PREHENSION DEVICE FOR SHELLS

The technical field of the invention is that of gripping devices for shells and in particular for large caliber shells.

In order to handle large caliber shells (diameter greater than 80 millimeters) in a simple and rapid manner, it is known from patent FR3041622 to use a shell clamp comprising a pair of jaws intended to grip a shell, each jaw pivoting between an open position and a closed position about a pivot axis parallel to the longitudinal axis of the shell, the pivot axis of each jaw being located between a lower end and an upper end of the jaw, the end upper end of each jaw allowing the closure of the jaw by resting this upper end on a shell to be grasped.

According to this patent, the upper end of each jaw has a notch intended to interfere with a lug of a cam to keep the jaws in the closed position.

The closed position of the jaws is therefore directly linked to the relative geometries of the cam and of the jaw.

The cam is integral with a pivoting pallet, the pivoting of which, which is caused by pressing on a zone close to a stretcher, makes it possible to rotate the cam and thus free the lug from the rotating path of the notch of the jaw which has the effect of freeing the opening of the jaw.

According to this patent the gripping of a shell is done at its base on the one hand and at its warhead on the other hand. The geometries of the jaws and of their cam are therefore defined as a function of the dimensions of these parts of the shell.

If one wishes to handle shells of a different type and therefore of different length, the geometries of the jaws will not be adapted and therefore the bad grip s risks causing accidents.

The invention provides a unique device for handling shells of varying lengths and ensures a more secure grip of the shell being transported.

The invention relates to a gripping device for shells, comprising at least one pair of jaws intended to grip a shell, each jaw pivoting between an open position and a closed position about a pivot axis parallel to the longitudinal axis. of the shell, the pivot axis of each jaw being integral with a frame and located between a lower end and an upper end of the jaw, the application of the upper end of each jaw on the shell causing the closing of the jaws, device characterized in that it comprises a locking means connecting the upper ends of the jaws and comprising two connecting rods and a central segment connecting these connecting rods,connecting rods articulated with respect to the jaws by a first articulation and articulated by a second articulation to the central segment, an elastic return means connecting each first articulation at a so-called central point disposed in the middle of the central segment, device comprising at least one movable stop integral with 'an operating lever, a stop located above the locking means and adapted to push the locking means downwards to below an unstable equilibrium position of the locking means.stopper located above the locking means and adapted to push the locking means downwards to below an unstable equilibrium position of the locking means.stopper located above the locking means and adapted to push the locking means downwards to below an unstable equilibrium position of the locking means.

Advantageously, the device comprises at least two pairs of coaxial jaws.

Advantageously, the device comprises two stops each comprising a lever, each stop being intended to press on one of the connecting rods of the locking means.

Advantageously, the frame comprises a sliding support intended to interfere with an upper part of the shell in order to wedge the shell in the device.

Advantageously, the device comprises at least one wedge in its rear part which is intended to come to bear on a rear face of the base of the shell in order to position the latter longitudinally relative to the device.

Advantageously, each lever may be integral with two stops, each stop being intended to act on a connecting rod associated with a different pair of jaws.

The invention will be better understood on reading the following description, description given in the light of the accompanying drawings, drawings in which:

FIG. 1 represents a three-quarter perspective view of a device according to the invention containing a shell.

Figure 2 shows a partial cross-sectional view along the offset parallel sectional plane AA shown in Figure 1.

FIGS. 3a, 3b and 3c represent schematic views of a device according to the invention during three successive stages of grasping a shell.

Figures 4a, 4b and 4c show schematic views of a device according to the invention during three successive stages of releasing a shell.

FIGS. 5a, 5b and 5c represent detailed schematic views of a locking means fitted to a device according to the invention when the jaws of the device are closed.

According to Figure 1, a shell gripping device 1 intended to be hung at the end of a manipulator arm (arm not shown) comprises a frame 2 which comprises two pairs of jaws 10. Each pair of jaws 10 is intended to grip a shell 100 at the level of a cylindrical portion of its body. Each jaw 10 is pivotally mounted between an open position and a closed position by virtue of a pivot pin 11 located between a lower end 10a and an upper end of the jaw 10.

As seen in Figure 2, the upper ends

10b of the jaws 10 are interconnected in pairs by a locking means 30.

