Apparatus for practicing skiing

An exercising apparatus for use by skiers to practice downhill runs, slalom runs and analogous types of runs has a main frame supporting a swaying frame which is turnable with reference to the main frame about two parallel horizontal axes extending longitudinally of the main frame. The movements of the swaying frame to either side of a central longitudinal vertical symmetry plane are opposed by strong coil springs whose bias is adjustable by a feed screw. The swaying frame carries a seesaw frame which is rockable with reference thereto about one or more horizontal axes disposed in the central longitudinal symmetry plane of the swaying frame. Two ski boot supporting platforms are mounted on the seesaw frame at the opposite sides of the symmetry plane of the swaying frame, and each such platform is tiltable about a longitudinally extending horizontal axis, turnable about a vertical axis and/or movable lengthwise toward the front or rear end of the swaying frame, always against the opposition of one or more springs which tend to maintain the platform in a neutral position. The seesaw frame enables the user to move one of the platforms downwardly with attendant automatic upward movement of the other platform and vice versa, preferably against the opposition of one or more leaf springs.

BACKGROUND OF THE INVENTION 
The present invention relates to exercising apparatus in general, and more 
particularly to improvements in apparatus which render it possible to 
carry out exercises in imitation of skiing, especially downhill and slalom 
runs. 
An exercising apparatus which is to be used by a budding or experienced 
downhill or slalom skier should meet several requirements including 
enabling the user to carry out (more or less automatically) movements of 
the type expected from a downhill or slalom skier as well as to strengthen 
certain muscles which are active during running on snow. As a rule, the 
movements include (depending on the terrain and style of the skier) the 
following individual movements: 
(1) A more or less pronounced up-and-down movement. 
(2) Stressing of the outer ski in a curve with simultaneous lowering of the 
outer ski. 
(3) Inclination of the skis (edge setting) so that their inner edges are in 
contact with the snow in a turn. 
(4) Turning of feet with the toes facing inwardly in the turn. 
(5) Longitudinal shifting of feet with the inner ski located ahead of the 
outer ski in a turn. 
The majority of movements involve an up-and-down movement with a lowermost 
position during the making of a turn with the smallest radius. 
Alternatively, the skier can also lower his or her body while running 
straight downhill; this involves running with the upper part of the body 
relatively motionless but with a pronounced leg action, particularly an 
activity of muscles in the thighs. The turns are made with pronounced 
straightening of the knee joints. 
An exercising apparatus which is to be used by downhill and/or slalom 
skiers should be capable of enabling the user to perform the 
above-enumerated movements as well as to oppose such movements with a 
requisite force which must be overcome by the user who thereby builds his 
or her muscles and becomes aware of the conditions under which stressing 
of certain muscles or groups of muscles takes place. 
Heretofore known exercising apparatus are constructed and assembled to 
facilitate certain types of exercises as well as to enable the user to 
improve his or her balance and to strengthen certain muscles which are 
active during skiing. For example, German Offenleguntsschrift No. 19 26 
816 discloses an exercising apparatus with pedals which can be caused to 
move up and down under the action or against the opposition of springs 
tending to maintain the pedals in a neutral position. In addition, the 
apparatus of this German printed publication allows for independent 
movements of pedals against the opposition of resilient means. 
Nevertheless, the versatility of the apparatus is rather limited because 
the user cannot move his or her feet forwardly, because the apparatus does 
not embody any means which would permit each foot to turn about a vertical 
axis, because the apparatus does not permit the boots to move to positions 
corresponding to edge setting of the skis, and because the apparatus does 
not provide any simulated relief for the heels in the raised stage. 
German Utility Model No. 82 02 544 discloses a pivotable lever whose free 
end portion carries a platform for ski boots and is pivotable from a 
neutral position against the opposition of a strong spring. The 
inclination of the pivot axis for the lever is adjustable within certain 
limits and the lever can be pivoted about such axis to both sides of the 
neutral position. Any such pivoting of the lever involves a very 
pronounced twisting of feet from the positions they would occupy during a 
straight downhill run. Moreover, the apparatus of this Utility Model does 
not permit any forward shifting of the boots and/or edge setting and/or 
up-and-down movements of the boots. The apparatus merely enables the user 
to practice a single movement (namely, lowering of the body to thereby 
reduce the pressure upon the skis) but the apparatus does not allow for 
any appreciable strengthening of muscles in the thighs of the user. 
A modification of the just discussed prior exercising apparatus is 
disclosed in German Offenlegungsschrift No. 18 06 893. The modified 
apparatus allows for independent longitudinal movements of two tiltable 
boot-supporting platforms against the opposition of springs. However, such 
apparatus does not permit any up-and-down movements of the platform 
independently of each other and/or any turning of the platforms about 
vertical axes. 
A rather complex and expensive exercising apparatus is disclosed in German 
Offenlegungsschrift No. 23 58 117. This apparatus allows for lateral 
movements of platforms for the boots in parallelism with one another in 
response to appropriate movements of the user's body. The last stages of 
lateral movements are damped by springs. The platforms are mounted on 
substantially universal joints which render the mounting of such platforms 
highly unstable. Moreover, the resistance of platforms to various 
movements of the legs and feet is minimal so that the apparatus is 
incapable of building muscles and/or automatically generating forces which 
must be overcome by a skier in the course of an actual run down a slope. 
The apparatus of this German printed publication is intended for use by 
highly skilled skiers but is not suitable for beginners or weekend skiers. 
A further exercising apparatus is disclosed in German Pat. No. 22 24 798. 
This apparatus does not permit for up-and-down movements of the boots 
and/or for edge setting of the platforms so that its ability to prepare a 
skier for downhill or slalom skiing is limited, both as regards the 
practice of required movements as well as concerning the strengthening of 
some or all of the muscles which are used by the skier in the course of a 
downhill or slalom run. 
