The present invention relates to the repair or assembly of pallets, especially block-type pallets, and more particularly, a nail press and method for driving and embedding nails or other fasteners extending from a top surface of each pallet.
Pallets are used frequently in shipping goods and are normally constructed of an upper tier of deck panels. More specifically, a typical pallet is constructed by nailing a series of deck panels to a supporting base. The deck panels form a load support surface upon which goods to be transported are placed.
Such pallets are generally of two types: block-type P1 and stringer-type P2 pallets. A representative stringer-type configuration is seen in accompanying
A standard block-type pallet P1, on the other hand, employs a number of relatively small, rectangular-spaced blocks onto which three-spaced, parallel stringer boards, typically about ¾th-inch thick, are attached lengthwise. A representative block-type configuration is seen in accompanying
Also, it is important to note that the spaces between blocks and stringer boards of a block-type pallet P1 or between stringers of a stringer-type pallet P2 are adapted to receive the tines of conventional forklift trucks. In the course of being moved from place to place with the forklift, these pallets become damaged. Particularly, T1 panels are often hit with the nose of the forks. Although T1 panels are usually made from harder wood, after repeated use, the nails used to fasten the T1 deck panels work loose, particularly if improperly lifted. Also, T1 panels are more prone to be partially or completely broke if the forks are not properly positioned before lifting. If these problems are not corrected, the random, upstanding nails and broken panels will damage the goods loaded and/or removed from these pallets. Although the difference in board thicknesses and nail-to-board height difference may seem relatively small, it often causes substantial property damage and loss by tearing or scratching the packaging, goods and/or equipment stacked on the pallet.
As a result of its configuration and construction, during repair or furbishing of block-type pallets P2, a problem often arises if a T1, or even T4 panel is replaced with a board not fully cured. Specifically, the width of the T1 panel is about ¾th-inch thick when freshly cut. After curing, that same panel typically shrinks in thickness to about 11/16th-inch. Therefore, if a T1 panel is replaced with another not fully cured, it is often slightly thicker than the other deck panels. Also, a replacement panel may be accidentally cut thicker or thinner than standard board thicknesses. Whatever the reason, it has been found that this replacement board-thickness difference often causes a serious problem. That replacement board thickness difference is shown, for example, by spacing d2 in accompanying
While more pronounced with block-type pallets, the problem of raised or extended fasteners and replacement board thickness differences also occurs with stringer-type pallets.
When pallets having the problems described are being furbished and passed through a pallet nail press such as that described in U.S. Pat. No. 5,375,315, the top anvil may hit the top surface of each T1 and T4 panels, but, if a T1 panel, for example, is thicker than the other deck panels for the reasons stated, that same anvil will never completely contact the top surface of adjacent, and relatively lower, T2 and T3 panels. Since they are made of hardwood, these T1 and T4 panels are less forgiving and compress only slightly as compared to the adjacent T2 and T3 panels made from relatively softer woods. As a result, nails extending above the surface of the thinner panels are not rendered flush with the pallet top surface, as should be the case after passing through the nail press. Also, if one of the stringer boards SL, SM or SR is slightly bowed downward between blocks, a new replacement T1 or T4 panel may extend even higher above its nearby T2 and T3 panels, further exacerbating the problem of varying nail heights above the pallet top surface after compression with a nail press.
Notably, with existing, automated pallet nail presses, it is difficult to adjust the compression force in the press to contact these lower areas across the pallet upper surface. If too much compression is applied to force complete press-to-pallet contact, damage to the thicker areas of the pallet and/or blocks therebeneath occurs.
In the field of pallet manufacturing, automation is known, as seen for example in the automatic apparatus and methods of Buck U.S. Pat. Nos. 6,736,591 and 6,430,800, or the earlier apparatus of Pope's U.S. Pat. No. 5,555,617. There are also known methods and equipment for removing components to pallets such as the board and stringer removal apparatus of Minick's U.S. Pat. No. 6,829,822 and Beane's U.S. Pat. No. 6,032,351. For lumber related applications, Runnebaum's U.S. Pat. No. 5,547,002 discloses a variety of framed press machinery. And, in a completely different context, Ilies' U.S. Pat. No. 6,763,564 teaches a method and apparatus for driving fasteners into an electric fan assembly. But, none of the foregoing addressed automating pallet furbishing, particularly the driving of fasteners into block-type pallet upper surfaces, as well as their stringer design counterparts having a less than planar top or uppermost surface.
