Lead line between at least two persons, particularly for cross country skiing or ski touring

A lead line between at least two persons who are moving in a line, particularly on skis, in order to facilitate the movement of the person or persons at the rear; this device includes at least two harnesses, each adapted to be worn by one of the persons, and at least one towline which is made up of an elastic section and safety coupling adapted to be released when a predetermined tension on the towline is exceeded; each towline connects two consecutive harnesses by attachment inclined in the harnesses.

This invention relates to a lead line between at least two persons who are 
moving in a line, particularly on skis, in order to facilitate the 
movement of the person or persons situated at the rear. 
BACKGROUND AND OBJECTS OF THE INVENTION 
Forms of sport consisting of individual gliding movement (cross country 
skiing or ski touring, long distance ice skating . . . ) or rolling 
movement (roller skating . . . ) are increasingly popular today with the 
public, where they are considered both as relaxation and as means of 
maintaining the physical condition. The possibility of practicing these 
disciplines outside, particularly in family groups, increases their 
popularity. Thus, cross country skiing or ski touring, for example, have 
become exceptionally more widespread in the last few years. 
But, as in all sports, different levels of expertise exist in the practice 
of these disciplines: the distance covered and the speed of movement are 
different according to the training and the physical capacities of each 
person. Particularly within one family, the father, the mother and the 
children are generally each at a different level: when these disciplines 
are practiced in a group, they pose numerous problems and the relaxation 
is quickly transformed into wearisome exercise, perhaps even dangerous, 
for certain members of the group. In fact, in a group of persons of 
different levels of expertise, each must adapt a rate of movement to 
preserve the togetherness of the group: those who are adept in the 
discipline must reduce their normal speed and thus lose the benefit of the 
sport by waiting (reduced distance at reduced speed), while the persons or 
children who are less trained and less strong must move at speed beyond 
their physical capacities and thus are exposed to the resulting risks 
(shortness of breath, muscular fatigue and particularly stress on the 
heart). 
The present invention discloses a lead line between at least two persons 
who are moving in file, particularly on skis, in order to facilitate the 
movement of the person or persons situated at the rear, it being 
understood that the persons situated at the front of the group are at a 
superior level in the practice of the particular discipline to those 
situated down the file. 
The main object of this device is to equalize a group participating in one 
of the aforementioned disciplines and comprised of persons of different 
levels, so as to permit the group on the one hand to adopt a rate of 
movement which is acceptable to all and on the other hand to cover a 
satisfactory distance for all. This device consequently permits agreeable 
group or family practice of the disciplines such as cross country skiing 
or ski touring. 
SUMMARY OF THE INVENTION 
To accomplish these objects, the device according to the invention includes 
at least two harnesses, each adapted to be worn by one person, and at 
least one towline connecting two consecutive harnesses. This device 
permits the lead persons, who are adept in the practice of the discipline, 
to transmit the traction forces to the persons situated to the rear, of 
lower level of expertise, by means of the towline. There is a distribution 
of effort within the group and therefore equalization of the group. The 
harnesses serve to distribute the forces delivered or received by the 
harness wearer over adequate zones of the body. 
According to one characteristic of the invention, each towline between two 
harnesses is affixed immovably to the front of the rear harness in the 
line and to the rear of the front harness in the line by attachment means 
which are adapted to permit attachment to and rapid release from said 
towline. 
According to a preferred embodiment, each harness includes a system of 
straps including two principal straps forming suspenders and an abdominal 
or thoracic belt. This system of straps distributes the forces of traction 
which are received in the back, at the level of the shoulders. It can also 
include at least one rear auxiliary strap carrying attachment means for 
the rear towline, particularly mounted to slide along this strap. 
Besides, each harness preferably includes regulation means to permit 
adaptation or adjustment to the body of the person wearing it. 
According to another characteristic of the invention, each towline 
connecting two consecutive harnesses is at least partially elastic. When 
the towline transmits the traction force, a role of shock absorber is 
added also, which avoids disturbance of the equilibrium of the person who 
receives or develops the force of traction, when the force is too jerky. 
To avoid the towline being subjected to too great elongation, it can 
advantageously be comprised of a short elastic section between two 
nonelastic sections of greater length. According to another characteristic 
of the invention, each towline is provided with a safety coupling which 
permits release of the two concerned persons when the traction on the 
towline becomes greater than a predetermined value. This safety coupling 
can be arranged between two separate portions of each towline to detach 
them when a predetermined tension is exceeded. 
Thus, if the person being towed falls, that person is released, which 
considerably reduces the risk of injury by preventing this person from 
being drawn along the ground after falling. Moreover, the risks of falling 
to the person towing or to other persons of the group is eliminated. 
