Truss fabrication apparatus

A truss assembly apparatus and a method for assembling a truss utilizing the apparatus, the apparatus comprising a truss table having a work surface divided into a first and second assembly zone. The apparatus further includes first and second clamping assemblies for clamping the truss in the first and second assembly zones. The apparatus includes a flip-over assembly having a flip-over arm movable relative to the truss table for moving the truss from a first truss position in the first assembly zone, wherein a first truss face contacts the work surface, to a second truss position in the second assembly zone, wherein a second truss face contacts the work surface.The flip-over arm is movable between a home position adjacent said work surface and an extended position, wherein the flip-over arm may be perpendicular to the work surface. In another alternative, at least a portion of the flip-over arm may extend over the second assembly zone when the flip-over arm is in the extended position. The flip-over assembly may comprise a plurality of movable flip-over arms for moving the truss from the first truss position to the second truss position. The invention preferably includes a lift-out assembly having at least one lift-out arm movable relative to the truss table for moving the truss from the second truss position in the second assembly zone to a finished position spaced from the work surface. The finished position may be above and preferably extends beyond the work surface. The lift-out arm may comprise a plurality of lift-out arm rollers mounted thereon.

TECHNICAL FIELD

The present invention relates in general to an apparatus and method for fabricating structural components. More particularly, this invention concerns an apparatus and method for assembling pre-cut members into trusses and joists.

BACKGROUND OF INVENTION

Prefabricated building components, now widely utilized in the construction industry, are typically assembled at a manufacturing facility and then transported to the job site for incorporation into a building structure. Prefabricated trusses for use as roof or floor supports are assembled from pre-cut wooden chord and web members positioned in abutting relationship and connected together using toothed fastener plates.

Truss assembly devices have been developed for performing this task semi-automatically. The pre-cut wooden members are positioned manually over a support surface and clamped in place, after which connector plates are laid over the abutting joints. The connector plates are then embedded into the members with a gantry or other press to secure the joints on one side. The semi-complete truss is then turned over and similarly secured at the joints on the opposite side.

Various arrangements or truss tables in gantry presses have been employed in the truss assembly devices of the prior art. The prior truss assembly devices, however, have several shortcomings. The clamping methods utilized by the prior machines have been found inadequate in terms of adjustability, positive actuation and the like. In addition, the prior machines have been relatively slow in operation because movement of the trusses on the table during fabrication has been done primarily manually.

There exists a need for a new and improved truss assembly apparatus.

SUMMARY OF THE INVENTION

The invention is for a truss assembly apparatus and a method for assembling a truss utilizing the apparatus. The apparatus comprises a truss table having a work surface divided into a first and second assembly zone. The apparatus further includes first and second clamping assemblies for clamping the truss in the first and second assembly zones. The apparatus includes a flip-over assembly having a flip-over arm movable relative to the truss table for moving the truss from a first truss position in the first assembly zone, wherein a first truss face contacts the work surface, to a second truss position in the second assembly zone, wherein a second truss face contacts the work surface.

The flip-over arm is movable between a home position adjacent said work surface and an extended position, wherein the flip-over arm may be perpendicular to the work surface. In another alternative, at least a portion of the flip-over arm may extend over the second assembly zone when the flip-over arm is in the extended position. The flip-over assembly may comprise a plurality of movable flip-over arms for moving the truss from the first truss position to the second truss position.

The invention preferably includes a lift-out assembly having at least one lift-out arm movable relative to the truss table for moving the truss from the second truss position in the second assembly zone to a finished position spaced from the work surface. The finished position may be above and preferably extends beyond the work surface. The lift-out arm may comprise a plurality of lift-out arm rollers mounted thereon.

The work surface preferably has a plurality of assembly slots therein. The plurality of flip-over arms are aligned with the plurality of assembly slots to allow movement of the flip-over arms from home positions to extended positions. Similarly, the plurality of lift-out arms are aligned with the plurality of assembly slots to allow movement of the lift-out arms.

Flip-over actuators corresponding to the flip-over arms are positioned below the work surface and are interconnected between the truss table and the flip-over arms and are operable to move the flip-over arms. Similarly, the apparatus may include lift-out actuators.

Preferably, the first clamping assembly has a plurality of longitudinally spaced first moveable rails, spaces between the plurality of first moveable rails being aligned with the assembly slots. Similarly, the second clamping assembly preferably has a plurality of longitudinally spaced second moveable rails, spaces between the plurality of second moveable rails being aligned with the assembly slots. The first movable rails are each movable between a first rail home position, wherein the truss is free to move, and a first rail clamped position, wherein the first movable rails contact the truss when the truss is in the first truss position, and wherein the second movable rails are each movable between a second rail home position, wherein the truss is free to move, and a second rail clamped position, wherein the second movable rails contact the truss when the truss is in the second truss position. The first movable rails and the second movable rails are preferably adjacent when the first and second movable rails are in the first and second rail home positions.

