Safety device for seat belt

A safety device for a set belt includes a retractor having a rack gear on a circumferential outer surface of which the seat belt is wound; a pretensioner operated upon a collision of a car and rotating the rack gear in a direction for winding the seat belt; a release unit installed adjacent to the pretensioner, operated after the pretensioner operates the rack gear, and rotating the rack gear in a direction for unwinding the seat belt; and a switch unit receiving a manipulation force for operating the release unit, generating electricity, transferring the electricity to the release unit, and operating the release unit.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C 119(a) to Korean Patent Application No. 10-2013-0145502 filed on Nov. 27, 2013 in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety set forth in full.

BACKGROUND

Exemplary embodiments of the present invention relate to a safety device for a seat belt, and more particularly, to a safety device for a seat belt, which winds a seat belt upon a collision of a car and provides an operation of unwinding the seat belt when escaping the car, thereby improving the safety of an occupant.

In general, in a car, a safety belt is regarded as a device which most largely contributes for an occupant to survive upon an accident. When a collision of the car occurs, since a pretensioner operates first and tightens a loosely worn seat belt, the occupant may be kept positioned correctly. Since an air bag is deployed after the pretensioner operates, it is possible to minimize a shock applied to the occupant by the air bag.

In the conventional art, because a substantially large tension is applied to the seat belt due to the operation of the pretensioner, difficulties exist in unfastening the seat belt from a buckle after the deployment of the air bag. Therefore, it is demanded to cope with this problem.

The background art of the present disclosure is disclosed in Korean Unexamined Patent Publication No. 2010-0032679 (dated Mar. 26, 2010 and entitled “Lever Crank Type Pretensioner for Seat Belt”)

SUMMARY

An embodiment of the present invention relates to a safety device for a seat belt, which winds a seat belt upon a collision of a car and provides an operation of unwinding the seat belt when escaping the car, thereby improving the safety of an occupant.

In an embodiment, a safety device for a set belt includes: a retractor having a rack gear on a circumferential outer surface of which the seat belt is wound; a pretensioner operated upon a collision of a car and rotating the rack gear in a direction for winding the seat belt; a release unit installed adjacent to the pretensioner, operated after the pretensioner operates the rack gear, and rotating the rack gear in a direction for unwinding the seat belt; and a switch unit receiving a manipulation force for operating the release unit, generating electricity, transferring the electricity to the release unit, and operating the release unit.

The pretensioner includes a movable gear having a side surface on which teeth to be meshed with the rack gear are formed; a first support member supporting the movable gear; and a first explosion part exploded by an operation of an impact sensor, and moving the first support member in a direction facing the rack gear.

The pretensioner and the release unit are disposed in a housing, and the first support member is pushed by a pressure of a gas produced due to an operation of the first explosion part and is moved in the housing.

The first explosion part is disposed in a first projection, and the gas produced as the first explosion part is operated moves the first support member and the movable gear in a direction facing away from the first explosion part.

The release unit includes a release gear disposed at a position opposite to the movable gear; a second support member supporting the release gear; and a second explosion part exploded by the electricity transferred from the switch unit, and moving the second support member in a direction facing the first support member.

A pair of movable gears are installed on the first support member to be parallel to each other, and a pair of release gears for pushing the movable gears are installed on the second support member to be parallel to each other.

The pretensioner and the release unit are disposed in a housing, and the second support member is pushed by a pressure of a gas produced due to an operation of the second explosion part and is moved in the housing.

The second explosion part is disposed in a second projection, and the gas produced as the second explosion part is operated moves the second support member and the release gear in a direction facing away from the second explosion part.

The switch unit includes a case defining an outer shape of the switch unit; a button member installed in the case and operated in a push type; a first connection part connecting the button member and the pretensioner, separated from the button member by an operation of the pretensioner, and releasing restriction of the button member; and a second connection part converting a pressing operation of the button member into electricity, and transferring the electricity to the release unit.

The second connection part includes a piezoelectric ceramic receiving a pressure through the button member, and generating electricity; and a connection core wire transferring the electricity generated by the piezoelectric ceramic, to the release unit.