The safety coupling comprises preferably a male element provided with a 
head of larger diameter preceded by an inclined portion, and a female 
element connected therewith provided on the inside with at least one 
catch. This catch is of a form to fit the inclined portion of the male 
element and latches with the head of the male element. When a 
predetermined tension is applied on the two elements the radial elasticity 
of the catch allows it to be radially displaced and to uncouple the two 
elements, releasing the head of the male element. Thus, the section of the 
towline which is integral with one element and the section which is 
integral with the other element are connected until a predetermined 
tension is reached and are separated when this tension is attained. After 
separation, the two sections are reconnected manually. 
The radial elasticity of a catch can be assured by that of a blade or 
furcation on which it is affixed. These blades longitudinally constitute a 
part of the body of the female element. The adjustment means increases or 
decreases the free length of each blade so as to increase or decrease the 
radial elasticity. The release tension is determined according to the 
weight of the person being towed and the friction coefficient on the 
displacement surface of the moving element being used (for example skis).

DESCRIPTION OF THE INVENTION 
The embodiment shown in FIG. 1 includes two harnesses 1 and 2 connected by 
a towline 3 on the order of approximately 2.80 m length. 
The towline 3 is composed of a front cord 4 affixed to the rear of harness 
1 and on the order of 1.50 m in length, a short elastic cable 5 on the 
order of 0.50 m in length, a small nonelastic cord 6 of greater length 
than that of cable 5 and which backs up cable 5, and finally a rear cord 7 
with two strands of a V-shape, of which the two ends are suitably affixed 
to the front of harness 2. The cord 7 has a length such that the harness 
is found at approximately 0.80 m to the rear of the end of elastic cable 
5. 
Cord 4 is connected to harness 1 by means of a snap device 8 which can 
slide along a rear strap 9 of the harness as seen in FIG. 1a. 
Cord 4 and elastic cable 5 as well as small nonelastic cord 6 which backs 
up cable 5 are connected together to loops 10 by means of traditional 
eyelets as seen in FIG. 1c. 
This elastic cable 5 and small cord 6 are connected to cord 7 by a safety 
coupling 11 which will be described hereinafter. 
To avoid the small cord 6 hanging out too far, it can be connected to cable 
5 at one or more intermediate points, by means of one or more small rings, 
as shown in FIG. 1. V-shaped cord 7 is connected to the front of harness 2 
by two rings 12 on the harness, by means of a snap device 13 as seen in 
FIG. 1c. 
Harnesses 1 and 2 in FIG. 1 are identical, except that the first is 
provided with an immovable backpack 14 of flexible material which is 
affixed on it by four snaps 15 shown on harness 2. 
Each harness 1 or 2 is composed of two principal straps 16 and 17 forming 
suspenders, an abdominal belt 18, the aforementioned rear strap 9 and two 
auxiliary straps 19 and 20, respectively connecting the front and rear 
tops of suspenders 16 and 17. These two suspenders 16 and 17 are crossed 
at the rear and are connected at the front and at the rear to abdominal 
belt 18. 
Rear strap 9 is affixed at the top to strap 20, and at the bottom onto 
abdominal belt 18, and is of sufficient length to permit mounting of 
backpack 14. 
The abdominal belt has a front buckle 21 for securing the harness. It is to 
be noted that the suspenders can also be provided with buckles which 
permit regulation of the length. Rings 12, by means of which the traction 
is carried out, are affixed at the top of suspenders 16 and 17 such that 
once the harness is in place, they are found to be nearly in the middle of 
the chest of the harness wearer. 
Padding can be provided on the suspenders if desired to soften their 
contact with the shoulders of the wearer. 
Abdominal belt 18 can include a part which has a certain adherence with the 
clothing of the harness wearer, in order to dismiss any risk of the 
harness riding up on the chest of the wearer. 
Backpack 14 is provided with a side pocket where towline 3 can be stored 
when not in use. 
Other embodiments of the harness are shown in FIGS. 2, 3 and 4. 
FIG. 2 shows a harness 22 with a rigid framework on the rear, to which are 
attached the suspenders 23 and abdominal belt 24. This rigid framework is 
comprised in the example of two essentially vertical shafts 25 and 26 with 
shafts 27 and 28 between them and slightly arched toward the outside. 
Suspenders 23 and belt 24 are affixed on each side on vertical shafts 25 
and 26. 
Shaft 28 has a ring 29 which permits attachment of the towline by means of 
a snap element, while attachment loops 30 and 31 are provided on shafts 
27, 25 and Z6 to hold a backpack by means of hooks which are provided 
thereon. FIG. 3 shows a backpack 31 attached to the harness. 
