Patent ID: 12252917

DETAILED DESCRIPTION

A rear perspective view of an illustrative embodiment of a vehicle, such as pickup truck1, is shown inFIG.1. This view depicts truck1having a passenger compartment3and a cap5covering the truck's rear bed. Cap5also includes illustrative doors7and9which swing open to allow access to the interior of the rear bed. Vehicle door latch assembly2is shown on door7and9to secure and lock said doors to vehicle1. Actuating latch2releases the door to allow it to swing or otherwise move to the open condition. When latch2is latched and locked, the door is prevented from opening unless force can be applied to the latch and/or lock to overcome the locking function of the lock.

A front perspective view of vehicle door latch assembly2is shown inFIG.2. These latches are commonly used on compartment doors for commercial and industrial vehicles, such as lifts and work trucks, to secure the compartment door or the like. Typically these latches, from the operator's point of view, include a main housing4with a pivotable handle6that is both recessible in and extendible from housing4. During operation, handle6is pivoted upward in direction8. Handle6is attached to shaft16so both are rotatable in the same direction12. This causes pawl18with latch tab20attached thereto to rotate in direction12and unlatch the door (not shown). Conversely, to relatch the door, handle6is turned in direction14which likewise turns shaft16which rotates pawl18and latch tab20in direction14. Tab20reengages a securement (not shown) on the periphery of the compartment opening to latch the door (also not shown) closed. With the door latched, handle6may be pushed downward in direction10into cavity22of housing4so as not to become an obstruction while operating the vehicle. To lock latch assembly2, a lock cylinder assembly24extends through housing4and is engageable with a key (not shown) which rotates between lock and unlock conditions. The problem with this design is that the rotational force that can be applied to shaft16from handle6may be stronger than what the structure associated with lock cylinder assembly24can withstand. This makes the locking system vulnerable.

An embodiment of the present disclosure herein includes a tether structure30(seeFIG.3) that provides the needed strength so that excessive force on shaft16will not be able to overcome the locking and latching features. It is contemplated that security tether30is able to be added to latch assembly2as an add-on. This makes the fix both relatively simple and affordable in contrast to purchasing complete new latch assemblies.

A rear perspective view of vehicle door latch assembly2is shown inFIG.3. This view further shows pawl18, latch tab20, and lock cylinder assembly24. Also shown is lock lever26located in unlocked and latched conditions. It is appreciated that the key that turns a portion of lock cylinder24rotates lock lever26between locked and unlocked conditions. The locked condition is configured (as further disclosed herein) to lock pawl18keeping it from moving. This view also shows the head portion of bolt28which is attached to the aforementioned shaft16to provide the pivot point for pawl18.

What is new to latch assembly2is the addition of security tether30with bolt28and spacer90. This tether couples to both shaft16and lock lever26about lock cylinder assembly24to prevent excessive rotational force on shaft16from breaking lock cylinder24, thereby lock lever26unlocking and unlatching latch assembly2.

A rear perspective view of a prior art version of latch assembly2is shown inFIGS.4through6. These views do not include security tether30. As shown inFIG.4, pawl18locates latch tab20in the latched condition. Additionally, lock cylinder assembly24has pivoted lock lever26in a locked condition. In this state, lock lever26is positioned in cavity32formed in pawl18. Cavity wall portion34is configured to engage lock lever26such that if an attempt is made to rotate pawl18in direction12, lock lever26engages cavity wall portion34preventing that movement from happening. As can be appreciated, however, overcoming that engagement between lock lever26and cavity wall portion34is all that is needed to overcome the locking function. It is further appreciated that pawl18is formed out of a piece of relatively thin metal so the force needed to overcome that engagement is not all that great. The prior art view inFIG.5shows lock lever26in the unlocked condition. Pawl18and tab20are still located in the latched condition, but they are free to rotate if shaft16is rotated. The prior art view inFIG.6shows handle6rotated, which rotates shaft16and pivots pawl18and tab20in direction12to an unlatched condition. It is appreciated from this view that tab20simply needs to be moved to this position to unlatch the door. Overcoming lock lever26is all that is needed to unlatch assembly2without a key.

