Latching mechanism for cap tailgate door

A single T-handle latching mechanism including a center T-handle, a rotor assembly, a right and left swivel connector, a right and left rod rotator, a right and left lock rod with rotator engagement and a latching contoured end, and a right and left engagement latch plate. An approximately 90 degree rotation of the T-handle will extend the lock rods out to the right and left. With this mechanism, the lock rods also rotate about their axis approximately 180 degrees, with the contoured rod end pulling a door closed as its extension proceeds and, finally, at full extension latching the door securely closed in an engagement latch plate against its frame and sealing, not only in its longitudinal axis, but also in its frontal and horizontal axis.

FIELD OF THE INVENTION 
This invention relates to a latching system for a tailgate door on a pickup 
topper. 
BACKGROUND OF THE INVENTION 
Latches used on tailgate doors (described as the rear gate door) are hinged 
at the top and close downwardly and shut against a pickup tailgate, on a 
pickup "topper", or other equivalent "RV" application, and are of two 
common types: double T-handle and single T-handle with lock-rods. 
The double T-handle is two T-handles, one affixed to each side of the 
door's lower edges, and each provided with a latch blade that engages 
against a beveled latch plate affixed to the door frame. Rotating the 
T-handles approximately 90 degrees pulls the door shut against the door 
frame and weather seals the door, securing the door in its closed 
position. 
The single T-handle with two lock rods is a single T-handle mounted at the 
bottom center of the door, provided with a rotor assembly. The two 
lock-rods are connected to the rotor and extend out to each side, through 
a rod guide adjacent to the door edge. Again, a beveled latch plate is 
provided on the door frame at each side. 
Rotating the single center T-handle approximately 90 degrees then extends 
the lock-rods outwardly, both right and left, engaging rods against the 
latch plates and securing the door in a closed position against the door 
frame, and weather sealing the door frame. 
Security: Because of their design, a locked door can be breached by simply 
spreading the lower corners of the cap, or by applying enough force at the 
handle to bend and/or distort the lock-rods or their guides. 
Because toppers are of reasonable lightweight construction, when handled 
during manufacture, shipping, or storage, they tend to lose their fit and 
dimension at the lower rear portion. This is due to spreading or bending 
of the sides, thus affecting quality and/or requiring extra handling care 
and expense, etc. Also, spreading of the sides of the topper is caused, 
during use, due to vehicle vibration and general wear nd tear. 
SUMMARY OF THE INVENTION 
The object of this invention addresses shortcomings and defects of the 
above-described mechanisms. 
By the present invention, a single T-handle latching mechanism includes a 
center T-handle, a rotor assembly, a right and left swivel connector, a 
right and left rod rotator, a right and left lock rod with rotator 
engagement and a latching contoured end, and a right and left engagement 
latch plate. 
An approximately 90 degree rotation of the T-handle will extend the lock 
rods out to the right and left. With this mechanism, the lock rods also 
rotate about their axis approximately 180 degrees, with the contoured rod 
end pulling the door of the topper closed as its extension proceeds and, 
finally, at full extension latching the door securely closed in an 
engagement latch plate against its frame and sealing, not only in its 
longitudinal axis, but also in its frontal and horizontal axis. This 
provides greatly improved security to the user with a fixed and unaltering 
register of the door and door frame at the manufacturer, and, 
additionally, providing a strong, three-way positioning hold for handling, 
shipping, storage, display, and general use. 
Alternately, the rotor, swivel connectors, and rod rotator may be combined 
into one central device. Also, the same rod rotators may be used with a 
levered center handle in place of a T-handle and rotator. 
It is therefore an object of the present invention to provide a latching 
mechanism for securing a door of a pick-up topper to the sides of the 
topper by engagement of a contoured end of a lock rod in a complementary 
shaped engagement latch plate which is secured to the side of a frame for 
the door. 
It is another object of the present invention to provide a latching 
mechanism for securing a door of a pick-up topper to the sides of the 
topper by engagement of a contoured end of a lock rod in complementary 
shaped engagement latch plate which is secured to the side of a frame for 
the door and having a central, single T-handle which is moved through 
90.degree. to shift opposed locking rods through 180.degree. of rotation 
with simultaneous lateral extension to lock the contoured ends within the 
latch plates. 