Numeral references are employed to designate like parts throughout the various figures of the drawing. Terms such as “left,” “right,” “clockwise,” “counter-clockwise,” “horizontal,” “vertical,” “up” and “down” when used in reference to the drawings, generally refer to orientation of the parts in the illustrated embodiment and not necessarily during use. The terms used herein are meant only to refer to relative positions and/or orientations, for convenience, and are not to be understood to be in any manner otherwise limiting. Further, dimensions specified herein are intended to provide examples and should not be considered limiting.

DESCRIPTION OF A PREFERRED EMBODIMENT

The invention is herein described with reference to the accompanying drawings and is not intended to limit the scope of the claimed invention, but is intended to describe particular embodiments to disclose the best mode of the invention to those skilled in the art.FIGS. 1 and 2show a truss assembly apparatus10for semi-automatic manufacture of prefabricated structural components, particularly wooden trusses and joists. The truss assembly apparatus10comprises a truss table and a table12gantry press14supported on the table for movement there along.

The work surface16of the truss table12is defined by table plates18a-j,which are arranged end-to-end. Table plates18b-I provide working space for assembly of the trusses20and22, while plates18aand18jprovide staging areas for the table gantry press14. The table may be designed to any desired length. The plates18are supported by a plurality of cross-members24which are mounted to the legs26of the table. Each leg26of the table12preferably includes a foot28threadedly attached thereto for height adjustment and leveling of the truss table12(best seen inFIG. 4). Side beams30extend longitudinally beneath the table plates18. Outer rails32extend longitudinally above the table work surface16along the outer edges of the table plates18. Clamping assemblies50are attached to the table12, as shown.

The table gantry press14straddles the work surface16of the truss table12and is supported to run along the length of the table. Gantry wheels34, located in the gantry arms36, roll along the gantry tracks38, which are mounted to the truss table12. A roller press (not shown) located in the gantry body40presses downwardly on the truss table12as the gantry press14passes along the table length.

Referring toFIGS. 2 and 3, truss table12is divided into three longitudinal zones A, B, and C by the clamping assemblies50. In the preferred embodiment, two clamping assemblies50are mounted on each of the support plates18. Assembly zones A and C on each plate18are coincident with the inner and outer jigs52and54of the clamping assemblies50. Intermediate zone B extends between the clamping assemblies50and may be reduced to zero area when the clamping assemblies50are not actuated to clamp a truss20and22, as seen inFIG. 2and as will hereinafter be described. During operation of the truss assembly apparatus10, precut truss chords42and webs44are manually placed in a first truss position21with a first truss face25contacting the table surface in zone A and are secured in place by the clamping assembly50. Toothed connector plates46, which may be stored in the recessed areas48between the outer rails32and the outer longitudinal jigs52, are then placed over the joints between the truss members42and44(as seen inFIGS. 4 and 5) and subsequently embedded in place by passage of the gantry press14over the truss20. The semi-finished truss20is then unclamped, rotated along its longitudinal axis L, and placed in zone C so that the embedded connector plates46are positioned downwardly. The semi-finished truss20, now in the second truss position23, the location of truss22inFIG. 2, with a second truss face27contacting the table surface is clamped in place by the clamping assembly50and secured at the joints on the now upwardly facing side of the truss22with connector plates46embedded therein by another passage of the gantry press14. The now completed truss22is unclamped, removed from zone C, and moved off of the truss table12for storage. During typical use of the truss assembly apparatus10, connector plates46are pressed into trusses20and22in both zones A and C during a single passage of the gantry press14.

Two clamping assemblies50are mounted on each plate18, as shown inFIGS. 1 and 2. The details of the clamping assemblies50are best illustrated inFIGS. 4 and 5. Each clamping assembly50includes an inner longitudinal jig52and an outer longitudinal camber inducing rail or jig54which may be divided into a plurality of longitudinally spaced jigs, as shown. The jigs52and54may be of angle irons oriented as shown. The outer jigs54are attached to the working surface16of the truss table12. Preferably the outer jigs are bolted, or otherwise removably attached, to allow reconfiguration of the jigs as desired. The inner jigs52are slidably mounted to the truss table12. In the preferred embodiment, each of the inner jigs52are mounted to a truck assembly56including an upper jig truck58which is supplied with truck wheels60. The upper truck58is connected, such as with truck spacers62, to a lower jig truck64which is similarly supplied with wheels60. The58and64jig trucks straddle the clamping slot66and the wheels60allow the trucks58and64to roll along the upper and lower surfaces of the table plates18, respectively. The truck spacers62extend through clamping slot66which is formed in the table plate18in a transverse direction across the truss table12as best seen inFIGS. 1 and 2. Other methods of slidable mountings, such as friction mountings, may be used without departing from the spirit of the invention. The jig trucks58and64are attached to a jig actuator, such as the air cylinder68shown. Other actuators may be employed, and may be mounted above or below the table surface, although the actuator design illustrated is preferred for reasons hereinafter explained. The air cylinders68are mounted under the surface of the table plates18by jig actuator brackets. The extendable air cylinder jig rods72are connected to the truck assemblies58and64.

