Device for stopping the flow of blood in extremities

A device for ligaturing parts of the body comprises a flat strap (15) of elastic material in the form of a loop (35) and a buckle attached to the latter comprising a clamping part (1) and a releasing part (2). The clamping part comprises a basic element (29) which forms a basic supporting and guiding surface (39) in the longitudinal direction of the strap (15) and has lateral faces between which the strap passes and which have locking elements ensuring a releasable connection between the clamping part (1) and the releasing party (2). The latter is connected to one end (22) of the strap, has locking elements which releasably connect it to the clamping part (1) and a clamping region (3) at the end opposite the loop (35) whose distance from the surface (39) is located in the region of the thickness of the released strap (15) when the strap buckle is assembled. When the strap buckle is assembled, the locking elements form a pivoting joint. When pressure is exerted on a front external face (18) of the releasing part (2) located between the locking elements and the buckle (35), the clamping part (3) moves away from the basic surface (39), thereby releasing the device. On the end of the clamping part (1) facing the buckle (35), a transverse rib (12) projects from the basic surface (39) towards the releasing part (2), by a distance equal to the thickness, preferably twice the thickness, of the strap. As it passes over the transverse rib, the strap (15) changes direction.

The invention pertains to a device for stopping the flow of blood in 
extremities as described in the characterizing part of claim 1. 
In this device, which is already known from DE-OS 35 38 583, the base runs 
flat as far as the forward edge of the clamping device, i.e., the edge 
facing the loop. The part of the strap that forms the loop is bent at the 
forwardmost edge of the base, forcing the strap to follow a path along the 
base. The strap is clamped farther back on the base in the clamping zone. 
When the device is used, the loop is placed around an extremity, for 
example, an arm, and the end of the strap is pulled through the clamping 
device until the loop surrounds the arm tightly enough. When this is done, 
the loop becomes smaller, a segment of the strap is pulled into the 
clamping device over the above-described forward edge, and the end of the 
strap extending beyond the clamping device becomes longer. However, when 
the loop is tightened and the strap enters the clamping device, the skin 
in contact with the inner surface of the strap is pulled along with the 
loop and forms a fold. As the loop is drawn further into the strap clamp, 
the fold of skin is clamped tighter and tighter, causing pain. 
The objective of the invention was to improve the device of the type 
described above in such a way that skin cannot be drawn into the strap 
clamp so far as to cause pain. 
This objective is accomplished by the device specified in patent claim 1. 
The transverse rib initially raises the strap higher than is necessary for 
the strap to run into the base. It then runs down to the base and, at 
least in the clamping region, rests against the base. Therefore, the strap 
is bent at a greater angle than in state-of-the art devices of this type. 
As a result, the skin that is drawn in by friction is behind the 
transverse rib and thus no longer rests against the strap inside the strap 
clamping device. The transverse rib produces separation between the strap 
and the skin that is drawn in frictionally by the strap. This could also 
be described as a type of separation edge. This eliminates tight squeezing 
of the skin and prevents pain. The skin is still drawn in by the strap, 
but it is no longer pulled into a constriction transverse to the strap, 
where pinching or clamping could occur. 
In another design, the transverse rib has an inclined surface for 
supporting the strap. The inclined surface basically follows the direction 
of the entering segment of the loop. In this way, the bending of the strap 
does not occur directly at the front face but rather a few millimeters 
behind it, e.g., three to five millimeters. 
In another design improvement, the inclined surface is inclined at an angle 
of 30.degree. to 60.degree. to the base and preferably at an angle of 
45.degree.. This produces the desired, relatively large bending angle of 
the strap. The inclined surface defines the angle of entry of the strap; 
behind the inclined surface and the transverse rib, the strap is bent back 
towards the base in the opposite direction. In this way, there is a total 
bend of at least 50.degree. (with respect to the unbent direction). 
In another design improvement, the upper edge of the transverse rib is 
displaced relative to a frontal face of the clamping device that faces the 
loop, and it is preferably displaced by at least the width of the strap. 
This also causes the strap to bend inside the strap clamping device.

