FR2827803A1 - Gripping yoke e.g. for workpieces being machined by chip removal has jaw that is deployed, engaged and retracted by power cylinder - Google Patents

Abstract

The gripping yoke (1) consists of an upper jaw (4) that can be deployed and retracted relative to a lower thrust member (3) by means of a power cylinder. In the retracted position the jaw and thrust member lie flush with one another, while in the deployed position the jaw rotates about its axis by means of a guide rod in the power cylinder so that a workpiece can be gripped between the jaw and thrust member.

Description

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CLAMP
The present invention relates to a clamp. It relates more particularly to a clamping flange intended for positioning and holding parts during their machining by specific machining centers working by removing chips.

 Numerous types of clamps are known which are intended for blocking parts for their machining. We thus find the flanges with pivoting lever which come to enclose the part between the lever arm and a bearing surface of the flange. However, this type of flange is not suitable for this type of work due, in particular, to the absence of retraction of the support.

 In the wood sector, several solutions have been developed, in particular vacuum systems such as suction tables or vacuum tables. However, for certain machining of parts, the suction surface is too small compared to the cutting force and these vacuum systems are therefore not suitable for this type of work with wooden parts. Some manufacturers have developed pneumatic clamps mounted on suction cups.

 However, these clamps also have drawbacks related to their size, the absence of retractable support and their number necessary for maintaining the part. Thus, in order to be able to carry out certain machining operations, the user must move said vices to free the path of the tool, this sometimes requires the machine to be stopped temporarily and thus makes machining operations longer.

 The present invention aims to remedy the aforementioned drawbacks using means, simple, reliable, easy to implement and inexpensive. It offers an easy-to-use clamp that can be retracted to leave enough space for the passage of the cutting tools during machining either at the flange or at the support.

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 According to its main characteristic, the clamping flange of the invention is of the type comprising an upper jaw with a stop surface and a lower jaw with a bearing surface, said jaws being movable to move one relative to the 'other along an axis of movement under the action of biasing means, and is characterized in that it comprises a retraction device which allows one of the bearing or abutment surfaces to s' retract to move from a clamping position where it at least partially covers the other bearing or abutment surface in the direction of movement of the jaws to a free position where it no longer covers it and vice versa.

 According to another characteristic of the clamp of the invention, it is characterized in that the retraction device is implemented by the movement of the jaws under the action of the biasing means.

 According to an additional characteristic of the clamping strap of the invention, it is characterized in that the retracting device is a pivoting type device which makes it possible to pivot the upper clamp relative to the other around the 'axis of movement of the jaws.

 According to the preferred embodiment of the clamp, the biasing means comprise a secondary cylinder which moves the upper flange relative to the lower support along the axis of movement.

 According to another characteristic of the clamping flange of the invention, it is characterized in that the displacement of the upper flange takes place between a low point and a high point and in that the pivoting of the upper flange, thanks to the retracting device, is carried out during the displacement thereof in the ascending phase near the high point, and when it passes from a low rest position corresponding to the low point to a high clamping position or vice versa.

 According to the preferred embodiment of the clamp of the invention, the retraction device comprises a fixed guide and pivot rod having a propeller intended to cooperate with a dog clutch

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 drive to rotate it by half a turn when it traverses the rod and its propeller from bottom to top, said dog comprising drive notches which allow it to be secured in rotation with a drive plate secured to 'A cylinder rod which partly forms the upper flange, to obtain the pivoting of the surface of the upper flange when the retracting device is used.

 According to this embodiment, the jack rod, which carries a flange at its upper end to form the upper flange, has an internal bore whose upper part is intended to allow the passage of the guide and pivot rod and whose lower part constitutes a housing for the drive dog whose dimensions allow the dog to be positioned either in the engaged low position where its notches cooperate with the notches of the drive plate fixed to the jack rod to drive it in pivoting during the climb, either in the high position where the notches are disengaged to let the dog pivot freely while the cylinder rod descends along the guide and pivot rod.

