ADJUSTABLE BAFFLE AND SECURE ATTACHMENT

RELATED APPLICATION

[001] This patent application claims the benefit of United States Provisional Patent Application, Serial No. 62/350,996 that was filed on June 16, 2016, for an invention titled IMPROVED ASPHALT MILLING ATTACHMENT WITH ADJUSTABLE BAFFLE AND SECURE ATTACHMENT, which is incorporated herein by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[002] The present invention relates to systems and methods for milling asphalt. More specifically, the present invention relates to improved systems and methods that provide both an adjustable baffle and secure attachment.

[003] Various exemplary embodiments of the present invention are described below. Use of the term "exemplary" means illustrative or by way of example only, and any reference herein to "the invention" is not intended to restrict or limit the invention to exact features or steps of any one or more of the exemplary embodiments disclosed in the present specification. References to "exemplary embodiment," "one embodiment," "an embodiment," "various embodiments," and the like, may indicate that the embodiment(s) of the invention so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase "in one embodiment," or "in an exemplary embodiment," do not necessarily refer to the same embodiment, although they may.

2. The Relevant Technology

[004] Pavement milling is currently employed to remove existing pavement for reconstruction, resurfacing, or reuse. Known pavement milling assemblies are either self-propelled or are attachments that are connected to a drivable construction vehicle, such as a front end loader, forward of the wheels or tracks thereof. The construction vehicle (hereinafter sometimes referred to as the "host vehicle") then propels the pavement milling attachment over pavement preselected for milling.

[005] Early pavement milling attachments have had drawbacks. However, some of those drawbacks have been resolved recently, but other drawbacks remain unsolved.

[006] For example, early pavement milling assemblies reliably retained the pavement material being milled only when the depth of the cut of the pavement material to be milled was set at the maximum milling depth attainable. Otherwise, such early pavement milling assemblies permitted dislodged paving material that was being pulverized into granules to escape from the milling assembly, becoming lost or unusable. However, U.S. Patent No. 8,177,456 issued to Haroldsen ("Haroldsen '456") resolved this drawback with a pavement milling assembly that allows pavement being milled to remain confined within a milling region circumscribed by a milling frame. The teachings of the Haroldsen '456 reference are incorporated herein by this reference.

[007] Also, most early pavement milling attachments are supported in part on a wheel, wheels, or a skid plate that upholds the front end of the pavement milling attachment on the surface of the pavement to be milled in the direction of the forward travel of the pavement milling attachment itself. This support of the early pavement milling attachments on a relatively small area of pavement about to be milled determined the depth at which milling occurred. Unfortunately, as the propelling host vehicle drove these early pavement milling attachments from behind, it was difficult to precisely control the depth at which pavement milling occurred. Maintaining the desired milling depth was resolved by U.S. Patent No. 8,398,176 issued to Haroldsen et al. ("Haroldsen Ί76"), wherein a rotating hood provided both depth control and bit access by rotating the hood to lift or lower the milling drum. The teachings of the Haroldsen '176 reference are incorporated herein by this reference.

[008] Nevertheless, drawbacks are still being encountered by pavement milling attachments. For example, existing pavement milling attachments are often damaged by large chunks of pavement or oversized rocks that are dislodged during milling or such large chunks of pavement or oversized rocks may become wedged, causing milling stoppage. Such damage and/or wedged clogging of the milling drum can affect the uniformity of the milling or cause significant down time to dislodge wedged material and/or to repair the damage caused.

[009] Also, the propelling host vehicles have experienced difficulty in maintaining the connection between the host vehicle and the pavement milling attachment, causing the connection to drift, to adjust, or to be temporarily lost. If the depth of pavement milling is to be maintained constant, the occurrence of such exigencies require repeated corrective adjustments and accommodations to the host vehicle and to the attachment between the host vehicle and the pavement milling attachment. The efficiency of the milling process may be compromised costing time and expense if the connection of the host vehicle to the pavement milling attachment is not secure.

[0010] Accordingly, a need exists for an improved system and method for resolving these drawbacks while maintaining depth control and bit access. Such improved systems and methods are disclosed herein.

BRIEF SUMMARY OF THE INVENTION

[0011] The embodiments of the present disclosure have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available pavement milling attachments.

