Knife holding apparatus

Abstract

An improved knife holding apparatus for use with a rotating cutting roll and cooperating anvil roll of the type used to cut elongated sheet is disclosed. The apparatus is attached to the cutting roll and is particularly useful in making transverse cuts relative to the movement of the sheet as it passes between the cutting and anvil rolls. The apparatus has a block with a curved bottom surface conforming with the curvature of a slitting or slotting head to which it is attached. The apparatus also has a holding bar pivotally attached to the block and movable through a limited arc. A threaded bolt tightens a clamp member against a contact surface for holding an elongated cutting knife therebetween and a pair of set screws are operable to adjust the elevation of the cutting knife relative to the holding bar. A resilient shock pad is located between the holding bar and block generally beneath the cutting knife for reducing shock that occurs during a cutting operation.

Description

The present invention generally relates to apparatus for making cuts in a series of separate places or in a continuous sheet material at a production line or the like, and more particularly, to apparatus for holding a cutting knife in a cutting head and cooperating anvil head apparatus.

The cutting of rolling paper stock or other sheet material by using a pair of cooperating rolls with a knife or sharp edge on one head mounted on a shaft and an anvil or striking surface on another shaft is well known and extensively used in the packaging industry as well as many other industries. Knife holding apparatus for the cutting heads have undergone changes which permit some resilient movement of the knife edge relative to the anvil to reduce the shock or impact that occurs during operation and thereby prolong the effective life of the cutting edge of the knife and also prevent scoring of the anvil surface. While the incorporation of a resilient shock pad may effectively extend the life of the cutting edge and minimize scoring of the anvil, it may be only marginally worthwhile in its total effect, particularly if the resilient member or pad quickly wears out. Down time, maintenance and repair are usually costly and inconvenient regardless of the source of the problem.

Accordingly, it is an object of the present invention to provide an improved cutting knife holding apparatus which incorporates a resilient shock reducing member, permits efficient and easy adjustment of the cutting knife and experiences a minimum of down time and operational maintenance.

Other objects and advantages will become apparent upon reading the following detailed description, in conjunction with the attached drawings, in which:

FIG. 1 is a perspective view illustrating the knife holding apparatus embodying the present invention in the environment of cutting and anvil heads and shafts with sheet stock passing therebetween;

FIG. 2 is an enlarged top plan view of the apparatus embodying the present invention;

FIG. 3 is a front view of the apparatus shown in FIG. 2; and

FIG. 4 is a cross-section taken generally along the line 4--4 in FIG. 2.

Turning now to the drawings and particularly the perspective view of FIG. 1, the invention will be broadly described in conjunction with the environment or apparatus with which it is used. Sheet stock such as corrugated cardboard 10 or the like is shown moving in the direction illustrated by the arrow and between an upper slotting head 11 on a shaft 12 and lower anvil head 13 on a shaft 14. The slotting head 11 on the shaft 12 is shown to carry a slotting knife 16 for making a longitudinal cut in the sheet, as well as apparatus indicated generally at 18 embodying the present invention, which holds a cutting knife 20 that is adapted to make transverse cuts in the sheet stock 10 such as is illustrated at 22. It should be readily understood that both the upper and lower shafts rotate in the directions indicated thereon and the knives 16 and 20 perform the cutting operation as the sheet moves to left as shown in the drawings. It should also be understood that adjustment of the elevation or height of the knife 20 may be required depending upon the thickness of the stock being cut or for altering the cutting depths for different flute thicknesses of corrugated cardboard or the like or for merely aligning the apparatus in the event it becomes out of line. The slotting head 11 is laterally adjustable along the shaft 12.

