One or more rack modules may be semi-permanently attached to a deck to provide storage for material. Each rack module comprises a top horizontal member which may be adjusted in length to accommodate decks with different widths. A vertical member is attached to the top horizontal member; one or more horizontal arms extend out from the vertical member. One or more of the horizontal arms may be adjustable in length. Material may be stored on an arm or arms of a single rack module or may be disposed across multiple such arms, including across multiple such arms of multiple rack modules.

This application claims priority to and is a continuation of application Ser. No. 11/956,754, filed Dec. 14, 2007 now abandoned which is incorporated herein in its entirety by this reference. 
    
    
     The invention relates generally to a rack which may be attached to a scaffolding system. 
     BACKGROUND 
     Many scaffolds comprise vertical risers and horizontal decks which may be raised and lowered on the vertical risers and/or which attach to fixed locations on one or more vertical risers. Workers often stand on a first deck while they use a second deck as a work surface as they shape and manipulate lumber, siding, pipe and tubing, wire, plastic sheeting, paint, and other material. Storing material on a deck may preclude using the deck for other purposes and may create an unsafe condition. As a storage area, a deck may be expensive, heavy, and over-engineered for the job. 
     The art has not demonstrated a structure or apparatus for a rack or shelf which may be semi-permanently attached to a deck, which is lighter in weight than a deck, and on which a variety of materials may be stored (semi-permanence as used in this disclosure means a structure or apparatus which is removable or which may be disengaged from a position or arrangement relative to another structure or apparatus without the use of tools). 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
     Generally stated, one or more rack modules may be semi-permanently attached to a deck to provide storage for material. Each rack module comprises a top horizontal member which may be adjusted in length to accommodate decks with different widths. A vertical member is attached to the top horizontal member; one or more horizontal arms extend out from the vertical member. One or more of the horizontal arms may be adjustable in length. Material may be stored on an arm or arms of a single rack module or may be disposed across multiple such arms, including across multiple such arms of multiple rack modules. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a scaffold system and three rack modules attached to a deck of a scaffold as well as a detail view of a portion of a rack module attaching to a portion of a deck. 
         FIG. 2  depicts an elevation view of an embodiment of a rack module. 
         FIG. 3  depicts a perspective view of an embodiment of a top horizontal member. 
         FIG. 4  depicts a perspective wireframe view of an embodiment of a top horizontal member. 
         FIG. 5  depicts a perspective wireframe view of an embodiment of attachment hardware on a top horizontal member. 
         FIG. 6  depicts a perspective view of an embodiment of attachment hardware on a top horizontal member. 
         FIG. 7  depicts a perspective view of an adjustable horizontal arm and the same perspective in a wireframe view. 
         FIG. 8  depicts embodiments of pin means. 
         FIG. 9  depicts an embodiment of pin means or an embodiment of a pawl. 
         FIG. 10  depicts a perspective view of an embodiment of a top horizontal member and attachment hardware. 
         FIG. 11  depicts a perspective wireframe view of detail of an embodiment of a top horizontal member. 
         FIG. 12  depicts an elevation view of an embodiment of a top horizontal member. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. If an element appears in more than one figure, and if the element is modified in a later figure relative to the earlier figure, then the element may be identified with the same element number, followed by a decimal representation of the later figure number. 
       FIG. 1  depicts three rack modules  100 , attached to the deck  160  of a scaffold system; the scaffold system is depicted in a simple form, comprising an upper and a lower deck  160  and two vertical risers  150 . The scaffold system presented in the figures throughout are used as an example only and should not be understood as a limitation. A person  170  is depicted upon a deck  160 .  FIG. 1  also depicts a detail of a portion of the deck  160  fitting within a portion of the rack module  100 , discussed further below. 
       FIG. 2  depicts an elevation view of an embodiment of a rack module  100 . The rack module is depicted as comprising a top horizontal member  130 , a vertical member  105 , three arm members of fixed length  110 , and an arm member with adjustable length  120 . The top horizontal member  130  further comprises a first clasp  133 , a first top portion  131 , an end cap  135  comprising a second clasp  134 , a middle top portion  132 , an optional pin means  138  (discussed further herein), and optional holes or equivalent structures  136  in the first top portion  131  and the middle top portion  132 . Attached to the end cap  135  is optional attachment hardware  140 . The first clasp  133  is depicted as being located a distance from the vertical member  105 , though in any embodiment the first clasp may be attached to the top of the vertical member  105 . Other embodiments of the top horizontal member  130  are discussed further herein. This disclosure refers to adjusting or changing the length or overall length of the top horizontal member  130 ; it should be understood herein that this refers to adjusting the distance between the first and second clasps  133  and  134 . The vertical member  105  may be lengthened, using means similar to those described herein with respect to the horizontal top member  130  and/or the adjustable arm  120 . 
