BACKGROUND OF THE INVENTION The invention relates generally to a massaging device. More particularly, the present invention relates to an improved lie-down massager capable of efficiently treating bodily malfunctions such as back pain and gastrointestinal weakness by applying a therapeutic massaging treatment along the back and neck of a patient lying down on the massager whose massaging bumps move horizontally and vertically along the patient's spinal cord and neck while the vertical movement of the massaging bumps are actuated by a mechanism that translates nonlinear movement into linear movement.

Conventional bed or mat type massaging devices employ a spring mechanism for vertically moving massaging bumps. As disclosed U. S. Patent No. 6,454, 732, a spring mechanism allows the massaging bumps to gently move up and down. However, when it comes to therapeutic effects, the spring mechanism proves too soft to push up the massaging bumps when stronger pressure is required, because tension of springs applies equally to patients lying on the massaging device regardless of patient's requirements.

A demand is to adopt a reliable mechanism demonstrating a steady and robust therapeutic effects while stabilizing the vertical movement of the massaging bumps.

SUMMARY OF THE INVENTION The present invention is contrived to overcome the conventional disadvantages. Accordingly, an object of the

invention is to provide a lie-down massager that improves therapeutic effects by adopting a vertical movement mechanism that translates nonlinear movement into linear movement.

Another object is to stabilize the vertical movement of the massaging bumps, thereby enabling patients to receive a steady and robust massaging of the massaging bumps applied to and along their backs and necks.

A further object is to improve product reliability and customer satisfaction by mechanically stabilizing the vertical movement of the massaging bumps.

To achieve these and other objects, the lie-down massager according to the present invention includes a base frame having an elongated top panel, through which an elongated top opening is formed centrally and lengthwise, a rider provided below the elongated top panel of the base frame, a guide member movably engaged between the base frame and the rider so as to enable the rider to make a horizontally reciprocal movement relative to the base frame, a lifter having a top plate, a bottom plate, and a lifting device moving the top plate vertically relative to the bottom plate, massage bumps attached to the top plate of the lifter and moving vertically and/or horizontally along the elongated top opening of the elongated top panel of the base frame, and a pad covering the massage bumps and the elongated top opening of the base frame. The lifting device of the lifter translates nonlinear movement into linear movement.

The massage bumps are partitioned to first and second pairs. The first pair bumps are aligned parallel to the second pair bumps.

The lie-down massager further includes first and second bump holders propping and maintaining the first and second pair bumps above the top plate of the lifter, a first engagement member to rockingly engage the lower ends of the bump holders to the top plate of the lifter, and a second engagement member to rollingly engage the massage bumps thereto. The first and second bump holders are tapered toward each lower end thereof.

Preferably, the massage bumps are roller balls, and formed of jade. Each of the massage bumps includes a heater. The heater is a heating lamp generating heat and infrared rays.

The guide member includes one or more roller gear engaged to and powered by a roller gear motor, and one or more side rack gears parallel to each other and provided lengthwise in the base frame. The roller gear motor is fixed to the rider, and the roller gears are rollably connected to the rider and rotatably mounted on the side rack gears.

Alternatively, the guide member includes rider guide rollers provided on each side of the rider, and a pair of pulleys linked by a rope and respectively mounted in a front end portion and a rear end portion of the base frame. The rider guide rollers are rollably engaged to the base frame to guide a horizontally reciprocal movement of the rider. A predetermined portion of the rope is fixedly attached to the rider so that the pulley rotation enables the rider to generate a horizontally reciprocal movement of the rider. The pulleys are relatively twisted by 90 degrees against each other.

The lie-down massager may further include a pair of roller coasters parallel to each other, and coaster guide rollers formed outwardly extending from each side

of the lifter. The coaster guide rollers enable the lifter to make a roller coasting movement on and along the waved top surfaces of the roller coasters. The roller coasters are attached to the base frame. Each of the roller coasters has a substantially waved top surface.

Each of the waved top surfaces of the roller coasters substantially forms a curvature of a human spinal cord.

