Smart Ladder

Abstract

A ladder including sensors, controllers, and output signals for alerting a user of the ladder's operating status and assisting the user in safely operating the ladder.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 071,437, filed August 28, 2020, which is incorporated herein by reference.

[0002] The present invention relates to a ladder. Summary of the Invention

[0003] The ladder may incorporate a tilt sensor that determines whether the ladder is tilted within a desired angle range to minimize the ladder's slope or incline, allowing the ladder to generate a signal to the user. Lights may be included to make the ladder visible in dark areas (such as enclosed spaces) and to illuminate the surrounding area. Electrical outlets may be included on the ladder to power tools, lights, or other equipment. A tray may be provided for holding tools and hardware. The tray may include magnetic strips to hold items such as screws, nails, and screwdrivers. The sensor may detect when the user reaches the bottom rung of the ladder and cause the ladder to generate a signal to the user not to descend the ladder before reaching the bottom rung.

[0004] Additional features can be provided to facilitate access to OSHA-permitted confined spaces, particularly those accessed via manways. OSHA-permitted confined spaces have a permitting process used to ensure that it is safe to enter and work within the space. Some of the equipment needed in such spaces includes, but is not limited to, air sampling for up to four gases (oxygen, carbon monoxide, sulfur hexafluoride, and methane or low-explosive-level gases), temporary lighting, cameras, communication devices, power cables for tools used inside, and temporary ventilation ducts and hoses. These items block entrances to the space. In many cases, entrances are also exits. Blockages create congestion and increase the time required for normal entry and exit. In some cases, entrants can become tangled in the various hoses and cords in the manway, resulting in tripping and injury, and delays can be significant in emergencies such as fires, toxic gas releases, lightning strikes in the area, or other hazards. This ladder eliminates some of the clutter by incorporating and integrating the equipment into the ladder itself. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a front view of a ladder including many of the features described above (top tray omitted for clarity). [Figure 2] FIG. 2 is a left side view of the ladder of FIG. 1. [Figure 3] FIG. 2 is a right side view of the ladder of FIG. 1. [Figure 4] FIG. 2 is a plan view of the ladder of FIG. 1. [Figure 5] FIG. 2 is a side view of a tray that can be attached to the top of the ladder of FIG. 1. [Figure 6] FIG. 6 is a plan view of the tray of FIG. 5. [Figure 7] FIG. 2 is a side view of a light that can be connected to the power outlet of the ladder of FIG. 1. [Figure 8] FIG. 2 is a front view of a ladder including piezoelectric sensors that detect the position of a user's feet and hands in contact with the ladder as they ascend or descend the ladder. [Figure 9] 9 is a schematic exploded cross-sectional view taken along line 9-9 of FIG. 8. [Figure 10] 1 is a schematic diagram showing the recommended inclination angle of a ladder relative to a wall or other support. [Figure 11] FIG. 10 is a plan view of an alternative embodiment of a ladder. [Figure 12] FIG. 12 is a plan view of the ladder of FIG. 11 protruding from the manhole. [Figure 13] FIG. 12 is a side view of the ladder of FIG. 11 positioned for downward insertion into the enclosed space. [Figure 14] FIG. 12 is a side view of the ladder of FIG. 11 set for upward insertion into an enclosed space. [Figure 15] 12 is an outward-facing side view of the upright portion of the ladder of FIG. 11. FIG. [Figure 16] FIG. 12 is a side view of the ladder upright of FIG. 11 facing inward. [Figure 17] FIG. 17 is a front cross-sectional view of the ladder rung of FIG. 11 taken along line 17-17. [Figure 18] FIG. 18 is a cross-sectional view taken along line 18-18 of FIG. 17. [Figure 19] FIG. 19 is a cross-sectional view taken along line 19-19 of FIG. 17. [Figure 20] FIG. 12 is a schematic diagram showing the arms and hands of a user grasping a rung on the ladder of FIG. 11. [Figure 21] FIG. 12 is a plan view of the ladder rung of FIG. 11; [Figure 22] 22 is an exploded view taken along line 22-22 of FIG. 21, showing only the crossbar profile. [Figure 23] FIG. 1 is a schematic front view of a light pipe transmitting light rays from an LED light source. [Figure 23A] 12 is an exploded side view of the upright showing an alternative embodiment of the gas sampling mechanism on the ladder of FIG. 11. FIG. [Figure 24] FIG. 12 is a side view of a movable cargo tray that can be mounted on the ladder of FIG. 11. [Figure 25] FIG. 25 is an enlarged side view of the movable cargo tray of FIG. 24. [Figure 26] FIG. 26 is a plan view of the movable cargo tray of FIG. 25. [Figure 27] FIG. 15 is a schematic diagram showing components typically located inside the enclosed space of FIGS. 13 and 14 and components including an attendant box located outside the enclosed space. [Figure 28] FIG. 28 is a front view of the attendant box of FIG. 27. DETAILED DESCRIPTION OF THE INVENTION

[0006] 1-10 illustrate a ladder 10. Ladder 10 includes left and right uprights 12 and 14 (also called rails or side rails) and a plurality of horizontal rungs 16 extending between and connecting uprights 12, 14. Ladder 10 is preferably fabricated from a relatively lightweight, non-degrading, electrically insulating material such as fiberglass, although aluminum, steel, or other materials may be used in certain instances.

