Patent Application
20050005574
The present invention relates to wood processing, and more particularly to cleaning contaminated lumber.
Lead-based paint is a known health hazard. Because older wood structures typically use lead-based paint, deconstruction and removal of these structures are hazardous activities. To avoid liability, a contractor must handle, contain, and dispose of the hazardous wood according to federal and state requirements.
Yet lead-painted structures often contain high quality lumber that, if salvaged, offers a beneficial resource from the hazardous waste of deconstruction. Wood recovery techniques have been developed to recycle the hazardous lumber into clean, sized stock and to safely contain the leaded waste for proper disposal. Moreover, recovery techniques have been developed that are portable to the site of deconstruction, which facilitates efficient processing and minimizes human contact with, and transportation of, the contaminated material.
U.S. Pat. No. 5,507,122 to Aulson discloses, for example, a de-leading unit having a mobile trailer and multiple woodworking devices therein, including a wood planer, chop saw, and table saw. The trailer has a receiving port to intake lead-painted wood and an exit port for feeding the de-leaded wood to workers outside the trailer.
While conventional systems such as the '122 patent can be effective, they have many shortcomings. For example, workers are often required within the trailer to manipulate lumber through various passes of separate woodworking devices, thereby exposing workers to airborne toxic debris concentrated within the trailer. Multiple woodworking devices and multi-pass processing also increase cost, potential for injury, and likelihood of error.
Moreover, current wood de-leaders generally lack a robust design necessary for efficient processing of deconstructed woods, which tend to have embedded metals and non-uniform slippery surfaces. One cause of inefficiency is the use of planers having round feed rollers with limited contact area and traction to drive wood. Accordingly, typical deleaders often allow deconstructed wood to slip during the drive operation, which requires manual attention and generates error in the finished woodpiece. Moreover, current de-leaders use standard cutting blades that exhibit premature wear when processing coated wood and damage when contacting embedded nails and metals. These blades cut whole pieces of waste that are cumbersome for safe handling, containment, and disposal.
Another drawback of current wood de-leaders is an inability to automatically process different, odd-shaped wood common to a deconstruction site. For example, deconstructed wood can range in size and shape with irregular contoured surfaces, such as in moldings and architectural woodwork. If at all capable, current de-leaders require continual adjustment and multiple passes to process the varying woodpieces, which slows processing, increases the volume of contaminated dust to control, and increases hazardous exposure to workers. Moreover, the drive mechanisms in de-leaders are typically, unstable when driving wood with irregular shape.
In addition, current de-leaders often cannot process wood beyond a threshold length. The de-leading unit of the '122 patent is so limited due to the trailer's internal dimensions and layout. Since longer wood has increasing recovery value, any limitation to wood length is counter productive to the recovery concept. Moreover, conventional de-leaders usually have excessive dimensions that hinder efficient portability to crowded urban work sites.
There is thus a need for an improved wood recovery and de-leading system having increased efficiency, robustness, versatility, compactness, cost effectiveness, and safety.
The present invention generally provides a wood de-leading device for de-leading a woodpiece. In one embodiment, the device includes a container having an inlet opening and an outlet opening. A plurality of rotatable wood removal cutters are located between the inlet and outlet openings, adapted to remove wood from different orientations of the woodpiece traveling in use along a feed path substantially aligned between the inlet and outlet openings. A drive mechanism is adapted to automatically drive the woodpiece along the feed path towards and beyond the cutters to the outlet opening in a single pass.
According to another embodiment, the wood de-leading device includes a mobile trailer having an inlet opening and an outlet opening. A plurality of rotatable wood removal cutters are located between the inlet and outlet openings, adapted to remove wood from different orientations of the woodpiece traveling in use along a feed path substantially aligned between the inlet and outlet openings. A drive mechanism adapted to automatically drive the woodpiece from the inlet opening along the feed path towards the plurality of rotatable wood removal cutters to the outlet opening in a single pass. A vacuum mechanism is included to maintain the trailer at a pressure lower than the ambient pressure (i.e., a negative air pressure with respect to the ambient pressure).
In another aspect of the invention, a method is provided for removing paint from a woodpiece. The method uses a container having an inlet opening and an outlet opening, with a wood de-leading device housed within the container. The method includes receiving the woodpiece through the inlet opening, driving the woodpiece from the inlet opening through the wood de-leading device, de-leading at least two surfaces of the woodpiece, and finally, outputting the woodpiece to the outlet opening. The driving, de-leading, and outputting are in a single automatic pass of the woodpiece along a feed path in substantial alignment with the inlet opening and outlet opening. Therefore the present invention provides the advantage that no workers are required within the trailer for system operability.
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
The present invention generally provides a wood recovery and de-leading system for de-leading deconstructed wood into clean, sized, and optionally profiled stock in a single pass, while containing the hazardous waste for safe and efficient processing and disposal. Although the system is described as operating on wood, a person having ordinary skill in the art will appreciate that the system can be used to clean and resize any number of materials regardless of coatings thereon.
The wood recovery and de-leading system includes a wood de-leading device 10, an example of which is shown in perspective view by
Referring to
In a preferred embodiment, any wood removal cutter 12-15 can be adjustable to remove a desired amount of wood from the respective orientation of the woodpiece. For example, the cutters can be adjusted to resize (and de-lead) the woodpiece into lumber having any dimension, such as ⅝ inch by 3¾ inch stock. Those having ordinary skill in the art will appreciate various means for providing such adjustability to a cutter, for example, via a hand crank 24 as shown. Although the wood removal cutters are described as being configured to provide a finished woodpiece 20b having a rectangular or square cross-section, the cutters can be otherwise configured to provide a finished woodpiece having any cross section. Moreover, those having ordinary skill in the art will understand that the wood removal cutters are preferably adapted to impress any desired profile (e.g., contour) to the finished woodpiece 20b.