The safety device further includes a safety latch connected to one end of the seat belt which is installed in a shape passing over the abdomen of an occupant; a fastening buckle having a mounting space into which the safety latch is inserted, and secured to the car; a latch restriction part installed to be movable into and out of the fastening buckle, and fastened to the fastening buckle through the safety latch; and a release wire inserted into the fastening buckle, passing through the latch restriction part, moved by an operation of the release unit, and releasing restriction of the latch restriction part.

The fastening buckle includes a buckle housing secured to the car, and having a buckle hole which allows the latch restriction part to pass therethrough; and a guide member secured in the buckle housing, formed into a shape for receiving the latch restriction part, and guiding movement of the latch restriction part.

The latch restriction part includes a restriction body extending in a vertical direction; engagement protrusions projecting from side surfaces of the restriction body to be engaged with the safety latch; and a transverse hole defined through the restriction body, and allowing the release wire to be inserted therethrough.

One end of the release wire is connected to the second support member of the release unit, and the other end of the release wire is movable through the transverse hole of the restriction body.

The safety device further includes an elastic member having a lower end which is connected to the guide member and an upper end which is connected to the latch restriction part, and pulling the latch restriction part in a direction facing the guide member by elastic force.

According to the embodiment of the present disclosure, in a safety device for a seat belt, since a pretensioner operates and winds the seat belt by a predetermined length upon a collision of a car and then an air bag may be deployed, a shock applied to an occupant by the air bag may be reduced, whereby the safety of the occupant may be improved.

Also, according to the embodiment of the present disclosure, since manipulation of a switch unit for operating a release unit may be possible after the pretensioner operates, the misoperation of the release unit may be prevented, whereby the occurrence of a safety-related accident may be prevented.

Further, according to the embodiment of the present disclosure, since the release unit is operated and decreases the tension of the safety belt after the pretensioner operates, the seat belt may be easily unfastened from a buckle, whereby the occupant may safely escape the car.

Moreover, according to the embodiment of the present disclosure, since a safety latch may be unfastened from a fastening buckle for fastening the seat belt as a release wire is disengaged from a latch restriction part in conformity with the operation of the release unit, the safety of the occupant may be further improved.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to accompanying drawings. However, the embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

FIG. 1is a side view schematically illustrating a state in which a safety device for a seat belt in accordance with an embodiment of the present disclosure is installed,FIG. 2is a cross-sectional view schematically illustrating a switch unit in accordance with the embodiment of the present disclosure,FIGS. 3 and 4are broken-away perspective views schematically illustrating the main construction of a safety driving section in accordance with the embodiment of the present disclosure, andFIG. 8is a block diagram of the safety device for a seat belt in accordance with the embodiment of the present disclosure.

As shown inFIGS. 1,4,8and9, a safety device1for a seat belt in accordance with an embodiment of the present disclosure includes a retractor20which has a rack gear26on the circumferential outer surface of which a seat belt12is wound, a pretensioner40which is operated upon a collision of a car and rotates the rack gear26in a direction for winding the seat belt12, a release unit50which is disposed adjacent to the pretensioner40, is operated after the pretensioner40rotates the rack gear26and rotates the rack gear26in a direction for unwinding the seat belt12, and a switch unit60which is applied with a manipulation force for operating the release unit50, generates electricity, transfers the electricity to the release unit50and operates the release unit50.

The seat belt12is worn on the body of an occupant10who is seating on a seat11, and is connected to a buckle14. In detail, one end of the seat belt12is connected to the retractor20through an anchorage16, and the other end of the seat belt12passes sequentially over the chest of the occupant10and a tongue13and then over the abdomen of the occupant10and is connected to a safety latch120.

The retractor20retracts the seat belt12with a predetermined tension and prevents the seat belt12from being wound, when the body of the occupant10moves forward during a collision or a sudden stop, to reduce injuries to the occupant10.

The rack gear26is rotatably disposed in the retractor20, and the seat belt12is wound on the circumferential outer surface of the rack gear26.

