GAS BAGS FOR MASSAGING DEVICE

Abstract

A gas bag for a massaging device is taught that preferably includes a bellows-shaped portion that is capable elongating and contracting by air supply and air discharge. The gas bag is formed from a thermoplastic resin. The gas bag is annealed while the bellows-shaped portion is compressed so as to have a length shorter than a natural length at the time of molding thereof.

Description

This application claims priority to Japanese patent application serial number 2006-266964, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to gas bags for a massaging device (which will be hereinafter simply referred to as “gas bags”). More particularly, the present invention relates to gas bags that can be used in massaging chairs, massaging beds, vehicle seats having a massaging function or other such devices.

A pneumatic massage chair is already known. Conventionally, such a massaging chair having a plurality of gas bags (massaging elements) that are embedded therein. Each of the gas bags may preferably be inflated and deflated (elongated and contracted) by air supply and air discharge, so as to push or massage a user sitting in the chair. Generally, the massaging chair may preferably be covered by a covering member. Therefore, the gas bag, when inflated or elongated, may preferably project from a surface of the chair while pushing up the covering member, so as to push the user with interleaving the covering member. Further, the gas bag, when deflated or contracted, may preferably be retracted in the chair, so as to not project from the surface of the chair.

Such a gas bag is taught, for example, by Japanese Laid-Open Utility Model Publication No. 7-333.

The known gas bag is generally formed from a widely used plastic (e.g., polyethylene). Also, the gas bag is shaped as a corrugated or bellows-shaped cylindrical hollow member. The bellows-shaped gas bag can be easily elongated and contracted between an elongated condition and a contracted (normal) condition, so as to easily have a elongating and contracting distance (stroke). Generally, it is preferable that the gas bag may have an increased stroke in order to improve a massaging effect. However, if the bellows-shaped portion of the gas bag is elongated beyond an elastic region thereof in order to increase the stroke of the bas bag, the gas bag may possibly be no longer returned to the contracted condition due to plastic deformation that can be produced in the bellows-shaped portion thereof. Therefore, various approaches have been made in order to increase the stroke of the bas bag without elongating the bellows-shaped portion of the gas bag beyond the elastic region thereof. For example, the shape of the bellows-shaped portion of the gas bag has been variously changed. Alternatively, the gas bag has been formed from a highly-elastic plastic (i.e., a plastic having high elastic limit).

Generally, the bellows-shaped portion of the gas bag is repeatedly elongated and contracted in order to provide a massaging function for the user. Therefore, the gas bag must be formed from highly-durable materials. In addition, in recent years, a massaging seat in which the gas bag is embedded therein has been used as a vehicle seat. As will be appreciated, the vehicle seat may be inherently exposed to high temperatures. Therefore, the gas bag used in the vehicle seat must be formed from heat-stable materials.

BRIEF SUMMARY OF THE INVENTION

Thus, there is a need in the art for an improved gas bag that can be used in massaging devices, e.g., as massaging chairs, massaging beds and vehicle massaging seats.

For example, in one embodiment of the present invention, a gas bag for a massaging device may include a bellows-shaped portion that is capable elongating and contracting by air supply and air discharge. The gas bag is formed from a thermoplastic resin. The gas bag is annealed while the bellows-shaped portion is compressed so as to have a length shorter than a natural length at the time of molding thereof.

According to this embodiment, the gas bag is annealed while the bellows-shaped portion is compressed. Therefore, when the gas bag is in a contracted condition, the bellows-shaped portion of the gas bag may preferably have a length shorter than the length of a bellows-shaped portion of an unannealed gas bag. As a result, the gas bag may have an increased elongating and contracting distance (stroke). In addition, because the gas bag is annealed, the bellows-shaped portion of the gas bag may have an increased elastic range. The increased elastic range may contribute to increase of the stroke of the gas bag.

The gas bag may be formed from a thermoplastic crystalline resin. The gas bag formed from the thermoplastic crystalline resin may have increased restorability. Therefore, the gas bag can be reliably restored to an original length when it is contracted.

