Needle-holding unit for a circular knitting machine

Patent metadata

Field	Value
Publication number	US-12091787-B2
Application number	US-202017614480-A
Country	US
Kind code	B2
Filing date	May 21, 2020
Priority date	May 27, 2019
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

A needle-holding unit for circular knitting machines has a structure shaped as a hollow solid of rotation developing around a central axis is configured for turning around said central axis and for supporting a plurality of needles moving so as to produce a knitted fabric. The needle-holding unit exhibits on an outer side at least one working surface, on which a plurality of needle seats is defined, which are placed beside one another and arranged around the central axis. Each of the needle seats movably houses at least a portion of at least one respective needle which can be actuated with an alternate motion along the respective needle seat with a motion of extraction and a motion of return, in order to produce knitted fabric. Each needle seat has an inclined longitudinal development with respect to the central axis. The working surface has a shape as a surface of rotation obtained through the rotation of the inclined needle seats around the central axis, and in particular the working surface is a non-cylindrical, non-conical three-dimensional surface.

First claim

The invention claimed is:

1. A needle-holding unit ( 1 ) for circular knitting machines, configured to be turnably mounted to a supporting structure of a circular knitting machine, the needle-holding unit ( 1 ) having a structure shaped as a hollow solid of rotation developing around a central axis (Z), the needle-holding unit being configured for turning around said central axis and for supporting a plurality of needles (N) moving so as to produce a knitted fabric;
the needle-holding unit ( 1 ) having on an outer side thereof at least one working surface ( 2 ), wherein a plurality of needle seats ( 3 ) placed one beside the other and arranged around said central axis (Z) is defined on the working surface ( 2 );
each one of said needle seats ( 3 ) being configured for movably housing at least one portion of at least a respective needle (N) to be actuated with an alternate motion along the respective needle seat ( 3 ) with a motion of extraction, by which the needle (N) is taken out with its head (H) and with a portion of its stem above of the needle-holding unit through an upper end of the respective needle seat ( 3 ) so as to discharge on its stem the knitted loop previously formed and/or for taking the yarn or yarns supplied on a machine feed, and with a motion of return, so as to form a new knitted loop by holding down the knitted loop previously formed; and
wherein each needle seat ( 3 ) of said plurality of needle seats has a longitudinal development inclined with respect to the central axis (Z), wherein the working surface ( 2 ) has a shape as a surface of rotation obtained through the rotation of said needle seat ( 3 ) around the central axis (Z), and wherein the working surface ( 2 ) is a non-cylindrical, non-conical three-dimensional surface.

2. The needle-holding unit ( 1 ) according to claim 1 , wherein said working surface ( 2 ) is a one-sheeted hyperboloid or hyperbolic hyperboloid.

3. The needle-holding unit ( 1 ) according to claim 1 , wherein said working surface ( 2 ) is a doubly ruled surface.

4. The needle-holding unit ( 1 ) according to claim 1 , wherein the needle-holding unit ( 1 ) is equipped above with a knitting plane (KP) which the upper ends of the needle seats ( 3 ) point towards, destined to receive resting thereon the knitted portions between two adjacent needles (N) while these, after taking the yarn from a machine feed, get back into the respective needle seats ( 3 ),
and wherein the needle-holding unit is equipped with a Cartesian reference system defined by three mutually orthogonal axes, wherein:
a first vertical axis (Z) coincides with said central axis (Z); and
a second horizontal axis (X) and a third horizontal axis (Y) define a horizontal plane, orthogonal to said first axis (Z), traversing the knitting plane (KP),

and wherein the needle-holding unit is equipped with a cylindrical reference system, wherein each point of the working surface may be defined by three coordinates:
a radial coordinate corresponding to the distance of the point from the central axis (Z);
an angular coordinate corresponding to the angular distance with respect to the origin on the horizontal plane; and
an axial coordinate corresponding to the height of the point, calculated in a direction parallel to the central axis (Z), with respect to the horizontal plane.

