Exercise apparatus

An exercise device for simulating cross-country skiing includes a plurality of longitudinally extending channel members mounted on cross frame members so as to define elongated slots in which trolleys for foot supporting members and hand engaging members can reciprocate. A control system interconnecting the foot supporting members and hand engaging members includes a main drive pulley interconnecting the foot supporting members for coordinated reciprocal movement and a secondary belt interconnecting the foot supporting members and hand engaging members so that each hand engaging member will reciprocate in an opposite direction to its associated foot supporting member and at a speed of twice that of the foot supporting member. A resistance structure is provided for resisting movement of the trolleys to provide a selected level of exercise.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to exercise apparatus and more 
particularly to an exercise apparatus that is adapted to simulate 
cross-country skiing. 
2. Description of the Prior Art 
While many types of devices and apparatus have been developed and used 
through the years for assisting an individual in obtaining desired 
exercise and particularly cardiovascular exercise, it has only been in 
recent years that the importance of such exercise has been fully 
appreciated. As a result, numerous types of equipment have been developed 
to exercise various parts of the body. In some cases, the equipment is 
designed to develop muscular strength, but in other types of equipment, 
the goal is directed more to cardiovascular benefits, and such exercise 
equipment is commonly referred to as aerobic exercise equipment. 
Most exercise specialists acknowledge that cross-country skiing is one of 
the best forms of aerobic exercise in that both the arms and the legs are 
utilized, thereby more quickly obtaining an elevated heart rate while 
obtaining and maintaining good muscle tone throughout the body. For this 
reason, many types of equipment have been developed in an attempt to 
simulate cross-country skiing so that cross-country skiing movements can 
be performed in an indoor environment. 
There have been numerous cross-country ski simulating devices developed for 
indoor use such as, for example, those illustrated in U.S. Pat. No. 
4,659,077 to Stropkay and U.S. Pat. No. 4,434,981 to Norton. The devices 
disclosed in these two patents include a pair of foot support platforms 
adapted to guide the feet in a linear reciprocatory manner while 
independent hand manipulated means are provided for simulating movement of 
ski poles. In each device, however, there is no operative connection 
between the foot and hand movements, and for that reason, the devices have 
proven difficult to use. Due to the difficulty of coordinating the hand 
and foot movements, individuals will spend hours, and sometimes days, 
trying to learn how to use such an apparatus, and in many cases where the 
apparatus is located in a public exercise facility, the embarrassment will 
prevent an individual from continuing to use the apparatus. 
To avoid the shortcomings of the apparatus disclosed in the Stropkay and 
Norton patents, cross-country ski exercise devices have been developed 
wherein the movements of the feet and arms are coordinated by mechanical 
linkage so that as one foot moves rearwardly the associated hand moves 
forwardly. In fact, in some of these devices, foot supporting platforms 
themselves are mechanically linked so that as one foot moves rearwardly 
the other foot moves forwardly. Examples of such devices are shown in U.S. 
Pat. No. 4,679,786 issued to Rogers and Canadian Patent No. 490,720 issued 
to Denison. While the devices disclosed in these patents overcome the 
coordination problems inherent in the patents to Stropkay and Norton, it 
will be appreciated that the exercise motion provided by a device wherein 
the arms and legs are operatively interconnected for simultaneous movement 
at equivalent speeds, which is biochemically incorrect and awkward, will 
create a very jerky motion which is not necessarily enjoyable and is 
difficult to maintain over a long period of time. Further, the jerking 
movement might cause physiological damage which is not caused by the 
smooth fluid motion obtained in natural cross-country skiing. 
It was to overcome some of the shortcomings in the aforenoted prior art 
that the apparatus disclosed in U.S. Pat. No. 4,960,276 issued to Feuer et 
al. was developed. The Feuer patent is of common ownership with the 
present application. The Feuer apparatus includes means for allowing hand 
engaging members to move twice as fast a foot engaging supports so that 
relative movement between the hand engaging members and the foot engaging 
supports more closely resembles actual cross-country skiing. 
