Patent Application
20130202374
The prior art below relates primarily to jig boring tools, as they are commonly known in the machining art.
The term “jig”, when used in tooling, has many meanings, ranging from a simple plate used as a template, such as for hole locations, to very large, complex machines primarily used for boring holes in often very large pieces of material. However, the term “jig boring” often means complex machinery for extremely accurate hole drilling and/or finishing, such as smoothing, or precise hole sizing. Such uses normally require both “in line” boring, such as precision drilling in a material, and “facing” operations, often known by other names, such as “radial” boring, which involves smoothing or adjusting cuts with a tool bit inserted within a material.
As defined in the free internet dictionary, Wikipedia, on Aug. 27, 2010:
“The jig borer is a type of machine tool invented at the end of World War Ito make possible the quick-yet-very-precise location of hole centers. It was invented independently in the United States and Switzerland. It can be viewed as a specialized species of boring mill or milling machine that provided tool and die makers with a higher degree of positioning precision (repeatability) and accuracy than those general machines had previously provided.”
In jig boring, a boring bit for precisely cutting material, such as metal, is disposed with a radial holder for cutting inside a hole, such as a large hole which is not amenable to drilling operations.
It is often desired that very small adjustments be made to a tooling bit position, such that very fine increases in the cut depth in a material may be made. This is often desired for many reasons, with three given below:
1. for providing a smooth surface, such as with a very fine smoothing cut,
2. for using high speed steel instead of more expensive cutters, such as carbide bits, to decrease the cost. The use of high speed steel requires that the cut depth be carefully controlled, as otherwise the bit may be damaged by the resulting pressure from a deeper cut which may be exerted on the bit.
3. Making very small cuts, such as to finish a part which is found to require a small amount of extra cutting, similar to a smoothing cut, but for a different reason; to adjust the size of the cut.
Wikipedia further tells us:
“Before the jig borer was developed, hole center location had been accomplished either with layout (either quickly-but-imprecisely or painstakingly-and-precisely) or with drill jigs (themselves made with painstaking-and-precise layout). The jig borer was invented to expedite the making of drill jigs, but it helped to eliminate the need for drill jigs entirely by making quick precision directly available for the parts that the jigs would have been created for. The revolutionary underlying principle was that advances in machine tool control that expedited the making of jigs were fundamentally a way to expedite the cutting process itself, for which the jig was just a means to an end. Thus the jig borer's development helped advance machine tool technology toward later NC and CNC development. The jig borer was a logical extension of manual machine tool technology that began to incorporate some then-novel concepts that would become routine with NC and CNC control, such as:
Franklin D. Jones, in his textbook Machine Shop Training Course (5th ed), recorded insightfully:
“In many cases, a jig borer is a ‘jig eliminator.’ In other words, such a machine may be used instead of a jig either when the quantity of work is not large enough to warrant making a jig or when there is insufficient time for jig making.””
Further research shows the following regarding jig boring:
“The lateral movement of the boring head and the movement of the table are controlled by lead-screws, set by micrometer drums. A pitch-correction device rotates the vernier sector, by which the setting of the micrometer drum is made, by an amount which eliminates the error at the position in which the table or head is being set. The amount of rotation is determined by a lever, in the ratio of 200:1, in contact with a metal template. The template was made for each lead-screw in terms of a high precision scale read with a microscope at one centimetre intervals.”
Often the complicated and expensive arrangement described above is not required. An operator may need to measure a dimension, then adjust the bit by a very small amount, but without the need or desire for a micrometer adjustment such as with a vernier instrument. This is especially true of less developed or developing nations, where the technology does not exist to develop state of the art machines, and the financial ability to buy such machines cannot be found.
U.S. Pat. No. 8,092,124 teaches a facing mill head with screw-adjustable holders in keyed slots. The slots are in a mill head shaped much like a collar; in that it radially extends beyond an abutting boring bar. The '124 patent includes a locking screw, something like a set screw. The locking screw of the '124 patent forms a firm connection to the above head by distorting the holder, which has slots axial to the holder provided to allow such distortion. While the '124 patent discloses many desirable and long-needed features, distorting the holder, and the need for a through screw for such distortion, precludes many bits, such as “bar” bits of a hard material, while such distortion may cause bit misalignment. Further, the '124 patent, which uses a conical head screw for adjustment, allows a very narrow range of adjustment of the holder, much less than is often desired, and changing a bit requires dismounting the holder because removing the screw removes the holder. Further, the '124 patent teaches a dead-end head for holder mounting, and cannot be positioned at an arbitrary point along a boring bar. The '124 patent also teaches a holder and slot for said holder that require special care in machining and general preparation; a simpler, less expensive bit holder and device for positioning the holder is needed. Even so, the '124 patent is a significant improvement over the art before it. More needs to be done, though, since it is often desirable to, for example, position a bit along, for example, a boring bar (less important with a milling head, as in the '124 patent), or to improve the range of adjustment (less important with a milling head). Cost and simplicity, such as for maintenance, is also of great importance, especially when, as with a boring tool, a bit is not always visible, but may be positioned within a part being machined.
