WO2016196433A1

WO2016196433A1 - Self-propelled robotic swimming pool cleaner with extendible arms for climbing out of a swimming pool

Info

Publication number: WO2016196433A1
Application number: PCT/US2016/034960
Authority: WO
Inventors: William Londono; Ethan Hanan; Aleksandr Klebanov; Anthony MELETTA
Original assignee: Aqua Products, Inc.
Priority date: 2015-05-29
Filing date: 2016-05-31
Publication date: 2016-12-08
Also published as: US20180155945A1

Abstract

A self-propelled robotic pool cleaner for cleaning a swimming pool having a bottom surface, and a vertical sidewall terminating at a deck. The cleaner includes an interior chamber with a water pump and a filter. Water beneath the cleaner is drawn through an inlet and flows into the interior chamber, and filtered water is discharged through an outlet. Rotationally-mounted supports support and guide the cleaner along a pool surface. An electric motor mounted in the interior chamber is configured to move the cleaner on the pool surface. An arm assembly includes a first arm member having a distal end which is selectively extendible beyond a front end of the housing. A support member projecting from the distal end is configured to extend over and directly contact the deck to support the cleaner while the pool cleaner advances up the vertical sidewall of the pool.

Description

SELF- PROPELLED ROBOTIC SWIMMING POOL CLEANER WITH EXTENDIBLE ARMS FOR CLIMBING OUT OF A SWIMMING POOL

CROSS REFERENCE TO RELATED APPLICATIONS

[001 ] This patent application claims the benefit of U.S. Provisional Application number 62/168,069, filed May 29, 2015, the content of which is incorporated by reference herein in its entirety.

Field of Invention

[002] This invention relates to self-propelled robotic pool cleaners, and more specifically, to a self-extracting robotic pool cleaner and a method for automatically climbing out of a swimming pool.

Background of Invention

[003] Self-propelled robotic pool cleaners include one or more drive motors to move or otherwise propel the cleaner over a surface of a pool being cleaned. Electric power to the cleaner is provided by an external power supply via a power cable, which is typically fabricated from two wire conductors having sufficient length to enable the cleaner to move over the bottom and side surfaces of the pool. The power supply provides electrical power to drive one or more electric motors that propel the cleaner over the pool surfaces. For example, the one or more motors can rotate the wheels, roller brushes, and/or tracks via a gear/belt drive assembly. Alternatively, a pump motor having one or more propellers can be used to discharge a pressurized stream of filtered water in the form of a water jet that also propels the cleaner in a direction opposite the water jet. The incoming power from the power cable can also be directed to an on-board controller that includes a microcontroller, logic circuity and/or programs to control the movement of the cleaner. The movement of the cleaner can be random, but is preferably in accordance with a predetermined cleaning pattern.

[004] The robotic pool cleaner includes one or more inlets formed at the bottom of the cleaner housing through which water and debris are drawn into the housing interior for filtering. The filtered water is then discharged from the cleaner back into the pool. [005] Once the pool has been cleaned, the cleaner is typically removed manually from the swimming pool by lifting the cleaner out and placing it on a pool deck or a cart brought near the edge of the pool. The power cable is often pulled or otherwise "reeled in" by a user from the edge of the pool until the cleaner can be grasped by hand and manually lifted out of the pool.

[006] Pool cleaners are generally configured to be essentially neutrally buoyant when submerged in the water. However, once the cleaner is adjacent the sidewall of the pool and being lifted out, the cleaner becomes heavier and more difficult to extract due to the weight of the cleaner itself plus any pool water that does not quickly drain from its interior chamber. As some individuals find that manually removing the pool cleaner from the pool can be time consuming and physically demanding, it would be advantageous to provide a robotic pool cleaner that can automatically climb up a vertical sidewall and self-extract itself out of the swimming pool.

Summary of Invention

[007] The disadvantages heretofore associated with the prior art are overcome by the present invention of a method of extracting a self-propelled robotic pool cleaner from a swimming pool, the robotic pool cleaner configured to ascend a generally vertical sidewall of the swimming pool, the cleaner comprising a housing including a front end and an upper portion disposed over a lower portion to define an interior chamber, the lower portion including a water inlet and the housing having a water discharge port for discharging filtered water, rotationally-mounted supports for supporting and guiding the cleaner on a pool surface, a filter assembly for filtering water drawn through the water inlet, and an electric motor mounted in the interior chamber and configured to move the cleaner on the pool surface, the method comprising the steps of: advancing the cleaner to ascend the sidewall of the pool and generating a first signal when a portion of the front end of the cleaner is in proximity of the waterline on the sidewall of the pool; extending a first arm assembly a predetermined distance from the front end of the housing in response to the first signal; and providing a support member from the first arm assembly to a position above the deck, the support member being configured to support the cleaner directly from a deck surface of the pool.

[008] In one aspect, extending the first arm assembly comprises extending a distal end of said first arm assembly beyond the waterline of the pool. In another aspect, the method further comprises: positioning the support member over the deck surface; and retracting the first arm assembly while maintaining the support member at its position over the deck surface to thereby provide support for the cleaner along the sidewall. In another aspect, extending the first arm assembly further comprises extending the first arm assembly laterally outward from a side portion of the cleaner prior to extending the first arm assembly beyond the front end of the housing.

[009] In one aspect, providing a support member comprises positioning a second arm member from the first arm assembly in a direction towards the sidewall of the pool. In yet another aspect, positioning the second arm member comprises the steps of moving the second arm member relative to the first arm assembly in the direction of the advancing cleaner; and rotating the second arm member from the first arm assembly over the deck surface about the pool. In still another aspect, the method further comprises retracting the first arm assembly in a rearward direction; and maintaining the second arm member over the deck surface.

[0010] In another aspect the method further comprises rotating one or more of the rotatably-mounted supports to ascend the sidewall of the pool; maintaining, by the second arm member, a downwardly directed force on the deck surface until the cleaner is extracted from the pool; and retracting the first arm assembly and second arm member once the cleaner is extracted from the pool. In still another aspect, the method comprises the step of moving the cleaner to a predetermined location outside of the pool.

[0011 ] In one aspect, the method further comprises performing a pool cleaning operation on a bottom surface of the swimming pool prior to the step of causing the cleaner to ascend a sidewall of the pool.