As will be appreciated from a review of the prior art, it can be seen that, 
in order to desirably simulate cross-country skiing, a fairly complex 
system needs to be employed which can include numerous gears, cables, fly 
wheels and the like. Some systems are so complex they are readily amenable 
to breakage or malfunction. Further, some systems have so many 
interconnected gears or the like that the internal resistance to operation 
renders them difficult to operate in a manner that provides merely light 
exercise. 
It is to overcome the shortcomings in the prior art devices and to produce 
a device that closely resembles cross-country skiing that the present 
invention has been developed. 
SUMMARY OF THE INVENTION 
The exercise apparatus of the present invention has been designed with 
simplicity in mind while providing an apparatus that closely resembles 
cross-country skiing, can be operated continuously over long periods of 
time and allows for variable resistance to permit very light to very heavy 
workouts. 
The basic framework for the apparatus consists of a plurality of 
longitudinally extending channel members that are interconnected by cross 
beams so as to define a horizontal platform on which an individual obtains 
the desired exercise. A pair of foot supporting members and a pair of hand 
engaging members are mounted for linear reciprocating movement within the 
channels defined by the frame members, and a control system interconnects 
the foot supporting members and hand engaging members to coordinate 
relative movement. In this manner, associated hands and feet can move in 
opposite directions with the hands moving at approximately twice the speed 
of the feet so as to accurately simulate cross-country skiing. 
The control system includes a main drive belt interconnecting the foot 
supporting members through a main drive pulley so that the foot supporting 
members move in opposite directions. A secondary belt or cable of fixed 
length is anchored at both ends to the frame and extends around a 
plurality of idler pulleys while being fixed to the hand engaging members 
and operably connected to the foot supporting members via an idler pulley. 
The secondary belt thereby allows the hand engaging members to move 
reciprocally at twice the speed of the foot supporting members as desired. 
The main drive pulley is operatively associated with a mechanical rectifier 
so as to transmit the reciprocal pivotal movement of the main drive pulley 
to unidirectional rotation of an output shaft of the rectifier. The output 
shaft is in turn connected via belt and pulley systems to a conventional 
flywheel and to a resistance system for variably and selectively 
restricting the pivotal movement of the main drive pulley. Restriction of 
the main drive pulley consequently restricts movement of the foot 
supporting members and hand engaging members which are operatively 
connected thereto. An electronic sensor is also utilized in conjunction 
with the resistance pulley to measure the rotational speed of the pulley 
thereby giving the user of the apparatus an indication of his hypothetical 
speed relative to the ground. 
The flywheel establishes an inertial system so that the apparatus does not 
place sudden stresses on the user's body. The resistance system permits 
the apparatus to simulate cross-country skiing from its lightest form of 
exercise, i.e. traversing a level terrain, to a more difficult exercise, 
i.e. movement up a hill. 
Other aspects, features and details of the present invention can be more 
completely understood by reference to the following detailed description 
of a preferred embodiment, taken in conjunction with the drawings and from 
the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The exercise apparatus 10 of the present invention is seen in FIG. 1 to 
include a base platform 12, an upright standard 14 at the forward end of 
the platform upon which an electronic control and display device 16 is 
positioned and an adjustable upright restraining system 18 at the rear end 
of the platform. The electronic control and display device 16 includes 
conventional state-of-the-art electronics for controlling the level of 
exercise desired from the apparatus and for displaying hypothetical ground 
speeds of operation of the apparatus as well as estimations of 
hypothetical distance covered and other such information. 
The upright restraining system 18 at the rear end of the platform has a 
substantially vertical segment 20 which is adjustable in length in a 
conventional manner and a horizontal segment 22 which is also adjustable 
in length. The terminal end of the horizontal segment 22 carries a 
vertically pivotal joint 24 to which a belt 26 is operatively connected 
with the belt being adapted to extend around the waist of a user of the 
apparatus. The vertical and horizontal adjustments are provided to 
accommodate various sized individuals so that when using the apparatus an 
individual is restrained and will not move forwardly in the apparatus. 
