GB2029287A

GB2029287A - An arrangement for limiting the deflection of a horizontally extensible slide of a machine

Info

Publication number: GB2029287A
Application number: GB7928886A
Authority: GB
Original assignee: Skoda op; Skoda np
Current assignee: Skoda op; Skoda np
Priority date: 1978-09-04
Filing date: 1979-08-20
Publication date: 1980-03-19
Also published as: DE2933357C2; FR2434673A3; IT7925436A0; DE2933357A1; JPS5537296A; IT1165298B; GB2029287B; CS201325B1; FR2434673B3

Abstract

A horizontally extensible slide (3) is accommodated in an arm (2) on a support column 1, and is supported by a beam 4. The support beam 4 is preferably formed with two inclined surfaces 13, 14 each resting on a respective roller (7, 8) of a support system having a counterweight 12. <IMAGE>

Description

SPECIFICATION An arrangement for limiting the deflection and tilting of a horizontally extensible slide of a machine The invention relates to an arrangement for limiting the deflection and tilting of a horizontally extensible slide of a machine, particularly of a milling machine or a boring machine having a horizontally extensible spindle.

In single stand milling machines and boring machines having a horizontally extensible spindle with a slide in the shape of a sliding spindle or of an extensible supporting spindle sleeve, changes of the position of a tool in case of a horizontal extension of the slide from the arm accommodating the slide have undesirable consequences. A substantial influence on the thus caused innaccuracy has the deflection of the slide due to its own weight and the deformation and tilting of the arm in its support on the stand, caused by changes of the position of its centre of gravity. In order to reduce these unfavourable influences, the slide with the arm are balanced by means of cables or chains so that they are suspended on two suspensions transmitting the variable load depending on the extension of the slide from the arm.This arrangement limits the tilting of the arm, it however does not prevent its deformation and does not balance the slide, but deforms it so that its extremity with the working tool moves as much as possible in a horizontal plane the face surface of the slide is however not in a vertical plane. According to another known arrangement pull rods and struts with a variably acting force are provided in the longitudinal direction of the slide, eliminating the deflection of the slide in dependence on the extension thereof.

All these arrangements for limiting the deflection of the slide represent however an unwelcomed load to its guiding surfaces and deform the guiding surfaces for the slide in the spindle. They are either less efficient or costly.

It is an object of this invention to substantially reduce the deflection and tilting of a horizontally extensible slide of machines, for instance of a milling machine or a boring machine having a horizontally extensible spindle, where the slide is designed as a sliding spindle or as an extensible supporting spindle sleeve, said sliding shoe being supported by at least one supporting beam, which is with respect to the slide either stationary or slidable, supporting it in any extended position near its ends at points of support. Suitably shaped surfaces for supporting rollers of supporting places are provided on the supporting beam, connected by balancing cables with a source of a balancing force, for instance with a counterweight.

According to another embodiment the supporting beam is supported in suspension joints by balancing cables connected with a source of a balancing force, for instance with a counterweight.

The arrangement according to this invention enables to substantially reduce the unfavourable influences of the weight of the slide on the accuracy of the machine with respect to existing methods of balancing the slide and its supporting in the arm by relieving the guiding surfaces of the slide, limiting the deformation of the slide and the tilting of the slide for vertical shifting.

These advantages are achieved by supporting the slide by at least one supportingteam, supporting the slide at two points of support so as to obtain a minimum deflection. In the course of extension of the slide from the arm body, the supporting beam is shifted together with the slide. Steady forces acting on the supporting beam from the slide are in any extended position of the slide in equilibrium with forces acting on the supporting beam from a balancing device for balancing the slide. The equilibrium of forces on the supporting beam is obtained automatically by different embodiments of the balancing device.

When balancing the slide by a counterweight by means a front and rear balancing cable or chain and the respective rollers situated on the upper part of the machine stand, where the balancing cables are with their first ends suspended as far as possible at a single place of the counterweight and with their other ends to the front and rear suspension, these suspensions are capable to transmit the force to the suspension beam either directly or by way of a balancing beam.

In the first case the supporting beam has suitably formed surfaces, along which in case of extension of the slide and thus also of the supporting beam, supporting rollers of the front and rear suspensions are rolling. If the suspensions are mutually so far, that at any extension of the slide, its centre of gravity remains between these suspensions, Nbe forces in the suspension cables, which are shortened or prolonged in order that the slide maintains its horizontal position, will vary in case of extension of the slide due to suitably formed surfaces of the supporting beams.

In the second case, the supporting beam is between the points of support where it supports the slide, provided with a supporting roller so that it supports the whole unit represented by the supporting beam and the slide below its centre of gravity. A balancing force is transmitted to the supporting roller of the supporting beam by means of a balancing beam, at the ends of which ends of balancing cables are fixed in joints. The balancing beam is not shifted when the slide is extended, but solely is turned around the supporting roller in dependence on the extension of the slide. Thus the ratio of forces due to the counterweight in the front and rear balancing cable is varied automatically.

