Milling and turning machines are both machine tools used to machine, or shape, solid materials. Milling machines and turning machines are often classed in three basic forms: horizontal, vertical and lathe. These machines range in size from small-bench mounted devices to room-size machines. Milling machines and turning machines both move the work piece radially against the rotating milling cutter. Work piece and cutter movement are precisely controlled to less than 0.001 inches (0.025 millimeters). Both milling machines and turning machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC). Both machines can perform a vast number of operations, from simple (diameters, threads, grooves, slot and key weight cutting, planing, drilling) to complex (contouring and diesinking). The purpose of both CNC milling machines and turning machines is to use a set of input specifications describing a physical object to produce a machine part according to the specifications. The part is typically formed from solid block stock material such as metal, and shaped by various machine tools such as drills, mills, lathes, electrostatic discharge machines and gauging systems.
Typical CNC milling machines and turning machines have a machine spindle head with a rotating spindle shaft that handles a plurality of machining tools, including drills, mills and various styles of chip-removing cutters. When a CNC milling machine includes a mechanism for the exchanging of these tools, it is generally referred to as a machining center or CNC machining center. Milling machines, turning machines and machining centers are designed to produce a finished work piece from the raw starting material quickly and precisely. During the actual machining operations, the computer-controlled movements of the milling tools through the work piece are optimized for removing waste material from the work piece. When an exchange of tools is required, the interruption of the machining operation for the tool exchange function is typically so short that little time is added to that of actual machining.
CNC (computer numerical control) machining centers perform the cutting functions that were traditionally performed by manual milling machines. CNC equipment provides increased control and repeatability of the cutting tool. There are three basic machining centers—vertical, horizontal and lathe. The terms horizontal, vertical and lathe refer to the spindle designs of the machining center, which are in the horizontal, vertical or turning center position. A vertical machining center spindle holds the cutting tool in the vertical position and is programmed to cut in three axes—X, Y and Z. Certain of these centers will have an indexer, which can rotate the part being cut along the axis, creating a fourth axis. The vertical machining center spindle holds the cutting tool in a horizontal position and can be programmed to rotate 360° in a circular motion (the B-axis). This machining center therefore positions and cuts in four axes (X, Y, Z and B). The most advanced CNC milling machines, multi-axis machines, add two more axes in addition to the X, Y and Z axes. The B axis, as noted above, controls the tilt of the tool itself. Horizontal milling machines also have a C axis allowing the horizontally-mounted work piece to be rotated, essentially allowing asymmetric and eccentric turning. When all of these axes are used in conjunction with each other, extremely complicated geometries can be made with relative ease with this machine. In a turning center, the spindle holds the part to be machined and the turret holds the cutting tools in the horizontal position, and the center is programmed to cut in two axes—X and Z.
The accessories and cutting tools used on machine tools (including milling machines and turning machines) are referred to in aggregate by the mass noun “tooling.” There is a high degree of standardization of the tooling used with CNC milling machines, turning machines and milling centers.
The toolholder, which is assembled off line, is loaded into the machining center's tool magazine for storage. The purpose of the toolholder is to grip and center the tool. CAT tooling, sometimes called V-flange tooling, is the most common type of tooling in the United States. CAT tooling, invented by Caterpillar Inc. to standardize the tooling used on its machinery, comes in a range of sizes designated as CAT-30, CAT-40, CAT-50 etc. The numbers refer to the Association for Manufacturing Technology (formerly the National Machine Tool Builders Association or “NMTB”) taper size of the tool.
An improvement on CAT tooling is BT tooling, which has a similar appearance and can be easily confused with CAT tooling. Like CAT tooling, BT tooling comes in a range of sizes and uses the same Association for Manufacturing Technology body taper. BT tooling differs from CAT tooling in that it is symmetrical about the spindle axis, while CAT tooling is not. This gives BT tooling greater stability and balance at high speeds. SK and HSK tooling (hollow shank tooling) are more common in Europe.
CNC machines and turning machines use toolholders that have been precisely ground with a male taper that mates with the machine's specific female taper. The tool holder is secured in place with a retention knob or drawbar thread. On CNC machines, the retention knob is more popular because it allows for easier automatic tool changing.
The most common toolholder designs are the mill end holder and the collet holder. In a collet holder, the collet grips and centers the tool in the tool holder. Collets are often partially slit on the surface, allowing them to flex diametrically when clamping. Collets are available in two basic forms: double angle and single angle.
CNC toolholders, such as collet holders, have a retention knob, a taper shank, the V-flange, the key slots and the gauge line diameter. Collet toolholders also generally have a through hole that allows coolant to reach the cutting edge. The V-flange allows the automatic tool change arm to unload and load the toolholder quickly. The shank size depends on the size of the CNC machine spindle and the cutting tools. As shown in the Drawings, FIG. 1, which depicts a V-flange tool holder 1 with a taper shank 2, the retention knob 3 is inserted in the shank. The body of the shank has a coolant through-hole 4 and a gage line diameter 5. There are two key slots 6 at the base of the shank. The tool holder 1 secures the tool 7 which is held in place by a clamp nut 8.
Wrenches are the typical tools used in securing the toolholder in the machining center and securing the tool in the toolholder. The collet itself grips the tool and holds it in place inside of the toolholder. ER wrenches are used to tighten or loosen the collet (or clamp) nuts. Collet nuts may be hexagonal in shape or slotted. The disclosed ER wrench will fit both types of nuts. The retention knob (or pull stud), which is inserted in the back of the tool holder via a screw mechanism, holds the tool in the machine. The knob will be removed and reattached when tools are changed in the machine. One of the openings on the disclosed ER wrench is to tighten or loosen the retention knob (or pull stud).
A wrench is a tool that provides grip and mechanical advantage in applying torque to turn objects, such as nuts and bolts. Types of wrenches are open-end wrenches and box-ended wrenches. Open-end wrenches are one-piece wrenches with an opening that grips two or more faces of the bolt or nut. In the most common type, U-shaped wrenches, the ends are generally oriented at an angle of approximately 15 degrees to the longitudinal axis of the handle. Box-ended wrenches are one-piece wrenches with enclosed openings that grip the faces of the bolt or nut. The opening in the wrench is generally a six- or twelve-point opening that fits nuts or bolt heads with a hexagonal shape. Eight-point wrenches are also made for square-shaped nuts and bolt heads. A combination wrench is a double-ended tool with one end open like an open-end wrench and the other end enclosed like a box-end wrench.
In the machine tool industry, there are wrenches used to tighten and loosen the nuts used in securing the collet known as collet nut wrenches. Typically, a separate wrench is needed for each size of machine tool. Typical sizes in the industry are ER-8, ER-11, ER-16, ER-20, ER-25, ER-32 and ER-40. In addition, different wrenches are required for collet nuts that have slots and ones that do not (which require hexagonal wrenches). The design of prior art wrenches does not permit using the same wrench with slotted and hexagonal collets, even if they have the same taper size. Further, a separate tool is required to tighten the retention knob. Thus, numerous tools are required in changing the tool holders and tools in a typical CNC machining center.
Further, existing collet nut wrenches, which have four prongs, suffer from various infirmities. The four-point contact tends to result in uneven torque being applied to the sides of the collet and/or collet nut, causing a distortion of the collect nut and possible damage. Further, as noted above, separate four-point wrenches are needed for slotted and hexagonal collet nuts. Further, current wrenches will come loose from the collet and/or collet nut if not supported by, for example, the operator's hand. The invention disclosed below is intended to improve upon current wrenches existing in the prior art.