GB2025807A

GB2025807A - A Transfer Mechanism for Moving a Body Between Two Locations

Info

Publication number: GB2025807A
Application number: GB7925018A
Authority: GB
Original assignee: HERBERT Ltd A
Current assignee: HERBERT Ltd A
Priority date: 1978-07-27
Filing date: 1979-07-18
Publication date: 1980-01-30

Abstract

In a machine tool there is provided a tool transfer mechanism for moving a body such as a tool holder 20 between two locations such as a working station 14 and a tool storage device 17. The transfer mechanism includes a transfer arm 21 and a support arm 22 both pivotally connected to a transfer member 200 which incorporates releasable locking means 44 for locking the tool holder 20 onto it for transfer purposes. Drive means including a ram 48 and a rack 46 move the transfer arm angularly and thus, via gearing, moves the transfer member between the two locations in either direction to effect a transfer movement. <IMAGE>

Description

SPECIFICATION A Transfer Mechanism for Moving a Body Between Two Locations This invention relates to a transfer mechanism for moving a body between two locations and is particularly applicable to the transfer of a tool holder between a tool storage magazine and a machining station in a machine tool. The invention also embraces a machine tool incorporating the aforesaid transfer mechanism.

According to the invention, a transfer mechanism for moving a body between two locations comprises a transfer member having locking means operable to permit the member to be releasably attached to the body, the transfer member being connected to drive means arranged and operable to move the transfer member between positions in which the locking means is directed towards the body when the latter is disposed respectively in said locations, whereby the transfer member may be locked to the body at either location, the assembly of body and transfer member moved by the drive means to the other location, and the transfer member then released from the body.

In one convenient arrangement, the transfer member is pivotally connected to a transfer arm swingable by the drive means to move the transfer member between said positions, and is pivotally connected also to a support arm which is swingable to permit said swinging of the transfer member by the transfer arm whilst providing support therefore. The transfer member is preferably carried solely by the transfer and support arms.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figures 1 and 2 are respectively a front elevation and plan view of one form of machine tool of the invention; Figure 3 is a partly sectioned plan view of the machine tool of Figures 1 and 2, illustrating a tool transfer mechanism in greater detail in one of its operative positions; Figure 4 is a view generally similar to Figure 3 showing part of the transfer mechanism in another operative condition; Figure 5 is a view from underneath of part of the mechanism shown in Figure 3; Figure 5A is a section along line B-B of Figure 5 and Figure 5B is a detail of the transfer mechanism; Figure 6 is a cross-section along the line A-A of Figure 5, and Figure 7 is a vertical cross-section of part of the machine tool of Figures 1 and 2.

Referring to Figures 1 and 2 of the drawings, these show a turning machine having a base 1 to which are secured two vertical columns 2 and 3 carrying respective slideways 4 and 5. Mounted on the slideways respectively for vertical reciprocatory sliding movement are saddles 6 and 7 carrying respective transverse slides 8 and 9.

The slide 8 carries a tool transfer mechanism indicated generally at 10, as well as a tool drive and thrust-applying mechanism, indicated generally at 11, both of which mechanisms 10 and 11 will be described more fully hereafter. The slide 9 has mounted thereon an indexable turret 12 of conventional type, carrying a plurality of tools 1 3. A chuck 14 is arranged for rotation about a vertical axis and is adapted to grip a component, represented at 1 5, in jaws 1 6. A tool storage magazine indicated generally at 1 7 is mounted on the base 1 for rotary indexing movement about a vertical axis and has a number of tool storage positions 1 8 arranged in two tiers, one above the other and each of which would normally carry a stored tool 19 held in a respective tool holder 20.

The transfer mechanism for transferring tool holders from the tool storage magazine 1 7 to the slide 8 is shown in more detail in Figures 3 to 6.

