Ladder with safety device

The ladder safety device is for blocking access to the lower rungs of a portable extension ladder. During use, the ladder may have to remain positioned against a structure in that it is part of the temporary scaffolding or for other reasons. In one embodiment, a container having a width slightly less than the width between the side rails is positioned on a higher rung by a pair of hooks. A slot in the container has one end of a flexible panel extending therefrom with hooks thereon. The panel is unwound upon a controllable shaft when pulled from the container and the lower hooks are attached to a lower rung. A locking device must be activated to allow for the removal of the lower hooks and then the retraction of the panel into the container. The device may be incorporated into the rung.

CROSS-REFERENCES TO RELATED APPLICATIONS

REFERENCE TO FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

REFERENCE TO JOINT RESEARCH AGREEMENTS

REFERENCE TO SEQUENCE LISTING

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to devices for climbing, and, in particular, relates to ladders, and, in greater particularity, relates to devices for preventing unauthorized climbing thereon.

Description of the Prior Art

The use of devices for accessing heights above one's reach are well known. This problem occurs both in a residential and construction settings. One device of general use is the folding step ladder or extension ladder. The typical extension ladder is made of aluminum, but fiberglass is also used. The extension ladder combines two sliding sections together. The extension ladder is about 1.5 feet in width, can range in height up to 30 or more feet, and with rungs about 1 foot apart. When left in the standing position, it presents an attractive nuisance to children, in particular, but others may attempt to use the ladder to gain access to a building and remove construction materials. This problem has been addressed by several devices as noted below.

The Accuform Signs ladder shield kit shows a flexible panel secured to ladder rungs by a cable and lock through grommets in the panel back. The panel rolls up on itself when not in use.

Several Patents Address this Problem:

U.S. Pat. No. 7,717,231 shows a ladder guard having a plurality of panels that overlap to prevent the use of the rungs and can be adjusted to allow the use of the rungs. It is connected to the ladder when not in use. The additional weight at one end of the ladder may cause it to become unstable when being moved.

U.S. Pat. No. 5,575,353, although not being a ladder invention, shows a device like for use in blocking the use of stairs in a house with a flexible sheet thereon deployed therefrom. Adjustable rods like in shower curtains allow for placement on stair side rails of varying widths.

U.S. Pat. No. 5,441,126 shows a semi-rigid shell placed over the front of extension ladder sections and temporarily deployed thereon.

U.S. Pat. No. 5,421,428 shows a metal sheet covering rungs and hooked over a top and bottom rung.

U.S. Pat. No. 4,126,206 shows two sheets placed over rungs and locked thereto to prevent access.

All references are incorporated herein as to their teachings.

Accordingly, there is a need for a device for use upon extension ladders that is readily available for use and can be stored thereon without interference with climbing thereon.

SUMMARY OF THE INVENTION

The present invention is directed at extension ladders and preventing access thereon when setup.

The present invention in one embodiment provides a portable ladder safety device for blocking access to the lower rungs of a portable extension ladder. During use, the ladder may have to remain positioned against a structure in that it is part of the temporary scaffolding or left in position for other reasons. Once the ladder is positioned, the portable ladder safety device is used as necessary. The ladder safety device may be permanently attached or removable when not in use. A container thereof has a pair of hooks that are placed over an upper rung. A flexible panel is pulled from the container onto and over the exposed lower rungs and a pair of lower hooks are attached to a lower rung that are permanently attached to the lower end of the panel. The flexible panel automatic retracts to remove any excess panel. A locking mechanism in the container prevents the panel from being removed or moved once locked.

In another embodiment, the container may be attached to an upper run by the manufacturer of the ladder and sold as a unit thereon. It may also be an integral part of a ladder rung. The container would have a width slightly less than the width between the side rails. A slot in the container has one end of a flexible panel extending therefrom with hooks thereon. The panel is unwound upon a controllable and lockable shaft when pulled from the container and the lower hooks are attached to a lower rung. A release device must be activated to allow for the removal of the lower hooks and then the retraction of the panel into the container.

One object of the present invention is to provide a ladder safety device to prevent unauthorized access to a setup ladder.

It is another object of the present invention to provide a ladder safety device that is a separately purchased unit and attached to the ladder when used and as needed.

It is a further object of the present invention to provide a ladder safety device that is attached to a purchased ladder.

It is still a further object of the present invention to provide a ladder safety device that is secured by a lock.

It is yet a further object of the present invention to provide a ladder safety device that further may have warnings and advertisement thereon.

It is yet a further object of the present invention to provide a ladder safety device that employs the use of a rotatable biased shaft or a manually turned shaft having the panel thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a ladder safety device for preventing the unauthorized access to a positioned ladder.

In general, the present invention in one embodiment provides a portable ladder safety device for blocking access to the lower rungs of a portable extension ladder. Once the ladder is positioned, the portable ladder safety device is attached. A container of the ladder safety device has a pair of hooks that are placed over an upper rung. A flexible panel, is pulled from the container onto and over the exposed lower rungs and a pair of lower hooks are attached to a lower rung. The flexible panel may automatically retract to remove any excess panel or is manually moved. A locking mechanism in the container prevents the panel from being removed thereafter.

