GB1563049A

GB1563049A - Collapsible ladders

Info

Publication number: GB1563049A
Application number: GB4689077A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-11-10
Filing date: 1977-11-10
Publication date: 1980-03-19

Description

(54) IMPROVEMENTS IN COLLAPSIBLE LADDERS (71) I, HEIMER ANDERSSON, a Swedish subject, of PL 1722, S-310 40 Harplinge, Sweden, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to collapsible ladders of the type consisting of a plurality of sections including one bottom section and one or more upper sections, the said sections being longitudinally displaceable with respect to each other between a retracted position and an extended position determined by a catch and comprising a pair of stiles and at least two rungs.

The invention has for its principal object the provision of a ladder of the type indicated which in the fully retracted state occupies a particularly small space in all directions while still forming a unit ready for immediate extension into the desired length.

The invention accordingly consists in a ladder of the type above specified in which each of the stiles of the one or more upper sections has a sectional shape allowing it to telescope into the adjoining lower stile and in which the uppermost rung of each of the sections is fixedly mounted in the stiles and in which the stiles, of said one or more upper sections is provided with longitudinal guideways in which end portions of at least the lowermost one of the rungs of the section are displaceable along said stiles between a lower terminal position defined by a stop for each of said end portions and an upper terminal position. The rungs of the bottom section are preferably all fixedly mounted in the stiles of that section.

An example of a ladder according to the invention will now be described with reference to the accompanying drawings. in which: Figure 1 is a front view of the ladder in a fully retracted position, Figure 2 is a sectional view on a greater scale than Figure 1 taken on the line II-II of Figure 1, Figure 3 is a sectional view on the same scale as Figure 1 taken on the same line as Figure 2 through the top section and part of the next section of the ladder, and Figure 4 is a sectional view on a larger scale than Figures 1 to 3 taken on the line IV-IV of Figure 1.

The ladder shown in Figure 1 consists of five ladder sections 1 to 5, comprising one bottom section 1 and four upper sections 2 to 5. The bottom section 1 consists of two stiles 6,6 and three tubular rungs 7 rigidly attached to the stiles 6,6. Each of the upper sections consists of a pair of stiles 8,8, 9,9, 10,10 and 11,11, a top rung 12, 13, 14, 15, respectively, rigidly mounted between the top ends of the respective stiles, and a pair of movable rungs 16 and 17, 18 and 19, 20 and 21 and 22 and 23, respectively. The sectional size of the stiles increases gradually from the top to the bottom of the ladder by the amount required to make each of the stiles fit into the next one so as to allow telescopical motion of the stiles with respect to each other. This is best seen in Figure 4 in which the lower stiles 6, 8, 9 have been omitted in order to simplify the drawing.

One of the stiles 6, 8, 9 10 of each of the ladder sections 1, 2, 3, 4 is equipped at its upper end with a spring catch consisting of a leaf spring 24 attached to the stile and provided at its free end with a stud 25 arranged to snap under the action of the spring into a bore provided in the adjacent stile so as to maintain the same in the extended position.

The movable rungs 16 to 23 extend through and are displaceable along slots provided in each of the stiles 8 to 11. As all of these slots are identically similar, it is sufficient to describe the slot provided in one of the stiles 11. The slot, which is closed at both ends, consists of an upper. wider portion 26a and a lower, narrower portion 26b (Figure 3), the transition between said slot portions forming a shoulder 27 at each edge of the slot. The lower one 22 of the two movable rungs has a diameter slightly less than the width of the narrow slot portion 26b, while the other movable rung 23 has a diameter corresponding to the width of the wider slot portion 26a and, consequently, cannot enter the narrow portion of the slot.

Each of the movable rungs 22, 23 is provided at both ends with a square flange 28 (Figure 4) which engages the wall of the stile 11 on the side facing away from the rung and the other stile 11, while a pair of opposed edges of the flange engage a pair of parallel, straight guide bars 29 attached to the stile 11 and serving in combination with the square flanges 28 to prevent rotation of the rung about its axis. The guide bars 29 are connected by one or more tie members 30 serving mainly to compensate for the loss of strength caused by the slot 26a, 26b.

The corresponding details of the sections 2, 3 and 4 are identically similar to those of the section 5.

In the extended position represented in Figure 3, the lower one 22 of the movable rungs 22, 23 rests on the lower edge of the narrow slot portion 26b, while the upper rung 23 rests on the shoulders 27 at the lower end of the wider portion 26a of the slot. The lower end of the stile 11 is visible at 31 through the slot of the adjacent riser 10.

To retract the top section 5 into the next section 4, the stud 25 is pulled outwards against the action of the spring 24. If the ladder is kept upright, the weight of the top section 5 thus released will cause the stiles 11,11 of the top section to telescope down into the stiles 10,10 of the next section. The rung 22 when arrested by the upper edges of the stiles 10 will move upwards with respect to the slot 26b. 26a, carrying before it the rung 23 until the rung 23 hits the upper end of the slot portion 26a, thus arresting the downward motion of the top section 5.

To make a fully extended ladder telescope into the fully retracted state shown in Figure 1. it is usually preferable first to release the section 2 to cause it to telescope into the section 1, then to release the section 3 to cause it to telescope into the section 2, and so on.

In a modification (not illustrated) the end portions of the rungs are guided in slots having the same width throughout their length and cooperate with selective stop members attached to the stiles.

