LADDER FOR EVACUATING PERSONS FROM CHAIR AERIAL CABLE LIFTS
United States Patent 3780829
A ladder for evacuating persons from chair aerial cable lifts comprising, a rigid ladder, an elongate hook support member, means for securing the lower end of the hook support member to at least one ladder rung and a hook which is substantially U-shaped in cross section attached to the upper end of the support member, the hook comprising an elongate outer end member and two spaced side members which combine to form a groove adapted to receive the cable of a lift, the longitudinal centerline of the groove extending substantially normal to the longitudinal centerlines of the rungs of the ladder when viewed from the top to cause the rungs of the ladder to be positioned substantially parallel to the front or forward end of a chair suspended from the cable and also to aid in preventing twisting of the ladder relative to the cable in use. In a preferred embodiment, a pair of semi-elliptical grooves are provided in the outer end member, one at each end thereof. In another preferred embodiment, the hook also comprises latch means for releasably closing the groove at a locality spaced below the elongate outer end member of the hook.
US Patent References:
Wrecking bar with ladder hook
Sorensen - April 1943 - 2316723
Ladder attachment
Chubbs - September 1959 - 2903086
Wrecking bar with ladder hook
Sorensen - April 1943 - 2316723
Ladder attachment
Chubbs - September 1959 - 2903086
Application Number:
05/301055
Publication Date:
12/25/1973
Filing Date:
10/26/1972
View Patent Images:
Export Citation:
Assignee:
Valley Engineering, Inc. (Gray, ME)
Primary Class:
International Classes:
E06C1/36; E06C1/00; E06C7/48; E06C1/36
Field of Search:
182/206,214 248/238,210
Primary Examiner:
Machado, Reinaldo P.
Claims:
I claim
1. A ladder for evacuating persons from a chair aerial cable lift which includes an aerial cable and a chair suspended therefrom with the forward end of its seat substantially normal to the longitudinal centerline of the cable when viewed from the top, said ladder comprising,
2. A ladder according to claim 1 wherein the sides of said spaced side members converge as they extend downwardly from said elongate outer end member.
3. A ladder according to claim 1 wherein the inner faces of said side members are spaced apart a substantially equal distance whereby said groove is substantially the same width throughout and said hook also comprises latch means for releasably closing said groove at a locality spaced below said elongate outer end member of the hook.
4. A ladder according to claim 3 wherein said latch means comprises an arm, one end of which is pivotally attached to one side member of the hook, a tooth member attached to the other end of said arm and normally extending transversely of said groove to close it and an actuating member attached to the other end of said arm and extending in the oposite direction from said tooth member.
5. A ladder according to claim 4 which also comprises spring means having one end attached to said actuating member and the other end attached to said one side member of the hook for normally biasing said tooth member to groove closing position.
6. A ladder according to claim 1 wherein said means for securing said hook support member to a ladder rung comprises a pair of spaced U-shaped members one at either side of said hook support member, bridging said rung and detachably secured to said hook support member and an elongate angle member extending transversely between said U-shaped members and positioned adjacent to said rung.
7. A ladder according to claim 6 which also comprises a plate member positioned between said rung and the adjacent side of said hook support member, the apex of said angle member being positioned adjacent to said plate member and said rung being positioned between the curved ends of the U-shaped members and the sides of the angle member.
8. A ladder according to claim 6 wherein the apex of said angle member is positioned against the curved ends of said U-shaped member and the sides of the angle member are positioned against said rung.
9. A ladder according to claim 1 wherein said elongate outer end member comprises a pair of semi-elliptical grooves, one at each end thereof.
1. A ladder for evacuating persons from a chair aerial cable lift which includes an aerial cable and a chair suspended therefrom with the forward end of its seat substantially normal to the longitudinal centerline of the cable when viewed from the top, said ladder comprising,
2. A ladder according to claim 1 wherein the sides of said spaced side members converge as they extend downwardly from said elongate outer end member.
3. A ladder according to claim 1 wherein the inner faces of said side members are spaced apart a substantially equal distance whereby said groove is substantially the same width throughout and said hook also comprises latch means for releasably closing said groove at a locality spaced below said elongate outer end member of the hook.
4. A ladder according to claim 3 wherein said latch means comprises an arm, one end of which is pivotally attached to one side member of the hook, a tooth member attached to the other end of said arm and normally extending transversely of said groove to close it and an actuating member attached to the other end of said arm and extending in the oposite direction from said tooth member.