An apparatus which also belongs to the category of the aforediscussed 
exercising apparatus is disclosed in German Offenlegungsschrift No. 25 15 
570. The apparatus of this prior publication allows for independent 
forward movements of the platforms for ski boots as well as for 
simultaneous movements of both platforms about a common substantially 
vertical pivot axis which is located in front of and is remote from the 
platforms. A certain amount of tilting movement of the platforms is also 
possible. However, neither platform is movable up or down against a 
pronounced restoring force. In fact, none of the afore-enumerated 
movements are carried out against the resistance of springs so that the 
apparatus is incapable of performing any noticeable muscle building 
action. In addition, and in view of the absence of any means for opposing 
various movements of the platforms, the apparatus of this German printed 
publication does not enable the user to acquire the ability to carry out a 
number of different movements, always from a given neutral position and 
back to such neutral position. On the contrary, the user must memorize the 
neutral positions which is not conducive to an exercise that more or less 
compels the user of the exercising apparatus to acquire the ability to 
automatically move the boots to neutral positions as shown as the need for 
edge setting of skis, turning of heels in the bindings, forward or 
rearward movements of the boots, upward and downward movements of the 
boots and/or any combination of such movements is terminated. 
Still another prior art apparatus for use by skiers or prospective skiers 
is disclosed in German Offenlegungsschrift No. 15 78 640. The apparatus of 
this printed publication employs a wheel-mounted conveyance which is 
designed for travel along a pair of slightly convex rails and has 
platforms for the boots of the user. There is no provision for springs or 
other resilient means which could return the conveyance to a neutral 
position with a pronounced force. Basically, the apparatus of this German 
printed publication enables the user to perform a small number of 
movements without any muscle building or other conditioning of the body. 
The conveyance allows for slight longitudinal movements of the platforms 
and the platforms are also free to tilt to a certain extent against the 
opposition of springs. However, the platforms cannot turn about vertical 
axes and they do not permit the legs to perform the very important 
up-and-down movements with attendant muscle building action. 
It will be seen that the apparatus which are presently used, or proposed to 
be used, as exercising machines by downhill or slalom skiers are incapable 
of furnishing a full range of possibilities to develop all muscles which 
are used in the course of such activities as well as to enable the user to 
practice each and every movement which must be performed with and/or 
relative to the skis on a snow-covered slope. 
OBJECTS AND SUMMARY OF THE INVENTION 
An object of the invention is to provide a universal exercising apparatus 
which enables the user to perform all such exercises which are important 
for his or her safety on a snow-covered slope during a downhill run or an 
analogous run. 
Another object of the invention is to provide an exercising apparatus which 
allows for adequate building of all muscles that must be strengthened for 
safe and satisfactory skiing in general and for a downhill, slalom or 
giant slalom run in particular. 
A further object of the invention is to provide an apparatus which renders 
it possible to perform a number of different exercises which closely 
resemble the movements that are performed on flat or uneven snow-covered 
terrain. 
An additional object of the invention is to provide an exercising apparatus 
which is especially suitable for strengthening of the muscles in the 
thighs and buttocks. 
Another object of the invention is to provide an apparatus which is 
relatively simple and compact, wherein each and every movement which is to 
be performed by the user is or can be opposed by a spring force of optimum 
magnitude, and which can be used with equal advantage and equal desirable 
results by novices, weekend skiers or highly advanced amateur or 
professional skiers. 
An additional object of the invention is to provide an apparatus which can 
be readily adjusted so as to be best suited for use by children, 
teenagers, male or female skiers, adults, beginners lacking any previous 
exercise or actual skiing experience, or advanced and professional skiers. 
Another object of the invention is to provide an apparatus which can be 
designed or adjusted to take into consideration the weight of the user. 
A further object of the invention is to provide an exercising apparatus 
which can be used for indoor practicing of all kinds of movements or 
sequences of movements which come into question during a downhill, slalom, 
giant slalom or other run and which enables the user to perform such 
movements in a manner that comes closer to actual movements on a 
snow-covered terrain than is achievable with heretofore known apparatus. 
An additional object of the invention is to provide a novel and improved 
method of exercising various parts of the human body preparatory to or in 
lieu of downhill or slalom running. 
Another object of the invention is to provide the apparatus with novel and 
improved means for supporting the platforms for the boots or feet of the 
user. 
A further object of the invention is to provide an apparatus which can be 
used as a superior substitute for two or more different types of 
conventional apparatus. 
Another object of the invention is to provide an apparatus whose 
versatility considerably exceeds that of conventional exercising apparatus 
and which can be used in homes, gyms, ski lodges and other establishments 
which house or are likely to be frequented by skiers or budding skiers. 
Still another object of the invention is to provide an apparatus which is 
safer than heretofore known apparatus, which is not likely to soil or tear 
the garments of the users, and which requires a minimum of training for 
utilization with optimum results. 
The invention is embodied in an exercising apparatus which can be used with 
particular advantage by downhill skiers. The apparatus comprises a 
stationary main frame and a swaying frame having a first and a second pair 
of aligned front and rear links each including a lower end portion 
pivotally mounted in the main frame and an upper end portion. The swaying 
frame further comprises carrier means which is pivotally secured to the 
upper end portions of the links for angular movement about parallel 
substantially horizontal axes (the carrier means can comprise front and 
rear end wa1ls which are respectively pivoted to the front and rear links, 
longitudinally extending connecting rods secured to the two end walls and 
a seesaw frame mounted on the connecting rods). The apparatus further 
comprises resilient means (e.g., at least one set of strong coil springs) 
for biasing the swaying frame to a neutral position in which the links are 
disposed at the opposite sides of a first central longitudinal vertical 
symmetry plane extending between the lower end portions of the two pairs 
of links. The links are pivotable with reference to the main frame to 
either side of the first symmetry plane against the opposition of the 
resilient means and the swaying frame has a second central longitudinal 
vertical symmetry plane with coincides with the first symmetry plane in 
the neutral position of the swaying frame. The apparatus further comprises 
first and second boot supporting platforms which are mounted on the 
carrier means at the opposite sides of the second symmetry plane and have 
third central longitudinal symmetry planes. The distance between the 
second symmetry plane and each third symmetry plane exceeds the distance 
between the second symmetry plane and each of the aforementioned 
horizontal axes. 
