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(11) | EP 0 177 818 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Bearing and actuating apparatus with locking means |
| (57) A locking and supporting feature is provided in actuating cylinder means (244) with
a double acting piston (270,271,286). There is an intermediate pressure responsive
locking means (82) operatively associated with the actuating cylinder and piston means
and operable to lock the same together and prevent relative movement therebetween.
Cylinder (244) and piston (273) with the interposition of liners (90) lock in an interference
fit and means (317) are provided to pressurize the annulus between the piston and
the cylinder sufficiently to release the locking effect. The actuating piston means comprise piston faces of different effective areas with the larger of said piston faces (320.321) being operatively associated with the piston extend cylinder space (304) and the smaller being associated with the retract cylinder space (308). The retract cylinder space is in communication with said locking means (82), and the extend cylinder (304) space is in communication with it through fluid transfer passage means (300-302) to permit fluid flow from the extend to the retract cylinder space whereby the introduction of fluid pressurized to a level sufficient to effect initial movement of the piston (270,271,273) into the retract cylinder space (308) but not sufflcient to release the locking means (82), and the concomi- 'tant flow of said fluid from the extend to the retract cylinder space through said fluid transfer passage means (300-302) will be effective to further pressurize the fluid in the retract cylinder space to a level to release the locking means for continued movement of the piston (273) |
[0001] This invention relates to new and improved, infinitely positionable locking and bearing apparatus, and to new and improved fluid-operated actuating apparatus incorporating the same; and the apparatus of this invention embody and provide novel and significant structural and functional improvements and advantages over the similar apparatus of United States Patent 3,150,571, commonly owned.
[0002] Although apparatus similar to those disclosed in this application are disclosed in commonly owned United States Patent 3,150,571, which United States Patent represents the most relevant prior art known to applicants, it has nonetheless been determined in accordance with the teachings of this invention that certain structural and functional aspects of those prior art apparatus are less than optimal, and that novel and significant improvements can be made therein. More specifically, it has been determined in accordance with the teachings of this invention that the cost of manufacture, operation, repair and inventory of the prior art apparatus of United States Patent 3,150,571--wherein a sleeve element acts directly upon a rod element to prevent relative movement therebeiwreen, and wherein pressurized fluid is introduced between the respective sleeve and rod elements to elastically deform the sleeve element and enable relative sleeve-rod element movement--can each be significantly reduced, while the reliability of operation, the operational life and the range of suitable applications for such prior art apparatus can each be significantly increased.
[0003] It is accordingly, an object of this invention to provide new and improved, fluid-operated infinitely positionable locking and bearing apparatus.
[0004] The invention will now be described by way of example with reference to the accompanying drawing which is a side elevational view partially broken away and in cross section of an embodiment of actuating locking and bearing apparatus constructed and operative in accordance with the teachings of our invention,
[0005] A sleeve element is indicated generally at 242 and comprises a cylinder 244. which also functions as the sleeve with regard to apparatus locking and unlocking as heretofore described, and which extends as shown into and between suitable bores provided therefor in a blind end cap 246 and a rod end cap 248. The relevant cylinder and bore surfaces are complementally threaded as indicated at 250 and 252 to secure the cylinder in the blind and rod end caps; and locknuts are provided as indicated at 254 and 256 to secure the cylinder-cap assembly. Cylinder seats are provided as respectively indicated at 258 and 264 for obvious purpose.
[0006] A rod element is indicated generally at 266, and comprises a tubular rod 268 and a tubular piston 270 which includes an enlarged piston head 271 and a tube-like portion 273 which functions as the rod with regard to apparatus locking and unlocking as heretofore described.
[0007] The rod 268 and piston 270 are interconnected as shown at complementally threaded areas 272 and 274 by a generally cylindrical connector 276 to form a functionally integral piston-connector-rod assembly. Piston to connector and rod to connector seals are provided for obvious purpose as shown at 278 and 280. A rod end is indicated at 282 and is secured as shown in the open end of rod 268 at complementally threaded areas 284. A piston seal 286 is carried as shown from the piston 270 and cooperates with the inner wall of cylinder 244 to prevent the leakage of pressurized fluid around the piston; while rod wear ring, rod seal rod scraper 288. 290 and 292 are respectively carried as shown from the rod end cap 252 to cooperate with the outer surface of rod 268 to prevent leakage of pressurized fluid from the apparatus 240.
[0008] An intermediate element is indicated generally at 294 and comprises a liner 296 which is configured, dimensioned, disposed and operable relative to cylinder or sleeve 244 and piston portion 273 s heretofore described and which to those ends, comprises liner segments as indicated at 84, 86, 88, 90 and 92, and a spacer as again indicated at 100. The spacer 100 will be seen to be carried from the piston portion 273 and to be of somewhat lesser outer diameter than the inner diameter of the cylinder or sleeve 244. As a result, the annular space or volume 104 will, in this embodiment be seen to be provided between the sleeve and the spacer.