5. A ladder according to claim 4 which also comprises spring means having one end attached to said actuating member and the other end attached to said one side member of the hook for normally biasing said tooth member to groove closing position.
6. A ladder according to claim 1 wherein said means for securing said hook support member to a ladder rung comprises a pair of spaced U-shaped members one at either side of said hook support member, bridging said rung and detachably secured to said hook support member and an elongate angle member extending transversely between said U-shaped members and positioned adjacent to said rung.
7. A ladder according to claim 6 which also comprises a plate member positioned between said rung and the adjacent side of said hook support member, the apex of said angle member being positioned adjacent to said plate member and said rung being positioned between the curved ends of the U-shaped members and the sides of the angle member.
8. A ladder according to claim 6 wherein the apex of said angle member is positioned against the curved ends of said U-shaped member and the sides of the angle member are positioned against said rung.
9. A ladder according to claim 1 wherein said elongate outer end member comprises a pair of semi-elliptical grooves, one at each end thereof.
Description:
BACKGROUND OF THE INVENTION
This invention relates to a ladder for evacuating persons from chair aerial cable lifts.
Chair aerial cable lifts are used extensively in the winter on ski slopes. In use of such lifts, accidents occur making it necessary to evacuate a person from the chair of the lift to prevent injury or loss of life. In one case, a woman failed to properly seat herself on a chair and found herself dangling by one arm from the chair a short distance beyond the loading platform and approximately 25 feet in the air. In another case, a girl, intending to disembark at an intermediate unloading station on a chair lift, found herself suspended by her scarf which had become entangled with the chair. While in each case the lift was stopped, serious problems of evacuating the persons from their predicaments were encountered and, in one case, ended in disaster.
While a common ladder may be erected from the snow-covered surface to the aerial cable so that an attendant may try to ascend it and assist the person to descend the ladder, this is unsatisfactory and dangerous because with the upper end of the ladder resting against the cable, the rungs of the ladder are parallel to the cable and normal to the front opening of the chair. This makes it difficult for the attendant to remove the person from the chair and difficult for the person to remove himself from the chair unassisted. Furthermore, with the legs of the ladder resting upon a slippery, snow-covered surface, the ladder is likely to move while in use either by sliding along the ground or by twisting relative to the cable and the chair.
Usually, there is only one attendant in attendance at the lift loading or unloading area so the ladder used to evacuate the person from the chair should be capable of being erected and used very quickly by a single attendant.
While the following United States patents disclose hooks for holding ladders upon buildings, they would not function satisfactorily for use in evacuating a person from a chair aerial cable lift:
Patent No. Date of Issue Inventor 143,112 Sept. 23, 1873 L.E. Ainsworth 246,658 Sept. 6, 1881 R. Bustin 312,908 Feb. 24, 1885 F. Shickle 526,438 Sept. 5, 1894 M. Croissant 580,454 April 13, 1897 P.J. Gates 1,018,877 Feb. 27, 1912 F.W. Chickering 1,036,482 Aug. 20, 1912 E.A. Fredeen 1,249,855 Dec. 11, 1917 C.R. Taylor 1,252,224 Jan. 1, 1918 W.E. Bittner 2,316,723 April 13, 1943 N.C. Sorenson
In addition to the above patents, U.S. Pat. Nos. 2,963,104 dated Dec. 6, 1960 to Roth and 3,001,603 dated Sept. 26, 1961 to Kraus disclose combined electrical conductor spreaders and ladder hangers but they would not function satisfactorily for use in evacuating a person from a chair aerial cable lift.
One object of this invention is to provide a novel ladder for evacuating a person from chair aerial cable lifts.
Another object is to provide such a ladder which may be erected to an aerial cable adjacent to the chair quickly by a single attendant.
A further object is to provide such a ladder which, when erected, presents the rungs of the ladder substantially parallel to the front or forward end of the seat of the chair to facilitate evacuating a person from the chair.
A still further object is to provide such a ladder which does not twist relative to the cable or the ground after it has been erected.
Another object is to provide such a ladder with a hook which permits variation of the angle of the ladder relative to the cable without loss of torsional support.
A further object is to provide such a ladder which includes a novel and efficient safety latch for use in fast erection of the ladder and in retaining the ladder in erected position during evacuation of a person from a chair lift.
