Motors: expansible chamber type – With motive fluid valve – For double-acting motor
Patent
1990-04-05
1992-03-24
Look, Edward K.
Motors: expansible chamber type
With motive fluid valve
For double-acting motor
91443, 137599, 137854, 251 60, 251122, F15B 1108
Patent
active
050977474
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
The invention relates to apparatus in which the speed of a double-acting pneumatic cylinder is adjusted for each travel direction by means of a unidirectional flow limiter placed between the orifice of the pressure cylinder through which the air escapes during the adjusted stroke and its directional control valve. Such an apparatus, also called adjuster, comprises an adjustment screw fast with a needle-valve for limiting at will the flow of air escaping through its seat which thus determines the speed of the cylinder. So that, in the other travel direction, the drive fluid is admitted at full flow into this same chamber, the adjuster further comprises a unidirectional valve opening in the direction of the intake flow and closing in the direction of the escape flow. Conventional adjusters only allow a single adjusted speed for one travel direction of the pressure cylinder, which speed is established at the outset and remains constant. Now, in a large number of cases, it would be desirable to have, during each stroke and on demand, two speeds of different values, which would increase the operating rates while avoiding end of travel shocks, or else allowing a rapid speed of a tool to be readily obtained followed by a slower working speed.
The present invention makes it possible to attain this aim, by providing two-speed adjusters, the passage from one speed to a second adjusted lower speed being achieved by a pneumatic control signal arriving in the apparatus and the reverse operation by disappearance of this signal.
Various prior art arrangements are known including these as follows:
______________________________________ Adams 3,090398
Britain 2,032,581
France 2,343,280 (U.S. Pat. No. 4,214,607 and
U.S. Pat. No. 4,171,007)
France 2,363,015 (U.S. Pat. No. 4,287,812 and
U.S. Pat. No. 4,192,346)
______________________________________
metering systems of various sorts and of various manufactures and the like
as well as methods of their construction, but none of them whether taken
singly or in combination disclose the specific details of the combination
of the invention in such a way as to bear upon claims of the present
invention.
SUMMARY OF THE INVENTION
According to the invention, a controlled connector-adjuster comprises three connectable orifices; the first orifice is connected to one of the orifices of the pressure cylinder through which the air leaves in the direction of the stroke whose speed it is desired to adjust; the second orifice is connected to the corresponding orifice of the directional control valve and the third orifice is connected to a control pipe. The air escaping from the pressure cylinder during the stroke flows from the first to the second orifice and its flowrate through a seat depends on the position of a needle-valve which controls the flow section thereof. This needle-valve is formed by the end of a piston sliding sealingly by means of a seal in its cylindrical housing and which may be subjected, on its face opposite the needle-valve, to the pressure of a signal coming from outside. This signal causes the piston to move in the direction of the seat and since this stroke is limited by the internal end of a screw which can be operated from outside against which it abuts by its needle-valve end, the flowrate of the escaping air passing through the apparatus, and so the speed of the pressure cylinder, thus depends on the adjustment of this screw. In this simplified version of the apparatus, in the absence of the control signal, the pressure passing through the adjuster in one direction or the other pushes the piston back fully into the opening of the seat and such an apparatus only allows a single adjusted speed introduced by a control signal. In preferred versions of application of the invention, the stroke of the piston on opening the seat may also be limited by a second adjustment screw opposite the first one, against which it abuts by its end opposite the needle-valve; this second screw adjusting a pressu
REFERENCES:
patent: 3090398 (1963-05-01), Adams
patent: 4073311 (1978-02-01), McGeachy
patent: 4132153 (1979-01-01), Grotness et al.
patent: 4192346 (1980-03-01), Iizumi
patent: 4421292 (1983-12-01), Matsui et al.
patent: 4432385 (1984-02-01), Legris
patent: 4601366 (1986-07-01), Blain
patent: 4619287 (1986-10-01), Hama et al.
patent: 4741249 (1988-05-01), Legris
Legris S.A.
Look Edward K.
Mattingly Todd
Plottel Roland
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