lengthy work,
a robot provided at a vicinity of said hole forming apparatus for supporting said plasma torch and for allowing movement to at any directions,
a robot control unit for controlling said robot,
an air blowing unit with a blowing nozzle mounted on a bracket of said base frame for blowing pressurized air to an open end portion of said work; and
a space member interposed between a cooling head of said bracket and said work for spacing a gap to induce a fresh air into said open end portion and for cooling down said work while forming a hole in said work by said plasma torch so as to avoid rust and dross from adhering near said hole and to obtain a precise diameter of said hole.