A carabiner having a body which forms a part of a loop. A gate is connected to the body and forms a closed loop configuration therewith when the gate is in the closed position. A trigger is provided to release the gate from an open position. The trigger operates at the pivot end of the gate, preferably working in conjunction with a biasing spring. The preferred biasing spring holds the gate in an open position until the gate is activated to release. The biasing spring also preferably forces the gate into the closed position.

FIELD OF THE INVENTION 
This invention relates to carabiners that are used in combination with 
ropes by mountaineers or climbers to ensure safety. 
DESCRIPTION OF THE PRIOR ART 
For safety in case of a fall, climbers attach a rope to themselves and have 
a partner who is secure in position to hold the rope. Often the climber is 
above the person holding the rope. Therefore, the climber has to attach 
the rope to the mountain so that the rope is free to move with the 
climber, but the rope must hold the climber through the action of the 
partner in case of a fall. The device that is used to make the connection 
between the rope and another element that is attached directly to the 
mountain is a carabiner. A carabiner is a closed loop having a gate which 
can be opened or closed to allow entry of a rope or other connection 
member. Most typically, a carabiner is formed as a C-shaped element with a 
gate bridging the opening to make the closed connector. 
Because of the time required to attach some element directly to the 
mountain and then make the connection to the rope with a carabiner the 
climber has to be in a secure position. When climbers do harder routes the 
positions of the climbers are less secure, and attaching their rope to the 
mountain needs to be as efficient as possible. In some cases, the element 
that is attached directly to the mountain and the accompanying carabiner 
are in place before the climber climbs, and it is left for the climber to 
simply attach the rope to the carabiner. 
In an effort to make the process of attaching the rope to the carabiner as 
easy as possible, Fister and Grosset describe a self-closing carabiner in 
U.S. Pat. No. 5,005,266 (9 Apr. 1991). Although the invention is 
self-closing, it does suffer from at least two serious disadvantages: 
(a) The gate of the carabiner is propped open by a tongue. Aligning the end 
of the tongue with the end of the gate during a climb is difficult. 
Therefore, the usefulness of Fister's carabiner is limited to applications 
where it can be prepared for use by propping the gate open before the 
climb. 
(b) The tongue mechanism of the Fister and Grosset carabiner is located in 
the part of the carabiner that must take high pressure contact with the 
rope in the event that the climber falls. Therefore, the tongue is likely 
to get damaged. Even worse, a damaged tongue might damage the rope. 
A solution to the above problem (a) is described by Isenhart in U.S. Pat. 
No. 4,802,264 (7 Feb. 1989). Isenhart describes a gate that includes an 
over-center linkage to bias the gate toward either the open or closed 
position (away from the half-open position). The problem with this 
invention is that it is not self-closing. 
OBJECTS AND ADVANTAGES OF THE INVENTION 
Accordingly, several objects and advantages of the present invention are as 
follows: 
(a) to provide a self-closing carabiner that is easy to use during a climb; 
(b) to provide a self-closing carabiner that is not prone to damage; 
(c) to provide a self-closing carabiner that has no increased risk of 
damaging the rope. 
Still further objects and advantages will become apparent from a 
consideration of the ensuing description and drawings.

DESCRIPTION OF THE INVENTION 
Two embodiments of the carabiner of the present invention are illustrated 
in FIG. 1. A carabiner (1a) is shown connected by a strap (2) to a 
carabiner (1b) as is often the case in actual use. Because carabiner (1a) 
is connected to an anchor (3) in the rock and is not used with a rope, it 
is not necessary that carabiner (1a) have the self-closing feature of the 
present invention. For illustrative purposes, however, carabiner (1a) is 
shown as an embodiment of the present invention. Carabiner (1b) differs 
from carabiner (1a) in the addition of a web (4) that strengthens the 
carabiner and forms a strap aperture (5). Carabiner (1b) is shown prepared 
for the entrance of a rope (6). 
Embodiment of FIG. 2. 
Carabiner (1b) is illustrated in more detail in FIG. 2. The carabiner 
includes a body (7) that is generally C-shaped with a strap section (25) 
that is approximately cylindrical and shifted distally in a continuous and 
smooth manner from the remainder of body (7). Body (7) also includes web 
(4) joining the parts of the body on each side of strap section (25). Web 
(4) in combination with strap section (25) form strap aperture (5) for 
strap (2). See FIG. 1 for strap (2). The opening of the carabiner is 
bridged by a gate (8) that is illustrated in the open position. Gate (8) 
has a pivot end adjacent to a gate pivot (9). The gate rotates about gate 
pivot (9) so that when the gate is closed a pin (10) which is mounted or 
formed at the distal end of the gate, rests in a notch (11). Gate (8) is 
biased toward the open or closed position (away from a three-fourths-open 
position) by an over-center linkage. 