5. The needle-holding unit ( 1 ) according to claim 1 , wherein the distance from the central axis (Z), calculated on planes parallel to the horizontal plane, of each point of the working surface ( 2 ) varies for each vertical height, along a direction parallel to the central axis, in a non-linear manner.

6. The needle-holding unit ( 1 ) according to claim 1 , wherein:
the working surface ( 2 ) has an upper end ( 5 ) and a lower end ( 6 ), between which a central section is placed, and the distance from the central axis (Z), calculated on planes parallel to the horizontal plane, of the points belonging to the upper end ( 5 ) and to the lower end ( 6 ) is larger than the distance of the points belonging to the central section; or wherein
the working surface ( 2 ) has an upper end ( 5 ) and a lower end ( 6 ), and the distance from the central axis (Z), calculated on planes parallel to the horizontal plane, of the points belonging to the upper end ( 5 ) is larger than the distance of the points belonging to the lower end ( 6 ), or wherein
the working surface ( 2 ) has an upper end ( 5 ) and a lower end ( 6 ), and the distance from the central axis (Z), calculated on planes parallel to the horizontal plane, of the points belonging to the lower end ( 5 ) is larger than the distance of the points belonging to the upper end ( 6 ).

7. The needle-holding unit ( 1 ) according to claim 1 , wherein said working surface ( 2 ) defines a minimum circumference (M) lying on a plane parallel to said horizontal plane and comprising all of its points having a minimum radial distance (rTAN) from the central axis (Z), and wherein the intersection between a plurality of planes parallel to the horizontal plane, each at a different vertical height along the vertical axis (Z), and the working surface ( 2 ) identifies a plurality of horizontal surfaces, each circumference being defined by all of the points of the working surface ( 2 ) placed at the respective height of the circumference itself and at a distance from the central axis (Z) corresponding to the radius of the circumference itself.

8. The needle-holding unit ( 1 ) according to claim 7 , wherein each needle seat ( 3 ) is configured for housing at least one respective needle (N) having a rectilinear shape, and has a bottom surface of the seat, or bottom, on which said at least one respective needle (N) slides, and/or wherein, said needle seat ( 3 ) being inclined with respect to the central axis (Z), the bottom surface of the seat has a point of minimum distance (P) from the central axis (Z) and lies on a bottom plane, said bottom plane being parallel to the central axis (Z) and tangent to a base cylinder of the needle-holding unit, said base cylinder having a radius corresponding to said minimum radial distance (rTAN), and wherein the needle seat ( 3 ) is configured for determining and guiding the sliding of the needle (N) housed by it on the bottom surface on said bottom plane.

9. The needle-holding unit ( 1 ) according to claim 8 , wherein the combination of the inclination of said needle seat ( 3 ) with the three-dimensional shape of said working surface ( 2 ) is such as to defined a linear bottom, lying on the respective bottom plane, tangent to the base cylinder.

10. The needle-holding unit ( 1 ) according to claim 8 , wherein the bottom plane is tangent to the base cylinder in a segment of contact, which is vertical and parallel to the central axis (Z), said segment of contact comprising, i.e. traversing, said point of minimum distance (P), and/or wherein all the needle seats ( 3 ) of said plurality of needle seats have an inclination with respect to the central axis (Z) corresponding to an angle of inclination (α) different from zero, said angle of inclination being the smallest angle formed by each needle seat ( 3 ), on its bottom plane, with the respective segment of contact.

11. The needle-holding unit ( 1 ) according to claim 1 , comprising control devices ( 10 ) associated thereto, arranged outside around the needle-holding unit in a stationary manner and configured for interacting with the needles (N) supported by the needle-holding unit, as a result of the relative rotation between the needle-holding unit ( 1 ), rotating around the central axis (Z), and the control devices, so as to transmit a controlled movement to each needle (N) within the respective needle seat ( 3 ), and t

Assignees

• Santoni & C Spa

Inventors

• Rizzi Stefano
• Andreoli Marco
• Lonati Andrea

Classifications

• D04B15/32

  Cam systems or assemblies for operating knitting instruments · CPC title

• D04B15/14 Primary

  Needle cylinders · CPC title

• D04B15/10 Primary

  Needle beds · CPC title