GB2131390A - Automatic handling implement for industrial operations - Google Patents

Abstract

An automatic handling implement for industrial operations, such as machining, comprises a housing (20) rotatable about an axis (17), a plurality of arms (21, 22) spaced around the axis, drive means for imparting an angular movement to the arms, and operating means disposed adjacent the axis of rotation (17) to control tool heads (25, 26) disposed at the ends of the arms (21, 22). As shown each arm (21, 22) has a fixed length, i.e. the toolheads (25, 26) carried by the arms are spaced a fixed distance from the axis of rotation (17). Drive motors for moving the toolheads (25, 26) and tools (29, 30) in at least two degrees of freedom are carried by the arms or by the means for mounting the arms. <IMAGE>

Description

SPECIFICATION Automatic handling implement for industrial operations This invention relates to an automatic handling implement for industrial operations of the type comprising a base, a carrier mounted on the base for rotation about an axis, a plurality of arms angularly spaced about said axis, drive means for imparting an angular movement to the arms, and actuating means disposed adjacent said axis and serving to control tool heads provided at the ends of the arms.

In such a handling implement known from German Patent Specification No. 2,002,987, at least one arm is mounted on a vertical axle disposed in a rotatable bearing arrangement in a rotating housing and is slidable in the longitudinal direction of the arm and carries at each of its outwardly extending ends a gripping device. Two arm sections or arms are aligned with each other or have an angular spacing of 900. Because the arms are longitudinally slidable, the arrangement is unbalanced as regards weight and centre of gravity so that precision machining operations cannot be performed with such an implement.

The known implement serves to rearrange workpieces or to transfer workpieces from one location to another, i.e. to pick up and deposit a workpiece. To pick up a workpiece, a feed movement is required so that the workpiece can be gripped. In that operation the other arm must not be moved into the range of another working device if the arms are aligned. This requirement restricts the field of application of the known implement. In that implement, the feed movement of the arm in one direction or the other is controlled by cams which cooperate with an actuating wedge element in order to initiate the operation of the gripping device. Separate drive motors consisting of piston and cylinder units may alternatively be used for this purpose but their operation is also initiated by means of cams.The arms are guided in the central carrier during their reciprocation; difficulties will arise in that case if the arms are spaced 900 apart.

The known design cannot be embodied in a handling implement used quickly to move various tools to their operating positions for various operations if such tools are mounted in different toolheads and have to be moved to their operating positions by a pivotal movement of the arms.

German Patent Specification No. 2,908,523 discloses an automatic handling implement comprising only one arm which protrudes from the axis of rotation. This arrangement has the disadvantage that the implement cannot be utilised in a favourable manner because work can be performed only towards one side on which the pivoted arm protrudes and the toolhead is disposed.

It is also known to provide in the arm a hollow shaft, which is adapted to be driven, a hollow intermediate shaft and an inner shaft as well as separate motors for driving respective ones of the shafts so that the handling implement can be operated with several degrees of freedom.

In this known implement, the arm is mounted on the carrier for rotation about a horizontal axis and bearings between the carrier and the arm are centred on the axis. If the carrier is mounted on a displaceable and/or rotatable baseplate, the known implement must be so designed and provided with such a bearing arrangement that the arm is disposed over the vertical axis of rotation of the base plate. This concept may be adopted within the scope of the present invention.

It is known to use such handling implements for performing various kinds of industrial operations under the control of a freely programmable electronic control system. Whereas such machines are desirable, they cannot operate precisely unless they have a stable structure particularly for providing a weight balance, and each of them can be associated with only one work station. There will be a loss of production time when the tool carried by the toolhead is to be replaced by a new or different tool.

It is an object of the invention to provide an automatic handling implement which is of the kind described and which differs from the known implements having a plurality of arms and toolheads in that it can be used for a precise and uniform performance of work at different stations and in that it can be serivced without need for rendering the entire implement inoperative. As a result, more tools can be operated, even simultaneously, within a shorter time, and a tool change can be effected more economically than before.

This object is accomplished in accordance with the present invention in that the arm has a fixed length, and motors for driving the toolhead and tools with at least two degrees of freedom are accommodated in the arm and in the bearing arrangement for the arm and can be used to drive shafts which extend one within the other and are rotatable relative to each other. This concept may be adopted in an embodiment which can be used for handling operations and has retractable arms employed only on one side, or in a tool-carrying implement carrying one or more gripped tools, which may be used for faster machining operations. In that arrangement, the servicing and replacement of the tools will also be facilitated.It is essential that the extension with which the arm is provided on the other side will not serve an evading function by an axial displacement of the arm to one side, but that each tool head can be moved to an operating position by a pivotal movement of the arm.

