Device and method for cooling tool holders comprising shrink fit chucks

Device and method for cooling tool holders comprising shrink fit chucks description/claims

The present invention relates to a device and a method for cooling tool holders with shrink fit chucks.

Tool holders with shrink fit chucks come in all variations. They serve to clamp piping, turning, milling, reaming and grinding tools and the like by a thermally induced shrinking process. Usually, such shrink fit chucks are thermally heated by inductive shrinking devices, as a result of which the inside diameter of the shrink fit chuck is enlarged. With the inside diameter enlarged, a tool to be clamped is inserted into the shrink fit chuck, with the ratio of the inner diameter of the shrink fit chuck to the shaft diameter of the tool designed such that, on subsequent cooling of the shrink fit chuck, the tool is firmly clamped by the shrink fit chuck and cannot rotate.

To accelerate cooling, cooling devices with ring-like heat sinks are often used, with the heat sink having an internal geometry adapted to the shrink fit chuck and being flowed through by a coolant. The disadvantage of these heat sinks is that adapting them to different shrink fit chuck dimensions is very difficult and often thermally ineffective and therefore a plurality of heat sinks must be kept available for the different shrink fit chucks.

For the purpose of avoiding this disadvantage, direct cooling devices are known that usually employ a coolant along with additives to prevent rusting. The shrink fit chuck together with the inserted tool is introduced into a housing, which is then closed water-tight in order that it may be cooled by the coolant. To be sure, the cooling device is highly versatile for use with all kinds of shrink fit chucks, but such a cooling device is unsuitable for cooling several shrink fit chucks in direct succession, especially in an automated process.

An object of the present invention is to provide a device for cooling tool holders with shrink fit chucks, said device being versatile for use with all kinds of tool holders while simultaneously facilitating more efficient cooling of several tool holders, particularly in direct succession.

According to an aspect of the present invention, the device for cooling tool holders with shrink fit chucks, which are accommodated in a tool holder receptacle, comprises means for spraying the tool holder with coolants (e.g., in liquid form), means for transporting the tool holder receptacle, and means for activating the means for cooling and the means for transporting. In this connection, the means for transporting are adapted for simultaneously transporting several tool holder receptacles through the device in succession.

The means for transporting the tool holder receptacles has an advantage of ensuring that not only one tool holder receptacle but several tool holder receptacles can be transported simultaneously in succession through the device and thus it is no longer necessary as it was before to await the cooling process at one tool holder before a further tool holder can be transported to such a cooling device by hand. The inventive cooling device is therefore much more efficient and allows the cooling process for several successive tool holders to be automated.

Advantageously, the means for transporting transports the tool holder receptacle can be substantially horizontal through the device, as that keeps down the design effort.

The means for activation can be adapted such that the device can be operated semi-automatically, and preferably fully automatically. A semi-automatic operation can be made possible, for example, in such a manner that a corresponding push-button for operation by the operating personnel is provided which is pressed after the tool holder receptacle with hot tool holder has been introduced into the cooling device, as a result of which the means for transporting and the means for cooling are activated. A fully automatic operation, in turn, could be facilitated by appropriate sensor technology that detects the introduction of a tool holder receptacle into the cooling device.

The means for transporting the tool holder receptacles through the device can be in an essentially linear first transport direction, as a result of which the device can have a particularly slim structure. If the device needs to be more compact, it is advantageous if the means for transporting the tool holder receptacles through the device in an essentially circular first transport direction.

If cooling liquids are to serve as coolant, it is furthermore advantageous to provide means for drying the cooled tool holder and to implement the means for cooling and drying in isolated areas of the device separate from each other as cooling station and drying station. As a result, the cooling efficiency of the device increases, because a tool holder is cooled in the cooling station at the same time as a tool holder can be dried in the drying station.

In an embodiment of the present invention, means of detecting temperature are provided, with the aid of which the temperature of the tool holder can be determined and, in accordance with the temperature observed, the means for activation can be controlled, such that the means of cooling can selectively release the coolant.

In another embodiment, the device can have a parking station and possibly a transfer station to the parking station, in which tool holder receptacles with cooled or cooled and dried tool holders are stored prior to removal from the cooling device. This parking station makes it possible for several tool holders to be cooled in direct succession by the cooling device, even when they are not removed from the cooling device by the operating personnel directly.

In the same measure, the cooling station can be preceded by a feed station, in which one or more tool holder receptacles can be stored temporarily before cooling.

In this regard, the transport directions in the feed station and/or the parking station can be different from the first transport direction, because that enables the cooling device to be kept very compact. It is contemplated that these two transport directions can be flexibly adjusted to the local conditions of the installation site of the cooling device.

