Patent ID: 6993905

Claim:
A hydraulic cylinder comprising a cap part, a body part, and a base part, wherein the cap part comprises: a cap; a support part formed on an upper surface of the cap; an operation hole formed at an upper surface of the support part; a hitching member formed adjacent to the operation hole; a manipulating means; an adjusting hole formed at an upper surface of the cap; a compression hole; and an adjusting part formed at the cap; wherein the body part comprises: a body case; a compression rod inserted into a compression hole of the cap; a first piston disposed under the compression rod; a first cylinder having an inner cylinder space for sealingly receiving the first piston; a resilience member disposed adjacent to the first cylinder for biasing the first piston upwardly; a second cylinder having a substantially closed upper end; a resilience member inserted into the second cylinder; a piston member sealingly inserted into the second cylinder for pressing the resilience member; an operation rod inserted in the operation hole of the cap and having thereunder a second piston member; a third cylinder having an inner cylinder space for sealingly receiving the operation rod; an adjusting rod having a hitching groove and inserted in the adjusting hole of the cap; a control rod disposed under the adjusting rod and formed thereunder with a second adjusting groove and a first adjusting groove each spaced out at a distance; a resilience member disposed about the control rod for biasing the control rod upwardly; and a coupling part having an insertion hole for receiving the control rod therein; and wherein the base part comprises: a body; a first groove part for coupling with the first cylinder; a second groove part for coupling with the second cylinder; a third groove part for coupling with the coupling part; a fourth groove part for coupling with the third cylinder; a first check valve disposed at one lateral surface of the first groove part; a first passage formed between the first groove part and the first check valve; a second passage formed between the first groove part and the second groove part; a second check valve formed in the second passage; an oil control mechanism formed between a third passage formed between the second groove part and the third groove part and a fourth passage; and a fifth passage formed between the third groove part and a fourth groove part.