EP0247915A1 - Mechanical device for the alternate motions of a drop hammer or pile driver - Google Patents

Abstract

A housing (1) for the gear train, two shafts (2) and (3) and two gear wheels (4) and (5) form an epicyclic gear train. Added to this is a cable pulley (6) around which several turns of a cable (7) are wound in the opposite sense to the rotation of the motor shaft (2). The cable (7) has a counterweight (8) at one end, and a pile is fixed to the other end. The height of the pile can be adjusted by changing the relative position of the cable (7). <IMAGE>

Description

The subject of the invention is a mechanical device with a planetary gear train, intended to impose on a mass suspended from a cable an alternating movement in a vertical direction comprising a free fall stroke of this mass. This device also allows easy adjustment of the level at which the mass is raised before its free fall travel, in relation to the level where this fall stops and the variations of this last level.

The device of the invention can be used as a pestle to compact material in a pounding box, for example for the preparation of a charge of coking coal, as a hammer forging pestle, as a hammer for driving piles, sheet piling, etc. It will be noted that the variations in the level of mass fall are made in an ascending direction in the case of compaction, because of the volume of material continuously poured into the ramming box, while they are made in descending direction in the other cases, because of the crushing of the parts to be forged or the driving in of the driven piles. The device of the invention is equally suitable in both circumstances.

In known forging hammers and in known threshing sheep or bells, the mass is raised by a winch mechanism which pulls on the cable and releases it to the desired level to allow the free fall stroke of the mass.

In known shelling boxes, the mass is fixed to the lower end of an elongated body provided with friction linings on its two opposite faces; this body is placed between two opposite eccentric wheels. When this body is clamped between the eccentric parts of the wheels it is moved upwards and it falls in free fall with the mass when it is not clamped between the non-eccentric parts of the wheels.

With such a system, there is wear of friction linings, heating and deterioration, due to pressure important and sudden which occurs at the time of the contact of the eccentric, at the beginning of the lifting of the pestle. Eccentrics are relatively complex organs and must be precisely manufactured. The elongated body is a profile which must be chosen in a quality with manufacturing deviations admissible for its use. An imprecision in the profile of the eccentric parts can disturb the operation by causing a delay or an advance of the lifting phase of the pestle.

On the other hand, to allow the shelling box to be emptied of its content, the pestle must be reassembled and held above the box. The operation takes place by the normal rotation of the eccentric wheels which carry out successive lifting phases, alternating with the action of a drumstick brake, acting at the moment of the cessation of the action of the eccentric parts to prevent the drumstick to fall.

The main object of the invention is to provide a device of the kind defined above which does not require manufacturing or mounting precision, with which the risk of premature lifting of the pestle is practically zero and the length of the cable necessary for operation is easily adjustable according to changes in the level of the drop point.

The invention has the additional object of eliminating the need to provide a brake for the ascent of the mass to its highest clearance level, the device being able to function as a winch when desired.

Another object of the invention is to achieve maintenance of the mass at its highest level of clearance by simply stopping the device's engine.

The possible uses of the device of the invention can be classified into two categories: a category like that of pestles to be compacted and forging hammers where the free fall travel of the mass has a low or rather low value of the order of the meter for example (even when it is located between a high level and a low level of mass which are displaced over a large distance as in compaction), and a category like that of threshing sheep where the free fall mass stroke has a significant value of the order of several meters per example.

Consequently, the device of the invention has a first aspect and a second aspect which are respectively suitable for the two categories mentioned above.

In what follows, for ease of explanation, the word pestle will always be used to designate the moving mass even when, in practice, it does not have exactly the appearance of a pestle.

According to the first aspect of the device of the invention for the operation of a pestle, this device comprises a geared motor group, a cable at one end of which is attached a pestle movable in vertical direction, a gear carrier having a frame with two opposite sides provided with bearings, two parallel shafts supported free in rotation by these bearings and each carrying respectively a toothed wheel locked in rotation on said shaft, these toothed wheels meshing together and being located inside said frame; one of the two shafts extends by an end portion outside one of said sides of this frame and it is coupled in rotation with the geared motor unit, however the other of the two shafts extends by an end portion outside on the other of said sides of the frame and this end part is provided with a pulley locked in rotation, the diameter of this pulley being substantially identical shaft and the other toothed wheel having a diameter of markedly greater value the cable coming from the pestle is wound by a few turns around said pulley in a winding direction opposite to the direction of rotation during the operation of the pestle of said toothed wheel of larger diameter, the device further comprising a retractable means of selective immobilization in rotation of the holder gear train.

