Telescopic ladder

Abstract

A folding ladder consists of a first section and a second section, both hinged and attached to the first by two hinge mechanisms. Each hinge mechanism is designed to lock both sections at an angle to each other. The hinge mechanism includes a sliding mechanism and an angle selector to allow manual selection of the angle between the two sections, as well as a locking pin to secure them in the desired angle.

Description

Telescopic ladder Background

[0001] Staircases typically include rungs supported between stiles formed by a plurality of columns. In some cases, the staircase may be a telescopic ladder and can expand to separate the columns from each other for extension, or collapse together for retraction. Such staircases frequently include mechanisms that allow the ladder to be folded for storage and unfolded during use. US patent 5954157A (D1) describes a combination extension ladder and steps made of prestressed filament-wound composite material, such as fiberglass. The inner and outer side rails are made of molded, filament-wound composite material (fiberglass), wherein the fibers are continuous and oriented at an angle to the longitudinal axis of the respective side rails. Hinges are provided on each of the inner side rails of the ladder, and the hinge actuators are located on the front edges of the outer side rails so that the ladder can be folded, unfolded, or locked in a closed, stepped, or straight extension ladder configuration by pressing the hinge actuators, regardless of the longitudinal position of the inner rail sections relative to the outer rail sections.The inner side rails are telescopically mounted within the channeled portions of the outer rails and interconnected with a tongue and groove joint, allowing them to be extended to increase the ladder's height in any configuration without compromising the outer rail's torsional strength under heavy loads. Both the inner and outer side rails feature composite rungs, integrally molded into the sides for a homogeneous casting. Ladder accessories are provided to enhance stability and ease of use during operation. Summary of the invention

[0002] The features of the invention are set forth in claim 1. The preferred features of the invention are set forth in the dependent claims. Brief description of the drawings

[0003] The following drawings are illustrative of particular embodiments of the present invention and therefore do not limit the scope of the invention. The drawings are not necessarily to scale (unless otherwise indicated) and are intended to be used in conjunction with the explanations in the detailed description below. The embodiments of the invention will be described below in this specification together with the accompanying drawings, where similar numbers indicate similar elements.

[0004] Figure 1A is a perspective view of a folding ladder locked in a first angular position according to one embodiment;

[0005] Figure 1B is a perspective view of the folding ladder of Figure 1A locked in a second angular position;

[0006] Figure 2A is a perspective view of the folding ladder of Figure 1A locked in a third angular position shown in a collapsed state;

[0007] Figure 2B is a perspective view of the folding ladder of Figure 2A shown in an extended state;

[0008] Figure 2C is a close-up perspective view of part "2C" of Figure 2B;

[0009] Figure 2D is a left side view of the folding ladder of part "2D" of Figure 1A showing only the rungs of the first and second ladder parts;

[0010] Figure 2E is a sectional plan view of a portion of the staircase showing details of a connector unit according to one embodiment;

[0011] Figure 3 is a perspective view of a hinge mechanism according to one embodiment;

[0012] Figure 4A is a side view of the hinge mechanism of Figure 3 with the selector collar removed from view to show certain details of the hinge mechanism;

[0013] Figure 4B is a perspective side view of the hinge mechanism of Figure 3 shown in an unlocked state with the selection collar removed from view to show certain details of the hinge mechanism;

[0014] Figure 4C is a side view of the hinge mechanism shown in Figure 4B with the second hinge element and the selector collar removed from view to show certain details of the hinge mechanism;

[0015] Figure 5 is a cross-sectional view of a hinge mechanism taken along line 5-5 of Figure 3;

[0016] Figure 6 is a detailed view of the hinge mechanism of Figure 5 with certain components of the first hinge element removed from the view to show certain details of the hinge mechanism;

[0017] Figure 7 is a detailed perspective view of a locking pin, locking plate, selector pin, and deflection spring according to one embodiment;

[0018] Figure 8A is a cross-sectional side view of the hinge mechanism of Figure 5 with certain features removed from the view to show certain details of the hinge mechanism;

[0019] Figure 8B is a close-up view of part 8B of Figure 8A;

[0020] Figure 9A is a perspective view of a folding ladder locked in a first angular position according to one embodiment;

[0021] Figure 9B is a perspective view of the folding ladder of Figure 9A locked in a second angular position in a collapsed state;

[0022] Figure 9C is a perspective view of the folding ladder of Figure 9B shown in an extended state;

[0023] Figure 9D is a perspective view of the folding ladder of Figure 9A locked in a third angular position;

[0024] Figure 10A is a close-up perspective view of part 10A of the staircase shown in Figure 9A;

[0025] Figure 10B is a perspective view of ladder 10A showing the stabilizers in an extended position;

[0026] Figure 10C is a perspective view of ladder 10A showing a stabilizer in an extended position and a stabilizer in a collapsed position;

[0027] Figure 10D is a perspective view of part 10D shown in Figure 10A;

[0028] Figure 11A is an exploded perspective view of the stair portion illustrated in Figure 10A with the first and second columns hidden from view to show certain internal details;

[0029] Figure 11B is a front cross-sectional view of the stair portion shown in Figure 10B, with the cross-section taken along plane 3B-3B;

[0030] Figure 12 is a perspective view showing a first stabilizing housing and first and second air dampers with stabilizers shown in a collapsed state according to one embodiment;

[0031] Figure 13 is a perspective view showing the stabilizers of Figure 12 shown in an extended state;

[0032] Figure 14 is a perspective view of a stabilizer according to one embodiment;

[0033] Figure 15A is a right side view of the stabilizer in Figure 14 with the caps removed to illustrate the internal detail;

[0034] Figure 15B is a right-side cross-sectional view of a portion of Figure 10B taken along plane 15B-15B;

[0035] Figure 16 is an exploded perspective view of the stabilizer in Figure 14 shown together with a connector;

[0036] Figure 17 is an exploded close-up view of part 17 shown in Figure 10B;

[0037] Figure 18 is a front view of an air damper according to one embodiment; and

[0038] Figure 19 is a perspective view of the air damper in Figure 18. Detailed description

[0039] The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides some practical illustrations for implementing illustrative embodiments of the present invention. Examples of constructions, materials, dimensions, and manufacturing processes are provided for selected elements, and all other elements employ what is known to those skilled in the art in the field of the invention. Those skilled in the art will recognize that many of the examples given have a variety of suitable alternatives.

[0040] Figure 1A is a front perspective view of a ladder 10 according to some embodiments. Figures 1B, 2A, and 2B are front perspective views of a ladder 10 unfolded from its folded position illustrated in Figure 1 and locked at various angles, according to some embodiments. In Figure 1B, the ladder 10 has been unfolded from its folded position in Figure 1A and locked at an angle of approximately 30 degrees. In Figures 2A and 2B, the ladder 10 has been locked at an angle of approximately 180 degrees. In Figure 2A, an upper portion 12 of the ladder 10 is in a collapsed / retracted state, while in Figure 2B, the upper portion 12 of the ladder 10 is in an extended state.The staircase 10 illustrated in these views may have a first staircase section 14 and a second staircase section 16, each of which includes two opposing uprights, a left-side upright 18 and a right-side upright 20, each formed by a plurality of columns 22. According to the illustrated embodiment, each opposing column of each upright includes a rung 24 extending between them, wherein each rung 24 is coupled at each end to an opposing column by means of a connector unit 28. In some embodiments, the columns 22 are made of aluminum. Other materials are contemplated and are within the scope of the invention.The columns 22 are illustrated with a circular cross-section (when viewed along the longitudinal axis 40 of the columns 22). The columns 22 may have a rectangular cross-section as illustrated in patent publication US-2012 / 0267197 Al assigned to the assignee of the immediate application. Other cross-sections are also contemplated (e.g., square, oval, or polygonal shapes). As will be described herein, in some embodiments, the columns 22 may be substantially hollow to allow a connector unit 28 to fix the step 24 to a column on each of the uprights 20, 18 on the right and left sides.