[0009] As pressurized fluid passage 298. including orifice 300 and check valve 302. is provided to extend as shown through connector 276 to communicate. and permit fluid flow only in the direction between. the internal volume or space 304 of piston 270 and the generally annular volumes or spaces 306 and 308 which are respectively formed between the connector 276 and rod 268. and the inner wall of the cylinder or sleeve 244. A pressurized fluid relief passage 310, including relief valve 312. is provided to also extend as shown through connector 276 and further communicate. and permit fluid flow only in the direction between. volumes or spaces 308 and 306. and volume or space 304.
[0010] A rod extend port is indicated at 314 and extends as shown through blind end cap 246 into communication with internal piston volume 304. A flow control device is schematically indicated at 315 and is operatively disposed as shown relative to extend port 314. A rod retract port is indicated at 316 and extends as shown through rod end cap 248 into communication with annular volume 308. A pressure relief valve is schematically indicated at 317 and is operatively disposed as shown relative to retract port 316. The respective rod extend and retract ports are connected as indicated to a non-illustrated, suitably vatved-as for venting--source of pressurized fluid which, in the apparatus 240, functions as both the actuating and operating fluid as described in detail hereinbelow. A safety fuse or blowout plug is indicated at 318 and is operable to discharge pressurized fluid outside apparatus 240 to prevent excessive pressure build-up in volume 308.
[0011] Of particular advantage with regard to the apparatus 240 is the fact that the same are fully operable to perform both the actuating and unlocking functions through use of only two fluid ports, namely the extend port 314 and the retract port 316. Significantly, no additional port(s) are required for apparatus unlocking since, as described in detail hereinbelow, apparatus 240 functions as a pump for the internal development of unlock pressure attendant extension of rod 268. This is accomplished by providing a high ratio between the piston end area of the apparatus, namely the combined areas of connector face 320 and the annular end 321 of piston 271, and the rod end area of the apparatus, namely the cross-sectional area of annular space 308. This ratio may, for example, range between 5:1 to 10:1, The pumping action is achieved by closing off the retract port 316 with relief valve 317 set at apparatus unlock pressure during extension of rod 268. Upon extension of piston 270 and rod 268. Upon extension of piston 270 and rod 268, the actuating-operating fluid in volume 308 is pressurized to the apparatus unlock pressure, as determined by the setting of relief valve 317, thus automatically unlocking the apparatus 240 and maintaining the same unlocked until piston and rod extension cease. When this occurs. through external venting of the operating-actuating fluid, the pressure in rod end volume 308 is also vented, thus reapplying the appara. tus lock. Under these circumstances, it become clear that the effective output of the apparatus 240 is equal to actuating-operating fluid pressure as multiplied by the cross-sectional area of rod 268.
[0012] More specifically, and taking for example a situation wherein the unlock pressure of the apparatus 240 is 3200 psi. and the piston-rod end are ratio is approximately 8:1, extension of rod 268 can occur with the application of actuating-operating fluid at only approximately 1600 psi to extend port 314. This is made possible by the fact that the pressurized fluid passes freely from piston volume 308 through check valve 302 in connector 276 to in turn pressurize annular spaces 306, 308 and 104, and thus the liner 82; it being clear that as pressure in the liner increases, the apparatus locking force decreases proportionally. Thus, as soon as both the piston volume 304 and the liner 82 are pressurized to approximately 1600 psi, it may be understood that the resultant combination of extend and unlock forces will cause momentary slippage of the sleeve-liner-piston lock with attendant small initial movement of the piston 270 and rod 268 to the right As soon as this small initial movement takes place, the pressure in annular spaces 306, 308 and 104, and in the liner 82, will be rapidly increased to the 3200 psi setting of relief valve 317 by the above-described apparatus pumping action as provided by the high piston-rod end area ratio. Thus, apparatus unlocking and extension of rod 268 will occur. If rod 268 is being extended against no external load, the pressurization of the actuating-operating fluid at extend port 314 may the be reduced to approximately 400 psi, with the 8:1 piston-rod end area ratio functioning nonetheless to maintain the 3200 psi unlock pressure in the liner 82 and enable rod extension to continue. If rod 268 is being extended against an external load, maintenance of the pressurization of the actuating-operating fluid at extend port 314 at an appropriate level above 400 psi will be required.
[0013] Of course, as rod extension progresses, there will be a pressure build-up in space 308 as the enlarged piston head 271 and seal 286 move to the right and, when this pressure build-up exceeds the setting of pressure relief valve 312 in connector passage 310, the former will open to permit the return of the pressurized fluid from space 308 into piston volume 304. Should relief valve 312 fail, safety fuse or blowout plug 318 would open with resultant de-pressurization of the apparatus 240 and immediate return thereof to the locked condition.