     The clasps  133  and  134  are generally depicted in the figures as being composed of rectangular components; in alternative embodiments, one or another of the clasps  133  and  134  may be rods of a circular, rectangular, or other regular or irregular cross section with an absolute distance across the longest length of the cross-section (such as the diameter of a circle or the hypotenuse bisecting a rectangle into two triangular sections) being sized to fit in a location such as within an opening in the side of a deck  160 , such as the generally tubular horizontal braces which are found on many scaffold decks, or above the flange which is found on many decks (such a flange being depicted in the detail view in  FIG. 1 ). In another embodiment, the deck  160  and/or the flange on a deck may comprise a notch into which a suitably formed clasp may be fitted. 
     The figures also depict the various members and components of the rack  100  as generally being composed of components with rectangular cross sections; in alternative embodiments, these members and components may have circular, triangular, or other regular or irregular cross sections. 
     The arm member with adjustable length  120  in  FIG. 2  is depicted as comprising a first arm portion  122  and a second arm portion  124 . Optional holes  128  are depicted in the first arm portion  122  and the second arm portion  124 ; also labeled in  FIG. 2  is optional pin means  126  (discussed further herein). A foot  125  is also depicted. 
       FIG. 3  depicts a perspective view of an embodiment of a top horizontal member. In addition to the features described with respect to  FIG. 2 ,  FIG. 3  also shows a spring-loaded pin  139  variation of the optional pin means (discussed further below) and a closer partial view of a self-retaining pin  138 . The spring-loaded pin  139  is shown protruding from one hole  136  in the middle top portion  132 ; additional spring-loaded pins  139  may be located in the other holes  136  and may protrude through the holes  136  in the first top portion  131  (in which embodiment the self-retaining pin  138  may not be present).  FIG. 3  also shows the end of a rod  142  and that the attachment hardware  140  in this embodiment comprises a knob. 
       FIG. 4  depicts a perspective wireframe view of the embodiment of a top horizontal member  130  depicted in  FIG. 3 . In addition to the features described with respect to  FIG. 3 ,  FIG. 4  also shows that the first top portion  131  and the middle top portion  132  may overlap. In these figures, the middle top portion  132  is depicted as fitting within the interior cross-section of the first top portion  131 ; in an alternative embodiment (see, for example,  FIGS. 10 and 11 ), the first top portion  131  may fit within the interior cross-section of the middle top portion  132 .  FIG. 4  also shows that holes  136  in the first top portion  131  and the middle top portion  132  may lie on a common plane and that the holes  136  in the first top portion  131  and the middle top portion  132  may be aligned along common central axis when the middle and the first arm portions are overlapped.  FIG. 4  also shows the pin means  138  and  139  (discussed further herein) extending through the first top portion  131  and/or the middle top portion  132 . 
       FIG. 4  also shows end cap  135  overlapping the middle top portion  132  and that the rod  142  extends from at least the middle top portion  132  to the attachment hardware  140 . The end cap  135  may be a component separate from the middle top portion  132 , as depicted in  FIG. 4 , or may be a permanent part of the middle top portion  132 . 
       FIG. 5  depicts a perspective wireframe view of an embodiment of an end cap  135  and attachment hardware  140  on a top horizontal member. In addition to the features shown in other figures, this figure depicts the rod  142  connecting to the middle top portion  132  at location  146 . All or some of the rod  142  may be threaded. The portion between number  146  and number  148  (extending into the middle top portion  132 ) may further comprise a female threaded receptacle for receiving the rod, in which case the rod may be permanently (permanence indicating that it may be removable, but only through the use of tools) attached to the attachment hardware knob  140 . In another embodiment, the portion between  144  and  142  (extending into the attachment hardware  140 ) may further comprise a female threaded receptacle for receiving the rod, in which case the rod may be permanently attached to the middle top portion  132 . 
