The present invention provides a method of manufacturing calcium phosphate powder comprising the steps of preparing a mixed material by mixing calcium hydroxide (Ca(OH)2) powder and calcium hydrogenphosphate powder so that a molar ratio (Ca/P) of calcium to phosphor is set to a range of 1.45-1.72; conducting a mixing/milling treatment to the mixed material to cause a soft-mechanochemical compositing reaction thereby to prepare a calcium phosphate precursor; and conducting a heat treatment to thus obtained precursor at a temperature of 600xc2x0 C. or more thereby to prepare calcium phosphate powder. According to the present invention, the manufacturing process is simple and the manufacturing cost can be remarkably reduced. In addition, fine calcium phosphate powder excellent in characteristics can be easily manufactured in a short time.

The present invention relates to a method of manufacturing calcium phosphate powders such as xcex2-tricalcium phosphate and hydroxy calcium phosphate or the like that are suitable for biomaterials, and more particularly relates to a method of manufacturing the calcium phosphate powders that are capable of easily manufacturing the calcium phosphate powders having an excellent characteristics through a simple manufacturing process, and capable of greatly reducing a manufacturing cost of the calcium phosphates.
Calcium phosphates typically represented by xcex2-tricalcium phosphate [Ca3(PO4)2] and hydroxy calcium phosphate (hydroxy apatite) [Ca10(PO4)6(OH)2] are excellent in suitability to organism structure and have an affinity to organism body, so that calcium phosphates are valuable as bio-ceramic raw materials for constituting artificial bone, artificial tooth, artificial articulate or the like. In addition, calcium phosphates have been widely utilized as materials such as base material for tooth paste, additive for medical product, food additives, material for cosmetic chemist, separating/absorbing material for biopolymer and material for constituting humidity sensor or the like.
Conventionally, these calcium phosphate powders have been manufactured in accordance with the following methods such as wet-way (liquid phase) synthesizing method, dry-way (solid phase) synthesizing method, mechanochemical-reaction synthesizing method or the like. The wet-type synthesizing method is a synthesizing methodin which a calcium solution of calcium nitrate or the like is reacted with a phosphoric acid solution of ammonium hydrogen phosphate, or an amorphous calcium phosphate is produced from a reaction being taken place in heterogeneous system comprising calcium hydroxide and phosphoric acid, then the formed amorphous calcium phosphate is subjected to a calcining treatment thereby to produce xcex2-tricalcium phosphate (xcex2-TCP).
On the other hand, the dry-type synthesizing method is a method in which calcium carbonate is reacted with calcium pyrophosphate in a solid phase at a high temperature thereby to obtain calcium phosphate powder.
On the other hand, in these years, there has been also proposed a manufacturing method comprising simple manufacturing process and utilizing the mechanochemical reaction as a new method of synthesizing the calcium phosphate compound. For example, a publication of examined Japanese Patent Application No. HEI3-69844 and a publication of unexamined Japanese Patent Application No. HEI4-321508 disclose a method in which calcium carbonate powder and calcium hydrogenphosphate powder or dihydrate thereof are mixed to prepare a slurry of which molar ratio (Ca/P) of calcium to phosphor is controlled, then thus obtained slurry is milled by using a ball mill or a vibration mill or the like to cause reaction, thereafter, the reaction product is dried and heat-treated at a high temperature thereby to manufacture crystallized xcex2-tricalcium phosphate (xcex2-TCP).
Further, a publication of unexamined Japanese Patent Application No. HEI4-321508 discloses a method in which xcex2-tricalcium phosphate is heated under a condition of existing water and pressingly treated thereby to manufacture hydroxy calcium phosphate (hydroxy apatite) powder. In this connection, in the conventional process of manufacturing the hydroxy calcium phosphate, a process directly using the mechanochemical reaction has not been adopted.
However, in case of the conventional wet-type synthesizing method, the synthesizing conditions such as the molar ratio of a raw material, treating speed, pH or the like are required to be strictly controlled. On the other hand, there is a difficulty in obtaining a product having a compositional high purity and uniformity. At any rate, for the purpose of obtaining a powder having a compositional high-purity and uniformity, there is posed a problem that the manufacturing cost would be greatly increased.
In contrast, in case of the conventional dry-type synthesizing method, the synthesized calcium phosphate powder has a coarse grain size, so that the powder cannot be directly used as a bio-ceramics raw material and a fine grinding or milling treatment is essentially required whereby there is posed a problem that the manufacturing process becomes complicate and troublesome.
On the other hand, in case of the conventional synthesizing method utilizing the mechanochemical react ion, a long-term grinding process for 1 day to 50 hours is essentially required for advancing the reaction, thereby to cause a problem that the production cost is greatly increased. In addition, in order to smoothly advance the reaction, a solid content of the slurry is required to be set to a lower level. Therefore, there are posed various problems such that an amount of heat energy to be put into the subsequent drying process remarkably increases, a drying operation is required to perform for a long time. In addition, for the purpose of pulverizing or grinding the coarsely aggregated bodies caused by the drying operation, an additional grinding process is essentially required, so that there is posed a fatal problem such that a running cost for the manufacturing facilities and the production cost are greatly increased.
The present invention had been achieved to solve the aforementioned problems and an object of the present invention is to provide a method of manufacturing calcium phosphate powder, the method being capable of easily manufacturing fine calcium phosphate powder having excellent characteristics by a simple manufacturing process and capable of greatly reducing the production cost of the powder.
In order to achieve the aforementioned object, the inventors of the present invention had prepared calcium phosphate powders under various conditions by using various material powders, reacting synthesizing methods and pulverizing devices (grinding machines). Then, through many experiments, the inventors had comparatively reviewed the influences of the differences in the manufacturing conditions onto characteristics and manufacturing cost of calcium phosphate powder as a product.
As a result, the inventors had found and obtained the following knowledge. That is, when calcium hydroxide powder as a raw material is used in place of the conventional calcium carbonate, then the calcium hydroxide powder is mixed to calcium hydrogen phosphate powder thereby to prepare a mixed material, then the mixed material is further mixed and milled to take place a mechanochemical reaction. Thereafter, when the reaction product is heat-treated, there can be obtained knowledge that fine particles of calcium phosphate compound having a high crystallinity and high homogeneity can be effectively manufactured in a short time.
In particular, when a multi-ring media type ultrafine mill comprising a number of ring-shaped milling media is used as a mixing and milling device for advancing a mechanochemical reaction by conducting the mixing and the milling of the mixed material, there could be also obtained the findings such that a reaction activity of the mixed material was increased, and it became possible to rapidly advance the above mechanochemical reaction whereby a production efficiency of the calcium phosphate compound could be remarkably increased.
Furthermore, in the conventional various synthesizing methods conducted in a wet, the solid component content (viscosity) of the mixed material slurry required to be suppressed to a lower level, and the mixed material slurry is required to be mixed and pulverized for a long time. In contrast, when the above ultrafine mill is used, even if the slurry has a high solid content and a high viscosity, there could be also obtained a finding that it becomes possible to mix and pulverize the slurry in a short time whereby the production efficiency of the calcium phosphate compound could be remarkably increased.
The present invention had been achieved on the basis of the above findings. Namely, a method of manufacturing calcium phosphate powder according to the present invention comprises the steps of preparing a mixed material by mixing calcium hydroxide (Ca((OH)2) powder and calcium hydrogenphosphate powder so that a molar ratio (Ca/P) of calcium to phosphor is set to a range of 1.45-1.72; conducting a mixing/milling treatment to the mixed material to cause a soft-mechanochemical compositing reaction thereby to prepare a calcium phosphate precursor; conducting a heat treatment to thus obtained precursor at a temperature of 600xc2x0 C. or more thereby to prepare a calcium phosphate powder.
In the above method, it is preferable that the calcium hydrogenphosphate is at least one compound selected from the group consisting of calcium monohydrogenphosphate (CaHPO4), calcium monohydrogenphosphate dihydrate (CaHPO4.2H2O), calcium dihydrogenphosphate (Ca(H2PO4)2); and calcium dihydrogenphosphate monohydrate (Ca(HPO4)2.H2O).
Further, it is preferable that the calcium phosphate to be prepared after the heat treatment is at least one of xcex2-tricalcium phosphate (TCP) and calcium hydroxyphosphate (hydroxyapatite: HAp). Furthermore, it is also preferable that the molar ratio (Ca/P) of calcium to phosphor contained in the mixed material is set to a range of 1.45-1.55, the calcium phosphate precursor to be formed by the soft-mechanochemical compositing reaction is tricalcium phosphate precursor, and the calcium phosphate to be prepared after the heat treatment is xcex2-tricalcium phosphate.
In addition, it is also preferable that the molar ratio (Ca/P) of calcium to phosphor contained in the mixed material is set to a range of 1.62-1.72, the calcium phosphate precursor to be formed by the soft-mechanochemical compositing reaction is hydroxyapatite (HAp), and the calcium phosphate to be prepared after the heat treatment is calcium hydroxyphosphate.
Further, the mixing/milling treatment for the mixed material may be performed by a dry-process. Furthermore, the mixed material may be prepared in a form of slurry and the mixing/milling treatment for the slurry may be performed by a wet-process. In addition, it is preferable that a content (concentration) of solid component contained in the slurry is set to 15-50 wt %. In particular, it is preferable that the mixing/milling treatment for the mixed material is performed by means of a multi-ring type ultrafine mill comprising a number of ring-shaped pulverizing media.
The present invention adopts a countermeasure in which calcium hydroxide (Ca(OH)2) powder is used as a material in place of calcium carbonate that has been conventionally used as the material, and calcium hydroxide and calcium hydrogenphosphate are mixed and milled so that an inter reaction i.e. soft-mechanochemical reaction between acid-base points at surface of material particles is taken place whereby the calcium phosphate powders such as xcex2-tricalcium phosphate or the like is synthesized in a short time.
