HYDRAULIC LOCKING DEVICE

Abstract: A hydraulic locking device, wherein a booster (7) having a discharge part (6) communicating with an outer peripheral side hydraulic chamber (5) is installed in a case member (2), an input port (16) feeding an input hydraulic pressure from the outside is provided in an input oil chamber (15) of the booster (7), oil filled sealingly is provided in the outer peripheral hydraulic chamber (5) and the discharge part (6), and the booster (7) is driven by the input hydraulic pressure to generate a hydraulic pressure higher then the input hydraulic pressure in the discharge part (6) and the outer peripheral hydraulic chamber (5) so as to elastically deform a thin wall tube part (4a) of a sleeve body (4) to a radially contracting direction for locking a rod, whereby the hydraulic locking device can be downsized and increased in output power, and a hydraulic pressure supply source can be downsized and depressurized.

Description: BACKGROUND TO THE INVENTION The present invention relates to the combination of a hydraulic locking device and a rod as an output member of said locking device, as described in the preamble of claim 1. Such a combination is known from document US-A- 5 722 646. In the prior art, during the cutting or the like of a workpiece, a hydraulic locking device has been used for clamping the workpiece or for supporting the workpiece by locking to a desired position. For example, Japanese Utility Model Laid-open Patent Publication 59-128902 and Japanese Utility Model Laid-open Patent Publication 6-47710 describe this type of hydraulic locking device. In Japanese Utility Model Laid-open Patent Publication 59-128902, there is described a hydraulic locking device, comprising: an approximately cylindrical case member; a hollow piston member that is slidably fitted inside the case member and that can be elastically deformed to have a smaller diameter; a rod that is slidably fitted inside this piston member and that passes through the case member. According to this hydraulic locking device, by introducing oil into the hydraulic pressure chamber that is between the case member and the piston member, there is elastic deformation of the piston member, and the piston member is pressed into contact with the rod. The piston member and the rod are locked so that there is no relative displacement in the axial direction. In Japanese Utility Model Laid-open Patent Publication 6-47710, there is described a hydraulic locking device, comprising: a hydraulic cylinder equipped with a cylinder body and a piston member that is slidably fitted inside the cylinder body; a rod that passes through the cylinder body and that has a piston member passing through it in the axial direction; an elastically deforming sleeve that is between the piston member and the rod and is fitted outside the rod and is attached to the piston member so as not to allow relative displacement in the axial direction. According to this hydraulic locking device, hydraulic pressure is introduced to the hydraulic pressure chamber formed inside the piston member and on the outer periphery of the sleeve, and the sleeve is elastically deformed. Thereupon, this sleeve is pressed into contact with the outer perimeter surface of the rod. The rod is locked to the piston member so as not to allow relative displacement. In the hydraulic locking devices described in Japanese Utility Model Laid-open Patent Publication 59-128902 and Japanese Utility Model Laid-open Patent Publication 6-47710, the sleeve, which is integral with the piston member or is separate, is elastically deformed to have a smaller diameter due to the hydraulic pressure. The rod is locked by the static frictional force that acts between this sleeve and the rod. With this construction, if the hydraulic pressure that is elastically deforming the sleeve is a low pressure, the locking force is small. In order to generate a large locking force, a large locking device is necessary. This is disadvantageous in terms of equipment costs. Or else, a high-pressure hydraulic pressure must be supplied from the hydraulic pressure supply source. The hydraulic pressure supply source becomes large, and hydraulic pressure leaks are more easily generated. This becomes expensive. US-A-5722646 discloses a combination of a hydraulic device and a rod serving as an output member therefor, and includes reference to a sleeve body outside the rod, an outer periphery hydraulic pressure chamber on the outer periphery of a thinned tube part of the sleeve body, and a hydraulic intensifier inside the case member of the hydraulic locking device, and refers to the rod being locked by driving the intensifier with input hydraulic pressure to generate in the discharge part of the hydraulic intensifier a hydraulic pressure that is higher than the said input pressure. OBJECT AND SUMMARY OF THE INVENTION The present invention provides a combination of a hydraulic locking device and a rod as defined in claim 1. Preferred embodiments are disclosed in dependent claims 2-5. An example will be described wherein the workpiece being