FIELD OF THE INVENTION
The field of the invention relates generally to security devices and safety devices, more specifically to devices to prevent climbing a ladder, and still more specifically to portable and removable ladder security devices.
BACKGROUND OF THE INVENTION
Ladders are often left unattended at worksites, towers, such as water storage towers, hunting stands and other locations as it is often more convenient to leave them in place rather than remove them after each use, possibly transport them off site and then put them in place again for the next use. Moreover, as in the case of towers and other permanent structures, ladders are often fixed in place and are not transportable. Whether fixed in place by convenience or necessity, ladders can provide a temptation to unauthorized persons to climb them to gain illegal or unsanctioned access to a building, hunting stand, or other structure.
U.S. Pat. No. 9,410,373 to Randolph discloses a plurality of sections of compressible material that are wrapped around the stringers of a ladder to cover the ladder rungs. Although the rungs of a ladder are covered, there are slits or openings between the sections which may allow someone to climb up the ladder placing their feet either onto the rungs themselves or resting their weight on the sections themselves. U.S. Patent Application Publication No. 2010/0236865 to Crowton, et al. discloses a blocking device attached to and extending horizontally from the ladder thereby blocking access to the upper portion of the ladder. The blocking device includes a pivotable plate that pivots away from the ladder to allow access. However, because the blocking device disclosed in the Randolph publication pivots into the user on the blocked ladder, it creates a safety hazard as it forces the user to pivot the blocking plate from below the plate so that the user is hanging onto the ladder with only one hand.
The prior art is replete with examples of ladder blocking devices in which the primary component is a covering such as a sheet, shell, and/or other covering device attached to the ladder thereby preventing a user from climbing by removing access to the rungs. However, there are several disadvantages in such devices in that they are often clumsy to carry and they block only the lower rungs of the ladder. In addition, the attachments of the rung covers to the ladder are almost by necessity easily reached by an unauthorized user making them relatively easy to remove, overcome or bypass.
Therefore, it can be seen that there is a need in the art for a ladder blocking device that is difficult to bypass and easily carried to the location of the ladder.
SUMMARY OF THE INVENTION
The present invention broadly comprises a ladder blocking device including a first support wherein the at least one first support ranges at least from a first stringer of the ladder to at least a second stringer of the ladder; a first plurality of prongs, each one of the plurality of prongs extending from the first support; and an attachment means to attach the first support to the ladder. In a preferred embodiment, the present invention further includes a second support wherein the second support includes a second plurality of prongs having an attachment means to attach directly or indirectly to the ladder and wherein the second support is connected to the first support. In an alternate embodiment, one or both of the first and second plurality of prongs supports a shield.
The present invention also broadly comprises a first support wherein said at least one first support ranges at least from a first stringer of said ladder to at least a second stringer of said ladder; a first shield fixedly attached to said first support; and, an attachment means to attach said first support to said ladder. In a preferred embodiment, the invention further includes a second shield fixedly attached to a second support; wherein the first support is connected to the second support to form a shield unit.
The present invention also broadly comprises a ladder assembly that includes: a ladder including a pair of stringers and a plurality of rungs extending between and fixedly attached to each one of the pair of stringers, the pair of stringers arranged in a parallel manner; and, a ladder blocking device including: a ladder including a pair of stringers and a plurality of rungs extending between and fixedly attached to each one of said pair of stringers, said pair of stringers arranged in a parallel manner; and, a ladder blocking device that includes a support assembly wherein a first blocking support and a second blocking support each range at least from a first stringer of said ladder to at least a second stringer of said ladder; and, an attachment means to attach said support assembly to said ladder. The ladder blocking device may include a locking means. In an alternate embodiment, the ladder assembly may further include a first shield fixedly attached to the first blocking support and a second shield fixedly attached to the second blocking support. In a different embodiment, the ladder assembly may further include a first plurality of prongs attached to the first blocking support and a second plurality of prongs attached to the second blocking support. Each of the first plurality of prongs may support a first shield and the second plurality of prongs may support a second shield.
An object of the invention is to provide a portable apparatus to block use of a ladder.
