Gear cutting – milling – or planing – Milling – Including means to infeed rotary cutter toward work
Patent
1980-09-08
1982-12-28
Briggs, William R.
Gear cutting, milling, or planing
Milling
Including means to infeed rotary cutter toward work
408115R, 408709, 409216, B23C 305
Patent
active
043659179
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a shaft or rod guide for a tool holder, for example for a drilling or boring machine or an adjusting device, which enables working pieces to be machined with precision, in particular a shaft or rod for a tool holder for cleaning valve seats.
DESCRIPTION OF THE PRIOR ART
Conventional rods or shaft guides comprise either a fixed casing or an oscillating casing locked by mechanical means, such as the rod disclosed in French Pat. No. 562 738 filed by MONPAIN on 27th of February 1923. Such means have the disadvantage that positioning has to be carried out by trial and error which is not precise enough.
British Pat. No. 926 072 discloses a rod which oscillates by means of a spherical head capable of moving between a fixed seat and a movable seat supported by a piston acted upon by a hydraulic fluid. In this device the sole purpose of the fluid is to stop the spherical head between the two seats.
In short, these devices are operated manually and must overcome the inertia of the rod assembly. In devices of the kind described above, the rod, its casing and its means for transmission and control can attain weights of 140 kg which renders precise manual positioning impossible on account of friction.
The object of the present invention is to substantially eliminate excessive friction so as to position the rod with very great precision irrespective of the plane in which the assembly is located, and at a pressure of at least 1 g/cm.sup.2.
SUMMARY OF THE INVENTION
To achieve the object of the invention there is provided an adjustable shaft or rod guide having a casing comprising a spherical shell disposed between a movable seat and a fixed seat, the shell being alternately immobilised by pressure on the movable seat which is subjected to a gaseous fluid circuit, or is relieved of this pressure by reversal of the circuit and raised by a further gaseous fluid circuit. The shell is disposed on a cushion of gas and is enveloped thereby. The gas can escape through escape channels between the shell and the seat. In this manner the rod does not have any inertia and can assume any desired angular position.
BRIEF DESCRIPTION OF THE DRAWINGS
Other details and advantages of the invention will be apparent from the description and the claims which follow, and from the drawings in which
FIG. 1 is a schematic representation of an adjustable rod guide in accordance with the invention set up for a device for cleaning valve seats,
FIG. 2 is a section of an adjustable rod guide in accordance with the invention in an immobilised position, and
FIG. 3 shows an adjustable rod guide in accordance with the invention during the time it floats between the two seats.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 a rod 1 is provided with a holder 1a having attached thereto a tool 1b which is capable of assuming any convenient position for a guide stem 1c. The stem is an extension of the tool and can be introduced into a guide GS of a valve of a motor M having a valve seat SP to be cleaned. In a classical manner the support head for the rod (here housing 3) is subjected to alternate displacements in a horizontal plane according to arrrows f1 and f2. A table T is integral with the housing 3.
The displacements may be mechanical, hydraulic or pneumatic and serve the purpose of moving the centre 0 of the rod so as to align its axis X--X with the extension of the axis of the guide GS of the valve stem of the motor M of which the seat SP has to be cleaned.
Referring to FIG. 2, the rod 1 slides and travels in a casing 2 which comprises a shell having two spherical portions 2a and 2b. The shell is enclosed in the housing 3 which is subjected to displacements of the table T according to the arrows f1 and f2. The housing 3 accommodates a cylinder having a piston 5. The lower section of the housing 3 comprises a concave portion having sufficient sphericity so as to constitute a fixed seat 3a for resting thereon a lower spherical portion 2b of the shell of the casing 2. Furthermore, a guide
REFERENCES:
patent: 2065173 (1936-12-01), Dars
patent: 2823591 (1958-02-01), Craddock et al.
patent: 3764204 (1973-10-01), Kammeraad
patent: 4099801 (1978-07-01), Korrenn et al.
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