US 3663027 A
A bowed web of resiliently flexible material is deflected toward a straightened condition by pressure fluid and creates a clamping force with a toggle action to lock first and second parts against relative sliding and/or rotation.
Description (OCR text may contain errors)
United States Patent Klipping May 16, 1972 541 FLUID ACTUATED CLAMP  References Cited  Inventor: James L. Klipping, Rockford, Ill. UNITED STATES PATENTS Y Y  Assignee: The Ingersoll Milling Machine Compan 2,660,074 11/1953 Wilson ..'.....279/4 Rockford, n1. 3,130,978 4/1964 Van Roojen.. ..279/4 ..27  Filed: Sept 14, 1970 3,507,507 4/1970 Tobler et al 9/4 X  Appl. No.: 71,914 Primary Examiner--Francis S. Husar Attorney-Wolfe, Hubbard, Leydig, Voit & Osann, Ltd.  'U.S.Cl. ..279/4,29/lA,82/32,
90/ll A, 308/3 A, 279/1 D ABSTRACT  Int.Cl ..B23b31/30,F16b 1/00,F16b 2/02 I f fl t n 58 FieldofSearch ..29/1.5;90/llA;308/3,3A; A web 8 ma dc med toward a straightened condition by pressure fluid and creates a clamping force with a toggle action to lock first and second parts against relative sliding and/or rotation.
21 Claims, 12 Drawing Figures PATENTEDMAY 16 I972 SHEET 1 [IF 4 sum) ACTUATED CLAMP BACKGROUND OF THEINVENTION This invention relates to a clamp for locking two parts against relative movement and, more particularly, to a fluid actuated clamp with at least oneweb-like element made of resiliently yieldable material and operable when deflected by pressure fluid to cause the clamp to exert a frictional force on one of the parts and lock the latter against movement relative to the other part. A clamp of this general type is disclosed in Kampmeir US. Pat. No. 3,034,408.
SUMMARY OF THE INVENTION The primary aim of the present invention is to provide a new and improved fluid actuated clamp of the above character which, as compared with prior clamps of the same general type, is simpler and less expensive to manufacture, is capable of being used with extremely simple and permanent seals which positively prevent the leakage of any pressure fluid from the clamp and, at the same time, is effective when actuated with a given pressure to exert a greater clamping force than prior clamps of comparable size.
A more detailed object is to achieve the foregoing through the provision of a novel clamp in which the resiliently flexible element normally is bowed intermediate its ends and, upon actuation of the clamp, is deflected toward a straightened condition by the pressure fluid to create a toggle action resulting in the application of a frictional clamping force of high magnitude against one of the parts. The flexible element coacts with the part upon which the clamp is supported to define a chamber for the pressure fluid and preferably is welded to the supporting part to make the chamber fluid-tight without the need of using sealing gaskets, O-rings and the like.
The invention also resides in the novel construction of the clamp and in its wide application for locking parts of various shapes and types against relative sliding and/or rotation.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front elevation of one embodiment of a new and improved clamp incorporating the novel features of the present invention, parts being broken away and shown in section.
FIG. 2 is a cross-section taken substantially along the line 2-2 of FIG. 1.
FIG. 3 is a sectional view ofthe clamp illustrated in FIG. 1 but showing the clamp in an actuated condition.
FIG. 4 is a view somewhat similar to FIG. 1 but showing another embodiment of the clamp.
FIG. 5 is a sectional view of the clamp illustrated in FIG. 4 but showing the clamp in an actuated condition.
FIG. 6 is a front elevation of a tool holder equipped with still another type of clamp, parts being broken away and shown in section.
FIG. 7 is a cross-section taken substantially along the line 7-7 of FIG. 6.
FIG. 8 is a view of a clamp for locking a slidable table to a bed.
FIG. 9 isa view taken along the line 9-9 of FIG. 8.
FIG. 10 is an enlarged fragmentary cross-section taken substantially along the line 10-10 of FIG. 9.
FIG. 11 is a view similar to FIG. 8 but showing a different type of clamp for locking the table to the bed.
