Abstract:
A gate having a gate arm, lock and hinge, for use with a handrail. The gate in closed position retains the structural integrity and peripheral profile of the handrail. The hinge consists of two connectors, each pivotally connected to a link by pins. The connectors pivot about the pins, enabling the gate arms to pivot through 180°. The lock includes two mating components, one component having a plug and the other having a socket for receiving the plug. A depressable button secures the plug within the socket. For use with handrails made from tubing, the hinge and lock components includes stubs insertable into the tubing. All components in the closed position of the gate compactly fit together and are shaped to provide peripheral continuity.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a divisional application of U.S. patent application Ser. No. 10/799,472, filed 11 Mar. 2004 and titled HANDRAIL GATE, HINGE AND LOCK. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to connections for tubular structures suitable for use as handrails, and more particularly to a hinge and lock that can be attached to a standard handrail to form, together with an arm in the form of a short tubular rail component, a pivotally openable gate that opens and closes the handrail where it is necessary to have a closeable access through the handrail.  
       BACKGROUND OF THE INVENTION  
       [0003]     Usually, handrails consist of horizontally and vertically arranged and connected metal hollow tubes of a selected cross-section, frequently circular. The handrails may be supported on a wall by horizontal mounting posts or may be supported from a floor by posts or stanchions, which are spaced from one another. The stanchions and wall mounting posts are interconnected by lengths of generally horizontal hollow tubing constituting the handrail, but the handrail may also be inclined or vertical along staircases or ladders. Handrails are installed to improve the safety of a specific site and to serve as a support in walking and climbing. In many industrial and civil buildings, handrails are an indispensable installation required by safety regulations.  
         [0004]     In some places, it is necessary to make available an opening in the handrail to enable access to an area on the other side of the handrail. In many cases, those openings are simply left free as they do not need to be further secured (for example, when a handrail along a sidewalk is discontinued and restarted again to create an opening for accessing a crosswalk). In other sites, however, such openings reduce the safety of the installation, particularly where a handrail separates two areas situated at different levels. In those cases, it is desirable to secure the opening by creating some barrier or gate so the handrail constantly serves its safety purpose in its full length, but can be opened when needed.  
         [0005]     Such gates within handrails can be commonly found in many manufacturing buildings, in the construction industry and in the marine industry, of which the field of recreational yachting is important. When an opening in the handrail is essential for a staircase, construction elevator, permanent ladder, or for boarding a vessel, some previous rather unsatisfactory designs for an openable section of the handrail that would maintain the structural integrity of the handrail have been proposed. It is desirable that any gate when closed, form an essentially uninterrupted continuum with the adjoining portions of the handrail, so that one&#39;s hand can pass along the gate and adjoining railing without impediment, and so that little or no risk of catching a glove or a sleeve occurs when gripping the railing in the gate portion or adjoining portions. It is further desirable that the gate be secure when closed. It is further desirable that all connecting parts, such as hinges, clasps and locks, be simple, reliable, easily manufactured, and strong enough for the purpose. Unfortunately, previously known gate arrangements have fallen short of one or more of these objectives.  
         [0006]     In the industry, closing of a gate providing a temporarily open section of a handrail is typically achieved by mounting a simple hinge at one side of the gate bar or tube. The hinge connects one end of the stationary handrail with a sectional pivoting arm constituting the gate bar or tube, usually moving in a ninety degree angle. The arm is long enough to reach the other side of the temporary opening in the handrail, where it is usually received by a mating saddle-type receptacle attached to a horizontal part of the adjoining stationary handrail. Because the closed pivoting arm is not secured or locked by any means, but simply rests in the saddle and can be accidentally opened by bumping into it from the bottom, the gate constitutes a potentially hazardous section of the handrail. In addition, the hinge attachment, which represents the only means of permanent connection of the arm, can be easily damaged when a force is applied to the closed pivoting arm from its side.  
         [0007]     To prevent accidental opening of such a conventional gate, holes are often drilled through the pivoting arm and through the handrail saddle, and removable bolts or pins are inserted into the holes to ensure that the closed arm does not open by accident nor move when a generally horizontal force is applied to it. However, obtrusive elements, such as exposed bolt heads and pins, reduce the overall safety of the handrail, as they can cause hand injuries when a person suddenly grips the handrail. Accordingly, although the conventional design of the mountable pivoting arm is advantageous to a limited extent, the methods of attachment and locking of the arm to the stationary handrail present potential opportunities for improvement.  