[0007] As best seen in FIG. 4 , each upright 12, 14 has a substantially “C”-shaped cross-sectional profile along its entire length, with first and second outwardly projecting legs 18, 20 connected by a connecting leg 21. The first leg 18 is thicker than the second leg 20. Each first leg 18 defines a longitudinal cavity 22 that extends substantially the entire length of the upright 12, 14. Within each longitudinal cavity 22 is housed an LED (light-emitting diode) light strip 24 that enhances the visibility of the ladder 10 (see also FIG. 2 ). The light strip 24 not only enhances the visibility of the ladder 10, but also provides ambient lighting. The open outer edge of the cavity 22 is closed with a lens 26, such as a polycarbonate strip, to protect the light strip 24 and diffuse the light emanating from the cavity 22.

[0008] The light strip 24 and all other electrical components (unless otherwise noted) may be battery operated. One or more batteries 146 (shown in FIG. 17) may be located within one or more of the horizontal rungs or within one (or both) of the uprights 12, 14. The batteries may be rechargeable, and the ladder 10 may include a battery charging station (not shown) that is automatically powered when an electrical cord is connected to the ladder 10, as described in more detail below. Additionally, some or all of these electrical components may be powered directly from an external power source, which may be direct current (DC) or alternating current (AC). The transition from battery operation to external power operation may be accomplished manually or automatically, as desired.

[0009] As shown in FIGS. 2 and 3 , each upright 12, 14 houses a load cell 28 to detect the weight on the ladder. These load cells 28 monitor the total load on the ladder 10, including the user and any gear the user is carrying (hoses, tools, equipment, supplies, etc.). The load is transmitted to a controller (not shown), preferably located on the ladder. The controller compares the load to specifications to ensure the maximum weight rating of the ladder 10 is not exceeded. If the weight detected by the load cell 28 exceeds the weight rating of the ladder 10, the controller can be programmed to generate an output signal to alert the user. The output signal may include an audible alarm attached to the ladder, a vibrator attached to the ladder that vibrates the ladder when activated, a light (such as the light strip 24) that can flash, change color, etc. The output signal may also include wireless transmission to a central station or an external receiver, such as a smartphone. It should also be noted that any of these alarm outputs may be used to alert the user to other conditions detected by the ladder 10, as will be discussed in more detail below.

[0010] The output signal can be customized to alert the user to specific safety concerns. For example, as described in more detail below, lights can flash at different intervals or change color to indicate specific alarms. A color, such as green, can be used to indicate that the user has reached the bottom rung of the ladder 10 and can safely descend to the ground. Another color, such as red, can be used to indicate an unsafe rest angle of the ladder 10 (too steep or too shallow) and therefore that the user should not climb the ladder 10 until it is repositioned to the correct angle α (see FIG. 10 ). Additionally or alternatively, different sounds or other outputs can be used to indicate different conditions. For example, a high-pitched sound can be used to indicate an unsafe angle, a pleasant musical tone can be used to indicate contact with the bottom rung, sounds of different pitches can be used to indicate different conditions, etc.

[0011] The load cells 28 also monitor the weight on each upright 12, 14 of the ladder 10. Again, this information is transmitted to the controller, which compares the weight on each upright 12, 14 and can activate an output to warn the user if one upright 12, 14 appears to be carrying a disproportionately large percentage of the total weight compared to the other. Ideally, weight should be evenly distributed on each upright 12, 14. If the load cells 28 detect an excessive discrepancy in weight distribution between the uprights 12, 14, this may indicate that the soil (or bedding) beneath one of the uprights 12, 14 is not sufficiently compacted and is likely to collapse. Upon receiving an output signal indicating an excessive load discrepancy, the user can step off the ladder 10, ensure both uprights 12, 14 are properly supported, and then re-enter the ladder.

[0012] At least one of the uprights 12, 14 defines an opening 30 in the connecting member 21 (see FIG. 3). The opening 30 is large enough to accommodate a person's finger for use as a handle for carrying the ladder 10. The location of the opening 30 is carefully selected to ensure that the ladder 10 is substantially balanced when lifted by a user at the opening 30. The dimensions of the opening 30 are such that a user can lift the ladder with a gloved hand.

[0013] The upper end of each upright 12, 14 defines a sloped surface or wedge 32 (see Figures 2, 3, and 10) which is cut at a 4:1 ratio (length four times its height) so that when the ladder 10 is erected at the correct safety angle α (note: at a 4:1 ratio, angle α is approximately 76 degrees) (see also Figure 10), the upper surface of each upright 12, 14 is substantially horizontal.

