Patent Publication Number: US-11047156-B2

Title: Compression latch having a reduced protrusion

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Phase Application of PCT International Application PCT/US2016/041873, filed Jul. 12, 2016, which claims priority to U.S. Provisional Patent Application No. 62/192,264, entitled COMPRESSION LATCH HAVING A REDUCED PROTRUSION, filed on 14 Jul. 2015, the contents of each of which are incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to latches, and particularly, to compression latches that can be used for securing storage compartments and can provide for reduced protrusion of the latches into such compartments. 
     BACKGROUND OF THE INVENTION 
     Conventionally, storage compartments in restricted areas (such as medical environments for example) must be secured to prevent unauthorized access to their contents. Latches may be used to restrict access to such compartments to users having a corresponding key. 
     Depending on the environment or intended use, many storage compartments may have a united amount of available space, or may store objects that take up substantially all of the space within the compartment. For these types of compartments, it may be advantageous that the latch used for securing the compartment not unnecessarily protrude or impinge upon the limited space available. Accordingly, improved systems and devices are desired for securing storage compartments without negatively impacting available storage space yet while maintaining good latch performance. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention are related to latches. 
     According to one aspect of the invention, a latch is configured to fix a panel elative to a frame. The latch includes a housing configured for engagement to the panel, the housing having a longitudinal axis and defining an aperture along the longitudinal axis. The latch also includes a cap mounted within the aperture of the SEE housing for rotation about the longitudinal axis, the cap defining a longitudinally extending recess. Also included in the latch is a shaft extending along the longitudinal axis within the aperture of the housing, the shaft being mounted for rotation about the longitudinal axis, the shaft further being mounted for axial movement relative to the cap, the shaft having a guide portion movably received in the recess of the cap. A spring of the latch is configured to bias the shaft away from the cap along the longitudinal axis, and a sleeve of the latch is interposed between the shaft and the housing, the sleeve defining a first slot. The latch also includes a cam interposed between the shaft and the housing, the cam being rotatable relative to the sleeve about the longitudinal axis, the cam defining a second slot. A pin is provided extending radially outwardly from the shaft relative to the longitudinal axis, the pin extending into fs the first and second slots. The latch also includes a pawl coupled to the shaft, the pawl being configured to engage the frame. The first and second slots are configured to guide the rotation and axial movement of the shaft as the cap is rotated within the housing such that the pawl engages or disengages the frame. 
     The cap can include a drive stud extending along the longitudinal axis and forming a drive surface for rotating the cap. If so, the recess of the cap can be at least partially defined within the drive stud. 
     The cap can also define a drive opening extending along the longitudinal axis and forming a drive surface for rotating the cap. If so, the recess of the cap can overlap with the drive opening in a radial direction of the cap, and the recess of the cap can extend to a position radially outward from the drive opening. 