The over-center linkage comprises a biasing spring (12) made from flat 
wire, having a spring section (13) and a linear end section (14), that 
works in combination with gate (8) and body (7). Biasing spring (12) is 
confined within an axial bore (15) in body (7) as shown in section view. 
Linear end section (14) of biasing spring (12) is further located by a 
groove (16) in gate (8). 
A trigger (17) is an L-shaped flat-wire element with a lever section (18) 
and a pushing section (19) joined by an elbow (20). Lever section (18) 
extends adjacent to strap section (25) of body (7), between strap (2) and 
strap section (25), and through a transverse bore (21) to axial bore (15). 
See FIG. 1 for strap (2). Pushing section (19) extends in axial bore (15) 
adjacent and distal to biasing spring (12) nearly to the end of linear end 
section (14) but not interfering with gate (8). Trigger (17) is stiff 
except for a resilient section (22) located in the center region of lever 
section (18). Trigger (17) is held in position by axial bore (15) and by a 
saddle (23) that conforms to the locally cylindrical cross-section of body 
(7). Trigger (17) is additionally positioned by the force from spring 
section (13) of biasing spring (12). 
Embodiment of FIG. 3. 
Another embodiment is shown in FIG. 3. It is different in that biasing 
spring (12) of the embodiment shown in FIG. 2 has been eliminated and 
replaced by two parts, a compression coil spring (26) and a shank (27). 
Preferred embodiment shown in FIG. 4 to FIG. 9. 
The preferred embodiment of the present invention is illustrated in FIG. 4 
to FIG. 9. The carabiner includes a body (30) that is generally C-shaped 
with a strap section (31) that is shifted distally in a continuous and 
smooth manner from the remainder of body (30). Body (30) has a slot (32) 
parallel and medial to a left hinge section (33a) and a right hinge 
section (33b). A left web (34a) joins left hinge section (33a) with body 
(30) on the other side of strap section (31). A tight web (34b) joins 
right hinge section (33b) with body (30) on the other side of strap 
section (31). Left web (34a), fight web (34b), and strap section (31) form 
a strap aperture (35) for a strap (36). Left web (34a) and right web (34b) 
are joined together and stiffened by a gusset (46). The opening of the 
carabiner is bridged by a gate (37). Gate (37) rotates about a gate pivot 
(38) so that when the gate is closed a flange (39) rests in a cleft (40). 
This gate engagement construction at the distal end thereof and the mating 
part of the body, provides resistance against lateral forces which are 
applied to the gate relative to the body. See FIG. 8 and FIG. 9. Gate (37) 
is biased toward the open or closed position (away from a 
three-fourths-open position) by an over-center linkage. 
The over-center linkage comprises a trigger (41) made from flat wire, 
having a biasing section (42) and a lever section (43), that works in 
combination with a groove (44) in gate (37) and a trigger pivot (45). 
Biasing section (42) has a serpentine shape between groove (44) and 
trigger pivot (45). Lever section (43) extends along the medial border of 
strap section (31) in strap aperture (35), between strap section (31) and 
a strap protector (46). Where biasing section (42) and lever section (43) 
join is a half-circle shape that rests against trigger pivot (45). The 
force of biasing section (42) between groove (44) and trigger pivot (45) 
holds trigger (41) in place. Strap (36) is protected from lever section 
(43) by strap protector (46). 
Embodiment of FIG. 10. 
Another embodiment is shown in FIG. 10. It is similar to the preferred 
embodiment shown in FIG. 4 to FIG. 9. The primary difference is that a 
manual activation section (43a) is provided with exposed surfaces which 
can be used to manually displace the trigger. This can be used instead of 
the lever section (43) of trigger (41 ) which is alternatively activated 
by applying a load using a connecting strap or other connecting member 
(not shown in FIG. 10). 
OPERATION OF THE INVENTION 
Embodiment of FIG. 2. 