It is yet another object of the present invention to provide a latching 
mechanism for securing a door of a pick-up topper to the sides of the 
topper by engagement of a contoured end of a lock rod in a complementary 
shaped engagement latch plate which is secured to the side of a frame for 
the door and having a central single T-handle which is moved through 
90.degree. to shift opposed locking rods through 180.degree. of rotation 
with simultaneous lateral extension to lock the contoured ends within the 
latch plates and a pin located on the locking rod being rotated through a 
rod rotator and engaging a terminal wall of a spiral groove of the rod 
rotator upon complete turning of 90.degree. of the T-handle and 
simultaneous engagement of the latching of the contoured ends in the latch 
plates to prevent further lateral extension of the locking rods and 
preventing pulling of the door out of its frame by engagement of the 
contoured ends in the latch plates. 
These and other objects of the invention, as well as many of the intended 
advantages thereof, will become more readily apparent when reference is 
made to the following description taken in conjunction with the 
accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In describing a preferred embodiment of the invention illustrated in the 
drawings, specific terminology will be resorted to for the sake in 
clarity. However, the invention is not intended to be limited to the 
specific terms so selected, and it is to be understood that each specific 
term includes all technical equivalents which operate in a similar manner 
to accomplish a similar purpose. 
With reference to the drawings, in general, and to Figure 1, in particular, 
a latching mechanism embodying the teachings of the subject invention is 
generally designated as 10. With reference to its orientation in FIG. 1, 
the latching mechanism is used for securing a door 12 with a window 14 at 
the rear end of a pickup topper or enclosure 16 having side windows 18. 
The enclosure rests upon the side walls 20 of the payload or bed section 
of a pickup truck with the door 12 located above the tailgate 22 of the 
pickup truck. 
A frame 24 surrounding the door 12 includes portions attached to the side 
walls and ceiling of the enclosure. The door 12 is pivotally 
interconnected with the frame by hydraulic piston cylinders 26. An upper 
end of the hydraulic piston cylinders 26 is secured at 28 to the door 12 
while the lower end is secured to the frame 24 at 30. Part of the door 12 
is located below the window 14 is a reinforcing panel 32. Panel 32 moves 
with the window 14 upon opening of door 12. 
Mounted on an interior side of the panel 32 is rotor assembly 34. Extending 
from the rotor assembly, which is centrally located on panel 32, is left 
swivel connector 36 and right swivel connector 38. Threaded into swivel 
connectors 36 and 38 are left locking rod 40 and right locking rod 42, 
respectively. Locking rods 40, 42 extend through left rod rotator 44 and 
right rod rotator 46, respectively Mounted on frame 24, which is fixed to 
the enclosure 16, are left engagement latch plate 48 and right engagement 
latch plate 50. 
Rotor assembly 34 is shown in greater detail in FIG. 7 as including base 
plate 52, rotor 54 and cover 56. The base plate is secured to the panel 32 
by screws 58 passing through holes 59 in the cover 56 passing through the 
base plate and into the panel 32. Screws 58, on the other side of the 
panel 32, are secured to mounting plate 61 of T-handle 62. 
All three of the base plate, rotor and cover include a central opening with 
the center of the rotor 54 including a square-shaped opening 66 through 
which passes a square-shaped stem 60 of T-handle 62, shown in FIG. 6, and 
secured in place by a cotter pin 64 passing laterally through the stem 60. 
A circular portion 68 of the rotor 54 is shown extending through an 
opening 70 of the cover 56. 
Rotor 54 includes two opposed arms 72 extending from circular portion 68 
and having upstanding projections 74 at the terminal end of the arms 72. 
The projections 74 engage within openings of swivel connectors 36 and 38 
for opposed lateral movement of the swivel connectors 36, 38 away from the 
rotor assembly. 
Respective ends 76, 78 of left and right locking rods 40, 42 are threaded 
and are threadingly engaged within swivel connectors 36 and 38, 
respectively. The swivel connectors are maintained secured to the 
projection 74 by extending through a gap formed between the cover 56 and 
base plate 52, as shown in FIG. 6. 