Yet another object is to provide such a ladder with novel and efficient means for detachably and firmly securing a member which supports the hook to one or more rungs of a ladder so that the hook does not twist or turn relative to the ladder in use.
A still further object is to provide a novel ladder hook attachment for use with a ladder for evacuating persons from chair or other aerial cable lifts.
Another object is to provide such a ladder hook attachment which is durable, economical to manufacture and easy to install upon any rigid ladder.
Other objects and advantages will be apparent to persons skilled in the art from the following description.
In its broadest aspect, the invention comprises a ladder having a pair of rigid side rails, a plurality of spaced rigid rungs extending transversely between said side rails, means for rigidly securing the lower end of the hook support member to at least one ladder rung, and a hook which is substantially U-shaped in cross section rigidly attached to the upper end of the support member, the hook comprising an elongate outer end member and two spaced side members which combine to form a groove adapted to receive the cable of an aerial lift, the longitudinal centerline of the groove extending substantially normal to the longitudinal centerlines of the rungs of the ladder when viewed from the top. Consequently when the bottom of the groove is positioned upon the cable of an aerial lift the rungs of the ladder are positioned substantially normal to the longitudinal centerline of the aerial cable when viewed from the top and substantially parallel to the forward end of the seat of a chair suspended from the aerial cable.
In a preferred embodiment, the elongate outer end member comprises a pair of semi-elliptical grooves, one at each end thereof.
In another preferred embodiment, the sides of the spaced side members converge as they extend downwardly from the elongate outer end member.
Preferably the hook also comprises latch means for releasably opening and closing the groove at a locality spaced below the elongate outer end member of the hook. This latch means may comprise an arm, one end of which is pivotally attached to one side member of the hook, a tooth member attached to the other end of the arm and normally extending transversely of the groove to close it and an actuating member attached to the other end of the arm and extending in the opposite direction from the tooth member. Spring means is provided which has one end attached to the actuating member and the other end attached to one side member of the hook and this spring means normally biases the tooth member to groove closing position. A rope is attached to the actuating member for moving the arm about its pivotal connection to the side member, whereby the tooth member may be moved from groove closing position to open position to permit the hook to be quickly positioned about an aerial cable.
Preferably the means for securing the hook support member to a ladder rung comprises at least one U-shaped member bridging the rung and detachably secured to the hook support member and an elongate angle member positioned adjacent to the rung and between the legs of the U-shaped member.
From the foregoing description, it will be apparent to persons skilled in the art that this invention provides a ladder and a ladder hook attachment which satisfies the foregoing objects.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective showing an aerial cable and ski lift chair, a ladder embodying this invention in position for evacuating a person from the chair and an extra ladder hung on the cable support pole;
FIG. 2 is an enlarged section on the lines 2--2 of FIG. 1;
FIG. 3 is a section on the lines 3--3 of FIG. 2; and
FIG. 4 is a view in side elevation looking in the direction of the arrows 4--4 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, the pole 10 supports the aerial cable 11. The chair 12 is shown in a position from which a person (not shown) may be evacuated from the chair by the use of a ladder embodying this invention. The rungs of the ladder are substantially parallel to the front or forward end of the seat of the chair and substantially normal to the longitudinal centerline of the cable.
The ladder consists of a pair of rigid side rails 14 and a plurality of rigid rungs 15 extending transversely between the side rails. The ladder may be made of metal, wood, fiberglas, or the like.
The elongate hook support member 16, which may be made of aluminum tubing, is rigidly secured to the two uppermost rungs of the ladder.
The lower end of the hook support member 16 is rigidly secured to a rung 15 by a pair of spaced, substantially paralle U-shaped members or bolts 17, the legs of which pass through orifices in a plate 18, orifices in the sides of the hook support member 16 and orifices in the plate 19. The apex of the angle member 20 may be welded to the adjacent face of the plate 18. The rung 15 is positioned between the curved ends of the U-shaped members 17 and the sides of the angle member 20. The angle member may be about 12 inches long and the widths of the sides of the hook support member and the lengths of the plates 18 and 19 may be about 2 inches. The U-shaped members 17 are detachably held in the positions shown in FIGS. 2 and 3 by the nuts 22. The U-shaped members may be made of steel and the plates and angle member may be made of aluminum.