[0041] Figure 2C illustrates a close-up perspective view of a rung 24 of the first part 14 of the ladder. Figure 2D illustrates a side view showing a rung 24 of the first part 14 of the ladder and a rung 24 of the second part 16 of the ladder when the ladder 10 is folded as shown in Figure 14. In some embodiments, each rung 24 comprises a first flat surface 30 and a second flat surface 32 opposite the first flat surface 30. The first surface 30 of each rung 24 of the first part 14 of the ladder defines a flat bearing surface 34. At least one of the first and second flat surfaces of the second part 16 of the ladder defines a flat bearing surface 34.Referring again to Figures 2A-2B, when the ladder 10 is unfolded for use, the first surface 30 of each rung 24 of the second part 16 of the ladder has a flat bearing surface 34, as shown in the close-up view of Figure 2C. However, when the ladder 10 is folded for storage or unfolded at angles other than approximately 180 degrees (e.g., as shown in Figure 1B), the first surface 30 of each rung 24 of the second part 16 of the ladder may not be oriented upwards, and therefore the flat bearing surface 34 may be defined on the underside of the rung 24 when the ladder 10 is folded for storage or unfolded at angles other than 180 degrees.The flat bearing surface 34 of each rung 24 of the first and second parts 14, 16 of the ladder may have bands 36 defined thereon to provide friction between the flat bearing surface 34 and the contact surface of a user (e.g., the soles of the user's shoes). As will be described herein, the rungs may be substantially hollow to allow a connector unit 28 to fix the rung 24 to a post on each of the right-side stile 20 and the left-side stile 18. The rungs may be extruded from aluminum, although other materials and manufacturing methods may also be used.

[0042] Although Figures 2C and 2D illustrate a step 24 with a substantially rectangular cross-section, other cross-sectional shapes of the step 24 are also contemplated. For example, the step 24 may have a parallelogram cross-section such as those illustrated in patent publication US-2012 / 0267197 A1, assigned to the assignee of the immediate application. Although Figures 2C and 2D illustrate a substantially rectangular step 24, at least a portion of the first surface 30 of the first and second parts 14, 16 of the ladder forms an angle 60 with respect to a horizontal plane 42. In the illustrated embodiment, when the angled portions of the first surface 30 form an angle with respect to the horizontal plane 42, the angle may be between approximately 5 degrees and 45 degrees (e.g., between 5 degrees and 20 degrees).Such embodiments allow at least the angled portion 38 of the first surface 30 of the ladder 10 to be horizontal when the ladder 10 is turned towards a vertical wall (e.g., leaning against a wall at an angle), so that during normal use, at least a portion of the vertical wall can be nearly horizontal. However, depending on the angle at which the ladder 10 is leaning against a vertical wall, the angled portion 38 may be further from, or not horizontal at all.

[0043] Returning to Figure 2C, each rung 24 is connected to a column of the plurality of columns 22 by means of a connector unit 28. In some cases, the plurality of columns 22 is arranged in a nested arrangement for relative axial movement in a telescopic form such that the ladder 10 is extendable or foldable along the longitudinal axis 40 of the columns 22. Such telescopic ladders and various types of connector units are described in detail in US Patent 8,387,753 B2 and US Patent 6,883,645 B2, both assigned to the assignee of the immediate application.In such telescopic ladders, the connector unit 28 includes a release button 43 that can be slid along a front surface 44 of the rung 24 to selectively unlock or lock relative axial movement between two adjacent columns 22 of the plurality of columns 22, the front surface 44 of the rung 24 generally being perpendicular to a plane 46 normal to the longitudinal axis 40 of the plurality of columns 22.

[0044] Figure 2E illustrates a sectional top view of a stair portion according to some embodiments, taken along a plane parallel to the top surface of a tread, illustrating details of connector unit 28. The sectional view in Figure 2E is representative of all stair treads with connector unit 28. The connector unit comprises a collar portion 28a surrounding the columns 22 and in contact with the perimeter surface of an outer column, and a rung portion 28b inserted into a rung 24. In the embodiment shown in Figure 2E, the connector unit 28 includes a latching mechanism housed in the rung portion 28b comprising two release buttons 43a and 43b and a pin 45. The release button 43a can be slid along the front surface 44 of the rung, and the release button 43b can be slid along the rear surface 47 of the rung 24.In the embodiment of Figure 2E, the pin 45 is arranged in an extended position, extending into an opening 29 defined on the connector unit 28 and into the openings 41 of the columns 22. In some embodiments of the present invention, the pin 45 is deflected (e.g., by the spring 49) to assume the extended position. When this is the case, the pin 45 can be selectively pushed into a retracted position by sliding the button 43a or button 43b in a direction 51. According to the illustrated embodiment, the pin 45 includes one or more through holes 53 through which the stems 55 of each button 43a, 43b can be inserted (e.g., by means of a friction fit) to engage the buttons 43a, 43b to the pin 45 in a cooperative manner.As shown in Figure 2E, pin 45 can be retracted or extended by sliding button 43a or button 43b along the respective surface 44 or 47 in direction 51, as illustrated. The sliding motion of either button would also slide the other button in direction 51 due to their cooperative connection via pin 45. In some cases, each rung 24 of the first ladder part 14 and the second ladder part 16 may have a sliding button on the front surface 44 and a sliding button on the rear surface 47, as illustrated. Alternatively, any ladder part (first ladder part 14 or second ladder part 16) may have buttons on both the front surface 44 and the rear surface 47.

[0045] Referring back to Figure 1A, the folding ladder 10 comprises a pair of hinge mechanisms that articulately connect the first ladder section 14 to the second ladder section 16. Figure 3 illustrates a perspective view of a hinge mechanism 48, and Figures 4A-4B illustrate various detailed views of the hinge mechanism 48 according to certain embodiments of the invention. As seen in Figures 1A-2B and Figure 3, the hinge mechanism 48 can fold the first and second ladder sections 14, 16 around a hinge axis 50. The hinge mechanism 48 can lock the first and second ladder sections 14, 16 such that the first ladder section 14 and the second ladder section 16 form an angle 60 with each other.As best seen in Figure 1B, angle 60 can be defined as the angle between the longitudinal axis 40 of columns 22 of the first part 14 of the staircase and the longitudinal axis 40 of columns 22 of the second part 16 of the staircase. In Figure 1A, the first and second parts 14, 16 of the staircase form an angle 60 of approximately 0 degrees. In Figure 1B, the first and second parts 14, 16 of the staircase form an angle 60 of approximately 30 degrees. In Figures 2A-2B, the first and second parts 14, 16 of the staircase form an angle 60 of approximately 180 degrees.

[0046] Referring now to Figures 4A-4C, each hinge mechanism 48 comprises a first hinge element 52 that can be connected to the first ladder part 14 and a second hinge element 54 connectable to the second ladder part 16. As shown in Figure 1B, the first hinge element 52 can be connected coaxially with the longitudinal axis 40 of the columns 22 of the first ladder part 14, and the second hinge element 54 can be connected coaxially with the longitudinal axis 40 of the columns 22 of the second ladder part 16.For example, as shown in Figure 1A, the first hinge elements 52 of the left and right side hinge mechanisms are both connected to the upper columns 56 (left and right side columns 56) of the first stair section 14, and the second hinge elements 54 of the left and right side hinge mechanisms are connected to the upper columns 58 (left and right side columns 58) of the second stair section 16. The hinge mechanisms on the left and right sides shown in Figure 1A may be substantially similar. Alternatively, the hinge mechanism 48 on the right side may be a mirror image of the hinge mechanism 48 on the left side. The first and second hinge elements 52, 54 may rotate relative to each other about the hinge axis 50.When the first and second hinge elements 52, 54 are rigidly coupled to the first and second ladder parts 14, 16, rotation of the first and second hinge elements 52, 54 rotates the first and second ladder parts 14, 16 relative to each other and vice versa. The rotation of the first and second ladder parts 14, 16 is about the hinge axis 50, such that the first and second ladder parts 14, 16 and the first and second hinge elements 52, 54, when rotated, form an angle 60 with each other. At least a portion of an edge 62 of the second hinge element 54 may be semicircular. Additionally, at least a portion of an edge 64 of the first hinge element 52 may be semicircular. Other shapes of the edge portions 62, 64, such as semi-elliptical or other arched shapes, are also contemplated.