Also, the gas bag may be formed from a thermoplastic crystalline elastomer. The gas bag formed from the thermoplastic crystalline elastomer may have increased durability or flexibility. Therefore, the gas bag (the bellows-shaped portion) is not be easily broken even if the gas bag is repeatedly elongated and contracted. This may lead to a prolonged working life.

Further, the gas bag may be formed from a thermoplastic polyester elastomer. The thermoplastic polyester elastomer has good heat stability. Therefore, the gas bag formed from the thermoplastic polyester elastomer may preferably be used at high temperatures.

Other objects, features, and advantages, of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a gas bag according to a representative embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along line 1′-11 in FIG. 1;

FIG. 3 is a transparent perspective view of a vehicle seat having a plurality of gas bag;

FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3;

FIG. 5 is a graph illustrating relationship of a time versus a contracted length of the gas bag when the gas bag is continuously operated at a high temperature.

DETAILED DESCRIPTION OF THE INVENTION

In the following, a detailed representative embodiment of the present invention will be described with reference to FIG. 1 to FIG. 5. As shown in FIGS. 1 and 2, a gas bag 10 has a hollow bag-shape. The gas bag 10 includes a barrel portion or bellows-shaped portion 12. One axial end of the bellows-shaped portion 12 is closed and has a pressing surface 14. Conversely, the other axial end of the bellows-shaped portion 12 is provided with a gas supply-discharge port 16. The bellows-shaped portion 12 of the gas bag 10 may preferably be inflated and deflated (elongated and contracted) when gas is supplied to and discharged from the gas bag 10 via the supply-discharge port 16, so that the gas bag 10 can be axially inflated and deflated (elongated and contracted).

FIGS. 3 and 4 shows a vehicle seat 30 having a massaging unit. The massaging unit is composed of a base member 20 and a plurality of (eight in this embodiment) gas bags 10 that are attached to the base member 20. The massaging unit thus constructed is embedded in a seat back 32 of the seat 30, so that the gas bags 10 can press or massage shoulders, a back and a lower back of a user (passenger) sitting in the seat 30 when the gas bags 10 are axially elongated and contracted. As best shown in FIG. 4, the gas bags 10 are respectively received in through holes that are formed in a cushion pad 34 of the seat back 32. Further, as shown in FIG. 4, the gas bags 10 are appropriately positioned such that the pressing surfaces 14 thereof are substantially flush with an outer surface of the cushion pad 34, when the gas bags 10 are in a contracted condition (original or normal condition). In other words, the gas bags 10 are appropriately positioned such that the pressing surfaces 14 thereof contact (or are slightly spaced away from) a covering member 36 of the seat back 32.

An air pump (not shown) is connected to the supply-discharge ports 16 (not shown in FIG. 4) of the gas bags 10 via hoses 18, so that gas (air) can be supplied to and discharged from the gas bags 10, thereby inflating and deflating the gas bags 10. In particular, when gas is supplied to the gas bags 10, the gas bags 10 are elongated while pushing up the cover 36, thereby pressing the user via the covering member 36. To the contrary, when gas is discharged from the gas bags 10, the gas bags 10 are contracted, so that the pressing operation of the user can be released or diminished. Thus, the gas bags 10 can massage the user.

Each of the gas bags 10 of the present invention may preferably be formed from a thermoplastic resin. In particular, the gas bag 10 may preferably be manufactured by molding the thermoplastic resin (a molding step) and then annealing the molded resin (an annealing step). First, in the molding step, the thermoplastic resin is molded by blow molding or other such known molding methods, thereby forming an intermediate gas bag (an untreated gas bag) having a bellows-shaped portion. The bellows-shaped portion of the intermediate gas bag thus formed may have a predetermined height or length, which length is referred to as an original or natural (axial) length. Next, in the annealing step, the intermediate gas bag is annealed (subjected to annealing) while the bellows-shaped portion thereof is compressed so as to have a length shorter than the natural length, thereby producing a final gas bag (a treated gas bag) having a compressed bellows-shaped portion. The bellows-shaped portion of the final gas bag thus produced may have a predetermined height or length, which length is referred to as an original or compressed natural (axial) length. As will be appreciated, the final gas bag may preferably be used as the gas bag 10.

