Buffer, particularly suitable for use in railway vehicles

Claim 1

A buffer, particularly for use in railway vehicles, comprising a cylinder means; a piston means having a piston rod and connected piston slidably mounted for reciprocable movement within said cylinder means; the periphery of said piston spaced from said cylinder means to form a gap therebetween; orifices formed to extend through said piston; said piston means movable from an at rest position to a first position upon being subjected to low load impact; said piston means movable further from said first position to a second position upon being subjected to a higher load impact; a buffer fluid partially filling said cylinder means; a gaseous medium filling the remainder of said cylinder means; the volume of said gaseous medium being at least equal to the volume of said rod when fully extended within said cylinder means; said buffer fluid having a high viscosity of 10 3 to 10 5 poise to allow uniform distribution throughout of fine bubbles of said gaseous medium that are compressible to absorb the low load impact at the first position of said piston means and prevent movement of said high viscosity fluid through said orifices and said gap; and said buffer fluid flowing through said orifices and said gap to absorb the higher load impact when said piston means moves to said second position; and means to return said piston means from said second position to said at rest position.

Claim 6

A method of absorbing a load in a railway vehicle buffer having a piston located in a cylinder that is partially filled with a silicone fluid having a viscosity of 10 3 to 10 5 poise and the remainder of said cylinder filled with a gaseous medium so that when the buffer has been in an at rest position for a substantial length of time, the fluid and the gaseous medium are completely separated, comprising moving said piston in one direction to a first position under the impact of low load to compress the fine bubbles of the gaseous medium distributed uniformly throughout said buffer fluid, said bubble compression allowing said piston to move further in said direction an amount equivalent to the volume that said bubbles are compressed; and moving said piston further in said direction to a second position under the impact of higher load and allowing said buffer fluid to pass through said piston via orifices formed therein and a gap formed between said piston and its cylinder.

Claim 7

A method of absorbing a load in a railway vehicle buffer having a piston located in a cylinder that is partially filled with a silicone fluid having a viscosity of 10 3 to 10 5 poise and the remainder of said cylinder filled with a gaseous medium so that when the buffer has been in an at rest position for a substantial length of time, the fluid and the gaseous medium are completely separated, comprising moving said piston in one direction to a first position under the impact of low load to compress the fine bubbles of the gaseous medium distributed uniformly throughout said buffer fluid, said bubble compression allowing said piston to move further in said direction an amount equivalent to the volume that said bubbles are compressed; and moving said piston further in said direction to a second position under the impact of higher load and allowing said buffer fluid to pass through said piston via orifices formed therein and a gap formed between said piston and its cylinder.