         [0008]     For marine use, and typically in the construction of handrails for recreational yachts and the like, openings in the handrails, if secured at all, are commonly secured by mounting a stainless steel chain and hook, or a plastic coated stainless steel wire cable and hook, to stanchions or posts or terminating stationary rail elements at the ends of the opening. Alternatively, movable wooden handrail gates with protruding conventional hinges and expensive hardware may span the opening. Devices such as cables or chains do not retain the structural integrity of the boat handrail and are not safe in harsh weather conditions. Additionally, for yachting use, the overall aesthetic appearance of the handrail structure is an important issue, and current designs of hook and cable do not entirely satisfy the expected demands of boat owners for aesthetically pleasing designs.  
         [0009]     Therefore, despite the obvious need for a safe and convenient handrail gate design, there has not heretofore been any completely satisfactory solution to the problem of providing a simple gate section in the handrail that would retain the structural integrity of the original handrail and at the same time be both aesthetically pleasing and safe.  
         [0010]     It is apparent that the objectives of structural integrity and aesthetic appeal can be met by providing a handrail gate having the same cross-section as the stationary portion of the handrail. The problem is to provide a hinge on one end of the gate and a lock at the other end of the gate that maintain a uniform cross-section throughout the handrail when the gate is closed, even at points of connection. Such hinge and lock should be inexpensive, safe, easy to manufacture, install and use, aesthetically pleasing, durable and solid enough to resist occasional impacts accidentally caused by users without being displaced or sufficiently damaged to interfere with satisfactory operation.  
       SUMMARY OF THE INVENTION  
       [0011]     An object of the present invention is to provide a combination of a hinge and lock for interconnecting a standard tubular handrail (typically but not necessarily made of round tubing) with a pivoting arm to form a gate within the handrail that retains the structural integrity of the original handrail, and is safe and aesthetically pleasing.  
         [0012]     Another object of the present invention is to provide a hinge and lock mountable on or connectable to a standard tubular handrail and on or to a mating pivotable gate arm, that are easy to manufacture, install and use, and that are at the same time durable and reliable.  
         [0013]     Another object of the present invention is to provide a hinge as aforesaid that enables pivoting of the gate arm through an angle up to about 180°.  
         [0014]     Another object of the present invention is to provide a gate lock as aforesaid that when in the closed position resists longitudinal tensional forces across the gate opening.  
         [0015]     The hinge and the lock of the present invention can be used independently of one another.  
         [0016]     The hinge and the lock of the present invention are substitutes for the hinge and lock described in Applicant&#39;s previously filed Canadian patent application Ser. No. 2,314,839, filed on 2 Aug. 2000. For convenience of description, some of the content of Applicant&#39;s previously filed Canadian patent application is repeated in this application.  
         [0017]     The hinge and lock may be installed and used in various orientations, but for ease of explanation in this specification, including the claims, the hinge and lock are referred to as if they are in the closed position when installed on a horizontal handrail. More particularly, the following words have the following meanings: 
    1. “longitudinal” refers to movement and directions substantially parallel to the longitudinal axis of the handrail and gate arm when the gate arm is in the closed position; and     2. “lateral” refers to side-to-side movement and directions, that is, those that are substantially horizontal and substantially perpendicular to the longitudinal axis of the handrails and gate arm when the gate arm is in the closed position.    
 
         [0020]     The gate according to the invention is particularly suitable for use with an elongate handrail or the like that has one or more open gateways that need to be locked (latched) closed from time to time. Each gateway exists between two spaced terminals of the handrail, one terminal on either side of the gateway.  
         [0021]     Preferably, the gate includes a pivotable gate arm, preferably having the same profile in cross-section as the handrail, and pivotally movable from a closed locked position to a fully open position at which the gate arm lies next to the adjoining stationary handrail. Even though the gate arm itself may be substantially uniform along its length or at least longitudinally symmetrical, the two ends of the gate arm may conveniently be referred to as the gate hinge end and the gate lock end, since one end of the gate arm is fastened to a hinge for hingedly connecting the hinge end of the gate arm to one terminal, conveniently referred to as the handrail hinge terminal, and the other end of the gate arm is fastened to one component of a two-component lock. The other lock component is fastened to the other terminal of the handrail, conveniently referred to as the handrail lock terminal. The two lock components matingly engage one another as the lock end of the gate arm moves into alignment with the lock terminal of the handrail.  
