GB2345082A

GB2345082A - Extendible ladder stile

Info

Publication number: GB2345082A
Application number: GB9929735A
Authority: GB
Inventors: Christopher Jonathan Waller
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-12-16
Filing date: 1999-12-16
Publication date: 2000-06-28
Also published as: GB9929735D0; GB9827665D0

Abstract

An extendible ladder stile (2, fig 1 not shown) has a first means of engagement (14) on the stile (6) which can be urged against a second means of engagement on the strut (8), so that the strut (8) can be fixed in a number of different positions. The second engagement means can be moved perpendicular to the movement of the strut by a threaded bolt (figs 5 and 6, not shown), where the strut (8) is preferably in the shape of a rectangular block and is held captive by the stile (6). The engagement means may be in the form of toothed racks (14, 36) and there can be a foot section (26) with a curved base (28) at the end of the strut. There is also described a bracket assembly having similar engagement means which attaches an extendible strut to the stile (70 and 71, fig 8 not shown). Such an arrangement allows the strut to pivot relative to the stile (figure 8a, not shown).

Description

EXTENDIBLE STILE ASSEMBLY FOR A LADDER The present invention relates to an extendible stile assembly for a ladder and is concerne, particularly although not exclusively, with a ladder comprising a pair of extendible foot assemblies.

The term'stile'refers to the members or rails of a ladder which are separated by a series of transverse rungs or steps.

Ladders are often used in areas where the ground is uneven and it can be difficult to provide the base of the ladder with a safe footing. There is also a problem of providing a safe footing when using a ladder on a step or a staircase. Similar problems are encountered when trying to place the top of the ladder against an uneven surface as the ladder tends to wobble when a person approaches the top of the ladder.

According to a first aspect of the present invention there is provided a extendible ladder stile assembly comprising first engageable means at one end of the ladder stile, an extendible strut comprising second engageable means, and means to urge one of the engageable means into contact with the other engageable means.

In use when the first and second engageable means are in contact the extendible strut remains fixed relative to the ladder stile. When the first and second engageable means are not in contact the extendible strut can be moved relative to the end of the ladder stile such that the overall length of the extendible ladder stile assembly can be changed.

Preferably at least one of the engageable means is formed with a plurality of location means the arrangement being such that the extendible strut can be fixed at a plurality of different positions relative to the end of the ladder stile.

The second engageable means is preferably substantially received by a recess formed in the extendible strut and said second engageable means is moveable within the recess relative to the extendible strut. The movement of the second engageable means is preferably substantially in a direction perpendicular to the longitudinal axis of the extendible strut.

The urging means is preferably a threaded bolt which acts on the second engageable means.

The extendible strut is preferably held captive by the ladder stile and is in sliding contact therewith.

The extendible strut is conveniently in the form of a substantially rectangular block.

The engageable means formed with the plurality of location means is preferably in the form of a toothed rack.

Preferably both of the engageable means are in the form of toothed racks.

The respective teeth of the toothed racks are adapted to engage with each other.

The extendible strut preferably comprises a foot section disposed at the distal end of the member. The foot section is preferably formed with a curved base.

According to a second aspect of the present invention there is provided a ladder stile extending assembly, the assembly comprising a bracket including first engageable means, an extendible strut comprising second engageable means, and means to urge one of the engageable means into contact with the other engageable means.

In use the bracket is fixed to the end of a ladder stile, the arrangement preferably being such that when the first and second engageable means are not in contact the extendible strut can be moved relative to the bracket and the ladder stile such that the overall length of the ladder stile and extending assembly can be changed.

Preferably at least one of the engageable means is formed with a plurality of engaging positions the arrangement being such that the extendible strut can be fixed at a plurality of different positions relative to the bracket.

The bracket is preferably formed with a tube portion that receives the extendible strut. The bracket preferably comprises means by which the bracket is detachably fixed to the end of a ladder stile. Said means to fix the bracket to the stile preferably comprises a tubular section adapted to receive the end portion of the stile. The tubular section preferably comprises locking means to secure the bracket to the ladder stile.

