Seat belt buckle

A safety belt coupling device includes a buckle having a hollow body provided with a front tongue receiving opening and an upwardly projecting latch member having an inclined front face. A coupling tongue having a front latch opening is slideable through the tongue receiving opening over the latch member to bring the latch opening into engagement with the latch member. A transverse lock bar is longitudinally movable between a lock position overlying the free end of the latched tongue to prevent the raising thereof and an unlock position rearward of the tongue free end to permit unlatching of the tongue and is biased to its unlock position. The lock bar lies in the path of the raised tongue free end and a finger actuated release member upon depression retracts the bar to its unlock position, and in one form includes a member rockable about a transverse axis and having cam slots engaging the lock bar, and in another form includes a longitudinally slideable push member lost motion coupled to the lock bar.

BACKGROUND OF THE INVENTION 
The present invention relates generally to improvements in vehicle safety 
belt devices and it relates more particularly to an improved vehicle 
safety belt buckle or coupling device. 
Safety or restraint belts have been extensively employed for the occupants 
of the seats of automobiles and other transport facilities to minimize any 
injury to the passengers attendant to accidents. Conventional buckles for 
seat belts of this kind are largely of the type in which a handle provided 
on the buckle body is elevated to release from the buckle the coupling 
tongue piece fastened to the end of the belt. However, buckles of this 
type were complex in construction and posed many problems unsolved from 
the viewpoint of workability and calling for improvement. 
In view of such circumstances, extensive research has been conducted by the 
present inventor in an attempt to improve buckles of various types, and he 
has previously proposed a buckle for seat belts having high safety 
performance, by which a certain portion of the buckle is depressed by a 
finger to release the engagement between the buckle and the tongue piece, 
replacing the elevating motion of a handle of the conventional devices. 
While the resulting buckle structure had some advantages, it possessed 
numerous disadvantages. It was a somewhat bulky, awkward and complicated 
device, difficult and expensive to fabricate and assemble, and otherwise 
left much to be desired. 
It is accordingly a principal object of the present invention to provide an 
improved vehicle safety belt device. 
Another object of the present invention is to provide an improved vehicle 
safety belt coupling device. 
Still another object of the present invention is to provide an improved 
vehicle safety belt buckle. 
A further object of the present invention is to provide an improved device 
of the above nature characterized by its high reliability, ruggedness, 
simplicity, compactness, ease and convenience of use, low cost of 
manufacture and assembly, and great versatility and adaptability. 
The above and other objects of the present invention will become apparent 
from a reading of the following description taken in conjunction with the 
accompanying drawings which illustrate preferred embodiments thereof. 
In a sense, the present invention comtemplates the provision of an improved 
safety belt buckle for use with a coupling tongue having a latch opening 
in which the buckle includes a body having a base wall and longitudinally 
spaced side walls having parallel longitudinal slots, the base wall being 
provided with an upwardly directed latch member which releasably engages 
the coupling tongue latch opening, the tongue leading end being insertable 
into the body member to bring the latch opening into vertical registry 
with the latch member and being vertically movable to bring the latch 
opening and member into releasable engagement. A transversely extending 
lock bar or pin extends between and has its ends slideably engaged by the 
side wall slots and lies in the longitudinal path of the raised leading 
end of the inserted coupling tongue and is longitudinally movable between 
positions rearward of and overlying the leading end of the tongue to 
define unlock and lock positions respectively, and is spring biased to its 
lock position. A finger operated release member is selectively actuatable 
to move the lock bar to its unlock position and may be in the form of a 
slide member coupled to the lock bar by a lost motion coupling or a 
swingably supported member having cam surfaces engaging the lock bar. The 
release member is spring biased to a retracted position. 