         [0022]     The two lock components are respectively provided with mating components of a lock that is operative to releasably secure the gate arm to the handrail when the lock end of the gate arm is aligned with the neighbouring lock terminal of the handrail, and the mating lock components have come into engagement with one another. A release means such as a depressable projecting button is provided for releasing the two lock components from one another after they have locked together.  
         [0023]     The lengths of the gate arm and of the hinge and lock components are selected so as to provide a substantially uninterrupted continuum of the entire handrail structure (including the gate arm), when the gate arm is in the closed position. To optimize the structural continuity, the peripheral profile of the hinge and of the lock components are selected to be identical to or at least to merge with the peripheral profile of the gate arm and the handrail.  
         [0024]     Handrails are typically made of hollow tubing. Round tubing is the most common and generally the least expensive to manufacture. According to the preferred embodiment of the invention, the hinge and lock components are provided with stubs insertable into the tubing, preferably in a tight fit or at least a snug fit. Auxiliary securing means are also preferably provided to fasten the hinge and lock elements in place during normal use.  
         [0025]     In accordance with the present invention, there is also provided a lock having two mating elements referred to herein as the active lock component and the passive lock component. The active lock component has a plug that projects substantially perpendicular to the longitudinal axis of the handrail or gate arm, as the case may be, to which it is attached when the active lock component is installed. The passive lock component has a socket sized and shaped for receiving the plug. The socket has longitudinally-extending side walls so as to impede lateral movement of the active lock component relative to the passive lock component when the plug is in the socket; and a laterally-extending end wall so as to impede longitudinal movement of the active lock component relative to the passive lock component when the plug is seated in the socket.  
         [0026]     The lock includes means for releasably securing the plug within the socket so as to releasably secure the passive and active lock components one to the other. Preferably, the means for releasably securing the plug within the socket comprises a depressable button projecting from the plug and a hole in the socket through which the button projects when the plug is seated within the socket and the active and passive lock components are in the closed position.  
         [0027]     Accordingly, the plug and socket, and button and socket, interlock so as to resist any motion of the active lock component relative to the passive lock component when the lock components are in the closed position.  
         [0028]     Preferably, the active and passive lock components include surfaces on one or both lock components configured to guide the plug and socket into proper alignment during movement of the lock components to the closed position. Preferably, these guiding surfaces include surfaces that tend to guide the lock components longitudinally such as where the disengaged lock components longitudinally overlap too much, or not enough, for proper interlocking of the plug and socket. Further, these guiding surfaces also preferably include a surface or surfaces tending to guide the lock components laterally, so as to laterally align the lock components during closing. Laterally-guiding surfaces may be desirable when there is sufficient lateral play in the gate arm to permit lateral misalignment of the lock components.  
         [0029]     Further, the laterally-guiding surfaces also preferably include a surface on the plug, or within the socket, that guides the plug within the socket during closing such that the button is pushed against a side wall of the socket so as to depress the button. This button-depressing laterally-guiding surface preferably comprises a planar surface on the side of the socket opposite the hole The planar surface is inclined relative to the plane defined by the opening and closing pivotal movement of the gate arm such that when the plug contacts the planar surface during closing the planar surface guides the plug to move simultaneously laterally towards the hole and downward, so as to depress the button and move it towards alignment with the hole.  
         [0030]     The peripheral profile of the lock components are preferably selected to be identical to, or at least to merge with, the peripheral profile of the gate arm and the handrail, when the lock components are in the closed position. When the gate arm and handrail are made from round tubing, the visible portions of the closed lock components are configured so as to combine to form a cylindrical peripheral profile of substantially the same diameter as the gate arm and handrail. Preferably the overlapping visible portions of the lock components are each semi-cylindrical. The semi-cylindrical portion of the passive lock component contains the socket and hole. The plug projects from the semi-cylindrical portion of the active lock component. The visible portions of the lock components may also each comprise a cylindrical collar, integral with the respective semi-cylindrical portion and adjoining the relevant handrail or gate arm when the relevant lock component is installed.  
         [0031]     For use with handrails and gate arms made from hollow tubing, the lock components preferably each have a stub portion for insertion into the gate lock end or the handrail lock terminal, as the case may be, preferably in a snug or tight fit, so as to attach the lock components to the handrail and gate arm.  
