Chucks or sockets – Member applies axial force component
Reexamination Certificate
1999-07-16
2001-02-13
Bishop, Steven C. (Department: 3722)
Chucks or sockets
Member applies axial force component
C279S133000, C279S134000, C294S097000
Reexamination Certificate
active
06186517
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of centering and gripping tools for handling pieces to be fixed in position such as metal sheet and, more generally, a centering and gripping tool of at least one member comprising a guide member carried by the end of a casing, gripping members and drive means for the gripping members between a centered position in which they are retracted within the guide member and a plurality of gripping positions in which the gripping members project outside the guide member and bear on the piece.
BACKGROUND OF THE INVENTION
Known gripping tools generally comprise a hydraulic or pneumatic jack permitting actuation of a gripping member such as a gripping arm which is drivable pivotably between an active gripping position on the piece and an inactive position. Such a tool can also comprise a guide which is introduced into a passage provided in the piece to be treated, which permits correctly centering the tool on the piece.
From FR-A-2 340 798, there is known a gripping tool whose gripping arm comes into abutment against the piece to be gripped by pivotably driving this gripping arm. This pivotal driving of the gripping arm between the release position and the gripping position is obtained by an articulated linkage mounted on a rod driven in linear displacement by a jack.
This pivotal movement of the gripping arm in this type of gripping tool has the drawback that, with certain pieces to be treated, there is obtained bad gripping, for example when the surface of the piece to be treated is not perfectly flat. In this case, the gripping arm is not always correctly positioned on the piece and does not guarantee good gripping. There exists moreover the risk of deformation of the piece.
Moreover, in the case of a gripping tool provided with a guide, the contact point of the gripping arm on the piece is relatively far from the centering point of the tool on said piece, which can give rise to a certain unbalance or require a more complicated structure of the tool.
There is known from WO-A-9635547, an indexing device for a piece through a hole in the piece and comprising a sleeve having an upper surface forming an abutment for a piece, a piston mounted in the sleeve to slide under the influence of drive means between a retracted position within the sleeve and an extended position in which it projects from the upper abutment surface of the sleeve by an end portion forming an indexing pin, a restraining jaw for the piece on the upper abutment surface of the sleeve, movably mounted on the centering pin and means to control the jaw comprising a slide mounted in an axial bore of the piston and having an end forming a cam. These control means are constituted by a slide mounted in an axial bore of the piston to slide under the influence of drive means between a first position in which it ensures the locking of the jaw in its active position by means of an active portion forming a cam driving in pivotal movement the gripping jaws toward said active position, and a second position in which it releases the locking of this jaw by controlling the pivoting of the gripping jaws toward the inactive position.
The drive means comprise among other things a first return spring disposed between the piston and the sleeve to return the piston to its extended position and a second return spring disposed between the sleeve and the slide to return the slide toward its unlocking position of the jaw.
The axial movements of the piston within the sleeve and of the slide in the piston are controlled by a jack. A principal drawback of this type of device is that, in the case of accident, for example upon a cutoff of the air supply, the jack no longer operates and thus, the second return spring blocks the device in the gripping position. Accordingly, in the gripping position, it is thus not possible to free the piece thus held.
Moreover, this structure is relatively complicated and the wear, particularly expansion of the springs, can give rise to correct positioning problems of the jaws with the passage of time.
SUMMARY OF THE INVENTION
So as to overcome these drawbacks, the present invention has for its object a centering and gripping tool of at least one piece to be fixed in position and having a through-passage suitable for said tool, of the type comprising a guide member carried at the end of a casing having an upper surface forming an abutment for said piece, gripping members and drive means for the gripping members between a centered position in which the gripping members are retracted within the guide member and a plurality of gripping positions in which the gripping members project to the exterior of the guide member and bear on the piece, characterized in that the drive means are arranged to drive simultaneously pivotably and in translation said gripping members between the centered position and a gripping position.
Thus, the gripping members are correctly positioned on the piece to be fixed in the course of the step of centering carried out by the emplacement of the guide member through the through-passage which is suitable for the piece and the pivotal drive of the gripping members permits the drive to extend said gripping members outside the guide member and their lowering on opposite sides of the guide member to come into bearing against the piece to be fixed in position, the simultaneous driving in translation of said gripping members leading to the gripping of the piece to be fixed in position against the end of the casing, on the upper surface of which casing there is formed an abutment. Thus, there is ensured complete deployment of the gripping members projecting from the guide member and there is obtained a plurality of gripping positions on the piece to be secured.
Preferably, a first end of the gripping members coming into contact with the piece to be secured has abutment means, such as a finger, suitable to come into bearing against the edge of the through-passage and suitable for the piece to be fixed upon simultaneous action in pivotal movement and translation, of the gripping members from the centered position and toward a gripping position of the pieces to be fixed.
According to another preferred embodiment, the gripping members are constituted by two levers articulated about a medial axis to form a deformable X, each lever having a first end having abutment means and whose second opposite end to the abutment means is connected to the drive means such that, under the influence of said drive means, said second ends of the levers are movable in translation, toward and away from each other, the first ends of said levers being thus driven pivotably and simultaneously in translation, because of the deformation of the X formed by said levers.
Preferably, the levers are elbowed about their axis of articulation and their second end is mounted pivotably about an axle mounted movably in translation in a guide groove of the casing, the end of the links articulated on said second ends of the lever being also mounted pivotably about said axes, such that the driving in translation of the slide gives rise, by means of the links, to a driving in translation of the axles in the groove which causes the second ends of the levers to move toward or away from each other and, as a result, because of the deformation of the levers, the simultaneous driving and pivoting movement and in translation of the first ends of the levers.
In the centered position, the gripping members are retracted within the guide member which has a slot for this purpose. This slot places in communication the interior of the gripping and centering tool with the outside. In particular, it renders accessible the gripping members and the drive means. According to a preferred embodiment, the abutment means have a play such that, in the gripping position, said abutment means close the slot of the guide member thereby protecting the interior of said gripping and centering tool, in particular against spattering of solder which could enter into said tool upon working the secured piece. There is thu
Beffrieu Michel
De Bruyn Gerard
Bishop Steven C.
Michel Beffrieu
Young & Thompson
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