In accordance with the present invention, and referring to the knife holding apparatus 18 shown in FIGS. 2-4, it includes a block, indicated generally at 26, which is attached to the slotting head 11, typically through the use of a T-bolt (not shown) that extends through an elongated slot 28 that is oversized to permit adjustment of the cutting knife along the circumference of the slotting head. The block 26 has a lower or bottom surface 30 that is preferably of a curvature substantially similar to the surface of the head 11 for accurate positioning. The apparatus 18 also has a holding bar, indicated generally at 32, which is attached to the block 26 and which is adapted to hold the elongated cutting knife 20, the cutting edge of which is shown at 36. The holding bar 32 has a tongue portion 38 with an aperture 40 therein adapted to receive a socket head shoulder screw 42 or the like for pivotally connecting the holding bar 32 to the block 26. In this regard, the block 26 has a central recess 44 for receiving the tongue 38, the sidewall extensions 46 of the block 26 having similar apertures 48 and 50 for receiving the screw 42, the aperture 50 being tapped for receiving the threaded end portion of the socket head shoulder screw 42. Thus, the holding bar is attached to the block 26 at this singular location and is thereby allowed a limited arc of movement around the pivot defined by the set screw 42.

To limit the movement to a relative small arc, the aperture 40 in the tongue 38 is positioned a predetermined distance d.sub.1 from the end surface of the tongue and, by virtue of the small distance d.sub.2 between the bottom surface of the tongue 38 and the horizontal surface of the recess 44, the holding bar 32 will only be capable of moving a short distance upwardly before the tongue makes contact with the horizontal surface of the recess 44.

To hold the cutting knife 20, the holding bar 32 is provided with generally horizontal and vertical contact surfaces 52 and 54, respectively, against which either the cutting blade 20 or a clamp member 56 bears. In this regard, the clamp 56 has a front face 58 that is generally vertical and parallel to the generally vertically aligned contact surface 54 so that rotation of a socket head cap screw 60 in the proper direction moves the clamp 56 toward the right as shown in the drawings, and will securely hold the knife 20 therebetween. More specifically, the cap screw 60 passes through an oversized aperture 62 in the clamp 56 and engages a tapped aperture 64 within the holding bar 32. The inside diameter of the aperture 62 is preferably oversized compared to the diameter of the shaft of the socket head cap screw 60 to permit horizontal as well as vertical movement of the clamp 56 relative to the cap screw 60, the position of which is percisely determined by virtue of its threaded engagement with the tapped aperture 64.

In accordance with another aspect of the present invention, the elevation or height of the cutting knife 20 can be easily and precisely adjusted for proper alignment and cooperative operation with the anvil head 13. The clamp 56 is provided with a relatively narrow shoulder 66 located below the front face 58 and is adapted to hold the bottom surface of the knife 20. The shoulder is narrower than the thickness of the knife so that the front face 58 of the clamp will force the knife toward and in contact with contact surface 54 of the bar to securely hold the knife when the screw 60 is tightened. It should be understood that the height of the cutting edge 36 of the knife 20 is therefore determined by the adjustment of the clamp 56 since the lower surface of the knife 20 rests upon the shoulder 66 of the clamp.

To adjust the elevation of the knife, the clamp 56 is provided with a pair of spaced apart socket head set screws 68 that engage tapped apertures 70 which extend completely through the height of the clamp as best shown in FIG. 4. By rotating the set screws 68, the elevation or height of the clamp and therefore the knife 20 can be varied as desired for proper operation. Since the aperture 62 in the clamp is oversized as previously mentioned, the clamp 56 may be moved vertically within reasonable limits. Moreover, the use of two set screws 68 located on opposite sides of the aperture 62, provide the additional adjustment of raising or lowering one end relative to the other which may be necessary to laterally align the knife edge.

Turning now to yet another important aspect of the present invention, the apparatus 18 is adapted to reduce shock to the knife edge during operation by cushioning the impact of the knife 20 if it strikes the anvil head 13. To provide the shock reducing capability, the adjacent surfaces 71 and 72 of the holding bar 32 and the block 26, respectively, which are immediately beneath the knife 20 have a resilient member 74 therebetween that is adapted to provide a cushioning effect and permit the downward deflection of the holding bar 32 which pivots around the set screw 42. The resilient member is shown to be of relatively flat circular shape which is located within a similarly configured recess 76 within the surface 72 of the block 26, although the recess could be located within the adjacent surface 71 of the holding bar if desired. The resilient member 74 is preferably fabricated of neoprane although other rubber or rubberlike materials may be used. The thickness of the member 74 is preferably such that it cannot escape the recess 76 with even maximum upward movement of the holding bar around the pivot 42. It is preferred that the resilient member 74 be generally centered beneath the entire length of the knife 20 and of a relatively large cross-sectional area. It is also preferred that it bears only against flat planar surfaces having no indentations or protrusions which would significantly increase wear upon the member and shorten its life expectancy through abrasion, uneven stressing, rubbing or the like.

