Thread control device for a textile machine, in particular for a shedding device

Abstract

The invention relates to a thread control device for a textile machine, in particular, for a shedding device, with at least one thread guide body ( 31 ) which may be displaced in one displacement direction by means of a positive drive ( 35 ) and in the opposite direction by means of a non-positive, pneumnatic return device ( 36 ). Me return device ( 36 ) thus comprises a cylinder/piston unit ( 64,54 ), the cylinder chamber of which ( 52 ) is connected to a compressed gas source ( 60 ) by means of a valve ( 56 ). An improvement in control is achieved when the valve ( 56 ) comprises a first valve seat ( 72 ) connected to the cylinder chamber ( 52 ) and a second valve seat ( 76 ), between which a valve body ( 82 ), provided with at least one throttle point ( 80 ), may be displaced, pre-tensioned in the rest position by means of a spring ( 84 ) against the first valve seat ( 72 ), in which the throttle point ( 80 ) is ineffective and the valve body ( 82 ) blocks the communication with the compressed gas source ( 60 ) when the valve body ( 82 ) is in contact with the second valve seat ( 76 ).

1 . A thread control device for a textile machine, in particular for a shedding device, said thread control device comprising: at least one thread guide member which is moveable in one direction of movement by means of a positively designed drive and in the opposite direction of movement by means of a nonpositive and pneumatically designed return device, the latter having a cylinder/piston assembly the cylinder chamber of which is connected to a compressed gas source via a valve, wherein the valve has a first valve seat connected to the cylinder chamber and a second valve seat between which a valve member, provided with at least one throttle point is moveable, which valve member, in the basic position, is prestressed against the first valve seat by means of a spring, the throttle point being inactive and the valve member shutting off communication with the compressed gas source when the valve member is against the second valve seat.  
   
   
       2 . The thread control device as claimed in  claim 1 , wherein the valve has a housing at one end of which the first valve seat is formed.  
   
   
       3 . The thread control device as claimed in  claim 2 , wherein the second valve seat is formed on a closing-off part designed with a passage duct.  
   
   
       4 . The thread control device as claimed in  claim 2  wherein the housing is designed cylindrically, in which the piston-like valve member is guided, sealed off with respect to the housing wall.  
   
   
       5 . The thread control device as claimed in  claim 2 , wherein a gap between the valve member and the housing wall of the valve serves as a throttle point.  
   
   
       6 . The thread control device as claimed in  claim 1 , wherein the valve is arranged in the cylinder chamber.  
   
   
       7 . The thread control device as claimed in  claim 1 , wherein the valve is arranged in the lowermost point of the cylinder.  
   
   
       8 . The thread control device as claimed in  claim 1 , wherein a closing-off part of the valve is connected directly to a feed pressure chamber.  
   
   
       9 . The thread control device as claimed in  claim 8 , wherein the feed pressure chamber has an oil separation outlet for oil coming from the cylinder chamber.  
   
   
       10 . The thread control device as claimed in  claim 9 , wherein the oil separation outlet is arranged on a bottom of the feed pressure chamber.  
   
   
       11 . The thread control device as claimed  claim 10 , wherein a connection for compressed air is arranged, at a distance from the bottom of the feed pressure chamber on a lateral wall of the feed pressure chamber.  
   
   
       12 . The thread control device as claimed in  claim 8 , wherein the feed pressure chamber of at least one return device serves as a feed pressure and oil outflow device.  
   
   
       13 . The thread control device as claimed in  claim 1 , wherein a lower portion of the cylinder serves as a valve housing and has a connection for the compressed gas source.  
   
   
       14 . The thread control device as claimed in  claim 13 , wherein an annular stop is arranged inside the cylinder and is designed as a first valve seat connected to the cylinder chamber.  
   
   
       15 . The thread control device as claimed in  claim 14 , wherein the cylinder is closed off by means of the closing-off part, the latter having a sleeve part the free end of which serves as a second valve seat.  
   
   
       16 . The thread control device as claimed in  claim 15 , wherein an oil separation outlet is arranged on the closing-off part.  
   
   
       17 . The thread control device as claimed in  claim 1 , wherein the switching pressure of the valve can be set by a change in the prestressing force of the spring.  
   
   
       18 . The thread control device as claimed in  claim 17 , wherein the prestressing force of the spring can be set from outside.  
   
   
       19 . The thread control device as claimed in  claim 1 , wherein the maximum compression pressure in the cylinder chamber can be set by means of the flow cross section of the throttle point.  
   
   
       20 . The thread control device as claimed in  claim 3 , wherein the housing is designed cylindrically, in which the piston-like valve member is guided, sealed off with respect to the housing wall.