According to a second aspect of the device of the invention, the pulley on which the cable is wound by a few turns is locked in rotation with the corresponding shaft by means of a centrifugal effect eliminating any coupling between this pulley and this shaft at a value of the rotation of this pulley which corresponds to the free fall of the pestle, however that there is along the cable path below said pulley a guide on which is mounted adjustable in position along said path a proximity detector with which is associated a detectable pad fixed to the cable, this detector controlling when it is influenced by the detectable pad the resting of said retractable means.

• - la figure 1 est une représentation générale simplifée du premier aspect du dispositif de l'invention utilisé dans une installation de pilonnage, le pilon se trouvant dans la position de fin de chute libre,
• - la figure 2 est une vue analogue à la figure 1, le pilon se trouvant au début de sa phase de levage,
• - la figure 3 est une vue analogue à la figure 1, le pilon amorçant sa chute libre,
• - la figure 4 est une vue partille en coupe par l'axe du porte-train d'engrenages faisant partie du dispositif,
• - la figure 5 est une vue générale simplifée du dispositif utilisé comme marteau-pilon de forgeage,
• - la figure 6 est une vue générale simplifée du second aspect du dispositif équipant un véhicule de chantier et utilisé comme mouton de battage pour enfoncer des pilotis de fondation,
• - la figure 7 est une vue agrandie de détail en coupe par l'axe d'une poulie du dispositif munie d'un moyen à effet centrifuge de désaccouplement en rotation,
• - la figure 8 est une vue générale schématique du second aspect du dispositif.

A description will now be given only by way of example of several installations in which a device according to the invention is used according to one and the other of the two aspects of the latter. Reference is made to the accompanying drawings in which:

• FIG. 1 is a simplified general representation of the first aspect of the device of the invention used in a pounding installation, the pestle being in the end of free fall position,
• FIG. 2 is a view similar to FIG. 1, the pestle being at the start of its lifting phase,
• FIG. 3 is a view similar to FIG. 1, the pestle initiating its free fall,
• FIG. 4 is a part view in section through the axis of the gear carrier forming part of the device,
• FIG. 5 is a simplified general view of the device used as a forging hammer,
• FIG. 6 is a simplified general view of the second aspect of the device fitted to a construction vehicle and used as a pile driver for driving foundation piles,
• FIG. 7 is an enlarged detail view in section through the axis of a pulley of the device provided with a centrifugal effect means for uncoupling in rotation,
• - Figure 8 is a schematic general view of the second aspect of the device.

The device shown in Figures 1 to 4 comprises a planetary gear train consisting of a train carrier 1 similar to a rectangular frame, provided in two opposite sides of rolling bearings by which are supported parallel shafts 2 and 3 On the latter are keyed respectively toothed wheels 4 and 5 which mesh together, and which are arranged inside the frame, the wheel 5 being of a diameter much smaller than that of the 4. Therefore the holder train 1 is free to rotate around the shaft 2 which is a motor shaft coupled in rotation with a geared motor group supported at a position outside the train carrier 1. In addition to this epicyclic train, the pulley cable 6, the profile of which is preferably but not necessarily that of a capstan doll and which is keyed mounted to an end part of the shaft 3, outside of the train carrier 1 opposite with respect to the latter of the gear motor group. The minimum winding diameter of this pulley 6 is substantially identical to the pitch diameter of the toothed wheel 5 wedged on the shaft 3. This profile of the pulley 6, well known per se, is used to slide towards the central part of the pulley the cable winding turns 7, when the latter is wound on this pulley, during the rotation of the latter. The whole of the carrier 1 with the gear wheels and the pulley which it carries is advantageously balanced, statically at least, around the shaft 2. The metal cable 7 is wound on the pulley 6, by a number of turns necessary and sufficient, in relation to the profile of this pulley to ensure its adhesion. The direction of winding of the turns of the cable 7 on the pulley 6 is in the opposite direction to the direction of rotation of the motor shaft 2 if it is assumed that the toothed wheels 4 and 5 mesh directly together. At one of the ends of the cable 7 hangs a counterweight 8 after the cable has passed over a deflection pulley 9; at the other end of the cable 7 the pestle hangs after passing the cable over the pulley deflection 10. Preferably a cable tensioning device 11 is mounted near the pulley 10. The counterweight 8 is mounted sliding in a vertical direction in a guide 12. The motor-reduction unit to which the shaft 2 is coupled supports assembly of the train carrier 1 by means of this shaft 2. This geared motor group is itself installed on a fixed platform (not shown), located above the pounding box.