[0012] In another embodiment, a robotic pool cleaner for cleaning a swimming pool having a bottom surface, a sidewall having a lower portion adjoining at the bottom surface of the pool and an upper portion terminating at a deck extending generally horizontally about the pool is provided. The cleaner comprises a housing including an upper portion disposed over a lower portion to define an interior chamber, the lower portion including a water inlet, and a water discharge port in the housing for discharging filtered water; rotationally-mounted supports for supporting and guiding the cleaner on the pool surface; a filter assembly for filtering water drawn through the water inlet; an electric motor mounted in the interior chamber and configured to move the cleaner on a pool surface; and an arm assembly including an extendible and retractable first arm assembly having a distal end which is selectively extendible from the housing a predetermined distance beyond a front portion of the housing and configured to support the cleaner directly from the deck while the pool cleaner is positioned on the sidewall of the swimming pool.

[0013] In one aspect, the housing has a longitudinal axis that is substantially normal to the front portion, and the extendible arm assembly is configured for movement normal to the longitudinal axis. In another aspect, the housing has a longitudinal axis extending substantially normal through the front portion, and the extendible arm assembly moves in a direction of the longitudinal axis.

[0014] In yet another aspect, the first arm assembly comprises an elongated rail configured for movement with respect to the housing; and a first electric drive motor that controls the movement of the elongated rail. In still another aspect, the elongated rail includes a first plurality of teeth arranged along a length of the rail, the elongated rail having its longitudinal axis parallel to the longitudinal axis of the cleaner, and the first electric drive motor including a drive gear that rotatably interfaces with the first plurality of rail teeth to move the elongated rail in the direction of the longitudinal axis.

[0015] In one aspect, the pool cleaner further comprises a side plate mounted on a side of the housing, the side plate including an elongated channel configured to receive the extendible arm assembly; and the first electric drive motor is configured to move the first arm assembly laterally with respect to the elongated channel. In another aspect, the pool cleaner further comprises a second arm member that is attached to and configured to move along the first arm assembly. In still another aspect, the second arm member is rotatably attached to a second electric drive motor which is movably mounted on the elongated rail. In yet another aspect, the second arm member rotates approximately ninety degrees with respect to the first arm assembly. In one aspect, the second arm member pivots approximately ninety degrees with respect to the first arm assembly upon contacting a projecting stop on the elongated rail.

Brief Description of the Drawings

[0016] FIGS. 1A-1B respectively show a side elevational view and a perspective view of a portion of an in-ground swimming pool, partly in section, having a bottom surface, an adjacent/surrounding pool deck, and a vertical sidewall adjoining

therebetween, and which illustrate a self-propelled robotic pool cleaner positioned on the sidewall of the swimming pool and initiating a self-extraction procedure after completing its cleaning cycle. As used herein, the term "swimming pool" includes in-ground and above-ground swimming pools, as well as hot tubs, spas, tanks, ponds, and other structures having generally vertical sidewalls terminating in a deck or other generally horizontal surface.

[0017] FIGS. 2A-2B respectively show a side elevational view and a perspective view of the pool of FIGS. 1A and IB in which the cleaner is initiating a self-ex traction procedure by extending its lateral arm assemblies beyond the deck of the swimming pool;

[0018] FIGS. 3A-3B respectively show a side elevational view and a perspective view of the pool and cleaner of FIGS. 1A and IB during the cleaner's self-ex traction procedure in which the extendible lateral arm assemblies each include an elongated rail having a proximal end slidably mounted to the sides of the cleaner and a distal end with a rotatable arm member that is rotatable over the deck of the swimming pool;

[0019] FIGS. 4A-4B respectively show a side elevational view and a perspective view of the pool and cleaner of FIGS. 1A and IB during the self-extraction procedure in which the rails are retracted such that the rotatable arm members exert a stabilizing downward force on the deck of the swimming pool to support the cleaner as it climbs up the sidewall and exits the pool;

[0020] FIGS. 5A-5B respectively show a side elevational view and a perspective view of the pool and cleaner of FIGS. 1A and IB during the self-extraction procedure in which the rotatable arm members retract rearwardly as the cleaner climbs over the deck of the swimming pool; [0021 ] FIGS. 6A-6B respectively show a side elevational view and a perspective view of the pool and cleaner of FIGS. 1A and IB during the self-extraction procedure in which the rails and the rotatable arm members are retracted after the cleaner has fully extracted itself from the swimming pool;

[0022] FIG. 7 is a front, right-side perspective view of the cleaner of FIGS. 1 A-

6B illustrating the rails and rotatable arms in their fully extended positions;

[0023] FIG. 8 is a front, right-side perspective view of the cleaner of FIGS. 1 A-

6B illustrating the rails and rotatable arms in their fully retracted positions;

[0024] FIG. 9 is a front elevational view of the cleaner of FIG. 7;

[0025] FIG. 10 is a bottom plan view of the cleaner of FIG. 7 illustrating a water inlet;

[0026] FIG. 11 is a right-side elevational view of the cleaner of FIG. 7;

[0027] FIG. 12 is a top plan view of the cleaner of FIG. 7 illustrating the left and right arm assemblies in a normally retracted state;

[0028] FIG. 13 is a cross-sectional view of the cleaner taken along section C-C of

FIG. 12 illustrating a water pump and motor assembly and the left and right arm assemblies in their retracted positions adjacent to the corresponding side plates;

[0029] FIG. 14 is a cross-sectional view of the cleaner taken along section D-D of

FIG. 12 illustrating the left and right arm assemblies in their retracted positions adjacent the corresponding side plates;

[0030] FIG. 15 is an enlarged view of the right side sliding arm assembly taken at detail "G" of FIG. 13 and illustrating the right side rail and its rotating arm in a fully retracted position;

[0031 ] FIG. 16 is an enlarged view of the right side rail motor and rail drive gear taken at detail "H" of FIG. 14 and illustrating the right rail in its fully retracted position;

[0032] FIG. 17 is a top plan view of the cleaner of FIG. 7 illustrating the left and right rails extending laterally from their respective left and right side plates of the cleaner;

[0033] FIG. 18 is a cross-sectional view of the cleaner taken along section A- A of

FIG. 17 illustrating the water pump and motor assembly and a filter assembly mounted in an interior chamber of the cleaner; [0034] FIG. 19 is a right side cross-sectional view of the left arm assembly taken along section B-B of FIG. 17 illustrating the left rail and its rotatable arm in their retracted positions;

[0035] FIG. 20 is an enlarged view taken along detail "I" of FIG. 19 illustrating a the left rail having a plurality of teeth extending along a length of the rail;

