Single action latch

[0001] The present invention is directed generally to latches for securing a lid or cover to an underlying tray. More particularly, the invention is directed to a latch for releasably securing a cover to a sterilization case.

[0002] The sterilization of medical instruments is an important factor in preventing infection and the spread of disease. In this regard, specialized sterilization cases have been developed to facilitate sterilization of instruments and other articles. One such sterilization case includes a tray or receptacle for receiving the instruments to be sterilized, and a lid for enclosing the open top of the receptacle. The receptacle may include a series of apertures formed in the bottom thereof to permit the passage of sterilizing media and air into the case. Typically, such cases are wrapped in a specialized non-woven filter material or a launderable fabric which is held in place by an indicating tape or other closure which indicates that the case has gone through a sterilization process. The wrapper permits the passage of sterilizing media and air therethrough, but prevents the passage of microbial contamination.

[0003] In a typical procedure, instruments to be sterilized are placed in the sterilization case which is then covered by the lid. The lid is ordinarily held in place on the receptacle by one or more latches. The closed case is then wrapped in the specialized paper and subjected to a sterilization process. Following sterilization, the case may be stored for a short period of time or brought directly to an operating room, unwrapped and the lid removed to provide access to the instruments. Following the surgical procedure, the instruments are normally returned to the receptacle and the lid assembled thereon so that the instruments may be transported to an appropriate destination for cleaning and re-sterilization.

[0004] In the foregoing procedure, it is important that the latches securely hold the lid in place on the receptacle in order to avoid accidental contamination of the sterilized instruments, damage to the instruments or possible injury to medical personnel. More particularly, during the handling of the cases both before and after sterilization, the cases may be banged into one another or into tables, storage racks and the like. The impact on the cases, or on the latch itself, could cause the latch to open. The latch could also open as a result of vibrations during the sterilization process or during transport of the case. The opening of the latch may not be appreciated when the case is wrapped in sterilization paper. As a result, when the case is subsequently unwrapped, the instruments may fall out of the receptacle and become contaminated or damaged.

[0005] Another potential problem with available sterilization cases is that the latches may inadvertently be opened as the user grasps the handles to lift the case. That is, in some of these cases, the actuating mechanism for opening the latch is positioned close to the handles for the case and is exposed for easy operation. A user grasping the handles to lift the case may inadvertently operate the actuating mechanism, releasing the latch so that the lid is no longer held securely to the receptacle. This can be particularly problematic following a surgical procedure where instruments contaminated with blood and other body fluids are being transported. Should the lid come off of the receptacle during such transport, the instruments could fall out of the case and be damaged or possibly cause injury.

[0006] In view of the foregoing problems, there exists a need for an improved latch for a sterilization case which is easily opened, but which remains in place when secured in a locked condition so as to minimize the possibility that the latch will be opened accidentally or inadvertently.

[0007] The present invention addresses these needs.

[0008] One aspect of the present invention provides a latch for use on a container having a tray and a lid for covering the tray. According to this aspect of the invention, the latch includes a base attached to the tray, an engaging member pivotably attached to the base and operable between a latched position for securing the lid to the tray and an open position in which the lid is separable from the tray; and an actuator pivotably attached to the base and operable between a locked position for locking the engaging member in the latched position, and a release position for releasing the engaging member for movement to the open position. Preferably, the engaging member has a first pivot axis, and the actuator has a second pivot axis parallel to the first pivot axis.

[0009] The engaging member has an abutment surface arranged to travel in a movement path on movement of the engaging member between the latched position and the open position, and the actuator has a projecting member which lies in the movement path in the locked position to prevent movement of the engaging member from the latched position to the open position. In the release position, the projecting member of the actuator lies outside of the movement path to release the engaging member for movement from the latched position to the open position.

[0010] In preferred embodiments, the actuator is positioned between the engaging member and the tray, the engaging member including an opening providing access for operation of the actuator. Where the engaging member includes an opening, the actuator may include an operating member accessible through the opening.

[0011] In highly preferred embodiments, the latch may further include a resilient member operable to exert a force on the engaging member for moving the engaging member from the latched position to the open position upon movement of the actuator from the locked position to the release position. The resilient member may be further operable to move the actuator from the release position to a rest position, which may be the same as the locked position. Desirably, the resilient member may include at least one coil spring. The coil spring may include a first leg exerting a force against the engaging member and away from the actuator and a second leg exerting a force against the actuator and away from the engaging member. The engaging member may have a pivot axis and the coil spring may be coiled about the pivot axis.

