Solenoid valve for air nozzle weaving machines

A solenoid valve, particularly for use in air nozzle weaving machines, has a valve housing with at least one valve inlet and at least one valve outlet. An electromagnetically actuated valve body is arranged in a passage area between the valve inlet and the valve outlet. In order to permit a fast and operationally reliable exchange of the parts of the solenoid valve subjected to wear, it is provided that a fastening flange, the valve body, as well as the electromagnetic drive together form a first valve subassembly which is subjected to a rapid exchange. The valve housing with its connections forms a second valve subassembly which is fixedly arranged on the machine.

BACKGROUND AND SUMMARY OF INVENTION
 This application claims the priority of German patent application
 29909223.2, filed May 28, 1999, the disclosure of which is expressly
 incorporated by reference herein.
 The invention relates to a solenoid valve, particularly for a use in
 weaving machines. Solenoid valves of this type are used, for example, in
 air nozzle weaving machines, for steering the pneumatic woof yarn feeding
 medium to the main and auxiliary blow nozzles.
 In the simplest case, a solenoid valve consists of a valve housing in which
 the valve chamber is arranged with the valve inlet and the valve outlet.
 In the closed condition of the valve, the valve inlet and the valve outlet
 are separated from one another by a valve disk disposed on a valve seat.
 The valve disk is driven by an electromagnetically actuated control
 element and can be lifted off the valve seat such that the passage between
 the valve inlet and the valve outlet is opened up. The valve inlet and
 outlet are connected with hose or tube connections for feeding and
 removing a pressure medium. The electric connection for the
 electromagnetic drive takes place by way of a corresponding connecting
 line.
 If a defect occurs in the case of such a solenoid valve, it has been
 necessary to either exchange the entire valve or to at least remove the
 valve in order to be able to exchange the defective parts. This resulted
 in the disadvantage that the connections for the pressure medium to the
 valve inlet and the valve outlet as well as the electric connecting line
 had to be pulled off before the removal of the valve, which leads to
 considerable expenditures particularly in the case of installation
 positions which are difficult to access. In the case of air nozzle weaving
 machines, it is impossible during the weaving operation to access the
 solenoid valves used for controlling the auxiliary blow nozzles, because
 these solenoid valves are covered by the web of woven fabric moving
 directly over them.
 Another disadvantage is the fact that, when individual components, such as
 the valve disk, are exchanged, the observance of the specified tolerances,
 as, for example, switching times, valve lift, etc., is not ensured if old
 components are paired with new exchange elements.
 It is an object of the invention to improve a solenoid valve of the
 initially mentioned type such that the components subjected to wear can be
 rapidly exchanged.
 This object is achieved according to preferred embodiments of the invention
 by providing a solenoid valve, particularly for a use in air nozzle
 weaving machines, comprising:
 a valve housing with a fluid input, a fluid output and having electric
 contact bushes,
 a first valve body which is arranged in the valve housing and which
 connects an inflow-side hollow space of the first valve housing by an
 inlet integrated in the valve body with an outflow-side valve chamber,
 a second valve body for controlling a fluid flow between the valve chamber
 and a coaxial outlet in the first valve body, and
 a fastening flange which can be rapidly connected with the valve housing
 and which, facing the valve housing, carries the first valve body and
 which, facing away from the valve housing, carries an electromagnetic
 drive, the drive having electric contact elements for the rapid connection
 with the electric contact bushes,
 wherein the fastening flange, the first valve body and the second valve
 body as well as the electromagnetic drive together form a first valve
 subassembly which is subjected to a rapid exchange, and
 wherein the valve housing with its connections forms a second valve
 subassembly which in use is fixedly arranged on the weaving machine.
 The invention is based on the fact that a first valve body is sealingly
 accommodated in a hollow space of the valve housing, in which case at
 least one inlet and one outlet for a pressure medium lead into the hollow
 space of the valve housing, which inlet and outlet can be connected in a
 controlled manner inside the valve housing.
 As the result of the essentially two-part construction of the solenoid
 valve, specifically the valve housing, which has the connections for
 feeding and removing the pressure medium to be steered, the first valve
 body arranged in the valve housing, and, on the other hand, the second
 valve body which carries out the actual valve functions, it is
 advantageously achieved that an exchange of the built-in valve parts can
 be carried out without the removal of the connections for the pressure
 medium, such as hoses and pipes.
 When the first and second valve body are inserted, a fastening flange
 connected with the first valve body rests against the valve housing, in
 which case the valve housing and the fastening flange are connected with
 one another by means of rapidly releasable fastening devices.
 The first valve body, the fastening flange and the electromagnetic drive
 together advantageously form a valve subassembly which can be exchanged as
 a unit.
 Between the first valve body and the valve housing, seals are arranged
 which, on the one hand, provide a sealing off of the valve chamber toward
 the outside and, on the other hand, seal off the inlet and the outlet of
 the valve chamber with respect to one another.
 An easy exchangeability of the valve subassembly is also promoted by the
 fact that a plug-type connector with electric contacts is arranged on the
 valve subassembly, which plug-type connector interacts with a counterpart
 arranged on the valve housing. The plugging of the valve subassembly into
 the valve housing simultaneously establishes the electric connection for
 driving the valve.
