US3208555A

US3208555A - Hoisting attachment for a ladder

Info

Publication number: US3208555A
Application number: US368639A
Authority: US
Inventors: Fred C Fry
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-05-19
Filing date: 1964-05-19
Publication date: 1965-09-28
Anticipated expiration: 1982-09-28

Description

F. c. FRY 3,208,555

Sept.28, 1965 HOISTING ATTACHMENT FOR A LADDER 3 Sheets-Sheet 1 Filed May 19, 1964 HIHIIIM.

Sept. 28, 1965 F. c. FRY

HOISTING ATTACHMENT FOR A LADDER 5 Sheets-Sheet 2 Filed May 19, 1964 law-"'- A Sept. 28, 1965 c, FRY

HOISTING ATTACHMENT FOR A LADDER I5 Sheets-Sheet 3 Filed May 19, 1964 United States Patent 3,208,555 HOISTING ATTACHMENT FOR A LADDER Fred C. Fry, Dial Court, Normal, Ill. Filed May 19, 1964, Ser. No. 368,639 7 Claims. (Cl. 182-116) This invention relates to an apparatus for lifting and supporting objects such as building panels, scaffolding, etc. and the primary object is to provide such an apparatus which is constructed in a novel manner so that it can be easily attached to and removed from a conventional stepladder.

Another object of this invention is to provide a hoisting apparatus for mounting on a stepladder which transfers the weight of the supported object to the stepladder in such a manner as to obtain maximum stability.

Another object is to provide a hoisting attachment for a stepladder which can be folded while attached to the ladder for compactness and ease of storage.

Another object of this invention is to provide a hoisting apparatus which is readily portable.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a perspective View of hoisting apparatus embodying the novel features of the present invention, two units being shown as mounted on stepladders and supporting a building panel;

FIGURE 2 is a fragmentary front elevational view of the apparatus mounted on a stepladder;

FIGURE 3 is a fragmentary side elevational view of the apparatus mounted on a stepladder;

FIGURE 4 is a side elevational view of the stepladder and hoisting apparatus in the folded condition;

FIGURE 5 is a plan view of the hoisting apparatus and stepladder as shown in FIG. 4;

FIGURE 6 is a sectional View taken along line 6-6 of FIG. 3; and

FIGURE 7 is a sectional view taken along line 77 of FIG. 4.

FIG. 8 is a fragmentary sectional view taken along the line 8--8 of FIG. 7;

FIG. 9 is a sectional view taken along the line 99 of FIG. 6;

FIG. 10 is a fragmentary end elevational view of the cable drum support looking to the right from the left in FIG. 2;

FIG. 11 is a fragmentary sectional view taken along along the line 11-11 of FIG. 12; and

FIG. 12 is a fragmentary sectional view taken along the line 12-12 of FIG. 10.

The hoisting apparatus 10 shown in the drawings to illustrate the present invention is intended to be used when mounted on a stepladder 11. A single hoisting apparatus and a stepladder can be used or, as shown in FIGURE 1, a pair of stepladders each equipped with this apparatus can be used to lift and support an object such as a fiat rectangular building panel 12 in a horizontal position. In general, the apparatus comprises a supporting framework 13 which rests on a stepladder, an elevating structure 14 which is guided by the supporting framework and an elevating mechanism 15 mounted on the supporting framework and connected to the elevating structure to raise, lower and hold it in various elevated positions.

In accordance with the present invention, the hoisting apparatus 10 is constructed in a novel manner so as to permit its rapid attachment to and removal from a ladder 11 while providing an apparatus which cannot easily be dislodged from the ladder. To accomplish this purpose, the supporting framework 13 is formed of a flat rectangular top plate 16 which is positioned on the top step 17 of the ladder and extends outwardly beyond the ends of the top step. To hold the top plate on the top step of the ladder and to provide a support for the elevating mechanism 15, the framework includes a brace portion 18 which is attached to and depends from the top plate at the same angle as the front legs 11a of the ladder intersect the top step of the ladder when the ladder is unfolded. Thus, the brace portion of the framework will lean against and engage the front legs of the ladder when the top plate is positioned on the top step of the ladder. The bracing portion of the framework consists of four flat metal bars 19 of inverted L-shape with shorter legs which are fastened as by screws (not shown) to the bottom surface of the top plate and with longer legs extending downwardly and outwardly to lie along the outer sides of the front legs of the stepladder. A pair of lateral bars 20 extend across and are fastened to the downwardly extending bars to form a rigid structure. One bar 20 is fastened to lower ends of all four longer legs, but shorter upper bar 20 only spans inner legs. An angle iron is used as the lower bar for a purpose to be disclosed later. These lateral bars will extend across and rest against the front legs of the stepladder when the framework is in position.