The second engageable means is preferably a rack of teeth extending along the length of the extendible strut. The first engaging means is preferably formed with a portion shaped to engage with the toothed rack of the second engageable means.

The first engaging means preferably comprises a pivotal connection about which, when in use, said engaging means pivots.

The urging means preferably comprises a resilient structure which acts on the first engageable means. Preferably, the resilient structure is a spring.

The spring is preferably a compression spring.

The urging means preferably comprises a locking device that restricts the rotational movement of the first engageable means about the pivot and holds the lever in contact with the rack of teeth.

The lever preferably comprises a toothed rack being attached to the pivot at one end and being formed with a handle portion at the opposite end.

Preferably both of the engageable means are in the form of toothed racks.

The extendible strut preferably comprises an adjustable pad attached at one end of the strut. The pad preferably comprises a layer of non-slip material. The adjustable pad is preferably attached to the strut by a pivot joint. The pivot joint is preferably a universal ball joint.

The ladder stile extending assembly preferably comprises means to stop the extendible strut from rotating about its longitudinal axis. The means to stop the extendible strut from rotating preferably comprises a channel section formed along the length of the strut and a lobe extending from the inner wall of the tube portion of the bracket that receives the extendible strut, the arrangement being such that the lobe is received by the channel.

The invention can be put into practice in various ways but two embodiments will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a first embodiment of the invention and is a front view of a ladder comprising an extendible stile assembly, Figure la shows a side view in direction 3 of the ladder shown in Figure 1, Figure 2 shows a front view of one end of the ladder of Figure 1 with the extendible member removed, Figure 3 shows a side view of the end of the ladder shown in Figure 2, Figure 4 shows a plan view of the ladder shown in Figure 2, Figure 5 shows a front view of the extendible member shown in Figure 1, Figure 6 shows a side view of the extendible member shown in Figure 5, Figure 7 shows a plan view of the extendible member shown in Figure 5.

Figure 8 shows a second embodiment of the invention and is a front elevation of a ladder comprising an extendible stile assembly, Figure 8a shows a side view in direction 53 of the ladder shown in Figure 8, Figure 9 shows a side view of the extendible strut shown in Figure 8, Figure 10 shows a plan view of the extendible strut shown in Figure 9, Figure 11 shows a front view of the bracket shown in Figure 8, and Figure 12 shows a plan view of the bracket shown in Figure 11 with the curved lever removed for clarity.

Referring to the Figures 1 to 7, a ladder 1 comprises an extendible stile assembly 2, the stile assembly 2 comprising a first engageable member 4 at one end of the ladder stile 6, an extendible strut 8 comprising a second engageable member 10 and means 12 to urge the second engageable members 10 into contact with the first engageable member 4.

The ladder 1 comprises two substantially parallel stiles 6 (only one stile is shown in the Figures). The two stiles are connected together by a plurality of rungs 17. The stile 6 is a Universal column having a'I' shaped cross-section. The stile 6 comprises a central web 18 and two flanges 19, 20 extending perpendicularly from the respective ends of the central web 18. The distal edges of the flange 19 curve inwardly in a direction towards the flange 20 and the distal edges of the flange 20 curve inwardly in a direction towards the flange 19 so forming channels 22 and 22'.

The first engageable means 4 is a rack of teeth 14. The rack 14 extends from the end of the central web 18 in a direction parallel to the axis of the stile 6 towards the other end of the web 18. The rack 14 is attached to the web 18 by six rivets 23. Alternatively, the rack could be welded to the web 18.

The extendible strut 8 comprises a slider in the form a rectangular block 24, and a foot section 26 extending substantially perpendicularly from one end of the strut 8. The foot section 26 is formed with a curved base 28. The curved base 28 provides good contact with the ground when the ladder is tilted at an angle (see Figure la). The block 24 is formed with a rectangular central channel 30 extending longitudinally along the length of the block 24. On the opposite side to the channel 30 the block 24 is formed with two corner cut outs 32,34 extending long the length of the block 24.

