GB2080908A - Guard means for a workpiece transfer system - Google Patents

Abstract

A machine tool work transfer system 16 includes guard means 28 adapted to co-operate with further guard means 15 around a machining station 11 to fully enclose a working area 11, the guard means 28 being associated with the workpiece transfer system 15 and both being mounted for rotational movement of a workpiece (not shown) between an access station and the machining station 11, the guard means 28 providing a barrier to separate said stations. The guard means 28 has resilient end strips 30 forming splash guards. <IMAGE>

Description

SPECIFICATION Guard means for a workpiece transfer system This invention relates to guards for machine tools such as milling machines, machining centres and the like during the use of which machines workpieces are capable of being automatically interchanged between a station where access is possible (hereinafter referred to as an access station) and a station where machining is possible (hereinafter referred to as a working station).

At a working station the workpiece must be 4within a guarded enclosure and it is also so positioned that it is capable of being operated upon by the machine. When a workpiece is at access station, which may be outside the guarded enclosure, it is so positioned that it may be removed and anotherworkpiece placed in position to be subsequently moved to the working station for a machining operation.

The workpiece is mounted on a support means for movement between the access station and the working station. This support may be a pallet, jig or other holding means.

In order for the guard means to provide adequate protection for a machine operator without impairing the function of the machine in addition to being not unduly cumbersome or expensive, the guard means has to be designed with the following parameters in mind: 1. the guard should be of relatively simple design; 2. the guard should permit access to the workpiece when the workpiece is in an access station and access to the workpiece by the machine when the workpiece is in a working station; 3. the guard should be operable to prevent pieces of machine material and/or coolant resulting from a machining operation from being projected out of the guarded area.

It is an object of the present invention to provide a workpiece transfer system in or for a machine tool which incorporates guard means adapted to achieve at least some of the above mentioned desiderata.

According to the present invention we provide in or for a machine tool a workpiece transfer system adapted to transfer a workpiece between ran access station and a working station, said system comprising a pair of workpiece supports mounted for rotational movement about a common axis, guard means situated between said supports and mounted for movement about said rotational axis, the arrangement being such that when one support is in a working station, the other is in the access station, said guard providing a barrier to separate said stations.

Preferably the said workpiece supports and said guard means are mounted on a common member for rotational movement about said axis, conveniently the workpiece supports are mounted diametrically opposite each other relative to said rotational axis.

Preferably the guard means cooperates with further guard means when one of said supports is in the working station to provide a substantially continuous barrier around the working station.

The guard means may have a pair of substantially vertical guard edges disposed on opposite sides of said rotational axis, which edges are adapted to cooperate with saidfurther guard means. Conveniently said substantially vertical guard edges may themselves be flexible or be provided with flexible members which flexible members cooperate with said further guard means to substantially seal from the exterior the guarded working station.

Preferably the guard means extends radially from said rotational axis at least in one direction by a distance substantially the same as the distance of the radially outermost part of the workpiece support from said rotational axis in order that said guard means is of a sufficient dimension to co-operate with said further guard means while the opening provided in said further guard means is sufficient to allow for rotation of said support means to move the workpiece supports between their access station and their working station.

Preferably, the workpiece supports are mounted in a manner so that movement, preferably linear movement, relative to said rotational axis is also possible and means may be provided for causing said movement.

Preferably the guard means is arranged in a plane, which plane also contains the rotational axis, and which lies at an angle relative to the axis along which said supports may be moved during their movement towards and away from the rotational axis. Such an oblique attitude of the guard means relative to the movement axes relative to the rotational axis ensure full access to the supports and hence workpieces by an operator, for example when they are in their access station, and by a machine when they are in their working station. Preferably each of said support means comprises a rectangular pallet, each carried by a member mounted for rotation about said rotational axis, said member also carrying said guard means.

One embodiment of the present invention will now be described in detail by way of example only, with reference to the accompanying drawing wherein: FIGURE 1 is a plan view of a machine tool embodying the work transfer system of the present invention; FIGURE 2 is a sectional view of the transfer system shown in Figure 1.

Referring first to Figure 1, a machine tool 10 is depicted having a machining zone 11 wherein the machine cutter 12 may interact with the positively located workpiece support in the form of a pallet 13 carried on a machine registering means, depicted as a slideway 14, along which slideway 14 the workpiece may be moved in a linear manner relative to the rotational axis 18.

The machining zone 11 is substantially enclosed by a machine guard comprising guard means 28 and further guard means, part of which is shown at 15.

The machine tool 10 employs a rotary pallet shuttle assembly 1 6 for alternately transmitting a finished workpiece (not shown) out of the working station, i.e. machining zone 11, and a rough workpiece into the machining zone 11.

The pallet shuttle assembly generally indicated at 16 comprises a stationary base 17 having rotationally mounted thereon a rotatable member 19 adapted for rotation about an axis 18. The rotatable member 19 comprises a frame-like member having a plurality of slideways 20 onto each of which is mounted a pallet 13,21, which pallets 13, 21 are mounted for linear moving along the slideway 20.

The rotatable member 19 is shown having two slideways 20 each canting a pallet 13, 21 respectively.

The pallets 13, 21 are substantially identical to one another and upon which, in use of the transfer system, would be located respective workpieces.

