BACKGROUND OF THE INVENTION

[0001] Agility ladders are used to improve speed and agility. Generally an agility ladder has lateral rungs attached to left and right side strips of webbing. The rungs are often plastic tubes, rods or strips. When unrolled or laid out on the ground, the agility ladder forms a column of open boxes or spaces. Depending on the specific training exercise the user's objective is to run, jump or hop through the ladder using a predetermined pattern of foot placement. Although these types of agility ladders have advantages, drawbacks with them remain. For example, the webbing can become tangled, causing delays in set up. The rungs in these types of agility ladders are also easily displaced by a user's foot, requiring frequent adjustment during use. Improved designs are needed.

SUMMARY OF THE INVENTION

[0002] In one aspect, an agility ladder has a plurality of rungs. A left link assembly has ends pivotally attached to left ends of first and second rungs, and a right link assembly has ends pivotally attached to right ends of the first and second rungs. The left and right link assemblies each include first and second links joined at a link pivot joint which keeps the links in an under center position, so that the links do not become precisely parallel when the ladder is deployed. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] In the drawings the same reference number indicates the same element in each of the views. [0004] Fig. 1 is a top perspective view of an agility ladder in the deployed position and ready for use.

[0005] Fig. 2 is a plan view of the agility ladder as shown in Fig. 1 .

[0006] Fig. 3 is a plan view of the agility ladder of Fig. 1 in an intermediate position between the deployed position shown in Fig. 1 and a folded or collapsed position.

[0007] Fig. 4 is a bottom view of the agility ladder as it is shown in Fig. 3.

[0008] Fig. 5 is a plan view of the agility ladder of Figs. 1 -4 now shown in the folded position.

[0009] Fig. 6 is a bottom view of the agility ladder as it is shown in Fig. 5.

[0010] Fig. 7 is an enlarged bottom perspective view of the agility ladder in the deployed position.

[0011] Fig. 8 is an enlarged bottom perspective view of a rung pivot joint.

[0012] Fig. 9 is a left side perspective view of the agility ladder section shown in Fig. 8.

[0013] Fig. 10 is a right side perspective view of the agility ladder section shown in Fig. 8.

[0014] Fig. 1 1 is a bottom perspective view of a link pivot joint.

[0015] Fig. 12 is a plan view of the link pivot joint shown in Fig. 1 1 . DETAILED DESCRIPTION OF THE DRAWINGS

[0016] As shown in Figs. 1 -4, an agility ladder 20 includes lateral rungs 22 pivotally connected via folding longitudinal link assemblies 28. Each link assembly 28 includes two links 24, with the inner ends 25 of the links joined to each other at a link pivot join 32, and with the outer end 27 of each link joined to a rung 22 via a rung pivot joint 30. The rungs 22, which may all be the same, typically are 30-100 cm long and 4 to 10 cm wide.

[0017] The rung 22 may have a flat bottom surface so that the rung lays flat on the ground. Referring to Fig. 7, substantially the entire length of the rung 22 may be continuous and flat, or the rung may have one or more solid flat bottom sections 40 and ribs 44 and recesses 46. These features may be molded into the rung during manufacture if the rung is made of a plastic material. The bottom surface of each rung may lay in a common plane.

[0018] Turning to Figs. 7-10, the outer ends 27 of adjacent links 24 are pivotally attached onto the bottom surface of the rung 22 at the left and right ends of the rung via a rung pivot joint 30. The rung pivot joint 30, in the example shown, may have a pivot post 60 on the rung projecting through holes in the outer ends of the links, with a post head 64 retaining the links onto the pivot post 60, optionally with a washer 62 between them. As shown in Fig. 8, where the bottom of the rung 22 has recesses 46, one or more ribs 44 may be provided between the recesses and parallel to the edges 48 of the rung 22. The edges 48 may be rounded or angled to better avoid interfering with the user's feet. Fig. 5 shows a design where the edges 48 are angled. The top surface of the rung may be flat or curved.

