WO2018172589A2

WO2018172589A2 - Automatic device for driving stakes

Info

Publication number: WO2018172589A2
Application number: PCT/ES2018/070222
Authority: WO
Inventors: Jordi Vallès Salvadó
Original assignee: Valles Salvado Jordi
Priority date: 2017-03-22
Filing date: 2018-03-22
Publication date: 2018-09-27
Also published as: WO2018172589A3; ES1180414Y; ES1180414U

Abstract

The present invention relates to an automatic device (1) for driving stakes (100), comprising: a housing (22), a receiving socket (2) forming a receiving cavity (4) for receiving the first striking end (102) of a stake (100), automatic driving means (8), impact means (10), and a longitudinal guide (12) for guiding the impact means (10). The impact means (10) are movable along the guide, driven in an alternating manner by said driving means (8) between [i] a first position remote from the receiving socket (2), and [ii] a second position in which the impact means (10) deliver a driving impulse on the stake (100). Furthermore, the receiving socket (2) is mounted on a seat (34) of the housing (22) by means of fitting comprising press fitting and shrink fitting. The receiving socket (2) also forms at least part of the guide (12).

Description

AUTOMATIC DEVICE FOR NAILING STAKES DESCRIPTION

Field of the Invention

The invention relates to an automatic device for nailing stakes comprising: a housing, a receiving bushing that forms a receiving cavity for receiving, through an insertion end, the first striking end of a stake to be nailed into the ground, automatic actuation means, impact means and a longitudinal guide to guide said impact means.

State of the art

Automatic staking devices are known as those described in the previous paragraph. The known devices have an externally mounted receiving sleeve and adjacent to a main housing, into which the stake to be nailed is inserted. In addition, these devices incorporate drive means, such as a gasoline or pneumatic engine, that drive impact means that strike the stake. These means are formed by a heavy sliding element in a guide in the housing, which hits on the striking end of the stake. The striking end is the opposite end to the nailing end, which is the end that is driven into the ground. Thanks to the drive means, the user does not have to move the weight with the force of his own body to hit the stake, but the beating is automatic. This type of device performs between 800 and 1500 strokes per minute on the stake. To reduce the vibrations that the user receives caused by the beating, the device has dampened handles. However, despite the cushioning of the handles, the rest of the device is affected by this hit. In particular, the bushing is highly requested to fatigue and it is often broken by the point closest to the area adjacent to the housing where the stake hits. Summary of the invention

The purpose of the invention is to provide an automatic device for nailing stakes of the type indicated at the beginning, which prevents premature ruptures in the device and especially that prolongs the life of the receiving cap.

This purpose is achieved by an automatic device for nailing stakes of the type indicated at the beginning, characterized in that said impact means are movable along said guide, actuated alternatively by said actuation means between a first position away from said reception bushing and a second position in which said impact means impart a driving pulse on said first end of said stake, because said receiving bushing is mounted on a seat of said housing by means of an adjustment of the group comprising the pressure adjustments and hot pressure adjustments and why said receiving cap forms at least a part of said guide intended to guide said impact means.

Indeed, the sleeve according to the invention has continuity inside the housing and sits firmly inside the seat of the housing. This has a multiplier effect of the fatigue resistance of the assembly, because the impact means strike in an area where the bushing has continuity and the bending stresses on the bushing are better absorbed. At the moment of the impact on the stake, the set of impact means, bushing and housing, in the striking zone, form a very reinforced structural unit that allows the tensions caused by the percussions to be distributed in a much more distributed way. Consequently, the resistance of the bushing and of the device in general improves markedly with respect to those of the prior art. Furthermore, the invention encompasses a series of preferred features that are the subject of the dependent claims and whose usefulness will be highlighted later in the detailed description of an embodiment of the invention.