An arrangement according to the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings,-in which: Fig. 1 is a front elevation of a vertically displaceable arm, in section, with a spindle sleeve supported by two supporting beams having surfaces, along which rollers of suspensions may roll and the upper part of a stand of a horizontal boring machine, Fig. 2 is a side elevation to Figure 1 with parts in section, Fig. 3 corresponds to Fig. 1 but with the spindle sleeve extended, Fig. 4, 5 and 6 are simiiar views as in Fig. 1,2 and 3 with an additional device is fixed on the front end of the spindle sleeve, Fig. 7 is a front elevation of a vertically displaceable arm, in section, with a spindle sleeve supported by two supporting beams provided with supporting rollers for rolling along balancing beams and the upper part of a horizontal boring machine, Fig. 8 is a side elevation to Fig. 7 with parts in section, and Fig.9 corresponds to Fig. 7 but with the spindle sleeve extended.

With reference to the drawings, an arm 2 is vertically displaceable on a stand 1, in which arm 2 an extensible slide, 3 which may be in the shape of a spindle sleeve, is slidably arranged. The slide 3 is at each side supported by a supporting beam 4 or 19 at points A and B of support. If necessary, for instance when the slide 3 is being stressed by the weight of an additional device 17, the supporting beams 4 or 19 may be displaced in the direction S by means of a toothed rack 1 6 and pinion 15. The supporting beams 4 are provided with suitably formed surfaces 13 and 14, along which supporting rollers 7 of the front suspension 5 and supporting rollers 8 of the rear suspension 6 can roll. The front suspension 5 is connected to one end of a balancing cable 10.The balancing cable TCT, is guided over rollers ofa balanc#ing device, situated in the upper part of the stand 1, and is connected mt C to a counterweight 12. The rear suspension 6 is connected to one end of a balancing cable 11. The balancing cable 11 is also guided over rollers of the balancing device and is connected to the counterweight 12, possibly also at C as the balancing cable 10. If an additional device 1 7 is fixed to the slide 3, the weight Q of the slide 3 increased by the weight Q, of the additional device 17 is balanced by the counterweight 1 2 of the weight G to which a counterweight 18 of the weight G, is fixed.In that case the supporting beams 4 are shifted with respect to the slide 3 in the direction S so far, that the slide 3 supported at points A, and B, and loaded by the additional device 17, is supported as far as it is possible so that a minimum deflection occurs.

Fig. 7 shows the supporting of the slide 3 by two supporting beams 19 provided with supporting rollers 20. When the slide 3 is extended, the supporting rollers 20 move along suitably formed rolling surfaces 27 and 28 of the balancing beams 21. The balancing beams 21 are connected by way of joints 25 of the front suspension 22 and a balancing cable 10 and by means of joints 26 of the rear suspension 23 and a balancing cable 11 at C to the counterweight 12. The supporting beams 19 can, similarly as the supporting beams 4 in Fig. 1, change their position with respect to the slide in the direction S. When the slide 3 is extended, only the inclination of the balancing beams 21 is changed.

Undesirable shifting of the balancing beams 21 can be for instance prevented by providing in each balancing beam 21 an elongate hole 24, into which engages a bolt fixed to the arm 2.

One of the balancing cables 10 and 11, or both, are provided with a tensioning device 9. The lengths of the balancing cables 10 and 11 are adjusted by the tensioning device 9 and thus are also adjusted the forces acting over said cables so that the resulting force of forces acting in the balancing cables 10 and 11 at any position of the slide 3 would pass through its centre of gravity and have the same direction, but an opposite sense than the force due to the weight of the slide 3.

The arrangement according to this invention is particularly designed for balancing and for limiting the deflection and tilting of horizontally extensible slides of machine tools. In horizontal milling cutters and boring machines, sliding spindles and spindle sleeves, serving as support of the boring spindle, can be balanced by means of this arrangement and particularly at those arrangements, where different additional devices are fixed to a horizontally extensible sliding spindle.

The arrangement according to this invention can be also applied on drawing and measuring machines, industrial robots, presses and machines for the building industry.

Claims

1. An arrangement for limiting the deflection and tilting of a horizontally extensible slide of a machine, wherein the slide is supported by at least one supporting beam, supporting the slide in any extended position near its extremities at points of support.

2. An arrangement according to Claim 1 wherein the slide is arranged as a sliding spindle or an extensible supporting spindle sleeve.

3. An arrangement according to Claim 1 or Claim 2 wherein the or each supporting beam is provided with suitably formed surfaces for resting on rollers which support the beam and are connected to a source of balancing force.

4. An arrangement according to Claim 3 wherein each roller is carried by a suspension connected to the source of balancing force by a cable.

5. An arrangement according to Claim 1 wherein the or each supporting beam is provided with a supporting roller resting against a balancing beam, the latter being connected to a source of balancing force.

6. An arrangement according to Claim 5 wherein each balancing beam is attached at suspension joints to suspensions, each suspension being connected to the source of balancing force by a cable.

7. An arrangement according to Claim 4 or 6 wherein at least one of the cables is provided with a tensioning device for the adjustment of its length.

8. An arrangement according to any one of Claims 2 to 7 wherein the source of the balancing force is a counterweight.

9. An arrangement for limiting the deflection and tilting of a horizontally extensible slide of a machine, constructed, arranged and adapted to operate substantially as herein described with reference to, and as shown in, Figures 1 to 3, or Figures 4 to 6, or Figures 7 to 9 of the accompanying drawings.

10. A product made by a machine tool incorporating an arrangement according to aJnt one of Claims 1 to 9.