FIG. 12 is an enlarged fragmentary cross-section taken substantially along the line 12-12 of FIG. 11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purposes of illustration, the invention is embodied in a clamping member 15 which is operable when actuated by pressure fluid to frictionally lock first and second parts 16 and 17 against relative movement. In accordance with the present invention, the clamp 15 is constructed in a novel and comparatively inexpensive manner to exert a frictional clamping force of high magnitude with a toggle action and, in addition, to coact with the particular part upon which the clamp is supported to confine the pressure fluid for actuating the clamp without need of employing conventional seals such as O-rings and gaskets for preventing leakage of the pressure fluid.
For simplicity, the first part 16 is shown in the embodiment of FIGS. 1 to 3 as being a fixed sleeve formed with a central bore 19 within which the second part 17, herein a cylindrical shaft, is telescopically received for axial sliding. The clamp 15 is anchored against bodily movement relative to the sleeve 16 and, when actuated by fluid pressure, frictionally grips the shaft 17 to prevent the latter from sliding within the sleeve.
More specifically, the clamp 15 is fitted into a counterbore 20 (FIG. 1) formed in one end of the sleeve 16 and is captivated against bodily movement within the counterbore by an end cap 2I which is anchored to the sleeve by screws 23 spaced radially outwardly from the counterbore. The clamp comprises an inner ring-like member of generally U-shaped cross-section formed by an axially extending bridge element or web 24 which spans and is joined to the inner ends or margins of a pair of radially projecting leg elements or webs 25. The axial web 24 encircles the shaft 19 and defines a central opening 26 which receives the shaft while the radial webs 25 are shaped as circular discs and lie alongside the inboard faces of the counterbore 20 and the end cap 21. Preferably, the three webs are formed integrally with one another and are made of a resiliently yieldable metal such as steel or bronze.
As shown most clearly in FIGS. 1 and 3, the outer free edges of the radial webs 25 are joined to a closure ring 27 which is telescoped into the counterbore 20 in engagement with the circumferential wall thereof, the ring encircling the free edges of the radial webs. Most desirably, the joint between the radial webs and the ring is efiected by continuous welds 29 which extend around the free edges of the webs to bond the latter to the ring. Thus, the ring closes the open side of the U defined by the webs 24 and 25 and coacts with the webs to define a chamber 30 located between the webs and sealed fluid-tight by the welds 29. A fluid conduit 31 communicates with the chamber through openings 33 in the sleeve and the ring and serves to deliver pressure fluid such as hydraulic oil into the chamber from a pressure source (not shown).
Importantly, the radial webs 25 are bowed inwardly relative to the junctions 34 of the margins of the webs 25 with the web 24 and thus form convex side walls within the chamber 30. The radial webs are formed with their bowed configuration as initially manufactured and thus the webs are normally in a bowed condition with the metal of the webs relaxed. and resiliently unstressed. In one exemplary manufacturing procedure, initially straight and comparatively thick radial webs are thinned and given a bowed, convex-concave configuration by concave and convex forming tools (not shown) which shape the inner and outer sides, respectively, of the webs.
In the normal bowed condition of the radial webs 25, the bowed portions thereof are spaced inwardly from the inner faces of the counterbore 20 and the end cap 21 as shown in FIG. 1. When the radial webs 25 are in this condition, the junctions 34 between the webs 25 and the web 24 either are spaced radially from the shaft 17 by a slight distance or else just lightly engage the shaft to permit the latter to slide within the sleeve 16. To clamp the shaft, pressure fluid is admitted into the chamber 30 and the pressure created thereby deflects the bowed radial webs 25 toward straightened conditions against the resiliency of the metal and forcesthe webs toward the inner faces of the counterbore 20 and the end cap 21 to the positions shown in FIG. 3. In order to straighten, the radial webs 25 must increase the straight line distance between their welded free edges and the junctions 34 and, as a result of such distance being increased as the webs straighten, the junctions are forced radially inwardly and against the shaft 17 by the webs with a toggle action to squeeze the shaft and lock the latter tightly to the sleeve 16. Most of the clamping force is applied at and by the junctions 34 themselves rather than along the length of the axial web 24 but the toggle action exerted on the junctions, coupled with the fact that the junctions completely encircle the shaft, results in the application to the shaft of a clamping force of, substantially higher magnitude than could be obtainedsimply by radially squeezing the axial web 24 alone into engagement with the shaft. Of course, the pressure fluid in the chamber 30, as an incident to straightening the radial webs 25, also applies a direct radial force along the length of the axial web 24 to prevent the latter web from buckling radially outwardly as a result of the toggle effect and to squeeze the axial web inwardly to assist in holding the shaft and in maintaining the shaft in a radially centered position within the sleeve. When the pressure in the chamber is released, the radial webs spring back to their normal bowed positions and the junctions 34 and the axial web 24 free the shaft for sliding within the sleeve.