     The spring can be positioned to surround the guide portion of the shaft, and the spring can extend between opposed surfaces of the shaft and the cap and have ends abutting the opposed surfaces. The opposed surface of the cap can be formed within the recess of the cap. The spring can include one or more of the following elements: compression springs, wave springs, belleville washers, elastomeric springs, and/or conical springs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is best understood from the following detailed description when read in connection with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. Included in the drawings are the following figures: 
         FIG. 1  depicts an exemplary latch configured to fix a panel relative to a frame in accordance with aspects of the present invention; 
         FIG. 2  depicts an exploded view of the latch of  FIG. 1 ; 
         FIG. 2A  depicts an enlarged exploded view of components of the latch of  FIG. 1 ; 
         FIGS. 3A-3E  depict an exemplary housing of the latch of  FIG. 1 ; 
         FIGS. 4A-4E  depict an exemplary cap of the latch of  FIG. 1 ; 
         FIGS. 5A-5E  depict an exemplary shaft of the latch of  FIG. 1 ; 
         FIGS. 6A-6C  depict a first step of an exemplary opening operation of the latch of  FIG. 1  with a panel and frame; 
         FIGS. 7A-7C  depict a second step of the opening operation of  FIGS. 6A-6C ; 
         FIGS. 8A-8C  depict a third step of the opening operation of  FIGS. 6A-6C ; 
         FIGS. 9A-9C  depict an alternate exemplary cap of a latch in accordance with aspects of the present invention; 
         FIGS. 10A-10C  depict an alternate exemplary shaft of a latch in accordance with aspects of the present invention; 
         FIGS. 11A and 11B  depict an alternate first step of an exemplary opening operation of a latch in accordance with aspects of the present invention; 
         FIGS. 12A and 12B  depict an alternate second step of the opening operation of  FIGS. 11A and 11B ; 
         FIGS. 13A-13E  depict another alternate exemplary cap of etch in accordance with aspects of the present invention; 
         FIGS. 14A-14E  depict another alternate exemplary shaft of a latch in ns accordance with aspects of the present invention; 
         FIGS. 15A and 15B  depict another alternate first step of an exemplary opening operation of a latch in accordance with aspects of the present invention; and 
         FIGS. 16A and 16B  depict an alternate second step of the opening operation of  FIGS. 15A and 15B . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. 
     The exemplary latches described herein have a lower profile than conventional latches for storage compartments in that they can provide for a reduction of the degree of the protrusion of the latch into such compartments, decreasing or eliminating the effect of the latch on available storage space. These embodiments generally incorporate a latch cap and shaft which rotatably and axially move to open or close the compartment. 
     While particular latch embodiments are described herein, components the disclosed embodiments may be incorporated into any conventional latches known to one of ordinary skill in the art to achieve the advantages described herein. For example, components of the disclosed embodiments may be it into those latches described in U.S. Pat. No. 4,583,775, the contents of which are incorporated herein by reference in their entirety. Likewise, the disclosed latches may be usable on any structure, including any type of storage compartments in which it is desirable to secure the contents of the compartment. The latch is preferably a compression latch for use with a panel mounted to a frame. Such a compression latch is configured for movement from an open position in which a panel is not latched relative to the frame, to a latched position in which the panel is latched relative to the frame, and to a locked position in which the panel is pulled against the frame such that they are compressed against one another. 
     Referring now to the drawings,  FIGS. 1-8C  illustrate an exemplary latch  100  in accordance with aspects of the present invention. Latch  100  is configured to fix a panel  10  relative to a frame  20 , as shown in  FIGS. 6A, 7A, and 8A . As a general overview, latch  100  includes a housing  110 , a cap  120 , a shaft  130 , a spring  140 , a sleeve  150 , a cam  160 , pin  170 , and a pawl  180 . Additional details of latch  100  are described below. 
     Housing  110  houses the components of latch  100 . Housing  110  is configured for engagement to panel  10 . In an exemplary embodiment, housing  110  has a body portion  112  sized to fit within a through-hole in panel  10 . Housing  110  further includes a flanged portion  114  extending circumferentially around an outer surface of body portion  112 . Flanged portion  114  is sized to contact an inner or outer surface of panel  10  when body portion  112  of housing  110  is received within the through-hole. 
     In a preferred embodiment, housing  110  engages with panel  10  using a nut  102 . Nut  102  is adapted to be screwed onto threading  115  formed on the outer surface of body portion  112 , such that panel  10  is clamped between flanged portion  114  and nut  102 . A washer  104  may be added between panel  10  and nut  102  to create an appropriate securement of latch  100  to panel  10 . Additionally, a gasket (not shown) may be added between panel  10  and the flanged portion  114  of the housing  110  to secure the interior of the compartment from external elements such as liquid or dust. The use of nut  102  within the compartment to secure latch  100  to panel  10  desirably prevents unauthorized removal of latch  100  from panel  10 . 
