Patent Publication Number: US-6334261-B1

Title: Collapsible square

Description:
FIELD OF THE INVENTION 
     The present invention relates to a collapsible square that can be folded into a storage position and unfolded to a deployed position capable of measuring predetermined angles. 
     BACKGROUND OF THE INVENTION 
     Squares are frequently used in the construction industry to layout and mark building materials. Squares are used, for example, during framing, tiling, cabinet installation and masonry work. Squares have two or more legs that form an angle such as a 90 degree angle. One leg is placed against a first structure, such as a foundation or floor, and the second leg is used to position or mark a second object, such as a sheetrock panel or a board used to construct a building frame, relative to the first structure. It is desirable that the legs of the square be long enough to span a substantial length along each structure to facilitate the positioning or marking. Therefore, the legs of the square are typically several feet long. 
     Because the legs of the square are long and are perpendicular in use, squares in their deployed positions are large and cumbersome to transport and store. Consequently, many squares are constructed so that the legs are movable relative to one another so that the square can fold or “collapse” into a storage position when not in use. Although the ability to move the legs of the square between deployed and folded positions facilitates transport and storage of the square, the manner of connection between the leg portions sometimes interferes with straight overlapping alignment of the leg members in the storage position or requires disconnection of one or more joints to move the legs into their storage position. Other squares provide for a movably adjustable connection between the leg members. However, the movable connection between the leg members may introduce the requirement of tedious angular adjustment to a desired angle and the possibility of slight angular misalignment when the square is moved into its deployed position. 
     Many squares include two elongated legs that form an angle and an elongated member or brace that holds the elongated legs in angle forming relation. U.S. Pat. No. 4,955,141, for example, shows an adjustable square that includes two legs that are pivotally mounted together and an elongated blade member that functions to releasably hold the two legs in a selected angular position. The elongated blade member is pivotally connected to one leg and slidably engaged within a longitudinally extending slot in the other leg. This type of device does not automatically move into a right angle position when fully deployed. In addition, they do not form a true right triangle, as the leg members extend beyond the intersection with the hypotenuse. 
     Many squares have three legs that are mounted together for movement between folded and deployed positions (and/or for angular adjustment) by sliding connections or by a combination of sliding and pivoting connections. U.S. Pat. No. 1,640,604, for example, shows a combination square having three legs, two of which are pivotally connected together and the third of which is slidably engaged with the first and second legs for angular adjustment. Patent reference WO 98/47,720 shows a square in the form of a 3-4-5 right triangle having two legs pivotally mounted to the largest leg (the hypotenuse) and slidably engaged with each other for movement between storage and deployed positions. One disadvantage of WO 98/47,720 is that the compactness of the square when in the storage position is limited by the length of the hypotenuse leg. Another disadvantage of many prior art squares is that they do not enable the square to be automatically and effectively locked in a right angle, deployed configuration. 
     In addition, sliding linkages between adjacent legs are generally disadvantageous because they are a possible source of inaccuracy when the square is set in a position of angular adjustment or when the square is moved to its deployed position. Thus, although sliding connections allow angular adjustment, these connections introduce the possibility of error and increase setup time. For squares that are movable between a folded position and a single deployed position, however, sliding connections are particularly undesirable because they introduce the possibility of error while providing no compensating advantage of allowing adjustability in the deployed position. Pivotal connections are more advantageous when a square assumes only two positions, a folded storage position and a deployed in position. Consequently, there is a need for square that is movable between storage and deployed positions using only pivotal connections between adjacent legs for movement between storage and deployed positions. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to meet the need identified above. To meet this need, a collapsible square constructed according to the principles of the present invention includes a first elongated rigid leg having first and second ends and a second elongated rigid leg having first and second ends. The second elongated rigid leg is pivotally connected at its first end to the first end of the first elongated rigid leg. The collapsible square further includes a hypotenuse member comprising two elongated rigid leg portions. A first of the leg portions of the hypotenuse member and a second of the leg portions of the hypotenuse member have their first ends pivotally connected to the second end of the first elongated rigid leg and the second end of the second elongated rigid leg, respectively. The first of the leg portions and the second of the leg portions have second ends thereof connected to one another in a manner which permits the hypotenuse member to be folded. The first leg, the second leg, and the hypotenuse member are connected to one another so as to be movable between 1) a storage position wherein the first leg, the second leg, and the hypotenuse member are disposed in linear overlapping relation with one another, and 2) a deployed position wherein the first leg, the second leg, and the hypotenuse member form a right triangle. A releasable lock structure disposed at the second ends of the first and second leg portions is constructed and arranged to releasably lock the first leg, the second leg and the hypotenuse member in the deployed position. 
