KNIFE BLOCK FOR A TUFTING MACHINE

• US 3,757,709 A
• Filed: 04/27/1972
• Issued: 09/11/1973
• Est. Priority Date: 04/27/1972
• Status: Expired due to Term

• Current Assignee: James T. Cobble
• Original Assignee: James T. Cobble
• Inventors: Cobble, James T.
• Primary Examiner(s): Boler, James R.
• Assistant Examiner(s): Chan, Wai Ming
• Application Number:
  US05/248,197
• Time in Patent Office: 502 Days
• Field of Search: 112/79R,79A,266 83/698,699,700
• US Class Current: 112/80.6
• CPC Class Codes: D05C 15/24 Loop cutters; Driving mechanisms therefor
• CPC Class Codes: Y10T 83/949 Rectilinearly

Abstract

A knife block for a tufting machine having provision for accurately aligning and connecting the block to an oscillating knife bar. The aligning and connecting structure includes a channel formed in the front surface of the bar, the channel being adapted to closely receive the rear edge portion of the block therein to maintain a predetermined alignment.

Claims

1. In a tufting machine for forming a cut pile fabric and including means for carrying a yarn through a backing fabric to form a plurality of tufting loops therein, the combination therewith of looper means operatively associated with said yarn carrying means for engaging and retaining the tufting loops, and means operatively associated with said looper means for severing the tufting loops while retained by said looper means and including a knife bar mounted for oscillatory movement in relation to said looper means and defining a front surface, a knife block defining a rear edge portion positioned opposite said knife bar front surface, a knife carried by said knife block and adapted to cooperate with saId looper means in severing the yarn loop upon relative oscillatory movement between the knife bar and looper means, and means for connecting said knife block to said knife bar in a predetermined angular relationship such that the knife is maintained in a predetermined relationship with respect to said looper means, said connecting means including a channel formed in said bar front surface, said channel having a cross-sectional outline closely conforming to the cross-sectional outline of said block rear edge portion and closely receiving the same therein, a cylindrical opening extending into said bar front surface and communicating with said channel, a cylindrical shaft having one end connected to said knife block rear edge portion and extending outwardly therefrom and closely received within said cylindrical opening, and means for locking said shaft in said opening.

2. The tufting machine as defined in claim 1 wherein said channel has a U-shaped cross-sectional outline defining a planar medial surface and opposed side edge surfaces, said block rear edge portion has a U-shaped cross-sectional outline defining a planar rear edge surface and oppositely facing side edge surfaces, whereby said block planar rear edge surface closely overlies said channel medial surface and said channel side edge surfaces closely overlie said block side edge surfaces to thereby preclude relative rotational movement between said knife block and said knife bar.

3. The tufting machine as defined in claim 2 wherein said means for locking said shaft in said opening includes a threaded aperture extending into said bar and communicating at substantially right angles with said cylindrical opening, and a locking screw adapted to be threadedly received in said threaded aperture and engage said shaft.

4. The tufting machine as defined in claim 3 wherein said cylindrical shaft and cylindrical opening define a common axis extending substantially perpendicular to said channel medial surface and said knife block planar rear edge surface.

5. The tufting machine as defined in claim 4 wherein said knife bar has a rectangular cross-section defining a vertical direction and a horizontal direction, and said channel side edge surfaces define planes which extend substantially perpendicular to said medial surface and at an angle of about 12* from said vertical direction and at an angle of about 5* from said horizontal direction.

6. In a tufting machine for forming a cut pile fabric including means for carrying a plurality of yarns through a backing fabric to form plurality of tufting loops therein, looper means operatively associated with said yarn carrying means for engaging and retaining the tufting loops, means operatively associated with said looper means for severing the tufting loops while retained by said looper means and including a knife bar mounted for oscillatory movement in relation to said looper means, a plurality of knife blocks carried by said knife bar, and at least one knife carried by each knife block and adapted to cooperate with said looper means in severing the yarn loops upon relative oscillatory movement between the knife bar and looper means, the improvement therein comprising means for connecting said knife blocks to said knife bar in a predetermined angular relationship such that the knives are maintained in a predetermined relationship with respect to said looper means, said connecting means including a front surface on said knife bar, said front surface including a plurality of closely spaced, vertically directed channels along the longitudinal length thereof, each of said channels having a U-shaped cross-sectional outline, a rear edge portion on each of said knife blocks, each of said rear edge portions defining a U-shaped cross-sectional outline generally conforming to the cross-sectional outline of said channels and closely received within one of said channels, a plurality of cylindrical openings extending into saiD bar with one of said openings communicating with each of said channels, a cylindrical shaft having one end connected to the rear edge portion of each knife block and being closely received within the associated cylindrical opening, and means for locking each shaft in the associated opening.