Mechanical-hydraulic control device for controlling the locking and unlocking movements of rotary disk in a rotary disc table workpiece processing apparatus

An improved mechanical-hydraulic device for controlling the locking and unlocking movements of a rotary disk—ring gear system comprises a mechanical screw and screw-nut assembly for driving the disk between a locking position, and an unlocking position, and a cooperating hydraulic assembly for controlling the engagement force of the ring gears and accordingly the locking force of the rotary disk to perform high speed and safe locking and unlocking movements of the rotary disk.

BACKGROUND OF THE INVENTION

The present invention relates to an improved device for controlling the locking and unlocking movements of a rotary disk, in a rotary table workpiece processing apparatus.

The invention also relates to an apparatus or machine including such an improved device.

The field of the invention is that of the machines including devices for locking and unlocking a rotary disk such as, for example, the rotary table of a transfer machine, a rotary-table conveyor, a revolver turret and the like in which, after the rotation, the locking of the rotary disk is performed by means of a ring gear coupling (for example of the HIRT type).

Are already known in the prior art machines of the above mentioned type, in which the control of the locking and unlocking movements of the rotary disk is performed by a ball recirculating screw and nut assembly which, on a side, operates on the rotary disk and, on the other side, is rotatively driven by a specifically designed motor-reducing unit.

Thus, as the screw is rotatively operated, the rotary disk is axially driven, with mutual approaching and withdrawing movements between corresponding ring gears, to provide, respectively, the locked and unlocked condition of said rotary disk.

In prior constructions of the above disclosed type, the axial force for mutually engaging the ring gears, correspondingly to the rotary disk locking operation, is fully or substantially fully provided by the ball recirculating screw and nut assembly.

Moreover, as the rotary disk has a vertical axis, to the preceding stresses, the weight of the rotary disk is also added, which, consequently, further stresses the mentioned screw and nut driving assembly.

As a direct consequence of the above disclosed drawbacks, in prior machines of the above mentioned type, the locking and unlocking speed of the rotary disk decreases with an increase of the rotary disk mass itself.

Furthermore, since the engagement force between the ring gears is fixed and determined by the driving assembly operating the screw and screw nut assembly, this effort may be insufficient as the masses to be driven are comparatively large and, anyhow, in machining operations requiring a maximum locking force by the rotary disk.

SUMMARY OF THE INVENTION

Accordingly, the main object of the present invention is to provide an improved mechanical-hydraulic device for locking and unlocking a rotary disk, controlled by a screw-nut screw assembly and a ring gear system, designed for providing high speed and properly controlled locking and unlocking movements of said rotary disk.

Another object of the present invention is to provide a device of the above-mentioned type which is very safe and reliable in operation.

Yet another object of the present invention is to provide such an improved device allowing to properly control and graduate the mutual engagement force of the ring gears, depending on the masses to be driven and the required locking loads.

Yet another object of the present invention is to provide such an improved device which, as the rotary disk has a vertical axis, is adapted to also support the weight of the rotary disk, thereby releasing the screw and screw nut assembly from the force or effort due to the weight of the rotary disk itself.

According to one aspect of the present invention the above mentioned objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a device and apparatus according to the invention.

Further preferred embodiments of the present invention are defined in the dependent claims.

With respect to prior like devices, the inventive device provides the advantage that it allows to drive with a very high speed the rotary disk for performing its locking and unlocking movements, in addition to properly controlling the engagement force of the ring gears, depending on the driven masses and the machining parameters required by the specific machining operation to be carried out.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The inventive device shown inFIG. 1for controlling a rotary disk in a rotary-table workpiece processing apparatus comprises a ball recirculating screw1, one end3of which is coupled to a rotary coupling2, which is in turn driven by a motor4-reducing unit5assembly or geared motor unit.

As shown, the ball recirculating screw1is rotatably engaged inside a fixed screw-nut6, in turn rigid with a driving shaft7.

The driving shaft7is coupled, through a bearing8, to the rotary disk or table10, including a main gear wheel9, driven by a suitably designed motor-reducing assembly.

On the surface11of the disk10facing the machine bed12, is provided a ring gear13(for example of a HIRT type), which can be rotatably driven together with the disk10.

On the surface of the machine bed12facing the disk10, is provided a ring gear14, corresponding to the mentioned ring gear13, and meshing therewith.

Thus, as the screw1is rotatively driven in the screw-nut6, the shaft7will be axially displaced, together with the disk10, between the mutual engagement and disengagement positions of the ring gears13and14, corresponding respectively to the locking and unlocking positions of the rotary disk10.

To the above-mentioned movements of the shaft7and disk10, provided by the disclosed mechanical screw and screw-nut assembly, also contributes the cylinder and piston assembly better shown inFIG. 2and constituting, as it should be apparent to one skilled in the art, a hydraulic assembly constituting an integrated part of the inventive mechanical and hydraulic control device.

More specifically, the cylinder comprises a cylinder chamber15, formed inside the machine bed12.

In said cylinder chamber15is axially slidably received the piston, comprising an enlarged portion16, directly formed on the body of the shaft7.

In a modified embodiment, shown inFIG. 4of the inventive device, the unlocking of the disk10, corresponding to the movement of the shaft7in the direction of the arrow F2is performed by unlocking micro-cylinders19, driven by an unlocking hydraulic circuit20, arranged on the machine bed12.

Said unlocking micro-cylinders19are designed for axially operating against that portion of the cylinder15facing the machine bed12, axially slidably mounted on the piston16, thereby causing the ring gears13and14to be driven away from one another.

In this modified embodiment which specifically relates to the rotary disk unlocking means , the rotary disk10is mounted, through a bearing21, on the cylinder15.

As a further possible modified embodiment of the rotary disk unlocking means, the unlocking circuits18and20could be omitted, and the screw1and screw-nut6assembly could be also used to move away from one another and disengage the ring gears13and14.

Such an embodiment can be advantageously applied in rotary disks or tables10having a horizontal axis or a small size, the movements of which are affected in a less degree by their weight force.

The device according to the present invention can be assembled on rotary table machines, in particular transfer tool machines having either a vertical or a horizontal axis.