     Another object of the present invention is to provide a collapsible square that automatically sets the right angle once the square is moved into the right angle configuration, without the need for manual adjustment or manipulation. Accordingly, the present invention provides a collapsible square that comprises a first elongated rigid leg having first and second ends, a second elongated rigid leg having first and second ends, the second elongated rigid leg being connected at said first end thereof to said first end of said first elongated rigid leg, and a hypotenuse member connected to the second end of the first elongated rigid leg and the second end of the second elongated rigid leg, respectively. The rigid legs and the hypotenuse member are connected to one another in a manner that permits the square to be movable between 1) a storage position wherein the first leg, the second leg, and the hypotenuse member are disposed in linear overlapping relation with one another, and 2) a deployed position wherein the first leg, the second leg, and the hypotenuse member form a right triangle. A releasable lock structure at the second ends of the first and second leg portions automatically locks the elongated rigid legs and the hypotenuse member in the deployed position when the leg portions and the hypotenuse member are moved into the deployed position. 
     Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an side elevational view of a collapsible square constructed according to the principles of the present invention showing the square in a deployed position; 
     FIG. 2 is a front elevational view of the collapsible square taken along the line of sight  2 — 2  in FIG. 4; 
     FIG. 3 is an enlarged sectional view of the square taken as indicated in FIG. 2; 
     FIG. 4 is a side elevational view of the square in a folded position; and 
     FIGS. 5 and 6 show the square in positions between the deployed and folded positions. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE OF THE INVENTION 
     FIG. 1 shows a collapsible square, generally designated  10 , constructed according to the principles of the present invention. The collapsible square  10  includes a first elongated rigid leg  12  having first and second ends  14 ,  16 , respectively and a second elongated rigid leg  18  having first and second ends  20 ,  22 , respectively. The second elongated rigid leg  18  is pivotally connected at the first end  20  thereof to the first end  14  of the first elongated rigid leg  12 . A third leg  24  includes first and second elongated rigid leg portions  26 ,  28 , respectively. The first of the leg portions  26  and the second of the leg portions  28  have respective first ends thereof,  30  and  32 , pivotally connected to the second end  16  of the first elongated rigid leg  12  and the second end  22  of the second elongated rigid leg  18 , respectively. 
     The first of the leg portions  26  and the second of the leg portions  28  have respective second ends thereof,  34  and  36 , connected to one another at a connection  38  in a manner which permits limited relative movement between the second ends  34 ,  36  thereof so that the third leg  24  can be folded at the connection  38  between the first and second leg portions  26 ,  28  to enable the first leg  12 , the second leg  18 , and the third leg  24  to be moved between 1) a storage position (see, for example, FIG. 4) wherein the first leg  12 , the second leg  18 , and the third leg  24  are disposed in linear overlapping relation with one another, and 2) a deployed position (see FIG. 1) wherein the first leg  12 , the second leg  18 , and the third leg  24  form a right triangle. As can be appreciated from FIG. 1, when the collapsible square  10  is in its deployed position, the third leg  24  forms a hypotenuse member of the right triangle. 
     A releasable lock structure  40  at the second ends  34 ,  36  of the first and second leg portions  26 ,  28  is constructed and arranged so that when the third leg  24  is moved from the storage position to the deployed position, the releasable lock structure  40  terminates relative angular movement between the leg portions  26 ,  28  when the first and second leg portions  26 ,  28  are in a substantially aligned linear relation with one another. 
