Patent Application
20070051934
The present invention relates generally to the field of safety gates and, more particularly, to a spring biased safety gate having a removable or movable jam plate which determines the resting position of the safety gate.
In many industrial plants, catwalks or catwalks provide access for workers to traverse from one area of the plant to another. For example, such catwalks provide access to various equipment throughout the plant. Unfortunately, the catwalks also provide locations from which a worker could fall to a lower level. In order to make them safer, such catwalks are commonly provided with guard rails to help prevent a worker from accidentally stepping off the side of the catwalk and falling. For various reasons, however, it is necessary to provide openings in the guard rails. Usually, for example, one or more ladders or stairs lead from the catwalk to a lower level. Openings are provided in the guard rails so that a person can move from the ladders or stairs onto the catwalk and vice versa. Such openings in the guard rails may present a danger to personnel using the catwalk.
In my U.S. Pat. No. 6,684,566, I taught a spring-biased safety gate with a guard plate which was mounted to a gate member with the same hardware that mounts the stop to the gate. The guard plate was preferably formed of plate metal to define a plate mounting area and a pair of guard plates that extend perpendicularly from either side of the plate mounting area. In that way, each of the pair of guard plates extended in a direction parallel to the gate a distance sufficient to shield the mounting hardware behind the guard plate and the stop. A stop is provided to stop the rotation of the gate member in the biased direction when the gate member is in position to close the opening to personnel on the catwalk. The stop comprised a portion of the mounting plate extending laterally a sufficient distance to contact a bolt mounted on the gate member by nuts and by a washer, joined to the spacer plate.
The safety gate taught in the '566 patent has been a commercial success, but lacks features that are desirable in certain applications. Often, the structure and arrangement of a particular catwalks will call for a safety gate which may be positioned in either of two positions, one at 90° to the railing on which the gate is mounted, and one extending in the same general direction as the railing. The stop which is shown and described in the '566 patent is not well adapted to accomplish such an adjustment. In U.S. Pat. No. 6,094,863, Hardy L. LaCook, Jr. taught an attachment for a safety gate that was positioned to close the opening in a catwalk to allow access to and from a ladder or stairs. This safety gate included a stop which in all relevant respects was similar that that just described.
In U.S. Pat. No. 3,866,356, LaCook et al. taught an earlier version of a safety gate for closing the openings for ladders or stairwells in the guard rails of catwalks. A spring urged the gate member to rotate in one direction and a stop limited the rotation in that direction to position the gate member to close the opening. The stop was adjustable as previously described so that the gate member could be positioned as required by location of the opening relative to the guard rail.
Thus, there remains a need for a simple structure by which a safety gate may be adapted to be positioned at either of two stopped positions. The present invention is directed to fulfilling this need in the art.
The present invention addresses these and other needs in the art by providing a movable or removable plate which is mounted adjacent to the pivot point of the gate mounting structure. The plate is shown and described herein as affixed to the gate, but those of skill in the art will recognize that the plate may as easily be mounted to the railing structure for abutting contact with the gate. Further, as used herein and particularly in the claims to follow, the term “removable” means that the plate may be placed in an abutting arrangement or removed therefrom, either by removing the plate from the gate structure or by moving the plate away from an abutting arrangement, while still remaining attached to the gate structure. This is in contrast to the stop structures described above which maintain a bolt-type stop in an abutting arrangement at all times when the gate is at a rest position.
The plate may include a set of circular holes adapted to receive mounting bolts. In order to cause the gate to remain in a first position, the plate is installed with bolts through the circular holes. If the gate is to remain in a second position, preferably extending parallel to a railing to which the gate is mounted, then the plate is removed.
In another preferred embodiment, the plate may include a pair of L-shape slots to receive the bolts. In this embodiment, if the gate is to be positioned to the first position, then the plate is placed at a first position. When the gate is to be positioned at the second position, the bolts is loosened, the plate is slid back with the bolts sliding along the L-shaped slots, and the gate is positioned by a biasing means such as a spring to the second position.
These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached drawings and appended claims.
The swinging gate member 12 includes an upper horizontal bar 18 and a lower horizontal bar 20. A vertical structural support beam 22 extends between the upper horizontal bar 18 and the lower horizontal bar 20. The vertical structural support beam 22 lends mechanical stiffness to the swinging gate member 12, but is primarily included to receive a removable plate 24. The removable plate 24 is releasably secured to the vertical structural support beam with one or preferably more bolts 26.
The removable plate of
With the removable plate 24 installed as illustrated in
The safety gate 10 just described thus provides a safety barrier between a railing 32 and a railing 34 which may have a wide variety of orientations and structures. The safety gate may also be mounted to a railing in which the opening is perpendicular to the orientation illustrated in
As shown in
Finally,
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. Because many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
