The hinge includes pivotally interconnected door and frame wings for mounting a cabinet door for swinging between open and closed positions on a cabinet frame. A substantially J-shaped latching finger is formed integrally with the door wing and coacts with a cam on the frame wing to releasably latch the door as the door is swung to its closed position.

BACKGROUND OF THE INVENTION 
This invention relates to a hinge for mounting a door such as a cabinet 
door for swinging between open and closed positions on a frame such as a 
cabinet. The invention more specifically relates to a so-called knife 
hinge having door and frame wings with blade-like portions which are 
received in a slot in the door. With wings of this type, the hinge is 
fully concealed from the front of the cabinet, and only a small portion of 
the hinge is visible from the hinged edge of the door when the door is in 
its closed position. 
A knife hinge of this general type is disclosed in Youngdale et al U.S. 
Pat. No. 3,203,031. That hinge is a self-latching hinge in that it 
includes a mechanism for automatically latching the door as the door 
reaches its closed position and for thereafter releasably holding the door 
in the closed position. The Youngdale et al hinge, however, is relatively 
expensive in that the self-latching mechanism requires multiple 
components. In addition to the cost of the components themselves, there 
are significant costs involved in assembling the components with one 
another and with the remainder of the hinge. 
SUMMARY OF THE INVENTION 
The general aim of the present invention is to provide a new and improved 
self-latching knife hinge which, when compared with prior hinges of the 
same general type, is significantly easier to manufacture and is quieter 
in operation. 
A more detailed object of the invention is to achieve the foregoing by 
providing a hinge in which the latching mechanism of the door wing is 
defined by a single component which is formed integrally with the door 
wing so as to eliminate multiple components and the need for assembling 
the same. 
In still a more specific sense, the invention resides in a knife hinge in 
which a resiliently yieldable latching finger is formed integrally with 
the door wing and coacts uniquely with a cam on the frame wing to 
releasably hold the door in its closed position. 
These and other objects and advantages of the invention will become more 
apparent from the following detailed description when taken in conjunction 
with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
For purposes of illustration, the knife hinge 10 of the present invention 
has been shown in the drawings in conjunction with a cabinet such as a 
kitchen cabinet 11 having a base 12 with a front frame member 13 which 
defines part of the front opening of the cabinet. The hinge mounts an 
upright door 14 on the frame member for swinging between open and closed 
positions about a vertical axis. An identical hinge (not shown) is spaced 
vertically from the hinge 10 and also is connected between the door and 
the frame member. 
The hinge 10 includes frame and door wings 15 and 16 which are attachable 
to the frame 13 and the door 14, respectively. The frame wing 15 is 
stamped and formed from metal and basically is of conventional 
construction. It includes an upright mounting plate 17 adapted to lie 
face-to-face with the inboard side of the frame member 13 and formed with 
a slot 18 (FIG. 7) and a hole 19 for receiving screws 20 (FIG. 1) which 
fasten the frame wing 15 to the frame member. Formed integrally with and 
projecting horizontally from the lower margin of the plate 17 is a 
blade-like lug or tab which defines a cam 21. An ear 22 (FIGS. 2 and 8) is 
integral with one end of the cam 21 and is formed with a vertically 
extending hole 23 (FIG. 8) for receiving a pivot member such as a rivet 24 
(FIG. 4). The rivet pivotally interconnects the frame wing 15 with the 
door wing 16. 
As shown most clearly in FIGS. 1 and 5, the door wing 16 also includes an 
upright mounting plate 25 which lies face-to-face with the rear side of 
the door 14. Screws 26 (FIG. 1) extend through a slot 27 (FIG. 5) and a 
hole 28 in the plate 25 to secure the door wing 16 to the door 14. 
Formed integrally with and projecting forwardly from the lower margin of 
the mounting plate 25 of the door wing 16 is an ear 30 (FIG. 5) which is 
disposed in a horizontal plane. A hole 31 is formed in the free end 
portion of the ear and, when the hinge 10 is assembled, the hole 31 is 
located in vertical alinement with the hole 23 in the frame wing 15 and 
receives the rivet 24. Thus, the rivet pivotally interconnects the two 
wings 15 and 16. 