supplied for machining is supported from underneath by the combination of a hydraulic locking device and a rod. The workpiece is supplied from above the combination of a hydraulic locking device and a rod. While the rod is in contact with this workpiece, the rod is pushed downward. When the workpiece reaches the desired height, input hydraulic pressure is supplied from the input port to the input oil chamber of the hydraulic intensifier. Thereupon, there is driving of the hydraulic intensifier, and a hydraulic pressure that is higher than the input hydraulic pressure is generated in the outer periphery hydraulic pressure chamber on the outer periphery of the sleeve and in the discharge part. Thereupon, the thinned tube part of the sleeve body is elastically deformed to a smaller diameter, and the rod is securely locked. In particular, because the hydraulic intensifier is driven by a low input hydraulic pressure and the oil, which is filled in a sealed manner in the outer periphery hydraulic pressure chamber and the discharge part, is intensified to a higher pressure than the input hydraulic pressure, a high powered locking device can be devised without making the locking device larger. The hydraulic pressure supply source can be made smaller and can have reduced pressure. The hydraulic intensifier has an annular piston member that fits outside the sleeve body. The discharge part of this hydraulic intensifier is preferably formed on the outside periphery of the thinned tube part of the sleeve body. The hydraulic intensifier can be provided inside the case member without having to increase the diameter of the case member. The space on the outer periphery of the sleeve body can be effectively used. A spring housing hole that is open on one end is formed near the shaft core of the rod. A spring bearing member is partially inserted in this spring housing hole in a manner allowing for relative displacement. This spring bearing is affixed to the bottom wall of the case member. A compression spring that is attached to the spring housing hole and that is stopped by the spring bearing member is provided. The rod is preferably elastically impelled towards the other end by this compression spring. The rod can be constantly elastically impelled towards the other end by the elastic impelling force of the compression spring. A spring housing hole that is open on one end is formed near the shaft core of the rod. A spring is housed in this spring housing hole, and a spring bearing piston member receives one end of this spring. It is preferable to have a hydraulic pressure chamber that has hydraulic pressure acting on the spring bearing piston member and that receives an external supply of hydraulic pressure. When a low input hydraulic pressure is supplied to the hydraulic pressure chamber from the input port, the spring bearing piston member slides to the other end in opposition of the impelling force of the spring, and the spring is compressed. Thereupon, the rod is shifted to the other end and contacts the workpiece that is provided on top of this device. Next, there is driving of the hydraulic intensifier, and a hydraulic pressure of higher pressure than the input pressure is generated in the outer periphery hydraulic pressure chamber and discharge part. By this, the thinned tube part of the sleeve body is elastically deformed to a smaller diameter, and the rod is securely locked. The above hydraulic intensifier preferably has a piston member housing hole formed inside the inner wall of the case member at a position separated from the sleeve body. The hydraulic intensifier preferably also has a piston member that is shiftably housed in the piston member housing hole and that has a pressure receiving part and a pressure applying part. The workpiece is in contact with the rod and is pushed. At the desired height of the workpiece, a low-pressure input hydraulic pressure from the input port is received by the pressure receiving part of the piston member. Thereupon, the piston member slides inside the piston member housing hole. The oil in the discharge part is pressurized by the pressure applying part. A hydraulic pressure of higher pressure than the input hydraulic pressure is generated in the outer periphery hydraulic pressure chamber and the discharge part. By this, the thinned tube part of the sleeve body is elastically deformed to a smaller diameter, and the rod is securely locked. The above rod is preferably provided so that it protrudes to the exterior from one end of the case member. With this combination of a hydraulic locking device and a rod, the workpiece used in machining is pressed into contact with the rod and is pushed. At the desired position, the rod is locked, and the workpiece can be securely supported by clamping and the like. The above rod is preferably provided so that it passes through the sleeve body and case member. As a result, after adjusting the rod which passes through the sleeve body and case member to the desired position, the input hydraulic pressure is supplied and the rod can be