You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 11/385,715, filed on Mar. 22, 2006, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to systems for storing lengths of pipe in industries such as oil and gas drilling. 
     Oil and gas drilling operations require the availability of a number of lengths of pipe that are added sequentially to pipe strings in order to drill a well. Heretofore, many arrangements have been used for temporary storage of the pipes prior to use. The known arrangements present a number of drawbacks. Among these are that they do not create safe conditions for operating personnel, are difficult to use, particularly when several layers of pipe are to be stored, and allow removal of individual lengths of pipe only with difficulty. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a novel system that allows such pipes to be stored, even in several layers, and allows individual pipes to be removed, as needed, safely and easily. 
     According to the invention, pipe racks and strips for supporting additional layers of pipe are provided with novel and safe pipe stop devices that can easily be moved from a stop position to a retracted, or withdrawn, position, allowing removal of individual pipes. According to certain embodiments of the invention, movement from the stop position to the retracted position occurs in the direction away from a pipe in contact with the device, thereby facilitating operation of the device. According to other embodiments of the invention, the pipe stop is removed in order to permit removal of a length of pipe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective view of one end portion of a pipe rack according to the invention. 
         FIG. 2  is a detail, elevational cross-sectional view of a portion of one component of the pipe rack of  FIG. 1 . 
         FIG. 3  is a top plan view of the portion shown in  FIG. 2 . 
         FIG. 4  is an elevational view of a pipe supporting strip according to the invention. 
         FIG. 5  is a perspective view of a pipe storage system according to the invention employing racks and strips as shown in  FIGS. 1-4 . 
         FIG. 6  is a perspective view of one component of another embodiment of a pipe supporting strip according to the invention. 
         FIG. 7  is a pictorial view of a second component of the other embodiment of the pipe supporting strip. 
         FIG. 8  is a perspective view of a third component of the other embodiment of the pipe supporting strip 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 ,  2  and  3  show one end of a pipe rack provided with pipe stop elements according to one embodiment of the invention. The rack is composed of first and second tubular base elements  10  and  12  and an elongated pipe supporting element  14 . At least element  14  is hollow, while base elements  10  and  12  may or may not be hollow. Element  14  is secured to elements  10  and  12  by supporting plates, or tubes, etc.,  18 , each welded to element  14  and to a respective one of elements  10  and  12  to provide a rigid structure. Connecting elements may also be welded between base elements  10  and  12  for added rigidity. Other forms of connection among elements  10 ,  12  and  14  can obviously be employed. For example, these could include triangular plates each vertex of which is connected to a respective tubular element. 
     While elements  10 ,  12  and  14  have been illustrated to have a circular cross-section, it will be appreciated that they can have other cross-sections, such as square or rectangular. Alternatively, these elements can be in the form of I-beams provided with safety stop assemblies along their sides. 
     Pipe supporting element  14  is provided with a plurality of safety stop assemblies  20  spaced apart along the length of element  14 , preferably at regular intervals. For example, assemblies  20  may be spaced apart at intervals of 5 to 8 feet. 
     Referring to  FIGS. 2 and 3  together with  FIG. 1 , each safety stop assembly  20  is composed of a pipe stop member  22 , which may be in the form of a steel plate having a thickness of, for example, one-half inch. Plate  22  has two through openings  24  and  26 . A pin  30  extends through aligned openings in tubular element  14  and opening  24  in member  22 . Pin  30  may be threaded at its end to be secured to a nut  32  in order to hold pin  30  in place. Assembly  20  includes a further pin  34  that extends through other aligned openings in tubular element  14 . Pin  34  is provided at one end with an enlarged head having a larger diameter than the openings in element  14  and at the other end with a small diameter through hole (not shown) for receiving a retaining pin  38  that may be in the form of a cotter pin. Pin  38  may be permanently secured to element  14  by a wire, or length of wire cable, to prevent it from being lost (as employed in the embodiment of  FIGS. 6-8 ). 