More concretely to say, the manufacturing method comprises the steps of preparing a mixed material by weighing and mixing calcium hydroxide (Ca(OH)2) powder and calcium dihydrogenphosphate monohydrate powder or the like so that a molar ratio (Ca/P) of calcium to phosphor is set to a range of 1.45-1.72; putting the mixed material into a vessel of a milling device, mixing and milling the mixed material under predetermined milling conditions to form a precursor, and conducting a heat treatment to the obtained precursor at a temperature of 600xc2x0 C. or more thereby to synthesize fine calcium phosphate powders such as xcex2-tricalcium phosphate, calcium hydroxyphosphate or the like.
In the above method, as the material of the calcium hydrogenphosphate, it is preferable to use at least one compound selected from the group consisting of calcium monohydrogenphosphate (CaHPO4), calcium monohydrogenphosphate dihydrate (CaHPO4.2H2O), calcium dihydrogenphosphate (Ca(H2PO4)2) and calcium dihydrogenphosphate monohydrate (Ca(H2PO4)2.H2O).
The above calcium hydroxide (Ca(OH)2) powder and calcium hydrogenphosphate powder are mixed so that a molar ratio (Ca/P) of calcium to phosphor is set to a range of 1.45-1.72 thereby to prepare the mixed material. In particular, when a mixed material controlled to have a molar ratio of 1.45-1.55 is mixed and milled so that the mechanochemical compositing reaction takes place thereby to form a precursor, then the precursor is subjected to a heat treatment at a temperature of 600xc2x0 C. or more, xcex2-tricalcium phosphate (Ca3(PO4)2) (TCP) is efficiently formed in accordance with the following formulae of (1)-(4):
Ca(OH)2+2CaHPO4xe2x86x92Ca3(PO4) 2+2H2Oxe2x80x83xe2x80x83(1)
Ca(OH)2+2CaHPO42.H2Oxe2x86x92Ca3(PO4)2+6H2Oxe2x80x83xe2x80x83(2)
2Ca(OH)2+Ca(H2PO4)2xe2x86x92Ca3(PO4)2+4H2Oxe2x80x83xe2x80x83(3)
2Ca(OH)2+Ca(H2PO4)2.H2Oxe2x86x92Ca3(PO4)2+5H2Oxe2x80x83xe2x80x83(4)
On the other hand, when a mixed material controlled to have a molar ratio of 1.62-1.72 is mixed and milled so that the mechanochemical compositing reaction is take place thereby to form a precursor, then the precursor is subjected to a heat treatment at a temperature of 600xc2x0 C. or more, calcium hydroxyphosphate (Ca10(PO4)6 (OH)2: hydroxyapatite (HAp)) is efficiently formed in accordance with the following formulae (5)-(8):
4Ca(OH)2+6CaHPO4xe2x86x92Ca10(PO4)6(OH)2+4H2O+H2↑xe2x80x83xe2x80x83(5)
4Ca(OH)2+6CaHPO4.2H2Oxe2x86x92Ca10(PO4)6(OH)2+16H2O+H2↑xe2x80x83xe2x80x83(6)
7Ca(OH)2+3Ca(H2PO4)2xe2x86x92Ca10(PO4)6(OH)2+12H2Oxe2x80x83xe2x80x83(7)
7Ca(OH)2+3Ca(H2PO4)2.H2Oxe2x86x92Ca10(PO4)6(OH)2+15H2Oxe2x80x83xe2x80x83(8)
In addition, it is considered that when a predetermined amount of calcium oxide (CaO) is mixed to the above mixed material, it becomes possible to form tetracalcium phosphate (Ca4(PO4)2.O:TTCP) in accordance with the following formulae (9) and (10):
Ca(OH)2+2CaHPO4+CaOxe2x86x92Ca4(PO4)2.O+2H2Oxe2x80x83xe2x80x83(9)
2Ca(OH)2+Ca(H2PO4)2.H2O+CaOxe2x86x92Ca4(PO4)2.O+5H2Oxe2x80x83xe2x80x83(10)
In addition, it is considered that when a predetermined amount of calcium fluoride (CaF2) is mixed to the above mixed material, it becomes possible to form fluorine apatite (Ca10(PO4)6F2) in accordance with the following formulae (11) and (12):
3Ca(OH)2+6CaHPO4+CaF2xe2x86x92Ca10(PO4)6F2+3H2Oxe2x80x83xe2x80x83(11)
xe2x80x836Ca(OH)2+3Ca(H2PO4)2.H2O+CaF2xe2x86x92Ca10(PO4)6F2+12H2Oxe2x80x83xe2x80x83(12)
In the manufacturing method of this invention, when the soft-mechanochemical reaction is advanced in the process of mixing and milling the mixed material, the above various calcium phosphate precursors are formed. The above mechanochemical compositing reaction can be advanced as a solid phase reaction in a dry-process in which a material powder is mixed and milled without adding a dispersing medium to the material powder. On the other hand, the compositing reaction can be also advanced as a liquid phase reaction in a wet-process in which a slurry prepared by dispersing the mixed material powder in a solvent is mixed and milled.
As the milling device for promoting the soft-mechanochemical compositing reaction by mixing and pulverizing the above mixed material, a motor-driven mortar, a vibration mill and a planetary ball mill or the like are considered to be adopted. However, in these milling devices, a centrifugal effect is relatively small, and mechanical stress and impacting forces to be imparted to the material are insufficient. Therefore, even if the milling operation is carried out for about one hour or so, it is very difficult to impart sufficient reaction activity to the mixed material and also difficult to advance the soft-mechanochemical reaction. For this reason, in general, the reaction activity cannot be imparted to the mixed material powder until the material slurry is subjected to the treatment for a long time of about 10-50 hours or more. Accordingly, the above milling devices are not considered to be effective for simplifying the manufacturing processes.
Therefore, in the manufacturing method of the present invention, it is preferable to adopt various impacting-type grinding mills or a powder surface modifying device capable of repeatedly imparting an impacting force to the mixed material in a short time.
In the mixing and milling treatment for advancing the above soft-mechanochemical compositing reaction, the centrifugal effect (Z) to be imparted to the mixed material powder is required to be at least 15. In this connection, the centrifugal effect (Z) is a quantitative index showing a magnitude of pulverizing force, and is a ratio of the centrifugal force (Fc) to a gravitational force (Fg). The centrifugal effect (Z) is expressed by the following formula:
Z=Fc/Fg=rxcfx892/g(xe2x88x92)
wherein r is radius of rotation, xcfx89 is angular speed, and g is gravitational acceleration.
When the centrifugal effect (Z) is less than 15, the impacting force to be imparted to the mixed material is insufficient, and it becomes impossible to increase the reaction activity by forming distortions in crystal structure of the surface portion of the material particles in a short time. Therefore, in order to increase the reaction activity of the mixed material and to prepare the mixed material having a uniformity, it is required to use a milling device capable of imparting impacting force having a centrifugal effect (Z) of 15 or more, preferably 70 or more, and more preferably 150 or more.
In this connection, the method of the present invention therefore uses such an ultrafine mill (multi-ring type pulverizing mill) as shown in FIGS. 1 and 2 as the milling device comprising a number of ring-shaped pulverizing media for rapidly carrying out the soft-mechanochemical compositing treatment. This ultrafine mill is capable of applying impact force and friction to powder particles so as to enhance the reaction activity thereof, and efficiently mixing and milling the powder particles within a short time. The device comprises a cylindrical casing 1, a main shaft 4 which is rotated in the casing 1, and a plurality of sub-shafts 6 which are rotated around the main shaft 4 in linkage with the rotation of the main shaft 4, wherein each of the sub-shafts 6 being provided with many ring members 9 as grinding media. Although the size of each of the ring members 9 as the grinding media depends upon the type and size of the treatment device used, an outer diameter of the member is 25 to 45 mm, and the thickness of the member is several mm. Although the material for constituting the ring members 9 depends upon the physical properties of a material to be processed, the ring members 9 can be composed of stainless steel, ceramic materials such as alumina, zircoma or the like, or a hard carbide material such as WC.
The above casing 1 has an internal peripheral surface 2 having a center axis in a longitudinal direction, and comprises a rotational mechanism 3 provided in the casing 1 serving as a processing chamber. The rotational mechanism 3 comprises the main shaft 4 concentric with the casing 1, a pair of press plates 5 and 5xe2x80x2 which are fixed at a predetermined interval therebetween in the longitudinal direction of the main shaft 4, and the sub-shafts 6 which are fixed by the press plates 5 and 5xe2x80x2 so as to be arranged at the same distance from the main shaft 4 in parallel therewith.
Each of the press plates 5 and 5xe2x80x2 has a form in which the same number of arms as the number of the sub-shafts 6 are radially projected. The form of the press plates 5 and 5xe2x80x2 in which the arms are provided at equal intervals, not a simple disk form, can improve the degree of convection (mixing) of a material to be processed, which is put into the casing 1, and decrease as much as possible the amount of the material to be processed, which is deposited as a dead stock on the upper press plate 5.
Each of the sub-shafts 6 comprises a long bolt-like member having ends that are respectively passed through holes provided at the ends of the arms of both press plates 5 and 5xe2x80x2 and tightened by nuts 7. The upper end of the main shaft 4 is connected directly to a driving Source such as a motor (not shown) or provided with a pulley so that the rotational force of the driving source is transmitted to the main shaft 4 through a V belt.
As shown in FIG. 2, for the purpose of increasing wear resistance, there may be a case where a cylindrical collar 8 is fitted on each of the sub-shafts 6 with a small gap therebetween, and a plurality of ring members 9 are retractably mounted on each of the collar 8. Each of the ring members 9 has an internal diameter sufficiently larger than the outer diameter of the collar 8, and is constructed so as to have a sufficient gap between the internal peripheral surface of the ring member 9 and the external peripheral surface of the collar 8 when the external peripheral surface of the ring member 9 contacts the internal peripheral surface 2 of the casing 1.
The ring members 9 are stacked to form a gap corresponding to the total thickness of 2 to 3 ring members 9 between the upper side of the uppermost ring member 9 and the lower side of the press plate 5, but not closely stacked between both press plates 5 and 5xe2x80x2 without a gap. This stacking structure makes the ring members 9 rotatively around each of the collars 8.
Each of the ring members 9 is formed in a cylindrical form having parallel upper and lower surfaces, which is a so-called washer-like form having smooth upper and lower surfaces, and an outer peripheral surface. If required, the outer peripheral surface may be curved for promoting bite into the powder material.
Agitating blades 10 and 10xe2x80x2 are radially disposed at upper and lower portions of the main shaft 4, which are below the lower press plate 5xe2x80x2 and above the upper press plate 5, respectively, so as to agitate the material to be processed, which is put into the casing 1.
To an upper flange 13 of the casing 1 is fixed an upper cover 11 having a through hole by tightening members such as bolts and nuts, with a packing 12 therebetween. The main shaft 4 is passed through the through hole of the upper cover 11, the through hole being provided with an oil seal 14 for sealing the main shaft 4, and an oil seal holder 15 for holding the oil seal 14. In order to prevent a temperature rise of the material to be processed during grinding, the side of the casing 1 has a jacket structure 16. A refrigerant supply port 17 and discharge port 18 are provided in the jacket 16 so that the material to be processed which is put into the casing 1 can be cooled by continuously supplying any one of various refrigerants into the jacket 16.