[0014] Once the rod end 282 has reached the desired partially or fully extended position thereof, as the case may be, it will be clear that simple de-pressurization of the actuating-operating fluid through extend port 314 below the unlock level will result in the immediate re-locking of the apparatus 240, in the said desired position.
[0015] For subsequent retraction of the rod end 282, and with all of the heretofore described apparatus volumes or spaces remaining filled with the essentially de-pressurized actuating-operating fluid, it will be understood that fluid pressurization through retract port 316 to the appartus unlock level, with extend port 314 vatved open and flow control device 315 operable to meter fluid therethrough at a predetermined, controlled pressure, will result in the unlocking of the apparatus, again by pressure communication through spaces 308, 306 and 104 to and through the liner 296, and the immediately following movement of the rod- connector-piston assembly to the left as seen attendant the action of the pressurized fluid against the annular retract area provided by the enlarged piston head 271 and the piston seal 286. As this movement occurs, the fluid in the now decreasing volume between the separated piston 270 and face 322 of end cap 246 will simply be expelled by pumping through the extend port 314 and flow control device 315, with connector passage 298 acting as a pressure relief means in the event of clogging of port 314, or failure of its associated valving, to prevent excessive pressure build-up in that decreasing volume. Of course, the speed of retraction will be limited by the setting of flow control device 315 which operates on a metering out principle to maintain sufficient pressure within the apparatus 240 to in turn maintain the same unlocked. In the given 8:1 area ratio and 3200 psi unlock pressure example, flow control device 315 would be operable to maintain 400 psi in piston space 304. Again, fowout fuse 318 will function to, in any event, prevent excessive pressure build-up in annular volume 308 and its communicatd apparatus volumes. Thus, the apparatus 240 remains fail-safe under all operational conditions.
[0016] Once the rod end 282 has reached the desired, relatively retracted position thereof, it will be clear that simple de-pressurization of the operating-actuating fluid through retract port 316, with virtually concomitant closure of extend port 314 to prevent further fluid flow from the apparatus 240 and insure that the same remains essentially fluid-filled, will result in the re-kxking of the appartus in that position by the re-establishment of the sleeve-liner-rod interference tits as heretofore described.
[0017] Of additionally significant advantage with regard to the appartus 240 is that fact that the liner 82 is disposed as described between the outside diameter of piston 270 and the inside diameter of the cylinder barrel or sleeve element 242. This configuration, which may be termed a "piston lock," functions to provide the shortest possible length for the apparatus locking section--or, as seen from a different perspective, the maximum effective locking area per unit length of the apparatus 240--since the locking action is applied to the largest diametral elements of the appartatus. As a result particularly compact apparatus of the type described, with attendant particularly high resistance to side loading, are provided without sacrifice in the locking capability of those apparatus.
[0018] Manufacture of the hereindisclosed apparatus is effected in substantiate the same manner as that illustrated and described in detail with reference to Figures 11 and 12 of United States Patent 3,150,571 and this need not be repeated in detail. In this instance, however, it may be understood that the respective sleeve and liner elements would be assembled as a unit, through sleeve element expansion and use of the assembly mandrel, as described in United States Patent 3,150,571, around the rod element
[0019] The actuating, locking and bearing apparatus 240 are readily utilizable in conjunction with outrigger jacks on a high capacity hydraulic crane through the affixation of the sleeve element 242, as by use of mounting shaft 326, to the crane chassis and the attachment of rod end 78 to the jack pads thereby enabling jacking and levelling of the crane relative to its support structure throughout a virtually infinite range of crane positions. In such use, an outer tube or cover, not shown, may be secured around cylinder element 242 to provide an appropriate surface for the attachment of mounting brackets or the like, and to further protect the apparatus 240 from the environment The significant advantages provided by the best mode applications of the teachings of applicants' invention as heretofore illustrated and described include the following:
(a) The interposition of the liner between the respective sleeve and rod elements eliminates the need for grooving of the sleeve, with attendant formation of areas of stress concentration therein, to enable the requisite operating fluid flow between the rod and the sleeve. As a result, the strength and operational life of the sleeve are materially increased, while the cost of manufacture thereof is materially decreased.
(b) The interposition of the liner between the respective sleeve and rod elements enables the use of the apparatus as a readily and precisely controllable and programmable braking or deceleration device without damage to the rod or sleeve through use of readily expendable and replaceable liner materials which are less hard than either of the sleeve or rod materials.
(c) The use of the liner as above completely eliminates sleeve-rod surface contact whereby sleeve-rod wear is also eliminated with attendant material increase in operational life.
