Portable Sawmill With Folding Bed

A sawmill assembly includes a bed and a carriage. The bed has a pair of substantially parallel rails, and the carriage is movably supported along the rails. The bed includes an extension bed member pivotably attached to a main bed member with a combination bunk/hinge to allow an operator to fold the bed between an extended in use position and a stowed position for transporting the sawmill assembly to or from a work site with a tow vehicle.

FIELD OF THE INVENTION

The present invention relates generally to the field of sawmills. More particularly, the present invention relates to portable sawmills having a cutting head mounted to a carriage movable along rails supported on a bed, wherein the saw head comprises a band saw cutting blade.

BACKGROUND

A sawmill typically includes three main components, namely, a bed, a carriage, and a saw head. The bed is adapted to support a log extending horizontally along the bed. The carriage is mounted to the bed for horizontal movement along the length of the log, and the saw head is mounted to vertical posts on the carriage. The vertical posts of the carriage permit vertical movement of the saw head relative to the carriage, and the carriage is adapted for horizontal movement along the bed. Typically, the carriage rides on a section of track including a pair of parallel rails. The saw head typically includes a band saw blade to cut the log as the carriage is moved horizontally along the bed. U.S. Pat. No. 4,275,632 to Ross, and U.S. Pat. No. 7,784,387 to Dale disclose examples of such a sawmill.

A problem with the sawmills disclosed in the U.S. '632, and '387 patents, and others like them, is that in order to be transportable, conventional sawmills are provided with a track that is limited in length. In particular, trailerable sawmills have tracks limited to lengths that can be fit on trailers that have overall lengths of at most 16 to 20 feet, since longer trailers become difficult to maneuver, or may not comply with local laws. Accordingly, it is common for such trailerable sawmills to have a bed and track that is no longer than about 10 feet, which limits the length of logs it can be used with to about 10 feet 4 inches.

U.S. Pat. No. 719,585 to Hanssler disclosed one attempt for extending a track in a portable sawmill using hinges to hingedly attach track-sections to both ends of a track. The folding track-sections are capable of swinging upwardly to rest on top of the machine when not in use. Hanssler noted that in this way a track is formed which when in its folded position will be of substantially the same length as the machine-frame and when in its position for use will be long enough for all of the ordinary purposes for which the portable sawmill is designed. However, a problem with the Hanssler sawmill is that it is designed with a circular saw fixedly mounted on the side of the portable sawmill, wherein a separate carriage riding on the track is required to move workpiece material, such as a log, to and through the circular saw for cutting. Additional problems associated with the Hanssler sawmill relate to the simple hinged attachment of the track-sections to the track which cause issues for levelling and aligning of the rails. Such unlevelled and/or misalignment rails would make it difficult if not impossible to maintain a precise cut through the workpiece material, along the length of the workpiece material, with the horizontal band saw sawmills of the type described above, namely those having a horizontal cutting head mounted to a carriage adapted to ride on rails. This is not a problem Hanssler needed to contend with because Hanssler's sawmill employed a vertically oriented circular saw, meaning that bumps, or other changes in elevation in the track would not translate into changes in the cut being made to the workpiece material. However, it will be appreciated that in the case of horizontal band saw sawmills, such defects in the rails will translate to the cuts in the workpiece material by the band saw blade.

SUMMARY OF THE INVENTION

A sawmill assembly includes a bed and a carriage. The bed has a pair of substantially parallel rails, and the carriage is movably supported along the rails. The bed includes an extension bed member pivotably attached to a main bed member with a combination bunk/hinge to allow an operator to fold the bed between an extended in use position and a stowed position for transporting the sawmill assembly to or from a work site with a tow vehicle.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is described in more detail with reference to exemplary embodiments thereof as shown in the appended drawings. While the present invention is described below with reference to the embodiments, it should be understood that the present invention is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and embodiments which are within the scope of the present invention as disclosed and claimed herein.