In the grinding/milling device (ultrafine mill) constructed as described above, a gap of several millimeters (mm) is formed between the outer periphery of each of the sub-shafts 6 and the inner peripheries of the ring members 9 so that the ring members 9 can be freely independently rotated. The ring members 9 serving as the grinding media are radially moved by an amount corresponding to the gap due to the centrifugal force generated by the rotation of the main shaft 4, and circumferentially rotated in the casing 1 while being pressed on the inner periphery 2 of the casing 1. At the same time, the ring members 9 themselves are rotated around the sub-shafts 6 due to the friction between the inner peripheral surface 2 and the ring members 9. Namely, the ring members 9 are moved in the casing 1 while being repeatedly rotated around the main shaft 4 and each of the sub-shafts 6.
When the raw material mixture powder in an amount corresponding to 10 to 80% of the effective volumes of the grinding portion is put into the casing 1 and then subjected to the soft-mechanochemical treatment by rotating the main shaft 4, the raw material mixture powder is held between the rotating ring members 9 and the internal peripheral surface 2 of the casing 1, and subjected to impact force (compressive force) corresponding to the centrifugal effect caused by the ring members 9 and the grinding/milling function due to the rotation of the ring members 9 themselves. As a result, the raw material mixture powder is ground and dispersed, and, at the same time, strains and distortions are produced in the crystal structure of the particle surfaces of the mixture powder, so that a soft-mechanochemical compositing reaction is rapidly advanced thereby to form a calcium phosphate precursor in which the reactivity of the surfaces of the raw material mixture powder is enhanced. The centrifugal effect Z exerted on the raw material mixture powder is controlled by changing the rotational speed of the main shaft 4.
According to knowledge of the inventors of this invention, it has been confirmed that the soft-mechanochemical compositing reaction to be advanced by mixing and pulverizing the mixed material is greatly influenced by operating conditions such as a kind or magnitude of the mechanical stress, pulverizing mechanism of the milling device, atmosphere for the treatment or the like.
In place of the conventional milling devices such as motor-driven mortar, various ball mills or the like, when there is particularly used a milling device like the above multi-ring media type ultrafine mill having a special pulverizing mechanism provided with a number of ring-shaped pulverizing media, the reactivity of the material mixture can be rapidly increased by the short-time mixing and pulverizing treatment, so that it becomes possible to shorten a required time for the soft-mechanochemical compositing reaction.
In the method of this invention when the mixing/milling operation is performed and acid-base points are formed on surface of the material particles, the soft-mechanochemical reaction is advanced by a reaction mechanism in which new chemical bondings are directly formed by the inter-action between the acid-base points formed on the surfaces of the different material particles, whereby the calcium phosphate precursor is formed. Although this reaction is one kind of a solid-phase reaction, it has a characteristic of exhibiting a high reaction rate, so that a time required for synthesizing calcium phosphate compound can be greatly shortened in comparison with that of the conventional method.
The reaction mechanism of the above soft-mechanochemical reaction mechanism to be used in the method of this invention is quite different from that of the conventional mechanochemical reaction mainly consisting of a liquid-phase reaction disclosed in Japanese Patent Publication No. 3 (1991)-69844 in which a dissolving of solid material is promoted by a wet-type pulverization then a compositing reaction is advanced by a mutual reaction of ions generated in a solution thereby to cause the liquid phase reaction.
That is, the method of this invention is a method wherein acidbase points are generated at the surface of the solid material particles by utilizing the mechanical stress and simultaneously cause the mutual reaction (inter-reaction). In this point, the reaction mechanism used in this invention is also quite different from that of the conventional solid-phase method i.e., a high temperature solid-phase reacting method in which the mutual reaction between the different material particles is advanced by using heat energy thereby to form calcium phosphate compound.
In particular, non-free water such as hydroxyl group and bound water (crystal water) is quite different from free water to be added to the material powder as dispersion medium in the conventional method. The non-free water has a strong function as a catalyser for promoting the mechanochemical compositing reaction to be caused during the mixing and milling the material mixture. Accordingly, when the calcium hydroxide powder having the non-free water i.e., hydroxyl group or calcium hydrogenphosphate having the bound water is used as a starting material like this invention, the mechanochemical reaction can be rapidly advanced in the mixing/milling process thereby to effectively produce calcium phosphate precursor.
The catalytic action by the above non-free waters such as hydroxyl group and the combined water or the like in the soft-mechanochemical reaction is similarly revealed in not only a case where the dry-type mixing/milling operation is performed without adding the non-free water as the dispersing medium but also a case where the wet-type mixing/milling operation is performed to a highly-concentrated material slurry which is prepared by adding the dispersion medium so as to have a solid content of 15-50 wt %, and more preferably to have a solid content of 20-40 wt %.
In particular, when the material mixture to which the dispersion medium such as water is not added is mixed and milled in a dry-process unlike the conventional method, a drying-process is not required to perform to the resulting precursor substance at a stage after the completion of the soft-mechanochemical compositing reaction, so that the precursor substance can be immediately supplied to a heating-treatment process. Therefore, a crystallization of the precursor can be advanced by the heat treatment at a low temperature, so that calcium phosphate compounds such as xcex2-tricalcium phosphate can be manufactured at high efficiency and low cost.
When the precursor substance obtained by the above soft-mechanochemical compositing reaction is subjected to the heat treatment, calcium phosphate compounds such as xcex2-tricalcium phosphate and hydroxy calcium phosphate can be manufactured. The above heat treatment is performed at temperature of 600-800xc2x0 C. for 1-3 hours or at temperature of 900-950xc2x0 C. for 1-10 minutes. Namely, in the heat treatment at 600+ C. or more, when the temperature is set to be low, the time required for the heat treatment is relatively lengthened. On the other hand, when the temperature for the heat treatment is set to be lower than 600xc2x0 C., a part of un-reacted material is left, so that the purity in substantial structure and crystallizing property of the calcium phosphate compound is lowered. When the above temperature and time for the heating treatment are controlled, it becomes possible to adjust and control the purity in substantial structure and crystallinity of xcex2-tricalcium phosphate and hydroxy calcium phosphate.
In the manufacturing method of this invention, for example, calcium hydroxide and calcium dihydrogenphosphate monohydrate powders are used as starting materials so as to prepare a mixed powder of which molar ratio of Ca to P is appropriately controlled and the mixed powder is further mixed and milled in dry-process, so that soft-mechanochemical reaction is rapidly advanced thereby to form xcex2-tricalcium phosphate precursor. Then, when the precursor is subjected to a heat treatment at temperature of 600xc2x0 C. or more, there can be manufactured finely crystallized powder of xcex2-tricalcium phosphate (TCP).
The above soft-mechanochemical reaction is caused even if the dispersing medium such as water or the like is not existing and the reaction is caused by an interaction between acid-base points existing on the surfaces of different material particles. At this time, a mechanochemical dehydrating reaction and an amorphousizing reaction are advanced thereby to produce xcex2-tricalcium phosphate precursor as an intermediate product.
The above mechanochemical dehydrating reaction is quite different from an ordinary heat-dehydrating reaction to be caused by heat energy and the mechanochemical dehydrating reaction is a reaction in which a bonding state of hydroxyl group is changed by the mechanical energy caused in the mixing/milling process. The change of the bonding state of the hydroxyl group takes an important role in forming xcex2-tricalcium phosphate (TCP) precursor by the above soft-mechanochemical compositing reaction. A completion state (degree of advancement) of the above various reactions, composition (purity) and molecular structure of the product or the like are totally evaluated by various analyzing and testing methods such as thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction method (XRD) and Fouier transform infrared microscope (FT-IR) or the like.
In the mixing/milling process in the method of this invention, a chemical interaction is mainly taken place in addition to a mere physical mixing of different material particles. The material particle size is changed by the milling operation thereby to increase surface energy per unit volume of the material particles and to increase lattice inconsistencies such as dislocation of crystals and amorphousizing to be caused in a solid body of the material particles. Such increases of the surface energy and the lattice inconsistency also become one factor for promoting the aforementioned soft-mechanochemical compositing reaction.
In a case where the material mixture is treated under the conditions of mixing/milling by dry-process in the method of this invention without adding a dispersion medium to the material mixture, a milled substance (precursor) to be obtained is dried powder, so that there is no need to adopt a drying process which had been deemed to be an essential process for the synthesizing method based on the conventional wet-type mechanochemical reaction method. Therefore, when the precursor formed by the reaction is directly subjected to the heat treatment, fine particle powder of xcex2-tricalcium phosphate crystal can be obtained while an input amount of the heat energy is reduced. The production of xcex2-tricalcium phosphate is due to the blended molar ratio of Ca to P, and hydroxy calcium phosphate can be also produced by changing the molar ratio through a similar process.
As mentioned above, the mixing/milling process in the method of this invention may be performed in accordance with the dry-type mixing method in which the dispersing medium such as water is not added to the material mixture. However, the same effect can be also obtained in accordance with a wet-type mixing method in which the dispersing medium is added to the material mixture to prepare a material slurry having a high solid content of 15-50 wt %, preferably 20-45 wt %, then the material slurry is mixed/milled. In a case where this wet-type mixing method is adopted, the solid content of the material slurry can be greatly increased in comparison with that of the conventional method, it becomes possible to efficiently manufacture calcium phosphate compounds in a short time. In particular, when the aforementioned multi-ring medium type ultrafine mill is used as the milling device for performing the mixing/milling operation, the effective milling operation can be performed with respect to the slurry having a high solid contents and high viscosity.

