Improved fixing device for lathe tool holders

Abstract

The present invention provides an improved device for securing tool holders in lathes, particularly in revolver lathes, CNC lathes, transfer machines, all types of milling centers, and machine tools in general that perform cutting operations, for the rapid and precise securing and release of tools. [Solution] The system consists of a lead screw (12) and a locking claw (14) that engage coaxially with each other, is inserted into an opening (22) of the support, and is oriented perpendicular to the tool holder (44). The lower end of the locking claw (14) is provided with a recess that is shaped to be rotatably engaged with a complementary recess (42) formed along the rear part (54) of the tool holder (44).

Description

Summary of the Invention

[0001] The present invention relates to an improvement in a fixing device for a tool holder in a lathe.

[0002] More specifically, the present invention relates to an improved device for quickly and accurately fixing (blocking) an electric or non-electric tool holder (tool holder). In particular, but not limited to, it is suitable for use in a turret lathe, and the improved device is composed of a carriage equipped with a rotary turret. The turret is suitable for supporting various tools for the workpiece to be processed. The device of the present invention can be applied in any case to CNC lathes, transfer machines, machining centers, all types of milling machining centers, and generally machine tools for cutting operations.

[0003] As is well known, various lathe tools are combined with specific tool holders. These are inserted into the support part of the lathe body at any time. The need to repeatedly replace these tools means an interruption in the production cycle because it requires laborious operations for tool release and replacement, and for fixing and centering the replacement tools to be attached.

[0004] Patent EP3357638, filed by the same applicant, describes a favorable solution to overcome the above-mentioned drawbacks. According to this solution, a device equipped with a locking claw (also called a mooring claw or anchoring claw) at one end of a frustoconical base enables quick, easy, and accurate connection. The locking claw is inserted into a tool holder support on a lathe. A similarly frustoconical collar mounting portion formed on the tool holder engages with the frustoconical base. Manufactured based on the aforementioned European patent, the device enables quick and easy replacement and centering of tool holders in lathes, particularly CNC lathes. In revolver lathes (rotary lathes) with multiple tools mounted on a rotary turret, the device faces inherent limitations due to its overall size, particularly in relation to the support on the lathe. Indeed, the tool holder support needs to be large enough to accommodate two consecutive openings extending vertically along the longitudinal axis of the support, allowing the fixing device and the actuation mechanism to be engaged with each other. This structural arrangement requires considerable space, so only a limited number of tool holders can be installed on the turret of a revolver lathe. However, it is desirable to equip the turret of a revolver lathe with a large number of tool holders and associated tools, in order to enable various necessary machining operations on the workpiece (object) to be performed without interruption.

[0005] The objective of this invention is to solve the aforementioned drawbacks.

[0006] More specifically, the objective is to provide a device for fixing tool holders in the turret of a general-purpose lathe, particularly a revolver lathe.

[0007] Furthermore, the present invention aims to provide a fixing device as defined above, which enables the tool holder to be quickly and easily attached to and removed from a general turning machine, particularly a turret of a revolver lathe.

[0008] Furthermore, the present invention aims to provide users with a fixing device for tool holders on a lathe. This device ensures high strength and reliability over a long period of time, while also being easy and economical to manufacture.

[0009] These and other objectives are achieved by the lathe tool holder fixing device of the present invention, in accordance with the main claim.

[0010] The structural and functional features of the lathe tool holder fixing device of the present invention can be better understood from the following detailed description. The following description refers to the accompanying drawings illustrating preferred but not limited embodiments. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic exploded view showing the apparatus, tool holder, and relative support portion provided on the lathe according to the present invention. [Figure 2] Figure 2 is a schematic diagram showing a perspective view of the tool holder from a different angle than that shown in Figure 1. [Figure 3] Figure 3 is a schematic isometric projection of the components of Figure 1 that are designed to work in cooperation with the locking claws. [Figure 4] Figure 4 is a schematic diagram of the isometric projection of the locking claw. [Figure 5] Figure 5 is a schematic diagram of the locking claw rotated 180 degrees relative to Figure 4. [Figure 6] Figure 6 is a schematic diagram showing a vertical cross-section of the lathe support section shown in Figure 1, incorporating the fixing device of the present invention. [Figure 7] Figure 7 is a schematic diagram showing an exploded view of a possible solution, which includes the fixing device of the present invention and a disc-shaped body with multiple seats for the same number of tool holders.