     Alternatively or additionally, housing  110  may engage with panel  10  by any other means, including for example a frictional or threaded fit of body portion  112  within the through-hole of panel  10  or adhering the flanged portion  114  to the surface of panel  10 . For example, a fastener such as a screw can be used as can bracket mounting configurations. Still further, a portion or all of housing  110  may be formed an integral or unitary piece with panel  10 . 
     Body portion  112  of housing  110  extends along a longitudinal axis. As shown in  FIGS. 6C, 7C, and 8C , the longitudinal axis generally extends in a direction orthogonal to the plane of panel  10 . Nonetheless, it will be understood from the description herein that the longitudinal axis may extend at an oblique angle relative to panel  10 , and the direction of the longitudinal axis is not intended to be limited. 
     Body portion  112  of housing  110  further defines an aperture  116  therein which extends along the longitudinal axis. Aperture  116  is sized to accommodate the components of latch  100 , as described below. 
     Housing  110  may further include at least indicator  118 , as shown in  FIGS. 3A-3E . Indicator  118  may be provided to indicate to a user the rotational location of the start or end point of the keyed components of the latch. In an exemplary embodiment, indicator  118  is a notch which, when aligned with a corresponding indicator  125  of cap  120 , indicates to the user that cap  120  is in the unrotated (secured or locked) position. The latch is moveable from an open position in which a panel is not latched relative to the frame, to a latched position in which the panel is latched relative to the frame, and to a locked position in which the panel is pulled against the frame such that they are compressed against one another. 
     Cap  120  is mounted at least partially within aperture  116  of housing  110 . Cap  120  is not affixed to housing  110 , so that it can rotate relative to housing  110  around the longitudinal axis. As shown in  FIGS. 4A-4E , cap  120  may have a circular shape in order to enable unobstructed rotation of cap  120  within housing  110 . 
     Cap  120  may be prevented from axial movement relative to housing  110 . In an exemplary embodiment, cap  120  includes a retainer  121 . Retainer  121  may be formed as a split ring which surrounds an outer surface of cap  120 . Retainer  121  is accommodated within a groove  123  formed along the outer circumferential surface of cap  120  and a corresponding groove  113  formed along the inner circumferential surface of housing  110 . When retainer  121  is seated within grooves  113  and  123 , it prevents axial movement of cap  120  out of the aperture  116  defined by body portion  112 . 
     In a preferred embodiment, a gasket such as an o-ring  106  may be added between housing  110  and cap  120  in order to secure the interior of body portion from external elements such as liquid or dust. Cap  120  and/or housing  110  may include all annular groove or surface for accommodating gasket  106  between cap  120  and housing  110 . 
     Cap  120  includes at least one drive surface  122  on its upper surface, as shown in  FIGS. 4A-4E . Drive surface  122  is accessible when cap  120  is mounted within housing  110 , in order to enable a user to drive or rotate cap  120 , e.g., with a key. Drive surface  122  may be formed with a shape corresponding to a shape of a key (not shown). In this form, cap  120  cannot readily be rotated relative to housing  110  without the corresponding key for engaging with drive surface  122 . 
     Cap  120  further includes at least one longitudinally extending recess  124 . Recess  124  is formed in a lower surface of cap  120 , opposite drive surface  122 . Recess  124  is formed to mate with a portion of shaft  130 , as described below. 
     In one embodiment, cap  120  comprises a drive stud  126  extending from an upper surface of cap  120  along the longitudinal axis. Drive stud  126  may form the drive surface  122  for rotating cap  120 . In this embodiment, recess  124  overlaps with drive stud  126  in the radial direction of housing  110 . In other words, recess  124  is at least partially defined within drive stud  126 . 
     Alternatively or additionally, cap  120  comprises a drive opening  128  extending into an upper surface of cap  120  along the longitudinal axis. Drive opening  128  may also form the drive surface  122  for rotating cap  120 . In this embodiment, recess  124  overlaps with drive opening  128  in the radial direction of housing  110 . In other words, recess  124  extends longitudinally to a position that is either radially outward from or radially inward from drive opening  128 . 