[0047] Continuing with reference to Figures 3 and 4A-4C, the hinge mechanism 48 comprises a shifting mechanism 70. The shifting mechanism 70 can act as a selector and allow a user to select the angle 60 between the first and second ladder parts 14, 16. The shifting mechanism 70 comprises a shifting pattern 72 defined by a plurality of slots 74, 76, 78 positioned peripherally on the first hinge element 52. Each slot 74, 76, 78 corresponds to an angular position of the first ladder part 14 with respect to the second ladder part 16, and adjacent slots 74, 76, 78 are separated by a distance 80 defined along a perimeter of the first hinge element 52.As best seen in Figure 4A, a selector pin 82 can be moved according to the shift pattern 72 and received by a groove 74, 76, 78 at a first end 84 of the groove 74, 76, 78 to lock the second ladder part 16 in an angular position with respect to the first ladder part 14. In the illustrated embodiments shown in Figures 4A and 4B, the shifting mechanisms comprise three grooves 74, 76, 78 corresponding to three angular positions in which the first and second ladder parts 14, 16 can be placed. As shown in Figure 4C, the selector pin 82 can be released from the first end 84 and moved proximally to the second end 86 to release the first and second ladder parts 14, 16 from their locked position. Once released, the first and second parts 14, 16 of the ladder can be rotated relative to each other to change the angle 60 between them.

[0048] As shown in Figures 4A-4C, the hinge mechanism 48 includes one or more safety indicators. The safety indicators may be a visual indicator, such as color-coded markings or bands, to indicate whether the first and second ladder parts 14, 16 are locked in an angular position. The safety indicators may be an audible "click" or a tactile indicator to provide auditory or tactile feedback to the user and indicate that the first and second ladder parts 14, 16 are securely locked in an angular position. In the embodiments illustrated in Figure 4A, the safety indicators provide a first visual indication 90 (e.g., a green stripe or zone or other distinctive markings in a first region 96) when the first and second ladder parts 14, 16 are locked in an angular position.In the embodiment illustrated in Figures 4B and 4C, the safety indicators provide a second visual indication 92 (e.g., a red stripe or zone or other distinctive markings placed in a second region 98) when the first and second ladder parts 14, 16 are unlocked. Additionally, the ladder 10 may include other distinctive markings (e.g., alphanumeric characters, images, symbols, etc.) to indicate the predetermined angles at which the first and second ladder parts 14, 16 can be positioned. For example, in the embodiment illustrated in Figure 4B, the three distinctive markings 94 are symbolic representations of the angular positions of the ladder 10, indicating that the first and second ladder parts 14, 16 can be locked at approximately 0 degrees, approximately 30 degrees, and approximately 180 degrees.Such distinctive markings 94 can also be placed proximal to each slot 74, 76, 78 to provide the user with information about the angle 60 of rotation at which the first and second ladder parts 14, 16 should be turned when the selector pin 82 is placed close to (e.g., at or near the second end 86 of) each slot 74, 76, 78.

[0049] Referring now to Figure 5, in embodiments, the hinge mechanism 48 comprises a locking plate 100 positioned on the second hinge element 54 such that a center 110 of the locking plate 100 is concentric with the hinge axis 50. As seen in the cross-sectional view of Figure 5, the locking plate 100 can be screwed to the second hinge element 54 such that the hinge axis 50 coincides with the center 110 of the locking plate 100. Alternatively, the locking plate 100 can be connected to the second hinge element 54 such that it forms a friction fit with the inner surfaces (e.g., ribs) of the second hinge element 54 such that the center 110 of the locking plate 100 is concentric with the hinge axis 50.When coupled in this way, the locking plate 100 is fixedly placed on the second hinge element 54 and does not move or rotate with respect to the second hinge element 54.

[0050] Continuing with reference to Figure 5, the locking plate 100 comprises a plurality of recesses 112, 114, 116. Each recess extends radially inward from an outer edge 118 of the locking plate 100 and toward the center 110 of the locking plate 100. Therefore, each of the recesses 112, 114, 116 is directed radially inward toward the hinge axis 50 from one end of the second hinge element 54 due to the concentric position of the center 110 of the locking plate 100 and the hinge axis 50. Recesses 112, 114, 116 are angularly spaced around the hinge axis 50 such that the angular position of each recess around the hinge axis 50 corresponds to a predetermined angle 60 between the first and second ladder parts 14, 16. In this position, the selector pin 84 is received in a groove 74, 76, 78.For example, in an illustrative embodiment, each rebate may be separated from another rebate by an angle 119 corresponding to the angle 60 between the first and second ladder parts 14, 16. In such cases, the number of rebates 112, 114, 116 corresponds to the number of positions in which the first and second ladder parts 14, 16 can be locked. In the illustrated embodiment, the locking plate 100 includes three recesses 112, 114, 116: a first recess 112, a second recess 114, and a third recess 116. Therefore, the first and second ladder parts 14, 16 can be locked in three angular positions, corresponding to an angle 119 between each of the recesses 112, 114, 116. In operation, the first and second ladder parts 14, 16 can be rotated through an angle 60 corresponding to the angle 119 between any two recesses (e.g., 112 and 114, or 112 and 116) and locked in those positions.As described above, the angle 60 between the first and second ladder parts 14, 16 can be between approximately 0 degrees and approximately 180 degrees. For example, the locking plate 100 in the illustrated embodiment includes three recesses 112, 114, 116, and the first and second ladder parts 14, 16 can be locked in a first angular position, a second angular position, and a third angular position at angles of approximately 0 degrees, approximately 30 degrees, and approximately 180 degrees, respectively. Consequently, in the illustrated embodiments shown in Figure 5, the angle 119 between the first recess 112 and the second recess 114 is approximately 30 degrees, and the angle 119 between the first recess 112 and the third recess 116 is approximately 180 degrees. Additional recesses are also contemplated corresponding to additional lockable configurations of the first and second parts 14, 16 of the staircase (e.g., at approximately 45 degrees, approximately 60 degrees, approximately 120 degrees or other additional angles).

[0051] Referring now to Figure 6, in embodiments, the folding ladder 10 comprises a locking pin 120 connected to the selector pin 82. The locking pin 120 has an elongated body arranged around a central axis 122 of the locking pin 120. As illustrated in Figure 6, the locking pin 120 moves in one direction along its central axis 122 to enter and exit a recess (112, 114, 116) and can be received by a recess (112, 114, 116) of the locking plate 100. For example, the locking pin 120 is received by a first recess 112 to lock the first and second angle parts at a first angle 60 (e.g., 0 degrees), in a second recess 114 to lock the first and second angle parts at a second angle 60 (e.g., 30 degrees), and in a third recess 116 to lock the first and second angle parts at a third angle 60 (e.g., 180 degrees).As described above, the locking plate 100 can have any number of recesses 112, 114, 116, and consequently, the first and second ladder parts 14, 16 can be locked in the corresponding number of angular positions. Referring back to Figure 5, the locking pin 120 is received in the second recess 114. Consequently, the selector pin 82 is received in the second slot 76. The angle between the first and second ladder parts is approximately 30 degrees in the embodiment illustrated in Figure 5. Other angular positions are contemplated. For example, when the first and second ladder parts are locked at an angle of approximately 0 degrees, the locking pin 120 is received fully in the first recess 112, and the selector pin 82 is received fully in slot 74.When the first and second ladder parts are locked at an angle of approximately 180 degrees, the locking pin 120 is fully received in the third recess 116 and the selector pin 82 is fully received in the slot 78.