 According to another characteristic of the clamp of the invention, it is characterized in that the biasing means comprise a main cylinder which allows the displacement of the lower support, while said lower support forms the cylinder body a secondary cylinder whose cylinder rod partially forms the upper flange and in that the retraction device is implemented automatically by the displacement of the upper flange under the action of the secondary cylinder.

 According to a complementary characteristic of the clamping flange of the invention, it is characterized in that the shape of the support and of the upper jaw flange is complementary to together constitute a circular profile centered on the axis of movement of the jaws .

 According to the preferred embodiment of the clamp of the invention, the shape of the surface of the lower support is a smaller portion of a circle than that of the abutment surface of the upper jaw.

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 Other characteristics and advantages of the invention will emerge from the description which follows with reference to the appended drawings which are given only by way of nonlimiting examples.

 Figures 1 to 9d illustrate the preferred embodiment of the clamp of the invention and its constituent elements.

 Figure 1 shows in perspective the clamp at rest.

 Figure 2 illustrates in perspective the clamp in the intermediate position before the pivoting of the upper jaw.

 Figure 3 illustrates in perspective the clamp when pivoting the upper jaw.

 Figure 4 shows in perspective the clamp in the high position after the pivoting of the upper jaw.

 Figure 5 shows in perspective the clamp in the clamping position.

 Figure 6 illustrates in cross section the clamp and its mechanism.

 FIG. 7 illustrates in perspective the cooperation of the drive means with the guide and pivot rod.

 Figures 8a to 8d schematically illustrate the clamping flange when passing from the rest position to a clamping position.

 Figures 9a to 9d schematically show the clamp when passing from the clamping position to the rest position.

 The present invention relates to a clamp bearing the general reference (1). It is more particularly intended for positioning and clamping parts (2) for their machining by specific machining centers; however, it could be used for other similar applications with minor adaptations without departing from the claimed protective field of the invention. It includes a lower support (3) provided with a lower support surface (3a)

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 and an upper jaw (4) with an upper clamping surface (4), said jaws making it possible to grip a part (2), as shown in particular in FIG. 5. In its clamping position (A), the flange (1 ) has its upper clamping surface (4a) perpendicular to its lower bearing surface (3a), while biasing means make it possible to bias them towards each other.

 According to the invention, the lower support (3) and the upper jaw (4) are movable relative to each other to move along an axis (ZZ ') called the axis of movement of the jaws under the action of the means of solicitation. It can be noted that, according to the preferred embodiment of the clamping flange, it has a rounded shape and the axis of movement (ZZ ') is its axis of revolution, the flange being preferably intended to be used standing with the axis (ZZ ') arranged vertically. One could however conceive alternative embodiments where the clamping of the jaws would no longer be effected on the height, but in a lateral manner without going outside the protective field of the invention.

 According to the invention, the clamp (1) comprises a retracting device which makes it possible to move one of the bearing or clamping surfaces (3a, 4a) of the lower support (3) and the upper jaw (4) so that it is no longer level with the other surface. Thus retracted, when the jaws move between them along the axis (ZZ '), their bearing and clamping surfaces (3a, 4a) cannot grip parts and the jaws can thus come to the rest position (B) , as illustrated in figure 1.

 According to the preferred embodiment, the retracting device is a pivoting type device which makes it possible to pivot the upper clamping surface (4a) around the axis of movement (ZZ ') of the lower support (3) and of the upper jaw (4) so that it no longer covers in the direction (ZZ ') the lower support surface (3a) of the lower support (3).

 According to the invention, the retraction device is actuated by the biasing means which manage the movement of the lower support (3) and the upper jaw (4) along the axis (ZZ '). It is thus implemented automatically during the movement of the lower support (3) and the upper jaw (4) and is therefore not managed independently of these. The biasing means are constituted by a jack (5) called jack

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 secondary, advantageously pneumatic type, which acts on the upper jaw (4) to move it relative to the lower support (3) which forms the body of this secondary cylinder. Said displacement of the upper jaw (4) advantageously takes place between a high point (C), illustrated in FIGS. 8c and 9c, and a low point (B), illustrated in FIGS. 8a and 9d, corresponding to the rest position. Note that the clamping position (A) illustrated in Figures 8d and 9a is between the high point (C) and the low point (B) in the jaw stroke (4) to an intermediate position defined according to the part (2 ) to tighten.