     Overlap between recess  124  and the drive surface  122  of cap  120  is advantageous to lower the protrusion of latch  100 . As set forth below, recess  124  is provided in order to define the direction of axial movement of shaft  130  during opening of latch  100 . By creating a radial overlap between recess  124  and drive surface  122  (defined by drive stud  126  and/or drive opening  128 ), the overall height H of cap  120  (shown in  FIG. 4C ) and/or the length of the shaft  130  may be decreased, and the overall protrusion P of latch  100  (shown in  FIG. 6C ) may be lowered. Preferably, latch  100  has an overall protrusion P of no more than approximately 30 mm measured from the outer surface of the panel (corresponding to the bottom edge of the flanged portion  114  extending circumferentially around an outer surface of body portion  112  of the housing  110 ) to the base of the screw  182 . A conventional latch may have a protrusion P of about 40 mm. This protrusion P can, for example, be reduced to about 30 mm according to an exemplary embodiment of this invention. 
     The embodiments illustrated in the figures are of a fixed grip style in which the position of the mounting of the pawl on the body of the latch is fixed in longitudinal position by the screw  182  and the housing  110 . In other words, the position of the pawl cannot be easily adjusted by the user in this embodiment. In another embodiment having an adjustable grip feature, the position of the mounting of the pawl on the body of the latch can be adjusted using, for example, nuts to capture the position of the pawl at a user-selected position. A conventional latch having an adjustable grip feature may have a longer protrusion P of about 64 mm for example. This protrusion P can, for example, be reduced to about 54 mm according to an exemplary embodiment of this invention. In other words, protrusion P can be reduced by up to about 10 mm or even more for various latch configurations as compared to conventional latch designs. 
     As shown in  FIGS. 6A, 7A, and 8A , a panel  20  and a gasket (not shown) are positioned between the panel  20  and the bottom edge of the flanged portion  114  extending circumferentially around an outer surface of body portion  112  of the housing  110 . The panel  20  and gasket are not shown in  FIGS. 6C, 7C, and 8C ; instead, a gap represents the space that would otherwise be occupied by the panel  20  and the gasket. 
     Cap  120  may further includes at least one indicator  125 . Indicator  125  may be provided to indicate to a user the rotational location of cap  120  relative to housing  110 . In an exemplary embodiment, indicator  125  is a notch which is positioned to align with a corresponding indicator  118  on housing  110  to indicate to the user when cap  120  is in the unrotated (secured) position. 
     Shaft  130  is mounted at least partially within aperture  116  of housing  110 . Shaft  130  extends along the longitudinal axis of housing  110 . Shaft  130  is mounted to be rotatable around the longitudinal axis relative to housing  110  and cap  120 . As shown in  FIGS. 5A-5E , shaft  130  may have a circular shape in order to enable unobstructed rotation of shaft  130  within housing  110 . 
     Shaft  130  is mounted to be axially movable relative to housing  110  and cap  120 . In an exemplary embodiment, shaft  130  includes a guide portion  132 . Guide portion  132  extends upward from shaft  130  in the axial direction toward cap  120 . Guide portion  132  is sized to be received within recess  124  of cap  120 . The sliding engagement of guide portion  132  within recess  124  defines the direction of the axial movement of shaft  130  relative to cap  120 . 
     Shaft  130  further includes a through-hole  134 . Through-hole extends in the radial direction through the body of shaft  130 . Through-hole  134  is shaped to accommodate a pin  170  passing through shaft  130 , as described in further detail below. 
     Shaft  130  further includes a threaded recess  136  in a lower end thereof. Threaded recess  136  is sized to accommodate a screw  182  for affixing pawl  180 , as described in further detail below. 