With reference to FIGS. 3, 4, 6, 7 and 8, the base platform 12 can be seen 
to include a framework of longitudinally extending channel extrusions 28 
and cross-frame members 30a, 30b, 30c, 30d, 30e and 30f interconnecting 
the extrusions in a desired spaced relationship. A cover sheet 32, FIG. 1, 
overlies the framework to enclose most of the working components of the 
apparatus. 
As probably best illustrated in FIG. 3, there are five longitudinally 
extending channel extrusion members 28 of three different cross-sectional 
configurations identified by reference numerals 28a, 28b and 28c. A 
central extrusion 28a has an upper plate 34 and a lower plate 36 which are 
interconnected by arcuate outwardly concave webs 38 which define outwardly 
opening channels 40 for a purpose to be described in more detail later. A 
pair of intermediate extrusions 28b are positioned adjacent to and in 
parallel relationship with the central extrusion 28a, and they also 
include an upper plate 42 and a lower plate 44. The lower plate 44 
includes raised ribs 46 along its lateral edges for a purpose to be 
described later. As with the central extrusion, the intermediate 
extrusions 28b have their upper and lower plates interconnected by arcuate 
outwardly concave webs 48 which define inwardly and outwardly opening 
channels 50. Outer side extrusions 28c are positioned adjacent to the 
intermediate extrusions 28b on the side opposite from the central 
extrusion 28a. The outer side extrusions include an upper plate 52 and a 
lower plate 54 with an arcuate and inwardly concave side web 56 
interconnecting the upper and lower plates. The web 56 in cooperation with 
the lower plate 54 defines an inwardly opening channel 58. The side web 
has a vertically extending skirt 60 forming a downward extension from the 
outermost side edge of the bottom plate. 
The cover sheet 32 previously mentioned in connection with the platform 12 
overlies the skeletal framework shown in FIG. 3, but has not been 
illustrated in FIG. 3 for clarity purposes. 
As best seen in FIGS. 3 and 5, the six longitudinally spaced cross beams 
30a, 30b, 30c, 30d, 30e and 30f interconnect the channel extrusions 28 
along their bottom plates and in a manner such that the channel extrusions 
extend longitudinally of the apparatus in slightly spaced relationship to 
each other so as to define four parallel longitudinally extending slots 62 
between adjacent edges of the upper plates. 
A pair of foot supporting members 64 which may be referred to as foot 
trolleys are adapted to roll within the confronting channels defined by 
the webs of the central and intermediate channel extrusions 28a and 28b, 
respectively. Each trolley 64 includes a base frame member 66 in which a 
pair of parallel laterally extending axles 68 are mounted with each axle 
having a pair of wheels 70 rotatably disposed on its ends. A neck portion 
72 of each base frame member 66 projects upwardly through a slot 62 and is 
integral with a platform 74 having a forwardly inclined upper surface. The 
platform 74 defines the support surface upon which an individual's feet 
are positioned and the forward incline has been found desirable in 
facilitating use of the apparatus. The base frame member 66 of each foot 
supporting trolley has a bracket 76 attached to the trailing end thereof 
which supports a horizontal idler pulley 78 for a purpose to be described 
in more detail hereinafter. The leading end of the base frame 66 for each 
foot supporting trolley has means for anchoring a timing belt 80 the 
purpose for which will become more clear with the description that 
follows. 
A pair of hand engaging members 82 which may be referred to as hand 
trolleys include simulated ski poles 84 which can be gripped by a user of 
the device. The poles are pivotally connected through a yoke and pin 
connector 86 to an integral base frame 88 of an associated trolley. The 
base frame 88 of the hand trolleys is of inverted U-shaped tubular 
configuration so that a belt 90 can be extended longitudinally 
therethrough while being fixedly attached to the trolley. The function of 
the belt will be described later. Each hand trolley has a pair of parallel 
transverse axles 92 carrying rotatable wheels 94 on opposite ends thereof 
with the wheels being adapted to ride within opposing channels of the 
intermediate extrusions 28b and the outer side extrusions 28c. The yoke in 
the yoke and pin connector 86 on each trolley extends upwardly from the 
base frame through the slot 62 between the intermediate extrusions 28b and 
the outer side extrusions 28c. The poles 84 themselves are adjustable in 
length to accommodate various height individuals. 