A second object of the invention is to prevent accidents caused by unsafe use of a ladder.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The nature and mode of the operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing Figures, in which:
FIG. 1 is a top view of one embodiment of the ladder blocking device of the present invention;
FIG. 2 is a top view depicting the blocking device attached to and supported by a ladder;
FIG. 3 is a front view of the blocking device attached to the ladder;
FIG. 4 is a partial side perspective view of the combined ladder and blocking device assembly showing a locking mechanism holding the supports together;
FIG. 5 is an enlarged partial top view of the invention in which each support of the blocking device includes additional prongs that extend toward the side of stringer;
FIG. 6 is a side perspective view showing the blocking device of the present invention assembled with a ladder and blocking access to a tree stand in the field;
FIG. 7 is a bottom view of an alternate embodiment of the invention in which a shield is supported by the prongs;
FIG. 8 is a top view depicting the shield of an alternate embodiment of the invention;
FIG. 9 is a front view of the blocking device of alternate embodiment attached to the ladder;
FIG. 10 is a side perspective view showing the blocking device of the alternate embodiment assembled with ladder and blocking access to a tree stand in the field; and,
FIG. 11 is a top perspective view of a second alternate embodiment of the ladder blocking device with the prongs removed attached to and supported by a ladder;
FIG. 12 is a front view of the embodiment seen in FIG. 11; and,
FIG. 13 is a top view of a third alternate embodiment of the ladder blocking device attached to and supported by a ladder.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical structural elements of the invention. It also should be appreciated that figure proportions and angles are not always to scale in order to clearly portray the attributes of the present invention.
While the present invention is described with respect to what is presently considered to be the preferred embodiments, it is understood that the invention is not limited to the disclosed embodiments. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be appreciated that the term “substantially” is synonymous with terms such as “nearly”, “very nearly”, “about”, “approximately”, “around”, “bordering on”, “close to”, “essentially”, “in the neighborhood of”, “in the vicinity of”, etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term “proximate” is synonymous with terms such as “nearby”, “close”, “adjacent”, “neighboring”, “immediate”, “adjoining”, etc., and such terms may be used interchangeably as appearing in the specification and claims. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.
Adverting to the drawings, FIG. 1 is a top view of one embodiment of the ladder blocking device 10 (“device 10”) of the present invention. Device 10 includes first support 12 (support 12″) which holds a plurality of prongs 14 that extend from first support 12 at an angle in relation to support 12. In an alternate embodiment, device 10 also comprises second support 12a (“support 12a”) (collectively “supports 12”). As seen at least in FIG. 1, support 12 and support 12a may be joined to form one unit support 12. In the embodiment shown, the two components of support 12 may be pivotably joined at pivot point 16. In the drawing shown, bolt 16a forms the pivotable joint. In other embodiments, the pivotable joint may be a hinge or other joint well known to persons skilled in the art. Preferably, notches 18 are formed in supports 12 to enable each support 12 and 12a to fit around the stringers 32 of the blocked ladder 30 (not shown in FIG. 1). Supports 12 and 12a may be attached directly to ladder 30 directly such as by welding or bolting one or more of supports 12 to ladder 30 or indirectly such as by resting device 10 on a ladder rung while in a closed position with notches 18 fitted around the stringers of ladder 30 thereby holding device 10 on ladder 30.
FIG. 2 is a top view depicting device 10 attached to and supported by ladder 30. Device 10 is supported by one of the plurality of rungs 34 and extends to each of the two parallel stringers 32 of ladder 30. Notches 18 fit around each stringer 32 to hold device 10 in position on ladder 30. Prongs 14 extend separately outwardly and downwardly from support 12 and support 12a (not seen in FIG. 2) so that both sides of ladder 30 are blocked from an unauthorized user. Although two supports 12 are shown in FIG. 2, persons having skill in the art will recognize that only a first support 12 may be needed to block use of ladder 30 if the ladder is positioned close to a building or other structure so that there is insufficient space for a user to climb up the unblocked side of ladder 30. FIG. 3 is a front view of blocking device 10 attached to ladder 30 showing how support 12 and support 12a overlap each other on the same rung 34.