This mechanism comprises a transfer plate 200 supported on the slide 8 by way of a transfer lever 21 and a support lever 22. As will be seen more clearly from Figure 6, the transfer lever 21 is fast for rotation with a shaft 23 rotatably supported in the slide 8 by way of bearings 24. A gear quadrant 25 is centred on the shaft 23 and prevented from rotating about the shaft by engagement therewith of a peg 26 secured in the slide. The transfer lever is recessed in a generally central region thereof to receive an idler gear 27 mounted on a shaft 28 by way of bearings 29 and meshing with both the gear quadrant 25, so as to be driven thereby, and with a gear segment 30 rigidly secured to the transfer plate 200 so as to be capable of driving the latter. The gear segment 30 and transfer plate 200 are mounted on a shaft 31 secured to the transfer lever 21. The transfer plate 200 contains a number of hydraulically operated locking plungers 44 (Figures 5B), for the purpose to be described, and ail for operation of these plungers is supplied to the plate via an inlet A, an axial drilling 32 in the shaft 23, a transfer pipe 32A extending along the transfer lever 21 and an axial drilling 33 in the shaft 31 leading to a supply passage 34 of the transfer plate.

The transfer plate 200 is supported towards its other end by the support lever 22 which is mounted on the base 1 for pivotal movement about an axis 35. The transfer plate is pivotally mounted on a shaft 36 (Figure 5A) running in a bearing 37 housed within the transfer plate. The shaft 36 is an extension of a block 38 secured beneath the transfer plate and forming a socket 39 within which is slidably received a shank 40 of the support lever 22. The shaft 36 and shaft 40 are provided with fluid tight seals against the surfaces with which they engage and a supply passage 41 of the transfer plate communicates with a passage 42 extending through the shaft 36 and support lever 22, the passage 42 being connected to a fluid connection 43. This arrangement is again concerned with the flow of oil required for operation of the aforesaid locking plungers.

The function of the transfer plate is to form a releasabie connection with a tool holder 20 stored in the storage magazine 1 7 and to support the tool holder during transfer thereof to the tool drive and thrust-applying mechanism 11. For this purpose, the transfer plate is provided with a system of fluid pressure-operated mutually angled plungers 44, as illustrated in Figure SE, and as described in more detail in our co-pending Application No. entitled "Means for Paleasably Securing Together a Pair of Members". Briefly, the plungers are provided in groups, usually pairs at sach location where a securing function is required, the plungers 44 of each pair being disposed at an angle to the irKerface 45 between the tool holder and the surface ef the transfer plate to which it is secured, and at an angle to each other. Each plunger is connected to a piston 48 slidable in a cylinder 47 formed in the transfer plate, under the action of hydraulic pressure supplied to the cylinder through supply passages 34 and 41 and other passages within the transfer plate, some of which are indicated at 48. Bores 49 are formed in the tool holder and arranged so as closely to receive a respective one of the plungers 44. Desirably, the bores contain spring-loaded dummy plungers (not shown) which normally fill the bores to preclude ingress of foreign material, but which are displaced by the plungers 44 when the securing function is required.

In order to change a tool already in position on the slide 8 for another contained in the storage magazine, the transfer plate is required to swing through 90 so that its face indicated at B, to which the tool holder 20 is secured for transfer purposes, is moved from position C when the holder is located in the magazine, to position D, when the holder is located on the slide 8.

Swinging of the transfer plate between these two positions is effected by means of the transfer lever 21 which is driven from the shaft 23. For this purpose and as seen more clearly from Figure 3, the shaft 23 has a gear 45 fast for rotation therewith and meshing with a rack 46 connected to the piston rod 47 of a ram 48, the rack engaging and being supported by a roller 49. The rack is shown in two extreme positions of movement, the starting position being that shown in broken lines in which the rack is disposed away from the ram. As the piston rod and the attached rack are retracted towards the ram, the shaft 23 is rotated in a direction such as to swing the arm 21 in an anti-clockwise direction as seen in Figure 5.