The hook support member 16 is rigidly secured to the upper ladder rung by another pair of spaced, substantially parallel U-shaped members or bolts 24, the legs of which pass through orifices in the sides of the support member and orifices in the plate member 25. They are detachably held in position by the nuts 26. In this case, the periphery of the rung 15 abuts the adjacent side of the support member 16 and the opposite periphery of the rung is positioned against the sides of the angle member 27, the apex of which is positioned against the curved ends of the U-shaped members 24. In this case, the angle member 27 is also about 12 inches long so that it engages the periphery of the rung 15 for a substantial length of the rung.
Use of the plate 18 is unnecessary. In addition, an angle member positioned like the angle member 27 may be used with the U-bolts 17 instead of using the angle member positioned at the opposite side of the rung 15. Furthermore angle members positioned between the peripheries of both rungs and the adjacent side of the hook support member may be used. Other equivalent arrangements will be apparent to persons skilled in the art.
The hook, indicated generally by the numeral 30, may be made of high strength cast aluminum alloy. It is substantially U-shaped in longitudinal section as shown in FIG. 2. The hook shown in the drawings is designed to receive an aerial cable 11 which is about 11/2 inches in diameter. For use with such a cable, the elongate outer end member 30A of the hook may be about 4 inches long and the side members 30B and 30C of the hook may be about 65/8 inches long at the top and converge downwardly to widths of about 21/8 inches when viewed from the side as in FIGS. 3 and 4 of the drawings. The end member 30A and side members 30B and 30C of the hook form a groove 31 which is adapted to receive the cable 11 of the ski chair lift as shown in FIG. 2. The end member 30A is provided with semi-elliptical openings or grooves 30D which receive a portion of the cable when the ladder is tilted to the dot-dash position of FIG. 3.
The lower end of the side member 30B is rigidly secured to the upper end of the hook support member 16 by the bolt 33 which passes through orifices in the support member and the side member 30B of the hook.
It is to be noted that the longitudinal centerline of the groove extends substantially normal to the longitudinal centerlines of the rungs 15 of the ladder when viewed from the top. This causes the rungs of the ladder to be positioned substantially normal to the longitudinal axis of the when viewed from the top cable and substantially parallel to the front or forward end of the seat of the chair to aid in evacuating a person from the chair. It also tends to prevent twisting of the ladder relative to the cable which is important when a person is being evacuated from the chair since frequently the lower ends of the ladder rest upon a frozen or snowy surface. The use of the elongate angle members 20 and 27 also assist in preventing twisting of the hook member relative to the rungs of the ladder.
The latch means, generally indicated by the numeral 40, comprises a generally T-shaped member which includes an arm 41, a hook member 42 and an actuating member 43, The arm 41 is pivotally secured to a lug on the member 30B by a pin 44. The hook member 42 extends through a slot 45 in the side member 30B. A spring 47 has its upper end attached to the side member 30B by a bolt 48 and its lower end attached to the actuating member 43 by the bolt 49. This spring biases or urges the tooth member to its groove closing position shown in FIG. 2 in which the end of the tooth abuts the inner side of the side member 30C.
The rope member 50 is attached to a ring 51 which passes through an orifice near the outer end of the actuating member 43. By pulling on this rope the arm 41 may be moved clockwise (looking at FIG. 2) about the pivotal connection 44 thereby moving the tooth member 42 out of the groove 31 so that the hook may be placed over the cable 11 when the ladder is to be used to evacuate a person from the chair. Upon release of the pulling force on the rope, the spring 47 returns the tooth member to groove closing position where it remains until the ladder is to be removed from the cable.
The ladder may be stored in vertical position when it is not in use by hanging it from a hook (not shown) on the cable support pole 10 as shown in FIG. 1. Since the ladder is in upright position as thus stored, one attendant may effect a rescue without assistance because one of the most difficult tasks of erecting a ladder in a proper position relative to a chair is to place the ladder in an upright position for engaging the hook with the cable.
In use, when it becomes necessary to evacuate a person from a chair of a lift, the attendant removes the ladder from a pole 10 which supports the aerial cable, pulls the cord 50 with the ladder still in vertical position, lowers the ladder to position the cable 11 in the groove 31, releases the cord and adjusts the ladder so that its rungs are substantially parallel to the front of the chair 12. If the person in the chair is able to remove himself from the chair unassisted, the attendant remains at the base of the ladder until the person descends.