Towards the outermost lateral end of locking rods 40 and 42 is located a 
transversely extending rotator engager or roll pin 80 extending through 
and perpendicular to the locking rods 40, 42. Pin 80 is positioned on the 
locking rods within rod rotators 44 and 46. Rod rotators 44 and 46, as 
shown in FIG. 4, are fixed in position on panel 32 by screws 82. 
The rod rotators include a central bore 84 through which the locking rods 
40, 42 slide. The roll pin 80 extending through each of the locking rods 
travels within a spiral groove 86 of the rod rotators, extending radially 
outwardly from central bore 84, in a spiral configuration. 
At the opposite end of locking rods 40 and 42 from ends 76, 78 is hook 
shaped portions 88, 90, respectively, serving as a latching contoured end. 
The latching contoured ends are bent to an angle of less than 90.degree. 
so as to have a slight hooking appearance. 
Spaced laterally outwardly from the contoured end 88, 90 are engagement 
latch plates 48, 50. The latch plates are secured to the sides of the 
frame 24 by screws 91. 
With reference to FIG. 9, left engagement latch plate 48 is shown having 
flat portion 93 with two projection portions 92 and 94 defining a gap 96 
therebetween. The gap 96 is shaped complementary to the contoured ends 88 
and 90 of the locking rods to receive the contoured ends of the locking 
rods when the contoured ends extend upwardly. The contoured hook-shaped 
portions 88, 90 curve around projection portion 92 so as to draw the latch 
plates inwardly toward the rotor assembly. 
In operation, the latching mechanism begins in the open position, as shown 
in solid lines in FIGS. 1 and 7, and in dotted lines in FIG. 2, with the 
terminal portions of the contoured ends 88, 90 pointing in a downward 
direction. In this position, the door 12 may be swung open away from the 
enclosure 16 and tailgate to gain access to the bed of the pickup truck. 
Upon rotation of the T-handle 62 through substantially 90.degree., the 
square shaped stem 60 engaged in the opening 66 of rotor causes the rotor 
to move from the position shown in FIGS. 1 and 7 to the position shown in 
solid lines in FIG. 2. The swivel connectors 36, 38 anchored on the 
projections 74 of the arms 72 of the rotor are moved with the rotor by the 
T-handle to cause outward lateral movement of the swivel connectors away 
from the rotor assembly. The locking rods threadingly engaged at ends 76, 
78 in the swivel connectors are also, therefore, moved laterally outwardly 
away from the rotor assembly. 
The roll pin 80 of each locking rod is caused to move within the spiral 
groove 86 of each rod rotator 44, 46. Locking rods 40, 42 are thereby 
rotated through 180.degree. of movement and spun within swivel connectors 
36, 38 with simultaneous outward lateral movement. Latching contoured ends 
88, 90 are thereby moved outwardly and turned from a downward position to 
an upward position and into gap 96 of the engagement latch plates 48, 50 
as shown in solid lines in FIG. 2. In this closed position, 
weatherstripping engages the upper edge of the tailgate 22 to prevent 
access of the elements to the interior of the enclosure 16. 
In the closed position of the latching mechanism, the roll pin 80 is 
located at the end wall 100, as shown in FIG. 4, of the spiral groove 86. 
In this position, it is impossible to continue to force the continued 
turning of the T-handle 62 in the closing direction due to the engagement 
by the roll pin with the end wall 100. This prevents forcible breaking of 
the T-handle of the door 12 so as to prevent unwanted entry. Further, 
pulling outwardly on the T-handle in an attempt to force the locking rods 
away from the frame is prevented by the secure engagement of the contoured 
ends 88, 90 within the gap 96 of the latch plates 48, 50. Also, during the 
movement of the contoured ends 88, 90 into the gaps 96 of the latch plates 
48, 50, the sides of enclosure 16 are drawn inwardly by the contoured ends 
extending around curved portion 102 of projection 92 of the latch plates. 
Therefore, in the closed position, several different counteracting forces 
are applied to secure the door 12 in the frame 24 of the enclosure 16 for 
locking of the door. 
Having described the invention, many modifications thereto will become 
apparent to those skilled in the art to which it pertains without 
deviation from the spirit of the invention as defined by the scope of the 
appended claims.