[0012] In another preferred embodiment, the actuator may be further pivotable from the release position to a stop position. In accordance with this embodiment, the actuator may have a pushing surface operable to contact the engaging member at about the release position of the actuator and to push the engaging member toward the open position upon movement of the actuator from the release position toward the stop position.

[0013] Another aspect of the present invention provides a storage case including a tray having a bottom, side walls and an open top; a lid for enclosing the open top of the tray; and at least one latch for securing the lid to the tray. The latch in accordance with this aspect of the present invention may have any of the features of the latch described above.

[0014] A further aspect of the present invention provides a latch for holding a cover to a structure defining an opening. According to this aspect of the invention, the latch includes a base attached to the structure, an engaging member pivotably attached to the base and operable between a latched position for securing the cover to the structure and an open position in which the cover is separable from the structure; and an actuator pivotably attached to the base and operable between a locked position for locking the engaging member in the latched position, and a release position for releasing the engaging member for movement to the open position. The latch in accordance with this aspect of the invention may have any of the features of the latch for a container as described above.

[0015] A still further aspect of the present invention provides a method for holding the lid of a container in assembled relationship to the tray of the container and for releasing the lid for separation from the tray. In accordance with the method, a latch is provided having an engaging member operable between a latched position for holding the lid to the tray and an open position in which the lid is separable from the tray, and an actuator operable between a locked position for locking the engaging member in the latched position and a release position for releasing the engaging member for movement to the open position. Moving the engaging member from the open position to the latched position causes the actuator to move to the locked position, the actuator in the locked position being located between the tray and the engaging member. Subsequently moving the actuator from the locked position to the release position causes the engaging member to move from the latched position to the open position. Releasing the actuator causes the actuator to move from the release position to a rest position which may be the same as the locked position.

[0016] A more complete appreciation of the subject matter of the present invention and the various advantages thereof can be realized by reference to the following detailed description in which reference is made to the accompanying drawings in which:

[0017] FIG. 1 is a perspective view of a sterilization case incorporating the latch of the present invention;

[0018] FIG. 2 is a partial exploded view showing the latch of FIG. 1;

[0019] FIGS. 3A-3D are cross-sectional views showing the operation of the latch of FIG. 1; and

[0020] FIG. 4 is an enlarged partial cross-sectional view with the coiled spring removed to show the interaction of the actuator and the engaging member during the release of the latch of FIG. 1.

[0021] For the purpose of describing the features of the present invention, the improved latch is discussed in association with a well-known type of medical sterilization case. It will be appreciated, however, that the improved latch of the present invention may be used with other types of medical sterilization cases or containers, as well as other types of devices in which a cover or lid is to be releasably held to a tray or other container. Such uses may include, for example, tool boxes, fishing tackle, luggage, foot lockers, lockers, storage boxes and other such containers. The improved latch of the present invention may also be used in conjunction with various other structures and devices in which a cover or lid is to be held in place over an opening, such as hatches, electrical panels, control panels and the like.

[0022] One embodiment of the sterilization case 10 with which the latch of the present invention may be used is illustrated in FIG. 1. Case 10 generally has a construction which is similar to sterilization cases known in the art, and includes a base portion or receptacle 12 and a top portion or lid 14 which is releasably held to receptacle 12 by a pair of latches 20 (only one of which is illustrated), one mounted on each end of receptacle 12. Although case 10 is shown with a generally rectangular shape, it may be configured in a variety of different shapes and sizes, as desired. Preferably, however, receptacle 12 is formed with relatively flat end walls, such as end wall 16, to facilitate the attachment of latches 20 thereto. A series of perforations (not shown) may be formed in the bottom surface of receptacle 12 to permit the passage of sterilizing media and air therethrough.

[0023] Lid 14 has a substantially flat top surface 22 which terminates in a downwardly curved peripheral edge 24. The size and shape of lid 14 are configured to enclose the open top of receptacle 12.

[0024] One of latches 20 is shown in more detail in the exploded view of FIG. 2. Latch 20 generally includes an engaging member 30 which holds the lid 14 to receptacle 12 in a latched position, and an actuator 110 which locks engaging member 30 in the latched position and releases engaging member 30 for movement to an open position.