The upright restraining standard 18 is anchored to the base platform 12 by 
a shortened cross frame member 96 seen in FIG. 4. The shortened cross 
frame member is attached to the underside of the channel extrusions 28 but 
rearwardly of the area in which the foot supporting members 64 are 
reciprocated so that the standard does not interfere with the movement of 
the trolleys. This can be appreciated by reference to FIG. 1. 
A control system for interconnecting and coordinating the movement of the 
foot supporting members 64 and the hand engaging members 82 is shown best 
in FIGS. 4 and 5. With particular reference to FIG. 5, the timing belt 80 
is seen anchored at opposite ends to the front end of each foot supporting 
member 64. The timing belt extends around a horizontally disposed main 
drive pulley 98 at the front end of the apparatus 10 which is mounted for 
reciprocal pivotal movement on a vertical shaft 100. The shaft 100 is part 
of a mechanical rectifier 102 to be described later. A secondary belt or 
cable previously identified with reference 90, which may be a heavy cloth 
belt or any other substantially non-elastic belt, has opposite ends 
anchored at 104 in close proximity to each other to cross frame member 30e 
near but not at the rear end of the apparatus. The secondary belt 90 from 
its anchored locations extends forwardly around the idler pulleys 78 on 
the trailing ends of the foot supporting members before returning 
rearwardly to pass around inner idler pulleys 106 at the rear end of the 
apparatus 10 and subsequently laterally outwardly around second idler 
pulleys 108 at the rear end of the apparatus. The belt 90 makes right 
angle turns around the pulleys 108 before extending forwardly for right 
angle passage around idler pulleys 110 at opposite corners of the front 
end of the apparatus. Along the belt's extent toward the front idler 
pulleys 110, the secondary belt is fixed to the hand engaging members 82 
so that the members 82 move reciprocally in unison with the belt 90. The 
idler pulleys at the front and rear end of the apparatus, around which the 
secondary belt extends, are anchored to associated cross frame members 30a 
and 30e, respectively, in suitable bearings, not seen. 
It can be seen from the arrangement of the timing belt 80 and the secondary 
belt 90 that movement of either of the foot supporting members 64 along 
its associated slot 62 will cause the opposite foot supporting member to 
move in an opposite direction. Simultaneously, the hand engaging members 
82 are caused to move in an opposite direction to its adjacent foot 
supporting member. It will also be appreciated that the hand engaging 
members will move at a linear speed of twice that of the foot supporting 
members. 
The shaft 100 on which the main drive pulley 98 is mounted forms an input 
shaft to the mechanical rectifier 102 which is best seen in FIGS. 4 and 6. 
The output shaft 112 of the rectifier extends downwardly and carries 
stacked upper and lower pulleys 114 and 116, respectively. According to 
the inherent function of a mechanical rectifier, pivotal movement of the 
input shaft 100 on which the main drive pulley 98 is mounted causes a 
continuous unidirectional movement of the output shaft 112 and 
consequently each of the pulleys 114 and 116 which are fixedly mounted 
thereon. 
The pulley 116 on the output shaft of the rectifier is in alignment with a 
flywheel pulley 118 which is disposed rearwardly thereof relative to the 
length of the apparatus but in the same horizontal plane. The flywheel 
pulley is mounted on a shaft 120 via a conventional slip clutch (not seen) 
with the shaft 120 being anchored to and projecting downwardly from cross 
frame member 30c. A conventional flywheel 122 is also connected in a fixed 
manner to the shaft 120 so as to rotate in unison with the shaft. A 
flywheel belt 124 extends around pulley 116 and the flywheel pulley and is 
engaged by a tensioning pulley 126 (FIG. 7) which is mounted on a swivel 
arm 128 that is spring biased by a torsion spring 130 into engagement with 
the belt 124 to retain a desired tension in the belt. 
