Conversion T-Nut

Abstract

To provide a conversion T-nut that enables a top jaw that is not compatible with a lathe chuck to be mounted on a lathe chuck of a different size. [Solution] By providing a step in the T-nut 3C, a component of the machine tool chuck, the machine tool chuck can use top jaws 2a of different sizes for the chuck to be used. Furthermore, there is no need to prepare multiple top jaws for each chuck size, which can drastically reduce the manufacturing cost, time, and storage cost of the top jaws. In addition, by providing a C-chamfered shape on the head and ridges on the depth side of the T-nut, it can be moved to the very end face of the center of the master jaw, and by providing an arc R shape on the head and ridges on the depth side of the T-nut, it can be moved to the very end face of the center of the master jaw.

Description

[Technical field]

[0001] This invention relates to a machine tool chuck, which is used when mounting a workpiece on a machine tool. [Background technology]

[0002] Generally, when a workpiece is mounted on a machine tool such as a lathe, the workpiece is held and fixed by a chuck. The chuck is mainly composed of a top jaw that holds a workpiece, a T-nut that can be fitted to the top jaw, a master jaw that can be fitted to the T-nut, and a chuck body to which the master jaw is attached. Each component part of this chuck comes in a set for each chuck size, and since they are dedicated to each size, they are not interchangeable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2000-288809 Summary of the Invention [Problem to be solved by the invention]

[0004] Each component part of the chuck comes in one set for each chuck size, such as 6 inches, 8 inches, 10 inches, etc., and the T-nuts for attaching the top jaws to the chuck are determined according to the chuck size. For example, a T-nut for an 8-inch chuck is only for 8 inches, and cannot be used for other sizes. However, it is customary to use top jaws with holding parts machined into shapes that make them easy to hold for each workpiece, and machining all top jaws for each size is time-consuming, which leads to a relative increase in costs.

[0005] The head and ridges of the T-nut are angular, so when they are fitted together, the amount of movement is limited and it is difficult to reach the center of the chuck inside the master jaw, so a separate process has to be added, which takes time. [Means for solving the problem]

[0006] By providing a step to the T-nut, a component of the machine tool chuck mentioned above, it is possible to use top jaws of different sizes for the chuck to be used, thus solving the above-mentioned drawbacks. Furthermore, it is no longer necessary to prepare multiple top jaws for each chuck size, which allows for a dramatic reduction in the manufacturing cost, time, and storage cost of the top jaws.

[0007] By providing a C-chamfered shape on the head and ridgeline on the depth side of the T-nut, a component part of the machine tool chuck described above, it is possible to move the master jaw to the very end face in the center.

[0009] By providing an arc-shaped R-shape on the head and ridgeline on the depth side of the T-nut, a component part of the machine tool chuck mentioned above, it is possible to move the master jaw to the very end face in the center. Effect of the Invention

[0010] In the invention of claim 1, in the aforementioned machine tool chuck, the T-nut, which is a component thereof, has a step in the body that is parallel to the jaw portion toward the depth direction, forming a narrow portion on the head side and a wide portion on the tail side, so that the narrow portion of the T-nut abuts against and fits into the recess of the master jaw, and the wide portion of the T-nut abuts against and fits into the recess of the top jaw. This makes it possible to use the top jaw in chucks made for sizes other than the specific size, and eliminates the need to machine the top jaw for each size, making it possible to reduce costs and conserve and make effective use of resources.

[0011] In the invention of claim 2, in the aforementioned machine tool chuck, the T-nut, which is a component thereof, has a step in the body that is parallel to the jaw portion toward the depth direction, so that a wide portion is formed on the head side and a narrow portion is formed on the tail side. The wide portion of the T-nut abuts against and fits into the recess of the master jaw, and the narrow portion of the T-nut abuts against and fits into the recess of the top jaw. This makes it possible to use the top jaw in chucks made for sizes other than the specific size, and eliminates the need to machine the top jaw for each size, making it possible to reduce costs and conserve and make effective use of resources.

[0012] In the invention of claim 3, in the above-mentioned machine tool chuck, the T-nut, which is a component part thereof, is provided with a C-chamfered shape on the ridge at the deepest end of the head, thereby increasing the amount of movement to the center of the chuck, making it easier to hold and process small workpieces, and reducing one process step, resulting in a time saving.

