US2890749A - High speed toggle driver pivoted veneer clipper - Google Patents

Description

June 16, 1959 v. E. ANDERSON HIGH SPEED TOGGLE DRIVER PIVOTED VENEER CLIPPER Filed Oct. 10, 1955 5 Sheets-Sheet l ATTO/P/VE) June 16, 1959 v. E. ANDERSON 2,890,749

HI I GH SPEED TOGGLE DRIVER PIVOTED VENEER CLIPPER j Filed Oct. 10, 1955 s Sheets-Sheet 2 FIG. 2

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June 16, 1959 v. E. ANDERSON I 2,890,749

' HIGH SPEED TOGGLE DRIVER PIVOTED VENEER CLIPPER Filed Oct. 10, 1955 3 Sheets-Sheet 3 FIG. 4.

HTTOIP/VEV United States Patent HIGH SPEED TOGGLE DRIVER PIVOTED VENEER CLIPPER Victor E. Anderson, Springfield, reg., assignor to Clear Fir Products Co. Inc., Springfield, 0reg., a corporation of Oregon Application October 10, 1955, Serial No. 539,529 1 Claim. ((1164-43) The present invention relates to a high speed veneer "clipper and particularly to a novel anvil and knife combination adapted to effect efiicient and speedy clipping of continuously moving sheets of wood veneers into desired panel sizes. The invention is also adapted for the rapid cutting out of veneer defects.

Many veneer clippers have been proposed for cutting continuously moving sheets of wood veneers. Generally, they comprised means for rigidly supporting a veneer cutting station with means for delivering veneer sheets to said station, the station being comprised of an anvil and a knife assembly cooperable therewith. The knife was usually actuated vertically in guillotine-like fashion and was adapted to clip veneer supported beneath it on an :anvil, the knife contacting the surface of the anvil on 'the down stroke after cutting through the veneer. The down stroke of the knife blade had to be controlled very carefully so as to minimize impact of the knife edge with the anvil and to minimize knife wear. The anvil sup port Was considered important as it enabled the obtaining of a clean cut across the veneer substantially free from rips and tears. However, the combination had its disadvantages in that the knife would dull easily and had to be resharpened frequently, thus increasing down time. To overcome this ditiiculty, resilient anvils were proposed, for example anvils made of hard resilient rubber. This improvement, while it prolonged knife life somewhat, actually merely shifted the problem to the anvil which required maintenance as the knife would cut the rubber with the net result that the anvil eventually had to be replaced. Even then the knife did not always maintain a sharp edge.

The use of a vertically moving knife also had its disadvantages in that it required high vertical side supports, for example slide or roll guiding supports to control the up and down movement of the knife, which necessitated considerable head room. For best cutting performance, the knife required heavy, massive back-up means which had to be moved bodily with the knife.

Such machines, because of their high center of gravity, were subject to vibration and were noisy. Furthermore, the machines were not as quick acting as desired because of the inertia prevailing in the heavy back-up means and in the mechanism operating the vertically sliding knife associated with the back-up means. Long operating strokes had to he used in order to oscillate the knife up and down because of the considerable weight of the knife assembly.

The present invention differs from prior veneer clippers in that it provides for a novel arrangement of the anvil and clipper assembly resulting in considerable saving in head room. The machine, while it has a heavy knife assembly, has a low center of gravity and operates with minimum vibration and noise.

The invention provides an entirely difierent type of knife arrangement at the cutting station where a pivotally mounted carriage is employed to carry the knife which rocks by the axial turning or oscillation, clockice wise or counterclockwise, of a massive longitudinal member which acts as a stable pivot point, the center of gravity of the carriage being maintained near the pivot so that the rocking of the carriage is effected easily, quietly and quickly. By so balancing the knife assembly, the carriage, which responds easily to an applied rocking force, enables the knife to cut at speeds of up to about 500 oscillations per minute with minimum vibration, a speed not generally approached by prior clippers. In other words, the heavy and rigid knife assembly is not displaced bodily as in prior clippers but, on the contrary, is rocked, with the weight of the assembly substantially balanced about the pivot.

