US 20050260052 A1
In one embodiment, the present invention includes an apparatus including an adaptor body having a first end to be coupled to a rotary device and a second end having a tapered portion, and a tool adaptor dimensioned to fit within the tapered portion, the tool adaptor having a receiving end to receive a tool, such as a bit.
18. An apparatus comprising:
a body having a first end and a second end to be coupled to a collet for a rotary machine, the first end having an opening to receive a tool; and
a spring constrained within the body to spring lock the tool.
19. The apparatus of
20. The apparatus of
21. The apparatus of
22. An apparatus comprising:
a body having a first end and a second end to be coupled to an output shaft of a rotary machine;
a spring coupled to the first end of the body; and
a cap mounted around the spring and tensioned thereby, the cap fitted in movable relation to the body, the cap having an opening to receive a tool.
23. The apparatus of
24. The apparatus of
25. The apparatus of
26. The apparatus of
27. The apparatus of
28. The apparatus of
29. The apparatus of
35. An apparatus comprising:
a nut having a first end and a second end to be coupled to a collet shaft of a rotary machine, the first end having an opening to receive a tool; and
a spring having a first end threaded onto the nut to spring lock the tool.
36. The apparatus of
37. The apparatus of
38. The apparatus of
39. The apparatus of
This application claims priority to the U.S. Provisional Patent Application No. 60/367,642 filed on Mar. 25, 2002 in the name of Christopher Scott Lovchik and James David Jochim entitled TOOL FREE, QUICK RELEASE, SPRING ACTUATED CHUCK.
The present invention relates to an adaptor device, and more particularly to a quick-change adaptor for cutting tools.
Currently, no simple and inexpensive quick-change (QC) devices exist for swapping cutting bits in and out of standard rotary cutting machines. Machines such as routers, grinders, and small mills have the capacity to use thousands of cutting bits but unfortunately lack an easy or quick way to switch between these bits. Standard bit changing procedures typically require the user to either manipulate two individual tools or manipulate one tool while the preventing the machine shaft from rotating.
For example, routers such as CRAFTSMAN™ routers (available from Sears Co., Chicago, Ill.) use a split collet and jam nut to secure a cutting bit to a router. In such a configuration, the collet uses the bore in the router shaft for alignment. The bore is the only precision surface needed, and the outside diameter and the threads can have considerable error with little to no adverse affect on the performance of the router. However, no quick adaptor exists for such a router or other rotary machine.
Thus a need exists for an adaptor to provide for quick and easy tool changing. More so, a need exists to provide such quick tool changing that can handle errors in a machine shaft and threaded adaptor device.
Embodiments of the present invention provide a compact and inexpensive way to allow quick and easy tool changing. Such devices can be readily actuated with one hand and requires no additional tooling or procedures (for either tool insertion or release). In certain embodiments, a device may be used in automated bit changers in certain machines. The small size of the device allows it to be used with small hand grinders or woodworking routers without significantly increasing the effective machine spindle length. As such, most existing tools can be retrofitted with this device without affecting their performance. Certain embodiments of the device may also incorporate several safety features that protect against inadvertent release of a spinning bit.
In forming the QC assembly, the QC body adaptor nut retaining ring (3) may be inserted into a retaining ring groove (19) on the quick-change body (1), and the quick-change body adaptor nut (2) may be slipped down onto the body (1) and snapped over the ring (3). In this embodiment an internal groove (20) (shown in
In further formation of the assembly, the locking balls (5) may be inserted into holes (21) on the QC body (1) and two force compensation half rings (4) may be inserted into a groove (22) (also shown in
Any number of bit adaptor assemblies can be constructed using either a collet system or a setscrew system as shown in
Referring now to
Referring now to
In certain embodiments, the exterior taper on the bit adaptor body (11) may match the interior taper of the quick-change body (1) to insure accurate axial bit alignment. The heads of the bit adaptor torque pins (13) may protrude and be constrained by grooves or sculpted slots (27) on the QC body (1). These sculpted slots (27) may allow the machine spindle torque to be transferred through the QC body (1) to the torque pins and finally to the spinning bit. More so, sculpted slots (27) permit a bit adaptor assembly (10) to be inserted in any angular position, as the slots (27) will guide bit adaptor assembly (10) to the proper seating. As such the bit adaptor assembly (10) can be inserted blind and it will still be properly engaged in adaptor body (1). In various embodiments, simply lifting up on the actuating collar (7) may release the bit adaptor assembly (10).