In particular, in the annealing process, the intermediate gas bag is heated to a temperature closer to a melting point of the thermoplastic resin while compressing the bellows-shaped portion thereof. Thereafter, the heated intermediate gas bag is slowly cooled. As a result, the intermediate gas bag can be reshaped and sustained while the bellows-shaped portion thereof is compressed, thereby forming the final gas bag. Therefore, the length (the compressed natural length) of the bellows-shaped portion of the final gas bag may preferably be shorter than the length (the natural length) of the bellows-shaped portion of the intermediate gas bag. As a result, the final gas bag may have an elongating and contracting distance (stroke) greater than the intermediate gas bag. In addition, the bellows-shaped portion of the final gas bag may have an increased elastic range. This is attributed to the fact that the thermoplastic resin is physically modified by annealing. The increased elastic range may further increase the stroke of the final gas bag.

The gas bag 10 of the present invention can be formed from various thermoplastic resins. However, the gas bag 10 may preferably be formed from a thermoplastic crystalline resin having a molecular structure that contains a crystallized region therein. Examples of the thermoplastic crystalline resin may include commonly used plastic materials such as polypropylene, polyamide, polyacetal and polyester. The thermoplastic crystalline resin may have increased restorability by annealing. It is considered that the thermoplastic crystalline resin, when annealed, may preferably be modified, so that the crystallized region thereof may have increased crystallinity, thereby increasing restorability of the whole resin. Therefore, according to such a crystalline resin, the gas bag 10 having increased restorability can be formed. Therefore, the gas bag 10 formed from the crystalline resin, when contracted, can be reliably restored to an original length even after the gas bag 10 is repeatedly elongated and contracted. As a result, the stroke of the gas bag 10 can substantially be maintained constant over a long period of time. This may lead to stabilized massaging function of the gas bag 10. In addition, due to the increased restorability, the gas bag 10, when contracted, can be reliably retracted in the through holes formed in the cushion pad 34 of the seat back 32 without pushing the covering member 36 (FIG. 4). Therefore, the seat 30 may have a good appearance and a comfortable ride over a long period of time.

More preferably, the gas bag 10 may be formed from a thermoplastic crystalline elastomer having a molecular structure that contains a crystallized region therein. The thermoplastic crystalline elastomer is composed of a hard segment and a soft segment. The thermoplastic crystalline elastomer has good durability or flexibility because the soft segment thereof has inherently high flexing properties. Therefore, the gas bag 10 formed from the thermoplastic crystalline elastomer may have good durability or flexibility. As a result, the gas bag 10 (the bellows-shaped portion) may not be easily damaged even if the gas bag 10 is repeatedly elongated and contracted many times.

In particular, the thermoplastic crystalline elastomer may preferably be a thermoplastic polyester elastomer. The thermoplastic polyester elastomer is composed of polyester (the hard segment) and polyether (the soft segment). The thermoplastic polyester elastomer has good heat stability in addition to the increased restorability and flexibility. Therefore, the gas bag 10 formed from the thermoplastic polyester elastomer may have good heat stability. As a result, the gas bag 10 can be used at high temperatures, for example, 100° C. or less. Therefore, the gas bag 10 formed from the thermoplastic polyester elastomer may preferably be used in the vehicle seat 30, which is possibly exposed to high temperatures, for example, 80° C.

The following example shows that the present gas bag has more excellent properties than the properties of the prior art (untreated or unannealed) gas bag. Further, the following example is illustrative and should not be construed as a limitation of the invention.

EXAMPLE

In order to evaluate some properties of the present gas bag, a plurality of different gas bags (Gas Bags A, A′, B, B′, Z and Z′) were prepared.