The upper pulley 114 on the output shaft 112 of the rectifier 102 is in 
horizontal alignment with a vertically disposed resistance pulley 132 
forming a part of a resistance system which includes a conventional 
infinitely variable electronic brake or adjustment component 134 for 
selectively and variably restricting the rotational movement of the 
resistance pulley 132. The resistance pulley is keyed to an output shaft 
136 of the electronic brake component 134, and a resistance pulley belt 
138 interconnects the resistance pulley 132 with the upper pulley 114 on 
the output shaft of the rectifier so that resistance to rotative movement 
of the resistance pulley by the electronic brake component can be 
transmitted to the output shaft of the rectifier 102 and consequently to 
the input shaft 100 of the rectifier on which the main drive pulley 98 is 
mounted. In this manner, the resistance to movement of the foot supporting 
members 64 and the hand engaging members 82 can be regulated by the 
electronic brake component which in turn can be controlled in a 
conventional manner from the electronic control and display device 16 
described previously. 
Also mounted on the output shaft 136 of the electronic brake component 134 
is a coded disc 140 which cooperates with a sensor 142 that detects 
rotative movement of the disc 140 and in combination with the electronic 
control and display device 16 converts that movement into information 
indicative of the speed of rotation of the disc. This information is 
conventionally converted to a digitized readout of a relative linear speed 
indicative of the hypothetical speed of movement which a user of the 
apparatus might have relative to the ground. The electronic brake 
component 134 and consequently the resistance pulley 132 and speed sensing 
disc 140 associated therewith are anchored to cross beam 30c near the 
front of the apparatus. 
With reference to FIG. 6, a cover plate 144 is suspended from cross frame 
members 30a and 30b at the front of the apparatus through bolts 146 and 
spacers 148 (FIG. 6) so as to cover some of the working components of the 
apparatus. The cover plate also has a bearing 150 mounted therein to 
receive the lower end of the output shaft 112 of the rectifier. One of the 
bolts connecting the cover plate to the cross frame members also serves as 
a pivotal shaft for the swivel arm 128 carrying the tensioning pulley 126 
and the associated torsion spring 130. 
In order to support the framework for the apparatus at a desired height, 
square tubular members 152 are welded to cross frame members 30a and 30f 
at the front and rear of the apparatus, respectively, to conventionally 
receive adjustable legs 154 as best illustrated in FIGS. 3 and 4. 
As is well known in the art, the flywheel 122 establishes inertia for the 
system which virtually eliminates any jerking motion in use of the 
apparatus. To assist in this regard, the slip clutch absorbs any sudden 
torque changes. As mentioned previously, such jerking motion undesirably 
stresses joints in the body which might cause physiological damage to a 
user of the apparatus. A further means for preventing damage of this type 
could be incorporated into the apparatus at the connection 104 of the 
secondary belt 90 to the framework. At this location, coil springs 156, 
FIG. 5, could be utilized to attach the end of the belt to the framework 
which would cushion the movement of the foot supporting members 64 and the 
hand engaging members 82. 
It will be noted from the description of the apparatus that it is 
relatively simple in construction, not only in the basic framework of the 
apparatus wherein the channel members 28 for guiding the trolleys also 
form structural components, but also in the control system. The simplicity 
of the control system enables a user of the apparatus to operate the 
apparatus with minimal resistance if desired to achieve a very light 
exercise. On the other hand, through use of the braking component 134 and 
the resistance belt 138 and pulley 132, the resistance to movement of the 
trolleys can give a user an unusually heavy exercise which might simulate 
uphill skiing. Safeguards to physiological damage have also been 
incorporated into the system in a simplified manner so that the apparatus 
is safe to use while providing any desired level of exercise over any 
desired period of time. 
In an alternative mode of operation, the ski poles 84 can be removed from 
the hand engaging members 82, and a user of the apparatus can merely grip 
a U-shaped handle 158 secured to the standard 14 at the front of the 
apparatus immediately beneath the electronic control and display system 
16. In this manner, the user would develop exercise of the lower torso but 
not the upper torso if this were either desired or dictated by an 
individual's condition. 
Although the present invention has been described with a certain degree of 
particularity, it is understood that the present disclosure has been made 
by way of example, and changes in detail or structure may be made without 
departing from the spirit of the invention, as defined in the appended 
claims.