The lifter may further include a plurality of elongated guides extending downward from the bottom plate, and the rider further includes a plurality of guide bushes upwardly formed on the rider to releasably receive the elongated guides so as to stabilize the roller coasting movement of the lifter along the roller coasters.

The elongated guides, are shaped in pins.

According to the first embodiment of the present invention, the lifting device of the lifter includes a first link assembly and a lifter motor. The top plate has a top upper surface portion and a top lower surface portion, and the bottom plate has a bottom upper surface portion and a bottom lower surface portion. The first link assembly includes a gear shaft rotatably attached to the bottom plate, a link gear fixed to the gear shaft, a low link fixed to the gear shaft, and a high link connecting between the low link and the top plate. The lifter motor rotates the link gear of the first link assembly either clockwise or counterclockwise direction, so that the rotation of the link gear lifts or lowers the top plate. One or more lifter guides extend downward from the top lower surface portion of the top plate. One or more lifter guide bushes extend upward from the bottom upper surface portion of the bottom plate to releasably receive the lifter guides.

The lifter may further include a second link assembly. The second link assembly includes a gear shaft rotatably attached to the bottom plate, a link gear fixed to the gear shaft, a low link fixed to the gear shaft, and a high link connecting between the low link and the top plate. The link gear of the first link assembly and the link gear of the second link assembly engage with each other. The first link assembly and the second link assembly are positioned symmetrical with each other, so that when the lifter motor rotates the link gear of the first link assembly, the first link assembly and the second assembly lift or lower the top plate.

The link gears of the first and second link assemblies are spur gears, and the lifter motor includes a driving spur gear that engages with the link gear of the first link assembly.

The bottom plate of the lifter includes two bearing walls that extend upward from the bottom upper surface portion. The gear shafts of the first and second link assemblies are rotatably supported between the two bearing walls.

Each of the low links of the first and second link assemblies includes a low top end and a low bottom end that is fixed to the gear shaft. Each of the high links of the first and second link assemblies includes a high top end and a high bottom end that is rotatably attached to the low top end. Each of the first and second link assemblies further includes a link shaft that is rotatably attached between two guide flanges extending downward from the top lower surface portion of the top plate. The high top ends of the high links are rotatably attached to the link shafts.

According to the second embodiment of the present invention, the lifting device of the lifter includes one or more link assemblies, a screw shaft and a lifter motor. Each of the link assemblies includes one or more links and a nut block. The nut block engages with the screw shaft and the lifter motor rotates the screw shaft.

The screw shaft is rotatably attached to the bottom plate. Each of the links includes a top end that is rotatably attached to the top plate and a bottom end that is rotatably attached to the nut block, so that the link assembly moves the top plate up and down as the screw shaft is rotated by the lifter motor in either clockwise or counterclockwise direction. The top plate is surrounded by the bottom plate so that the top plate is guided by the bottom plate when the top plate is moved up and down.

The top plate includes a top slab, a top front wall, a top rear wall, and two top side walls. The two top side walls connect the top front wall and the top rear wall.

The top front wall, the top rear wall and the top side walls extend downward from the top slab. The bottom plate includes a bottom slab, and two bottom side walls that extend upward from the bottom slab. Each of the bottom side walls includes one or more guide flanges extend perpendicular from the bottom side wall. The top front wall, the top rear wall and the top side walls of the top plate are guided by the bottom side walls and guide flanges of the bottom plate when the top plate is moved up and down by the link assemblies.

The screw shaft is rotatably attached between the two bottom side walls of the bottom plate.

The link assembly further includes a link shaft rotatably fixed between the top front wall and the top

rear wall of the top plate. The top ends of the links of the link assembly are rotatably attached to the link shaft. The nut block includes two block ends to which the bottom ends of the links of the link assembly are rotatably attached, and a female thread portion that is provided between the block ends and engages with the screw shaft.

The nut block further includes two wheels rotatably attached on the block ends. The wheels roll on the bottom slab.

The lifter motor includes a worm gear attached thereto, and the screw shaft includes a worm wheel attached thereto and engages with the worm gear.