locked. The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. BRIEF DESCRIPTION OF THE FIGURES Figures 1 through 6 relate to the main embodiment of the present invention. Figure 1 is a front view with the essential parts omitted showing a usage example where the combination of a hydraulic locking device and a rod is used as a workpiece support. Figure 2 is a vertical cross-sectional diagram of the combination of a hydraulic locking device and a rod (a cross-section along line II-II of Figure 3). Figure 3 is a plan view of the combination of a hydraulic locking device and a rod. Figure 4 is a vertical cross-sectional diagram of the combination of a hydraulic locking device and a rod (cross-section along line IV-IV of Figure 5). Figure 5 is a layout drawing of the oil conduits and air conduits in the case member. Figure 6 is a cross-sectional diagram along line VI-VI of Figure 4. Figures 7 through 11 are figures relating to the first modification mode of the present invention. Figure 7 is a vertical cross-sectional figure of a combination of a hydraulic locking device and a rod (cross-section along line VII-VII of Figure 9). Figure 8 is a vertical cross-section of a combination of a hydraulic locking device and a rod. Figure 9 is a layout drawing of the oil conduit and air conduit of the case member. Figure 10 is a cross-section along line X-X of Figure 7. Figure 11 is a vertical cross-sectional diagram showing a usage example where the combination of a hydraulic locking device and a rod is used as a clamping device. Figure 12 is a vertical cross-section of a combination of a hydraulic locking device and a rod relating to the second modification mode. Figure 13 is a vertical cross-sectional diagram of a combination of a hydraulic locking device and a rod relating to the third modification mode. Figure 14 is a vertical cross-sectional diagram of the essential parts of the combination of a hydraulic locking device and a rod of the fourth modification mode. PREFERRED EMBODIMENTS OF THE PRESENT INVENTION Referring to the figures, the embodiments of the present invention will be described. The present embodiment is an example of the present invention used in a workpiece supporting device. In other words, referring to Figure 1, a combination of a hydraulic locking member 1 and a rod 3 as the output member of said hydraulic locking member device 1 of the present embodiment is a workpiece supporting device for preventing the vibration of a workpiece Wa during machining by supporting the central part of workpiece Wa from the underside. Referring to Figures 2 through 6, hydraulic locking device 1 comprises: an approximately cylindrical case member 2, formed so that from one end (the lower end) to the upper external part is open; a metal sleeve body 4; an outer periphery hydraulic pressure chamber 5; and a hydraulic intensifier 7. A flange part 2a, which is rectangular in plan view, is formed on the upper approximately one-third portion of case member 2. Furthermore, a rod housing hole 2b for rod 3 is formed in case member 2. A piston housing hole 2c that has a larger diameter than rod housing hole 2b is formed on the approximately upper half of the inside of case member 2. A ring-shaped lid 12 is removably screwed onto the upper end of case member 2 so that lid 12 covers piston housing hole 2c. Referring to Figures 2 and 4, sleeve body 4 comprises, in order from top to bottom: a fastening ring upper part 4b, a middle tube part 4d, a thinned tube part 4a, a fastening ring lower part 4c. Of these, fastening ring upper part 4b is affixed to lid part 12 of case member 2, and fastening ring lower part 4c is affixed to rod housing hole 2b of case member 2. In particular, thinned tube part 4a is constructed so that it can be elastically deformed to a smaller diameter. An annular outer periphery hydraulic pressure chamber 5 is formed on the outside of thinned tube part 4a. An annular piston member 8 that is fitted outside sleeve body 4 is housed in piston housing hole 2c. Hydraulic intensifier 7 comprises this piston member 8 and an input oil chamber 15 and a discharge part 6. Discharge part 6 is continuous with outer periphery hydraulic pressure chamber 5. Outer periphery hydraulic pressure chamber 5 and discharge part 6 are filled with oil and sealed. Referring to Figures 2 and 4, on the bottom wall of case member 2, a spring bearing member 26 is affixed to the center position of rod housing hole 2b by a bolt 27. Spring bearing member 26 is a solid cylinder with approximately 1/3 the diameter of the bottom wall of case member 2. A catching part 26a with a somewhat large outer diameter is formed at the end of spring bearing member 26. A spring housing hole 28 that is opened at one end (lower end) is formed near the shaft core of rod 3. An engaging part 28a that can engage with catching part 26a of spring bearing member 26 is formed on one end of spring housing hole 28. Spring bearing member 26 is partially and shiftably inserted in spring housing hole 3a. Inside rod 3, a screw hole 3b that is continuous with spring housing hole 28 is formed from the top to approximately 1/3 