JP4339905B2 - Suspension device for body training device - Google Patents

Description

The present invention relates to a physical training device, and more particularly to a treadmill for physical training, and more particularly to a suspension device that supports a deck of a treadmill above a lying frame structure.

Treadmills for physical training are widely used in recreational facilities, sports clubs, and individual homes, and can walk, jog, and run indoors. Treadmills are particularly useful when the weather is bad or at night or in other cases where the athlete does not want to run outdoors. Many treadmills have a first roller assembly and a second roller assembly provided orthogonally at both ends of the frame. An endless belt is wound around the roller assembly. The upper traveling portion of the belt is supported by a lying deck located between the belt and the frame.

Conventionally, various efforts have been made to reduce the impact on a user's legs and indirectly when jogging or running on a treadmill. One method for reducing the impact on an exerciser's body is disclosed in US Pat. Nos. 4,974,831 and 4,984,810. In the treadmills disclosed in these patents, the rear end portion of the deck is rotatably attached to the frame, and the front end portion of the deck is supported by the suspension device. In the '831 patent, the suspension device consists of a fairly complex lever arm device and a cooperating shock absorber. The stride on the deck rotates the lever arm and extends the shock absorber, thereby attenuating the impact on the user's foot. The disadvantage of this shock absorber is its own complexity, which increases the manufacturing cost.

In the '810 patent, the front end of the dreadmill deck is supported by a shock absorber separate from the conventional compression spring. Placing the spring and shock absorber at the forefront of the deck imposes a non-negligible bending stress on the deck.

In other conventional treadmills, a rubber block is disposed between the deck and the lying frame to absorb the impact. Such a conventional treadmill is disclosed in French Patent No. 2,616,132. The dreadmill deck is positioned above the frame member and provided on the plurality of flexible pads. Bushes are inserted above and below each pad, and bolts hanging downward from the deck and bolts extending upward from the frame are received by the corresponding bushes. The bolt absorbs shock by placing a flexible pad between the deck and the frame.

U.S. Pat. Nos. 5,336,144 and 5,454,772 disclose decks supported above the frame by a plurality of cup-shaped elastomeric springs. The elastomer spring deforms reversibly when the deck bends downward relative to the frame. The elastomer spring has a side wall having a tapered thickness. As a result, the resistance to downward movement of the deck by the elastomer spring is proportional to the degree of deflection of the deck relative to the frame. One drawback of such a treadmill is that the elastomeric springs are fixed in place, each determining a smaller bearing area.

An object of the present invention is to improve the suspension structure of a conventional treadmill for body training as described above.

In order to achieve the above object, a treadmill adopted by the present invention includes a frame, a first roller assembly and a second roller assembly attached to the frame, and a winding around the first and second roller assemblies. An endless belt, a deck disposed between the frame and the upper running portion of the endless belt, and having a first end and a second end, and a load applied to the deck by the athlete At least one elongate spring that absorbs the elongate spring , wherein the spring rate is selectively changeable, and the elongate spring includes a hollow body portion extending in the length direction; And a compressible insertion member configured to a size and shape that can be selectively inserted into the hollow portion of the spring to the extent desired . In one aspect, a pivot connection is provided for pivotally coupling the second end of the deck to the frame. A long elastomer spring member is disposed between the frame and the deck between the first end and the second end of the deck, and is provided above the frame with a gap therebetween. Supporting the deck. When the exerciser steps on the endless belt, the elastomer spring member deforms reversibly while resisting bending (downward movement) of the deck with respect to the frame. The resistance provided by the elastomeric spring member is proportional to the degree of deflection of the deck.

In another aspect of the invention, the elastomeric spring member is provided between the frame side rails and below the deck side edges.

In another aspect of the present invention, the elastomer spring has a base portion and a bulging body extending upward from the base portion. The main body is formed in a hemispherical shape or a convex shape, and has a shape that bulges outward at the top. The inside of the elastomer spring between the base portion and the main body portion is hollow or partially hollow. As a result, the main body portion is bent downward by the force exerted on the deck by the exerciser.

