Lumber trim end chipper

An improved method and apparatus which cuts certain wood pieces, commonly referenced as &#8220;mill ends,&#8221; such that the chips can be used to make paper, cardboard and other recyclable materials. The use of a horizontal drum in combination with a horizontal anvil and a &#8220;moving cavity&#8221; which orients elongate elements, is likewise contemplated.

TECHNICAL FIELD

The present invention generally relates towards wood processing, and particularly relates to a method and apparatus for reducing mill ends (a.k.a. trim ends ) such as those provided by dimensional lumber processing.

BACKGROUND OF THE INVENTION

Lumber mills trim lumber to exact lengths, and trim out undesirable portions such as knots and other imperfections so as to improve the grade of lumber. The trim ends can be of various sizes, but typically includes various lengths of 2 4s, 2 6s, 2 8s, 2 12, 4 4s, 4 6s, etc. There is a need for a machine to reduce such trim ends to the proper size. Many different machines have been tried such as disc chippers, hogs, drum chippers, etc, with very little success. Therefore, improvements are needed.

SUMMARY OF THE INVENTION

The present invention overcomes deficiences in the prior art by providing an improved method and apparatus which cuts certain wood pieces, known as mill ends , such that the chips can be used to make paper, cardboard, and other recyclable materials.

Therefore, it is an object of the present invention to provide an improved wood processing apparatus.

It is a further object of the present invention to provide an improved wood processing method.

It is a further object of the present invention to provide an improved method of processing wood members which is efficient in operation.

It is a further object of the present invention to provide an improved method of processing wood members which is simple in operation.

It is a further object of the present invention to provide an improved method of processing wood members which is effective in providing proper chip size.

It is a further object of the present invention to provide an improved apparatus for processing wood members which is efficient in operation.

It is a further object of the present invention to provide an improved apparatus for processing wood members which is simple in operation.

It is a further object of the present invention to provide an improved apparatus for processing wood members which is effective in providing proper chip size.

It is a further object of the present invention to provide an improved apparatus for processing wood members which is effective in recovering a maximum of proper size chips and thus reduces waste.

Other objects, features, and advantages of the present invention will become apparent upon reading the following detailed description of the preferred embodiment of the invention when taken in conjunction with the drawing and the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made to the drawings, in which like numerals indicate like elements throughout the several views.

The purpose of the machine described is to cut the mill ends into smaller chips. The resulting smaller chips can then be used to make paper, cardboard and other recyclable material.

General Construction and Operation

Generally described, the apparatus 10 according to the present invention is configured to process lumber mill ends 5 , and includes the following elements:

rotating cutting drum 20

reciprocating top plate 40

Such mill ends 5 are dropped into the top of the apparatus and are consumed by the rotating drum 20 having knives thereon. One important feature of the invention is the preferred orientation of the mill ends relative the drum during the cutting process.

Reference will now be made FIGS. 1-4 .

FIG. 1 is a side elevational, illustrative, view of a rotating drum according to the present invention, configured to process lumber wood mill ends by use of a reciprocating top plate which is positioned above a reciprocating plunger. The plunger reciprocates along a generally horizontal linear path, and pushes the wood mill ends (a.k.a. wood trim ) into contact with the rotating drum, which works in combination with the anvil to process the wood mill ends in a particular manner.

FIGS. 2A-2F are sequential views of a process according to the present invention.

In FIG. 2A , the reciprocating plunger 30 is shown retracting with the top plate providing an aligning feature. This aligning feature is provided by the interaction of the wood members with the top plate; as the plunger 30 retracts, eventually wood positioned atop the reciprocating plunger 30 will contact the reciprocating top plate 40 . As the reciprocating plunger 30 continues to retract, the wood 5 thereon will tend to slide on the top of the plunger, as the wood is pushed against the leading, vertical, face of the reciprocating top plate 40 .

FIG. 2B illustrates the reciprocating plunger 30 being fully retracted, with the mill ends falling down from a top of the upper surface of the plunger 30 . Preferably, some alignment has been provided by the reciprocating top plate 40 due to the 5 previous step, so the moving cavity can maintain the wood member 5 in a desired orientation.

FIG. 2C illustrates the reciprocating plunger 30 and the reciprocating top plate 40 moving in tandem towards the rotating cutting drum 20 . This could be known as a moving cavity .

In FIG. 2D , the top plate is shown fully extended, and the reciprocating plunger 30 is still extending, with the wood being processed by the knives on the rotating cutting drum 20 .

In FIG. 2E , the reciprocating plunger 30 stroke is complete, and the wood member 5 has been essentially consumed from within the moving cavity.