[0013] In the invention of claim 4, in the above-mentioned machine tool chuck, the T-nut, which is a component part thereof, is provided with an arc-shaped R-shape on the ridgeline at the deepest end of the head, thereby increasing the amount of movement to the center of the chuck, making it easier to hold and process small workpieces, and reducing one process step, resulting in a time saving. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an embodiment of a conventional machine tool chuck. [Diagram 2] FIG. 1 is a front view of an example of a T-nut and its surroundings that can be used in a conventional 8-inch machine tool chuck, taken along the line A. [Diagram 3] FIG. 1 is a front view of an example of a T-nut and its surroundings that can be used in a conventional 6-inch machine tool chuck, taken along the line A. [Figure 4] FIG. 11 is a front view showing another example of a T-nut and its surroundings that can be used in the machine tool chuck according to the present invention. [Diagram 5]FIG. 11 is a front view showing another example of a T-nut and its surroundings that can be used in the machine tool chuck according to the present invention. [Figure 6] FIG. 1 is a perspective view of a T-nut that can be used in the machine tool chuck of the present invention, with a chamfered tip portion. [Figure 7] FIG. 1 is a perspective view of a T-nut that can be used in the machine tool chuck of the present invention, with an R-shaped tip portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the machine tool chuck according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of a conventionally known machine tool chuck. The machine tool chuck 1 has a top jaw 2 for holding a workpiece, a T-nut 3 that can be fitted to the top jaw 2, a master jaw 4 that can be fitted to the T-nut 3, and a cylindrical chuck body 5 to which the master jaw 4 can be attached in a radial direction. The top jaw 2, the T-nut 3, the master jaw 4, and the chuck body 5 are provided as a set for each specific size. The top jaw 2, the T-nut 3, and the master jaw 4 are combined with each other to form a set, and are attached to one end surface side of the chuck body 5 at equal intervals of 120°. The workpiece is fixed in a state in which it is sandwiched at the center position on the inner periphery side of the chuck body 5 by the inner ends of the three top jaws 2, or is pushed out in the radial direction on the outer periphery side of the chuck body 5 by the outer ends of the three top jaws 2.

[0016] Each component of the conventional machine tool chuck having such a configuration was provided in one set for each chuck size, such as 8 inches, 6 inches, etc. FIG. 2 shows an example of an 8-inch chuck section as viewed from the arrow A, and FIG. 3 shows an example of a 6-inch chuck section as viewed from the arrow A. As shown in FIGS. 1 and 2, the top jaw 2a is a processed rectangular metal, and two screw insertion holes 6a, 6a are provided on the center line of the upper surface in the longitudinal direction (the direction perpendicular to the paper surface in FIG. 2). In addition, a recessed portion 7a is provided over the entire length of the lower surface on the center line in the longitudinal direction. The width of the recessed portion 7a is slightly larger than the width of the tail portion 322a of the T-nut 3a described next.

[0017] The T-nut 3a is composed of a head 31a and a body 32a, the head 31a is provided with a jaw 311a having a surface perpendicular to the side surface 321a of the body 32a, and the body 32a is provided with a tail 322a having a surface parallel to the jaw 311a on the opposite side to the head 31a. The tail 322a has a dimension slightly smaller than the width of the recess 7a, so the tail 322a and a part of the side surface 321a continuing from the tail 322a are fitted into the recess 7a of the top jaw 2a. On the longitudinal center line of the tail portion 322a of the T nut 3a, screw holes 25a, 25a are provided at positions corresponding to the two screw insertion holes 6a, 6a provided in the top jaw 2a. By inserting a screw 26a into the screw insertion holes 6a, 25a and screwing it into the screw holes 25a, 25a, the top jaw 2a and the T nut 3a are attracted to each other, the master jaw 4a is pulled up by the jaw portion 311a of the T nut 3a, and the serrated surface 411a of the master jaw 4a (described later) and the serrated surface 211a of the top jaw 2a are attracted to each other and abut against each other, and the top jaw 2a, the T nut 3a and the master jaw 4a are fixed together.

[0018] The master jaw 4a has protrusions 10a on the left and right sides to prevent it from coming off, which are formed by machining a rectangular metal, and has a recess 8a into which the head 31a of the T-nut 3a and a part of the body 32a continuing from the head 31a can be fitted, and the T-nut 3a is fitted into this recess 8a. The master jaw 4a is fitted into a recess 9a provided on one end face side of a cylindrical chuck body 5a from the outer periphery toward the inner periphery, and is attached so as to be movable within a predetermined range in the radial direction of the chuck body 5a by hydraulic control, for example.

