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US 5,628,470 AGranted
Seat belt webbing retractor
AssigneeTRW Vehicle Safety Systems Inc.
InventorsGary M. Ray, Robert F. Rogers
Life of this patent
Estimating the term…
Abstract
A seat belt webbing retractor (10) includes a belt webbing spool (50) and a length of belt webbing (16) wound on the belt webbing spool. A spring (82) biases the belt webbing spool (50) for rotation in a belt retraction direction. A pair of rotatable cable spools (90, 100) and a cable (110) transmit the biasing force of the spring (82) to the belt webbing spool (50) to apply a retraction force to the belt webbing (116). Each of the cable spools (90, 100) has a predetermined configuration to provide a desired retraction force curve (230).
Claims11
A vehicle occupant safety apparatus comprising:
- a belt webbing spool supported for rotation about a belt webbing spool axis in a belt retraction direction and an opposite belt withdrawal direction;
- a length of belt webbing wound on said belt webbing spool, said belt webbing being extensible about a vehicle occupant to restrain the occupant;
- a shaft spool fixed for rotation with said belt webbing spool in the belt retraction direction and in the belt withdrawal direction, said shaft spool having an outer peripheral surface, said outer peripheral surface of said shaft spool having a non-conical configuration;
- a spring spool supported for rotation about a spring spool axis in first and second opposite directions, said spring spool axis being spaced apart from said belt webbing spool axis, said spring spool having an outer peripheral surface, said outer peripheral surface of said spring spool having a non-conical configuration;
- a rewind spring connected with said spring spool for biasing said spring spool for rotation in the first direction to apply retraction force to said spring spool;
- and
- an elongate flexible member extending between said outer peripheral surface of said spring spool and said outer peripheral surface of said shaft spool for transmitting retraction force from said spring spool to said shaft spool to bias said belt webbing spool for rotation in the belt retraction direction;
- said rewind spring being enclosed within a first portion of said spring spool;
- said first portion of said spring spool having a minimum radius as determined by the diameter of said rewind spring and having a minimum axial length as determined by the axial height of said rewind spring, the radius of said spring spool being substantially constant over the axial extent of said first portion of said spring spool.
6 more elements
A vehicle occupant safety apparatus comprising:
- a belt webbing spool supported for rotation about a belt webbing spool axis in a belt retraction direction and an opposite belt withdrawal direction;
- a length of belt webbing wound on said belt webbing spool, said belt webbing being extensible about a vehicle occupant to restrain the occupant;
- a shaft spool fixed for rotation with said belt webbing spool in the belt retraction direction and in the belt withdrawal direction, said shaft spool having an outer peripheral surface, said outer peripheral surface of said shaft spool having a non-conical configuration;
- a spring spool supported for rotation about a spring spool axis in first and second opposite directions, said spring spool axis being spaced apart from said belt webbing spool axis, said spring spool having an outer peripheral surface, said outer peripheral surface of said spring spool having a non-conical configuration;
- a rewind spring connected with said spring spool for biasing said spring spool for rotation in the first direction to apply retraction force to said spring spool;
- and
- an elongate flexible member extending between said outer peripheral surface of said spring spool and said outer peripheral surface of said shaft spool for transmitting retraction force from said spring spool to said shaft spool to bias said belt webbing spool for rotation in the belt retraction direction;
- said non-conical configuration of said outer peripheral surface of said spring spool including:
- a first portion of said spring spool from which said flexible member extends when a relatively small amount of said belt webbing is withdrawn from said belt webbing spool, the radius of said first portion of said spring spool gradually increasing over the axial extent of said first portion of said spring spool;
- a second portion of said spring spool from which said flexible member extends when substantially more than a small amount of said belt webbing is withdrawn from said belt webbing spool, the radius of said second portion of said spring spool rapidly increasing over the axial extent of said second portion of said spring spool;
- and
- a third portion of said spring spool from which said flexible member extends when from about half to all of said belt webbing is withdrawn from said belt webbing spool, the radius of said spring spool being substantially constant over the axial extent of said third portion of said spring spool.
