Patent Application
20220260199
This application claims priority from Canadian application no. 3109307, filed Feb. 18, 2021, which is incorporated herein by reference.
The present invention relates to a tacking laminated sawmill bed rail.
The sawmill rail also defines an inset rail guide to receive a track.
Portable sawmills provide the user with the flexibility to process logs into planks without having to rely on a large mill for processing. In addition, portable sawmills can be easily moved and set up, which allows users to process logs near where they are harvested, or on site where the resulting lumber is needed.
A number of portable sawmills have been described in the art, for example, U.S. Pat. Nos. 5,784,941, 4,275,632, 4,300,428, 4,235,140, 3,926,086, 4,245,535, and Canadian patent application 2,541,734 to the present applicant.
U.S. Pat. No. 5,243,892 discloses a portable sawmill with a frame base and an inverted U-shaped frame, supported by a carriage rolling along side tracks defined by the frame base. U.S. Pat. No. 4,640,170 discloses a portable saw mill with a frame that surrounds the log. U.S. Pat. No. 4,307,641 describes a portable sawmill comprising two skid rails, vertical support members, a pair of guide rails. U.S. Pat. No. 3,695,316 only uses one guide rail. Canadian Patent No. 1,200,180 describes a portable saw mill comprising a frame with a guide rail and a carriage moveable along the guide rail. U.S. Pat. No. 4,210,049 describes an “x” frame for holding a log, with a chain saw affixed to the frame in cantilever position for cutting logs crosswise. The log is held in the nook of the “x” frame.
To produce useful lumber, cuts must be straight and planar. This requires, at a minimum, a rigid, linear base to the sawmill, in the form of guide rails. The guide rails must resist/cope with many forces. During milling, complex forces, both rotary, vertical and horizontal can result in substantial and undesired force on the mill, potentially resulting in reduction in efficiency, reduction in accuracy and quality of the cut, and an increase in wear on the saw blade and sometimes its drive assembly and motor. In a portable sawmill, the mill base will be subjected to unwanted forces while being lifted, moved and placed. Between the weight of the sawmill carriage assembly and the large logs that are processed, components of the sawmill need to withstand a number of internal and external forces that are generated during milling.
This requires the components, and particularly those of the bed, sometimes referred to as a log deck, that act to stabilize the entire sawmill, to ideally have high compressive strength, tensile strength, torsional strength, and/or flexural strength. Portable sawmills are typically relatively large, complex and heavy structures constructed of heavy gauge steel utilizing multiple precision welds. The requirement for heavy gauge steel and precision welds adds costs, which is undesirable. There is a need in the industry to reduce cost and complexity of manufacture, while also increasing the strength of certain components of the portable sawmill.
According to an aspect of the invention, there is provided a laminated rail for a sawmill bed, the laminated rail comprising: an outer plate having a middle body portion, a top portion, and a bottom portion; an inner plate secured to the outer plate, the inner plate having a middle body portion, a top portion, and a bottom portion; wherein at least the middle body portion of each of the inner plate and the outer plate have a cross sectional configuration having multiple obtuse angles along a vertical axis to form a vertically upright rail and the inner plate is matingly received by the outer plate.
The cross-sectional configuration may be a zig-zag pattern. The outer plate and the inner plate may be secured together with fasteners. There may be multiple fasteners longitudinally along the length of the rail. The may be an upper lip extending outwardly from the top portion of the outer plate in a direction away from the inner plate.
There may be a lower flange extending from the bottom portion of the outer plate in a direction toward the inner plate. There may be an upper flange extending outwardly from the top portion of the inner plate in a direction away from the outer plate. There may be a lower flange extending from the bottom portion of the inner plate in a direction away from the outer plate.
In an embodiment, a channel is formed between the top portion of the inner plate and the top portion of the outer plate, the channel being shaped and dimensioned to receive and secure a track in a sandwich grip. There may be a track secured within the channel.
Also taught is a method of manufacturing a laminated rail for a sawmill bed, the method comprising: roll forming an outer plate having a middle body portion, a top portion, and a bottom portion with a cross sectional configuration with multiple obtuse angles along a vertical axis; roll forming an inner plate having a middle body portion, a top portion, and a bottom portion with a cross sectional configuration to allow the inner plate to be matingly received by the outer plate; and securing the outer plate to the inner plate to form the laminated rail.
