The present invention relates to a bicycle crank structure which has a firm support structure comprising a crankshaft coupled in a frame hub of a bicycle, and crank arms coupled to both ends of the crankshaft, and which has an assembly structure that is easily reparable and replaceable. A bicycle crank structure is provided wherein, the crankshaft has provided thereto: a main shaft provided in the frame hub; coupling shafts each integrally formed on both ends of the main shaft and protruding towards the outer side of the hub; and binding holes each penetrating in a predetermined length direction inside the respective coupling shafts. The binding holes are formed so that the inner diameters thereof gradually decrease towards the inside, and first fastening holes, communicating with the binding holes and having inner diameters that are smaller than the minimum values of the inner diameters of the binding holds, extend in a predetermined length direction towards the inside of the main shaft via the insides of the coupling shafts so as to be formed as plugged holes. Recess parts and protrusion parts are repeatedly arranged on the outer circumferential surfaces of the coupling shafts in the length directions of the coupling shafts, and cut holes, communicating with the binding holes and the first fastening holes, are each formed on a recess part on one side, and a recess part on the other side facing the recess part on the one side.
The present invention relates to a bicycle crank structure which has a firm support structure comprising a crankshaft coupled in a frame hub of a bicycle, and crank arms coupled to both ends of the crankshaft, and which has an assembly structure that is easily reparable and replaceable. After an adhering part (300), a moving part (400) and an expansion inducing part (500) are assembled, a fastening bolt (700) passes through a first insertion hole (402) of the moving part (400) via a second insertion hole (601) of a cap part (600), and moves by being screw-coupled to a second fastening hole (301) of the adhering part (300), and thus is screw-coupled to a first fastening hole (111) of a coupling shaft (120) of the crankshaft (100). Here, as a result of the fastening to the first fastening hole (111) of the coupling shaft (120), the adhering part (300) moves towards the inner side of a binding hole (121) as a result of the screw-coupling to the second fastening hole (301) of the adhering part (300), and at the same time, the expansion inducing part (500) coupled to the moving part (400) moves. Here, first control tabs (502) of the expansion inducing part (500) guide by being bound to cut holes (124) of the coupling shaft (120), and the outer circumferential surface of the expansion inducing part (500) strongly presses the inner circumferential surface of the binding hole (121), and thus the coupling shaft (120) expands towards the outside so that the inner circumferential surface of a shaft hole (210) of the crank arm (200), the inner circumferential surface adhering to the outer circumferential surface of the coupling shaft (120), is tightly pressed, and thus the bicycle crank structure is capable of having a firm assembly structure.
The present invention relates to a carbon composite and a method for preparing the carbon composite. The carbon composite, which is prepared with a predetermined thickness by layering carbon fibers impregnated in an epoxy resin, has a first carbon layer, a core layer, and a second carbon layer, which are sequentially formed, wherein the core layer is formed from a synthetic foam to be molded in a thickness corresponding to 0.2-0.6 of the total thickness.
B32B 27/12 - Produits stratifiés composés essentiellement de résine synthétique adjacente à une couche fibreuse ou filamenteuse
B32B 27/20 - Produits stratifiés composés essentiellement de résine synthétique caractérisée par l'emploi d'additifs particuliers utilisant des charges, des pigments, des agents thixotropiques
B32B 27/26 - Produits stratifiés composés essentiellement de résine synthétique caractérisée par l'emploi d'additifs particuliers utilisant des durcisseurs
A method for manufacturing a carbon fiber-reinforced composite material spring, according to the present invention, may comprise the steps of: forming a first carbon fiber layer by winding, around a mandrel, a carbon fiber prepreg that is gelled by impregnating a carbon fiber with a resin; forming a second carbon fiber layer by winding, on the first carbon fiber layer, a second carbon fiber prepreg of a knitted fabric shape that is gelled by impregnating a carbon fiber with a resin; forming a third carbon fiber layer by winding, on the second carbon fiber layer, a third carbon fiber prepreg of a knitted fabric shape that is gelled by impregnating a carbon fiber with a resin; obtaining a first spring material of a tubular shape by removing the mandrel when the first to third carbon fiber layers are partially cured; injecting the first spring material into a mold having a forming space of a helical shape; curing the first spring material into a third spring material of a helical shape by injecting high pressure air into a hollow of the first spring material inserted into the mold so that the first to third carbon fiber layers are expanded and integrated with each other; separating the cured third spring material of a helical shape from the mold; and producing a finished product of a carbon fiber-reinforced composite material spring by cutting the third spring material of a helical shape by a predetermined length.
