Controllable output brake, thread feed device as well as projectile or gripper weaving machine

A controllable output brake in a thread feed device for projectile or gripper weaving machines, comprising a stationary storage drum which has thread supplied thereto and stored thereon in windings and from which said thread is drawn off discontinuously and overhead into a shed, said storage drum having a rotationally symmetric brake surface, said output brake including an elastically deformable thread brake element, which said thread brake element is adapted to be pressed against said brake surface and is provided with an outer supporting ring, said supporting ring being closed in the circumferential direction and arranged in a holding member encompassing the storage drum in a contact-free manner, a drive control unit and a displacement drive which is arranged in the holding member and is adapted to be controlled by means of said drive control unit when the thread feed device and the weaving machine are in operation, said displacement drive acting on the supporting ring and being used for varying the force with which the thread brake element is pressed against the brake surface, comprising the improvement wherein the supporting ring of the thread brake element is provided with a central portion that is deformable relative to the brake surface axially and elastically in two opposite directions, said supporting ring being supported in the holding member in an axially immovable manner with respect to the holding member, said displacement drive comprising at least one push drive provided on the holding member for each of said axial deformation directions of said central portion, said push drive operating parallel to the axis of the storage drum and acting directly on said deformable central portion, a ring element which is concentric with the axis of the storage drum being supported on said holding member in an axially displaceable manner, said ring element having a pushing end which is in alignment with the central portion and is adapted to be acted upon by said at least one push drive so as to displace said ring element between a release position defined by a first stop of the holding member and a passive position defined by a second stop of the holding member, said central portion being, at said release position, elastically deformed by the pushing end in the axial direction relative to the supporting ring, whereas, at said passive position, the pushing end will at most abut approximately weakly on said central portion.

A projectile weaving machine comprising at least one thread feed device provided with a controllable output brake, said output brake comprising a stationary storage drum which has thread supplied thereto and stored thereon in windings and from which said thread is drawn off discontinuously and overhead into a shed, said storage drum having a rotationally symmetric brake surface, said output brake including an elastically deformable thread brake element, which said thread brake element is adapted to be pressed against said brake surface and is provided with an outer supporting ring, said supporting ring being closed in the circumferential direction and arranged in a holding member encompassing the storage drum in a contact-free manner, a drive control unit and a displacement drive which is arranged in the holding member and is adapted to be controlled by means of said drive control unit when the thread feed device and the weaving machine are in operation, said displacement drive acting on the supporting ring and being used for varying the force with which the thread brake element is pressed against the brake surface, the supporting ring of the thread brake element being adapted to be moved in said holding member in the axial direction of the storage drum with a predetermined amount of axial play relative to the brake surface in two opposite directions, said displacement drive comprising at least one push drive for each of said directions of movement of the supporting ring which said push drive is connected to the holding member and operates exclusively parallel to the axis of said storage drum, said push drive acting directly on the supporting ring and being adapted to be used for positioning said supporting ring on a holding-member contact area located opposite thereto in the respective direction of movement, said projectile weaving machine further comprising a thread brake controlled in dependence upon the weaving cycle as well as a take-up device between the output brake and the shed, the drive control unit of the output brake being connected to a control of the controlled thread brake or of the weaving machine in such a way that, when the controlled thread brake is being disengaged, the braking effect of the output brake can be reduced approximately synchronously until the thread brake element abuts approximately weakly on the brake surface, and, when the controlled thread brake is being engaged, said braking effect can be increased approximately synchronously, preferably slightly in advance, until a maximum value has been reached, which is predetermined by the basic axial adjustment of a holding-member carriage.

A gripper weaving machine comprising at least one thread feed device provided with a controllable output brake, said output brake comprising a stationary storage drum which has thread supplied thereto and stored thereon in windings and from which said thread is drawn off discontinuously and overhead into a shed, said storage drum having a rotationally symmetric brake surface, said output brake including an elastically deformable thread brake element, which said thread brake element is adapted to be pressed against said brake surface and is provided with an outer supporting ring, said supporting ring being closed in the circumferential direction and arranged in a holding member encompassing the storage drum in a contact-free manner, a drive control unit and a displacement drive which is arranged in the holding member and is adapted to be controlled by means of said drive control unit when the thread feed device and the weaving machine are in operation, said displacement drive acting on the supporting ring and being used for varying the force with which the thread brake element is pressed against the brake surface, the supporting ring of the thread brake element being adapted to be moved in said holding member in the axial direction of the storage drum with a predetermined amount of axial play relative to the brake surface in two opposite directions, said displacement drive comprising at least one push drive for each of said directions of movement of the supporting ring which said push drive is connected to the holding member and operates exclusively parallel to the axis of said storage drum, said push drive acting directly on the supporting ring and being adapted to be used for positioning said supporting ring on a holding-member contact area located opposite thereto in the respective direction of movement, said gripper weaving machine further comprising a presenter gripper and a receiver gripper, which are adapted to be cooperatingly driven, wherein the drive control unit of the output brake is connected to a control device for the presenter gripper and the receiver gripper by means of which the braking effect of the output brake can be varied several times between a minimum and a maximum value in dependence upon the movements of said presenter gripper and said receiver gripper during each picking cycle.

A gripper weaving machine comprising at least one thread feed device provided with a controllable output brake, said output brake comprising a stationary storage drum which has thread supplied thereto and stored thereon in windings and from which said thread is drawn off discontinuously and overhead into a shed, said storage drum having a rotationally symmetric brake surface, said output brake including an elastically deformable thread brake element, which said thread brake element is adapted to be pressed against said brake surface and is provided with an outer supporting ring, said supporting ring being closed in the circumferential direction and arranged in a holding member encompassing the storage drum in a contact-free manner, a drive control unit and a displacement drive which is arranged in the holding member and is adapted to be controlled by means of said drive control unit when the thread feed device and the weaving machine are in operation, said displacement drive acting on the supporting ring and being used for varying the force with which the thread brake element is pressed against the brake surface, the supporting ring of the thread brake element being provided with a central portion that is deformable relative to the brake surface axially and elastically in two opposite directions, said supporting ring being supported in the holding member in an axially immovable manner with respect to the holding member, said displacement drive comprising at least one push drive provided on the holding member for each of said axial deformation directions of said central portion, said push drive operating parallel to the axis of the storage drum and acting directly on said deformable central portion, a ring element which is concentric with the axis of the storage drum being supported on said holding member in an axially displaceable manner, said ring element having a pushing end which is in alignment with the central portion and is adapted to be acted upon by said at least one push drive so as to displace said ring element between a release position defined by a first stop of the holding member and a passive position defined by a second stop of the holding member, said central portion being, at said release position, elastically deformed by the pushing end in the axial direction relative to the supporting ring, whereas, at said passive position, the pushing end will at most abut approximately weakly on said central portion, said gripper weaving machine further comprising a presenter gripper and a receiver gripper, which are adapted to be cooperatingly driven, the drive control unit of the output brake being connected to a control device for the presenter gripper and the receiver gripper by means of which the braking effect of the output brake can be varied several times between a minimum and a maximum value in dependence upon the movements of said presenter gripper and said receiver gripper during each picking cycle.