[0012] According to one aspect of the present disclosure, a pavement milling attachment upholds a rotating pavement milling drum as the pavement milling attachment travels over pavement preselected for milling. The pavement milling attachment includes a sled-like portion with laterally- separated left and right runners, each of which has a lead end oriented toward the front of the pavement milling attachment and a lower face configured for sliding travel on the surface of the pavement.

[0013] A milling frame is mounted between the runners. The milling frame circumscribes a milling region in which rotation of the milling drum dislodges pavement located in the path of forward travel of the pavement milling attachment, pulverizes dislodged pavement, and deposits pulverized pavement to the rear of the milling drum. The milling frame itself includes left and right milling region sidewalls that extend upwardly from the floor of the pavement milling attachment on opposite sides of the milling region and a discharge baffle between the milling region sidewalls at the rear of the milling region. The proximity of the discharge baffle to the milling drum is adjustable so that a desired space between the milling drum and discharge baffle, needed for optimum pulverization, is maintained as the milling depth is adjusted by raising and lowering the milling drum. [0014] The discharge baffle pivots about hinge pins and has slide pins and slot pins that travel along curved slots in the milling region sidewalls at the rear of the milling region. The pivoting of the discharge baffle may be controlled hydraulically. In this manner, the discharge baffle may be moved forward and rearward depending on and coordinated with the cutting depth of the milling drum to maintain the desired space between the milling drum and the discharge plate. The discharge baffle also may be pivoted out of the way preventively to allow a large chunk of pavement or an oversized rock to pass through and be discharged without wedging between the milling drum and the discharge baffle. This preventive pivoting of the discharge baffle may be initiated manually or may be automatically initiated if a threshold resistance in the rotation of the milling drum is sensed and maintained for a predetermined amount of time.

[0015] The hood encasing the milling drum may have a bit access assembly comprising a bit access hatch that opens to permit access to the milling bits and to pavement chunks or oversized rocks that may get wedged between the hood and the milling drum. In the past, the bit access hatch has had one or more latches to secure the bit access hatch to the hood. However, when a large rock or other hard object passed through the milling chamber, the obstruction could break the latch(es) and bend the bit access hatch or hood. With some embodiments of the present disclosure, extendable/retractable cylinders such as hydraulic cylinders, pneumatic cylinders, and the like may be used as a component part of the bit access assembly. For example, hydraulic clamping by the same hydraulic cylinders that are used to open the bit access hatch may be used. In this manner, the bit access hatch is held closed with a predetermined pressure setting that is below what otherwise would bend or break the bit access hatch. If any oversized obstruction (rock or pavement chunk, for example) is encountered and the predetermined pressure is exceeded, the bit access hatch pops open momentarily to allow the obstruction to pass through, and then automatically resets and closes so the bit access hatch is not damaged. In this manner, significant down time is avoided.

[0016] According to another aspect of the present disclosure, a pavement milling attachment may include a connection securing assembly that secures the host vehicle bucket within the pavement milling attachment's bucket slot. The connection securing assembly may comprise one or more retention tethers of a length sufficient to wrap around the backside of the host vehicle bucket. Each retention tether, such as a chain or metal cable, may have a latching hook (or any other suitable fastener) at a distal end and may be connected to an actuator at a proximal end. To secure the host vehicle bucket within the bucket slot, each retention tether extends about the backside of the bucket and the latching hook captures the upper edge of the bucket. Then each of the retention tethers is tightened by activating the actuator (such as shortening the length of a hydraulic cylinder) and pulling the retention tether taut. In this manner, the connection between the pavement milling attachment and the host vehicle is maintained against drift, slippage, adjustment, or disengagement. The retention tethers may be removed rapidly and easily by reversing the actuator to loosen the retention tethers so that the latching hooks or other fasteners will release. Such retention tethers should have the strength to hold the bucket against the milling attachment. Chains, metal cables, and the like may be used, particularly if they have minimal stretch when pulled taut.

[0017] Moreover, retention chains or cables securing the bucket within the bucket slot may be held hydraulically by the actuator rather than a load binder. If held by a load binder only, should the host vehicle operator curl the bucket downward while the milling attachment is on the ground, the leverage of the bucket may exert enough force to break the chain, cable, and/or the load binder. However, with the retention chain or cable hydraulically actuated, the actuator may allow the retention chain or cable to give so that the strength of the retention chain or cable is not exceeded. Again, significant down time may be avoided by preventing the retention chain, cable, and/or the load binder from breaking.