The rockable carriage construction enables the use of a heavy rigid knife that does not spring out of line when contacting a veneer sheet during cutting. Furthermore, the heavy rigid knife blade insures a clean cut and has a long tool life.

The knife blade is situated on the carriage so that its longitudinal axis is substantially parallel to the longitudinal axis of the massive member about which it pivots. This arrangement enables sensitive and accurate control of the knife, whereby it can be easily brought down into cutting relationship with the anvil without striking it with any substantial force and in many instances hardly striking it at all. However, it is preferred that a cutting edge of the knife be brought down closely adjacent and slightly past an edge of the anvil for efii- -cient cutting. This type of cutting or shearing affords optimum tool life for both the anvil and the knife, since neither hardly touches the other during cutting in this embodiment of the combination. The rocking increment is small and enables the knife to be retracted quickly for the next cut.

These and other features will more clearly appear when taken in conjunction with the attached drawing in which:

Fig. l is a plan view showing the pertinent portions of the veneer clipping machine with the knife of the clipper in a lowered position.

Fig. 2 shows a fragmentary side elevation view of the mechanism which operates the knife carriage;

Fig. 3 depicts a fragmentary side elevation taken along line 33 of Fig. 1 showing an embodiment of the knife and anvil combination making up the veneer cutting station with the knife of the clipper in a raised position;

Fig. 4 which is similar to Fig. 3 shows another embodiment of the veneer cutting station comprising the knife and anvil combination;

Fig. 5 is an enlarged cross-sectional View showing a substantially square edge type of knife blade; and

Fig. 6 shows another anvil and knife combination.

Referring to Figs. 1, 2 and 3, 1L and 1R are side frame means comprised of steel plates having structural transverse members not shown for maintaining the frame rigid and to enable the veneer cutting station comprising anvil 2 and knife carriage 3 with knife blade 4 to be suitably supported, the neck 2a of the anvil being held rigidly in channel 5 by adjustable bolts 6 and 7, the channel in turn being adjustably bolted to I-beam 8 adequately supported by a foundation, also not shown;

Fig. l which is a plan view of the clipper shows a plurality of parallel pulley driven belts, for example 9 and 10 on pulleys 9a and 10a, on a suitably driven rotatable shaft 11, adapted to deliver veneer sheets to the cutting station, and another set of parallel belts, for example 12 and 13 going around pulleys 12a and 13a mounted on rotatable shaft 14, adapted to carry cut sheets away from said station. Generally, four belts side by side are employed on each side of the station to deliver and carry the veneer sheets to and from it. The veneer travels through the machine in a substantially straight line.

a J Knife carriage 3 is constructed of heavy thick-walled cylindrical sleeve 15 which supports the knife blade about oseillatable stub shafts 16L and 16R via a pinrality of transverse structural' 'arm members 17, the arms extending fromjthe'carriage "sleeve to points next to but above the'anvil as shown inFig. 3. The sleeve is fitted and keyed'to the stub shafts'at theirreduced end portions. At the'end of the arms 17, transverse member '18 'is provided to rigidize the carriage via stiffening 'Webs 20 as shown. As can'be seen in Fig. 3,'knife 4 is'secured in a proper position on the carriage by means of bolts which enable the knife to be moved to adjusted positions on the carriage.

Arms 17 extend between'the knife and sleeve 15 and are substantially parallel to the line of travel'of the veneer. The axis of rotation of sleeve 15 is only slightly above the line of travel of the veneer'and substantially closer to the plane of said veneer than to a vertical plane passed through the knife. in i The sleeve of the carriage has a strong back 22 which serves to further stiffen the assembly, to stablize the movement of the carriage and keep it substantially in balance as it is rocked by oscillating stub ' shafts 16L and 16R. Member 22 is substantially coplanar with the axis of sleeve 15 and acts as a counterweight for the knife and carriage. The counterweight is fastened to the opposite side of sleeve 15 from the knife and is elongated in the horizontal direction so as to lie completely within the confines of frame members 1L and IR. It will be seen that no additional head room is required 'by this construction. The stub shafts may have adiameter ranging from about 2 /2 to 3 inches or more. The weight of the cylindrical'sleeve 15 together with 'the strong back of the carriage maintains the center of gravityof the knife carriage as near as possible to the stub shafts and the sleeve, thus making the carriage easy to rock and control.