Method for producing calcium phosphate powder


A sprocket is formed by fine-blanking a steel plate using a die having a cutting edge shaped to produce rounded edges on the back sides of the sprocket tooth heads, and protrusions on the front sides. Thereafter the edges of the front sides of the sprocket tooth heads are formed in a press so that the protrusions are removed, and the edges of the front sides of the sprocket tooth heads have a rounded cross-sectional shape substantially the same as that of the edges of the front sides.

Most internal combustion engines include a timing transmission in which an endless chain delivers power from a driving sprocket to a driven sprocket. The sprockets have been typically produced by sinter molding of a powder alloy or by skiving bulk steel. However, more recently, because of diverse user requirements, such as improvement of quality and production, cost reduction, short delivery time, and the like, sprockets have been produced by fine blanking of steel plate. Such a process is described in Japanese Laid-Open Patent Publication No. 2002-1449.
Fine blanking is a precision process in which a material to be blanked or punched is constrained so that the material is sheared while compression force is applied to the material from all directions. In fine blanking, a workpiece is held under a high pressure against a die by means of a V-ring, and a portion is punched out of the workpiece by means of a punch, while a counter force is applied by a reverse punch back-up. The fine blanking process is capable of producing parts which are flatter, more uniform, and dimensionally more accurate, and which have a cleaner shear face, than parts produced by conventional stamping.
In the fine blanking process, as illustrated by FIGS. 7(a), 7(b) and 7(c,) a phenomenon known as "penetration," produces a curved portion 260 and a protruding portion 250, as seen in FIG. 7(c), which is a detailed view of a peripheral part of the sprocket shown in FIGS. 7(a) and 7(b). Thus, after fine blanking, another fabrication step, such as turning, milling, or the like, is required to shave or remove the protruding portion. Then, a further finishing step is required, at the location where the protruding portion was removed, in order to provide the front and back sides of the tooth head with the same round cross-section corresponding to the shape of the curved portion 260. Even when the tooth head is finished so that has a symmetric curvature, the process of turning, milling, or the like, can leave a burr at a tooth bottom or on a tooth side, which can cause damage or excessive wear to a chain that engages the sprocket.

Steel plate sprocket and method of producing same


A fiber-reinforced resin wall of a collapsible shipping container large enough and strong enough for shipping about 300 gallons of liquid is made by compression molding a laminate formed of a glass fiber mat sandwiched between resin webs. This material is arranged in a central region of a compression mold cavity for a wall of the container so that the flow of material during compression molding runs laterally from a central region to side edge regions of the molded wall. Horizontal corrugations extend in the same direction as the lateral flow of material and are not intersected by any transverse ribs so that the flow along the horizontal corrugations is not deviated from the lateral direction. This laterally orients the fibers and optimizes the strength of the wall in the horizontal direction, which is important for bulk shipping requirements.

Although there have been many attempts to make collapsible shipping containers of molded resin materials, these containers have not been large enough and strong enough for holding 300 gallons or more of liquid materials. Such a size and capacity is desirable for the loading of trucks and railroad cars; and the ability to hold liquid materials is desirable for shipping food products, chemicals, and many pourable, bulk materials. Collapsibility is desirable so that empty containers are compact on return shipment.
Collapsible metal containers have been made strong enough for these purposes; but they are expensive, heavy, and easily damaged. Non-collapsible and non-reusable containers have also succeeded, but these tend to be more expensive than collapsible and reusable containers.
The invention involves a way of making resin walls of a collapsible shipping container strong enough so that the container can be used repeatedly for shipments of about 300 gallons or more of liquid and comparable density materials. The inventive solution allows a collapsible container to take advantage of the desirable characteristics of molded resin, while being large enough and strong enough to meet the shipping needs of many materials.

Resin wall formation for collapsible shipping container


The disclosure features over 5000 methylation and acetylation sites identified in human cell line, human serum and mouse tissues, peptides (including AQUA peptides) comprising a methylation or acetylation site of the disclosure, antibodies specifically bind to a methylation or acetylation site of the disclosure, and diagnostic and therapeutic uses of the above.

Protein methylation and acetylation are common posttranslational modification that mostly occurs on arginine or lysine residues. Arginine methylation has been reported to regulate RNA processing, gene transcription, DNA damage repair, protein translocation, and signal transduction. Lysine methylation is best known to regulate histone function and is involved in epigenetic regulation of gene transcription.
Protein methyltransferases and demethylases have been implicated in human health and disease (Greer, E. L., and Shi, Y. (2012) Histone methylation: a dynamic mark in health, disease and inheritance. Nature Reviews. Genetics 13, 343-357; Yang, Y, and Bedford, M. T. (2013) Protein arginine methyltransferases and cancer. Nature Reviews. Cancer 13, 37-50). Considering the important biological roles of protein methylation, there is a need for identification of additional methylated proteins and methylation sites.


A mechanical acceleration sensor having a weight movably supported on a casing, a latch lever loaded with a set load and disposed to face the weight, and a firing pin spring-loaded and engaged with the latch lever. The latch lever is disengaged from the firing pin against the set load by inertial movement of the weight relative to the casing, thereby allowing the firing pin to perform a percussive action. A sub-lever is provided in connection with the latch lever. The sub-lever is disposed to face a side of the weight which is opposite to the side thereof that faces the latch lever so as to cooperate with the latch lever to clamp the weight from both sides of the direction of inertial movement of the weight, thereby making it possible to sense acceleration acting on the sensor in both the positive and negative directions of inertial movement of the weight by the inertial movement thereof.

The present invention relates to a mechanical acceleration sensor for activating a gas generator of an inflator in an air bag system or a pretensioner in a seatbelt system. The present invention also relates to a gas-pressure activating apparatus employing the mechanical acceleration sensor.
Vehicles, for example, automobiles, are provided with an air bag system or a seatbelt system. For an inflator in the air bag system or a pretensioner in the seatbelt system, a gas generator is employed as a means of generating a driving medium for the inflator or the pretensioner. The gas generator is activated by an acceleration sensor which operates on sensing a predetermined level of acceleration. Such acceleration sensors include two types, that is, a sensor that outputs an electric signal, and a mechanical sensor that outputs a mechanical displacement of a member. The former is superior in the acceleration pulse discriminating power and hence advantageous in that an erroneous operation is unlikely to occur. On the other hand, it requires a power supply and electrical connection. Therefore, the installation position is limited. In contrast, the latter acceleration sensor is inferior to the former in the acceleration pulse discriminating power, but it is less costly and needs no electric supply nor electrical connection. Therefore, the latter type of acceleration sensor is advantageous in that it can be used without limitation on the installation position. Under these circumstances, various proposals have heretofore been made with regard to the mechanical sensor.
There is one form of such mechanical sensor in which when a predetermined level of acceleration acts on the vehicle, a firing pin of the sensor is percussively actuated to activate the inflator of the air bag system. This type of mechanical sensor has a weight, a latch lever, and a firing pin, which are movably supported on a sensor casing. The firing pin, which is spring-loaded, is released from the hold by the latch lever by the inertial movement of the weight relative to the casing, thereby allowing the firing pin to perform a percussive action (for example, see Japanese Utility Model Application Laid-Open (KOKAI) No. 2-32464, in which, particularly, the position of the weight relative to the latch lever is adjustable.)
However, the above-described conventional mechanical sensor is originally intended to be applied to an air bag. Therefore, in the conventional mechanical sensor, the acceleration sensing direction, that is, the direction of inertial movement of the weight, is set in only one direction. For example, if this mechanical sensor is used as a means for activating a pretensioner attached to a retractor in a seatbelt system, the set-up posture of the mechanical sensor relative to the retractor must be reversed depending upon whether the retractor is installed on the left-hand side of the right-hand side with respect to the vehicle. The limitation on the set-up posture necessitates preparation of different kinds of mechanical sensor in accordance with the position in which the retractor is installed.
Further, in the conventional mechanical sensor, the weight is movably supported on the casing relatively loosely. Therefore, it is difficult to expect an accurate operation, and the operation is readily influenced by the set-up posture of the sensor. In addition, since the space for the operation of the latch lever and the space for the movement of the weight must be provided separately from each other, the outer shape and overall weight of the sensor become large in comparison to the weight of the weight member.