A sawmill apparatus10according to an embodiment of the present invention is shown inFIGS.1to3, in an in-use configuration. The sawmill apparatus10includes a bed12and a carriage14. In an embodiment, the bed12may be in the form of a trailer with one or more pairs of road, or off-road wheels16, a tongue18, a hitch20, and a trailer jack22, as well as any other elements necessary or desirable to allow the sawmill apparatus10to be towed by a tow vehicle, in a conventional manner. The bed12has a pair of substantially parallel rails24, and the carriage14is movably supported along the rails24, on carriage wheels26as shown. In an embodiment, the rails24may be L-shaped in cross-section, defining vertical portions comprising wheel contacting support surfaces for the carriage wheels26, and horizontal portions for attachment to the bed12. Furthermore, the rails24may be formed from a plurality of rail sections (not shown).

Several log bunks28are positioned between the rails24and arranged in the bed12to support a workpiece material (not shown) thereon. By way of example, the workpiece material may be made from wood, such as a log. Log bunks28are, in an embodiment, structural components of the bed12that support the workpiece material during the milling/sawing operation. The workpiece material rests on the log bunks28and in turn they carry the entire weight of the workpiece material. In an embodiment, the log bunks28may also add to the overall structural strength of the bed12as they tie into the rails24to help keep them true and square. It has been found that providing a level square bed12is desirable for achieving wood boards of consistent thickness since the carriage14follows along the rails24.

In an embodiment, one or more log supports30and clamps32are also provided on the bed12and configured to secure the workpiece material to the bed12between the rails24. As will be appreciated, the log supports30and clamps32may be used to help prevent movement of the workpiece material during operation of the sawmill apparatus10. Additionally, a plurality of adjustable feet34may be provided under the bed12and configured to permit a sawmill operator to level the bed12during installation and setup and provide uniform support for the rails24when the bed12is installed on uneven ground. In an embodiment, the bed12will also be provided with carriage stops36at both ends of the rails24to ensure that the carriage14does not inadvertently roll off of the rails24at one end38or the other40. In an embodiment also, the log supports30and clamps32may be removably, and slidably retained in holders42, to allow their heights above the rails24to be adjusted. In this way, the heights of the log supports30and clamps32may be individually adjusted by the operator, or they may be individually removed from the bed12, as needed so as not to interfere with the movement of the carriage14along the rails24between the one end38of the bed12and the other end40of the bed12. Similarly, the adjustable feet34may be removably and slidably retained in holders42, to allow their lengths below the rails24to be adjusted.

In an embodiment, the bed12may be configured as a kit of parts, to be assembled by the operator without the need for specialized tools.

With continued reference toFIGS.1to3, the carriage14has a frame44with two sides46,48that straddle the bed12, and is moveably supported along the rails24on the carriage wheels26, between the one end38and the other end40. The carriage wheels26may include annular grooves to limit lateral movement on the rails24. In an embodiment, the frame44is configured to carry a saw head50attached or mounted thereto. In an embodiment, the saw head50includes a band saw, having a blade52adapted to cut the workpiece material, a motor54(i.e. electric or internal combustion motor) to drive the band saw, and other components that may be necessary or desirable to operate and control the band saw, such as, for example, a fuel tank56, and a throttle58.

The saw head50is configured to cut the workpiece material supported on the bed12, as the carriage14is moved along the rails24in at least one direction60, for example, from the one end38of the bed12to the other end40of the bed12. Of course, it will be appreciated that the saw head50may also be configured to cut the workpiece material in a direction opposite to the at least one direction60. In an embodiment, the saw head50may be configured to cut the workpiece material in both directions, for example, by providing the blade52with cutting surfaces facing both the one end38and the other end40. All such embodiments are comprehended by the present invention.

In an embodiment, the carriage14may be configured to be moved along the rails24by the operator between the one end38and the other end40, while the band saw is on and driving the blade52. For example, the operator may apply force to the carriage14to cause it to move in the one direction60or the opposite direction. A handle62may be provided on the frame44to facilitate the pushing or pulling the carriage14by the operator.

In an embodiment, the bed12includes an extension bed member64which is pivotably attached to a main bed member66with a combination bunk/hinge assembly68. As shown, the main bed member66may include the road or off-road wheels16, tongue18, hitch20, trailer jack22, as well as any other elements necessary or desirable to allow the sawmill apparatus10to be towed by a tow vehicle, in a conventional manner.

