GB2035867A - Planing machines - Google Patents

Abstract

A planing machine having a reciprocatory workpiece supporting table 11 for one or two workpieces W, a tool support assembly carrying one or two tools 26, 27 for working on the workpieces W, the tool support assembly having provision for adjustment vertically and horizontally and a means 16 for monitoring the linear position of the table 11 and for transmitting signals to servo motors 28 to 31 to adjust the tool or tools 26, 27 whereby variable profile machining of the workpiece or workpieces W can be carried out. <IMAGE>

Description

SPECIFICATION Planing machines This invention relates to planing machines particularly for planing long metal workpieces such as rails for railway lines.

A planing machine of the kind with which the invention is concerned has a base with a table mounted on it for linear reciprocation thereon and on which a workpiece can be mounted, there being disposed over the table, at least one tool support on which a tool can be mounted to cut the workpiece which moves past it as the table reciprocates.

The invention is principally concerned with the problem of machining a surface on a workpiece which is non-parallel with the general longitudinal plane of the workpiece. Such a surface may be required, for example, on a rail where it is to form part of a set of points on a railway system. Typically, the surface to be machined provides a tapered portion on a length of rail such as a switch or stock rail.

In known planing machines, for machining long workpieces, such as rails, it is usual to secure the length of rail to the table on an incline suitable to allow machining of the required surface by the straight linear movement of the rail on its table past the tool. This arrangement requires accurate positioning of the rail on the table and this is difficult to achieve.

A further difficulty with known arrangements arises when a surface to be machined is intermediate the ends of the workpieces.

One expedient adopted is to bend a portion of the workpiece so as to accommodate travel of the tool beyond the end of the required surface, with the workpiece mounted at a suitable incline to the direction of travel of the table, the workpiece is bent back again after machining. With this arrangement it may be necessary to complete the machining operation by milling.

The object of this invention is to provide a planing machine of the kind specified which is arranged to machine a workpiece with a surface which is non-parallel with the general longitudinal plane of the workpiece, in an efficient manner, which is not subject to the disadvantages and difficulties associated with known machines.

According to the invention there is provided a planing machine having a base, a workpiece supporting table mounted for linear reciprocation thereon, at least one tool support disposed over the table and arranged to carry a tool to act on a workpiece supported, in use, on the table, and characterised by a means for monitoring the linear position of the table, power means for carrying out adjustment of the tool support in a direction transversely with respect to the direction of linear reciprocation of the table and means for actuating the power means for the tool support adjustment in correlation to the linear position of the table as monitored by said monitoring means.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a general view of a planing machine constructed in accordance with the invention, and Figures 2, 3 and 4 are respective enlarged fragmentary views showing arrangements of tooling for cutting workpieces in different ways.

Fig. 1 illustrates a planing machine which is intended for machining large and particularly long workpieces such as lengths of rail for a railway line. The machine is intended to provide facilities for cutting tapers, recesses and other formations on such workpieces. Figs. 2, 3 and 4 show lengths of rail W cut in three different ways. The rail in Fig. 2 has its upper portion cut away at one side, such cut being of uniformly varying depth towards one end of the length of rail. Fig. 3 shows a similar arrangement in which, however, the foot or base of the rail is cut away. In Fig. 4, furthermore, a rail is shown having a tapered recess formed in its upper surface. The recess may extend over any distance along the rail, as required.

Recesses and cut-outs of these and other patterns can be cut using this machine. In some cases, the taper in relation to the general longitudinal plane of the line may vary over the length of the cut-out or recess and may be of opposite sense in different zones.

As shown in Fig. 1, the machine includes a base 10 which is, in use, secured to a foundation. This carries a table 11 which is mounted for linear reciprocation on the base 10. The stroke of the reciprocation can be varied in a maner which will be described. Reciprocation is achieved by means of a rack 12 secured to the centre of the underneath of the table.

Engaging with his rack is a bull wheel gear 13 mounted on a shaft 14 in the base 10.

The axis of the shaft 14 is perpendicular to the direction of linear reciprocation of the table 11. The shaft 14 is driven through gearing, not shown, by a driving motor 15.

One end of the shaft 14 carries a device 16 which is arranged to monitor the linear position of the table by monitoring the position of rotation of the shaft 14 in relation to a fixed datum.

Connected to the base 10 is a superstructure 17 on which are mounted two tool support assemblies, indicated generally at 18 and 19. These asssemblies comprise vertically adjustable slides 20 and 21 mounted, in turn, upon horizontally adjustable carriages 22 and 23. The slides 20, 21 have formations 24, 25 used for clamping to the slides, respective tools 26, 27, examples of which are illus trated, though it is to be understood that the form of the tooling will vary with the type of cut to be undertaken. Further explanation of this will be given.

