GB1566469A

GB1566469A - Bistaple pneumatic relay

Info

Publication number: GB1566469A
Application number: GB5454076A
Authority: GB
Original assignee: Crouzet SA
Current assignee: Thales Avionics SAS
Priority date: 1976-01-23
Filing date: 1976-12-31
Publication date: 1980-04-30
Also published as: DE2700410A1; IT1065763B; FR2339081B1; FR2339081A1

Description

(54) BISTABLE PNEUMATIC RELAY (71) We, CROUZET, a French Corporate Body, of 128 Avenue de la Republique, 75011 Paris, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to bistable pneumatic relays, such as distributors, logic cells or bistable memories.

In known pneumatic devices of this type, sealing between various chambers and movable parts is either provided by O-ring seals whose friction ensures the bistable effect in the absence of pressure but with the risk of damage through rolling and gunitning, or without seals but employing very close tolerances and well finished surfaces to limit leakage.

It is an aim of the present invention to provide pneumatic relays cumulating the advantages of the short stroke valve type and the advantages of the seals technique, i.e., a bistable state obtained through friction without experiencing the disadvantages hereabove mentioned.

With this aim in view the present invention provides a bistable pneumatic relay of the slide type having a pressure port, two exhaust ports and two piloting ports, whose pressure port and both exhaust ports communicate with a valve chamber vii three annular grooves spaced equidistantly from each other in the internal wall of the chamber, characterized in that the slide has three double seals integral therewith, each seal comprising a resilient 0-ring seal capped with a flat ring whose respective widths are slightly greater than the half stroke of the slide, whereby in movement of the slide from a central to either of two end positions an opposite end one of said annular grooves is covered by a respective seal before the central one of said groove is uncovered by a respective seal.

The invention will hereinafter be further described by way of example with reference to the accompanying drawing which is a sectional view of a slide pneumatic relay constructed in accordance with the invention.

The illustrated valve comprises a housing 1 within which a valve member 6 is slidingly disposed. A pressure duct PA, outlet ducts S1, S2, exhaust ducts El, E2 and piloting ducts P1, P2 provide communication between the interior and the exterior of the housing 1.

Three equidistant rings 5 are arranged on the valve member 6 and urged into sliding sealing engagement with the interior walls of the housing 1.

Resilient O-ring seals 4 automatically and evenly compensate for wear of the rings 5 by applying a steady radially outwardly dlrected force on each ring 5.

Both exhaust ports E" E and the pressure port PA are communicating with the outlet ducts S, and S, through three equidistant internal circular grooves 3, 3'.

Each of the rings 5 has a longitudinal extent slightly greater than half the stroke of the valve member 6 so that when the valve member 6 moves from the illustrated central position to one of two end positions a corresponding one of grooves 3 is covered before the central ring 5 uncovers groove 3'. Thus in each of the two end positions of the valve member 6 one of grooves 3 is open, one closed, and the central groove 3' is open.

Advantageously, the device according to the invention may be used for the construction of bistable pneumatic relays or distributors such as those used in industrial pneumatic techniques.

WHAT WE CLAIM IS: 1. A bistable pneumatic relay of the slide type having a pressure port, two outlet ports, two exhaust ports and two piloting ports, whose pressure port and both exhaust ports communicate with a valve chamber via three annular grooves spaced equidistantly from each other in the internal wall of the chamber, characterized in that the slide has three double seals integral therewith, each seal comprising a resilient O-ring seal capped with a flat ring whose respective widths are slightly greater than the half stroke of the slide, whereby in movement of the slide from a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (54) BISTABLE PNEUMATIC RELAY (71) We, CROUZET, a French Corporate Body, of 128 Avenue de la Republique, 75011 Paris, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to bistable pneumatic relays, such as distributors, logic cells or bistable memories. In known pneumatic devices of this type, sealing between various chambers and movable parts is either provided by O-ring seals whose friction ensures the bistable effect in the absence of pressure but with the risk of damage through rolling and gunitning, or without seals but employing very close tolerances and well finished surfaces to limit leakage. It is an aim of the present invention to provide pneumatic relays cumulating the advantages of the short stroke valve type and the advantages of the seals technique, i.e., a bistable state obtained through friction without experiencing the disadvantages hereabove mentioned. With this aim in view the present invention provides a bistable pneumatic relay of the slide type having a pressure port, two exhaust ports and two piloting ports, whose pressure port and both exhaust ports communicate with a valve chamber vii three annular grooves spaced equidistantly from each other in the internal wall of the chamber, characterized in that the slide has three double seals integral therewith, each seal comprising a resilient 0-ring seal capped with a flat ring whose respective widths are slightly greater than the half stroke of the slide, whereby in movement of the slide from a central to either of two end positions an opposite end one of said annular grooves is covered by a respective seal before the central one of said groove is uncovered by a respective seal. The invention will hereinafter be further described by way of example with reference to the accompanying drawing which is a sectional view of a slide pneumatic relay constructed in accordance with the invention. The illustrated valve comprises a housing 1 within which a valve member 6 is slidingly disposed. A pressure duct PA, outlet ducts S1, S2, exhaust ducts El, E2 and piloting ducts P1, P2 provide communication between the interior and the exterior of the housing 1. Three equidistant rings 5 are arranged on the valve member 6 and urged into sliding sealing engagement with the interior walls of the housing 1. Resilient O-ring seals 4 automatically and evenly compensate for wear of the rings 5 by applying a steady radially outwardly dlrected force on each ring 5. Both exhaust ports E" E and the pressure port PA are communicating with the outlet ducts S, and S, through three equidistant internal circular grooves 3, 3'. Each of the rings 5 has a longitudinal extent slightly greater than half the stroke of the valve member 6 so that when the valve member 6 moves from the illustrated central position to one of two end positions a corresponding one of grooves 3 is covered before the central ring 5 uncovers groove 3'. Thus in each of the two end positions of the valve member 6 one of grooves 3 is open, one closed, and the central groove 3' is open. Advantageously, the device according to the invention may be used for the construction of bistable pneumatic relays or distributors such as those used in industrial pneumatic techniques. WHAT WE CLAIM IS:

1. A bistable pneumatic relay of the slide type having a pressure port, two outlet ports, two exhaust ports and two piloting ports, whose pressure port and both exhaust ports communicate with a valve chamber via three annular grooves spaced equidistantly from each other in the internal wall of the chamber, characterized in that the slide has three double seals integral therewith, each seal comprising a resilient O-ring seal capped with a flat ring whose respective widths are slightly greater than the half stroke of the slide, whereby in movement of the slide from a central to either of two end positions an op posite end one of said annular grooves is covered by a respective seal before the central one of said grooves is uncovered by a res pective seal.

2. A bistable pneumatic relay substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.