       FIG. 6  depicts a perspective view of an embodiment of an end cap  135  and attachment hardware  140  on a top horizontal member  130 . In addition to the features shown in other figures, this figure depicts a cam lever arm  180 . The cam lever arm  180  comprises an axis  182  which is either off-center in a circle or which is off-center of or at the center (between the foci) of a non-circular ellipse or another geometric form which provides a similar function. The ellipse is connected to a lever arm and may be rotated around the axis  182 . The cam lever arm  180  may further comprise a collar  184  for attachment and/or bonding to a rod, such as rod  142 . The collar may be threaded or not. Moving the lever arm rotates the ellipse and changes the distance between the axis  182  and the perimeter of the ellipse, which perimeter contacts a surface, such as the end cap  135  or the attachment hardware  140 , either tightening or loosing the resulting connection. 
       FIG. 6  depicts both a cam lever arm  180  and attachment hardware  140 . In an embodiment, the attachment hardware  140  may not be present, in which case the cam lever arm  180  may butt against the end cap  135  (see, for example,  FIG. 10 ). The cam lever arm  180  and the attachment hardware  140  may both be referred to generally as “attachment hardware.” 
     In the example shown in  FIG. 6 , with the lever arm  180  in a loosened position (approximately perpendicular to the position shown in  FIG. 6 ), the gross length of the top horizontal member  130  may be adjusted and the claps  133  and  134  located in the desired position along a deck  160 , as discussed herein. The lever arm  180  may then be moved to a tightened position (as shown in  FIG. 6 ), thereby tightening the end cap  135  against the middle top portion  132  and/or the first top portion  131  and securing the rack module  100  to the deck  160  through compression and friction. 
       FIG. 7  depicts a perspective view of an embodiment of an arm member with adjustable length  120  and a wireframe view of the same image. In addition to the features shown in other figures, this figure shows a closer view of an embodiment of the pin means  126  (this particular embodiment being similar to the self-retaining pin  138 ) and the wireframe view shows that the first arm portion  122  and a second arm portion  124  may overlap. 
       FIGS. 8 and 9  depict alternative embodiments of the pin means  126 / 138  and  139 . Pin means herein refers to a structure or apparatus comprising a rod, pawl, or similar structure which may be engaged with a notch, hole, or other opening in and/or through a first and/or a second structure, which engagement causes the first and/or second structures to be immobilized relative to one another and/or relative to a third structure. The rod, pawl, or similar structure may be attached to the first, second, or third structure or to no structure. The embodiments of pin means shown in this disclosure are for example only. 
     The embodiment of pin means numbered  126  or  138  is generally referred to herein as a self-retaining pin. Such self-retaining pins or similar apparatus may comprise a rod, an end cap, nut, flange or similar structure at one end of the rod, and a groove in the other end of the rod, in which groove a rectangular or similar structure may be located. The rectangular or similar structure may comprise a closed channel (not open to the perimeter of the rectangle) through which an axle may pass, the axle spanning the groove in the end of the rod. The rectangular or similar structure may be free to slide up and down, relative to the axle, as well as to rotate around the axle. The rectangular or similar structure may be manipulated to lie generally along a horizontal axis, relative to the central axis of the self-retaining pin, whereupon the pin may be passed through an opening or set of openings or channel, following which the rectangular or similar structure may be manipulated to lie generally perpendicular relative to the central axis of the self-retaining pin. When forces act on the self-retaining pin which might otherwise act to push the pin back through the opening, the rectangular or similar structure will block the passage of the pin. The rectangular or similar structure is analogous to a cotter pin passed through a hole in the end of a bolt. 
     Pin means  139  in  FIG. 8  depicts a spring-loaded pin. The spring-loaded pin comprises a central rod. Within or at both ends of the rod one or more springs may be found. The springs may exert force, generally outward along the central axis of the rod, upon end caps or end rods. There may be retainers, such as a flange, to prevent the end caps or end rods from being ejected by the springs. In operation, the end caps or end rods may be compressed against the springs, resulting in an overall shortening of the length of the spring-loaded pin  139 . When the spring-loaded pin and or other structures are at the desired location, the compressed end caps or end rods may be released, resulting in an overall lengthening of the spring-loaded pin  139 . The lengthened spring-loaded pin may engage with a first and/or second structure, as discussed above. 