In general, in another embodiment, the container is attached to an upper rung by the manufacturer of the ladder and sold as a unit thereon. It may also be an integral part of a ladder rung. The container would have a width slightly less than the width between the side rails. A slot in the container has one end of a flexible panel extending therefrom with hooks thereon. The panel may be unwound upon a controllable, spring biased, and lockable shaft when pulled from the container and the lower hooks are attached to a lower rung. The panel itself may be made of fabric, plastic or metal and have a length approximately of about 5 feet. A release device must be activated to allow for the removal of the lower hooks and then the retraction of the panel into the container.

Referring toFIG. 1, an extension ladder10is of conventional design and shown in traverse cross section. The extension ladder10may be made of aluminum or fiberglass. The invention further may be adapted to a folding step ladder. The ladder10has a first ladder section12that normally rests upon the ground or other solid object when positioned. The side rails14and16are “I” shaped with a rung18therebetween. Attached to the first ladder section12is a second ladder section20of similar design by the outside edges22are in sliding engagement/attachment to the first ladder section12. The edges22are positioned under the inside edges24of the first ladder section12. Slide locks26being two rotate upon pins28. A lower edge30of the slide lock26has a lip32that fits over a rung18. This prevents the second ladder section20from sliding downward when stood upright. To move the second ladder section20higher, the second ladder section20is moved slightly upwards so that the slide locks26can be rotated away so that the lips32are not engaged with the rung18. When released, the slide locks26rotate inward and will engage the rung as it is lowered.FIG. 2is a longitudinal cross section through one rung18and shows the rung slanted side34for a footstep. The operation of the extension ladder10is well known to one skilled in the art.

FIG. 3shows a front view and a side view of the ladder safety device36having means for connecting38the ladder safety device36to a ladder10; the ladder safety device36has a container40with a flexible panel therein or which can be unreeled therefrom. The container40would be made of metal or plastic and shaped as a rectangular or cylindrical container. The flexible panel44may be about 12 inches wide or so, made of a fabric like canvas, plastic or metal, and with a length of about five feet. The container40inFIG. 3has a traverse slot76therein from which the flexible panel44extends. Within the container40is a lockable means42,FIG. 4, mounted therein for controlling the flexible panel44. A rotatable biased shaft46,FIG. 5, may also be mounted in the container40and the flexible panel44has on one end mounted to the rotatable biased shaft46with the lockable means42engaging the rotatable biased shaft46in a predetermined manner as shown inFIG. 4and is typically mounted on one end of the rotatable based shaft46.

FIG. 7illustrates an embodiment where the rotatable biased shaft46is replaced by a manually turned shaft80wherein an external wheel82may be rotated. The shaft80is also engaged with a lockable means42as described below.

FIG. 4illustrates a lockable means42. A keyed lock60is mounted in the container40. When the key, not shown, is turned counterclockwise, a lever62rotates upward against a pivoted shaft/arm64. The pivoted shaft/arm64is spring biased by spring68so that teeth66are normally engaged to a geared wheel70to prevent rotation. When the pivoted shaft/arm64rotates downward, the teeth66disengage from the wheel70and due to a spring bias of the rotatable biased shaft46,FIG. 5, the rotatable biased shaft46will always turn in a rotation to retract the panel if there are no forces counter the rotation such as a pulling action upon the panel44. After the lower hooks72are secured to a lower rung, the key is rotated clockwise so that the geared wheel70will not rotate further. At that point the panel44is pulled tight and can not be removed since the geared wheel70is held by the teeth66. To release the panel44, the key is again turned counter clockwise which allows the rotatable shaft46to rotate. The hooks72are pulled off of the rung and this allows the panel44to be retracted into the housing40. The ladder safety device can then be removed from the ladder. It is further possible to have the ladder safety device mounted on a lower rung and have the flexible panel44extend upwards.

The ladder safety device is used upon an extension ladder10, but can be adapted for use on other types of ladders.

In the first embodiment, the ladder safety device36connects to rung18of the ladder10; in another embodiment, the ladder safety device100is attached to a side rails14and16of the ladder100,FIG. 2, and in a third embodiment,FIG. 6, the ladder safety device90may be an integral part of a rung92.

In the first embodiment, the ladder safety device has means for connecting to the ladder10via hooking means. The hooking means comprises a first hooking means mounted on said container40, and a second hooking means mounted on the flexible panel44on an end opposite to the end mounted to the rotatable biased shaft46. In the first embodiment, the hooking means are a pair of hooks74on the container40and a pair of hooks72on the panel44. It should be understood that the ladder safety device may be mounted opposite to that discussed, for example, having the flexible panel extend upwards instead.

The rotatable biased shaft46is controlled by a key that is required to unlock the locking means as shown inFIG. 4. The key when turned rotates a lever to release the rotatable bias shaft46so as to allow the rotatable bias shaft46to turn for deploying the flexible panel or retracting the flexible panel.

In a second embodiment, a safe ladder100,FIG. 2, only partially shown, has the container80secured to the side rails and is sold as a unit. The elements of the safe ladder100are essentially the same as in the first embodiment except there are no top hooks74required. A third embodiment is shown inFIG. 6wherein the container40is merged into the structure of a “rung”. In a fourth embodiment as shown inFIG. 8, the container40may be secured to the ladder permanently by use of a pair of metal straps80, only one shown inFIG. 8. The straps may be bolted together or riveted such as used with the pulley. The container40may be mounted between the rails or behind the rails if attached to the lower rung and the panel may extend upwards instead. The panel would have a width slightly less than the width between the rails.