 Another advantage of the invention is the fact that a fast and easy
 exchange of the defective valve subassembly can be carried out in that the
 quick fastening between the valve subassembly and the valve housing is
 released and the entire valve subassembly can be exchanged without
 requiring a high-expenditure demounting of the valve. Also, no loose
 single parts occur during the exchange of the valve subassembly, which may
 possibly be lost.
 In addition, the valve subassembly is a pretested and operable unit so
 that, when it is exchanged, no subsequent testing of the exchanged valve
 subassembly is required. The risks of tolerance differences between the
 old and the new parts, which may impair the operability of the valve, are
 therefore eliminated.
 Other objects, advantages and novel features of the present invention will
 become apparent from the following detailed description of the invention
 when considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS
 The solenoid valve has an essentially two-part construction and, on the one
 hand, comprises a valve housing 1 with an approximately pot-shaped hollow
 space 4 which is open on one side. An inlet 2, through which a pressure
 medium is fed, leads into the hollow space 4, as well as an outlet 3 for
 discharging the pressure medium. The pressure medium is fed and removed by
 way of pipes which are not shown.
 The valve housing 1 is fastened on a surface 22 which is formed, for
 example, by the wall of the compressed-air tank of an air nozzle weaving
 machine, which compressed-air tank is situated below the weaving plane.
 On the other hand, the solenoid valve comprises a valve subassembly 5
 essentially consisting of a first valve body 6 which forms a valve chamber
 11 with an inlet 10 and an outlet 17 for the pressure medium. On one side,
 the valve body 6 is arranged on a fastening flange 7 which is adjoined by
 an electromagnetic drive 8 for actuating a second valve body 12, 13.
 The second valve body 12, 13 is guided in the valve chamber 11 while being
 sealed off toward the outside and comprises a valve stem at whose end a
 valve disk is arranged. In the closed condition of the valve, the valve
 disk rests in a sealing manner against the valve seat 9, the inlet 10
 being separated from the outlet 17 of the valve. A damper 14 provides a
 damping of the valve disk impact when the valve is open.
 According to the invention, the first valve body 6 is accommodated in the
 hollow space 4 of the valve housing 1, the inlet 10 of the valve body 6
 being connected by way of the hollow space 4 with the input 2 of the valve
 housing 1, and the outlet 17 of the valve body 6 being connected directly
 with the output of the valve housing 1. The outside wall of the valve body
 6 rests against the inside wall of the valve housing 1 and is sealed off
 toward the outside by means of a seal 15. The area between the inlet 10
 and the outlet 17 is also sealed off by a seal 16 arranged between the
 outside wall of the valve body 6 and the inside wall of the valve housing
 1.
 In FIG. 2 of the drawing figures, the flow of compressed air is indicated
 by arrows. In this case, the second valve body 12, 13 is in a position
 withdrawn from the valve seat 9 of the first valve body 6. This results in
 a flow of the compressed air from the inlet 2 to the outlet 3 of the valve
 housing 1.
 In FIG. 3 of the drawing figures, the second valve body 12, 13 is
 illustrated. The second valve body is a component part which is acted upon
 by the electromagnetic drive 8.
 FIG. 4 of the drawing figures shows the first valve body 6 with seals 15,
 16 placed in grooves, which have no reference numbers. In the installed
 condition, a hollow space 4 is formed between the first valve body shown
 in FIG. 2 and the valve housing 1, and at least one flow duct 1A, which
 starts from the inlet 2, leads into this hollow space 4. At least one
 inlet 10 situated in the edge area of the bottom of the pot-shaped hollow
 space 4 connects the hollow space 4 with the valve chamber 11. Starting
 from the bottom of the valve chamber 11, a truncated-cone-shaped
 projection protrudes into the valve chamber 11, whose free end forms the
 circular-ring-shaped valve seat 9.
 A rotationally symmetrical extension extends coaxially in a direction
 opposite to the truncated-cone-shaped projection. A centrally arranged
 flow duct 17, whose outlet 17A leads into the outlet 3 of the valve
 housing 1, connects the valve seat 9 and the end of the extension. The
 outer circumference of the longitudinal section forming the pot-shaped
 hollow space and the outer circumference of the extension of the valve
 body 6 have ring grooves in which seals 15 and 16 are accommodated.
 The fastening flange 7 of the valve subassembly 5 rests against the valve
 housing 1 and is fastened, for example, by means of quick-release screws
 23. However, any other quick-release fastening can also be used.
 For exchanging the valve subassembly 5, only the fastening screws 23 on the
 fastening flange 7 must be unscrewed so that the valve subassembly 1 can
 be removed from the valve housing 1. This does not affect the connections
 for the pressure medium which are situated on the valve housing 1; that
 is, these connections do not have to be removed when the valve subassembly
 5 is exchanged.
 A pulling-off of the electric connections for the drive 8 of the valve is
 also not required when the valve subassembly 5 is exchanged. This is
 achieved in that a plug-type connector 18 is arranged between the valve
 subassembly 5 and the valve housing 1. When the valve subassembly 5 is
 pushed into the valve housing 1, electric contacts 19 provided on the
 valve subassembly 5 engage with assigned contact bushes 20 and therefore
 establish an electric connection between the connecting line 21 and the
 electromagnetic drive 8.
 The foregoing disclosure has been set forth merely to illustrate the
 invention and is not intended to be limiting. Since modifications of the
 disclosed embodiments incorporating the spirit and substance of the
 invention may occur to persons skilled in the art, the invention should be
 construed to include everything within the scope of the appended claims
 and equivalents thereof.