Preferably, said impact means comprise a hammer and an anvil, said hammer being actuated by said actuating means against said anvil so that said anvil impacts on said first end of said stake. In this case, the hammer is a lightweight element that can be easily moved alternately, while the anvil is a heavier and stiffer element. This allows the anvil to have a diameter that covers the entire striking area, better distributing the efforts and prolonging its useful life. In this way, the pressure exerted by said impact means is exerted on the entire surface of the first end of the stake and also prevents the hammer from being in direct contact with said stake and, therefore, damaging it. . Preferably, said hammer or said anvil comprise centering axis and said device, further comprising a damping ring that is mounted on said centering axis, guided in said longitudinal guide to dampen lateral movements of said impact means when said hammer and said anvil impart said impulse. Preventing lateral movements caused by percussion from being transmitted to the rest of the device, it also prolongs the life of the receiving cap.

In one embodiment, said damping ring comprises a first and a second metal half-shells separated by an elastic ring, which reduces wear on the device guide.

Preferably, in the device according to the invention, at least one of said anvil and said hammer are hollow inside, which reduces the inertia of the moving elements and allows to increase the striking speed.

In another embodiment, it is intended to avoid jams in the actuation means said anvil comprises a first perimeter groove close to the area in which said anvil hits on said stake and in said first groove it is mounted a first scraper ring of trapezoidal section protruding from the perimeter of said anvil, positioned such that the major base of said trapezoidal section is on the side of said cavity. Thanks to this trapezoidal shape, the scraper ring prevents splinters or metallic pieces of the stake from entering the guide area and consequently can damage the guided components or the guide itself. Especially preferably, the section of said ring is a right trapezoid.

In another preferred embodiment, said scraper ring comprises a first outer part made of a rigid polymer and an inner part as a rubber o-ring. The rigid polymer can be, for example, a polyamide (PA) with fiberglass charge, an acrylonitrile butadiene styrene (ABS) or other wear-resistant plastics. The O-ring provides elasticity to the scraper ring to ensure a good scratch of the surface, while the outer part of rigid polymer prevents splinters or other loose pieces of material from penetrating. Particularly preferably, said anvil comprises a second perimeter groove adjacent to said first perimeter groove and a guide ring made of a rigid polymer is mounted on said second groove. This guide ring is preferably square or rectangular in order to ensure good support on the walls of the guide. The combination with the scraper ring provides very efficient guidance results.

In another embodiment, the anvil comprises a third perimeter groove adjacent to said second perimeter groove and in said third groove a rubber o-ring is mounted which provides a good seal inside the cylinder and prevents the massive outflow of lubrication oil. In another embodiment said actuation means comprise a piston that pneumatically displaces said hammer against said anvil alternatively between said first and said second position, and said piston comprises a fourth perimeter groove close to the area in which said piston drives pneumatically said hammer and in said fourth slot a second scraper ring of trapezoidal section protruding from the perimeter of said piston, positioned such that the major base of said trapezoidal section is on the side of said hammer.

In a particularly preferred embodiment, said hammer comprises a fifth perimeter groove near the end of said hammer away from said anvil and in said fifth groove a second guiding ring comprising an inner rubber o-ring and an outer part of rigid polymer

Particularly preferably, the device according to the invention also comprises a reduction bushing mounted inside said receiving bushing to reduce the cross section of said receiving cavity in such a way that it adapts to the outer contour of said stake and in the position mounted, it extends inside said reception bushing to a position in which, in said second position, said impact means do not impact on said reduction bushing and fastening means for securing said reduction bushing in said mounted position . Thanks to the reduction bushing, the receiving bushing adapts perfectly to the contour of the stake to be nailed. Therefore, the stresses received by the bushing during the striking are centered, so that no unwanted bending stresses are introduced into the receiving bushing. It should be noted that in the invention, the concept of adapting to the outer contour of the stake does not necessarily mean that the reduction bushing has a cross-section that is the negative shape of the stake's contour. Simply, the reduction bushing provides the necessary support, through at least three points that form a support triangle of the stake contour to prevent the stake from moving freely. For example, if the stake is rectangular in cross-section, the reduction sleeve may have a circular cross-section. However, the four edges of the cross section of the stake are sufficiently guided inside the reduction bushing to prevent the introduction of bending stresses of the stake in the receiving bushing.