[0019] The upper surface of the master jaw 4a and the lower surface of the top jaw 2a each have a serrated surface 411a, 211a in which peaks and valleys are arranged at a predetermined pitch in the longitudinal direction. Therefore, these serrated surfaces 411a and 211a mesh with each other. When the master jaw 4a is pressed toward the center of the chuck body 5a by air or other pressure, the top jaw 2a is also pressed toward the center of the chuck body 5a, and the workpiece arranged in the center of the chuck body 5a is fixed to the central position of the chuck body 5a. Alternatively, the master jaw 4a moves radially outward from the chuck body 5a together with the T-nut 3a and the top jaw 2a, thereby fixing the workpiece at the outer end of the top jaw 2a.

[0020] Figure 3 shows an example of a 6-inch chuck, and like Figure 2, the machine tool chuck is made up of a set of top jaw 2b, T-nut 3b, master jaw 4b, and chuck body 5b. The example in Figure 3 is almost similar to the example in Figure 2, but the dimensions of each component are smaller than those in the example in Figure 2.

[0021] In this way, the top jaws 2a, T-nuts 3a, master jaws 4a, and chuck body 5a for 8-inch machines come in a set of four, and the top jaws 2b, master jaws 4b, and chuck body 5b for 6-inch machines also come in a set of four, so there is currently no compatibility between them.

[0022] However, it is customary to use top jaws with holding parts machined into shapes that make them easy to hold for each workpiece, and in the past, it was necessary to machine all top jaws for each size, which required a lot of work and increased costs. Therefore, it was desirable to have top jaws that could be used not only for a specific size, but also for chucks of other sizes.

[0023] The present invention has been made to solve the problems of the above-mentioned conventional technology. A specific example of the machine tool chuck according to the present invention will be described below. As shown in Figs. 2 and 3, in the conventional machine tool chuck, the T-nut is composed of a head and a body perpendicular to the head. Therefore, the 8-inch T-nut 3a shown in Fig. 2 and the 6-inch T-nut 3b shown in Fig. 3 are processed to have almost similar shapes. For example, even if the T-nut 3a made for 8 inches is to be fitted to a top jaw and a master jaw for a size larger than 8 inches, the recesses provided in the top jaw and the master jaw are too large to create a gap and cause misalignment, and it cannot be used. On the other hand, even if it is to be fitted to a top jaw and a master jaw for a size smaller than 8 inches, the recesses provided in the top jaw and the master jaw are too small to be fitted. Therefore, in the present invention, by devising the shape of the T-nut, the top jaw can be used not only for a specific size but also for a master jaw and a chuck body of another size.

[0024] First, an example in which a top jaw for a large size can be used for a master jaw and a chuck body for a small size will be shown. The top jaw shown in FIG. 4 is the same as the top jaw 2a for 8 inches shown in FIG. 2, and the master jaw and the chuck body are the same as the master jaw 4b and the chuck body 5b for 6 inches shown in FIG. 3. A step 11 parallel to the jaw portion 311c is provided in the body portion 32c of the T-nut 3c toward the depth direction, and a narrow portion 12 is formed on the head side and a wide portion 13 is formed on the tail side. The width of the narrow portion 12 is equivalent to the width of the body portion 32b of the T-nut 3b for 6 inches shown in FIG. 3, and the width of the wide portion 13 is equivalent to the width of the body portion 32a of the T-nut 3a for 8 inches shown in FIG. 2. Both side surfaces of the narrow portion 12 of the T-nut 3c and the jaw portion 311c abut against and fit into the recessed portion 8b of the 6-inch master jaw 4b, and both side surfaces of the wide portion 13 of the T-nut 3c abut against and fit into the recessed portion 7a of the 8-inch top jaw 2a.

[0025] Therefore, by using the T-nut 3c, the top jaw 2a for 8 inches can be used with the master jaw 4b and the chuck body 5b for 6 inches, as shown in FIG.

[0026] In the above embodiment, an example has been shown in which the 8-inch top jaw 2a is applied to the 6-inch master jaw 4b and chuck body 5b, but by leaving the width of the wide portion 13 of the T-nut 3c as is for 8 inches and setting the dimensions of the head portion 31c and the body portion 32c of the T-nut 3c to, for example, a 4-inch T-nut, it is possible to apply the 8-inch top jaw 2a to a master jaw of an even smaller size. As a result, it is no longer necessary to prepare top jaws of all sizes, the effort required for machining the top jaws is eliminated, and resources can be saved and used effectively.