     Spring  140  is configured to bias shaft  130  away from cap  120  along the longitudinal axis. In an exemplary embodiment, spring  140  is a compression spring positioned to surround guide portion  132  of shaft  130 . The spring can include one or multiple elements, such as compression springs, wave springs, belleville washers, elastomeric springs, and/or conical springs. Spring  140  extends from a surface  127  on cap  120  to an opposing surface  138  on shaft  130 , and has ends abutting the respective surfaces  127  and  138 . In an exemplary embodiment, surface  127  of cap  120  is defined within recess  124 , in order to reduce or further reduce the overall height H of cap  120 . 
     Sleeve  150  is positioned within aperture  116  interposed between housing  110  and shaft  130 . Sleeve  150  thus defines an aperture in which shaft  130  is positioned. 
     Sleeve  150  is mounted within housing  110  in such a manner to prevent rotation of sleeve  150  relative to housing  110 . In an exemplary embodiment, sleeve  150  includes one or more keying features  152  positioned to mate with keying features  119  in housing  110 . Keying features  152  and  119  may be detents, projections, recesses, or any other anti-rotation structures known to one of ordinary skill in the art from the description herein. Alternatively, all or a portion of sleeve  150  may be formed integrally or as a unitary piece with housing  110 . 
     Sleeve  150  defines a pair of slots  154 . Slots  154  are sized to receive pin  170  therein, and to allow axial and/or circumferential movement of pin  170  along each slot  154 . In an exemplary embodiment, and referring to  FIG. 2A  which shows an enlarged exploded view of the sleeve  150  and cam  160 , each slot  154  has an L-shape, with a first portion  154 A extending in the longitudinal or axial direction of housing  110 , and a second portion  154 B extending, in the circumferential direction of housing  110 . The first and second portions  154 A,  154 B of each slot  154  guide the movement of shaft  130  within housing  110  during an opening or closing operation of latch  100 , as described in greater detail below. 
     Cam  160  is positioned within the aperture of sleeve  150  interposed between sleeve  150  and shaft  130 . Cam  160  is mounted within sleeve  150  to be rotatable relative sleeve  150  around the longitudinal axis. In particular, cam  160  is mounted to be rotatable with cap  120 . In an exemplary embodiment, cam  160  includes one or more keying features  162  positioned to mate with keying features  129  in the lower surface of cap  120 . Keying features  162  and  129  may be detents, projections, recesses, or any other anti-rotation structures known to one of ordinary skill in the art from the description herein. 
     Cam  160  defines a pair of slots  164 . Slots  164  are sized to receive pill  170  therein, and to allow axial and/or circumferential movement of pin  170  along each slot  164 . In an exemplary embodiment, each slot  164  is spirally curved around the outer circumferential surface of cam  160  between a first Position near cap  120  and a second position axially spaced from the first position away from cap  120 . With slots  154 , slots  164  guide the movement of shaft  130  within housing  110  during an opening or closing operation of latch  100 , as described in greater detail below. 
     While cam  160  is described as being positioned within sleeve  150 , it will be understood that the invention is not so limited. Cam  160  could alternatively be positioned outside of sleeve  150 , such that sleeve  150  is interposed between cases  160  and shaft  130 , without departing from the scope of the invention. 
     Additionally, while cam  160  is described as being a separate component from cap  120 , it will be understood that the invention is not so limited. Alternatively, all or a portion of cam  160  could be formed integrally or as a unitary piece with cap  120 . Such a structure may be desired in order to further minimize the overall protrusion P of latch  100 . 
     Pin  170  extends radially outward from shaft  130  relative to the longitudinal or axial direction of housing  110 . Pin  170  is captured within an aperture formed in the shaft  130 , and is received with slots  154  and  164 . As a result, shaft  130  is limited to moving rotationally or axially within the path defined by the engagement of pin  170  with slots  154  and  164 . 