Especially preferably, the device comprises a housing and said receiving bushing forms at least the part of said guide intended to guide said anvil and said receiving bushing is mounted on said housing by means of a pressure adjustment or a pressure adjustment in hot. On the one hand, the tightness of the assembly, since the anvil makes its entire journey through the part of the bush mounted on the housing. On the other hand, the percussion efforts caused by the striking of the anvil pass from the bushing to the housing and are more efficiently damped. Preferably, said fastening means comprise at least one elastically preloaded pin that is transversely connected to said receiving sleeve. This type of joint is easy to machine and assemble and disassemble. This type of joint is advisable for small stake applications.

In another embodiment said fastening means comprise a fastening bushing, and said fastening bushing and said receiving bushing comprise thread means for mutual mounting between the two. This type of union allows the union between pieces of different materials and resists well the efforts produced by the device. In addition, this type of joint is standard and interchangeable.

Alternatively, said fastening means comprise a fastening bushing, and by which said fastening bushing and said receiving bushing comprise bayonet means for mutual mounting between the two. Thanks to this type of joint, the operator can easily assemble and disassemble the joint, gaining working speed when there are many different types of stakes that must be nailed.

Likewise, the invention also encompasses other detail features illustrated in the detailed description of an embodiment of the invention and in the accompanying figures.

Brief description of the drawings

Other advantages and features of the invention can be seen from the following description, in which, without any limitation, preferred embodiments of the invention are mentioned, mentioning the accompanying drawings. The figures show:

Fig. 1, an explanatory side view of the principle of operation of the automatic staking device according to the invention. Fig. 2, a front, bottom perspective view of a first embodiment of a device according to the invention, without the motor.

Fig. 3, a rear, top perspective view of a first embodiment of a device according to the invention, without the engine. Fig. 4, a longitudinal section of the device of figures 2 and 3 along a central plane thereof, but with a reduction bushing mounted on the receiving bushing.

Fig. 4A, an enlarged detail of zone A of Figure 4.

Fig. 4B, an enlarged detail of zone B of Figure 4.

Fig. 5A, a partial detail, longitudinally cut, of a second embodiment of a device according to the invention in a first remote position.

Fig. 5B, a partial detail, longitudinally cut, of a second embodiment of a device according to the invention in a second impact position.

Fig. 6, a partial detail, longitudinally cut, of a third embodiment of a device according to the invention, in particular of the area of the receiving sleeve.

Fig. 7, a perspective view of the clamping sleeve of Figure 6.

Fig. 8, a partial detail, longitudinally cut, of a fourth embodiment of a device according to the invention, in particular of the area of the receiving sleeve. Detailed description of embodiments of the invention

A generic automatic device 1 for nailing stakes 100 according to the invention is shown in Figure 1. In the context of the invention, a stake 100 can be a wooden stick with a pointed end, but it can also be a pointed metal post, large nails or other similar longitudinal elements, intended for mounting fences, or structures for Hang vegetables such as grapevines, vegetables or others. On the other hand, the cross section of the stake 100 should not be construed as limiting. The cross section is usually circular or square in the case of wooden stakes. However, in the case of metal posts, the shapes can be circular, quadrangular tubes, U-profiles, L-shaped or others. In addition, a device 1 with automatic actuation refers to the fact that the operator 108 using the device must not perform the main part of the stabbing force of the stake. On the contrary, this force comes from the interaction between an engine, and a weight that is driven by the engine to carry out the main hitting effort on the stake. However, the operator must hold the device and accompany it in its downward nailing movement. Eventually, the operator 108 may slightly push the device downward when the ground on which the stake is driven is especially hard.

A first embodiment of the automatic staking device 1 according to the invention is shown in Figures 2 to 4. The device 1 comprising a housing 22 in which a receiving bushing 2 is formed which forms the receiving cavity 4 to receive through the insertion end 6, the first striking end 102 of the stake 100 to be nailed into the ground 104.

The device 1 also has automatic actuation means 8 which can be, for example, an electric, gasoline, pneumatic or similar engine. However, taking into account that a device 1 for driving stakes of this type is usually used in a rural environment, it is preferred that the engine be gasoline. This provides greater power autonomy to device 1. In figures 2 and 3 the motor is not represented, while in figure 4, it is represented by a dashed rectangle. The engine drives a main shaft 84 provided with a pinion 86 that meshes with a crown 88 that rotates the shaft of the crankshaft 90 that is mechanically attached to the connecting rod 92 of the piston 68.