[0052] As shown in Figures 6 and 7, the locking pin 120 has a rectangular cross-section with a longitudinal edge 121 and a transverse edge 123, although any non-circular cross-section is also acceptable. The locking pin 120 can be mounted on the first hinge element 52 to move along its central axis 122 radially away from and toward the hinge axis 50. As will be described later, the locking pin 120 is deflected radially by a deflection spring 124 toward the hinge axis 50. The locking pin 120 rotates about its central axis 122 such that the shape of the locking pin 120's cross-section aligns with the shape of a recess (112, 114, 116) in the locking plate 100.

[0053] Continuing with reference to the embodiments illustrated in Figures 6 and 7, the locking pin 120 has an opening 126 in which the selector pin 82 is received. Therefore, the locking pin 120 and the selector pin 82 are coupled so that they move cooperatively, as will be described below. In some embodiments, the locking pin 120 and the selector pin 82 are coupled such that the center axis 122 of the locking pin 120 is located transversely at an angle of 60 (e.g., 90 degrees) with respect to the axis 128 of the selector pin 82. Other angles between the axis of the locking pin 120 and the selector pin 82 are also contemplated.Returning to Figure 5 and continuing with reference to Figure 6, the selector pin 82 and the locking pin 120 are coupled to each other such that the locking pin 120 engages a recess (112, 114, 116) in the locking pin 120 when the selector pin 82 moves into a slot 74, 76, 78 of the shift pattern 72. Additionally, the coupling between the selector pin 82 and the locking pin 120 is such that the locking pin 120 moves away from a recess (112, 114, 116) in the locking plate 100 when the selector pin 82 moves away from a slot 74, 76, 78 of the shift pattern 72. While Figures 5 and 6 illustrate the locking pin 120 in a position where it is received by a recess (112, 114, 116) in the locking plate 100, Figure 7 illustrates the locking pin 120 in a position where it is retracted away from the recess in the locking plate 100.As shown in Figure 7, the locking pin 120 can be deflected radially by the deflection spring 124 toward the hinge axis 50. When fully retracted away from the recess in the locking plate 100, the locking pin 120 can rest against a seat 130 when it is retracted away from a recess (112, 114, 116) in the locking plate 100. As described above, the first ladder part 14 and the second ladder part 16 can rotate relative to each other about the hinge axis 50. Rotation of the first ladder part 14 and the second ladder part 16 relative to each other can position the locking pin 120 proximal to a recess (e.g., in a ladder-angled opening 132).Once the angle 60 between the first and second ladder parts 14, 16 is adjusted to correspond to the angle 119 between any two of the recesses (112, 114, 116) of the locking plate 100, the locking pin 120 is brought close to a recess (112, 114, 116) and extended into the recess due to the spring action of a spring housed in the seat 130.

[0054] As described above, the coupling between the locking pin 120 and the selector pin 82 allows the locking pin 120 to be fully received in a recess (e.g., the second recess 114 shown in Figure 5) to lock the first ladder part 14 and the second ladder part 16 in an angular position and to be fully retracted from a recess (112, 114, 116) to release the first and second ladder parts 14, 16 from an angular position. When the locking pin 120 is fully received in the recess, the entire length of the recess is occupied by at least one first end 134 of the locking pin 120, as shown in Figures 5 and 6. In this position, the selector pin 82 is received in a slot 74, 76, 78 (e.g., the second slot 76 as shown in Figure 5) such that the selector pin 82 rests on the first end 84 of the slot 74, 76, 78.In the fully engaged position, the first and second ladder parts 14, 16 are locked to each other, and an angle of 60° between them is fixed. When the locking pin 120 is fully released from the recess (e.g., the second recess 114, as shown in Figure 7), a second end 136 of the locking pin 120 seats against the seat 130. In the fully released position, the first end 134 of the locking pin 120 is almost completely retracted from the recess. Consequently, the selector pin 82 moves toward the second end 86 of the slot 74, 76, 78 (e.g., the second slot 76 is best seen in Figure 5). In the fully released position, the first and second ladder parts 14, 16 are rotatable, and the angle of 60° between them can be changed. Before changing the angle 60 between the first and second ladder parts 14, 16, the selector pin 82 can be placed close to another slot 74, 76, 78 (e.g., the first slot 74 or the third slot 78 shown in figure 5). When the first and second ladder parts 14, 16 are rotated to a desired angular position, the locking pin 120 is received by another recess (e.g., the first or third recess 112, 116) and the selector pin 82 is received by the first end 84 of another slot 74, 76, 78 (e.g., the first or third slot 78).

[0055] Referring now to Figures 8A and 8B, the locking pin 120 can be shaped and oriented such that the locking pin 120 abuts the edge 62 of the second hinge element 54 when the first and second ladder parts 14, 16 are angled at any angle 60 other than a plurality of predetermined angles. As seen from the close-up view of Figure 8B, each rebate has a corresponding ladder-angled opening 132 defined on the edge 62 of the second hinge element 54. Each ladder-angled opening 132 has an opening shape. The opening shape may allow the insertion of the locking pin 120 through it when the locking pin 120 is rotated about its central axis 122 to a rotation where the orientation of the cross-section of the locking pin 120 generally matches the opening shape (e.g., as shown in Figures 5 and 6).As shown in Figures 8A and 8B, the opening shape of a ladder-angled opening 132 can prevent the insertion of the locking pin 120 through it when the locking pin 120 rotates about its central axis 122 to a point where the orientation of the locking pin 120's cross-section no longer matches the opening shape. As shown in Figures 8A and 8B, the longitudinal edge 121 and the transverse edge 123 do not match the opening shape of the ladder-angled opening 132 of the recess 112, thereby preventing the locking pin 120 from entering the recess 112. In the illustrated embodiment, each recess is arranged radially inward along a radial line 138 toward the hinge axis 50. When the locking plate 100 is placed concentrically with the hinge axis 50, the center 110 of the locking plate coincides with the intersection point of the radial lines 138.Recesses 112, 114, 116 are rectangular, and the ladder-angled opening shapes allow passage of the locking pin 120 which has a rectangular cross-section oriented such that the center axis 122 of the locking pin 120 is in line with a radial line 138 of the recess, and the locking pin 120 rotates about its center axis 122 such that the cross-section of the locking pin 120 aligns with the opening shape of the ladder-angled opening 132.

[0056] Referring again to Figures 5 and 6, the locking pin 120 can be rotated about its central axis 122 by means of a selection collar 142. As described above, each recess has a ladder-angled opening 132 that allows the locking pin 120 to pass through it when the locking pin 120 is rotated about its central axis 122 to match the shape of the opening. In such cases, the ladder-angle selector allows manual selection of the desired angle 60 between the first and second ladder parts 14, 16. In some embodiments, the ladder-angle selector is a selection collar 142 that is slidably engaged with the first hinge element 52. The selection collar 142 is rigidly engaged with the selector pin 82.In turn, the selector pin 82 is rigidly coupled with the locking pin 120, thereby allowing the selector collar 142 to manipulate the movement and rotation of the locking pin 120. For example, as shown in Figure 5, the selector collar 142 can slide against the first hinge element 52 along a collar axis 144 in a direction illustrated by the arrow "d," generally defined as parallel to the collar axis 144 and the center axis 122 of the locking pin 120. As the selector collar 142 slides along direction "d," the selector pin 82 moves along with the selector collar 142 and exits the second slot 76 in direction "d" toward the second end 86 of the second slot 76 (best illustrated in Figure 4C).In turn, referring again to figure 5, the locking pin 120 moves along the "d" direction parallel to its central axis 122, and radially outwards from the second recess 114. When the selector pin 82 rests against the second end 86 of the second groove 76, the second end 136 of the locking pin 120 abuts the seat 130 (better seen in figure 7).

