The present invention relates generally to latching devices and more particularly to latching devices for securing a first member such as a door, panel or the like in a closed position relative to a second member such as a corresponding door, panel or frame.
Various types of latching devices for use in securing a first closure member such as a door, panel or the like in a closed position relative to a corresponding second closure member such as a door, panel or frame are known. Some types incorporate a pawl or similar latching member that is actuated to engage a closure member for latching.
In certain applications, it is desirable to know whether the mechanism is in a latched or unlatched state. For example, latches used to secure the door of a baggage compartment of a coach bus or a train, for example, may be inspected prior to beginning a journey. If the latch is not properly locked, the stored luggage belonging to the passengers may be inadvertently lost, if the compartment door opens while in transit, or the baggage may be stolen during the excursion, if the storage compartment is not properly secured and left unattended.
In one aspect of the present invention, a latch mechanism is provided that comprises a housing, a cap, and at least one indicator. The cap may include a central axis and may be mounted for selective rotational movement relative to the housing about the central axis between a latched position and an unlatched position. At least one indicator may be interposed between the cap and the housing, such that the cap is covering at least a portion of at least one indicator. The at least one indicator may also be mounted for radial movement outwardly from the central axis relative to the cap as the cap is rotated from the latched position to the unlatched position such that the cap is no longer in a covering relationship to the portion of at least one indicator.
The above and other aspects and features of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
The invention will now be described by reference to exemplary embodiments and variations of those embodiments. 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 and described. 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.
According to various embodiments of the present invention, a latch mechanism is provided that comprises a housing and a cap configured to rotate relative to one another and cause one or more indicators that may, for example, be wing-shaped to extend as the latch mechanism is unlatched. The starting withdrawn position of the indicators may be closer to the central axis of the cap and/or housing when latched and extend out radially as the cap is rotated to the unlatched condition. The indicators may immediately pivot or otherwise move radially outwardly and reach their fully extended position, for example, within the first five degrees of rotation of the cap, and remain in the fully extended position for the remaining rotation of the cap to the unlatched condition. For example, if a 180 degree rotation of the cap will unlock the latch mechanism, the indicators may extend within the first five degrees of unlocking rotation of the cap and maintain the fully extended position for the remaining 175 degrees of rotation. It is preferred to configure the latch mechanism, such that the indicators reach their fully extended position and maintain this position for as much of the rotation of the cap as possible to eliminate the impression of a ‘false-locked’ condition in which the indicators are withdrawn, but the latch is not fully closed. The indicators may be color coded, such as a bright red color that may be generally visible at least 5 meters away, to warn an operator that the latch is not fully closed, which may be critical in transportation applications, such as on a train or moving vehicle. Springs or other biasing means are optional, but may be included in some embodiments, to facilitate actuation of the indicators. The indicator's motion may be completely controlled by the rotation of the cap or may be controlled by the housing geometry. Therefore, the indicators may pivot about an axis that is fixed relative to the cap or the housing, for example.
Referring now to
The latch mechanism according to the present invention may be provided in the form of various types of latches, such as a simple cam latch. The inner features of the latch may allow axial and/or rotational movement of the pawl. In one embodiment of the present invention, the latch mechanism may be provided in the form of a cam latch, such as the latch described in U.S. Pat. No. 6,640,592, the contents of which are incorporated herein by reference in its entirety. For example, the opposing second end 35 of the housing 26 may be provided with an opening, and a shaft 30, positioned at least in part within the housing 26, may extend through the opening. The shaft 30 may be operatively connected to the cap 24. A pawl 32 may be attached to an end of the shaft 30 using a fastening means, such as a screw 36. The outer surface of the housing 26 may also be provided with interrupted screw threads along a portion of the outer surface thereof. The screw threads on the outer surface of the housing 26 may be interrupted by two or more flats, preferably at least four flats, formed on the outer surface of the housing 26. The flats formed on the outer surface of the housing 30 prevent the rotation of the housing 26 when the key 22 is used to turn the cap 24, once the latch 20 is installed in a closure member such as a door or the door's frame. The interrupted threads on the outer surface of the housing 26 are engaged by a nut (not shown) to secure the latch 20 in place, once the latch 20 is installed in a closure member such as a door or the door's frame.
The cam latch may include a cam (not shown) having at least one cam slot. The cam may be rotatably supported within the housing 26, as well as operatively connected to the cap 24, so as to rotate in response to rotation of the cap 24 from the latched condition to the unlatched condition. The shaft 30 may include a cam follower located within the cam slot, which may be configured such that the shaft 30 and the pawl 32 rotate in unison and also shift axially away from the second end 35 of the housing 26 as the cap moves between the unlatched position and the latched position.
