SU435918A1 - MACHINE FOR CUTTING THREAD - Google Patents

Description

one

The invention relates to the field of mechanical engineering and can be used during machining.

Known machines for threading a tap, made in the form of a bed-tank filled with liquid, in which a float carrying a spindle block is placed. The tap cuts when manually feeding, then cutting is self-engaging.

Known machines have the following disadvantages.

Manual feed does not provide sufficient equal speed of feed and screwing, which often leads to breakage of the turns of the intake part of the tap when entering the hole or to deformation of the first turn of the thread when the tap goes out of the hole.

There is no even increase in the axial force from zero to the maximum at the insertion area of the intake part of the tap.

In the self-rolling process, all the axial cutting force closes on the gage coils, which leads to deformation of the thread coils, especially in bags with plastic materials.

In order to improve threading accuracy by adjusting the axial force in the proposed machine, the hollow float is made communicating through the pipeline with the spool, the inlet and outlet of which are installed

2

adjustable throttles, and an adjustable throttle and a valve are installed on the discharge branch of the pipeline in front of the spool, which additionally releases pressure from the cavity

float, with the valve and valve connected

and triggered by path switches

during the forward movement of the spindle

block.

In addition, in the proposed machine cavity

the float communicates through the bottom part with liquid in the reservoir, for example, through an opening.

FIG. 1 shows the kinematic scheme of the proposed cutting machine.

taps; in fig. Figure 2 shows the change in axial force on the tap during threading.

The machine has a tank 1 with liquid and a column 2. A float 3 is placed in the tank.

The design of a hollow float can be of three types: rigid, with a cavity connected to the liquid of the reservoir through the bottom part, then a medium is fed into the cavity that is lighter than the liquid in the reservoir;

rigid, with a cavity associated with the atmosphere, then the cavity is filled with a medium heavier than the liquid in the reservoir;

soft, airtight, then the cavity is filled with medium;

lighter than liquid in tank

By changing one of the methods of lifting force of the float, getting it positive or negative, achieve a certain axial force on the tap during the cutting process. Thus, in the designs of the first, third type, the axial insertion is created by the weight of the moving parts of the spindle unit, in the design of the second type by the weight of the heavy medium.

Rack 4 connects the float with the spindle 5. On the bracket 6 there are path switches 7 and 8 of the extreme positions associated with an electropneumatics 9, having a tube 10. At the input of the spool there is an adjustable throttle I, a gear 12 and a crane 13, and an adjustable throttle 14. The switches 7 and 8 are triggered by the cam 15. On the bracket 16 a weight 17 and a drive 18 are mounted.

Column 2 is equipped with a second bracket 19 - with a lead 20, which can be freely turned upwards and bounded below. A pressure switch 21 is mounted on the bracket 16, controlling the valve 22, which is mounted on the tube 23 with an adjustable choke 24.

Before starting, the machine is set up.

By changing the weight 17, the weight of the moving parts is set equal to the maximum axial force for a given tap. The weight is measured with a dynamometer and the left position of the spool rod when the cavity of the float is connected to the atmosphere and its lifting force is zero.

The choke 14 regulates the feed rate of the spindle assembly (spindle 5, bracket 16), which should be equal to or slightly higher than the screwing speed when the tap enters the hole. Similarly, the throttle 11 adjusts the lifting speed, which must be equal to or slightly higher than the unscrewing speed. To determine the speed, an electrical seconds measure is used, connected in parallel with switches 7 and 8.

With the valve 22 open and etching through the choke 14, the resistance of the throttles 24 is set so that during the insertion of the intake part of the tap into the hole, the pressure in the float cavity is equalized to atmospheric, and the weight of the moving parts of the spindle assembly is equivalent to the axial force required for the tap.

When the switch 7 is turned on (Fig. 1), the actuator 18 begins to rotate, at the same time the electropneumatic 9 is triggered to the left extreme position, the air from the cavity of the float 3 through the tube 10 and the throttle 14 rushes into the atmosphere and the bracket 16

spindle 5 begins to move downward at a speed equal to the screwing speed, which prevents the first edge of the tap from being hit.

At the moment of cutting the tap, the driver 20 turns on an additional push switch 21, which remains on until the intake part of the tap is fully inserted. During this time, working from him to; la

pan 22 releases all pressure from the cavity of the float, while the weight of the moving parts provides an increase in axial force to the calculated value. The tool is supplied at POC 0 (zone I is not shown);

zone II is the moment of increasing axial force to a design value that remains constant; zone 1P - the main thread length; Zone IV is the moment of reversal and change of axial force.

After actuation of the switch 8, the actuator 18 is reversed, and the electropneumatic 9 is turned to the right, and the air through the valve 13, the gearbox 12, the throttle 11 and the tube 10 rushes into the cavity

the float 3, its lift force increases, compensates for the weight of moving parts, removes the axial force on the tap, and with a slight excess, creates a negative axial force needed to save the last thread from rolling.

As the switch 21 is passed upwards, the leader 20 leans freely, without pressing the switch. Further, when the switch 7 is turned on, the process is repeated again.

With automation, the zone turns the part to a new position (not shown in the diagram).

Pd. 8 dme T Invention

Claims (2)

1. A tapping machine made in the form of a tank bed filled with liquid in which a float carrying a spindle unit is placed, characterized in that, in order to increase the thread cutting accuracy by adjusting the axial force, the hollow float communicates through the pipeline with spool, inlet and outlet mounted adjustable throttles, and an adjustable throttle and a valve are installed on the discharge branch of the pipeline in front of the spool, additionally relieving pressure from the float cavity, the spool and valve being connected and triggered by the travel switches during the forward movement of the spindle unit. 2. The machine according to claim 1, characterized in that the float cavity is made communicating through the bottom portion with the liquid in the reservoir, for example, through an opening. RP O-R, with OS  And / L - y1 / .. f  f ,,, / J