The rack gear26is constituted by a circular column-shaped rotation member22on the circumferential outer surface of which the seat belt12is wound, and disc-shaped circular gears24which are respectively installed on both ends of the rotation member22.

Teeth are formed on the circumferences of the circular gears24, and portions of the circular gears24project into a housing32of a safety driving section30.

Various kinds of driving devices may be used as the safety driving section30so long as they fall within a technical spirit that the safety driving section30rotates the rack gear26and winds the seat belt12before an air bag is deployed and is then operated by the manipulation force from the occupant10and rotates the rack gear26in the direction for unwinding the seat belt12after the air bag is deployed.

The safety driving section30according to the embodiment includes the housing32, the pretensioner40, and the release unit50.

The pretensioner40and the release unit50are disposed in the housing32, and openings34are defined through a side wall of the housing32which faces the retractor20.

The rack gear26is installed such that portions of the rack gear26project into the housing32through the openings34.

A first projection36projects from one end (the lower end inFIG. 4) of the housing32, and a second projection38projects from the other end (the upper end inFIG. 4) of the housing32.

The pretensioner40is installed in the housing32adjacent to the one end of the housing32. Various kinds of driving devices may be used as the pretensioner40so long as they fall within a technical spirit that the pretensioner40is operated upon a collision of a car and rotates the rack gear26in the direction for winding the seat belt12.

The pretensioner40in accordance with the embodiment of the present disclosure includes movable gears42on the side surfaces of which teeth to be meshed with the rack gear26are formed, a first support member44which supports the movable gears42, and a first explosion part46which is exploded by an operation of an impact sensor90and moves the first support member44in a direction where the movable gears42are meshed with the rack gear26.

In the case where the space defined in the housing32extends in a vertical direction, the movable gears42are disposed to be moved in the vertical direction.

The teeth to be meshed with the portions of the circular gears24which project into the housing32are formed on the side surfaces of the movable gears42. The movable gears42are disposed in a pair on the first support member44in such a way as to be parallel to each other.

The first support member44is installed on the lower ends of the movable gears42in a horizontal direction (when viewed inFIG. 4), and the first explosion part46is disposed below the first support member44.

The first explosion part46is disposed on the bottom of the first projection36. The gas produced as the first explosion part46is operated pushes the first support member44and the movable gears42upwards.

The first explosion part46is operated by a control signal from a control unit100which is transferred with a sensing value of the impact sensor90.

The first support member44is restricted in its movement by protrusions which protrude into the housing32, and is moved in the housing32by being pushed by the pressure of the gas produced by the operation of the first explosion part46.

As shown inFIGS. 1 to 4, the release unit50is disposed adjacent to the pretensioner40. Various kinds of driving devices may be used as the release unit50so long as they fall within a technical spirit that the release unit50is operated after the pretensioner40rotates the rack gear26and then rotates the rack gear26in the direction for unwinding the seat belt12.

The release unit50according to the embodiment of the present disclosure includes release gears52which are disposed at positions opposite to the movable gears42, a second support member54which supports the release gears52, and a second explosion part56which is exploded by the electricity transferred from the switch unit60and moves the second support member54. toward the first support member44.

The release unit50positioned at the upper end of the housing32is disposed opposite the pretensioner40.

The release gears52are upwardly disposed to be opposite to the movable gears42. The release gears52for pushing the movable gears42are disposed in a pair on the second support member54in such a way as to be parallel to each other, by which pushing of the movable gears42may be stably carried out.

The release gears52may be formed into various shapes without departing from a technical spirit that they push the movable gears42downward.

The release gears52according to the embodiment are formed into rod shapes, and the second support member54is disposed on the upper ends of the release gears52to be placed in the horizontal direction.

The first support member44is restricted in its movement by the protrusions which protrude into the housing32, and is moved in the housing32by being pushed by the pressure of the gas produced by the operation of the first explosion part46.

The second support member54is restricted in its movement by protrusions which protrude into the housing32, and is moved in the housing32by being pushed by the pressure of the gas produced by the operation of the second explosion part56.