Gate (8) is pushed open by the user against the force of biasing spring 
(12). As gate (8) crosses over the approximately three-quarters-open 
position, groove (16) will cross over the center-line between gate pivot 
(9) and biasing spring (12), and the gate will be forced to the open 
position by biasing spring (12). It is now a simple matter for the climber 
to place the rope in the carabiner. To close the carabiner the climber 
simply pulls down on the rope. The act of pulling down on the rope or 
carabiner against the force from strap (2) will force lever section (18) 
of trigger (17) toward strap section (25) of body (7), as shown by an 
arrow (24). Lever section (18) will bend in resilient section (22). This 
will cause pushing section (19) of trigger (17) to rotate clockwise about 
elbow (20) and push linear end section (14) of biasing spring (12) to the 
left. Since linear end section (14) of biasing spring (12) is located in 
groove (16), gate (8) will be forced to rotate counterclockwise against 
the force of biasing spring (12). But as groove (16) crosses over the 
center-line between gate pivot (9) and biasing spring (12), gate (8) will 
be forced to the closed position by the biasing spring. It is clear that 
the user could manually move gate (8) toward the closed position, if for 
some reason pulling down on the carabiner was undesirable. 
Embodiment of FIG. 3. 
This embodiment operates the same as the embodiment of FIG. 2. The only 
difference is that compression coil spring (26) and shank (27) do the work 
that was done by biasing spring (12) in the embodiment of FIG. 2. 
Preferred embodiment shown in FIG. 4 to FIG. 9. 
Gate (37) is pushed open by the user against the force of biasing section 
(42) of trigger (41). As gate (37) crosses over the approximately 
three-quarters-open position, groove (44) will cross over the center-line 
between trigger pivot (45) and gate pivot (38), and the gate will be 
forced to the open position by biasing section (42). It is now a simple 
matter for the climber to place the rope in the carabiner. To close the 
carabiner, the climber simply pulls down on the carabiner. The act of 
pulling down on the carabiner against the force from strap (36) will force 
lever section (43) toward strap section (31). This will cause trigger (41) 
to rotate counterclockwise about trigger pivot (45) and push biasing 
section (42) to the right. Since the end of biasing section (42) is 
located in groove (44), gate (37) will be forced to rotate clockwise 
against the force of biasing section (42). But as groove (44) crosses over 
the center-line between trigger pivot (45) and gate pivot (38), gate (37) 
will be forced to the closed position by biasing section (42). It is clear 
that the user could manually move gate (37) toward the closed position, if 
for some reason pulling down on the carabiner was undesirable. 
Alternate design of the preferred embodiment of FIG. 4 to FIG. 9. 
It is also possible that the center of the over-center mechanism be 
designed to occur at the full open position of gate (37). That is, when 
gate (37) is in the full open position, groove (44) will be on the 
center-line between trigger pivot (45) and gate pivot (38). In this case, 
gate (37) is not biased to the open position but instead is held there by 
the friction caused by the force from biasing section (42) of trigger (41 
). It is now a simple matter for the climber to place the rope in the 
carabiner. To close the carabiner, the climber simply pulls down on the 
carabiner. The act of pulling down on the carabiner against the force from 
strap (36) will force lever section (43) toward strap section (31). This 
will cause trigger (41) to rotate counterclockwise about trigger pivot 
(45) and push biasing section (42) to the right. Since the end of biasing 
section (42) is located in groove (44), gate (37) will be forced to rotate 
clockwise against the frictional forces caused by trigger (41). But as 
groove (44) moves substantially away from the center-line between trigger 
pivot (45) and gate pivot (38), gate (37) will be forced to the closed 
position by biasing section (42). 
Embodiment of FIG. 10. 
This embodiment operates similar to the preferred embodiment of FIG. 4 to 
FIG. 9. The primary difference is that the manual activation section (43a) 
is provided with exposed surfaces which can be manually displaced to 
activate the trigger. This can be used instead of the lever section (43) 
of trigger (41) which is alternatively capable of activation by applying a 
load using a connecting strap or other connecting member (not shown in 
FIG. 10). 
SUMMARY, RAMIFICATIONS, AND SCOPE 
Accordingly, the reader will see that this invention provides for a 
self-closing carabiner that is easy to use. It is not necessary for the 
climber to align a prop to hold the gate open. The climber simply opens 
the gate past the three-quarter-open position, and the gate is held open. 
Closing the carabiner is a simple matter of activating a trigger. 
Furthermore, the trigger is in a protected place so that it is not prone 
to damage. And even more important, the trigger cannot damage the rope. 
While my above description contains many specificities, these should not be 
construed as limitations on the scope of the invention, but rather as an 
exemplification of embodiments thereof. Other variations are possible. 
Also, this invention is not limited to use in climbing or mountaineering 
but may have application in other fields such as rescue operations. 
Accordingly, the scope of this invention should be determined not by the 
embodiments illustrated but by the appended claims and their legal 
equivalents.