In a preferred arrangement, the arm is axially extended beyond its mounting on the carrier and at least one pivoted double arm is provided. This results in advantages regarding weight balance and a balance of moments because the overhang from the bearing is always the same. These advantages have desirable results particularly as far as the drive is concerned. Within the scope of the present invention, more than two arms, i.e. at least three arms, are preferably associated with the bearing and each of these arms carries a tool head and is associated with separate drive means.

In such an arrangement, more tools can be employed than can be handled by a double arm.

This concept is not adopted for a rearrangement of workpieces or for their transfer from one location to another but permits an improved machining in a shorter time even when tools used for the same operations have been worn and are replaced by new tools or reconditioned in an inoperative position. The use and utilisation of the machine tool can thus be multiplied.

The carrier is preferably pivotally mounted on the base and means are provided for imparting an angular movement to the carrier so as to shift a balanced set of arms or a plurality of arms.

In a preferred embodiment, two degrees of freedom are provided and the arms contain a rotatable inner shaft and a motor for driving that shaft, as well as two rotatably mounted hollow outer shafts which extend in different directions and are connected to a second drive motor, and the hollow outer shafts of the arms extending in different directions are connected by transmitting means. This arrangement is particularly recommendable for embodiments comprising a rotatable arm extending on each side. In that case it will be sufficient to provide two drive motors and associated speed-reducing transmissions.

In another embodiment, three degrees of freedom are provided for the toolhead and in accordance with the invention a hollow intermediate shaft is provided between the inner shaft and each outer hollow shaft and is connected to at least one third drive motor. In an embodiment comprising a rotatable arm extending on each side, this arrangement is desirable regarding the balance and the usability of the tools. In a preferred embodiment a third drive motor is associated with both hollow intermediate shafts and the latter are interconnected by a transmission.

In another desirable embodiment, separate drive motors are provided for ali shafts of each arm, namely the hollow outer shaft, the hollow intermediate shaft and the inner shaft, and clutches are associated with respective ones of the shafts and serve to connect and disconnect each drive motor from the associated shaft which extends to a given tool head.

The embodiments described thus far include a rotatably mounted arm having protruding portions which are aligned with each other. In a particularly preferred embodiment, at least three arms provided with respective tool heads at their free end are rotatably mounted in a single bearing arrangement in the carrier, bevel gear rings are rotatably mounted adjacent the bearing arrangement in mesh with bevel gears mounted on the several shafts and hollow shafts, and a drive motor is associated with each bevel gear ring and has an output shaft carrying a bevel pinion in mesh with the associated bevel gear ring.

The implements in accordance with the present invention which have been described thus far afford important advantages. In order to permit a movement of each tool to an operative position, even under alternative conditions, without the need for a longitudinal displacement or telescopic extension of an arm, the carrier is pivoted on the base and is angularly movable to different positions about the axis of rotation of the arms. As a result, the ends of the several arms, irrespective of whether two or more arms are provided, can be extended and retracted and different working stations can be approached owing to the degrees of freedom provided for the too head.

Automatic handling implements in accordance with the present invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic front elevation showing of an handling implement, Figure 2 is a side elevation of Figure 1, Figure 3 is a top plan view of Figure 1, Figure 4 is an elevation similar to that of Figure 1 and serving to explain the sequence of operations performed by the handling implement, Figure 5 is a side elevation showing the contour and the function of an arm in an embodiment providing two degrees of freedom.

Figure 6 is a view that is similar to that of Figure 5 but showing an arm provided with drive means for three degrees of freedom.

Figure 7 is a view that is similar to that of Figure 6 and illustrating the functions of a substantially separate control of the two toolheads provided at opposite ends of the arm, Figure 8 is a vertical longitudinal sectional view of a toolhead having two degrees of freedom.

Figure 9 is a view similar to that of Figure 8 but showing a toolhead having three degrees of freedom.

Figure 10 is a diagrammatic vertical longitudinal sectional view showing an arrangement with separate drive means for the several shafts of the arm, Figure 11 is a view similar to that of Figure 10 but illustrating a hub with three shafts, Figure 1 2 is a sectional view taken on the line Xll-Xll of Figure 11, Figure 13 is a view that is similar to that of Figure 1 2 but showing a modification, and Figure 14 is a view that is similar to that of Figure 6 but showing another modification.

