CHUCKS FOR MOUNTING ROUND AND RECTANGULAR

WORKPIECES

The subject of the invention are chucks for mounting round and rectangular workpieces attached to reference elements of various clamping systems. The invention falls into the class B 23H 7/26 of the International Patent Classification. The technical problem these chucks seek to solve is mounting round and rectangular workpieces by means of a chuck with bearing surfaces, which determine the position of the workpiece and a flexible element, which enables the mounting of the workpiece on the chuck, which is made in one piece. Modern technologies enable production of such clamping devices at a relatively low cost.

The chucks are intended for mounting smaller electrodes to modern devices for immersion machining by electro-erosion with changers for automatic electrode changing. Hydraulic chucks provide the solution for mounting only round electrode holders, which are carried out in sufficiently tight tolerances (for instance chucks from the Swedish 3R Mini system and chucks from the Swiss Mecatool GPS 20 system). Rectangular shapes can be mounted with the help of the Swiss solutions Erowa marked ER-010607, ER-032810 etc that enable mounting of electrode holders or appropriately machined blanks for producing

electrodes from copper or graphite. These chucks can be reused several times. When using the electrode changer you need to purchase a greater quantity of chucks, which means bigger expenses.

The said chucks according to the invention are much cheaper and shall not exceed 15 to 20% of the price of previously mentioned chucks. These chucks can also be reused; the expenses are therefore smaller due to the lower price of the chucks.

The chuck embodiments shall be explained in detail with the help of drawings of which:

Figure 1 depicts the chuck embodiment for mounting round workpieces with a flexible element in the form of a cantilever;

Figure 2 depicts the chuck embodiment for mounting round workpieces with a flexible element in the form of a double- sided support;

Figure 3 depicts the chuck embodiment for mounting round workpieces with a flexible element in the form of a single- sided support;

Figure 4 depicts the chuck embodiment for mounting round workpieces with a flexible element in the form of a cantilever and sprocket for preventing rotation;

Figure 5 shows the chuck embodiment for mounting rectangular workpieces with a flexible element in the form of a cantilever;

Figure 6 shows the chuck embodiment for mounting rectangular workpieces with a flexible element in the form of a double- sided support;

Figure 7 shows the chuck embodiment for mounting rectangular workpieces with a flexible element in the form of a single- sided support;

The chuck for mounting round workpieces according to this invention is shown on Figure 1. It allows mounting of round shapes with a nominal dimension A with the maximum deviation ± dA, which depends on the size of the gap between the basic element 1 and the flexible element 5. The chuck consists of the basic element 1 , where the borehole and three bearing surfaces 6, 7, 8 are located. The said bearing surfaces 6 and 7 are fixed to the basic element 1 , whereas bearing surface 8 is flexible on the flexible element 5. When mounting the workpiece the said workpiece shall be inserted into the borehole with a loose screw 4. Proceed by mounting the workpiece with adequate force gained from the fixing of screw 4. The mounting force is transmitted via the disc spring 3 and ball 2 to the flexible element 5. It is possible to make embodiments, where the mounting force is transmitted to the flexible element from screw 4 to ball 2 or an embodiment, where the force is transmitted from screw 4 directly to flexible element 5. The flexible element 5 is connected to the basic element 1 through cantilever 5'. The movement is limited by the size of the gap between the fixed element 1 and the flexible element 5. The

maximum movement is achieved, when the cantilever 5' bears on surface V on the basic element 1 and the sprocket 5" on surface 1" on the basic element 1. To unmount the workpiece screw 4 shall be unscrewed. The force resulting from the deformation of cantilever 5' moves the flexible element 5 and allows removing the workpiece from the borehole on the fixed element 1.

