DE8334163U1 - Screw press with overload protection - Google Patents

Description

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overload protection for screw presses by limiting the in torque introduced into the spindles, the spindle nut being rotatably mounted.

The innovation relates to an overload protection for Screw pressing by limiting the torque introduced into the spindle, whereby the spindle nut is rotatably mounted is.

In screw presses, the full energy of the flywheel is released when the workpiece is hit.

Since with screw presses, especially during forging, the flywheel energy is greater than the press absorbs some kind of overload protection must be implemented.

For example, hydraulic overload protection devices are known (DE-PS 16 27 940), in which a complex construction is required by safeguarding the full pressing force.

It is also known to use a friction clutch as a torque limiter to be provided in the flywheel or in the spindle nut (DE-OS 21 28 338). Such a torque limitation is <j however, very imprecise, as the friction factor depends on many influences (temperatures, dirt, oil).

This is where the present innovation comes in and also deals with an overload protection device for screw presses, in which, however, the disadvantages that occur with the known overload protection devices are largely avoided ₍ .

This is achieved with an overload protection of the input described embodiment in that the spindle nut, when arranged in the press ram, is connected to the same via an interposed one hydraulic piston-cylinder units or resilient elements.

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A particularly advantageous embodiment of this overload protection is characterized in that the spindle nut is fixed in a non-rotatable manner in an upper part of the tappet, which in turn is rotatably mounted in the press ram and see on the press ram via interposed hydraulic piston-cylinder ■ Supports units or resilient elements.

So it is also possible, according to the innovation, that the spindle nut when arranged in the press body on the same via interposed hydraulic piston-cylinder units or resilient elements.

According to the innovation, the spindle nut rotates when the set torque is exceeded and thus the corresponding pressing force compared to the press ram with the excess work capacity of the flywheel in simple way is either stored in the supporting elements or destroyed in the supporting members.

The innovation is based on a drawing, which is any Illustrates embodiment, explained in more detail.

Bs show:

Fig. 1

Fig. 2

a screw press in side view longitudinally sectioned and

a section along "the line A-B of FIG. 1.

In the press body 1 there is a spindle 2 between a roller bearing 3 and a thrust bearing 4 rotatably mounted.

Each SpindeliButter 6 can be rotated in the press ram 5 mounted ram upper part 7 and secured against rotation. This spindle nut 6 stands with the thread 18 of the

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Spindle 2 in engagement. The upper part 7 of the ram is supported by arms 7a and pistons 8 as well as oil pads 19 in the cylinders 9 g <> 7en on the press ram 5. The oil chambers 19 of the cylinders 9 are filled by a pump 11 up to the preselected pressure on the pressure switch 12. The overload valves 10 are expediently attached directly to the cylinders 9. '

In the upper starting position of the press, the flywheel 13 is electrically «pneumatically or hydraulically accelerated and charged with kinetic energy. The flywheel 13 and the The threaded spindle 2 rotates in the direction of the arrow 17. As a result, the spindle nut 6 and the upper part 7 of the tappet move and the press ram 5 downwards until the upper tool 14 hits the workpiece 15 in the lower tool part 16. the The energy stored in the flywheel 13 is transferred to the workpiece, as a result of which it is transformed. The press ram 5 now moves up again and is brought to a standstill in the upper position.

When the workpiece 15 is deformed, a force is generated corresponding to the deformation resistance of the workpiece. Likewise A torque that acts on the spindle 2 and, via the spindle nut 6, the upper part of the tappet is proportional to this force 7, the piston 8, the oil pad 19, the cylinder 9 and the press ram 5 is taken up by the press body 1.

In all forming processes in which the forming force is below the permissible pressing force of the press, there is no relative movement between the pistons 8 and the cylinders 9. the The press behaves like all presses, & those who do Spindle nut 6 is firmly connected to the press ram 5.

If the permissible pressing force is exceeded, the in the Overload valves 10 set pressure exceeded, whereby Oil is sprayed out of the cylinders 9 via the overload valves 10. This removes the excess energy from the flywheel is consumed and is no longer available for a further dangerous build-up of strength in the press.

A relative movement then occurs between the pistons 8 and the cylinders 9, i.e. the spindle nut 6 rotates a small angle with respect to the press ram 5, whereby the advance of the press ram 5 and the upper tool 14 to the lower tool 16 is stopped. Then it does not find any further increase in force takes place.

This relative movement between the piston 8 and the cylinder is queried by a travel sensor or limit switch and the "Overload" displayed on the operator panel.

After each response of the device, the pressure in the system drops, after which the pump 11 fills the entire system again. These Pump 11 also serves to compensate for any leakage losses. The press is ready for operation again when the pressure switch 12 again indicates pressure and the pistons 8 have returned to their original position.

To prevent the overload protection from responding, this must be the case The work capacity of the flywheel 13 can be matched to the deformation work of the workpiece 15. Is the working capacity of the Flywheel 13 is set too high, i.e. when the workpiece and the press are not able to use the one stored in the flywheel 13 The remaining energy of the flywheel is used up in the form of work or permissible spring work 13 consumed in this overload device, whereby overloading of the press can be avoided.

Instead of the overload valve piston-cylinder-combination may also be hydraulic, pneumatic, mechanical barren Federeiemente be installed as a support between the arms' Yes of the plunger top portion 7 and the press ram 5, which is not shown. The excess energy is then stored in these spring elements.

The overload device described can be used for screw presses of all types can be used, regardless of whether the

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Spindle nut 6 in the press ram S or in the press body 1 is located. In designs in which the spindle nut 6 is located in the press body 1, the secured support is then to be arranged between the threaded nut 6 and the press body 1.

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Claims (3)

1. ^ screw press with overload protection ^ by limiting the torque introduced into the spindle, wherein the spindle nut is rotatably mounted, characterized in that that the spindle nut (6), when arranged in the press ram (5), is connected to the same via an interposed one hydraulic piston-cylinder units (8, 9) or resilient elements. 2. Screw press with overload protection by limiting the torque introduced into the spindle, wherein the spindle nut is rotatably mounted, characterized in that that the spindle nut (6) when arranged in the press body on the same via interposed hydraulic piston-cylinder units (8, 9) or supports resilient elements. 3. Screw press according to claim 1, characterized in that that the spindle nut (6) is fixed non-rotatably in a ram upper part (7), which in turn is rotatably mounted in the press ram (5) and is located on the Press ram (5) via interposed hydraulic piston-cylinder units (8, 9) or supports resilient elements. • t *