US2021494A

US2021494A - Folding ladder

Info

Publication number: US2021494A
Application number: US19047A
Authority: US
Inventors: Zeman Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-04-30
Filing date: 1935-04-30
Publication date: 1935-11-19
Anticipated expiration: 1952-11-19

Description

P. ZEMAN FOLDING LADDER Nova 19, 1935.

Filed April 30, 1935 2 Sheets-Sheet 2 INVENTOR PA UL. Z EMAN 4; ATTORNEY Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE 3 Claims.

My invention relates to improvements in folding step ladders and has for an object to provide a collapsible and foldable step ladder which is of strong and durable construction. Another object is to provide a collapsible step ladder which may readily be extended either to its full extent making available for use every step of its complement of steps, or may be extended to a lesser degree, bringing into operative position one or more steps as occasion may require.

Another object of the invention is to so arrange the parts of a folding step ladder that when the front and back portions are spread apart each will present a series of steps, a further object being to form such parts as collapsible and extensible members.

Another object of the invention is to so form the front and rear portions of a duplex ladder that these portions may be reassembled as a double length extension ladder.

A further object of the invention is toprovide an extensible and contractible tension cable for holding the parts of an extension ladder firmly in its various positions of adjustment.

In the drawings accompanying this specification and forming part of the application, I have illustrated one practicable form of the invention, which at the present time may be regarded as the preferred form, in which drawings,

Fig. 1 is a front view of a ladder made in accordance with my invention, the side frames being shown as collapsible and the steps as folded;

Fig. 2 is a side elevation of the device shown in Fig. 1. In this view the front and rear members of the ladder are shown folded together.

Fig. 3 is a view taken at about the plane 3-3 of Fig. 2 looking down.

Fig. 4 is a longitudinal section of two of the telescoping members showing one of the steps partly broken away and the holding dog in position.

Fig. 5 is an end View of the ladder showing the front and rear portions extended and the ladder sections drawn out so these are extended rep-- resenting the step ladder in its normal complete height and Fig. 6 is a view on a smaller scale showing the manner in which the front and rear members of the ladder may be connected together in one continuous ladder of the straight ladder type.

The ladder in the form illustrated comprises what might be termed front and rear ladder portions 1 and B which are joined together at the upper portion by means of a head member 9 which carries the top step or platform Ill. The

front and rear members are shown provided with spreading feet II and I2 for resting upon the ground or floor when the ladder is in use or stored in an operative position.

The front and rear sections are shown'as each 5 made up of a number of telescoping members, each carrying a step. In the illustration there are shown five. of these telescoping members which may be designated by the reference character [3, the lowermost of which has secured to 10 it the feet II and i2. The upper element I4 of the front ladder portion is made fast with the head member 9 and platform step I0; the upper member [5 of the rear ladder portion is shown pivoted to the head member 9 by means of a removable pin 16.

In the present illustration there are five steps I! shown for each of the front and rear ladder portions. The uppermost of these steps of the front portion is pivoted to the lower part of the member [4. The successively lower steps are carried by the lower ends of the various members 1.

Associated with each of the steps I! is a pivoted dog l8 which is pressed into its upper posi- 5 tion by means of a spring I9 and passes thru a slot 20 formed in the telescoping members. The pivot 2! for the step and the dog passes thru the side of the telescoping member.

Each of the members 1 is formed with a longitudinal slot 22 in which a pin 23, carried by the lower part of the section immediately above, may move. These slots are to permit the extension of the ladder or the section and to assure that the parts do not over run one another. It will 5 be noted that each slot extends upwardly above the normal position of the parts when in their operative position. This amount of overthrow is for the purpose of permitting the operation of the step and the dog [8 in the movement into and out of operative position.

