GB2028193A

GB2028193A - Centreless grinding machines

Info

Publication number: GB2028193A
Application number: GB7929497A
Authority: GB
Original assignee: Werkzeugmaschinenkombinat 7 Oktober VEB
Current assignee: Werkzeugmaschinenkombinat 7 Oktober VEB
Priority date: 1978-08-25
Filing date: 1979-08-24
Publication date: 1980-03-05
Also published as: FR2434008A1; DE2924278A1; DD138287B1; IT1162378B; SU1014687A1; DD138287A1; IT7950090A0; GB2028193B

Abstract

A centreless grinding machine has a control member 5 which is rotatably mounted in a casing 6 and which effects a long stroke during plunge-cut grinding. A workpiece rest 2 is located in a grinding gap which is open at the top. A control member carriage 10 supports the control member casing 6. The carriage 10 and the casing 6 are interconnected via a pivot joint 7 and a piston drive 9, such that the casing 6 can be pivoted about an axis extending transversely to the direction of the plunge-cut feed, thereby to provide the long stroke movement. A fixed or adjustable abutment 8 is provided on the carriage 10 to limit the stroke movement of the casing 6 with the control member 5 towards the workpiece 3 and the grinding member 1. In another aspect of the invention the carriage 10 and casing 6 are interconnected slidingly via an inclined guide and a piston drive, such that the casing 6 can be displaced away from the workpiece rest 2. <IMAGE>

Description

SPECIFICATION Centreless grinding machines This invention relates to a centreless grinding machine having a control member which effects a long stroke during plunge-cut grinding.

In centreless grinding machines for plungecut grinding having a grinding gap open at the top, it is known to withdrawn the control member, that is the control wheel, from the workpiece rest by means of a long stroke, so that time can be saved by enabling the ground workpiece to drop out of the grinding gap between the workpiece rest and the control member.

When the grinding gap is closed, it is recharged with the workpiece. The long stroke is effected in accordance with the disclosure in the German Offenlegungsschrift No. 25 29 885.

In centreless grinding machines having a fixed workpiece rest, the control member carriage is moved on the machine bed or on a pivoting carriage. The grinding member, that is the grinding wheel, carriage effects the plunge-cut movement with quick traverse and in-feed and also the feed for controlling the dimensions on the workpiece.

In machines having a fixed grinding spindle bearing, the control member carriage is moved on an intermediate carriage supporting the workpiece rest. The intermediate carriage either effects only the feed movement for correcting the dimensions on the workpiece, the control member carriage effecting the long stroke movement, the quick traverse and the in-feed, with the feed carriage in a fixed position, or the control member carriage effects only the long stroke movement, and the intermediate carriage in a fixed position with the control member carriage effects the quick traverse, the in-feed and the feed movement for controlling the workpiece dimensions.

A disadvantage shared by the known constructions is the relatively large mass of the control member carriage, which for reasons of productivity must have a high acceleration and retardation, and usually bears or entrains the control member casing, with spindle, bearing and control member, and also the truing device, drives, in-feed devices, and any charging devices. The resulting forces have a negative effect on the high accuracies and stability of manufacture demanded of centreless grinding machines. They result in undesirable dynamic loadings and increased wear on the carriage drives and positioning means.

The known constructions call for special drives, more particularly to enable the control member carriage to make the long stroke on the intermediate carriage. If, for example, a hydraulic piston drive is used for this pupose which acts on the control member carriage from the intermediate carriage, constructions of the carriages are required which differ considerably from the design of the machines without long stroke. If the drive for the long stroke is to act from the machine frame on the control member carriage and the control member carriage and intermediate carriage in a fixed position in relation to one another effects the quick traverse, the in-feed and the feed, additional drives, abutment means, positioning and control of the intermediate carriage are required, and these cause expensive changes in existing constructional members and complicate manufacture.

If due to the absence of technical means the long stroke, quick traverse, in-feed and if necessary feed are effected from the control member carriage on a stationary intermediate carriage, the workpiece is also displaced in the radial direction along the workpiece rest while it is being machined.

The main disadvantages are the constant change in workpiece height during grinding and feed, constant changes in the position of the workpiece in relation to the workpiece rest and the charging device, and also undesirable wear, more particularly on the workpiece rest.

It is an object of the invention to enable workpieces to be removed from the grinding gap of centreless grinding machines having means for effecting a stroke in a rational manner and with the minimum of extra time.

Another object is to reduce the dynamic loading of the machine, so that the attainable accuracies on the workpiece and stability of manufacture are not adversely affected, and premature wear on the carriage drives and positioning means is avoided. A further object of the invention is to enable the long stroke to be effected at choice, without considerable adjustments having to be made to the design of serially produced structural members of the machine.

The technical problem which the invention aims at solving is to provide a centreless grinding machine having a long stroke means, wherein the mass of the structural members moved during the long stroke is reduced in comparison to known constructions, and the long stroke can be effected without the adjustment of the control member carriage, and independently of the existing drives for the infeed, quick traverse and feed, and also independently of their adjusting and positioning means.

