Abstract:
An improved rotary latch and housing configured to receive a strike is described. The housing includes two parts that are mated together to improve their resistance to impact forces imparted by the strike. The housing is provided with a channel-shaped recess for receiving the strike. A rotary jaw and rotary pawl are disposed within the housing to secure the strike in a locked position and release the strike in an unlocked position.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to latches, and more particularly, to an improved rotary latch system.  
       BACKGROUND INFORMATION  
       [0002]     Rotary latch systems have been used in various applications for many years. Rotary latches are particularly useful in applications where a user slams shut a door or lid. For example, rotary latches are frequently used in automobiles to secure lift gates, doors, hoods, and lids. Rotary latches are also used to secure cabinet doors to cabinets. In automotive applications, rotary latch systems must withstand relatively high impact forces. Moreover, lift gates, doors, hoods, and lids are opened and closed (often forcefully) countless times during the life of an automobile. As a result, rotary latch systems must be long-lasting and hard-wearing.  
         [0003]     Typical rotary latches generally include a housing that contains a rotary pawl and a rotary jaw. The rotary jaw and housing include U-shaped notches for receiving a strike surface. In general, the pawl controls the jaw. Over the years, this type of latch has been improved numerous times and yet retains the same basic mechanism and function of original rotary latches.  
         [0004]     One previously known, slam-capable rotary latch mechanism is described in U.S. Pat. No. 5,844,948 (“&#39;948 patent”) entitled ROTARY LATCH AND LOCK and U.S. Pat. No. 5,564,295 (“&#39;295 patent”) entitled HANDLE OPERABLE ROTARY LATCH AND LOCK. In general, these patents describe a rotary latch having a pair of housing side plates that sandwich the rotary jaw and rotary pawl. The &#39;948 patent discloses housing side plates including formations extending toward a central plane (that is occupied by the rotary jaw and the rotary pawl) to guide and maintain proper positioning of one or both of the rotary jaw and the rotary pawl within the common central plane. Spacers are positioned transversely relative to the rotary jaw and rotary pawl. As described in the &#39;948 patent, the spacers are immovably attached to the housing side plates through hexagonal holes in the housing side plates. Additionally, one of the housing side plates is provided with an integrally formed reinforcement flange adjacent the strike-receiving portion of the housing side plate.  
         [0005]     Previously known slam-capable rotary latches, however, have a number of drawbacks. Many previously known rotary latches are subjected to relatively high shear forces generated as the strike slams into the latch and housing. Over time, the housing, rotary jaw and rotary paw fatigue and may jam or come apart, thus rendering the latch inoperable. While reinforcement flanges have been previously used to reinforce housing side plates, such flanges are not interconnected. As a result, such flanges provide limited support. In addition, manufacturing previously known slam-capable rotary latches can be unnecessarily difficult and time-consuming.  
       BRIEF SUMMARY  
       [0006]     The various preferred embodiments provide significant improvements and advantages over other rotary latches. According to a first aspect of the present invention, a rotary latch includes a housing having a first lateral wall and a first transverse wall extending from the lateral wall. The first transverse wall has a first projection. The housing further includes a second lateral wall, and a second transverse wall extending from the second lateral wall. The second transverse wall forms a recess adapted to receive the first projection. In various embodiments, the projection and recess can be configured as a tab and slot fitting or a dovetail fitting, for example and without limitation. In one embodiment the projection and recess are welded or secured together by an adhesive. The first lateral wall and the second lateral wall further define a channel configured to receive a strike.  
         [0007]     The foregoing paragraph has been provided by way of general introduction, and is not intended to limit the scope of the following claims. The presently preferred embodiments, together with further advantages will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:  
         [0009]      FIG. 1  illustrates a perspective side view of an exemplary rotary latch having a mated housing;  
         [0010]      FIG. 2  illustrates a perspective front view of an exemplary rotary latch having a mated housing;  
         [0011]      FIG. 3  illustrates a partially exploded top view of an exemplary rotary latch having a mated housing;  
         [0012]      FIG. 4  illustrates a cross-section of an exemplary rotary latch in an open position;  
         [0013]      FIG. 5  illustrates a cross-section of an exemplary rotary latch in a closed position; and  
         [0014]      FIG. 6  illustrates a perspective side view of an exemplary latch in a closed position having a linkage assembly. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     The invention is described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of this invention are better understood by the following detailed description. However, the embodiments of this invention as described below are by way of example only, and the invention is not limited to the embodiments illustrated in the drawings. It should also be understood that the drawings are not to scale and in certain instances details have been omitted, which are not necessary for an understanding of the present invention, such as conventional details of fabrication and assembly.  
         [0016]     Referring to the drawings,  FIGS. 1-5  illustrate an embodiment of the present invention, and in particular, a rotary latch  10 . Generally, rotary latch  10  includes a mated housing  18 , a latch mechanism  20 , and a control assembly  65 . Housing  18  is formed from two mated covers. Latch mechanism  20  is partly enclosed within housing  18 . Latch mechanism  20  generally includes a rotary jaw  36 , a rotary pawl  40 , sleeves  44 ,  48 , and a return spring  52 . The latch mechanism and the housing are adapted to receive and secure (or latch) strike  14 . Rotary latch  10  has an open position and a closed position. In the open position, the jaw is positioned to receive the strike and to rotate into a closed position. In the closed position, the strike is secured by the jaw and the housing. A control assembly generally includes a conventional key lock and a control linkage. The control assembly allows a user to open the latch.  