[0018] The teachings of the present disclosure provide a pavement milling attachment that allows pavement being milled to remain confined in a controlled milling region, where full and uniform pavement particle pulverization can be effected. As a result, installed pavement can be milled into any desirable size. Material size is controlled by limiting the amount of pavement released at the rear of the pavement milling attachment. The pavement milling attachment of the present disclosure also improves control of milling depth by controlling and stabilizing the milling space to effect full pulverization at the desired milling depth and by maintaining a secure connection between the pavement milling attachment and the host vehicle.

[0019] These and other features of the present disclosure will become more fully apparent from the following description and the related drawings. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0020] In order that the manner of obtaining the above-recited and other features and advantages of the pavement milling attachment of this disclosure will be readily understood, a description is rendered with reference to exemplary embodiments which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments and are not therefore to be considered to be limiting of its scope. The accompanying drawings are:

[0021] FIG. 1 is a perspective view of a prior art pavement milling attachment showing the connection to a host vehicle;

[0022] FIG. 2 is a section view of the prior art pavement milling attachment of FIG. 1 showing the proximity of the milling drum and the discharge baffle;

[0023] FIG. 3 is a side view of an exemplary embodiment of a pavement milling attachment of the present disclosure connected to a host vehicle bucket and with the left sidewall removed to better show the device in a shallow depth configuration;

[0024] FIG. 4 is a side view of the exemplary embodiment of the pavement milling attachment in FIG. 3 with the left sidewall removed to better show the device in a full depth configuration;

[0025] FIG. 5 is a cut-away perspective view of the inside of the left sidewall of an exemplary embodiment of the pavement milling attachment showing the discharge baffle;

[0026] FIG. 6 is a cut-away perspective view of the outside of the right sidewall of an exemplary embodiment of the pavement milling attachment showing an actuator for controlling the adjustment of the discharge baffle;

[0027] FIG. 7 is a cut-away perspective view of an exemplary bit access hatch closed over the milling drum hood of an exemplary embodiment of the pavement milling attachment;

[0028] FIG. 8 is a cut-away perspective view of the exemplary bit access hatch of FIG. 7 opened to reveal access to the milling bits; and

[0029] FIG. 9 is a side view of another exemplary embodiment of a pavement milling attachment with the left sidewall present 3 showing the connection securing assembly engaging a host vehicle bucket within a bucket slot.

REFERENCE NUMBERS

host vehicle 10 pavement milling attachment 12

pavement 14 curb 16 sled-like portion 18 superstructure 20

milling drum 21 milling drum hood 22

drive train hood 24 left runner 26

right runner 28 lead end 30

discharge baffle 32 fragments 34

milling region 36 milling chamber 37

rear wall 38 sidewalls 40

exit gate 42 upper edge 44

hinges 46 apertures 48

discharge bed 49 upper baffle 50

lower baffle 52 hinge pins 53

slide pins 54 curved slots 56

baffle actuator 58 slot pins 60

upper slots 62 bit access hatch 64

milling bits 65 hydraulic cylinder(s) 66

connection securing assembly 70 host vehicle bucket 72

bucket slot 74 retention chains 76

latching hook 78 actuator 80

eyelet end 81 upper edge 82

depth D forward motion M

rotation R

DESCRIPTION OF THE INVENTION

[0030] Exemplary embodiments of the pavement milling attachment of this disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the exemplary embodiments, as generally described and depicted in the figures, could be arranged and designed in a wide variety of different configurations. Thus, the following description of the exemplary embodiments of the present disclosure, as represented in the figures, is not intended to limit the scope of the invention, but is merely representative of exemplary embodiments. [0031] While the various aspects of exemplary embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

[0032] In this application, the phrases "connected to", "coupled to", and "in communication with" refer to any form of interaction between two or more entities, including mechanical, capillary, electrical, magnetic, electromagnetic, pneumatic, hydraulic, fluidic, and thermal interactions.