The stub shafts are oscillated by means of double acting compressed air or steam cylinders23L and 23R.

These'are rigidly attached to side frameslL and 1R (Figs. 1 and 2) with piston rods 24L and 24R for the cylinders attached to link connectors or crank pins 25L and 25R which in turn are pivotally connected toa toggle joint mechanism which'actuates the knife carriage.

The toggle joint mechanism includes two sets of paired,

upper toggle links indicated at 26L and 26R, respectively, and as shown more clearly in Fig. 2, two sets of paired lower toggle links, comprised of toggle link set 27L and 'a corresponding set of toggle links 'on the other side of the machine. The toggle structure on only one 'side' of the machine is discussed, since the actuating elements on the other side are the same. Thus, the set of'toggle links 26L is pivotally connected to hell crank 28L which is keyed to oscillatable stub shaft 16L at 29L. Toggle link set 27L is pivotally connected to toggle anchor 30L. When piston rod 24L is caused to move towards the toggle links so as to align them substantially vertically, the bell crank moves counterclockwise in a direction to oscillate stub shaft "16L, which causes the carriage via the keyed sleeve 15 to rock in the same direction to bring knife blade 4 in cooperable relation with the anvil, as shown by the dotted lines in Fig. 3.

Cylinder 23L is operated by air or high pressure steam passing through pipe connections 31L and directed by T-connection 32L to suitably operated controlvalves 33L and 34L, for example solenoid controlled valves, then through hose connections 35L,"36L to either- 'side of the cylinder. A similar arrangement employed for cylinder 23R. The control valves arejiop erated by switch means not shown to effect the change in direction of the pistons. Gene rally means cooperating with the movement of the knife are provided to reverse automatically the direction of the piston rods after a cut has been made,

or if desired automatic means may be providedtorock the knife carriage in timed sequence to the travel of the veneer in accordance with the size of the panel to be cut. In other words, the veneer clipper may be made to operate manually or automatically or both.

The clipper provided by the invention has the advantage over prior art types in that it can be actuated by a small piston stroke. Foryexample, in the embodiment of Fig. 2, piston rod 24L can be operated at a stroke 'of' fo'ur 'inches iris'tead" of six inches as-previously required, thereby 'efie ctingao'ne-third increase in speed, other things-being equal. A'further increase in "speed is effected by making the distance-from the 'togglepivot connection of crank pin 25L to the center ofstub shaft 16L one-half of that from the center ofstub shaft 16L to th'e'c'utting edgeofthe knife,thus effecting double increase in speed. As an example,-the first distance may be 5" and the second 10". If desired, the speed ratio could be 1 /2 to l or 3 to 1 or even higher. It is to 'be appreciated that the foregoingexamples are by-way of'illustration and are not to be construed to limit the invention.

iAn enlarged view of'an embodiment of the knife '4 andganvilcombination is shown in Fig. 5. The knife 4, which is generally referred to as having a square cornered edge, usually has a back draft or clearance angle to enable it to move freely past and just below the top of anvil 2. Aclearance angle of about 3 isadequate although the angle mayran'ge up to about 5 or even- 10. The sides 2b and 2c of the anvil have a slight taper, the sides converging as they extend downwardly in Fig. 5.

