US2261479A

US2261479A - Extension stepladder

Info

Publication number: US2261479A
Application number: US323209A
Authority: US
Inventors: Moen Clarence
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-03-09
Filing date: 1940-03-09
Publication date: 1941-11-04
Anticipated expiration: 1958-11-04

Description

C. MOEN EXTENSION STEPLADDER Nov. 4, 1941.

Filed March 9, 1940 INVENToR. C/U/'e/f Noe/7 Patented Nov. 4, 1941 UNITED STATES PATENT OFFICE` EXTENSION STEPLADDER Clarence Moen, Spokane, Wash.

Application March 9, 1940, Serial No. 323,209

4 Claims.

This invention relates to a step ladder and more particularly to an extension step ladder, it being one object of the invention to provide an extension step ladder wherein the main ladder section is slidably engaged with the auxiliary ladder section and the auxiliary ladder section is provided with steps mounted for movement from lowered position, where they are out of the Way, to extended position for engaging under steps of the main ladder section where they serve to support the main ladder section as well as being in position for use when climbing the ladder.

Another object of the invention is to provide the ladder with an improved rear prop formed of upper and lower sections, the upper prop section having its upper end pivotally mounted for swinging movement to angularly adjusted positions, there being also a brace carried by the main ladder section near its lower end and engaging the lower portion of the upper prop section to angularly adjust the prop as the main ladder section is raised or lowered and hold the prop in the angularly adjusted position.

Another object of the invention is to provide the main ladder section with side rails having rearwardly extending upper portions carrying a shelf and braced by side plates which also constitute means for pivotally carrying a cross bar to which the upper end of the upper prop section is secured.

Another object of the invention is to provide the auxiliary ladder section with side extensions constituting side braces or props which will serve very effectively to prevent the ladder from tilting over when in use.

Another object is to provide improved means.

for securing the rear prop `in folded position close against the ladder sections when. the ladder is not in use, the brace for the rear prop being pivotally mounted to permit movement of the rear prop to the position close against the ladder sections.

The invention is disclosed in the accompanying drawing, wherein:

Fig. l is a perspective View of the improved extension ladder, showing the same ready for use with the main ladder section in lowered position.

Fig. 2 is a fragmentary View taken transversely through one side of the ladder on the line 2-2 of Fig. 1.

Fig. 3 is a similar view taken through the same side of the ladder on the line 3-3 of Fig. l.

Fig. 4. is a sectional View taken vertically through the rear prop and the upper portion of the main ladder section, on the line 4 4 of Fig. 1.

Fig. 5 is a perspective view on an enlarged scale, showing a step of the auxiliary ladder section in extended position for use, the dotted lines indicating the folded or collapsed position of the step. Y

This improved extension ladder has a main ladder section I and an auxiliary ladder section 2 which may be referred to as a stationary ladder section as the main ladder section slides vertical relative to the auxiliary ladder section during raising or lowering of the main ladder section. A suitable number of steps 3 extend between the side rails 4 of the main ladder section and welded or otherwise firmly secured thereto, and it should be noted that upper ends of the side rails 4 are bent rearwardly to form arms 5 constituting supports for a shelf or platform 6 which is formed of sheet metal and welded or otherwise firmly secured upon the arms. Triangular side plates 1 are secured to the arms and the adjacent portions of the side rails 4 to brace the arms 5 and the shelf carried thereby and, in addition, serve to carry a cross bar 8 which extends between the side plates under the arms 5 and the shelf and is pivotally engaged with the side plates at 8.

The auxiliary ladder section also has side rails 9 formed of metal tubing of the same diameter as that used for the side rails 4 of the main ladder section and having their lower portions bent to form arms I 0 extending from opposite sides of the lower end of the auxiliary ladder section. At their outer ends, the side arms I IJ are welded to lower ends of braces II which are also formed of metal tubing and extend upwardly at an inward incline with their upper ends welded to brackets I2. These brackets I2 have curved rear portions I3v fitting about and welded to the side rails 9 of the auxiliary ladder section, and forward portions of the brackets carry fingers I4 and I5 between which the side rails of the main ladder section are slidably received. A second set of brackets I6 are mounted adjacent the lower end of the ladder and have curved forward portions I 1 welded to side rails of the main ladder section and curved fingers I8 slidably engaging the side rails of the auxiliary ladder section. It will thus be seen that the main ladder section may be shifted vertically relative to the auxiliary ladder section and that sliding movement of the main ladder section will be guided by the brackets.

The auxiliary ladder section is provided with steps as well as the main ladder section, these steps, which are indicated in general by the numeral I9, being carried by cross bars extending between and welded or otherwise firmly secured to the side rails 9 of the auxiliary ladder section. Referring to Fig. 5, it will be seen that each step I9 consists of a metal sheet having front and rear portions bent to form side flanges 2| and 22 to which end strips 23 have their end portions welded or otherwise rmly secured. Against under faces of the end strips are se`- cured short bars 24 which project outwardly from ends of the step and constitute abutment lugs for engaging the front portions of the side rails 9 and supporting the step in extended position for use. The steps are of such length that they may be tilted about the cross bars 20 and then slid downwardly to collapsed position, in which position they are suspended from the cross bars between the side rails 9, as indicated by dotted lines in Fig. 5. It will thus be seen that when the main ladder section is in lowered position, the steps of the auxiliary ladder section will be suspended in vertical position from the cross bars 20 where they will be out of the way and that when the main ladder section is shifted upwardly to raised or extended position, the steps of the auxiliary ladder section may bel shifted upwardly and forwardly about the cross bars to extended position where they will be held by the abutment arms 24 and engage under the steps 3 of the main ladder section and serve as supports for the main ladder section, as well as constituting steps for the lower portion of the ladder. The upper cross bar of the auxiliary ladder does not carry a step as this cross bar serves as a carrier for a cleat 25. The lower step 26 of the auxiliary ladder section is welded to lower portions of the side rails 9 and is formed with a rearwardly extending tongue or arm 21 having slots 28 formed therein.