The examples of FIGS. 2 and 3 show a screen of flexible material provided 
on the front of the rigid framework in such a manner as to be applied 
against the back of the wearer of the harness and to make its carriage 
more comfortable. 
FIG. 4 shows a harness 33 which is shorter and has a small flexible 
backpack incorporated with it. This harness is provided with suspenders 35 
and 36 sewn at the bottom onto a thoracic belt 37 which surrounds the 
thorax of the wearer. 
To the rear, suspenders 35 and 36 join and are extended by a strap 38 which 
permits attachment of the towline. This strap 38 is sewn at the bottom 
onto thoracic belt 37. 
Backpack 34 is sewn onto suspenders 35 and 36 and the rear of thoracic belt 
37; it is placed at the top of the back when the harness is in place. 
The safety coupling 11 which is found between elastic cable 5 and cord 7 
comprises, as shown in FIGS. 5 and 6, a female element 39 and a male 
element 40, preferably of molded plastic material. Male element 40 is 
composed of head 40a attached to the body by an inclined portion P. Female 
element 39 is a threaded cylinder constituted of four flexible blades 39a 
of rounded form. Each blade 39a includes a catch 41 of form to fit the 
inclined portion P of the male element. A ring 42 is screwed on the 
cylinder and thereby increases or decreases the effective length of lamina 
39a. Because of this, it increases or decreases the radial elasticity of 
each catch 41. Male element 40 is affixed on V-shaped cord 7. Elastic 
cable 5 and small cord 6 are threaded on the inside of female element 39 
and are each retained by a tightened ring 43. 
A calibration can be provided along element 39 to indicate the 
disengagement force of male element 40 as a function of the degree to 
which ring 42 is screwed. The user thus has the possibility of rapid 
regulation of the release threshold as a function of the weight of the 
person being towed. For a child approximately 17 kg, for example, this 
release threshold will be adjusted to be activated from the tension point 
on the order of 2 kg; for an adult of approximately 50 kg being towed, 
this threshold of release can be adjusted to about 5 kg. 
The use of the device of the invention is illustrated in FIG. 7 where a 
family is shown including father, mother, and daughter in the course of a 
ski tour. The father in this case has the best physical condition and 
training, and is situated at the head and wearing a harness of the type 
described which in the example is provided with a backpack. The woman in 
second position is wearing a harness without backpack; she is aided in her 
progress by the traction transmitted by the towline. A part of the force 
of traction which she receives is transmitted to the daughter who also is 
wearing a harness, adapted to her size. 
Experiments have established unexpectedly that the force of traction 
necessary to equalize a group of very different levels is in fact very low 
and causes only negligible fatigue for the persons in the front. 
For example, a dynamometer placed on the towlines in the two following 
situations furnished the indications below: 
passive tension on flat terrain (absence of movement on the part of the 
woman and the child) equal to 500 gr mean for a woman of 50 kg and a child 
of 17 kg. 
active traction for the skiers (same weight as preceding, towed at a faster 
rate than their natural rate) on the order of 100 to 200 gr. 
A child who is thus aided can cover a distance on the order of triple that 
which she would cover alone, at a rate equal to that of an adult. 
It is to be noted that small cord 6 which backs up the elastic cable of 
each towline 3 limits the extension of this cable and deletes risks of 
cable break, because beyond a very slight extension far below the limit of 
elasticity of this cable, this small cord is found in taut state and 
supports extra tensional forces; besides, its presence and the structure 
of the towline (with a short elastic section between two nonelastic 
sections) eliminates any possibility of one of the elements of coupling 11 
returning toward one of the skiers in case of its release: male element 40 
which remains attached to nonelastic cord 7 falls in place, and female 
element 39 which remains attached to elastic cable 5 and to small cord 6 
is subjected to too small a force to be able to cover the entire length of 
section 4 and thus cannot, in any case, reach the back of the front skier. 
Another application of the device for slope skiing consists of pulling a 
child while riding a ski-lift. In general, the bias of the springs 
suspending the bars of the ski-lifts do not allow children to use such 
devices; in fact, children, because they are too light, cannot remain in 
contact with the snow. 
While this invention has been described as having a preferred design, it 
will be understood that it is capable of further modification. This 
application, is therefore, intended to cover any variations, uses, or 
adaptations of the invention following the general principles thereof and 
including such departures from the present disclosure as come within known 
or customary practice in the art to which this invention pertains, and as 
may be applied to the essential features hereinbefore set forth and fall 
within the scope of this invention or the limits of the claims.