(d) The use of the liner as above enables the shifting of all of the final machining operations essentially to the sleeve, as opposed to both the rod and sleeve as heretofore required, since the liner can accept and function with a rod which is slightly "out" of tolerance. As a result, the overall cost of manufacture is further materially decreased.
(e) Machining of the operating fluid grooves is simplified and rendered materially less costly since the "softer" material of the liner is significantly more readily machinable than would be the "harder" material of the sleeve.
(f) Repair and/or overhaul of the apparatus are greatly simplified and rendered relatively inexpensive in that, in most instances, replacement of the liner will function to totally accomplish the same. In addition, repair and/or overhaul inventories, and attendant carrying charges, are greatly reduced because the same can essentially be limited to a supply of relatively standard, and readily shippable, liner segments. Also, in those instances wherein repair and/or overhaul require more than simple liner replacement, it will be clear that the same is no longer limited to the rod, but rather, may be made to either or both of the rod and sleeve as, for example, by appropriate plating of the relevant surfaces.
(g) The interposition as above of the liner between the sleeve and rod elements greatly increases the range of materials which can be employed in the manufacture of those elements and, as a result, greatly increases the range of operating fluids and operating temperatures which can be employed therewith, thereby combining to greatly increase the range of useful applications to which the apparatus can be put This range of materials for the rod would include any appropriately strong metal such as steel, stainless steel or aluminium, and a wide variety or appropriately strong plastic materials such as molded or fibreglass wound compositions, or boron. The metals could be heat treated or surface hardened or, alternatively, chrome electroless or nickel plated. The range of materials for the sleeve would again include any appropriately strong metal having, in addition, an appropriate modulus of elasticity, such as steel, stainless steel, or aluminium; or similarly characterized plastics such as fibre would or fibreglass reinforced tubing, glass wound and cross-hatched epoxies, or materials com- posities. For apparatus use attendant controlled decellera- tion as described hereinabove wherein high thermal conductivity and resistance to surface wear are likely to be required of the liner material, appropriately heat treated steel or bronze would be particularly qualified. High operational temperature applications of the apparatus could also dictate the use of ceramic liner materials. Representative operating fluids would include a wide range of petroleum, water of synthetic based hydraulic fluids, and gases such as nitrogen or air. Although apparatus operating pressures can vary widely depending upon the application to which the apparatus are put, the 3200 psi operating pressure as set forth hereinabove by way of example with regard to the apparatus 240 is a representative operating pressure.
[0020] The major advantages provided as described in detail hereinabove by the new and improved basic structural configuration and manner of operation of the apparatus 240, in addition to and independent to those provided as described by the incorporation of the liner 82 therein, can, in certain instances, warrant the fabrication of the apparatus 240 without the liner in further accordance with the teachings of our invention. In such instances, the respective extemal diameter of the piston 270 and the internal diameter of the sleeve element 244 would be carefully predetermined to create an interference fit directly therebetween in the manner illustrated and described in detail in United States Patent 3,150,571. Under these circumstances, appropriate operating fluid grooves would be formed, for example, in the inner surface of the sleeve element 244 as illustrated and described in United States Patent 3,150,571, and these grooves would, of course, communicate freely with annular spaces 308 and 306 to provide for the flow of the operating fluid to the sleeve element to expand the same within the elastic limit thereof and release the sleeve element-piston interference fit, and thus the apparatus lock, upon the pressurization of the operating fluid to a sufficient level.
(a) actuating cylinder means (244),
(b) a double acting actuating piston means (268-270) operatively disposed within said actuating cylinder means (244) and dividing the same into first and second cylinder spaces,
(c) an intermediate pressure responsive locking means (82) operatively associated with said actuating cylinder and piston means and operable to lock the same together and prevent relative movement therebetween,
(d) means (317) to pressurize said locking means to a level sufficient to release the locking eftect
(i) said actuating piston means comprise piston faces of different effective areas with the larger of said piston faces (320-321) being operatively associated with said first cylinder space and the smaller of said piston faces (308 cross-section) being operatively associated with said second cylinder space,
(ii) said second cylinder space being in communication with said locking means,
(iii) said first cylinder space being in communication with said second cylinder space through fluid transfer passage means (300-302) to permit fluid flow only from said first to said sacond cylinder spaces whereby
(iv) the introduction to said first cylinder space of fluid pressurized to a level sufficient to effect initial movement of said piston into said second cylinder space but not sufficient to release said locking means,
(v) and the concomitant flow of said fluid from said first to said second cylinder spaces through said fluid transfer passage means will be effective to further pressurize said fluid in said second cylinder space to a level sufficient to release said locking means for continued movement of said piston into said cylinder space.