Also taught is a laminated rail for a sawmill bed, the laminated rail comprising: an outer plate having a middle body portion, a top portion, and a bottom portion; an inner plate secured to the outer plate, the inner plate having a middle body portion, a top portion, and a bottom portion; wherein a channel is formed between the top portion of the inner plate and the top portion of the outer plate, the channel being shaped and dimensioned to receive and secure a track in a sandwich grip.
There may be a track secured within the channel. In an embodiment, at least the middle body portion of each of the inner plate and the outer plate has substantially the same cross sectional configuration to allow the inner plate to be matingly received by the outer plate.
In an embodiment, the cross-sectional configuration has multiple reflex angles and multiple obtuse angles along a vertical axis to form a substantially upright rail. The cross-sectional configuration may be a zig-zag pattern.
Also taught is a sawmill bed comprising at least one laminated rail as defined herein. Also taught is a a sawmill comprising the sawmill bed. The sawmill may have a wheel assembly comprising a main wheel and a control arm, the control arm extending downwards to a down portion, the down portion having a control wheel extending inwards, wherein the main wheel is configured to move along the track, and the control wheel is configured to engage with the upper flange.
Also taught is a method of manufacturing a laminated rail for a sawmill bed, the method comprising: roll forming an outer plate having a middle body portion, a top portion, and a bottom portion; roll forming an inner plate having a middle body portion, a top portion, and a bottom portion with a cross sectional configuration to allow the inner plate to be matingly received by the outer plate; forming a channel between the top portion of the inner plate and the top portion of the outer plate, the channel being shaped and dimensioned to receive and secure a track in a sandwich grip, and securing the outer plate to the inner plate with the track sandwiched in the channel to form the laminated rail.
Reference will now be made, by way of example, to the accompanying drawings which show example embodiments of the present application, and in which:
The following detailed description of the embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. While but a single embodiment of the present invention has been herein shown and described, it will be understood that various changes may be made without departing from the scope of the invention.
The present application is generally directed to a rail 18, such as the exemplary embodiment shown in
Referring to
The outer plate 24 has a middle body portion 27 flanked by a top portion 30 and a bottom portion 32. The outer plate 24 has an inner face 28 that communicates with the inner plate 26, and an outer face 29. In one embodiment, an upper lip 34 extends outwardly from the outer face 29 of the top portion 30 of the outer plate 24. Preferably the upper lip 34 extends substantially perpendicularly from the general plane of the body portion 27 can be seen in
The inner plate 26 has a middle body portion 38 flanked by a top portion 40 and a bottom portion 41. The inner plate 26 has an outer face 42 that ultimately communicates with the outer plate 24, and an inner face 43. In one embodiment, an upper flange 44 extends inwardly towards the center of the mill bed from inner face 43 of the top portion 40 of the inner plate 26. Optionally, in another embodiment, a lower flange 46 extends inwardly towards the center of the mill bed from inner face 43 of the bottom portion 41 of the inner plate 26, i.e. on the same side of the inner plate 26 as the upper flange 44. The flange 46 on the inner plate serves as an additional point of contact to secure the outer plate 24 to inner plate 26.
Flanges 44, 46 also act as stiffeners, which add rigidity to the bed 16. Therefore, the skilled worker will understand that they may manifest themselves in multiple shapes provided that they are able to perform this function.
For example, as can be seen in
The lower flange 46 preferably has a simpler structure, as at least a portion of the lower flange 46 is matingly received by the lower flange 36 from the outer plate 24. In the embodiment of the lower flange 46 shown in
In addition, flanges 44, 46 provide surfaces to connect the rail 18 to other parts of the mill. For example,
The cross sectional configuration of the body portion 27 of the outer plate 24 and the body portion 38 of the inner plate 26 are substantially the same to facilitate nesting of the inner plate 26 in the outer plate 24. In one embodiment, the cross sections of the body portions 27, 38 are substantially planar. However, according to an embodiment, the cross sections of body portions 27, 38 are substantially non-linear. For example, the cross sections of body portions 27, 38 may have e.g. a wave pattern or a zig-zag pattern. Alternatively, the embodiment shown in
In this context, a tacking pattern includes a pattern in which the metal of the plates 24, 26 is repeatedly angled in order for the body portion 27, 38 to progress from the bottom portion to the top portion. The multiple angles are not restricted to just right angles, but can include reflex angles and obtuse angles, or any combination thereof. The distance between angled portions in the tacking portion may also vary.