[0014] As previously mentioned, the angle α (see FIG. 10 ) between the ladder 10 and a horizontal support surface, such as a floor or ground, should be approximately 76 degrees, preferably between 70 and 82 degrees. The ladder 10 includes an inclination sensor 34, typically a low-frequency or DC-response accelerometer 34 (see FIG. 3 ), aligned with the ladder's linear axis to monitor the angle α of the ladder 10 relative to the horizontal when the ladder is in use and transmit that angle to the controller. If this angle is not within a desired range, the controller generates an output signal to alert the user. As previously mentioned, the output signal can be visual (a flashing light and / or a color change), audible (a buzzer or beep), and / or tactile (vibration), and these outputs can be continuous or varying frequencies to alert the user of various ladder conditions before climbing, during use, and before descending the ladder.

[0015] FIG. 8 is a front view of ladder 10 showing multiple contact sensors 36 positioned on rungs 16 (the bottom rung is labeled FIG. 16B). In this embodiment, as also shown in FIG. 9, each contact sensor 36 is a piece of piezoelectric film 38 attached to rung 16, 16B and covered by a protective cover 40. A piezoelectric sensor is a device that measures pressure changes by converting pressure changes into electrical changes using the piezoelectric effect. The contact sensor 36 on the bottom rung 16B (see FIG. 1) detects when the user reaches the bottom rung 16B. An optical transmitter and receiver 195 (see FIG. 16) positioned on uprights 12, 14 (or 102, 104) approximately one inch above the top surface of the bottom rung 16B can be used to detect when the user touches the bottom rung 16B. When the sensors 38 and / or 195 detect that the user has reached the bottom rung 16B, it is safe for the user to descend the ladder 10 to the ground. The contact sensor 36 or optical receiver 195 sends a signal to the controller 42, shown in FIG. 3, so that the controller 42 knows whether the user is on the bottom rung 16B. The controller generates an output signal to the user indicating whether the user is on the bottom rung 16B, so that the user knows when it is safe to descend the ladder. The output may be a short beep or other sound, a green light at the user's eye level indicating that the user is in contact with the bottom rung, a red light indicating that the user is not in contact with the bottom rung, or any other desired output signal. This signal, particularly if it is a sound, may be timed to be of relatively short duration so as not to annoy the user if the user intentionally stands on the bottom rung 16B for an extended period of time.

[0016] In this embodiment, the controller 42 is located in the same area as the tilt sensor. The battery, battery charger, and electronics for automatically switching from battery power to external power can also be located in this same area.

[0017] Additional contact sensors 36 located on some, but not all, of the other rungs 16 can be used as training aids to help the user learn how to safely use the ladder. When climbing the ladder, the user must maintain three points of contact on the ladder (two hands and one foot, or two feet and two hands). The contact sensors 36 send signals to the controller, allowing the controller to constantly monitor the presence of three points of contact by the user. The controller can also record and transmit the three-point contact data along with time / date data, which can be displayed graphically on an output device (near or far from the ladder) to show the user's progress during training exercises and regular use and how well the three-point contact goal is achieved when ascending or descending the ladder. The controller 42 can activate one or more output signals to alert the user as to whether or not they have three points of contact with the ladder. The signal should be of short duration so as not to annoy the user if he or she is intentionally standing on the ladder rung and using both hands to perform some action other than climbing up or down the ladder.

[0018] Returning to FIG. 4 , one of the two uprights 12, 14 (the right upright 14 in this embodiment) houses an electrical extension cord 44 that extends lengthwise along the ladder 10. A male power cord plug receptacle 46 (see FIG. 3 ) is located at the bottom of the upright 14, and a female power cord plug GFCI receptacle 48 is located at the top of the upright 14. (Alternatively, the power cord may be reversed to allow power input at the bottom and output at the top, or additional power cords may be provided within the ladder to allow output at other desired locations.) The extension cord 44 can be plugged into an external power source via the male plug 46. Any electrical accessories, such as power tools, lights, and battery chargers, can be plugged into the female plug 48. As previously mentioned, once the extension cord 44 is plugged into AC power, electrical / electronic devices on the ladder 10 can switch from battery power to AC power. This switch can be performed manually or automatically.

[0019] A telescoping mast 50 (see FIGS. 2, 4, and 10) is housed at the top of the upright opposite the one housing the extension cord 44 (in this case, the left upright 12). The mast 50 is shown in phantom in the stowed position in FIG. 2 and in phantom in the extended position in FIG. 10. A user can slide the mast 50 above the top of the ladder 10 to use it as a handle / support for stability when, for example, climbing onto a roof or platform above the end of the ladder 10. The mast 50 can be locked in the extended position by any of a number of means. For example, the mast 50 can be simply twisted along its longitudinal axis until it locks against the sliding mechanism of the mast 50.

