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You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
     The present invention relates to the field of engagement devices. More particularly, the invention relates to a spring actuated engagement device. 
     BACKGROUND OF THE INVENTION 
     The coupling of two elements together at inaccessible, hard to reach areas is often a laborious and time consuming task, requiring the user to access the engagement location from a distance in order to ensure that the elements will be successfully mated together. 
     It is an object of the present invention to provide an engagement device by which two elements may be mechanically coupled together or separated while a user is disposed at a distance from the engagement location. 
     It is an additional object of the present invention to provide an engagement device by which two elements are reliably coupled together. 
     Other objects and advantages of the invention will become apparent as the description proceeds. 
     SUMMARY OF THE INVENTION 
     The present invention provides a spring actuated engagement device for remotely coupling a movable member to a stationary member, comprising a fixture mountable onto a stationary member, a spring biased bar that is axially displaceable within a central recess formed within said fixture, an abutting element extending outwardly from one end of said bar for actuating said spring, at least one seating element outwardly spaced from an outer face of said fixture and longitudinally spaced from said abutting element, wherein said abutting element is configured to be axially displaced in a first direction when contacted by a first terminal edge of a movable member, allowing a second terminal edge of said movable member longitudinally spaced from said first edge to be receivable in an interspace between said at least one seating element and said outer face, and to be axially displaced in a second direction opposite to said first direction after a force that initiated said contact with said first edge is released, whereby to engage said movable member. 
     In one aspect, the fixture is rectilinear and has first and second terminal faces substantially perpendicular to the outer face, a border element being formed between said first terminal face and the central recess to limit displacement of the abutting element in the first direction. 
     In one aspect, the at least one seating element longitudinally extends from the second terminal face, allowing the movable member to be longitudinally engageable by the abutting element and a portion of said additional face adjoining the at least one seating element and to be transversally engageable by the fixture outer face and the at least one seating element. 
     In one aspect, the fixture has two side faces and further comprises a corresponding guide element outwardly and laterally protruding from each of said side faces to laterally engage the movable member. The guide element may be formed with a guiding surface for urging the movable member to a correct lateral alignment when the abutting element is being axially displaced in the first direction if said guiding surface is inadvertently contacted by a portion of the movable member. 
     As referred to herein, the abutment element is axially displaceable in a “longitudinal” direction, the side faces of the fixture are spaced in the “lateral” direction, and the outer face is spaced from the stationary member in the “transversal” direction. 
     In one aspect, a spring housing, which may longitudinally extend to the abutting element, protrudes outwardly from the bar and the spring retained within said housing is attached at one end to a base of the bar and at another end to a securing element extending outwardly from an inner face of the fixture which borders the central recess. A positioning element fitted in the base of the bar is adapted to contact an edge of an aperture formed in the inner face, to limit displacement of the bar in the second direction. 
     In one aspect, a position indicating element extends in the second direction from the abutting element to define an interspace between said position indicating element and the spring housing for positioning the movable member first edge when the abutting element is being axially displaced in the first direction. The position indicating element may be formed with an outer guiding surface for urging the movable member first edge into a correct alignment within the interspace between the position indicating element and the spring housing if the movable element is incorrectly transversally aligned. 
     In one aspect, the engagement device further comprises a locking device for preventing longitudinal displacement of the abutting element once the movable member is engaged. 
     In one aspect, the locking device is pivotally displaceable and releasably engages the border element when displaced to a locking position. 
     In one aspect, the first terminal face transversally extends inwardly from the outer face and is sufficiently thicker than the side faces to receive a pin in an aperture formed therein, the locking device being pivotable about said pin. 
     The present invention is also directed to a locking device for preventing displacement of an actuator, comprising first and second spaced and substantially mutually parallel elements, an end wall extending between said first and second elements, a handle spaced from said end wall, and a pin extending from a terminal portion of said first element into an aperture formed in a fixture and about which said locking device is pivotally displaceable, wherein, when said locking device is set to a locked condition, said first and second elements are sized to engage a border element of said fixture therebetween and said second element is positioned in abutment with said actuator to prevent actuator displacement in a direction between said first and second elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of an engagement device according to one embodiment of the present invention, shown in an unlocked condition; 
         FIG. 2  is a rear view of the engagement device of  FIG. 1 , shown in a locked condition; 
         FIG. 3  is a bottom view of the engagement device of  FIG. 1 , shown in a locked condition; 
         FIG. 4  is a rear view of the engagement device of  FIG. 1 , shown in an unlocked condition; 
         FIG. 5  is a perspective view of the engagement device of  FIG. 1 , shown in a locked condition; 
         FIG. 6  is a side view of the engagement device of  FIG. 1 , shown in a locked condition; 
         FIG. 7  is a perspective view of the engagement device of  FIG. 1 , shown when an exemplary movable member is engaged therewith; and 
         FIG. 8  is a perspective view of the movable member of  FIG. 7 , shown in an opened condition. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The engagement device of the present invention allows two members, a stationary member and a movable member, to be mechanically coupled together while a user is disposed at a distance from the engagement location. The engagement device has a spring biased bar that slides in the direction of displacement of the movable member, and a seat for receiving and immobilizing an element of the movable member. 
