US2619987A - Tuft-cutting mechanism for axminster carpet looms - Google Patents

Description

UCC 2, 1952 l. B. BASSINDALE 2,619,987

TUFTCUTTING MECHANISM FOR XVINSTER CARPET LOOMS 2 SHEETS--SHEET l Filed 001'.. 18, 1949 vrij... 1111 :ha Il.

Inventor dn/10u42 Attorney;

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I TUFT-CUTTING MECHANISM FOR AXMINSTER CARPET LOOMS Filed Oct. 18, 1949 2 SHEETS--SHEET 2 mala/Q A itorneys Patented Dec. 2, 1952 TUFT-CUTTING MECHANISM FOR AXMINSTER CARPET LOOMS Isaac Bradley Bassindale, Grasscroft, near 01dham, England, assignor to Platt Brothers and Company, Limited, Oldham, England Application October 18, 1949, Serial No. 121,969 In Great Britain October 21, 1948 1 Claim.

'Ihis invention relates to improvements in pile tuft-cutting mechanism for Axminster carpet looms.

In the operation of an Axminster carpet loom as ordinarily constructed, the tuft-cutting operation is performed by front and back cutter knives which cut the pile tufts woven into the fabric from the tube frames which supply the tuft-forming yarn. The cutter knives are usually mounted on heavy cross-bars which extend across the width of the loom and the knives should have cutting engagement with one another throughout their entire length.

It is a desirable feature that the cutting edges of the knives shall be maintained in correct cutting relation along the whole length of the knives to ensure a clean cut of the pile tufts across the full width of the fabric being woven.

Due to the conditions of movement of the front knife in the cutting stroke in which said knife moves forwards and downwards in an inclined plane the cutting edge of the front knife does not engage the cutting edge of the back knife uniformly at all points along said edge with the result that some of the tufts are not properly cut. To correct this undesirable condition it is necessary to adjust the cutting edge of the front knife by raising, or lowering, Certain parts of the knife to restore them to correct cutting relation with the back knife.

The present invention provides tuft-cutting mechanism for an Axminster carpet loom having co-operating front and back knives, in which the movable front knife may be accurately set in order to ensure a uniform pressure of its cutting edge against the back knife with which it co-operates and which is static during the actual cutting operation, and in which the front knife is provided with a multiplicity of independently adjustable pressure points spaced along its full length, whereby in the initial setting of the front knife a twist may be imparted to the blade of said front knife from end to end by pressure applied at certain points along the blade in order that its cutting edge may be adjusted to ensure correct cutting engagement with the back knife during the full cutting stroke, or whereby the cutting edge of said front knife may be subsequently adjusted at any particular point in which a defect has developed in use, said front knife comprising a cutter blade narrower at one end than at the other, and being secured in a knife stock, a cross bar carrying said knife stock and set at a slight angle to said cutter blade, slides, in which the said cross bar is mounted,

means for reciprocating said cross bar in said slides, the contiguous faces of the knife stock and the cross bar being formed with opposed V-grooves, rollers in short lengths interposed in spaced relation between the cross bar and the knife stock and located in said V-grooves, adjustable holding screws each formed with a head and being mounted in spaced relation in said cross Vbar with freedom for slight pivotal movement relatively to said cross bar and each in screw-threaded engagement with the knife stock, there being a holding screw between each pair of rollers, washers each formed with a curved under-surface and respectively interposed between the head of the respective holding screw and the adjacent surface of the cross bar, whereby the pivotal movement of the holding screws permits a slight rocking movement of the knife stock on the aforesaid rollers,v screws screwed into threaded holes in the cross bar and each engaging the respective holding screw to prevent accidental displacement of said holding screws after setting, and pairs of adjustable setscrews screwing into the lower face of the cross bar on opposite sides of the rollers with their heads abutting against the upper surface of the knife stock.