[0057] Referring back to Figures 4A-4C and 5, when the selection collar 142 is moved in direction "d" such that the selector pin 82 moves toward the second end 86 of the second slot 76, the first and second ladder parts 14, 16 are not locked in an angular position. Consequently, as described above, the second region 98, previously hidden under the selection collar 142 when the first and second ladder parts 14, 16 were locked, becomes visible to the user to indicate that the first and second ladder parts 14, 16 are not securely locked. Once the angle 60 between the first and second ladder parts 14, 16 is adjusted to the desired angle, the locking pin 120 moves in direction "f" because it is spring-deflected toward the hinge axis 50. Direction "d" can be opposite to direction "f".The selector pin 82 moves along the "f" direction and is proximal to the first end 84 of the second groove 76. During this movement, the selector collar 142 also moves along the "f" direction due to the rigid coupling between the selector collar 142, the locking pin 120, and the selector pin 82. The locking pin 120 is received in a recess (112, 114, or 116), and the selector pin 82 is received in a groove 74, 76, or 78, thereby preventing any relative rotational movement about the hinge axis 50 between the first and second hinge elements 52 and 54 and the first and second ladder parts 14 and 16 connected thereto.As the selection collar 142 moves along the "f" direction, the first region 96, previously hidden under the selection collar 142 when the first and second ladder parts 14, 16 were unlocked, becomes visible to the user to indicate that the first and second ladder parts 14, 16 are securely locked.

[0058] Continuing with reference to Figures 4A-4C and Figure 5, the selection collar 142 can rotate about the collar axis 144 with respect to the first hinge element 52. When the selection collar 142 rotates (e.g., along the "e" direction about the collar axis 144 illustrated in Figure 5), the selector pin 82 moves along the shift pattern 72 defined in the first hinge element 52. For example, the selection collar 142 can be moved until the selection pin moves adjacent to the third slot 78. When the selection collar 142 rotates about the collar axis 144 with respect to the first hinge element 52, the rigid coupling between the selection pin 82 and the locking pin 120 transmits the rotational motion of the selection collar 142 and rotates the locking pin 120 about its central axis 122.When the selection collar 142 is rotated sufficiently to position the selector pin 82 proximal to the third groove 78 (e.g., at the second end 86 of the third groove 78), the locking pin 120 rotates about its central axis 122 such that its cross-section matches the opening shape of the third recess 116. Such manual manipulation may allow the user to manually select the desired angle 60 from among a plurality of predetermined angles between the first and second ladder parts 14, 16.

[0059] In use, a user can unfold a ladder 10 from its angular position during storage (e.g., the first and second ladder parts 14, 16 form an angle 60 of approximately 0 degrees, as illustrated in Figure 1A). Referring to Figures 4A-4C, the user can move the selection collar 142 along a direction "d" and rotate the selection collar 142 in a direction "e" until the selection pin is close to the second end 86 of another slot 74, 76, 78. The rotational movement of the selection collar 142 rotates the locking pin 120 about its central axis 122 such that the cross-section of the locking pin 120 coincides with a ladder-angled opening 132 of a recess (112, 114, 116).The user can then rotate the first and second ladder parts 14, 16 relative to each other to the desired angle 60° (chosen from predetermined angles at which the first and second ladder parts 14, 16 can be locked). Once the desired angle 60° is reached, the locking pin 120 is automatically pushed into a recess (112, 114, or 116) because the locking pin 120 is spring-loaded toward the hinge axis 50 along direction "f". The selector pin 82 and the selector collar 142 also move along direction "f". The first and second ladder parts 14, 16 are locked in the desired angular position, and the selector pin 82 rests on the first end 84 of a groove 74, 76, 78 corresponding to the desired angular position.The first and second ladder parts 14, 16 cannot be turned further until the locking pin 120 is released from the recess (112, 114 or 116) by moving the selection collar 142 along the "d" direction and repeating the steps described above.

[0060] The embodiments of the folding ladder described herein allow the user to fold the ladder for storage to minimize space occupied and to unfold and lock it securely at a plurality of angles. The embodiments of the folding ladder described herein are safe and easy to use.

[0061] Figure 9A is a front perspective view of a ladder 210 according to some embodiments. Figures 9B-9D are front perspective views of a ladder 210 unfolded from its folded position illustrated in Figure 9A and locked at various angles, according to some embodiments. In Figures 9B and 9C, the ladder 210 has been unfolded from its folded position in Figure 9A and locked at an angle of approximately 180 degrees. In Figure 9D, the ladder 210 has been unlocked at an angle of approximately 30 degrees. In Figure 9B, an upper portion 222 of the ladder 210 is in a collapsed state, while in Figure 9C, the upper portion 222 of the ladder 210 is in an extended state.

[0062] Referring now to Figure 9A, the telescopic ladder 210 comprises a first upright 214 and a second upright 216 (e.g., the left and right uprights illustrated in Figure 9A). The first and second uprights each have a plurality of columns 218 arranged in a nested configuration for relative axial movement in a telescopic manner along an axis 220 of the plurality of columns 218 between an extended position and a collapsed position. For example, in Figure 9A, a top portion 222 of the ladder 210 is shown in a collapsed position where the columns 218 are nested within each other along the axis 220 of the columns 218 in a telescopic manner, and in Figure 9D, the top portion 222 of the ladder 210 is shown in an extended position.

[0063] As shown in Figure 9A, the ladder 210 comprises a plurality of rungs 224 extending between the first upright 214 and the second upright 216. Each rung 224 can be connected to a column 218 of the first upright 214 and to a column 218 of the second upright 216. As shown in Figure 9A, each rung 224 can be connected to the columns 218 by means of a connector unit 226. Continuing with reference to Figure 9A, in some cases, each rung 224 comprises a first flat surface 228 and a second flat surface 230 opposite the first flat surface 228. The first surface 228 of each rung 224 of the first ladder portion 250 defines a flat bearing surface 232. At least one of the first and second flat surfaces 228, 230 of the second part 254 of the staircase defines a flat support surface 232.Referring to Figures 9B and 9C, when the ladder 210 is extended for use, the first surface 228 of each rung 224 of the second part 254 of the ladder has a flat bearing surface. However, when the ladder 210 is folded for storage or extended at angles other than approximately 180 degrees (e.g., as shown in Figure 9A or 9D), the first surface 228 of each rung 224 of the second part 254 of the ladder may not face upwards, and therefore the flat bearing surface 232 may be defined on the underside of the rung 224 when the rung 224 is folded for storage or extended at angles other than 180 degrees.The flat bearing surface 232 of each rung 224 of the first and second parts 250, 254 of the ladder may have defined bands 234 thereon to provide friction between the flat bearing surface and the contact surface of a user (e.g., the soles of the user's shoes). As will be described herein, the rungs 224 may be substantially hollow to allow a connector unit 226 to attach the rung 224 to a column 218 on each of the right and left uprights. The rungs 224 may be extruded from aluminum, although other materials and manufacturing methods may also be used.