FIG. 4 is a partial side perspective view of the combined ladder 30 blocking device 10 assembly showing a lock 40 holding supports 12 together. Although a padlock 40 is shown, persons of skill in the art will recognize that other locking mechanisms, such as but not limited to, combination locks or a locked cable, may be used to lock supports 12 together.
FIG. 5 is an enlarged partial top view of the invention in which each of support 12 and support 12a includes additional prongs 15 that extend toward the side of stringer 32 so as to obstruct users from bypassing device 10 by climbing outside one of the stringers 32. In the embodiment shown, side prongs 15 are shown in shaded lines as attached to, such as by using welds, supports 12 and/or support 12a. In this embodiment, blocking device 10 may be easily carried to the ladder 30 even with side prongs 15 included on each of supports 12 and 12a.
FIG. 6 is a side perspective view showing blocking device 10 assembled with ladder 30 blocking access to tree stand 50 in the field. Tree stand 50 is shown with hatch 52, seat 54, and roof 56. It can be seen that device 10 effectively blocks access to hatch 52 as the prongs 14 and 15 extending separately outwardly and downwardly from support 12 act to prevent a user from bypassing device 10. (Not shown is support 12a although prongs 14 can been extending separately and outwardly and downwardly between ladder 30 and tree T.) In this regard, prongs 14 and 15 can be any suitable length. In one embodiment, prongs 14 and 15 are at least 8 inches in length. In an alternate embodiment, prongs 14 and 15 are at least 13 inches in length.
FIG. 6 portrays the advantages of blocking device 10 over the prior art. Device 10 of the present invention can be placed higher up on ladders, creating a precarious situation for unauthorized users attempting to bypass the device. In addition, each support 12 and 12a is smaller and less cumbersome than an effective rung cover and thus easier to carry to the desired location, especially if that location is in a wilderness area. Moreover, the person attaching device 10 to ladder 30 can climb ladder 30 and attach it to the desired rung then lock it. In contrast, to extend a rung cover high enough on a ladder to be effective, a second ladder is necessary to raise the cover high enough to prevent a user from bypassing the rung cover after which the second ladder must be removed from the site.
In a bottom view of an alternate embodiment, FIG. 7 depicts ladder blocking device 100 (“device 100”) with a plurality of prongs 114 supporting shield 150. As seen in
FIG. 7, shield 150 may be formed from two half shields, 150a and 150b that can be closed around pivot point 116 to form a complete shield 150. Half shields 150a and 150b do not have to be attached to each other to form an effective blocking shield as shown in FIG. 8 below. Device 100 may include first support 112 (support 112″) which holds a plurality of prongs 114 that extend from first support 112 at an angle in relation to support 12. In an alternate embodiment, device 10 also comprises second support 112a (“support 112a”) (collectively “supports 112”). Similar to support 12 seen in FIG. 1, support 112 and support 112a may be joined to form a single support 112. In the embodiment shown, the two components of support 112 may be pivotably joined at pivot point 116 forming a complete shield 150 that blocks both sides of ladder 30. In the drawing shown, bolt 116a forms the pivotable joint. In other embodiments, the pivotable joint may be a hinge or other joint well known to persons skilled in the art. Preferably, notches 118 and 118a are formed in supports 112 to enable each support 112 and 112a to fit around the stringers 32 of the blocked ladder 30 (not shown in FIG. 7). Supports 112 and 112a may be attached directly to ladder 30 such as by welding or bolting one or more of supports 112 to ladder 30 or indirectly such as by resting device 10 on a ladder rung while in a closed position with notches 118 and 118a fitted around the stringers of ladder 30.
Shield 150 may be fabricated from different material as long as it is durable and possesses sufficient strength to maintain structural integrity if people attempt to climb over it, cut it, or otherwise try to bypass it. Examples of appropriate fabrication materials include, but are not limited to steel, stainless steel, aluminum and some forms of carbon fiber reinforced polymer (CFRP). Persons of skill in the art will recognize that other suitable materials may be used to fabricate shield 150.