Furthermore, in another aspect of the present invention, the thickness of the main body portion of the elastomer spring is larger at the connection portion with the base portion. The thickness of the main body portion is configured to become thinner as the distance from the base portion increases, and is thinnest at the top of the hemispherical main body portion. As a result, when the deck imposes a downward load on the elastomer spring, the central portion of the top of the main body deflects downward into the hollow interior. In the present invention, the lateral deformation that may occur when the elastomer spring is peeled does not occur. Also, the resistance imposed on the deck by the elastomer springs increases as the deck deforms downward, thus providing a variable spring rate.

In another aspect of the invention, the spring is configured such that the deformation rate can be selectively changed. In this connection, the shape and dimensions of the compressible insert are determined so that they can be selectively inserted into the desired extent of the spring cavity. In the cross section, the insertion member corresponds to the cross-sectional shape of the hollow portion of the spring. The spring may be tapered in the length direction. In another aspect, the body of the spring is configured to receive a compressible fluid as a bag. Specifically, the compressible fluid is air, and the air is supplied to the bag body by an air pump. A valve or other means is also provided for discharging compressible fluid from the bag.

In yet another aspect of the present invention, the pivotal connection of the rear end of the deck has a spindle that is attached to a side member of the frame and connected to a hinge bracket provided on the underside of the deck. With this configuration, the rear end of the deck is mounted so as to be rotatable with respect to the frame about an axis extending perpendicular to the length of the deck.

In FIG. 1, a treadmill 10 constructed according to the present invention has a frame 12, and a front roller assembly 14 and a rear roller assembly 16 are provided on the frame 12 so as to cross the frame 12. In the present specification, the front means a direction in which the exerciser heads when using the treadmill. “Front” and “rear” are used to mean opposite directions. An endless belt 18 is wound between the front roller assembly 14 and the rear roller assembly 16. A deck 20 is provided between the upper traveling portion of the belt 18 and the frame 12.

As shown in FIGS. 2, 3, and 5, the rear portion of the deck 20 is pivotally attached to the frame by a pivot connection 24, and the shaft on which the rear portion of the deck extends with respect to the length of the deck. Can be rotated so as to be orthogonal to the frame. An elongated, deformable spring 26 is provided on the frame and lies under the side edge of the deck to support the deck along with the pivot connection 24.

The frame 12 includes a pair of elongated side rails 30a and 30b. The side rails 30a and 30b include the rear side member 32, the intermediate side member 34, The front side lateral members 36 are arranged in parallel to each other at intervals in the lateral direction. Preferably, the cross member is formed from a hollow metal extruded material, so that a high strength with respect to the weight ratio can be obtained. A plurality of brackets 38 are disposed on the side rails 30a and 30b, and are engaged with the end portions of the roller bodies 14 and 16 as shown in FIGS.

Further, the frame 12 has a pair of flat mounting plates 40a and 40b which are located between the intermediate lateral member 34 and the front lateral member 36 and extend upwardly upward, and upward. The extending post 40 is supported. The post 40 extends upward and forward from the front end of the frame 12, and supports the lateral portion 42 of the handrail 44. The handrail 44 extends rearward and slightly downward from the lateral portion 42 and extends downward, and the extended end portion is attached to the frame by a mounting bracket 46. The handrail is grasped by a hand when an athlete walks, jogs or runs on the treadmill 10.

The post 40 also supports a display panel 41. The display panel displays various information during use of the treadmill, such as the speed of the belt, the length of exercise, the calorie consumption, and the course of exercise. The Typically, the display panel is provided with various control knobs or buttons such as a start button, speed control, and emergency stop.

The treadmill 10 further includes a motor 50, and a drive shaft 52 of the motor is connected to a drive belt 54 provided on one end side of the front roller assembly 14. The motor 50 rotatably drives the front roller assembly 14 to move the treadmill belt 18 so that an athlete strides over the belt. The motor 50 is disposed in a housing cover 56 that extends across the front of the treadmill.