The second explosion part56is disposed on the top of the second projection38. The gas produced as the second explosion part56is operated pushes the second support member54and the release gears52downwards.

Various kinds of switches may be used as the switch unit60so long as they fall within a technical spirit that the switch unit60is applied with a manipulation force for operating the release unit50, generates electricity, transfers the electricity to the release unit50and operates the release unit50.

The switch unit60according to the embodiment of the present disclosure includes a case62which defines the outer shape of the switch unit60, a button member64which is installed in the case62and is operated in a push type, a first connection part70which connects the button member64and the pretensioner40and is separated from the button member64by the operation of the pretensioner40to release the button member64from restriction, and a second connection part80which converts a pushing operation for the button member64into electricity and transfers the electricity to the release unit50.

The switch unit60is disposed at a position where it is convenient to manipulate the switch unit60. The button member64is installed on the case62which defines the outer shape of the switch unit60.

The button member64is operated by a pushing operation, and the first connection part70is inserted through a side of the button member64.

The first connection part70includes a first covering member72and a core wire74. One end of the core wire74is connected to the first support member44or the movable gears42of the pretensioner40, and the other end of the core wire74is inserted through the side of the button member64.

Since the first covering member72surrounds the outer surface of the core wire74, interference between the core wire74and a surrounding object is prevented when the core wire74is moved in conformity with the operation of the pretensioner40.

Various types of electricity generation devices may be used as the second connection part80so long as they fall within a technical spirit that the second connection part80converts a pushing operation for the switch unit60into electricity and transfers the electricity to the release unit50.

The second connection part80according to the embodiment of the present disclosure includes a piezoelectric ceramic86which is applied with a pressure through the button member64and generates electricity, a connection core wire82which transfers the electricity generated by the piezoelectric ceramic86, to the release unit50, and a second covering member84which surrounds the outer surface of the connection core wire82.

The piezoelectric ceramic86as an element which generates a voltage when a pressure is applied thereto may covert mechanical vibration energy into electrical energy or vice versa, and has high conversion efficiency.

The piezoelectric ceramic86is disposed below the button member64. The connection core wire82, which transfers the electricity generated by the piezoelectric ceramic86, to the second explosion part56of the release unit50, is formed of a conductor as a main material.

The second covering member84is placed around the outer surface of the connection core wire82and prevents electricity flowing through the connection core wire82, from being directed to another member.

The impact sensor90installed in the car senses an impact of the car and transfers a sensing value to the control unit100, and the control unit100operates the air bag and the pretensioner40based on the sensing value of a speed sensor and the sensing value of the impact sensor90.

FIG. 9is a front view schematically illustrating a state in which the safety latch in accordance with the embodiment of the present disclosure is fastened to a fastening buckle,FIG. 10is a perspective view schematically illustrating the state in which the safety latch in accordance with the embodiment of the present disclosure is fastened to the fastening buckle,FIG. 11is an exploded perspective view schematically illustrating the state in which the safety latch in accordance with the embodiment of the present disclosure is unfastened from the fastening buckle,FIG. 12is a cross-sectional view schematically illustrating the state in which the safety latch in accordance with the embodiment of the present disclosure is fastened to the fastening buckle, andFIG. 13is a cross-sectional view schematically illustrating the state in which the safety latch in accordance with the embodiment of the present disclosure is unfastened from the fastening buckle.

As shown inFIGS. 9 to 13, the safety device1for a seat belt in accordance with the embodiment of the present disclosure further includes the safety latch120, a fastening buckle130, a latch restriction part140, a release wire150, and an elastic member160.

The safety latch120is connected to the other end of the seat belt12(on the left side of the seat11when viewed inFIG. 9) which is installed to pass over the abdomen of the occupant10.

The safety latch120according to the embodiment of the present disclosure includes a latch body122which has the shape of a metal piece, and an engagement hole124which is defined to pass through the latch body122.