[0036] FIG. 21 is a cross-sectional view of the cleaner taken along section C-C of

FIG. 17 illustrating the left and right rails extending laterally with respect to their corresponding left and right side plates;

[0037] FIG. 22 is a cross-sectional view of the cleaner taken along section D-D of

FIG. 17 illustrating the rails extending laterally from their respective left and right side plates;

[0038] FIG. 23 is an enlarged view of the right sliding arm assembly taken along detail "G" of FIG. 21 illustrating the right rail with its rotatable arm extending laterally from the corresponding side plates;

[0039] FIG. 24 is an enlarged view of the rail motor and rail drive gear taken along detail "H" of FIG. 22 illustrating the right rail extending laterally from the right side plate of the cleaner;

[0040] FIG. 25 is a front, left-side perspective view of the cleaner illustrating an interior view of the right arm assembly of FIG. 17 in a laterally extended position relative to a right side plate of the cleaner;

[0041 ] FIG. 26 is a left-side elevational view of the right arm assembly taken along section E— E of FIG. 17 illustrating the interior view of the right arm assembly;

[0042] FIG. 27 is an enlarged front, left-side perspective view, in section, illustrating an interior view of the right arm assembly of FIG. 25 in a laterally extended position relative to a right side plate of the cleaner;

[0043] FIG. 28 is an enlarged front elevated view, in section, of the right arm assembly of FIG. 25 illustrating the right rail in a fully retracted position relative to a right side plate of the cleaner;

[0044] FIG. 29 is an enlarged front elevated view, in section, of the right arm assembly of FIG. 25 illustrating the right rail in a laterally extended position relative to a right side plate of the cleaner; [0045] FIG. 30 is an enlarged front, left-side perspective view, in section, of the right arm assembly of FIG. 25 illustrating an interior view of the right rail and right rotatable arm;

[0046] FIGS. 31A -3 IF collectively depict various views of the cleaner of FIG. 7 illustrating the extending and pivoting the right rail and right rotatable arm thereof; and

[0047] FIGS. 32A-32M collectively depict various views of the right rotatable arm and corresponding base motor of FIGS 31 A- 3 IF.

[0048] To further facilitate an understanding of the invention, the same reference numerals have been used, where appropriate, to designate the same or similar elements that are common to the figures. Further, unless otherwise indicated, the features shown in the figures are not drawn to scale, but are shown for illustrative purposes only.

Detailed Description of the Invention

[0049] The invention is directed to a self-propelled robotic pool cleaner including one or more extendible arm assemblies to enable the cleaner to climb out of the pool, e.g., after a cleaning operation has been concluded. The cleaner can be programmed to extend one or more arms so that a distal end of the arm will exert a downward force to stabilize itself, i.e., "grasp" and hold onto the upper horizontal surface or deck at the edge of the swimming pool while the cleaner advances up the sidewall and pivotally "pulls" itself out of the pool and onto the deck. Accordingly, the self-propelled robotic pool cleaner is able to remove itself from the pool and onto the pool deck without human intervention or the assistance of an external device, e.g., a lift, cabling, transport vehicle and/or the like.

[0050] Referring now to FIGS. 1A-6B, a general description of the cleaner removal procedure is illustratively shown and described below. FIGS. 1A and IB (and similarly FIGS. 2A-6B) depict side and perspective views of a swimming pool 10, partly in section, illustrating a bottom surface 12, a sidewall 14 having a lower portion that horizontally joins the bottom surface 12 and an upper, generally vertical portion that terminates at a substantially outwardly extending or surrounding pool deck 16 in a well- known manner. The pool deck 16 can optionally have coping 17 as illustrated in the drawings. The bottom surface 12 and generally vertical sidewalls 14 form a container to hold the pool water 18. Although the pool 10 is described as an in-ground pool for purposes of illustration, such pool configuration is not to be considered limiting. For example, the swimming pool can also be an above-ground pool, tank or other water container that requires cleaning of its submerged surfaces and filtering of the water, and has a raised deck or platform surrounding the pool.

[0051 ] In FIGS. 1A and IB, an illustrative self-propelled robotic pool cleaner 20 is shown positioned in the water 18 of the pool 10. The pool cleaner 20 has one or more electric drive motors (e.g., drive motors 46) that operate to move the cleaner 20 over and clean the pool's bottom surface 12 and sidewalls 14. The pool cleaner 20 receives its electric power (and optionally communication/command signals) from an external power supply (not shown) via an electric power cable (not shown) to which it is connected. The power cable can include two or more wire conductors that are preferably encased in a foamed polymeric composition that renders the cable buoyant so that it will float on the water's surface. Alternatively, the cleaner 20 can have one or more on-board batteries to provide electric power to the cleaner and avoid the necessity of the remote power supply and electric power cable.

[0052] The self-propelled robotic cleaner 20 is equipped with a pair of arm assemblies 80 in accordance with an embodiment of the invention, and is shown positioned on the sidewall 14 near the waterline 19 after completing its cleaning cycle. Preferably, the cleaner 20 includes a programed cleaning routine that implements an extended wall climb to ensure that the cleaner has reached the waterline 19. The right and left arm assemblies 80 are shown in a fully retracted position against corresponding fixed side plates 60 of the cleaner. Each arm assembly 80 includes an elongated rail 82 having a rotatable supporting pivot arm 104 (FIG. 3A) which rotates with respect to the rail 82 between a closed position and the supporting position as shown.

[0053] Referring to FIGS. 2A and 2B, the cleaner 20 is shown with the rails 82 of each arm assembly 80 extending laterally outward from the side plates 60. Further, the rails 82 are extended in a forward direction of the longitudinal axis "L" (see FIG. 1) of the advancing cleaner 20 towards the deck 16 of the pool 10.

[0054] Referring to FIGS. 3A and 3B, each arm assembly 80 is shown with its rotatable supporting pivot arm 104 positioned at the distal end of the rail 82 and rotated generally normal to the longitudinal axis L of the cleaner and generally parallel to the pool deck. The rotating arms 104 are extended and rotated after the rails 82 are fully extended laterally and moved in a forward direction a distance above the height of the pool deck 16 to thereby provide sufficient clearance to enable the rotatable arms 104 to pivot/rotate approximately ninety degrees and extend horizontally over the deck 16. Once the rotatable arms 104 are extended horizontally over the deck 16, i.e., substantially normal to the longitudinal axis L of the cleaner 20, the rails 82 begin to retract until the rotatable supporting pivot arms 104 contact the deck 16 and thereby provide sufficient support to the cleaner 20 as it advances up the sidewall 14 of the pool 10.