The improved buckle is simple, inexpensive, rugged, reliable, easy and 
convenient to operate, highly compact, simple to manufacture and of great 
versatility and adaptability.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, particularly FIGS. 1 to 5 thereof which 
illustrate a preferred embodiment of the present invention, the reference 
numeral 1 generally designates a coupling tongue piece and 2 the frame or 
body of the buckle that accepts the leading end of the tongue piece 2 
through a front opening in the frame for coupling and uncoupling the 
tongue piece to the buckle. The tongue piece has formed proximate its 
leading or free end a latch opening the leading border of which is defined 
by a latch or cross bar and the trailing end of the tongue piece is 
provided with a belt securing slot. The frame 2 includes a base plate 14 
and opposing side plates that are directed upwardly from both longitudinal 
sides of the base plate 14. The front end portion of base plate 14 is 
partly raised and has a latch member defining and engaging projection 15 
which is medially located to releasably engage and latch the latch opening 
in the tongue piece 1 and which is located on a raised base surface 16 
which determines the angle at which the tongue piece is inserted. The 
projection 15 has a sharply upwardly forwardly inclined rear face and a 
slightly downwardly forwardly inclined upper front face. A long hole or 
slot 13 which is nearly parallel to the base surface 16 of the frame 2 is 
provided in each of the side plates 12 near the tip position of the 
leading end of the tongue piece 1 in its buckle inserted position beyond 
the engaging protrusion 15, and with said slots 13 is slideably engaged a 
transverse lock bar or elevation preventing pin 3 that prevents the 
elevating motion of the tongue piece 1. The side plates 12 of the frame 
have, as shown in the drawings, aligned pivot holes 18 which pivotally 
engage the rockable ears or plates 26 of the release or pressing member 4, 
spring hooking holes 20, and a recess 21 engaging the tips of a buckle 
cover. The side plates 12 also have at their front part notches 23 to 
increase the insertion angle of the tongue piece 1, define the insertion 
depth of the tongue piece 1 and prevent the upward movement of the tongue 
pice 1, as well as at their rear part notches 22 which engage the rear 
part of the buckle cover 5. On both sides of the base surface 16 are 
formed inwardly projecting fingers 19 and hairpin springs 7 which function 
to eject the tongue piece 1 are mounted as shown in FIGS. 1 and 2. The 
reference numeral 17 is a slot for connecting the buckle to the seat belt. 
The operation or release member 4 is swingably mounted to the frame 2 and 
plays an important role for the engagement and disengagement of the tongue 
piece. The upper surface of the operation member 4 serves as a pressing 
surface 24, and opposite side walls depend therefrom and have inclined cam 
holes or slots 25 which intersect and cooperate with the long holes 13 in 
the side plates 12 of the frame 2. At the lower external faces of member 4 
are provided the pivot plate 26 which project outwardly to superpose the 
side walls depending from top wall 24 of the operation member 4 on the 
inside faces of the side plates 12 of the frame 2 in a manner that the 
elevation preventing pin 3 is inserted through and in sliding engagement 
with the long holes 13 and the camholes 25. The pivot plates 26 are then 
fitted to the holes 18 to couple the operation member 4 to the frame 2. 
The reference numeral 27 is a pin provided and mounted on the inner 
surface at the front curved part of the operation member 4. To the pin 27 
is hooked one end of the spring 6. The other end of the spring 6 is hooked 
to the front part of the buckle cover 5 as hereinafter described. 
The buckle cover 5 is so formed as to contain the operation member 4 above 
the aforesaid frame 2, and has a window 30 through which is exposed the 
pressing surface or plate 24 of operation member 4 and further has 
recesses 31 that register with recesses 21 in frame 2 and a protrusion 32 
that engages the notches 22. The reference numeral 33 designates an 
opening formed at the tip of the buckle covering 5. 
The operation member 4 is fitted to the frame 2 and the elevation 
preventing pin 3 is inserted through the long holes 13 and the cam holes 
25 so as to fasten the pivot plates 26 to the pivot holes 18. The springs 
7 are then mounted on the projections 19 as a shaft, and then the tension 
spring 6 is connected between the operation member 4 and the buckle cover 
5 in order that the elevation preventing pin 3 is resiliently urged or 
biased to the front of the long holes 13 as seen in FIGS. 2 and 4. The 
protrusion 32 of the buckle cover 5 is then fitted to the notch of the 
frame 2 to complete assembly of the buckle of the present invention. 
To insert or remove the tongue piece 1 with respect to the buckle, the 
tongue piece 1 shown in FIG. 2 is brought near to the buckle front or 
insertion hole, and is then pushed beyond the engaging projection 15 to 
easily perform the fastening. At this time the motion at the tip of the 
tongue piece 1 is interrupted by the elevation preventing pin 3 which is 
positioned in front of the long hole 13 and the elevating motion of the 
tongue piece is thus prevented. Then to release the tongue piece, the 
pressing surface 24 is downwardly pressed, whereby the lock bar or 
elevation preventing pin 3 is moved along the cam hole 25 of the operation 
member 4, as shown in FIG. 5, and the pin 3 is moved from the front side 
toward the rear side in the long hole 13. The restraining action to the 
tongue piece 1 is released and the tongue piece 1 is easily released by 
the force of the spring 7. 
