Joints and connections – Interfitted members – Clamped members
Reexamination Certificate
1998-05-29
2001-01-30
Browne, Lynne H. (Department: 3629)
Joints and connections
Interfitted members
Clamped members
C403S374300, C403S350000, C411S432000, C411S917000, C279S140000
Reexamination Certificate
active
06179512
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a system for actuating a conventional collet, and more particularly to a collet nut for actuating any manner of collet.
The use of tool holding collets is well known and understood in the art. With conventional systems, typically a body member, such as a drive spindle, defines a collet holder having a tapered bore for receipt of a collet. Conventional devices are also known wherein the spindle has a straight or untapered bore for receipt of the collet. The collet has a frusto-conical outer circumferential surface essentially matching that of the tapered bore. A threaded nut engages a front face or portion of the collet and forces the collet axially rearward into the tapered bore as the nut is threaded onto the collet holder. With the untapered bore devices, the collet has a tapered or frustoconical forward end that engages with a matching surface in the collet nut wherein the collet is actuated primarily by compressing the front end thereof instead of being forced axially into a tapered bore. These conventional systems typically require the use of an additional wrench or other tightening mechanism to apply the final tightening torque to the collet nut. Accordingly, an engaging face is defined on the collet nut for engagement with a wrench or similar device.
The use of external tightening devices, such as wrenches, can be time consuming and burdensome, particularly where the working area of the collet nut is limited or otherwise obstructed. Also, the operator must maintain the separate tightening wrench or device in close proximity, or at least be always aware of its location. Loss of the wrench can be quite frustrating and time consuming.
The present invention relates in particular to an improved collet nut wherein the final tightening force can be manually applied without the use of a wrench or other external tightening device.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to provide an improved collet nut wherein the nut can be tightened fully without the use of an external wrench or other tightening device.
An additional object of the present invention is to provide an improved collet tool holding device incorporating a collet nut that can be fully manually tightened.
Still another object of the present invention is to provide an improved collet nut for use with any manner of conventional collet.
Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In accordance with the objects and purposes of the invention, an improved collet nut is provided for holding a collet in a chamber of a collet holder. The collet nut according to the invention is not limited to any particular type of collet and may be utilized with any collet or collet holding device or system wherein the collet is actuated by a collet nut which forces the collet into a tapered bore of a collet holder or compresses a forward end of the collet held in a straight bore. For example, the invention is particularly useful with conventional split-steel collets and Rubber-Flex® collets having individual jaw blades imbedded in a resilient material of Jacobs® Chuck Manufacturing Company used in tapered and untapered bore systems.
The collet nut according to the invention includes a nut member having a threaded inner diameter bore for engagement with threads on any conventional collet holder. As is commonly understood, the collet holder may incorporate a tapered inner diameter bore for receipt of the collet. The collet nut includes an operating member rotationally coupled to the nut member during a first tightening mode of the collet nut. In this first tightening mode, the operating member, which may include a sleeve member, is manually rotated in a tightening direction causing the nut member to threadedly advance on the collet holder. A collet engaging member is configured to engage and push a collet into the tapered chamber of the collet holder as the nut member advances on the collet holder, or to compress the collet radially inward with collet holders having untapered bores. This first tightening mode continues until a predetermined frictional load is reached between the nut member and the threads of the collet holder.
The collet nut incorporates a rotational disengaging system disposed operationally between the operating member and the nut member wherein upon reaching the predetermined frictional load between the nut member and the collet holder, the operating member rotationally disengages from the nut member as the operating member or sleeve is turned further in the tightening direction. Upon this disengagement, the collet nut enters a second tightening mode wherein a supplemental axial force generating mechanism imparts an additional axial force to the collet engaging member upon further rotation of the operating member without additional rotation of the nut member. Further rotation of the operating member imparts a rearward axial force to the operating member and collet engaging member thereby forcing the collet further into the tapered bore of the collet holder for the final manual tightening of the collet nut.
In a preferred embodiment of the invention, the rotational disengaging system comprises a resilient member, such as a click spring member, rotationally fixed to one of the operating member or the nut member and rotationally disengageable from the other of the operating member or nut member in the second tightening mode. For example, the click spring or resilient member may be rotationally fixed to the nut member and comprise resilient arms that releasably engage in recesses or slots defined in a sleeve member of the operating member. Operation of the resilient member may also be reversed wherein the resilient member is rotationally fixed to the operating member and releasably engaged with the nut member.
The operating member may comprise any combination of elements and, in a particularly preferred embodiment, the operating member comprises a sleeve member that is rotationally coupled to an annular ring member so that upon manual rotation of the sleeve member, the annular ring member also rotates.
A preferred supplemental axial force generating mechanism includes ramped surfaces defined on oppositely facing annular surfaces of the operating member and the nut member. For example, in the embodiment wherein the operating member includes the annular ring, the ramped surfaces may be defined on facing surfaces of the annular ring and the nut member. The ramped surfaces are circumferentially ramped from a low point to a high point. The ramps can have any degree of ramp depending on the particular design of the collet nut, and can be ramped through any arc of the circumference of the annular surfaces. For example, the ramped surfaces may be continuously ramped over the entire circumference of the annular surfaces, or may be ramped only through a defined arc, such as 180°, of the annular surfaces. Bearing members, such as balls, are disposed in the ramped surfaces so that the operating member and nut member rotate relative to each other in the second tightening mode.
In the first tightening mode of the collet nut, the low sections of the ramped surfaces are axially opposite from each other and the operating member and nut member are rotated together until the frictional forces between the threads of the nut member and tool holder exceed the load of the disengaging system, such as the resilient member, between the operating member and the nut member. At this point, the nut member will cease to rotate upon further manual rotation of the operating member, and such further rotation of the operating member relative to the stopped nut member will cause the high point of the ramped surface on the operating member to rotationally approach the high point of the ramped surface on the nut member. As the high points rotationally approach each other, the operating member, f
Aultman William H.
Gibson Stephen E.
Browne Lynne H.
Cottingham John R.
Nelson Mullins Riley & Scarborough LLP
Power Tool Holders Incorporated
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