Intrascopic hydraulic cylinder

Abstract

A hydraulic cylinder (1) which acts as a cylinder hollow rod in an outer hydraulic cylinder (10) is disclosed comprising an inner rod (4) with a piston (2) and piston-gland (3) wherein the cylinder hollow rod (1) is held longitudinally displaceably in the cylinder housing (10). The system additionally has a cylinder base (5) and a fibre cover (14) on the outer casing of hydraulic cylinder (10). The system also has ports for fluid (11, 12 and 13) corresponding to four chambers, (67, 8 and 9 respectively). According to the invention, when pressure is applied to chamber (7), the internal rod (4) extends into the chamber (6), displacing its mass and dramatically increases the pressure in Chamber (6). This displacement is effectively an internal pump which can be activated multiple times within a given stroke of rod (1).

Claims

1. A hydraulic cylinder assembly comprising: an outer cylindrical housing; and an inverted hydraulic cylinder inside the outer cylindrical housing, wherein the inverted hydraulic cylinder is smaller than the outer cylindrical housing and functions as a piston-rod assembly held longitudinally displaceably within the outer cylindrical housing, and wherein the inverted hydraulic cylinder comprises a cylindrical hollow rod containing a piston, a piston-gland and an inner rod.

2. The hydraulic cylinder assembly according to claim 1, wherein the cylindrical hollow rod has a hydraulic port for the flow of fluid in its body at a top end, wherein the hydraulic port is external to the hydraulic cylinder assembly and wherein the outer cylindrical housing has an additional hydraulic port for flow of fluid near a base of the outer cylindrical housing, wherein the additional hydraulic port is internal to the hydraulic cylinder assembly.

3. The hydraulic cylinder assembly according to claim 1, wherein the cylindrical hollow rod has a further hollow rod affixed in the piston-gland, wherein the inner rod of the cylindrical hollow rod extends and retracts by sliding within the further hollow rod, and wherein, when pressure is applied to a cap end chamber of the cylindrical hollow rod, the piston of the cylindrical hollow rod forces the inner rod into a cap end chamber of the outer cylindrical housing and subsequently forces the further hollow rod into the cap end chamber of the outer cylindrical housing.

4. The hydraulic cylinder assembly according to claim 1, wherein the outer cylindrical housing has a cylinder base and a hydraulic port for the flow of fluid near the cylinder base and also has an additional hydraulic port for flow of fluid in its body, wherein both the hydraulic port and the additional hydraulic port are external to the body of the outer cylindrical housing.

5. The hydraulic cylinder assembly according to claim 1, wherein the outer cylindrical housing has a cover of fibrous material on a body of the outer cylindrical housing.

6. The hydraulic cylinder assembly according to claim 5, wherein the cover of fibrous material comprises carbon fibre or nanotube fibre.

7. The hydraulic cylinder assembly according to claim 2, wherein the cylindrical hollow rod has a further hollow rod affixed in the piston-gland, wherein the inner rod of the cylindrical hollow rod extends and retracts by sliding within the further hollow rod, and wherein, when pressure is applied to a cap end chamber of the cylindrical hollow rod, the piston of the cylindrical hollow rod forces the inner rod into a cap end chamber of the outer cylindrical housing and subsequently forces the further hollow rod into the cap end chamber of the outer cylindrical housing.

8. The hydraulic cylinder assembly according to claim 7, wherein the outer cylindrical housing has a cylinder base and a hydraulic port for the flow of fluid near the cylinder base and also has an additional hydraulic port for flow of fluid in its body, wherein both the hydraulic port and the additional hydraulic port are external to the body of the outer cylindrical housing.

9. The hydraulic cylinder assembly according to claim 8, wherein the outer cylindrical housing has a cover of fibrous material on its body.

10. The hydraulic cylinder assembly according to claim 9, wherein the cover of fibrous material comprises carbon fibre or nanotube fibre.

11. The hydraulic cylinder assembly according to claim 7, wherein the outer cylindrical housing has a cover of fibrous material on its body.

12. The hydraulic cylinder assembly according to claim 11, wherein the cover of fibrous material comprises carbon fibre or nanotube fibre.

13. The hydraulic cylinder assembly according to claim 2, wherein the outer cylindrical housing has a cylinder base and a hydraulic port for the flow of fluid near the cylinder base and also has an additional hydraulic port for flow of fluid in its body, wherein the both the hydraulic port and the additional hydraulic port are external to the body of the outer cylindrical housing.

14. The hydraulic cylinder assembly according to claim 13, wherein the outer cylindrical housing has a cover of fibrous material on its body.

15. The hydraulic cylinder assembly according to claim 2, wherein the outer cylindrical housing has a cover of fibrous material on its body.

16. The hydraulic cylinder assembly according to claim 15, wherein the cover of fibrous material comprises carbon fibre or nanotube fibre.

17. The hydraulic cylinder assembly according to claim 3, wherein the outer cylindrical housing has a cover of fibrous material on its body.

18. The hydraulic cylinder assembly according to claim 17, wherein the cover of fibrous material comprises carbon fibre or nanotube fibre.

19. The hydraulic cylinder assembly according to claim 4, wherein the outer cylindrical housing has a cover of fibrous material on its body.

20. The hydraulic cylinder assembly according to claim 19, wherein the cover of fibrous material comprises carbon fibre or nanotube fibre.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a cross-sectional view of the intrascopic hydraulic cylinder of this invention in one embodiment.

(2) FIG. 2 shows a cross-sectional view of the intrascopic hydraulic cylinder of this invention in second embodiment.

(3) FIG. 3 shows the test results of a hydraulic cylinder prototype of this invention.