Mechanical acceleration sensor and gas-pressure activating apparatus employing the same


A camera includes a distance detecting device arranged to detect a distance from the camera to an object to be photographed and to output distance information, a flash amount deciding part arranged to decide an amount of flash emission on the basis of the distance information from the distance detecting device, and an aperture value deciding part arranged to decide an aperture value to be used at the time of starting flash emission on the basis of the amount of flash emission.

1. Field of the Invention
This invention relates to a camera arranged to be capable of varying the amount of flash light emission.
2. Description of the Related Art
It has been known to arrange a flash device to accumulate electric energy in a main capacitor to a given capacity level by boosting the voltage of a battery which is provided as a power source for a camera and then to excite and allow a xenon lamp to flash at a given timing. The use of the flash device effectively prevents an object to be photographed from becoming too dark in a dark scene or under a back light condition.
An improvement over the flash device which is also known is arranged to measure the reflected light of the object resulting from flashing and to stop the flash device from flashing when the reflected light reaches a predetermined value of light quantity on an image plane. This arrangement is called a flash light control device. The use of the flash light control device broadens a flash device interlocking range (by preventing an over-exposure for a near distance). It also saves any nearby person from being dazzled too much. This device is widely in use for single-lens reflex cameras on account of these merits.
Meanwhile, cameras of the kind having a distance measuring device for automatically measuring a distance to the object have recently increased in number. The cameras of the kind arranged to be capable of varying their focal lengths and also the cameras of the kind having a flash device of a high guide number also have increased.
However, the use of the above-stated flash light control device for these cameras necessitates an optical system and an electric circuit for measuring reflected light at the time of flashing and also means for actually fitting them, and thus has presented a problem in respect of space and cost. This problem is not only serious for single-lens reflex cameras but especially serious for low-priced, lens-shutter type cameras having various functions, because of lack of space or limited cost.
Another problem lies in that the flash light control on the basis of reflected light of the object resulting from flashing depends on the reflection factor of the object and also those of ambient things. It has been, therefore, sometimes difficult to make an apposite exposure. In accordance with the conventional flash light control method, the photographed face of a person, for example, often becomes darker in a case where he or she is in front of a golden background, and sometimes becomes blankly white when he or she is in front of a background which is blackish as a whole.
Further, in accordance with the arrangement of the conventional flash light control device, the photoelectric current obtainable from the reflected light of the object is very weak. Therefore, the flash light quantity sometimes becomes greatly insufficient through the flash light control due to some flashing noise or the like. To prevent this, the conventional flash light control device necessitates a great amount of efforts and parts for actual applications. Further, the value of light quantity on the image plane becomes unreliable when some dust or a waterdrop sticks to an optical system for flash light control or when shots are taken in the rain.
A further problem with the conventional device lies in that: Although the flash light is not extremely dazzling, it is still dangerous for children's eyes to flash at them from a short distance. In view of this, some people wish to take a picture with the guide number of the flash device lowered. There is another desire to vary the ratio of the flash light to daylight under some distance condition in connection with wide-field distance measurement. There is also a desire for taking a near distance shot while increasing the depth of field.


A method for generating a vibration by a device by using an adjective is provided. The method includes setting at least one fundamental frequency and at least one overlap ratio corresponding to a certain adjective and a degree value of the certain adjective, receiving at least one user input for inputting an adjective and a degree value of the input adjective, and generating at least one vibration corresponding to the input adjective and the degree value of the input adjective based on the setting. The generated at least one vibration has a fundamental frequency and an overlap ratio corresponding to the input adjective and the degree value of the input adjective.

Among various types of haptic feedback, vibration-based haptic feedback (hereinafter referred to as "vibration feedback") are widely used in various mobile devices, such as smart phones and tablet devices, game consoles, and realistic four-dimensional (4D) movie theaters. Also, since vibration feedback is more efficient than other types of feedback, the use of vibration feedback is on the increase currently.
However, in the related art, a method of directly setting a frequency and an amplitude, which are physical properties of a vibration waveform, is mainly used to generate a vibration feedback. Accordingly, it is difficult for an inexpert user to receive a vibration of his desired sense from a device, and it is also difficult to predict and quantify a perceptive sense that a user feels through a vibration.
Therefore, required is vibration generation technology that allows a user to accurately receive a vibration of his desired sense from a device and may easily predict and quantify perceptive properties of a vibration.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.

Method and device for generating vibration based on an adjective


Unidentified player tracking systems and related methods of tracking an unidentified player are disclosed herein. According to one method, an unidentified player initiates a first gaming session on a first networked gaming machine, and the gaming activity data during the first gaming session is accumulated. A printed voucher that includes an identification number is issued in response to input from the unidentified player to terminate the first gaming session. The accumulated gaming activity data is then associated with the identification number of the printed voucher, and the identification number of the printed voucher and the associated gaming activity of the unidentified player is stored for future analysis.

Player tracking systems are used to monitor the gaming activities of players on a casino floor. A common method for monitoring casino players is via a player tracking system. Typically, these systems use cards to identify a player. The player inserts the card before playing a game on the casino gaming machine. The player tracking system uses the information stored on the card to identify the player. Once the player tracking system identifies the player, the system then monitors the player's gaming habits. This includes recording player wagered amounts and the rate at which the player plays the games, and the like. Data relating to the player's gaming habits is then stored in a player tracking system database and/or on the player tracking card.
Despite the advantages of using player tracking cards, there are problems associated with the use of such cards. One problem arises when a first player leaves a gaming machine without first retrieving his player tracking card because the player habits of a second player will be attributed to the first player. Another problem occurs when a first player allows a second person to use the first player's tracking card. In this scenario, the first player accrues tracking points that are not actually earned by him as the player tracking system inaccurately records and associates the data as first player information. Yet another problem with player tracking cards is a casino or gaming establishment is only able to monitor the gaming habits of those players who are enrolled in the casino's loyalty (i.e., player's club) program. What is needed is a system and method to non-intrusively track unidentified players during one or more gaming sessions.

Unidentified player tracking system and related methods


A yeast .alpha.-factor expression system is provided comprised of a truncated leader sequence, containing the .alpha.-factor signal peptide and one glycosylation site, linked by a processing site to a non-yeast protein-encoding sequence.

Kurjan et al. (1982) Cell 30:933-943 discloses the first cloning and sequencing of a gene encoding a yeast .alpha.-factor precursor gene. Kurjan et al., U.S. Pat. No. 4,546,082, also reports the cloning of this gene, and suggests that the .alpha.-factor leader sequence can be employed to direct the secretion of heterologous proteins in yeast. The patent, however, does not contain data which would indicate that the patentees ever successfully employed the .alpha.-factor leader to express and secrete a heterologous protein in yeast.
EPO Publication No. 116,201 discloses the first successful application of the .alpha.-factor leader to direct the expression and secretion of an heterologous protein, epidermal growth factor, from a transformed yeast. Subsequent to this work, there have been additional reports of the expression of heterologous proteins in yeast employing the .alpha.-factor leader. See, e.g., Elliott et al. (1983) Proc. Nat'l Acad. Sci. USA 80:7080-7084; Bitter et al. (1984) Proc. Nat'l Acad. Sci. USA 81:5330-5334; Smith et al. (1985) Science 229:1219-1229; EPO Publication Nos. 114,695; 123,228; 123,294; 123,544; 128,773; and 206,783. See also Brake et al. in Protein Transport and Secretion, p.103 (J. M. Gething ed. 1984).
The expression systems in the above reports produce a full-length .alpha.-factor leader fused to a heterologous protein. While the above work demonstrates that the .alpha.-factor expression system is widely useful, it is not generally predictable prior to performing the experiment whether a particular heterologous protein will be successfully secreted, processed and biologically active. See, e.g., EPO 206,783, supra, pp. 2-5; Rothblatt et al. (1987) EMBO J. 6:3455-3463; V. L. MacKay, "Secretion of Heterologous Proteins in Yeast" (in press).
There have been several reports, based on unpublished data, that deletions from the "pro" region of the .alpha.-factor leader (between the signal peptide and the first spacer) causes substantial declines in the amount of non-yeast protein secreted by yeast transformed the heterologous constructs. Sidhu et al. (1987) Gene 54:175-184, reports that yeast acid phosphatase (PHO5) is secreted into the medium from a heterologous construct employing both a full-length .alpha.-factor leader, and a truncated .alpha.-factor leader, but that expression levels are 3-4.times. less than for the PHO5 gene under the control of its homologous leader. It has also been reported that deletions in the prepro-.alpha.-factor precursor gene results in substantial declines in secretion of the native .alpha.-factor peptide. See, e.g., V. L. MacKay, supra; Rothblatt et al., supra.
A need exists, therefore, to improve the .alpha.-factor expression system, particularly for applications to non-yeast proteins that are not efficiently produced by current .alpha.-factor expression constructs.

Expression and secretion of heterologous proteins in yeast employing truncated alpha-factor leader sequences


An object of the present invention is to provide a multiband antenna, an antenna array, and a wireless communications device that can achieve miniaturization while preventing deterioration in radiation efficiency. To this end, an antenna according to the present invention includes: a conductor reflection plate; a first antenna that includes a first antenna element and is provided on the conductor reflection plate; and a second antenna that includes a second antenna element having an electromagnetic resonance frequency that is a frequency different from an electromagnetic resonance frequency of the first antenna element included in the first antenna, and that is provided on the conductor reflection plate, wherein each of the first antenna element and the second antenna element includes: a C-shaped conductor that is a substantially C-shaped conductor having a split section formed in such a way that an annular conductor becomes partially discontinuous; and a conductor feed line that is electrically connected with one part out of both parts of the C-shaped conductor facing each other across the split section, and that constitutes an electric circuit for feeding power to the C-shaped conductor.