The engagement hole124is defined in a shape corresponding to the cross-section of the latch restriction part140. Since the engagement hole124and the latch restriction part140according to the embodiment of the present disclosure are defined and formed to have a quadrangular sectional shape, rotation of the safety latch120is restricted when the latch restriction part140is inserted through the engagement hole124.

The fastening buckle130may be formed into various shapes so long as it falls within a technical spirit that it defines a mounting space134into which the safety latch120is inserted to be secured with respect to the car.

The fastening buckle130according to the embodiment of the present disclosure includes a buckle housing132which is secured to the car and has a buckle hole133for allowing the latch restriction part140to pass therethrough, and a guide member136which is secured in the buckle housing132and is formed into a shape capable of receiving the latch restriction part140to guide the movement of the latch restriction part140.

The buckle housing132is open in a direction in which the safety latch120is inserted into the buckle housing132, and the buckle hole133is defined through the upper wall of the buckle housing132(when viewed inFIG. 11) such that the latch restriction part140may be moved through the buckle hole133.

The guide member136is secured in the buckle housing132and guides the expansion and contraction of the elastic member160.

Since the guide member136is formed into a quadrangular box shape which is open at the upper end thereof, the upward and downward movement of the latch restriction part140having the quadrangular cross-sectional shape and the movement of the elastic member160connected to the latch restriction part140and the bottom of the guide member136is guided.

The latch restriction part140is movably disposed in the fastening buckle130. The latch restriction part140may be formed into various shapes so long as it falls within a technical spirit that it is engaged with the fastening buckle130by passing through the engagement hole124of the safety latch120.

The latch restriction part140according to the embodiment of the present disclosure includes a restriction body142, engagement protrusions144, a transverse hole146, and a hook element148.

The restriction body142is formed to have a quadrangular sectional shape and extends in the vertical direction. The engagement protrusions144protrude from side surfaces of the restriction body142to be engaged with the lower surface of the latch body122.

Since the engagement protrusions144are engaged with the latch body122, it is possible to prevent the latch restriction part140from being discharged out of the fastening buckle130through the buckle hole133.

The transverse hole146is defined to transversely pass through the restriction body142. The release wire150is inserted through the transverse hole146to restrict the upward and downward movement of the latch restriction part140.

The release wire150is inserted into the fastening buckle130, passes through the latch restriction part140, and is moved by the operation of the release unit50to release the restriction of the latch restriction part140.

One end of the release wire150is connected to the second support member54of the release unit50, and the other end of the release wire150is movable through the transverse hole146of the restriction body142.

The lower end of the elastic member160is connected to the guide member136, and the upper end of the elastic member160is connected to the latch restriction part140. Various kinds of biasing devices may be used as the elastic member160according to the embodiment of the present disclosure so long as they fall within a technical spirit that the elastic member160biases the latch restriction part140toward the guide member136by elastic force.

The upper end of the elastic member160is hooked to the hook element148which is provided to the lower end of the latch restriction part140, and the lower end of the elastic member160is hooked to a hook element137which is provided to the bottom of the guide member136.

Since the elastic member160according to the embodiment of the present disclosure uses a tensile coil spring, it is possible to provide excellent elastic force in view of a cost.

Hereafter, operations of the safety device1for a seat belt in accordance with the embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

FIG. 5is a cross-sectional view schematically illustrating a state before the pretensioner in accordance with the embodiment of the present disclosure operates,FIG. 6is a cross-sectional view schematically illustrating a state in which the pretensioner in accordance with the embodiment of the present disclosure operates and the rack gear is rotated in the direction for winding the seat belt, andFIG. 7is a cross-sectional view schematically illustrating a state in which the release unit in accordance with the embodiment of the present disclosure operates and pushes the movable gears and the rack gear is rotated in the direction for unwinding the seat belt.

As shown inFIG. 5, the movable gears42and the release gears52are disposed opposite each other with the rack gear26of the retractor20interposed therebetween.

As shown inFIGS. 2,6and8, the control unit100which is transferred with the sensing value of the impact sensor90upon a collision of the car operates the first explosion part46of the pretensioner40.

