Hydraulic velocity damper
First Claim
1. A hydraulic velocity damper, comprising:
- a rotatable spindle body at least in part defining an irregularly shaped housing having at least one open end, the housing at least in part defining a chamber adapted to hold a fluid, the housing having at least one fluid passage to allow fluid to be displaced from within the chamber;
a drive screw having a head portion, the drive screw positioned within the housing;
an irregularly shaped first piston threadedly connected with the drive screw and rotatable about the drive screw;
an irregularly shaped second piston threadedly connected with the drive screw and rotatable about the drive screw; and
an end cap connected to the head portion of the drive screw and mounted to the open end of the spindle body, the end cap covering the open end.
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Accused Products
Abstract
A hydraulic velocity damper for use in a seat belt retractor system to control and limit the maximum velocity of seat belt payout during loading. The seat belt webbing payout is independent of the amount of load applied to a spindle body of the hydraulic velocity damper. In one embodiment, two pistons within an elliptical housing of a rotatable spindle body rotate about two independent drive screws. As the pistons rotate about respective drive screws, the pistons move towards each other to pressurize a hydraulic fluid within a chamber defined by the housing. At a predetermined pressure, a web covering at least one metering hole in each piston ruptures and the hydraulic fluid is positively displaced from within the chamber into an inner cavity of each piston. The rate at which the spindle body rotates is limited by the fluid displacement, regardless of the pressure within the chamber.
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Citations
17 Claims
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1. A hydraulic velocity damper, comprising:
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a rotatable spindle body at least in part defining an irregularly shaped housing having at least one open end, the housing at least in part defining a chamber adapted to hold a fluid, the housing having at least one fluid passage to allow fluid to be displaced from within the chamber;
a drive screw having a head portion, the drive screw positioned within the housing;
an irregularly shaped first piston threadedly connected with the drive screw and rotatable about the drive screw;
an irregularly shaped second piston threadedly connected with the drive screw and rotatable about the drive screw; and
an end cap connected to the head portion of the drive screw and mounted to the open end of the spindle body, the end cap covering the open end. - View Dependent Claims (2, 3)
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4. In a seat belt retractor system having a seat belt, a hydraulic velocity damper, comprising:
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a spindle body having an open end and at least in part defining an elliptical housing, the housing at least in part defining a chamber adapted to contain a fluid, the housing having at least one fluid passage to allow fluid to be displaced from within the chamber;
a drive screw having a head portion and a body section, the body section positioned within the housing, the body section having a first end portion and an opposite second end portion, one of the first and the second end portion having clockwise threads and the other of the first and the second end portion having counterclockwise threads;
an elliptical first piston threadedly connected with the first end portion of the body section, the first piston rotatable about the drive screw;
an elliptical second piston threadedly connected with the second end portion of the body section, the second piston rotatable about the drive screw; and
an end cap connected to the head portion of the drive screw and connected to the open end of the spindle body to enclose the housing.
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5. A hydraulic velocity damper, comprising:
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a spindle body having an elliptical housing with a first end portion and a second end portion, the housing at least in part defining a chamber;
a first drive screw positioned within the first end portion of the housing;
a second drive screw positioned within the second end portion of the housing, one of the first and the second drive screw having clockwise threads and the other of the first and the second drive screw having counterclockwise threads;
an elliptical first piston fitted within the housing and threadedly connected with the first drive screw, the first piston moveable with respect to a length of the first drive screw;
an elliptical second piston fitted within the housing and threadedly connected with the second drive screw, the second piston moveable with respect to a length of the second drive screw;
a first end cap mateable with a head portion of the first drive screw and connected to the first end portion of the housing;
a second end cap mateable with a head portion of the second drive screw and mounted to the second end portion of the housing; and
a hydraulic fluid contained within the chamber. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification