US2469071A - Ladder construction - Google Patents

Description

May 3, 1949. J. KYDD LADDER CONSTRUCTION 2 Sheets-Sheet 1 Filed Feb. 16, 1944 INVENTOR JAM/56 K m) ATTORNEY May 3, 1949. .1. KYDD 2,469,071

LADDER CONSTRUCTION Filed Feb. 16, 1944 2 Sheets-Sheet 2 INVENTOR JAM/IS Avpp 7*. ATTORNEY Patented May 3, 1949 UNITED STATES PATENT OFFICE LADDER CONSTRUCTION James Kydd, Ozone Park, N. Y., assignor to Metropolitan Device Corporation, Brooklyn, N. Y., a corporation of New York Application February 16, 1944', Serial No. 522,541

2 Claims. 1

The: invention herein disclosed relates to a portable ladder construction of a kind that is especially suitable for servicing overhead equipment in factories.

In servicing overhead equipment. in factories, it. is. diflicult: and in some cases impossible. to use an ordinary ladder- Many factories are constructed with unusually high ceilings and often without any protuberances against which the upper edge of a ladder may be steadied. In additionmachines and other equipment. are often arranged in rows forming narrow aisles while much of" the overhead equipment. such as electric lights, for example, are directly over the machines.

An object at this invention is to provide a portable ladder construction which is entirely supported at thev base and which is serviceable when extended. at an angle to the vertical. Another object of the invention is to provide a ladder of. this kind that is readily and easily moved from place to; place and then manipulated by a single person. Another object of the invention is to provide av ladder of this kind which may be readily and easily secured in any location or position.

The foregoing objects and certain advantages that will. hereinafter appear are realized in the embodiment of the invention illustrated in the accompanying drawings and described in detail below.

The drawings include Fig. 1 which is a side elevation of a portable ladder embodying the invention;

Fig. 2 which is an end elevation of the. ladder support with the ladder in elevation;

Fig. 3 which is a fragmentary end elevation of thelower end of the ladder;

Fig. 4 which is a sectional side elevation of the same;

Fig. 5 which is an enlarged, fragmentary elevation of a hand truck and illustrates the floor lock. for the. ladder;

Fig. 6 which is an isometric View of the end of the extension section of the ladder and one form oftool'box thereon; and

Fig. 7 is a similar view with a modified form of tool box;

The particular ladderillustrated in the drawings is'mounted' upon an industrial truck, preferably a hand truck I. This hand truck is of a kind well known and in common use. It includes a platform supported on two sets of wheels 3' and: 4. Each. of the? wheels 4 is journaled on a shait 5 secured in a fixed bracket. 1: secured to the platform. The wheels 3 are mounted. in caster brackets 8 which are rotatable about vertical axes. At one end of the truck there are spaced corner posts 9- between which a rail it extends. While a hand truck. is. shown, like portable platforms may be used such as are now used in industries.

The truck is provided with a. pair of. floor locks: which serve, when the ladder is inuse, to steadythe truck and prevent accidental movement thereof. There is one of these floor locks mounted at each of the posts. 9, one of. which is shown in detail in Fig. 5. The particular floor loch illustrated includes a tubular metal member H which is secured to the post 9. At one end of the tubular member, there is an outwardly extending flange l2 that engages the undersideof the. platform 2.. A rod 13: is slidable in and extends through: the member H. At its moper end, the rod is bent to formv a handle.- 14;. and. to the lower end of the: rod, there is secured: a. floor-engaging shoe i5. Between flange i i anda collar l6, secured onv the rod hijust above the shoe I5, there is a spring H: which acts. to: press the shoe ['5' against the floor. When it" is desired to move the truck, the rod I3. is lifted: manually against the action of the spring H. A catch bracket i8. is provided on the post 9 for engaging the handle M and holding the shoe It. out of contact with the floor. The handle is first elevated and then rotated to engage the. catch: bracket. Screw operated floor locks may. of course, be used.

On the platform 2, there is. a. ladder base I18. This is a very heavy base preferably made up of scrap steel: embedded in cement to give: the base great. weight. A pivot: rod: 20': extends from the platform 2 to which it is: secured. through. the base l9 and a rotatable spider 2.1-, rotatable about the rod 2!] and on a plate 22 secured on. the base. On this rotatable spider; which may desirably consist. of a single casting having; our radial arms, the: frame for supporting the ladder is mounted... This; frame consists. of. two. spaced. vertical, parallel: channel; irons 23 811131? two chan. nel irons 24: inclined: to: the horizontal. Each of the. vertical channel irons; is secured. at one end to the rotatable spider and extendssubstantially perpendicularly from the. plane: thereof. Each inclined. channel iron 24" is secured at one end to the horizontal spider and. at the other end to the upper end of the vertical chemist iron 23;. These channel. irons; iorm a pair of spaced. rigid, triangular uprights between. which.

' the ladder is pivotallwmountedi.

The ladder illustrated is of the adjustable, extension type having two sections 25 and 26, the section 26 being slidable on the section 25 in the usual manner. The lower section 25 of the ladder is mounted on a pivot 21 extending through the side rails 28 and 29 of the section 25 and through the frame uprights at the point where the elements 23 and 24 are joined together.

At the lower end of the section 25 of the ladder, there are mounted counterweights 36 and 3|, one secured to the lower end of each of the side rails 28 and 29. In the counterweight 36, there is slidably mounted a pin 32 that extends perpendicularly to the plane of the side rail 26. A similar pin 33 is slidably mounted in the counterweight 3|. These pins cooperate with angularly disposed, spaced frame members 34 and 35 that are secured to the rotatable spider. The lower end of the ladder swings between these two frame elements. Each of the frame elements 34 and 35 has a series of openings 34a, 35a therethrough disposed in an arc concentric with the axis about which the ladder pivots. The holes 35a, 35a. through the frame elements are of a diameter to receive the pins 32 and 33 respectively. When the pins extend into aligned openings in the frame elements 34 and 35, the ladder is positioned in one of several angular positions and is secured in that position by the interengagement of the pins and the frame elements.

The pins 32 and 33 are spring-pressed in opposite directions so that each pin is urged in a direction to enter the openings in the frame elements 34 and 35. For this purpose, there is provided a cylindrical element or sleeve 36 that extends between and that is rigidly fastened to the counterweights. The pins 32 and 33 extend into the cylindrical element 36. A spring 31 within the element 36 presses on the ends of the pins within the sleeve 36. Tubular sleeves 31 and 38 are slidably mounted on the element 36. A pin 39 extends from the pin 32 and through a diametrical, longitudinal slot in the element 36 and through the sleeve 31', and a pin 46 extends from the pin 33, a slot provided therefor in the element 36 and into the sleeve 38. The slots in the element 36 through which the pins 39 and 46 extend are of sufficient length to permit the pins 32 and 33 to be moved toward each other a distance to disengage them from the openings in the frame elements 34 and 35, the sleeves 31' and 38 forming hand-grips for this purpose. The pins 39 and 43 also limit, by abutment with the ends of the slots, the outward movement of the pins 32 and 33.

From the description of this construction, it will be seen that when it is desired to position the ladder the operator grasps the sleeves 31 and 38 and draws them inwardly until the pins 32 and 33 are free of any openings in the frame elements 34 and 35. With these pins thus retracted, the ladder is moved about its pivotal connection to the desired position when the pins are released and the ladder moved slightly until the bolts, by virtue of the action of the spring, move into the desired pair of openings through the frame elements 34 and 35. The ladder is thus positioned and secured in position.

When the ladder is raised and the extension section 26 is extended, there is a considerable force exerted at the counterweights, a force that is somewhat greater than that which can be resisted by one individual. Thus, if the pins 32 and- 33 are withdrawn in an attempt to lower the ladder to the position shown in-Fig. 1, while the extension section is extended, the ladder will drop. This may result in injury to the operator, the ladder or both. To prevent this a safety lock is provided such that it is impossible to withdraw both pins 32 and 33 while the extension section is raised or extended.

The safety lock is arranged to engage the pin 39 when the extension section 26 is raised. For this purpose, the pin 39 extends beyond the sleeve 31. The safety lock is mounted in a stationary bracket 4| mounted on the counterweight 36. A pair of rods 42 and 43 are slidably mounted in the bracket 4|. At one end, the rods 42 and 43 are secured to a plate 44 which extends into the path of an angle iron 45 on the extension section 26. The other end of the rods are secured to a catch 46 which consists of an angle iron having a flange 41 with a notch 48 therein. Springs 49, acting between the plate 44 and the bracket 4| resiliently urge the rods 32 and 43 upwardly in which position the pin 39 is received in the notch 48 of the catch 56. In this position, the pin 32 cannot be withdrawn.

When the extension section 26 is raised, the

. catch 46 automatically moves into position to engage the pin 39. When the extension section is lowered, the angle iron 45 engages the plate 44 and moves the catch 46 to the position illustrated in which position the pin 39 is released. Thus, as the operator requires both hands to release both pins 32 and 33, the ladder cannot be released unless the extension section is lowered. A chain 56 serves to hold the ladder in a horizontal position when it is not in use.

In Fig. 6 there is illustrated a tool box 5| mounted upon the end of the extension section 26, spaced therefrom and arranged to remain horizontal irrespective of the position of the ladder. For the purpose of mounting the tool box 5|, brackets 52 and 53 are carried by the rails of the section 26. A pair of converging links 54 and 55 extend from and are secured to the bracket 52. A like pair of converging links 56 and 5'! extend from the bracket 53. The box 5| is pivotally secured to these converging links at their apex.

A stiffening rod 58 extends between the brackets 52 and 53.

With some ladders of the type described, it is desirable to have provision at the top of the extension section for raising loads greater than a man can carry up the ladder. For this purpose, a special tool box is provided at the top so constructed that loads of approximately five hundred pounds may be elevated by means of a chain block supported by the tool box. This tool box performs two functions. It not only provides the support for the chain block but also acts as a box girder to resist the collapsing force at the end of the ladder due to the weight suspended from the chain block.

Such a tool box construction is illustrated in Fig. '7. Here a tool box 59 is pivotally supported between, and at the ends of, brackets 66 and 6| extending from the side rails substantially perpendicularly to the plane of the section 26. A rod 62 extends between the brackets inwardly of the tool box. On the bottom of the tool box there is an eye 63 for a chain block.

It will be obvious that various changes may be made by those skilled in the art in the details of the embodiment of the ladder construction illustratedinthe drawings and described in detail above within the principle and scope of the inven: tion as expressed in the appended claims.

I claim:

1. In a portable ladder construction of the kind described, the combination comprising a frame, a ladder having side rails and rungs pivotally mounted in the frame, the ladder including an extension section, means carried by the frame and the ladder for securing the ladder in various angular positions, and means actuated upon movement of the extension section to extended position for locking said securing means.

2. In a portable ladder construction of the kind described, the combination comprising a frame, a ladder having side rails and rungs pivotally mounted in the frame, the ladder including an extension section, means carried by the frame and ladder for securing the ladder in various angular positions, interengaging means for locking said securing means when the extension section is in extended position, and. means engageable by said extension section in its lower position for releasing said interengaging means.

JAMES KYDD.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 523,709 Leach July 31, 1894 666,099 Kepler Jan. 15, 1901 878,863 Brazil] Feb. 11, 1908 1,135,799 Hogan Apr. 13, 1915 1,482,117 Cowles Jan. 29, 1924 1,605,291 Schmidt Nov. 2, 1926 1,926,696 Murphy Sept. 12, 1933 2,229,987 Phelps Jan. 28, 1941 2,248,794 Troche July 8, 1941 2,310,119 Reinhardt Feb. 2, 1943 2,362,170 Swaisgood Nov. 7, 1944 2,370,661 Hayes Mar. 6, 1945 FOREIGN PATENTS Number Country Date 153,421 Switzerland June 1, 1932

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