Textiles: knitting – Needles – Pivoted latch
Reexamination Certificate
2000-03-30
2001-04-03
Worrell, Danny (Department: 3741)
Textiles: knitting
Needles
Pivoted latch
Reexamination Certificate
active
06209360
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application claims the priority of German Application No. 199 14 928.3 filed Apr. 1, 1999, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to a latch needle having a head (hook) cooperating with a pivotally supported latch. The latch needle further has a needle cheek which is provided with a sawslot defined between two side walls of the needle cheek. The latch has a latch shank accommodated in the sawslot and provided with a latch hole. The latch needle further has at least one latch bearing which is formed by at least one projection constituted by a plastic deformation of at least one of the cheek side walls. The material from which the projection is formed leaves a depression in the respective side wall. The projection extends into the hole of the needle latch. Latch needles of this type are used, for example, in knitting machines.
The latch may be pivoted into a first position in which the latch lies on the free end of the needle head and a second position in which the latch is swung away from the head and thus opens the same. In this arrangement an accurate support of the latch is very important. The latch has to move freely to ensure that it may be pivoted back and forth by small operating forces. On the other hand, the latch has to be guided with such an accuracy that, in the course of the closing motion, the latch spoon arrives into a precise engagement with the hook. Such a result has to be ensured for the entire service life of the latch needle.
As noted earlier, the latch is usually supported on the latch needle by a pin extending through a latch hole which is provided in the needle latch for this purpose. In the vicinity of the needle head a cheek region is formed which has a sawslot. On both sides of the sawslot side walls are arranged from which a pin is formed or between which a separate pivot pin is held. The latch shank extends between the side walls into the sawslot and journals on the pin.
Various embodiments have become known for forming a pin to support the latch or for inserting a pin into holes provided in the side walls of the needle cheek. Thus, U.S. Pat. No. 3,526,104, to which corresponds German Offenlegungsschrift (application published without examination) 15 85 091 discloses a latch needle having an inserted pivot pin. The holes which are provided for receiving the pivot pin in the side walls of the needle cheek are in alignment with one another and conically flare towards the outer side faces of the needle. The pivot pin is a separately made wire component which is inserted into the aligned holes and is riveted at both ends whereby convex rivet heads are formed.
U.S. Pat. No. 5,509,280 discloses a latch needle in which, for supporting the latch, two obliquely adjoining half pins are provided which are pressed out from the side walls defining the sawslot. The half pins are of asymmetrical configuration related to the pivot axis of the latch. The half pins are formed by plastically deforming the side walls with a suitable puncturing tool. The penetration depth of the tool is not constant along the circumference of each pin, whereby the flow conditions of the material are not uniform along the circumference.
Further, for supporting a latch on a latch needle, it is known from German Patent No. 608,619 to make half pins by plastic deformation of the side walls on both sides of the sawslot. For this purpose, puncturing tools with planar end faces are used. The puncturing tools have at their frontal end a cylindrical bit with a planar end face whose diameter is smaller than the diameter of the half pin to be made.
The half pins form projections which extend into the sawslot and penetrate into the latch hole. The purpose of this arrangement is to ensure a lasting, accurate positioning of the latch.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved latch needle which ensures a durable and accurate functioning of the needle latch.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the latch needle includes a head; a cheek having two facing side walls each having an inner wall face and an outer wall face; a sawslot defined by the inner wall faces of the side walls; and a pivot pin being formed at least on one of the side walls by plastically deforming the side wall. The pivot pin extends from the inner wall face of the side wall into the sawslot. The latch needle further has a first depression provided in the outer wall face of the side wall in alignment with the pivot pin. The first depression includes a bottom having a peripheral region in which a second depression is provided. A needle latch cooperates with the head and has a latch shank accommodated in the sawslot. The latch shank has a hole into which the pivot pin extends for forming a bearing support for the needle latch.
Thus, stated generally, the object of the invention is achieved by increasing the pin's carrier part which is ideally 100% of the latch thickness.
The latch needle according to the invention has, for providing a latch support, at least one projection formed by plastic deformation. The projection extends into the sawslot and penetrates into the latch hole of a needle latch accommodated in the sawslot. The projection thus forms a pin or a half pin for supporting the latch. On the outer side faces of the needle shank, in an axial prolongation of the depression, a further, second depression is provided which preferably extends parallel to the circumference of the pin and may be interrupted or subdivided. The additional depression positively affects the flow of material when the projection (pivot pin) is formed. By virtue of this arrangement it is feasible to obtain a pin or half pins with only a slight bulging of the free end face thereof. Thus, the end face of the pivot pin may be maintained relatively planar so that the size of the lateral pin surface serving for supporting the latch may be maximized. The axially measured height of such a lateral surface is ideally identical to the latch thickness.
In case of a symmetrical construction, both side walls are provided with depressions and each has an additional depression. The pins produced in this manner abut each other approximately in the middle of the sawslot. By virtue of their planar end faces the width of the gap between the lateral surfaces of the two pins, that is, the approximately annular interruption of the latch supporting surface is minimized, regardless of whether the half pins (projections) are welded to one another at their end faces. The obtained maximization of the supporting surface and the only slight deformation of the inner flanks of the sawslot provide for a durable and accurate (that is, a small-clearance) latch support so that latch needles operate with high precision even after a long service. Such a result is made possible by the depression which is provided in the outer side face of the needle and which has at least one further depression adjoining its bottom. The configurations of the depressions may have different embodiments. Thus, for example, the bottom may be surrounded by a circumferentially extending uninterrupted groove and may otherwise be of arcuate or planar shape. It is also feasible to interrupt the groove (that is, the second depression) once or several times. The groove may adjoin directly the wall of the first depression in which case it is then arranged radially externally of the first depression. It is furthermore possible that it is arranged further inwardly and to form an annular step between the wall of the first depression and the groove.
A stepped transitional region may be provided between a groove situated at the outer periphery of the bottom of the second depression and the planar or arcuate middle zone. Such a region may be a conical annular surface or a real step formed as an almost cylindrical annular surface. The annular groove provided in the bottom of the firs
Majer Sigmar
Schuler Bernhard
Groz Beckert KG
Kelemen Gabor J.
Venable
Worrell Danny
LandOfFree
Latch needle having a latch supported on a pin does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Latch needle having a latch supported on a pin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Latch needle having a latch supported on a pin will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2532023