Consider as the start of the operating cycle the situation shown in Figure 1, where the pestle 13 is at the end of free fall. The toothed wheel 4 is driven by the rotation of the shaft 2 of the gear motor, in the direction indicated by the arrow in Figure 1 in a counterclockwise direction when looking at this figure. This results in the opposite direction rotation of the toothed wheel 5 as well as the pulley 6. The latter therefore rotates in the direction that it tends to exert traction, like a capstan, on the strand of the cable 7 to which is attached the pestle 13. But as the train carrier 1 is movable in rotation around the axis 2, the pulley 6 wraps the cable 7 and rotates the train carrier 1 counterclockwise while the toothed wheel 3 rolls on the toothed wheel 4. During this movement, the pulley 6 approaches the pulley 10 and the vertical of the pestle 13. This movement continues until the cable 7 is tensioned under the effect of the weight of the pestle 13 as shown in FIG. 2. At this instant the resistive torque on the pulley 6 is equal to the engine torque on the wheel 5. There is no more rotation of the wheel 5 and of the pulley 6 and the wheel 4 drives with it the carrier 1, counterclockwise. In other words, the carrier 1 is driven upward by the rotation of the wheel 4. This is the lifting phase of the pestle 13. When the gear 5 has passed the point of the gear 4 where the cable 7 is in the diametrical position relative to this toothed wheel 4, it falls downwards, with the undercarriage 1, while rolling on the wheel 4, under the effect the weight of the pestle. This is the free fall phase of the pestle. In fact, the direction of winding of the cable 7 around the pulley 6 allows the wheel 5 to be released relative to the wheel 4, the equality of the resistive torque on the pulley 6 and the motor torque on the wheel 5 being broken, during the passage of the wheel 5 at the top of the wheel 4. The gear motor continuing to rotate, the shelling cycle that has just been described begins again.

To put the pestle at a determined level above the pounding box, at the start of the cycle described above, when the device is in the position of FIG. 1, it suffices to lock the port in rotation in the desired direction -drive 1 around the shaft 2, by operating the drive motor. The pulley 6 then plays its normal role and, by means of the cable 7, it lifts the pestle 13 with a continuous movement to the desired level above the box. In the opposite direction to bring the pestle to a lower level, as the starting position of the working or shelling cycle, it suffices to reverse the rotation of the drive motor during the immobilization of the undercarriage 1; this immobilization can be carried out by any appropriate retractable means, for example by a retractable sliding finger (which will be described later with reference to FIG. 8) mounted on the fixed platform of the gearmotor group and actuated by an electromagnet to come and get on the path of the rotating carrier 1. During the level change (at the start of the cycle) of the pestle 13, the counterweight 8 moves in the opposite direction to that of the pestle. During the use of the pestle the role of the counterweight 8 is to hold the stretched part of the cable 7 which extends between this counterweight and the pulley 6.

The foregoing description relates to the first aspect of the device of the invention in which the height of the free fall of the pestle is relatively low, 0.80 m for example; this value is roughly equivalent to a quarter of the circumference of the gear wheel 4. This situation is also that of the use of the device as a hammer forging, stamping or stamping, illustrated by FIG. 5. On this one the ramming box does not exist and the pestle 13ʹ is a suitable mass guided in its fall between two vertical slides 13ʹA.