In order to indicate whether the latching mechanism is in the latched or unlatched condition, the one or more indicators 28 alternate between a withdrawn condition and an extended condition. For example in the withdrawn condition as provided in
It is preferred that the portion of the indicators that are no longer obscured be provided with a color that is different than the color of the cap, such that the indicators when extended are easily recognizable. The portion of the indicator therefore includes a visual enhancement feature. The visual enhancement feature can be a color, a light, a reflector, or any other indicator means that enhances visualization of the indicator. A reflective surface is particularly beneficial at night where a coach driver or a train inspector, for example, using a flashlight can quickly observe either the presence or absence of the reflecting indicator and determine whether one or more compartments are either latched or unlatched.
For example, in the embodiment of
In order to cause the one or more indicators to transition from a withdrawn position to an extended position when the cap is rotated, one embodiment of the present invention may include one or more grooves 46 in the top surface of a flanged portion 44 of the housing 26. Referring to
Referring specifically now to
As would be appreciated by those of skill in the art, the configuration of the groove 46 may also be modified, for example, by changing the angle of the angled section 54, such that the transition from the withdrawn position to the extended position of the indicator is less immediate. Also, the direction of the grooves 46 may be reversed, so that the indicators extend when the cap is rotated in the clockwise direction. This would allow selection of the appropriate status indicator to be incorporated in either a left- or right-handed latch depending on the desired indications in the latched and unlatched condition and latching rotation direction of the latch mechanism. It is preferred that the height from the bottom of the flange of the housing to the top surface of the cap is as short as possible to provide a latch mechanism having a head with a small profile. It is also preferred to provide a relatively deep groove in the housing flange. The peg should also be configured to have a sufficient height and thickness that is approximately the same depth and width of the groove, so that the peg remains positioned within the groove during actuation of the latch and there is no risk of the peg escaping from the groove. A symmetrical design as mentioned above comprising two indicators wherein each indicator is in a respective groove may also be configured, so that the indicators extend in sync during rotation of the cap. It is preferred to include two or more indicators arranged such that the indicators extend substantially about the entire perimeter of the cap when actuated, so that the unlatched condition of the latch is easily recognized from the exposed portions of the indicators. The indicators may also extend at an angle to the central axis of the cap, such that the extended position of the indicators may be recognized from the side of the latch mechanism.
An alternative embodiment of a latching mechanism according to the present invention is provided in
In some embodiments, the tip of the indicator 128 opposite to the bore may impinge on a portion of the cap 124 or the housing to prevent the indicator 128 from over extending. When the cap 124 is rotated back 180 degrees in the clockwise direction, the pin 152 will mate with notch 153 and a raised area 200 on the cap 124 adjacent to the pin 152 will push an end of the indicator 128 and urge the indicator 128 back to its original withdrawn position in the latched condition.
In other embodiments, the latching mechanism in
Another alternative embodiment of a latching mechanism 220 according to the present invention is provided in
There are several differences between the first embodiment and the third embodiment shown in
A sticker or decal 260 (
Despite the aforementioned differences, operation of the indicator 228, as well as the entire latching mechanism 220, is generally the same as that of indicator 28 and latching mechanism 20.
Like the latching mechanism 20 of
The cam 282 includes prongs 283 extending from the top end that are engaged with slots on the bottom side of the cap 224, such that the cam 282 rotates along with the cap 224. The cam 282 also includes one or more cam slots 285 defined on the revolved exterior surface.
The control sleeve 284 includes prongs 291 extending from the bottom end that are engaged with slots 293 (
In an assembled form of the latching mechanism 220, the cross-pin 288 is fitted through a cross-wise hole in the shaft 286, the slot(s) 287 of the control sleeve 284, and the cam slot(s) 285 of the cam 282. The free ends of the cross-pin 288 are positioned in a circumferential recess 289 (
The operation of the latch when installed as part of an assembly including a door or closure member, will now be described. When cap 224 is rotated, the sleeve-like cam 282 will be driven to rotate in the same direction as the cap 224. When cam 282 is rotated, cross pin 288 is moved, but whether the movement is axial or rotational is dependent upon whether the ends of pin 288 are in the axial slot portions 287a or in the circumferential slot portions 287b of the motion-control sleeve 284.