Alternatively, an electrical signal generated by the impact sensor90may be directly transferred to the first explosion part46without passing through the control unit100and may operate the first explosion part46.

The gas produced by the explosion of the first explosion part46pushes the first support member44upwards, and the movable gears42are moved upward along with the first support member44.

As the teeth formed on the side surfaces of the movable gears42are meshed with the rack gear26, the rack gear26is rotated in the direction for winding the seat belt12(the counterclockwise direction inFIG. 6).

As the seat belt12is wound by a predetermined length by the rotation of the rack gear26, an air bag may be deployed in a state in which the space between the occupant10and the seat11is narrowed, whereby it is possible to reduce injuries to the occupant10.

Because the core wire74connected to the first support member44is also moved upward as the first support member44is moved upward, the other end of the core wire74which is inserted through the side of the button member64is separated from the button member64.

Since the downward movement of the button member64becomes possible after the core wire74is separated from the button member64, the occupant10presses the piezoelectric ceramic86by pushing the button member64.

The electricity generated by pressing the piezoelectric ceramic86is transferred to the second explosion part56through the connection core wire82.

As shown inFIGS. 1 and 7, by the gas produced as the second explosion part56is exploded, the second support member54is moved downward along the inside space of the housing32.

Since the release gears52which are connected to the second support member54push the movable gears42downwards, the rack gear26which is meshed with the movable gears42is rotated in the direction for unwinding the seat belt12(the clockwise direction inFIG. 7).

By this fact, since the tension of the seat belt12is decreased, the occupant10may escape the car after unfastening the seat belt12from the buckle14, whereby the safety of the occupant10may be improved.

Operations in the state in which the safety latch120, the fastening buckle130, the latch restriction part140and the release wire150are additionally disposed to improve the safety of the safety device1for a seat belt will be described below.

As shown inFIGS. 5 and 12, since the movement of the release wire150connected to the second support member54is restricted before the explosion of the second explosion part56is implemented, the movement of the restriction body142of the latch restriction part140is also restricted and the safety latch120is kept fastened to the fastening buckle130.

That is to say, since the latch restriction part140projects out of the fastening buckle130through the engagement hole124of the latch body122and the buckle hole133of the buckle housing132, the leftward and rightward movement of the latch body122is restricted.

Because the occupant10may check the fact that the latch restriction part140projects out of the buckle housing132, it may be confirmed that the safety latch120is kept stably fastened to the fastening buckle130.

As shown inFIGS. 7 and 13, as the second support member54is moved downward by the explosion of the second explosion part56, the release wire150which is connected to the second support member54is moved and is separated from the transverse hole146of the latch restriction part140.

Then, the latch restriction part140is moved downward by the weight of the latch restriction part140and the elastic force of the elastic member160which pulls the latch restriction part140downward.

Since the latch restriction part140is moved downward by being moved out of the engagement hole124of the latch body122and the buckle hole133of the buckle housing132, the safety latch120may be unfastened from the fastening buckle130.

As the seat belt12which passes over the abdomen of the occupant10becomes loose due to unfastening of the safety latch120, the occupant10may unfasten the seat belt12from the buckle14and escape the car, whereby the safety of the occupant10may be improved.

As is apparent from the above descriptions, according to the embodiment of the present disclosure, since the pretensioner40operates and winds the seat belt12by the predetermined length upon a collision of a car and then an air bag may be deployed, a shock applied to the occupant10by the air bag may be reduced, whereby the safety of the occupant10may be improved.

Also, since manipulation of the switch unit60for operating the release unit50may be possible after the pretensioner40operates, the misoperation of the release unit50may be prevented, whereby the occurrence of a safety-related accident may be prevented.

Further, since the release unit50is operated and decreases the tension of the safety belt12after the pretensioner40operates, the seat belt12may be easily unfastened from the buckle14, whereby the occupant10may safely escape the car.

Moreover, since the safety latch120may be unfastened from the fastening buckle130for fastening the seat belt12as the release wire150is disengaged from the latch restriction part140in conformity with the operation of the release unit50, the safety of the occupant10may be further improved.