The pallets 13, 21 are diametrically disposed about the rotational axis 18 and so positioned that the axis of their respective slideways are parallel to one another such that linear movement is possible along the respective slideway 20 along respective linear transfer axes 22,23 towards and away from the pallet shuttle assembly 1 6.

A pair of cylinders 24 are affixed to the rotatable member 19 and a piston rod 25 extending from the cylinder 24 may be coupled through a suitable clamp 26 to move the pallets 13, 21 along the linear transfer axes 22, 23 when desired.

The pallet 21, lying outside the guarded machining station, is considered to be at an access station wherein an operator may interact with a workpiece on the pallet 21 for a variety of purposes such as location and inspection or possibly removal. The pallet shuttle assembly 16 is positioned within an opening 27 in the further guard means 15 around the machine and the opening 27 is closed, when one of the pallet is in a machining station, by a substantially planar guard means 28 which is secured to the rotatable member 19, and is rotatable about the axis 18.

The guard means 28, hereinafter referred to as a guard member, lies at an oblique angle to the linear transfer axes 22 and 23 of the rotatable member 1 6 so that it passes across a corner 29 of a respective rectangular pallet 21, thereby permitting substantially full access to at least four sides2la,21b,21c,2ldofthepallet2l and workpiece situated thereon.

The guard member 28 has a strip of resilient material 30, which material may be elastomeric at each of its vertical edges 28a, 28h, which material may contact with the further guard means 15 substantially enclose the machining zone 11 and prevent the overspray of coolant and projection out of the machining area of strips of material caused by a machining operation.

After a machining operation, the pallet 13 in the machining zone 11 is withdrawn by the piston rod 25 to the position shown in dotted outline for a subsequent interchange of pellets At such interchange time, the rotatable member 19 is rotated through 1 800 about the axis 18 to bring the pallet 21 into alignment with the machining zone 11, and the machining zone pallet 13 to the access station. At such interchange time, the machine guard opening 27 is opening and when the interchange is complete, and the pallet 21 is in the machining station, the opening 27 wijl once again be closed by the guard member 28.

Referring to Figure 2, the base member 17 is shown as being a substantially vertical tube i assembly 31 having a lowermost plate 32 which is provided with adjustable floor supports 33. The vertical tube assembly 31 has a bearing systeen 34 to journal the spindle 35 of the rotatable member 19. The rotatable member 29 is provided with rotary drive gears 36, 37 and a motor assembly 38 to accomplish the rotation and interchange of the pallets 13 and 21.

The uppermost surface 39 of the rotatable member 19 carries a plurality of slideways for slidably carrying the pallets 21 shown in bold outline, and the pallet 13 shown in dotted outline.

The substantially vertical planar guard member 28 has an angled top edge 40 to add strength and stiffness to the guard member, and a bottom edge 41 which is secured to the rotatable rnember 19 by screws 42. The elastomeric seaiih-g strip 30 is secured to the vertical edges 28a, 286 of the guard member 28 by fasteners 43.

The elastomeric sealing strip 30 is shown coacting with the further guard means 16 provided around the machine so as to effeetively seal the opening 27.

Claims (13)

1. In or for a machine tool a workpiece transfer system adapted to transfer a workplace between an access station and a working station, said system comprising a pair of workpiece supports mounted for rotational movement about a common axis, guard means situated between said supports and mounted for movement about said rotational axis, the arrangement being such that when one support is in a working station, the other is in the access station, said guard providing a barrier to separate said stations,

2. A workpiece transfer system as claimed i;n Claim 1 wherein said work supports and said guard means are mounted on a common member for rotational movement about said axis.

3. A workpiece transfer system as claimed in Claim 1 or Claim 2 wherein said workpiece supports are mounted diametrically opposite each other relative to said rotational axis

4. A workpiece transfer system as claimed in any one of the preceding claims wherein said guard means co-operates with further guard means when one of said supports is in a working station.

5. A workplece transfer system as claimed in Claim 4 wherein said guard nieans has a pair of substantially vertical guard edges disposed on opposite sides of said rotational axis, which edges are adapted to co-operate with said further guard means.

6. A workpiece transfer system as claimed in Claim 4 or Claim 5 wherein said guard means is provided with flexible members at the edges adapted to co-operate with said further guard means.

7. A workpiece transfer system as claimed in any one of the preceding claims wherein said rotational axis passes through said guard means, said guard means extending radially from said rotational axis at least in one direction by a 'distance substantially the same as the distance of the radially outermost part of the workpiece support from said rotational axis.

8. A workpiece transfer system as claimed in any one of the preceding claims wherein said workpiece supports are mounted in a manner adapted for movement relative to said rotational axis.

9. A workpiece transfer system as claimed in Claim 8 wherein means are provided for moving said workpiece supports relative to said rotational axis.

10. A workpiece transfer system as claimed in Claim 8 or Claim 9 wherein said guard means is arranged in a plane which also contains the rotational axis, which plane lies at an angle relative to the axis along which said supports may be moved during their movement towards and away from the rotational axis.

11. A workpiece transfer system as claimed in any one of the preceding claims wherein said workpiece supports comprise pallets each adapted to support a workpiece.

12. A workpiece transfer system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. A workpiece transfer system having any novel feature or combination of features, hereinbefore described and/or shown in the accompanying drawings.