     In  FIGS. 2 and 3 , stop member  22  is shown in its stop position, this being illustrated in solid lines in  FIG. 2 . Member  22  is held in this position by pin  34 , bearing against one longitudinal edge of member  22 . In this position, member  22  will prevent a pipe (not shown) that rests on the upper surface of element  14  and bears against stop surface  40  of element  22 , from rolling off of the pipe rack. 
     When a pipe is to be removed from the rack, pin  38  is withdrawn from the hole in the end of pin  34  and pin  34  is then withdrawn in order to allow stop member  22  to pivot downwardly, away from the pipe, into the retracted position shown at  22 ′ in  FIG. 2 . The pipe may then be guided off of the rack and removed for use. When member  22  is in the retracted position  22 ′, pin  34  may be reinstalled, passing through opening  26 , in order to hold member  22  in the retracted position and prevent pin  34  from being lost. 
     Preferably, one pipe stop assembly  20  can be installed at a distance of 6 inches from one end of tubular element  14  and the pipe rack can have a length of 20 to 30 feet and an overall height of only 18 to 48 inches. 
     The upper end of each member  22 , i.e. the end that is remote from opening  24 , is provided with a recess, or notch,  42  that constitutes a finger grip to aid displacement of member  22  from its retracted position to its stop position. Such displacement requires withdrawal of pin  34  and reinstallation of that pin after member  22  has been brought to its stop position. 
     Each assembly  20  is associated with a longitudinal slot  44  in the upper surface of element  14  to allow stop member  22  to pivot from its stop position to its retracted position. 
     A second component of the invention is shown in  FIG. 4 . This component is in the form of a metal interlocking safety track, or strip, carrying one or more safety stop assemblies, is shown in  FIG. 4 , which is a side elevational detail view. This strip includes at least one elongated pipe supporting element in the form of a housing  50 , preferably but not necessarily of rectangular cross-section, containing a safety stop assembly  20  having the same structure as shown in  FIGS. 2 and 3 . Housing  50  is provided on its upper surface with a slot corresponding to slot  44 .  FIG. 4  also shows a pipe  60  being held in position by stop assembly  20 . 
     Housing  50  may have a length of the order of 5 to 8 feet and may be joined to a further housing  70  that also carries a safety stop assembly  20 . Housing  50  and  70  could be identical to one another. In order to join housings  50  and  70  together, housing  70  is provided with two fastening plates  74  that are welded to housing  70  and that have free ends insertable into the end of housing  50 . Housing  50  is provided, in its two opposed vertical sides, with through openings  76  that will align with through openings in plates  74  to allow insertion of a pin that will hold housings  50  and  70  together in their assembled condition. Further identical housings can be connected in order to provide a strip having any desired length. 
     It will be appreciated that, within the framework of this invention, the housings could be fastened together in a wide variety of ways. 
     An important feature of embodiments of the invention resides in the fact that movement of pipe stop member  22  between its stop position and its retracted position is in a direction away from the pipes being held in place by stop member  22 . This assures that movement of stop member  22  to its retracted position is not opposed by the force of a pipe, such as  60 , against stop surface  40 . 
       FIG. 5  shows a pipe storage system incorporating features of the present invention. A plurality of racks each having the form shown in  FIGS. 1-3  are placed on the ground and a first row of pipes  60  is laid on the racks. Then, a plurality of safety strips each having the form shown in  FIG. 4  are then placed on the first layer of pipes, and a second layer of pipes  60  can then be placed on those strips. The stacking of pipes can continue with the addition of further strips and further layers of pipe. When it is desired to roll a pipe off the topmost layer off of the stack, appropriate ones of stop members  22  are moved to their retracted positions, and the pipe can easily be rolled off of the underlying strips or racks, after which members  22  can be returned to their stop positions. 
     According to a further feature of the invention, the safety strips can be reinforced by inserting pieces of lumber or other rigid materials therein. 