         [0032]     For use with handrails and gate arms made from round hollow tubing, each stub preferably is substantially cylindrical and has an external diameter the same as or slightly smaller than the internal diameter of the tubing. Preferably, each stub is hollow and is provided with circumferentially-spaced longitudinally-extending slits to permit the stub to be slightly compressed to facilitate insertion. Preferably the stub has one or more retainer wedges, each having a relatively-long gently-inclined top surface that permits easy insertion of the stub and a short end surface that forms a sharp corner with the gently-inclined surface, which sharp corner engages the inner wall of the tubing so as to resist removal of the stub. Preferably each stub is provided with bevelled or chamfered distal edges to facilitate the initial insertion of the stub into the tubing.  
         [0033]     Each stub is also preferably additionally secured within the relevant handrail or gate arm by a fastener such as a headless screw. The fastener is preferably installed by drilling a hole through the handrail or gate arm, and the relevant stub after the stub has been inserted into the handrail or gate arm. If required for the particular fastener, the hole may then be tapped with the appropriate threads and the fastener, such as a headless screw or other screw, is then screwed into position. The fastener need not be a headless screw and may be a regular machine screw with a head, a rivet or a variety of other fasteners.  
         [0034]     In accordance with the foregoing objectives, there is provided an improved hinge for hingedly connecting the handrail hinge terminal to the gate hinge end. The hinge includes two connectors and a link, each connector being separately pivotally attached to the link. Each connector is attached to the link such that each connector may pivot roughly 90° relative to the link, such that the connectors can pivot through roughly 180° relative to each other.  
         [0035]     Preferably, the link and connectors are configured such that a portion of each connector abuts the link when the gate arm to which the hinge is attached is in the closed position so as to impede pivotal movement of the gate arm in the direction opposite the opening direction. As well, a portion of each connector abuts the link when the gate arm to which the hinge is attached is pivoted to a fully open position roughly 180° from the closed position, such that the gate arm is substantially parallel to the adjoining handrail. In this way the hinge impedes pivotal movement of the gate arm beyond roughly 180° between the closed position and the fully open position. This structural arrangement lends to the hinge a motion-limiting characteristic permitting the gate arm to pivot from the closed position to the fully open position only in one general direction, usually upward. Accordingly, in the closed position, the gate arm will tend to remain coaxial with the stationary handrail, and will tend not to collapse or pivot downwardly even if it is not supported at its distal end.  
         [0036]     Preferably, the connectors are essentially identical one to the other and each comprises a clevis having two spaced-apart fingers and a web spanning the fingers at the base of the fingers, the clevis fingers defining a clevis gap, with the clevis gaps being of substantially identical widths. Preferably, the link is a generally-rectangular parallelepiped interposed between the clevis fingers of each connector and pivotally connected to each connector by a pin through aligned holes in the link and the relevant connector. The link is sized for insertion into the clevis gaps such that the width of the link is selected to be slightly less than the width of the clevis gap. Preferably, a portion of the web of each connector abuts a portion of the adjoining end of the link when the gate arm is in the closed position so as to impede pivotal movement of the gate arm in the direction opposite the opening direction. Preferably, a portion of the web of each connector abuts the upper surface of the link when the gate arm is in the fully open position so as to impede pivotal movement of the gate arm beyond roughly 180° from the closed position. Preferably, the portions of the webs and link that abut when the gate arm is in the closed position are substantially planar surfaces that are substantially perpendicular to the longitudinal axis of the gate arm and handrail. Alternatively, the link ends and webs may be configured such that the abutting surfaces are substantially parallel to, or inclined relative to, the longitudinal axis of the gate arm and handrail.  
         [0037]     Alternatively, the link may include two link devises and each connector may include a projection inserted into, and pivotally attached to, a link clevis, such that the connector projection pivots within the link clevis. Alternatively, neither the link nor the connectors may have a clevis, and the link and connectors may merely overlap side-by-side rather than a portion of one being interposed between fingers projecting from the other.  
         [0038]     The peripheral profile of the hinge is preferably selected to be identical to, or at least to merge with, the peripheral profile of the gate arm and the handrail, when the gate arm is in the closed position. Preferably the link and connectors are configured such that when the gate arm is closed, the distal ends of the devises abut each other and the top and bottom surfaces the link span the gaps defined by the fingers and the web such that the connectors and link form, to the casual observer, one seemingly-solid piece. When the gate arm and handrail are made from round tubing, the outer surfaces of the clevis fingers, and the top and bottom surfaces of the link, are curved and combine, in the closed position, to form a cylindrical peripheral profile of substantially the same diameter as the gate arm and handrail.  
         [0039]     For use with handrails and gate arms made from hollow tubing, the connectors preferably each have a stub portion, essentially identical to the lock component stub portions, for insertion into the gate hinge end or the handrail hinge terminal, as the case may be, so as to attach the connectors to the handrail and gate arm.  
