Pneumatic spring including an electric switch
AssigneeStabilus GmbH
InventorsHerbert Freitag, Klaus Schnitzius
Life of this patent
Estimating the term…
Abstract
The tail gate of a station wagon carries an electric lamp for automatically illuminating the adjacent portion of the body compartment when the tail gate is open. The lamp is energized from the battery of the vehicle through a pneumatic spring which biases the tail gate toward the open position. The two fastening eyes of the spring insulate the piston rod and cylinder of the spring from the tail gate and body of the vehicle respectively. A switch sealed in the spring conductively connects the piston rod and cylinder, otherwise insulated from each other, when the spring holds the tail gate open, terminals on the piston rod and cylinder outside the cylinder cavity being connected to the battery and the lamp respectively.
Claims22
In a pneumatic spring including a cylinder member having a closed end wall and an apertured end wall and defining a sealed cavity therein, a piston rod member axially movable into and out of said cavity through said apertured end wall, a piston assembly carried by said piston rod member for axial movement within said cavity, a pressurized body of electrically nonconductive fluid within said cavity, first and second electrical contacts carried by said cylinder member and said piston rod member, respectively, within said cavity, first and second electrical terminals mounted on the cylinder member and the piston rod member, respectively, outside said cavity, first and second conductive means for connecting said first and second terminals to said first and second contacts, respectively, and first and second fastening means carried by the cylinder member and the piston rod member, respectively, outside said cavity for mounting the spring to respective objects, the improvement comprising:
- the inner wall of said cylinder member being electrically conductive and defining said first electrical contact;
- said second electrical contact comprises an electrically conductive element carried by said piston rod member and extending radially therefrom for engagement with said first electrical contact;
- means for interrupting, at least at one portion of the stroke of the piston rod member within the cylinder member, at least one of (1) the electrical connection between said first and second contacts, (2) the electrical connection between said first terminal and said first contact, and (3) the electrical connection between said second terminal and said second contact, whereby an electrical conductive path is established through the spring over a portion of the stroke of the piston rod member and is interrupted at said at least one portion thereof;
- and
- means for insulating said piston rod member from said apertured end wall of said cylinder member.
The combination of an automobile vehicle body formed with a compartment therein and with an opening connecting said compartment with the ambient atmosphere;
- a cover member pivoted to said body for angular movement about a horizontally extending axis away from a position in which said cover member closes said opening;
- electrically energizable means for lighting said compartment;
- a source of electrical current on said body;
- and a pneumatic spring having (1) a cylinder member and a piston rod member respectively secured to said body and to said cover member, said piston rod member slidably extending through an apertured end wall of said cylinder, said cylinder member defining a sealed cavity therein enclosing a body of compressed gas permanently biasing said cylinder member and said piston rod member apart and thereby biasing said cover member away from said closed position thereof, (2) first and second electrical contacts carried by said cylinder member and said piston rod member, respectively, within said cavity, (3) first and second electrical terminals mounted on the cylinder member and the piston rod member, respectively, outside said cavity, one of said terminals connected to said lighting means and the other to said electrical current cource, and (4) first and second conductive means for connecting said first and second terminals to said first and second contacts, respectively;
- wherein the improvement comprises:
- the inner wall of said cylinder member being electrically conductive and defining said first electrical contact;
- said second electrical contact comprises an electrically conductive element carried by said piston rod member and extending radially therefrom for engagement with said first electrical contact;
- means for interrupting, at least at one portion of the stroke of the piston rod member within the cylinder member, at least one of (1) the electrical connection between said first and second contacts, (2) the electrical connection between said first terminal and said first contact, and (3) the electrical connection between said second terminal and said second contact, whereby an electrical conductive path between said lighting means and said electric current source is established through the spring over a portion of the stroke of the piston rod member and is interrupted at said at least one portion thereof;
- and
- means for insulating said piston rod member from said apertured end wall of said cylinder member.
Dependencies are inferred from the claim text.