     The structural details of the collapsible square  10  can best be appreciated from an examination of FIGS. 1,  2 ,  5  and  6 . Preferably the square  10  forms an isosceles right triangle in its deployed position. The first and second legs  12 ,  18  are preferably each approximately four feet long, 2 inches wide and 0.125 inch thick. The leg portions  26 ,  28  are each approximately two inches wide, 0.125 inch thick and are approximately 34.75 inches and 36.5 inches, respectively, in length. The total length of the third leg  24 , accounting for the partial overlap of the portions  26 ,  28  when the square  10  is deployed is approximately 67.9 inches. Preferably the first and second legs  12 ,  18  and the first and second leg portions  26 ,  28  are made from  6063  aluminum and are pivotally connected by rivets  42 ,  44 ,  46 , and  48 . It can be understood from FIGS. 2 and 5 that rivets  42 ,  44  and  46  are identical to each other and that rivet  48  is an elongated spacer rivet. 
     Operation 
     When the collapsible square  10  is disposed in its storage position (FIGS.  2  and  4 ), the legs  12 ,  18 ,  24  are in generally abutting, overlapping linear relation (i.e., they are co-linear). In its storage position, the square  10  is approximately four feet long, two inches wide and ½ inch deep (where depth is measured between opposing exterior surfaces  50 ,  52  of the square as best understood from FIGS. 2 and 3) so that the folded square  10  can be easily carried or stored. The heads of the rivets  42 ,  44 ,  46 ,  48  are essentially flush with the respective adjacent surrounding surface of the associated legs  12 ,  18 ,  24 . Each leg  12  and  18  and each leg portion  26 ,  28  is provided with an aperture  56 . When the square  10  is in its storage position, the apertures  56  on the legs  12 ,  18  and on the leg portions  26 ,  28  are axially aligned so that the square  10  can hang on a nail or hook when not in use. 
     To deploy the square  10 , the user pivots the first and second legs  12 ,  18  with respect to one another in an opening direction about the rivet  48 . A comparison of FIGS. 4-6 illustrates this opening movement. This pivotal movement of the legs  12  and  18  in turn causes opening pivotal movement of the leg portions  26 ,  28  of the third leg  24  about the associated rivets  42 ,  44 ,  46 . The square  10  includes movement limiting structure in the form of a first elongated pin member  58  rigidly mounted through the end  32  of the leg portion  28  of the third leg  24  and a second elongated pin member  60  rigidly mounted toward the end  30  of the first leg portion  26  of the third leg  24 . The first elongated pin member  58  extends generally through the leg portion  28  and is received within a notch  62  in the second leg  18  and a recessed edge portion  64  of the first leg portion  26  when the square is in its storage position. The second elongated pin member  60  extends generally from one side of the first leg portion  26  and is received within a notch  70  formed in the second leg portion  28  of third leg  24  when the square  10  is in its folded position. The members  58 ,  60  limit the movement of the legs  12 ,  18  and  24  when the same are moving in a folding (i.e., closing) direction and also restrict the unfolding movement of the legs  12 ,  18 ,  24  to movement in one opening direction. It can therefore be understood that the movement limiting structure (provided by members  58 ,  60  and associated structures) allows the square to be unfolded from the storage position in only one direction. 
     It can be understood from FIG.  2  and from a comparison of FIGS. 4 and 5, for example, that when the square  10  is in its folded position, the third leg  24  is disposed between the first and second legs  12  and  18 . Relative movement between the first and second legs  12 ,  18  in the unfolding direction commences the unfolding movement of the third leg  24 . When the first and second legs  12 ,  18  are pivoted partially toward their deployed positions (as in FIG. 6, for example), the user can pull outwardly on the center portion of the third leg  24  to straighten the same. This will move the three legs  12 ,  18 ,  24  into their deployed position and lock in the square  10  in its right triangular configuration (FIG.  1 ). The releasable lock structure stops the movement of the legs  12 ,  18 ,  24  in their opening directions when the deployed position is reached and locks the legs  12 ,  18 ,  24  in the deployed position. 