Turning to the clamping assembly in zone A, when the air cylinder68is in a retracted position, as inFIGS. 2 and 4, the inner jig52is positioned near the center of the truss table12in a home position74as shown. As the air cylinder68is actuated, the rod72extends outwardly, moving the truck assembly56, which in turn moves the inner jig52, across the truss tables12along the clamping slot66toward the outer jig54to an extended or clamped position76, as seen inFIG. 5. The air cylinder68will extend to its full length or until the inner jig52encounters and clamps truss into place in zone A. Similarly, a truss22in zone C may be clamped in place by actuation of the air cylinder68, of the clamping assembly in zone C which will move the truck assembly56and inner jig52toward outer jig54. The trusses20and22are unclamped after the gantry press14has embedded the connector plates46into the truss by retraction of the air cylinder to their retracted position, seen inFIG. 4.

Referring back toFIG. 2, each inner jig52is preferably activated independently with a corresponding air cylinder68. The clamping assemblies50act in unison to hold the trusses20and22in place. Where inner jigs52do not encounter a truss, they are extended as far as the air cylinder68will allow. One of the advantages in having a plurality of clamping assemblies50each with a separate inner jig52acting on a single truss20can be seen inFIG. 6. Floor trusses, such as those seen inFIGS. 1-3, have parallel top and bottom chords42. In low-slope roofing applications, however, the members42are not parallel. Sloped chord trusses can be assembled in the present truss assembly apparatus10because the plurality of clamping assemblies50will contact the sloping member43at more than one point on the truss, or along its entire length, as shown. A single longitudinal inner jig which ran the length off the table, such as is common, would only contact the sloped member43at a single location. The inner jigs52of the invention may be pivotally attached to the jig trucks58, if desired, to allow for contact between the jigs and truss members with greater slopes.

Once the gantry press14has embedded the connector plates46into the trusses in zone A and C, the truss in zone C must be lifted out and removed from the table. The truss in zone A must be lifted out, turned over and placed in zone C for completion of the fabrication.

Movement of the trusses is accomplished with the truss movement assembly80, seen inFIGS. 6-8, which comprises a flip-over assembly82and a lift-out assembly100.

The flip-over assembly82is located adjacent zone A and is attached to the lower surface of the truss table12by the truss movement assembly bracket84. The flip-over assembly82comprises an elongate flip-over arm86which is connected at one end by a flip-over arm pivot mounting88to the movement assembly bracket84adjacent the lower surface of the table12. A flip-over arm bracket90pivotally connects the flip-over arm86at a point removed from the flip-over pivot mounting88to one end of the flip-over actuator92. In the preferred embodiment, the flip-over actuator is an air cylinder92having one end pivotally connected to the movement assembly bracket84and the rod end94connected to the flip-over arm bracket90.

While the truss20is being assembled and pressed, the flip-over assembly82is in a home position87, as seen inFIG. 6, wherein the flip-over arm86is positioned not to interfere with assembly of the truss20. The flip-over arm86is pivoted to the extended position89, seen inFIG. 7, by the extension of the rod94of the air cylinder92. The flip-over arm passes through assembly slot78to contact the truss20. The flip-over arm86and actuator are arranged such that the flip-over arm rotates through and preferably past the vertical plane V so that the truss20is rotated longitudinally before falling from the flip-over arm86into zone C. Preferably, at least the end91of arm86moves to a position over zone C, as shown inFIG. 7. The motion and extended position89of the flip-over arm86thus lifts the truss20from zone A, rotates and deposits it such that the connector plates applied to the truss face downwardly in zone C.