This locking means 30, detailed in Figures 5a, 5b, 5c, comprises a central segment 13, each of the ends of which carries a connecting rod 14 which is connected to an upper end 10b of a jaw 10.

The connecting rods 14 are articulated with respect to the jaws 10 at the levels of first articulations 16 and with respect to the central segment 13 at the level of second articulations 61.

It will be noted that FIG. 2 is a view in section along two parallel planes. So :

the left part of FIG. 2 shows the device cut at the level of the axis 11 of the jaw situated towards the rear of the shell and behind this jaw 10, which makes it possible to visualize a connecting rod 14;

- the right part of figure 2 shows the device cut behind the part of the frame 2 supporting the axis 11 of the jaw 10 located towards the front of the shell, which makes it possible to visualize a tension spring 15 and its central attachment point 13b.

Elastic return means 15, in this case tension springs 15, connect the first articulations 16 to a point called the central point 13b of the central segment 13. This central point 13b is located longitudinally in the middle of the central segment 13, below of a horizontal line L passing through each of the joints 16 and 61 when the connecting rods 14 are aligned according to FIG. 5c.

Thus, according to Figures 3a to 3c, to take hold of a shell 100, the device 1 is lowered onto the shell 100 with the jaws 10 in the open position. The upper end 10b of each jaw 10 is placed to rest on the shell 100.

In this position, the locking means 30 is in the configuration shown in FIG. 5a. The springs 15 exert a force which tends to bring the first articulations 16 closer to the central point 13b and therefore to move the second articulation 61 downwards, which opens the jaws 10 and maintains them in this open position.

According to FIG. 3b, the support and the descent of the device 1 on the shell 100 causes the jaws 10 to pivot about their axes 11 towards the closed position and 1 'clamping of the shell 100. During this phase, the ends upper 10b of the jaws 10 move away from each other.

The locking device 30 passes through an unstable equilibrium position illustrated in FIG. 5b where the first 16 and the second 61 joints of each link 14 align with the central point 13b. Each straight line connecting a first articulation 16 and a second articulation 61 is parallel to the tensile force of the spring 15 considered, which constitutes an unstable position for the locking means 30. In this position, the tensile force supplied by each spring is at its maximum.

By continuing the closing movement of the jaws 10, the connecting rods 14 will gradually turn until they are aligned (FIG. 5c). As mentioned previously, it is noted that once the connecting rods 10 are aligned, the central point 13b of the central segment 13 is located below a horizontal line L passing through each of the joints 16 and 61, this makes it possible to force the crossing of the unstable equilibrium position by the second articulations 61. The jaws 10 are then in their most closed position. Once the unstable equilibrium position of FIG. 5b has been passed, the springs 15 have the effect of bringing the connecting rods 14 closer to position 5c which corresponds to the maximum closing of the jaws 10.

To stop the movement of the connecting rods 14, a stop 17 placed above the locking means 30 (also visible in FIG. 2) blocks the rise of the second articulations 61 by interfering with the connecting rods 14 or the central segment 13.

The shell 100 is then blocked by the jaws 10 as can be seen in FIG. 3c.

To release the shell 100, the device 1 is brought over a stretcher 200 according to FIG. 4a. The stretcher is similar to that described by patent FR3041622 and has on either side of support elements 19 called buffers 19 which are intended to interfere with the levers 18 of the device 1, pivoting relative to the frame 2 around it. 'axes 20 and integral with the stops 17 (see also Figures 1 and 2).

By lowering the device 1 carrying the shell 100, as in FIG. 4b, the interference of the buffers 19 will cause the pivoting of the levers 18 which will push the stops 17 against the connecting rods 14 until the second joints 61 pass through. below the unstable equilibrium position defined above, which causes the rapid opening of the jaws 10 (driven by the springs 15), as visible in FIG. 4c, and the removal of the shell 100 in the stretcher 200.

The jaws 10 are then locked in the open position by the simple pulling action of the springs 15. The device 1 is ready to go and grab a new shell.

It can therefore be seen that the device according to the invention can be adapted to the maintenance of shells having substantially different dimensions, the locking position being obtainable for pivoting of the different jaws. The main thing is to make the locking means 30 pass beyond its unstable equilibrium position. In this case the springs 15 ensure the locking of the jaws. The stiffness of the springs 15 will be chosen to be sufficient to prevent any return of the locking means 30 to the shell release position during vibrations (FIG. 3a).

