TECHNICALFIELD

The invention relates to a transfer device for two-way transfer of a workpiece through an aperture in a screen between an operator side and a robot side of a machine group.

BACKGROUND

Robot-assisted machine groups or machine cells for production of machine parts, e.g. engine components and gearbox components for vehicles, are usually enclosed to prevent persons from entering the robot's working area. When a workpiece needs to be made accessible to an operator between various work operations in a machine group, the robot places the workpiece on a transfer device so that it can be moved to the operator side for manual handling, e.g. for check measurement by the operator, and thereafter be returned to the robot side. A known transfer device of this kind comprises a box intended to contain the workpiece and capable of being moved to and fro through the aperture. Another known transfer device comprises a pair of inclined roller tracks, one of them for running the workpiece out, the other for running the workpiece in. A disadvantage of these known transfer devices is the difficulty of returning workpieces to a precisely defined reception position on the robot side so that the robot can each time, with the aid of predetermined positional data, take back without problems workpieces of varying shapes and sizes. These known transfer devices also occupy a relatively large amount of space and cannot deal satisfactorily with cutting fluids and the like which run off from workpieces.

SUMMARY OF THE INVENTION

An object of the invention is to provide a device of the kind indicated in the introduction which occupies little space and can easily be configured to locate workpieces of varying shape and size accurately each time.

This is achieved by the features indicated in the claims set out below.

According to one version of the invention, the device has on the operator side a raisable shutter which in a lowered position presents a support surface with a retainer for the workpiece on the operator side and in a raised position closes the aperture and presents the support surface with the retainer and the workpiece on the robot side. The device will therefore be very compact while at the same time being capable during normal operation of keeping the aperture fully closed to protect the operator side from the robot.

In the raised position of the raisable shutter, the support surface constitutes with advantage a sloping plane for the workpiece. This makes it possible for the workpiece to slide down to the fixed retainer and be each time in a well-defined position for the robot, particularly if the retainer is of a locating type, a so-called V-block.

The device may also have on the robot side a further shutter which in an angled situation is firmly connected to the raisable shutter in order to close the aperture on the robot side when the raisable shutter is in the lowered position. In this position the further shutter constitutes a protective shield for the operator from the robot.

The further shutter may also be firmly connected to the raisable shutter by a pair of mutually opposite sidewalls which together with the shutters delineate a trough which may have in its bottom an aperture for leading fluid from the workpiece away to a gathering vessel. The sidewalls also serve as a further protection against ingress of the robot into the transfer device when the latter is in an intermediate position.

Other features and advantages of the invention are indicated by the following detailed description and by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view obliquely from the side, with cutaway portions, of a transfer device according to the invention;

FIG. 2 A depicts an operator side of the transfer device in a position in which a workpiece is presented to an operator;

FIG. 2B depicts an operator side of the transfer device in a position in which the workpiece is presented to a robot;

FIG. 3 A depicts a robot side of the transfer device in the position according to FIG. 2B; and

FIG. 3B depicts the robot side of the transfer device in the position according to FIG. 2A.

DETAILED DESCRIPTION OF AN EMBODIMENT EXAMPLE

In FIG. 1, ref. 10 denotes generally a transfer device according to the invention. The transfer device 10 is fitted in an aperture 32 of a screen 30. The screen 30 is part of an enclosure for an undepicted machine group which is assisted by a likewise undepicted handling device which may vary in type but which, to facilitate the description, is here called "robot". The screen 30 may typically comprise a glass portion or a grilled wall.

On the outside, the operator side 36, of the screen 30, the transfer device 10 has a raisable shutter 12 supported for pivoting by means of a bearing arrangement 24 at the

lower edge of the aperture 32. The raisable shutter 12 can be pivoted between a lowered position (FIGS. 2A, 3B) and a raised position (FIGS. 2B, 3A). The raisable shutter 12 has a support surface 14 for a workpiece 50 which is to be transferred by the device 10. On the support surface there is a retainer 20 for the workpiece 50. The retainer 20 comprises in the example depicted an external retainer in the form of a so- called V-block comprising two symmetrical angle supports 22 capable of locating rotationally symmetrical workpieces. The retainer 20 is with advantage connected detachably to the raisable shutter to enable it to be replaced by other types of retainer, e.g. an undepicted V-block for shafts. The retainer may also be an undepicted internally locating retainer in the form of, for example, a pin, cylinder, spherical surface or the like.