     In an exemplary embodiment, pin  170  is a cylindrical post extending diametrically through through-hole  134  of shaft  130 . The post has a length sufficient to form diametrically opposed pins  170  on either side of shaft  130 . In this embodiment, sleeve  150  and cam  160  may each include a pair of diametrically opposed slots  154  and  164  on, either side thereof. Accordingly, while the operation, of latch  100  is described herein with respect to a single slot  154 ,  164  and pin  170 , it will be understood by one of ordinary skill in the art that one, two, or more respective slots and pins may be used without departing from the scope of the invention. 
     Pawl  180  is coupled to shaft  130 . In an exemplary embodiment, pawl  180  is fixedly coupled to the lower end of shaft  130  via a screw  182  that is engaged with threaded recess  136 . A washer  184  may be added between screw  182  and pawl  180  to create an appropriate securement of pawl  180  to shaft  130 . Pawl  180  is movable between a closed position and an open position. 
     Pawl  180  is moved between the closed position and the open positioned by rotation and axial movement of shaft  130 . In the closed position, shown in  FIG. 6A , pawl  180  engages frame  20  and fixes panel  10  relative to frame  20 . In the open position, shown in  FIG. 8A , pawl  180  disengages from frame  20 , and allows relative movement of panel  10  relative to frame  20 . 
     An exemplary operation of latch  100  is described below with respect to  FIGS. 6A-8C . As will be evident from the description below, the slots  154  and  164  are configured to guide the rotation and axial movement of shaft  130  as cap  120  is rotated within housing  110 , such that pawl  180  engages with or disengages from frame  20 . 
       FIGS. 6A-6C  show latch  100  in the closed position. As shown in  FIG. 6A , pawl  180  is rotated to engage with frame  20  in the closed position. As shown in  FIG. 6B , indicators  118  and  125  are aligned, indicating to the user that cap  120  is in the unrotated (secured) position. As shown in  FIG. 6C , shaft  130  is at an axially uppermost position, with guide portion  132  fully received within recess  124  of cap  120 , and spring  140  fully compressed. 
     At this stage, in order to open latch  100 , a user engages a key with drive surface  122  of cap  120  and begins rotating. Rotating cap  120  causes a corresponding rotation of cam  160 , e.g., due to keying features  162  and  129 . As cam  160  rotates, the spiral slot  164  of cam  160  applies a force to pin  170  in an axial and circumferential direction. The first portion of the L-shaped slot  154  allows movement of pin  170  in the axial direction, and prevents movement of pin  170  in the circumferential direction. As a result, rotation of cap  120  and cam  160  from the closed position causes pin  170 , and correspondingly shaft  130 , to move only in the axial direction away from cap  120  (under bias from spring  140 ). This axial movement of shaft  130  moves pawl  180  axially downward and away from frame  20 . The axial movement of pin  170  proceeds until pin  170  reaches the second portion of L-shaped slot  154 . 
       FIGS. 7A-7C  show latch  100  in a position between the opened and closed positions, after pin  170  reaches the second portion of L-shaped slot  154 . As cam  160  continues to rotate, the spiral slot  164  of cam  160  continues to apply a force to pin  170  in an axial and circumferential direction. The second portion of the L-shaped slot  154  prevents further movement of pin  170  in the axial direction, but allows movement of pin  170  in the circumferential direction. As a result, continued rotation of cap  120  and cam  160  causes pin  170 , and correspondingly shaft  130 , to move only in the rotational or circumferential direction. This rotational movement of shaft  130  moves pawl  180  rotationally away from frame  20 . As shown in  FIGS. 7A and 7B , pawl  180  has begun to rotate away from frame  20  toward the open position. As shown in  FIG. 7B , indicators  118  and  125  are no longer aligned, as cap  120  has been rotated counterclockwise from the closed position. As shown in  FIG. 7C , shaft  130  is at an axially lowermost position, with spring  140  fully extended. Shaft  130  has begun to rotate, and the cross-section of pin  170  shown in  FIG. 7C  is slightly elliptical in shape. 