To provide maximum stability when the hoisting apparatus is mounted on a stepladder, the elevating structure 14 is arranged so that it moves in a vertical plane which passes through the top step 17 of the ladder and substantially bisects the angle formed by the front legs 11a and rear legs 11b of the ladder. Also, due to the construction of the hoisting apparatus, the weight of the supported object 12 is transferred to the top plate 16 of the supporting framework 13 and then to the top step of the ladder and distributed over this step in a substantially uniform manner. In order to perform in this way, the elevating structure is constructed of a flat rectangular platform 21 which supports the object being elevated and which in turn is supported and moved by a pair of spaced poles 22. The elevating structure is completed by a bar 23 which connects the bottoms of the poles to form a rectangular frame. The poles extend through and are guided within openings 24 in the top plate of the supporting structure, these openings being located outwardly beyond the ends of the top step 17 of the ladder. The poles are thereby positioned so as to straddle the ladder in a plane extending through the top step of the ladder and substantially bisecting the angle formed by the front and rear legs of the ladder.

To guide the poles 22 and restrict their movement to a vertical plane extending through the top step 17 of the stepladder, guiding surfaces are provided at and below the .top plate 16 of the framework 13. In this instance, the guides at the top plate are provided by washers 24a which are fastened to the upper surface of the top plate concentrically with the openings 24 in this plate. The washers have interior openings of the same diameter as the exterior of the poles 22 in order to provide guiding surfaces for the .poles.

The lower guiding surfaces for the poles 22 are provided by the interior surfaces of tubular sleeves 25 which receive the poles and are positioned beneath the openings in the top plate. The sleeves are supported by the ends of a U-shaped member 26 which extends around the front legs 11a of the ladder and rests on the ladder below the framework 13. The bight portion 27 of this U-shaped member extends across and engages the front legs of the ladder. To hold the U-shaiped support in position on the ladder, J-shaped hooks 28, which extend through openings 28a in the bight portion, are hooked around the rear edge of a step 29 and held against .the bight portion by wing nuts 28b. To prevent bowing of the bight portion when the wing nuts are drawn up tightly, a tab 27a is positioned in the center of the bight and extends downwardly therefrom to engage the front edge of the step.

The mechanism for raising and lowering the elevating structure 14 comprises cables 30 which are attached in a suitable manner to the bottom cross bar 23 connecting the poles 22, extend through pulleys 31 attached to the bottom of the top plate 16 of the supporting framework 13 and are wound around a drum 32 of a Winch. The winch drum is jou'rnaled in bearings 33 supported on the bracing portion 18 of the supporting framework and is turned by a handle 34 attached to one end of the drum. In the embodiment shown in the drawings, the bearings are supported by uprights 33a aflixed, as by welding, to the lower lateral bar which, as previously described, is formed from an angle iron. The rotation of the drum is controlled by a ratchet and pawl mechanism 36 at one end of the drum. This mechanism fits in one of the bearings 33 and is selectively adjustable by a movement of an indicator 36a to permit rotation of the drum in either direction for winding and unwinding the cables as well as to hold the elevating structure in various elevated positions.

In the present instance, the pawl and ratchet mechanism 36 is of the type commonly used on socket wrenches. Such mechanism is shown in FIGS. 10 to 12 and includes a toothed ratchet wheel 38 rotatably mounted in a casing which constitutes one of the bearings 33. A square cross section male projection 39 projecting rigidly from the wheel fits into a socket 40 of similar shape in the drum 32 (FIG. 12). The indicator 36a projects rigidly from a shaft 41 journaled in the upright 33a and connected by a pin 42 to a pawl 43 for shifting the pawl to different positions for rotation of the wheel and drum. in opposite directions in a well-known manner in response to shifting of the indicator 36a to its different limit positions shown in full and in phantom in FIG. 10.

The pulleys 31 supporting the cables are attached to the top plate 16 outwardly beyond the ends of the top step 17 of the ladder so that the weight of the elevating structure and the supported object is transferred to the top plate of the supporting framework and the top step of the ladder. This arrangement provides stability since the weight carried by the ladder is concentrated in a plane between the front and rear legs.

