GB2149696A

GB2149696A - Tool pot for an automatic tool changer

Info

Publication number: GB2149696A
Application number: GB08428357A
Authority: GB
Inventors: Kazutomi Ishikawa
Original assignee: MORI MACHINERY; MORI MACHINERY CO Ltd
Current assignee: MORI MACHINERY; MORI MACHINERY CO Ltd
Priority date: 1983-11-09
Filing date: 1984-11-09
Publication date: 1985-06-19
Also published as: IT8423499A1; DE3440357A1; IT1177135B; GB2149696B; IT8423499A0; DE8432355U1; GB8428357D0

Abstract

A tool pot (15) for an automatic tool changer for a machining centre includes a cylindrical metal body (16) serving as the tool pot and a separate removable clamp housing (20). The clamp housing (20) is retained in the body by a retaining ring (25) and has a boss hole (21) for receiving a tool holder boss (7), that is located at the bottom portion of the cylindrical metal body (16). In addition, to the boss hole (21) the clamp housing (20) may include a mechanical lock for locking the tool holder. The clamp housing (20) is constructed as an independent single unit, and is freely attachable to and detachable from the cylindrical metal body (16). The cylindrical body (16) is provided with a ring (40) made of a material softer than the metal of the body (16). <IMAGE>

Description

SPECIFICATION Tool pot for an automatic tool changer This invention relates to a tool pot for an automatic tool changer for a machining centre, and particularly to a tool pot for an automatic tool changer system.

A tool pot of an automatic tool changer (hereinafter abbreviated at ATC) for machining centre is a component used in large numbers as a part of a chain pin or by being disposed on a drum, disk, or rack. Such a tool pot constitutes a main component part of an ATC.

Figure 4 shows an example of a conventional tool pot set up in a tool pot chain. What is shown in Figure 4 is a tool pot chain composed of cylindrical pins 4 forming tool pots 3 which are located alternately in series by two pairs of (upper and lower) track form link plates 1 and 2. The cylindrical pin 4 is formed at its upper end with a tapered edge portion 6 having a tapered surface that matches the taper of a tool holder 5, and formed at its lower end into a pot shape having, at its centre, a hole 8 for receiving a tool holder boss 7. Horizontal holes 11 each housing a boss support ball 9 and a backing spring 10 for the boss support ball 9 are provided at the lower end of the cylindrical pin 4.These horizontal holes 11 are disposed, for example, at three places around the boss hole 8, in the direction of the outer circumference of the cylindrical pin, with an angle of 120 degrees between each horizontal hole 11.

In addition to the conventional tool pot mentioned above, there are types of tool pots presently available. For example, there are tool pots having a double structure wherein, in order to reduce the weight of the tool pot and also to protect the tapered portion thereof, the metal ring wall of the cylindrical pin 4 is reduced in thickness and a tapered pot made of resin is inserted into the cylindrical pin 4. There are also proposed tool pots with a structure wherein a lock point is inserted vertically into the horizontal hole 11 in order to keep the support ball 9 from retracting easily.

The conventional type of tool pot shown in Figure 4 has the following disadvantages. In this type of tool pot, the cylindrical pin 4 and the bottom portion provided with the boss hole 8 are made as a single unit. Accordingly, as well as requiring a lot of labour for manufacturing the unit, when the boss hole 8 wears the entire body of the tool pot including the cylindrical pin 4 has to be changed.

Also, because the inner surface of the tool pot is formed only by the metal cylindrical pin 4, the tapered outer surface of the tool holder is scratched and damaged. However, when the tool pot is made of resin to protect the hool holder from getting damaged, the manufacturing cost is increased, and the durability of the resin tool pot is lower than that of a metal tool pot. Thus, satisfactory results are not always obtainable by such modifications.

The present invention, therefore, is intended to minimise the foregoing problems suffered by conventional tool pots.

According to the present invention there is provided a tool pot for an automatic tool changer, having a cylindrical metal body in which a tool holder may be removably located, and a separate clamp housing removably attachable to and detachable from the cylindrical metal body, in which clamp housing is provided a boss hole for releasably receiving a boss provided on a lower portion of a tool holder when the latter is located in the cylindrical metal body.