2 to 4, the side rails 30 a and 30 b are configured as mirror images, and it is understood that the portions denoted by the same reference numerals are the same type portions. As shown in FIG. 4, the side rails 30a and 30b are made of a metal extruded material having a plurality of hollow portions, and have an outer portion 60 and an inner portion 62, and these portions are generally raised. The extension wall 64 is shared. In the cross section, the outer part 60 and the inner part 62 together form a closed box part, but the outer part 60 has a slightly more complicated shape than the inner part 62. The outer portion 60 has an outer wall 66 that is curved to project outward, and the outer wall 66 extends downward from the upper lip 68 toward the lower horizontal wall 70. Located between the upper lip 68 and the lower horizontal wall 70, the outer wall has an inwardly extending groove 72, which has an inlet 74 that is slightly narrower than the height of the groove itself. Yes. The groove 72 is sized to slidably receive an inner key portion (not shown) of the bracket 46 that attaches the lower end portion of the handrail 44 to the side rail of the frame.

With further reference to FIG. 4, the inner portion 62 has a substantially horizontal upper wall 76, a substantially vertical inner wall 78, and a substantially horizontal lower wall 80. They cooperate with the common wall 64 to determine a closed, substantially rectangular box-shaped cross section. As shown in FIG. 3, the rear lateral member 32 supports the bottom of the lower wall 80. Further, the lower edge of the intermediate transverse member 34 is substantially flush with the upper wall 76. As shown in FIGS. 2 and 3, the bracket 38 used for mounting the front roller assembly 14 and the rear roller assembly 16 is disposed on the upper wall 76, and the upper wall 76 serves as a shoulder. Function. Further, a long elastomer spring 26 is mounted on the upper wall 76. The side rails 30a and 30b are not limited to those shown in the drawings, and other configurations can be adopted without departing from the spirit of the present invention.

2 and 3, the deck 20 is formed of a flat, square and sufficiently strong panel, and the panel has a smooth upper surface and lower surface. Suitable materials for forming the deck include plywood, other reinforcing plate structures, reinforced heat-set plastic materials, metals, and other members with sufficient strength. Preferably, the strength of the deck is such that the value of EI [elastic modulus (lb / in ² ) × moment of inertia (in ⁴ )] is approximately in the range of 0.5 × 10 ⁶ to 2.0 × 10 ⁶ lbin ² . Preferably, the upper surface of the deck is coated or embedded with a low friction coating such as a wax composite.

As shown in FIG. 5, a trim stripe 84 is formed on each side edge of the deck to protect the end portion of the deck and restrain the belt 20 in the lateral direction. The trim stripe 84 has an upper portion 86 that overlaps the upper side edge of the deck, a side portion 88 that supports the side edge of the deck, and a lower shoulder 90 that overlaps the lower end portion of the deck. Preferably, the trim stripe 84 is formed from an extruded metal member or a plastic material.

Further, referring to FIG. 5, the pivot connection 24 is located at each end of the rear part of the deck so that the rear part of the deck is attached to the inner part 62 of the side rail of the frame. It has two hinge assemblies so that it can rotate about an orthogonal axis 94. More particularly, each hinge assembly has a mounting spindle 96 that is secured to the inner surface of the frame wall 78. A flange bearing 98 is provided on the reduced diameter shoulder portion formed at the end of the spindle 96, and the web portion of the flange bearing is mounted in a circular opening formed at a lower portion of the vertical leg portion 102 of the hinge bracket 104. ing. The hinge bracket 104 has a horizontal upper mounting plate portion 106, which is provided with a clearance opening, and extends through the deck to the hardware member 108 below the plate portion 106. The screw member to be connected is received.

The means for rotatably mounting the rear portion of the deck 20 with respect to the frame 12 may be other means. For example, a piano hinge (not shown) may be placed under the deck 20 and attached to a frame horizontal member (not shown).