Thanks to this mechanism, the piston 68 moves in an alternative upward, downward movement that causes a pneumatic effect thanks to the ports provided in the cylinder. In addition, the device 1 also comprises an impact means 10, formed by a hammer 18 and an anvil 20 and a longitudinal guide 12 for guiding the impact means 10. Especially preferably, both the hammer 18, and the anvil 20, They are made of carbon steel, totally or partially tempered. The impact means 10 are movable along the guide 12, alternatively actuated by said actuation means 8 between a first position away from said receiving bushing 2 and a second position in which said impact means 10 they impart a nailing pulse on the first end 102 of said stake 100. In Figures 4 and 4B it can be seen that the receiving bushing 2 is mounted in a seat 34 of the housing 22 by means of a pressure adjustment which significantly reinforces this area of the device that is where the percussions occur. Particularly preferably, the mounting of the receiving bushing 2 is carried out under hot pressure. Another element that solves the technical problem of preventing premature breakage in the device and especially that prolongs the life of the receiving bushing consists in that said receiving bushing 2 forms at least a part of said guide 12 intended to guide said means. of impact 10. Particularly preferably, said receiving bushing 2 forms the part of the guide 12 on which the entire anvil 20 travels. Thus, at the point where impacts occur the receiving bushing assembly 2, anvil 20 and housing 22 form a very robust area to correctly absorb the percussions that occur.

In the figures, it can be seen how the hammer 18 is actuated by the actuation means 8 against said anvil 20 so that the anvil 20 impacts on the first end 102 of the stake 100.

In the device 1 of Figures 2 to 4B, the hammer 18 also forms a centering axis 38. On the centered axis 38 the inside diameter of a damping ring 40 is mounted which is externally guided in the longitudinal guide 12 to dampen the lateral movements of hammer 18 and anvil 20 when they impart momentum. It is especially preferred that the damping ring 40 It comprises a first and a second metal half shells 78, 80 separated by an elastic ring 82. In addition, another elastic ring 94 may be provided by the upper part of the shock absorber 40 which dampens the rebound of the shock ring against the housing 22 during percussions. In Figure 4A it can be seen that the anvil 20 comprises a first perimeter groove 50 close to the area where the anvil 20 hits the stake 100. In this area, chips or pieces of the stake 100 can be detached. Therefore, to to prevent these pieces from entering inside the guide 12 and causing the device 1 to grind, a first scraper ring 52 of trapezoidal section is mounted in the first groove 50 that protrudes from the perimeter of said anvil 20, positioned so that the Major base 54 of said trapezoidal section is on the side of the cavity 4. Particularly preferably, the section of the scraper ring 52 is a trapezoid, with two parallel sides.

On the other hand, as seen in Figure 4A, the scraper ring 52 is formed by two parts. A first outer part 56 is made from a rigid polymer, such as polyamide 6, polyamide 66 or ABS and the inner part 58 is configured as a rubber O-ring of the rubber type. The outer part 56 guarantees reduced wear, while the inner part provides elasticity so that the scraper ring 52 is better suited to the surface of the guide 12. It should be noted that the O-ring does not exclude other sections other than the circular. For example, it could be a square joint, like those mounted on other parts of device 1.

The anvil 20 has a second perimeter groove 60 adjacent to the first perimeter groove 50 and there is mounted a guide ring 62 made of a rigid polymer. In addition, the anvil 20 has a third perimeter groove 64 adjacent to the second perimeter groove 60 and in which a rubber O-ring 66 is mounted that prevents lubricating oil from leaving the inside of the cylinder.

On the other hand, in the device 1 of FIGS. 2 to 4B, the drive means 8 in addition to the engine and the gear transmission, comprise a piston 68 that pneumatically displaces the hammer 18 against said anvil 20 in an alternative way between the first position away from the receiving bushing 2 and the second position in which the anvil 20 hits the stake 100 driven by the hammer 18. This piston 68 comprises a fourth perimeter groove 70 close to the area in which the piston 68 pneumatically actuated said hammer 18. In this fourth groove 70 a second scraper ring 72 of trapezoidal section is mounted protruding from the perimeter of said piston 68, positioned such that the major base of said trapezoidal section is on the side of said hammer 18.