From the foregoing, it will be apparent that the present invention brings to the art a new and improved fluid actuated clamp 15 which is of relatively simple construction and which is capable of exerting a comparatively high clamping force by virtue of creating a toggle action. Because the webs 24 and 25 coact with the ring 27 to form the fluid chamber 30, the latter is self-contained within the clamp itself and is sealed tightly by the welds 29 to avoid the need of using conventional gaskets with their inherent relatively poor service life and reliability factors and to avoid the need for precisely machining the clamp to form seats for such gaskets. In addition, the webs and the ring may be installed in and removed from the sleeve 17 as a unit if replacement or repair are necessary.
A modified clamp 15' is shown in FIGS. 4 and 5 and is particularly suitable for locking a shaft 17 within a sleeve 16' which must be formed with a comparatively small outside diameter because of limitations in the space in which the sleeve is to be mounted. As before, the clamp is captivated within a counterbore 20' by an end cap 21' and is formed with radial webs 25 and an integral axial web 24 which define a U, the free edges of the radial webs 25' being welded to a ring 27 as indicated at 29'. In this instance, however, the axial web 24' is bowed away from the shaft 17 and is bowed inwardly relative to the junctions 34' between the webs. The radial webs 25 are comparatively short and include straight sections 35 (FIG. 4) extending along the inner faces of the counterbore 20' and the end cap 21' and joined to inclined sections 36 which merge with the axial web 24 at'the junctions 34'. The inclined sections 36 flare away from one another and outwardly from thejunctions 34'.
When the clamp is in a released condition, the axial web 24 is fully bowed and the junctions 34' are located axially along the shaft 17' in the positions shown in FIG. 4. Upon the admission of pressure The fluid into the chamber 30', the bowed axial web 24 is deflected toward a straightened condition as shown in FIG. 5 and is flexed toward the shaft to cause the junctions 34 to move away from one another along the shaft. The inner portions of the inclined sections 36 of the radial webs 25 are shifted axially along the shaft with the junctions 34', and the inclined sections thus are forced to straighten or assume more nearly radially extending positions as they move closer to the faces of the counterbore and the end cap 21'. As a result, the inclined sections 36 tend to increase the radial spacing between the ring 27' and the junctions 34 and thus force the junctions radially inwardly with a toggle action so that the junctions become tightly clamped against the shaft'l7'. As their inner portions are moved along the shaft, the inclined sections 36 hinge slightly relative to the straight sections 35 and thus may straighten without exerting stressesof high magnitude on the welds 29.
Still another clamp 40 is shown in FIG. 6 and is used for clamping a tool shank 41 in a tool holder 43 formed with a bore 44 for receiving the shank. The clamp is fitted within a counterbore 45 formed in one end of the tool holder and is captivated therein by an end cap 46.
The clamp functions on the same principle asthe clamp 15 shown in FIGS. 1 to 3 but includes only a single bowed radial web 47 extending along the inner face of the end cap 46 and formed integrally with a straight axial web 49 which encircles and extends along the shank 41. Around its free edge, the axial web 49 is welded to the tool holder 43 at the junction of the bore 44 and the counterbore as indicated at 50 in FIG. 6. The free end portion of the radial web 47 is formed with a flange 51 sandwiched between the end cap 46 and the end of the tool holder 43 and sealed by a weld 53 which serves to anchor the end cap to the tool holder. Thus, the webs 47 and 49 coact with the walls of the counterbore 45 to define a fluidtight chamber 54 between the webs and within the counterbore.
Pressure fluid is introduced into the chamber 54 through a port 55 which communicates with a fluid-filled chamber 56 located at one end of an elongated hole 57 (FIG. 7) formed in the tool holder 43. A piston 59 (FIG. 7) is disposed within the chamber 56 and is carried on the inner end of a screw 60 which is threaded into the hole 57. By manually turning the screw 60 to advance the piston 59, the fluid in the chamber 56 is forced into the chamber 54 to deflect the bowed web 47 toward a straightened condition and to toggle the junction 61 (FIG. 6) between the webs 47 and 49 into clamping engagement with the shank 41 to prevent the latter from sliding within the bore 44 and also from rotating within the bore. When the screw is turned in the opposite direction, the pressure in the chamber 54 is reduced and thus the web 47 springs back to its bowed condition to enable removal of the shankfrom the bore.
