Patent Publication Number: US-6666486-B1

Title: Slide bolt unit

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to an improved lock assembly for secure and releasible locking of a door or window or the like, particularly such as releasible locking of a semi-active door in a double door entry set. More specifically, this invention relates to an improved lock assembly having a slide bolt adapted for quick and easy fingertip actuation for displacement between an advanced locked position and a retracted unlocked position. 
     A typical double door entry set includes a primary door intended for routine opening and closing movement in the course of normal ingress and egress, in combination with a secondary or so-called semi-active door which is normally retained in a closed and locked condition. The primary door is normally equipped with door hardware including door handles or other suitable actuator devices for operating retractable door latch and deadbolt devices which commonly engage appropriate keepers mounted on the adjacent free side edge of the semi-active door. In turn, the semi-active door is normally equipped with locking hardware mounted at or near the free side edge thereof, generally proximate the upper and lower ends of the semi-active door, including retractable slide bolts for engaging appropriate keepers mounted respectively at the door header and sill. The slide bolts are normally advanced to a locked position engaging their respective keepers to retain the semi-active door normally in a closed and locked condition. However, when and if desired, these slide bolts can be retracted for disengagement from their respective keepers to unlock the semi-active door and permit opening thereof. In a common design, the slide bolts are exposed along the free side edge of the semi-active door for manual sliding displacement from the advanced locked position to the retracted unlocked position only when the primary door is open. 
     In the past, header/sill locking devices for a semi-active door of a double door entry set have generally comprised a simple slide bolt mounted in a track for sliding movement between the advanced and retracted positions, with frictional resistance between the slide bolt and track serving to retain the slide bolt in the selected advanced or retracted position. With this design, however, substantial frictional resistance sufficient to securely retain the slide bolt in the selected position of adjustment can result in a device that is difficult to operate manually. Reduced frictional resistance facilitates manual displacement of the slide bolt, but may result in reduced locking security by permitting undesired movement of the slide bolt to the retracted unlocked position in response to vibratory forces applied to the door. Such vibratory forces can be attributable to strong gusty winds, repeated shock forces from closure of the primary door, and/or an unauthorized intruder. 
     Improved security lock devices for header/sill locking of a semi-active door have been developed with a view toward overcoming these problems and disadvantages. See, for example, U.S. Pat. No. 5,290,077 which discloses and describes a header/sill lock assembly having elongated header and sill lock pins driven in unison between advanced locking positions and retracted unlocking positions in response to rotation of a thumbturn mounted near the free side edge of the semi-active door at an inner or indoor side thereof. While this header/sill locking arrangement beneficially provides significantly enhanced security locking of the semi-active door, the mechanism extends the entire height of the door and includes a significant number of parts to result in a device that is relatively complex and costly. 
     There exists a need for further improvements in and to security lock devices of the type designed for header/sill locking of a semi-active door or the like, particularly with respect to providing a relatively compact and mechanically simple device suited for quick and easy installation, and for correspondingly simple yet reliable operation while providing high security releasible locking of the door. The present invention fulfills these needs and provides further related advantages. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an improved slide bolt unit is provided for releasibly locking a door or window or the like, such as a semi-active door in a double door entry set. The slide bolt unit comprises a compact and relatively simple lock assembly constructed from a relative minimum number of parts to include an elongated slide bolt adapted for quick and easy fingertip actuation for displacement with relatively low friction between an advanced position engaging a keeper on an adjacent header or sill or the like to lock the door in a closed position, and a retracted position to permit door opening. In the advanced and retracted positions, the slide bolt unit includes means for releasibly retaining the slide bolt in place. 