In a particularly simple manner, the means for transporting can be realized by one or more chains or conveyors, which have dogs for the tool holder receptacles. On the other hand, gripper devices can also be provided, which are arranged to the side or above the transport direction and either are traversable in the transport direction or one gripper device each is assigned to one station, and two, with respect to the transport direction, neighboring gripper devices each forwarding one tool holder receptacle.

To essentially suppress escape of coolant, which usually contains water and rust inhibitor, or its vapors into the vicinity of the cooling device, it is preferable for at least the cooling station, especially the drying station as well, to have appropriate means of shielding. Such shielding means can consist of gas-tight and water-tight containers. Where applicable, appropriate waste and return means for catching the coolant can be provided on the lower side of the container.

Accordingly, suitable means for extracting vapors can be attached to the container walls as well.

For the purpose of facilitating transporting of the tool holder receptacles through such a shielded device, openable shielding doors can be provided at various points, said doors being closed when the device is in operation and capable of being opened during guiding. This allows the container to always remain at the cooling device. In particular, such doors can be provided before and after the cooling station, after the drying station and after the transfer station.

The cooling equipment as well as the drying agent can be designed as a ring with several spray elements, which are vertical relative to the tool holder and can be raised and lowered essentially concentrically with this. This makes for particularly uniform cooling and drying of the tool holder. To control the cooling and drying equipment in their vertical motion, suitable sensors can be provided that detect the contour of the tool holder.

Alternatively, the cooling and drying equipment can also be designed as spray elements, which, relative to the first transport direction, are arranged on both sides of the tool holder. This variant has a very simple design. The coolant spray elements can be arranged radially on the tool holder to optimize the cooling effect. In this variant, too, the spray elements can be traversed vertically or several spray elements can be arranged vertically above each other.

Accordingly, the inventive cooling method includes the cooling of a tool holder with a coolant and the transporting of one or more tool holder receptacles simultaneously in succession, with the method being performed with a device in accordance with the above description. In this regard, the coolant can be a liquid coolant, which is sprayed onto the tool holder, and, after the cooling step, a drying step occurs, in which the tool holder is sprayed with compressed air. The compressed air creates a kind of wiping effect that wipes, and thus dries, the coolant from the tool holder(e.g., vertically downwards).

The tool holder receptacles can be transported either continuously without interruption through the device or periodically, such that for every period, at least one tool holder receptacle is located in a station of the device and, in between periods, at least one tool holder receptacle is transported from one station to the next one in succession. The shielding doors between individual stations can be opened in between periods, with especially only those shielding doors being opened which the tool holder receptacles have passed. For this purpose, it is sensible to provide appropriate sensors, which determine whether or not the tool holder receptacles are about to pass shielding doors.

In an alternative embodiment of the present invention, the device for cooling tool holders with shrink fit chucks, which are accommodated in a tool holder receptacle, comprises means for spraying the tool holder with coolants(e.g., in liquid form), means for transporting the tool holder receptacle and means for activating the means for cooling and the means for transporting. In this regard, the means for transporting are adapted for simultaneously transporting several tool holder receptacles through the device in succession. As has already been explained, the means for transporting the tool holder receptacles can ensure that not just one tool holder receptacle but several tool holder receptacles can be simultaneously transported through the device in succession and thus it is no longer necessary as it was before to await the cooling process in one tool holder until a further tool holder can be transported by hand to such a cooling device. The inventive cooling device is therefore much more efficient and allows the cooling process for a succession of several tool holders to be automated. Advantageously, the means for transporting transports the tool holder receptacle essentially vertically through the device, as the design effort can also be kept low in this way.

Further advantages, characteristics and features of the present invention become clear from the following description in connection with the figures.

FIG. 1 is a first embodiment of the present invention schematically in a vertical cross-sectional illustration;

FIG. 2 is a device in accordance with FIG. 1 together with a shrinking device in a perspective overall view;

FIG. 3 is a second embodiment of the present invention schematically in a vertical cross-sectional illustration; and

FIG. 4 is the device in accordance with FIG. 3, together with a shrinking device in a perspective overall view.

The inventive cooling device 1 shown in a purely schematic plan view in FIG. 1 comprises a container 2, inside of which are arranged a feed station 3, a cooling station 4, a drying station 5, and a transfer station 6. Outside the container 2 connecting to the transfer station 6 is a parking station 7, which is capable of receiving two tool holder receptacles 8a, 8b. At the feed station 3 and the transfer station 6 are doors 9, 10, which are provided for closing the container 2 during operation of the cooling device but which can however be opened for loading and transferring the tool holder receptacles 8a, 8b, 8c, etc.

For transporting the tool holder receptacles 8a, 8b, 8c, etc. inside the cooling device 1 is provided a means for transporting 11 in the form of a chain with dogs. Inside the container 2, the chain 11 runs in a first transport direction and branches inside the transfer station 6 into a transport direction perpendicular to that. In this way, as clearly shown in FIG. 2, the cooling device is optimally adapted geometrically to a shrinking device 12 of known type, as a result of which both devices 1, 12 can be arranged so as to save as much space as possible.