[0055] Referring to FIGS. 4 A and 4B, the cleaner 20 continues to advance up the sidewall 14 of the pool 10, the rotatable supporting pivot arms 104 remain in contact with, and continue to exert a downward force on the deck 16 to thereby support the cleaner 10. As the tracks of the cleaner 20 continue to move the cleaner up the sidewall 14, the rails 82 also continue to retract a direction opposite to the direction of movement of the cleaner 10. To maintain the constant downward force on the deck 16, the rate of retraction of the arm assemblies 80 is greater than or equal to the rate at which the cleaner 20 advances up the sidewall 14 of the pool. As shown in FIGS. 4A and 4B, the rotatable arms 104 extend substantially normal from the sliding arms 80 a predetermined length to provide continuous support for the cleaner 20 while the cleaner pivotally rotates onto the deck 16 and/or the horizontal/extension of the coping portion 17 of the deck 16.

[0056] Referring to FIGS. 5 A and 5B, the cleaner 20 is shown advancing over the coping portion 17 and the rails 82 are fully retracted in the direction of the longitudinal axis of the cleaner 20. As the cleaner 20 traverses the coping 17 of the deck 16, the rotatable supporting pivot arms 104 also begin to retract, i.e. rotate toward the rear of the housing and toward the rails 82, while continuing to provide support for the cleaner on the deck 16.

[0057] Referring to FIGS. 6A and 6B, the cleaner 20 has illustratively emerged from the swimming pool 10 and is in its normally upright position on the deck 16. The rotatable arms 104 are fully retracted back into the rails 82 and the arm assemblies 80 move laterally into the corresponding channels 64 of the side plates 60 on the cleaner 20. Accordingly, the cleaner 20 includes one or more arm assemblies 80 that automatically extend and retract so that the cleaner 20 can extract itself from the pool 10 after the cleaning operation is completed.

[0058] The arm assemblies 80 include one or more drive motors 66, 108 that extend and retract the various arm components and which are preferably controlled by a controller (not shown) which can be mounted onboard the cleaner 20 or remotely with the power supply (not shown). The controller includes a microcontroller and memory/logic circuitry for operating the arm assemblies in accordance with a cleaning operation program. Once the cleaning operation is completed, an extraction routine/program that is stored in the memory of the controller is executed by the microcontroller to self-extract the cleaner from the pool. The cleaner removal program can be included as a sequence at the end of a cleaning program or as a separate program that is executable upon completion of the cleaning program. The cleaner removal program can also include programing that moves the cleaner 20 to a predetermined position on or away from the periphery of the pool deck 16 where it can be parked and/or stored for later use.

[0059] Referring now to FIGS. 7-14, an illustrative self-propelled robotic pool cleaner 20 that is suitable for implementing the method and system of the present invention is shown. The pool cleaner 20 includes a housing 24 having a bottom portion or base 26 and an upper portion 24 which can form or include a cover over the bottom portion 26. Referring to FIG. 13, the bottom portion 26 and upper portion or cover 24 collectively define an interior chamber 30 in which a one or more cleaner drive motor assemblies 46, a filter 38, a pump motor 44, electronic controllers (not shown), and other well-known cleaner sub-assemblies and components are housed. The housing 22 includes a front portion, opposing rear portion and adjoining side portions including sidewalls therebetween. The front of the housing 22 can be defined by the forward direction of movement. For example, when the cleaner 20 climbs up the sidewall 14 of the pool, 10, the front portion is the leading upper portion or end of the housing 22.

[0060] The upper portion 24 and lower portion 26 can be removably fastened with one or more fasteners such as a clasp, latch, spring clip, bolt or other well-known fasteners. A gasket or other seal (not shown) can be inserted between the base 26 and cover 24 to prevent water flowing therebetween into and out of the interior chamber 30. The cover 24 can further include an access panel 28 which can be hinged, latched or otherwise fastened to the cover 24 to permit access to the interior chamber 30 and/or the filter assembly 38 for cleaning and maintenance operations. The cover 24 and base 26 are preferably made of a polymer, such as polyvinylchloride (PVC), polypropylene, among other well-known thermoplastic materials, aluminum and/or alloys thereof, and/or combinations thereof, and/or other corrosion resistant, water impermeable materials. The cleaner 20 is generally configured to be essentially neutrally buoyant when submerged in the water. The housing 22 can include ballast and/or floatation material (not shown) to achieve the desired nearly neutral buoyancy of the cleaner.

[0061 ] The cleaner 20 includes a discharge conduit or port 36 that is formed in the upper portion 24 of the housing 22 and which can be directed normally, at an acute angle, or substantially parallel with respect to the surface beneath the cleaner 20. Since the cleaner is generally neutrally buoyant, a downward thrust or force vector from a water jet discharged from the discharge port 36 serves to stabilize and maintain the cleaner 20 on the surface being cleaned, including vertical surfaces. The location and direction of the discharge conduit or port 36 with respect to the cleaner 20 and/or the surfaces of the pool is discussed for illustrative purposes only and does not form part of the invention.

[0062] The robotic pool cleaner 20 is shown equipped with rotationally-mounted supports 32 which are coupled to the housing 22 for moving and guiding the cleaner 200 over the submerged surface of the swimming pool or tank. The rotationally-mounted supports 32 are illustratively drive tracks 33 mounted over two pairs of axially mounted track wheels/pulleys (not shown), each pair of track wheels being mounted at an opposing front/rear end of the cleaner 20. A person of ordinary skill in the art will appreciate that the drive tracks 33 are not to be considered limiting for moving the cleaner 20 and are disclosed herein for illustrative purposes only. For example, the rotationally-mounted supports can be, or include brushes wheels, rollers, caster wheels and the like. As illustrated, the right side and left side tracks 33 can operate

independently to control direction and movement of the cleaner 20. For example, the right and left tracks 33 are powered and separately controlled by independent drive motors 46 and corresponding drive gears 47, as shown in FIG. 13, subject to the proces sor/controller. [0063] Referring now to FIG. 10, the cleaner 20 includes at least one water inlet port 34 formed in the base 26. In an embodiment, the bottom surface of the base 26 can include an upwardly sloped or curved portion (not shown) formed around each water inlet port 34 to help channel or otherwise direct the flow of debris and water beneath the cleaner into the water inlet port 34.