FIGS. 8 to 10 show a clamp 65 for locking two comparatively flat parts66 and 67 against relative sliding. For example, the first part 66 may be a machine tool slide or table which is movable along a second part 67 in the form of an elongated way on a fixed bed 69, The table 66 interflts with the way 67 in a conventional manner and includes a lower block 70 (FIG. 8) which rides along the underside of the way. Anti-friction liners 71 ride along the remaining sides of the way and include mounting flanges 73 which are fastened to the ends of the table by screws 74.
The clamp 65 is captivated within an elongated slot 75 (FIGS. 9 and 10) extending along the lower block 70 and opening out of the upper side of the block. In this instance, the clamp includes an elongated horizontal web 76 (FIG. 10) formed integrally with the upper ends of two generally vertical webs 77, the three webs coacting to define an elongated channel of U-shaped cross-section. An elongated closure or cap 79 is welded at 80 to the lower free edges of the vertical webs 77 and extends along the latter to close the lower side of the channel 'whileend caps 81 (FIG. 9) are welded to the end of the elongated cap and to the extreme ends of the horizontal web and the vertical webs to close the ends of the channel. One of the end caps is formed with an opening 83 through which pressure fluid may be admitted into a chamber 84 defined between the webs.
As shown in FIG. 10, the horizontal web 76 is substantially flat and extends along the lower side of the way 67, a layer 85 of anti-friction material being'bonded to the upper side of the horizontal web to reduce sliding friction between the web and the way. The vertical webs 77 are bowed inwardly relative to their junctions 86 with the horizontal web 76 and thus, when pressure fluid is admitted into the chamber 84, the vertical webs are deflected toward straightened conditions to force the junctions upwardly with a toggle action and into clamping engagement with the way 67 to lock the table 66 tightly against the way to prevent sliding of the table. Advantageously, as the liners 71 wear away during normal service use, fluid at low pressure may be maintained continuously in the chamber 84 to actuate the clamp 65 just enough to take up the wear clearance between the liners and the way 67 while still permitting free sliding of the table 66 along the way except at those times when the clamp is fully actuated by high pressure. Thus, the clamp 65 may be used to compensate for wear as well as to lock the table tightly against sliding.
A modified clamp 65 for locking a table 66 to a way 67 is shown in FIGS. 11 and 12. In this embodiment, the clamp is shaped as a cup of U-shaped cross-section and includes a flat horizontal web 76 of circular shape forming the bottom wall of the cup. The side walls of the cup are formed by a vertically extending annular web 77 formed integrally at its lower margin with the horizontal web 76' and bowed inwardly relative to the junction 86' between the webs. A circular closure disc 90 is welded to the upper edges of the vertical web 77 at 80' and includes an opening 83' for admitting pressure fluid into a chamber 84 defined between the webs.
As shown, the cup-shaped clamp 65' is disposed within a hole 91 of circular cross-section formed in the table 66 and is retained therein by a cap 93 which is connected to the table by screws 94. The horizontal web 76' is disposed in engagement with the upper liner 71 on the table 66' and thus, when pressure fluid is admitted into the chamber 84, the vertical web 77 is straightened to force the junction 86' downwardly against the liner 71' with a toggle action. Accordingly, the upper liner 71' is forced downwardly, deflecting relative to its mounting flanges 73 and mounting screws 74', and clamps against the way 67' to prevent sliding of the table 66. if desired, several of the cup-shaped clamps 65' may be disposed in holes spaced along the table to clamp the way at spaced locations along its upper surface.
1. A clamp comprising a member having first and second mutually transverse elements joined together at their adjacent margins, means coacting with the elements and secured and sealed at least to the free end portion of said first element to define a fluid-tight chamber between the elements, at least one of said elements being made of resiliently yieldable material and being bowed inwardly to form a convex wall within said chamber, and means for introducing pressure fluid into said chamber to deflect said bowed element outwardly of said chamber and toward astraightened condition against the resiliency of said material to exert force on the junction between the adjacent margins of the elements with a toggle action and in a direction tending to shift said junction and the free end portion of said first element away from one another.