[0020] 5 and 6, a tray 52 can be mounted on the ladder 10, resting on the wedges 32. The tray 52 can be secured by any known means, including bolts, clamps, magnets, or industrial-strength hook-and-loop fasteners (not shown). The tray 52 defines a plurality of through-holes 54, 56 for receiving tools (not shown), such as screwdrivers and wrenches. The tray surface is divided by easily removable walls 58 that can be lifted from between wall guides 60. A magnetic strip 62 provides an additional location for temporarily holding tools, such as screwdrivers. A plurality of hooks 64 below the tray 52 can be used to hold hanging items, such as paint cans.

[0021] FIG. 7 shows a commercially available plug-in saber light fixture 66. This saber light 66 features a bright LED portion 68, and a rubberized handle 70 provides a non-slip grip at the gripping end, including a male plug 72 that plugs into the female electrical plug 48 (see FIG. 3) to charge an onboard battery or illuminate the surrounding environment while connected to the ladder's electrical outlet. This is just one example of a tool that may be plugged into the ladder's electrical outlet. Any other corded or cordless tool can be connected to the ladder 10 to utilize this mechanism.

[0022] When a sensor on the ladder 10, such as an accelerometer 34 (see FIG. 3), detects that the ladder is moving, the controller illuminates a light strip 44 on the ladder 10. This is a safety feature to illuminate the area through which the ladder 10 is being moved and to illuminate the ladder 10 itself, making it more visible to personnel around the area through which the ladder 10 is being moved. In a preferred embodiment, the ladder 10 is sealed to make it fully waterproof against "spray-downs" and "wash-downs."

[0023] It should be noted that unless otherwise stated, all features disclosed with respect to this embodiment of ladder 10 also apply or may apply to alternative embodiments described later in this specification.

[0024] Figures 11 through 29 illustrate an alternative smart ladder 100. Referring to Figures 11 through 13, the ladder 100 includes left and right uprights 102, 104 and a plurality of rungs 106 extending between and connected to the uprights 102, 104. The frames of the uprights 102, 104 are preferably mirror images of each other, even though the items contained within the frames are likely to be substantially different from one another, as will be described in more detail below.

[0025] Referring to FIG. 11, to establish common terminology, the front or entry side of the ladder is designated "F," the back side of the ladder is designated "R," the outward-facing side of each upright 102, 104 is designated "OF," and the inward-facing side of each upright 102, 104 is designated "IF." As will become clear, this ladder 100 is designed for front-side use only and is particularly useful for accessing confined spaces requiring OSHA approval, such as confined space 108 of FIG. 13 (showing ladder 100 used to access confined space 108 below via manhole 110) or confined space 112 of FIG. 14 (showing ladder 100 used to access confined space 112 above via manhole 114).

[0026] FIG. 12 is a plan view of the mechanism shown in FIG. 13, in which the ladder 100 is used to access a confined space 108 below through a circular opening in a manhole 110. This ladder 100 differs from the first embodiment 10 in several respects. First, the uprights 102, 104 are angled toward each other, diverging in front and narrowing in rear. (The angle β between an imaginary line 116 extending parallel to the rung 106 and an imaginary line 118 extending from the leading edge to the trailing edge of each upright 102, 104 is less than 90 degrees.) This allows the user maximum access to the ladder at the front, keeping them as close as possible to the supporting wall of the manhole opening 110. This angled configuration creates a more open opening at the front "F" of the ladder 100 than at the rear "R." This allows the user to easily place their foot on the rung 16 from the front "F." This also guides the user's feet into good alignment with the rungs 106 before the user ascends or descends the ladder 100. The tilt creates more space for the user to maneuver through the manway 110 than is possible with a standard ladder, allowing the user's torso to fit closer to the supporting wall and more snugly against the ladder 100. This helps the user maneuver around the manway 110 or other obstacles that limit the space around the ladder 100.

[0027] The second difference is that rung 106 does not extend through the center of uprights 102, 104, but is offset rearward relative to uprights 102, 104. That is, rung 106 is closer to the non-entry or rear "R" side of ladder 100 than to the entry or front side of ladder 100. By offsetting rung 106, a user can be closer to the longitudinal center of ladder 100, thereby increasing the clearance between the user and a manway or other obstacle, allowing the user to pass through more easily and quickly. Rapid escape from confined spaces is important in the presence of situations such as lightning or a nearby hazardous vapor release, and the tilt and offset features of ladder 100 help personnel quickly and easily escape from confined areas or other work areas.

[0028] FIG. 11 shows the profiles of the uprights 102, 104 in bold. Looking at the left upright 102 (the right upright 104 has a profile that is a mirror image of the left upright 102), the profile defines a first cavity 120, a second cavity 122, and a third cavity 124. The profile cavities 120, 122, 124 extend the length of each upright, thus forming channels along the length of the uprights 102, 104. The first and second cavities 120, 122 are inwardly open. The third cavity 124 is outwardly open. The first cavity 120 can be used to house, support, and guide a bearing set 126 for a movable cargo tray 128, shown in FIGS. 24-26. A curved lip 130 at the front of the first cavity 120 partially closes the first cavity 120 and can be used as a handle for lifting the ladder 100, even when wearing gloves. This same curved lip 130 (see also FIG. 20) can be used as a fastener for the forearm 112 to provide a fifth contact point on the ladder, as will be described in more detail below. This is an inward-facing "IF" cavity 120; that is, it opens to the interior surface of the ladder 100.

