Power latch system

A powered latching mechanism includes a threaded pin which engages an opposed pair of rotating dogs maintained within a keeper assembly driven by an electric motor connected to the header of the windshield. The dogs are configured to have a ramped portion which permits the manual urging of the pin therepast in the event of failure of the electric motor and/or the hydraulics of the convertible top.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention concerns automotive latching systems. More 
particularly, the present invention concerns powered latching systems. 
Even more particularly, the present invention concerns powered latching 
systems for convertible tops, trunk lids, tonneau covers and the like. 
2. Prior Art 
Heretofore, there has been proposed, powered latch systems for convertible 
tops and the like for use in automotive applications. However, in prior 
art systems there was a tendency for the latching pins to be 
cross-threaded, to bind up and to otherwise render such power systems 
unusable necessitating expensive repair. Moreover, such prior art systems 
had no ability to catch on the latch without first energizing the motor. 
Moreover, such prior art systems required alignment of the pin with the 
latching mechanism to relatively close precision, lest the system be 
rendered inoperative. Furthermore, if the power supply failed, in such 
prior art systems, it was virtually impossible to manually latch the 
convertible top to the automotive body. 
It is to be appreciated that in modern automotive technology and with the 
increasing popularity of convertible tops that such prior art systems have 
deficiencies which render such convertible automobiles less than 
desirable. 
In the present day market both male and female purchasers are attracted to 
the acquisition of such vehicles. Without a powered latch system which 
overcomes the problems encountered in the prior art the attractiveness of 
such vehicles, especially to the female purchaser, is somewhat detracted. 
As will subsequently be detailed, the present invention provides a power 
latching system which overcomes the deficiencies in the power art. 
SUMMARY OF THE INVENTION 
In accordance with the present invention there is provided a power latch 
system which includes a rotatable cylinder operatively connected to the a 
means, such as an electric motor for rotating the cylinder, a pair of 
opposed clogs or dogs which are disposed within the cylinder and which are 
substantially horizontally stationarily mounted therein, and a pin 
engageable by the dogs, which threadingly interconnects to the cylinder 
upon the rotation thereof when the pin contacts the clogs. 
In accordance herewith, the clogs are substantially opposed ramp surfaces 
having a specific configuration. The clogs are configured such that they 
can engage the pin in both a vertical and skewed orientation. This permits 
the motor to threadingly engage and latch down the pin even if it does not 
approach the cylinder in a precise vertical orientation, thereby 
overcoming any tendency to jam or the like. 
The pin, likewise, has a specific thread configuration which, in 
cooperation with the ramp configuration, permits both vertical and skewed 
alignment for threading interengagement. Likewise, the pitch of the pin is 
such that upon failure of the motor to rotate the cylinder, the pin can be 
manually urged past the clogs to permit manual latching. 
For a more complete understanding of the present invention reference is 
made to the following detailed description and accompanying drawing. In 
the drawing like reference characters refer to like parts throughout the 
several views in which:

DESCRIPTION OF THE PREFERRED EMBODIMENT 
At the outset, it is to be noted that although the present invention will 
be described with reference to a convertible top for a vehicle, the 
present invention evidences other utility wherever a powered pull down 
latching arrangement is desired. For example, in an automobile 
environment, in addition to latching convertible tops, the present 
invention is useful in latching powered trunk lids, deck lids and the 
like. Likewise, the latching assembly hereof can be used to tie down the 
rearwardmost bow in a convertible-type vehicle. 
Referring now to the drawing, and in particular, FIG. 1, there is depicted 
therein an automobile 10 having a convertible or foldable top 12. As is 
known to those skilled in the art to which the present invention pertains, 
such convertible or foldable tops, generally, comprise a fabric covering 
secured to a plurality of bows or struts which traverse the width of the 
vehicle and are foldable rearwardly and forwardly through a plurality of 
linkages which interconnect the various bows or struts which carry the 
fabric. The actual constrution of the convertible top and the linkage 
system for the folding and unfolding thereof does not form part of the 
present invention, per se. 
Referring again to the drawing, and in particular, FIGS. 1, 2, 5 and 9 
there is depicted therein a power latch assembly in accordance with the 
present invention and, generally, denoted at 19. The power latch assembly 
includes a pin member or latch pin, generally, denoted at 20. The latch 
pin comprises a shank portion 22 and a mounting bracket portion 24 
integrally formed therewith. 
The shank portion is a substantially cylindrical member 26 having an 
external, helical thread formed therearound. The helical thread is adapted 
to threadingly engage a keeper assembly 34, as detailed subsequently. In 
order to be efficacious within the concept of the present invention, the 
threaded portion of the shank 22 has a pitch ranging from about 45.degree. 
to about 60.degree. and has a diameter of about 0.48 to 0.52 inches. 
The bracket 24 comprises a substantially planar member 30 having at least 
one slot 32 (a pair of which are shown) formed therein. In the embodiment 
shown in the drawing the bracket engages the header bow of the convertible 
top 12 and receives a threaded fastener 33 through the slot 32 and the 
fastener 33 threadingly interengages or fastens to the header bow to mount 
the latch pin 20 thereto. The slot permits adjustment or positioning of 
the latch pin for proper alignment in order to be threadingly engaged with 
the keeper assembly 34. 