Figures 1 to 3 illustrate an automatic handling implement comprising a base 1 on which a baseplate 3 is rotatably mounted by means of a circular track 2. A shaft may be provided which is centered on the centre line 4 and connected to a motor for rotating the baseplate 3 on the circular track 2. An upright housing 5 is eccentrically mounted on the baseplate 3 and carries a hollow axle 7 and bearing means 6 for rotatably mounting a carrier 8 on the axle 7. Adjacent the bearing means 6 the carrier 8 is provided with a ring gear 9 which meshes with a pinion 10 on the output shaft of a motor 11 mounted in the housing 5.

A motor 13 mounted in the housing 5 has an ouput shaft which constitutes an inner shaft 1 2 extending into the hollow axle 7. A pulley 14 is carried by the shaft 12 at its inner end and is operatively connected by a transmission, such as a chain drive or a belt drive 15, to a drive pulley 1 6 mounted at the outer end of the carrier 8. The pulley 16 is rotatable about an axis 1 7 on which a bearing extension 18 and a bearing 19 for rotatably mounting an arm 20 are centered. The bearing 19, or another bearing provided in this region, constitutes a separate sub assembly having a separate housing. This design is adopted owing to the magnitude of the periphery of the bearing and the provision of elements extending into adjacent parts.The pulley 1 6 is secured to a shaft centred on the axis 1 7.

In this embodiment, an arm 20 has two portions 21,22 of equal length and extending on opposite sides of the carrier 8. The arm 20 constitutes a housing for transmission and drive means and, if desired, for extensible hollow shafts 23, 24 on which toolheads 25, 26 are respectively mounted.

It is apparent that the midperpendicular of the arm 20 is constituted by the centre line 4 so that a balanced implement is provided. The circular track 2 comprises a ring gear which is in mesh with a pinion 28 on the output shaft of a motor 27.

The handling implement described thus far with reference to Figures 1 to 3 is provided on opposite sides with the toolheads 25, 26 which carry tools 29, 30, respectively, which can be used in succession or in alternation. From this aspect, the pivotal mounting of the carrier 8 is of special significance so that each of the tools 29, 30 can be retracted or extended. The several degrees of freedom will always permit a control to move the selected tool to the correct position for operation.

Reference will now be made to features which are embodied also in the subsequently described embodiments but are not illustrated with reference thereto. Bundles of means 105 and 106 for functional control of the tools 29 and 30 extend from the region of the bearing 1 9 and may consist, for example, of movable shafts or pressure lines for hydraulic or pneumatic fluids. These means may be tied or strapped to the arm 20 along its length so that the operation of the tool is independent of the positioning of the tool.

The abovementioned control means for moving the or each tool 29, 30 to the proper operating position are also apparent from Figure 4 in which the two portions 21, 22 of the arm 20 are shown in a transitional vertical position in which the outer tips of the tools 29, 30 describe a circular path 31 around the axle 17, whereas the carrier 8 is pivoted on the bearing 6 so that the tool 29 would describe the path 32 if the arm 20 were aligned with the carrier, as is shown in Figure 4. The distance between the paths 31 and 32 in the horizontal plane 33 extending through the axis 1 7 indicates that there is a freedom of movement when the arm 20 extends horizontally so that the toolheads 25, 26 can be moved to and from their operating positions in alternation.

In the subsequently described Figures 5 to 7 of the drawings, the contour of the arm 20 is shown as well as the pulley 1 6 for rotating the arm about the axis 1 7, only the central point of which is shown. As before, the arm 20 comprises the portions 21 and 22 which extend in opposite directions. In accordance with Figure 5, hollow shafts 38, 39 are rotatably mounted in the arm portions 21,22 in respective bearings 34, 35 on one side of the axis 1 7 and in respective bearings 36, 37 on the other side of the axis 17, and are provided at their inner ends with respective ring gears 40, 41. These ring gears are in mesh with respective gears 42, 43 connected by a shaft 44 which is rotatably mounted in the arm 20. The ring gear 41 is also in mesh with a pinion 45 secured to the output shaft of a motor 46.By this mechanism the two hollow shafts 38, 39 can be rotated in the direction indicated by the arrow 47.

An inner shaft 48 extends through the two hollow shafts 38, 39 and into the toolheads 25, 26 and in the latter drives a mechanism for driving the tools 29,30 in a second degree of freedom indicated by the arrow 49. A gear 50 mounted on the inner shaft 48 is driven by a pinion 51 secured to the output shaft of a motor 52. This arrangement provides a particularly desirable and selectively variable drive, and a balanced arrangement because the arrangement is symmetrical with respect to the axis 1 7.