For these and other reasons, it is an objective of this invention to address the aforementioned pallet repair shortcomings and provide a more universal, dynamic nail press and method that will accommodate varying panel thicknesses, bowing, warping, and other imperfections for pressing down all fasteners that otherwise extend above its uppermost surface. The preferred press described herein for embedding outwardly extended or loosened nails and other fasteners, includes a press having an anvil with a plurality of anvil plates resiliently attached to a frame with a hammer beam movably positioned in a vertical space alignment with the several anvil plates. A drive is used for advancing the hammer beam sufficiently away from a conveyor system and preferably toward the anvil plates for compressing the top-deck panels therebetween to more completely embed into the pallet upper panels any extended fasteners. Alternately, if the pallet is sufficiently separated from the underlying conveyor, the resiliently attached anvil plates can be lowered down and over the pallet proper for embedding any and all raised fasteners from the pallet's uppermost surface.
For this and other reasons, this invention represents a significant advantage over other automated machines, even the pallet nail press and method of Griffith, et al., U.S. Pat. No. 5,375,315.
An object of the present invention is to provide a pallet nail press that quickly, yet easily and efficiently engages the whole top surface of a pallet's upper panel deck with sufficient force to embed any and all raised fasteners without damaging the panels comprising that upper deck and/or the pallets structural integrity.
Another object of the invention is to provide a press that easily adjusts to pallet imperfections often encountered with repairing pallets, especially block-type pallets.
A still further objection of the invention is to provide a press that can accommodate pallet panels of varying wood types, thicknesses, shapes and styles.
To achieve the foregoing and other objects and in accordance with the purpose of the invention embodied and broadly described herein, an embodiment of the invention preferably includes a pallet nail press having a main support frame with an anvil having a plurality of anvil plates resiliently attached. A hammer beam is movably positioned within said frame in a substantially vertical space alignment with the plurality of anvil plates. That hammer beam is driven by a mechanism for advancing the beam linearly toward said anvil plates, preferably by raising the pallet. There, the pallet top-deck panels will be pressed against the resiliently attached plates of the anvil to more completely and effectively embed nails or fasteners.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.
To describe the present preferred embodiment of the invention, reference shall be made to accompanying drawings in which:
Referring first to
As described earlier, the upper deck panels are generally referred to as T1 panels along the pallet widths at both the front FP and rear RP ends of the pallet P1. Often immediately adjacent, and sometimes in contact with each end deck panel T1 is an internal deck panel, each designated T2, that extend at least partially over the end blocks B1 beneath stringer boards SL and SR, and over the center block B2 with its corresponding stringer SM.
In almost all cases, bottommost pallet boards D connect the lower sections to the end and center blocks, i.e. B1-B2-B1, B2-BC-B2 and B1-B2-B1, respectively, for structural integrity. When completed, the foregoing arrangement forms a pair of forklift openings O into which tines of a lift machine may be guided to raise and lower the load of goods and/or equipment situated on the pallet.
As described above,
The other, longer nails can also work their way out of their respective fastener holes and rise ever so slightly above the pallet top. It is preferred, therefore, that a pallet being readied for first use, or for reuse after repair or refurbishing, have all of its fasteners pressed down into the uppermost surface of the deck panels. While distance d1 can vary depending on the extent to which a fastener rises above the pallet upper plane, a pallet nail press is needed that can accommodate different pallet deck panel thicknesses and/or different nail corrective heights.
In accompanying
A pallet stop assembly 21 is positioned between the terminal end of infeed conveyor 11 and a pallet press conveyor 20. That stop assembly 21 provides a restriction to maintain a pallet P1 or P2 on the infeed conveyor 11 while another pallet is being worked on in the pallet nail press 10. The indexing pin 21A of the stop assembly 21 raises and retracts via a piston and cylinder assembly engagement with each duly positioned pallet P1 or P2, as described hereafter.
In the first preferred embodiment, the pallet press conveyor 20 has spaced parallel tracks 20A and continuous conveyor chains 20B thereon for extending into and through the pallet nail press 10. A movable pallet indexing pin (not shown), similar to indexing pin 21, extends in the pallet nail press, between the pallet press conveyor 20, and operates in sequence with indexing pin 21 to stop and hold conveyed pallets in position for compression.