[0012] Referring to Figure 1, the improved apparatus of the present invention is suitable for fixing tool holders on numerically controlled machines called transfer machines or machining centers. In the embodiments described herein, the tool holder fixing device is integrated into a support shown as 10 in Figure 1, which is located, for example, on the turret of a revolver lathe. The configuration of the support 10 in Figure 1 is merely an example. Alternatively, a single disk of appropriate height can be provided with multiple seats around its periphery, to accommodate multiple fixing devices in combination with the same number of tool holders, as shown in Figure 7.

[0013] According to the present invention, the fixing device includes a lead screw 12 having a trapezoidal thread 12' (Figure 3) on its exterior, and a substantially cylindrical claw 14. The cylindrical claw 14 has a vertically extending recess 16 on its exterior for positioning a centering and anti-rotation pin 18. The claw 14, shown in detail in Figures 4 and 5, is provided with a vertically extending hole 20. The hole 20 has threads that engage with the threads of the lead screw 12. The latter screws into the hole 20 of the claw 14. This creates a coaxial restraining force between the two components. The upper base of the support 10 is provided with an opening 22 that extends to a semicircular attachment 24. This allows the centering pin 18 to pass through when the coaxially fitted claw 14 and lead screw 12 are inserted into the support 10 through the opening 22. A bushing 26 is fitted onto the upper part of the lead screw 12. A recess 28 is provided on its periphery, where a centering pin 18 is positioned. A groove 30 is provided on the shaft of the lead screw 12. The groove 30 extends above the external trapezoidal thread 12'. The groove 30 is for positioning a sieger ring 32, which prevents the lead screw 12 itself from falling out axially. The latter and the claws 14, which mesh coaxially with each other, are separated at the top and bottom by O-rings 34 and 36, respectively. This prevents tool coolant and impurities from entering the claws 14. The plate 38 closes the opening 22 of the support 10 by a screw 50. The free end of the lead screw 12 protrudes from a hole provided in the same plate 38. The lead screw is actuated preferably manually, or optionally by electrical means, to move the locking claws 14 vertically.

[0014] The aforementioned claws, similar to the solution described in EP3357638, are provided with a female frustoconical recess 40. This is designed to engage with a male inclined frustoconical projection 42 formed on the tool holder. The latter is schematically shown as 44 in Figures 1, 2, and 6 and fits into a seat (also called a seat) 46 formed on the support 10. This seat is positioned perpendicular to the opening 22. The opening 22 receives claws 14 and lead screws 12 that engage coaxially with each other. On a single disk shown as 60 in Figure 7, it is possible to provide multiple seats 46 corresponding to multiple tool holders 44. Furthermore, there are multiple openings 22 for accommodating corresponding fastening devices. These consist of lead screws 12 and claws 14 that are coaxial with each other.

[0015] The claw 14 consists of a substantially cylindrical body. It has a radial cutout at its lower end. The remaining radial portion (indicated as 48 in Figure 4) defines a vertical wall 48'. A female frustoconical recess 40 is formed in this wall. At the same time, the tool holder 44 is provided with a male frustoconical recess 42, which is formed in the rear wall indicated as 54 in Figures 1 and 2. This constitutes a mounting portion for connection to a lathe. Preferably, the frustoconical recess 42 of the tool holder 44 is formed by double vertical holes of different diameters. This forms a collar-like attachment 56 (Figures 2 and 6). This is designed to fit into the frustoconical recess 40 of the locking claw 14. The latter moves up and down by the rotation of a coaxially fitted lead screw 12. This rotation can be performed using a conventional manual wrench or an electric actuator. When lowered, the locking claw 14 fixes the tool holder 44, as shown in Figure 6. This is because the frustoconical collar attachment 56 of the latter tool holder 44 is located adjacent to the female frustoconical recess 40 of the same locking claw 14. The attachment 56 is separated by the recess 40 when the lead screw 12 is rotated in one direction, causing the tool holder 44 to be fixed in place. Conversely, when the lead screw 12 is rotated in the opposite direction, the locking claw 14 is lifted as the frustoconical collar attachment 56 disengages from the recess 40. This allows the tool holder 44 to be removed and replaced.