In order to support the ladder in upright position for use, there has been provided a rear prop 29 formed of telescoping upper and

lower sections

30 and 3|. The two prop sections are formed of metal tubing which is rectangular in cross section and slit along the front of the prop, the upper end of the upper prop section being firmly secured to the cross bar 8 and the lower end of the lower prop section being closed by a block 32 carrying a castor 33. This castor rests on the ground and, together with the castors 34, carried by lower ends of the braces Il, allow the ladder to be easily moved from place to place. Brakes 35 are carried by the castors 34 to prevent unintended movement of the ladder from the position in which it is to be used.

In order to expand the telescoping prop when the main lad-der section is raised, a cable 36 isA anchored at 36 to the upper end of the prop section 30. The cable extends downwardly and into the prop about a pulley 31 carried by a block welded in the lower end of the upper prop section. The cable is then carried upwardly through the upper prop section and about a pulley 38 at the upper end thereof, after which the cable is brought forwardly for engagement with the cleat 25. By grasping the main section by the step 3 and raising upward, the prop 3| will raise causing a downward pull on section 3| through cable 36 and maintain the prop sections in a lengthened position. The steps of the auxiliary ladder section will then be moved to extended position for engaging under the steps 3, thus supporting the main ladder section.

To brace the rear prop there has been provided a brace 39 consisting of metal bars 40 having their front ends pivoted to rear ends of the brackets I6 by pins 4|. 'Ihese bars extend rearwardly from the brackets in converging relation to each other and adjacent their rear ends are bent to form parallel portions which are secured by pins 40' and 4|' and provide a shank or neck 42. The neck is curved longitudinally and extends into the upper prop section through the registering slots formed in the prop sections. The pin 4|' projects from opposite sides of the shank or neck and carries rollers 43 which bear upon the block 31 carrying the roller 31 and not only support the brace for tilting movement but also serve to prevent the shank or neck from slipping out of the prop. The brace moves vertically with the main ladder section and as it moves upward serves to shift the rear prop rearwardly to angularly adjusted position in which it will properly support the ladder in upright position. Since the brace is `pivoted to the brackets I6 it may be swung upwardly to folded position and move the rear prop to a position close against the ladder, the hooks 45 carried by the lower prop section being then engaged through the slots 28 of the step 26 to secure the prop in place.

Having thus described the invention, what is claimed is:

l. In an extension ladder, a main ladder section, an auxiliary ladder section back of the main ladder section, a rear prop having a lower section and an upper section slidable longitudinally of the lower prop section and having its upper end pivoted to the main section, pulleys carried by the upper prop section adjacent upper and lower ends thereof, a cable secured adjacent the upper end of the lower prop section and extending downwardly and then upwardly in engagement with said pulleys and constituting means for shifting the upper prop section and the main ladder section upwardly, means to support the main ladder section in raised position, and a brace carried by the main ladder section and extending rearwardly therefrom with its rear end engaging the upper prop section.

2. In an extension ladder, a main ladder section, an auxiliary ladder section back of the main ladder section, a rear prop having a lower section and an upper section slidable longitudinally of the lower prop section and having its upper end pivoted to the main section, pulleys carried by the upper prop section adjacent upper and lower ends thereof, a cable secured adjacent the upper end of the lower prop section and extending downwardly and then upwardly in engagement with said pulleys and constituting means for shifting the upper prop section and the main ladder section upwardly, brackets carried by the main ladder section at opposite sides thereof, bracing arms pivoted to said brackets and extending rearwardly therefrom with their rear ends extending into the upper prop section through a slot formed vertically in the lower prop section, and supported upon the upper prop section for movement therewith during upward and downward movement of the main ladder section and the upper prop section.

3. In an extension ladder, main and auxiliary ladder sections, the main ladder section having side rails provided with rearwardly extending upper portions, a platform carried by said upper portions of said side rails, side plates carried by upper portions of the side rails, a cross bar pivotally mounted between said side plates, a prop having a lower section and an upper section slidable in the lower section and at its upper end secured to said cross bar, a block adjacent the lower end of the upper prop section, brackets at opposite sides of the lower end of the main ladder section, bracing'bars pivoted to said brackets and extending rearwardly therefrom with their rear ends extending into the prop sections through a slot in the lower prop section and resting upon said block, and means for shifting the upper prop section upwardly and raising the main ladder section, said bracing bars moving with the main ladder section and the upper prop section and tilting the prop to adjusted position.

4. In an extension ladder, main and auxiliary ladder sections having side rails, a cross bar pivoted transversely between upper portions of the side rails of the main ladder section rearwardly of the auxiliary ladder section, a prop having telescoping upper and lower sections, the upper prop section being secured at its upper end to said cross bar, arms extending laterally from opposite sides of the lower end of the auxiliary ladder section, diagonal braces extending upwardly from outer ends of said arms and having brackets at their upper ends secured to side rails of the auxiliary ladder section and slidably engaging side rails of the main ladder section, brackets secured to lower ends of side rails of the main ladder section and slidably engaging side rails of the auxiliary ladder section, a brace pivoted to the lower brackets and extending rearwardly therefrom and engaging the upper prop section, and means for shifting the upper prop section vertically to raise and lower the main ladder section.

CLARENCE MOEN.