Referring now to FIGS. 2, 3, 4, 5 and 6, there is depicted therein the 
keeper assembly or keeper hereof, generally, denoted at 34. The keeper or 
latching assembly 34 is mounted to the windshield header 36 of the vehicle 
by any suitable mode. Ordinarily, a decorative housing 37 encompasses the 
keeper for aesthetic purposes only. 
The latching assembly or keeper 34, generally, comprises a means for 
rotating such as an electric motor 38. The motor is a conventional 12 volt 
dc motor having a rotatable output shaft 40. 
A worm gear 41 is formed externally on the output shaft of the motor and, 
as is subsequently detailed, cooperates with a ring gear 42 to cause 
horizontal rotation of an opposed pair of the latching members. 
The electric motor is powered by the vehicle, per se, through electrical 
connection to the alternator or battery in a manner well known to those 
skilled in the art. A switch (not shown) is interposed the motor and the 
source of power thereof to render the motor operative. 
Connected to the motor 38 is a housing assembly, generally denoted at 44 
which contains or houses the latching members for the pin 20. 
The housing 44 includes a mounting bracket 46 which threadably 
interconnects the housing 44 to the motor 38. The worm gear 41 projects 
outwardly from the motor and into the housing 44. 
The housing 44 includes a substantially cylindrical member 48 having an 
open top and open bottom. An opening 50 is formed in the side wall of the 
member 48 and through the opening 50 the worm gear 41 projects. 
Axially vertically mounted within the member 48 is a cylindrical 
open-interiored ring gear 42. The ring gear 42, as will subsequently be 
detailed, causes rotation of a pair of opposed clogs or dogs or latching 
members upon the causal rotation of the ring gear 42 by its engagement 
with the worm gear 41. 
The ring gear 42 seats within the member 48 and is freely rotatable 
therewithin. 
A hollow cylindrical barrel 52 has a reduced diameter portion which seats 
into the open interior of the ring gear 42 and is rotatable therewith. The 
barrel has an annular flange 54 which seats atop the ring gear and has a 
diameter substantially equal thereto. Superposed the flange 54 is an 
enlarged plate 56 which is integrally formed with the barrel 52 and the 
flange 54. The enlarged plate 56 has a central opening 58 which permits 
the pin 20 to project therethrough. The plate 56 acts as a seat for the 
latch members in a manner to be described subsequently and is also 
referred to as seat 56 herein. 
Seated upon the plate 56 are the latching members defined by a pair of 
opposed ramped clogs or dogs 60, 60'. The ramped dogs 60, 60' have a 
inclination of about 15.degree. and, at the innermost tip thereof, have an 
inclination of about 45.degree., as shown in FIGS. 7 and 8. Because of the 
configuration of the ramp portion of the dogs, the threaded shank 26 of 
the latch pin 20 cooperates to threadingly interengage therewith. 
Likewise, because of the angle of inclination of the ramp portions 60a and 
60b, the shank 26 can be manually passed thereby in order to manually 
latch the pin to the keeper assembly. 
As shown in the drawing, a biasing member, such as a coiled spring 62 
envelopes the opposed dogs and urges them toward the central aperture 58 
into which the shank 26 projects upon latching. 
A top plate 64 seats atop the opposed dogs and has a central opening 66 
through which the shank 26 projects. A pair of opposed threaded apertures 
68, 70 receive threaded fasteners 72 (only one of which is shown) to 
threadably interconnect the top plate 64 to the seat 56. 
As shown in FIG. 3, the seat 56 has a flange 74 having a central threaded 
opening 76 which receives the threaded fastener 72. Thus, upon threaded 
interconnection of the top plate 64 to the seat 56 the dogs 60, 60' become 
housed therebetween. The height of the dogs is slightly less than the 
height between the upper surface of the seat 56 and the lower surface of 
the top plate 64 to permit some slight vertical movement therebetween. 
Furthermore, a recess is formed in the lower surface 81 of the top plate 
64. The recess provides a positive lock for the dogs as follows. When the 
shank is held by the dogs the forces exerted thereby act against the 
spring and cause both an outward force as well as an upward force on the 
dogs. The upward force urges the dogs into the recess of the undersurface 
81 to positively retain the dogs therein. 
As clearly shown in FIG. 3, the barrel 52 has an annular groove 78 formed 
therearound at the bottom of the reduced diameter portion. A snap ring 80 
fits in the groove to hold the barrel within the member 48 in order to 
define a unitary assembly. 
In operation, the electric motor starts the rotation of the worm gear 41, 
which in turn, because of its meshing interengagement with the ring gear 
42, causes rotation of the barrel and the dogs, so that the ring gear, 
barrel, and dogs rotate as a unit. The latch pin is brought into the entry 
opening or entryway 66 via suitable hydraulics associated with movement of 
the convertible top and upon further downward movement engages the 
rotating dogs. The vertical and lateral forces caused by the shank act 
against the termini of the ramps and exert a sufficient force to act 
against the spring 62 to urge the dogs out of the entryway and to 
threadably interengage the threaded portion of the shank. The inward 
biasing force of the spring 62 maintains the dogs in engagement with the 
threaded portion to positively lock the shank in the keeper assembly. 
Reversal of the motor and reverse rotation of the assembly causes the pin 
to withdraw from the entryway 66. 
Also, and as above noted, because of the geometry of the ramped portions of 
the dogs, in the event that the hydraulics should fail, the shank can be 
urged past the dogs and be positively engaged therewith for positive 
manual latching.