The previously mentioned guides for the elevating framework 14 are constructed and supported in a novel manner to permit the poles 22 of the elevating framework to be moved into parallelism with the bracing portion 18 of the supporting framework so that the ladder and hoisting apparatus can be folded compactly, as shown in FIGURE 4, for ease of storage. In order to permit the hoisting apparatus to be folded, it is necessary that the poles be tiltable relative to the top plate 16 and toward the bracing portion. This is accomplished by forming the openings 24 in the top plate with increasing cross section from the surface of the top plate adjacent the washer 24a, which in this instance is the top surface, to the opposite surface and by supporting the sleeves 25 so that they can be moved from an operating position where they are located directly below the openings 24 to a folded position where they are located adjacent to the front legs 11a. The shape of the openings and the use of washers as guiding surfaces at the top of the poles permits the poles to be tilted relative to the top plate when the sleeves are moved to the folded position yet restricts the movement of the poles to the vertical when the sleeves are placed in the operating position.

To enable the sleeves 25 to be movable between the aforementioned positions, the arms of the U-shaped guide support 26 are divided into sections 35a and 35b which are pivotally connected to each other and to the sleeves. Sections 35a are formed as short stubs which are rigidly connected to and extend outwardly from the ends of bight portion 27 of the U-shaped support. These stubs are connected by pivot pins 35c to the ends of arm sections 35b which are at their opposite ends connected to the sleeves by pivot pins 35d. The pivotal connections 350 at .the stub end of the arm sections 35b permit these sections to be folded into parallelism with the front legs of the stepladder and thus allow the sleeves to be moved adjacent to the front legs. The pivotal connections 35d between the arm sections and the sleeves allow the sleeves to remain aligned with the poles as the sleeves are moved between their operating and folded positions.

The hoisting apparatus 10 can be most readily mounted on a stepladder 11 when the stepladder is folded as shown in FIG. 4 and is lying fiat with the front legs 11a and steps 29 facing upward. The elevating structure 14 of the hoisting mechanism is moved to its lowered position so that the platform 21 contacts the top plate 16 of the supporting framework 13 and the U-shaped member 26 supporting the lower guides 25 is folded to allow the poles 22 to be parallel with the brace portion 18 of the supporting framework. With the hoisting apparatus thus compacted, it is ready to be placed on the stepladder. Since the stepladder generally is longer than the poles of the hoisting apparatus, the bar 23 connecting the bottoms of the poles must be slipped over the bottoms of the legs of the ladder and between the front and rear sets of legs of the ladder. When the bar is so positioned, the top plate of the supporting framework is moved into position to contact the top step of the ladder with the bracing portion of the framework resting against the front legs of the ladder as shown in FIG. 4. The supporting framework can be permanently attached to the ladder by means of suitable fasteners (not shown) to secure the top plate to the top step of the ladder. However, the use of fasteners is not necessary since the supporting framework will be held in position on the ladder by its own weight when the ladder is in its upright operating position. The J-shaped hooks 28 which extend through openings 28a in the bight portion 27 of the U-shaped support and are held therein by wing nuts 28b, are hooked around the rear edge of a step 29 and are drawn up by the wing nuts until the tab 27a is tightly engaged with the front edge of said step. The correct step to be used is preselected and is determined by the length of the arms 35 of the U-shaped support and the angle formed by the front legs of the ladder with the vertical so that the sleeves will be positioned beneath the openings in the top plate when the ladder is unfolded.

The ladder and hoisting apparatus are now ready to be put in use by unfolding the ladder and placing it in its upright position with the legs on a supporting surface. When the ladder is upright, the poles 22 are moved away from the front legs 11a and into their vertical position between the front and rear legs of the ladder. Movement of the legs will automatically unfold the arms 35 of the U-shaped support 26 and position the sleeves 25 beneath the openings 28 in the top plate so that the poles can be guided by the sleeves and the washers 24a for movement in a vertical plane extending through the top step of the ladder. The elevating structure can now be raised by setting the ratchet indicator 36a in the lifting position and by turning the handle 34 in the proper direction.

I claim:

1. A hoisting apparatus for installation on a stepladder, said apparatus having, in combination, a supporting framework having an elongated fiat top plate resting on the top step of said stepladder and extending beyond the ends thereof and a bracing portion attached to said top plate and extending angularly and downwardly from one side of the top plate to lie against said stepladder when the top plate is positioned on the top step thereof, openings located in said plate outwardly beyond the ends of said top step, poles slidably mounted in said openings for guided vertical movement therein, a platform mounted on the tops of said poles, elevating means mounted on said framework and connected to said poles to raise the poles and platform relative to said framework, releasable means to hold the poles and platform when elevated, and additional guiding means engaging said poles below said openings.