According to an embodiment of the present invention, the saw head50is attached to the frame44together with an element to raise or lower the saw head50in the carriage14along a vertical axis of the carriage14, with the blade52remaining substantially perpendicular to the vertical axis of the carriage14. In an embodiment, the raising and lowering of the saw head50may be achieved by slidably mounting the saw head50to a pair of vertically oriented posts70at the sides46,48of the frame44, and operatively connecting the sliding saw head50to a winch and pulley assembly. By way of example, as best seen inFIG.3, an element to raise or lower the saw head50may include at least one guide sleeve72adapted to slidingly accommodate a vertically oriented post70on one side46of the frame44. In an embodiment, the saw head50includes two guide sleeves72adapted to slidingly accommodate vertically oriented posts70on both sides46and48of the frame44. A cable74connects a winch76and pulleys78mounted to the frame44, to the sliding saw head50to allow the operator to raise and lower the saw head50by manipulating the winch76. It will be appreciated that raising or lowering the saw head50translates into raising or lowering of the blade52of the saw head50above the bed12, enabling the operator to adjust the height of the blade52above the bed12.

Accordingly, the operator may manipulate the element to raise or lower the saw head50to cut the workpiece material supported on the bed12at a desired height relative to the bed12. In this way, the operator may cut a piece from the workpiece material, such as for example, a flat board, having a desired thickness. However, the person skilled in the art will recognize other known ways of raising and lowering the saw head50. All such other known ways of raising or lowering the saw head50are comprehended by the present invention.

In an embodiment, the carriage14may also be configured as a kit of parts, to be assembled by the operator without the need for specialized tools.

In an embodiment, the bed12and the carriage14may be configured as a kit of parts, to be assembled by the operator into a sawmill assembly, configured to mount the saw head50. It is contemplated that the combination bunk/hinge assembly68and the sawmill assembly may be provided as standalone items, to enable operators to build, retrofit, or modify sawmills in accordance with the present invention. In an embodiment, however, the kit of parts may also include the saw head50, to permit the operator to assemble a complete sawmill assembly10. All such embodiments are comprehended by the present invention.

Accordingly, it will be appreciated that operation of the sawmill apparatus10in the configuration shown inFIGS.1to3permits the operator to make substantially horizontal cuts through the workpiece material by pushing or pulling the carriage14from the one end38to the other end40of the bed12. Furthermore, it will be appreciated that by using the sawmill apparatus10in the configuration shown inFIGS.1to3to make a pair of sequential, horizontal cuts in the workpiece material, and manipulating the winch76to lower the saw head50between the pair of cuts, the operator may cut a piece from the workpiece material, such as for example, a flat board, having a desired thickness.

Although, the saw head50according to an embodiment of the present invention includes a band saw having a blade52oriented substantially perpendicular to a vertical axis of the carriage14, it is contemplated that the band saw may be replaced with another known type of saw such that the blade52is held in the carriage14substantially perpendicular to a vertical axis of the carriage14. By way of example only, such other known types of saw may include a chain saw, a reciprocating saw, or a circular saw. All such embodiments are comprehended by the present invention.

With reference now toFIGS.4to9the sawmill apparatus10is shown in a stowed, transportable configuration, which is ready to be hooked up to a hitch ball, for example, on a tow vehicle, such as a pickup truck (not shown), in a conventional manner, and towed to or from a work site. In the example shown in the figures, the longitudinal axis of the extension bed member64is at an angle 27° relative to the longitudinal axis of the main bed member66, when the extension bed member64is in the stowed position. In an embodiment, the angle between the longitudinal axis of the extension bed member64and the longitudinal axis of the main bed member66may be in a range of 26° to 28°, when the extension bed member64is in the stowed position. However, one of the reasons for providing an extension bed member64that can be folded to the stowed position is to increase the maneuverability of the sawmill apparatus10when being transported. It has been found that depending on the design of the sawmill apparatus10, the benefit of increased maneuverability may be accomplished by providing the angle between the longitudinal axis of the extension bed member64and the longitudinal axis of the main bed member66in a range of 90° to 0°, wherein an angle of 180° has the extension bed member64fully extended to the in use position, 90° has the extension bed member64standing upright, and 0° has the extension bed member64folded back fully on the main bed member66. All such embodiments are comprehended by the present invention.

In an embodiment, when the extension bed member64is in the in use position, the longitudinal axis of the extension bed member64extends substantially parallel to the longitudinal axis of the main bed member66, and the wheel contacting support surfaces of the rails24of the extension bed member64are aligned with the wheel contacting surfaces of the rails24of the main bed member66.