According to the third embodiment of the present invention, the lifter further includes elongated guides extend marginally from the top plate of the lifter. The elongated guides are releasably received by guide bushes formed on the bottom plate to stabilize a vertically reciprocal movement of the top plate relative to the bottom plate. The lifting device of the lifter includes a shaft rotatably engaged to the bottom plate. The shaft is eccentrically connected to a cam disk so that the shaft rotation generates an eccentric rotation of the cam disk.

The cam disk is defined by an inner disk section, an outer ring section, and ball bearings circularly provided between the inner disk section and the outer ring section.

An outer rim of the outer ring section abuts to the top plate of the lifter, so that the shaft rotating generates the vertically reciprocal movement of the top plate relative to the bottom plate in accordance with the eccentric rotation of the cam disk while the outer rim of the outer ring section of the cam disk oscillatingly abuts to the top plate of the lifter.

The cam disk is formed in pair. The elongated guides are shaped in pins. The lie-down massager further includes a motor having a motor shaft parallel to the cam shaft and a timing belt carried on the motor shaft and the cam shaft.

Advantages of the present inventions include that: (1) the lifting mechanism minimizes parts required for the vertical movement of the massaging, while improving stability in the vertical reciprocation of the lifter carrying the massaging bumps ; (2) the lifting mechanism provides smooth and quite operation of the lifter; (3) the coasting member working with the roller coasters to realize an additional lifting by utilizing the horizontally reciprocal movement of the, rider enables the massaging bumps to continue a smooth, steady and robust massaging on the patient, thereby substantially improving massaging effect and subsequently maximizing customer satisfaction ; (4) the cam-shaft mechanism adopted for the vertical movement of the massaging bumps stabilizes power transmission from the cam motor to the lifter while facilitating control of massaging strength, thereby improving therapeutic effects of the massager; and (5) the oscillating motion of the cam disk along the top plate of the lifter further accelerates massaging effects of the massage bumps that make a free rocking depending on the curvature of the bodily portion being massaged, thereby improving product reliability.

Although the present invention is briefly summarized, the full understanding of the invention can be obtained by the following drawings, detailed description and appended claims.

BRIEF DESCIPTION OF THE DRAWINGS These and other features, aspects and advantages of the present invention will become better understood with reference to the accompanying drawings, wherein: FIG. 1 is a view showing a lie-down massager with a patient lying thereon according to the present invention ; FIG. 2 is a plan view showing the lie-down massager without the patient in FIG. 1 ; FIG. 3 is a partial perspective view showing an overall mechanism of the lie-down massager ; FIG. 4 is a partial plan view showing the mechanism; FIG. 5 is a partial perspective view showing the mechanism according to the first embodiment of the present invention; FIG. 6 is a partial exploded perspective view showing a rider and a lifter; FIG. 7 is a perspective view of the lifter showing the operation of the gear-operated link mechanism ; FIG. 8 is a view similar to FIG. 7 but viewed from the opposite direction ; FIG. 9 is a plan view of. the lifter; FIG. 10 is a front elevation view showing that the lifter is in its lowest position; FIG. 11 is a front elevation view showing that the lifter is in its highest position; FIG. 12 is a partial exploded perspective view showing the mechanism according to the second embodiment of the present invention; FIG. 13 is a partial exploded perspective view showing the rider and the lifter ; FIG. 14 is a side elevation view of the lifter ; FIG. 15 is a front elevation view showing that the lifter is in its lowest position;

FIG. 16 is a front elevation view showing that the lifter is in its highest position ; FIG. 17 is a perspective view of the lifter with different massage bumps attached thereon; FIG. 18 is a perspective view of the lifter showing the screw-operated link lifting mechanism ; FIG. 19 is a view similar to FIG. 14 but with different massage bumps; FIG. 20 is a view similar to FIG. 15 but with different massage bumps ; FIG. 21 is a partial exploded perspective view showing the mechanism according to the third embodiment of the present invention; FIG. 22 is a partial view showing a cam mechanism of the lie-down massager according to the present invention; and FIGS. 23A-23D are views showing a cam-applied lifting mechanism of the lie-down massager according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a brief massaging mechanism of a lie- down massager 10 according to the present invention with a patient lying thereon for a bodily massage, and FIG. 2 shows a plan view of the massager 10 excluding the patient.