9 more elements
A vehicle occupant safety apparatus comprising:
- a belt webbing spool supported for rotation about a belt webbing spool axis in a belt retraction direction and an opposite belt withdrawal direction;
- a length of belt webbing wound on said belt webbing spool, said belt webbing being extensible about a vehicle occupant to restrain the occupant;
- a shaft spool fixed for rotation with said belt webbing spool in the belt retraction direction and in the belt withdrawal direction, said shaft spool having an outer peripheral surface, said outer peripheral surface of said shaft spool having a non-conical configuration;
- a spring spool supported for rotation about a spring spool axis in first and second opposite directions, said spring spool axis being spaced apart from said belt webbing spool axis, said spring spool having an outer peripheral surface, said outer peripheral surface of said spring spool having a non-conical configuration;
- a rewind spring connected with said spring spool for biasing said spring spool for rotation in the first direction to apply retraction force to said spring spool;
- and
- an elongate flexible member extending between said outer peripheral surface of said spring spool and said outer peripheral surface of said shaft spool for transmitting retraction force from said spring spool to said shaft spool to bias said belt webbing spool for rotation in the belt retraction direction;
- said outer peripheral surface of said shaft spool having a radially undulating configuration with a radius which both increases and decreases a plurality of times over the axial length of said shaft spool.
5 more elements
A vehicle occupant safety apparatus comprising:
- a belt webbing spool supported for rotation about a belt webbing spool axis in a belt retraction direction and an opposite belt withdrawal direction;
- a length of belt webbing wound on said belt webbing spool, said belt webbing being extensible about a vehicle occupant to restrain the occupant;
- a shaft spool fixed for rotation with said belt webbing spool in the belt retraction direction and in the belt withdrawal direction, said shaft spool having an outer peripheral surface, said outer peripheral surface of said shaft spool having a non-conical configuration;
- a spring spool supported for rotation about a spring spool axis in first and second opposite directions, said spring spool axis being spaced apart from said belt webbing spool axis, said spring spool having an outer peripheral surface, said outer peripheral surface of said spring spool having a non-conical configuration;
- a rewind spring connected with said spring spool for biasing said spring spool for rotation in the first direction to apply retraction force to said spring spool;
- and
- an elongate flexible member extending between said outer peripheral surface of said spring spool and said outer peripheral surface of said shaft spool for transmitting retraction force from said spring spool to said shaft spool to bias said belt webbing spool for rotation in the belt retraction direction;
- said flexible member extending from one of a plurality of axially spaced first positions on said outer peripheral surface of said spring spool and from a corresponding one of a plurality of axially spaced second positions on said outer peripheral surface of said shaft spool;
- and
- wherein the radius of said spring spool at said one first position and the radius of said shaft spool at said corresponding one second position are determined in accordance with the equation:
- ##EQU2## where:
- a. Fr=the retraction force applied by said belt webbing spool to said belt webbing when said flexible member extends from said spring spool at said one first position;
- b. Tr=the retraction torque applied by said rewind spring to said spring spool when said flexible member extends from said spring spool at said one first position;
- c. Rp=the radius of said spring spool when said flexible member extends from said spring spool at said one first position;
- d. Rh=the radius of said shaft spool when said flexible member extends from said shaft spool at said corresponding one second position;
- e. Rw=the radius of said belt webbing spool when no belt webbing is wound on said belt webbing spool;
- f. n=the number of wraps of said belt webbing on said belt webbing spool when said flexible member extends from said spring spool at said one first position;
- g. t=the thickness of one wrap of said belt webbing;
- and
- h. f=a factor for friction.