[0029] The second cavity 122 can be used to house electrical wiring and / or compressed or sampled air conduits for gas monitors, as needed and as will be described in more detail below. This is also an inward-facing "IF" cavity; that is, it opens to the inside of the ladder 100. This cavity 122 is closed with a barrier strip 132 that extends the length of the cavity 122. The cavity 122 can be potted to completely surround and seal the cavity 122 to create a watertight cavity 122.

[0030] The third cavity 124 is an outward-facing "OF" cavity and is used to house an LED light strip 134 mounted on a circuit board 136 controlled by a controller, as described below. This third cavity 124 is closed with a barrier strip 138 that extends along the length of the cavity 124 and is coated with silicone to completely surround and seal the cavity 124 to ensure a watertight cavity 124. The barrier strip 138 and coating material are translucent, allowing light from the LED strip 134 to provide ambient illumination. These LED lights 134 can be selectively activated by the controller, as described below, with respect to color, on / off frequency, and intensity, to function as a signal or alarm for personnel within the confined space 108 or on the ladder 100. It should be noted that the barrier strip 138 is recessed from the outer surface OF of the profile to protect the barrier strip 138 from damage or scratches.

[0031] Finally, the profile of the upright 102 terminates in a fourth inwardly facing opening 140 and an inwardly curved lip 142. The lip 142 can be used as a handle for lifting the ladder 100, even when wearing gloves.

[0032] 17-22, each rung 106 extends the distance between the uprights 102, 104 and is preferably secured to the uprights 102, 104 by a rivet 144 (see FIG. 15). FIG. 18 is a cross-sectional view of a rung 106 taken along line 18-18 in FIG. 17. (While FIG. 17 is a front cross-sectional view of FIG. 16, it will be understood that FIG. 18 is a view through the entire rung, not just the portion of the rung shown in FIG. 17.) As shown in FIGS. 17 and 18, one or more batteries 146 can be housed within the rung 106. These batteries 146 are preferably rechargeable batteries that are automatically recharged when the ladder 100 is connected to an external power source. The rung 106 defines a downwardly and rearwardly open longitudinal cavity 148 that extends the entire length of the rung 106 and houses an LED strip 150 that illuminates the area below and behind the rung 106. Like the similar cavity in ladder 100, this cavity 148 is closed with a barrier strip 152, in this case a translucent strip 152, to seal LED strip 150 from the environment. This cavity 148 can be coated with a translucent material to make the cavity 148 waterproof.

[0033] FIG. 19 is a cross-sectional view of rung 106 taken along line 19-19 in FIG. 17. (Like FIG. 18, this is a view through rung 106, not just the portion of the rung shown in FIG. 17.) FIGS. 17 and 19 show that rung 106 defines at least one aperture 154 that allows light to shine forward from rung 106, out the end of a light pipe 156, toward a person climbing the ladder. A light pipe is an optical component typically used to increase the uniformity of a light source or to guide light. In this example (see FIG. 23), light pipe 156 receives light from an LED light source 158 located on one of uprights 102, 104 and guides it into the forward-facing aperture 154 in rung 106. The LED light source 158 is mounted on a circuit board controlled by a controller, described below, and can be used to notify or warn a user on ladder 100. The opening 154 in the rung 106 is positioned at eye level with the user when standing on the ground or on a ladder rung so that the user can easily see the signal 160 (see FIG. 23) when ascending or descending the ladder 100.

[0034] 18-22, the rung 106 has a nose 162 at its trailing edge and a tail 164 at its leading edge. Extending between the nose 162 and tail 164 is an arcuate upper surface defining a plurality of ribs 166 for improving the grip of the foot or hand on the rung 106. The tail 164 defines a first shallow concave surface 168, which functions as a thumb contact area. The nose 162 defines a second deep concave surface 170 opposite the first shallow contact surface 168. A user grasps the rung 106 by placing their thumb 306 in the first shallow concave surface 168 of the tail 164 (see FIG. 20). The remainder of the user's hand overlaps the ribs 166 on the upper surface, with the fingers 308 nested within the second concave surface 170 of the nose 162. The user's palms rest on the grip-enhancing ribs 166. This provides a natural grip on the rung 106 during ascent and descent, especially when passing over manways or around other obstacles.

[0035] A user should have three points of contact for best support when ascending or descending. This type of use requires practice and training. When ascending or descending prior art ladders, a user's arms bend at the elbows and wrists. With conventional rungs or flat rungs, if a user slips and loses foot contact, resulting in contact with only one or both hands with both wrists and elbows bent, injury is possible if the user's grip prevents the fall. In the configuration described in this embodiment of ladder 100, the user's grip keeps the wrists aligned with the forearms 172 (see FIG. 20), resulting in less stress on the wrists if foot contact is lost.