As shown therein, the lie-down massager 10 includes a base frame 12 in a bed type or a mat type. The base frame 12 includes an elongated top panel 14, and an elongated opening 16 is formed centrally and lengthwise through the elongated top panel 14. The massager 10 includes a rider 18 and a lifter 20. The rider 18 is

provided below the elongated top panel 14 of the base frame 12.

In order to implement the horizontal reciprocation of the rider 18, there is provided a guide member 26 movably engaged between the base frame 12 and the rider 18 so as to enable the rider 18 to make a horizontally reciprocal movement relative to the base frame 12. Here, it is recommended that the guide member 26 be either a rope-pulley application or a rack gear application.

As shown in FIG. 2 together with FIG. 3, the guide member 26 according to the rope-pulley application includes a rope 28, a pair of pulleys 30 and a pulley motor 32 that controls one of the pulleys 30. The pulleys 30 are linked by the rope 28 and respectively mounted in a front end portion 34 and a rear end portion 36 of the base frame 12. In a preferred version, the pulley motor 32 is provided adjacent to the pulley 30 provided in the rear end portion 36 of the base frame 12. In this construction, a predetermined portion 29 of the rope 28 is fixedly attached to the rider 18 so that the pulley rotation enables the rider 18 to generate a horizontally reciprocal movement of the rider 18. Preferably, the pulleys 30 are relatively twisted by 90 degrees against each other to facilitate the horizontal reciprocation of the rider 18 while improving controllability of the rider reciprocation.

Meanwhile, FIGS. 4,5 and 6 respectively illustrate the rack gear application for the horizontal reciprocation of the rider 18. As shown therein, the guide member 26 employing the rack gear application includes a pair of side rack gears 40 parallel to each other and lengthwisely provided in the base frame 12, a roller gear 42 perpendicular to the side rack gears 40,

and a roller gear motor 44 fixed to the rider to power the roller gear 42. The roller gear 42 is reliably connected to the rider 18 and rotatably mounted on the side rack gears 40. Here, a plurality of guider rollers 52 may be formed from each side of the rider 18 to further stabilize the horizontally reciprocal movement of the rider 18 along the rack gears 40.

To accelerate massaging effect, the massager 10 includes one or more pairs of roller coasters 50 parallel to each other. The roller coasters 50 are attached to the base frame 12 and above the rider guide rollers 52 formed on each side of the rider 18 (refer to FIG. 3). The rider guide rollers 52 are rollably engaged to the base frame 12 to guide a horizontally reciprocal movement of the rider 18. That is, the roller coasters 50 are formed on each side of the base frame 12. Here, the roller coasters 50 each have a substantially waved top surface 54. It is preferred that the waved top surfaces 54 of the roller coasters 50 each substantially form a curvature of a human spinal cord.

In order to utilize the roller coasters 50, there are provided two coaster guide rollers 90 formed outwardly extending from each side of the lifter 20. The coaster guide rollers 90 enable the lifter 20 to make a roller coasting movement on and along the waved top surfaces 54 of the roller coasters 50.

FIGS. 5-11 show the first embodiment of the present invention.

As shown in FIGS. 7-12, the lifter 20 has a top plate 120 and a bottom plate 122, and a lifting device 900 moving the top plate 120 vertically relative to the bottom plate 122. The lifting device 900 translates nonlinear movement into linear movement. The lifting

device 900 includes a first link assembly 160, and a lifter motor 128. The top plate 120 has a top upper surface portion 130 and a top lower surface portion 132 (refer to FIG. 10). The bottom plate 122 has a bottom upper surface portion 134 and a bottom lower surface portion 136.