17 more elements
A vehicle occupant safety apparatus comprising:
- a belt webbing spool supported for rotation about a belt webbing spool axis in a belt retraction direction and an opposite belt withdrawal direction;
- a length of belt webbing wound on said belt webbing spool, said belt webbing being extensible about a vehicle occupant to restrain the occupant;
- a rewind spring for biasing said belt webbing spool for rotation in the belt retraction direction to apply retraction force to said belt webbing;
- and
- means connected between said rewind spring and said belt webbing spool for applying the retraction force of said rewind spring to said belt webbing spool, said means for applying comprising:
- (a) means for applying retraction force of a first level to said belt webbing spool when said belt webbing is completely wound on said belt webbing spool;
- (b) means for reducing the retraction force applied to said belt webbing spool, upon withdrawal of belt webbing from said belt webbing spool, from the first level to a second level;
- and
- (c) means for increasing the level of the retraction force applied to said belt webbing spool from the second level to a third level as said belt webbing is fully withdrawn from said belt webbing spool;
- said means for applying the retraction force of said rewind spring to said belt webbing spool comprising:
- a shaft spool fixed for rotation with said belt webbing spool in the belt retraction direction and in the belt withdrawal direction, said shaft, spool having an outer peripheral surface;
- a spring spool supported for rotation about a spring spool axis in first and second opposite directions, said spring spool axis being spaced apart from said belt webbing spool axis, said spring spool having an outer peripheral surface;
- and
- an elongate flexible member extending between said outer peripheral surface of said spring spool and said outer peripheral surface of said shaft spool for transmitting retraction force from said spring spool to said shaft spool to bias said belt webbing spool for rotation in the belt retraction direction;
- said flexible member extending from one of a plurality of axially spaced first positions on said outer peripheral surface of said spring spool and from a corresponding one of a plurality of axially spaced second positions on said outer peripheral surface of said shaft spool;
- and
- wherein the radius of said spring spool at said one first position and the radius of said shaft spool at said corresponding one second position are determined in accordance with the equation:
- ##EQU3## where:
- a. Fr=the retraction force applied by said belt webbing spool to said belt webbing when said flexible member extends from said spring spool at said one first position;
- b. Tr=the retraction torque applied by said rewind spring to said spring spool when said flexible member extends from said spring spool at said one first position;
- c. Rp=the radius of said spring spool when said flexible member extends from said spring spool at said one first position;
- d. Rh=the radius of said shaft spool when said flexible member extends from said shaft spool at said corresponding one second position;
- e. Rw=the radius of said belt webbing spool when no belt webbing is wound on said belt webbing spool;
- f. n=the number of wraps of said belt webbing on said belt webbing spool when said flexible member extends from said spring spool at said one first position;
- g. t=the thickness of one wrap of said belt webbing;
- and
- h. f=a factor for friction.
24 more elements
A vehicle occupant safety apparatus comprising:
- a belt webbing spool supported for rotation about a belt webbing spool axis in a belt retraction direction and an opposite belt withdrawal direction;
- a length of belt webbing wound on said belt webbing spool, said belt webbing being extensible about a vehicle occupant to restrain the occupant;
- a shaft spool fixed for rotation with said belt webbing spool, said shaft spool having an outer peripheral surface;
- a spring spool supported for rotation about a spring spool axis in first and second opposite directions, said spring spool axis being spaced apart from said belt webbing spool axis, said spring spool having an outer peripheral surface;
- a rewind spring connected with said spring spool for biasing said spring spool for rotation in the first direction to apply belt retraction force to said spring spool;
- and
- an elongate flexible member extending between said outer peripheral surface of said spring spool and said outer peripheral surface of said shaft spool for transmitting belt retraction force from said spring spool to said shaft spool to bias said belt webbing spool for rotation in the belt retraction direction;
- said outer peripheral surface of one of said spools having a radially undulating configuration with a radius which both increases and decreases a plurality of times over the axial length of said one spool.
5 more elements
Dependencies are inferred from the claim text.