The tool pot provided by this invention is basically made of metal to facilitate its manufacture process as well as its maintenance, preferably with resin used partially to obtain a better product.

By constructing the clamp housing as a separate unit assembly and maintenance of the ATC are improved. In this way, each clamp housing can be mounted onto a tool pot body, chain pin, etc.

freely and can be exchanged separately from the tool pot body, chain pin, etc. thereby making it easier for assembly and maintenance of the ATC.

Preferably a mechanical lock for the tool holder is provided which contributes to an increase in holding weight of the tool holder for the ATC, thus making is possible to hold a large size tool, and also contributes to the elimination of accidental dropping of the tool holder during high speed movement of the carriage. The mechanical lock as a safe and reliable arrester against the tool holder slipping from the tool pot preferably is provided in the clamp housing unit and constructed as follows.

A pin insertion bore including a pin hole and a pin head receiving hole which are disposed in stepped form is formed along the side face of a tool holder boss insertion hole at the bottom portion of the cylindrical metal body that forms the tool pot, and a safety lock pin, having a pin head at the end facing the inner surface of the tool pot and a lock head at the end facing outward is inserted into the pin insertion bore. Preferably this safety lock pin is elastically urged in an outward direction by a spring provided outside the bottom portion of the cylindrical metal body.

In order to provide a tool pot for the ATC, which is light in weight and capable of protecting the tapered surface of the tool holder, a ring with low hardness may be fitted in the upper edge portion of the tool pot. That is, a ring made of material, such as resin or metal, with a hardness lower than that of metal used for the tool holder, is fitted to the surface of the upper edge portion of the cylindrical metal body and comes into contact with the tapered portion of the tool holder. By combining the three foregoing improvements it is possible to provide a tool pot capable of coping sufficiently with operational conditions of the ATC no matter how severe those conditions are, while working as a main component part of the ATC.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a vertical sectional view showing a tool pot according to one embodiment of the pres ent, set up in a tool pot chain for an ATC, Figure 2 is a bottom view of Figure 1, Figure 3 is a vertical sectional view corresponding to that of Figure 1, showing a tool pot according to another embodiment of the present invention; and Figure 4 is a vertical sectional view similar to that of Figure 1, showing a conventional tool pot not according to the invention.

In a tool pot 15 according to the present invention a clamp housing 20 is provided as a separate unit, removably locatable in an aperture in the lower end of a cylindrical metal body 16 of the tool pot 15. The housing 20 has a boss hole 21 opening therethrough at its centre and steel balls 22 for supporting a boss 7 of a tool holder 5, when in the pot 15, with the boss 7 projecting into the hole 21.

The claim housing 20 also includes a lock pin 24 with an enlarged diameter disc shaped pin head 23, which function as a mechanical lock. The parts of the housing 20 are shown in Figures 1 and 2 will be described in more detail later.

Figure 3 shows the clamp housing 20 without the optional mechanical lock. The clamp housing is removably mounted on the cylindrical metal body 16 of the tool pot 15 by a retaining ring 25 fitting in a groove around the inner surface of the body 16 as shown in Figures 1 and 3.

As shown in Figures 1, 2 and 3 the steel support balls 22 are held elastically one in each of three radial bores opening from the boss hole 21, at three spaced locations therearound. Each steel ball 22 is elastically or resiliently urged along the accommodating radial bore, by a coil spring 26 retained in the bore by a presser ring 27, towards the boss hole 2 into which it projects partially in its end most portion as shown in Figures 1 to 3. Thus the steel balls 22 engage a sloping surface A of the tool holder boss 7 in the hole 21 from three directions to retain the holder 5 in the tool pot 15.

