US3703117A

US3703117A - Rotary paper-cutter knife structure

Info

Publication number: US3703117A
Authority: US
Inventors: Merton Louis Matthews
Original assignee: Maxson Automatic Machinery Co
Current assignee: Maxson Automatic Machinery Co
Priority date: 1970-12-01
Filing date: 1970-12-01
Publication date: 1972-11-21
Anticipated expiration: 1989-11-21

Abstract

A rotary paper-cutter knife structure the knife blade of which is secured in a trough of a knife holder in the form of the revolver of a conventional paper-cutter machine. The knife is radially adjustable by means of a pusher having a ledge contacting the heel surface of the knife and having screw means extending therethrough and engaging the bottom surface of the trough. The knife blade is releasably clamped in the trough by means of wedges.

Description

United States Patent Matthews 1 Nov. 21, 1972 [54] ROTARY PAPER-CUTTER KNIFE 2,751,006 6/1956 Lane ..83/674 STRUCTURE 2,735,488 2/1956 Anderson et al ..83/677 X 3,321,145 5/1967 Gorman- ..83/349 X [72] Invent gf' 3,322,012 5/1967 Murray ..83/345 x 2,270,639 l/l942 Parks, Jr ..83/677 [73] Assignee: Maxsou Automatic Machinery Company, Westerly, R I Primary ExaminerJames M. Meister Filed Dec 1 1970 Attorney-Rines and Rines [21] Appl. No.2 93,978 [5 ABSTRACT A rotary paper-cutter knife structure the knife blade 52 us. C1 ..83/677, 83/700 of which is Secured in a trough of a knife holder in the I511 1nt.C1. ..B23d 25/12 form of the revolver of a conventional Paper-cutter 5s Field of Search ..83/677 674 345-348 machine- The knife is radially adjustable by means 85/698406 a pusher having a ledge contacting the heel surface of the knife and having screw means extending therethrough and engaging the bottom surface of the [56] References cued trough. The knife blade is releasably clamped in the UNITED STATES PATENTS trough y means of Wedges- 2,660,242 1 1/ 1953 Lane ..83/674 6 Claims, 3 Drawing Figures P'A'TE'N'TEDnnv 21 1912 3, 7.03 1

t] 3 INVENTOR.

Merton Lou/s Matthews Attorneys ROTARY PAPER-CUTTER KNIFE STRUCTURE BACKGROUND OF THE INVENTION.

1. Field of the Invention The invention is in the field represented by the conventional rotary paper-cutter industry.

2. Description Of The Prior Art.

In paper cutters of this type, the knife blade is customarily held in place by bolts passing through holes 1 in the blade. These blades normally have arrangements by which they can be adjusted for positioning of the cutting edge through push or pull screws or a combination of push and pull screws. The push and pull screws may work on the blade itself or on a carrying bar to which the blade is bolted.

The method of securing the cutting blade to the revolver with bolts results in a number of undesirable effects, the most obvious and common of which is an increase in difficulty of setting the knife resulting from localized force vectors of varying directions set up in the blade by the holding bolts.

A second disadvantage occurs when blades are sharpened. If they are not held in a fixture which duplicates the holding bolt locations of the actual revolver, a wave edge may result when the blade is secured by these bolts and this must be overcome through manipulation of the push-pull screws.

A third problem occurs during operation. The vibrations and shocks resulting from cutting loads tend to loosen or tighten the holding bolts changing the localized force vectors surrounding these bolts and causing the blade to creep or lose its setting.

Another disadvantage results from the fixed position of the adjusting screws along the length of the blade; because of this overcorrection and excessive honing is often necessary if a minor nick occurs at a point where the adjusting screws happen to have least effect because of location.

An object of the present invention is to improve upon the mounting of knives of the above-described character.

A further object is to provide a knife structure that shall eliminate the need for the use of the holes and bolt-head seats in the knife blade and of the bolts that are mounted in those holes.

Another object is to provide a new and improved knife structure of the above-described character the knife blade of which shall be effectively wedge-locked against accidental removal from the revolver upon which it is mounted.

Still another object is to provide new and improved means for adjusting the knife blade on the revolver upon which it is mounted.

Other and further objects will be explained hereinafter and will be particularly pointed out in the appended claims.