     In the preferred form, the slide bolt is carried by a channel-shaped housing adapted for recessed mounting into a side edge of a door or the like. A laterally turned actuator tab on the slide bolt is exposed through a position control slot formed in the housing for fingertip access at the door side edge. The actuator tab has a slotted profile defining lock shoulders biased by a spring for normally locking with the housing by seating within one of a pair of relatively wide pockets formed respectively at the opposite ends of the position control slot, corresponding respectively with the advanced and retracted positions of the slide bolt. The actuator tab further defines a narrowed central track having a width less than the lock shoulders thereon for alignment with a narrowed central segment of the position control slot upon fingertip depression of the actuator tab against the spring to permit quick and easy sliding displacement of the actuator tab along the position control slot from one end to the other. In the preferred form, the spring is formed integrally with a first end cap mounted at one end of the channel-shaped housing. A second end cap mounted at an opposite end of the housing defines a slide port for relatively low friction sliding displacement of the slide bolt between the advanced and retracted positions. 
    
    
     Other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate the invention. In such drawings: 
     FIG. 1 is a fragmented perspective view illustrating a double door entry set including a primary door shown in an open position and a semi-active door shown in a closed position, wherein the semi-active door is locked in the closed position at the header and sill thereof by a pair of slide bolt units constructed in accordance with the present invention; 
     FIG. 2 is an enlarged fragmented perspective view corresponding with the encircled region  2  of FIG. 1; 
     FIG. 3 is an enlarged fragmented perspective view similar to FIG. 2, and shown in partially exploded form to reveal the slide bolt unit of the present invention installed into a side edge of the semi-active door generally at a lower or sill end thereof, and depicting the slide bolt unit with a slide bolt thereof in an advanced position for retaining the semi-active door locked in the closed position; 
     FIG. 4 is an enlarged fragmented perspective view similar to FIG. 3, but showing the slide bolt of the slide bolt unit in a retracted position to permit opening of the semi-active door; 
     FIG. 5 is a fragmented perspective view illustrating the slide bolt unit in exploded relation with the semi-active door; 
     FIG. 6 is an exploded front perspective view of the slide bolt unit, depicting assembly of the components thereof; 
     FIG. 7 is a rear perspective view of the assembled slide bolt unit; 
     FIG. 8 is a rear perspective view showing assembly of the slide bolt into a rearwardly open channel-shaped housing member; 
     FIG. 9 is a rear perspective view similar to FIG. 8, but depicting further assembly of the slide bolt unit including mounting of a ported end cap onto one end of the channel-shaped housing member; 
     FIG. 10 is a rear perspective view similar to FIG. 9, and showing further assembly of the slide bolt unit including mounting of a spring end cap onto an opposite end of the channel-shaped housing member; 
     FIG. 11 is an enlarged vertical sectional view taken generally on the line  11 — 11  of FIG. 5; 
     FIG. 12 is an enlarged vertical sectional view taken generally on the line  12 — 12  of FIG. 7; 
     FIG. 13 is an enlarged end view of the slide bolt taken generally on the line  13 — 13  of FIG. 6, and illustrating construction details of an actuator tab formed at one end of the slide bolt; 
     FIG. 14 is an enlarged and fragmented perspective view showing the slide bolt unit with the actuator tab releasibly locked in a first position to retain the slide bolt in the advanced position; 
     FIG. 15 is an enlarged and fragmented perspective view similar to FIG. 14, illustrating the actuator tab locked in the first position; and 
     FIG. 16 is an enlarged and fragmented perspective view similar to FIGS. 14-15, but showing depression of the actuator tab to permit sliding displacement of the slide bolt between the advanced and retracted positions. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in the exemplary drawings, an improved slide bolt unit referred to generally by the reference numeral  10  in FIGS. 1-7 is provided for releasible high security locking of a semi-active door  12  of a double door entry set  14 . As shown in FIG. 1, a pair of the slide bolt units  10  of the present invention are mounted along the free side edge  16  of the semi-active door  12  at positions respectively near the header  18  and sill  20  for releasibly locking the door  12  in a closed position. The slide bolt units  10  are suitably exposed upon movement of a related primary door  22  to an open position to permit access to and operation of the slide bolt units  10  to unlock the semi-active door  12 , when and if desired. 