The drawings in FIGS. 1 to 5 show the device in its tightened working 
position. 
The device consists of a strap 15 that forms a loop 35 with a portion of 
its total length, the clamping part 1 and the release part 2. Clamping 
part 1 and release part 2 are geometrically equal parts (congruent parts) 
and can be fastened together by lengthwise movement (in the longitudinal 
direction of the strap 15) and released in the opposite direction. A 
bridge-like structure is mounted on a basically rectangular foundation 29. 
This bridge-like structure consists of two congruent side walls 14 and a 
bridge part 7 connecting them. The latter part has a beveled, roof-like 
projecting part 10. In the extended state of the strap 15, i.e., with the 
loop 35 released, the release part 2 is located at one end of the strap, 
and the clamping part 1 is located along the length of the strap. In this 
position of the device, the two parts 1 and 2 are displaced with respect 
to each other in the longitudinal direction of the strap 15. To form the 
loop 35 starting from this position, one part is moved 180.degree. around 
an axis lying transverse to the plane of the strap, leading to the 
arrangement of parts 1 and 2 that is shown in FIG. 1 to 4 and FIG. 6, in 
which the roof-like projection 30 the release part 2 hooks under the 
roof-like projection 10 of clamping part 1, acting as locking mechanisms, 
locking clamping part 1 and release part 2 together and at the same time a 
pivot joint is formed at this point. 
If there is no tension in the loop 35, i.e., if the strap clamping device 
is not in its tightened working position, the clear opening 31 of the 
clamping zone 3 is just large enough to allow the strap 15 to be moved in 
the longitudinal direction. However, as shown in FIGS. 2 and 6, as soon as 
a tensile stress exists in the loop 35 and as a result the front ends of 
the two parts 1 and 2 that face the loop 35 are moved away from each 
other, the tightened working position shown in the drawings is attained. 
This reduces the clear opening 31, causing the strap 15 to be clamped in 
clamping zone 3. The strap 15 passes through a chamber 11 in the clamping 
part 1. The thickness of the loose end of the strap 32 is increased by 
folding over and clamping (clamp 33) the strap material (overlapping 27) 
to prevent the strap from being pulled out inadvertently. 
The strap's other end 22, which is permanently attached to the release part 
2, is undetachably connected by wrapping it around crossbar 24 and 
clamping the overlapped portion 25 of the strap with a longitudinally 
placed clamp 26. The strap material is both longitudinally and 
transversely elastic. 
The loop 35 formed by strap 15 is placed around the extremity to be 
compressed. The release part 2 is hooked together with the clamping part 1 
by moving it longitudinally. The strap 15 is tightened by pulling the free 
end 32 of the strap. This presses the clamping part 1 against the strap in 
the clamping zone 3. The resulting strap tension Z increases along the 
circumference of loop 35 from the permanent attachment loop 34 at the 
release part 2 towards the clamping part 1 (Z1, Z2, Z3), so that the strap 
15 is secured by clamping in clamping zone 3 with the long lever arm 5 of 
the clamping part 1 and the common fulcrum 4 to prevent its movement in 
the longitudinal direction. 
Compression of the limb is also achieved in the strap entry region of the 
device by the projecting surfaces 17. 
The strap tensile force "Z" decreases along the circumference of the limb, 
so that only residual tensile force "Z1" opposes the release of release 
part 2. 
When outer surface 18 of release part 2 is lifted, the release lever length 
36 exerts a large leverage on the forward release part 2 in the downward 
direction towards the clamping part 1 to terminate the clamping effect in 
clamping zone 3 and allows gentle release of the compression. The process 
of gentle release of compression is enhanced by a deflection of the strap 
on a transverse rib 12 at the front face and by the resulting strap 
friction. 
After the strap tensile force is removed, by lightly pulling the roof-like 
projection 10 of the release part 2 back from the chamber 11 of the 
clamping part 1, the release part 2 is easily separated. 
In the released state of the device, the surface 18 of the release part 2 
and the surface 19 of the clamping part 1 form a wedge inclined towards 
the strap loop 35 to make it easier to manipulate the device during 
removal of compression, release and separation. The increased thickness 27 
of the strap material in clamping zone 3 in the released state of the 
device pushes the parts into the advantageous position described above. 
A transverse rib 12 extending the entire width of the strap and running at 
right angles to the strap is located at the forward end of the foundation 
29. The transverse rib 12 can be designed in any desired way. In the 
specific example shown in the drawings, the transverse rib 12 is a 
one-piece component of the clamping part 1, which itself otherwise 
consists of a single piece. However, it can also be an inserted, possibly 
rotatable axis, a number of projections arranged side by side transverse 
to the strap direction, or a similar design. The only critical feature is 
that the strap must pass over an edge, which in the example shown in the 
drawings is the highest elevation of the transverse rib 12. The upper, 
inner side of the foundation forms a base 39 that extends practically the 
entire length of the foundation. The transverse rib 12 projects several 
milimeters, for example, 2 to 3 milimeters, from this base 39. Expressed 
in slightly different terms, it projects from the base 39 at least the 
thickness of the strap and in a preferred design of the invention at least 
twice the thickness of the strap (i.e., 4 to 6 mm). Towards the front 
surface 17 the transverse rib 12 is bounded by an inclined surface 13 
which is inclined at an angle of 45.degree. to the base 39. The upper edge 
of the transverse rib is thus not in the immediate vicinity of the front 
surface (which should not be expressly excluded), but rather is displaced 
inwardly (by about 5 mm in the example shown in the drawings). The 
inclined surface 13 becomes a rounded edge 43 towards the forward outer 
surface 19 of the clamping part 1. This rounded edge is located slightly 
(only a few tenths of a millimeter) behind the front face 17. On the side 
of the strap 15 turned away from the clamping part 1, a free space towards 
the release part 2 or towards the end 22 of the strap is left between the 
front surface 17 and the upper edge of the transverse rib 12. This free 
space is wider than the single width of the strap. Specifically, it does 
not taper like a funnel, but rather widens out behind the upper edge and 
as far as the beginning of the bridgelike structure 7 of the clamping part 
1, so that skin cannot be pulled in in a funnel-like fashion in this area. 
Between the transverse rib 12 and the bridge part 7 of the clamping part 1 
there is a slot for the passage of the strap. Behind this slot the strap 
passes through a chamber 11 and comes to a position below the clamping 
zone 3, where it is clamped. This is the first point at which the strap 
comes into contact with the base 39. 
An edge of the bridge part, which extends over the entire width of the 
strap, rests against the surface of the strap that forms the inner surface 
of the loop. As FIG. 2 shows, this edge is positioned in such a way with 
respect to the transverse rib 12 that the strap is bent very slightly in 
the opposite direction from the direction in which the strap is bent by 
the transverse rib. This gives the strap a slightly S-shaped course. 
However, the bend at the edge of the bridge part 7 is much smaller, for 
example, less than 10.degree., while the bend at the transverse rib is at 
least five times and preferably ten times greater.