SUMMARY OF THE INVENTION According to the invention, the knife blade is mounted in a small, longitudinally extending trough provided in the surface of the revolver of the machine. The knife blade is adjustably supported in the trough by pusher-part supports disposed adjacent to the bottom surface of the trough. Accidental removal of the blade from its trough is prevented preferably by means of a wedge lock.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in connection with the accompanying drawings, in which FIG. 1 is a diagrammatic elevation of a revolver cylinder upon which a knife blade is mounted according to a preferred embodiment of the present invention; and

FIGS. 2 and 3 are sections taken upon the respective 0 lines 2-2 and 33 of FIG. 1, upon a larger scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION A small knife-receiving trough 2 is shown provided in the surface of a knife-blade holder, shown as a cylindrical revolver 4 of the above-described type. The trough 2 may be constructed in any desired manner, as by milling of the conventional type. Though the revolver 4 is shown provided with only a single trough 2, it will be understood that the revolver may be provided with several such troughs 2, each receiving a knife.

The dimensions of the trough 2 will vary with the dimensions of the knife blade 5 that is to be received therein. Troughs 2 of dimensions three-fourths inch wide by three-fourths inch deep or 1 inch wide X 1 inch deep have been used successfully,'but much smaller or larger troughs may also be used.

Though the trough 2 is shown diagrammatically extending longitudinally of the cylinder of the revolver, it is usually cut on a true helix angle; as the cutter that mills the trough moves along linearly and uniformly, the revolver is uniformly rotated around its axis, the two movements being in constant fixed ratio. By reason of this method of cutting the trough, the blade 5 produces a common-type shear cut.

The trough 2 is provided with a bottom-wall surface 6 and two oppositely disposed radial, but substantially parallel, side-

wall surfaces

8 and 10, substantially perpendicular to the bottom wall surface 6.

The

side wall surfaces

8 and 10, as will hereinafter be more fully explained, need not, however, have this precise configuration; but, if they do, the oppositely disposed front and

back surfaces

14 and 16 of the knife blade 5 are tapered with respect to each other, as shown. The back side surface 16, for example, may be ground at an angle to the front side surface 14 of between 2% and 7, but this angle is not critical, and angles of 15 and 20 are permissible. Larger and smaller angles may also be used. The width of the bottom heel surface 34 of the knife 5 may be selected as desired; widths of three-sixteenths inch and five-sixteenths inch have been used with excellent results. The thickness of the heel and the angle of taper is determined, not by a demand of strength or rigidity of the blade but, rather, by the amount of clearance demanded between the revolver body 4 and the cutting edge of the blade 5. This clearance is usually determined by the type of material being sheeted. Clearances of one-eighth inch to three-fourths inch have been used successfully and greater or lesser clearances are feasible. The choice of cutting clearance angle from the cutting edge to the back side surface 16 of the knife will depend on the material to be cut.

The blade 5 may be constituted of high-speed steel with a hardness of 60-62 on Rockwell C Scale, but softer or harder blades of the same or different material are also suitable.

The knife 5 is shown secured in the trough 2 by means of a plurality of clamps 20. These clamps may be made of any desired material, such as a tough hardenable steel, or even normal cold rolled steel with no subsequent heat treatment.

The front side surface of this clamp' 20 is shown ground to the same angle as that of the back side surface 16 of the knife, in order to enable these surfaces to be mounted in contact with each other.

ln the preferred embodiment of the invention, as illustrated, the clamp 20 is constituted of one arm of a bifurcated resilient U-shaped member the other arm of which is shown at 22.

It is not essential, however, that the

arms

20 and 22 be made in one piece.

Separate arms

20 and 22, not shown, may be used with equal effectiveness, though they naturally lack the resiliency provided by the small neck 7 of the U.

The U-shaped member comprising the

arms

20 and 22 is provided with a centrally disposed countersunk threaded cylindrical opening 24 for receiving a correspondingly shaped clamp-expander screw 26. By the

arms

20 and 22 becomingthuspressed away from each other, the knife blade 5 becomes wedge-locked against the surface 6 of the trough.