FIG. 8 is a top view depicting shield 150 (shown by the shaded line) of blocking device 100 attached to and supported by prongs 114. In this view, device 100 is attached to and supported by ladder 30. Device 100 is supported by one of the plurality of rungs 34 and extends to each of the two parallel stringers 32 of ladder 30. Notches 118 and 118a form combined notch 118 that fit around each stringer 32 to hold device 100 in position on ladder 30. Prongs 114 extend from support 112 and support 112a (not seen in FIG. 8) so that both sides of ladder 30 are blocked from an unauthorized user. Side prongs similar to prongs 15 may be included in device 100. Shield 150 may be attached to one or more of prongs 114 by using spot welds and certain adhesives and other methods known in the art can be used to form permanent attachments to prongs 114. Nut and bolt assemblies may be used.
Although two supports 112 are shown in FIG. 8, persons having skill in the art will recognize that only a first support 112 with shield 150a may be needed to block use of ladder 30 if the ladder is positioned close to a building or other structure so that there is insufficient space for a user to climb up the unblocked side of ladder 30. FIG. 9 is a front view of blocking device 10 attached to ladder 30 and depicting the shield 150 extending downwardly and outwardly from supports 112 and 112a.
FIG. 10 is a side perspective view showing blocking device 100 assembled with ladder 30 blocking access to tree stand 160 in the field. Tree stand 160 is shown with hatch 162, seat 164, and roof 166. It can be seen that shield 150 of device 100 effectively blocks access to hatch 162 as shield 150 acts to prevent a user from climbing around device 100. In one embodiment, prongs 114 and shield 150 are at least 8 inches in length. In an alternate embodiment, prongs 114 and 115 are at least 13 inches in length. In this regard, prongs 114 and side prongs 115 (if present) can be any suitable length to support shield 150 while shield 150 may extend farther than the length of prongs 114 and/or prongs 115s.
FIG. 11 is a top perspective view of still another embodiment of the invention in which ladder blocking device 200 (“device 200”) is attached to a supported by ladder 30. It will be noted that device 200 does not include the plurality of prongs seen in devices 10 and 100. In other words, device 200 is supported by supports 212a and 212b to form support 212 which is analogous in structure and function to supports 12 and 112 discussed above. As indicated by pivot end 216 and locked end 240, device 200 comprises two halves 200a and 200b with attached supports 212a and 212b, respectively. When pivoted closed on hinge 210, supports 212a and 212b together form support unit 212 which rests on one of rungs 34 of ladder 30. In a preferred embodiment, each of supports 212a and 212b includes notches 218a and 218b, respectively which wrap around stringers 32 to releasably attach device 200 more securely to ladder 30.
FIG. 12 is a bottom view of the embodiment seen in FIG. 11 again lacking the supportive prongs. More clearly seen in this view is hinge 210 which extends along the width of shield 200 to facilitate closing the two shield halves, 200a and 200b, respectively.
FIG. 13 is a top view of a third alternate embodiment of the ladder blocking device seen supported by ladder 30. Ladder blocking device 300 (“device 300”) is a modification of the d-ring discussed above. Device 300 comprises two d-ring shaped shields 300a and 300b, respectively. The straight edges of the shields each are shaped into supports 312a and 312b, respectively, joined at pivot point 316 joined by pivot bolt 316a. When the two shields are closed support 312 is formed by supports 312a and 312b and is supported by one of rungs 34 on ladder 30. Hasp 340 holds device 300 closed on the side opposite pivot point 313. Notches 318 wrap around stringers 32 to hold device 300 in place.
In the embodiment depicted in FIG. 13, support 312 extends outside each of ladder stringers 32 with shields 300a and 300b attached to respective supports 312a and 312b. This configuration creates a space S between rung 34 and each of the inner edges of the semicircular d-ring shaped shields 300a and 300b. Device 300 may be manufactured from the same or similar material discussed above and has the advantage of weighing less than blocking devices fabricated from similar material thus making it easier to handle. Shields 300a and 300b may extend horizontally, at a downward angle, or at an upward angle from supports 312a and 312b, respectively.
Thus it is seen that the objects of the invention are efficiently obtained, although changes and modifications to the invention should be readily apparent to those having ordinary skill in the art, which changes would not depart from the spirit and scope of the invention as claimed.
Patent Grant
11692395