Since the gear quadrant 26 is held stationary by the peg 26, movement of the arm 21 as aforesaid causes the idler gear 29 to roll around the gear quadrant and so rotate in an anti-clockwise direction. This rotation of the idler causes the gear segment 30 and thus the end portion of the transfer plate to which it is attached to move angularly in 3 clockwise direction. Simultaneously with this, the longitudinal axis of the shaft 36 carrying the opposite end portion of the transfer plate begins to swing along &commat; a path indicated by the curve E, causing the lever 22 to pivot in an anti-clockwise direction about the pivotal axis 35.

As the ievers perform their respective angular movements, the distance of the shaft 36 from the pivotal axis 35 varies and this is accommodated by the shank 40 of the support lever sliding within the socket 39 so as effectively to vary the iength of the support lever 22. The arrangement of the rack and gears is such that the transfer plate 20 is pivoted through 900 to the position shown in broken lines in Figure 5 and transfer plate is effectively supported by the levers 29 and 22 during the whole of the aforesaid movement.

One face of each tool holder 20 is formed as or has secured thereto one part 51 of e:toothed coupling, indicated generally at 50 (Figure 7), the other part 52 of which is secured to the slide 8.

Trapped behind the toothed coupling portion 51 is a locking sleeve 53 dimensioned to pass through a central opening in the toothed coupling portion 52. A locking mechanism for the tool holder is disposed on the slide and consists of an inner sleeve 54 having circumferentially arranged apertures towards one end thereof, each of which contains a locking ball 55. The bore of the sleeve 54 is stepped and the sleeve receives therein a lock actuating member indicated generally at 56, which is correspondingly stepped to form a piston 57 slidable within the larger portion of the sleeve and a plunger 58 slidable within the smaller portion of the sleeve, the forward end of the plunger having a conical surface 59 tapering towards the free end of the plunger. The balls 55 engage the wedge surface end more radially inwardly and outwardly under the influence thereof.

The lock actuating member 58 is normally withdrawn to the right as seen in Figure 7, permitting the balls 55 to move inwardly of the sleeve 54 so that the sleeve 53 may pass over the balls as the tool holder 20 is brought towards theS slide, thus permitting engagement of the tooth coupling 50. When the tooth coupling has been engaged, the piston 57 is actuated by fluid pressure to move the plunger 58 to the left so that the conical surface 59 urges the balls 55 radially outwardly into contact with inclined internal surfaces 60 of the sleeve 53, thereby creating a large wedging force urging the tooth coupling portions 51 and 52 into tight engagement. With the tooth coupling so engaged, the tool holder 20 is in its operative position in which a working operation can be performed by a tool, such as a drill or boring bar 61 held in the tool holder.

The tool drive and thrust-applying mechanism 11 is disposed invaxlsl alignment with the operative position of the tool holder and includes a hydraulic ram 62 for applying a relatively light thrust to the tool 61, or other device such as a live centre mounted in the tool holder. The mechanism 11 may also apply rotary drive to the tool, if desired, from a motor 62A via a toothed coupling 63 which may be engaged and disengaged under the action of the ram 62.

As shown more clearly in Figure 4, each tool station of the tool magazine is provided with retaining means for releasably holding a fespective tool holder in position thereon. Each retaining means indicated generally at 70, comprises a locking sleeve 71 having a circumferentiai row of apertures containing respective balls 72, each of which bears on a conical nose portion 73 of a plunger 74 loaded towards the balls by means of a coil spring 75.

The force of the spring 75 is such that the sleeve 53 of the tool holder can displace the balls inwardly by moving the plunger rearwardly, when the tool holder is offered to the locking mechanism by the transfer plate 200. The force of the spring 75 is also such that the tool holder can be removed from the magazine by a pull exerted through the connected transfer plate 200 to move the holder towards the slide 8. Such a pull again forces the balls 72 inwardly, so displacing the plunger 74 against the spring 75 as before.

When a tool in its operation position is to be replaced by another tool from the tool magazine, the shaft 23 is driven to bring the transfer plate 200 to the position D indicated in Figure 4 in which it engages a face of the tool holder 20.

