Fluid pressure cylinders provided with impact absorbing mechanisms

A fluid pressure cylinder comprising:

• a cylinder body having a closed space therein;
• a piston slidably accommodated in the cylinder body to divide the closed space into first and second pressure chambers;
• means for supplying fluid to each chamber such that the piston reciprocates between a first stroke end and a second stroke end by receiving fluid in one of the first and second pressure chambers;
• a rod connected to the piston, wherein the rod extends from the cylinder body;
• first and second bumper surfaces, one of the first and second bumper surfaces being fixed to the piston and the other being fixed to the cylinder such that the bumper surfaces face each other, wherein the bumper surfaces approach each other when the piston reaches the first stroke end and separate from one another when the piston moves toward the second stroke end, and wherein the bumper surface that is fixed to the cylinder limits movement of the piston and determines the position of the first stroke end;
• a cushion retainer connected to the first bumper surface;
• an elastomeric cushion located between the first and second bumper surfaces for preventing direct contact between the bumper surfaces when the piston reaches the first stroke end, the cushion including:
• a base section that is retained by the cushion retainer so that the cushion is retained in close proximity to the first bumper surface;
• a buffer section joined to the base section, the buffer section having an inner surface for contacting the first bumper surface and an outer surface, which is opposite to the inner surface, for contacting the second bumper surface, wherein the buffer section is squeezed by the first and second bumper surfaces when the piston reaches the first stoke end thereby forming a sealed fluid pocket oriented to absorb an impact of said second bumper surface, and wherein the cushion is constructed such that the buffer section takes a normal position, in which the buffer section is spaced apart from the first bumper surface, when the outer surface of the buffer section is not contacted by the second bumper surface, and wherein the buffer section is moved toward the first bumper surface against the elasticity of the cushion when the outer surface of the buffer section is contacted by the second bumper surface as the piston approaches the first stroke end, and wherein the elasticity of the cushion causes the buffer section to return to the normal position when the piston moves toward the second stroke end.

A fluid pressure cylinder comprising:

• a cylinder body having a closed space therein;
• a piston slidably accommodated in the cylinder body to divide the closed space into first and second pressure chambers;
• means for supplying fluid to each chamber such that the piston reciprocates between a first stoke end and a second stoke end by receiving fluid in one of the first and second pressure chambers;
• a rod connected to the piston, wherein the rod extends from the cylinder body;
• first and second bumper surfaces, one of the first and second bumper surfaces being fixed to the piston and the other being fixed to the cylinder such that the bumper surfaces face each other, wherein the bumper surfaces approach each other when the piston reaches the first stoke end and separate from one another when the piston moves toward the second stoke end, and wherein the bumper surface that is fixed to the cylinder limits movement of the piston and determines the position of the first stoke end;
• a cushion retainer connected to the first bumper surface;
• an elastomeric cushion located between the first and second bumper surfaces for preventing direct contact between the bumper surfaces when the piston reaches the first stoke end, the cushion including:
• a base section that is retained by the cushion retainer so that the cushion is retained in close proximity to the first bumper surface;
• a buffer section joined to the base section, the buffer section having an inner surface for contacting the first bumper surface and an outer surface which is opposite to the inner surface, for contacting the second bumper surface, wherein the buffer section is squeezed by the first and second bumper surfaces when the piston reaches the first stoke end, and wherein the cushion is constructed such that the buffer section takes a normal position, in which the buffer section is spaced apart from the first bumper surface, when the outer surface of the buffer section is not contacted by the second bumper surface, and wherein the buffer section is moved toward the first bumper surface against the elasticity of the cushion when the outer surface of the buffer section is contacted by the second bumper surface as the piston approaches the first stroke end, and wherein the elasticity of the cushion causes the buffer section to return to the normal position when the piston moves toward the second end;
• wherein the buffer section includes:
• a first section connected to the base section, wherein the first section has a thickness that increases toward the center of each cushion;
• a second portion connected to the first portion, wherein the second portion has a uniform thickness;
• and
• a third portion connected to the second portion, wherein the third portion has a thickness that decreases toward the center of each cushion.