[0025] Engaging member 30 has a generally flat central portion 32 with a pair of side members 34 and 36 projecting in the same direction away from central portion 32. Side member 34 includes a generally rectangular aperture 38, and side member 36 includes a generally rectangular aperture 40 (FIG. 4), the purpose of which will be described below. A hook portion 42 extends from an upper edge of central portion 32 and terminates in a curved free end 44. Hook portion 42 is sized to extend up and over curved edge 24 of lid 14, whereby the free end 44 thereof can engage the top surface 22 of lid 14 to hold case 10 in a closed condition. In order to open case 10, latches 20 are released so that lid 14 may be removed from receptacle 12. The release of latches 20 enables the hook portion 42 of each latch to pivot away from the top surface 22 of lid 14, thereby enabling the lid to be lifted from receptacle 12. A large, generally rectangular aperture 46 formed in central portion 32 of engaging member 30 provides finger access to actuator 110, as will be described hereinbelow.

[0026] At their upper ends, side members 34 and 36 terminate in upwardly projecting fingers 48 and 50, respectively. Finger 48 has an inclined edge 52 and a substantially vertical edge 54 which meet at an apex 55. Edge 54 is spaced relative to edge 42a of hook portion 42 so as to define a notch 56 between the hook portion and finger 48. More particularly, edge 42a of hook portion 42 is spaced from finger 48 so as to define a gap therebetween in a direction parallel to the plane of the hook portion. Additionally, edge 54 is spaced from hook portion 42 so as to define a gap therebetween in a direction substantially perpendicular to the plane of the hook portion.

[0027] Similarly, finger 50 has an inclined edge 62 and a substantially vertical edge 64 which meet at an apex 65. Edge 64 is spaced relative to edge 42b of hook portion 42 so as to define a notch 66 between the hook portion and finger 50. Thus, edge 42b of hook portion 42 is spaced from finger 50 so as to define a gap therebetween in a direction parallel to the plane of the hook portion. In addition, edge 64 is spaced from hook portion 42 so as to define a gap therebetween in a direction substantially perpendicular to the plane of the hook portion.

[0028] Engaging member 30 is pivotally mounted to receptacle 12 by a pair of spaced-apart generally L-shaped brackets 80 and 90 connected to receptacle 12. Bracket 80 has a first portion 82 bolted, riveted, welded or otherwise joined to end wall 16 of receptacle 12, and a second portion 84 projecting outwardly therefrom. Similarly, bracket 90 has a first portion 92 joined in a similar manner to end wall 16 of receptacle 12 and a second portion 94 projecting outwardly therefrom. A conventional bail handle 95 may be pivotably mounted to brackets 80 and 90 in a known fashion. Bail handle 95, in conjunction with a similar bail handle (not shown) mounted on the other end of receptacle 12, facilitates the carrying and maneuvering of case 10.

[0029] A shaft 100 extends through aperture 35 in side member 34 and an axially aligned aperture (not shown) in side member 36, and has its ends journaled in corresponding apertures 86 and 96 in bracket portions 84 and 94, respectively, thereby permitting engaging member 30 to pivot relative to brackets 80 and 90 about an axis substantially parallel to end wall 16. A pair of tabs 88 and 98 projecting inwardly from bracket portions 84 and 94, respectively, reside in apertures 38 and 40 of engaging member 30 when the engaging member is assembled between brackets 80 and 90. Tabs 88 and 98 each have a width which is narrower than the width of apertures 38 and 40, thereby enabling engaging member 30 to pivot relative to brackets 80 and 90, but limiting the range of the pivoting movement. In particular, as engaging member 30 is pivoted outwardly away from end wall 16 of receptacle 12, tabs 88 and 98 will engage the inner sides 38a and 40a of apertures 38 and 40, respectively, preventing further outward movement.

[0030] A second shaft 102 mounts actuator 110 for pivoting movement between bracket portions 84 and 94. Actuator 110 has a central portion 112 with a pair of side walls 114 and 116 projecting in the same direction away from the central portion at the ends thereof. Side walls 114 and 116 include axially aligned apertures 118 and 120 for receiving shaft 102, the ends of which are journaled in corresponding apertures 89 and 99 in bracket portions 84 and 94. A tab 122 projects outwardly from the upper portion of side wall 114 toward but spaced from bracket portion 84. Tab 122 is sized and positioned so as to be receivable in notch 56 in the locked condition of latch mechanism 20, thereby lying in the path of movement of finger 48 to prevent engaging member 30 from moving to the open position. Another tab 124 projects inwardly from the bottom of side wall 114 and includes an aperture 126, the purpose of which will be described below.