       FIGS. 7 and 8  illustrate a vertically disposed engagement device  10 , according to one embodiment of the present invention, with which is engaged a rectilinear bracket  5  of an angled arm  62  mounted onto an exemplary movable member embodied by a pivotal service hatch  67  for selectively occluding a passageway  69  through which a building related component, including but not limited to an electrical component, an air conditioner, a roller blind box, can be accessed. An exemplary stationary member is a plaster plate  71  mounted onto a ceiling by a plurality of aluminum beams  73 . When two engagement devices  10  are mounted on the same plaster plate sidewall  74  bordering passageway  69 , hatch  69  is able to pivot more 90 degrees, and up to 150 degrees by virtue of the configuration of angled arms  62 . 
     It will be appreciated that the present invention is also applicable to an engagement device that is configured to interface with any other configured stationary and movable members. 
       FIG. 1  illustrates a front view of an unlocked engagement device  10 , when a thin, inverted U-shaped bracket  5  of a movable member is in engagement therewith. 
     Engagement device  10  has a rectilinear fixture  35  configured with an outer face  7 , i.e. facing away from the stationary member onto which it is mounted, opposed side faces  1  and  11 , an upper face  20  substantially perpendicular to outer face  7 , and a central recess  9  which is recessed with respect to outer face  7 , to accommodate the sliding vertical movement of rectangular, spring biased bar  12 . Abutting element  13  substantially perpendicular to bar  12  extends outwardly from the top thereof. A rectilinear guide element  8  with an oblique guiding surface  25  may protrude laterally, i.e. in a direction away from the central recess, from a corresponding side face, and also outwardly from outer face  7 . 
     This description refers to an engagement device when the abutting element is disposed at the top of the spring biased bar. It will be appreciated, however, that the invention is also applicable when the engagement device assumes any other suitable orientation. 
     Seating elements  16   a - b  protrude upwardly from the stepped engagement device bottom face  4  (see  FIG. 3 ), and are spaced outwardly from the bottom of side faces  1  and  11 , respectively, extending laterally therefrom for a limited distance towards recess  9 . The length of each seating element is slightly longer than the lateral dimension of foot  3 , at the bottom of each leg  6  of bracket  5 . 
     Engagement device  10  may be mounted onto the stationary member by a bolt or any other suitable fastening element insertable within apertures  27  and  28 , shown in  FIG. 2  at the rear of engagement device  10 . Apertures  27  and  28  may be formed in a corresponding recess  17  formed in outer face  7 . 
     As shown in  FIGS. 1, 2 and 6 , abutting element  13  is a thin, relatively large-surface element that is contactable by bracket  5  of the movable member and serves as an actuator for the spring. Abutting element  13 , which may be bifurcated by narrow extending elements  29  when viewed from above or from below, protrudes outwardly beyond the guide elements  8  and extends inwardly to the inner face  15  of central recess  9 , although is separated therefrom. 
     A lip  33  may slightly extend downwardly from the outer edge of abutting element  13 . A position indicating element  36 , e.g. of triangular cross section, extends downwardly from the underside of abutting element  13  between bifurcated extending elements  29  and lip  33 , to define a guiding surface  39 . 
     Protruding outwardly from bar  12  is a spring housing  14 , in which is housed spring  18  shown in  FIG. 2 . The bottom end of spring  18  is attached to base  19  of bar  12  by horizontal pin  23 , and the top end of the spring is attached to a securing element extending outwardly from rear face  21  of the engagement device. The securing element may be positioned within a cavity  2  formed at an inner region of abutting element  13 . A positioning element  23 , e.g. a pin, fitted horizontally in base  19  is adapted to contact the bottom of oval aperture  26  formed in rear face  21 , to limit the downward displacement of bar  12 . 
     Referring also to  FIG. 4 , abutting element  13  divides central recess  9  into a lower chamber  32  within which bar  12  is slidingly displaceable and an upper chamber  34  within which abutting element  13  is displaceable. Spring  18  is biased to cause bar  12  and abutting element  13  attached thereto to be displaced downwardly when a force is released from abutting element  13 . When abutting element  13  is downwardly biased, upper chamber  34  is unobstructed, making upper border element  38  of outer face  7  which borders upper chamber  34  to become accessible. 