Gas Bags A and A′:

A thermoplastic polyester elastomer (TPEE) (“PELPRENE” (registered trademark) manufactured by TOYOBO CO., LTD.) was molded by blow molding, thereby forming an intermediate gas bag (an untreated gas bag), which will be referred to as Gas Bag A′. Gas Bag A′ thus formed had a length (a natural length) h of 44.3 mm. Thereafter, Gas Bag A′ thus formed was annealed at 165±8° C. while the bellows-shaped portion thereof is compressed so as to have a length of 22 mm shorter than the natural length h (44.3 mm) thereof. Thereafter, heated Gas Bag A′ was slowly cooled, thereby producing a final gas bag (a treated gas bag), which will be referred to as Gas Bag A. Gas Bag A thus produced had a length (a compressed natural length) H of 22 mm. Dimensions of Gas Bags A′ and A are shown in Table 1. Further, references φ, I, R and H(h), described in Table 1 respectively correspond to a diameter of the gas bag, a width or length of a ridge of the bellows-shaped portion of the gas bag, a radius of curvature of the ridge, and a height or length of the gas bag, which references are referred to in FIG. 2.

Gas Bags B and B′:

Similar to Gas Bags A′ and A, TPEE was molded by blow molding, thereby forming an intermediate gas bag (an untreated gas bag) dimensionally different from Gas Bag A′, which will be referred to as Gas Bag B′. Gas Bag B′ thus formed had a length (a natural length) h of 61.9 mm. Thereafter, Gas Bag B′ thus formed was annealed at 165±8° C. while the bellows-shaped portion thereof is compressed so as to have a length of 19 mm shorter than the natural length h (61.9 mm) thereof. Thereafter, heated Gas Bag B′ was slowly cooled, thereby producing a final gas bag (a treated gas bag), which will be referred to as Gas Bag B. Gas Bag B thus produced had a length (a compressed natural length) H of 19 mm. Dimensions of Gas Bags B′ and B are shown in Table 1.

Gas Bags Z and Z′:

A polyethylene resin (PE) was molded by blow molding, thereby forming an intermediate gas bag (an untreated gas bag) similar to Gas Bag A′, which will be referred to as Gas Bag Z′. Gas Bag Z′ thus formed had a length (a natural length) h of 44.3 mm. Further, Gas Bag Z′ thus formed corresponds to the known gas bag. Thereafter, Gas Bag Z′ was annealed while the bellows-shaped portion thereof is compressed so as to have a length of 22 mm shorter than the natural length h (44.3 mm) thereof. Thereafter, heated Gas Bag Z′ was slowly cooled, thereby producing a final gas bag (a treated gas bag), which will be referred to as Gas Bag Z. Gas Bag Z thus produced had a length (a compressed natural length) H of 22 mm. Dimensions of Gas Bags Z′ and Z are shown in Table 1.

	TABLE 1
	Dimension
		φ	I	R	H	h
	Material	(mm)	(mm)	(mm)	(mm)	(mm)
Gas Bag A	PTEE	60	Not Measured	Not Measured	22	—
Gas Bag A′ (Control)	PTEE	60	5.8	1.3	—	44.3
Gas Bag B	PTEE	60	Not Measured	Not Measured	19	—
Gas Bag B′ (Control)	PTEE	60	5.8	1.3	—	61.9
Gas Bag Z	PE	60	Not Measured	Not Measured	22	—
Gas Bag Z′ (Control)	PE	60	5.8	1.3	—	44.3

(Evaluation for Properties of the Gas Bags)

First, in a room heated to a high temperature of 80° C., the gas bags were continuously operated (i.e., elongated and contracted) by supplying and discharging air thereinto. The gas bags were elongated and contracted at a rate of 10 times per minute for fifteen (15) hours. In the operation, with regard to Gas Bags A and A′ and Gas Bags Z and Z′, supplied air was controlled such that they constantly have a length (an elongated length) of 100 mm in an elongated condition. Conversely, with regard to Gas Bags B′ and B, supplied air was controlled such that they constantly have a length (an elongated length) of 70 mm in an elongated condition.

During the operation, air supplies were stopped every hour, so that the gas bags were contracted to a contracted condition. In the contracted condition, a length (a contracted length) of each of the gas bags was measured. The measured contracted length of each of the gas bags after 15 hours is shown in Table 2. Further, change in time of the contracted length of Gas Bag A is shown in FIG. 5. In addition, upon completion of the operation (i.e, after 15 hours), a stroke of each of the gas bags was calculated by subtracting “the measured contracted length after 15 hours” from “the elongated length (100 mm or 70 mm).” The data is shown in Table 2.