In certain embodiments, the cam slot (23) may provide several safety features. Such features may include an inertial lock, an anti-ball jam lock, as well as audible and visual indication of correct bit insertion. The inertial lock may utilize the rotational motion of the actuating collar (7) dictated by the control (i.e., cam) slot (23) in the actuating collar (7) and cam pin (8) attached to the QC body (1). If the actuating collar is pulled up, as if to release the bit assembly, it is forced to rotate opposite the running direction of the machine spindle. As the machine is spun up, the actuating collar (7) lags the QC body (1) because of its rotational inertia. This lag forces the cam pin (8) to travel down the cam slot (23), which pushes the actuating collar (7) further down, which adds to the inward force of the locking balls (5) that holds the bit adaptor assembly (10) in place. The crescent shape of the cam slot (23) maximizes the inertial force by providing and increasing force angle as the actuating collar (7) rotates. The geometry of the cam slot (23) may also ease actuation of the actuating collar (7) by reducing the force angle when the actuating collar (7) is depressed.
Full rotation of the actuating collar (7), as dictated by the cam slot (23), may be required in order to insert or remove a bit adaptor assembly (10) in certain embodiments. Internal ball relief grooves (28) (see
Referring again to
In certain embodiments, a bit adaptor assembly (10) is installed by simply pushing it into quick-change body (1). The bit adaptor torque pins (13) engage the tapered surfaces (29) on the actuating collar (7), forcing it to rotate in the running direction of the router. Once the collar (7) is rotated out of the control slot detent (30), the actuation spring (6) takes over and it snaps the actuating collar (7) down, grabbing the bit adaptor assembly (10). The snap of the actuating collar (7) provides an audible indication that the bit adaptor assembly (10) has been properly seated. Due to the rotation of the actuating collar (7), a further visual indication may be given when marks on the QC body (1) and on the actuating collar (7) are in alignment. If these marks do not line up, then the bit adaptor assembly (10) has not been properly installed.
The force-compensating half rings (4) provide another safety feature in certain embodiments. During operation the half rings (4) are thrown outward by centrifugal acceleration against a tapered surface (31) (shown in
The centrifugal force referred to earlier may produce a proportional frictional force between the half rings (4) and the actuating collar (7), which may oppose any motion in the collar (7), either up or down, that might result in bit assembly (10) release. The more massive the half rings (4) become the more frictional force that they are able to generate at any given rotational speed. More so, while described as half rings, it is to be understood that force compensation rings need not be fully semicircular and in certain embodiments, more than two such ring portions may be present.
Quick-change devices in accordance with embodiments of the present invention may be adapted to tools that do not have a removable collet as well as tools that have just a simple shaft. This is done by colleting to the shaft as shown in
As discussed above, in various embodiments a quick-change assembly may be dimensioned to not significantly increase the effective machine spindle length. In certain embodiments, an assembly may vary depending on the machine in which it will be used. Further, while tool sizes may vary, in certain embodiments the quick-change assembly may accommodate tools having shanks up to ½″ inch.
As discussed above, certain routers use a split collet and jam nut to secure a bit. Referring now to
The embodiment of
Though many routers are within expectable ranges for such a quick-change design, other routers have both radial errors (concentricity) and axial errors (angular run out) that may exceed the capabilities of the embodiment of
To prevent such deformation, the embodiment of
In other embodiments, a spring-based quick-change adaptor may be used.
In the embodiment of
This device works by utilizing the tension in the spring to hold the bit tight (and ground the input torque) when the machine output shaft rotates in the clockwise direction (cutting direction). In addition, the tension in the spring also serves to close or clamp the split collet around the bit, also grounding the torque. The phenomenon being utilized is described by the equation Tout=Tin/e(βν), where Tin is the tension at one end of the spring, β is the total angle through which the spring wire is wound, ν is the coefficient of friction between the spring and the surface that it is wound about, and Tout is the tension at the opposite end of the spring. The locking spring is sized by setting Tin to the maximum torque applied to the bit divided by the bit shaft radius. Tout is set to the tension created by stretching the wire around the bit or collet. The equation is then solved for the total wrap angle (β). This is the number of wraps of the spring needed to assure that the spring will not slip on the shaft. The same calculation is done to determine the number of locking spring wraps needed to ground the torque to the split-collet. It is important to note that this phenomenon acts only in only one direction (which is determined by the direction of spring wrap) and is the major reason that bit insertion and removal is so easy.
In certain embodiments, the insertion and removal of bits can be made even easier by the addition of the mechanism shown in
Referring now to
The embodiment shown in
This spring-lock phenomenon can also be used as a one-way shaft clamp or torque coupler configured as in
The shaft clamp embodiment shown in
Embodiments of the present invention may incorporate a variety of interfaces for shaft attachment including a hollow shaft with the spring wound into it coupled to the outside diameter of a second shaft. Embodiments may also be made to lock in either rotational direction by varying the spring direction.
Devices in accordance with embodiments of the present invention may be designed using any number of actuating spring configurations. Such devices may incorporate a variety of interfaces for shaft attachment. Such devices may employ any number of different positive locking mechanisms, both passive and/or active. Such devices may use other geometries for torque grounding, bit alignment, and bit capture. The configuration may be altered to adapt to any number of rotary machines of all makes and models. The locking balls may be replaced by pins or wire forms that run in straight, angled, or other slot geometries.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.