Automatic Operator for Groove-Grinding Machines

V. A. Beinarovich, A. I. Zaitsev, M. P. Tabinsky,
G. P. Znamensky

(Presented by the scientific seminar of the Electromechanical Faculty)

The successful fulfillment of the program for building a communist society in our country is inconceivable without a significant improvement in the utilization of the internal reserves of socialist production. The most important factor accelerating the development of socialist industry is the intensification of production at existing enterprises. Intensification of production through the use of a high degree of mechanization and automation makes it possible, in the shortest possible time, to solve the problem of rapidly increasing the output of products.

An important reserve for reducing production costs and increasing output is the modernization of equipment. An especially important factor is the modernization of nonautomatic equipment with the aim of converting it to an automatic operating cycle. Conversion to automatic control makes it possible to include such machines in automatic lines, thereby making it possible to solve problems of comprehensive automation of production. In modern machine building, grinding processes occupy a significant share. In the bearing industry, grinding is the principal type of machining of products. Auxiliary operations on most grinding machines are performed by service personnel, and only the machining process itself is automated. At the Department of EPP an automatic operator has been developed for groove-grinding machines of the Leningrad plant. On these machines all auxiliary operations were performed by workers. The worker moved away the measuring head, unclamped the diaphragm chuck, removed the ground ring, inserted a new blank, brought up the measuring head, pressed the “Start” button, and only then did the automatic process of grinding the ring groove begin. With the creation of the automatic operator, all these operations are automated. The automatic operator makes it possible to automate completely the process of grinding the grooves of bearing rings. With automation of the transport means, a real possibility is created for establishing an automatic flow line.

The proposed automatic operator consists of the following units.

1. A mechanism for feeding the ring from the magazine into the chuck.
2. A mechanism for inserting and withdrawing the measuring head.
3. A mechanism for unclamping the diaphragm chuck.

1. Mechanism of the ejector for ground rings.
   Figure 1 shows the kinematic diagram of an automatic operator for groove-grinding machines of the Leningrad plant.

Let us consider the principle of operation of the automatic operator using the LZ-5M machine as an example.

Kinematic diagram

The automatic operator works by means of the main working motions of the machine and with the aid of a specially modified electrical circuit.

1. Release of the chuck is effected by rotation of the oscillating table of the workhead.

2. Automatic feeding of rings from the storage magazine into the chuck is effected by oscillation of the workhead table and by longitudinal movement of the grinding headstock.

3. Entry and withdrawal of the measuring head into and from the grinding zone takes place by longitudinal movement of the grinding headstock.

4. Ejection of the ground ring is carried out by a spring ejector when the diaphragm chuck is released.

Below we shall consider the operation of the units of the automatic operator shown in Fig. 1.

When the required size of the groove being ground in the ring is reached, the measuring head gives a command to stop the oscillations of the workhead table in the middle position and to retract the grinding headstock to the idle position. At this time the grinding headstock, through block 1, tensions cable 2, which in turn moves lever 3. By means of this lever, the tip of the measuring head is lowered, the position lock of the head is raised as far as stop 4, after which measuring head 24 is withdrawn from the grinding zone.

When the grinding headstock moves back to the extreme idle position, an electric limit switch is actuated and a command is given to switch on the oscillation motor of the workhead table. By means of the special electrical circuit, one complete oscillation of the table takes place. When the table turns to position A, the chuck is released, the ground ring is ejected from the chuck, the unmachined ring is withdrawn from the magazine and positioned opposite the chuck.

This occurs as follows. Roller 5 tensions cable 6, one end of which is fastened to eccentric 7 and the other end to the grinding headstock. The cable turns the eccentric to the chuck-release position, and spring ejector 14 ejects the ground ring from the chuck. Further rotation of the eccentric causes the pawl of feeder 9 to be released by means of stop 8. After this, by means of spring 10, feeder 11 is pushed out of magazine 12 together with the unmachined ring, the latter being held on the feeder by means of mandrel 13.

As a result of further rotation of the workhead table to position B, rocker 15, resting on roller 16, moves away from the workhead and, by means of spring rod 17, moves the feeder in the direction of arrow D. At the same time the mandrel of the feeder with the unmachined ring enters chuck 18.

As rocker 15 moves still farther away from the workhead, the eccentric is turned by flexible rod 19 to the “chuck clamped” position. The ring is firmly secured in the chuck. During the return of the workhead table to the middle position, feeder 11, moving in the direction of arrow C, withdraws mandrel 13 from the chuck and stops.

Fig. 1.

View along M–M

In this position, by means of the electrical circuit, a command is given to bring the grinding wheelhead up to the chuck for the beginning of the next grinding work cycle. At this time guide 20, rigidly fastened to the grinding wheelhead, moves in the direction of arrow $H$. Roller 21, rolling along the contour of the guide, moves into position $E$. By means of flexible link 22, feeder 11 is turned and the mandrel of feeder 13 is set opposite magazine 12.

After the feeder has been withdrawn toward the magazine, measuring head 24 is introduced into the chuck by spring 23. The grinding wheelhead is introduced into the working zone, and grinding begins. During the oscillation of the table, by means of rocker 15 and spring rod 17, the feeder enters the magazine, picks up the next unmachined ring, and is held in this position by latch 9 until the beginning of the next cycle.

Conclusions

1. The design of the automatic operator is simple to manufacture, set up, and operate, and inexpensive to produce.

2. Owing to the simplicity of the automatic-operator design, a highly skilled setup man is not required.

3. Thanks to the “travel” electromechanical circuit, the automatic operator works in a strictly defined sequence under any operating modes of the machine.

4. The automatic-operator design is fast-acting, since its entire operating cycle takes 2.5 seconds.

5. The automatic-operator design may be adopted as a standard one for groove-grinding machines of models LZ-5, LZ-8, and LZ-29.