[0016] As is clear from the above, the advantages achieved by the present invention are remarkable.

[0017] The improved device of the present invention is suitable for securing tool holders in lathes, both revolver and CNC machines, transfer machines, all types of milling centers, and machine tools that perform cutting operations in general. The locking claws 14 coaxial with the lead screw 12 allow for quick and easy replacement while significantly reducing the overall dimensions of the tool holder 44. The limited space required for installing the fixing device of the present invention advantageously allows for installation on a single disc-shaped support 60 (Figure 7), which has multiple seats 46 for various tool holders 44 and an equal number of openings 22 capable of accommodating locking claws 14 axially connected to the lead screw 12.

[0018] The present invention is described above with reference to specific embodiments for illustrative and limiting purposes. However, given the above disclosure, a number of modifications and variations will be readily apparent to those skilled in the art. Accordingly, the present invention is intended to encompass all modifications and variations that fall within the spirit and scope of the following claims.

Claims

1. An improved device for securing tool holders in lathes, particularly in revolver lathes, CNC lathes, transfer machines, all types of milling centers, and machine tools in general that perform cutting operations, for the rapid and precise securing and release of tools. A tool holder (44) is inserted into a seat (46) of a support (10) or (60) provided on the lathe and machine tool, and cooperates with the tool holder (44). It consists of a lead screw (12) and a locking claw (14) that engage with each other coaxially, It is inserted into the opening (22) of the support (10) or (60) and oriented perpendicular to the tool holder (44), An improved device, wherein the lower end of the locking claw (14) is provided with a recess (40) shaped to be rotatably engaged with a complementary recess (42) formed along the rear portion (54) of the tool holder (44).

2. The lead screw (12) is provided with an external trapezoidal screw 12' for engaging with the locking claw (14), The locking claw (14) is provided with a hole (20) extending in the vertical direction. The aforementioned hole (20) has threads that are complementary to the threads of the lead screw (12). The device for fixing according to claim 1.

3. A vertically extending recess (16) is provided on the outside of the locking claw (14) for positioning a centering positioning and rotation prevention pin (18). The openings (22) of the support bodies (10) and (60) extend to a semicircular attachment (24) through which the centering pin (18) passes when the claws (14) and the lead screw (12) are inserted into the support bodies with the claws (14) and the lead screw (12) interlocking coaxially with each other. The device for fixing according to claim 2.

4. A bushing (26) is provided on the upper part of the lead screw (12). The bushing (26) has a peripheral recess (28), In the peripheral recess (28), the centering positioning and rotation prevention pin (18) is positioned. A groove (30) is provided on the shaft portion of the lead screw (12) and above the outer trapezoidal thread (12') for positioning the seager ring (32). The seagull ring (32) prevents the lead screw itself from falling out in the axial direction. The device for fixing according to claim 2.

5. The lead screw (12) and the claw (14), which mesh coaxially with each other, are separated at their upper and lower parts by O-rings (34) and (36), respectively. The device for fixing according to claim 2.

6. The recess (40) has a female-type frustoconical shape and is formed on the vertical wall (48') of the radial portion (48) of the claw (14). The device for fixing according to claim 1.

7. The tool holder (44) has a male frustoconical recess (42) provided at its rear (54), The male frustoconical recess (42) is formed by two vertical holes of different diameters. This forms a collar attachment (56) that can engage with the female frustoconical recess (40) of the locking claw (14). The device for fixing according to claim 1.

8. The opening (22) of the support (10) is closed by a plate (38) with a screw (50), The free end of the lead screw (12) protrudes from the plate, and the latter is operated manually or electrically. The device for fixing according to claim 1.

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