The wood de-leading device 10 has a robust design particularly effective to withstand the heightened demands called upon by the unique attributes of deconstructed wood, such as embedded metals, slippery surfaces, irregular shapes, and heavy stock removal. For example, in the preferred embodiment, the wood removal cutters 12-15 are composed of a material rigid enough to remove wood but pliable enough to avoid premature wear (e.g., chipping) when processing embedded metals and rough coatings common to deconstructed wood. In a particularly effective embodiment, the wood removal cutters are constructed of a soft carbide material. Those having ordinary skill in the art will appreciate other cutter materials having similar ability to avoid premature wear when processing deconstructed wood.
The wood removal cutters can include standard saw blades having a typical shape. However, such blades remove whole portions of wood, which complicates waste containment and safety. To overcome this difficulty, in the preferred embodiment, the wood removal cutters can include so-called hogging cutters, which are thicker than standard saw blades. A hogging cutter operates not by sawing off a whole portion of the woodpiece, but rather, by pulverizing the removed wood into dust, chips, and shavings more easily contained for efficient disposal. If used, a hogging cutter can be configured to any thickness for a desired amount of wood removal.
Due to course coatings, embedded metals, slippery surfaces, and heavy stock removal, deconstructed wood tends to resist feeding through the wood removal cutters 12-15 and to resist traction with the drive mechanism 18 of the wood de-leading device 10. These complications are aggravated by the inefficient design of conventional drive mechanisms, which use feed rollers having minimal tangential drive contact with the woodpiece. As a result, conventional drive mechanisms often slip during the feed operation. To overcome this problem, the present invention provides a wood de-leading device 10 having a drive mechanism 18 configured to feed deconstructed wood through the cutters 12-15 with improved traction and stability.
In the preferred embodiment, the drive mechanism 18 is adapted for distributed driving contact along a first surface of the woodpiece. As shown in
In the preferred embodiment, the traction surface 32 of the drive mechanism 18 ranges along the feed path of the wood de-leading device, adjacent to at least the top and side wood removal cutters. Of course, the position of the traction surface can be anywhere before, during, and/or after any of the cutters sufficient to drive the woodpiece 20 beyond all of the cutters during operation. Extending the traction surface beyond the cutters facilitates feeding the finished woodpiece 20b through to the outlet. Without so extending the traction surface, such feed-through of the woodpiece is aided by abutting successive woodpieces in a continuous manner, such that each incoming woodpiece pushes the finished woodpiece 20b beyond the traction surface 32 to the outlet.
To further facilitate positive feeding of the woodpiece, the wood de-leading device 10 can include an urging device 38 adapted to increase frictional forces between the woodpiece 20 and the traction surface 32 of the drive mechanism 18. In the preferred embodiment, the urging device 38 is a set of rollers adapted to urge the woodpiece against the traction surface 32 of the feeding conveyor 30 during use. The rollers can be configured to urge the woodpiece in any direction that increases feed traction. Preferably, the rollers urge the woodpiece in a direction substantially orthogonal to the traction surface 32 of the feeding conveyor 30. Note that the urging device 38 is not limited to rollers. Those having ordinary skill in the art will appreciate objects shaped other than rollers to likewise provide the urging force while not resisting feed-through of the woodpiece 20.
To allow for irregular topologies of a woodpiece, the urging device 38 can be configured with automatic conforming adjustment. In the preferred embodiment, coupled to each urging roller 38 is a bias mechanism 40 adapted to bias the roller against the woodpiece, with a range of travel having a component in the urging direction. So configured, the roller 38 provides the urging force while automatically adjusting its position to accommodate any irregularity in the topology of the incoming woodpiece 20a. The urging device can have a range of travel in the urging direction from about a quarter inch to about several inches, and more preferably, about 2 inches. Though in
To prevent unwanted kickbacks of a woodpiece passing through the cutters, the wood de-leading device can include an anti-kickback mechanism 42. The anti-kickback mechanism is configured to allow free passage of the woodpiece 20 in the feed direction while preventing movement of the woodpiece in the opposite direction. In the preferred embodiments of
To prevent dangerous projectiles of debris during processing, the wood de-leading device 10 can include a self forming anti-projectile mechanism. In a preferred embodiments of
The wood de-leading device is housed in a container to facilitate portability and hazardous waste management.
Referring to
In the preferred embodiment, the trailer is configured to provide the wood recovery and de-leading system as a consolidated unit for efficient safety and operation.
In the preferred embodiment, the trailer is configured with other optional features and systems that facilitate waste confinement and safety. For example, the inlet and outlet openings of the trailer preferably include access curtains and hatches: access curtains to limit waste from exiting the openings during use and access hatches to optionally seal the openings during periods of non-use. In the preferred embodiment of
In the preferred embodiment, auxiliary systems like an electrical generator, fire suppression system, vacuum system, air compressor, and the like, are housed within the trailer to provide a self contained de-leading unit. However, any or all auxiliary systems may be located outside the trailer, for example, in a separate container or trailer.
Referring to
One of ordinary skill in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described. Rather, the invention covers all such changes and modifications as fall within the true spirit and scope of the invention, for which letters patent is applied. All publications and references cited herein are expressly incorporated herein by reference in their entirety.
