CS239124B1 - Collet clamp for rotation tools with cylindrical shank - Google Patents

Abstract

The purpose is to facilitate the operation of the clamp by reducing the tightening force at the same time increasing the resulting clamping force to the cylindrical Shank of rotary tool and construction simplifying the clamp. This purpose is achieved by utilizing the difference the thread pitch angle of the tightening nut which is directly placed on cylindrical part of the mandrel support mandrel.

Description

increasing the resulting clamping force on the cylindrical shank of the rotary tool and design simplifying the clamp.

This is achieved by utilizing the thread pitch difference of the tightening nut that is directly supported on the cylindrical portion of the collet chuck.

259 124 (52) Int. αΛ

B23G 5/157

239 124

The invention relates to a collet chuck for rotary tools with a cylindrical shank, in particular one in which the collet is pressed or pulled by a tightening nut into the tapered bore of the chuck body.

In order to ensure the highest possible clamping force, elements with the lowest passive resistance are used in the collet chuck design. However, the vibration transmitted from the tool to the clamp during machining causes the collet to loosen due to light rotation of the clamping nut mounted on the rolling elements ensuring axial displacement. To eliminate this drawback, for example, insert springs between the tightening nut and the carrier to create axial pressure and secure the tightening nut against loosening. · This solution makes the tightening of the nut more difficult and thus reduces the maximum achievable clamping force · Securing the tightening nut against loosening by the radial pressure of the soft-metal retaining body acting in the region of engagement of the counter nut with the counter-thread or the use of a slotted nut contraction, is unwieldy and greatly extends the preparation times. The clamping ring solution eliminates the inconvenience and tediousness of securing the tightening nut against loosening, but does not address the increase in clamping force while maintaining the simplicity of the clamp design. · Low clamping force is then a major limitation on the diameter of rotary tools used behind the shank.

The above drawbacks are solved by the structure of the collet chuck according to the invention, which is characterized in that the inner diameter of the tightening nut is divided by a groove into two parts, which are formed by internal threads with different pitch angle. With its first internal thread, the tightening nut is mounted on the cylindrical portion of the collet chuck and the second internal thread connects the tightening nut to the collet swivel head.

239 124

Advantages of the collet chuck according to the invention are reflected in the possibility of using cylindrical shanks for larger diameter rotary tools. The use of a cylindrical shank results in labor and material savings in the production of rotary tools. The advantage of this solution is that

The accompanying drawings show one possible embodiment of a collet chuck according to the invention. Fig. 1 shows a longitudinal section through the collet clamp; and Fig. 2 shows a longitudinal section through a tightening nut.

The collet chuck is arranged on the support mandrel 2 together with the gripper 2. In the tapered cavity 4 of the support mandrel t there is a clamping collet 4, whose conical head 8 abuts the conical bore 2 of the cap 6. in which the intermediate ball 11 is recessed in a radial direction into the cylindrical shoulder 12 of the support mandrel 1. The cylindrical portion of the cap 6 is formed with an external thread 13 engaging the second internal thread 14 of the tightening nut parts provided with internal threads 14, 17 of different pitch angle. With its first internal thread 17, the tightening nut 15 is mounted on the cylindrical portion 18 of the support mandrel 1,

The cylindrical shank of the rotary tool (not shown) inserted into the collet 4 is clamped by rotating the tightening nut 15 «mounted by its first female thread 17 on the cylindrical portion 18 of the mandrel 1». The resulting movement of the cap 6 acts on the collet 4, which clamps the shank of the tool (not shown) with its cylindrical clamping wall. The cap head 6 may have only axial movement provided by balls 11 positioned around the circumference of the cylindrical shoulder 12 of the support mandrel 2 and engaging grooves 10 oriented parallel to the axis 9. By utilizing the pitch angle difference between the internal threads 14, 17 of the tightening nut 12 for clamping the cylindrical tool shank while maintaining the same amount of tightening force applied to the tightening nut 12s. Increasing the clamping force allows the use of cylindrical

239 124 shanks for larger diameter rotary tools. The use of cylindrical shanks reduces the labor and material demands of rotary tools and reduces the number of clamps. At the same time, the difference in pitch angle of the female threads 14, 17 secures the tightening nut 15 against spontaneous loosening during the working process. The advantage of this solution is that the clamping collet X is not subjected to severe stresses when clamping the tool.

Claims (1)

SUBJECT OF THE INVENTION 239 124 Collet chuck for rotary tools with cylindrical shank, the chuck of which is pushed into the tapered bore of the chuck body by an union head controlled by a tightening nut, characterized in that the inner diameter of the tightening nut (15) is divided into two parts by groove (16). formed by internal threads (14, 17) with different pitch angle, the tightening nut (15) with its first internal thread (17) being mounted on the cylindrical part (18) of the collet chuck (1) and in the second internal thread (14) a cap (6) is mounted.