The second engageable means 10 is a rack of teeth 36 disposed within a square recess 38 which extends from the surface of the central channel 30. The rack 36 is movable within the recess 38.

The urging means 12 comprises a threaded bolt 40 which is screwed into a corresponding threaded hole 41 which extends through the block 24, and a turning handle 42. When the handle 42 is turned in a clockwise direction the bolt 40 travels towards the rack 36. When the bolt 40 is continually rotated the distal end of the bolt 40 will abut the innermost surface of the rack 36 and the bolt 40 urges the rack 36 out of the recess 38 in a direction 44.

When the rack 36 is fully retracted within the recess 38 the outermost tips of the teeth are substantially flush with the surface of the channel 30.

The extendible strut 8 is then able to be inserted into the channel 22 in a direction along the longitudinal axis of the stile 6 (as shown in Figures 1 and la). The respective curved distal ends 50, 52 of the flanges 19, 20 extend over, and are in sliding contact with, the respective corner cut outs 32,34. The channel section 30 allows the strut 8 to pass over the rack 4 of the stile 6.

If the ladder 1 is on an uneven ground or used on a step the strut 8 can be extended to allow the ladder 1 to be correctly positioned. The strut 8 will compensate for the uneven surface. The strut 8 is fixed in the desired extended position by turning the handle 42 and engaging the two racks 36 and 14 with each other. The urging means 4 locks the two racks 36,14 together.

The racks 36,14 are made out of suitably strong material such as aluminium or other metals.

Each end portion of each of the stiles can comprise an extendible stile assembly as herein before described.

There is no particular limit to the length of extension achievable by the present invention. If required a extra long strut and corresponding rack can be used to provide a large extension for a ladder stile.

However, because the maximum step height of a set of stairs is 220mm it would be convenient to provide the stile with a range of extension from zero to 230mm. Once the stile length has been increased by the height of one step using the invention the ladder can be moved up and down a staircase without the need for further adjustment of the invention.

It will be appreciated that the rack 14 can be fitted to the ladder stile 6 during the manufacture of the ladder. Alternatively a ladder can be retrofitted with the rack 14 after the ladder has been sold.

The extendible strut 8 can be made of any suitable material such as aluminium, plastic or wood.

Referring to Figures 8 to 12 there is shown a second embodiment of the invention. A ladder stile extending assembly 50 comprises a bracket 52 including first engageable means in the form of a curved lever 54, and an extendible strut 56 including second engageable means in the form of a rack of teeth 58 extending along the length of the strut.

The ladder stile extending assembly 50 provides means to extend the length of the stile of any type of ladder.

The rack of teeth 58 are formed within a longitudinal channel 60 that extends along the length of the strut 56. The strut 56 is formed with a second channel 62 which extends along the length of the strut. The second channel 62 has a rectangular cross-section. At the base of the strut 56 there is an adjustable pad 64 attached to the strut 56 by a universal joint arrangement 66.

The bracket 52 comprises two tube sections 70, 71. The section 70 is formed with a substantially circular bore 72 shaped to receive the strut 56. The curved lever 54 is contained substantially within the bore 72 and is attached to the section 70 by a pivot 74. The curved lever 54 is formed with a number of teeth 76 that are shaped to correspond with the rack of teeth 58. At the distal portion of the lever 54 there is a handle pad 80. The pad 80 is used by the operator of the assembly to rotate the lever 54 about the pivot 74. There is a groove 83 which extends away from the bore 72. The groove 83 has a square cross-section which is wide enough to receive the teeth portion of the lever 54. A compression spring 82 is disposed within the groove 83 between the inner wall of the section 70 and the lever 54. The spring 82 urges the lever 54 in an anticlockwise direction about the pivot 74. Extending radially inwardly from the inner wall of the bore 72 is a locating lobe 84.