       FIG. 9  depicts a third embodiment of pin means  190 . In this embodiment, a leaf spring  193  is attached at one end to the first top portion  131 . At the other end, a rod, tooth, or similar structure  192  is located in a position where it will engage with a hole, notch or similar  136 . A tab, ring, or similar structure or apparatus  191  may be provided which may allow a person or another structure or apparatus to bend the leaf spring  193  back to thereby remove the tooth  192  from its engaged position. The pin means  190  may be considered equivalent to a pawl which may also be part of a ratchet apparatus. In the example depicted in  FIG. 9 , the holes  136  in the first top portion  131  and the middle top portion  132  would be aligned along a common central axis, the pin means  190  would be released, and the rod or tooth  192  would pass through the aligned holes, preventing the first top portion  131  and the middle top portion  132  from moving relative to each other. 
       FIG. 10  depicts an alternative embodiment in which the first top portion  131 . 10  fits within the interior cross-section of the middle top portion  132 . 10  (the figure shows these portions in a non-overlapping configuration for the sake of clarity). This figure also depicts an alternative apparatus embodiment for adjusting the overall length of the top horizontal member  130 . In this alternative, a rod  200  passes through the length of the middle top portion  132 . 10  and into the first top portion  131 . 10 . The rod may be notched  204  along a section plane of its length. In this view, only the section plane and not individual notches are shown. The rod  200  may be rotated about its central axis, for example by rotating the cam lever arm  180 , to engage a pawl (which may be a spring-loaded pawl)  202  in the notches  204 . With the notches  204  engaged in the pawl  202 , the middle top portion  132 . 10  and rod  200  may be pushed toward the vertical member  105 , reducing the overall length of the top horizontal member  130 , with the pawl  202  engaging successive notches. The length may be shortened further and the clasps  133  and  134  tightened against the deck  160 , by rotating the cam lever arm  180  about its axle, as discussed above. The top horizontal member  130  may then be loosened by releasing the cam lever arm  180  and/or by rotating the rod  200  about its central axis to release the notches  204  from the pawl  202 , freeing the middle top portion  132 . 10  to be pulled away from the vertical member  105 . 
       FIG. 11  shows a wireframe view of the preceding figure, from a different vantage. In this figure, in addition to the features shown elsewhere, it is easier to see the section plane in which the notches  204  may occur. In this figure the gross features of a representative pawl  202  are shown on the interior of the first top portion  131 . 10  (a spring, in the case of a spring-loaded pawl  202 , is not shown). In this view, the pawl  202  is not engaged with the notches  204 . In this figure, a compression spring is represented by a tube as feature  206 , as well as a retainer wall (or equivalent structure)  208  for retaining the compression spring  206 ; a flange or similar on the end of the rod  200  to retain the spring  206  at that end is not shown. The figure illustrates one means through which a compression spring  206  may be incorporated into the top horizontal member  130 , serving to drive the first top portion  131 . 10  and the middle top portion  132 . 10  toward one another (which may assist a person in placement of a rack  100  in relation to a deck  160 ). It should be understood that many different arrangements of a spring, piston, or similar may be employed to provide a similar function. 
       FIG. 12  shows an alternative embodiment in which the clasps  130 . 12  and  134 . 12  define openings which face the opposite way from that shown elsewhere, to attach to a flange or similar structure which may be present on the interior walls of a deck  160 . It would be understood that, in such an embodiment, the top horizontal member  130  would be shortened to be released from the deck  160  and lengthened to be attached to the deck  160 . 
     There exist a number of different embodiments which would allow the length of the top horizontal member  130  or equivalent structure to be adjusted in a gross fashion to a length at which a attachment hardware  140 , cam lever arm  180  or equivalent may be used to make a final length adjustment and to secure the rack module  100  to a deck  160  through application of pressure and friction. 