     Although bar  12  is longitudinally slidable within central recess  9 , detachment of bar  12  from engagement device  10  is prevented by means of a plurality of teeth  24 , e.g. having a rectangular profile, which protrude inwardly into recess  9  from a corresponding sidewall  22  of the latter, to contact bar  12 , as shown in  FIGS. 1 and 3 , for example when abutting element  13  is pulled outwardly. Abutting element  13  may be notched at lateral ends thereof, to prevent interference with teeth  24 . 
     In operation, a user wishing to couple bracket  5  of the movable member to engagement device  10  directs upper edge  42  of bracket  5  to contact the portion of abutting element  13  between spring housing  14  and triangular position indicating element  36 , and applies an upward force to bracket  5 . Abutting element  13  is therefore displaced upwardly to the vicinity of upper border element  38 , providing a clearance between each bracket foot  3  and a corresponding seat  16 . Due to the presence of seating elements  16   a  and  16 , bracket  5  is held obliquely with respect to outer face  7  during upward displacement of abutting element  13 , and then each bracket foot  3  is inwardly displaced to contact outer face  7  after the clearance is produced. When the applied force is released, each bracket foot  3  is received in the interspace between a seat and a corresponding side face. Bracket  5  is consequently engaged from the top by abutting element  13 , from the bottom by bottom face  4 , inwardly by outer face  7 , outwardly by seating elements  16   a  and  16  and by position indicating element  36 , and to either lateral side by a corresponding guide element  8 . 
     If the user does not properly position the bracket upper edge  42 , guiding surfaces  25  and  39  urge bracket  5  into a correct alignment. That is, guiding surface  39  will urge bracket upper edge  42  downwardly to a correct position inwardly of position indicating element  36  if bracket upper edge  42  incorrectly contacts guiding surface  39 . Also, an inclined guiding surface  25  will urge the bracket to a correct lateral alignment if it is contacted by a bracket portion. 
     When it is desired to detach or replace the movable member, a force is simply transmitted from the bracket to the abutting element to cause the latter to be upwardly displaced, after which the bracket is removed from the engagement device. 
     To prevent inadvertent displacement of the abutting element, locking device  44  shown particularly in  FIGS. 1, 2, 4 and 5  may be used. 
     Plastically deformable locking device  44  comprises an upper element  47  and a lower element  48  which are substantially parallel to engagement device upper face  20 , a vertical wall  51  extending between upper element  47  and lower element  48 , and a handle  56  spaced outwardly from vertical wall  51  when locking device  44  is positioned to a locked condition, as shown in  FIG. 5 . Lower element  48  is significantly narrower and shorter than upper element  47 . Protruding upwardly from lower element  48  are a plurality of frictionally engageable elements  53 . The spacing between the bottom face of upper element  47  and frictionally engageable elements  53  is slightly less than the thickness of upper border element  38 . 
     Locking device  44  is pivotally displaceable about a vertical pin  43  insertable in an aperture formed in upper face  20  of thickened service element  41 , which is provided at the top of engagement device  10  and extends inwardly from outer face  7 . When locking device  44  is pivoted to a locked condition by contacting vertical wall  51 , upper element  47  covers a portion of border element  38 , lower element  48  is received in upper chamber  34  of central recess  9 , and frictionally engageable elements  53  grip the underside of border element  38  to retain engagement device  10  in the locked condition. 
     When engagement device  10  is in the locked condition, significant upward displacement of abutting element  13  is prevented as the latter will contact the bottom edge of lower element  48  and will not be able to be additionally displaced upwardly. The spring actuated by abutting element  13  is configured to be extended by a specific distance when bracket  5  is engaged by engagement device  10 , as shown in  FIG. 5 , so that abutting element  13  will abut the bottom edge of lower element  48 . Thus bracket  5  is positively engaged and cannot be removed from device  10  even if a force is applied to bracket  5  or to abutting element  13 . 
     Pulling on handle  56  will cause locking device  44  to pivot to the unlocked position, enabling abutting element  13  to be upwardly displaced and bracket  5  to be removed from engagement device  10 . 
     While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without exceeding the scope of the claims.

Summary:
A spring actuated engagement device for remotely coupling a movable member to a stationary member comprises a fixture mountable onto a stationary member, a spring biased bar that is axially displaceable within a central recess formed within the fixture, an abutting element extending outwardly from the bar for actuating the spring, and a seating element outwardly spaced from the fixture and longitudinally spaced from the abutting element. The abutting element is axially displaceable in a first direction when contacted by a first edge of a movable member, allowing a second edge of the movable member to be received in an interspace between the seating element and the outer face, and to be axially displaced in a second direction after a force that initiated the contact with the first edge is released. A pivotally displaceable locking device, when set to a locked condition, prevents displacement of the actuator.