The pairs of links are preferably mirror symmetrical to each other with 
reference to the first plane in the neutral position of the swaying frame, 
and the length of each front link preferably matches the length of the 
respective rear link. Also, the links of the first pair are preferably at 
least substantially parallel to the links of the second pair. 
As mentioned above, the carrier means preferably comprises a seesaw frame 
having first and second portions which are mirror symmetrical to each 
other with reference to the second plane. The seesaw frame is rockable 
with reference to the swaying frame about at least one second 
substantially horizontal axis which is disposed in the second plane. This 
ensures that one portion of the seesaw frame moves upwardly while the 
other portion of the seesaw frame moves downwardly and vice versa. The 
first and second platforms are mounted on the respective (first and 
second) portions of the seesaw frame. Such apparatus preferably further 
comprises means (e.g., elastically deformable shock absorbers) for 
limiting the rocking movements of the first and second portions of the 
seesaw frame with reference to the swaying frame. Still further, such 
apparatus preferably comprises one or more leaf springs or other suitable 
resilient means for biasing the seesaw frame to a neutral position in 
which the platforms are or can be disposed at or close to the same level. 
In accordance with a presently preferred embodiment of the invention, the 
seesaw frame comprises an upper section and a preferably identical or 
similar but independent lower section as well as means for compelling the 
two sections to perform pivotal movements about two discrete second axes 
which are located in the second symmetry plane. The compelling means can 
comprise distancing elements which serve to maintain the two sections of 
the seesaw frame in two discrete parallel planes each of which includes 
one of the second horizontal axes. Each portion of the seesaw frame 
includes one-half of the upper and one-half of the lower section of such 
frame. Each section of the seesaw frame preferably includes a pair of 
longitudinally extending coupling members (e.g., rods having a circular 
cross-sectional outline) and such apparatus can further comprise means for 
varying the distance between the coupling members of each section and/or 
between the coupling members of the upper and lower sections. The coupling 
members of each section are disposed at the opposite sides of the second 
symmetry plane, i.e., each portion of the seesaw frame can be said to 
comprise at least one coupling member. The platforms can be mounted for 
movement lengthwise of the respective coupling member or members, and the 
apparatus preferably further comprises resilient means for yieldably 
urging the platforms to predetermined neutral positions as considered in 
the longitudinal direction of the respective coupling member(s). 
The apparatus can further comprise pivot means which define for each of the 
platforms a substantially vertical pivot axis about which the respective 
platform is turnable relative to the corresponding portion of the seesaw 
frame. Such apparatus preferably also comprises springs which serve to 
yieldably oppose pivotal movements of the platforms from predetermined 
neutral positions with reference to the corresponding portions of the 
seesaw frame, i.e., to predetermined angular positions so that the third 
symmetry planes are at least substantially parallel to the first and 
second symmetry planes. The springs of each pair are preferably arranged 
to act substantially tengentially of the respective pivot means and in the 
opposite directions so that one spring of each pair stores energy when the 
other spring of the same pair dissipates energy and vice versa. 
The apparatus preferably further comprises means for adjusting the bias of 
resilient means which urges the swaying frame to its neutral position. To 
this end, the main frame preferably comprises a transversely extending 
bridge disposed at the front or rear end of the swaying frame and serving 
as a support for the adjusting means. The adjusting means can comprise a 
holder (e.g., a horizontal beam) which is directly or indirectly connected 
with the resilient means, a nut in the bridge, a substantially vertical 
feed screw which meshes with the nut and is connected with the holder, and 
means for rotating the feed screw with reference to the nut to thereby 
move the holder up or down and to thus increase or reduce the bias of the 
resilient means. The means for rotating the feed screw can comprise a 
crank which includes or constitutes a seat for the user of the apparatus. 
The platforms are preferably turnable with reference to the carrier means 
(most preferably about the axes of the corresponding coupling members) 
about longitudinally extending axes which are parallel or nearly parallel 
to the horizontal axes of the means which connect the carrier means to the 
upper end portions of the links. Such apparatus preferably further 
comprises means for yieldably biasing the platforms to predetermined 
neutral positions with reference to the swaying frame, i.e., to 
predetermined angular positions. 
In accordance with a presently preferred embodiment of the invention, the 
versatility of the apparatus is highly satisfactory if the platforms are 
tiltable within limites relative to the swaying frame about longitudinal 
axes (of the aforementioned coupling members), if the platforms are 
turnable within limits with reference to the carrier means about 
substantially vertical axes, if each of the platforms is shiftable 
lengthwise within limits relative to the carrier means in parallelism with 
the horizontal pivot axes for the carrier means, and if each platform is 
movable within limits up and down with reference to the swaying frame. As 
mentioned above, resilient means can yieldably oppose at least one of the 
just mentioned tilting, turning, shifting and up-and-down movements of the 
platforms, and some or all of the resilient means are preferably 
adjustable to select the forces which the user must overcome in order to 
induce the platforms to perform the respective movements with reference to 
the swaying frame and/or carrier means. 