FIGS. 6 and 7 show another embodiment of the buckle of the present 
invention and except as described is similar to the one shown in FIGS. 1 
to 5. Although the pressing mechanism of the first embodiment included an 
upper pressing surface or plate at its upper part so that the tongue piece 
1 was liberated and disengaged when it was depressed, the mechanism in 
this embodiment is equipped with a release or slide pressure member 4' 
that moves horizontally in the back and forth directions. The slide 
pressure member 4' has on both of its walls an operation recess 29 that is 
provided with depending shoulders or fingers at its front and rear, in 
place of the cam holes. Both ends of the elevation preventing pin 3 
slideably engage the long holes 13, are positioned in the recesses 29 so 
as to be lost motion coupled with the slide member 4'. Further, at the 
upper central part is provided a spring bore 30 containing a pressure-type 
coil spring 6', the spring 6' being entrapped between the slide pressure 
member 4' and a spring abutment 34 of buckle cover 5'. 
In the embodiment shown, the buckle cover 5' is of the type to be inserted 
from the rear of the buckle, in which the base plate 14' is extended 
toward the rear and its rear end is fastened. 
In the above manner, the tongue piece 1 fastened to one side of the seat 
belt can be easily coupled or uncoupled with the buckle which is fastened 
to the other side of the seat belt with a flexible member 8' made of wire 
contained in the seat belt by way of rivet 9 at the connection hole 17', 
and connected to the fixed point of the belt. 
Such a connection may, of course, be done by stitching the belt, or by 
fastening it directly to the seat as shown in FIGS. 1 to 5, or a belt 
length adjusting means may be provided as required. 
Also, where the buckle cover 5' is made in the shape as shown and set up as 
mentioned above, the opening 33' on the side of insertion of the tongue 
piece 1 forms an insertion hole and provides a slide surface for the slide 
pressure member 4', whereby the guide plate 11 is engaged to the long hole 
or notch formed on the side plates of the frame 2, simultaneously 
interrupting the the elevating movement of the tongue piece 1. 
When the tongue piece 1 is to be inserted in the buckle shown in FIGS. 6 
and 7, the wall of the latch hole of the tongue piece 1 is introduced 
beyond the engaging protrusion 15 and engaged in the same manner as in the 
case of FIGS. 1 to 5, and at this moment, the engagement takes place with 
the tip of the tongue piece 1 being restricted by the elevation preventing 
pin 3. To release the tongue piece 1, the slide pressure member 4' is 
manually pressed so as to be moved in parallel and rearwards. The 
elevation preventing pin 3 positioned in the recess 29 is then pressed to 
the wall of the recess 29 and moved rearward releasing the tip of the 
tongue piece 1 from the restriction, whereby the tongue piece 1 is 
liberated from the buckle. 
Other mechanisms, operations and functions are the same as those of the 
first embodiment as illustrated in FIGS. 1 to 5. 
In this way, the buckle body of the present invention can be fastened to 
the seat belt to enable easy buckling and unbuckling operations of the 
belt. 
The buckle of the present device comprises the pressure operation member as 
mentioned above. And by simple operating the operation member, the 
elevation preventing pin is moved to liberate the tip of the tongue piece 
from the restriction, enabling it to disengage the tongue piece, i.e., to 
unbuckle the belt. Therefore, as compared to the earlier buckles of this 
kind, the number of required parts is reduced contributing to an increase 
in productivity and economy. Further, the buckle provides both features of 
push type and slide type using almost common parts, and is very economical 
having simple construction. Still more, since the elevation preventing pin 
is reliably moved, the fastening performance is also reliable and is very 
suited as a buckle for seat belts where safety is required. 
Moreover, the buckle of the present device is simple in mechanism and small 
in size, and is suited to be mounted in the restricted space of an 
automobile to fasten the seat belts, permitting easy insertion of the 
tongue piece and release of the tongue piece simple by depressing the 
pressing member, which are very simple and practical operations. 
While there have been described and illustrated preferred embodiments of 
the present invention, it is apparent that numerous alterations, omissions 
and additions may be made without departing from the spirit thereof.