In particular, in FIG. 4, the spring 26 is shown as having a generally “d” cross-sectional shape. The spring 26 has a base portion 112 lying on the upper frame wall 76 and a bulging upward projecting shape, and has a convex or dome-shaped main body portion 114. FIGS. As shown, the main body 114 extends upward from the base portion and supports the side edge of the deck 20 from below. The interior 116 of the spring 26 is preferably hollow or substantially hollow, allowing the body portion 114 to be deformed downward. Preferably, the body 114 is not formed from a uniform thickness, but rather is configured such that the thickness decreases as it moves away from the base 112, and the thickness of the top of the dome of the body 114 is the base 112. It is made to become the thickness of about 1/3 to 1/2 of the thickness of the main body in the connection part.

The performance of the spring 26 can be changed by changing its cross-sectional dimension. Increasing the overall cross-sectional dimension of the spring 26 and the size of the spring 26 can provide a stiffer spring, or decreasing the size can provide a less stiff spring. Further, the performance of the spring can be changed or altered by changing the thickness at various parts of the main body.

In one preferred embodiment, the spring width is about 1.0 to 1.5 inches and the thickness of the base 112 is about 0.2 to 0.4 inches. The overall height of the spring is about 1 to 1.25 inches. Furthermore, the thickness of the main body is 0.3 to 0.4 inches at the connection portion with the base, and the thickness decreases upward, and the thickness of the top of the main body is about 0.1. To 0.2 inches. In addition, these dimensions are only examples and do not limit the scope of the present invention.

Preferably, the spring 26 is made of an elastomer material such as natural rubber or a synthetic rubber compound. It is also possible to change the spring rate and other performance of the spring 26 by changing the strength of the rubber. The spring 26 is also formed to a length selected according to the degree to counter the downward deformation of the spring.

In addition, the spring 26 is disposed at a selected portion along the length of the side rails 30a and 30b so that the deck 26 can react to the impact load imposed by the athlete. Preferably, the springs 26 are disposed along the side rails so that they coincide with the site where the athlete's feet strike the belt on the deck 20.

The position of the spring 26 is held by a long piece 120 extending through a long groove formed in the base portion 112 of the spring. Both ends of the long piece 120 protrude from both ends of the elastomer spring to form a tab having clearance perforations, and extend downward through the tab to the inside of the rail wall 76. A screw member is received. It should be noted that other means may be adopted as means for attaching the spring 26 to the frame rail.

As described above, by selectively positioning and arranging the spring 26 along the length of the frame rail, the energy absorption and the traction effect obtained by the elastomer spring can be changed. This can be done by simply loosening the screw member 122 and reconnecting the screw member 122 into the wall 76 at different positions along the frame rail.

Although the spring 26 is illustrated as being mounted on the frame side rail, it may be mounted on the lower surface side of the deck 20 instead. For example, it can be performed by connecting the screw member 122 upward in the lower surface of the deck 20.

The spring 26 may be configured to slide along the frame rail. For example, as shown in FIG. 6, this can be achieved by forming the upper wall 76 'of the frame rail in an upward groove 130 to receive the spring 26'. 6 that are the same as those in FIG. 1 to FIG. 5 are given the same reference numerals, but are marked with a prime code “′”. Any suitable means may be employed to maintain the position of the spring 26 'in the length direction of the groove 130.

When the treadmill according to the present invention is used, when the athlete's feet are placed on the belt 18, the deck bends (moves) downward toward the frame 12. This deflection is counteracted by the compression of the spring 26. The spring 26 functions to absorb the impact of the athlete's foot. Since the deck of the treadmill is rotatably mounted at the rear part thereof and the other parts are supported only by the springs, the deck 20 can freely move up and down (rotate) with respect to the frame 12. it can. The downward deflection of the deck 20 towards the frame 12 results in reversible compression of the spring 26. In particular, the center of the top of the spring main body 114 has a smaller thickness than the portion where the main body is connected to the base 112, so that the center first deforms downward. However, as the deck 20 continues to move downward toward the frame 12, the portion of the main body 114 that gradually becomes thicker is also compressed and deformed. Thus, the spring 26 becomes progressively stiffer with further compression, providing a degree of resistance to downward movement of the deck 20 that increases in proportion to the range of movement of the deck 20.