         [0017]     As best shown in  FIGS. 1-3 , housing  18  is formed from covers  22  and  25 . In particular, as illustrated in  FIG. 2 , cover  22  includes lateral wall  23  and transverse walls  24 . Likewise, cover  25  has a lateral wall  26  and transverse walls  27  that extend from lateral wall  26 . Accordingly, each transverse wall extends only part way across the distance between walls  23  and  24 , and is joined about a central region  110  ( FIG. 2 ) by a tab and slot configuration.  
         [0018]     The disclosed tab and slot configuration reinforces the housing, which is subjected to a variety of impact forces created as the strike slams into the latch. Transverse walls  24  include tabs  28  and transverse walls  27  of cover  25  are provided with slots  32 . As illustrated in  FIG. 2 , slots  32  are configured to mate with tabs  28 . As will be apparent to one of ordinary skill, the position of the slots and tabs can be switched, so that cover  22  has slots  32  and cover  25  has tabs  28 . The slots and tabs can alternatively be positioned at any point along the edge of the transverse walls. In another alternative embodiment, a dovetail configuration can be used rather than slots and tabs. A dovetail configuration prevents the covers from laterally separating along axis Z of  FIG. 1  once the covers are assembled. Multiple sets of tabs and slots or dovetail configurations can be provided on the transverse walls to further provide further reinforcement. In another embodiment, the transverse walls can be alternatively joined by an adhesive or by welding, rather than providing slots and tabs. In this configuration, housing  18  is formed from a unitary construction, rather than from two separate covers. As such, the housing is provided with unitary transverse walls that form bridging elements between lateral walls.  
         [0019]     As illustrated in  FIG. 3 , covers  22  and  25  both include strike channels  64 . Strike channels  64  have a relatively flat, squared lower surface that, depending on the shape of the strike, may receive the impact from strike  14 . Openings  33  are provided to receive sleeves  44  and  48 , which are discussed in greater detail below. Cover  22  further includes a floor  104  having openings  108 . When used in automotive applications, openings  108  are used to attach the housing to the body of the automobile. In addition, covers  22  and  25  are provided with flanges  76  and  77 , respectively, as best illustrated in  FIG. 3 .  
         [0020]     Referring to  FIG. 1 , housing  18  partly contains latch mechanism  20 . As further shown in  FIG. 3 , latch mechanism  20  generally includes a rotary jaw  36 , a rotary pawl  40 , sleeves  44 ,  48 , and a return spring  52 . Referring to  FIGS. 4-5 , housed between covers  22  and  25  are the jaw  36  and pawl  40 . Jaw  36  and pawl  40  are received over sleeves  44  and  48 , respectively, in a slip fit. This allows the jaw and the pawl to rotate around the sleeves. As noted above, sleeves  44  and  48  are disposed through openings  33  and secured thereto, for example, by staking the sleeves to the housing. The return spring  52  is preferably configured as a torsion coil spring, housed between covers  22  and  25 . Spring  52  has a first end  53  that engages jaw  36  and a second end  54  that engages pawl  40 . Return spring  52  creates a return force that biases the jaw and pawl toward an open position, as illustrated in  FIG. 4 .  
         [0021]     Referring to  FIGS. 4-5 , rotary jaw  36  has a strike recess  88  and a notch  100 . The strike recess is configured to receive the strike when the jaw is in an open position ( FIG. 4 ), and secure the strike when the jaw is in a closed position ( FIG. 5 ). Notch  100  is configured to engage jaw lock projection  92 , which is located on pawl  40 . Accordingly, when the jaw lock projection  92  of pawl  40  and notch  100  are engaged ( FIG. 5 ), jaw  36  is prevented from rotating into an open position ( FIG. 4 ). Additionally, notch  100  is configured to engage notch  102 , which is located on pawl  40 . Notch  102  thus prevents jaw  36  from rotating past an ideal open position.  
         [0022]      FIG. 1  illustrates control assembly  65 , which includes key lock  66 , arm  68  and arm  72 . Arm  68  is fixed to lock  66  so that arm  68  swivels as lock  66  is locked and unlocked. As shown in  FIG. 6 , arm  68  is attached to arm  72  by linkage  114 . Snap-fit connector  116  is used to secure linkage  114  to arm  68 . Arm  72  has a projection  73  that is configured to engage projection  96  of pawl  36  ( FIG. 4 ). Accordingly, arms  68  and  72  cooperatively link lock  66  to latch assembly  22 .  
         [0023]     In operation, rotary latch  10  has two main positions-unlatched and latched.  FIG. 4  illustrates the unlatched position. When rotary latch  10  is unlatched, jaw  36  extends outwardly relative to housing  18 . In particular, strike recess  88  is positioned to receive the strike and rotate into the latched position.  FIGS. 1-2  illustrate the latched position. In the latched position, strike  14  is trapped or latched between strike recess  88  and housing assembly  18 . To move the rotary latch into a latched position, the strike must be moved into strike recess  88  with sufficient force to overcome the return force created by spring  52 . As noted above, when in a latched position, projection  92  of pawl  40  prevents the rotation of jaw  36 . A user can release the strike by keying lock  66  into an unlocked position.  
         [0024]     The embodiments described above and shown herein are illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description and attached drawings. The invention may be embodied in other specific forms without departing from the spirit of the invention. For example, the housing can be formed from more than two parts, or alternatively as a single, integral structure. Likewise, numerous linkages can be provided between the lock and the latch. In addition, the shape and construction of the associated jaw and pawl structures could be varied while still achieving the required functionality. Likewise, the shape of the strike channel could be varied while still achieving the required functionality. Accordingly, these and other changes which come within the scope of the claims are intended to be embraced herein.