When the strut 56 is inserted into the bore 72 the lobe 84 slides within the channel 62. The curved lever 54 is rotated, by an operator, in a clockwise direction about the pivot 74 so withdrawing the teeth of the lever 54 away from the rack of teeth 58 of the strut 56 and compressing the spring 82. When the handle pad 80 is released the spring 82 urges the teeth 76 of the lever 54 into contact with part of the rack 58 and the respective teeth engage with each other. The lever 54 and rack 58 are secured together by tightening a threaded bolt 55 against the lever 54 so preventing rotational movement of the lever 54 about the pivot 74.

The tube section 71 of the bracket 52 has a rectangular cross-section and forms a bore 88. When in use a ladder stile 90 is inserted into the section 71 through bore 88 and rests on a retaining bar 92 (see Figure 8).

The end portion of the ladder stile 90 is secured to the bracket 52 by a threaded bolt 94. When tightened the bolt 94 abuts the side of the end portion of the ladder stile 90.

All four ladder stile ends can be provided with extension assemblies as herein before described. The extendible stile assemblies are adjusted to compensate for uneven surfaces. The assemblies are especially effective when the ladder is used on a set of stairs.

Tube section 70 is attached to tube section 71 by a threaded pivot shaft 96 which is received by a bore formed with an internal screw thread.

The shaft 96 extends through the section 71 wall and into the wall of section 70. On the opposite side to the shaft 96 section 70 includes a lobe portion 98 formed with an internal screw threaded bore extending therethrough. The lobe portion 98 receives a threaded grub screw 99.

Section 71 is formed with two holes 100,102 that extend through the wall of section 71. The two respective axes of the holes 100,102 are equidistant from the axis of the pivot shaft 96. When the grub screw 99 is withdrawn the section 70 may rotate about the pivot shaft 96. The angle of incline of the section 71 with respect to section 70 can be altered by aligning the grub screw 99 with either of the holes 100,102. The incline of the section 71 is fixed by screwing the grub screw 99 into either of the holes 100,102.

When in use if the righthand stile of the ladder requires an extending assembly 50 the grub screw 99 would be screwed into the hole 100. If, on the other hand, the lefthand stile of the ladder requires an extending assembly 50, the grub screw 99 would be screwed into the hole 102.

Figure 8a shows the section 71 inclined at an angle to the substantially vertical section 70. The grub screw 99 is located within the uppermost hole 100.

The stile extending assembly 50 can be made out of any suitable material, such as aluminium.