The safety lock pin 24 prevents the tool holder 5 from slipping out of the tool pot 15. The pin head 23 faces towards the interior of the tool pot whilst the opposite end of the pin 24 is formed as a lock head 28 projecting or facing outwardly of the housing 20. The lock pin 24 is inserted in a lock pin bore 29 opening at least partially through the housing 20 laterally into the boss hole 21. The lock pin bore 29 has a stepped configuration including at its upper portion an enlarged pin head receiving hole 30 in which the pin head 23 is received and a pin head release hole 31 larger in size than the pin head 23 and hole 30.The safety lock pin 24 is held elastically in the bore 29 by a leaf spring 32 se cured to the bottom surface of the cylindrical body 16 in a manner such that the pin head 23 of the safety lock pin 24 in the bore 29 is normally urged into the pin head receiving hole 30. The leaf spring 32 made from planar material has a shape as shown in Figure 2, and engages behind the lock head 28 continually to urge the lock pin 24 in a downward direction towards the exterior of the housing 20.

In Figure 1, when a tool holder 5 is to be in serted in the tool pot 15, the lock head 28 of the safety lock pin 24 is pressed upwardly in the direction indicated by an arrow, from below against the elastic force of the leaf spring 32 in response to an electric signal, so that the lock pin 24 is brought into the unlocked position indicated by the two-dot chain lines in Figure 1 in which the head 23 is located in the hole 31. In this position the head 23 does not project laterally into the boss hole 21 in engagement with tool holder boss 7, which can therefore be inserted to the position shown in solid lines by riding over and passing by the disc-form pin head 23. In this position, when the unlocking pressing force applied to the safety lock pin 24 is removed, the pin returns to the position indicated by solid lines in Figure 1 under the return force of the leaf spring 32.Consequently, the pin head 23 returns to the pin head receiving hole 30 and the tool holder 5 is locked in the tool pot 15 and is thereby prevented from coming out inadvertantly.

If an attempt is made to remove the tool holder 5 from the tool pot 15 forcibly while the tool holder 5 is in the retained locked position as indicated by the solid lines, the pin head 23 is pressed radially outwardly by the sloping surface A of the tool holder boss 7 to wedge the pin head 23 laterally against the shoulders of the hole 30 preventing side ways and axial movement of the pin head 23 and hence preventing removal of the boss 7 from the boss hole 21.

The shape of the pin head 23 is not limited to a disc-form, but may have the shape of a flat ball or an egg-form or a spherical form so long as it satisfies the requirements that insertion of the boss 7 in the hole 21 is not prevented by it and that the wedging effect can be obtained by it in the locked state. Also in addition or alternative to the leaf spring 32, a coil spring acting between the lock head 28 and a bottom surface of the cylindrical body or of the housing 20 may be used.

To detach the tool holder 5 from the tool pot 15, that is, to remove the boss 7 of the tool holder 5 from the boss hole 21 in the clamp housing 20, the pin 24 is pressed upwardly from below against the return action of the leaf spring 32 to bring the lock pin 24 in to the position indicated by the two-dot chain linesin Figure 1 to free the boss 7 for axial removal from the hole 21.

As a guide for inserting the boss 7 into the boss hole 21, a tapered guide ring 33 is provided at the entrance of the boss hole 21.

A low hardness ring 40 is provided in the upper edge portion of the tool pot 15. The cylindrical body 16 forming the tool pot 15 is made of metal, and in the upper edge portion 41 of the cylindrical metal body is provided a tapered surface 42 that matches the taper of the tool holder 5 to be used.

Into this portion 41, a low hardness ring 40 made of synthetic resin, metal with a hardness lower than that of the metal forming the tool holder, or other suitable material, is inserted.

In the illustrated embodiments the ring 40 is made of synthetic resin. Part of the upper edge portion of the cylindrical body 16 is formed into the tapered surface 42. In the embodiment shown in Figure 1, a fitting groove 43 is formed by di rectly cutting the upper edge portion 41 from the top edge of the cylindrical body 4. In the embodiment shown in Figure 3, a dovetail shaped fitting groove 43 with a dovetail-shaped section into which the ring 40 is inserted independently is formed. The insertion of the ring is carried out for example by pressure insertion of the ring 40 into the fitting groove 43 or by a process wherein a length of a band of material is fitted into the fitting groove 43 and it is cut to a length corresponding to that of the fitting groove and then adhered thereto by adhesive.