     As shown in FIG. 1, the double door entry set  14  comprises a door frame mounted within a suitable opening in a building wall  24  to define an opposed pair of doorjambs  26  and  28  extending vertically between the upper header  18  and the lower sill or threshold  20 . The primary door  22  is hingedly supported by the door jamb  26  and includes appropriate door latch and/or deadbolt hardware (not shown) for engaging one or more strike sets or keepers  30  mounted centrally along the free side edge  16  of the associated semi-active door. In turn, the semi-active door  12  is hingedly supported at one side from the opposite door jamb  28  and is normally retained by the upper and lower slide bolt units  10  in a closed and locked condition. A trim strip or astragal  32  is normally mounted on the free side edge  16  of the semi-active door  12 , opposite the hinged side, and provides a convenient laterally projecting door stop surface  34  for the primary door  22  in the closed position (FIGS.  1 - 3 ). 
     The improved slide bolt unit  10  of the present invention generally comprises a compact cartridge-like assembly having a size and shape for nested or recessed mounting into a matingly shaped channel  36  formed in the free side edge  16  of the semi-active door  12 , as viewed best in FIG.  5 . In this regard, FIGS. 3-5 illustrate construction details for a single slide bolt unit  10  mounted into the side edge  16  of the semi-active door  12  generally at the lower or sill end thereof, for releasible locking engagement as will be described in more detail with a ported keeper plate  38  or the like (FIG. 4) mounted as by screws  40  onto the sill  20 . It will be recognized and understood that a similar second slide bolt unit  10  is mounted into the door side edge  16  generally at the upper or header end thereof (as viewed in FIG. 1) for releasible locking engagement with a similar keeper plate (not shown) mounted onto the header  18 . In each case, the recessed channel  36  may be formed conveniently as a simple router-cut recess, and the cartridge-shaped slide bolt unit  10  is configured to substantially fill this channel  36  in a nested and flush manner. 
     The illustrative slide bolt unit  10  generally comprises an elongated slide bolt  42  (FIGS. 6-10) having a generally strip-like configuration and constructed from a suitable hard and rugged material such as a tool steel. The slide bolt  42  has a size and shape for sliding reception into a hollow cartridge-like or channel-shaped housing  44  shown in the form of an elongated channel member having a front face  46  joined along opposite sides to a pair of rearwardly extending side legs  48  having short in-turned flanges  50  at the rear-most ends thereof. Thus, the channel-shaped housing  44  defines an open-ended and rearwardly open structure forming an elongated internal slide channel for slide-fit reception of the slide bolt  42 . One end of the slide bolt  42  is turned laterally in a forward direction to form an actuator tab  52  projecting forwardly through an open position control slot  54  formed in the front face  46  of the housing  44  near one end thereof. 
     A first end cap or spring cap  56 , which can be formed conveniently from molded plastic or like, is sized and shaped for snug press-fit reception into the open end of the channel housing  44  adjacent the position control slot  54 . More particularly, as shown best in FIGS. 6-7 and  10 - 12 , this first end cap  56  comprises a generally semicircular-shaped body  58  defining an open screw port  60 , and joined to a pair of spaced-apart guide ribs  62  sized for press-fit reception into the open end of the channel housing  44 . In addition, the first end cap  56  includes and carries a leaf spring  64  extending into the channel-shaped housing  44 , and having a width at a tip or distal end to seat firmly against the inboard surfaces of the inturned flanges  50  at the rear of the housing  44 . A central region of the leaf spring  64  is bowed forwardly to bear against a rear side of the slide bolt  42  to urge the slide bolt forwardly within the slide channel against the rear or blind side of the housing front face  46 . A pair of laterally spaced slide rails  66  extend forwardly from the opposite side edges of the leaf spring  64  to contact the slide bolt  42  in a manner providing limited or minimal running surface engagement therewith. After installation of the first end cap  56 , the rear flanges  50  on the channel housing  44  can be staked or detented as indicated by reference numeral  68  in FIG. 7, to lock the end cap in place. In the preferred form, the spring cap  56  inclusive of the leaf spring  64  is formed as an integrally molded unit. 