Another embodiment of the chuck for mounting round workpieces according to this invention, is shown on Figure 2. It enables mounting of round shapes with a nominal dimension A with the maximum deviation ± dA, which depends on the size of the gap between the basic element 1 and the flexible element 5. The chuck consists of the basic element 1 , where the borehole and three bearing surfaces 6, 7, 8 are located. The said bearing surfaces 6 and 7 are fixed, whereas bearing surface 8 is flexible on the flexible element 5. When mounting the workpiece the said workpiece shall be inserted into the borehole with a loose screw 4. Proceed by mounting the workpiece with adequate force gained from fixing of screw 4. The mounting force is transmitted via the disc springs 3 and ball 2 to the flexible element 5. It is possible to make embodiments, where the mounting force is transmitted to the flexible element from screw 4 to ball 2 or an embodiment, where the force is transmitted from screw 4 directly to flexible element 5. The flexible element 5 is connected to the basic element 1 through a double-sided support 15' - 15". The said support is designed to enable adequate movement of the flexible element 5. The movement is limited by the size of the gap between the fixed

element 1 and the flexible element 5. The maximum movement is achieved, when the first part of the double-sided support bears on the surface 11' on the basic element 1 with the part 5' and the other part of the double-sided support 15" bears on surface 11" on the basic element 1. To unmount the workpiece screw 4 shall be unscrewed. The force resulting from the deformation of the double-sided support 15'-15" moves the flexible element 5 and allows removing the workpiece from the borehole on the fixed element 1.

The third embodiment of the chuck for mounting round workpieces according to this invention, is shown on Figure 3. It enables mounting of round shapes with a nominal dimension A with the maximum deviation ± dA, which depends on the size of the gap between the basic element 1 and the flexible element 5. The chuck consists of the basic element 1 , where the borehole and three bearing surfaces 6, 7, 8 are located. The said bearing surface 6 and 7 are fixed, whereas bearing surface 8 is flexible on the flexible element 5. When mounting the workpiece the said workpiece shall be inserted into the borehole with a loose screw 4. Proceed by mounting the workpiece with adequate force gained from fixating screw 4. The mounting force is transmitted via the disc springs 3 and ball 2 to the flexible element 5. It is possible to make embodiments, where the mounting force is transmitted to the flexible element from screw 4 to ball 2 or an embodiment, where the force is transmitted from screw 4 directly to flexible element 5. The flexible element 5 is connected to the basic element 1 via a single-sided support 25' - 25". The said support is

designed so that element 25' is connected to basic element 1 and element 25" leans on pivot 9, which is force-fitted into basic element 1 and enables movement of element 25" of the support in longitudinal direction. The movement is limited by the size of the gap between the fixed element 1 and the flexible element 25. The maximum movement is achieved, when the first part of the double-sided support bears on the surface 21' on the basic element 1 with the part 25' and the other part of the double-sided support 25" bears on surface 21" on the basic element 1. To unmount the workpiece screw 4 shall be unscrewed. The force resulting from the deformation of the double-sided support 25'-25" moves the flexible element 5 and allows removing the workpiece from the borehole on the fixed element 1.

The fourth embodiment of the chuck is presented on Figure 4. It is designed to mount workpieces from softer materials such as copper, graphite, aluminium etc. The said embodiment has a sprocket 10 that is force-fitted into the workpiece while mounting it, on the flank opposite to the flexible element. The height of the sprocket Z that is force-fitted into the workpiece must be such that the said workpiece bears on the said surfaces 6 and 7. The fitted sprocket increases the moment leading to the rotation of the workpiece. Figure 4 presents an embodiment with a cantilever as the flexible part. The sprocket embodiment can be also deployed in embodiments with double-sided mounting (Figure 2) and single-sided mounting (Figure 3).