     While the exemplary embodiment in  FIGS. 7A-7C  (and elsewhere herein) depict a counterclockwise rotation of the cap, it will be understood that the operations described herein may alternatively be performed with a clockwise rotation of the cap. 
       FIGS. 8A-8C  show latch  100  in an open position, after pin  170  reaches the end of the second portion of L-shaped slot  154 . Rotation of cap  120  and cam  160  may be continued until pin  170  reaches the end of slot  154 , and no more rotational movement of pin  170  of shaft  130  is possible. As shown in  FIGS. 8A and 8B  pawl  180  has been fully rotated, and cannot engage frame  20 . As shown in  FIG. 8B , full rotation of cap  120  constitutes approximately 180° from the closed position, as shown by the different between indicators  118  and  125 . It will be understood, however, that the rotational distance between the fully open and closed position may be any desired distance. As shown in FIC.  8 C, shaft  130  has been fully rotated, and the cross-section of pin  170  shown in  FIG. 8C  is elliptical in shape (as it passes through the sidewalk of the cylindrical pin. 
     An alternative cap  220  is illustrated in  FIGS. 9A-9C . Cap  220  may include all of the structures or features set forth above with respect to cap  120 , except as set forth below. 
     Cap  220  further includes at least one longitudinally extending recess  124  formed in a lower surface of cap  220 . Recess  124  includes a surface  127  therein which supports spring  140 . Surface  127  of cap  120  is defined within recess  124 , in order to reduce or further reduce the overall height H of cap  120 . 
     Surface  127  includes an annular protrusion  227  in an inner edge thereof, as shown in  FIG. 9B . Protrusion  227  extends toward the opening of recess  124 . Protrusion  227  may promote proper seating of spring  140  against surface  127 . Additionally, protrusion  227  may prevent guide portion  132  from deviating side-to-side in recess  124 , and/or prevent guide portion  132  from contacting and/or interfering with spring  140 . 
     Cap  220  further includes keying features  229  in the lower surface of cap  220 , as shown in  FIG. 9C . Keying features  229  mate with keying features  162  on cam  160 . Unlike keying features  129 , keying features  229  do not extend all the way to the periphery of cap  220 . Keying features  229  may terminate before the periphery of cap  220 , since cam  160  is narrower than cap  220 , and mating keying features  162  are located radially inward from the periphery of cap  220 . 
     An alternative shaft  230  is illustrated in  FIGS. 10A-10C . Shaft  230  may include all of the structures or features set forth above with respect to shaft  130 , except as set forth below. 
     Shaft  230  includes a guide portion  132  extending upward from shaft  130 , as shown in  FIG. 10B . Guide portion  132  extends in the axial direction toward cap  220 . Guide portion  132  is sized to be received within recess  124  of cap  220 . The sliding engagement of guide portion  132  within recess  124  and inside protrusion  227  defines the direction of the axial movement of shaft  230  relative to cap  220 . 
     Shaft  230  includes a surface  138  which supports spring  140  when spring  140  surrounds guide portion  132 . Guide portion  132  may further include a flared section  238  adjacent surface  138 , as shown in  FIG. 10C . Flared section  238  may promote proper seating of spring  140  against surface  138 . Additionally, flared section  238  may prevent spring  140  from deviating side-to-side adjacent guide portion  132 . 
     Steps of an alternate opening operation is illustrated in  FIGS. 11A-12B .  FIGS. 11A and 11B  show a latch in the closed position. As shown in  FIG. 11A , indicators  118  and  125  are aligned, indicating to the user that cap  220  is in the unrotated (secured) position. As shown in  FIG. 11B , shaft  230  is at an axially uppermost position, with guide portion  132  fully received within recess  124  of cap  220  inside protrusion  227 , and spring  140  fully compressed. 