       FIGS. 6-8  illustrate several components of another embodiment of a metal interlocking safety track, or strip, according to the invention, including one or more safety stop assemblies. As shown in  FIG. 6 , this embodiment includes one or more housings, which are hollow and may have a square or rectangular cross-section. Each housing has two opposed side walls  82  and each sidewall is provided with a series of through holes  84 . The through holes  84  in one side wall  82  are aligned, along the longitudinal axis of housing  80 , with the through holes  84  in the other side wall  82 . 
     When several housings  80  are to be joined together to form an elongated strip, they will placed end-to-end and connected together by a suitable connecting piece such as connecting piece  88 . 
     Connecting piece  88 , in the illustrated embodiment, has a generally H-shaped form and is composed of two longitudinally extending side walls joined together by a crosspiece. Each side wall is provided with two through holes  90 , the through holes in one side wall being aligned, along the longitudinal direction of the strip, with corresponding through holes in the other side wall. 
     To assemble two housings  80  together, one end of each housing is introduced into connecting piece  88  so that the housing end abuts against one side of the crosspiece, as shown for one housing  80  in  FIG. 6 . When thus arranged, one through hole  90  in each wall of piece  88  is aligned with a corresponding through hole  84  in housing  80 . 
     In order to retain the connection between connecting piece  88  and each housing  80 , a pin  92 , as shown in  FIG. 7 , will be inserted through the mating through holes  84  and  90  along each side of housing  80 . Pin  92  may be provided with two through holes  94  and a cable, cord, or rope,  97  can be initially fastened in one of through holes  94  and can then be secured in place by any suitable means in the other through hole  94  after pin  92  has been inserted into the corresponding through holes  84  and  90 . 
     The safety strip according to this embodiment is completed by a safety stop assembly composed of a pipe stop member  96  and another pin  92 , as shown in  FIG. 8 . Pipe stop member  96  includes a U-shaped attachment part having vertical side walls  98  and a horizontal top wall  100  that joins side walls  98  together. Pipe stop member  96  further includes a pipe stop part  102  that extends upwardly from top wall  100 . Parts  98  and  102  are rigidly connected together and may be formed as a one-piece unit. 
     Each side wall  98  is provided with a through hole  106 , the two through holes  106  being aligned with one another along the longitudinal direction of the strip. Stop part  102  is also provided with a through hole  108 . 
     Stop member  96  is placed upon housing  80  at a desired location, with member  96  being oriented so that a pipe to be retained will bear against an inclined stop surface  110  of stop part  102 . The stop surface of the stop part forms an obtuse angle with the pipe supporting surface. 
     Member  96  will be held in place by aligning through holes  106  with a selected pair of through holes  84  and then inserting a pin  92  through holes  84  and  106 . Cable  97  may then be threaded through hole  108  and then secured in any suitable manner to the through hole  94  at the leading edge of pin  92 . 
     Pipe stop member  96  could also be dimensioned to be capable of being placed upon connecting part  88 , in which case, pin  92  would be inserted through the associated pairs of holes  106 ,  90  and  84 , to hold pipe stop member  96  in place. 
     Preferably, elements  14 ,  50 ,  70  and  80  are positioned so that their pipe supporting surfaces are horizontal. This assures that when safety strip assemblies are retracted or removed to withdraw one pipe, the remaining pipes will not roll off and the stop assemblies can be returned to their stop positions. 
     This application relates to subject matter disclosed in U. S. Provisional Application No. 60/664,293, filed on Mar. 23, 2005, the disclosure of which is incorporated herein by reference. 
     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
     The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Summary:
A device for supporting a group of pipes during temporary storage, the device being composed of: an elongated pipe supporting element having a pipe supporting surface; and at least one safety stop assembly including a pipe stop member and at least one fastening element, wherein the pipe stop member is movable relative to the pipe supporting element between a stop position and a withdrawn position, the stop member, when in the stop position, resting on the pipe supporting element and being operative to prevent removal of pipes from the pipe supporting element, and the stop member being operative, when in the withdrawn position, to allow removal of pipes from the pipe supporting element, and the at least one fastening element being connectable between the pipe supporting element and the pipe stop member for holding the pipe stop member in the stop position.