[0036] To ascend or descend a prior art ladder using two legs and two hands, at least one of the four contact points must move. To maintain movement, each hand and foot must move in a highly coordinated manner that is difficult for most users to master. The present invention allows the operator to create a temporary fifth contact point 174 (see FIG. 20) to significantly improve ladder safety by preventing injury and falls.

[0037] The design of rung 106 encourages the user to align their wrist and forearm 172 and contact the rounded lip 130 of the entry side "F" of ladder 100 at point 174. This provides a means for the user to create five points of contact with the ladder as follows: grasp rung 106 and press forearm 172 into the rounded inner front edge 130 of upright 102 at contact point 174 while pushing out with the opposite foot. This establishes three points of contact with one foot, one hand, and one forearm pressed into the rounded edge 174 of ladder 100, while the other foot and other hand are free to move, providing the user with good support while adding mobility.

[0038] 15 shows the "OF" side of the uprights 102 facing outward. The rivets 144 securing the LED light strips 134 and rungs 106 are shown. Also shown are electrical outlets 176 on the top and bottom of the uprights 102. These outlets 176 may be used to power electrical devices, including electrical extension cords, if desired. The outlets 176 may be powered by a battery internal to the ladder 100 and / or by an external power source, as described with respect to the first embodiment. A handle 178 on the top of the ladder 100 is used to lift the ladder 100 and place it in place.

[0039] 16 shows the inward-facing "IF" side of upright 102. This upright contains several accessories, many of which may be present on both uprights 102, 104, and are described below. Many of these accessories communicate with receivers outside the enclosed space, as will be described later. The accessories include:

[0040] RFID Reader 180: The ladder is used in several spaces simultaneously, including many entrances. The same entrant may enter and exit a space multiple times during a work period. If the work space is an OSHA-permitted confined space, such as space 108 in FIG. 13, an attendant located outside the confined space 108 must record the entrant, the entrant's name, the time they entered the confined space, the time they left the confined space, and the time spent in the area. The attendant may also be tasked with double-checking that the entrant has the necessary ID and all necessary credentials to enter such a confined space 108. This can be a tedious and time-consuming process. In this embodiment, each entrant is issued a unique radio frequency identification (RFID) card containing most of this information prior to entry. Upon entering or exiting the space, the entrant scans the RFID card with RFID reader 180 to record their status. A remote device connected to ladder 100 (such as printer 280 in FIG. 28) records and prints the entrant's name, entry and exit, if necessary, and the time and date of entry and exit. One RFID reader 180 on one upright 102 is used to enter the space, and a second RFID reader 180 located on the opposite upright 104 is used to exit the space, thereby automating and speeding up the recording of personnel entering and exiting the confined space.

[0041] Man Down Plug 182: An attendant or entrant can pull the plug 182 from the upright 102 to indicate the presence of a man down, which signals the controller to activate alarms both inside and outside the confined space to initiate a response by emergency responders.

[0042] Four Gas Monitors 184: Four gas monitors 184 are incorporated into the ladder 100 to eliminate the need for a sample hose to be routed through the manway 110. In fact, the sample hose often becomes pinched at the point where personnel or equipment pass through the manway 110 while entering or exiting the space 108, during which time the atmosphere within the controlled space cannot be monitored. This gas monitor 184 eliminates the problem of pinched sample hoses by monitoring the gases in situ and eliminating the sample hose.

[0043] FIG. 23A illustrates an alternative embodiment of an arrangement for monitoring the atmosphere with a four-gas monitor 184. In this arrangement, a manifold 186 extends the length of the upright 102, and a number of three-way valves 188 are sequentially opened by a controller while remaining closed to sample the atmosphere around the ladder 100 at multiple elevations along its height. The four-gas monitor 184 may be positioned at any convenient location on the ladder 100 in fluid communication with the manifold 186, and thus with the three-way valves 188. In a preferred embodiment, the four-gas monitor 184 is easily accessible and removable for removal for calibration. Readings from the four-gas monitor 184 are transmitted to a controller, which can generate alarm outputs both inside and outside the confined space to prompt evacuation of the confined space if an unsafe condition is detected by the monitor 184.

[0044] Speaker / Vibrator 190: Referring again to Figure 16, one or more speakers / microphones 190 are included for audio communication between people inside and outside the enclosed space 108. Additionally, a vibrator (also 190) can be used to alert an intruder if the contact sensor 36 described with respect to the first embodiment and present in this embodiment detects contact between the ladder 100 and an intruder.

[0045] Cameras 192: Video cameras 192 allow attendants and others to visually communicate with entrants to ensure their safety, needs, and progress. In a preferred embodiment, the video cameras 192 are capable of recording in IR (infrared) frequencies, allowing events and personnel to be recorded even at night or when visibility within the enclosed space 108 is extremely poor due to smoke, for example. In this example, at least some of the LED lights 134 are capable of emitting light in IR frequencies. These cameras 192 may be wide-angle cameras that capture a large portion of the workspace area.