[0064] A brush assembly 40 can be provided at either or both ends of the cleaner to stir up dirt and debris from the surface of the pool. The brush assembly 40 can be an active brush assembly in which a drive mechanism (e.g., electric drive motor 46 and gear/belt assembly) causes the brush 40 to rotate about an axle 43 (See FIG. 25) extending between and driven by the track assembly of the cleaner 20. Alternatively, the brush assembly can be a passive brush which rotates due to the frictional forces with the pool surface instead of being actively driven. In yet another embodiment, the brush assembly40 is stationary and generally stirs and lifts the debris for capture by the cleaner 20.

[0065] Referring again to FIG. 13, the cleaner 20 includes a filter assembly 38 that is mounted within the interior chamber 30 over the water inlet ports 34 of the base 26. For example, the filter assembly 38 can be a filter cartridge, a basket having a mesh screen, a filter bag, filter canister, a perforated/mesh screen or any other filtering device known in the art. A cover, check valve or flap valve (not shown) can be provided over each water inlet port 34 to prevent reverse flow of the debris back into the pool 10 when the cleaner 20 is powered down.

[0066] During normal cleaning operations of the cleaner 20, the internal water pump 44 creates a low pressure environment at the water inlet 34 to draw the pool water and suspended debris through the inlet(s) 34 and flow into or through the filter assembly 38 where the suspended debris is captured and retained. The water passing through the filter medium is "filtered" water, which is expelled from the cleaner by the water pump 44 as a high-pressure water jet through the discharge conduit/port (outlet) 36. The high pressure water jet at the outlet 36 and low pressure environment at the inlet 34 provide the necessary forces to help maintain the cleaner 20 on the pool surface beneath the cleaner. Although the discharge port 36 is shown as being directed normal (vertical) with respect to the (horizontal) base 26 of or surface beneath the cleaner 20, such orientation of the discharge port or conduit 36 is not considered limiting. For example, the discharge conduit or port 36 can be positioned at an acute angle with respect to the base 26 of or surface beneath the cleaner 20 such that the high-pressure water jet can also propel the cleaner 20 in a forward direction.

[0067] Referring now to FIGS. 7, 8 and 25-29, the housing 22 further includes opposing (i.e., left and right) side plates 60 which form a portion of the external sidewalls of the cleaner 20. The side plates 60 as shown are oval in shape to illustratively conform to the general configuration of the drive tracks 33, although the shape of the side plates (and drive tracks 33) is not considered limiting. The side plates 60 are affixed to interior sidewall portions 23 or other interior support structures provided in the interior chamber 30 by mounting bosses 62, although other fasteners can be implemented. In the illustrative embodiment shown in FIGS. 25-30, the right and left side plates 60 are each formed by spaced-apart upper and lower side plate sections 67 and 69. The side plate sections 67, 69 are attached to the interior sidewall 23 formed by the upper housing portion 24 and the lower housing portion 26, and are arranged with spacing therebetween to form an elongated channel 64, which extends horizontally in the direction of the longitudinal axis L on each side of the cleaner 20. The side plate channels 64 are configured to receive, support, and engage with a corresponding movable arm assembly 80.

[0068] Referring now to FIG. 7, the cleaner 20 preferably includes two arm assemblies 80 that can selectively be extended laterally and in a forward direction from the channels 64. The drawings illustrate a left arm assembly and a right arm assembly, although the number of arm assemblies 80 is not considered limiting. For sake of brevity, the arm assemblies 80 are described in terms of a single arm assembly (e.g., the right arm assembly), and it will be understood that the description thereof is similarly applicable to the other, i.e., left arm assembly. In an embodiment, the single are assembly can be positioned centrally or in an off-center position for longitudinal movement.

[0069] Referring now to FIGS. 25-30, each arm assembly 80 includes an elongated rail 82 that is mounted in the channel 64 formed between the upper and lower side plate sections 67 and 69. The elongated rail 82 preferably includes a substantially C- shaped cross-section formed by a substantially planar vertical sidewall 84 with inwardly directed upper and lower walls 86 and 88 extending substantially normal from top and bottom edges of the sidewall 84. The upper rail wall 86 terminates at a flange 92 extending upwardly and substantially parallel to the sidewall 84. Similarly, the lower rail wall 88 terminates at a flange 94 extending downwardly and substantially parallel to the sidewall 84. The upwardly and downwardly extending flanges 92 and 94 selectively interface with corresponding upper and lower inwardly extending flanges 63 and 65 of the upper and lower side plate sections 67 and 69, as illustratively shown and discussed below in further detail with reference to FIGS. 27-29.

[0070] Referring now to FIGS. 8, 12, 14, 16 and 28, the right side rail 82 is positioned in the channel 64 and its exterior surface is substantially aligned or flush with the exterior surface of the side plate 60. The movement and positioning of the rail 82 within the channel 64 of the side plate 60 is controlled by a rail motor 66, as illustratively shown in FIGS. 14, 16 and 25-27. The rail motor 66 is fixedly attached to a forward interior portion of the side plate 60 (e.g., upper side plate section 67) and facilitates lateral movement of the rail 82 in the channel 64 relative to the interior sidewall 23 and the side plate 60, as well as extends the rail 82 in forward/reverse directions within the channel 64. A person of ordinary skill in the art will appreciate that the rail motor 66 can alternatively be fixedly attached to the sidewall 23 of the housing 22 to facilitate lateral and longitudinal directional movement of the rail in the channel 64 relative to the side plate 60.

[0071 ] The rails 82 and side plates 60 are dimensioned and configured to minimize drag as the cleaner 20 moves through the water and to avoid damage from possible impact with objects in the pool, e.g., ladders. Other shapes and configurations of extruded or stamped metal and/or engineered polymers can be employed in the construction of the components described.