If the person in the chair is unable to remove himself from the chair, the attendant ascends the ladder, assists the person from the chair to the ladder, and descends the ladder with the person.
Thereafter, the ladder hook is freed from the cable and the ladder is returned to the hook on the support pole 10 for future use.
From the foregoing description, it will be apparent to persons skilled in the art that this invention has fulfilled all of the objects stated above.
While only one embodiment of the invention has been shown in the drawings it is to be understood that this disclosure is for the purpose of illustration only and that various changes in shape, proportion and arrangements of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.
This invention relates to a ladder for evacuating persons from chair aerial cable lifts.
Chair aerial cable lifts are used extensively in the winter on ski slopes. In use of such lifts, accidents occur making it necessary to evacuate a person from the chair of the lift to prevent injury or loss of life. In one case, a woman failed to properly seat herself on a chair and found herself dangling by one arm from the chair a short distance beyond the loading platform and approximately 25 feet in the air. In another case, a girl, intending to disembark at an intermediate unloading station on a chair lift, found herself suspended by her scarf which had become entangled with the chair. While in each case the lift was stopped, serious problems of evacuating the persons from their predicaments were encountered and, in one case, ended in disaster.
While a common ladder may be erected from the snow-covered surface to the aerial cable so that an attendant may try to ascend it and assist the person to descend the ladder, this is unsatisfactory and dangerous because with the upper end of the ladder resting against the cable, the rungs of the ladder are parallel to the cable and normal to the front opening of the chair. This makes it difficult for the attendant to remove the person from the chair and difficult for the person to remove himself from the chair unassisted. Furthermore, with the legs of the ladder resting upon a slippery, snow-covered surface, the ladder is likely to move while in use either by sliding along the ground or by twisting relative to the cable and the chair.
Usually, there is only one attendant in attendance at the lift loading or unloading area so the ladder used to evacuate the person from the chair should be capable of being erected and used very quickly by a single attendant.
While the following United States patents disclose hooks for holding ladders upon buildings, they would not function satisfactorily for use in evacuating a person from a chair aerial cable lift:
Patent No. Date of Issue Inventor 143,112 Sept. 23, 1873 L.E. Ainsworth 246,658 Sept. 6, 1881 R. Bustin 312,908 Feb. 24, 1885 F. Shickle 526,438 Sept. 5, 1894 M. Croissant 580,454 April 13, 1897 P.J. Gates 1,018,877 Feb. 27, 1912 F.W. Chickering 1,036,482 Aug. 20, 1912 E.A. Fredeen 1,249,855 Dec. 11, 1917 C.R. Taylor 1,252,224 Jan. 1, 1918 W.E. Bittner 2,316,723 April 13, 1943 N.C. Sorenson
In addition to the above patents, U.S. Pat. Nos. 2,963,104 dated Dec. 6, 1960 to Roth and 3,001,603 dated Sept. 26, 1961 to Kraus disclose combined electrical conductor spreaders and ladder hangers but they would not function satisfactorily for use in evacuating a person from a chair aerial cable lift.
One object of this invention is to provide a novel ladder for evacuating a person from chair aerial cable lifts.
Another object is to provide such a ladder which may be erected to an aerial cable adjacent to the chair quickly by a single attendant.
A further object is to provide such a ladder which, when erected, presents the rungs of the ladder substantially parallel to the front or forward end of the seat of the chair to facilitate evacuating a person from the chair.
A still further object is to provide such a ladder which does not twist relative to the cable or the ground after it has been erected.
Another object is to provide such a ladder with a hook which permits variation of the angle of the ladder relative to the cable without loss of torsional support.
A further object is to provide such a ladder which includes a novel and efficient safety latch for use in fast erection of the ladder and in retaining the ladder in erected position during evacuation of a person from a chair lift.
Yet another object is to provide such a ladder with novel and efficient means for detachably and firmly securing a member which supports the hook to one or more rungs of a ladder so that the hook does not twist or turn relative to the ladder in use.
A still further object is to provide a novel ladder hook attachment for use with a ladder for evacuating persons from chair or other aerial cable lifts.
Another object is to provide such a ladder hook attachment which is durable, economical to manufacture and easy to install upon any rigid ladder.
Other objects and advantages will be apparent to persons skilled in the art from the following description.