[0046] Plug receiver 194: The plug receiver 194 mounted near the top of the ladder 100 is designed to fit a custom-shaped plug for powering the ladder 100 and charging the battery 146. (Another plug receiver 194 may be provided near the bottom of the ladder, if desired.)

[0047] Circuit Board 196: A custom circuit board 196 with a gasket cover 198 is used to communicate with various components including: A computer to control and manage monitoring and reporting for various sensors, transducers, LEDs, battery charging, RFID, and remote data input / output devices. Video input / output for processing and transmitting video data from camera 192 outside space 108. A DC response accelerometer to measure the tilt angle α, which is used by the computer to alert the user via a speaker, vibrator, and / or flashing light that the ladder 100 is not at the correct tilt angle. LED lights to provide ambient lighting and illumination for the location directly below the bottom rung, with the LEDs facing inward where a person's feet would be before climbing the ladder 100 and where the feet would first contact the floor or other surface when descending the ladder. A Bluetooth or other wireless link to provide a communications link between the ladder 100 and another device, such as a laptop computer or other communications device.

[0048] overview: 27 is a schematic diagram showing components located within the enclosed space indicated by dashed line 200 and also showing components, including attendant boxes, located outside the enclosed space indicated by dashed line 202. Some components not located within dashed lines 200, 202 may be located either inside or outside the enclosed space.

[0049] As shown in FIGS. 13 and 14 , the ladder 100 is often placed within a confined space 108. As described with respect to FIG. 16 , there is a connector 194 on the ladder for connecting external power to the ladder 100. FIG. 27 shows that the connector 194 on the ladder is a special connector with a keyway 204 that receives power by connecting to a plug 210 having a mating key 208 that connects to the keyway 204 of the connector 194. This typically powers the ladder with 24 VDC power. A cord 44 inside the ladder described with respect to the first embodiment then powers accessories such as LED lights, a battery charger, a gas monitor, a camera, an inclinometer, a circuit board, a computer, a Bluetooth link, RFID, a load cell, and a speaker. These accessories can either connect internally to the cord 44 or can be plugged into the ladder's outlet 176 that is connected to the cord 44. The plug 210 may be connected to the inside or outside of the enclosed space 108 depending on the arrangement of the ladder 100 .

[0050] Outside the confined space, as indicated by dashed line 202, are a 100-240 VAC power supply 216, a regulated 24 VDC universal power supply 218, and an attendant box 220. The attendant box 220 may be implemented, for example, as a personal computer, a tablet, a virtual touchpad device, or a traditional control panel. The attendant box 220 includes an antenna 222 for Bluetooth communications and may include a cable or other connector 224 for remote wired communications. These Bluetooth and wired communications may be with the ladder 100 within the confined space or with devices outside the confined space. It is also anticipated that the attendant box 220 will include some hardware, such as an emergency button, that can be pressed if necessary without scrolling through menu screens.

[0051] Companion Box: FIG. 28 shows an example of an attendant box 220 that includes:

[0052] Entrant Alert Button 226: Pressing this button provides one or more signals to the entrant indicating an urgent need to communicate with the entrant, for example, to direct the entrant to a manway for verbal instructions.

[0053] Exit Immediately button 228: Pressing this button will cause an alarm to sound within the confined space, such as by lighting a red LED on the ladder 100, sounding a speaker or buzzer, or playing the message "Exit Immediately."

[0054] Sick Person Button 230: Pressing this button alerts emergency personnel that there is a sick person in the enclosed space.

[0055] Emergency loudspeaker button 232: Pressing this button activates loudspeaker 234.

[0056] Time Clock 236: Shows local time

[0057] No Entry Light 237: Red light, leave immediately

[0058] Allowance Valid Time Remaining Clock 238: Displays a countdown timer indicating the time remaining that the closed entry permit is valid.

[0059] Entry OK Light 239: Green light indicates the enclosed space is ready to enter

[0060] Attendant-indicating camera 240: This camera is aimed at the attendant and transmits video to another location to confirm the attendant's presence.

[0061] 4 Gas Monitor Lights: High level alarm light 242: Red. Start leaving immediately. No Flow Light 244: Yellow 4 Gas Monitor Air Pump is not detecting flow. Activates beep sound Atmosphere Light OK246: Green 4 Gas Level Monitor Display 248: Shows the values ​​of all monitored gases Number of Entrants 250: Displays the total number of people in the enclosed space Entrant Data Display and Video Monitor 252: Shows the names of entrants and the time each entrant spent in the enclosed space. NOTE: This monitor can be switched to a video monitor showing a video image from a camera 192 on the ladder 100.

