Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B5/00—Clamps
  • B25B5/06—Arrangements for positively actuating jaws
  • B25B5/12—Arrangements for positively actuating jaws using toggle links
  • B25B5/122—Arrangements for positively actuating jaws using toggle links with fluid drive

Definitions

• the present invention relates to a clamping device comprising a lever actuated hydraulically or pneumatically by a piston of the type used to hold parts to be machined or welded. It relates more particularly to a damping device fitted to the clamping device.
• clamping devices are known of the type comprising a jack controlling the pivoting of a lever arm by means of a connecting rod or of several rods, in particular the clamping devices described in the French patent applications published FR -A-2 340 798 and FR- A-2 536 323.
• Document FR-A-2 183 689 discloses such a tightening device comprising a stop, axially adjustable, in order to limit the stroke of the piston of the jack.
• the function of this stop is to ensure precise positioning of the stirrup.
• the present invention aims to remedy the aforementioned drawbacks of clamping devices by means of simple, reliable, inexpensive and which in particular allow to significantly increase the speed of positioning of the lever in the released position, the life of the clamping device, while reducing the noise nuisance it generates during its operation. It also makes it possible to avoid premature wear of the tightening device itself and of the jack controlling the device or of its piston rod. These objectives being achieved with great precision in the positioning of the lever in the released position.
• the clamping device intended to retain a construction part to be machined or welded is of the type comprising a lever mounted pivoting about an axis of rotation relative to a device body to be pivotally actuated by the displacement of the piston rod of a cylinder with a longitudinal axis between a first position called inactive release position or detent position, and a second position called active clamping position, said lever being connected to the end of the piston rod by means of control and connection means, and is characterized in that it comprises damping means external to the jack intended to absorb the shocks caused in the moving parts of the control and connection means when the piston rod returns to its detent position which corresponds to the inactive position of the clamping lever.
• the piston rod, an intermediate connecting piece or an abutment and distribution piece integral in movement with said rod at least when the latter moves close to its relaxed position has an abutment surface intended to come into abutment on a complementary bearing surface integral with the body of the device or of the jack when said jack is in the released position.
• the damping means comprise at least one damping piece intended to be compressed when the abutment surface lands on the bearing surface.
• the damping piece is fixedly arranged in a damping chamber located in the lower part of the body of the device.
• the abutment surface comprises an abutment and distribution part arranged above the damping part of the device.
• the damping piece and the distribution and stop piece each have in a transverse plane a rectangular section of substantially identical length, the width of the stop piece being greater than the width of the damping piece so that said abutment piece has laterally on the periphery of its lower face the movable abutment surface.
• the complementary bearing surface comprises at least one hollow profile disposed on the side wall (s) of a damping chamber forming the lower part of the body of the device.
• the damping means are produced using a damping material such as foam or plastic.
• the damping material has a significant anti-rebound capacity, that is to say a capacity to prevent rebound after the impact.
• the damping material is a flexible polyurethane.
• Figures 1 and 2 schematically illustrate in side view a clamping device capable of comprising damping means MA, respectively in passive and active positions.
• FIG. 3a illustrates in longitudinal section an embodiment of the device in its active position.
• Figure 3b illustrates in a view similar to Figure 3a the device in the intermediate position.
• Figure 3c shows in a view similar to Figure 3a the clamping device in passive position or relaxation position.
• Figure 4a shows in cross section the clamping device in the active position.
• Figure 4b illustrates in a view similar to Figure 4a the clamping device in the intermediate position.
• FIG 4c illustrates in a view similar to Figure 4a the clamping device in the passive position.
• the clamping device 1 comprises a clamping lever bearing the general reference 2 mounted pivoting about a transverse axis of rotation 3 on a device body 4, allowing said lever to be movable between two positions, a first position A, called inactive position for releasing the part to be welded or machined, and a second position B, called the active clamping position, as shown in FIGS. 1 and 2.
• the clamping lever 2 is pivotally actuated around its axis 3 by the displacement of the piston rod 6 of a cylinder 7 with a longitudinal axis ZZ ′ by means of control and connection means MC such as, for example, a set of pivot axes and connecting rods.