[0033] The phrases "attached to", "secured to", and "mounted to" refer to a form of mechanical coupling that restricts relative translation or rotation between the attached, secured, or mounted objects, respectively. The phrase "slidably attached to" refers to a form of mechanical coupling that permits relative translation, respectively, while restricting other relative motions. The phrase "attached directly to" refers to a form of securement in which the secured items are in direct contact and retained in that state of securement.

[0034] The term "abutting" refers to items that are in direct physical contact with each other, although the items may not be attached together. The term "grip" refers to items that are in direct physical contact with one of the items firmly holding the other. The term "integrally formed" refers to a body that is manufactured as a single piece, without requiring the assembly of constituent elements. Multiple elements may be integrally formed with each other, when attached directly to each other from a single work piece. Thus, elements that are "coupled to" each other may be formed together as a single piece.

[0035] Referring now to FIGS. 1 and 2, a prior art pavement milling attachment is depicted. FIG. 1 is a perspective view of a host vehicle 10 attached to the rear of a prior art embodiment of a pavement milling attachment 12. The host vehicle 10 causes the pavement milling attachment 12 to travel in a forward motion M indicated in order to mill a portion of pavement 14 that is located adjacent to a concrete curb 16.

[0036] The pavement milling attachment 12 includes a sled-like portion 18 that upholds a complex superstructure 20 that includes the active components of pavement milling attachment 12. These active components of pavement milling assembly 12 include a pavement milling drum 21 and a drive train operably connected therewith to cause rotation thereof. Each is concealed in FIG. 1, respectively, by a milling drum hood 22 and by a drive train hood 24. Along with the active components of superstructure 20, the milling drum hood 22 and drive train hood 24 are ultimately carried during travel of pavement milling attachment 12 by sled-like portion 18.

[0037] The sled-like portion 18 travels on the surface of pavement 14 on a left runner 26 that is fully visible in FIG. 1 and on a right runner 28 (shown in FIG. 2). Left runner 26 and right runner 28 are laterally separated from each other by a distance that is approximately equal to or greater than the width of superstructure 20. Left runner 26 has an upwardly turned lead end 30 that is oriented toward the front of the sled-like portion 18. Similarly, right runner 28 has an upwardly turned lead end 30 that is also oriented toward front of the sled-like portion 18.

[0038] By contacting the surface of pavement 14 over a relative extensive area, left runner 26 and right runner 28 together function to average out irregularities in the surface of pavement 14 and maintain the rotating pavement milling drum 21 inside pavement milling attachment 12 in a relatively invariant vertical relationship to pavement 14. This results in a uniform depth to the pavement milling effected by the travel of pavement milling attachment 12 caused by the host vehicle 10, so long as the connection between the pavement milling attachment 12 and host vehicle 10 does not drift, adjust, or become disengaged. Left runner 26 and right runner 28 also function to hold in place the portions of pavement 14 located directly there beneath, which the rotating pavement milling drum 21 inside pavement milling attachment 12 dislodges and pulverizes the portion of pavement 14 between left runner 26 and right runner 28. This contributes to the creation of straight sides to the trench cut into pavement 14 by the pavement milling action of pavement milling attachment 12 in traveling there over.

[0039] FIG. 2 is a cross- sectional elevation view of the prior art pavement milling attachment 12 FIG. 1. For clarity, the drive train and drive train hood 24 have been omitted FIG. 2 and the remaining figures so not to obscure the features of the present disclosure. Milling drum 21 engages the pavement 14 in milling rotation R and can be seen enclosed by milling drum hood 22. Milling drum 21 accordingly cuts a trench in a milling region 36 through installed pavement 14 to a milling depth D, which may be adjusted by changing the height of milling drum 21 within pavement milling attachment 12. The milling drum hood 22 and a discharge baffle 32 retain loose pavement particles or fragments 34 within a milling chamber 37 to effect full pulverization.

[0040] The discharge baffle 32 prevents the escape of dislodged fragments 34 of pavement 14 from the rear of pavement milling sled 18. [0041] Discharge baffle 32 includes a rear wall 38 that is rigidly secured between right and left milling region sidewalls 40. Rear wall 38 does not extend as far downwardly as do the milling region sidewalls 40. The adjustable portion of discharge baffle 32 is a pulverized pavement exit gate 42. The exit gate 42 depends by its upper edge 44 on a pair of hinges 46 that are attached to the rearward side of rear wall 38. Consequently, the exit gate 42 can be pivoted about the hinges 46. In this manner, the exit gate 42 may be positioned to achieve discrete clearances by engaging apertures 48 with pins (not shown) cooperating to retain the exit gate 42 in one of the predetermined orientations. The pavement fragments 34 are deposited in a discharge bed 49 that is leveled as exit gate 42 passes over the discharged pavement fragments 34.