From the foregoing it should be understood that an improved knife holding apparatus has been shown and described which employs a relatively few number of components, all of which can be inexpensively and easily manufactured.

Although various embodiments of the invention have been illustrated and described, they will suggest a number of variations and modifications to persons skilled in the art. Accordingly, the scope of the protection afforded this invention should not be limited by the particular embodiments shown and described, but should be determined by the terms of the definitions of the invention as are set forth in the appended claims and equivalents thereof.

Various features of the invention are set forth in the following claims.

Claims

I claim:

1. A knife holding apparatus for use with a slotting head mounted on a rotating shaft and cooperating anvil surface, said apparatus comprising:

a block having means for attachment to said cutting head;

a holding bar pivotally attached to said block and movable through a limited arc, said bar having generally vertical and horizontal contact surfaces at one end thereof, said vertical contact surface being adapted to cooperate in holding an elongated cutting knife, the cutting edge of which extends upwardly beyond the general surface of the bar and block;

said bar having a clamp means with a front face for holding the cutting knife against said vertical contact surface in secure engagement, said clamp means having a shoulder along the lower portion of said front face for engaging the bottom of said cutting knife, first means for adjusting the height of said clamp means relative to said horizontal contact surface of said holding bar, second means for selectively moving said clamp means toward and away from said vertical contact surface;

a resilient member positioned generally beneath the cutting knife between adjacent surfaces of said block and said holding bar for reducing shock to the cutting knife during a cutting operation.

2. Apparatus as defined in claim 1 wherein said holding bar includes a tongue means located at the end opposite said contact surfaces, said tongue means having an aperture therein for receiving pin means pivotally attaching said bar to said block, said aperture being located a predetermined distance from the end of said tongue means so that said tongue means engages said block in response to limited upward movement of said one end having said contact surfaces.

3. Apparatus as defined in claim 2 wherein said block has a recess in the upper surface thereof adapted to receive said tongue of said holding bar, and apertures located in the sidewall portions adjacent said recess for receiving pin means for pivotally attaching said holding bar to said block.

4. Apparatus as defined in claim 1 wherein one of said holding bar and block adjacent surfaces have a recess therein in which said resilient member is positioned, the thickness of said member being sufficient to prohibit said member from escaping from said recess when said holding bar is pivoted through the entirety of said limited arc.

5. Apparatus as defined in claim 4 wherein said resilient member is fabricated from neoprene.

6. Apparatus as defined in claim 4 wherein said resilient member comprises a generally flat circular shape and said recess is circular and has an inside diameter greater than the outer diameter of said circularly shaped member.

7. Apparatus as defined in claim 4 wherein said recess is located within the adjacent surface of said block and said thickness of said member is greater than the maximum upward travel of said pivotal holding bar relative to said block.

8. Apparatus as defined in claim 1 wherein said first adjusting means comprises a pair of spaced apart screw means positioned in respective apertures in said clamp means and adapted to vary the height of said clamp means relative to said horizontal contact surface in response to rotation thereof.

9. Apparatus as defined in claim 1 wherein said second means comprises an elongated screw means passing through an aperture in said clamp means and engaging a threaded aperture located within the generally vertical contact surface of said holding bar so that said clamp means is moved toward and away from said generally vertical contact surface, respectively, in response to rotation of said screw means in first and second directions.

10. Apparatus as defined in claim 1 wherein said shoulder is of a width less than the thickness of said cutting knife and is located a distance from the top of said clamp means that is less than the height of said knife said device is intended to hold.

11. Apparatus as defined in claim 1 wherein said block has a curved lower surface for cooperatively contacting the curved circumferential surface of the slotting head, and said means for attachment comprises a slot entending transversely therethrough adapted to receive a bolt for holding the same to the slotting head.