In Fig.6, an embodimentof a knife and anvil combination is shown in whichknife blade 4 has attached to it near the top by bolt 38 a resilient means, for ex- .ample a leaf spring 39 with a roller 40 mounted at its free end, which is adapted to contact veneer sheet 37 on the anvil before the knife reaches its cutting position so as to flatten the sheet and hold it against the anvil in order to' further improve the cutting. 'Generally, the ,same'thing is accomplished by having a plurality of fingers spaced across the machine just before the sheet reaches the anvil so as to keep the sheet flat and in position for cutting. While the flow of portionsof a veneer sheet occupying the cutting station is stopped at the instant of cutting by the'knife blade, the moving sheet is cut so quickly that the remaining portions of the sheet 'outside the cutting stationare hardly affected other than by showing a very slight ripple.

The anvil and the knife blade may be made of high alloy tool steel, for example high speed steel. In the construction of the invention these parts have an improved life and do not require as much maintenance as prior construction. I

'As shown in Figs. 3 and 4, veneer cutting may be effected in two preferred ways. Thus, in Fig. 3 the square edge type of knife blade provides a nipping or shear type action adjacent the trailing edge of the anvil, i.e. the edge opposite the leading edge that the veneer sheet crosses first on the anvil. In Fig. 4 the knife is sharply'pointed and may be used to cooperate with the leading'edge of the 'anvil, although the knife blade may also be used to cooperate with the trailing edge.

As hasbeen' stated hereinbefore, the advantages of the -machine are in its ease of handling and compactness, thusrequiring little head room. If desired one or more machines can be placed one on top of the other to double or even triple the production rate in the same area'nor- *mally' occupied by a prior machine requiring a lot of "head room. I

The expression veneerclipper as employed herein is meant to define generically a clipping device for cutting-'fiat sheet-Iike materials such as wood and-other products, for example hard card board, metal-sheets,

' etc.

'Whilethe present invention has been described in con- -'junction withpreferred-embodiments, it is to be understood that modifications-and variations-may" be resorted to without departing'from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and the appended claim.

I claim:

A veneer clipper comprising a frame, conveyor means mounted on said frame for transporting veneer continuously thru the clipper along a substantially horizontal path, a horizontal anvil member immovably fixed on the frame and mounted next to and below the path of travel of veneer thru the clipper and extending transversely of said path of travel, elongated shaft means rotatable about its longitudinal axis mounted on said frame next to and above the path of travel thru the clipper, said shaft means extending substantially parallel to said anvil membe: but being offset to one side thereof, a knife parallel to said anvil member connected to said shaft means extending on one side thereof and above said anvil member in cooperative cutting relationship therewith, a counter weight positioned above the path of travel of veneer and fastened to said shaft means on the opposite side thereof from said knife, a reciprocating two-stroke motor means for actuating said shaft means, a stub shaft mounted on the end of said shaft means for rotation therewith, a set of toggle links attached at the jointed end to said motor means, a crank attached to said stub shaft at one end and to one of said toggle links at the other end, the other of said toggle links being connected to said frame, whereby one stroke of said motor means is operable to rotate said shaft means first in one direction and then the other with said knife moving downwardly toward and then returning from said anvil member.

References Cited in the file of this patent UNITED STATES PATENTS Re. 19,989 Swift May 26, 1936 672,526 Hunter Apr. 23, 1901 944,555 Holden Dec. 28, 1909 947,744 Stohr Jan. 25, 1910 1,262,189 Froehlich Apr. 9, 1918 1,359,058 Haase Nov. 16, 1920 1,500,600 Biggert July 8, 1924 1,501,653 Fine July 15, 1924 1,767,763 Johnson June 24, 1930 1,798,106 Pels Mar. 24, 1931 1,918,318 Biggert July 18, 1933 1,988,215 Peterson Jan. 15, 1935 2,047,322 Hazelton July 14, 1936 2,130,473 Ruau Sept. 20, 1938 2,348,491 OMalley May 4, 1944 2,532,739 Slusher Dec. 5, 1950 2,598,721 Porter June 3, 1952 2,621,736 Scruggs Dec .16, 1952 2,623,587 Hervey Dec. 30, 1952

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