The novel features which are considered as characteristic of the invention 
are set forth in particular in the appended claims. The improved apparatus 
itself, however, both as to its construction and its mode of operation, 
together with additional features and advantages thereof, will be best 
understood upon perusal of the following detailed description of certain 
specific embodiments with reference to the accompanying drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring first to FIGS. 1 to 3, there is shown an apparatus which can be 
used for the practice of skiing, especially for practicing downhill or 
slalom runs, and more particularly, for exercising those parts of the body 
whose conditioning is especially important for a safe and satisfactory 
downhill or slalom run. The apparatus comprises a stationary main frame 20 
which is assembled of profiled metallic members and carries 
floor-contacting legs 21 of rubber or another suitable material which not 
only exhibits a certain amount of resiliency but also reduces the 
likelihood of slippage of the frame 20 along the floor. The frame 20 
includes a transversely extending front frame member 20a whose end 
portions extend laterally beyond the corresponding longitudinal frame 
members 20c. The free end of each end portion of the front frame member 
20a is provided with a forwardly extending lug 22 carrying an upwardly 
extending externally threaded stub shaft 22a mating with the nut of a 
clamping handle 23 which can hold in a selected angular position a lever 
24 extending forwardly of the respective end portion of the frame member 
20a. The front end portion of each lever 24 supports a variable-length 
pole 25 which is assembled of several telescopically connected sections 
the uppermost one of which carries a handgrip member 26. The length of the 
poles 25 can be varied within a wide range so as to place the handgrip 
members 26 to optimum positions for engagement by the hands of the person 
utilizing the apparatus. Moreover, the nuts of the clamping handles 23 can 
be detached from the respective stubs 22a to allow for detachment of the 
levers 24 and poles 25 in order to reduce the overall dimensions of the 
apparatus for the purpose of storage or transport. It is also possible to 
pivot the levers 24 in front of the frame member 20a so that the 
apparatus occupies less space even if the poles 25 are not completely 
detached prior to placing the apparatus into storage or prior to transport 
of the apparatus to a dealer, to a customer or to another destination. The 
reference characters 27 and 27' denote two plate-like platforms which 
serve as a means for supporting the boots of the person using the 
apparatus. 
The apparatus which is shown in FIGS. 1 to 3 preferably comprises two 
halves which are mirror symmetrical to one another with reference to a 
longitudinal vertical symmetry plane X--X extending midway between the 
platforms 27, 27' and at right angles to the front frame member 20a. The 
main frame 20 further includes a transversely extending rear frame member 
20b which is parallel to the front frame member 20a and need not extend 
laterally beyond the longitudinal frame members 20c. The frame members 
20a, 20b are connected to each other by two parallel horizontal shafts 28, 
28' which are disposed at least substantially midway between the 
longitudinal frame members 20c. The front end portions of the shafts 28, 
28' extend forwardly beyond the frame member 20a and define pivot axes for 
two mirror symmetrical upwardly extending links 29, 29' of identical 
length. The rear end portions of the shafts 28, 28' extend rearwardly 
beyond the frame member 20b and respectively define pivot axes for two 
additional mirror symmetrical links 30, 30' (see also FIGS. 4 and 5). The 
links 29, 30 are non-rotatably secured to the respective end portions of 
the shaft 28 by radially extending pins or the like (not shown), and the 
links 29', 30' are non-rotatably secured to the respective end portions of 
the shaft 28' in similar fashion. The upper end portions of the front 
links 29, 29' are turnably connected with a trapeziform plate-like front 
end wall 31 whose width increases in a direction downwardly toward the 
front frame member 20a, and the upper end portions of the rear links 30, 
30' are articulately connected with a similar trapeziform plate-like rear 
end wall 32. The end walls 31 and 32 constitute component parts of a 
swaying frame 99 which can move back and forth with the links 29-30' about 
the axes of the shafts 28 and 28', i.e., to the left and to the right of 
the symmetry plane X--X as viewed in FIG. 3. The distance between the axes 
of the pivot members 129, 129' which articulately connect the links 29, 
29' to the front end wall 31 is the same as that between the axes of the 
shafts 28, 28'. The means for rigidly connecting the end walls 31, 32 to 
each other comprises two elongated parallel horizontal connecting rods 33, 
34 which are disposed at different levels (see FIG. 2) and cooperate with 
the links 29-30' to ensure that the orientation of the swaying frame 99 
(when the links 29-30' pivot about the axes of the respective shafts 28, 
28') remains unchanged. At such time, the end walls 31, 32 move along 
arcuate paths back and forth alternately toward the one and the other 
longitudinal frame member 20c at a level above the main frame 20. The 
extent of such movements of the swaying frame 99 including the end walls 
31 and 32 is limited by elastic stops 35 which are mounted on the front 
and rear frame members 20a, 20b. The connecting rods 33 and 34 constitute 
an optional feature of the swaying frame 99 because the aforediscussed 
nature of back-and-forth movements of this frame is ensured by the links 
29-30' in cooperation with the shafts 28, 28' and pivot members which 
secure the upper end portions of the links to the respective end walls 31, 
32. The main purpose of the connecting rods 33, 34 is further stiffen or 
reinforce the frame 99 so as to further enhance the stability and safety 
of the apparatus. As can be seen in FIGS. 4 and 5, the configuration of 
those edge faces of the rear links 30, 30' which face one another is such 
that these links cannot interfere with pronounced back-and-forth movements 
of the frame 99 all the way into contact with the elastic stops 35 on the 
frame members 20a and 20b. The same holds true for the configuration of 
those edge faces of the front links 29, 29' which face one another. To 
this end, the just discussed edge faces of the links 29-30' are provided 
with cutouts so as to provide ample room for swaying of each link through 
an angle of nearly 180.degree.. 