In recent years, a multiband antenna that enables communication over a plurality of frequency bands for ensuring communication capacity has been put to practical use, for example, as a base station for mobile communication and an antenna device for Wi-Fi (registered trademark) communication equipment.
A multiband antenna is disclosed as a multiband antenna array in, for example, FIGS. 11, 12, and 13 of PTL 1. This antenna array includes an antenna reflector, and an array of high-band and low-band crossed-dipole antenna elements alternately aligned on the antenna reflector. Further, central conductive fences 1340 are provided between the alignments to reduce mutual coupling. In addition, in PTL 2, in FIGS. 2a, 2b, and 2c, a decoupling element (decoupling structural element 17) is arranged between individual antenna elements (radiation element module 1) of a single-frequency antenna array.

Multiband antenna, multiband antenna array, and wireless communications device


The present invention relates to mounting decorative devices, emblems and flags to automobiles and more particularly to the mounting of such items to the hood ornament of an automobile. The present invention is attached to the hood ornament by a first body means which fits over the hood ornament and which contains on its inside rubberized strips or gaskets or the like which cause it to fit snuggly onto the hood ornament. A second body means is of similar shape and a slightly larger size than the first body means and fits over the first body means and snaps onto the first body means. The second body means is transparent so that any designs, emblems, logos or the like placed between the two body means will be visable from outside the device. The two body means have rounded edges so that the risk of injury from impalement thereon is greatly reduced. The first and second body means may have holes therein with said holes being aligned between the first and second body means so that pins which are approximately U-shaped may have one leg of the pin inserted into the holes with the second leg thereof flush against the exterior of the second body means and so that flags attached to the exterior of the pin may hang freely therefrom without the necessity of having a flag staff which protrudes from the device and causes a greater risk of injury should anyone or anything come into contact with the device.

Devices for attaching decorative elements to the exterior of an automobile have been known for some time. U.S. Pat. No. 1,310,234, issued on Jul. 15, 1919 to T.F. Denning relates to the attachment of a windwheel and flag to the radiator cap of an automobile. The Denning patent utilizes a clamp to the radiator filling tube to which are attached windwheel and flags. Such a device is dangerous as it is rigidly fixed and objects may therefore be readily impaled upon it and such a device is also not readily adaptable for use in conjunction with a hood ornament instead of a radiator cap.
Another example of a previous automobile decorative device is U.S. Pat. No. 1,573,757, issued Feb. 16, 1926 to S.T. Elmo W Acosta, which is screwed onto the radiator in place of the radiator cap and rigidly afixes a flag thereto. This device also has the same problem as the Denning patent.
Also known are devices for holding flags which attach directly to the drip gutter or rain gutter of an automobile. Such devices also have the problems of being dangerous, as an object may be readily impaled upon such a device, and of not being able to be used in conjunction with the hood ornament of an automobile. The following patents are all examples of such a device: U.S. Pat. No. 1,928,563, issued Sep. 26, 1933 to R.G. Hetzel; U.S. Pat. No. 2,294,986, issued Sep. 8, 1942 to T.E. Hynek; U.S. Pat. No. 2,643,841, issued Jun. 30, 1953 to L. Wallace; U.S. Pat. No. 3,136,289, issued Jun. 9, 1964 to E.E. Johnson; U.S. Pat. No. 3,178,139, issued Apr. 13, 1965 to B. McFarlin; U.S. Pat. No. 3,260,486, issued Jul. 12, 1966 to E.L. Groff; U.S. Pat. No. 3,493,203, issued Feb. 3, 1970 to E.V. Gualano; and U.S. Pat. No. 3,540,685, issued Nov. 17, 1970 to E.V. Gualano.
The present device differs from those previously known in that the present device is attachable to the hood ornament of a car with said hood ornament being bendably mounted so that impalement is not likely to occur. The present device is also formed so as to avoid having any protruding flag stance or other edges which could readily cause injury. Further, the present device is also mounted in such a way that if the pressure is great enough the device will detach so that no injury is caused thereby.

Automobile hood ornament decorative device


A light emitting diode is disclosed that includes a silicon carbide substrate and a light emitting structure formed from the Group III nitride material system on the substrate. The diode has an area greater than 100,000 square microns and has a radiant flux at 20 milliamps current of at least 29 milliwatts at its dominant wavelength between 390 and 540 nanometers.

The present invention relates to light emitting diodes (LEDs) and in particular relates to LEDs formed with active portions of Group III nitrides on silicon carbide substrates.
As set forth in Ser. No. 11/037,965 cited above ("the '965 application"), significant improvements have recently been demonstrated in the output of light emitting diodes based on the Group III nitride material system using conductive silicon carbide substrates. In particular, the '965 application discloses light emitting diodes that have high brightness on a unit area basis.
A light emitting diode (LED) is a p-n junction semiconductor diode that emits photons when forward biased. Thus, light emitting diodes produce light based upon the movement of electrons in a semiconductor material. Therefore, LEDs do not require (although they can be used in conjunction with) vapors or phosphors. They share the desirable characteristics of most semiconductor-based devices, including high efficiency (their emissions include little or no heat), high reliability and long life. For example, typical LEDs have a mean time between failures of between about 100,000 and 1,000,000 hours meaning that a conservative half lifetime for an LED is on the order of 50,000 hours.
In particular, an LED's emitted light has a frequency (which in turn relates directly to wavelength and color in accordance with well-understood principles of physics) based upon the energy difference between permitted energy levels in the material, a characteristic referred to as the bandgap. The bandgap is a fundamentally property of the semiconductor material and its doping. Thus, LEDs formed in silicon (Si, bandgap of 1.12 electron volts (eV)) will have energy transitions in the infrared (but not the visible) portions of the spectrum. Silicon-based diodes are thus used for items such as low-cost sensors in which visibility to the human eye is either unimportant or specifically undesired. LEDs formed in gallium arsenide (bandgap 1.42 eV), or most commonly in silicon-doped aluminum gallium arsenide (AlGaAs) will emit in the visible portion of the spectrum, but at lower frequencies that produce infrared radiation and red and yellow light.
In turn, because green, blue, and ultraviolet (UV) photons represent higher frequency colors (E=hυ) within (and beyond) the visible spectrum, they can only be produced by LEDs with bandgaps of at least about 2.2 eV. Such materials include diamond (5.47 eV), silicon carbide (2.99 eV) and Group III nitrides such as GaN (3.4 eV). In addition to producing green, blue or ultraviolet light per se, wide bandgap LEDs can be combined with red and green LEDs to produce white light, or with phosphors that produce white light when excited by blue or UV light, or both.
For several reasons, the Group III nitride compositions (i.e., Group III of the periodic table), particularly GaN, AlGaN, InGaN and AlInGaN are particularly useful for blue-emitting LEDs. As one advantage, they are "direct" emitters, meaning that when an electron transition occurs across the bandgap, much of the energy is emitted as light. By comparison, "indirect" emitters (such as silicon carbide) emit their energy partially as light (a photon) and predominantly as vibrational energy (a phonon). Thus Group III nitrides offer efficiency advantages over indirect transition materials. The Group III nitrides will also be referred to herein as the Group III nitride material system.
As another advantage, the bandgap of ternary and quaternary Group III materials (e.g., AlGaN, InGaN, AlInGaN) depends upon the atomic fraction of the included Group III elements. Thus the wavelength (color) of the emission can be tailored (within limits) by controlling the atomic fraction of each Group III element in a ternary or quaternary nitride.
Wide bandgap semiconductors have been, however, historically more difficult to produce and work with than gallium-arsenide or gallium phosphide (GaP). As a result, blue and UV-emitting LEDs have lagged behind GaP-based LED's in their commercial appearance. For example, silicon carbide is physically very hard, has no melt phase, and requires high temperatures (on the order of about 1500-2000° C.) for epitaxial or sublimation growth. The Group III nitrides have relatively large nitrogen vapor pressures at their melting temperatures and thus are likewise difficult or impossible to grow from a melt. Additionally, difficulties in obtaining p-type gallium nitride (and other Group III nitrides) remained a barrier to diode production for a number of years. Accordingly, the commercial availability of blue and white-emitting LEDs is more recent than the corresponding availability of GaP-based and GaAs-based LEDs.
For comparison and other relevant purposes, lighting is typically quantified as to its output. One typical unit of measure is the lumen, defined as a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candela (cd) intensity. In turn, the candela is the base unit of luminous intensity in the International System of Units that is equal to the luminous intensity in a given direction of a source which emits monochromatic radiation of frequency 540×1012 hertz and has a radiant intensity in that direction of 1/683 watt per unit solid angle.
Using lumens as the unit of measurement, an intensity of 1200-1800 lumens is typical of incandescent bulbs and 1000-6000 lumens (depending upon circumstances) is typical in natural daylight. Light emitting diodes, however, are much less intense, for example on the order of about 10-100 lumens. One reason is their small size. Thus, applications for single (or small groups of) LEDs have historically gravitated towards indication (e.g. the register of a hand-held calculator) rather than illumination (a reading lamp). Although the availability of blue LEDs and corresponding white-emitting devices have moved such LEDs into wider commercial availability, for illumination purposes, several (or more) LEDs are typically grouped together to provide the desired output.
Because of their typical size and structure, the output of LEDs is often measured in units other than lumens. Additionally, an LED's output also depends upon the applied current, which in turn depends upon the potential difference applied across the diode. Thus, the output of an LED is often referred to as its radiant flux (Rf) and is expressed in milliwatts (mW) at a standard 20 milliamp (mA) drive current.
Blue LEDs are becoming more frequently included in consumer electronic devices, particularly small displays. Common examples include items such as computer screens, personal digital assistants ("PDAs") and cellular phones. In turn, these small devices drive demand for LEDs with reduced size ("footprint"). Such LEDs, however, must still operate at low forward voltages (Vf) and high light output. To date, however, reducing the size of the blue-emitting Group III nitride devices has tended to increase their forward voltage and reduce their radiant flux.
As noted above, the LEDs disclosed in the '965 application offers significant advantages in increased brightness (using the standard parameters noted above) and reduced forward voltage even at small size.
Although small, relatively thin LEDs are advantageous for smaller devices (such as cellular phone displays); the incorporation of LEDs into larger devices presents different challenges. For example, using greater numbers of small diodes in larger displays can reduce energy conversion, increase power consumption and require the manufacturer to purchase, assemble and maintain a greater number of components. Larger numbers of smaller components can also increase weight, size, volume and the number of required electrical connections. Statistically, larger numbers of smaller devices will include a larger absolute number of defects and may require the manufacturer to maintain larger inventories in order to maintain or increase a given reliability.
As one example, electronic visible displays such as oscilloscopes, televisions, and computer monitors, have historically been based upon cathode ray tubes ("CRTs"). In recent years, however, the advances in various technologies commonly grouped as "flat panel" displays have rapidly displaced cathode ray tubes for many purposes and in particular for consumer uses such as televisions and monitors for personal computers.
Additionally, these and other technologies have in turn driven the growth of much larger displays for consumer and other personal use. Examples include plasma-based and liquid crystal ("LCD") television screens that are quite large compared to their technological ancestors; i.e., 46 inch flat-panel televisions in place of 21 inch CRT-based televisions.
In particular, liquid crystal displays operate by changing the orientation of liquid crystals, and thus their appearance, using appropriate electrical controls. Liquid crystals do not emit light, however, and thus LCD displays such as televisions must be back lit by some additional source. The availability of "RGB" (red, green, and blue) or white light emitting diodes in large quantity at competitive cost offers such an appropriate back lighting source.
A large display, however, requires a large number of light emitting diodes. In turn, the individual diodes must be physically supported and functionally incorporated into electronic circuits. Furthermore, although light emitting diodes are highly efficient in comparison to incandescent lighting, they still generate a finite amount of energy as heat. Thus, incorporating hundreds or thousands of light emitting diodes into larger applications, particularly those used indoors, correspondingly generates noticeable, or even troublesome amounts of heat and other technological challenges.
Because both complexity and heat are typical problems that must be addressed in designing and using electronic equipment (including large flat-panel displays) that incorporates LEDs, a need exists, and corresponding benefits are desired, for further increasing the efficiency and output of light emitting diodes. This need includes the call for light emitting diodes that produce white light from blue emitting diodes either by incorporating phosphors or through their combination with red and green LEDs.
Accordingly, a need exists for continual improvement in the output of small-size LEDs formed in the Group III nitride silicon carbide material system.