An exploded view of vehicle door latch assembly2that includes security tether30is shown inFIG.7. As depicted, handle6is pivotally coupled to shaft16via handle rivet36disposed through coincident openings38and40. To seal shaft16from exterior to interior, shaft gasket42, along with shaft cover gasket44and shaft cover48, surround shaft16. Housing4includes a bore opening50that receives shaft16so it can be located on both the front and rear side of latch2. Also shown is lock cylinder assembly24that extends through cylinder gasket52and bore54in housing4to extend between front and rear sides of housing4. A flange54includes openings56and58and is secured onto housing4via rivet60. A hex nut62secures lock cylinder assembly24to housing4and lock lever26secures to lock cylinder24via e-ring64. Shaft16also extends through opening58of flange54and secures to latch2via shaft e-ring66and bolt28. Pawl18pivotally secures to latch assembly2via shaft16that extends through opening68. A washer70may be disposed about shaft16between pawl18and flange54to assist in pivotal movement of same. Rod posts74and76are configured to attach to pawl18, as well as lock rods78and80. Set screws82secure rods78and80to posts74and76, respectively. A cam rivet84is secured to pawl28in order to limit pawl18's movement.

Security tether30, having openings88and92disposed therethrough, is coupled to latch assembly2via bolt28. A spacer90, as well as bolt28, spaces apart tether30from pawl18and cam washer86(see alsoFIG.13).

There are essentially three failure modes for the prior art version of latch assembly2. The first is where the axes of both shaft16and lock cylinder24splay themselves apart when pawl18is rotated in direction12. This is caused by wall portion34of pawl18pushing against lock lever26when force is being applied towards direction12. Another failure mechanism is when a force on pawl18is applied in direction12causing wall portion34of pawl18to engage lock lever26causing excessive force on retainer106and e-ring64. This torsion force causes both structures to fail which essentially allows lock lever26to “pop” off of lock cylinder24. This allows pawl18to be moveable. A third failure mechanism occurs when applying excessive force against pawl18in direction12, causing wall portion34of pawl18to apply a force against lock lever26. But instead of retainer106failing, the internal locking structures in lock cylinder24strip, thereby causing lock lever26to be moveable to the unlocked condition and allowing pawl18to move and unlatch. The embodiments of the security tether keep the axis of shaft16(with bolt28) and lock cylinder24substantially parallel to each other under excessive force preventing the first failure mechanism as described above. In addition, the tethers absorb the force applied to lock lever26by wall portion34of pawl18, thereby preventing the failure of lock lever26by either the second or third failure mechanisms described above.

Front perspective views of embodiments of security tethers30,100, and105are shown inFIGS.8A,8B, and8Crespectively. These security tethers may be made of a solid piece of metal, such as steel, aluminum, brass, or other materials, such as high density polyethylene or a laminate. Openings88and92receive the lock cylinder and shaft, respectively, as previously discussed. As part of opening88, there is a lever slot portion94that receives lock lever26. Slot portion94is configured to accommodate rotational travel of lock lever26between locked and unlocked conditions. By providing a strengthened tie between shaft16and lock cylinder24, forced rotation of shaft16can no longer overcome lock lever26. Each of the embodiments30,100, and105shown inFIG.8includes opening88and slot portion94terminating at edges96. In addition, along the periphery of opening88are wall portions107and108.

Edge96on lever slot portion94now receives the force of lock lever26instead of the force received by retainer106and e-ring64. This means first, there is a strong reinforcement to hold the locked condition, and second, any strong forces applied to edge96through shaft16will cause a failure at the shaft instead of at the lock, and particularly at the pawl. Accordingly, any failure due to excess force will not occur at the pawl nor the retainer and clip and, thus, not move latch tab20.