of the entire length of rod 3. An adjusting screw 29 is screwed into screw hole 3b. A compression spring 30 that is stopped by spring bearing member 26 is attached inside spring housing hole 28. Compression spring 30 has the function of elastically impelling adjusting screw 29, or in other words rod 3, towards the other end (towards the top). Furthermore, compression spring 30 is constructed so that the impelling force can be changed to the desired strength by adjusting the vertical position of adjusting screw 29. Piston member 8 of hydraulic intensifier 7 comprises an annular large diameter part 8a that is formed on approximately the top half of piston member 8 and an annular small diameter part 8b that is formed on the lower half. Large diameter part 8a and small diameter part 8b are formed coaxially. Large diameter part 8a is slidably fitted inside piston housing hole 2c and is also slidably fitted outside of sleeve body 4. Small diameter part 8b is slidably fitted inside rod housing hole 2b. Input oil chamber 15 of hydraulic intensifier 7 is demarcated by the lower surface of lid part 12, piston housing hole 2c, the upper surface of large diameter part 8a of piston member 8, and the outer perimeter surface of sleeve body 4. An input port 16 supplies input hydraulic pressure from the exterior to input oil chamber 15. Input port 16 and a connection metal fitting 17 are provided in the horizontal direction on the upper part inside case member 2. Referring to Figures 2 through 4, on the lower part of case member 2, a pair of oil passages 18 are provided symmetrically on the right and left of Figure 2 and in parallel with the axis of rod 3. Oil passages 18 fill oil into outer periphery hydraulic pressure chamber 5 and discharge part 6. A communication hole 19 that connects oil passage 18 and outer periphery hydraulic pressure chamber 5 and discharge part in the horizontal direction is formed. A ball 20 for sealing the oil after filling and a fastening machine screw 21 are removably provided on the base end of each oil passage 18. A plug 22 is provided on the base end of communication hole 19. Referring to Figures 4 through 6, case member 2 is provided with a filter, a connection metal fitting 31, a port 31a, a breathing hole 31b, a breathing passage 34a, a breathing passage 34b, and a breathing passage 36. These are used for the breathing of actuation chamber 32 and actuation chamber 33. Actuation chamber 32 is the annular space demarcated by the lower surface of large diameter part 8a of piston member 8, piston housing hole 2c, and outer perimeter surface of small diameter part 8b. Actuation chamber 33 is the annular space demarcated by the lower surface of rod 3, rod housing hole 2b, the bottom wall part of case member 2, and spring bearing member 26. Stated more concretely, at the upper part of case member 2, from a plan view, port 31a and connection metal fitting 31 are disposed in a front-back symmetric position with input port 16 (refer to Figure 5). Breathing passage 34 that communicates with port 31a is disposed in a vertical direction. Breathing passage 34 is continuous with actuation chamber 32, actuation chamber 33 via breathing passage 35, breathing passage 36 which are disposed in the horizontal direction. There are also sealing members 9-11, 13, 14, 23-25. Next, the action of the combination of hydraulic locking device 1 and rod 3 will be described. With respect to rod 3 which is protruding out by the impelling force of compression spring 30, the workpiece is placed into contact with the end of rod 3. Opposed by the force of compression spring 30, rod 3 is pushed downward. When the workpiece reaches the desired height, a low pressure input hydraulic pressure is supplied from connection metal fitting 17 to input oil chamber 15 through input port 16. Thereupon, piston member 8 of hydraulic intensifier 7 shifts downward, and a hydraulic pressure that is higher than the input hydraulic pressure is generated in outer periphery hydraulic pressure chamber 5 and discharge part 6. By this, thinned tube part 4a of sleeve body 4 is elastically deformed to a smaller diameter and is securely pressed into contact with rod 3. Rod 3 is locked by the frictional force acting between sleeve body 4 and rod 3. Stated more concretely, for example, the surface area ratio of the pressure receiving surface area of the upper surface of large diameter part 8a of piston member 8 to the pressure applying surface area of the lower surface of small diameter part 8b is set at 3:1. Thereupon, when an input hydraulic pressure of 140 kg/cm 2 is supplied to input oil chamber 15, the hydraulic pressure generated in outer periphery hydraulic pressure chamber 5 and discharge part 6 is intensified by the surface area ratio of three times to a pressure of 420 kg/cm 2 . The above surface area ratio is only one example and is not limited to 3:1, and the input hydraulic pressure is not limited to 140 kg/cm 2 . As a result, even with a heavy weight workpiece, the workpiece can be reliably supported by the combination of hydraulic locking device 1 and rod 