Further, the main body 114 of the elastic spring is thinnest at the top of the main body. As a result, the main body 114 does not deform laterally when deforming (in this case, a lateral load will be applied to the deck 20), but its central portion is directed downward. It is designed to deform. This tendency to deform laterally or laterally can be prevented by forming the main body 114 gradually thinner from the base 112 toward the top of the bulge.

Since the degree of resistance to the downward movement of the deck 20 provided by the spring 26 is proportional to the deflection or downward movement of the deck, the treadmill 10 provides adequate shock absorption for any weight athlete. To do. Lighter weight athletes do not apply much impact to the treadmill when they step down. However, the treadmill deck 20 is deformed downward toward the frame due to the compression of the initial spring 26 ', which is relatively easy to obtain, so that adequate shock absorption can be provided even for relatively light individuals. it can. When a heavier individual uses the treadmill, a greater impact is applied to the deck 20, but this load is borne by the resistance of the spring 26, which increases as the downward deformation of the deck 20 increases. become.

The embodiment of the present invention shown in FIGS. 7 and 8 relates to a spring assembly 132 composed of a bulged or hollow spring 26 ″ configured similar to the springs 26 and 26 ′. The spring assembly 132 includes an insert member 134 that is shaped and dimensioned to be received within the hollow interior 116 '' of the spring 26 ''. Preferably, although not necessarily so, the outer shape of the insertion member 134 generally corresponds to the shape of the hollow interior 116 '' of the spring 26 ''. Also, ideally, the length of the insertion member 134 is a length corresponding to an important part of the length of the hollow interior 116 '' of the spring 26 ''. The spring 26 ″ and the insertion member 134 cooperate to form the spring assembly 132 to support the deck 20.

The purpose of the insertion member 134 is to change the performance of the spring assembly 132. For this reason, the insertion member 134 can be composed of a member similar to or different from the member forming the spring 26 ″. For example, the insertion member 134 is made of a hard material, a soft material, a more elastic material, or a more inelastic material with respect to the material constituting the spring 26. Further, the material of the insertion member may be peeled, hollow, or partially hollow, corresponding to the rigidity and flexibility desired for constituting the insertion member. By selecting a particular material compound or configuration of the insert member 134, the desired overall performance of the spring assembly 132 is obtained in cooperation with the spring 26 ''.

In addition to the material from which the insert member 134 is constructed, the performance of the spring assembly 132 can also be altered by changing the extent to which the insert member 134 is linked within the spring 26 ''. As shown in FIG. 7, the insertion member 134 is preferably selectively linked within the spring 26 ″ by the actuator device 136 and detached from the outside of the spring 26 ″. The actuator device 136 includes a power actuator 138, and the actuator 138 passes through an end wall 140 adjacent to the insertion member 134 and is connected to the connection shaft 142. Various types of actuators 138 are employed, for example, linear push-pull actuators such as fluid cylinders and magnetic coil assemblies. Alternatively, for example, the actuator 138 may be a rotary type driven by an electric rotary motor. In this example, the connecting shaft 142 is a lead screw that is screwed into the end wall 140. The actuator 138 may be remotely operated by the user through a control button or other interface device provided on the display panel 41.

Further, as shown in FIG. 7, the insertion member 134 is tapered in the length direction, and a different gap 144 is formed between the top of the insertion member 134 and the lower surface of the spring 26 ″. . This configuration allows the spring 26 '' to be deformed downward at a particular spring rate, which increases when the top wall of the spring 26 '' is sufficiently deformed to abut the top of the insert 134. become. According to this configuration, the spring assembly 132 initially provides a relatively low level of resistance to the downward movement of the deck 20 ″ and once the spring 26 ″ is sufficiently deformed to eliminate the gap 144, the deck Providing a relatively high level of resistance to further downward movement of the.