As best seen inFIG.4, when the sawmill apparatus10is to be transported to or from a work site by being towed behind a tow vehicle, the extension bed member64is pivoted up and back towards the carriage assembly14such that the one end38engages the carriage assembly14.

In an embodiment, the one end38may include an element to releasably secure the one end38to the carriage assembly14, when the extension bed member64is in the stowed position, as best seen inFIG.6. By way of example, the element may include a latch having a catch member80on the carriage assembly14, and a striker peg82on the one end38. In an embodiment, two such latch members may be provided, one on each side of the sawmill apparatus10. In an embodiment, the striker peg82may have a cylindrical shape sized to engage a tapered slot84in the catch member80. As will be appreciated the tapered slot84can help guide the striker peg82to its resting position within the pit of the tapered slot84. Although the example shown shows the striker peg82attached to the extension bed member64and the catch member80attached to the carriage assembly14, it is contemplated that the striker peg82may be attached to the carriage assembly14, with the catch member80attached to the extension bed member64. Additionally, the catch member80may be provided with an element (not shown) for releasably retaining the striker peg82within the tapered slot84, wherein the element allows the striker peg82to enter the tapered slot84but requires an action by the operator to allow the striker peg82to exit the tapered slot84. All such embodiments are comprehended by the present invention. What is important is that the one or more latches may be used to releasably secure the one end38of the carriage assembly14when the extension bed member64is in the stowed position.

In an embodiment, as best seen inFIG.7, the sawmill apparatus10may include an element to releasably lock the carriage assembly14in position relative to the main bed member66when the extension bed member64is in the stowed position. By way of example, the locking means may include a lock pin86, and matching apertures88in the frame44at the carriage wheels26, and in a rail24. In this way the operator may pass the lock pin86through apertures in the frame and the rail24, essentially fastening the carriage assembly14to the main bed member66, thereby preventing horizontal movement of the carriage assembly14along the rails24of the main bed member66. The lock pin86will also help prevent the carriage assembly14from lifting up from the rails24, for example while the sawmill apparatus10is being transported over a rough or bumpy road.

Advantageously, securing the extension bed member64to the carriage assembly14in this manner allows the extension bed member64to be used as a brace or truss, which helps prevent the carriage assembly14from tipping over during transport. As will be appreciated, frame44of the carriage assembly14, the portion of the main bed member66extending between the carriage assembly14and the combination bunk/hinge assembly68, and the extension bed member together form a triangle, which is structurally robust.

As seen inFIG.5, the combination bunk/hinge assembly68includes a special shaped hinge slot90allowing the user to pull the extension bed member64away from the main bed member66into a pivot position which facilitates folding of the extension bed member64into the stowed position. The hinge slot90includes a detent92at one end that catches a hinge pin94when the operator pulls the extension bed member64away from the main bed member66. The detent92provides a shoulder for the hinge pin94to bear against as the operator folds the extension bed member64back onto the carriage assembly14to prevent the hinge pin94from sliding in the hinge slot90during the folding step. As will be appreciated, this makes it easier for the operator to fold the extension bed member64back on to the carriage assembly14and engage the catch member80with the striker peg82. In an embodiment, the hinge slot90has a slide portion91, adapted to allow the hinge pin94to slide there along, so that the extension bed member64may be pulled away from the main bed member66by a predetermined distance before the hinge pins94drop into the respective detents92. In an embodiment, each detent92is a curved portion at the end of the slide portion91of the hinge slot90, which is oriented to allow the hinge pin94to drop into it, when the extension bed member64is pulled away from the main bed member66during folding of the extension bed member64from the in use position to the stowed position. Each detent92is further configured to allow the hinge pin94to pop out of it and slide along the slide portion91of the hinge slot90, when the extension bed member64is pushed toward the main bed member66during unfolding of the extension bed member64from the stowed position to the in use position and securement to the main bed member66.

With reference now toFIGS.8and9, the extension bed member64may be secured in the stowed position with one or more striker pegs82engaged by one or more relatively positioned catch members80, using a ratchet strap96, or the like. However, other elements for securing the extension bed member64in the stowed position that will be available to persons skilled in the art are comprehended by the present invention, including ropes, belts, bungee cords, and the like.