As shown in Figures 4a to 4c, the device 1 may include a sliding support 60 capable of being pushed back by a spring 67 through the frame 2 and against the upper part of a shell in order to wedge it when it is clamped in the device 1 by application of a vertical force, to combat accelerations on all axes.

It is noted in Figure 1, that the frame 2 comprises a pair of wedges 32 intended to come to rest on a rear face of the base 105 of the shell 100 in order to position the shell 100 longitudinally relative to the device 1. The frame 2 also comprises on each side of the clamping elements 33 (only one is visible in FIG. 1) intended to limit the pivoting of the levers 18 and therefore the downward stroke of the associated stops 17. It will also be noted that according to the embodiment of FIG. 1, each lever 18 is integral with two stops 17 each intended to act on a locking means associated with a different pair of jaws. Thus the levers 18 are located longitudinally midway between the pairs of jaws 10 (Figure 1).
CLAIMS

1- Gripping device (1) for shells (100), comprising at least one pair of jaws (10) intended to grip a shell (100), each jaw (10) pivoting between an open position and a closed position around it 'a pivot axis (11) parallel to the longitudinal axis of the shell (100), the pivot axis (11) of each jaw (10) being integral with a frame and located between a lower end (10a ) and an upper end (10b) of the jaw (10), the application of the upper end of each jaw (10) on the shell (100) causing the jaws (10) to close, device characterized in that 'it comprises a locking means (30) connecting the upper ends (10b) of the jaws (10) and comprising two connecting rods (14) and a central segment (13) connecting these connecting rods (14), connecting rods articulated relative to the jaws (10 ) by a first articulation (16) and articulated by a second articulation (61) to the central segment (13), an elastic return means (15) connecting each first articulation (16) at a so-called central point (13b) arranged in the middle of the central segment (13), device comprising at least one movable stop (17) integral with an operating lever (18), stop located above the locking means (30) and able to push the locking means (30) ) down to below an unstable equilibrium position of the locking means (30).connecting rods articulated relative to the jaws (10) by a first articulation (16) and articulated by a second articulation (61) to the central segment (13), an elastic return means (15) connecting each first articulation (16) at a point said central (13b) disposed in the middle of the central segment (13), device comprising at least one movable stop (17) integral with an operating lever (18), stop located above the locking means (30) and suitable pushing the locking means (30) down to below an unstable equilibrium position of the locking means (30).connecting rods articulated relative to the jaws (10) by a first articulation (16) and articulated by a second articulation (61) to the central segment (13), an elastic return means (15) connecting each first articulation (16) at a point said central (13b) disposed in the middle of the central segment (13), device comprising at least one movable stop (17) integral with an operating lever (18), stop located above the locking means (30) and suitable pushing the locking means (30) down to below an unstable equilibrium position of the locking means (30).an elastic return means (15) connecting each first articulation (16) at a so-called central point (13b) disposed in the middle of the central segment (13), device comprising at least one movable stop (17) integral with an operating lever (18), stopper located above the locking means (30) and adapted to push the locking means (30) downwards to below an unstable equilibrium position of the locking means (30) .an elastic return means (15) connecting each first articulation (16) at a so-called central point (13b) disposed in the middle of the central segment (13), device comprising at least one movable stop (17) integral with an operating lever (18), stopper located above the locking means (30) and adapted to push the locking means (30) downwards to below an unstable equilibrium position of the locking means (30) .

2- Gripping device according to claim 1, characterized in that it comprises at least two pairs of coaxial jaws.

3- Device according to one of claims 1 to 2, characterized in that it comprises two stops (17) each comprising a lever (18), each stop (17) being intended to press on one of the connecting rods (14) of the means of locking.

4- Device according to one of claims 1 to 3, characterized in that the frame (2) comprises a sliding support (60) intended to interfere with an upper part of the shell (100) in order to wedge the shell in the device .

5- Device according to one of claims 1 to 4, characterized in that it comprises at least one wedge (32) in its rear part which is intended to bear on a rear face of the base of the shell to position the latter longitudinally relative to the device.

6- Device according to claim 3, characterized in that each lever (18) is integral with two stops (17), each stop (17) being intended to act on a connecting rod (14) associated with a different pair of jaws.