         [0040]     The hinge and lock components can be conveniently manufactured so as not to have any sharp nor obtrusive parts or edges, thus permitting them to constitute an integral part of the hand railing. In order to merge visually and structurally with the rest of the handrail, the hinge and lock may be fabricated out of the same material as the handrail. For visual continuity, they may have the same surface finishing as the handrail. The hinge and lock may be made from diverse materials, such as stainless steel and aluminum.  
         [0041]     A longitudinal series of gate arms, hinges and locks can be arranged together, thereby creating the possibility of opening large handrail sections. A preferred such combination makes use of a central stanchion that is itself hinge-coupled, or otherwise releasably attached, to a bottom pedestal, permitting the entire stanchion, apart from the pedestal, to be: collapsed pivotally downwardly so as to assume a horizontal orientation, or to be removed. The stanchion receives two individually operable gates, themselves coupled by the hinge connections to tubular railings on either side of the stanchion, and locking to the stanchion. By opening both gates and collapsing the stanchion downwardly or removing the stanchion, it would be possible to create a relatively large opening in the handrail. Further, the stanchion and gate arms may be configured such that with the stanchion in its normal upright position, one gate arm may be opened, leaving the other gate arm closed.  
         [0042]     It will be clear that the gate arm need not open only vertically. The hinge and lock may be installed in a variety of orientations as desired.  
         [0043]     The present invention provides many advantages over previously known designs. It offers a simple and ingenious solution to the problem of securing handrail openings (gates). To a great extent, it retains the structural and peripheral integrity of the original handrail, it is durable and strong, and it presents few protrusions or obstructions that can cause injuries. The preferred embodiments provide constraints that prevent or limit motion of the gate arm in undesired directions.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0044]      FIG. 1  is a perspective view of a hinge and lock according to a preferred embodiment of the present invention mounted on a standard handrail shown in a closed position.  
         [0045]      FIG. 2  is a partly cross-sectional view along the line I-I in  FIG. 1  of a hinge of the type illustrated in  FIG. 1 , in the closed position.  
         [0046]      FIG. 3A  is a perspective view of the handrail hinge of  FIG. 1 , shown in a fully opened position.  
         [0047]      FIG. 3B  is a perspective view of the passive component of a lock according to a preferred embodiment of the invention mounted onto the end of the handrail opposite that shown in  FIG. 3A  and separated from the end of the handrail shown in  FIG. 3A  by the width of the gate arm. Viewing  FIGS. 3A and 3B  together, one perceives an open gateway, the gate arm being folded over onto the handrail portion to which it is connected.  
         [0048]      FIG. 4  is a view partly in cross-section along the line II-II in  FIG. 3A  of a fully opened hinge.  
         [0049]      FIG. 5  is a perspective view showing an embodiment of the active lock component of the present invention.  
         [0050]      FIG. 6  is a perspective exploded view showing the active lock component of  FIG. 6  with the parts of the depressable button.  
         [0051]      FIG. 7  is a perspective view showing an embodiment of the passive lock component of the present invention.  
         [0052]      FIG. 8  is an alternative perspective view showing the passive lock component of  FIG. 7 .  
         [0053]      FIG. 9  is a partly sectional view of the active lock component showing the parts of the depressable button.  
         [0054]      FIG. 10A  is a longitudinal sectional view of an embodiment of the passive and active lock components of the present invention showing first contact between the lock components during closing when the lock components are longitudinally misaligned so as to overlap more than required for full closure.  
         [0055]      FIG. 10B  is a lateral sectional view of the passive and active lock components shown in  FIG. 10A .  
         [0056]      FIG. 11A  is a longitudinal sectional view of the passive and active lock components shown in  FIG. 10A , showing first contact between the lock components during closing when the lock components are longitudinally misaligned so as to overlap less than required for full closure.  
         [0057]      FIG. 11B  is a lateral sectional view of the passive and active lock components shown in  FIG. 11A .  
         [0058]      FIG. 12A  is a longitudinal sectional view of the passive and active lock components shown in  FIGS. 10A and 11A , showing a position of the lock components during closing, between first contact and the fully closed position.  
         [0059]      FIG. 12B  is a lateral sectional view of the passive and active lock components shown in  FIG. 12A .  
         [0060]      FIG. 13A  is a longitudinal sectional view of the passive and active lock components shown in  FIGS. 10A, 11A  and  12 A, showing the lock components in the fully closed position.  
