Patent Application
20140144006
The present invention relates generally to building equipment, and more particularly to ladder cages for use with scaffolding and other structures.
Tall structures such as communications towers, wind turbines, scaffolding, and the like are often equipped with a ladder that may be climbed to reach points of elevation on the structure, for service or the like. Often, such ladders provide the only easy access to these points of elevation. As well, the ladders typically extend completely vertically, to significant heights and present a risk to a climber.
As such, these ladders are often surrounded by generally semi-circular rings, affixed at either side of the ladder typically along the extent of the ladder, Vertical bars extend between the rings. The rings and bars define a ladder cage, and provide security for the climber to inhibit a downward or outward fall away from the ladder.
Typically, these rings are securely affixed to the ladder, and as such are not easy to install and cannot be easily moved or removed. For some structures, however, easy removal and installation are desirable.
As such, there remains a need for a ladder cage assembly that may be easily installed and removed.
In accordance with an aspect of the present invention, there is provided a ladder cage comprising: a plurality of spaced rings, having fasteners attached thereto; a plurality of vertical braces, each having a mounting hole proximate each end, and extending between two of the plurality of rings, and attached at either end to respective ones of the fasteners; wherein each of the fasteners comprises a mounting pin having a slot therein, and a drop pin slidably mounted to that fastener for sliding in and out of its slot in its mounting pin; and wherein an associated vertical brace is fastened to a ring by that fastener, as its mounting pin is received in the mounting hole of the associated vertical brace, and the drop pin of the fastener is received in the slot of said mounting pin, wherein the drop-pin makes an angle of between about 30° and 60° to the vertical.
In accordance with another aspect of the present invention, there is provided a ring for forming a ladder cage comprising: a ring shaped body having fasteners attached thereto; each of the fasteners comprising a mounting pin having a slot therein, and a drop pin slidably mounted to that fastener for sliding in and out of its slot in its mounting pin, wherein the drop pin is mounted so it may make an angle of between 30° and 60° to the vertical; and wherein an associated vertical brace may be fastened to the ring by that fastener, as its mounting pin is received in the mounting hole of the associated vertical brace, and the drop pin of the fastener is received in the slot of the mounting pin.
In accordance with yet another aspect of the present invention, there is provided a method of assembling a ladder cage comprising: attaching two spaced rings having fasteners attached thereto to a ladder; each of the fasteners comprising a mounting pin having a slot therein, and a drop pin slidably mounted to that fastener for sliding in and out of its slot in its mounting pin, wherein the drop pin is mounted at an angle of between about 30° and 60° to a plane of its ring; attaching a vertical brace to the two spaced rings by inserting a mounting pin of corresponding ones of the fasteners on each of the two spaced rings into a hole of the vertical brace; and sliding a drop pin mounted to each of the corresponding one of the fasteners to rest at an angle of between 30° and 60° to the vertical into a slot in their mounting pins to fasten the vertical brace to the ring by the fastener on each of the two spaced rings.
Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
In the figures which illustrate by way of example only, embodiments of the present invention,
Cage 10 includes several rings 14-1, 14-2, 14-3, . . . 14-n (individually and collectively rings 14—only three are illustrated in
Vertical braces 16 are typically identical, having like dimensions. For convenience, vertical braces 16 in a section 18—i.e. between the same two rings 14—are identified with a common subscript in
As illustrated in
As more particularly illustrated in
Each fastener 30 serves to secure one or two vertical braces 16 to a ring 14. For a ring 14 shared by two sections 18 of cage 10, a single fastener 30 receives an upwardly extending vertical brace 16, and a downwardly extending brace 16, as best illustrated by the enlarged portion of
An example fastener 30 for fastening brace 16 to ring 14 is more particularly illustrated in
As further illustrated in
Fastener 30 is mounted to ring 14, so that U-shaped drop pin 40 slides at an angle of about α=45° to the vertical (i.e. at an angle α to the plane of ring 14). In this way, U-shaped drop pin 40 is naturally pulled by gravity into slot 36. Once drop pin 40 is slid into slot 38, it locks one or more braces 16 into place on pin 32, preventing brace 16 from sliding off pin 32. Likewise, the size and angled orientation of U-shaped drop-pin 40, provides clearance for both an upwardly and downwardly extending brace 16 to be received on pin 32. As will now be appreciated, mount angles of less than or more than 45° may achieve the same effect. The mount angle may be any angle which provides sufficient clearance for braces 16, given the geometry of drop pin 40, and that result in a sufficient downward pull of drop pin 40 into slot 36 by gravity. For example, angles of between 30° and 60° may be appropriate.
Conveniently, ring 14 with fasteners 30 allow for relatively quick assembly of ladder cage 10. Two adjacent rings 14 may be attached to ladder 12, and braces 16 may be attached to these rings 14. U-shaped drop pins 40 may be quickly and readily slid between the open and closed position of fastener 30, to allow for easy installation of braces 16. At the same time, the effect of gravity biases U-shaped drop-pins 40 closed. With the aid of gravity, use of cotter-pins 52 is optional.
Ladder cage 10 may similarly be disassembled, to allow easy removal, by sliding U-shaped drop pins 40 upward, providing clearance to allow the flattened ends 28 of braces 16 to be slid outward, off of pins 32. Once braces 16 are removed from rings 14, rings 14 may be removed from ladder 10.
As will be appreciated U-shaped drop pins 40 could be replaced with drop pins of another shape—for example linear drop pins could be used.
pun In an alternate embodiment, fastener 30 (and hence drop pin 40) could be mounted to ring 14 so that it may be rotatable or pivotal about an axis of pin 32. The drop pin 40 could be rotated to an arbitrary angular position as braces 16 are installed. For example, to suit a particular application or the preference of an installer, fastener 30 could be rotated so that drop pin 40 is in a substantially horizontal orientation, parallel to the plane of ring 14, as the braces 16 are installed. Thereafter, the pin could be rotated to make a suitable angle with the vertical to lock drop pin 40 with the aid of gravity after brace(s) 16 is/are installed
Of course, the above described embodiments, are intended to be illustrative only and in no way limiting. The described embodiments of carrying out the invention, are susceptible to many modifications of form, arrangement of parts, details and order of operation. The invention, rather, is intended to encompass all such modification within its scope, as defined by the claims.