       FIGS. 12A and 12B  show a latch in a position between the opened and closed positions. Continued rotation of cap  220  causes pin  170 , and correspondingly shaft  230 , to move only in the rotational or circumferential direction. This rotational movement of shaft  230  moves pawl  180 . As shown in  FIG. 12A , indicators  118  and  125  are no longer aligned, as cap  220  has been rotated counterclockwise from the closed position. As shown in  FIG. 12B , shaft  230  is at an axially lowermost position, with spring  140  fully extended. Protrusion  227  projects below the tip of guide portion  132 , and thereby prevents guide portion  132  from deviating side-to-side in recess  124 . Likewise, flared section  238  prevents spring  140  from deviating side-to-side adjacent guide portion  132 . 
     Another alternative cap  320  is illustrated in  FIGS. 13A-13E . Cap  320  may include all of the structures or features set forth above with respect to cap  120  and/or cap  220 , except as set forth below. 
     Cap  320  includes at least one drive surface  322  on its upper surface, as shown in  FIGS. 13A-13E . Drive surface  322  is provided in order to enable a user to drive or rotate cap  320  e.g., with a hexagonal key. In this embodiment, cap  320  comprises a drive opening  328  extending into an upper surface of cap  320  along the longitudinal axis. Drive opening  328  forms the drive surface  322  for rotating cap  320 . 
     Cap  320  further includes at least one longitudinally extending recess  124  formed in a lower surface of cap  320 . In this embodiment, there is no overlap between recess  124  and drive opening  328  in the radial direction of the housing. In other words, recess  124  extends longitudinally to a position that is either radially outward from or radially inward from drive opening  328 . 
     Another alternative shaft  330  is illustrated in  FIGS. 14A-14E . Shaft  330  may include all of the structures or features set forth above with respect to shaft  130  and/or shaft  230 , except as set forth below. 
     Shaft  330  includes no guide portion extending upward from shaft  130 , as shown in  FIGS. 14A, 14C, and 14E . In its place, shaft  230  includes a disc-shaped surface  338  which supports spring  140  when spring  140  is in place. 
     Steps of another alternate opening operation is illustrated in  FIGS. 15-16 .  FIGS. 15 and 15  show a latch in the closed position. As shown in  FIG. 15 , indicators  118  and  125  are aligned, indicating to the user that cap  320  is in the unrotated (secured) position. As shown in  FIG. 15B , shaft  330  is at an axially uppermost position, with spring  140  fully compressed between the upper surface of recess  124  and surface  338  of shaft  330 . 
       FIGS. 16A and 16B  show a latch in a position between the opened and closed positions. Cap  320  is rotated, e.g., by insertion of a hexagonal key into drive opening  328 . Rotation of cap  320  causes pin  170 , and correspondingly shaft  330 , to move only in the rotational or circumferential direction. This rotational movement of shaft  330  moves pawl  180 . As shown in  FIG. 16A , indicators  118  and  125  are no longer aligned, as cap  320  has been rotated counterclockwise from the closed position. As shown in  FIG. 16B , shaft  330  is at an axially lowermost position, with spring  140  fully extended between the upper surface of recess  124  and surface  338  of shaft  330 . 
     As noted previously, the exemplary latches described herein can have a lower protrusion as compared to conventional latches for enclosed spaces so as to reduce the area taken by the latches within those spaces. For example, when exemplary compression latches are used in connection with storage compartments, they can provide for a reduction of the degree of the protrusion of the latch into such compartments, thus decreasing or eliminating the effect of the latch on available storage space. 
     According to preferred aspects of this invention, this reduction of the degree of the protrusion of the latch is accomplished without compromising other performance benefits. For example, the invention makes it possible to reduce the degree of the protrusion of the latch as compared to conventional compression latches while at the same time maintaining at least one of or all of (1) the same pull-up or stroke of the latch&#39;s pawls as compared to conventional compression latches, (2) the same feel and smooth operation as compared to conventional compression latches, and (3) the same compressive force as compared to conventional compression latches. 
     While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.