[0062] Sensor warning lights include: Internal noise level 254 Internal dust level 256 Internal stress level 258 AC power disconnect 260 Ladder Line Power Supply 262: Green Ladder Battery 264: Yellow Ladder Battery Power Low 266: Red

[0063] The digital display includes: internal temperature 268 Internal humidity 270 Internal Thermal Stress 272 External temperature 274 external humidity 276 External Thermal Stress 278

[0064] Other external connections include: Connecting to a printer 280 Connecting to a microphone 282 Connecting to headphones 284 Connecting to an Antenna 286 Connection for data cable 288 Connection 290 for 24V DC input

[0065] All data transmitted to and from the controller can be sent to the attendant box 220 via antenna 286. The attendant box 220 also contains a transmitter that allows the attendant box 220 to send data or commands to the controller mounted on the ladder. For example, if the leave now button 228 is pressed, the attendant box 220 generates a signal that is sent to the controller, generating a signal from the ladder informing people in the confined space that they must leave immediately.

[0066] FIGS. 24-26 show a movable cargo tray 128 that can be mounted on the ladder 100 to lift and lower cargo without requiring a person on the ladder 100. The tray 128 rests on bearings 126 that run along the cavities 120 in the left and right uprights 102, 104 as shown in FIG. 11. As shown there, there are a pair of upper and lower bearings 126 on each side of the tray 128, with one pair of upper and lower bearings 126 received in each upright 102, 104. As best seen in FIG. 25, the tray 128 is connected to the left and right bearings 126 by left and right rods 292 with intermediate tie screws 294. The intermediate tie screws 294 can be adjusted to ensure that the tray 128 is substantially horizontal regardless of the rest angle α (see FIG. 10) of the ladder 100.

[0067] As shown in FIG. 26 , the tray 128 includes a cam lock 296 designed to lock the tray 128 against the wall of the cavity 120 and prevent it from moving along the cavity 120. The cam lock 296 presses against the wall 298 in the area shown in FIG. 11 . Of course, other braking / locking mechanisms may be used instead of or in addition to the cam lock 296. The tray 128 also includes anchor points 300 so that a rope 302 or pole can be secured to the tray 128 from an elevated position above the tray 128 to raise or lower it. The tray 128 may have raised sides 304 to prevent items on the tray 128 from falling.

[0068] It will be apparent to those skilled in the art that changes may be made to the above-described embodiments without departing from the scope of the invention as claimed.

Claims

1. left and right uprights interconnected by a plurality of rungs, including a bottom rung; a bottom rung sensor that detects when a user is standing on the bottom rung of the ladder; a plurality of contact sensors provided on the plurality of crossbars; a controller mounted on the ladder and in communication with the bottom rung sensor and the plurality of contact sensors; Equipped with the controller activates an output signal mounted on the ladder indicating whether a user is on the bottom rung; The controller determines whether the user has three points of contact with the plurality of contact sensors based on inputs received from the plurality of sensors.

2. 2. The ladder of claim 1, wherein the lower rung sensor comprises an optical receiver mounted on one of the uprights and a transmitter mounted on the other of the uprights, the optical receiver and transmitter being mounted a short distance above the lowest rung.

3. A ladder as described in claim 1, wherein the controller generates an output signal on the ladder informing the user whether or not the user has three-point contact with the contact sensor.

4. 2. The ladder of claim 1, further comprising outwardly facing elongated grooves in the left and right uprights and an outwardly lit light strip extending along and sealed within the outwardly facing grooves, the outwardly lit light strip being in communication with the controller.

5. 2. The ladder of claim 1, wherein the left and right uprights are angled so that they diverge from one another at the front and narrow from one another at the rear.

6. 6. A ladder according to claim 5, wherein said rungs are offset towards the rear of said left and right uprights.

7. 2. The ladder of claim 1, wherein the left and right uprights define an elongate direction and define a plurality of grooves extending in the elongate direction, at least one of the grooves being coated to accommodate wiring and seal the wiring from water damage, and the controller is mounted on the ladder in communication with the wiring.

8. 8. The ladder of claim 7, further comprising an on-board battery mounted on said ladder in communication with said wiring.

9. 9. The ladder of claim 8, wherein the on-board battery is mounted within a hollow interior defined by one of the rungs.

10. 10. The ladder of claim 9, further comprising an RFID reader attached to one end of the ladder for detecting a user's movement onto the ladder.

11. 9. The ladder of claim 8, wherein the ladder includes a telescoping mast.

12. 9. The ladder of claim 8, wherein the ladder includes a gas monitor in communication with the wiring.

13. 9. The ladder of claim 8, wherein the ladder includes a Bluetooth link and a camera in communication with the wiring.

14. 9. The ladder of claim 8, wherein the ladder includes a movable cargo tray that moves up and down along at least one of the elongated channels.

15. 9. The ladder of claim 8, wherein the ladder includes a speaker and a microphone in communication with the wiring.

16. 9. The ladder of claim 8, wherein the ladder includes a vibrator in communication with the wiring.

17. 9. The ladder of claim 8, wherein the ladder includes a camera in communication with the wiring.

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