[0064] Although Figures 9A-9D illustrate a step 224 with a substantially rectangular cross-section, other cross-sectional shapes of the step 224 are also contemplated. For example, the step 224 may have a parallelogram cross-section such as those illustrated in patent publication US-2012 / 0267197 A1, assigned to the assignee of the immediate application. Although Figures 9A-9D illustrate a substantially rectangular step 224, as best seen in Figure 10D, at least a portion 238 of the first surface 228 of the first and second parts 250, 254 of the step may form an angle with respect to a horizontal plane 242. In the illustrated embodiment, when the angled portion 238 of the first surface 228 forms an angle with respect to a horizontal plane (not shown). The angled part 238 can form an angle between approximately 5 degrees and 45 degrees (e.g.between 5 degrees and 20 degrees) with respect to the horizontal plane 242. Such embodiments allow at least the angled portion 238 of the first surface 228 of the rung 224 to be horizontal when the ladder 210 is turned towards a vertical wall (e.g., leaning against a wall at an angle) so that during normal use, at least a portion 238 of the rung 224 can be nearly horizontal. However, depending on the angle at which the ladder 210 is leaning against a vertical wall, the angled portion 238 may be further from or not horizontal.

[0065] In some embodiments, the columns 218 are made of aluminum. Other materials are contemplated and are within the scope of the invention. The columns 218 are illustrated as having a circular cross-section (when viewed along the axis 220 of the columns 218). However, the columns 218 may have a rectangular cross-section as illustrated in patent publication US-2012 / 0267197 A1 assigned to the assignee of the immediate application. Other cross-sections are also contemplated (e.g., square, oval, or polygonal shapes). The columns 218 may be substantially hollow to receive another column 218 from above. Additionally, the steps 224 may be substantially hollow, such that a pair of latch units (not shown) can be housed in the hollow step 224.

[0066] As described above, the rungs 224 are connected to the columns 218 by a plurality of connector units 226. The connector units 226 may have latch units housed in the hollow portion of each rung 224 to unlock or selectively lock relative axial movement between adjacent columns 218. Such connector units 226 are described in US Patent 8,387,753 B2 and US Patent 6,883,645, both of which were assigned to the assignee of the immediate application. Each latch unit has a release button 246 that can be manually actuated to unlock the selectively locked relative axial movement between two adjacent columns 218. In the embodiment shown in Figure 9A, the release buttons can be slid inwards along a front surface 248 of the step 224 (e.g., with the user's thumbs), to unlock their respective latch units.Therefore, when the release buttons on the right and left sides of step 224 are pressed, the adjacent columns 218 are allowed to move axially. Gravity may cause these columns 218 and their step 224 to fold down into a position similar to the steps 224 shown in the collapsed portion of ladder 210 depicted in Figure 9A.

[0067] In some cases, the ladder 210 may comprise a first ladder part 250 and a second ladder part 254 that are joined together in a hinged manner. For example, the ladder 210 is foldable such that the first and second ladder parts 250, 254 form a first angle 258 with each other. The first angle 258 may be equal to between approximately zero degrees and approximately 180 degrees. In Figure 9A, the first angle 258 is approximately zero degrees. In Figures 9B and 9C, the first angle 258 is approximately 180 degrees. In Figure 9D, the first angle 258 is approximately 30 degrees. Each of the first and second stair parts 250, 254 may have a first upright 214 and a second upright 216 having a plurality of columns 218, and a plurality of steps 224 extending between the columns 218.The first and second parts 250, 254 of the ladder can be locked in various angular positions by means of hinge mechanisms known in the art. An illustrative hinge mechanism 260 is described and illustrated in codependent application US-14 / 557,944 entitled "Foldable ladder", assigned to the assignee of the immediate application, filed on December 2, 2014.

[0068] Referring now to Figures 10A and 10B, the first upright 214 comprises a first column 264 and the second upright 216 comprises a second column 268. The first and second columns 218 each have a hollow body. The first and second columns 218 can be connected to a first stabilizer housing 270. The first stabilizer housing 270 and the first and second columns 218 can be close to a floor surface 272 on which the ladder 210 is placed during use. The first stabilizer housing 270 and the first and second columns 218 can be coupled by means of a pair of connector units 226 as described above. Alternatively, a connector 274 can permanently connect the first and second columns 218 to the first stabilizer housing 270. The connector 274 can have a connector opening 276 (e.g.(as best illustrated in Figure 16) to receive the first housing 270 of the stabilizer. The connector 274 additionally receives the first and second columns 218 on an inner surface 278 thereof. The first and second columns 218 form a friction fit with the inner surface 278 of the connector 274.

[0069] Referring again to Figures 10A and 10B, the ladder 210 may include a first stabilizer 280 and a second stabilizer 282 connected to the first stabilizer housing 270. The first and second stabilizers 280, 282 may each be movable between an extended and a collapsed position. The first and second stabilizers 280, 282 may be substantially similar, although the right-side stabilizer 282 may be a mirror image of the left-side stabilizer 280 (around the axis 220 of the columns 218). The first and second stabilizers 280, 282 may slide relative to the first stabilizer housing 270. In some cases, the first and second stabilizers 280, 282 may be extended independently. For example, the first stabilizer 280 can be extended while the second stabilizer 282 is collapsed and vice versa, as illustrated in Figure 10C.As shown in Figures 10B and 10C, the first and second stabilizers 280, 282 can be folded into a hollow body portion 286 of the first stabilizer housing 270 in the collapsed position. In the extended position, the first and second stabilizers 280, 282 extend out of the hollow body portion 286 of the first stabilizer housing 270 beyond one of the first and second struts in a direction substantially normal to the axis 220 of the plurality of columns 218.

[0070] Referring now to Figures 11 A-11B and 12, the first stabilizer housing 270 has an opening 290 defined coaxially with the axis 220 of the plurality of columns 218. As shown in Figure 13, each of the first and second stabilizers 280, 282 has a locking button 294 that can protrude beyond the opening 290 defined on the first stabilizer housing 270 to lock the stabilizer 280, 282 in an extended position. The locking button 294 can generally be in a pressed position when the first and second stabilizers 280, 282 are collapsed and abut an inner surface 296 of the first stabilizer housing 270 and are close to a centerline 310 of the first stabilizer housing 270 through which the locking buttons can protrude when the first and second stabilizers 280, 282 are in a collapsed position.When the first and second stabilizers 280, 282 are extended to their extended position, the locking buttons remain pressed and abut an inner surface 296 of the first stabilizer housing 270. Upon encountering the opening 290, the locking buttons protrude beyond it, thereby locking the first and second stabilizers 280, 282 and preventing them from sliding relative to the first stabilizer housing 270. When the locking buttons protrude beyond the opening 290, they lock the stabilizers 280, 282 in the extended position. Such configurations can be used to improve the stability of the ladder 210 by shifting its center of gravity within the ladder's contact surface.

[0071] Referring again to Figure 11A-11B, each of the first and second columns 218 has a flange 320 positioned in the hollow body of the first and second columns 218 coaxially with the axis 220 of the plurality of columns 218. Figure 12 illustrates a close-up perspective view of the flanges of the first and second columns 218 (not shown in Figure 12). As shown in Figures 11A-11B and 12, the flange 320 of the first and second columns 218 can press the locking button 294 away from the opening 290, thereby releasing the first and second stabilizers 280, 282 from their locked position. As a result, the first and second stabilizers 280, 282 generally move inwards into the hollow body portion 286 of the first stabilizer housing 270. The flanges can be positioned and oriented on the first and second columns 218 such that when one column (e.g.The column 370 or column 380 shown in Figure 10A) above each of the first and second columns 264, 268 nests therein, the flanges are pushed in one direction towards the first stabilizer housing 270 (e.g., from a distance "a" shown in Figure 19B to a distance "b"). Referring to Figure 11A-11B, the edge 320 abuts the locking button 294 which protrudes beyond the opening 290 of the first stabilizer housing 270 due to the telescopic movement of the first column 264 towards the first stabilizer housing 270, the locking button 294 is pushed away from the opening 290, thereby unlocking the first stabilizer 280 from its extended position and moving it to a collapsed position.