Since the ring 40 inserted into the fitting groove 43 of the tapered surface 42 is made of resin, contact between metals can be avoided, thus preventing noise and damage. The material for the low hardness ring 40 is not limited to resin, and metals lower in hardness than the material of the tool pot, such as copper, copper alloy, show a similar effect and are suitable. As the resins suitable for use, those having an appropriate resistance to oil and chemicals are preferable. For example, in addition to nylon and polyurethane, polyester, polyethylene, polypropylene ABS, polyvinyl alcohol, and polyvinyl formal resins may be used. Through the use of low hardness ring 40, the damage to the tool holder which was caused by the conventional tool pot made of metal is eliminated.

The embodiment shown in Figure 3 shows the tool pot chain with the foregoing low hardness ring 40 and a separate clamp housing 20 unit incorporated in the cylindrical body. Because the whole body of the tool pot is made of metal, its outside diameter can be made smaller than that of a tool pot made of resin, even when the taper of the tool holder is the same. As a result, its chain width and chain pitch also become smaller. For example, in the case of a No. 50 taper 7/24 tool holder, the chain width using a tool pot according to the present invention can be reduced from 120mm to 115mm, and the outside diameter of the cylindrical body 15 forming the chain pin can also be reduced from 92 0 to 82 0. Furthermore, the thickness of the wall of the cylindrical body 15 is increased from 6mm to 8.5mm, resulting in higher rigidity with a reduction in size of the product.

Moreover, since the clamp housing 20 is constructed as a separate unit, the boss hole area that is most susceptible to damage can be replaced in its entirety, thereby making it possible to prolong of the life of the tool pot.

The embodiment shown in Figure 3 is obtained by adding the mechanical lock to the clamp housing unit. By this addition, the weight of the tool holder to be held by the tool pot can be increased, and also high speed exchange becomes feasible.

Thus, as a whole, a reduction in size and weight of the ATC system can be realised. In addition, besides the high speed exchange, low cost and ease in maintenance are also brought about this system.

Claims

1. A tool pot for an automatic tool changer, having a cylindrical metal body in which a tool holder may be removably located, and in a separate clamp housing removably attachable to and detachable from the cylindrical metal body, in which clamp housing is provided a boss hole for releasably receiving a boss provided on a lower portion of a tool holder when the latter is located in the cylindrical metal body.

2. A tool pot according to claim 1, wherein the clamp housing is removably attachable in and removable from the cylindrical metal body by means of a retaining ring removably locatable on an inner surface of the cylindrical body near the bottom thereof.

3. A tool pot according to claim 1 or claim 2, including a pin insertion bore opening at least partially through the clamp housing laterally into the boss hole, which bore has a stepped configuration including a pin head receiving hole and a pin head release hole which are dimensioned to provide the stepped configuration, a safety lock pin insertable in the pin insertion bore so that a pin head at one end of the safety lock pin faces towards the inner surface of the tool pot when the housing is attached to the body and a lock head at the opposite end of the pin faces outwardly of the housing, and a spring disposed outside of or adjacent to the bottom surface of the housing for elastically urging the safety lock pin outwardly of the housing.

4. A tool pot for an automatic tool changer according to claim 3, wherein the pin head of the safety lock pin is disc shaped.

5. A tool pot for an automatic tool changer, according to claim 3, wherein the pin head of the safety lock pin has a ball like form.

6. A tool pot for an automatic tool changer according to any one of claims 1 to 5, wherein a ring made of material with a hardness lower than that of the metal forming the tool holder to be used is fitted into an upper edge portion of the cylindrical metal body.

7. A tool pot for an automatic tool changer according to claim 6, wherein the ring is fitted into the upper edge portion of the cylindrical metal body by pressure insertion of the ring.

8. A tool pot for an automatic tool changer according to claim 6, wherein the ring is fitted into the upper edge portion of the cylindrical metal body by inserting a piece of a length of a band of material into a ring fitting groove formed in the upper edge portion of the cylindrical metal body.

9. A tool pot for an automatic tool changer according to claim 6, wherein the ring is made of synthetic resin ring matching the tapered surface of the tool holder to be used.

10. A tool pot for an automatic tool changer according to claim 9, wherein the synthetic resin ring has a tapered surface matching the taper of the tool holder to be used.

11. A tool pot for an automatic tool changer substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 of the accompanying drawings.