Prior to the actuation of the flip-over arm86, the movable inner jigs52are brought to their home position at the center of the table. With the inner jigs so arranged, abutting one another, the area of zone B, evident when the braces are clamping the trusses as inFIG. 5, is reduced greatly, or preferably completely, as inFIG. 6. Many truss assembly mechanisms are unable to greatly reduce or eliminate the area of zone B because of the jig mechanisms disposed in the intermediate zone. The present invention eliminates the area of zone B by mounting the clamping assembly actuators below the table surface and moving the jigs via the small jig trucks actuated through the clamping slots. Because of this feature, the flip-over arm is designed to deposit the truss directly to zone C. In prior art inventions the truss is deposited at least partially into zone B requiring manual relocation of the truss into zone C for further assembly.

The lift-out assembly100is positioned adjacent zone C and is attached to the truss movement assembly bracket84which is mounted to the table12below the work surface16as shown. The lift-out assembly100comprises a lift-out arm102and a lift-out actuator assembly104. The lift-out arm102is seen in its home position103inFIG. 6, wherein the lift-out arm102does not interfere with assembly of the truss22. After completion of assembly of the truss22the lift-out actuator assembly104is activated to raise the lift-out arm102and move it laterally towards the outer rail32at the edge of the table12into the extended or finished position105seen inFIG. 8. The lift-out arm102acts on the truss22after passing from below the table surface16to above the table surface through assembly slot78. The lift-out arm102in turn moves the truss22to a position out of zone C and toward the table edge for removal to a conveyor assembly or to storage. The lift-out arm102is designed to raise the truss22above the outer rail32. Also, the lift-out arm102is preferably designed such that in the extended position the lift-out arm102extends slightly past the outer rails32of the table for ease of removal of the truss from the table.

The lift-out actuator assembly100, in the preferred embodiment, comprises a lift-out actuator, such as the air cylinder106, pivotally connected at one end to the movement assembly bracket84and pivotally attached at the other end to the lift-out power arm108. In the preferred embodiment, the actuator is an air cylinder, but other actuating devices may be employed. The rod end110of the air cylinder106is pivotally attached to the lift-out power arm108through the cylinder bracket112. The lift-out power arm108is pivotally mounted to the movement bracket84at one end and pivotally attached to the lift-out arm102at the other end through the power arm bracket114. Similarly, the support arm116is pivotally connected to the movement assembly bracket84at one end and to the lift-out arm102at the other end through a support arm bracket118. When the air cylinder106is actuated, the rod end110extends outwardly, pivoting the power arm108which in turn lifts and laterally moves the lift-out arm102. The support arm116acts to raise and laterally move the lift-out arm in conjunction with the power arm to the extended position. Actuator assemblies other than the described system may be used without departing from the spirit of the invention.

Preferably, the lift-out arm102has a plurality of rollers120connected thereto to assist the user in moving the truss22off of the lift-out arm102. The lift-out arm102also preferably has a stop block122attached to the lift-out arm102at its innermost end. The stop block122prevents the truss from rolling from the rollers120onto the truss table12.

The truss assembly apparatus described herein is preferably for use in fabricating wooden trusses and joists, although other applications may be obvious to those skilled in the art.

In utilizing the truss assembly apparatus10, precut wooden truss members42and44are arranged in zone A of the truss table12on the working surface16. Simultaneously, a semi-finished truss22is positioned in zone C. The clamping assemblies50are actuated, moving the inner jigs52outward toward the outer jigs54and clamping the trusses20and22between the jigs. End stops and other devices known in the art may be added to assist in the proper arrangement of the truss members. Connector plates46are placed over the joints between the truss members in both zones A and C and are usually manually tapped into the wood so that they will hold their positions during pressing. The gantry press14moves along the length of the table embedding the connector plates46into the wood. The clamping assemblies50are returned to their original home positions74such that the jigs are no longer clamping the trusses. In the home positions, the clamping assemblies preferably have little or no space between them in zone B, at the center of the table. This is, in part, accomplished by positioning the jig actuators68below the table surface16. The lift-out assemblies100are then actuated to move the lift-out arms102into extended positions105, that is, to move the lift-out arms upwardly through the assembly slots78from below the table surface16and engage the truss22thereby raising it out of zone C and moving it toward the outer rails32of the table. Preferably the lift-out arm102include rollers120and move in the extended position105to extend over the outer rails32for ease of removal of the truss22from the truss table12. The lift-out arm102may also include stop blocks122to prevent the truss22from rolling off the lift-out arms102the wrong direction. The lift-out arms102are lowered back into position under the table surface16. The flip-over assemblies82are then activated. The flip-over arms86are rotated from a home position74under the table surface to an extended position76, engaging the truss20and lifting it from zone A while simultaneously rotating it along its longitudinal axis L. The flip-over arms86deposit the truss20in zone C with the connector plates46facing downward. The flip-over arms86are then returned to their home positions74. The order of the steps may vary without departing from the spirit of the invention. The process may be repeated as desired.