With reference now toFIGS.10to12, an embodiment of the combination bunk/hinge assembly68is shown apart from the bed12. Advantageously, the combination bunk/hinge assembly68includes a bunk surface98for supporting a workpiece material, such as a log, rested on top of it. In an embodiment, the bunk surface98is substantially level with support surfaces on the log bunks28, when the extension bed member is in the in-use position. In this way, the combination bunk/hinge assembly68functions as another log bunk28, and together with the other log bunks28in the bed12they can carry the entire weight of the workpiece material. Like the log bunks28, the combination bunk/hinge assembly68may also add to the overall structural strength of the bed12as it ties into the rails24. Accordingly, the combined bunk/hinge assembly68combines the features of a hinge with a log bunk, among other features.

As can be seen inFIG.10, the combination bunk/hinge assembly68has two halves that are pivotably attached together. The two halves are more clearly seen in the disassembled view shown inFIG.11. A first hinge half100is configured for attachment to the main bed member66, and a second hinge half102is configured for attachment to the extension bed member64. In this example, the first hinge half100has a bunk surface98on its top for supporting a workpiece material, such as a log, four first hinge members104, each having a hinge slot90, a pair of draw latches106, and a pair of attachment flanges108for attaching the combination bunk/hinge assembly68to the main bed member66. In an embodiment, the first hinge half100may also include a pair of holders42for slidably retaining adjustable feet34.

In the embodiment of the invention shown in the figures, the rails24of the extension bed member64are spaced apart by the same distance as the rails24of the main bed member66. However, this is not essential, as the rails of the extension bed member64may be spaced apart by a different distance than the rails of the main bed member66, whether greater or lesser, in other embodiments.

The embodiment of the invention shown in the figures also shows the bunk surface98of the combination bunk/hinge assembly68spanning a major portion of the distance between the rails24. In an embodiment, the bunk surface98of the combination bunk/hinge assembly68spans at least 50% of the distance between the rails24of the main bed member66or the extension bed member64. In an embodiment, the bunk surface98of the combination bunk/hinge assembly68spans at least 90% of the distance between the rails24of the main bed member66or the extension bed member64. Furthermore, it is contemplated that the bunk surface98may be configured to be greater than the distance between the rails24of the main bed member66or the extension bed member64.

The draw latches106may be configured to secure the second hinge half102to the first hinge half100when the extension bed member64is pivoted out into the extended, horizontal, in use position, as will be described in more detail below.

In this example, the second hinge half102has four second hinge members110, each carrying a hinge pin94. Additionally, the two center-most second hinge members110also define draw latch saddles112. In an embodiment, the hinge pins94may be threaded bolts secured through hinge slots90with nuts114. In an embodiment, the second hinge half102may also include a pair of draw latch slots116to allow hook ends118of the pair of draw latches106to pass therethrough from the first hinge half100to the second hinge half102to engage the respective draw latch saddles112when the combination bunk/hinge assembly68is secured in the in use position, with the extension bed member64extended. In an embodiment, the length of the hook ends118in the draw latches106may be adjustable. The second hinge half102may also include attachment flanges120configured to attach the combination bunk/hinge assembly68to the extension bed member64.

As best seen inFIGS.13and14, the first hinge half100may be attached to the main bed member66, and the second hinge half102may be attached to the extension bed member64, and the first and second hinge halves100,102may be attached together by threading nuts114on to threaded hinge pins94.

Embodiments of the present invention utilize fasteners, such as threaded bolts and nuts, which may be provided as a kit for the operator to assemble with simple tools. However, it will be appreciated that other manners of attaching components together will be known to persons skilled in the art, including welding, and riveting, for example. All such embodiments are comprehended by the present invention.

Additionally, the combination bunk/hinge assembly68may include projections, such as a tapered end set screws122, on the second hinge half102for engaging mating cavities or openings124in the first hinge half100, when the combination bunk/hinge assembly68is in the in use position. The tapered end set screws122and mating openings124may be sized, shaped and positioned to guide into and lock the relative vertical and/or lateral positions of the first and second hinge halves100,102, when the combination bunk/hinge assembly68is unfolded and secured into the in use position. In this way, the tapered end set screws122and openings124may be used to ensure that the extension bed member64and its rails24are aligned with the main bed member66and its rails24when the extension bed member64is unfolded and secured into the in use position with the draw latches106. It is contemplated that the positions of the tapered end set screws122and openings124may be reversed, such that all of the tapered end set screws122are on the second hinge half102, and all of the openings124are on the first hinge half100. It is also contemplated that tapered end set screws122may be positioned in both the first and the second hinge halves100,102, with the openings124positioned in matching relation in both the first and second hinge halves100,102.