[0042] With reference to FIGS. 3 and 4, side elevation views of an exemplary embodiment of the pavement milling attachment 12 of the present disclosure are depicted in a shallow milling configuration (FIG. 3) and a full depth milling configuration (FIG. 4). The pavement milling attachment 12 upholds a rotating pavement milling drum 21 as the pavement milling attachment 12 travels over pavement 14 (not shown, but as seen in FIGS. 1 and 2) preselected for milling. The pavement milling attachment 12 includes a sled-like portion 18 with laterally- separated left and right runners 26, 28 (not shown, but as seen in FIGS. 1 and 2), each of which has a lead end 30 (not shown, but as seen in FIGS. 1 and 2) oriented toward the front of the pavement milling attachment 12 and a lower face configured for sliding travel on the surface of the pavement 14.

[0043] A milling frame is mounted between the runners 26, 28. The milling frame circumscribes a milling region 36 in which rotation of the milling drum 21 dislodges pavement 14 located in the path of forward travel of the pavement milling attachment 12, pulverizes dislodged pavement 14, and deposits pulverized pavement fragments 34 into the discharge bed 49 to the rear of the milling drum 21. (See FIG. 2). The milling frame itself includes left and right milling region sidewalls 40 that extend upwardly from the floor of the pavement milling attachment 12 on opposite sides of the milling region 36 and a discharge baffle 32 between the milling region sidewalls 40 rearward of the milling region 36. The proximity of the discharge baffle 32 to the milling drum 21 is adjustable so that a desired space between the milling drum 21 and discharge baffle 32, needed for optimum pulverization, is maintained as the milling depth D is adjusted by raising and lowering the milling drum 21.

[0044] The discharge baffle 32 has an upper baffle 50 and a lower baffle 52 that overlap and telescopically slide to adjust the height of the discharge baffle 32 as the discharge baffle 32 pivots about hinge pins 53. The lower baffle 52 has slide pins 54 that travel along lower slots, such as the curved slots 56 depicted in the milling region sidewalls 40 rearward of the milling region 36. The pivoting of the discharge baffle 32 may be controlled by a baffle actuator 58 (such as the hydraulic cylinder shown) that moves the upper baffle 50 by sliding one or more slot pins 60 within one or more upper slots 62. In this manner, the discharge baffle 32 may be moved forward and rearward depending on and coordinated with the cutting depth D of the milling drum 21 to maintain the desired space between the milling drum 21 and the discharge baffle 32. The discharge baffle 32 also may be pivoted out of the way preventively (by fully extending the baffle actuator 58) to allow a large chunk of pavement 14 or an oversized rock to pass through and be discharged without wedging between the milling drum 21 and the discharge baffle 32. This preventive pivoting of the discharge baffle 32 may be initiated manually or may be automatically initiated if a threshold resistance in the rotation of the milling drum 21 is sensed and maintained for a predetermined amount of time.

[0045] FIGS. 5 and 6 depict the adjustable discharge baffle 32 and the slidable engagement of the slide pins 54 within the lower slots depicted as curved slots 56. FIG. 5 is a cut-away perspective view of the inside of the left sidewall 40 and FIG. 6 is a cut-away perspective view of the outside of the right sidewall 40.

[0046] As shown in FIGS. 3, 4, 7, and 8, the hood 22 encasing the milling drum 21 may have a bit access assembly that includes a bit access hatch 64 that opens to permit access to the milling bits 65 and to pavement chunks or oversized rocks that may have wedged between the hood 22 and the milling drum 21 within the milling chamber 37. The bit access assembly may have one or more extendable/retractable cylinders such as hydraulic cylinders 66 to secure the bit access hatch 64 to the hood 22. If any oversized obstruction (rock or pavement chunk, for example) is encountered, the hydraulic cylinder(s) 66 pop open the bit access hatch 64 momentarily, and then automatically reset and close the bit access hatch 64 so the hood 22 and/or the bit access hatch 64 are not damaged and the obstruction may rapidly pass through the milling chamber 37. Additionally, the bit access hatch 64 may be opened and closed hydraulically for maintenance of the milling bits 65 or cleaning.