The main frame 20 of the apparatus further comprises a transversely 
extending bridge 36 which extends between the longitudinal frame members 
20c to a level well above the general plane of the main frame (see FIGS. 2 
and 3). The bridge 36 is an inverted U-shaped structure (actually, the 
shape of the bridge resembles a trapeze) having two upwardly sloping 
convergent flanges 36a whose lower end portions are affixed to the 
respective longitudinal frame members 20c and the upper end portions of 
which are rigidly secured to one another by a horizontal web 37. The 
central portion of the web 37 includes or constitutes a spindle nut 38 
which has a tapped vertical through bore and is in mesh with the external 
threads of a rotary feed screw 39. The upper end portion of the feed screw 
39 is connected with a crank 40 having an eccentric handle 41 which can be 
actuated by hand in order to move the feed screw 39 axially toward or away 
from the general plane of the main frame 20. The crank 40 constitutes or 
includes a seat for the person using the exercising apparatus. 
The lower end portion of the feed screw 39 is rotatably connected with the 
central portion of a transversely extending horizontal holder or beam 42 
which serves as a means for expanding or for permitting contraction of 
relatively large and strong prestressed coil springs 43. The lower end 
portions of the coil springs 43 are connected with a second horizontal 
holder or beam 44 which has pins 45, 45' extending forwardly into 
complementary sockets 30a, 30a' of the rear links 30 and 30'. By rotating 
the crank 40 via handle 41, the user of the apparatus can select the 
tension of the springs 43, i.e., the resistance which the user encounters 
to swaying of the frame 99 including the end walls 31 and 32 between the 
two pairs of elastic stops 35 on the frame members 20a and 20b. 
The bridge 36, the major part of the feed screw 39, the nut 38, the beams 
42, 44 and the springs 43 are partially confined in a housing or shell 46 
which is secured to the main frame 20 as well as to the bridge 36. A 
second housing or shell 47 constitutes or resembles a shroud which 
partially confines the front portion of the frame 99. The purpose of the 
housings 46, 47 is to enhance the appearance of the apparatus, to conceal 
those parts which require oiling or another type of lubrication, and to 
reduce the likelihood of injury to the user. 
FIGS. 4 and 5 show on an enlarged scale the bridge 36, the springs 43, the 
means for tensioning the springs 43, as well as the rear portion of the 
frame 99. FIG. 4 shows the frame 99 in a neutral position in which the 
springs 43 extend substantially vertically, and FIG. 5 shows these springs 
in stressed condition with the swaying frame 99 deflected all the way to 
one of its two end positions, namely, into abutment with the corresponding 
elastic stops 35 on the frame members 20a and 20b. Thus, when the frame 99 
assumes the end position of FIG. 5 (or the other end position), the 
springs 43 store a maximum amount of energy. The arrow 48 denotes in FIG. 
4 the directions in which the upper holder or beam 42 can be moved by the 
feed screw 39 in order to change the initial stressing of the springs 43. 
Such adjustments will be carried out in order to conform the initial 
stressing of the springs 43 to the weight of the person using the 
apparatus as well as to select the effort which is required to move the 
frame 99 from the neutral position of FIG. 4. 
The platforms 27, 27' are respectively provided with arcuate abutments 49, 
49' for the heels of the boots which are worn by the person using the 
apparatus as well as with straps 50 (see FIG. 2) which can be caused to 
extend over the insteps of the respective feet. The straps 50 are secured 
to the respective abutments 49, 49'. 
The platforms 27 and 27' are mounted on a third frame 51 (hereinafter 
called seesaw frame to distinguish from the main frame 20 and from the 
swaying frame 99) the details of which are shown in FIGS. 6 to 9. The 
frame 51 is articulately connected to the swaying frame 99, and its rear 
portion is a mirror image of its front portion. The same applies for the 
front and rear portions of the frame 99. 
In the embodiment which is shown in FIGS. 1 to 9, the seesaw frame 51 
comprises an upper section 52 and an independent lower section 53. The 
sections 52, 53 are respectively mounted on the upper and lower connecting 
rods 33, 34 of the frame 99 and are compelled to rock in parallelism with 
each other by distancing elements which ensure that the lower section 53 
invariably remains parallel to the upper section 52, i.e., that such 
sections are invariably located in two parallel planes. More specifically, 
the upper section 52 of the frame 51 comprises a front and a rear 
transverse brace 54 as well as two elongated rod-like parallel coupling 
members 55, 55' which connect the end portions of the front brace 54 with 
the end portions of the rear brace 54. The median portions of the braces 
54 are free to pivot back and forth on the upper connecting rod 33. The 
lower section 53 of the frame 51 comprises front and rear transverse 
braces 56 and elongated rod like coupling members 57, 57' which are 
parallel to each other and are respectively adjacent to the coupling 
members 55, 55'. The braces 56 are free to pivot back and forth on the 
lower connecting rod 34. The coupling members 55, 55', 57, 57' 
respectively carry disc-shaped distancing elements 58, 58', 59, 59' which 
ensure that the braces 54 are invariably parallel to the braces 56 
irrespective of the inclination of these braces with reference to the main 
frame 20. The distancing elements 58, 58' continuously abut against the 
respective distancing elements 58', 59' and such distancing elements can 
constitute idler rollers to reduce the resistance to rocking of the seesaw 
frame 51. Split rings, cotter pins or other suitable means can be provided 
to hold the distancing elements 58-59' against axial movement along the 
respective coupling members 55, 55', 57 and 57'. The distancing elements 
58-59' allow for rocking of the two sections 52, 53 of the frame 51 
without allowing the two sections to come into actual contact with one 
another. Thus, the distance between the coupling members 55, 57 and 55', 
57' is constant in each angular position of the braces 54, 56 relative to 
the respective connecting rods 33, 34. The plane including the axes of the 
upper coupling members 55, 55' is invariably parallel to the plane 
including the axes of the lower coupling members 57, 57'. Such planes 
respectively include the axes of the connecting rods 33 and 34. FIG. 6 
shows the sections 52, 53 of the seesaw frame 51 in two parallel 
horizontal planes, and FIG. 9 shows such sections in two inclined planes 
which are parallel to each other. These sections can seesaw between the 
end positions which are shown in FIG. 9 by solid lines and the end 
positions which are indicated in FIG. 9 by two parallel phantom lines. The 
sections 52, 53 assume the horizontal positions of FIG. 6 in the neutral 
position of the seesaw frame 51. 