As shown in FIGS. 9 and 10, the first link assembly 160 includes a gear shaft 162 rotatably attached to the bottom plate 122, a link gear 164 fixed to the gear shaft 162, a low link 166 fixed to the gear shaft 162, a high link 168 connecting between the low link 166 and the top plate 120. The lifter motor 128 rotates the link gear 164 either clockwise or counterclockwise direction, so that the rotation of the link gear 164 lifts or lowers the top plate 120 via the low link 166 and the high link 168.

Referring to FIG. 7, four lifter guides 170 extend downward from the top lower surface portion 132 of the top plate 120 at the four corners of the top plate 120.

Four lifter guide bushes 172 extend upward from the bottom upper surface portion 134 of the bottom plate 122 to releasably receive the lifter guides 170.

The lifting device 900 may further include a second link assembly 174 for balanced and more stabilized lifting and lowering operations. The second link assembly 174 includes a gear shaft 176 rotatably attached to the bottom plate 122, a link gear 178 fixed to the gear shaft 176, a low link 180 fixed to the gear shaft 176, a high link 182 connecting between the low link 180 and the top plate 120. The link gear 164 of the first link assembly 160 and the link gear 178 of the second link assembly 174 engage with each other so that when one rotates clockwise, the other rotates counterclockwise, and vice versa. The first link assembly 160 and the second link assembly 174

are positioned symmetrical with each other, as shown well in FIG. 10. Therefore, when the lifter motor 128 rotates the link gear 164 of the first link assembly 160, the first link assembly 160 and the second assembly 174 together lift or lower the top plate 120.

The link gears 164, 178 of the first and second link assemblies 160, 174 are spur gears having identical dimensions. The lifter motor 128 includes a driving spur gear 184 that engages with the link gear 164 of the first link assembly 160.

The bottom plate 122 of the lifter 20 includes two bearing walls 186, 188 that extend upward from the bottom upper surface portion 134 (refer to FIG. 9). The gear shafts 162,176 of the first and second link assemblies 160,174 are rotatably supported between the two bearing walls 186, 188.

Each of the low links 166,180 of the first and second link assemblies 160,174 includes a low top end 190 and a low bottom end 192 that is fixed to the gear shaft 162,176. Each of the high links 168,182 of the first and second link assemblies 160,174 includes a high top end 194 and a high bottom end 196. The high bottom end 196 is rotatably attached to the low top end 190.

Each of the first and second link assemblies 160, 174 further includes a link shaft 198 that is rotatably attached between two guide flanges 200 extending downward from the top lower surface portion 132 of the top plate 122. The high top ends 194 of the high links 182 are rotatably attached to the link shafts 198.

Elongated guides 62 downwardly extend from the bottom lower surface portion 136 of the lifter 20, and guide bushes 64 are upwardly formed on the rider 18 to releasably receive the elongated guides 62 so as to

stabilize the roller coasting movement of the lifter 20 along the roller coasters 50. Preferably, the elongated guides 62 are shaped in pins.

Two side coasting walls 156 extend downward from two opposing ends of the bottom plate 122, and the coaster guide rollers 90 are rotatably attached to the side coasting walls 156 (refer to FIG. 8).

In order to finally apply the gear-operated link lifting mechanism to a patient lying on the massager 10, there are provided massage bumps 100 attached to the top upper surface portion 130 of the lifter 20 and moving vertically and/or horizontally along the elongated top opening 16 of the elongated top panel 14 of the base frame 12. Optionally, a pad 17 may be provided to cover the massage bumps 100 and the elongated top opening 16 of the base frame 12.

FIG. 11 shows that the top plate 120 is in its uppermost position, that is, the massage bumps 100 are in their topmost position. FIG. 10 shows that the top plate 120 is in its lowermost position, that is, the massage bumps 100 are in their lowermost position.

The massage bumps 100 are preferably partitioned to first and second pairs 102,104 (refer to FIG. 7). Here, the first pair bumps 102 are aligned parallel to the second pair bumps 104. The massage bumps 100 each include a heater 106 which can be a heating lamp generating heat and infrared rays (refer to FIG. 11).