3. Compared to the hydraulic locking devices of the prior art, a smaller and high-powered hydraulic locking device can be achieved, and miniaturization and reduced pressure of the hydraulic supply source can be achieved. Discharge part 6 of hydraulic intensifier 7 is formed on the outer periphery of thinned tube part 4a of sleeve body 4. As a result, the space on the outer periphery of sleeve body 4 is effectively used, and hydraulic intensifier 7 can be provided inside case member 2. As a result, the miniaturization of hydraulic locking device 1 can be achieved even while internalizing hydraulic intensifier 7 in hydraulic locking device 1. Rising manufacturing costs can be suppressed. Next, partial modifications of the present embodiment will be described. Elements that are the same or roughly the same as the elements in the above embodiment are given the same numerals, and detailed descriptions are omitted. 1] Combination of hydraulic locking device 1A and rod 40... (refer to Figures 7 through 10) Referring to Figures 7 and 8, hydraulic locking device 1A comprises a case member 2; a metal sleeve body 4; an outer periphery hydraulic pressure chamber 5; and a hydraulic intensifier 7. A rod housing hole 2b for rod 40 is formed in case member 2. A piston housing hole 2c that has a larger diameter than rod housing hole 2b is formed on approximately the upper half of the inside of case member 2. A ring-shaped lid 12 is removably screwed onto the upper end of case member 2 so that lid 12 covers piston housing hole 2c. The bottom end of case member 2 is closed by attaching a bottom plate member 41, and case member 2 has a construction of a tube with a bottom. Referring to Figures 7 and 8, from the bottom end of rod 40, a spring housing hole 42 with a length of approximately one half the entire length of rod 40 is formed near the shaft core of rod 40. A tubular spring housing member 58 is fitted inside spring housing hole 42. A flange 58a is formed on one end (lower end) of spring housing member 58, and spring housing member 58 is opened at one end (lower end). An opening 58b is formed on the other end (upper end) of spring housing member 58. Flange 58a is interposed and affixed between bottom plate member 41 and the lower end of case member 2. A spring bearing piston member 43 which is slidable at a specified stroke is provided on the interior of spring housing member 58. Double springs 44, 45 are housed in the interior of spring housing member 58. One end of spring 44, spring 45 is stopped by spring bearing piston member 43. The other end (upper end) of outer spring 44 is stopped by upper plate 58c of spring housing member 58. The other end of inner spring 45 passes through opening 58b and is stopped by middle wall part 40a provided near the middle of the inside of rod 40. Spring bearing member 43 comprises a large diameter part 43a and a small diameter part 43b. Large diameter part 43a is slidably inserted into spring housing member 58. Small diameter part 43b is slidably inserted into an oil hole formed on bottom plate member 41 and demarcates hydraulic pressure chamber 41a. There are sealing members 46, 47. A screw hole is formed in the axial direction of large diameter part 43a of spring bearing piston member 43. A bolt 48 that screws into this screw hole passes through the interior of double springs 44, 45 and passes through middle wall part 40a and is provided in a unitary manner with piston member 43. An opening through which the head of bolt 48 can be inserted is formed above middle wall part 40a inside rod 40. Referring to Figures 7, 9, 10, inside the wall thickness of case member 2 and in bottom plate member 41, an oil passage 49 is formed from input port 16 to hydraulic pressure chamber 41a. Oil passage 49 supplies hydraulic pressure to hydraulic pressure chamber 41a. Oil passage 49 comprises oil passage 49a - oil passage 49d. Oil passage 49a is placed in the vertical direction from input port 16 to bottom plate member 41. Oil passage 49b is placed horizontally from the bottom of oil passage 49a. Oil passage 49c is placed vertically downward from the end of oil passage 49b to inside bottom plate member 41. Oil passage 49d is placed horizontally from the end of oil passage 49c to hydraulic pressure chamber 41a. Therefore, by supplying hydraulic pressure to hydraulic pressure chamber 41a, spring bearing piston member 43 slides upwards, and the impelling force of spring 45 is transmitted to middle wall part 40a of rod 40. As a result, rod 40 is shifted to the other end and can be pressed into contact with the workpiece. An annular space is demarcated by the lower surface of large diameter part 8a of piston member 8, piston housing hole 2c, and outer perimeter surface of small diameter part 8b. Breathing holes or breathing passages for piston member 8 are formed from this annular space passing vertically downward to bottom plate member 41. During the assembly of hydraulic locking device 1A, the stroke amount of piston member 8 can be measured by inserting pins and the like into these breathing holes. The breathing holes can be used