[0047] FIG. 9 shows a connection securing assembly 70 attached to the rear of the pavement milling attachment 12 that secures a host vehicle bucket 72 within the pavement milling attachment's bucket slot 74. The connection securing assembly 70 may comprise one or more retention tethers such as retention chains 76 of a length sufficient to wrap around the backside of the host vehicle bucket 72, each retention chain 76 having a latching hook 78 (or any other suitable fastener) at one end and being connected to an actuator 80 at the other end. To secure the host vehicle bucket 72 within the bucket slot 74, each retention chain 76 extends through an opening in an eyelet end 81 (to restrain the lateral displacement of the retention chain 76) and about the backside of the bucket 72. Attached to the end of each retention chain 76 is a latching hook 78 that captures the upper edge 82 of the bucket 72. Then each of the retention chains 76 is tightened by activating the actuator 80 (such as shortening the length of a hydraulic cylinder) and pulling the retention chain 76 taut against the bucket 72. In this manner, the connection between the pavement milling attachment 12 and the host vehicle 10 is maintained against drift, slippage, adjustment, or disengagement. The retention chains 76 may be removed rapidly and easily by reversing the actuator 80 to loosen the retention chains 76 so that the latching hooks 78 will release.

[0048] Additionally, because the bucket 72 may exert leveraged force upon the retention chain(s) 76 sufficient to break the retention chain(s) 76, the actuator 80 may be pre-set to a threshold pressure that will allow the retention chain(s) 76 to give so that the strength of the retention chain(s) 76 is/are not exceeded while maintaining a taut securement of the bucket 72. When the force of the bucket 72 is reduced below the threshold pressure, the actuator 80 automatically resets and draws the retention chain(s) 76 taut.

[0049] The teachings of the present disclosure provide a pavement milling attachment 12 that allows pavement 14 being milled to remain confined in a controlled milling chamber 37, where full and uniform pavement fragment 34 pulverization can be effected. As a result, installed pavement 14 may be milled into fragments 34 of any desirable size. Milled pavement fragment 34 size is controlled by limiting the amount of pavement fragments 34 released into the discharge bed 49 at the rear of the pavement milling attachment 12, and this is done by controlling the space between the milling drum 21 and the discharge baffle 32. The pavement milling attachment 12 of the present disclosure also improves control of milling depth D by controlling and stabilizing the milling space to effect full pulverization at the desired milling depth D and by maintaining a secure connection between the pavement milling attachment 12 and the host vehicle 10. [0050] Those skilled in the art will appreciate that the present embodiments are exemplary only and that the individual components of each improvement for the pavement milling attachment 12 may be configured in any of a number of ways and may be included or not within the pavement milling attachment 12.

[0051] For exemplary methods or processes of the invention, the sequence and/or arrangement of steps described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal arrangement, the steps of any such processes or methods are not limited to being carried out in any particular sequence or arrangement, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and arrangements while still falling within the scope of the present invention.

[0052] Additionally, any references to advantages, benefits, unexpected results, or operability of the present invention are not intended as an affirmation that the invention has been previously reduced to practice or that any testing has been performed. Likewise, unless stated otherwise, use of verbs in the past tense (present perfect or preterit) is not intended to indicate or imply that the invention has been previously reduced to practice or that any testing has been performed.

[0053] Exemplary embodiments of the present invention are described above. No element, act, or instruction used in this description should be construed as important, necessary, critical, or essential to the invention unless explicitly described as such. Although only a few of the exemplary embodiments have been described in detail herein, those skilled in the art will readily appreciate that many modifications are possible in these exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the appended claims.

[0054] In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. Unless the exact language "means for" (performing a particular function or step) is recited in the claims, a construction under Section 112, 6 ^th paragraph is not intended. Additionally, it is not intended that the scope of patent protection afforded the present invention be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself.

[0055] While specific embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise configuration and components disclosed herein. Various modifications, changes, and variations which will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and systems of the present invention disclosed herein without departing from the spirit and scope of the invention.

[0056] Those skilled in the art will appreciate that the present embodiments may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and 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.