WHAT I CLAIM IS: 1. A ladder consisting of a plurality of sections including one bottom section and one or more upper sections, the said sections being longitudinally displaceable with respect to each other between a retracted position and an extended position determined by a catch and comprising each a pair of stiles and at least two rungs, in which each of the stiles of the one or more upper sections has a sectional shape allowing it to telescope into the adjoining lower stile and in which the uppermost rung of each of the sections is fixedly mounted in the stiles and in which the stiles of the one or more upper sections are provided with longitudinal guideways in which end portions of at least the lowermost one of the rungs of the section are displaceable along the stiles between a lower terminal position defined by a stop for each of the said end portions and an upper terminal position.

2. A ladder according to Claim 1, wherein all of the rungs of the bottom section are fixedly mounted in the respective stiles.

3. A ladder according to Claim 1 or 2, wherein the or each said upper section comprises, in addition to said fixedly mounted rung and said displaceable lowermost rung, one or more intermediate rungs displaceable longitudinally of said guideways, a pair of stops being provided for each of the said intermediate rungs and being such as to define a particular lower terminal position for the or a respective one of the said intermediate rungs and to allow a free passage for any rung below the respective intermediate rung.

4. A ladder according to any one of Claims 1 to 3, wherein each of the stiles of the said upper section or sections is provided at the side facing the other stile with a longitudinal slot receiving the end portion or portions of said displaceable rung or rungs.

5. A ladder according to Claim 4, wherein the slot has a closed low extremity which constitutes the stop defining the lower terminal position of the lowermost rung of the section.

6. A ladder according to Claim 4 or 5 as dependent from Claim 3, wherein the said slot comprises a number of portions having different widths, the said number being equal to the number of displaceable rungs contained in the section, the width of any of the said portions exceeding the width of the adjoining lower portion, the rung end portions displaceable along the said slot having different widths corresponding to the widths of the said slot portions, whereby the transition between a slot portion and the adjacent narrower slot portion constitutes the stop for catching a corresponding rung end portion.

7. A ladder according to any one of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. sufficient to describe the slot provided in one of the stiles 11. The slot, which is closed at both ends, consists of an upper. wider portion 26a and a lower, narrower portion 26b (Figure 3), the transition between said slot portions forming a shoulder 27 at each edge of the slot. The lower one 22 of the two movable rungs has a diameter slightly less than the width of the narrow slot portion 26b, while the other movable rung 23 has a diameter corresponding to the width of the wider slot portion 26a and, consequently, cannot enter the narrow portion of the slot. Each of the movable rungs 22, 23 is provided at both ends with a square flange 28 (Figure 4) which engages the wall of the stile 11 on the side facing away from the rung and the other stile 11, while a pair of opposed edges of the flange engage a pair of parallel, straight guide bars 29 attached to the stile 11 and serving in combination with the square flanges 28 to prevent rotation of the rung about its axis. The guide bars 29 are connected by one or more tie members 30 serving mainly to compensate for the loss of strength caused by the slot 26a, 26b. The corresponding details of the sections 2, 3 and 4 are identically similar to those of the section 5. In the extended position represented in Figure 3, the lower one 22 of the movable rungs 22, 23 rests on the lower edge of the narrow slot portion 26b, while the upper rung 23 rests on the shoulders 27 at the lower end of the wider portion 26a of the slot. The lower end of the stile 11 is visible at 31 through the slot of the adjacent riser 10. To retract the top section 5 into the next section 4, the stud 25 is pulled outwards against the action of the spring 24. If the ladder is kept upright, the weight of the top section 5 thus released will cause the stiles 11,11 of the top section to telescope down into the stiles 10,10 of the next section. The rung 22 when arrested by the upper edges of the stiles 10 will move upwards with respect to the slot 26b. 26a, carrying before it the rung 23 until the rung 23 hits the upper end of the slot portion 26a, thus arresting the downward motion of the top section 5. To make a fully extended ladder telescope into the fully retracted state shown in Figure 1. it is usually preferable first to release the section 2 to cause it to telescope into the section 1, then to release the section 3 to cause it to telescope into the section 2, and so on. In a modification (not illustrated) the end portions of the rungs are guided in slots having the same width throughout their length and cooperate with selective stop members attached to the stiles. WHAT I CLAIM IS:

1. A ladder consisting of a plurality of sections including one bottom section and one or more upper sections, the said sections being longitudinally displaceable with respect to each other between a retracted position and an extended position determined by a catch and comprising each a pair of stiles and at least two rungs, in which each of the stiles of the one or more upper sections has a sectional shape allowing it to telescope into the adjoining lower stile and in which the uppermost rung of each of the sections is fixedly mounted in the stiles and in which the stiles of the one or more upper sections are provided with longitudinal guideways in which end portions of at least the lowermost one of the rungs of the section are displaceable along the stiles between a lower terminal position defined by a stop for each of the said end portions and an upper terminal position.

7. A ladder according to any one of

Claims 1 to 6, wherein the rung end portions displaceable in the said guideways are adapted to prevent rotation of the rung about its longitudinal axis.

8. A ladder according to any one of Claims 4 to 7, wherein the displaceable rungs are provided each at at least one extremity with a flange or projection arranged to engage the slotted wall of the stile beside the said slot at the side facing away from the rung.

9. A ladder according to Claim 8, wherein the said flange or projection has at least one straight edge and in which the said said wall is provided with a straight guide bar slidably engaging said straight edge.

10. A ladder substantially as described hereinbefore with reference to the accompanying drawings.