The apparatus further comprises means for limiting the extent of movement 
of the seesaw frame 51 relative to the swaying frame 99 including the end 
walls 31 and 32. Such limiting means comprises projections 60 which are 
provided on the end walls 31, 32 and extend below the braces 56 of the 
frame 51. The projections 60 comprise suitably inclined stop faces 60a 
(see particularly FIG. 6) for elastic protuberances 61 at the undersides 
of the braces 56. The protuberances 61 can be said to constitute simple 
shock absorbers which damp the last stage of movement of the seesaw frame 
51 to each of its end positions. 
Still further, the apparatus comprises means for automatically returning 
the frame 51 to and for normally maintaining the frame 51 in the neutral 
position of FIG. 6. Such returning means comprises suitably configurated 
leaf springs 63 which are secured (by bolts 62 or analogous fasteners) to 
the projections 60 midway between the respective stop faces 60a and have 
pairs of prongs with convex upper surfaces abutting against the undersides 
of the corresponding braces 56. When the seesaw frame 51 assumes the one 
or the other end position, the prongs of the leaf springs 63 enter the 
corresponding recesses 60b which are provided therefor in the respective 
projections 60. 
As can be seen in FIGS. 1 and 2, the platforms 27, 27' are respectively 
mounted on the upper coupling members 55, 57 and 55', 57' of the seesaw 
frame 51. Each of these platforms is movable lengthwise of the 
corresponding coupling members, i.e., toward the front end wall 31 or 
toward the rear end wall 32 of the frame 99. Moreover, and since the frame 
51 can be rocked between the two end positions one of which is fully shown 
in FIG. 9, the user of the apparatus can lift or lower the right or the 
left foot and the corresponding boot by causing the frame 51 to move from 
the neutral position of FIG. 6. The foot which exerts pressure upon the 
respective platform 27 or 27' moves downwardly. However, the platforms 27, 
27' do not or need not change their orientation in response to rocking of 
the frame 51 because each of these platforms is secured to two coupling 
members which are parallel to and are disposed one above the other. This 
can be readily seen for the platform 27 by looking at FIG. 2 wherein the 
platform 27 is provided with a first sleeve 27A surrounding the upper 
coupling member 55 and the first sleeve carries a second sleeve 27B 
surrounding the lower coupling member 57. 
The apparatus of the present invention can be used as a means for 
practicing different types of races, e.g., downhill and slalom or giant 
slalom. Therefore, it may be advantageous for the user to move his or her 
feet nearer to or further away from each other (as considered in the 
longitudinal direction of the main frame 20). For this purpose, the braces 
54, 56 may be of the extendable and contractible (variable length) type. 
FIGS. 1 and 2 further show portions of additional housings or shells 64, 65 
which respectively cooperate with the aforementioned housings 47, 46 to 
further contribute to safety and eye-pleasing appearance of the apparatus. 
The upper portion of the housing 64 is partially overlapped by the upper 
portion of the housing 47, and the housing 64 conceals or overlies the 
inner sides of the front links 29, 29'. Moreover, the housing 64 conceals 
the means which connect the swaying frame 99 with the front portion of the 
seesaw frame 51. The housing 65 conceals the means for connecting the 
frame 99 with the rear portion of the frame 51. The housings 64, 65 
further cooperate with the housings 46, 47 to reduce the likelihood of 
soiling of the user's hands, boots or garmets by lubricant. 
The vertical plane Z--Z (FIG. 6) is the longitudinal symmetry plane of the 
swaying frame 99 and coincides with the plane X--X when the swaying frame 
assumes the neutral position of FIG. 4. The longitudinal symmetry planes 
Y--Y and Y'--Y' of the platforms 27 and 27' are disposed at the opposite 
sides of the symmetry plane Z--Z, and the distance between the plane Z--Z 
and each of the planes Y--Y, Y'--Y' exceeds the distance between the plane 
Z--Z and the horizontal axis of the pivot member 129 or 129'. The seesaw 
frame 51 can be said to include a first portion 151 at one side and a 
mirror symmetrical second portion 151' at the other side of the symmetry 
plane Z--Z. The portion 151 includes one-half of each of the sections 52, 
53, and the portion 151' includes the other half of each of these 
sections. The platform 27 is mounted on and can move up and down with the 
portion 151, and the platform 151'. The axes of the connecting rods 33, 34 
are parallel to the axes of the pivot members 129, 129' and to the axes of 
pivot members which connect the rear end wall 30 with the upper end 
portions of the links 30, 30'. The parts 31 to 34 can be said to 
constitute a carrier for the seesaw frame 55, and such carrier is part of 
the swaying frame 99 which sways about the pivot axes defined by the 
shafts 28, 28' while the seesaw frame pivots about the horizontal axes of 
the connecting rods 33, 34. 
The aforediscussed relationship of the distances between the planes Z--Z 
and Y--Y, Y'--Y' on the one hand and the plane Z--Z and the axes of the 
pivot members 129, 129' on the other hand renders it possible to move the 
portion 151 of the seesaw frame 51 downwardly (with attendant upward 
movement of the portion 151') or vice versa by the simple expedient of 
shifting the body weight of the person using the improved practicing or 
exercising apparatus. By shifting the weight of his or her body onto the 
one or the other foot, the person using the apparatus must overcome the 
resistance of the springs 63 which tend to maintain the frame 51 in the 
neutral position of FIG. 6. The other movements of the platforms 27, 27' 
(namely tilting movements about the respective connecting rods 55, 55', 
longitudinal movements in the axial direction of the respective connecting 
rods 55, 55', and pivotal movements about the axes of the respective pivot 
pins 75, 75') against the opposition of the respective resilient means 
enable the user to practice additional movements which will be performed 
on a ski slope and to simultaneously build the corresponding muscles, 
especially in the thighs and the buttocks. Each and every spring is or can 
be adjusted so as to change its bias depending on the age and/or sex 
and/or weight and/or degree of advancement of the person using the 
apparatus. 