Description will now be given of pile tuftcutting mechanism for Axminster carpet looms constructed according to the present invention, reference being made to the accompanying drawings in which Fig. 1 is a plan View of an adjustable front knife, as viewed from the front of the loom, the view being broken to shorten the figure; Fig. 2 is a plan of the front and back knives, drawn to a smaller scale; Fig. 3 is an end elevation, partly sectional, of the front knife and carrier bar, drawn to a larger scale and viewed in the direction of the arrow A, Fig. l; Figs. 4, 5 and 6 are cross-sectional views taken through the lines IV, V and VI respectively of Fig. 1, drawn to a larger scale. The same reference characters are used to indicate corresponding parts in the several gures of the drawings.

Referring to the drawings, the front cutter knife I0 is secured to a knife stock II which is mounted for limited local rocking or twisting movement on a cross-bar I3 set at a slight angle, e. g., 6D to the blade Ill, and mounted in slides, not shown, the cross-bar I3 being adapted for reciprocating movement in the working of the loom, whereby in the advance movement of the cross-bar I3, the front cutter knife I 0 is advanced in a forward and downwardly inclined path to co-operate with the back cutter knife I4 to sever the tufts woven into the fabric from the tube frames which supply the tuft-forming yarn.

The contiguous faces of the front knife stock II and of the cross-bar I3 are each formed with a relatively shallow V-groove I5, IS respectively, the opposed grooves serving to accomodate short rollers I1 interposed in spaced relation between the knife stock II and the cross-bar I3, the rollers I'I serving as fulcrums for the knife stock II.

The knife stock II is held in position on the cross-bar I3 by holding screws i8, passing through clearance holes I9 spaced along the length of the cross-bar I3 and disposed perpendicularly to the axial centre line of the rollers, the screws I8 engaging internally threaded holes 20 in the knife stock II, there being a holding screw I8 between the adjacent rollers I'I of each pair. Each holding screw I8 is formed with a head I 8a which is accommodated in a recess 2i in the upper face of the cross-bar I3.

A washer 22 having a curved undersurface is interposed between the head ISa of the holding screw I8 and a correspondingly curved seating 2 Ia formed in the floor of the recess 2 I.

There is sufficient clearance between the holding screws I8 and the holes I9 in the cross-bar I3 to permit of a slight rocking movement of the knife stock II on the rollers I'I.

The cross-bar II is furnished with two rows of set- screws 23, 24 arranged on opposite sides of the rollers I'I and spaced between the aforesaid holding screws I8, the heads of the set-screws 23, 241, abutting against the upper surface of the knife stock I I.

In order to prevent accidental displacement of the holding screws I8 after setting, there are provided screws 25 screwed into threaded holes in the carrier bar and each engaging the respective holding screw I8.

When the front knife is first placed in position in the loom with the blade level, the cutting edge of the right-hand end of the blade in relation to the back knife is as shown in Fig. 4.

If the front knife blade be moved in a cutting stroke before being adjusted the cuttting edge of the front knife blade would gradually lose contact with the cutting edge of the back knife; Fig. 5 showing the relative positions of the front and back knives at approximately midposition of the cuttting stroke, and Fig. 6 showing the relative positions at the completion of the cutting stroke.

In Fig. 2 the starting position of the cutting knife I is shown at lil', the first and second middle positions by the dotted lines I2 and |03, respectively, and the final cutting position by the'dot-and-dash lines at |04.

To overcome the difficulty experienced as described with reference to Figs. and 6, when setting the knife blade II) the front knife blade is twisted at points along its length in such manner that it is maintained in correct cutting relation with the back knife during the whole ofthe cutting stroke.

To adjust the front knife Id into position to make correct cutting engagement with the back knife I4, the screws 25 ofthe holding screw, or screws, I8 adjacent to the part of the knife Ill to be adjusted are slackened to free the said holding screw, or screws, I6. If it is desired to raise the cutting edge of the knife to bring it into correct cutting relation with the back knife Ill, the respective set screws 23 on the side of the cross-bar I3 adjacent to the front knife I0 are screwed further into the cross-bar I3 and the registering set screw, or set screws, 2:1 on the opposite side is or are screwed outwardly of the carrier I3. By this means the head, or heads, of the set-screw, or set-screws, 24 remote from the knife I bearing against the surface of the knife stock II cause the knife stock II to have a slight local twisting or rocking movement on the respective roller, or rollers, I'I until the movement is arrested by the head, or heads, of the set-screw, or set-screws, 23 adjacent to the knife lil, when the cutting edge of the front knife Il has been brought into correct cutting relation with the back knife Ill.