• the clamping device 1 is provided with damping means MA, said damping means being intended to absorb the shocks caused during the docking of the various moving parts of the device, in particular when the clamping lever 2 is positioned in one of its extreme positions.
• the damping means MA are advantageously intended to absorb the shocks caused by the piston rod 6 of the jack 7 when it passes to its passive position or detent position, that is to say towards its position which corresponds to the inactive position of the device clamping lever.
• the piston rod 6 carries at its upper end 8 an intermediate connecting piece 21 on which is articulated at least one connecting rod 16 around a main pivot axis 22.
• the connecting rod 16 is articulated at its other end on the clamping lever 2 and more particularly on the embedding part 13 proper of the clamping lever 2 around a secondary pivot axis 23 so as to constitute the means of control and MC connection of the device.
• the body 4 of the clamping device 1 comprises an upper part 9a inside which pivots the clamping lever 2, and a lower part 9b in which the piston rod 6 of the jack slides. that the clamping device 1 comprises means for fixing said cylinder, so as to allow adaptation to said device of several types of cylinder, as well as the easy replacement of a defective cylinder.
• the upper part 9a of the body 4 of the clamping device has the general shape of a yoke 10 which is formed by two parallel side walls 10a, 10b creating between them a slot 11 intended for the passage of the lever 2, said parallel side walls 10a, 10b, are also pierced with a transverse hole of axis XX 'in which is engaged the transverse axis of rotation 3 of the lever 2, as shown in Figures 4a, 4b and 4c.
• the control means MC proper of the device are arranged in the upper part 9a of the body 4.
• Said lever 2 comprises a lever arm 14 extending an embedding part 13 which constitutes its actuation and pivoting part on which the connecting rod 16 of the control and connecting means MC is pivotally mounted.
• the lower part 9b of the body 4 forms a first closed chamber 17, inside which slides the piston rod 6 of the clamping device 1. Note that it also forms a second chamber 40, called the damping chamber, arranged just above the cylinder 7 inside which are arranged the damping means MA.
• the lower part 9b of the body 4 thus consists of two side walls 18a, 18b respectively extending the two parallel side walls 10a, 10b of the yoke 10 as well as a rear wall 19 and a front wall 20, the rear wall advantageously extending to the slot 11 of the yoke 10.
• the lower part 9b of the clamping device 1 is mounted directly on a pneumatic or hydraulic cylinder 7 with a longitudinal axis ZZ ′, the end 8 of the piston rod 6 of which is intended to move substantially vertically between an expansion position A, illustrated in Figures 1, 3c and 4c, corresponding to the inactive position of the lever 2 and a so-called locking position B, illustrated in FIGS. 2, 3a and 4a, where the lever is in its active clamping position.
• the intermediate connecting piece 21 comprises an end wall 21c and a vertical wall 21a.
• Said vertical wall carries transversely at its upper end the main pivot axis 22 on which is mounted the connecting rod 16 which can be constituted by a double rod 16a, 16b, as shown in Figures 4a to 4c.
• Said axis 22 is provided at each of its ends with a roller or end bearing 24a, 24b, intended to be guided in its substantially vertical movement by MG guide means such as longitudinal grooves or blind lights located on the side walls 10a, 10b, 18a, 18b of the body 4 of the clamping device 1.
• the connecting rods 16a, 16b are mounted at one of their ends around the vertical wall 21a of the intermediate piece 21 and at the other of their ends around the embedding part 13 of the lever 2.
• the device comprises thus two parallel connecting rods arranged on either side of the sliding part and the embedding part of the lever.
• the links 16a, 16b and their axis 22 could be mounted directly on the end of the piston rod, for example.
• the device could comprise a single billet or several connecting rods hinged together.
• the intermediate connecting piece 21 or the piston rod 6 has a movable abutment surface intended to come to rest on a complementary bearing surface integral with the body 4 of the device, when the latter is in the inactive or detent position.
• the latter comprises a movable abutment surface 30a intended to come to bear on a complementary bearing surface 31 of the body 4, said abutment surface being disposed on a distribution piece and stop 30 integral in movement with the piston rod 6 when the latter moves close to its relaxed position, as will be described later.
• the damping means MA are arranged so as to damp the docking between the movable abutment surface 30a and the complementary bearing surface 31, said docking being thus carried out with a reduced speed compared to traditional clamping devices so to limit the shocks or to absorb a good part of them and by giving a precise position to the lever by limiting its stroke.
• the damping means MA comprise a damping piece 50 fixedly disposed inside the body 4 of the device 1 and more precisely in the damping chamber 40 located in the lower part 9b of the body 4.