     As presented in the figures, the gross length of the top horizontal member  130  may be adjusted by changing the amount of overlap between the first top portion  131  and the middle top portion  132 , such as through manipulation of the pin means  138  and/or  139  and by pushing or pulling the first top portion  131  and the middle top portion  132  together or apart to change the amount of overlap. Before or after adjusting the gross length of the top horizontal member  130 , the first clasp  133  may be positioned on the deck  160 , a first portion of the deck  160  being positioned within the opening defined by the first clasp  133 . If it is not already, the end cap  135  may be loosened and a second portion of the deck  160  (the second portion being on the opposite side from the first portion, the first and second deck portions being defined only by their positions relative to one another) may be positioned within the opening defined by the second clasp  134 . The end cap  135  may then be tightened onto the middle top portion  132  using the attachment hardware  140  or  180 , such as by rotating the attachment hardware knob  140 , which rotation may cause the rod to be threaded into the female threaded receptacle (which female threaded receptacle may be located in either the middle top portion  132  or the attachment hardware knob  140 ), or by moving the cam lever arm  180  into a tightened position. Reversing the rotation may loosen the end cap  135 . The attachment hardware  140  or  180  acts to fine-tune the overall length of the top horizontal member  130 , allowing the rack  100  to slide back and forth along a deck  160  when loose and, when tight, snugging the clasps  133  and  134  against the deck  160  and holding the rack  100  in place through pressure and friction. 
     The figures discussed above present example means to adjust the overall length of the top horizontal member and through which means a rack may be attached or secured to a deck  160  through pressure and friction. All alternative embodiments are not presented, there being many equivalent structures and apparatus which could provide the same function. Many of the means described above include a first means to adjust the gross length of the top horizontal member  130 , such as manipulate of the pin means and by changing the amount of overlap between the first and middle top portions, and a second means to fine-tune or make a final adjustment to the length of the top horizontal member  130  and to releaseably secure the finally adjusted length, thereby securing the rack  100  to a deck  160  through pressure and friction. The various means to adjust the overall length of the top horizontal member may be combined in other combinations to achieve the same function of securing the rack  100  to a deck  160  through pressure and friction. 
     The means of adjusting the overall length of the top horizontal member  130  to attach or secure a rack  100  to a deck  160  may comprise any apparatus which changes the overall length of the top horizontal member  130  and which may be manipulated between at least two settings, one tight, the other loose. The tight setting should offer resistance to being loosened, to avoid unintended disengagement of the rack  100  from a deck  160  while allowing a person to reset the apparatus into the loose setting, preferably without the use of tools. The attachment hardware  140  and cam lever arm  180  depicted herein are provided as examples, not as exclusive embodiments of such means. 
     Another example of such means may comprise two rods connected by a joint. The two rods may be connected at their far ends to two points. The two points may be restrained in their allowed motion by a frame, such as by a first and a second overlapping member (much as is shown in the figures), which allows the points to move toward or away from each other along a line. The distance between the points along the line may be changed by displacing the joint up or down, with the horizontal configuration (when the rods and the joint lie on a common horizontal plane) being the configuration with maximum distance between the points. If the two points are in contact with objects which are a distance apart which is slightly shorter than the maximum allowed distance between the points and if the rods or other components provide a degree of compressibility and if the joint is allowed to move further on a first side of the horizontal plane than on a second side (movement into the second side being restrained by a block, by other geometry of the apparatus, or by similar means), then a graph of the compression pressure between the points would roughly follow a curve, with peak pressure occurring at the horizontal configuration, the least pressure (potentially zero or even negative pressure) occurring when the joint is displaced onto the first side (which allows the furthest movement from the horizontal configuration) and an intermediate positive pressure level occurring when the joint is displaced into the second side. The geometry of such an apparatus typically precludes the device coming to a rest in the horizontal configuration, favoring resting states on the first side or the second side. 
     Such an apparatus would meet the criteria of providing a first loose setting (when the joint is displaced onto the first side) and a second tight setting (when the joint is displaced onto the second side). The energy required to move the apparatus from the tight to the loose setting would be related to the distance the joint is allowed to be displaced onto the second side relative to the horizontal configuration and the compressibility of the rods or other components. Such an apparatus may be used instead of the cam lever arm  180  or attachment hardware  140  discussed above. Such an apparatus may be combined with another apparatus which other apparatus may adjust the gross distance between the two points, while the apparatus performs a final adjustment of the distance between the two points and non-permanently locks the points into place, such as by displacement of the joint into the second side. Other alternative means may include apparatuses such as buckles, including jointed buckles and/or buckles with straps and/or buckles with a ratchet-like action, which may be used to draw a first and a second component together under pressure. 
     The rack  100  may be fabricated from a variety of materials, including, for example and without limitation, aluminum, iron, steel, stainless steel, nickel, copper, magnesium, titanium, bronze, alloys thereof, galvanized metal, fiberglass, carbon fiber, plastic, wood, and fiberboard, to name but a few examples.