         [0061]      FIG. 13B  is a lateral sectional view of the passive and active lock components shown in  FIG. 13A .  
     
    
     DETAILED DESCRIPTION  
       [0062]      FIGS. 1 through 13 B show a preferred embodiment of the present invention for use with handrails made of round tubing.  FIG. 1  shows the hinge  1 , handrail  2 , gate arm  3  and lock  9  in the closed position.  
         [0063]     As shown in  FIGS. 1, 2 ,  3 A and  4 , the hinge includes a link  5  and two connectors  4 ,  6 . The two connectors are substantially identical to each other and are interchangeable. For ease of description, they are named herein according to how they are shown installed in  FIGS. 1, 3A  and  4 , being, a fixed connector  4  attached to the handrail  2  and a mobile connector  6  attached to the gate arm  3 . Each connector  4 ,  6  has a clevis  41 ,  61  (respectively) and a stub  42 ,  62  (respectively). The fixed connector clevis  41  includes two spaced-apart fingers, a first fixed finger  43  and a second fixed finger  44 , having opposed substantially-parallel planar surfaces, and a web, the fixed web  45 , spanning the fixed fingers  43 ,  44  at their bases. Likewise, the mobile connector clevis  61  includes two spaced-apart opposed fingers, a first mobile finger  63  and a second mobile finger  64 , having opposed substantially-parallel planar surfaces, and a web, the mobile web  65 , spanning the mobile fingers  43 ,  44  at their bases.  
         [0064]     The link  5  is a generally rectangular parallelepiped (with curved upper and lower surfaces, as described below). The link  5  is interposed between the fixed fingers  43 ,  44  and pivotally attached to the fixed connector clevis  41  by a pin  18  passing through aligned holes in the fixed fingers  43 ,  44  and the link  5 . Likewise, the link is interposed between the mobile fingers  63 ,  64  and pivotally attached to the mobile connector clevis  61  by a pin  18 ′ passing through aligned holes in the mobile fingers  63 ,  64  and the link  5 . The gap between the fixed fingers  43 ,  44  is substantially the same as the gap between the mobile fingers  63 ,  64 .  
         [0065]     The link  5  is sized and shaped such that, when the gate arm  3  to which the link  5  is attached is in the closed position, the link  5  substantially fills the space defined by the fingers  43 ,  44 ,  63 ,  64  and the webs  45 ,  65 , such that the upper link surface  53  and the lower link surface  54  (as shown in  FIG. 2 ) substantially visually blend with the devises  41 ,  61 . In the embodiment shown in the drawings the handrail  2  and the gate arm  3  are made of cylindrical tubing; and the devises  41 ,  61  have curved outer surfaces that closely match the external profile of the handrail  2  and the gate arm  3 , and the upper link surface  53  and lower link surface  54  are similarly curved.  
         [0066]     The link  5  and webs  45 ,  65  are configured to limit the range of pivotal movement of the hinge  1  to roughly 180°, being between the closed position in which the gate arm  3  and adjoining handrails  2  are aligned and substantially coaxial as shown in  FIG. 1 , and the fully open position in which the gate arm  3  is positioned alongside and substantially parallel to the handrail  2  as shown in  FIG. 3A . In the closed position, as shown in  FIG. 2 , a first portion of each web  45 ,  65  abuts the ends of the link  5  so as to impede downward pivoting of any of the connectors  4 ,  6  or link  5  relative to each other. In the open position, a second portion of each web  45 ,  65  abuts the upper link surface  53  so as to impede pivoting movement of the hinge  1  beyond roughly 180° from the closed position. In this way, each connector  4 ,  6  is limited to roughly 90° of pivoting movement relative to the link  5 . As shown in  FIGS. 1 and 3 A, the fingers  43 ,  44 ,  63 ,  64  have bevelled or partially curved ends so as to permit the connectors  4 ,  6  to pivot past each other during the opening and closing of the gate arm  3 .  
         [0067]     The stubs  42 ,  62  are for attaching the relevant connectors  4 ,  6  to the associated handrail  2  and gate arm  3 . In the embodiment shown in the drawings, the handrail  2  and gate arm  3  are made of cylindrical tubing. The stubs  42 ,  62  are configured for insertion into the handrail  2  and gate arm  3 . The stubs  42 ,  62  each comprise a hollow cylindrical body with an external diameter substantially the same as, or slightly less than, the internal diameter of the handrail  2  and gate arm  3 . In the embodiment shown in the drawings, each stub  42 ,  62  has four longitudinally extending slits  11  and two retainer wedges  12 . The slits  11  permit the stubs  42 ,  62  to be slightly compressed for insertion into the handrail  2  and gate arm  3 . The retainer wedges  12  have a relatively-long gently-inclined top surface that permits easy insertion of the stubs  42 ,  62 , and a short end surface that forms a sharp corner with the gently-inclined surface, which sharp corner engages the inner wall of the hand rail  2  and gate arm  3 , as the case may be, so as to resist removal of the relevant stub  42 ,  62 .  