To further improve massaging effect, there are provided first and second bump holders 108,110 propping and maintaining the first and second pair bumps 102,104 above the top plate 120 of the lifter 20. For a better massaging result, the first and second bump holders 108, 110 are tapered toward each lower end 109 thereof, and a

first engagement member 112 to rockingly engage the lower ends 109 of the bump holders 108,110 to the top plate 120 of the lifter 20, and a second engagement member 116 to rollingly engage the massage bumps 100 thereto, are provided. The massage bumps 100 may be roller balls formed of precious stone such as jade. In FIG. 7, fixed massage bumps 202 are provided between the massage bumps 100.

The massage bumps 100 are directed to massage the back and neck of the patient lying on the top panel 14 of the base frame 12.

The engagement members 112,116 each may be a bolt, a roller, or other engagement tool. In this bump-holder mechanism, the bump holders 108,110 flexibly engaging the massage bumps 100 to the top plate 120 of the lifter 20 so that the massage bumps 100 rollingly massage the back and neck of the patient lying on the base frame 12 while evenly spreading the massaging power along the bodily portions being pushed up by the massage bumps 100.

That is, the rocking mechanism of the bump holders 108, 110 enables the massage bumps 100 to smoothly follow the curvature of a spinal cord of the patient lying on the base frame 12 while each of the massage bumps 100 evenly delivers the massaging power to the patient's bodily portions being massaged.

The spur gear engagement between the link gears 164, 178 and the sliding movement of the lifter guides 170 within the lifter guide bushes 172 provide smooth, fine and silent operation of lifting or lowering the top plate 120 and thus, the massage bumps 100.

FIGS. 12-20 show the second embodiment of the present invention.

As shown in FIG. 12, a lifter 320 has a top plate 420 and a bottom plate 422, and a lifting device 902 moving the top plate 420 vertically relative to the bottom plate 422. The lifting device 902 includes two link assemblies 58, a screw shaft 459 and a lifter motor 428. As is shown well in FIG. 18, each of the link assemblies 458 has two links 460 and a nut block 462. The nut block 462 engages with the screw shaft 459 and the lifter motor 428 rotates the screw shaft 459. The screw shaft 459 is rotatably attached to the bottom plate 422.

Each of the links 460 has a top end 464 that is rotatably attached to the top plate 420 and a bottom end 466 that is rotatably attached to the nut block 462, so that the link assemblies 458 move the top plate 420 up and down as the screw shaft 459 is rotated by the lifter motor 428 in either clockwise or counterclockwise direction. The top plate 420 is surrounded by the bottom plate 422 so that the top plate 420 is guided by the bottom plate 422 when the top plate 420 is moved up and down.

The top plate 420 has a top slab 468, a top front wall 470, a top rear wall 472, and two top side walls 474.

The two top side walls 474 connect the top front wall 470 and the top rear wall 472. The top front wall 470, the top rear wall 472 and the top side walls 474 extend downward from the top slab 468. The bottom plate 422 has a bottom slab 176, and two bottom side walls 478 that extend upward from the bottom slab 476. Each of the bottom side walls 478 has two guide flanges 480 extend perpendicular from the bottom side wall 478. The top front wall 470, the top rear wall 472 and the top side walls 474 of the top plate 420 are guided by the bottom side walls 478 and guide flanges 480 of the bottom plate

422 when the top plate 420 is moved up and down by the link assemblies 458.

The screw shaft 459 is rotatably attached between the two bottom side walls 478 of the bottom plate 422.

The link assembly 458 further has a link shaft 482 rotatably fixed between the top front wall 470 and the top rear wall 472 of the top plate. The top ends 464 of the links 460 of the link assembly 458 are rotatably attached to the link shaft 482.

The nut block 462 has two block ends 484 to which the bottom ends 466 of the links 460 of the link assembly 458 are rotatably attached, and a female thread portion 486 that is provided between the block ends 466 and engages with the screw shaft 459. The nut block 462 further has two wheels 488 rotatably attached on the block ends 466. The wheels 488 roll on the bottom slab 176.

The lifter motor 428 has a worm gear 490 attached thereto, and the screw shaft has a worm wheel 492 attached thereto and engages with the worm gear 490.