During operation of the cooling device 1, a tool holder receptacle 8g, in which a tool holder 13, which is hot due to the shrinking process, and the tool 14 clamped therein, is transported through the door 9 of the feed station 3. Door 9 is either opened by actuating the push button of a corresponding opening mechanism or opening occurs independently by means of suitable sensor detection. After the door 9 has been closed again either at the press of a button or automatically, the tool holder receptacle 8f is transferred at the press of a button or automatically into the cooling station 4 by means of the chain, although if another tool holder receptacle 8c happens to be in the transfer station 6, door 10 opens at the same time and this tool holder receptacle 8c is transferred into the parking station 7. After the door 10 has been closed at the press of a button or automatically, the container 2 on this side too is sealed off, with the container 2 sealed such that no coolant or coolant vapor can escape outside into the vicinity of the cooling device 1, and the cooling process can begin.

For this purpose, as with all previous and following actions, the action can be started at the press of a button or automatically, which is why no further mention is made of this action. For the cooling process inside the cooling station 4, coolant spray nozzles 15 are arranged radially such that they point towards the tool holder, said nozzles cooling the tool holder 13 by spraying with coolant. To optimize the cooling process, a temperature sensor (not shown) may be provided that detects the temperature of the tool holder 13 and suitably controls spraying with coolant. Furthermore, especially in the case of long tool holder receptacles 13, several coolant spray nozzles 15 can be provided vertically above each other, or such that the coolant spray nozzles 15 are arranged in a plane and can be vertically raised and lowered together.

After the cooling process has been completed, the tool 14 is clamped firmly against rotation in the tool holder 13, the tool holder receptacle 8e is transferred from the cooling station 4 into the drying station 5 where laterally attached compressed-air jets 3, 6 blow the coolant off the tool 14 and tool holder, such that these are dried. Following completion of drying, the tool holder receptacle 8d is transferred into the transfer station 6 and, after opening of the door 10, into the parking station 7, where it can be removed by the operating personnel.

All processes just described occur periodically in the cooling device 1, i.e. while tool holder receptacle 8a, 8b, 8c, etc. is in one of the stations 3, 4, 5, 6 inside the container 2 of the cooling device 1, no further transfer of tool holder receptacles 8a, 8b, 8c, etc. takes place between the individual stations 3, 4, 5, 6, 7.

FIGS. 2 and 3 show further purely schematic embodiments of the inventive cooling device 20. This also has a closed container 21, in whose interior is a cooling station 22, a drying station 23 and a transfer station 24. Transporting within the container 21 is effected by means of a turntable 25, which, over its axis of rotation 26, has continuous walls 27, 28 arranged at right angles to each other like a cross, each of which shields the individual stations 22, 23, 24 from each other and the cooling station 22 and the transfer station 24 from the feed station 29. This ensures that cooling liquid and vapor from the cooling station 22 cannot be transferred into the other stations or the vicinity of the cooling device 20 during the cooling process.

The cooling station 22 and the drying station 23 contain an arrangement of ring elements 30, 31 on vertical linear guides 32, 33, which, at regular distances, have inwardly pointing coolant spray nozzles 34 or compressed-air spray nozzles 35. By means of the linear guides 32, 33, the rings 30, 31 can be raised and lowered concentrically with the tool holders 36 and the tools 37, and thus the cooling process or the drying process can be performed optimally.

During operation of the cooling device 20, a tool holder receptacle 38a, in which is located a tool holder 36 with shrunk fit tool 37, is transferred to the feed station 29 on the turntable 25. Thereafter, the turntable is rotated in 90″ increments into the cooling station 22, from there into the drying station 23 and, after drying has taken place, into the transfer station 24. From the transfer station 24, the tool holder receptacle 38d is transferred by suitable means for transporting 39, after door 40 has opened, into the parking station 41, with, for the sake of simplicity in FIG. 4, only one tool holder 38e being illustrated compared with the two tool holder receptacles 38e, 38f shown in FIG. 3. Thus, the tool holder receptacles 38a, 38b, 38c, etc. pass successively from an established shrinking device 42 and periodically through the cooling device 20 and can be removed from the parking station 41 by the operating personnel.

From the above description, it has become clear that, with the help of the inventive cooling device 1, 20 and the inventive method for cooling a tool holder with shrink fit chucks, an especially efficient, above all fully automatable cooling can be achieved, which also permits cooling of several tool holders 13, 36 in succession. In this regard, the cooling device 1, 20 is not only very economical but it can be designed such that it is perfectly adapted to local spatial conditions and existing shrinking devices 12, 42.

The above description is considered that of the preferred embodiment(s) only. Modification of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiment(s) shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.