[0027] Next, an example in which a top jaw for a small size can be used for a master jaw and a chuck body for a large size will be described with reference to FIG. 5. The top jaw shown in FIG. 5 is the same as the top jaw 2b for 6 inches shown in FIG. 3, and the master jaw and the chuck body are the same as the master jaw 4a and the chuck body 5a for 8 inches shown in FIG. 2. A step 14 parallel to the jaw portion 311d is provided in the body portion 32d of the T-nut 3d in the depth direction, and a wide portion 15 is formed on the head side and a narrow portion 16 is formed on the tail side. The width of the wide portion 15 is equivalent to the width of the body portion 32a of the T-nut 3a for 8 inches shown in FIG. 2, and the width of the narrow portion 16 is equivalent to the width of the body portion 32b of the T-nut 3b for 6 inches shown in FIG. 3. Both side surfaces of the wide portion 15 of the T-nut 3d and the jaw portion 311d abut against and fit into the recessed portion 8a of the 8-inch master jaw 4a, and both side surfaces of the narrow portion 16 of the T-nut 3d abut against and fit into the recessed portion 7b of the 6-inch top jaw 2b.

[0028] Therefore, by using the T-nut 3d, the 6-inch top jaw 2b can be used with the 8-inch master jaw 4a and chuck body 5a as well, as shown in FIG.

[0029] In the above embodiment, an example is shown in which the 6-inch top jaw 2b is applied to the 8-inch master jaw 4a and chuck body 5a, but by leaving the width of the narrow portion 16 of the T-nut 3d as is for 6 inches and setting the head 31d and body 32d of the T-nut 3d to the dimensions of a 10-inch T-nut, for example, the 6-inch top jaw 2b can be applied to a master jaw for a larger size. As a result, there is no need to prepare top jaws of all sizes, the effort required for machining the top jaws can be eliminated, and resources can be saved and used effectively.

[0030] In the above embodiment, an example of a three-jaw chuck in which a set of top jaws, T-nuts, and master jaws are attached to one end face of the chuck body at equal intervals of 120° from each other has been described. However, it goes without saying that the design can be appropriately modified to a four-jaw chuck, five-jaw chuck, etc. depending on the size of the chuck, etc.

[0031] Figures 6 and 7 show T-nuts with chamfered and rounded tips. With conventional T-nuts, the jaws had poor access to the center of the chuck body, but this has been improved to bring the top jaws closer to the center. [Explanation of symbols] 2a Top Jaw 3c T-nut 4b Master Joe 5b Chuck body 7a Recess 8b Recess 9a Recess 11 Steps 12 Narrow part 13 Wide section 31c head 32c Torso 311c Jaw 322c tail

Claims

1. A top jaw capable of holding a workpiece and having a recess; a T-nut having a jaw portion and capable of being fitted into the recess of the top jaw; a master jaw having a recess that can be fitted onto the T-nut; In a machine tool chuck having a chuck body to which the master jaw is attached, The T-nut has a body portion having a step parallel to the jaw portion in the depth direction, thereby forming a narrow portion on the head side and a wide portion on the tail side, and the narrow portion of the T-nut abuts against and fits into a recess in the master jaw, and the wide portion of the T-nut abuts against and fits into a recess in the top jaw. This is a chuck for a machine tool.

2. A top jaw capable of holding a workpiece and having a recess; a T-nut having a jaw portion and capable of being fitted into the recess of the top jaw; a master jaw having a recess that can be fitted onto the T-nut; In a machine tool chuck having a chuck body to which the master jaw is attached, The T-nut has a body portion having a step parallel to the jaw portion in the depth direction, thereby forming a wide portion on the head side and a narrow portion on the tail side, and the wide portion of the T-nut abuts against and fits into a recess in the master jaw, and the narrow portion of the T-nut abuts against and fits into a recess in the top jaw. This is a chuck for a machine tool.

3. A top jaw capable of holding a workpiece and having a recess; a T-nut having a jaw portion and capable of being fitted into the recess of the top jaw; a master jaw having a recess that can be fitted onto the T-nut; In a machine tool chuck having a chuck body to which the master jaw is attached, The T-nut is a machine tool chuck characterized in that it can be moved to the very end face of the center of the master jaw by providing a C-chamfered shape on the head and the ridge line on the depth side.

4. A top jaw capable of holding a workpiece and having a recess; a T-nut having a jaw portion and capable of being fitted into the recess of the top jaw; a master jaw having a recess that can be fitted onto the T-nut; In a machine tool chuck having a chuck body to which the master jaw is attached, The T-nut is a machine tool chuck characterized in that it can be moved to the center end face of the master jaw by providing an arc-shaped R-shape on the head and the ridge line on the depth side.

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