When the height of the free fall of the pestle becomes significant (several meters up to 10 m or more), in a threshing bell illustrated in FIG. 6 (on which the means for guiding the mass along its course have been omitted), the device of the invention has a second aspect illustrated by FIGS. 7 and 8.

According to this second aspect the device is as described above except that the pulley 6 (Figure 7) is mounted on the shaft 3 in which is hollowed a key housing 14 more extended in the radial direction and in the axial direction to contain a key 15 movable by sliding in a radial direction on the one hand under the pressure of a compression spring 16, on the other hand under the effect of an oscillating lever 17 which carries a counterweight 18.

The spring 16 is placed between the key 15 and the bottom of the housing 14 and it pushes this key to its rotational coupling position of the shaft 3 and the pulley 6.

The lever 17 is mounted oscillating in the axial extension of the housing 14 about an axis 19, transverse to this housing 14. This lever 17 carries the flyweight 18 at one end and it is articulated by its opposite end, at 20, with the key 15. The arrangement of the lever 17 is such that the counterweight 18 is close to the geometric axis of the shaft 3 when the key 15 is in its coupling position, at a standstill or at a speed of rotation moderate from this tree 3; the counterweight 18 approaches the outer surface of the shaft 3 and the lever 17 pulls the key 15 to its uncoupling position in rotation of the pulley 6 from a determined speed of rotation of the pulley 6 which corresponds to the free fall of the pestle.

Of course, other centrifugal means capable of eliminating at a given speed the rotational coupling of the shaft 3 and the pulley 6 can be used if desired, the solution described here is only an example.

FIG. 8 schematically shows that the second aspect of the invention comprises a retractable sliding finger 21 actuated by an electromagnet 22 or another equivalent control means. This assembly can be mounted on the platform of the gearmotor group or fixed directly to the boom of the construction vehicle (Figure 6). In all cases the retractable finger 21 has a rest position at which it does not hinder the rotation of the train carrier 1 and a service position at which it is located on the path of the train carrier 1 and immobilizes it in rotation in the direction which corresponds to the rise of the toothed wheel 5 on the toothed wheel 4, by meshing and rolling of the first on the second as explained above for the transition from the position of Figure 2 to that of Figure 3 In this state of the device, the cable 7 is pulled continuously by the pulley 6 itself driven by the shaft 3 and the toothed wheel 5; the speed of rotation is then such that the key 15 remains in its coupling position under the effect of the spring 16.

The finger 21 which has just been described can be confused with that which serves to immobilize the train carrier 1 when it is desired to raise the level at which the pestle 13 must be pulled before its free fall; another similar finger can be used to immobilize the train carrier 1 in rotation in opposite direction when it is desired to lower this same level;

FIG. 8 also shows that the cable 7 is provided with a pad 23 which can be detected from a distance and that a guide 24 is fixed by means not shown to extend parallel to the path traveled by the cable 7. On this guide 24 is mounted a proximity detector 25 adjustable in position along this guide 24. This detector controls the position changes of the retractable finger 21 during the operation of the device, as will now be explained.

When the pestle 13ʺ (figure 6) must be raised to a level located at a great height above the level at the bottom of the free fall travel, the carrier 1 completes its rotational movement as described above between its position visible in FIG. 1 and its position visible in FIG. 3.

The finger 21 is normally always in its service position on the passage of the train carrier 1. When the latter reaches its position of FIG. 2 it is stopped by the finger 21 so that the pulley 6 acts like a capstan and continues to mount the cable 7 and the pestle 13ʹ. The detectable pad 23 and the proximity detector 25 have been previously adjusted in position so that the pad 23 influences the detector 25 when the pestle 13ʺ _____ is close to its high level. The detector 25 controls the withdrawal of the finger 21 which moves back to its rest position and releases the carrier 1. The latter resumes its rotation from the position of FIG. 2 to that of FIG. 3. During this movement the pestle 13ʺ is incurs raised; it reaches its high level when the train carrier 1 reaches its position of FIG. 3 where the cable 7 is in diametrical position relative to the toothed wheel 2. Immediately after the start of the rotation of the train carrier 1, the detectable stud 23 moves away from the detector 25 and the finger 21 returns to its service position.

