Magnet assisted liftgate strut

• US 5,120,030 A
• Filed: 05/28/1991
• Issued: 06/09/1992
• Est. Priority Date: 05/28/1991
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Nehl, Thomas W., Reynolds, Michael G., Lin, William C.
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US07/705,988
• Time in Patent Office: 378 Days
• Field of Search: 267/120, 267/64.12, 267/64.11, 267/124, 267/182, 267/170, 267/166, 267/178, 188/267, 188/300, 188/322.19, 188/322.11, 188/321.11, 280/707
• US Class Current: 267/120
• CPC Class Codes: E05C 17/30 of extensible, e.g. telescopic, construction flexible members E05C17/36 ; locking of telescopic systems in general F16B7/10; lockable telescopic gas springs F16F9/0254
• CPC Class Codes: F16F 6/00 Magnetic springs magnetic spring arrangements for the suppression of vibration in systems F16F15/03; Fluid magnetic springs , i.e. magnetic spring combined with a fluid

Abstract

A strut has a cylinder body having one end closed and a piston rod which reciprocates into and out of the cylinder body through the other end thereof defining retracted and extended positions of the strut. A magnet mounted on the piston rod operates with the other end of the cylinder body in the extended position of the strut to create a magnetic force biasing the strut to the extended position. The magnet allows the strut to move from the extended position if a force sufficient to overcome the magnetic force is applied to the strut. A second embodiment has a spring mounted to the interior of the closed end of the cylinder. A first magnet is mounted on the piston rod creating a magnetic repulsive force between the two magnets urging the magnets away from each other. The spring force urging the first magnet towards the second magnet so that the strut is urged toward the extended position.

Claims

1. In a strut having a cylinder body of ferro magnetic material having one end closed, a piston rod reciprocating into and out of the cylinder body through an other end thereof defining retracted and extended positions of the strut, the improvement comprising:

magnet means cooperating with the other end of the cylinder body in the extended position of the strut to create a magnetic attraction force biasing the strut to the extended position and the magnet means allowing the strut to move from the extended position towards the retracted position if a force sufficient to overcome the magnetic force is applied to the strut.

2. A gas strut comprising:

a cylinder body of ferro magnetic material having one end closed and an other end;

a piston rod reciprocating into and out of the cylinder body through the other end thereof defining retracted and extended positions of the strut and having a piston located within the cylinder body;

a gas under pressure in the cylinder body operating at all times against the piston of the rod to create a force to urge the strut towards the extended position; and

magnet means mounted on the piston rod and cooperating with the other end of the cylinder body in the extended position of the strut to create a magnetic attraction force biasing the strut to the extended position and the magnetic means enabling the gas strut to move from the extended position when a sufficient force is applied to overcome the force of the gas and the magnetic means to the gas strut.

3. A strut comprising:

a cylinder body having one end closed and another end;

a piston rod reciprocating into and out of the cylinder body through the other end thereof defining retracted and extended positions of the strut;

a spring with one end mounted to the closed end of the cylinder adapted to create a spring force; and

a pair of magnets with one magnet mounted on the other end of the spring and the other magnet mounted on the piston rod creating a magnetic repulsive force between the two magnets urging the magnets away from each other and the spring force urging the one magnet towards the other magnet so that the strut is urged towards the extended position and the other magnet operative with the other end of the cylinder body in the extended position of the strut to create a magnetic attraction force biasing the strut to the extended position and the magnetic means enabling the strut to move from the extended position if a sufficient force is applied to the strut to overcome the magnetic forces and the spring force.