Pneumatic spring including an electric switch

Claim 2

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.

Claim 3

A spring as set forth in claim 1, wherein the fastening means on at least one of said members includes insulating means for insulating said at least one member from the object fastened thereto by said fastening means.

Claim 4

A spring as set forth in claim 1 wherein said insulating means includes an annular member of insulating material fastened to said cylinder member and defining at least in part said apertured end wall of the cylinder member, said annular member movably receiving said piston rod member.

Claim 5

A spring as set forth in claim 1 wherein said interrupting means includes an annular member of insulating material in said piston assembly and radially interposed between said piston rod member and the inner wall of said cylinder member so as to insulate said second contact from said inner cylinder wall.

Claim 6

The spring of claim 1, wherein said first contact is defined by a circumferential rib formed in the inner wall of said cylinder member, and said second contact comprises a generally circular conductive element having an external diameter less than the internal diameter of the cylinder member but larger than the internal diameter of said circumferential rib.

Claim 7

The spring of claim 5, wherein said interrupting means includes a generally circular, electrically insulating element in said piston assembly, the external diameter of said electrically insulating element being such as to establish a sliding engagement with the inner wall of said cylinder, said insulating element being located on the axial side of said second contact remote from the axial position of said first contact.

Claim 8

The spring of claim 5, wherein said generally circular conductive element is mounted on said piston rod for axial movement relative thereto; and said piston assembly further includes resilient means for biasing said generally circular conductive element axially towards the axial position of said first contact.

Claim 9

The spring of claim 5, wherein the improvement further comprises: a second circumferential rib formed in the inner wall of said cylinder and projecting radially into said cavity at a location spaced axially from said first circumferential rib, said second rib being electrically conductive and defining a third electrical contact; a fourth electrical contact included in said piston assembly for engagement with said second rib when said piston assembly is located at the axial position of said rib within said cavity; said first and second conductive means connect said first and second terminals to said third and fourth contacts, respectively; and said interrupting means include means for insulating said third and fourth contacts from one another when said piston assembly is moved away from the axial position of said second rib.

Claim 10

The spring of claim 8, wherein said first and third contacts are located adjacent axially opposite ends of said cavity, whereby a conductive path is established through the spring when the piston assembly is adjacent either end of said cavity.

Claim 11

A spring as set forth in claim 1, wherein said interrupting means comprises means for interrupting the engagement of said second contact element with the inner wall of the cylinder member at said at least one portion of the stroke of the piston rod member.

Claim 12

A spring as set forth in claim 10, wherein said interrupting means comprises said cylinder wall being dimensioned over the portion thereof corresponding to said at least one portion of the stroke of the piston rod to define a gap between said second contact element and the inner wall of the cylinder, said fluid occupying said gap.

Claim 13

A spring as set forth in claim 10, wherein said interrupting means comprises a lining of insulating material on the inner wall of the cylinder member at said at least one portion of the stroke of said piston rod member.

Claim 14

A spring as set forth in claim 10, wherein said at least one portion of the stroke of said piston rod member is contiguously adjacent said closed end wall of the cylinder member.

Claim 15

A spring as set forth in claim 10, wherein said at least one portion of the stroke of said piston rod member is contiguously adjacent said apertured end wall of the cylinder member.

Claim 16

A spring as set forth in claim 1, wherein said fastening means including means for permitting pivoting of the axis of the spring relative to the vertical, said interrupting means including gravity-operated switch means responsive to movement of the spring to a first angular position relative to the vertical for interrupting the electrical connection to at least one of said terminals and to movement of the spring to a second angular position relative to the vertical for establishing said at least one electrical connection.

Claim 17

A spring as set forth in claim 15, wherein said switch means is mounted on said piston rod member in said cavity and carries said second contact element.

Claim 18

A spring as set forth in claim 15, wherein said switch comprises a mercury switch.

Claim 19

The spring of claim 1, wherein said fluid is a gas.

Claim 20

The spring of claim 1, further comprising means for electrically insulating at least one of said terminals from the object to which the member carrying said one terminal is mounted.

Claim 21

The spring of claim 1, wherein said cylinder member and said piston rod member are comprised of electrically conductive material and respectively comprise said first and second conductive means.

Claim 22

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.

Claim 23

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.

Claim 24

The combination as set forth in claim 21, wherein said lighting means includes an electric lamp mounted on said cover member.