In FIG. 2F , the reciprocating top plate 40 is shown in its retracted configuration. At this point the reciprocating plunger 30 may be withdrawn. It may also be understood that wood mill ends 5 which fall atop the upper surface of the top plate 40 may be aligned against stationary member 7 (which could be a hopper wall) similar to that shown in FIG. 2 A. It should also be noted that alignment will occur during the retracting of the plunger (and/or the cover plate) as well as during the out stroke of the various members.

FIG. 3 is a close-up illustrative view of the anvil 50 , shown in association with the rotating cutting drum 20 and the other previously-discussed members. In one preferred embodiment the anvil will define a straight edge spaced approximately one-half inch from the drum surface, with the cutting elements extending just less (within acceptable tolerances) than that distance from the surface of the drum.

As may be understood, as the corner 1 becomes worn down by the cutting action, corners 2 , 3 , and 4 may be used by remounting the anvil 50 within the frame of the apparatus.

The reciprocating plunger 30 can be set upon bearings such as known in the art, including Nylatron bearing surfaces.

FIGS. 4A-4C are various views of one type of knife which may be used under the present invention. FIG. 4A shows the right side of the knife 21 . FIG. 4B shows the front side of the knife 21 and FIG. 4C shows the top of the knife 21 .

The knife 21 defines three cutting edges; a main cutting edge 22 and two side cutting edges defined by two corresponding cutting wings 21 W. The two cutting wings define faces 21 F, and one other face is defined by the main body of the knife. All of the cutting edges are defined by approximately 30 degree angles. The main cutting edge 22 cuts along the grain such that it effectively slices the wood fibers apart. The side cutting edges extend from the main cutting edges at approximately 45 degree angles, for effective cutting at 45 degrees across the wood grain. If desired, optional serrations may be provided such as 25 to provide additional breakup of the wood fibers.

Multiple knives 21 are positioned on the drum in spiral or other known overlapping configurations, such that during the initial cut, the three cutting edges enter a horizontal wood surface substantially simultaneously.

The Cutting Action and Orientation

Preferably, the orientation is such that the grain of the mill ends (at least the generally elongate ones) will be substantially aligned with the horizontal rotational axis of the cutting drum.

The rotating cutting drum 20 includes a plurality of spiral mounted knives thereon, which provide a cutting action which extends across the length of the drum.

Under one embodiment of the present invention, a 50-inch diameter drum at 300 RPM provides 3,926 FPM of knife speed. At 250 RPM the knife speed would be 3,272 FPM. This slower knife speed is very important to obtain a smoother cut and not shatter or fracture the chips.

At this much slower knife speed, combined with the configuration of the 30 defined cutting edges and the cutting wings on the knives slicing the fibers at 45 and the sharp cutting surface of the top of the knife cutting along the length of the fiber, the controlled feed rate of the moving cavity will then produce a very precise wood chip with very little waste in fines or overs.

Various alternatives are contemplated, including the use of two lungers , one atop the other, with the lower plunger being less thick than other, but both including the leading curved surface. The lower plunger could be 6-8 inches thick and contemplated for use in processing smaller wood objects. The upper plunger could be larger (e.g., 18-24 inches thick, and could be used to process larger wood objects such as log cut-offs. Control of the two plungers could be independent, in that the lower plunger could be fully extended to act as a floor for the larger upper plunger to work off of.

Alternatively, the larger plunger could be allowed to frictionally slide relative to the lower plunger, with fictional engagement providing the following operational sequence. As the two plungers extend, eventually the upper (thicker) plunger will reach its limit and will be stopped thereby by a stop. The lower (thinner) plunger will continue to move out to its limit. The lower plunger will then be retracted, with the upper plunger being retracted therewith by fictional engagement. However, the top plunger will be stopped by a stop when its front face is substantially aligned with the rear, vertical, wall of the hopper 7 . The lower plunger will continue to retract further to a more retracted position. When its movement is reversed so that it begins its plunging action, the upper one will be drawn along therewith by friction. The amount of overhang provides the desired moving cavity . Such action may also be provided by two plungers of similar thickness. Another option includes the possibility of selectively locking the upper plunger in its retracted position.

Conclusion

Therefore it may be understood that the present invention overcomes deficiencies in the prior art by providing an improved method and apparatus which cuts certain wood pieces, known as mill ends , such that the chips can be used to make paper, cardboard, and other recyclable materials.

While this invention has been described in specific detail with reference, to the disclosed embodiments, it will be understood that many variations and modifications may be effected within the spirit and scope of the invention as described in the appended claims.