DE9208178U1 - Surface grinding machine - Google Patents

Description

TELEPHONE: O711/78OO99S FAX: O7H/78OO996 TELEX: 177111O4Opa3b TELETEX: 2627-7HlO4O=PASB

KOHUER SCHMID -+- PARTIE KT

PATENT ATTORNEY

KÖHLER SCHMID + P. RUPPMANNSTR. 27 D—7OOO STUTTGART &THgr;&Ogr;

19 531 B/pa

Applicant: Ziersch & Baltrusch

Werkzeugmaschinenfabrik GmbH Gotenstrasse 8
7410 Reutlingen 27

Flat grinding machine

The invention relates to a surface grinding machine with a grinding wheel rotating in a holder and a work table that can be moved back and forth relative to the grinding wheel and on which a workpiece to be machined can be fastened, in which a hollow cylinder with a piston rod arranged therein is provided, the holder of the grinding wheel being rigidly connected to the cylinder and the work table being rigidly connected to the piston rod or vice versa, and the relative movement between the grinding wheel and the work table being able to be brought about by a relative movement between the cylinder and the piston rod.

In surface grinding machines of this type with a reciprocating relative movement between the rotating grinding wheel and the workpiece, the latter is usually moved back and forth. In this case, the workpiece to be ground is located on a work table of the grinding machine that can be moved back and forth. Grinding takes place in one direction, while the movement in the opposite direction merely represents the return stroke, during which at least no significant grinding takes place. The relative movement between the grinding wheel and the work table is usually brought about by the holder of the rotating grinding wheel being rigidly connected to a hollow cylinder in which a piston rod can move in the axial direction, to which the work table is in turn rigidly attached. However, the reverse can also be the case: the holder of the grinding machine can be rigidly connected to the movable piston rod and the work table to the cylinder, although this is rarely implemented in practice.

In any case, in the known surface grinding machines, the cylinder is rigidly connected to the base of the surface grinding machine, while the piston rod is moved relative to the machine. A disadvantage of this known design is the large amount of space the machine requires in both axial directions of movement of the piston rod. At both ends of the cylinder, at least enough space must be kept free in the axial direction so that the piston rod does not encounter any obstacles even when fully extended. The piston rod is usually much longer axially than the cylinder, so that the entire space required for a conventional surface grinding machine in the axial direction is

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Direction of the piston rod calculated as the sum of the length of the piston rod and the maximum piston stroke.

The object of the invention is therefore to provide a surface grinding machine with the conventional components and the same movement options with regard to the relative movement between the grinding wheel and the work table, in particular the same maximum piston stroke as in a conventional surface grinding machine, whereby, however, the space requirement in the axial direction of the piston rod should be significantly smaller.

This object is achieved according to the invention in that a continuous piston rod is provided which is fixed in the surface grinding machine, while the cylinder is arranged to be movable relative to the piston rod and thus relative to the surface grinding machine.

The arrangement according to the invention reduces the axial space requirement of the surface grinding machine by the full length of the maximum piston stroke in an astonishingly simple and elegant manner, since the piston rod is now rigidly connected to the machine, while the cylinder can be moved from one end of the piston to the other.

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In a preferred embodiment of the surface grinding machine according to the invention, the piston rod is firmly clamped at both ends in the manner of a tie rod. This means that a piston rod with the same strength requirements can be selected with a relatively smaller wall thickness, which results in weight and material savings.

In a further embodiment of the invention, cylinder heads are provided which are directly attached to the work table, in particular screwed on. As a result, the work table itself acts as a tie rod.

In embodiments of the invention, the cylinder can be a compressed air cylinder. Due to the significantly higher compressibility of gases compared to liquids, the system will react more elastically and flexibly in the event of a sudden strong resistance in the relative movement between the piston rod and the cylinder.

As a rule, however, a hydraulic cylinder is chosen for a grinding machine because this ensures that the machine runs smoothly and quietly. The quasi-incompressible hydraulic fluid also ensures that the intended and set removal depth can be achieved with high precision at any point on the workpiece, even when machining the hardest materials.

In preferred embodiments of the above embodiments,

The compressed air or hydraulic fluid is supplied to the cylinder through the piston rod. This avoids moving connections and thus the risk of material fatigue and resulting defects right from the start.

In another embodiment, the compressed air or hydraulic fluid is controlled from both sides of the cylinder via an external control valve.

A particularly preferred embodiment of the surface grinding machine according to the invention is one in which the piston rod has at least one essentially oblique, preferably milled surface in the area of its two ends, while the middle part of the piston rod is cylindrical in shape. When the cylinder moves into the end position specified by the maximum stroke, this achieves a dampening of the cylinder movement.

A particularly preferred embodiment is one in which the piston rod has a cylindrical shape on the last section before the respective piston end and has a diameter that fits precisely into the bore of a cylinder liner that supports the cylinder. This results in exact retraction into the end position and corresponding braking.

Another advantageous embodiment is one in which a throttle check valve with connection to the compressed air or hydraulic fluid is provided on at least one of the stop-side ends of the cylinder.

between the piston rod and the cylinder, whereby
a smooth approach to the end position with an adjustable defined speed is possible and only at the very end of the
An intercepting impact occurs during the course of the movement.

The invention is described below with reference to the description
The embodiment shown is described and explained in more detail. The information contained in the description and the drawing
Features may be used in other embodiments of the invention individually, by themselves or in groups in any combination.

The drawing shows a longitudinal section through an essential
Part of the surface grinding machine according to the invention, in particular a sectional view of the piston rod and the cylinder.