A person resting his or her boots on the platforms 27, 27' can cause the 
seesaw frame 51 to rock to the solid-line end position of FIG. 9 by 
exerting pressure with the respective foot. At the same time, such person 
can cause the swaying frame 99 to leave the neutral position of FIG. 4 by 
causing the springs 43 to store additional energy so that the parts 31, 
32, 33 and 34 sway about the pivot axes which are defined by the shafts 28 
and 28'. For example, the person using the improved apparatus can move the 
frame 99 to the position which is shown in FIG. 5 by applying one-sided 
pressure to the lower beam 44 via rear end wall 32 of the frame 99. By 
alternatively depressing the platforms 27, 27', the person using the 
apparatus strengthens the muscles of his or her thighs and buttocks. 
Furthermore, such exercise is beneficial to the circulatory system. 
In order to even more accurately simulate the conditions which prevail 
during a downhill or slalom race, especially to more accurately imitate 
the various swaying movements which are performed during skiing, the 
apparatus of the present invention can be further equipped with means for 
yieldably opposing movements of the platforms 27, 27' from horizontal 
planes so that the boots can assume positions corresponding to those when 
the skis are running on edge rather than lying flat against the 
snow-covered ground. Moreover, it is desirable and advantageous to 
construct and assemble the apparatus in such a way that the feet of the 
user can perform other exercises, preferably against the resistance of 
resilient means. Such additional exercises can involve turning the tips of 
the toes inwardly while exerting pressure with the heels as well as 
slightly or extensively shifting the feet relative to each other in the 
longitudinal direction of the apparatus by moving forwardly that foot 
which is at the inner side of the curve during skiing. In order to carry 
out such additional exercises, the platforms can be secured to the swaying 
frame 51 in a number of different ways as shown in FIGS. 10 to 19. Since 
the platforms 27 and 27' are mirror symmetrical to one another, it 
suffices to describe the means for facilitating and yieldably opposing 
various movements of one of these platforms. 
FIGS. 10 to 13 illustrate the manner in which the platform 27 can be caused 
to tilt back and forth about the axis of the coupling member 55. As shown 
in FIG. 2, the platform 27 can be mounted on two coupling members, namely 
on the coupling member 55 of the upper section 52 and on the coupling 
member 57 of the lower section 53 of the seesaw frame 51. First of all, 
the platform 27 is or can be mounted on an elongated sleeve 164 in such a 
way that it can turn relative thereto about a vertical axis. The sleeve 
164 corresponds to the sleeve 27A of FIG. 2 and slidably surrounds the 
upper coupling member 55 of FIGS. 10 to 13. Since the coupling member 55 
is a solid cylindrical rod, the sleeve 164 can turn about its axis as long 
as such movement is not prevented by the lower coupling member 57 whose 
diameter is smaller than that of the coupling member 55. As can be readily 
seen in FIGS. 11 and 12, the sleeve 164 supports or is integral with two 
casings 165 which flank the lower coupling member 57 and contain springs 
66 tending to maintain the platform 27 in a horizontal position. The 
length of the casings 165 can be a small fraction of the axial length of 
the sleeve 164. Each of the illustrated springs 66 is a relatively strong 
coil spring which reacts against a downwardly extending outer wall 165a of 
the respective casing 165 and bears against the bottom wall of a hollow 
cupped plunger or pusher 67 arranged to directly contact the corresponding 
side of the coupling member 57. Each spring 66 surrounds a guide post 68 
in the form of a pin which extends outwardly through the respective outer 
wall 165a and has an externally threaded outer end mating with a nut 69. 
The post 68 is reciprocably guided in the respective outer wall 165a and 
its inner end portion is connected to the corresponding pusher 67. When 
the platform 27 is held in the horizontal position of FIG. 11, the springs 
66 are free to expand so that both pushers 67 bear against the coupling 
member 57 and the nuts 69 bear against the outer sides of the respective 
outer walls 165a. The bias of the left-hand spring 66 of FIG. 11 is the 
same as that of the right-hand spring; therefore, these springs normally 
maintain the plate 27 in the horizontal position of FIG. 11. However, the 
user of the apparatus can twist his or her feet so as to cause the sleeve 
164 to turn clockwise or counterclockwise, as viewed in FIG. 11, e.g., to 
the position which is shown in FIG. 12. This entails a more or less 
pronounced stressing of one of the springs 66 and a corresponding 
reduction of the bias of the other spring. The state of equilibrium is 
restored automatically when the user ceases to twist his or her ankle so 
that the platform 27 can reassume the neutral position of FIG. 11. 