Figure 6 shows an embodiment having three degrees of freedom. In addition to the degrees of freedom indicated by the arrows 47 and 49 there is a degree of freedom indicated by an arrow 53.

The hollow outer shafts 38, 39 are driven as before and the inner shaft 48 is surrounded by hollow intermediate shafts 54, 55 which extend into the hollow outer shafts 38, 39 respectively and at their inner ends carry respective ring gears 56, 57 which mesh with gears secured to a backshaft 44. The drive motor 59 has a pinion 60 in mesh with the ring gear 56. In this embodiment, the pinion 51 of the motor 52 is in mesh with a gear 50 on the inner shaft 48. The hollow outer shafts 38, 39 are driven by the drive motor 46 via the elements 40, 42, 43, 44, 55 which constitute transmission means and backshaft.

The embodiment shown in Figure 7 is similar to that of Figure 6 but the two hollow outer shafts 38, 39 are driven by different motors 46 and 61, respectively. Other drive means are the same. The output pinions 45, 62 of the respective motors 46 and 61 mesh with the respective ring gears 41,40 of the hollow outer shafts 38, 39.

In accordance with Figure 7, the hollow intermediate shafts 54, 55 are also driven from separate drive motors 59, 63 through respective transmissions. This permits separate control actions for different purposes.

Figure 8 shows a so called toolhead, such as 26, arranged for two degrees of freedom. The outer hollow shaft 39 is secured to a housing 64 of the toolhead and serves to rotate that housing.

The inner shaft 48 extends into the toolhead 26 and by means of a bevel wheel 65 drives a gear ring 66 secured to a tool carrier 67. This embodiment is surprisingly simple.

Figure 9 shows an illustrative embodiment having three degrees of freedom. The previous description is applicable also to this embodiment; the inner shaft 48 is surrounded by the two hollow shafts 54, 55 each of which, in the manner shown in Figure 8, drives the bevel wheel 65 which, by means of the gear ring 66, imparts a pivotal movement to the tool carrier 67. Another bevel pinion 68 is mounted on the inner shaft 48 of the embodiment of Figure 9 and drives a bevel wheel 70 which is secured to a shaft 69 about which the tool carrier 67 is pivotally movable, and is in mesh with a bevel pinion 71. The latter is non-rotatably secured to a shaft 72 for rotating a tool carrier 73.

A special arrangement is shown in Figures 10 and 11. In accordance with Figure 10, a hub 74 is mounted for rotation about the central axis 1 7.

Different from the previously described arm 20, the hub 74 is a separate component from which four arms 75 to 78 extend in the embodiment shown in Figures 10 and 11. The hub 74 is mounted by means which are similar to the means for mounting the member 20 in Figure 2. To facilitate an understanding of this embodiment, only the inner shafts (designated 48 in Figure 6) are shown in Figure 10 and are designated by the reference numerals 79, 80, 81 and 82. The inner shafts carry respective pinions 83 to 86 which mesh with a bevel gear ring 87 driven by a bevel wheel 88 provided on a motor 89 mounted in the hub 74.

Figure 10 is a schematic representation. In accordance with Figure 11 , the gear ring 87 has associated with it a gear ring 90 for intermediate shafts 91, 92, 93 and 94, and another, outer gear ring 95 for hollow outer shafts 96, 97, 98 and 99.

These gear rings are offset at right angles to the plane of Figure 11 in accordance with the different diameters of the inner, intermediate and outer shafts and have associated with them the drive motor 89 and drive motors 100 and 101, respectively, which are disposed within the hub 74. The hub 74 accommodates also the bearings for the various shafts; these bearings are not shown in Figures 10 and 11. The connection of the shafts to a toolhead is apparent from Figure 9.

Figure 12 ia a diagrammatic sectional view on line Xll-Xll of Figure 11. The inner shaft 80, the hollow intermediate shaft 94 and the hollow outer shaft 99 are apparent, each of which carries the previously described bevel gear ring so that pinions 102, 103 and 104 may be provided on motors which are externally disposed in different planes and may be connected, for example, to respective angled gear trains.

Figure 6 shows separate drive motors and backshafts 44 and 58. In accordance with Figure 14, each of the backshafts 58 and 44 and the inner shaft 48 consist of two sections adapted to be connected and disconnected by clutches 107, 108, 109, respectively. For this reason, motors 110, 111 and 112 are provided in addition to the motors described with reference to Figure 6 and serve to drive the various shaft sections associated with the different arms also when the clutches are disengaged. When a given clutch is engaged, it will be sufficient to operate only one of the motors associated with the respective shaft.