Elongated guides 362 downwardly extend from the bottom slab 476 of the lifter 320, and guide bushes 64 are upwardly formed on the rider 18 to releasably receive the elongated guides 362 so as to stabilize the roller coasting movement of the lifter 320 along the roller coasters 50. Preferably, the elongated guides 362 are shaped in pins.

With the thread engagement between the screw shaft 459 and the nut block 462, and the link 460 transferring the horizontal movement of the nut block 462 into vertical movement of the link shaft 482, and thus of the top plate 420, balanced and stabilized lifting and lowering operations of the top plate 420 is provided.

Two coasting side walls 456 extend downward from two opposing ends of the bottom slab 476, and the coaster guide rollers 390 are rotatably attached to the coasting side walls 456.

In order to finally apply the screw lifting mechanism to a patient lying on the massager 10, there are provided six massage bumps 98 attached on the top slab 468 of the lifter 320 (refer to FIG. 12) and moving vertically and/or horizontally along the elongated top opening 16 of the elongated top panel 14 of the base frame 12.

The massage bumps 98 are round projections that are fixed on the top slab 468 of the lifter 320.

FIG. 19 shows that the top plate 420 is in its uppermost position, that is, the massage bumps 100 are in their topmost position. FIG. 20 shows that the top plate 420 is in its lowermost position, that is, the massage bumps 100 are in their lowermost position.

FIGS. 21-23A-D show the third embodiment of the present invention.

As shown therein, a lifter 620 has a top plate 622 and a bottom plate 624 and a lifting device 904 moving the top plate 622 vertically relative to the bottom plate 624.

In this construction, elongated guides 628 extend marginally from the top plate 622 of the lifter 620. The elongated guides 628 are releasably received by guide bushes 630 formed on the bottom plate 624 so as to stabilize a vertically reciprocal movement of the top plate 622 relative to the bottom plate 624. In a better version, the elongated guides 628 are formed in pins and the guide bushes 630 are formed in pin-receiving bushes.

As further shown in FIG. 22, the lifting device 904 includes a shaft 650 rotatably engaged to the bottom plate 624 and a cam disk 652. The shaft 650 is eccentrically connected to the cam disk 652 so that the shaft rotation generates an eccentric rotation of the cam disk 652. The cam disk 652 is defined by an inner disk section 654, an outer ring section 656, and ball bearings 658. The ball bearings 658 are circularly provided between the inner disk section 654 and the outer ring section 656. Here, an outer rim 657 of the outer ring section 656 abuts to the top plate 622 of the lifter 620.

FIGS. 23A-23D sequentially illustrate the cam- applied lifting mechanism of the lifter 620 in accordance with the rotation of the shaft 650. As shown therein, the rotation of the shaft 650 further generates the vertically reciprocal movement of the top plate 622 relative to the bottom plate 624 in accordance with the eccentric rotation of the cam disk 652 while the outer rim 657 of the outer ring section 656 of the cam disk 652 oscillatingly abuts to the top plate 622 of the lifter 620. Preferably, the cam disk 652 may be formed in pair to further stabilize the vertical reciprocal movement of the lifter 620. In order to rotate the shaft 650, a cam motor 660 having a motor shaft 662 may be provided so that the motor shaft 662 is parallel to the cam shaft 650.

Here, a timing belt 664 is carried on the motor shaft 662 and the cam shaft 650 to improve efficiency of the lifting mechanism.

An advantage of the lie-down massager 10 is that the cam-shaft mechanism adopted for the vertical movement of the massaging bumps 100 stabilizes power transmission from the cam motor 660 to the lifter 620 while

facilitating control of massaging strength, thereby improving therapeutic effects of the massager 10. Another advantage is that the oscillating motion of the cam disk 652 along the top plate of the lifter 620 further accelerates massaging effects of the massage bumps 100 that make a free rocking depending on the curvature of the bodily portion being massaged, thereby improving product reliability.

Although the invention has been described in considerable detail, other versions are possible by converting the aforementioned construction. Therefore, the scope of the invention shall not be limited by the specification specified above and the appended claims.