B29K 105/12 - Présentation, forme ou état de la matière moulée contenant des agents de renforcement, charges ou inserts de longueur réduite, p. ex. filaments coupés, fibres coupées ou crins
Provided is a compound bow comprising: a bow main body; upper and lower pulley assemblies; a bowstring; and first and second cam cables, wherein at least one of the first and second cam cables is coupled to the fixing projection that moves along as a cam module moves, is wound on a cam cable winding portion via a compensation projection, and then extends toward the other side pulley assembly, and a front portion of the cam module is in contact with the one cam cable and thus the one cam cable is bent when the cam module is moved, to thus release the one cam cable from the cam cable winding portion via the compensating projection from the fixing projection that the one cam cable is coupled, to thereby maintain constant tension of the cam cable and keep the power of the bow.
Disclosed herein is a body frame for a bicycle which is able to provide higher strength in such a way to use a carbon material even when the outer diameters of a top tube, a bottom tube, a seat tube, a chain tube, etc. have the thickness of a body frame of a classical bicycle, while relatively reducing the weight of the body frame. For this, the body frame for a bicycle according to the present invention is configured in such a way that each of the top tube, the bottom tube and the seat tube is made in a circular shape wherein the outer diameters are same from one end to the other end of each tube, and the flesh thickness of each tube is relatively thicker at the other end portion than one end portion, and each tube is made of a carbon material.
B62K 3/04 - Cadres ayant une barre supérieure sensiblement horizontale
B62K 19/16 - Cadres de cycle caractérisés par le matériau ou la section transversale des éléments du cadre le matériau étant entièrement ou principalement en plastique
A compound bow has an improved vibration damping function. The compound bow includes a bow main body including a handle and a pair of limbs; upper and lower pulley assemblies each including a pulley and a cam; a bowstring; first and second cam cables that are wound around the cam of each of the upper and lower pulley assemblies as the bowstring is pulled; a bowstring support bar whose one end is coupled to the handle and whose other end is coupled to a cushioning member that contacts the bowstring; and a first cam cable anti-vibration bar including a coupling bar coupled to the handle, and an anti-vibration member that is coupled to the rear end of the coupling bar and whose rear surface contacts one of the first and second cam cables when the bowstring is released to thus return to an original position.
Provided is a self-tunable compound bow including: a bow main body including a pair of limbs that are respectively coupled to both ends of a handle; upper and lower pulley assemblies that are respectively coupled to the rear end of each limb; a bowstring; and first and second cam cables that are wound around a cam of each of the upper and lower pulley assemblies as the bowstring is pulled. A contact pin is formed in one of the pulley assemblies, in which the contact pin is in contact with the first cam cable when the bowstring is pulled, and an indicator is formed in the other of the pulley assemblies, in which the indicator is in contact with the second cam cable and moves when the bowstring is pulled in a guide hole formed in the pulley of the other of the pulley assemblies.
According to one embodiment of the present invention, a compound bow using a stopper device, comprises: a through-hole (252) formed so as to enable a bow string (150) to be placed therein prior to being drawn; and a vertical cut-out unit (256) formed so as to enable the bow string (150) to pass therethrough when the bow string (150) is drawn in the through-hole (252).