2. A hoisting apparatus of the type called for in claim 1 in which the elevating means comprises cables attached to the poles and supported by pulleys attached to said flat plate, a drum journaled on said bracing portion of the framework for receiving and winding said cables, and handle means attached to said drum to turn the drum, said releasable means having a ratchet and pawl to prevent unwinding of the cables from the drum.

3. A hoisting apparatus of the type called for in claim 1 in which washers having giuding surfaces for the poles are attached to one surface of said top plate and said openings are formed with increasing cross section from the surface of the top plate adjacent said washers to the opposite surface to allow the poles to be tilted relative to the top plate.

4. A hoisting apparatus of the type called for in claim 1 in which said additioinal guiding means comprises a pair of tubular sleeves connected to the ends of the arms of a U-shaped member having a bight portion adapted to clamp around and be supported by the legs of the stepladder, said arms being pivotally attached to said bight portion and to said sleeves to permit the sleeves to be moved from under said openings and adjacent to said legs of the ladder.

5. A hoisting apparatus for installation on a stepladder, said apparatus comprising a supporting framework resting on the top step of the stepladder, an elevating structure having vertical members positioned outwardly of the ends of said top step and guided by said framework for vertical movement in a plane extending through the top step of the stepladder, elevating means connected to said framework and elevating structure for controlling the vertical movement of the elevating structure relative to the framework and for transferring the weight of said elevating structure to the top step of said ladder, and selectively releasable means to hold the elevating structure in position relative to said framework.

6. A hoisting apparatus for installation on a stepladder, said apparatus having a framework supported by the top step and a pair of legs of said stepladder, an elevating structure having a top platform mounted on a pair of poles spaced apart a distance greater than the length of said top step, guides attached to said framework and positioned outwardly of the ends of the top step to receive said poles and control their movement in a vertical plane extending through said top step, said poles being inserted in said guides with said top platform positioned above said framework, a rotatable drum journaled on said framework, a handle attached to the drum for causing rotation thereof, cables attached to the elevating structure and engageable with the drum to wind about the drum and lift said structure upon rotation in one direction and to unwind and lower the structure upon rotation in the opposite direction, and releasable means to prevent rotation of the drum in said opposite direction.

7. A hoisting apparatus for installation on a stepladder, said apparatus comprising a supporting framework resting on the stepladder, a rectangular elevating framework guided by said supporting framework for vertical move ment in a plane extending through the top step of the stepladder, said elevating framework having vertical members spaced outwardly from said top step and horizontal members connected to said vertical members and positioned above and below the top step, elevating means mounted on said supporting framework and connected to said rectangular framework for controlling the vertical movement of said rectangular framework relative to the supporting framework and for transferring the weight of said elevating framework to the top step of said ladder, and selectively releasable means for holding the rectangular framework in elevated positions relative to said supporting framework.

References Cited by the Examiner UNITED STATES PATENTS 656,946 8/00 Corduan 182-129 X 2,237,543 4/41 Berchem 182l49 3,089,599 5/63 Casella 182-429 X 3,131,928 5/64 Whipple 182129 X HARRISON R. MOSELEY, Primary Examiner.

REINALDO P. MACHADO, Examiner.

Claims

5. A HOISTING APPARATUS FOR INSTALLATION ON A STEPLADDER, SAID APPARATUS COMPRISING A SUPPORTING FRAMEWORK RESTING ON THE TOP STEP OF THE STEPLADDER, AN ELEVATING STRUCTURE HAVING VERTICALK MEMBERS POSITIONED OUTWARDLY OF THE ENDS OF SAID TOP STEP AND GUIDED BY SAID FRAMEWORK FOR VERTICAL MOVEMENT IN A PLANE EXTENDING THROUGH THE TOP STEP OF THE STEPLADDER, ELEVATING MEANS CONNECTED TO SAID FRAMEWORK AND ELEVATING STRUCTURE FOR CONTROLLING THE VERTICAL MOVEMENT OF THE ELEVATING STRUCTURE RELATIVE TO THE FRAMEWORK AND FOR TRANSFERRING THE WEIGHT OF SAID ELEVATING STRUCTURE TO THE TOP STEP OF SAID LADDER, AND SELECTIVELY RELEASABLE MEANS TO HOLD THE ELEVATING STRUCTURE IN POSITION RELATIVE TO SAID FRAMEWORK.