Pipe Cutting Machine With Spark Actuated Feed Control

Abstract

Pipe cutting machine comprising a grinding wheel for cutting a pipe, means for detecting sparks from the grinding wheel or the pipe in cutting operation, and means for reducing the feeding speed of the grinding wheel, when said means is operated by sparks.

Description

The present invention relates to a pipe cutting machine provided with a control means for feeding speed of the grinding wheel.

In conventional pipe cutting machine, feeding speed is not varied in idling and also cutting stroke.

An object of the present invention is to provide a pipe cutting machine of which grinding wheel may be rapidly fed in idling stroke for increase the working efficiency.

To this end, according to the present invention, the pipe cutting machine comprises a swing arm provided with a grinding wheel for cutting a pipe, a hydraulic cylinder to rotate said swing arm, valve means for reducing the rotating speed of said swing arm, a photo electric means for detecting sparks from the pipe or the grinding wheel in cutting operation, and means for operating said valve means to reduce the speed of the swing arm to a cutting speed when said photo electric means being actuated by sparks.

In the drawings;

FIG. 1 is a side view of a pipe cutting machine in accordance with the present invention; and

FIG. 2 is a diagrammatical view showing operation thereof.

Referring to the drawings, in FIG. 1 a pipe 1 to be cut is supported by a plurality of rollers 3 provided on a bed 2 and arranged along the pipe and is held by pressure rollers 3a. A grind wheel arm 4 is pivotally provided on the bracket 5 by the pin 6. A grinding wheel 8 is rotatably provided on the end of the arm 4 by a shaft 7 and adapted to be rotated by a belt 12 engaged with a pulley 9 on the shaft 7 and a pulley 11 on the shaft of the motor 10. An air cylinder 13 is connected on the bed 2 by a pin 14 and the piston rod 15 is connected to the end of the arm 4 by a pin 16. A braking oil hydraulic cylinder 17 is secured to the air cylinder 13 and the piston rod 18 is connected to the piston rod 15 of the air cylinder by a member 18 thereby both piston rods can be simultaneously moved. Opposite chambers of the braking cylinder 17 are connected each other through flow metering valves 20 and 21 and a solenoid controlled valve 22. A photo transistor 23 is provided on the bracket 5 to be directed to the pipe 1.

FIG. 2 shows the idling stroke, more particularly, chambers of the braking cylinder 17 are communicated through lower resistance valve 20. Therefore, the arm 4 is quickly rotated in the counter-clockwise direction by operation of the air cylinder 13. When the grinding wheel 8 contacts with the pipe 1, the sparks actuates the photo transistor 23 to emanate an electrical signal, the electrical signal is transmitted to the solenoid controlled valve 22 through an amplifier 24, thereby the solenoid controlled valve is operated to change the passages to connect the higher resistance valve 21 to the chambers of the braking cylinder 17. Thus, the rotating speed of the arm 4 is reduced to a cutting speed. In the return stroke, the solenoid controlled valve 22 is operated by not shown switch, so that the lower resistance valve 20 is connected to the braking cylinder, thus the arm 4 is quickly returned. It will be noted that the means may be arranged to be operated without the braking cylinder 17 by providing a flow control means for the air cylinder 13.

Claims

What is claimed is:

1. A pipe cutting machine comprising a swing arm provided with a grinding wheel for cutting a pipe, a hydraulic cylinder to rotate said swing arm, valve means for reducing the rotating speed of said swing arm, a photo electric means for detecting sparks from the pipe or the grinding wheel in cutting operation, and means for operating said valve means to reduce the speed of the swing arm to a cutting speed when said photo electric means is being actuated by sparks.