The invention may, however, be practiced without the wedging effect produced by tapering the contacting surfaces of the knife blade 5 and the clamp 20. Enough side thrust can be generated by the described locking expansion even if these contactingsurfaces of the knife blade 5 and the clamp 20 are untapered. There is a remote possibility, however, with such untapered surfaces, that the blade might accidentally fly out of the trough if, for some reason, the expanding screw 26 should become loose. The tapered faces provide insurancc against this type of possible accident.

lt will also be understood that, even where the tapering is employed, the knife 5 may be untapered, and the taper may be provided, instead, upon one of the side surfaces 6 and 8 of the trough 2. In all these cases, the knife blade 5 will become wedge-locked in the trough 2 by reason of the fact that portions of the clamp 20 and the knife surface contacting therewith are tapered with respect to one or both of the

trough side surfaces

10 and 8 in order to wedge-lock the knife 5 in the trough 2.

The invention provides also for adjusting the position of the knife blade 5 in the trough 2. To the attainment of this end, a plurality of pusher-part knife supports 30 are disposed in the trough 2 adjacent to the bottom surface 6 thereof. The pusher-part supports 30 may be adjusted up and down in the trough 2, away from and toward the bottom wall surface 6, by adjustment of set screws 32. The heel 34 of the knife blade 5 contacts with projecting knife-supporting ledges 36 of the pusher-part supports 30. Adjustment of these pusherpart supports 30, therefore, will effect correspondingadjustment of the blade 5, toward and from the bottom wall 6 of the trough 2.

The pusher-part supports 30 are shown as alternating with, or intercalated between, the clamps 20, in wide spaces between the clamps, to enable wide lateral adjustment of the pushenpart supports. Closer and wider spacings of the pusher-part supports have been used with satisfactory results. Some of the advantages of the invention are:

A. A minimum amount of metal needs to be removed from the revolver, which affords the following advantages:

Maximum strength and rigidity of revolver for a given diameter. The entire circumference of the revolver can b machined smooth for optimum aerodynamic design, and the use of covers or fill-in pieces is not necessary.

. Simplicity and ease of machining the revolver. The ease with which a multi-bladed revolver can be fabricated even with small-diameter revolvers. The entire knife mounting requires so little length of arc of circumference that many holding troughs can be machined into a single revolver.

. Base with which a multi shear angle revolver can B. Knife is easier to install and adjust because of the following: I

Knife is seated or wedged against a surface machined true to axis of revolver. The only movement possible is in one plane at to revolver axis.

. Knife blade can be of small cross section as rigidity may be obtained from method of mounting thereby making it easier to deflect to conform to helix angle and requiring less force to deflect it for setting.

. Adjustment pushers shown on print can be moved parallel to axis of revolver between clamps allowing technician setting blade to obtain movement at position desired.

. Knife does not tend to walk or move during final tightening action. I

. Adjustment of one point in blade does not cause movement at a different point further along the blade. A knife blade, constructed and mounted as above described, need not be itself rigid, it becomes inherently endowed with rigidity and stability.

C. Knife maintains set and sharpness longer requiring fewer adjustments because:

. Method of mounting allows maximum rigidity of revolver for a given revolver diameter, reducing vibration which destroys edge.

. Greater rigidity results in less deflection under cutting load.

. Because of the wedge locking action unit does,

holding bolts do not tend to loosen under impact loading allowing blade to walk" out of setting.

D. Because the cutting edge of the blade is wedged against the milled trough the cut line must be as straight and true as the slot itself and providing the slot is true and bed or stationary knife are true it is impossible to set the knife in such a manner that a concave or convex cut line is obtained.

E. If the slot is machined true it is impossible to vary the front rake" or clearance angle through improper setting and knife loading will thereby remain constant through entire length of cut.

F. Knife is safer to operate at higher speeds. Because of the wedge angles it is impossible for the knife to move outward through centrifical force. The possibility of hooking the blade against the bedknife blade is lessened.

G. With this type of knife mounting it is feasible to increase shear angle of knife trough to the point that a diagonal cut is obtained.