Surface107on the embodiments keeps the tether positioned against the lock cylinder24(see alsoFIGS.4and9) so that if an excessive force applied to pawl18in direction12causes wall portion34to act on lock lever26, edge96engages lock lever26, but that force is offset by engagement of surface107against lock cylinder24. Surface108in the embodiments keep shaft16/bolt28and lock cylinder24substantially parallel to prevent them from splaying. If any excessive force is applied to handle6, shaft16will only strip-out or break those structures, while latch2remains latched.

Security tether100is similar to that shown in embodiment30except that opening88and slot94are shifted in order to accommodate a lock cylinder of different configuration. This embodiment shows opening98configured to accept a 20 degree lock lever. It is appreciated that the angle of opening98may be set to any degree and is not limited to a 20 degree lock lever.

Security tether105included inFIG.8with tether30is another embodiment having an “open” version where part of the material forming slot94has been removed. In any event, the wall portions95,107, and108are still there and serve the same functions as those portions in tethers30and100.

Rear perspective views of assembly2, as shown inFIGS.9through11, are similar to the prior art views ofFIGS.3through5except with security tether30attached to shaft16via bolt28. Also, tether30is located about the periphery of lock cylinder24with lever slot portion94accommodating lock lever26. As shown inFIG.9, lock lever26is located in the locked condition with pawl18and tab20located in the latched condition. In this view, it is appreciated that if shaft16attempts to rotate pawl18in direction12, lock lever26engages edge96of tether30which will prevent any movement. The views inFIGS.10and11demonstrate how security tether30does not interfere with lock lever26as lock cylinder24moves it to the unlocked condition (seeFIG.10). Handle6rotates pawl18in direction12to move tab20to the unlatched condition. In other words, the operation of latch2may progress as normal without any interference from security tether30. It is only when forced movement of shaft16attempts to break open latch2does security tether interfere with operation of pawl18and lock lever26.

Latch assembly2, shown inFIGS.12through14, depicts security tether30coupled thereto from different angles. It is appreciated from these views that security tether30is configured to just slide over lock cylinder24and secure onto shaft16via bolt28. Accordingly, retrofitting current similar-type latches is a relatively easy task.

The views shown inFIGS.15A through15Cdemonstrate what happens if excessive force is applied to shaft16in order to break latch2. InFIG.14A, shaft16is located in opening68of pawl18. In this illustrative embodiment, both this portion of shaft16and its corresponding opening68are square-shaped. It is appreciated that in other embodiments they are not limited to square shape. With security tether30in operation, it is shaft16that strips out while pawl18does not move. The view shown inFIG.14Bdepicts the result of applying too much force to shaft16with security tether30in place. It is appreciated that this view has removed security tether30for illustrative purposes to show what happens to shaft16and opening68as a result of an applied break-in force. A detailed view of shaft16and opening68inFIG.14Cdemonstrates how both structures are stripped out so that shaft16can rotate with respect to opening68yet not move pawl18. When this happens, rotation of shaft16will fail to rotate latch tab20which maintains itself in a latched condition.

Illustrative dimensions of an embodiment of security tether30are shown inFIGS.16A and16B. It is appreciated that these dimensions are illustrative. It is further appreciated that the position of the openings may be changed based on the desired configuration of the latch and lock assembly it is attaching to.

The figures and descriptions provided herein may have been simplified to illustrate aspects that are relevant for a clear understanding of the herein described devices, systems, and methods, while eliminating, for the purpose of clarity, other aspects that may be found in typical devices, systems, and methods. Those of ordinary skill may recognize that other elements and/or operations may be desirable and/or necessary to implement the devices, systems, and methods described herein. Because such elements and operations are well known in the art, and because they do not facilitate a better understanding of the present disclosure, a discussion of such elements and operations may not be provided herein. However, the present disclosure is deemed to inherently include all such elements, variations, and modifications to the described aspects that would be known to those of ordinary skill in the art.

Although certain embodiments have been described and illustrated in exemplary forms with a certain degree of particularity, it is noted that the description and illustrations have been made by way of example only. Numerous changes in the details of construction, combination, and arrangement of parts and operations may be made. Accordingly, such changes are intended to be included within the scope of the disclosure, the protected scope of which is defined by the claims.