U.S. Pat. No. 2,654,610 teaches a jig boring head for adjusting a bit position relative to a material being machined in a jig boring machine. The '610 patent includes a vernier adjustment for making small increments in a position of a bit or similar cutting tool, but does not anticipate using a simpler, less costly, and often sturdier, therefore longer lasting, apparatus for the same purpose.
U.S. Pat. No. 3,067,636 teaches a jig boring head for cutting tool positioning in a jig boring machine, and similarly does not anticipate the use of a low-cost, simple, and sturdy apparatus for the same purpose.
U.S. Pat. No. 3,069,932 teaches an apparatus for using a head for a cutting tool in a jig boring machine by radial changes of an orientation of said tool with an offset lead screw. While the '932 patent shows achieving a fine adjustment with a lead screw, and is therefore simpler than using vernier adjustment, the adjustment apparatus of the '932 patent is non-linear and causes a change in the relative positioning of the cutting tool with respect to the material being cut. These factors are only a few of the disadvantages of the '932 patent, which teaches a machine that is somewhat complex and costly to implement.
U.S. Pat. No. 3,144,792 teaches fine adjustment of a cutting tool in a jig boring head or similar apparatus, by means of a relatively coarse adjustment, such as with a lead screw, as is known in the art, and a finer adjustment by means of a vernier apparatus. With two interacting adjustment means, the teaching of the '792 patent is more complex and more costly than the present invention.
U.S. Pat. No. 3,144,792 teaches fine adjustment of a cutting tool in a jig boring apparatus with a micrometer adjustment, and including an anti-backlash improvement for boring eccentric to a turning axis. The '792 patent, while providing for less distortion, such as with vibration or other disturbance, is more complex and more costly than the present invention.
U.S. Pat. No. 3,647,307 relates only to a boring bar, and while it does hold a tool bit for cutting, such as in jig boring, is not directly relevant to the jig boring apparatus of the present invention.
There is a long felt, unsatisfied need for a simple, low cost, sturdy jig boring apparatus or head for making incremental adjustments to tools used for cutting and shaping materials, such as jig borers. There is also a long felt unmet need for a jig boring head that is adapted solely for radial boring to eliminate the need for costly and complex mechanisms for performing this function.
Tooling, such as jig boring tools, in the United States are generally complex, since they are usually intended to minimize physical labor, with relatively little thought to the cost of the tooling. In other countries, such as P. R. China, the opposite may be true. Labor may be low in cost, and the cost of tooling, especially high wear, relatively short life time tooling such as jig boring tools, may be much more of a concern.
As a result, there is a great need for very simple, low cost tooling, yet the thinking resulting in such simple tooling may be as complex or even more complex than for more complex tooling, since the simplest solution is often the least obvious. As Einstein once said, “An intelligent man can solve even the most complex problem; a genius makes the problem simple”.
However, it is well understood in many parts of the world, or even generally, that one does not pay for something one is not legally obligated to pay for. Therefore, an inventor who teaches a simple, yet powerful tooling approach, if the approach is unique, must obtain legal protection, or there will be little or no incentive for developing such tooling.
In the case of tooling used for products to be used in the United States of America, this means a US patent for such an invention; since legal protection for an invention may be non-existent outside the US. This presents a problem for an inventor: technology that might be considered trivial (even though recognized as very inventive) in the US, is still of great value for an inventor serving the needs of American companies overseas, for example, in P. R. China.
Fortunately the US Patent Law recognizes the value of simplicity in an invention, so such protection may be available. Without it, both American and overseas companies would suffer.
The invention described herein is simple, and therefore low in cost, but extremely inventive, as will be shown in the following disclosure.
A collar of a rigid material, such as steel, is placed around a spindle on a jig boring machine, as these terms are known in the art, and securely fastened in place. A tool holder, rigidly constrained by keying slots in all directions, except for motion radially outward or inward with respect to said spindle. is integral to said collar, and a tool bit is inserted and secured in said tool holder. Said tool holder and interface within said collar secures a screw for advancing and/or retarding said tool holder, and thereby said bit, with respect to said collar and said spindle to which said collar is secured. It is important to understand that said collar, unlike most tooling solutions, may be positioned at an arbitrary point along a spindle of a machine, rather than only at an end of said spindle, since said collar may be mounted on a machine with limited ability for positioning said spindle with respect to a work piece.
Said collar, including said tool holder, are of a rugged construction, which serves to minimize deflections and vibrations of said bit with respect to said spindle to allow precision work to be done.
Said collar being of a substantial construction, provides an inertial moment, similar to a gyroscopic action, for further reducing vibrations and deflections due to forces created by tooling cuts.
Said tool holder captures a bit, in a preferred embodiment, by encircling said bit, though other means of securing said bit are anticipated hereby, and includes means for securely holding said bit in place, such as with set screws. Said bit is easily exchanged when desired, while said tool holder holds said bit securely in place during operations such as in jig boring.
It will be appreciated that the simplified jig boring head of this invention is configured for radial boring, and provides a jig boring head with maximal ruggedness and long life, as well as relative freedom from vibration or similar error-producing aberrations, all with minimal expense and minimal complexity in making said jig boring head.