         [0068]     Each stub  42 ,  62  is also preferably additionally secured within the relevant handrail  2  or gate arm  3  by a fastener such as a headless screw  13 , as shown in  FIG. 4 . The headless screw  13  is installed by drilling a hole through the handrail  2  or gate arm  3 , and the relevant stub  42 ,  62 , after the stub  42 ,  62  has been inserted into the handrail  2  or gate arm  3 . The hole is then tapped with the appropriate threads and the headless screw  13  is screwed into position. The headless screw  13  is preferably screwed into one of those sections of the relevant stub  42 ,  62  bounded by two slits  11  that does not have a retainer wedge  12 , so that the section of the relevant stub  42 ,  62  through which the headless screw  13  is screwed is not held away from the inner wall of the handrail  2  or gate arm  3  by a retainer wedge  12 . Generally, it is preferable for aesthetic reasons that the headless screws  13  be located on the underside of the handrail  2  and the underside of the gate arm  3 , when the gate arm  3  is in the closed position, so that the headless screws  13  are not normally visible. The fastener need not be a headless screw  13  and may be a regular machine screw with a head, a rivet or a variety of other fasteners. Alternatively, the stub may be secured within the tubing by welding, such as by spot welding at a hole drilled in the tubing.  
         [0069]     It will be clear that the connectors  4 ,  6  could be attached to the handrail  2  and gate  3  by means other than insertable stubs  42 ,  62 , such as by welding.  
         [0070]     As shown in  FIGS. 5 through 13  B, the lock  9  includes a passive lock component  7  and an active lock component  8 . The passive lock component  7  has a socket  70 . The active lock component  8  has a plug  72  for matingly engaging the socket  70 , and a radially-projecting depressable latching button  74  that engages a button hole  76  in the passive lock component  7  for securing the plug  72  within the socket  70  so as to secure the lock components  7 ,  8  one to the other. The button  74  and socket  70  should of course have mating cross-sectional configurations and dimensions, but these need not be circular. The preferred circular cross-section of each is illustrated.  
         [0071]     Each lock component  7 ,  8  includes a stub, the passive lock component stub  78  and the active lock component stub  80  as the case may be, that is in all relevant details substantially identical to the connector stubs  42 ,  62  previously described, and that may be installed in the same manner as the connector stubs  42 ,  62 .  
         [0072]     The embodiment of the lock  9  shown in the drawings is for use with handrails  2  and gate arms  3  made of round tubing; and the portions of the lock components  7 ,  8  that are visible when installed and when the gate arm  3  is in the closed position, have surfaces that closely match the external profile of the handrail  2  and gate arm  3 .  
         [0073]     In the embodiment shown in the drawings, the socket  70  is defined by an inner end wall  82 , an outer end wall  84 , a curved side wall  86 , a straight side wall  88  and a guide side wall  90 . The inner end wall  82  is substantially perpendicular to the longitudinal axis of the passive lock component  7 . The outer end wall  84  has a lower wall lip  92  that is substantially perpendicular to the longitudinal axis of the passive lock component  7 , and an upper wall lip  94  that is inclined relative to the lower wall lip  92 . The curved side wall  86  contains the button hole  76 . The curved side wall  86  adjoins the straight side wall  88 .  
         [0074]     The plug  72  has an end face  96 , an end guide face  98 , an inner face  100 , a curved side face  102 , a straight side face  104  and an inclined side face  106 . The end face  96  is substantially perpendicular to the longitudinal axis of the active lock component  8 . The end guide face  98  adjoins, and is inclined relative to, the end face  96 . The inner face  100  has a lower face lip  108  that is substantially perpendicular to the longitudinal axis of the active lock component  8 , and an upper face lip  110  that is inclined relative to the lower face lip  108 . The button  74  projects from the curved side face  102 . The curved side face  102  adjoins the straight side face  104 .  