[0031] Side wall 116 includes a tab 128 projecting outwardly from the upper portion thereof toward but spaced from bracket portion 94. Tab 128 is sized and positioned so as to be receivable in notch 66 in the locked condition of latch mechanism 20, whereby tab 128 lies in the path of movement of finger 50, preventing engaging member 30 from moving to the open position. Another tab 130 projecting inwardly from the bottom of side wall 116 includes an aperture 132, the purpose of which will also be described below.

[0032] Actuator 110 further includes a depending operating member 136 which, in the assembled condition of latch 20, projects away from end wall 16 of receptacle 12 toward aperture 46 in engaging member 30. As will be described below, in the locked position of latch 20, operating member 136 is accessible for a user to release the latch by inserting one or more fingers through aperture 46. Preferably, operating member 136 is accessible to the user only through aperture 46, thereby assuring that actuator 110 is always operated in the same way.

[0033] Latch 20 may further include one or more resilient members for urging engaging member 30 to the open position when released by actuator 110. Thus, referring to FIG. 2, latch 20 may include a pair of coil springs 140 and 142 mounted between engaging member 30 and actuator 110. Spring 140 has a pair of elongated legs 140a and 140b, with a coiled portion 140c therebetween. Similarly, spring 142 has a pair of elongated legs 142a and 142b, with a coiled portion 142c therebetween. Spring 140 may be mounted on shaft 100, preferably just interior of side member 34, with leg 140b projecting upwardly through aperture 126 in actuator 110 and leg 140a lying in the junction between side member 34 and central portion 32. In a similar manner, spring 142 may be mounted on shaft 100, preferably just interior of side member 36, with leg 142b projecting upwardly through aperture 132 in actuator 110 and leg 142a lying at the junction between side member 36 and central portion 32. Springs 140 and 142 not only bias engaging member 30 toward the open position, they also bias actuator 110 toward end wall 16. In that regard, actuator 110 is mounted to bracket portions 84 and 94 so that the central portion 112 thereof is positioned close to end wall 16. As a result of this positioning and the biasing forces exerted by springs 140 and 142, actuator 110 will achieve a rest position when central portion 112 abuts end wall 16. Moreover, the biasing forces exerted by springs 140 and 142 create a frictional force between tabs 122 and 128 and fingers 48 and 50, respectively, thereby preventing latch 20 from accidentally coming out of the latched position on tilting, jarring or vibration of case 10.

[0034] The operation of latch 20 will now be described with reference to FIGS. 3A-3D. FIG. 3A shows latch 20 in the latched position in which hook portion 42 of engaging member 30 extends up and over curved edge 24 of lid 14 to hold lid 14 in a closed position against receptacle 12. In this latched position, engaging member 30 is held in place by actuator 110. More particularly, actuator 110 is in its rest position with the central portion 112 thereof biased against the end wall 16 of receptacle 12, with tab 122 of actuator 110 residing in notch 56, and tab 128 residing in notch 66, thereby locking hook portion 42 in position and preventing it from pivoting away from the end wall of the receptacle. Of particular note, actuator 110 in this latched position resides entirely behind engaging member 30, and therefore cannot accidentally be operated by an impact from another case or similar object. Furthermore, this position of actuator 110 prevents it from being operated inadvertently as a user grasps bail handles 95 to lift or maneuver case 10.