High output group III nitride light emitting diodes


It is an object of the present invention to provide a highly efficient semiconductor laser unit having excellent temperature characteristics, in which electrons or holes are suppressed from overflowing from the active layer to the cladding layers while the threshold of current density is maintained low. The present invention is to provide a semiconductor laser unit fundamentally composed of an active layer and cladding layers in which the active layer is interposed between the cladding layers the semiconductor laser unit comprising: a multiquantum barrier layer including well layers and barrier layers disposed between the active layer and the cladding layers or disposed in the cladding layers close to the active layer, wherein the well and barrier layers have a high reflectivity with respect to the electrons and holes at a position close to .GAMMA.-point in the reciprocal lattice space, and also the well and barrier layers have a high reflectivity with respect to the electrons and holes at a position close to at least one of the primary symmetrical points.

The present invention relates to a highly efficient semiconductor laser unit having appropriate temperature characteristics used for the light source of a laser printer or bar code reader.
The semiconductor laser unit is fundamentally composed of an active layer and cladding layers, in which the active layer is interposed between the cladding layers. Various semiconductor materials are used for the semiconductor laser unit. For example, a red semiconductor laser for oscillating a beam of light of short wavelength is usually composed of AlGaInP material. In this case, a beam of light of short wavelength is defined as a beam of light of which the wavelength is shorter than the wavelength of an infrared ray which is in the oscillating band of a common semiconductor laser.
However, in the case of this AlGaInP material, it is not possible to provide a large band gap between the cladding and active layers. Therefore, a problems is caused in which carriers, especially electrons, overflow from the active layer to the cladding layers so that the laser characteristics are deteriorated. That is, the luminous efficiency of the laser is low due to the overflow of carriers, and further the temperature characteristics are deteriorated.
As a means for solving the above problems, a multiquantum barrier structure has been proposed. The multiquantum barrier structure is a superlattice in which well layers and barrier layers are alternately laminated. Due to the changes in potential and effective mass, the multiquantum barrier structure is capable of reflecting electrons of high energy compared with the barrier layer composing the multiquantum barrier structure. When the multiquantum barrier layer is provided between the active and cladding layers or in the cladding layers close to the active layer, the electrons in the active layer can be prevented from overflowing, so that the laser characteristics such as temperature characteristics and luminous efficiency can be improved, which is disclosed and published in the following documents:
Official gazette of Japanese Unexamined Patent Publication No. 4-114486; "Design of multiquantum barrier (MQB) and experimental verification of reflecting effect of electronic waves" by Takagi and et al. on page 527 to 535 of Vol. J74-C-I of theses of C-I of Electronic Information Communication Society published in December of 1991; "Experimental verification concerning MQB effect of AlGaInP visible radiation laser" by Arimoto et al. disclosed in 19a-V-5 in the fifty third lecture meeting of the Applied Physics Society held in autumn of 1992; and "Superposed Multiquantum Barriers for InGaAlP Hetero-junctions" by Furuya et disclosed in IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 28, NO 10, OCT. 1992, pp 1977-1982.
However, in the case of the multiquantum barrier structure of the prior art, consideration is given only to the reflection of electrons which occurs at a position close to point .GAMMA. which is one of the symmetrical points in the reciprocal lattice space, and consideration is not given to the reflection of electrons which occurs at a position close to point X or L which is another primary symmetrical point. In this connection, the reciprocal lattice space is a space for expressing a crystal structure, and the substantial lattice of the crystal structure and the reciprocal lattice in the reciprocal lattice space can be converted to each other in accordance with a predetermined converting expression. When the actions of electrons in the crystal and those of holes are described using this reciprocal lattice space, it becomes easy to treat them physically. In the case where various lattices are three-dimensionally expressed using this reciprocal lattice space, symmetrical points are referred to as .GAMMA., L and X points.
In the conventional multiquantum barrier structure described above, electrons at a position close to .GAMMA. point are effectively reflected, so that they are prevented from overflowing to the cladding layers, however, electrons at a position close to X or L point are not reflected, so that they overflow. Consequently, electrons having high energy move to X or L point, the energy level of which is low, and they overflow to the cladding layers.
In FIG. 10, is shown a band structure of points .GAMMA. and X of the multiquantum barrier proposed in the above mentioned "Design of multiquantum barrier (MQB) and experimental verification of reflecting effect of electronic waves" by Takagi and et al. on page 527 to 535 of Vol. J74-C-I of theses of C-I of Electronic Information Communication Society published in December of 1991. In this structure, the cladding layers 51 and the barrier layer 53 of the multiquantum barrier 52 are composed of the composition of (Al.sub.0.7 Ga.sub.0.3)InP, so that the energy level of point .GAMMA. and that of point X are permitted to be approximately the same. In this case, the well layer 54 is composed of GaInP. In this connection, numeral 55 is an active layer of GaInP.
In FIG. 1, an example of the reflectivity of electrons is shown when the electrons are reflected on the multiquantum barrier having the band structure of .GAMMA. point described above. In this case, U.sub.0 is 115 meV, the well layer thickness is 6 atomic layers, and the barrier layer thickness is 5 atomic layers. As can be seen in the graph of FIG. 11, when the multiquantum barrier is used, the reflectivity is high even in the case of electrons of relatively high energy, so that the electrons are prevented from overflowing. However, electrons move from a position close to point .GAMMA. on the active layer 55 to a position close to point X on the first barrier layer 53a (shown in FIG. 10) of the multiquantum barrier, and the electrons are reflected by the reflectivity shown in FIG. 12. As can be seen from the graph shown in FIG. 12, the reflectivity of electrons at the position close to point X is low in an energy region (in a region close to 120 meV in the example shown in FIG. 12), and electrons in this region pass through the multiquantum barrier 52 and overflow onto the cladding layers 51. As a result, the electrons overflow outside from the active layer 55.
As described above, in the multiquantum barrier structure of the prior art, carriers are not sufficiently suppressed from overflowing, and the most appropriate multiquantum barrier structure can not be provided.
It is an object of the present invention to provide a highly efficient semiconductor laser unit having excellent temperature characteristics, in which electrons or holes are suppressed from overflowing from the active layer to the cladding layers while the threshold of current density is maintained low.

Multiquantum barrier laser having high electron and hole reflectivity of layers


An elastomeric carboxylated nitirle rubber glove has a stress retention, after six minutes at 100% extension, of rom 50% to 70%. It is made using prevulcanized carboxylated nitrile rubber latex with 2 to 6% by weight methacrylic acid equivalent.