This is suitable for numerous purposes so that in such a case it is sufficient to provide only one motor of each pair, as is shown in Figure 6. This remark applies particularly to embodiments having only two arms. By means of the clutch, one arm may be disconnected from the drive means so that work can be performed on the tool.

In the embodiment shown in Figure 7, the inner shaft 48 may also consist of two sections; in that case a drive motor will be associated with each shaft section.

In Figure 12, the gear rings 87, 90, 95 are shown secured to concentric shafts. The innermost gear ring 87 is secured to a shaft 113 on which a hollow shaft 11 5 is rotatably mounted by bearing means 114. On the hollow shaft 11 5, a hollow shaft 11 7 is rotatably mounted by bearing means 11 6. The gear rings 90 and 95 are secured to the respective hollow shafts 11 5 and 1 7.The bearing means 116 may be mounted in a partition or in a side wall of the beariing means, as is apparent from Figure 13, in which like parts are designated with like reference characters and are accommodated in a bearing 1 9 which has a side wall or partition 11 8 in which the hollow shaft 11 7 is rotatably mounted in a bearing 11 9. Gears 120, 121 and 122 are respectively secured to the hollow shafts 117 and 115 and to the inner shaft 11 3 and are in mesh with respective pinions 123, 124 and 125 of motor units 126,127,128 accommodated in the housing constituted by the arm 20.

In connection with Figure 14 it is pointed out that each of the hollow intermediate shafts 54, 55 contains a bearing 129 or 130 for the inner shaft 48, and each of the hollow shafts 38, 39 contains a bearing 131 or 1 32 for the hollow intermediate shaft 54 or 55. These bearings are only symbolically indicated. In these embodiments, functional lines for operating the tools are also provided on the outside.

Claims (12)

1. An automatic handling implement for industrial operations comprising a base, a carrier mounted on the base for rotation about an axis, a plurality of arms angularly spaced about said axis, drive means for imparting an angular movement to the arms, and actuating means disposed adjacent said axis and serving to control toolheads provided at the ends of the arms, wherein each arm is of a fixed length, and motors for driving the tool head and tools with at least two degrees of freedom are accommodated in the arms and in a bearing arrangement for the arms and can be used to drive relatively rotatable shafts which extend one within another.

2. An implement according to claim 1, wherein two oppositely-directed arms are provided.

3. An implement according to claim 1, wherein at least three arms are associated with the bearing and each arm carries a tool head and is associated with separate drive means.

4. An implement according to any of claims 1 to 3, wherein the carrier is pivotally mounted on the base and means are provided for imparting an angular movement to the carrier so as to shift a balanced set of arms.

5. An implement according to any of claims 1 to 4, two degrees of freedom are provided and the arms contain respective rotatably mounted inner shafts and a motor for driving the inner shafts, as well as respective rotatably mounted hollow outer shafts connected to a second drive motor, the hollow outer shafts being interconnected by drive transmission means.

6. An implement according to claim 5, wherein the drivable inner shafts each consists of a plurality of sections, and a separate drive motor is provided for each section of the inner shafts.

7. An implement according to any of claims 1 to 6, wherein three degrees of freedom are provided for the toolhead, and wherein a hollow intermediate shaft is provided between the inner shaft and each outer hollow shaft, and at least one third motor is provided for driving the intermediate shaft.

8. An implement according to claim 7, wherein a common drive motor is associated with the hollow intermediate shafts, which are interconnected.

9. An implement according to claim 7 or 8, wherein separate drive motors are provided for each shaft of each arm, namely the hollow outer shaft, the hollow intermediate shaft and the inner shafts of each arm, and clutch means are provided for connecting or disconnecting the shafts leading to different toolheads.

10. An implement according to any of claims 1 to 9, wherein at least three arms provided with respective toolheads at their free ends are rotatably mounted in a single bearing arrangement in the carrier, bevel ring gears are rotatably mounted adjacent the bearing arrangement and mesh with bevel gears mounted on the several shafts and hollow shafts, and a drive motor is associated with each bevel ring gear and has an output shaft carrying a bevel pinion in mesh with the associated bevel ring gear.

11. An implement according to claim 10, wherein the bevel gear rings are concentrically mounted in a wall portion.

12. An implement substantially as hereinbefore described with reference to Figures 1 to 4, or Figure 5, or Figure 6, or Figure 7, or Figure 8, or Figure 9, or Figure 10, or Figures 11 and 12, or Figure 1 3 or Figure 14 of the accompanying drawings.