US2830446A - Camming slide for hand knitting machines - Google Patents

Description

April 15, 1958 A. OPAWA 2,830,446

. CAMMING sum: FOR HAND KNITTING MACHINES Filed March 17, 1955 INVENTOR: AUGUST OPAWA United States, Patent CAMMING SLIDE FOR KNITTING MACHINES August 'Opawa, Vienna, Austria Application March-17, 1955, Serial 'No. 494,867'

3 Claims. (Cl. 66-3) receive a thread or yarn which is formed into loops as the movable pins, which are staggered with respect to the stationary pins, are withdrawn past the latter by a camming slide. This camming slide may comprise an elongated bar with a wedge-like extremity formed by a leading edge which encloses an acute angle with the principal dimension of the slide; the width of the slide determines the extent of displacement of the movable pins and, thereby, the length of the loops thus formed.

When the length of the loops is to be varied, slides of different width may be used or else a single slide of adjustable width may be employed. It has been found, as stated in the aforementioned patent, that the resulting variation in yarn tension may be compensated by modifying the angle of the leading edge (hereinafter termed as lead angle), smaller angles corresponding to larger tensions since the resulting lengthening of the leading edge increases the number of pins simultaneously displaced by the camming slide.

While it is thus possible to provide an adjustable slide maintaining at least approximately constant tension for ditferent loop lengths, the necessity of varying both the efltective width and the lead angle of the slide appears to require the provision of separate means for controlling these two parameters. The present invention has for its object the provision of means for simultaneously, and in a mutually compensating manner, adjusting both the slide width and the lead angle so as to maintain a substantially constant yarn tension.

In accordance with the invention, the above object is realized by the provision of a transversely displaceable cam member on the slide, in combination with a pivoted lever arm urged by suitable means (e. g. a spring) into contact with this cam member and enclosing with the principal slide dimension an angle varying in response to the displacement of the cam member. The principal slide dimension, which is parallel to the two rows of pins, is defined by an edge of the slide along which the latter is guided in a support and which together with an edge of the cam member, parallel to this guiding edge, determines the effective width of the slide. The guiding edge, the parallel edge of the cam member, and the leading edge of the pivoted lever arm represent, roughly at least, three edges of a trapezoid; this trapezoid may be completed by a second pivoted lever arm, symmetrical to the first one, which determines the lead angle of the slide when its direction of movement is reversed.

The invention will be described in greater detail with reference to the accompanying drawing in which:

Fig. l is a fragmentary sectional elevational view of a machine generally similar to the one disclosed in the aforementioned U. S. Patent No. 2,690,659; and

Fig. 2 is a bottom view of the slide, taken on the line II-II of Fig. 1.

In the drawing there is shown a stationary support 20 upon which there aremounted a series of fixed pins 21 (only oneshown) co-operating with a series of movable pins 22a, 22b slidably held in the support 20. This support is shown provided at 2 with a guide rail embracing an edge 1 of the slide 1, the latter being guided along its opposite edge 1" by a similar rail (not shown). .Each pin 22a, 22b isprovided with an upward spur 12a, 12b.

Slide 1 carries a handle 3 and is provided on its underside with rails 5 engaging a cam member 4 for silding movement at right angles to the principal edges 1, 1". Member 4 has an edge 4' parallel to edges 1', 1" as well as a pair of slanting edges 4a, 4b which together with edge 4' define a trapezoidal head. The positioning of cam member 4 is controlled by a knob 8 which threadedly engages a bolt 23 passing through a slot 6 in slide 1; bolt 23 is surrounded by a sleeve 7 which co-operates with knob 8 to clamp the member 4 in a selected position.

A pair of lever arms 10a, 10b are pivoted to slide 1 at 9a, 9b and are urged by springs 11a, 11b into contact with cam edges 4a, 4b, respectively. Slide 1 also carries a bracket 13 whose generally trapezoidal wings 13a, 13b are shiftable, by means here simply shown as a screw 24 guided in a slot 25 of slide 1, between a position in the path of pin spurs 12a, 12b (full lines) and a retracted position (dot-dash lines, Fig. 2). Wings 13a, 13b serve to restore the movable pins from their operative position (pin 22a) to normal (pin 22b); they play no part in the tensioning movement of the pins which serves to draw the yarn 26 into loops With the wings 13a, 13b retracted, and with all movable pins assumed to 'be in their normal position illustrated for pin 22b, a displacement of slide 1 in the direction of the arrow (Fig. 2) will bring the edge 4a of cam member 4 and its continuation, the outer edge of lever 1011, into successive engagement with the spurs 12a, 12b of all the movable pins, thereby camming them into their operative position illustrated for pin 22a. The length of the stroke of the pins, indicated at x in Fig. 1, will thus be seen to depend on the spacing of edges '1 (or 1") and 4', hence on the position of member 4 relative to slide 1. On the other hand, the angle on enclosed between these edges and arm 9a, representing the aforementioned lead angle, is also varied by an adjustment of member 4, the sense of variation of this angle being such as to have an effect upon the tension of yarn 26 opposite to the eifect resulting from the adjustment of cam member 4. Thus, if this member is displaced to the right, the effective width of slide 1 increases but does not lead to a substantial rise in yarn tension since, owing to the greater steepness of that part of the leading edge which is represented by lever 10a, the number of movable pins simultaneously displaced by the slide remains the same. The same is true when the member 4 is moved to the left for a reduction in loop length.

Although the pins 22a, 22b have been illustrated as simple rods, it will be understood that the invention is also applicable to pins of the gripper type enabling the knitting of both knit-purl and purl-purl patterns.

I claim:

1. In a hand knitting machine, in combination, a support, a row of stationary pins on said support, a row of movable pins staggered with respect to said stationary pins, means on said support guiding said movable pins for sliding movement transverse to said rows, an elongated o camming slide, means on said support guiding said slide for longitudinal movement parallel to said rows, a cam Patented Apr. 15, 1958..

member adjustably mounted on said slide for displacemcnt transverse to said rows, means for locking said cam member against displacement, said cam member being provided with a substantially trapezoidal head having an. edge parallel to said rowsland a pair of oppositely inclined cam edges joined to said parallel edge, a pair of arms pivotally mounted on said slide approximately in line with said cam edges, respectively, spring means urgingan extremity of each of said arms into contact with a respective one of said cam edges, and a projection associated with each of said movable pins, said projection extending into the path of movement of a roughly trapezoidal cam consisting of said arms and said head.

2. The combination according to claim 1, further comprising retractable cam means on said slide engageable with said projections for restoring said movable pins to a normal position following displacement thereof by said trapezoidal cam.

3. The combinationaccording to claim 2, wherein said retractable cam means comprises a pair of substantially trapezoidal cam elements positioned on opposite sides of said cam member.

References Cited in the file of this patent UNITED STATES PATENTS 250,218 Dodge Nov. 29, 1881

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