In its broadest aspect, the invention comprises a ladder having a pair of rigid side rails, a plurality of spaced rigid rungs extending transversely between said side rails, means for rigidly securing the lower end of the hook support member to at least one ladder rung, and a hook which is substantially U-shaped in cross section rigidly attached to the upper end of the support member, the hook comprising an elongate outer end member and two spaced side members which combine to form a groove adapted to receive the cable of an aerial lift, the longitudinal centerline of the groove extending substantially normal to the longitudinal centerlines of the rungs of the ladder when viewed from the top. Consequently when the bottom of the groove is positioned upon the cable of an aerial lift the rungs of the ladder are positioned substantially normal to the longitudinal centerline of the aerial cable when viewed from the top and substantially parallel to the forward end of the seat of a chair suspended from the aerial cable.
In a preferred embodiment, the elongate outer end member comprises a pair of semi-elliptical grooves, one at each end thereof.
In another preferred embodiment, the sides of the spaced side members converge as they extend downwardly from the elongate outer end member.
Preferably the hook also comprises latch means for releasably opening and closing the groove at a locality spaced below the elongate outer end member of the hook. This latch means may comprise an arm, one end of which is pivotally attached to one side member of the hook, a tooth member attached to the other end of the arm and normally extending transversely of the groove to close it and an actuating member attached to the other end of the arm and extending in the opposite direction from the tooth member. Spring means is provided which has one end attached to the actuating member and the other end attached to one side member of the hook and this spring means normally biases the tooth member to groove closing position. A rope is attached to the actuating member for moving the arm about its pivotal connection to the side member, whereby the tooth member may be moved from groove closing position to open position to permit the hook to be quickly positioned about an aerial cable.
Preferably the means for securing the hook support member to a ladder rung comprises at least one U-shaped member bridging the rung and detachably secured to the hook support member and an elongate angle member positioned adjacent to the rung and between the legs of the U-shaped member.
From the foregoing description, it will be apparent to persons skilled in the art that this invention provides a ladder and a ladder hook attachment which satisfies the foregoing objects.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective showing an aerial cable and ski lift chair, a ladder embodying this invention in position for evacuating a person from the chair and an extra ladder hung on the cable support pole;
FIG. 2 is an enlarged section on the lines 2--2 of FIG. 1;
FIG. 3 is a section on the lines 3--3 of FIG. 2; and
FIG. 4 is a view in side elevation looking in the direction of the arrows 4--4 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, the pole 10 supports the aerial cable 11. The chair 12 is shown in a position from which a person (not shown) may be evacuated from the chair by the use of a ladder embodying this invention. The rungs of the ladder are substantially parallel to the front or forward end of the seat of the chair and substantially normal to the longitudinal centerline of the cable.
The ladder consists of a pair of rigid side rails 14 and a plurality of rigid rungs 15 extending transversely between the side rails. The ladder may be made of metal, wood, fiberglas, or the like.
The elongate hook support member 16, which may be made of aluminum tubing, is rigidly secured to the two uppermost rungs of the ladder.
The lower end of the hook support member 16 is rigidly secured to a rung 15 by a pair of spaced, substantially paralle U-shaped members or bolts 17, the legs of which pass through orifices in a plate 18, orifices in the sides of the hook support member 16 and orifices in the plate 19. The apex of the angle member 20 may be welded to the adjacent face of the plate 18. The rung 15 is positioned between the curved ends of the U-shaped members 17 and the sides of the angle member 20. The angle member may be about 12 inches long and the widths of the sides of the hook support member and the lengths of the plates 18 and 19 may be about 2 inches. The U-shaped members 17 are detachably held in the positions shown in FIGS. 2 and 3 by the nuts 22. The U-shaped members may be made of steel and the plates and angle member may be made of aluminum.
The hook support member 16 is rigidly secured to the upper ladder rung by another pair of spaced, substantially parallel U-shaped members or bolts 24, the legs of which pass through orifices in the sides of the support member and orifices in the plate member 25. They are detachably held in position by the nuts 26. In this case, the periphery of the rung 15 abuts the adjacent side of the support member 16 and the opposite periphery of the rung is positioned against the sides of the angle member 27, the apex of which is positioned against the curved ends of the U-shaped members 24. In this case, the angle member 27 is also about 12 inches long so that it engages the periphery of the rung 15 for a substantial length of the rung.