As soon as the carrier 1 has crossed its position in FIG. 3, it begins to rotate faster around the shaft 2, accompanying the pestle 13ʺ in its fall. The toothed wheel 5 rolls on the toothed wheel 4 and rotates the pulley 6 more and more quickly so that the counterweight 18 subjected to the centrifugal force, actuates the key 15 and uncouples the shaft 3 of this pulley 6. it rotates freely, allowing the cable 7 to unwind until the pestle 13 "falls off at its low level. At this time, the cable 7 no longer unwinds; the counterweight 18 is no longer subjected to the centrifugal force and the spring 16 pushes the key 15 and re-establishes the coupling between the pulley 6 and the shaft 3.

Under the effect of the gearmotor the train carrier 1, which had assumed a substantially vertical position during the free rotation of the pulley 6, is again driven in rotation, by the engagement of the toothed wheel 4 and the toothed wheel 5 which drives the pulley 6, towards its position in FIG. 2 where it is stopped by finger 21 and the cycle is repeated.

The invention is not limited to the embodiment described, but on the contrary covers all the variants which could be made to it without departing from its scope or its spirit.

Claims (7)

1. Mechanical device for operating a pestle, comprising a geared motor group, a cable (7) at one end of which is attached a pestle (13) movable in vertical direction, characterized in that it comprises a holder gear train (1) having a frame with two opposite sides provided with bearings, two parallel shafts (2,3) supported freely in rotation by these bearings and each carrying respectively a toothed wheel (4,5) wedged in rotation on said shaft, these toothed wheels meshing together and being located inside said frame; one of the two shafts (2) extending by an end portion outside one of said sides of this frame and being coupled in rotation with the geared motor group, while the other of the two shafts (3) extends by an end part outside the other of said sides of the frame and this end part is provided with a pulley (6) locked in rotation, the diameter of this pulley (6) being substantially identical to the pitch diameter of the toothed wheel (5 ) mounted on the same shaft (3) and the other toothed wheel (4) having a significantly larger value diameter; the cable (7) coming from the pestle (13) being wound by a few turns around said pulley (6) in a winding direction opposite to the direction of rotation during the operation of the pestle (13) of said toothed wheel (4) of larger diameter, the device further comprising a retractable means of selective immobilization in rotation of the gear carrier (1). 2. Device according to claim 1 characterized in that the pulley (6) around which wind several turns of the cable (7) is a pulley of the type of a capstan doll whose minimum diameter is substantially identical to the pitch diameter of the toothed wheel (5). 3. Device according to claim 1 characterized in that the whole of the train carrier (1) with the wheels toothed (4,5) and the pulley (6) which it carries is balanced, statically at least, around the shaft (2) coupled to the geared motor group. 4. Device according to claim 1 characterized in that after leaving the pulley (6) from the pestle (13) the cable (7) passes over a deflection pulley (9) and it is fixed at its end to a counterweight (8) free in vertical direction which holds this cable in the stretched state. 5. Device according to claim 1 characterized in that the pulley (6) on which the cable (7) is wound by a few turns is locked in rotation with the shaft (3) corresponding by means of an effect means centrifugal eliminating any coupling between this pulley (6) and this shaft (3) to a value of the rotation of this pulley (6) which corresponds to the free fall of the pestle, however that it exists along the path of the cable (7 ) below said pulley (6) a guide (19) on which is mounted adjustable in position along said path a proximity detector (25) with which is associated a detectable stud (23) fixed to the cable (7), detector (25) controlling when it is influenced by the detectable stud (23) the resting of said retractable means (24). 6. Device according to claim 5 characterized in that the shaft (3) is provided, internally to the pulley (6) with a key housing (14) extending in radial and axial direction in which is slidably mounted radially a key (15), the latter being pushed into its coupling position by a spring (16) mounted in said housing and being connected by an oscillating lever (17) to a release weight (18) mounted in said housing. 7. Device according to any one of claims 1, 5 characterized in that the retractable means of selective immobilization in rotation of the gear carrier (1) comprises a movable finger (21) operable by an electromagnet ( 22) and having a service position at which it is located on the passage of the train carrier (1) rotating around the axis (2) and a rest position at which it leaves this same train carrier free to rotate ( 1) during the upward movement of the pestle (13ʺ).

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