[0035] To release engaging member 30 for movement to the open position so that lid 14 may be removed from receptacle 12, a user inserts one or more of his or her fingers through aperture 46 in engaging member 30 and lifts operating member 136 of actuator 110 as indicated by arrow A in FIG. 3B. As actuator 110 pivots on shaft 102, tabs 122 and 128 move upwardly until the actuator reaches the release position in which the tabs clear apex 55 of finger 48 and apex 65 of finger 50, respectively. With tabs 122 and 128 no longer restraining engaging member 30 from movement, the biasing force exerted by springs 140 and 142 forces engaging member 30 away from end wall 16 of receptacle 12. In addition, as actuator 110 is pivoted, edge 124a of tab 124 and edge 130a of tab 130 contact central portion 32 of engaging member 30 on either side of aperture 46, exerting a further outward force on engaging member 30. Thus, even if springs 140 and 142 were to be omitted, be broken or otherwise fail to exert a sufficient outward biasing force on engaging member 30, the pivoting movement of actuator 110 would cause engaging member 30 to pivot outwardly from the latched position to the open position. Engaging member 30 will continue to pivot outwardly until it reaches the fully open position shown in FIG. 3C in which tabs 88 and 98 engage the inner sides 38a and 40a of apertures 38 and 40, respectively, acting as a stop to prevent further outward movement. With engaging member 30 in the open position, the free end 44 of hook portion 42 is spaced from lid 14, thereby permitting its removal from receptacle 12.

[0036] Once engaging member 30 has reached the open position, actuator 110 may be released, whereupon springs 140 and 142 will bias the actuator back to its rest position, as shown in FIG. 3D. As is evident from the figure, the biasing forces exerted by springs 140 and 142 are sufficient to hold engaging member 30 in the open position as they pivot actuator 110 back to its rest position.

[0037] Latch 20 is easily returned from the open position to the latched position to hold lid 14 on receptacle 12. With lid 14 properly assembled on receptacle 12, a user simply pushes engaging member 30 inwardly against the force of springs 140 and 142 until the free end 44 of hook portion 42 lies over the curved edge 24 of the lid. As engaging member 30 is pushed inwardly, inclined edge 52 of finger 48 will contact the bottom edge of tab 122 and inclined edge 62 of finger 50 will contact the bottom edge of tab 128. As engaging member 30 continues to move inwardly, tabs 122 and 128 will be forced upwardly by inclined edges 52 and 62, thereby causing actuator 110 to pivot in the direction of arrow A. Actuator 110 will continue to pivot in the direction of arrow A upon inward movement of engaging member 30 until tabs 122 and 128 clear the apex 55 of finger 48 and the apex 65 of finger 50. At that point, the biasing force exerted by springs 140 and 142 will cause actuator 110 to pivot back toward its rest position, whereupon tabs 122 and 128 will fall into notches 56 and 66, respectively, locking engaging member 30 in the latched position.

[0038] It will be appreciated that latch 20 may be varied in several respects while still achieving the advantages of the present invention. In one such variant, case 10 may be provided with a hinge for hingedly connecting lid 14 to receptacle 12 along one side or end edge of the container. In such embodiment, one or more latches 20 may be provided on the side or end of the container opposite the hinge to hold the lid in the closed condition.

[0039] In another variant, latch 20 may be provided with a single spring having sufficient biasing force to bias engaging member 30 and actuator 110 as described above. Where one or more springs are used in latch 20, the springs need not be in the form of a coil spring, but may be in the form of any resilient member providing a biasing force to engaging member 30 and actuator 110. For example, the springs may be in the form of a leaf spring, a coiled compression spring or the like, or in the form of a resilient mass, such as a body of rubber, elastic bands or the like. Alternatively, latch 20 may be provided with no springs, such that the pivoting movement of actuator 110 would push engaging member 30 to the open position as described above. Where no springs are used, actuator 110 would be returned to the rest position manually once engaging member 30 has reached the open position. Further, since the biasing forces exerted by springs 140 and 142 help to hold latch 20 in the latched position, where no springs are used, latch 20 preferably includes a conventional retaining pin or a secondary latch to prevent latch 20 from becoming accidentally unlatched.

[0040] Although latch 20 as described above includes an actuator 110 having a pair of tabs 122 and 128, and an engaging member having a pair of notches 56 and 66 for receiving tabs 122 and 128, it will be appreciated that the latch may be formed with an actuator having a single tab and an engaging member having a single notch for receiving the tab.

[0041] In those applications in which latch 20 is not used for holding lid 14 to a receptacle 12, engaging member 30 may have an element configured differently from hook portion 42. That is, engaging member 30 may have a hook portion 42 which has a different shape than that of free end 44 so as to correspond to the shape of the lid being held in place. Alternatively, engaging member 30 may be formed with a portion similar to hook portion 42, but which includes pins receivable in holes in a structure being held in place, or tabs receivable in slots in the structure being held in place. Still other configurations of engaging member 30 may be devised depending upon the particular application for the latch 20.

[0042] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as set forth in the appended claims.