Vertical adjustment of the slides 20 and 21 as well as horizontal adjustment of the car riages 22, 23 are carried out by four servo motors, respectively identified by numerals 28, 29, 30, 31, connected to respective shafts 32, 33, 34, 35 mounted on a member 36 which, in turn, is carried on the super structure 17. The servo motors 28, 29 30, 31 are electrically actuated. Rotation of the shafts 32, 33, 34, 35 is converted into linear motion of the respective slides and carriages in a known manner, such as screw and nut mechanism.

A means is provided, indicated generally at 37, which receives electrical signals from the monitoring device 16 attached to the shaft 14 and which, in turn, transmits signals to the servo motors 28, 29, 30, 31. The means 37 can be programmed to actuate the servo motors to achieve adjustment of the slides 20, 21 and of the carriages 22, 23 or any of them in co-relation to the linear position of the table 11. Controls such as thumb wheels on the means 37 are provided to allow such programming.

The table 11 has means (not illustrated) whereon two workpieces W can be mounted.

Two such workpieces are illustrated and their general planes are parallel with the direction of travel of the table in use. When the machine is set up to produce, for example, a tapered cut on the upper portion of each workpiece, as indicated in Fig. 2, reciprocation of the table causes the workpieces to pass the tools 26, 27 and linear movement of the table is accompanied by transverse adjustment of the slides 20, 21 and of the carriage 22, 23, or any of them, to produce the required cut on each of the workpieces. Generally two workpieces are machined to produce symmetrical, asymmetrical or identical cuts upon them by the respective tool support assemblies.

The form of the means 37 which transmits signals from the monitoring device 16 to the servo motors 28, 29, 30, 31 is preferably electronic apparatus to produce the required effects, but a mechanical, hydraulic or other mechanism may be employed with associated monitoring means 16 producing compatible signals.

Since the workpieces are machined when the table is moving only in one of its two directions, it is necessary for the tools to be withdrawn a short distance from the workpieces upon the return stroke. The servo motors are arranged to accomplish this, preferably through the means 37.

Since the cutting of a taper or recess is carried out incrementally, initial stages of machining will take place over a shorter length of the total available travel of the table than during the final stages. This involves automatically changing the position of the point at which machining begins. Such control is preferably achieved in the means 37, though a separate control for actuation of the motor 1 5 may be employed.

Fig. 2 shows the tooling arrangements for a similar cut to that indicated in Fig. 1 arrange ment. Fig. 3 shows a different form of tool 38 mounted so as to cut the base or foot of the workpiece W. This will require only adjustment of the carriage 22 or 23, the slides 20 or 21 remaining stationary.

Fig. 4 illustrates tooling for cutting a recess or taper in the top of the rail workpiece W.

Such a tool 39 is carried immediately above the workpiece. To carry out the necessary machining operation only the slide 20 or 21 is adjusted in accordance with linear travel of the table the carriage 22 or 23 remaining fixed.

Compound tapers can also be produced by simultaneous motion of slides 20, 22 and of slides 21, 23 in accordance with linear travel of the table.

Facilities are also provided for fast travel of the tool support assemblies in appropriate directions, this being necessary for setting up the machine. Such fast travel is contrasted with the normal more slow speed of travel of these parts for adjustment during the machining operation.

Claims (6)

1. A planing machine having a base, a workpiece supporting table mounted for linear reciprocation thereon, at least one tool support disposed over the table and arranged to carry a tool to act on a workpiece supported, in use, on the table, and characterised by a means for monitoring the linear position of the table, power means for carrying out adjustment of the tool support in a direction transversely with respect to the direction of linear reciprocation of the table and means for actuating the power means for the tool support adjustment in correlation to the linear position of the table as monitored by said monitoring means.

2. A planing machine as claimed in claim 1 in which monitoring means is arranged to transmit an electrical signal to said power means, the monitoring means being arranged to monitor rotation of a shaft carrying drive means for the said table.

3. A planing machine as claimed in claim 2 in which the monitoring means is arranged to monitor rotation of said shaft in relation to a fixed datum.

4. A planing machine as claimed in any one of the preceding claims in which the tool support has provision for adjustment in two mutually perpendicular directions, both of which are transverse to the direction of reci procation of the table, said adjustments being carried out by servo motors which are arranged to be actuated upon receipt of signals from said monitoring means.

5. A planing machine as claimed in any one of the preceding claims wherein the table is adapted to support two workpieces simultaneously and the tool support has provision for two tools for working thereon respectively, the tool support adjustment being arranged to adjust said two tools.

6. A planing machine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.