[0072] Referring to FIGS. 16 and 28, the rail motor 66 includes a rotatable drive shaft or piston 68 having distal end terminating with a fixedly attached rail drive gear 70. In one embodiment, the rail motor 66 is a DC stepper motor, although such type of motor is not considered limiting. In a normally retracted position of the arm assembly 80, the rail motor 66 is powered off and the shaft/piston 68 is extended a predetermined distance such that the exterior surface of the rail 82 is substantially in alignment or flush with the exterior surface of the side plate 60. The rail drive gear 70 includes a circular toothed portion 73 having opposing circular plates 71, which extend/radiate outwardly in a direction normal to the drive shaft 68. The circular plates 71 are spaced apart a distance that corresponds to the thickness of the upper rail flange 63. The circular plates 71 form a pair of flanges having an outer diameter that is greater than the outer diameter of the toothed gear portion 73 to facilitate lateral movement of the rail 82 inwardly and outwardly with respect to the side plate 60, as well as minimize slippage with respect to the rail teeth 91. In particular, the teeth 73 of the rail drive gear 70 interface with a row of rail teeth 91 formed on the upper rail flange 92, as illustratively shown in FIGS. 19, 20 and 26-28.

[0073] Referring to FIGS. 7, 17, 21-24, 25-29, the rail drive motor 66 selectively controls the movement of the elongated rail 82 in the lateral direction with respect to the side plate 60 prior to being extended longitudinally in the forward direction or advancing of the cleaner. Although a single rail drive motor 66 is illustratively shown and discussed, a person skilled in the art will appreciate that two electric drive motors can be utilized, one of which extends the rail laterally and the other of which extends the rail in the longitudinal direction. The controller directs the operation of the motor or motors.

[0074] FIG. 7 illustrates the arm assemblies 80 in a fully extended configuration.

The top plan view of FIG. 17 and cross-sectional views of FIGS. 21-24 illustrate that the arm assemblies 80 are first extended laterally outward away from the adjacent side plate 60 prior to being extended longitudinally in the forward direction. The arm assemblies 80 are initially extended laterally to provide a gap 61 (FIG. 27) between the respective side plates 60 and the rails 80, illustratively in the range of approximately one to four centimeters, so that the rotatable arms 104 can be rotated and pass through the gaps 61 unimpeded to a position that is substantially normal to the rails 82, as discussed below in further detail with respect to FIGS. 26-29.

[0075] Referring now to FIG. 28, as the rail motor shaft 68 moves to its fully extended position, it causes the attached gear 70 to move (e.g., pushes) the interfacing upper flange 92 of the rail 82 laterally (i.e., inwardly) towards the interior sidewall portions 23 within the channel 64. The distance the rail 82 moves laterally is based on the length and positioning of the rail motor shaft 68 and its rail drive gear 70.

[0076] Alternatively and as illustrated in FIGS. 27 and 29, as the rail motor shaft/piston 68 moves to its fully retracted position, the rail drive gear 70 moves (e.g., pulls) the interfacing upper flange 92 of the rail 82 laterally (i.e., outwardly) away from the interior sidewall portions 23 within the channel 64. The distance the rail 82 is laterally moved is based on the length and positioning of the rail motor shaft 68 and the length of the side plate flanges 63 and 65. For example, the side plate flanges 63 and 65 can extend inwardly a predetermined distance so that when the rail 82 is moved laterally and the upper and lower rail flanges 92 and 94, respectively, contact the side plate flanges 63 and 65, the rail 82 is prevented from further outward lateral movement within the channel 64 with respect to the interior sidewall portions 23 and the side plate 60.

[0077] Once the arm assembly 80 is extended laterally from the channel 64 as shown in FIG. 29, the rail drive motor 66 rotates the shaft 68 and gear 70 in a first rotational direction (e.g., clockwise) so that the gear teeth 73 rotatably mesh with the rail teeth 91 along the upper rail flange 92 to move the rail 82 in the forward direction that is substantially parallel to the longitudinal axis L. To retract the rail 82, the rail motor 66 rotates the shaft 68 and rail gear 70 in the opposite direction (i.e., counter-clockwise in this example) to thereby move the rail 82 in the rearward direction. The rail drive motor 66 and gear 70 are preferably positioned proximate the front portion of the cleaner housing 22 to maximize the length in which the rail 82 can be extended from the side plate channel 64, as illustratively shown in FIGS. 19, 25-27.

[0078] Referring now to FIG. 30, each arm assembly 80 includes a rotatable arm assembly 102, which can be selectively moved along the interior surface 85 of and to the distal end of the corresponding rail 82. The rotatable arm assembly 102 includes an elongated supporting pivot arm 104, which can be pivoted/rotated about an axis normal to the longitudinal axis of the rail to a position to support for the cleaner 20 on the pool deck 16 as the cleaner is positioned over the sidewall, for example, while exiting the pool 10. The rotatable arm assembly 102 generally includes a base 106, an arm drive motor 108, and the elongated supporting pivot arm 104. The base 106 is slidably inserted and retained between an upper groove 96 and a lower groove 98 extending longitudinally along the interior surface 85 of the rail 82. The lower groove 98 of the rail 82 is configured to support and retain the lower end of the base 106, while the upper groove 96 includes a plurality of contiguous teeth 99 extending longitudinally therein and is configured to interface with an upper end of the base 106. More specifically, the arm drive motor 108 is fixedly attached to the base 106, in which the elongated arm 104 is rotatably attached at a first (proximal) end to the motor 108, and the opposing (distal) end of the elongated supporting pivot arm 104 is free to be pivoted/rotated at least ninety degrees with respect to the rail 82. A person of ordinary skill in the art will appreciate that the plurality of contiguous teeth 99 could alternatively be provided along the lower groove 98 while the upper grove 98 is configured to support and retain the upper end of the base 106.