As shown in FIGS. 2 and 4, a slot 33 is formed in the rear face of the door 
14 and opens out of the hinged edge thereof. The ears 22 and 30 of the 
wings 15 and 16 are located in the slot as is the rivet 24. When the door 
is fully closed as shown in FIG. 4, the entire hinge 10 is concealed from 
the front of the cabinet 11. Only a small portion of the hinge is visible 
from the hinged edge of the door. As the door is opened and closed, the 
ear 30 scissors back and forth across the ear 22 in the manner of a 
conventional knife hinge. 
In knife hinges, it is known to provide a self-latching mechanism for 
holding the door 14 releasably in its closed position. According to the 
present invention, the door wing 16 is constructed with an integral 
self-latching device 40 which reduces the cost of manufacturing a 
self-latching knife hinge and also reduces the noise produced as the 
device latches and unlatches. 
More specifically, the door wing 16 is made of a single piece of 
resiliently yieldable material, the door wing preferably being injection 
molded from plastic such as Acetal. In carrying out the invention, the 
latching device 40 takes the form of a substantially J-shaped finger. 
Along most of its length, the finger 40 is spaced rearwardly from and is 
disposed in opposing relation with the mounting plate 25 of the door wing 
16. The end of the finger nearest the rivet 24 is a free end and is formed 
by a rounded nose 41 which extends forwardly from the finger when the door 
14 is closed. The opposite end portion of the finger 40 is integrally 
hinged to the mounting plate 25 by a generally C-shaped section 42 (FIG. 
6) of plastic. As a result of the hinge section 42, the finger 40 is 
supported cantilever fashion on the plate 25 to flex toward and away from 
the rear face of the door 14. 
As shown in FIG. 2, the nose 41 of the finger 40 engages an edge 44 of the 
cam 21 when the door 14 is partially open. The edge 44 is irregularly 
shaped and defines a cam surface. When the door is opened beyond the 
position shown in FIG. 2, the nose 41 of the finger 40 pulls away from the 
cam surface 44 but, as the door is reclosed, the nose re-engages the cam 
surface. With further closing of the door, the nose rides along the cam 
surface and, due to the shape of the cam surface, the finger 40 is flexed 
rearwardly and resiliently away from the door as permitted by the C-shaped 
hinge section 42. As the door reaches its fully closed position, the nose 
41 encounters a pocket 45 at the end of the cam surface 44. By virtue of 
the resiliency of the flexed finger 40, the nose 41 snaps into the pocket 
45 upon final closing of the door and thereafter coacts with the pocket to 
releasably latch the door closed. When a substantial opening force is 
applied to the door 14, the finger 40 flexes rearwardly to cause the nose 
41 to pop out of the pocket 45 and permit opening of the door. 
When the door wing 16 cools after being molded, shrinkage of the plastic 
tends to cause the free end portion of the latching finger 40 to warp 
toward the mounting plate 25. To prevent excessive warpage, a short 
horizontally extending post 50 (FIGS. 5 and 6) is molded integrally with 
the mounting plate and extends horizontally therefrom into engagement with 
the forward side of the nose 41. Accordingly, the post 50 maintains a 
minimum spacing between the nose and the mounting plate as the door wing 
cools and prevents the finger from warping in toward the mounting plate. 
The post is located well above the elevation of the cam 21 and thus does 
not interfere with the latching and unlatching action. For clarity of 
illustration, the post has been omitted from FIGS. 1 to 4. 
From the foregoing, it will be apparent that the present invention brings 
to the art a new and improved knife hinge 10 in which a latching finger 40 
is formed integrally with a door wing 16 so as to eliminate the cost of 
multiple latching components. While the door wing and the latching finger 
have been specifically disclosed as being made of plastic, it will be 
appreciated that a one-piece metal component could be produced. Plastic is 
preferred, however, from the standpoint of lower cost, smoother and 
quieter operation, better durability and more color selections.