In the lowered position of the shutter 12, the operator position, according to FIG. 2 A the support surface 14 is substantially horizontal in order to present the workpiece 50 to an undepicted operator who may optionally carry out desired operations, e.g. checking, measuring or cleaning the workpiece 50 in situ or lifting the workpiece 50 across to an adjacent undepicted workstation. After completion of the operations concerned, the operator puts the workpiece 50 back on the support surface 14 and raises the shutter 12 to the position according to FIG. 2B, the robot position, so that the upper edge of the shutter 12 abuts against the upper portion of the outside 34 of the aperture 32. The shutter 12 may have an undepicted handle on its outside for raising and lowering by the operator. The shutter 12 may be locked in the raised position by a locking mechanism 42 which can be acted upon manually via an operating handle 43. The locking mechanism 42 may also be, for example, electromechanical and the raising of the shutter 12 may also be effected by an undepicted actuator. In addition, the movement of the shutter 12 may be damped, e.g. by an undepicted damping cylinder, to prevent risk of the workpiece 50 falling out of the retainer 20 as a result of rapid retardation.

The raising of the shutter 12 to the robot position according to FIG. 2B and FIG. 3A is detected by a sensor 46 (FIG. 1) when one of a pair of mutually opposite sidewalls 18 of the transfer device 10 reaches a position in front of the sensor 46. A further sensor

48, e.g. an optical sensor, detects via an aperture 49 in the sidewall 18 whether there is or is not a workpiece 50 in the retainer 20. Another sensor, not depicted, detects whether the locking mechanism 42 is in a position which physically locks the shutter 12 in the raised robot position. Only when such is the case is the robot allowed to approach the transfer device in order to take the workpiece. Signals from the sensors are processed in an undepicted computer or the robot's undepicted control system, which may or may not give the robot the go-ahead to take the workpiece 50 for further processing in the machine group.

On the robot side 40 (FIG. 3A) a workpiece 50 will at this stage be presented in the retainer 20 on the support surface 14, which constitutes a sloping plane as a result of the outside 34 of the aperture 32 which faces the operator side 36 (FIG. 1) being angled upwards and outwards. If the operator has not already placed the workpiece 50 in the correct position in the retainer 20, the force of gravity will cause it to slide down along the sloping plane in the V-block of the retainer 20 to the correct position. When the robot has taken the workpiece 50, the shutter 12 may remain in the raised position (robot position) until the next time the operator needs to take a workpiece from the machine group. The transfer device 10 thus occupies a minimum amount of space and need in the depth direction be no thicker than the distance between the mutually opposite sides 34, 38 of the aperture 32.

The robot's next movement of a workpiece from the machine group to the transfer device 10 may be entirely controlled by said computer or partly by the operator, by the operator using a set of buttons 44 to instruct the machine group and the robot to take a workpiece from any desired machine in the group. The robot's return of the workpiece from the transfer device 10 to a machine in the group may also optionally be controlled via the set of buttons 44.

In the embodiment schematically depicted in the drawing, the transfer device 10 also has a further shutter 16 on the robot side 40. The further shutter 16 is firmly connected by the abovementioned sidewalls 18, 18 to the raisable shutter 12 in an angled situation in order to form a trough together with the raisable shutter 12 and the

sidewalls 18, 18. The trough gathers cutting fluids and the like from the workpiece 50 and leads these fluids away through one or more bottom apertures 25 (only one is depicted) and further, e.g. via a hose 26, to a gathering container 28. The fluid may nevertheless also run off in an undepicted manner, directly downwards into an underlying intermediate gathering trough in order to be led away therefrom via a pipeline to a central gathering vessel.

Like the shutter 12, the further shutter 16 also serves to close the aperture 32 and thereby constitutes a protective screen between the operator and the robot when its upper edge region abuts against the upper portion of the inside 38 of the aperture 32. The sidewalls 18, 18 also provide protection against the robot's ingress into the transfer device 10 in the latter's intermediate positions, e.g. that depicted in FIG. 1.