Another embodiment of the present invention is shown in FIGS. 9 to 11, in which the spring 26 '' 'is formed in an upward groove formed in the upper wall 76' '' of the frame rail. A fluid bag formed to a size acceptable within 130 '' '. As shown in FIG. 9, the bag body 26 '' 'is pressed against the lower surface of the deck 20' '', thereby supporting the deck. The bag has an elliptical cross-sectional shape, but may have another cross-sectional shape such as a circle, square, or rectangle.

A compressible fluid, such as air, is supplied to the bag body 26 '' '' via a supply hose 150 connected to an inlet formed in the bag body 26 '' '. When air is used as the compressible fluid, an air compressor 154 is employed as a supply source. The compressible fluid is discharged out of the bag body 26 '' 'through a discharge valve 156 in fluid communication with the bag body. Also, the valve 156 may be in fluid communication with the supply hose 150 or may be incorporated into the configuration of the compressor 154. The stiffness of the bag body 26 ′ ″ depends on the pressure of the compressible fluid, and this pressure can be remotely controlled by push buttons 158 and 160 disposed on the display panel 41.

Instead of using the two bag bodies 26 '' 'provided on the side rails of the frame, one bag body 26' '' provided on the transverse member 162 of the frame may be employed as shown in FIG. The transverse member is stationary with respect to the frame or can be adjusted in the length direction of the frame, and the position supported by the bag body 26 '' 'is set in the length direction of the deck 20' ''. You may make it changeable. Note that the bag body 26 ′ ″ may be replaced with a spring assembly 132 mounted on the transverse member 162.

As described above or illustrated, the springs 26, 26 ', 26 ", 26'" are formed in an elongated shape, and the spring is positioned between the frame and the deck, so that there is sufficient space between the spring and the deck. The length or area of the interface can be acquired, and holding stress or contact stress can be reduced or minimized. At the same time, since it is not necessary to increase the height in the vertical direction, the installation of the spring can be performed well and easily. Also, the spring according to the present invention has a small number of parts, which leads to manufacturing, assembly, installation, management and reliability.

It is a perspective view of the treadmill for body training concerning the present invention. It is a disassembled perspective view which shows the flame | frame, deck, rotational connection, and elastic spring of the treadmill shown in FIG. FIG. 2 is a cross-sectional view showing a part of the treadmill shown in FIG. 1. It is the fragmentary perspective view which expanded and showed the frame of the treadmill in the site | part of an elastic spring. In particular, it is a partially enlarged perspective view showing the rotational connection between the deck and the frame. It is a partial expanded sectional view concerning other embodiments. It is an expansion elevation view concerning other embodiments. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. It is an expansion elevation view concerning other embodiments. It is sectional drawing shown along the 10-10 line in FIG. It is a disassembled perspective view which concerns on other embodiment.

Explanation of symbols

10 Treadmill 14 Roller assembly 16 Roller assembly 18 Endless belt 20 Deck 24 Rotating connection 26 Long spring

Claims (33)