[0072] Figure 14 is a perspective view of a stabilizer 280, 282 according to one embodiment of the invention. Figure 15A is a side view of the stabilizer 280, 282 of Figure 14 with the end cap 330 removed. As seen in Figures 14 and 15A, the stabilizer 280, 282 has a generally hollow body portion with a length "L1" equal to approximately half the length of the first stabilizer housing 270, "L2". The first and second stabilizers 280, 282 shown in the above embodiments, for example, may have a length L1, and the first stabilizer housing 270 may have a length L2, allowing both the first and second stabilizers 280, 282 to abut each other when collapsed.The length of the stabilizer 280, 282 can be measured from a first end 332 of the stabilizer 280, 282 to the second end 334 and may not include the end cap 330 of the stabilizer 280, 282 or any other additional caps. Similarly, the length of the first stabilizer housing 270 can be an end-to-end length of the body portion of the first stabilizer housing 270. The stabilizer 280, 282 has a parallelogram cross-section to facilitate sliding coupling with the first stabilizer housing 270 (which also has a parallelogram cross-section as shown in Figure 15B). Referring again to Figures 14 and 15A, a first surface 340 of the stabilizer 280, 282 is generally flat, and a second surface 342 of the stabilizer 280, 282 has one or more recessed tracks 344.The first and second surfaces 340, 342 are generally parallel and opposite each other, forming an angle "A" with respect to the horizontal plane 242. When placed in the first stabilizer housing 270, the first surface 340 forms an upper surface, and the second surface 342 forms a lower surface 212. The stabilizer 280, 282 also has a third surface 346 and a fourth surface 348, which together form the parallelogram shape of the stabilizer 280, 282. As described above, other shapes of the stabilizer 280, 282 are also contemplated, corresponding to the shape of the first stabilizer housing 270 (e.g., rectangular). With reference to Figures 15A and 15B, a connecting element 350 connects the stabilizer 280, 282 to the hollow body portion 286 of the first stabilizer housing 270.For example, the connecting element 350 is a square-headed bolt or screw that rests on recessed portions of the stabilizer tracks 280, 282 and forms a friction fit with them. One or more ends of the connecting element 350 can rest against the inner surface 296 of the first stabilizer housing 270 and facilitate sliding movement of the stabilizer 280, 282 relative to the first stabilizer housing 270. As mentioned above, the locking button 294 extends beyond the first surface 340 of the stabilizer 280, 282 (e.g., outside the opening 290, which is best illustrated in Figure 16). The locking button 294 can be spring-deflected to protrude from the opening 352 of the stabilizer 280, 282, and consequently from the opening 290 of the first stabilizer housing 270, by means of a clamp 360.One end 364 of the clamp 360 is received by the second surface 342 of the stabilizer 280, 282 (e.g., through a groove, not illustrated), and an opposite end 362 of the clamp 360 is received by a groove 366 in the first surface 340 of the stabilizer 280, 282. The stabilizer 280, 282 may also have an end cap 330 having a cross-sectional area larger than the cross-sectional area of ​​the hollow body portion 286 of the first housing 270 of the stabilizer. Therefore, the end cap 330 does not collapse into the first housing 270 of the stabilizer when the stabilizer 280, 282 is collapsed. Such embodiments facilitate manual access to the stabilizer 280, 282 for extension from its collapsed position.In addition to the end cap 330, the stabilizer 280, 282 may have an additional cap 368 positioned close to the centerline 310 of the first stabilizer housing 270 and within the hollow body portion 286 of the first stabilizer housing 270.

[0073] As mentioned above, and referring now to Figure 17, the stabilizer locking buttons 280, 282 can be actuated by means of flanges placed on the first and second columns 218 due to the telescopic nesting movement of the plurality of columns 218 within the first and second columns 218 (not shown in Figure 17). Figure 17 illustrates a third column 370 located above the first column 264. Similarly, a fourth column 380 can be placed above the second column 268 (better seen in Figure 10A). Referring again to Figure 17, the third column 370 can be nested within and extend from the first column 264 along the axis 220 of the plurality of columns 218. In some cases, each column may include an air damper 200 positioned coaxially with the axis 220 of the column to limit the relative axial movement of the plurality of columns 218.In the illustrated embodiment, the air damper 200 covers a lower perimeter edge 210 of the third column 370 to restrict airflow through the third column 370. An illustrative air damper 200 is described in patent publication US-2012 / 0267197 A1 assigned to the immediate application assignee. As illustrated, the flange 320 can extend from a lower surface 412 of a first air damper 400 positioned within the first column 264 of the first upright 214. As seen in Figure 17, the first air damper 400 is coaxial with the locking button 294 of the first stabilizer 280 when the locking button 294 protrudes beyond the opening 290 of the first stabilizer housing 270 in an extended position.

[0074] Referring now to Figures 18 and 19, each of the air dampers 400 may have a tab 414 defined on a surface of its perimeter to facilitate insertion into the third column 370 and to prevent the removal of the air damper 400 from the third column 370. The tab 414 has a tapered leading edge 416 that facilitates engagement with a corresponding opening 418 in the third column 370, and a vertical trailing edge 420 that prevents the removal of the tapered tab 414 from the third column 370. The air damper 400 is engaged with the third column 370 such that the tabs of the air damper 400 protrude beyond the corresponding openings (better seen in Figure 19A) in the third column 370. The air damper 400 may be positioned such that the openings are close to the lower perimeter edge of the third column 370.The air damper 400 is coupled to the third column 370 so that the nesting movement of the third column 370 towards the first column 264 moves the flange 320 of the air damper 400 towards the opening 290 of the first housing 270 of the stabilizer. As the additional columns 218 descend towards the first column 264 from above, the air damper 400 moves even closer to the first stabilizer housing 270 until the flange 320 abuts the locking button 294 that protrudes beyond the opening 290. The flange 320 of the first air damper 200 can then push the locking button 294 away from the opening 290 and collapses the first stabilizer 280 when the third column 370 is fully nested within the first column 264. The air damper 400 may also have a recessed portion 422 on a perimeter surface 410 thereof.The recessed part 422 can receive the locking pin 430 (as shown in figure 17) which locks the first and third columns 218 to prevent relative axial movement between them.

[0075] Although the foregoing embodiments have been described with respect to one half of a folding ladder 210 (e.g., the first ladder part 250), the stabilizers 280, 282 of the second ladder part 254 are substantially similar to those of the first ladder part 250. For example, the second ladder part 254 may comprise a second stabilizer housing 440 having a pair of stabilizers 280, 282 extending beyond each of the first and second uprights of the second ladder part 254 in a direction substantially normal to the axis 220 of the plurality of columns 218 and folding into a hollow portion of the second stabilizer housing 440. The second stabilizer housing 440 may be close to the ground surface 272 when the first and second parts 250, 254 of the ladder form angles such as between approximately zero degrees and approximately 60 degrees (e.g., 0 degrees as illustrated in Figure 9A and 30 degrees as illustrated in Figure 9D), while the second stabilizer housing 440 is distal to the ground surface 72 when the first and second ladder parts 250, 254 form angles greater than 90 degrees (e.g., 180 degrees in Figures 9B and 9C). The stabilizers 280, 282 of the second ladder part 254 can collapse into the hollow part of the second stabilizer housing 440 when the plurality of columns 218 are nested one inside the other in a telescopic manner to collapse the ladder 210 into a collapsed position (e.g., as seen in Figures 9A and 9B), and wherein the stabilizers 280, 282 of the second ladder parts 210 can extend out of the second stabilizer housing 440 when the plurality of columns 218 are extended in a telescopic manner (e.g., as seen in Figures 9C and 9D).