The chuck for mounting rectangular workpieces according to this invention is depicted on Figure 5. The said chuck enables mounting of said rectangular shapes with a nominal dimension B. One edge of the said rectangular form is cropped to the length of the diagonal C with a maximum deviation of ± dC that depends on the size of the gap between basic element 1 and flexible element 5. The chuck comprises the basic element 1 with borehole and four bearing surfaces 6', 6", 7, 8. The said bearing surfaces 6', 6" and 7 are fixed, while bearing surface 8 is flexible. While mounting the workpiece, the said workpiece is inserted into the borehole with a loose screw 4. Mount the workpiece with adequate force gained from fixating the said screw 4. The mounting force is transmitted via the disc springs 3 and the ball 2 to flexible element 5. The mounting force can be transmitted to the flexible element 5 from screw 4 to ball 2 or from screw 4 directly to flexible element 5. The said flexible element 5 is connected to the basic element 1 via cantilever 35'. The movement is limited by the size of the gap between the fixed element 1 and the flexible element 5. The maximum movement is achieved, when cantilever 33' bears on the surface 31' on the basic element 1 and sprocket 35" bears on surface 31" on the basic element 1. To unmount the workpiece screw 4 shall be unscrewed. The force resulting from the deformation of the double-sided support 35'-35" moves the flexible element 5 and allows removing the workpiece from the borehole on the fixed element 1.

Yet another embodiment of the chuck for mounting rectangular workpieces according to this invention is depicted on Figure 6. The said

chuck enables mounting of said rectangular shapes with a nominal dimension B. One end of the said rectangular form is cropped to the length of the diagonal C with a maximum deviation of ± dC that depends on the size of the gap between said basic element 1 and said flexible element 5. The chuck comprises the basic element 1 with borehole and four bearing surfaces 6\ 6", 7, 8. The said bearing surfaces 6\ 6" and 7 are fixed, while bearing surface 8 is flexible. While mounting the workpiece, the said workpiece is inserted into the borehole with a loose screw 4. Mount the workpiece with adequate force gained from fixating said screw 4. The mounting force is transmitted via the disc springs 3 and the ball 2 to flexible element 5. The mounting force can be transmitted to the flexible element 5 from screw 4 to ball 2 or from screw 4 directly to flexible element 5. The said flexible element 5 is connected to the basic element 1 via a double-sided support 45'-45". The latter is designed as to enable adequate movement of the flexible element 45'. The movement is limited by the size of the gap between said fixed element 1 and said flexible element 5. The maximum movement is achieved, when cantilever 45' bears on the surface 41' on the basic element 1 and sprocket 45" bears on surface 41" on the basic element 1. To unmount the workpiece screw 4 shall be unscrewed. The force resulting from the deformation of the double-sided support 45'-45" moves the flexible element 5 and allows removing the workpiece from the borehole on the fixed element 41.

The third embodiment of the chuck for mounting rectangular workpieces according to this invention is depicted on Figure 7. The said

embodiment enables mounting of said rectangular shapes with a nominal dimension B. One end of the said rectangular form is cropped to the length of the diagonal C with a maximum deviation of ± dC that depends on the size of the gap between said basic element 1 and said flexible element 5. The chuck comprises the basic element 1 with borehole and four bearing surfaces 6 ¹ , 6", 7, 8. The said bearing surfaces 6\ 6" and 7 are fixed, while bearing surface 8 is flexible. The workpiece shall be mounted by inserting it into the borehole with a loose screw 4. Mount the workpiece with sufficient force gained from fixating screw 4. The mounting force is transmitted via disc springs 3 and ball 2 to flexible element 55. It is possible to make embodiments, where the mounting force is transmitted to the flexible element 5 from screw 4 to ball 2 or, where the force is transmitted from screw 4 directly to flexible element 5. The flexible element 55 is connected with the basic element 1 via a single-sided support 55'-55". The said support is designed so that element 55' is connected to basic element 1 and element 55" leans on pivot 9, which is force-fitted into basic element 1 and enables movement of element 55" of the support in longitudinal direction. The movement is limited by the size of the gap between the fixed element 1 and the flexible element 5. The maximum movement is achieved, when cantilever 55' bears on the surface 51' on the basic element 1 and sprocket 55" bears on surface 51" on the basic element 1. To unmount the workpiece screw 4 shall be unscrewed. The force resulting from the deformation of the double-sided

support 55'-55" moves the flexible element 5 and allows removing the workpiece from the borehole on the fixed element 1.