FIGS. 14 to 16 illustrate the manner in which the platform 27 is movable in 
the longitudinal direction of the corresponding coupling members 55 and 57 
to and from a central or neutral position. The left-hand end position of 
the platform 27 is indicated in FIG. 14 by phantom lines, as at 270, and 
the phantom lines 2700 indicate the other (right-hand) end position of the 
platform 27. As can be seen in FIG. 15, the end portions 164a of the 
sleeve 164 constitute friction bearings which snugly surround the upper 
coupling member 55 and confine two coil springs 70, 71 which surround the 
coupling member 55. A split ring 72 is recessed into a circumferential 
groove of the coupling member 55 and is located midway between the 
friction bearings 164a when the platform 27 assumes the neutral position 
of FIG. 15. The split ring 72 can be said to constitute a collar of the 
coupling member 55, and its purpose is to stress the spring 70 or 71 in 
conjunction with the corresponding friction bearing 164a, depending upon 
the direction of movement of the platform 27 longitudinally of the seesaw 
frame including the coupling member 55. The bias of the spring 71 
preferably matches that of the spring 70 so that the two springs normally 
maintain the platform 27 in the neutral position of FIG. 15 as long as the 
user of the apparatus does not pull the platform 27 forwardly toward the 
end position 270 of FIG. 14 (by the corresponding instep strap 50) or as 
long as the user does not push the platform 27 toward the end position 
2700 by way of the heel abutment 49. 
FIG. 16 illustrates one presently preferred mode of separably securing the 
sleeve 164 to the platform 27. The securing means includes a hollow 
casting 73 which is preferably an integral part of the sleeve 164 and is 
disposed at one side of the coupling member 55. The casting 73 defines a 
hole 74 for a pivot pin 75 which extends at right angles to the plane of 
the platform 27 and the upper end portion of which extends into a socket 
27D which is provided in the platform in register with the hole 74. The 
upper end portion of the pivot pin 75 is a press fit in the socket 27D, 
and the lower end portion of this pin extends downwardly beyond the 
casting 73 and has a circumferential groove for a split ring 76 which 
releasably holds the pin in the hole 74. The structure of FIG. 16 
constitutes a simple but reliable means for separably securing the sleeve 
164 to the platform 27 as well as for preventing any movements of the 
platform with reference to such sleeve except an angular movement about 
the axis of the pivot pin 75. In order to prevent excessive angular 
movements of the platforms relative to the corresponding sleeves, the 
improved apparatus preferably further comprises means for yieldably 
opposing turning of the platforms about the axes of the corresponding 
pivot pins. This is shown in FIGS. 17 to 19 in connection with the 
platform 27' and the corresponding sleeve 164'. The provision of some 
means for limiting or opposing angular movements of the platforms about 
the respective pivot pins (note the pin 75' in FIGS. 18 and 19) is 
desirable and advantageous because this reduces the danger of injury to 
the person using the apparatus. 
The underside of the platform 27' is provided with casings 77' which flank 
the pivot pin 75' and each of which contains a coil spring 78'. The 
casings 77' can form integral parts of the platform 27' which can 
constitute a casting or forging made of steel or any other suitable alloy. 
The inner convolutions of the springs 78' react against the bottom end 
walls 77a' of the corresponding casings 77' and the outer convolutions of 
such springs bear against the side wall of the sleeve 164'. The bias of 
the spring 78' at one side of the pivot pin 75' matches the bias of the 
other spring 78' so that these springs normally cooperate and maintain the 
platform 27' in a neutral position 27N which is shown in FIG. 19 by 
phantom lines. By applying a requisite force to the platform 27' through 
the medium of the heel abutment 49' and the corresponding strap 50 (not 
shown in FIGS. 17 to 19), the user of the apparatus can move the platform 
27' about the axis of the pivot pin 75' between the end positions 27E and 
27E' (both indicated in FIG. 19 by phantom lines). Such movements of the 
platform 27' from the neutral position 27N entail compression of one of 
the springs 78' and a commensurate expansion of the other spring 78'. This 
exercise is helpful because it enables the foot to overcome forces which 
invariably develop or are likely to develop in the course of a downhill or 
slalom run. 
It will be readily appreciated that the basic apparatus of the present 
invention (such basic apparatus preferably comprises the swaying frame 99 
and the seesaw frame 51) can be equipped with one or more additional 
features, such as those respectively shown in FIGS. 10-13, 14-16 and 
17-19. As shown in FIGS. 17 and 19, the platform 27' is equipped with 
means for yieldably opposing the movements about the axis of the pivot pin 
75' as well as with means for yieldably opposing movements of the platform 
in a manner as described for the platform 27 in connection with FIGS. 
12-14. Furthermore, the sleeve 164' of FIGS. 17-19 is movable forwardly or 
backwards against the opposition of the spring 70' or 71'. All such parts 
which are denoted in FIGS. 17-19 by various reference characters but are 
not specifically referred to are identified by numerals which are used in 
FIGS. 12 to 16 but each such numeral is followed by a prime. 
The improved exercising apparatus exhibits a number of important 
advantages. Thus, the apparatus is or can be relatively simple and compact 
so that it occupies little room when it is set up for actual use, in 
storage or during transport. Secondly, the apparatus is highly versatile 
so that it can replace two or more conventional apparatus. Thirdly, the 
apparatus is readily adjustable so as to be ready for use by children, 
adolescents or adults, by male or female skiers, by lightweight or heavier 
person and by beginners, future beginners, weekend skiers or highly 
experienced amateur or professional skiers. Moreover, the apparatus can be 
used by persons who do not intend or do not anticipate to ski but simply 
wish to build certain muscles and/or to carry out certain exercises in 
order to lose weight, to maintain a desired weight or to maintain their 
bodies in good physical shape. Still further, the apparatus can be used by 
skiers who wish to strengthen their bodies and perform a variety of 
movements preparatory to skiing on flat or inclined terrain, by ski 
jumpers, by persons preparing for alpine events or cross country skiing, 
by cyclists, by football players and/or other sportsmen. Other important 
advantages of the improved apparatus are relatively low cost, long useful 
life, safety, low inertia, ability to move each of the platforms and/or 
the swaying frame and/or the seesaw frame automatically to the neutral 
position and adjustability of all or nearly all mobile components. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic and specific aspects of my contribution to 
the art and, therefore, such adaptations should and are intended to be 
comprehended within the meaning and range of equivalence of the appended 
claims.