Cutters – for shaping – Rotary cutting tool – Including holder having seat for inserted tool
Reexamination Certificate
2001-02-14
2001-12-04
Tsai, Henry (Department: 3722)
Cutters, for shaping
Rotary cutting tool
Including holder having seat for inserted tool
C407S038000, C407S043000, C407S046000
Reexamination Certificate
active
06325574
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to saws and machining slot cutters in which each tooth is mounted in the body of the saw or cutter in a removable cartridge for individual maintenance and replacement of the teeth.
2. Description of Prior Art
Saws and machining slot cutters for commercial and industrial usage sometimes have individually removable tooth cartridges mounted on the periphery of the saw or cutter body. Each cartridge holds one tooth. This allows replacement of teeth without replacement of the cutter body, and makes maintenance of the teeth easier. One disadvantage is the possibility that the cartridge may loosen during operation—an unsafe condition. A second disadvantage is that the cartridge and its mounting mechanism takes space, reducing the maximum number of teeth on the cutter in comparison to non-removable teeth. A third disadvantage is cost, since individual teeth, cartridges, and their associated mounting hardware greatly increase the complexity and number of parts in a cutter in comparison to non-removable teeth. A fourth disadvantage is the effort and skill required to install the cartridges properly in the cutter. Thus, what is needed is a removable cartridge mechanism with minimal size and complexity that is highly secure and easy to install properly. The present invention fills this need.
The following U.S. patents show earlier related inventions:
U.S. Pat. No. 4,257,302 (Heimbrand 1981)
U.S. Pat. No. 424,263 (Bole 1890)
U.S. Pat. No. 221,602 (Ohlen 1879)
U.S. Pat. No. 205,042 (Brooke 1878)
U.S. Pat. No. 146,680 (Husbands, Jr. 1874)
U.S. Pat. No. 141,427 (Crookes 1873)
U.S. Pat. No. 103,045 (Hiles 1870)
U.S. Pat. No. 31,073 (Brown 1861)
For example, Heimbrand provides a cartridge mounted in an open-ended slot that converges toward the open end. The user must insert a cam between the cartridge and the cutter body, hold the cartridge in position, slide a tooth between the cartridge and cutter body opposite the cam, and hold the tooth and cartridge in position while locking the cam. This requires a high degree of manual dexterity. It also requires manual strength, since a cam provides less than 360 degrees of rotation between its loose and tight conditions, and thus cannot provide the high mechanical advantage of a screw. In Heimbrand, if the cam is not fully tightened, or works loose during operation, the tooth can fly out, releasing the cartridge as well.
SUMMARY OF THE INVENTION
An objective of the present invention is a removable tooth cartridge of minimal size in order to maximize the number of teeth on a cutter. A further objective is maximal locking force holding the cartridge in the cutter body. A further objective is safety and stability of the cartridge in the cutter. A further objective is ease, speed, and consistency of positioning and installing the cartridge in the cutter body, and ease and speed of removing the cartridge from the body. Further objectives include minimizing the number of parts and maximizing the practicality and simplicity of production of cutters according to the invention.
These objectives are achieved with a cartridge just large enough to hold a tooth and a setscrew. The cartridge has an open-sided tap for the setscrew that exposes a side of the setscrew. The cutter body has a slot to receive the cartridge. The slot has a leading side with a generally cylindrical smooth concave portion that surrounds the exposed part of the setscrew. The cylindrical concave portion is uniquely angled to wedge the setscrew firmly against the cylindrical concave portion as the setscrew is tightened, and to force the cartridge against the bottom and trailing side of the slot. The cartridge and slot preferably have interlocking interfaces on both their leading and trailing sides. These interfaces are preferably parallel and slidable, allowing the cartridge to slide into the slot while engaging both the leading and trailing interlocks. This allows setscrew to easily be manually tightened with strong force while the interlocks hold the cartridge steady. With the setscrew tightened, the cartridge is firmly forced against the bottom and trailing sides of the slot. The cartridge cannot slip out of the slot even if the setscrew is loose, because the setscrew is blocked by the cylindrical concave portion of the leading side of the slot. Thus secondary retention is provided in the event of a loose setscrew.
REFERENCES:
patent: 31073 (1861-01-01), Brown
patent: 103045 (1870-05-01), Hiles
patent: 141427 (1873-08-01), Crookes
patent: 146680 (1874-01-01), Husbands, Jr.
patent: 205042 (1878-06-01), Brooke
patent: 221602 (1879-11-01), Ohlen
patent: 424263 (1890-03-01), Bole
patent: 657873 (1900-09-01), Jewett
patent: 1700333 (1929-01-01), Pond
patent: 2309657 (1943-02-01), Miller
patent: 3163920 (1965-01-01), Stier
patent: 3584361 (1971-06-01), Erkfritz
patent: 3798724 (1974-03-01), Czopor
patent: 4078868 (1978-03-01), Erkfritz
patent: 4257302 (1981-03-01), Heimbrand
patent: 6056484 (2000-05-01), Mitchell et al.
1 Page drawing and description of Type I prior art provided by Applicant.
1 Page drawing and description of Typ 2 prior art provided by Applicant.
Stewart John V.
Tsai Henry
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