The required movement of the holding screw I8 in the respective socket 2| in the cross-bar E3 is permitted by the rocking of the washers 22 on their respective seatings. The holding screw I3 or screws is or are then again secured in adjusted position.

Alternatively, if the cutting edge of the front knife I0 is to be lowered, the adjusting movements of the set- screws 23, 24 are reversed from that previously described.

It will be understood from the foregoing description that the front knife I may be readily adjusted into position to make correct cutting engagement with the back knife Il! at any part or parts of its length by manipulation of the screws 23 or 24 adjacent t0 the part to be adjusted without necessity for removal of the front knife IEB from the loom, whereby the cutting edge of the front knife I may be maintained in correct cutting position with the back knife Id as shown in Fig. 4.

In making a cutting stroke the front knife I d is moved forwardly and downwardly in an inclined plane in the direction of the arrow B, Fig. 3, until the right-hand end of the knife I0 cuts through the rst tuft when the forward movement of this end of the blade ceases while the blade continues to move in a radial direction from the right-hand towards the left-hand, as seen in Fig. 2, in a guillotine action in order to cut the tufts successively across the full width of the carpet, in known manner, this action forming no claimable feature of the present invention.

While the setting operation is usually effected at the initial assembly of the loom it sometimes happens that the cutting edge of the front knife Iii may change its contour after continuous use to such an extent that it does not engage the cutting edge of the back knife Id at all points across the width of the loom, with the result that some of the tufts are not properly severed.

To correct this undesirable condition it is necessary to adjust the cutting edge of the front knife II! by raising or lowering the defective parts of the knife in the manner previously described in order to restore them to correct cutting relation with the back knife. Or the knife blade I5 may be removed, reground and replaced in the carrier I3 and re-set in correct position.

What is claimed is:

Tuft-cutting mechanism for an Axminster carpet loom having a movable front knife comprising a cutter blade narrower at one end than at the other co-operating with a. back knife, in which the movable front knife may be accurately set in order to ensure a uniform pressure of its cutting edge against the back knife with which it co-operates, the back knife being static during the actual cutting operation, and in which the front knife is provided with a multiplicity of independently adjustable pressure points spaced along its full length, whereby in the initial setting of the front knife a twist may be imparted to the blade of said front knife from end to end by the application of pressure at certain points along its blade in order that its cutting edge may be adjusted to ensure correct cutting engagement with the back knife durlng the full cutting stroke, and whereby the cutting edge of said front knife may be subsequently adjusted at any particular point at which a defect may have developed in use, a knife stock in which the cutter blade of the front knife is secured, a cross lbar carrying said knife stock and set at a slight angle to said cutter blade, slides in which said knife stock is mounted, means for reciprocating said cross bar in said slides, the contiguous faces of the knife stock and the cross bar being formed with opposed V-grooves, rollers in short lengths interposed in spaced relation between the cross bar ment with the knife stock, there being a holding screw between each pair of rollers, washers each formed with a curved undersurface and respectively interposed between the head of the respective holding screw and the adjacent surface of the cross bar, whereby the pivotal movement of the holding screws permits a slight rocking movement of the knife stock on the aforesaid rollers, screws screwed into threaded holes in the cross bar and each engaging the respective holding screw to prevent accidental dis,- placement of said holding screws after setting, and pairs of adjustable set-screws screwed into the lower face of the cross bar on opposite sides of the rollers with their heads abutting against the upper surface of the knife stock.

ISAAC BRADLEY BASSINDALE,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS and the knife stock, and located in said V-grooves, adjustable holding screws each Number Name Date formed with a head and being mounted in 25 1,349,621 Head Mar. 15, 1932 spaced relation in said cross bar with freedom 2,379,740 Palmer July 3, 1945 for slight pivotal movement relatively to said 2,441,374 Robb May 11,1948 cross bar and each in screw-threaded engage- 2,512,302 BIlIltOn June 20, 1950

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