Fire escape – ladder – or scaffold – Door and ladder
Reexamination Certificate
2000-07-18
2003-12-16
Lev, Bruce A. (Department: 3634)
Fire escape, ladder, or scaffold
Door and ladder
C182S078000
Reexamination Certificate
active
06662901
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to apparatus for controlling the movement of a folding ladder or stairway, and more particularly, to an apparatus with a pivoted control arm to control the raising and lowering of a ladder or stairway of the type used in ceiling structures in a building.
2. Description of the Prior Art
Folding ladders or stairways are well known in the art and are frequently used in ceiling structures of buildings to provide access to attic space or upstairs rooms. Thus, these may be referred to as folding, disappearing attic ladders or stairways. Typically, such a ladder is mounted on a hinged door which fits in a framed opening in the ceiling. The ladder is folded and unseen when the door is closed and is unfolded to extend down to the floor when the door is open.
In one type of folding ladder, there are three ladder sections. A first section is fixedly attached to the door, a second section is hingedly connected at one end to the lower end of the first section, and a third section is hingedly attached to the other end of the second section. When folded, the second section is immediately adjacent to the first section, and the third section is immediately adjacent to the second section such that all sections are substantially parallel to one another. When unfolded, the sections are substantially aligned to form the ladder or stairway. Examples of such devices are manufactured by Bessler Stairway Company, Werner Co., American Stairways, Inc., The Marwin Company, and Davidson. Another example of such a folding stairway or ladder is shown in U.S. Pat. No. 2,649,237 to Bjorklund et al. These ladders usually are made of wood or metal, such as aluminum. The material of the ladder is unimportant to the present invention, however.
In these folding ladders, the door is pivotally connected at one end to a ceiling joist or other part of the building structure, and the other end of the door has a cable attached thereto which extends from the outer side of the door. The door is spring loaded to bias it toward a closed position. By pulling on the cord, the door is pivoted on the hinges and moved to an open, angularly disposed position with respect to the ceiling. The operator must then manually grasp the second or third section of the ladder to pivot the second and third sections downwardly to the unfolded operating position of the ladder. This is frequently difficult to do, particularly in high ceiling areas and for persons of short stature. The operator may have to jump up to grasp the ladder to unfold it. There is also some awkwardness in the fact that the spring tends to close the door while the operator is attempting to unfold the ladder. It is possible that the door may swing upwardly without warning while the operator's hand is extended into the ladder. Also, the ladder sections may pivot downwardly unexpectedly when lowering the ladder, causing one or more of the ladder sections to strike the operator. In fact, this latter problem has resulted in at least one fatality. All of these dangers are exacerbated if the operator has to jump to try to reach the ladder.
Therefore, there is a need for an apparatus to control the folding and unfolding of the ladder so that if a portion of the ladder pivots unexpectedly, the operator is at a safe distance from the ladder, thereby minimizing the possibility of injury. The present invention solves this problem by providing a ladder control apparatus with a pivoted control arm which allows the operator to manipulate the ladder sections while standing a safe distance from the ladder. Also, the operator can use both hands in a comfortable position to more positively control the movement of the ladder sections.
SUMMARY OF THE INVENTION
The ladder control apparatus of the present invention comprises a control base portion attachable to a folding ladder or stairway and a control arm portion pivotally connected to the base portion, whereby an operator of the apparatus may manipulate the ladder between folded and unfolded positions thereof while the operator is positioned away from the ladder. Preferably, the arm portion may be pivoted in substantially any direction with respect to the base portion, such as by connecting the arm portion to the base portion with a rod end pivot assembly or a ball and socket pivot assembly.
The apparatus further comprises means for retaining a distal or free end of the arm portion when the arm portion is not in use by the operator. In one embodiment, this means for retaining means comprises a spring biased clamp attachable to the ladder. The clamp resiliently retains the distal end of the arm portion.
In the preferred embodiment, the arm portion is a telescoping arm portion having a variably extended operating position. The apparatus further comprises locking means for locking the arm portion in a selected extended operating position. The locking means may comprise a locking ring and a rotatable collar adapted for compressing the locking ring.
Stated in another way, the apparatus of the present invention is adapted for controlling a folding ladder or stairway and comprises a base attachable to a section of the ladder and extending from a side rail thereof, and an arm having a proximal end pivotally attached to the base and a distal end by which an operator may exert pulling and pushing forces on the ladder to move it between folded and unfolded positions thereof The arm comprises an outer arm portion and an inner arm portion telescopingly received in the outer arm portion.
The present invention also includes a ladder apparatus for use in an opening in a building structure. The ladder apparatus comprises a plurality of ladder sections substantially parallel to one another when in a folded position and substantially aligned with one another when in an unfolded position. Each of the ladder sections has a pair of spaced side rails and a plurality of treads extending between the side rails. One of the ladder sections is adapted for pivotal connection with respect to the building structure adjacent to the opening therein. This ladder apparatus further comprises a control base attached to another of the ladder sections, and a control arm having a proximal end pivotally attached to the control base and a distal end adapted for gripping by an operator whereby force may be applied to the other of the ladder sections to move the ladder between folded and unfolded positions thereof The arm may be pivoted with respect to the side rail of the other of the ladder sections.
The ladder apparatus may further comprise a clamp attached to the other of the ladder sections and spaced from the control base. The clamp is adapted for grippingly retaining the distal end of the arm in a stored position when the arm is not in use by the operator.
The arm of the ladder apparatus comprises an outer arm portion and an inner arm portion telescopingly received in the outer arm portion such that a length of the arm may be selectively varied by the operator. A lock may be provided for locking the inner and outer arm portions with respect to one another when the arm is at a desired length. The lock may comprise a locking ring extending from the outer arm portion and disposed around the inner arm portion, and a collar threadingly connected to the locking ring. The collar is adapted for compressing the locking ring into locking engagement with the inner arm portion when the collar is rotated with respect to the outer arm portion. Other locking arrangements could also be used.
REFERENCES:
patent: 453294 (1891-06-01), Powers
patent: 1721521 (1929-07-01), Marschke
patent: 1767148 (1930-06-01), Marschke
patent: 2163142 (1939-06-01), Frazier
patent: 2506380 (1950-05-01), Myers
patent: 2595597 (1952-05-01), Morseth
patent: 2649237 (1953-08-01), Bjorklund et al.
patent: 2815159 (1957-12-01), Harmon
patent: 3375044 (1968-03-01), Peterson
patent: 3982608 (1976-09-01), Booth
patent: 5050706 (1991-09-01), Cole et al.
patent: 5649780 (1997-07-01), Schall
patent: 5685659 (1997-11-01), Brosius et al.
Brochu
Lev Bruce A.
McAfee & Taft
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