     A second end cap or slide cap  70 , which may also be formed from a suitable molded plastic or the like, is provided for snug press-fit reception into the opposite end of the channel housing  42 . This second end cap  70  generally comprises a rectangular plug defining a rectangular slide port  72  for relatively low friction sliding reception of the end of the slide bolt  42  opposite the actuator tab  52 . A leading or inboard end of the slide cap  70  may be beveled for quick and easy press-fit reception into the channel housing  42 , and a cap flange or plate  73  (FIG. 6) is formed at the trailing end thereof for closely overlying the housing end to provide a finished look. After installation of the second end cap  70 , the rear flanges  50  of the channel housing  44  can be staked or detented as indicated by reference numeral  74  in FIG. 7, to lock the end cap in place. 
     The thus-assembled slide bolt unit  10 , comprising the slide bolt  42  with actuator tab  52  thereon, the channel housing  44 , and the two end caps  56  and  70 , constitutes a compact cartridge-like assembly for nested and flush mounting into the matingly shaped channel  36  formed in the door side edge  16  (shown best in FIG.  5 ). A single screw  76  can be fastened through the screw port  60  in the first end cap  56  to lock the slide bolt unit  10  in place, with the actuator tab  52  projecting laterally outwardly with respect to the door side edge  16 . The associated trim strip or astragal  32  can then be mounted onto the door side edge  16  in a position to substantially overlie the slide bolt unit  10 , with the actuator tab  52  recessed but otherwise exposed for fingertip access within an elongated access port  77  formed in the trim strip  32  (FIGS.  2 - 3 ). In this regard, the trim strip  32  is normally mounted onto the door side edge  16  by one or more mounting screws  78 , wherein one of the screws  78  can be fastened into the door side edge through a screw port  79  in the trim strip and further through an open screw port  80  formed in the front face  46  of the channel housing  44  (FIGS.  2 - 3 ). Importantly, this mounting screw  78  extends through an elongated vertical slot  82  formed in the slide bolt  42  (FIGS. 6-12) so that secure mounting of the slide bolt unit  10  and overlying trim strip  32  does not obstruct sliding movement of the slide bolt  42  between the advanced and retracted positions. 
     Displacement of the slide bolt  42  between the advanced and retracted positions is regulated by the actuator tab  52  which has a slotted or contoured profile chosen for controlled interfit with the position control slot  54 . More particularly, as shown best in FIGS. 3-6,  8 - 10  and  14 - 16 , the position control slot  54  has a narrow width central segment  84  defined by generally parallel slot edges extending between relatively short but comparatively wider opposite end segments or notches  86 . The slotted profile of the actuator tab  52  (shown best in FIG. 13) defines a narrow width central track  88  sized to permit sliding movement along the narrow central segment  84  of the position control slot  54 , when the actuator tab  52  is pressed inwardly relative to the channel housing  44  to align the tab track  88  with the longitudinal edge margins of the slot central segment  84 . The slotted profile of the actuator tab  52  additionally defines a pair of comparatively wider lock shoulders  90  underlying the central track  88 , wherein these lock shoulders  90  cooperatively define an actuator tab width greater that the slot central segment  84  but sufficiently narrow for reception into either one of the wider slot end notches  86 . 