[0079] Referring now to FIGS. 30-32, the extension and rotation of the rotatable supporting pivot arm 104 is illustratively shown. In FIGS. 30 and 3 IB, the rotatable arm assembly 102 is positioned rearwardly along the rail 82 and the arm drive motor 108 includes a gear 111 that rotatably meshes with the teeth 99 of the upper groove 96 of the rail 82. As the arm drive motor 108 rotates the gear 111, the entire rotatable arm assembly 102, i.e., the base 106, arm drive motor 108 and rotatable arm 104, moves linearly in a forward direction between the upper and lower grooves 96 and 98 to the distal end of the elongated rail 82, as shown in FIG. 31C. The forward end of the elongated rail 82 includes a fixedly attached stop or boss 112 which extends normally, i.e., inwardly with respect to the rail in a direction towards the cleaner wall 23. The boss 112 moves with the forward end as the rail 82 is extended and retracted from the cleaner 20. The rotatatable supporting pivot arm 104 is configured to slidably engage with the fixed boss 112 as the supporting pivot arm 104 is being extended forward. The fixed positioning of the boss 112 on the rail 82 causes the rotatable supporting pivot arm 104 to pivot, i.e., rotate a predetermined amount, e.g., approximately ninety degrees when fully extended forward with respect to the elongated rail 82. Although the rotatable supporting pivot arm 104 is discussed in terms of pivoting to or about the boss 112, it will be appreciated that a second drive motor could be utilized to rotate the rotatable arm 104 with respect to the rail 82. [0080] Referring now to FIGS. 32A-32M, the rotatable supporting pivot arm 104 includes an elongated forward portion 120 and a rearward portion 122, which has an interior side that is rotatably coupled to the arm drive motor 108. In a preferred embodiment, the rotatable supporting pivot arm 104 is not rotated by the drive motor 108; rather, the rearward portion 122 includes an angular shoulder 124 which is sloped rearwardly from a bottom edge of the arm 104 a predetermined angle so as to interface with the boss 112 on the elongated rail 82 to cause the rotatable supporting pivot arm 104 to pivot approximately ninety degrees as the rotatable supporting pivot arm 104 is driven to its furthest extended position on the rail 82. In FIGS. 32E, 32F, 321 and 32L, the motor 108 includes a central bore 131 which is configured to receive a fixed shaft 127 and coaxially aligned planar disk portion 126 that are provided on the interior rearward portion 122 of the rotatable arm 104. The shaft 127 is formed on and extends outwardly from planar disk portion 126, and has sufficient length for capture by the bore 131, preferably in a snap-fit relation, which allows the arm 104 to rotate freely about a central axis of the shaft 127. The planar disk portion 126 circumscribes the shaft 127 and includes a pair of outwardly extending shoulders 128 which are spaced apart

approximately ninety degrees about the circumference of the disk portion 126, as best illustrated in FIG. 32D.

[0081 ] Referring to FIGS. 32D, 321, 32L, and 32M, the disk portion 126 is configured to interface with the exterior side of the motor housing 108. In particular, the motor housing 108 includes a pair of stops 134, e.g., one of which is positioned laterally on either side of the motor housing 108 in an arrangement spaced-apart from each other. As the shaft 127 of the rearward arm portion 122 is rotated in a first direction, e.g., clockwise, the disk 126 also rotates until one of the outwardly extending shoulders 128 contacts a corresponding stop boss 134, which prevents the arm 104 from being rotated any further (e.g., in the clockwise direction). Similarly, when the rearward portion 122 is rotated in an opposite direction, e.g., counter-clockwise, the shaft 127 and disk 126 rotate together until the other outwardly extending shoulder 128 contacts the other stop boss 134, which prevents the arm 104 from being rotated any further (e.g., in the counterclockwise direction). Accordingly, since the stops 134 are preferably spaced one- hundred and eighty degrees apart, while the disk shoulders 128 are spaced ninety degrees apart, the rotatable arm can rotate ninety degrees. A person of ordinary skill in the art will appreciate that the positioning of the stops 134 and/or disk shoulders 128 are not considered limiting, as other positions and spacings can be implemented to increase or decrease the rotational movement of the rotatable supporting pivot arm 104 with respect to the elongated rail 82.

[0082] Referring again to FIGS. 32D, 321, 32L, and 32M, a retaining or locking spring 130 can be provided with a suitable spring coefficient to secure the rotatable supporting pivot arm 104 in its normally parallel or fully rotated (vertical) position with respect to the elongated rail 82. The locking spring 130 is illustratively mounted at a lower portion of the exterior side of the motor housing 108, midway between the stops 134, although such position is not considered limiting. When the rotatable supporting pivot arm 104 is rotated a height above and extends over the pool deck 16, the rotatable arm 104 will maintain its ninety degree positioning relative to the elongated rail 82. Similarly, when the rotatable supporting pivot arm 104 is retracted in and/or moving longitudinally relative to the elongated rail 82, the locking spring 130 maintains the arm 104 in its parallel positioning to thereby avoid undesirable rotational/lateral movement with respect to the rail 82. The locking spring 130 is disengaged from the disk shoulders 134 when the arm 104 pivots against the rail boss 112, or when the arm 104 is being retracted to return to its parallel orientation with respect to the rail 82.

[0083] Referring now to FIG. 3A, and 3 lC-3 IF, the length of the rotatable supporting pivot arm 104 is greater than the height of the rail 82 as measured from the surface beneath the cleaner 20. After the base 106 and arm drive motor 108 of the rotatable arm assembly 102 have been extended vertically a sufficient height above the edge of the pool deck 16, the distal end of the rotatable supporting pivot arm 104 has sufficient clearance to be pivoted/rotated to a position approximately ninety degrees with respect to the rail 82 and extends substantially parallel above the deck 16 of the pool 10 where the cleaner 20 will exit. The rotatable supporting pivot arms 104 have a length sufficient to make contact with the deck 16 and support the size and weight of the cleaner 20 as it advances out of the pool, even if the deck 16 has a projecting coping 17.

Optionally, the bottom surface of the rotatable supporting pivot arm 104 that contacts the pool deck 16 can include a high-friction surface, i.e., textured surface or separate anti-slip material to prevent slippage. For example, the bottom surface of the rotatable arm 104 can include anti- skid/slippage tape or pads or other waterproof frictional surface materials to improve support and reduce movement after contact.

[0084] As noted above, the movement and rotation of the rotatable arm assembly

102 is preferably controlled by a controller, which can be mounted on-board the cleaner 20 or remotely with the external power supply (not shown). In an embodiment, a timing program initiates movement and rotation of the rotatable arm 104. In another

embodiment, location sensors can be implemented that transmits signals to the controller, which in turn sends command signals to activate the motors 66, 108 to extend the rail 82 and/or the rotatable arm 104. For example, a light sensor, float or electro-mechanical switch/circuit can be provided at the forward end of the rail 82 to send a signal to the controller or directly to the arm drive motor 108 to initiate the rotation of the rotatable arm 104 when the end of the cleaner is above the waterline. As well, an air sensor can be provided to detect the amount of air drawn into the chamber by the inlet 34 as a result of the cleaner 20 reaching the waterline 19 of the pool. The location of the

sensor/switch/circuit is not considered limiting as one or more such devices can be provided on the side plates 60, the rails 82 or other locations on the cleaner 20. A person of ordinary skill in the art will appreciate that other software programs, sensors, detection circuits, and/or a combination thereof can be implemented to control the time and/or distance the rails 82 are extended/retracted and the distance or degrees of rotation that the rotatable arms 102 are pivoted relative to their respective rails 82.