     Specifically, the releasable lock structure  40  includes a releasable locking assembly  70  (see FIG. 3) that stops and releasably locks the leg portions  26 ,  28  of the third leg  24  in a generally linear extended configuration, thereby releasably locking the square  10  in its triangular configuration. The structure and operation of the locking assembly  70  can best be understood from FIGS. 1,  3 ,  5  and  6 . The locking assembly  70  includes a spring blade  74  and a projecting member  76  that is rigidly mounted at one end of the spring blade  74 . The projecting member  76  has a cylindrical body portion  77  and is preferably a metallic structure that is secured within an aperture  81  in the spring blade  74  by swedged end  79 . 
     The spring blade  74  is generally disposed within a recess  78  formed within the leg portion  28  of the third leg  24  so that it is normally essentially flush with the side surface of the leg portion  28 . The spring blade  74  is rigidly secured to the second leg portion  28  by the rivet  46 . As the third leg  24  is moved into its deployed position (i.e., its linear extended position), the projecting member  76  slides over a beveled edge area  80  of the first leg portion  26  of the third leg  24  which causes the spring blade  74  to move resiliently outwardly of the recess  78 . When the leg portions  26 ,  28  of the third leg  24  are linearly aligned, the projecting member  76  is axially aligned with a recess in the form of an aperture  84  provided in the first leg portion  26 . The spring force of the spring blade biases the projecting member  76  in a leg locking direction into leg locking engagement with the aperture  84  to releasably lock the leg portions  26 ,  28  in linear relation and thereby releasably lock the square in its deployed configuration. Otherwise stated, the projecting members  76  automatically snaps into locking engagement in aperture  84  when the square is moved to the deployed position. The ends  16 ,  22  of the legs  12 ,  18 , respectively, and the ends  30 ,  32  of the leg portions  26 ,  28 , respectively, are mitered at forty five degree angles to form the triangular configuration in the deployed configuration. 
     Although preferred, the present invention contemplates that the releasable lock structure need not be of the type that automatically locks the square in the deployed position. Rather, a manually movable locking structure (e.g., such as tightening of a wing nut, moving a pivoted latch member or other locking mechanisms known in the art) can be used. 
     Because the square  10  forms an isosceles triangle in the deployed position, the square  10  can be used to measure 90 degree angles (using legs  12  and  18 ) and 45 degree angles (using leg  24  and either leg  12  or  18 ) during layout and construction. When the user has finished using the square  10 , the square can be easily refolded to its storage position by manually pushing the projecting member  76  out of locked engagement with the aperture  84 , pushing inwardly on the center of the third leg  24  to move the leg portions  26 ,  28  in a folding direction, and then moving in the first and second legs  12 ,  18  toward one another in a folding direction. It can be appreciated that the elongated pin members  58 ,  60  limit movement of the legs  12 ,  18 ,  24  in the folding direction as described above so that the legs  12 ,  18 ,  24  cannot be moved beyond their linear folded storage position when folding the square. 
     It can be understood that the square  10  shown in the figures and described herein is exemplary only and not intended to limit the scope of the invention. It is within the scope of the invention, for example, for the square to be an isosceles triangle having dimensions that are larger or smaller than those recited above. Similarly, although it is preferable for the square to form an isosceles triangle in the deployed position so that both 90 and 45 degree angles can be measured using the square in its deployed position, it is within the scope of the invention to provide a collapsible square that forms a right triangle in its deployed position but that is not an isosceles right triangle. 
     It should be appreciated that the automatic locking feature of the present invention is itself considered to be novel, and can be used irrespective of whether the legs and hypotenuse members are pivotally connected, slidably, or otherwise connected. For example, it is contemplated that the lock can be provided on an arrangement such as that disclosed by WO 98/47720, hereby incorporated by reference, so that when the sliding connection reaches a fully deployed right angle configuration, one of the corners is locked into a fixed angle. The lock is advantageous in that it sets the right angle once the square is moved into the right angle configuration, without the need for manual adjustment or manipulation. 
     It can thus be seen that the objectives of the present invention have been fully and effectively accomplished. It should be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the structural and functional principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications, alterations, and substitutions encompassed within the spirit and scope of the appended claims.