(A) a frame;
(B) a first roller assembly and a second roller assembly mounted to the frame;
(C) an endless belt wound around the first and second roller assemblies;
(D) a deck disposed between the frame and the upper running portion of the endless belt, and having a first end portion and a second end portion;
(E) At least one long spring adapted to absorb the load applied to the deck by the athlete , the spring rate being selectively changeable, and a hollow extending in the length direction A long spring having a main body , and
(F) A treadmill for body training characterized by having a compressible insertion member configured to have a size and shape that can be selectively inserted into the hollow main body portion of the spring to a desired degree . 2. The treadmill according to claim 1 , wherein the spring has a base part integrally formed with the hollow main body part and means for attaching the base part to the frame. The treadmill according to claim 1, wherein the cross-sectional shape of the insertion member substantially corresponds to the cross-sectional shape of the hollow main body portion of the spring. In any one of claims 1 to 3, treadmill, wherein the insert is tapered in the longitudinal direction. 5. The treadmill according to claim 1 , further comprising means for changing a range of connection of the insertion members in the spring. In any one of claims 1 to 5, treadmill, wherein the insertion member is formed from an elastomeric member. In any one of Claims 1 thru | or 6 ,
The hollow body is configured to receive a compressible fluid, and further includes means for supplying a compressible fluid to the hollow body and means for removing the compressible fluid from the hollow body. A treadmill characterized by 8. The treadmill according to claim 7, wherein the compressible fluid is air, and has an air pump for introducing air into the hollow main body . 9. The treadmill according to claim 7 , wherein the frame has a recess for receiving the hollow main body . (A) a frame;
(B) a first roller assembly and a second roller assembly mounted to the frame;
(C) an endless belt wound around the first and second roller assemblies;
(D) a deck disposed between the frame and the upper running portion of the endless belt, and having a first end portion and a second end portion;
(E) a pivot connection that pivotally connects the second end of the deck to the frame so as to rotate about an axis generally perpendicular to the length of the deck;
(F) At least one disposed between the frame and the deck between the first end and the second end of the deck so as to absorb a load applied to the deck by the athlete. Two springs, the springs being composed of an elastomeric material configured to selectively change the spring rate of the springs to absorb the load applied to the deck by the athlete. Treadmill. The treadmill according to claim 10, wherein the spring is disposed between the frame and the lower side of the deck. 12. The treadmill according to claim 10, wherein the spring is formed in a long shape and is disposed substantially in the length direction of the deck. 12. The treadmill according to claim 10, wherein the spring is formed in an elongated shape and is disposed substantially orthogonal to the length direction of the deck. 11. The treadmill according to claim 10, wherein the frame has a pair of side rails spaced apart in the lateral direction, and the spring is disposed between each side rail and the deck. 15. A treadmill according to claim 14, wherein the spring is disposed between the side rail and the lower side of the deck. The treadmill according to claim 15, wherein the spring is formed in a long shape and is disposed in a length direction of the side rail. 16. The treadmill according to claim 15, wherein the frame has at least one cross member crossing between the side rails, and the spring is disposed between the cross member and the lower side of the deck. 18. The treadmill according to claim 17, wherein the spring is formed in an elongated shape and is disposed in the length direction of the transverse member. 11. A treadmill according to claim 10, wherein the spring provides resistance to movement of the deck relative to the frame under the load imposed by the exerciser in proportion to the extent to which the deck moves toward the frame. The treadmill according to claim 10, wherein the spring rate increases with deformation of the spring. The treadmill according to claim 10, wherein the spring is reversibly deformable under a load applied to the deck by the athlete. The treadmill according to claim 21, wherein the deformation range of the spring in the unit load imposed by the deck becomes smaller as the load imposed on the elastomer spring increases. The treadmill according to claim 10, wherein the spring includes a hollow main body portion extending in a length direction. 24. A treadmill according to claim 23 , comprising a compressible insertion member configured to a size and shape that can be selectively inserted into the hollow body of the spring to a desired degree. 25. The treadmill according to claim 24 , wherein the spring has a base portion configured integrally with the hollow main body portion, and means for attaching the base portion to the frame. 25. The treadmill according to claim 24, wherein a cross-sectional shape of the insertion member substantially corresponds to a cross-sectional shape of the hollow main body portion of the spring. 27. The treadmill according to claim 24, wherein the insertion member is tapered in the length direction. The treadmill according to claim 24 , further comprising means for changing a range of connection of the insertion members in the spring. 25. The treadmill according to claim 24, wherein the insertion member is formed of an elastomer member. 24. The hollow body portion according to claim 23 , wherein the hollow body portion is configured to receive a compressible fluid, and further, means for supplying a compressible fluid to the hollow body portion and removing the compressible fluid from the hollow body portion. And a treadmill. 31. The treadmill according to claim 30, wherein the compressible fluid is air and has an air pump for introducing air into the hollow main body . 32. The treadmill according to claim 30 , wherein the frame has a recess for receiving the hollow main body . 33. The deck of any one of claims 10 to 32, wherein the deck has an EI value of 0.5 × 10 ⁶ to 2.0 × 10 ⁶ lb. A treadmill characterized by having a strength in the range of in ² .

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