[0076] During use, when the columns 218 of the first and second ladder parts 250, 254 are extended, the rim 320 moves away from the opening 290 of the first stabilizer housing 270 of the first ladder part 250 and the second stabilizer housing 440 of the second ladder part 254. The stabilizers 280, 282 of the first and second ladder parts 250, 254 extend out of the first and second stabilizer housings 270, 440 respectively, until the locking buttons protrude beyond the openings in line with the axis 220 of the columns 218. The first and second ladder parts 250, 254 can be locked in a desired angular position. The ladder 210 can be folded and the stabilizers 280, 282 can be collapsed during storage. To collapse the stabilizers 280, 282, the first and second ladder parts 250, 254 can first be unlocked from a desired angular position.The columns 218 of each of the first and second ladder parts 250, 254 can then be collapsed until a third column 370 is fully nested within the first column 264 and a fourth column 380 is fully nested within the second column 268. The flanges 320 of the air dampers 400 of the third and fourth columns 218 abut the opening 290 and the locking button 294 protrudes beyond it when the third and fourth columns 218 are fully nested within the first and second columns 218. The flange 320 pushes the locking button 294 inward into the hollow part of the respective stabilizer housing (e.g., the first and second stabilizer housings 270, 440) and thus collapses the stabilizers 280, 282 for storage.

[0077] Certain embodiments of the telescopic ladder 210 illustrated herein can improve safety by stabilizing the ladder 210 during use. For example, some embodiments of the telescopic ladder 210 with stabilizers 280, 282 extending from it ensure that the center of gravity of the ladder 210 always falls within the horizontal extension (e.g., the contact surface) of the ladder 210 during use, thereby minimizing or eliminating any moment that could tip the ladder 210 over during operation. In addition, the stabilizers 280, 282 can be collapsed during storage, thus facilitating the compact size of the ladder 210 when not in use. Furthermore, when the columns 218 of the ladder 210 are collapsed, the stabilizers 280, 282 collapse automatically, thus providing ease of use.

[0078] Therefore, some embodiments of the ladder are described. Although the present embodiments have been described in considerable detail with reference to certain described embodiments, the described embodiments are presented for illustrative purposes and not for limitation, and other embodiments are possible. A person skilled in the art will appreciate that various changes, adaptations, and modifications can be made without departing from the invention as defined in the appended claims.

Claims

1. A folding ladder (10), comprising: a first ladder part (14, 250); a second ladder part (16, 254) articulated to the first ladder part (14, 250), each of the first and second ladder parts (14, 16) comprising: a first upright (214); a second upright (216), the first and second uprights (214, 216) each having a plurality of columns (22) arranged along an axis of the plurality of columns (22); and a plurality of rungs (24) extending between the first upright (214) and the second upright (216), each rung (24) connected to a column of the first upright (214) and to a column of the second upright (216); a pair of hinge mechanisms articulatingly connecting the first part (14, 250) of the ladder to the second part (16, 254) of the ladder around a hinge axis (50), each hinge mechanism adapted to lock the first and second parts (14,16) of a ladder such that the first ladder part (14, 250) and the second ladder part (16, 254) form an angle with each other, each hinge mechanism comprising: a first hinge element (52) operatively connected to the first ladder part (14, 250); a second hinge element (54) operatively connected to the second ladder part (16, 254), the first and second hinge elements (52, 54) rotating relative to each other about the hinge axis (50); a shifting mechanism (70), comprising: a shifting pattern (72) defined by a plurality of grooves (74, 76, 78) peripherally positioned on the first hinge element (52), each groove corresponding to an angular position of the first ladder part (14, 250) with respect to the second ladder part (16, 254),and adjacent slots are separated by a defined distance along a perimeter of the first hinge element (52); and a selector pin (84) adapted to be displaced in the shift pattern (72) and received by a slot to lock the second ladder part (16, 254) in an angular position with respect to the first ladder part (14, 250); a locking plate (100) in the second hinge element (54), the locking plate (100) comprising a plurality of recesses (112, 114, 116) such that a center of the locking plate (100) coincides with the hinge axis (50), each recess separated from another recess by an angle corresponding to the angle between the first and second ladder parts (14, 16); and a locking pin (120) connected to the selector pin (84), the locking pin (120) adapted to be received by a recess in the locking plate (100),The locking pin (120) is configured to move in one direction along a locking pin axis, wherein the locking pin (120) moves into a recess in the locking plate (100) when the selector pin (84) moves into a slot in the shift pattern (72); the locking pin (120) moves away from a recess in the locking plate (100) when the selector pin (84) moves away from a slot in the shift pattern (72); and the locking pin (120) and the selector pin (84) are coupled such that the center axis of the locking pin (120) is located transversely at an angle to the axis of the selector pin (84).

2. The folding ladder (10) of claim 1, wherein the angle between the first and second ladder parts (14, 16) is between approximately 0 degrees and approximately 180 degrees.

3. The folding ladder (10) of claim 2, wherein the first and second parts (14,16) of ladder can be locked at angles of approximately 0 degrees, approximately 30 degrees and approximately 180 degrees.

4. The folding ladder (10) of claim 3, wherein the angle between a first recess (112) of the plurality of recesses (112, 114, 116) and a second recess (114) of the plurality of recesses (112, 114, 116) is approximately 30 degrees, and the angle between the first recess (112) and a third recess (116) of the plurality of recesses (112, 114, 116) is approximately 180 degrees.

5. The folding ladder (10) of claim 4, wherein the locking pin (120) is configured to be: fully received by a recess to lock the first ladder part (14, 250) and the second ladder part (16, 254) in an angular position; fully retracted from a recess to release the first and second parts (14,16) of a ladder in an angular position; and abut an edge of the second hinge element (54) when the first and second ladder parts (14, 16) are angled at any angle other than a plurality of predetermined angles.

6. The folding ladder (10) of any preceding claim, further comprising a selector collar (142) that slides with the first hinge element (52), the selector collar (142) engaging with the selector pin (84) and adapted to slide against the first hinge element (52) along a collar axis (144).

7. The folding ladder (10) of claim 6, wherein the selector collar (142) is adapted to rotate about the collar axis (144) to move the selector pin (84) along the groove defined on the first hinge element (52).

8. The folding ladder (10) of any preceding claim,further comprising one or more safety indicators, the safety indicators being adapted to provide a first indication when the first and second ladder parts (14, 16) are locked in an angular position and a second indication when the first and second ladder parts (14, 16) are unlocked.

9. The folding ladder (10) of any preceding claim, wherein each rung (24) comprises a flat upper surface and a second surface opposite the flat upper surface, wherein the first surface of the first and second ladder parts (14, 16) defines a flat support surface when the first and second ladder parts (14, 16) form an angle of approximately 180 degrees.

10. The folding ladder (10) of claim 9, wherein at least a portion of the first surface of the first and second parts (14,16) of the ladder forms an angle with respect to a horizontal plane.

11. The folding ladder (10) of any preceding claim, wherein the plurality of columns (22) are arranged in a nested arrangement for relative axial movement in a telescopic manner such that the ladder is extendable or foldable along the axis of the plurality of columns (22).

12. The folding ladder (10) of claim 11, wherein each rung (24) is connected to a column of the plurality of columns (22) by means of a connector unit (28), the connector unit (28) having a latch unit including a release button (246) sliding along a front surface of the rung (24) for selectively unlocking or locking relative axial movement between two adjacent columns (22) of the plurality of columns (22).the front surface of the step (24) being generally perpendicular to a plane normal to the axis of the plurality of columns (22) .,

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