         [0075]     As shown in  FIG. 9 , the button  74  has a button shoulder  112  contained within the button sleeve  114 . The button sleeve  114  is secured within a cavity in the active lock component  8  and is preferably a metal sleeve pressed in a tight fit into a bore in the active lock component  8 . A spring  116  within the button sleeve  114  biases the button shoulder  112  against an annular retainer  118  at the outward end of the button sleeve  114 , such that the button  74  is spring-biassed to project from the curved side face  102 . The spring  116  is selected so that the button  74  may be manually depressed.  
         [0076]      FIGS. 10A through 13B  show some of the possible positions of the passive lock component  7  and active lock component  8  relative to each other during closing of the gate arm  3 .  FIGS. 10A and 11A  show the initial contact between the passive lock component  7  and the active lock component  8  in situations where there is a slight longitudinal misalignment of the lock components  7 ,  8 , such as perhaps might be due to the gate arm  3  being the incorrect length, for example, too long in  FIG. 10A  and too short in  FIG. 11A . In  FIG. 10A , the point of first contact is between the top of the inner end wall  82  and the end guide face  98 , and as the active lock component  8  moves towards engagement with the passive lock component  7 , the incline of the end guide face  98  helps to guide the plug  72  into the correct longitudinal position to engage the socket  70 . Alternatively, as shown in  FIG. 11A , the point of first contact may be between the bottom of the lower face lip  108  and the upper wall lip  94 , and as the active lock component  8  moves towards engagement with the passive lock component  7 , the incline of the upper wall lip  94  helps to guide the plug  72  into the correct longitudinal position to engage the socket  70 .  
         [0077]     As shown in  FIG. 11B , the contact of the button  74  with the top of the curved side wall  86  tends to cause the active lock component  8  to move laterally relative to the active lock component  7 , such that further downward movement of the active lock component  8  causes the bottom of the curved side face  102  to contact the guide side wall  90 . The incline of the guide side wall  90  combined with a downward force on the active lock component  7  causes the active lock component to move both downward and laterally so as to: depress the button  74  so as to compress the spring  116  by pushing the button  74  against the curved side wall  86 ; and bring the straight side face  104  into alignment with the straight side wall  88 , as shown in  FIG. 12B . As shown in  FIG. 13B , further downward movement of the active lock component  8  brings the button hole  76  into alignment with the button  74  permitting the spring  116  to expand so as to cause the button  74  to project through the button hole  76 , thus securing the active lock component  8  to the passive lock component  7  in the closed position.  
         [0078]     In the closed position, the presence of the button  74  within the button hole  76  impedes upward movement of the active lock component  8 ; the abutting of the straight side face  104  with the straight side wall  88  and the abutting of the top of the curved side face  102  with the top of the curved side wall  86  impede lateral movement of the active lock component  8 ; and the abutting of the lower wall lip  92  with the lower face lip  108  resists longitudinal forces tending to separate the passive and active lock components  7 ,  8 .  
         [0079]     The active lock component  8  may be released from the passive lock component  7  by depressing the button  74  and moving the active lock component  8  upwards.  
         [0080]     The button  74  may be relatively small and unobtrusive, and therefore the lock  9  is particularly aesthetically appropriate for relatively small tubing, such as 2.5 cm (1″) diameter. Further, in this embodiment, the gate arm  3 , hinge  1  and lock  9  are configured to tie the handrail  2  portion on one side of the gate opening to the handrail  2  portion on the other side of the gate opening so as to resist longitudinal tensional forces tending to spread the handrails  2  on each side of the gate opening. This tying of the handrails  2  contributes to the overall strength of the handrail  2  installation and tends to cause the gate arm  3  to stay closed even if neighbouring portions of the handrail  2  are bent, such as by heavy objects or persons failing against them, or, in the case of marine applications, due to wave impact in extreme storm conditions.  
         [0081]     It will be clear that the lock  9  need not be associated with a hinge permitting the gate arm  3  to pivot through a full 180° and that various other hinges may be used with the lock  9 . Further, the gate arm  3  may be designed to telescope into the handrail  2  as long as there is sufficient play at the end of the gate arm  3  to permit the mating portions of the lock components  7 ,  8  to clear each other as the gate arm  3  is telescoped in or out. As well, the gate arm  3  may be designed to be removable, by having a lock  9  at each end, or a lock  9  at one end and some other means for releasably engaging the handrail  2  at the other end.  
         [0082]     The scope of the invention is not to be limited by the specific details described, but is to be given the full scope established by the appended claims. As used in the appended claims, the word “tubing” means a hollow bar of any suitable profile (e.g., round, rectangular, oval).