The term “tacking” as used herein is based on the use of the term in nautical applications. In the nautical usage, varying, sometimes unpredictable forces of wind and wave are confronted and controlled by use of varied angles of approach and resistance to those forces. In the present usage, varied, sometime unpredictable forces of downwards weight, lateral and horizontal movement of log and sawhead, blade rotation, and at times upwards lifting are confronted using the tacking configuration of varied angles of resistance to those forces. Thus, tacking, as used herein references multiple varying angles, including one or more of obtuse, reflex and right angles, each of which may travel in an inner or outer direction, to create in combination a substantially upright rail.
Preferably, the pattern configuration of the body portion 27, 38 results in the bottom portion and top portion of the plate 24, 26 being substantially planar, or in planes that are parallel to each other.
Including non-linear cross sectional configuration of body portions 27, 38 in the plates 24, 26 of the rail 18 imparts additional strength. The added strength provided by the tacking pattern enables the rail to better further resist forces on all axes, e.g. X, Y and Z. This allows rail 18 to better withstand torsion and/or compression forces, that arise during operation and transportation of the sawmill.
While the body portions 27, 38 of the inner and outer plates 24, 26 share substantially the same cross section to facilitate nesting of the inner plate 26 in the outer plate 24, in one embodiment, there is some deviation in the cross sections at the top portions 30, 40. As can be seen in
This arrangement, i.e. sandwiching track 58 between two plates 24, 26, is a fundamentally different arrangement over the prior art, which provides a stronger stable connection without requiring welding or bolting the track 58 or the like.
In
The type, structure and material of construction for the rail 18 is not particularly limiting. Preferably, the rail 18 is made of steel, such as stainless steel, carbon steel, or alloy steel. However, it is contemplated that with the increased strength created by the laminated rail, different materials could also be used such as aluminum.
The inner plate 26 and the outer plate 24 may be attached to each other by any suitable means known in the field. For example,
While the plates 24, 26 of the rail can be fabricated in a number of ways, such as bending the metal of the plates with a brake, or by extrusion of the plates, according to one embodiment, the plates 24, 26 are preferably made through roll forming. Roll forming is a type of rolling involving the continuous bending and often thinning of a long strip of sheet metal (typically coiled steel) into a desired cross-section. The strip passes through sets of rolls mounted on consecutive stands, each set performing only an incremental part of the bend, until the desired cross-section (profile) is obtained. Roll forming is ideal for producing constant-profile parts that had abnormal cross sections, such as the plates 24,26 of the rail 18 as defined herein.
Roll forming is, among the manufacturing processes, one of the simplest. It typically begins with a large coil of sheet metal, supported on an uncoiler. The strip is fed through an entry guide to properly align the material as it passes through the rolls of the mill, each set of rolls forming a bend until the material reaches its desired shape. Roll sets are typically mounted one over the other on a pair of horizontal parallel shafts supported by a stand(s). Side rolls and cluster rolls may also be used to provide greater precision and flexibility and to limit stresses on the material. The shaped strips can be cut to length ahead of a roll forming mill, between mills, or at the end of the roll forming line. Once the plates 24, 26 have been fabricated, they are connected together to form the laminate rail 18.
Unlike the prior art, the laminated structure of the rail 18 in conjunction with the non-linear nature of the cross section of the plates 24, 26 instills improved strength, rigidity, and stability. Furthermore, the design of the rail 18 can avoid the time and expense of welding, with the possibility of using lighter weight materials, as compared to carriage assemblies of the prior art. This reduces fabrication and shipping costs.
In addition, the centering of the track 58 is in the middle of the rail 18, rather than locating the track offset from the primary vertical plane of the rail 18, which results in the weight of carriage assembly 14 being placed substantially over the rail 18. Thus, less material is required to construct the sawmill 10, and the sawmill carriage assembly 14 will likely be better balanced and supported.
The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
| Number | Date | Country | Kind |
|---|---|---|---|
| 3109307 | Feb 2021 | CA | national |