The invention also aims at making possible the optimum superimposition of the quick traverse and long stroke, and to ensure fixed workpiece positioning during the charging of the grinding gap with the workpiece and during grinding.

Accordingly, the present invention consists in a centreless grinding machine having a control member which is mounted in a casing and which effects a long stroke during plungecut grinding, a workpiece rest located in a grinding gap open at-the top and a control member- carriage which carries the control member casing receiving the control member spindle bearing, characterised in-that the control member carriage and the control member casing are interconnected via a pivot joint and a piston drive such that the control member casing is pivotable about an axis extending transversely of the direction of the plunge-cut feed and that a fixed or adjustable abutment is provided on said carriage for the- control member casing.

The present invention also consists in a centreless grinding machine having a control member which is mounted in a casing and which effects a long stroke during plunge-cut grinding, a workpiece rest located in a- grinding gap open at the top, and a control member carriage which carries the control member casing receiving the control member spindle bearing, characterised in that the control member casing and the control member carriage are interconnected via an inclined guide and a piston drive, such that the control member casing is slidable away from the workpiece rest, and that a fixed or adjustable abutment is provided on said carriage for the control member casing.The piston drive produces the pivoting or sliding- movement which effects the long stroke and ensures that the control member casing bears against a fixed or adjustable abutment. The pivot joint may be- disposed on the top or bottom end of the control member casing.

In order that the invention may be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example two embodiments thereof, and in which:~ Figures 1 and 2 shows respective embodiments of centreless grinding machines in accordance with the invention.

Fig. 1 of the drawings shows a centreless grinding machine having a fixed spindle bearing of a grinding wheel 1 on a machine frame 13. A carriage 12, pivotable about a pin 16, carries an interm-ediate carriage 11. Attached to the intermediate carriage 11 by way of a support 4 is a workpiece rest 2 for a workpiece 3. The support 4 can be pivoted, for example, on the intermediate carriage 11 coaxially about a vertical pin (not shown). A control wheel carriage 10 is arranged displaceably, in relation to the support 4, on the intermediate carriage 11.

The control wheel carriage 10 carries a control wheel casing 6 which receives a spindle bearing with the control wheel 5. The control wheel casing 6 is connected by means of a pivot joint 7 and a hydraulic drive 9 to the control wheel carriage 10. An abutment 8 for the control wheel casing 6 is attached to the control wheel carriage 10.

A bracket 17 is disposed between the control wheel casing 6 and the control wheel carriage 10, the bracket 17 being connected by means of joint 7 and piston drive 9 to the control wheel carriage 10 and retained by the adjustable or fixed abutment 8.

The bracket 17 carries known devices for the axial and vertical adjustment and securing of the control wheel casing 6, which can pivot around pin 18. The pin 18 is movable, for example, with a cross-guide.

Fig. 2 illustrates a construction in which a control wheel casing 6' is connected via an inclined guide 14 to the control wheel carriage 10. A piston drive 9' displaces the control wheel casing 6' from the control wheel carriage- 1 0 against an adjustable or fixed abutment 15. The control wheel casing 6' is so attached by known means, for example, a cross-guide, on a carriage of a guide 14, that the casing can be adjusted and pivoted in the axial direction. A pin 19 can be moved with the cross-guide.

The control wheel casing 6,6' is urged by the drive 9,9' against the abutment 8,15.

Only during long stroke is the control wheel casing 6,6' (Figs. 1 and 2) withdrawn from the workpiece rest 2, and the workpieces 3 can conveniently drop away between the workpiece rest 2 and the control wheel 5 on to conveying devices (not shown).

Claims

1. A centreless grinding machine having a control member which is mounted in a casing and which effects a long stroke during plungecut grinding, a workpiece rest located in a grinding gap open at the top and a control member carriage which carries the control member casing receiving the control member spindle bearing, characterised in that the control member carriage and the control member casing are interconnected via a pivot joint and a piston drive, such that the control member casing is pivotable about an axis extending transversely of the direction of the plunge-cut feed, and that a fixed or adjustable abutment is provided on said carriage for the control member casing.

2. A centreless grinding machine as claimed in claim 1, wherein the pivot joint is arranged at the top or bottom end of the control member casing adjacent said carriage.

3. A centreless grinding machine having a control member which is mounted in a casing and which effects a long stroke during plungecut grinding, a workpiece rest located in a grinding gap open at the top, and a control member carriage which carries the control member casing receiving the control member spindle bearing, characterised in that the control member casing and the control member carriage are interconnected via an inclined guide and a piston drive, such that the control member casing is slidable away from the workpiece rest, and that a fixed or adjustable abutment is provided on said carriage for the control member casing.

4. A centreless grinding machine, substantially as herein described with reference to and as shown in Fig. 1 or Fig. 2 of the accompanying drawings.