(4) FIG. 4 shows the graphical representation of the test results shown in FIG. 3.

REFERENCE NUMERALS IN THE DRAWINGS

(5) 1 Cylinder Hollow Rod

(6) 2 Piston

(7) 3 Piston—Gland

(8) 4 Inner Rod

(9) 5 Cylinder Base

(10) 6 Chamber

(11) 7 Chamber

(12) 8 Chamber

(13) 9 Chamber

(14) 10 Cylinder

(15) 11 Hydraulic port

(16) 12 Hydraulic port

(17) 13 Hydraulic port

(18) 14 Fibre

(19) 15 Hollow Rod

DESCRIPTION OF EMBODIMENTS

(20) The details of preferred embodiment of this invention along with inventive steps will now be specifically described that address the issues raised in the background and prior art above. There could be several other possible embodiments of this invention deploying the key inventive steps described here and, therefore, the scope and objective of the patent are not limited.

(21) The intrascopic cylinder of this invention has been conceived as a combination of two hydraulic cylinders integrated into one whose outer casing or envelope is virtually similar to a standard cylinder. Thus, in this conception an inverted smaller hydraulic cylinder inside the outer cylinder acts like a piston-rod assembly of a conventional hydraulic cylinder. This contraption allows one to have more than two chambers (front and rear chambers) as in conventional hydraulic cylinder with attendant more number of hydraulic ports. In this contraption, when pressure is applied to one of the chambers, its internal rod would extend into the opposite chamber displacing its mass and dramatically increasing the pressure inside it. This displacement is effectively an internal pump which can be activated multiple times within a given stroke of the modified rod (i.e. inverted smaller cylinder inside the outer cylinder).

(22) The above conception is completely ‘novel’ and has not been reported, to our knowledge, anywhere before. Further, inventive features of this invention are described below by way of possible embodiments in the following examples:

EXAMPLE

(23) FIG. 1 shows one possible embodiment of this invention where smaller cylinder termed as ‘Cylinder Hollow Rod’, 1 acts like a rod of conventional hydraulic cylinder inside the outer cylinder 10 and base 5 which is more or less like an outer casing of a conventional hydraulic cylinder. The difference between this contraption and the conventional hydraulic cylinder being that the embodiment of FIG. 1 now has multiple ports for fluid, 11, 12 and 13 corresponding to four chambers, 6 & 7, 8 and 9. The rod end of the smaller inner cylinder, 1 is hollow and contains a piston, 2 a gland 3 and an internal rod 4. The outer cylinder, 10 is similar to conventional double acting cylinder. When pressure is applied to chamber 7, the internal rod 4 extends into the chamber 6, displacing its mass and dramatically increases the pressure in Chamber 6. This displacement is effectively an internal pump which can be activated multiple times within a given stroke of rod 1.

(24) By introducing pressure in to chamber 6 and then upon challenge, subsequently into chamber 7, rod 4 will displace the existing pressurized chamber 6 and increase the pressure in that chamber. The cylinder, 10 will produce more force transmitted through rod 1 than a conventional cylinder of the same bore size.

(25) By introducing pressure to chamber 7 after chamber 6 has reached its maximum force potential at system pressure or pre-determined pressure, rod 4 will displace fluid in chamber 6 increasing the pressure in chamber 6 beyond what was previously introduced by the hydraulic supply or “system pressure”. This enables the intrascopic cylinder to create forces previously not achievable within normal size envelopes and in a hydraulic system which cannot offer unlimited pressure.

(26) The concept of integrated hydraulic cylinders within each other can be practiced in many different embodiments. FIG. 2 depicts another embodiment of this invention wherein the internal rod, 4 slides inside a hollow rod, 15.

(27) In this embodiment of FIG. 2, when pressure is applied to chamber 6 and subsequently chamber 7, piston 2 forces rod 4 into chamber 6 and subsequently forces hollow rod, 15 into chamber 6 producing multiple speeds and forces.

(28) Thus, whereas the conventional hydraulic cylinders rely on pressures and flows provided by hydraulic pumps, valves and external intensifiers, the intrascopic cylinder of this invention creates its own pressure higher than what is supplied by conventional hydraulic circuits. This transforms the cylinder into a cylinder/pump.

(29) Buckling and band strength are two significant challenges in the manufacturing of hydraulic cylinders, which is overcome here in this invention by having the inner rod 1 being wide and hollow. Care is taken to see that the rod, 4 and the rear block, 5 as in FIG. 1 are such that they would not collide.

(30) Bowing, i.e. the expansion of the outer cylinder, 10 (FIG. 1) is another problem area in hydraulic cylinders, which is avoided here by an extra cover of fibrous material, i.e., carbon fibre or nanotube fibre, 14 on the outer cylinder, 10 of the intrascopic hydraulic cylinder of this invention.

BEST MODE OF PERFORMING THIS INVENTION & INDUSTRIAL APPLICABILITY

(31) In order to demonstrate the industrial applicability of this invention, a laboratory scale prototype cylinder was fabricated as per the design shown in FIG. 1. The chambers 6 and 7 of the cylinder were equipped with appropriate pressure gauges to monitor the pressure inside these chambers when fluid was allowed to go inside through the port at chamber 6 at a given outside pressure. The pressures in chambers 6 and 7 were observed with respect to the supply pressure to chamber 6 as shown in FIG. 3. FIG. 4 shows a graphical representation of the observed pressure in chamber 6 due to intrascopic augmentation of pressure in this cylinder. It can be seen that with a relatively lower pressure of about 50 bar, it is possible to achieve a pressure as large as 135 bar.