The pallet nail press 10 has a support frame defining pairs of spaced vertical support beams 23, 24 with respective upper 23A, 24A and lower cross supports 23B, 24B. The vertical support beams 23, 24 interconnect via the engaging longitudinal support beams 25 and 26, respectively. Pairs of air bags 27, 28 are positioned on the lower cross support 23B, 24B on circular mounts defined by upper and lower mounting plates 29, 30 for raising same in the general direction of raising arrow “R” in
Preferably, multiple hammer I-beams 34, 35, and 36 extend in a spaced, parallel relation between and on top of lift beams 31 and 32 completing the movable portion of this particular pallet nail press 10 embodiment. A plurality of safety stops 31A, 32A may extend from and secure to each vertical support pair 23B, 24B to prevent unrestricted vertical travel of hammer I-beams 34, 35 and 36, should a pallet be improperly and/or erroneously positioned in the press.
In contrast to the nail press of U.S. Pat. No. 5,375,315, among other changes, the prior system's plurality of stationary, anvil I-beams are replaced with anvils having a plurality of plate pairings 38A-38B, 39A-39B and 40A-40B, respectively (hereinafter referred to in combination as “38A/B”, “39A/B” and “40A/B,” respectively). As better seen in accompanying
As shown in
Continuing to refer to
In the preferred embodiment, the resiliency of the aforementioned anvil plates 38A/B, 39A/B and 40A/B is critical. Also, these resilient plates are preferably suspended below their correspondingly adjacent fixed anvil segments F/C/R38, F/C/R39 and F/C/R40, which are positioned at and above the respective pallet blocks B1, B2 and BC, as discussed above, to sufficiently accommodate different thicknesses of the top-deck panels, particularly between adjacent T1 and T2 panels or adjacent T3 and T4 panels, during refurbishing. It is important note the relative distance or thickness difference d2 between the newly replaced T1 panel and the neighboring, preexisting T2 panel in
As previously stated, if these same T1 or T4 boards run slightly thicker than their neighboring pallet top-deck panels, for any of the several reasons discussed, there would be no resiliency in the fully-fixed, continuous anvil beam of the prior art. Without the “floating” anvil plate resiliency, the prior art press anvil beam might never contact the top surface to every top-deck panel. In the preferred embodiment, the relative distance between the lowermost plane (i.e. contact surface) of fixed anvil segment F38 and the lowermost plane to the immediately adjacent, resilient anvil plate 38A is shown as d3 in accompanying
By resiliently suspending the anvil plates below the fixed anvil beam segments, to be substantially aligned between adjacent block pairs for each set of longitudinally-extended blocks, the present invention will enable greater T2 and T3 board contacting when thicker T1 or T4 panels are present. With spring loading, as is preferred herein, these same “floating” anvil plates resiliently mounted to the corresponding anvil support member 138, 139 and 140 will be able to better provide resistance for pushing in any and all raised nail heads and stems, but not so hard as to possibly break one or more of the underlying pallet stringer boards SL, SM or SR.
Preferably, at least two pallet exit stop pin assemblies 44 are spaced to be within the width of the standard pallet and secured to and extend downwardly from upper support beams 24A.
In operation, a block-type pallet P1 is shown in cross-section entering the pallet nail press 10 at
Once the upward cycle and compression of this press has been completed, air bags 27, 28 deflate, the hammer beams 34, 35 and 36 return, anvil plate pairs 38A/B, 39A/B and 40A/B return to the offset position (relative to the fixed anvil segments F/C/R38, F/C/R39 and F/C/R40) and registration pins 46 retract allowing the repaired pallet to once more engage with the pallet press conveyor 20 and exit the pallet nail press 10. After that first pallet has cleared electronic sensor 50, the retraction of indexing pin 21 is activated and the next pallet is conveyed into the press for repeating the aforementioned process step cycle. The entire cycle time is relatively short, i.e. about 3 to 4 seconds.
Notably,
Finally, it is important to note that accompanying
Still further, the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Number | Name | Date | Kind |
---|---|---|---|
3376808 | Beckett et al. | Apr 1968 | A |
3557439 | Dykeman | Jan 1971 | A |
3823861 | Jureit et al. | Jul 1974 | A |
3908885 | Scott | Sep 1975 | A |
4429629 | Leonard | Feb 1984 | A |
4669184 | Castillo | Jun 1987 | A |
4998336 | Papsdorf | Mar 1991 | A |
5285720 | Wright | Feb 1994 | A |
5375315 | Griffith et al. | Dec 1994 | A |
5547002 | Runnebaum | Aug 1996 | A |
5555617 | Pope | Sep 1996 | A |
6032351 | Beane | Mar 2000 | A |
6763564 | Iles | Jul 2004 | B2 |
6829822 | Minick | Dec 2004 | B1 |
Number | Date | Country |
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9215057 | Feb 1994 | AU |
Number | Date | Country | |
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20080295708 A1 | Dec 2008 | US |