When in the latched position, the cap 224 is at its fully clockwise position, and the two opposite ends of cross pin 288 are positioned through the axial slot portions 287a of the motion-control sleeve 284, near the ends of the axial slot portions 287a. In addition, the portions of the cross pin 288 projecting from either side of the shaft 286, simultaneously engage the cam slots 285 of the cam 282. At the extreme of the clockwise rotation of the cap 224, the projecting portions of the cross pin 288 are positioned nearest to the ends of the cam slots 285 which are closest to the proximal end (i.e., the end closest to the cap 224) of the cam 282. The pitch of each of the cam slots 285 is such that the axial distance, i.e. the distance measured in a direction parallel to the longitudinal axis of the cam 282, between a location along the cam slot 285 and the proximal end of the cam 282 increases in the clockwise direction, beginning at the end of the cam slot nearest the proximal end of the cam 282.
To unlatch the closure member from a door frame (for example), cap 224 is turned in a counterclockwise direction. When this is done, cap 224 and cam 282 rotate as a unit. The cross pin 288 cannot move rotationally because its opposite ends are within the axial slot portions 287a of the stationary motion-control sleeve 284. As a result, when cam 282 is rotated counterclockwise, the opposite ends of pin 288 follow the opposed cam slots 285, and as a result, pin 288, and hence also shaft 286 and the pawl 299 (
After cap 224 and cam 282 have been rotated as a unit through approximately 120 degrees (for example), cross pin 288 has moved axially away from the proximal end of the motion control sleeve 284, and is now aligned with the opposed circumferential slot portions 287b. Further rotation of cap 224 and cam 282 now causes rotational movement of cross pin 288, shaft 286 and pawl 299, as the ends of pin 288 move along the opposed circumferential slot portions 287b. In this manner, pawl 299 is moved out of alignment with the door frame, and after approximately 60 degrees of rotation, the closure member or door is fully unlatched from the door frame. The cap 224 has now been rotated approximately 180° (for example) relative to its fully latched position.
The latching action is simply the reverse of the unlatching action just described. On latching, as cap 224 is turned clockwise, the opposite ends of cross pin 288 move in the clockwise direction along the circumferencial slot portions 287b and the shaft 286 rotates in the clockwise direction about its longitudinal axis. Then the cross pin 288 translates axially toward the proximal end of the motion control sleeve 284, when the cross pin 288 reaches the axial slot portions 287a. These sequential motions are caused by the walls of the cam slots 285, which urge the ends of the cross pin 288 along the circumferential slot portions 287b in the clockwise direction, until the ends of the cross pin 288 abut against the edge of the axial slot portions 287a. Thereafter, walls of the cam slots 285 urge the ends of the cross pin 288 axially toward the proximal end of the motion control sleeve 284 along the axial slot portions 287a. Thus, cam 282 and the motion-control sleeve 284 cooperatively cause the rotational and axial motions of the shaft 286 to take place in sequence, in response to the rotational motion of the cap 224 in the latching or clockwise direction, in one continuous motion.
It should be understood that the latching mechanisms 20 and 220 are not limited to the cam latch 280 that is shown and described herein. In other words, the indicators, caps and housings described herein may be utilized with other latch styles. For example, the indicator(s) may be used with an adjustable grip latch having an externally threaded rod, which is disclosed, for example, in U.S. Pat. Nos. 4,583,775 or 6,640,592, each of which is incorporated by reference herein in its entirety. The indicator(s) described herein may be used with a minimal protrusion fixed grip latch having an internally threaded shaft, which is disclosed, for example, in PCT Patent Application Pub. No. WO/2017/011443, which is also incorporated by reference herein in its entirety. As yet another example, the indicator(s) described herein may be used with non-compression cam latch (non-pull-up), which is disclosed, for example, in U.S. Pat. No. 8,336,931, which is incorporated by reference herein in its entirety. In the standard non-compression type cam latch, the pawl pivots between latched and unlatched positions without translating.
In the present embodiments, the components of the latch mechanism are preferably comprised of metal and metal alloy materials, however, other suitable materials can also be used where desired, such as plastic, aluminum, or zinc. In addition, in the present embodiment, the closure member can be comprised of any suitable materials, such as wood or metal, and can be of varying thickness.
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.
This application is a continuation patent application of PCT Patent Application No. PCT/US2017/020668, filed Mar. 3, 2017, which claims priority to U.S. Provisional Patent Application No. 62/303,112, filed Mar. 3, 2016, the disclosure of these applications being incorporated herein by reference in their entirety for all purposes.
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Number | Date | Country | |
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20170306651 A1 | Oct 2017 | US |
Number | Date | Country | |
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62303112 | Mar 2016 | US |
Number | Date | Country | |
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Parent | PCT/US2017/020668 | Mar 2017 | US |
Child | 15647750 | US |