	TABLE 2
			Contracted	Stroke
	Original	Elongated	Length	After 15
	Length	Length	After 15 Hours	Hours
	(mm)	(mm)	(mm)	(mm)
Gas Bag A	22	100	50	50
Gas Bag A′ (Control)	44.3	100	95	5
Gas Bag B	19	70	44	26
Gas Bag B′ (Control)	61.9	70	85	—
Gas Bag Z	22	100	90	10
Gas Bag Z′ (Control)	44.3	100	115	—

As shown in Table 2, after 15 hours, Gas Bag A has the contracted length of 50 mm and the stroke of 50 mm. However, the Gas Bag A′ has the contracted length of 95 mm and the stroke of 5 mm. Also, Gas Bag B has the contracted length of 44 mm and the stroke of 26 mm. However, Gas Bag B′ has the contracted length of 85 mm that is longer than the elongated length (70 mm) thereof. This is considered to be a phenomenon that is caused by creep buckling of the material. These results demonstrate that the gas bag formed form TPEE and annealed under compression may have increased restorability even if it is operated at high temperatures. Therefore, the annealed TPFE gas bag may have a desired stroke.

Further, as shown in FIG. 5, the contracted length of Gas Bag A is gradually increased from the original or natural length (i.e., 22 mm) to about 50 mm over the first hour and is then maintained at substantially a constant value (i.e., about 50 mm). This demonstrates that the gas bag formed form TPEE and annealed under compression may have increased restorability over a long period of time.

In addition, as shown in Table 2, after 15 hours, Gas Bag Z has the contracted length of 90 mm and the stroke of 10 mm. However, similar to Gas Bag B′, Gas Bag Z′ has the contracted length of 115 mm that is longer than the elongated length (100 mm) thereof. This is also considered to be a phenomenon that is caused by creep buckling. These results demonstrate that the gas bag formed form PE and annealed under compression may have considerable restorability even if it is operated at high temperatures. Therefore, the annealed PE gas bag may also have a desired stroke. However, the stroke (10 mm) of Gas Bag Z is smaller than the stroke (50 mm or 26 mm) of Gas Bags A and B. This means that the annealed PE gas bag may have a restorability smaller than the annealed TPEE gas bag.

Next, in a room at normal temperature, the gas bags were continuously operated (i.e., elongated and contracted) by supplying and discharging air thereinto. In this test, supplied air was controlled so as to have a pressure of 77 kPa.

During the operation, each of the gas bags was visually observed, so as to determine occurrence of cracks in the bellows-shaped portion thereof. From the observation, with regard to each of Gas Bags A and B, no crack was produced in the bellows-shaped portion thereof even after it was elongated and contracted 2,500,000 times. Conversely, with regard to Gas Bag Z, some cracks was produced in the bellows-shaped portion thereof when it was elongated and contracted 400,000 times. The results demonstrate that the annealed TPEE gas bag may have a durability or flexibility greater than the annealed PE gas bag. This means that the annealed TPEE gas bag may have a prolonged working life compared with the annealed PE gas bag.

A representative example of the present invention has been described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present invention and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the foregoing detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe detailed representative examples of the invention. Moreover, the various features taught in this specification may be combined in ways that are not specifically enumerated in order to obtain additional useful embodiments of the present invention.

Claims

1. A gas bag for a massaging device, comprising:

a bellows-shaped portion that is capable of elongating and contracting by air supply and air discharge,

wherein the gas bag is formed from a thermoplastic resin, and wherein the gas bag is annealed while the bellows-shaped portion is compressed so as to have a length shorter than a natural length at the time of molding thereof.

2. The gas bag as defined in claim 1, wherein the thermoplastic resin comprises a thermoplastic crystalline resin having a molecular structure that contains a crystallized region therein.

3. The gas bag as defined in claim 1, wherein the thermoplastic resin comprises a thermoplastic crystalline elastomer.

4. The gas bag as defined in claim 1, wherein the thermoplastic resin comprises a thermoplastic polyester elastomer.

5. The gas bag as defined in claim 1, wherein the gas bag is constructed to be applicable to a vehicle seat.