[0085] Although the cleaner is described as having the arm assemblies with rails

82 that extend in a forward direction along the longitudinal axis of the cleaner, such direction of movement is not considered limiting. In an alternative embodiment, each arm assembly could be configured to rotate along an axis which is transverse (normal) to the longitudinal axis, i.e., up and down when the cleaner is positioned upright on the bottom surface 12 of the pool. In one embodiment, each arm assembly is driven by an electric motor to rotate about the transverse axis of the cleaner. Each arm assembly includes a proximate end rotatably attached to the cleaner and a distal free end. The distal free end includes a fixedly or rotatably attached protruding or extendable support member that extends or is rotatably extendable outwardly in a direction substantially normal to the arm assembly. When the cleaner is on the sidewall of the pool proximate the waterline, each arm assembly is rotated about its transverse axis such that the support member will extend over the deck of the pool. The cleaner will then retract the arm assemblies in a manner described above with respect to FIGS. 1-6 so that the support member will support the cleaner as it advances further up the sidewall and onto the pool deck.

[0086] While the foregoing is directed to various embodiments of the present invention, other and further embodiments and advantages of the invention will be apparent to those of ordinary skill in the art from this description and without departing from the scope of the invention, which is to be determined by the claims that follow.

Claims

What is claimed is:

1. A method of extracting a self-propelled robotic pool cleaner from a swimming pool, the robotic pool cleaner configured to ascend a generally vertical sidewall of the swimming pool, the cleaner comprising a housing including a front end and an upper portion disposed over a lower portion to define an interior chamber, the lower portion including a water inlet and the housing having a water discharge port for discharging filtered water, rotationally-mounted supports for supporting and guiding the cleaner on a pool surface, a filter assembly for filtering water drawn through the water inlet, and an electric motor mounted in the interior chamber and configured to move the cleaner on the pool surface, the method comprising the steps of:

advancing the cleaner to ascend the sidewall of the pool and generating a first signal when a portion of the front end of the cleaner is in proximity of the waterline on the sidewall of the pool;

extending a first arm assembly a predetermined distance from the front end of the housing in response to the first signal; and

providing a support member from the first arm assembly to a position above the deck, the support member being configured to support the cleaner directly from a deck surface of the pool.

2. The method of claim 1, wherein the step of extending the first arm assembly comprises extending a distal end of said first arm assembly beyond the waterline of the pool.

3. The method of claim 1, further comprising:

positioning the support member over the deck surface; and

retracting the first arm assembly while maintaining the support member at its position over the deck surface to thereby provide support for the cleaner along the sidewall.

4. The method of claim 1, wherein said step of extending the first arm assembly further comprises extending the first arm assembly laterally outward from a side portion of the cleaner prior to extending the first arm assembly beyond the front end of the housing.

5. The method of claim 1, wherein said step of providing a support member comprises positioning a second arm member from the first arm assembly in a direction towards the sidewall of the pool.

6. The method of claim 5, wherein said step of positioning the second arm member comprises the steps of:

moving the second arm member relative to the first arm assembly in the direction of the advancing cleaner; and

rotating the second arm member from the first arm assembly over the deck surface about the pool.

7. The method of claim 6, further comprising:

retracting the first arm assembly in a rearward direction; and

maintaining the second arm member over the deck surface.

8. The method of claim 7 further comprising the steps of:

rotating one or more of the rotatably-mounted supports to ascend the sidewall of the pool;

maintaining, by the second arm member, a downwardly directed force on the deck surface until the cleaner is extracted from the pool; and

retracting the first arm assembly and second arm member once the cleaner is extracted from the pool.

9. The method of claim 8 further comprising the step of moving the cleaner to a predetermined location outside of the pool.

10. The method of claim 1 further comprising performing a pool cleaning operation on a bottom surface of the swimming pool prior to the step of causing the cleaner to ascend a sidewall of the pool.

11. A robotic pool cleaner for cleaning a swimming pool having a bottom surface, a sidewall having a lower portion adjoining at the bottom surface of the pool and an upper portion terminating at a deck extending generally horizontally about the pool, the cleaner comprising:

a housing including an upper portion disposed over a lower portion to define an interior chamber, the lower portion including a water inlet, and a water discharge port in the housing for discharging filtered water;

rotationally-mounted supports for supporting and guiding the cleaner on the pool surface;

a filter assembly for filtering water drawn through the water inlet;

an electric motor mounted in the interior chamber and configured to move the cleaner on a pool surface; and

an arm assembly including an extendible and retractable first arm assembly having a distal end which is selectively extendible from the housing a predetermined distance beyond a front portion of the housing and configured to support the cleaner directly from the deck while the pool cleaner is positioned on the sidewall of the swimming pool.

12. The pool cleaner of claim 11, wherein the housing has a longitudinal axis that is substantially normal to the front portion, and the extendible arm assembly is configured for movement normal to the longitudinal axis.

13. The pool cleaner of claim 11, wherein the housing has a longitudinal axis extending substantially normal through the front portion, and the extendible arm assembly moves in a direction of the longitudinal axis.

14. The pool cleaner of claim 11, wherein the first arm assembly comprises an elongated rail configured for movement with respect to the housing; and a first electric drive motor that controls the movement of the elongated rail.

15. The pool cleaner of claim 14, wherein the elongated rail includes a first plurality of teeth arranged along a length of the rail, the elongated rail having its longitudinal axis parallel to the longitudinal axis of the cleaner, and the first electric drive motor including a drive gear that rotatably interfaces with the first plurality of rail teeth to move the elongated rail in the direction of the longitudinal axis.

16. The pool cleaner of claim 14 further comprising a side plate mounted on a side of the housing, the side plate including an elongated channel configured to receive the extendible arm assembly; and the first electric drive motor is configured to move the first arm assembly laterally with respect to the elongated channel.

17. The pool cleaner of claim 16, further comprising a second arm member that is attached to and configured to move along the first arm assembly.

18. The pool cleaner of claim 17, wherein the second arm member is rotatably attached to a second electric drive motor which is movably mounted on the elongated rail.

19. The pool cleaner of claim 17, wherein the second arm member rotates approximately ninety degrees with respect to the first arm assembly.

20. The pool cleaner of claim 17, wherein the second arm member pivots

approximately ninety degrees with respect to the first arm assembly upon contacting a projecting stop on the elongated rail.