2. A clamp as defined in claim 1 in which said member is of generally L-shaped cross-section with the elements forming the legs ofthe L.
3. A clamp as defined in claim 2 in which said elements are integral with one another, said second element defining a ring and said first element projecting radially from said ring around the circumference of the ring.
4. A clamp as defined in claim 1 in which said member is of generally U-shaped cross-section with said second element forming the bridge of the U.
5. A clamp comprising a member of generally U-shaped cross-section having leg elements and having a bridge element joined to and spanning the leg elements, a closure covering the open side of the U, means fastening said closure to the free end portions of said leg elements and establishing a fluid-tight seal along the entire joint between the closure and the leg elements whereby the closure and the leg and bridge elements coact to define a chamber, at least one of said elements being made of resiliently yieldable material and being bowed inwardly to form a convex wall within said chamber, and means for introducing pressure fluid into said chamber to deflect said bowed element outwardly of said chamber and toward a straightened condition against the resiliency of said material to exert force on the junction between such element and the adjacent element with a toggle action and in a direction tending to shift said junction and said closure away from one another.
6. A clamp as defined in claim 5 in which said bridge element and said leg elements are integral with one another and are formed from a single piece of resiliently yieldable material.
7. A clamp as defined in claim 6 in which said fastening means comprise welds bonding and sealing said closure to the free ends of said leg elements.
8. A clamp as defined in claim 5 in which said bridge element is made of resiliently yieldable material and is bowed inwardly.
9. A clamp as defined in claim 8 in which said leg elements also are made of resiliently yieldable material and normally flare away from one another.
10. A clamp as defined in claim 5 in which both of said leg elements are made of resiliently yieldable material and are both bowed inwardly.
11. A clamp as defined in claim 5 in which said member is ring-like with said bridge element defining a ring and with said leg elements projecting radially from opposite margins of said bridge element.
12. A clamp as defined in claim 11 in which said closure is a ring welded to the free end portions of said leg elements.
13. A clamp as defined in claim 5 in which said member is a cup with said leg elements forming the side walls of the cup and with said bridge element forming the bottom wall of the cup.
14. A clamp as defined in claim 13 in which said closure comprises a circular disc welded to the free end portions of the leg elements.
15. A clamp as defined in claim 5 in which said member is an elongated channel with said leg elements forming the sides of the channel and with said bridge element forming the bottom of the channel, and further including means fastened to said elements and said closure for closing the ends of said channel.
16. The combination of, first and second parts and a clamp for selectively locking the parts against relative movement, said clamp being captivated against bodily movement relative to said first part and comprising a pair of mutually transverse elements connected together at their adjacent margins, at least one of said elements being made of resiliently yieldable material and being bowed inwardly relative to the junction between the adjacent margins of the elements, the bowed portion of said bowed element being spaced from the adjacent one of said parts when said clamp is released and freeing said parts for relative movement, said elements coacting with one another to define two walls of a chamber disposed between the elements, and means for selectively introducing pressure fluid into said chamber to deflect said bowed element toward a straightened condition and toward the adjacent one of said parts against the resiliency of said material and thereby exert force on said junction with a toggle action to clamp the parts against relative movement.
17. The combination defined in claim 16 in which said elements define a cup, said bowed element being annular and forming the wall of the cup and the other element forming the bottom of the cup, and a weld extending continuously around the free edge portion of said bowed element and anchoring and sealing the bowed element relative to said first part.
18. The combination defined in claim 16 in which said parts are telescoped with one another, one of said elements being a ring extending circumferentially around and axially along said parts and the other of said elements extending circumferentially around and projecting radially of said ring, and means for sealing the free edge of said radially projecting element to said first part.
19. The combination defined in claim 18 in which said first part is a tool holder and in which said second part is a tool shank telescoped into said holder, the free edges of both of said elements being anchored and sealed to said tool holder by welding.
20. The combination defined in claim 16 in which one of said parts is a way and in which the other of said parts is a member slidable along said way.
21. A clamp for selectively locking first and second adjacent parts against relative movement, said clamp comprising a pair of mutually transverse webs of resiliently yieldable material joined together at their adjacent ends, said webs being supported on said first part with one of the webs being welded at its free end portion to said first part, the other of said webs and straightened condition against the resiliency of said material and thereby change the distance between said junction and the welded end portion of the welded web with a toggle action to force said junction toward the second part and clamp the parts against relative movement.