     Importantly, the leaf spring  64  on the spring cap  56  bears against the rear side of the slide bolt  42  at a location longitudinally between the actuator tab  52  and the slide cap  70  for urging or biasing the actuator tab  52  in a forward direction within the housing  44  relative to the position control slot  54 . Accordingly, when the slide bolt  42  is in a position wherein the actuator tab  52  is aligned with either one of the wider slot end notches  86  of the position control slot  54 , corresponding respectively with the advanced or retracted positions of the slide bolt  42 , the leaf spring  64  urges the lock shoulders  90  into the aligned slot end notch  86  to lock the actuator tab  52  and the associated slide bolt  42  in place. FIGS. 14-15 show the actuator tab  52  with its lock shoulders  90  engaging the slot end notch  86  associated with the slide bolt  42  in an advanced position protruding from the slide end cap  70  to engage and lock with the associated keeper plate  38 . As shown, the lock shoulders  90  protrude into the plane of the position control slot  54 , and define a transverse width sufficient to block displacement or translation of the actuator tab  52  along the narrower central segment  84  of the position control slot  54 . 
     When it is desired to shift the lock bolt  42  from the advanced locking position to the retracted position, or vise versa, the actuator tab  52  can be depressed quickly and easily with fingertip pressure to push the lock shoulders  90  thereon out of alignment with the associated widened end notch  86  of the position control slot  54 , and to orient the narrower tab track  88  into coplanar alignment with the slot  54 . In this position, as viewed in FIG. 16, the actuator tab  52  can be shifted manually with relatively minimal fingertip pressure to displace the slide bolt  42  from the advanced position to the retracted position, or vice versa. During such displacement, the lock shoulders  90  are urged by the spring  64  into sliding and running engagement with the blind side of the housing front panel  46  along the side margins of the position control slot  54  to provide relatively a small surface contact area with correspondingly minimal running friction therebetween. In addition, the slide rails  66  on the leaf spring  64  contact the rear side of the slide bolt  42  for substantially minimized running friction therebetween. When the actuator tab  52  is displaced to the opposite end of the position control slot  54 , into alignment with the widened end notch  86  at said opposite end, the leaf spring  64  again urges the actuator tab  52  forwardly relative to the slot  54  for re-engaging the tab lock shoulders  90  with the widened slot notch  86 . This results in re-locking the position of the slide bolt  42  in the selected retracted or advanced position until the actuator tab  52  is subsequently depressed and shifted along the position control slot  54  back to the opposite end thereof. 
     The improved slide bolt unit  10  of the present invention thus provides a relatively simple device adapted for quick and easy assembly from a minimum number of components, and for quick and easy fingertip operation to displace the slide bolt  42  between the advanced locked position and the retracted unlocked position. The slide bolt  42  is configured to extend generally in a plane that is transverse to a direction of initial opening movement of the door, whereby the slide bolt  42  has the capacity to retain the door in a securely locked condition in the presence of relatively strong forces such as hurricane force winds acting on the door. The releasibly locked engagement of the slide bolt  42  in the advanced position additionally enhances locking security by minimizing risk of inadvertent slide bolt retraction in response to vibratory or other forces applied to the door. However, the slide bolt can be displaced quickly and easily between the advanced and retracted position with a simple fingertip actuation, and with relatively minimal running friction between the moving parts. The improved slide bolt unit  10  can be mounted reversibly at a door header or sill, or in a right-hand or left-hand orientation, without requiring component modification. 
     A variety of further modifications and improvements in and to the slide bolt assembly of the present invention will be apparent to those persons skilled in the art. For example, while the invention is shown and described in the form of separately actuated header and sill lock units for a semi-active door in a double door entry set, it will be recognized that this pair of lock units may be actuated in unison by a common actuator of the type described in U.S. Pat. No. 5,290,077. Moreover, is will be appreciated that the slide bolt unit of the present invention may be utilized singly or in multiples in other panel-type door and window applications, and in a variety of vertically and horizontally extending orientations, for releasibly locking a hinged panel or the like in a normally closed position. Accordingly, no limitation on the invention is intended by way of the foregoing description and accompanying drawings, except as set forth in the appended claims.