Plungers 44 in the transfer plate are then actuated to lock the transfer plate on to the tool holder, following which the lock actuating member 56 is operated to withdraw the plunger 58, thereby releasing the balls 55 to unlock the holder from the slide. The transfer plate is now swung through 900 to the position C shown in Figure 4 so that the locking sleeve 53 of the holder is aligned with the retaining means 70 of an empty tool station of the tool magazine, which would normally be the station from which the holder was previously removed. The slide 8 is then moved towards the magazine until the holder 20 carried by the transfer plate 200 arrives at the aforesaid empty station and the sleeve 53 of the holder engages over the retaining means 70 to be locked by the balls 72 upon operation of the plunger 74.

The plungers 44 of the transfer plate are then withdrawn to release the plate from the holder and the slide 8 is then withdrawn sufficiently to permit the latter to index and bring a further tool, either on the same tier or on the other tier, into position for pick-up. The slide 8 is then reversed, preceded by vertical movement of the saddle 7 if the slide is not at the correct level for the tool to be picked up, and the transfer plate engaged with the appropriate tool holder 200. The transfer sequence then takes place in the reverse manner to that described above to bring the selected tool holder into position on the slide for the performance of a subsequent machining operation. The plungers 44 are preferably positively operated both for engagement and withdrawal.

It will be appreciated that the mating faces of the tool holders 20 may be of any desired configuration, such as curved, instead of flat as shown, and any convenient number of plungers of any desired cross-section may be provided at each interface where locking is required. Although the drive and thrust applying means 11 is shown mounted on the slide 8, it would be possible for this to be fixed in alignment with the working station and only the transfer arm 21 to move with the slide 8.

The aforesaid transfer operation would normally be performed under automatic control by the N.C. functions of an automatic machine tool, the necessary position sensing of parts and production of control signals being effected by conventional N.C. control systems.

Claims

1. A transfer mechanism for moving a body between two locations comprises a transfer member having locking means operable to permit the member to be releasably attached to the body, the transfer member being connected to drive means arranged and operable to move the transfer member between positions in which the locking means is directed towards the body when the latter is disposed respectively in said locations, whereby the transfer member may be locked to the body at either location, the assembly of body and transfer member moved by the drive means to the other location, and the transfer member then released from the body.

2. A transfer mechanism according to Claim 1 wherein the transfer member is pivotally connected to a transfer arm swingable by the drive means to move the transfer member between said positions, and is pivotally connected also to a support arm which is swingable to permit said swinging of the transfer member by the transfer arm whilst providing support therefore.

3. A transfer mechanism according to Claim 2 wherein the transfer member is preferably carried solely by the transfer and support arms.

4. A transfer mechanism according to Claim 2 or Claim 3 wherein the support arm is arranged so that its length can vary during its swinging movement.

5. A transfer mechanism according to any one of Claims 2 to 4 wherein the drive means includes a ram drivingly connected to a shaft with which the transfer arm is fast for rotation, the transfer arm carrying an idler gear meshing with a fixed toothed formation and with further toothed formation on member coupled to the transfer member, whereby angular movement of the transfer arm causes the idler gear to rotate around said fixed tooth formation and impart angular drive to the transfer member via said further toothed formation.

6. A transfer mechanism according to Claim 5 wherein the fixed and further toothed formations are gear segments.

7. A transfer mechanism according to Claim 4 or Claim 5 wherein the ram is connected to a rack meshing with a gear fast for rotation with the shaft carrying the transfer arm.

8. A transfer mechanism according to any one of the preceding claims wherein the locking means comprises plungers in the transfer member engageable with complementary bores in the body, the plungers being at an angle to the surface of the body through which they enter the bores, and to each other.

9. A transfer mechanism substantially as hereinbefore described with reference to the accompanying drawings.

10. A machine tool incorporating a transfer mechanism according to any one of the preceding claims arranged to transfer tools and like devices between a working station and a tool storage device.