In an embodiment, the length that the tapered end set screws122project outwardly from the first hinge half100is adjustable. By way of example, the tapered end set screws122may be threaded and carried in a threaded bore on the first hinge half100whereby tightening or loosening the tapered end set screws122causes them to extend or retract relative to the respective opening124on the second hinge half102. In an embodiment, the adjustment of each tapered end set screw122may be secured with a pair of jam nuts126.

It is contemplated that projections and cavities or openings124may be omitted according to other embodiments of the present invention. Furthermore, other forms of projections than the tapered ended set screws122disclosed herein may be used as will now be appreciated by persons skilled in the art. All such embodiments are comprehended by the present invention.

With reference now toFIGS.15and16, the draw latches106of an embodiment are arranged and configured so that their hook ends118engage the respective draw latch saddles112on the second hinge members110, to draw the second hinge half102towards the first hinge half100, to seat the tapered end set screws122in the respective openings124, and also to draw at least one of the second hinge members110towards the adjacent first hinge member104. In this way, the draw latches106, in combination with the draw latch saddles112, the tapered end set screws122, and the openings124help to secure the first and second hinge halves100,102together, when the combination bunk/hinge assembly68is in the in use position. This helps ensure that the extension bed member64and its rails24are aligned with the main bed member66and its rails24when the extension bed member64is folded out and secured in the in-use position.

With reference now toFIG.17, it can be seen that the engagement of the hinge slots90by the hinge pins94on the one hand, and the engagement of the openings124by the tapered end set screws122on the other hand, regulate the space128between the first and second halves100,102of the combination bunk/hinge assembly68, according to an embodiment of the present invention. As will be appreciated, increasing or decreasing the space128will cause a corresponding increase or decrease to the angle of the extension bed member64relative to the main bed member66, when the combination bunk/hinge assembly68is secured in the in use configuration.

InFIG.18, for example, the combination bunk/hinge assembly68is shown secured in the in use configuration after being adjusted so that the extension bed member64and the main bed member66are aligned, and the tops130of the rails24of the extension bed member64are level with, and at the same height, as the tops130of the rails24of the main bed member66. Furthermore, the rails24of the extension bed member64and the rails24of the main bed member66are also laterally aligned, as best seen inFIG.2, for example.

With continued reference toFIG.18, rail support members132may be attached to the main bed member66underneath the rails24to extend out from the main bed member66, as shown. The rail support members132, which may be provided as rigid plates, help align the rails24of the extension bed member64and the rails24of the main bed member66, and guide the extension bed member64into position against the main bed member66, when the operator is unfolding and securing the combination bunk/hinge assembly68with the extension bed member64in the in use position. When the rail support members132are present, the slide portions91of the hinge slots90will each have a length that is at least the length by which the rail support members132extend out from the main bed member66. This allows the rails24of the extension bed member64to be pulled clear of the rail support members132by the operator, before the hinge pins94drop into the respective detents92.

Additionally, notches134may be provided in the ends136of the rails24of the extension bed member64abutting the ends138of the rails24of the main bed member66. The notches134are sized and shaped to help ensure that the ends136and138abut squarely with one another. In other words, the notches134extend across the entire length of the horizontal portion of the “L” beam forming each rail24of the extension bed member64, ensuring that the vertical portion of the “L” beam forming each rail24of the extension bed member64contacts the respective vertical portion of the “L” beam forming each rail24of the main bed member66. The horizontal portions of the “L” beams are set back from the respective vertical portions, thereby avoiding contact between the horizontal portions of the ends136and138.

With reference toFIG.19, the extension bed member64may be configured as a kit of parts, to be assembled by the operator without the need for specialized tools.

