Gear cutting – milling – or planing – Milling – Work support
Reexamination Certificate
1998-08-04
2001-12-11
Hughes, S. Thomas (Department: 3726)
Gear cutting, milling, or planing
Milling
Work support
C409S197000, C409S219000, C269S021000
Reexamination Certificate
active
06328507
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cutting machine tool such as for wood working and iron working and, in particular, to a working table apparatus for the cutting machine tool for positioning and securing a work or works thereon.
2. Description of Background Art
In general, with cutting machine tools such as a milling machine or router for wood working, the mounting and removal of a work on the working table of the machine tool has been carried out using clamping members and bolts adapted to be fastened and loosened by a spanner in a well-known manner. More recently, it has been proposed to clamp the wood on a jig secured on the working table using fluidic or electromagnetic force.
Although the conventional clamping apparatus using the clamping members and bolts is easy to manufacture, it is inferior in clamping efficiency and thus its use is limited to single or small-quantity production applications. On the other hand, the automatic or semi-automatic clamping arrangement using the jig, while superior in clamping efficiency, is costly to manufacture and requires substantial time for mounting the jig.
In order to overcome the problems mentioned above, in recent years there has been developed a clamping method in which the work is clamped on a top plate covering the top surface of the working table by negative pressure supplied through suction ports formed in the top plate from a negative pressure chamber formed in the under surface of the top plate (see, for example, Japanese Utility Model Registration Gazette No. 2503256).
However, in high volume production applications, positioning efficiency suffers if the machining specification and the sliding direction of the working table have to be set each time the works are fed onto the working table. Accordingly, it is known to eliminate the positioning adjustment by initially adjusting the position of one or more locating pins or locating blocks on the working table and then positioning the work or works by abutting the reference surface of the work against the locating pins or blocks.
Although the method using locating pins or blocks makes the mounting and removal operation remarkably easy, it also suffers the serious disadvantage that the locating pins or blocks often interfere with tools mounted on the spindles of the machine tool causing damage to either the locating pins or blocks or to the tools.
In addition, the locating pins or blocks must be exchanged whenever works of different sizes are to be machined.
Furthermore, operation of the machine tool must be stopped for a long period of time to mount, adjust, and/or remove a large number of pins or blocks when the works to be machined are small in size or great in number.
In addition, when works are positioned by abutting them against the locating pins or blocks, a positioning error frequently occurs as a result of imperfect contact between the work and the locating pins or blocks.
Moreover, when using negative pressure or electromagnetic force to clamp works onto the working table, the required operating buttons or actuating elements are usually mounted on the bed of the machine tool. Consequently, the distance between the working table and the actuating elements is increased whenever the working table is moved to its extreme positions thus making the clamping operation difficult.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a working table apparatus for a cutting machine tool which overcomes the problems of the prior art mentioned above.
According to the present invention, it is possible to position a work or works on the working table by contacting the sides of the works against positioning members which are selectively projectable from the work supporting surface. No obstacle exists on the working table when the positioning members are retracted therefrom and thus interference between the positioning members and the tools is completely eliminated. The projection and retraction of the positioning members is carried out by fluidic pressure or electromagnetic force.
Further in accordance with the present invention, positioning members are arranged in a row either in a direction parallel with the sliding direction of the working table or in a direction perpendicular thereto. When abutting the reference side of the work against the row of the positioning members, the reference side extends parallel with the moving direction of the working table or perpendicular thereto. The mounted attitude (direction) of the work is thus determined and therefore it is possible to easily drill apertures or to cut a groove parallel with one side of the work.
Since the present invention employs a plurality of positioning members which can be simultaneously projected or retracted, it is possible to project and retract multiple positioning members much more quickly than the time required to separately locate individual positioning members.
Additionally, the positioning members may comprise a first group of positioning members arranged in a row either in a direction parallel with the sliding direction of the working table or in a direction perpendicular thereto and including at least one second positioning member arranged offset from each row. Thus one pair of the first and second positioning members has a substantially L-shaped configuration in its plan view formed by a long side and a short side (or one point).
Accordingly, the work can be positioned by sliding the work on the work supporting surface and abutting its reference side against the positioning members once they are projected from the work supporting surface.
When the reference side of the work is abutted against the first positioning members, the sides of the work assume positions parallel with the edges of the working table. Upon further sliding of the work on the supporting surface and abutting the other side against the second positioning members, the position of the work can be finally determined and thus the work can be clamped at its accurate position.
According to a further aspect of the present invention, since a plurality of groups of positioning members may be formed on the working table, a plurality of works can be simultaneously positioned and worked.
That is, any size or any number of work pieces can be mounted on the working table by using any suitable positioning members in any group of the positioning members.
According to a further feature of the present inventions, it is possible to selectively hold the positioning members in their retracted positions.
This makes it possible to mount a large work on the working table by selectively projecting only the positioning members arranged along the edges of the working table.
According to a further aspect of the present inventions, the actuating elements for the holding means are positioned near the working table (i.e., near an operator regardless of the movement of the working table), enabling easy operation of the actuating elements.
Most preferably, the actuating elements are arranged on the front side of the working table so that the operator can access the actuating elements from either lateral sides of the working table.
The present invention further enables the position and the attitude of the work to be easily determined by abutting the sides of the work against the positioning members, thus enhancing high productivity.
Additionally, the present invention enables the work to be secured on the working table by a negative pressure (i.e., a pressure lower than the atmospheric pressure) acting on the under surface of the work.
After the completion of clamping of the work, the positioning members are retracted below the work supporting surface by the fluidic pressure of the electromagnetic force and thus the interference of the positioning members with the tools during the cutting or other machining operation is avoided.
Finally, the present invention enables the operator to confirm completion of positioning of the work without visual confirmation. This makes the mounting of t
Harness & Dickey & Pierce P.L.C.
Hughes S. Thomas
Omgba Essama
Shoda Iron Works Co., LTD
LandOfFree
Working table apparatus for a cutting machine tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Working table apparatus for a cutting machine tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Working table apparatus for a cutting machine tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2560948