• the chamber 40 has a bottom wall 70 provided with an orifice intended for the passage of the piston rod 6 and on which the damping piece 50 is arranged.
• the damping piece 50 likewise comprises an internal bore intended for sliding piston rod 6.
• the distribution and abutment piece 30 is arranged on the upper face 50a of the damping piece.
• the abutment piece 30 extends laterally beyond the damping piece 50 so as to present on the periphery of its lower face the movable abutment surface 30a. Note that this stop piece is also provided with a passage orifice intended for the sliding of the piston rod.
• the complementary bearing surface 31 is formed by a hollow profile disposed in the side walls 18a, 18b of the lower part 9b of the body 4 of the device, so that, when the device is in the active position, the surface of stop 30a is separated from said bearing surface by a height H1 called the compression height illustrated in FIGS. 3a and 4a.
• the stopper and distribution piece 30 is advantageously made of a rigid material such as metallic materials, for example. Note, moreover, that it makes it possible to distribute over the entire section of the damping piece 50 the restoring force of the piston rod which is exerted by means of the intermediate piece 21 on said piece stop 30.
• the damping means MA are advantageously obtained using a damping material such as a foam or a plastic material, for example, said material being intended to be compressed so as to reduce the speed of movement of the piston rod 6 and of the intermediate piece 21 when they reach the relaxed position of the device, that is to say to reduce the speed of approach of the stop piece and of distribution 30 on the bearing surface 31.
• a damping material such as a foam or a plastic material, for example, said material being intended to be compressed so as to reduce the speed of movement of the piston rod 6 and of the intermediate piece 21 when they reach the relaxed position of the device, that is to say to reduce the speed of approach of the stop piece and of distribution 30 on the bearing surface 31.
• the damping material has significant damping properties as well as an important capacity to prevent rebound after the shock, that is to say not to restore the energy of the shock which it absorbs immediately and brutal.
• the damping material used is advantageously a plastic material such as a polyurethane, for example, such as ALLRANE R TR 1571 sold by the company ALLRIM and which is a two-component polyurethane which can be transformed at room temperature or such as ALLRANE R RX 1425 which is a flexible polyurethane elastomer.
• the damping chamber 40 has a profile intended to allow compression and therefore lateral expansion of the damping piece 50.
• the damping piece 50 and the abutment piece 30 advantageously have in a horizontal transverse plane a rectangular profile so as to be able respectively for one to compress and for the other to slide in the chamber 40 which has, in a known manner in itself a complementary transverse profile. It goes without saying that the transverse profiles of the chamber 40 and of the abutment 30 and damping 50 parts could be circular, hexagonal or other in shape, without however departing from the claimed protective field.
• the rectangular profiles of the stopper 30 and damping pieces 50 have a length L1 which is substantially identical along a transverse axis, while the stopper piece 30 has a width L2 greater than the width L3 of the damping piece of so as to create on the periphery of its lower face the movable abutment surface 30a.
• the movable abutment surface is not constituted by a rigid part, but by the bottom wall of the intermediate connecting part, said part coming directly to cause the compression of the damping means. It goes without saying that the damping part could be arranged on the piston rod which is movable so as to slide with it, and no longer be fixedly disposed on the bottom wall 70 of the chamber 40.
• the height H2 of the damping piece, the height H1 over which the compression takes place, as well as the material used to produce it are determined and chosen in particular according to the different shock parameters.
• control and connection means of the device such as the return force of the jack, the speed of movement of the piston rod and the inertia of the masses M in movement, for example, so that the docking between the movable abutment surface and the bearing surface is effected with a low impact, that is to say with a relatively low speed of the piston rod.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Jigs For Machine Tools (AREA)
• Fluid-Damping Devices (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=9512808

Family Applications (1)

Country Status (5)

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Family Cites Families (4)

• 1997
  • 1997-10-24 FR FR9713596A patent/FR2770167B1/fr not_active Expired - Fee Related
• 1998
  • 1998-10-23 AU AU97516/98A patent/AU9751698A/en not_active Abandoned
  • 1998-10-23 WO PCT/FR1998/002276 patent/WO1999021684A1/fr not_active Application Discontinuation
  • 1998-10-23 BR BR9815218-1A patent/BR9815218A/pt not_active Application Discontinuation
  • 1998-10-23 EP EP98951545A patent/EP1024926A1/de not_active Withdrawn

Non-Patent Citations (1)

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