to confirm whether or not the necessary amount of oil has been enclosed in outer periphery hydraulic pressure chamber 5 and discharge part 6. These pins can be removed after assembly is completed. Next, the action of hydraulic locking device 1A will be described. Referring to Figure 7, when rod 40 is withdrawn, a low input hydraulic pressure is supplied from connection metal fitting 17 to hydraulic pressure chamber 41 a through input port 16, oil passage 49a, oil passage 49b, oil passage 49c, and oil passage 49d. Thereupon, spring bearing piston member 43 shifts to the other end in opposition to the impelling force of spring 44, spring 45, and spring 44, spring 45 are compressed. Thereupon, rod 40 shifts towards the other end and contacts the workpiece. Next, piston member 8 of hydraulic intensifier 7 slides slightly downward, and as with the above embodiment, a hydraulic pressure higher than the input hydraulic pressure is generated in the outer periphery hydraulic pressure chamber 5 and discharge part 6. By this, the thinned tube part 4a of sleeve body 4 is elastically deformed to a smaller diameter and is securely pressed into contact with rod 40, and rod 40 can be locked. 2] Combination of hydraulic locking device 1B and rod 60... (refer to Figure 12) Referring to Figure 12, a hollow rod 60 penetrates through sleeve body 4 and case member 61. The rest is the same construction as the above hydraulic locking device 1. According to hydraulic locking device 1B, the workpiece is placed below the device, and the workpiece can be securely clamped by the lower end of rod 60. Hydraulic locking device 1B can be used for devices other than workpiece supporting devices and clamping devices. For example, with respect to the long rod 60, a pair of hydraulic locking devices 1B and a hydraulic cylinder that moves each hydraulic locking device 1B along rod 60 can be provided. The pair of hydraulic locking devices 1B work cooperatively to drive the long rod 60 up and down. 3] Combination of hydraulic locking device 1C and rod 3... (refer to Figure 13) Referring to Figure 13, hydraulic locking device 1C is equipped with an approximately cylindrical case member 50 that is formed so that it is open from one end (lower end) to the upper exterior. Case member 50 is constructed by joining a vertically split upper case 51 and lower case 52. Hydraulic locking device 1B comprises upper case 51, lower case 52, sleeve body 4, outer periphery hydraulic pressure chamber 5, and a hydraulic intensifier 53. A piston member housing hole 54 is formed inside the wall thickness of lower case 52 at a position separated from sleeve body 4. Hydraulic intensifier 53 comprises piston member housing hole 54 and a piston member 55 that is movably housed in piston member housing hole 54. Piston member 55 comprises a pressure receiving part 55a and a pressure applying part 55b. The surface area ratio of the pressure receiving surface area of pressure receiving part 55a to the pressure applying surface area of pressure applying part 55b is approximately 3:1. An input port 56 and a connection metal fitting 17 are provided on upper case 51. A pair of oil passages 18 are placed in lower case 52. A communication hole 57 that horizontally connects oil passage 18 and outer periphery hydraulic pressure chamber 5 is formed on lower case 52. Pressure receiving part 55a of piston member 55 is continuous with input port 56. Pressure applying part 55b is continuous with communication hole 57 and oil passage 18. A ball 20 and a fastening machine screw member 21 are provided at the base end of each oil passage 18. Oil is filled from oil passage 18. Otherwise, ball 20, fastening machine screw 21, spring bearing member 26, compression spring 30, adjusting screw 29 and the like have the same construction as in hydraulic locking device 1. According to hydraulic locking device 1C, pressure receiving surface area of pressure receiving part 55a of piston member 55 can be set to be large with respect to the pressure applying surface area of pressure applying part 55b. As a result, the same action and advantages as the previous embodiment is achieved. 4] Combination of hydraulic locking device 1D and rod 3...(refer to Figure 14) Referring to Figure 14, hydraulic locking device 1D is one in which, for the above hydraulic locking device 1A, an air blowing mechanism 70 is provided. Air blowing mechanism 70 removes foreign substances, such as shavings from workpiece Wa, that are adhering to the surface of rod 3 by blowing air onto rod 3 from near the upper end of lid 12. This air blowing mechanism 70 comprises: an air supply unit (not shown) for supplying air to case member 2 and an air passage 71 formed on case member 2 and lid 12. The air supplied to case member 2 is led to the upper inner rim of ring-shaped lid 12 by this air passage 71, and, from there, the air is blown onto the surface of rod 3. Air passage 71 comprises: air passages 72, 73 formed on the interior of case member 2, an annular air passage 74 formed on top of sealing member 13 between case member 2 and lid 12, a plurality (four, for example) of air passages 75 formed on lid 12. Of these, air passages 75 extend diagonally upward towards the core of rod 3 from annular air passage 75. A nozzle part 76 is provided at the end of air passage 75. In addition, an air tube 77 extending from the air supply unit is connected via connection plug 77a to an air introducing port 72a on the lower end of air passage 72. According to hydraulic locking device 1D, because the above air blowing mechanism 70 is provided, any foreign substances such as shavings from workpiece Wa adhering to the surface of rod 3 can be reliably removed. In other words, because foreign substances such as shavings from workpiece Wa are prevented from entering between the surface of the advancing and retreating rod 3 and lid 12 and sleeve body 4, rod 3 can be advanced and retreated smoothly. As a result, abrasion of sliding parts of rod 3 and lid 12 and sleeve body 4 can be prevented. Next, additional description relating to the modified examples will be given. Sleeve body 4 is metallic and preferably steel. However, it is not limited to metal. For example, it can be made of FRP. In the present embodiments, the present invention was applied to combinations of a hydraulic locking device and a rod as an output member as workpiece supporting devices. However, the present invention can be similarly applied to hydraulic locking devices for various machine tools and industrial machinery. As described above, according to the hydraulic locking device of the present invention, a smaller and a higher powered hydraulic locking device compared to the hydraulic locking device of the prior art can be devised, and a hydraulic pressure supply source that is smaller and of a lower pressure can be devised. In addition, the present invention has various advantages such as the suppression of rising manufacturing costs, improved generalizability, and the like.

Claims: The combination of a hydraulic locking device (1, 1A, 1B, 1C; 1D) and a rod (3; 40; 60) as an output member of said locking device; wherein said hydraulic locking device comprises:- a sleeve body (4) fitted outside the rod and equipped with a thinned tube part (4a) that can be elastically deformed to a smaller diameter; a case member (2; 61; 50) supporting said sleeve body; an outer periphery hydraulic pressure chamber (5) formed on the outer periphery of said thinned tube part of said sleeve body; a hydraulic intensifier (7; 53) provided inside said case member and having a discharge part (6) continuous with said outer periphery hydraulic pressure chamber (5); an input port (16) for supplying input hydraulic pressure from the exterior to an input oil chamber (15) of said hydraulic intensifier (7); and oil filled in a sealed manner in said outer periphery hydraulic pressure chamber and said discharge part; said rod being locked by driving said hydraulic intensifier with said input hydraulic pressure that is supplied from said input port, and generating a hydraulic pressure that is higher than said input hydraulic pressure in said discharge part and said outer periphery hydraulic pressure chamber, and elastically deforming said thinned tube part of said sleeve body to a smaller diameter; characterised in that said hydraulic intensifier (17; 53) has an annular piston member (8; 55) fitted outside said sleeve body; and in that said discharge part of said hydraulic intensifier is formed on the outer periphery of said thinned tube part of said sleeve body. The combination of a hydraulic locking device and a rod as described in claim 1, including:- a spring housing hole (28; 42) with one end open, formed in said rod near the shaft core of said rod; a spring bearing member (26; 43) partially inserted in a shiftable manner inside said spring housing hole and affixed to a bottom wall of said case member (2); and a compression spring (30) attached to said spring housing hole and stopped by said spring bearing member; wherein said rod (3) is elastically impelled away from said open end by said compression spring. The combination of a hydraulic locking device and a rod as described in claim 1, including:- a spring housing hole (42) with one end open, formed in said rod near the shaft core of said rod; a spring (44, 45) housed in said spring housing hole and a spring bearing piston (43) that receives one end of said spring; and a hydraulic pressure chamber (41a) that actuates hydraulic pressure on said spring bearing piston member (43) and that receives a supply of hydraulic pressure from the exterior. The combination of a hydraulic locking device and a rod as described in one of claims 1 to 3, wherein: said rod (3; 40) protrudes to the exterior from one end of said case member (2). The combination of a hydraulic locking device and a rod as described in one of claims 1 to 3, wherein: said rod (3) passes through said sleeve body (4) and said case member (2).

Inventors: KAWAKAMI TAKAYUKI, KAWAKAMI, TAKAYUKI
Applicants: PASCAL ENG CORP, PASCAL ENGINEERING CORPORATION
Application year: 1999
Main classification: B23B31
IPC codes: B23Q3, F15B3, B25B5, B23B31, F15B15