Shock absorbing apparatus for heavy loads

Claim 2

Energy absorbing apparatus comprising: a fluid buffer having a first, fixed, hollow part adapted to contain a hydraulic fluid and a second part mounted on the fixed part for movement relative thereto, said second part adapted to be engaged by a moving mass and to be shifted thereby relative to said first part in one direction to exert a force on the fluid therein; a fluid accumulator exterior of the buffer; means forming a first fluid flow path between said first part and said accumulator; means in said first path for defining a resistance to the increase of pressure in said first path after the pressure therein due to the force exerted by said second part on said fluid has reached a predetermined value; and means in bypassing relationship to said defining means for presenting a second fluid flow path to allow fluid directed to the accumulator along said first path to return to said first part, to thereby urge the second part in the opposite direction when the effect of the movement of said moving mass has been removed therefrom.

Claim 3

Apparatus as set forth in claim 1, wherein said defining means includes a relief valve adapted to be opened and to maintain the fluid pressure in said first part at said predetermined value for substantially all values of velocity and operative positions of said second part relative to said first part.

Claim 4

Apparatus as set forth in claim 2, wherein said valve is of the pilot-actuated type.

Claim 5

Apparatus as set forth in claim 1, wherein said buffer comprises a fluid piston and cylinder assembly.

Claim 6

Apparatus as set forth in claim 1, wherein said presenting means includes a fluid flow line having a check valve therein which permits fluid to flow only from the accumulator to said first part.

Claim 7

Apparatus as set forth in claim 1, wherein the accumulator is precharged with a fluid.

Claim 8

Apparatus as set forth in claim 1, wherein the said forming means, said defining means and the accumulator are separate from said buffer.

Claim 9

Apparatus as set forth in claim 1, wherein is included a second buffer having a first, fixed, hollow part adapted to contain a hydraulic fluid and a second part disposed in and movable relative to the first part to exert a force on the fluid therein, said first part of the second buffer being in fluid communication with said forming means.

Claim 10

Apparatus as set forth in claim 1, wherein said defining means includes a valve having a main valve portion and a pilot relief valve portion, said main valve portion being opened by fluid pressure in said first path only after said pilot relief valve portion has been opened.

Claim 11

Apparatus for absorbing the kinetic energy of a moving mass comprising: a fluid piston and cylinder assembly having means thereon for mounting the same in a support, the piston of the assembly being shiftable longitudinally of the cylinder thereof and having a shaft extending through the cylinder and projecting outwardly therefrom, the outer end of the shaft having a pad adapted to be engaged by a moving mass, the cylinder having a chamber remote from said shaft and containing a hydraulic fluid, there being a fluid passage through the cylinder in fluid communication with said chamber thereof, said piston being operable to pressurize the fluid in said chamber when a moving mass engages and moves said pad and thereby said piston in one direction; a fluid accumulator exteriorly of the assembly and adapted to be pressurized by fluid received thereby, whereby the accumulator can store energy in the form of fluid pressure; means defining a first fluid path between said fluid flow passage of the cylinder and the accumulator; a pilot-actuated relief valve disposed across said first path and being normally closed when the piston is in an initial operative position within the cylinder, said relief valve being opened when the fluid pressure in said first path has attained a predetermined value, said valve having means for maintaining the fluid pressure in said first path substantially constant for substantially all velocities and operative positions of the piston relative to the cylinder; a check valve; and means forming a second fluid flow path for coupling the check valve to the accumulator and to said fluid flow passage to permit return of fluid from the accumulator to said chamber after the piston movement in said one direction has been halted to thereby cause the piston to move in the opposite direction toward and into said initial operative position.

Claim 12

Apparatus for absorbing the kinetic energy of a moving mass comprising: a fluid piston and cylinder assembly having means thereon for mounting the same in a support, the piston of the assembly being shiftable longitudinally of the cylinder thereof and having a shaft extending through the cylinder and projecting outwardly therefrom, the outer end of the shaft having a pad adapted to be engaged by a moving mass, the cylinder having a chamber remote from said shaft and containing a hydraulic fluid, there being a fluid passage through the cylinder in fluid communication with said chamber thereof, said piston being operable to pressurize the fluid in said chamber when a moving mass engages and moves said pad and thereby said piston in one direction; a fluid accumulator exteriorly of the assembly and adapted to be pressurized by fluid received thereby, whereby the accumulator can store energy in the form of fluid pressure; means defining a first fluid path between said fluid flow passage of the cylinder and the accumulator; a pilot-actuated relief valve disposed across said first path and being normally closed when the piston is in an initial operative position within the cylinder, said relief valve being opened when the fluid pressure in said first path has attained a predetermined value, said valve having means for maintaining the fluid pressure in said first path substantially constant for substantially all velocities and operative positions of the piston relative to the cylinder; a check valve; and means forming a second fluid flow path for coupling the check valve to the accumulator and to said fluid flow passage to permit return of fluid from the accumulator to said chamber after the piston movement in said one direction has been halted to thereby cause the piston to move in the opposite direction toward and into said initial operative position.

Claim 13

Apparatus as set forth in claim 10, wherein the relief valve has a pilot relief valve portion and a main valve portion, the main valve portion being opened only after the pilot relief valve portion has been opened, and including means on the relief valve portion for biasing the same to a closed position, and means for adjusting the bias force of said bias means.

Claim 14

Apparatus as set forth in claim 10, wherein is included a fluid flow control valve device coupled to said second path in series relatinship with the check valve.