 According to the invention, the retraction device is actuated by the displacement of the upper jaw (4) when it is close to the high point (C) in an ascending phase, it makes it possible to rotate the clamping surface (4a ) of the jaw (4) so that it no longer covers, even partially, the bearing surface (3a) of the lower bearing (3) in the direction of movement (ZZ ') of the lower bearing (3) and the upper jaw (4).

 Note that, according to the preferred embodiment of the invention, the retraction device is a mechanical type device which is actuated or implemented only by the movement of the jaw (4) under the action of the jack ( 5) which moves it along the axis (ZZ '). It consists of a guide and pivot rod (6) which has at its upper end a propeller (7) intended to cooperate with a drive dog (8a) and its drive plate (8b) to drive in rotation an actuator rod (9) integral with said plate. The cylinder rod (9) carries at its upper end a jaw (10) which has on its lower face the upper clamping surface (4a), it forms with said jaw the upper jaw (4).

 According to the preferred embodiment of the clamp, the guide and pivot rod (6) has a rectangular section intended to guide the dog clutch (8a) which itself has a similar internal profile. The propeller (7) forms a half-turn (180), as shown in Figure 7, and causes the drive dog (8a) to turn around when it travels through it. The dog clutch (8a) is driven in longitudinal upward movement (HA) by the drive plate (8b) which is integral with the cylinder rod (9), under the action of the secondary cylinder (5). Training notches

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 (IIa, llb) make it possible to secure in rotation the plate (8b) and the dog clutch (8a) during this rise so that the turn of the dog clutch causes the same movement of the plate (8b) and therefore of the rod (9) around the guide and pivot rod (6) which is arranged along the axis of movement of the jaws (ZZ '). When the dog clutch, the plate and the upper jaw have reached the high point (C) illustrated in FIGS. 8c and 9c, the secondary cylinder causes them to descend along the guide and pivot rod (6) while the dog clutch (8a) moves away from the plate (8b) so as to disengage their notches (lla, llb), leaving the plate (8b) and the rod (9) down along the guide and pivot rod (6) under the action of the jack (5) without pivoting, while the dog clutch (8a) freely undergoes the U-turn generated by the propeller (7) of the guide and pivot rod (6) without driving the plate and the jaw in its pivoting, as shown in Figures 8c, 8d and 9c, 9d. The dog (8a) having undergone its U-turn, it returns to position on the plate (8b) with its notches in the engaged position so as to be able to be driven by said plate in translation along the rod (6) while transmitting its pivoting movement during the next upward phase.

 It can be noted that the cylinder rod (9) has an internal bore whose upper part (12) promotes the passage of the guide and pivot rod (6) and whose lower part (13) forms a housing for the dog clutch drive (8a). This housing is of sufficient size to allow the dog to take a low position where it is locked in rotation by the notches (llb) of the plate (8b) and a high position where its notches (lla) are disengaged from the notches of the plate (8b) thus allowing it to pivot freely in its housing during the descent.

 According to the embodiment illustrated in Figures 1 to 9d, the clamping flange (1) comprises a main cylinder (14) intended to allow the movement of the lower support (3) along the axis of movement (ZZ ') .

Thus, the support (3) which forms the cylinder body of the secondary cylinder (5) which manages the movement of the upper jaw (4) is also movable in the direction (ZZ ') inside the body ( 16) of main cylinder (14). The lower support (3) thus forms the piston of the main cylinder and can be retracted downwards to let the tool pass when it is no longer used. note that

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 this lower support (3) carries the guide and pivot rod (6) which allows the pivoting of the upper jaw (4).

 According to the preferred embodiment of the clamp (1) of the invention, the main and secondary cylinders (5,14) are pneumatic type cylinders whose supply is managed by a control unit according to information given by the machining center that machines the part or by sensors located on the flange. Of course, other types of motorization could be envisaged, without however departing from the protective field of the invention.