[0019] Referring still to Fig. 8, the left and right ends of the rung 22 may formed as a solid end block 56 to better support the pivot post 60. As shown in Figs. 7-10, the inner and outer ends of the links 24 may be rounded or chamfered. As illustrated in Figs. 8-10, a first fitting 34 may be provided on the right end of the rung, and a second complimentary fitting 36 provided on the left end of the rung 22. The fittings are complimentary in that they are designed to engage with or into each other. In the example shown, the fittings are a hook and a bar, respectively. Where two or more agility ladders 20 are used side-by-side to form two or more columns, the fittings allow adjacent ladders 20 to be attached to each other. Of course, various other types of fittings may equivalently be used, such as snaps, pins, interlocking tabs, etc.

[0020] Turning to Figs. 1 1 and 12, the link pivot joint 32 is designed so that the link assembly 28 can only fold inwardly as shown in Fig. 3, and not outwardly. The link pivot joint 32 is also designed to maintain the two links 24 of the link assembly 28 at an angle less than 180 degrees. Generally the angle between the links 24 is limited to about 165-175 degrees, and a maximum of 179 degrees. Consequently, with the agility ladder fully deployed, there is still a slight angle between the links, as shown in exaggerated form in Fig. 7 for purpose of illustration.

[0021] At each link pivot joint 32 both links can pivot freely, and at each rung pivot joint 30, each link and the rung can pivot freely. Consequently, pivoting movement of any link or rung does not transmit torque to any other link or rung. All links may have the same length, and may also be the same part. Generally the link length may be 40 or 45 to 48 or 49 % of the rung length. Longer links allows for increased range of spacing between rungs. The links and rungs may be a resilient flexible material, such as plastic, with a thickness of 2-5 mm.

[0022] In the example shown, the link pivot joint 32 may include a pivot pin 72 on a first or overlying link extending through a hole in the a second or underlying link, with a pin head 74 retaining the second link onto the pivot pin 72, and to form a pivoting connection between the first and second links. To limit the movement of the link pivot joint to 179 degrees or less, a curved lug 78 on the first link may project into an arcuate slot 76 in the second link, with the lug 78 bottoming out at the end of the slot 76 at the limit of travel.

[0023] In use, the agility ladder 20 may be stored or transported in the folded position shown in Figs. 5 and 6. In this position the rungs may be touching each other, or only minimally spaced apart. The length of the agility ladder 20 when folded is the sum of the combined width of each rung. In most designs, the agility ladder 20 has 4 to 10 rungs, with designs having 5, 6 or 7 rungs most often used. For an agility ladder having 6 rungs as in Figs. 1 -3, and a rung width of 5 cm, the length of the agility ladder 20 in the folded position is 30 cm. The thickness or height of the agility ladder may range from about 6 to 20 mm. The width of the agility ladder is the length of the rungs 22. As a result in the folded position the agility ladder is highly compact. As shown in Fig. 6, in the folded position the inner ends of the links 24 may be minimally spaced apart, e.g., by 1 -10 mm.

[0024] The agility ladder 20 may be deployed by pulling the end rungs 22 away from each other. Each of the link assemblies acts independently of the other link assemblies. Consequently, the ladder may optionally be deployed on a curve, with the rungs forming acute angles rather than being parallel. In this configuration the ladder may form non-parallelogram shaped spaces. For example, as shown in dotted lines in Fig. 7, a triangle may be formed between adjacent rungs. In addition, any adjacent rungs may be left together with no space formed between them, with non-adjacent rungs forming squares or other shapes. Stakes may optionally be used to secure the ladder onto the ground.

[0025] The ladder may optionally be used in a non-fully deployed position as shown in Fig. 3, to provide smaller foot target spaces. The ladder may be refolded by pushing the end rungs towards each other. The link pivot joint 32 insures that the link assemblies 28 remain in an under center configuration so that they fold inwardly when the ladder is folded or collapsed.

[0026] Complementary means that the first fitting is designed to engage with the second fitting, to allow two ladders side-by-side to be attached to each other. Substantially parallel means parallel to within 5 degrees or less. Substantially touching each other means actually touching or spaced apart by less than 5 mm.

[0027] The rungs attached to each other substantially only by the link assemblies means that there is no other element of consequence in the operation of the ladder attaching them. Inconsequential elements such as a rope, ribbon, or tape that cannot act in both tension and compression, are not excluded.