In the embodiment of a surface grinding machine according to the invention shown, a cylinder sleeve 2 with a cylinder tube 3 and a mounted work table runs on the piston rod 1
4. Between the piston rod 1 on the one hand and the cylinder sleeve 2 or the cylinder tube 3 on the other hand there is a sliding medium which can be compressed air in the case of a pneumatic cylinder or hydraulic oil in the case of a hydraulic cylinder.

While the piston rod 1 is firmly secured at both ends in the manner
of a tie rod and rigidly connected to a base not shown in the drawing, the cylinder liner 2 and the cylinder tube 3 can be moved in the direction of the double arrow

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slide axially back and forth. The workpiece to be machined is usually attached to the work table 4, which is rigidly connected to the cylinder liner 2, while the grinding wheel, which is also not shown in the drawing, is connected to the piston rod 1 or its holder. Conversely, the workpiece could also be fixedly connected to the piston rod, while the grinding wheel moves back and forth with the cylinder liner 2 relative to it.

In the embodiment shown, a cross slide 5 is indicated at the left end at the clamping point of the piston rod 1, which also enables a relative transverse movement perpendicular to the direction of the double arrow and perpendicular to the plane of the drawing.

The figure also shows a connector 6, to which connecting lines for the supply of lubricant, in particular compressed air or hydraulic oil, can be attached. As can be seen from the drawing, the lubricant is fed through an inner bore of the piston rod 1, where it passes through bores 7 into the cavity 8 between the piston rod 1 and the cylinder liner 2 or cylinder tube 3. The usual supply of lubricant via the cylinder was deliberately omitted in the embodiment shown so that no movable supply lines are required, which could show signs of fatigue and result in defects if the cylinder is moved back and forth frequently.

The cavity 8 is sealed against the outside world by a schematically shown scraper ring 9 and a rod seal 10. In addition, O-ring seals 11 are provided, which seal the cylinder liner 2 against the cylinder tube 3 and a structure to which the work table 4 is screwed in the example shown. Furthermore, the relative movement between the cylinder liner 2 and the piston rod 1 is facilitated by a schematically shown plain bearing 13.

At the right end of the piston rod 1 shown in the figure there is a piston head 14 which serves as the right end stop for the cylinder liner 2. A cylindrical piece 15 with a diameter that fits exactly into the bore 16 of the cylinder liner 2 is screwed onto the end of the piston rod 1. However, at the left end of the cylindrical piece 15 there is a slanted surface 17 milled into it, which does not extend all the way to the right end of the cylindrical piece, so that at the extreme right end the cylindrical piece 15 screwed onto the piston rod 1 has a normal cylindrical circumferential surface. If the cylinder liner 2 now moves to the right end of the piston rod 1, it is progressively braked by the increasingly narrowing gap between the cylindrical piece 15 and the cylinder liner 2 due to the slanted surface 17. Because the cylindrical piece 15 has a cylindrical section at its end that fits precisely with the bore 16, the relative movement between the cylinder liner 2 and the piston rod 1 is no longer slowed down when this cylindrical section is passed over. Only when the right end of the cylinder liner 2 hits the

The movement is brought to a complete standstill at the left end of the piston head 14. This enables the system to move into the extreme end position relatively smoothly but still in a defined manner.

In addition, a throttle check valve 18 is provided on the cylinder liner 2, which is connected to the cavity 8 and thus to the lubricant between the piston rod 1 and cylinder 3 or cylinder liner 2. The throttle check valve 1 enables retraction into the extreme end position at an adjustable, defined speed and improves the smooth retraction characteristics.

Claims (10)

19 531 B/pa claims 1. Surface grinding machine with a grinding wheel rotating in a holder and a work table which can be moved back and forth relative to the grinding wheel and on which a workpiece to be machined can be fastened, in which a hollow cylinder with a piston rod arranged therein is provided, wherein the holder of the grinding wheel is rigidly connected to the cylinder and the work table is rigidly connected to the piston rod or vice versa, and wherein the relative movement between the grinding wheel and the work table can be brought about by a relative movement between the cylinder and the piston rod,
characterized, that a continuous piston rod (1) is provided which is fixed in the surface grinding machine, while the cylinder (3) is arranged to be movable relative to the piston rod (1) and thus relative to the surface grinding machine. 2. Surface grinding machine according to claim 1, characterized in that the piston rod (1) is firmly clamped at both ends in the manner of a tie rod. 3. Surface grinding machine according to one of the preceding claims, characterized in that cylinder heads are provided, which are attached directly to the work table, in particular screwed on. 4. Surface grinding machine according to one of the preceding claims, characterized in that the cylinder (3) is a compressed air cylinder, 5. Surface grinding machine according to one of claims 1 to 3, characterized in that the cylinder (3) is a hydraulic cylinder 6. Surface grinding machine according to claim 4 or 5, characterized in that a supply of compressed air or hydraulic fluid to the cylinder (3) is provided through the piston rod (1). 7. Surface grinding machine according to one of claims 4 to 6, characterized in that control of the compressed air or the hydraulic fluid is provided from both sides of the cylinder (3) via an external control valve. 8. Surface grinding machine according to one of the preceding claims, characterized in that the piston rod (1) has at least one essentially oblique, preferably milled surface (17) in the region of its two ends, while it has a cylindrical shape in the middle part. ■:■·■ - 12 - " 9. Surface grinding machine according to claim 8, characterized in that the piston rod (1) has a cylindrical shape again on the last section before the respective piston end and has a diameter that fits exactly into the bore (16) of a cylinder sleeve (2) carrying the cylinders (3). 10. Surface grinding machine according to one of the preceding claims, characterized in that a throttle check valve (18) with a connection to the compressed air or hydraulic fluid is provided between the piston rod (1) and the cylinder (3) on at least one of the stop-side ends of the cylinder (3).