 Furthermore, it can be noted that the shape of the jaws (10, 15) of the upper jaw (4) and of the lower support (3) is complementary in order to form a circular profile centered on the axis of movement of the jaws (ZZ '), as shown in Figure 1, when in the rest position. Thus, the lower jaw has a bearing surface (3a), the shape of which is a portion of a circle smaller than the clamping surface (4a) which corresponds to the other portion of complementary circle.

 Of course, the invention is not limited to the embodiments described and shown by way of examples, but it also includes all the technical equivalents and their combinations.

Claims (10)

1. Clamp (1) comprising an upper jaw (4) with a clamping surface (4a) and a lower support (3) with a bearing surface (3a), said jaws being movable to move one relative to the other along a displacement axis (ZZ ') under the action of biasing means, characterized in that it comprises a retracting device which allows one of the bearing surfaces or clamping (3a, 4a) to retract to pass from a clamping position (A) where it at least partially covers the other bearing or abutment surface (3a) according to the direction of movement of the jaws ( ZZ ') to a free position where it no longer covers it and vice versa.  2. Clamping flange (1) according to claim 1, characterized in that the retracting device is implemented by the displacement of the upper jaw (4) and the lower support (3), under the action of means of solicitation.

\ 3. Clamping flange (l) according to any one of the preceding claims, characterized in that the retracting device is a pivoting type device which makes it possible to pivot one of the bearing or clamping surfaces ( 3a, 4a) relative to each other around the axis of movement of the jaws (ZZ ').  4. Clamping flange (1) according to any one of the preceding claims, characterized in that the biasing means comprise a secondary cylinder (5) which displaces the upper jaw (4) relative to the lower support (3) along the axis of movement (ZZ ').  5. Clamp (1) according to claims 3 and 4, characterized in that the displacement of the upper jaw (4) takes place between a low point (B) and a high point (C) and in that the pivoting of the upper jaw (4) thanks to the retracting device (DE) is carried out during the displacement of the latter in ascending phase near the high point (C), and this, that it passes from a rest position corresponding to the low point (B) at a clamping position (A) or vice versa. <Desc / Clms Page number 10>  6. Clamping flange (1) according to claim 3, characterized in that the retracting device comprises a fixed guide and pivot rod (6) having a propeller (7) intended to cooperate with a drive dog ( 8a) to rotate it by half a turn when it traverses the rod and its propeller, said dog comprising drive notches (lla, llb) which allow it to be secured in rotation with a drive plate (8b ) integral with a jack rod (9) which partially forms the upper jaw (4), in order to obtain the pivoting of the clamping surface (4a) of the upper jaw (4) when the retraction device is used .  7. Clamp (1) according to claims 5 and 6, characterized in that the jack rod (9), which carries a jaw (10) at its upper end to form the upper jaw (4), has a bore internal (12,13) whose upper part is intended to allow the passage of the guide and pivot rod (6) and whose lower part (13) constitutes a housing for the drive dog (8a) whose dimensions allow the dog to be positioned in the engaged low position where its notches (lla) cooperate with the notches (llb) of the drive plate (8b) fixed t to the jack rod (9) to drive it in pivoting and in high position where the notches (lla, llb) are disengaged to let the dog pivot freely while the cylinder rod (9) descends along the guide and pivot rod (6).  8. Clamping flange (1) according to any one of the preceding claims, characterized in that the biasing means comprise a main cylinder (14) which allows the displacement of the lower support (3), while said lower support (3) forms the cylinder body of a secondary cylinder (5) whose cylinder rod (9) partly forms the upper jaw (4) and in that the retraction device is implemented automatically by the displacement of the upper jaw (4) under the action of the secondary cylinder (5).  9. Clamp (1) according to any one of the preceding claims, characterized in that the shape of the jaws (10,15) of the lower support (3) and the upper jaw (4) is complementary for <Desc / Clms Page number 11>  together constitute a circular profile centered on the axis of displacement of the jaws (ZZ ').  10. Clamping flange (1) according to claim 9, characterized in that the shape of the bearing surface (3a) of the lower support (3) is a smaller portion of a circle than that of the clamping surface (4a) of the upper jaw (4).