This invention relates to elastomeric gloves, particularly but not exclusively medical and surgical gloves, and to a method of making them.
Close fitting rubber gloves are well known and are used for a number of purposes, principally medical and surgical. It is especially important in some uses for the gloves to fit closely on the hand, at least in the finger and palm regions. To ensure this close fitting, it is customary for users to wear gloves of slightly smaller dimensions than their hands in order to ensure a close snug fit. However, some discomfort can arise during use of the gloves, from the continued application of pressure by the glove on the hand.
It has been proposed in EP-B-0456333 to overcome this problem by making such gloves of nitrile butadiene rubber since this material has long been known to show stress relaxation properties. In particular, the patent describes gloves made of a carboxylated elastomeric material comprising 0.1 to 0.5 parts zinc oxide per 100 parts carboxylated nitrile butadiene rubber, the material being such that when stretched 100% of its length with an initial stress and the 100% stretch maintained, the material relaxes within 6 minutes of the initial stress so that the 100% stretch is maintained by a reduced stress which is less than 80%, more preferably less than 50%, of the initial stress. The effect of this is that whilst the gloves are fight fitting when initially donned, the stress subsequently relaxes within six minutes so as to relieve the pressure applied to the user""s hands and so provide greater comfort and sensitivity. In the only Example in the patent, the stress retention of a carboxylated nitrile butadiene rubber glove was 0% after six minutes.
Whilst this basic approach of using the known stress relaxation properties of carboxylated nitrile rubbers does provide some alleviation of the problem of user discomfort due to stress retention in rubber gloves, it does not provide a wholly satisfactory answer. In particular, we have found that the stress retention which occurs in known carboxylated nitrile rubbers such as taught by EP-B-0456333 is actually too low such that its use can result in poor fitting of gloves to the hands and fingers as the gloves gradually become loose with time because of creep due to stress relaxation. In particular, we have found that stress retention of less than 50% as is found in known such rubbers, can give rise to problems and that, surprisingly, far improved user comfort and satisfaction is achieved with a stress retention of from about 50 to about 70%.
Copolymer latices containing carboxyl-modified nitrile rubber and a diene are disclosed in EP 0559150A. Such latices can be used to provide rubber articles having high oil resistance and high mechanical strength.
Accordingly, in one aspect, the present invention provides an elastomeric glove made of a carboxylated nitrile rubber having from 2 to 6% by weight methacrylic acid equivalent and which exhibits a stress retention of from 50 to 70%, said stress retention being the percentage retention of the initial stress after six minutes at 100% extension. Gloves of the invention give better fitting to the hands and fingers and hence improved sensitivity of touch on extended wearing compared with those that have low stress retention of less than 50%.
The stress retention of the gloves produced according to the present invention is higher than that illustrated and obtained by EP-B-0456333, but lower than that of gloves made from natural rubber latex or polychloroprene latex. The gloves of the invention can be made to be good fitting and yet not to cause fatigue to the hands on extended wearing.
Gloves made of conventional carboxylated nitrile rubbers have a low stress retention, i.e. well below 50%. Accordingly, gloves of the present invention cannot be made by simply using known nitrile rubber glove technology since the stress retention would then be too low. We have found, however, that stress retention can be controllably increased to the levels required in the present invention by using prevulcanised nitrile butadiene rubber latex, i.e. latex in which some vulcanisation of the rubber by sulphur has been effected before the gloves are made. Prevulcanisation (or maturation) of the rubber in this way then enables the desired stress retention of 50 to 70% to be obtained following a conventional dipping production process.
The gloves of the invention can be non-chlorinated or chlorinated or polymer-coated, as desired. The carboxylated nitrile rubber latex used to make the gloves is preferably a copolymer of acrylonitrile, butadiene, and an unsaturated carboxylic acid. The unsaturated carboxylic acid is of acrylic acid type and may be, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, or sorbic acid. Methacrylic acid is preferred. The ratio of acrylonitrile to butadiene in the copolymer will depend upon the use to which the glove is to be put. For an industrial glove requiring good resistance to organic solvents, the acrylonitrile content may be as high as 37 to 40% of the polymer. For surgical and other medical gloves, solvent resistance is much less important than softness and flexibility. In this case, a copolymer of much lower acrylonitrile content is used, usually about 26 to 30% of the polymer. The preferred amount of unsaturated carboxylic acid is 2-6% methacrylic acid equivalent, most preferably 3-5.5% methacrylic acid equivalent.
In the gloves of the invention, the nitrile rubber is cross-linked both by conventional vulcanisation (i.e. by sulphur, vulcanisation accelerators and zinc oxide), and by ionic crosslinking using polyvalent metal oxides, preferably zinc oxide. The amount of polyvalent metal oxide (eg. zinc oxide) used for the ionic cross-linking is preferably from about 0.1 to 0.5 phr (per hundred parts of nitrile rubber, dry basis), more preferably from 0.2 to 0.4 phr. The polyvalent metal oxides effect crosslinking ionically between carboxylate groups in the polymer chain. The amount of sulphur used for crosslinking is from 1 to 3 phr, preferably from 2 to 3 phr. The crosslinking of the nitrile polymers achieved by sulphur crosslinks (both during the process and during prevulcanisation) is the major effect and the ionic crosslinking via the polyvalent metal oxide and the carboxyl groups is the minor effect. The selection of a low level of carboxylation and of a low polyvalent metal oxide level keep the level of ionic crosslinks in the nitrile rubber relatively low. Ionic crosslinks exhibit higher stress relaxation characteristics than do sulphur crosslinks. The stress retention achieved can be controlled by varying the amounts of, and balance between, the two types of crosslink.
According to the invention, the carboxylated nitrile rubber latex is subjected to a prevulcanisation (or maturation) step. Preferably, this is at least at 30xc2x0 C. for a minimum of 16 hours for fully compounded latex. As will be clear to those skilled in the art, however, different temperatures and times can be used to provide essentially the same effect and the invention encompasses these equivalents. In general, lower temperatures will require longer times, and higher temperatures shorter times. The practical minima and maxima will be readily determinable by those skilled in the art with any particular latex formulation, bearing in mind the ultimate purpose of providing gloves with a stress retention of from 50 to 70%.
In order that the invention may be more fully understood, the following Examples are given by way of illustration only.
Carboxylated acrylonitrile butadiene latices with a carboxylation level of 4%-6% methacrylic acid equivalent content were compounded according to Formulation A given in Table 1. Formulation B given in Table 2 has also been used. The latex was prevulcanized for 40xc2x0 C. for various periods of time. Prevulcanization at 50xc2x0 C. of has also been used. After the required heating time, the latex was cooled. Gloves were prepared from the prevulcanized latex by well-know procedures, involving the steps of coagulant dipping, leaching, drying and vulanizing. The gloves were then finished, either by washing and powdering, or by washing and chlorination, as indicated in the Examples that follow.
The gloves were tested according to ASTM methods.
In the following Examples, carboxylated acrylonitrile butadiene rubber is referred to as XNBR, zinc dibutyl dithiocarbamate as ZBuD, zinc mercaptobenzthiazole as ZMBT and zinc diethyl dithiocarbamate as ZDEC.


A device for the golf practice of short strokes and putting for a practicing person having a chest and upper arms. The device has an elongate object adapted to be fitted between the chest and the upper arms of the practicing person. The object has a central portion curved in a backward direction comprising opposite curved side portions that are curved in the same backward direction and extending to outer portions. The outer portions are curved in a forward direction opposite the backward direction. The device is held across the chest and outer portions are disposed behind the upper arms during the golf club stroke.

A method and golf aid device for aiding golf player to correctly swing a golf club.
Many golf players are novice or have only intermediate skills. When playing golf, it is important to correctly swing the golf club to improve the chances of hitting the golf ball accurately. More particularly, many golf players experience problems when executing short strokes and putting due to lack of proper technique. The arms and wrists of the golf player have a tendency to control the movement of the golf club even though the golf player desires to perform the movement as a coordinated rotation of the chest and the arms. The erroneous manner of performing the swinging movement is most likely attributed to the fact that, in most cases, the movements of arms and hands are simple and easy to carry out compared to a coordinated rotation of the entire upper body of the golf player including the chest and arms. However, most modern scientific studies of the game of golf indicate that a considerably higher precision in the golf club swinging movement can be acquired by executing the movement as a rotation of the chest while the arms and hands are passive. The first time this correct movement is taught to a beginner of the game of golf, it is often experienced by the novice golf player as an unnatural movement. The novice golf player often thinks that more power are involved than are really needed for an effective golf club stroke. In earlier days, golf players were probably unknowingly assisted by the rigid clothes worn in the past. The clothes that were worn the golf was a new game restricted the movement of the arms more than today""s casual clothes do to the detriment of the novice golf players.
As a result, many novice and intermediate golf players are struggling with the golf club swing and find it difficult to maintain the arms in the correct position relative to the chest during the swing. Many attempts have been made to properly instruct novice and intermediate level golf players to achieve a smooth and effective golf club swing. However, many golf players are still swinging the golf club incorrectly. There is a need for an inexpensive easy and convenient golf playing aid that forces the golf player to move the upper arms correctly relative to the chest of the golf player. There is also a need for an aid that may be quickly fitted on the player that does not interfere directly with the gripping and movement of the golf club and that is inexpensive to manufacture and takes the individual characteristics of the body structure and swing movement of each player into consideration.
The present invention is a device for the golf practice of short strokes and putting for a practicing person having a chest and upper arms. The device has an elongate object adapted to be fitted between the chest and the upper arms of the practicing person. The object has a central portion curved in a backward direction comprising opposite curved side portions that are curved in the same backward direction and extending to outer portions. The outer portions are curved in a forward direction opposite the backward direction. The device is held across the chest and outer portions are disposed behind the upper arms during the golf club stroke.