In an embodiment, the hinge slots90have a slide portion91, adapted to allow the hinge pin94to slide there along, so that the second part of the hinge assembly may be pulled away from the first part by a predetermined distance. In an embodiment, the hinge slots90may also have a pivot portion extending from the slide portion91, sized and shaped to hold the hinge pin94from sliding while the extension bed member64is being unfolded from the stowed position into the in use position, and vice versa. In an embodiment, the pivot portion is a curved section oriented to allow the hinge pin94to drop into it, when the second hinge half102of the hinge assembly is pulled away from the first hinge half100during unfolding of the track extension from the stowed position to the in use position. In this regard, the hinge slot90may be generally L-shaped.

Good results have been obtained by providing the curved portions of the detents92with curvatures that are greater than the curvatures of the curved portions of the hinge pins94, and providing each slide portion91with a length of at least half a diameter of the respective hinge pin94. By way of example, with a hinge pin94having a diameter of 11 mm, the length of the slide portion91of the respective hinge slot90may be at least 5.5 mm, and good results have been obtained with a length of 2.3 cm. Accordingly, 2 cm to 10 cm is generally a good range for the lengths of the slide portions91.

Having described embodiments of the sawmill apparatus10, including a combination bunk/hinge assembly68, it can now be understood how the sawmill apparatus10shown inFIGS.1and2may be prepared for transport to or from a work site, as shown inFIG.4. For example, the operator may start by unlatching the draw latches106. Next, the operator may lower the saw head50to a bottom position and move the carriage assembly14along the bed12to the travel position, shown inFIGS.1and2. Once in the carriage assembly14is in the travel position, the operator may insert the locking pins86through the apertures88to lock the carriage assembly14in place on the rails24. Next, the operator may pull the extension bed member64away from the main bed member66to slide the hinge pins94along the slide portion91of the hinge slot90until they drop into the detents92. The operator may then fold the extension bed member64back towards the carriage assembly14by pivoting the extension bed member64until its striker pegs82engage the catch members80and are guided into their resting positions by the tapered slots84. Next, the operator may proceed to wrap the ratchet strap96around the one end38of the extension bed member64and a log bunk28located below, to secure the one end38to the carriage assembly14. Finally, the operator may connect the hitch20to a hitch coupler on a tow vehicle, and raise up all adjustable feet34, and lift and rotate the trailer jack22off the ground.

Similarly, to prepare the sawmill shown inFIG.4for use, as shown inFIGS.1and2, the operator may take the following steps. For example, the operator may start by rotating and lowering the trailer jack22to contact the ground and unhitch the hitch20from the hitch coupler on the tow vehicle. Next, the operator may continue to crank the trailer jack22to lift the tongue18so that the adjustable feet34in the main bed member66can be lowered. Next, the operator may place a level across the rails24at the other end40and maneuver the sawmill apparatus10until the main bed member66is laterally level. Once the main bed member66is laterally level, the operator may secure the adjustable feet34in position. Next, the operator may detach the trailer jack22from the tongue18and attach it to the rear end of the main bed member66. After placing a level across the log bunks28at the rear end of the main bed member66, parallel to the rails24, the operator may crank the trailer jack22to lift the rear end of the main bed member66until the main bed member66is longitudinally level. Next, the operator may lower the adjustable feet34at the rear end of the main bed member66and secure them in position, using the T-handles provided at holders42. Having set up the adjustable feet34in the main bed member66, the operator may remove the ratchet strap96, and unfold the extension bed member64by pivoting the extension bed member64away from the carriage assembly14, with the hinge pins94being held in the detents92of the hinge slots90, until the extension bed member64is in an extended, substantially horizontal position. At this point, the operator may push the extension bed member64towards the main bed member66to pop the hinge pins94out of the detents92to slide along the slide portions91of the hinge slots90until the second hinge half102presses against the first hinge half100. The operator may then secure the combination bunk/hinge assembly68with the draw latches106. Next, the operator may place a level longitudinally across the bunk surface98of the combination bunk/hinge assembly68bunk, and the rear most log bunk28on the main bed member66, and adjust the adjustable feet34until the extension bed member64is level with the main bed member66. Finally, the operator may reattach the trailer jack22back on the tongue18.

While reference has been made to various embodiments of the invention, other variations, implementations, modifications, alterations, and embodiments are comprehended by the broad scope of the appended claims. Some of these have been discussed in detail in this specification and others will be apparent to those skilled in the art. Those of ordinary skill in the art having access to the teachings herein will recognize these additional variations, implementations, modifications, alterations and embodiments, all of which are within the scope of the present invention, which invention is limited only by the appended claims.