Claims

CLAIMS 1. An extendible ladder stile assembly comprising first engageable means at one end of the ladder stile, an extendible strut comprising second engageable means, and means to urge one of the engageable means into contact with the other engageable means.
2. An extendible ladder stile as claimed in claim 1 wherein at least one of the engageable means is formed with a plurality of location means the arrangement being such that the extendible strut can be fixed at a plurality of different positions relative to the end of the ladder stile.
3. An extendible ladder stile as claimed in claim 1 or claim 2 wherein the second engageable means is substantially received by a recess formed in the extendible strut and said second engageable means is moveable within the recess relative to the extendible strut.
4. An extendible ladder stile as claimed in claim 3 wherein the movement of the second engageable means is substantially in a direction perpendicular to the longitudinal axis of the extendible strut.
5. An extendible ladder stile as claimed in any one of the previous claims wherein the urging means is a threaded bolt which acts on the second engageable means.
6. An extendible ladder stile as claimed in any one of the previous claims wherein the extendible strut is held captive by the ladder stile and is in sliding contact therewith.
7. An extendible ladder stile as claimed in any one of the previous claims wherein the extendible strut is in the form of a substantially rectangular block.
8. An extendible ladder stile as claimed in any one of the claims 2 to 7 wherein the engageable means formed with the plurality of location means is in the form of a toothed rack.
9. An extendible ladder stile as claimed in any one of the previous claims wherein both of the engageable means are in the form of toothed racks ; the respective teeth of the toothed racks being adapted to engage with each other.
10. An extendible ladder stile as claimed in any one of the previous claims wherein the extendible strut comprises a foot section disposed at the distal end of the member.
11. An extendible ladder stile as claimed in claim 10 wherein the foot section is preferably formed with a curved base.
12. A ladder stile extending assembly, the assembly comprising a bracket including first engageable means, an extendible strut comprising second engageable means, and means to urge one of the engageable means into contact with the other engageable means.
13. A ladder stile extending assembly as claimed in claim 12 wherein in use the bracket is fixed to the end of a ladder stile, the arrangement being such that when the first and second engageable means are not in contact the extendible strut can be moved relative to the bracket and the ladder stile such that the overall length of the ladder stile and extending assembly can be changed.
14. A ladder stile extending assembly as claimed in claim 12 or claim 13 wherein at least one of the engageable means is formed with a plurality of engaging positions the arrangement being such that the extendible strut can be fixed at a plurality of different positions relative to the bracket.
15. A ladder stile extending assembly as claimed in any one of the claims 12 to 14 wherein the bracket is formed with a tube portion that receives the extendible strut.
16. A ladder stile extending assembly as claimed in any one of the claims 12 to 15 wherein the bracket comprises means by which the bracket is detachably fixed to the end of a ladder stile.
17. A ladder stile extending assembly as claimed in claim 16 wherein the means to fix the bracket to the stile comprises a tubular section adapted to receive the end portion of the stile.
18. A ladder stile extending assembly as claimed in claim 17 wherein the tubular section comprises locking means to secure the bracket to the ladder stile.
19. A ladder stile extending assembly as claimed in any one of claims 12 to 18 wherein the second engageable means is a rack of teeth extending along the length of the extendible strut.
20. A ladder stile extending assembly as claimed in any one of claims 12 to 19 wherein the first engaging means is formed with a lever portion shaped to engage with the toothed rack of the second engageable means.
21. A ladder stile extending assembly as claimed in any one of claims 12 to 20 wherein the first engaging means comprises a pivotal connection about which, when in use, said engaging means pivots.
22. A ladder stile extending assembly as claimed in any one of claims 12 to 21 wherein the urging means comprises a resilient structure which acts on the first engageable means.
23. A ladder stile extending assembly as claimed in claim 22 wherein the resilient structure is a spring.
24. A ladder stile extending assembly as claimed in claim 23 wherein the spring is a compression spring.
25. A ladder stile extending assembly as claimed in any one of claims 21 to 24 wherein the urging means comprises a locking device that restricts the rotational movement of the first engageable means about the pivot and holds the lever portion in contact with the rack of teeth.
26. A ladder stile extending assembly as claimed in any one of claims 20 to 25 wherein the lever portion comprises a toothed rack being attached to the pivot at one end and being formed with a handle portion at the opposite end.
27. A ladder stile extending assembly as claimed in any one of claims 20 to 26 wherein both of the engageable means are in the form of toothed racks.
28. A ladder stile extending assembly as claimed in claim 27 wherein the respective teeth of the toothed racks are adapted to engage with each other.
29. A ladder stile extending assembly as claimed in any one of claims 20 to 28 wherein the extendible strut comprises an adjustable pad attached at one end of the strut.
30. A ladder stile extending assembly as claimed in claim 29 wherein the pad comprises a layer of non-slip material.
31. A ladder stile extending assembly as claimed in claim 30 wherein the adjustable pad is attached to the strut by a pivot joint.
32. A ladder stile extending assembly as claimed in claim 31 wherein the pivot joint is a universal ball joint.
33. A ladder stile extending assembly as claimed in any one of claims 12 to 32 wherein the ladder stile extending assembly comprises means to stop the extendible strut from rotating about its longitudinal axis.
34. A ladder stile extending assembly as claimed in claim 33 wherein the means to stop the extendible strut from rotating comprises a channel section formed along the length of the strut and a lobe extending from the inner wall of the tube portion of the bracket that receives the extendible strut, the arrangement being such that the lobe is received by the channel.
35. A ladder stile extending assembly as substantially herein described with reference to the accompanying drawings.
36. An extendible ladder stile as substantially herein described with reference to the accompanying drawings.