Use of the plate 18 is unnecessary. In addition, an angle member positioned like the angle member 27 may be used with the U-bolts 17 instead of using the angle member positioned at the opposite side of the rung 15. Furthermore angle members positioned between the peripheries of both rungs and the adjacent side of the hook support member may be used. Other equivalent arrangements will be apparent to persons skilled in the art.
The hook, indicated generally by the numeral 30, may be made of high strength cast aluminum alloy. It is substantially U-shaped in longitudinal section as shown in FIG. 2. The hook shown in the drawings is designed to receive an aerial cable 11 which is about 11/2 inches in diameter. For use with such a cable, the elongate outer end member 30A of the hook may be about 4 inches long and the side members 30B and 30C of the hook may be about 65/8 inches long at the top and converge downwardly to widths of about 21/8 inches when viewed from the side as in FIGS. 3 and 4 of the drawings. The end member 30A and side members 30B and 30C of the hook form a groove 31 which is adapted to receive the cable 11 of the ski chair lift as shown in FIG. 2. The end member 30A is provided with semi-elliptical openings or grooves 30D which receive a portion of the cable when the ladder is tilted to the dot-dash position of FIG. 3.
The lower end of the side member 30B is rigidly secured to the upper end of the hook support member 16 by the bolt 33 which passes through orifices in the support member and the side member 30B of the hook.
It is to be noted that the longitudinal centerline of the groove extends substantially normal to the longitudinal centerlines of the rungs 15 of the ladder when viewed from the top. This causes the rungs of the ladder to be positioned substantially normal to the longitudinal axis of the when viewed from the top cable and substantially parallel to the front or forward end of the seat of the chair to aid in evacuating a person from the chair. It also tends to prevent twisting of the ladder relative to the cable which is important when a person is being evacuated from the chair since frequently the lower ends of the ladder rest upon a frozen or snowy surface. The use of the elongate angle members 20 and 27 also assist in preventing twisting of the hook member relative to the rungs of the ladder.
The latch means, generally indicated by the numeral 40, comprises a generally T-shaped member which includes an arm 41, a hook member 42 and an actuating member 43, The arm 41 is pivotally secured to a lug on the member 30B by a pin 44. The hook member 42 extends through a slot 45 in the side member 30B. A spring 47 has its upper end attached to the side member 30B by a bolt 48 and its lower end attached to the actuating member 43 by the bolt 49. This spring biases or urges the tooth member to its groove closing position shown in FIG. 2 in which the end of the tooth abuts the inner side of the side member 30C.
The rope member 50 is attached to a ring 51 which passes through an orifice near the outer end of the actuating member 43. By pulling on this rope the arm 41 may be moved clockwise (looking at FIG. 2) about the pivotal connection 44 thereby moving the tooth member 42 out of the groove 31 so that the hook may be placed over the cable 11 when the ladder is to be used to evacuate a person from the chair. Upon release of the pulling force on the rope, the spring 47 returns the tooth member to groove closing position where it remains until the ladder is to be removed from the cable.
The ladder may be stored in vertical position when it is not in use by hanging it from a hook (not shown) on the cable support pole 10 as shown in FIG. 1. Since the ladder is in upright position as thus stored, one attendant may effect a rescue without assistance because one of the most difficult tasks of erecting a ladder in a proper position relative to a chair is to place the ladder in an upright position for engaging the hook with the cable.
In use, when it becomes necessary to evacuate a person from a chair of a lift, the attendant removes the ladder from a pole 10 which supports the aerial cable, pulls the cord 50 with the ladder still in vertical position, lowers the ladder to position the cable 11 in the groove 31, releases the cord and adjusts the ladder so that its rungs are substantially parallel to the front of the chair 12. If the person in the chair is able to remove himself from the chair unassisted, the attendant remains at the base of the ladder until the person descends.
If the person in the chair is unable to remove himself from the chair, the attendant ascends the ladder, assists the person from the chair to the ladder, and descends the ladder with the person.
Thereafter, the ladder hook is freed from the cable and the ladder is returned to the hook on the support pole 10 for future use.
From the foregoing description, it will be apparent to persons skilled in the art that this invention has fulfilled all of the objects stated above.
While only one embodiment of the invention has been shown in the drawings it is to be understood that this disclosure is for the purpose of illustration only and that various changes in shape, proportion and arrangements of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.