An extensible and contractible tension cable is provided for the holding of the parts of the ladder firmly in its various positions of adjustment. This cable is carried by a spindle 5 or drum member 24 which has within it a return spring after the principle of that used in shade rollers. The cable is really formed in two parts, one for each side of the ladder and each of the parts is double. By reference to Fig. 1, it will be seen that the cable at the left hand side is doubled at 25 and the cable 26 at the right hand side is doubled, both loops being held by a staple 21. By this means when the drum 24 rotates in a winding direction, the cables are laid on double and each has two extending

ends

28, 29. Each end of the cable is formed with an eye 30 passing over a headed pin 3|, carried by the end of the next to the last telescoping unit 1. The front and rear portions 1 and 8 of the ladder are held in their open position by means of a folding brace 32 pivoted at the front and back by means of removable pins 33. At the center of this brace 32, there is pivoted a pulley wheel 34. The cable 28 which is at the front at the top and bottom of the ladder, is placed around the rear of this pulley and the cable 29 at the top and bottom is passed at the front of this pulley. When the spring within the roller 24 is of proper strength sufficient tension is asserted upon the ladder in its various positions of adjustment to hold the parts steady. When the ladder is in the position as shown in Figs. 1 and 2 and the user wishes to bring but one step in position foruse, he may, without releasing the hook 35 which holds the feet H and 12 together, raise the top step or platform In, a sufficient amount to bring the uppermost steps H into a position where action of the dog l8 and its associated parts will hold it elevated. The tension of the cable is then sufficient to hold the parts in this position while in use or while being moved from place to place. When the operator wishes to spread the front and rear portions apart so that the feet H and I2 rest fiat upon the floor, he merely releases the hook 35 and opens these parts. In this position, the uppermost step in the front and in the rear is in position for use and the top of the platform It! is substantially parallel with the ground. As the operator needs additional steps for use, he merely has to raise the top platform against the tension of the cable operating spring a suflicient distance to permit the release of the additional steps and the engagement of the dogs I8 in the upper slots.

In Fig. 5 the ladder is shown with all its telescoping sections fully extended and the front and rear portions open to their fullest extent. In this position there are steps in both the front and rear portions. Of course, if one wishes to use the ladder in the form illustrated in Fig. 5 as an ordinary step ladder they are not necessary altho for certain uses step ladders are made with steps or rungs in both the front and rear.

Should the user wish a ladder twice the length of the ladder in the Fig. 5 position, he then removes the brace 32 from its illustrated position and removes the cable from the pins 3!. He then removes the pin is at the top of the rear section, turns the rear of that section toward the front and secures its upper portion below the foot H, passing the pin I6 thru the hole 36 provided for that purpose. He then fastens the respective ends of the brace 32 to the lower part of what was originally the front and to the top of the part which was originally the rear section, making it into a V shape and passes the cable over the pulley 34 and secures its eye 30 to the lowermost pin 3|. 5

Having thus described my invention, I claim and desire to secure by Letters Patent:

1. In a collapsible and expansible ladder, the combination with a foot member and a series of members for telescoping with the foot member, 1 of a series of steps, there being a step pivoted at its rear portion to the lower end of each of the telescoping members, a holding dog associated with each of the steps and extending thru slots formed in the telescoping members, spring means 15 active upon the dog for raising it into operative position, the length of the dog being of such proportion in relation to the inside dimension of the telescoping members that except when the dog is opposite the slots provided for it, it and the associated step are held in a closed position, the organization being such that upon the extension of any two of the members telescoping one with the other and upon the registering of the slots therein the dog pertinent to those slots extends thru them and holds the associated step in operative position.

2. In a collapsible and expansible ladder, the combination with a foot member and a series of members for telescoping with the foot member, so of a series of steps, there being a step pivoted at its rear portion to the lower end of each of the telescoping members, a head member secured to the uppermost of the telescopic members, a spring roller carried by the head member, a tension cable 35 Wound upon the spring roller and means carried by the foot member for the attachment of the cable.

3. In a collapsible and expansible ladder, the combination with a foot member and a series of members for telescoping with the foot member, of a series of steps, there being a step pivoted at its rear portion to the lower end of each of the telescoping members, a head member secured to the uppermost of the telescopic members, a top platform step carried by the head member,

a spring roller carried by the head member, a tension cable wound upon the spring roller and means carried by the foot member for the attachment of the cable, a holding dog associated with each of the steps, and extending thru slots. formed in the telescoping members, the organization being such that upon the extension of any two of the members telescoping one with the other and upon the registering of the slots therein the dog pertinent to those slots extends thru them and holds the associated step in operative position.

PAUL ZEMAN.