Further modifications will occur to persons skilled in the art and all such are considered to fall within the spirit and scope of the present invention, as defined in the appended claims.

lclaim:

1. A knife structure comprising a knife holder having a trough provided with a bottom surface and two side surfaces, a pusher-part knife support disposed in the trough and having a ledge adjacent to the bottom surface, a knife in the trough having a heel surface contacting with the ledge of the pusher-part support to support the knife in the trough, the pusher-part support having screw means extending therethrough and engaging the bottom surface of the trough for adjusting said ledge toward and from the bottom surface of the trough to provide for corresponding adjustment of the heel surface in contact with said ledge, and clamp means for pressing said knife against one side surface of the trough to secure the knife in the trough 2. A knife structure comprising a cylindrical revolver having a trough provided with a bottom surface and two side surfaces extending longitudinally of the cylinder, a pusher-part knife support disposed in the trough and having a ledge adjacent to the bottom surface, a knife having a heel surface contacting with the ledge of the pusher-part support to support the knife in the trough and two side surfaces one of which contacts with one of the trough side surfaces, the pusher-part support having screw means extending therethrough and engaging the bottom surface of the trough for adjusting said ledge toward and from the bottom surface of the trough to provide for corresponding adjustment of the heel surface in contact with said ledge, a clamp in the trough having two oppositely disposed surfaces one of which contacts with the other knife surface, and means engaging the other oppositely disposed surface of the clamp to secure the clamp in the trough in order to secure the knife in the trough.

3. A knife structure comprising a cylindrical revolver having a trough provided with a bottom surface and two side surfaces extending longitudinally of the cylinder, a plurality of pusher-part knife supports disposed in the trough and each having a ledge adjacent to the bottom surface, a knife having a heel surface contacting with the ledges of the pusher-part supports to support the knife in the trough and two side surfaces one of which contacts with one of the trough side surfaces, the pusher-part supports having screw means extending therethrough and engaging the bottom surface of the trough for adjusting said ledges toward and from the bottom surface of the trough to provide for corresponding adjustment of the portions of the heel surface contacting therewith, a plurality of clamps in the trough each having two oppositely disposed surfaces one of which contacts with the other knife side surface, and means engaging the other oppositely disposed side surfaces of the clamps to secure the clamps in the trough in order to secure the knife in the trough, the said one surface of the clamps and the portion of the knife side surface in contact therewith being tapered with respect to one of the trough side surfaces in order to wedge the knife in the trough.

4. A knife structure as defined in claim 3 in which the pusher-part knife supports are separate from the clamps and are laterally adjustable in the trough.

5. A knife structure as defined in claim 1 in which the pusher-part knife support is separate from the clamp means and laterally adjustable in the trough.

6. A knife structure as defined in claim 2 in which the pusher-part knife support is separate from the clamp and is laterally adjustable in the trough.

Claims

1. A knife structure comprising a knife holder having a trough provided with a bottom surface and two side surfaces, a pusher-part knife support disposed in the trough and having a ledge adjacent to the bottom surface, a knife in the trough having a heel surface contacting with the ledge of the pusher-part support to support the knife in the trough, the pusher-part support having screw means extending therethrough and engaging the bottom surface of the trough for adjusting said ledge toward and from the bottom surface of the trough to provide for corresponding adjustment of the heel surface in contact with said ledge, and clamp means for pressing said knife against one side surface of the trough to secure the knife in the trough .

1. A knife structure comprising a knife holder having a trough provided with a bottom surface and two side surfaces, a pusherpart knife support disposed in the trough and having a ledge adjacent to the bottom surface, a knife in the trough having a heel surface contacting with the ledge of the pusher-part support to support the knife in the trough, the pusher-part support having screw means extending therethrough and engaging the bottom surface of the trough for adjusting said ledge toward and from the bottom surface of the trough to provide for corresponding adjustment of the heel surface in contact with said ledge, and clamp means for pressing said knife against one side surface of the trough to secure the knife in the trough .

2. A knife structure comprising a cylindrical revolver having a trough provided with a bottom surface and two side surfaces extending longitudinally of the cylinder, a pusher-part knife support disposed in the trough and having a ledge adjacent to the bottom surface, a knife having a heel surface contacting with the ledge of the pusher-part support to support the knife in the trough and two side surfaces one of which contacts with one of the trough side surfaces, the pusher-part support having screw means extending therethrough and engaging the bottom surface of the trough for adjusting said ledge toward and from the bottom surface of the trough to provide for corresponding adjustment of the heel surface in contact with said ledge, a clamp in the trough having two oppositely disposed surfaces one of which contacts with the other knife surface, and means engaging the other opposiTely disposed surface of the clamp to secure the clamp in the trough in order to secure the knife in the trough.