Finally, the figures show that the hammer 18 comprises a fifth perimeter groove 74 near the end of the hammer 18 away from the anvil 20. A second guide ring 76 is mounted on the fifth groove 74 which comprises an inner rubber o-ring and an outer part of rigid polymer.

Next, a second embodiment of the device 1 according to the invention is described on the basis of Figures 5A to 5B.

The second embodiment of the device 1 of Figures 5A and 5B has a housing 22 on which the automatic actuating means 8 are mounted.

Preferably, the housing 22 is made of a light alloy, such as aluminum alloy.

The device 1 further comprises a receiving sleeve 2 as a hollow cylindrical body mounted in the housing 22, an impact means 10 and a longitudinal guide 12 for guiding the impact means 10.

A pair of handles 44 are disposed in the housing 22 through which, the operator 108 can manipulate the device 1 during use or transport. Preferably, the handles 44 extend in one direction, parallel to the direction of the receiving bushing 2 of the stake. In addition, the handles 44 have damping means, such as a spring in each handle 44 that disengages them from the oscillating movement of the shaft 36 on which they are mounted and therefore from the rest of the device 1. This prevents the operator 108 from receiving the most harmful part of the vibrations of the device 1. Alternatively, the handles 44 of the devices 1 according to the invention may be oriented transversely to the direction of the receiving sleeve 2.

Timely, the handles 44 have an engine activation and shutdown system to improve the safety of use. This system, not shown in detail in the invention consists of a double button, diametrically opposite on the handle 44. The first activation button is operated with the palm of the hand and allows activating the second engine acceleration button. Thus, if the operator 108 does not simultaneously activate both buttons, the device 1 stops automatically. In this embodiment, the impact means 10 are again a hammer 18 and an anvil 20. Both the hammer 18 and the anvil 20 are guided laterally by o-rings of preferably circular section. The hammer 18 is driven by a pneumatic effect provided by the engine air thrust into the cylinder sleeve 42. This jacket 42 acts as a longitudinal guide 12 for the hammer 18, by means of a set of ports not shown in detail. For this, the motor is coupled to a connecting rod and piston system, not shown, responsible for generating the pressure on the hammer 18, which is the one that moves alternately. This pneumatic drive principle is widely known to the person skilled in the art. Cylinder 42 is preferably cylindrical in cross-section, but not essential for the invention. Preferably, the anvil 20 is a hollow cylinder internally, and closed by the striking surface, which allows to reduce weight and gain speed of hammer driving 18. Later, the operation of hammer 18 and anvil 20 for driving will be explained in detail. the stake 100. Especially preferably, both the hammer 18, and the anvil 20, are made of carbon steel, totally or partially tempered.

Also preferably, the anvil 20 comprises upper centering axis 38 configured to receive the impacts of said hammer 18 and the device 1, further comprising a damping ring 40 which is mounted on said centering axis 38, guided in the longitudinal guide 12 for damping the lateral movements of said anvil 20 when I receive the impacts of said hammer 18. From the bottom of the housing 22, the hollow receiving sleeve 2 protrudes, forming a receiving cavity 4 to receive the stake 100. Through the insertion end 6 of the receiving sleeve 2, that is, the far end of the housing 22, the device 1 receives the first end 102 of the stake 100. The receiving bushing 2 is preferably cylindrical. However, it could have other cross sections.

The receiving bushing 2 is made of a hard material, such as a chrome alloy carbon steel.

The hammer 18 and the anvil 20 are movable along the guide 12, alternately actuated by the actuating means 8 between a first position away from the receiving sleeve 2 (see figure 5A) and a second position in the that the impact means 10, that is to say the hammer 18 first, and then the anvil 20, impart a driving impulse on the first end 102 of the stake 100 (see Figure 5B). Upon receiving the impact of the hammer 18, the anvil 20 descends to strike on the first end 102 of the stake 100. The second end 106 of the stake has a tip intended to facilitate the penetration of the stake 100 into the ground 104.

In order to reinforce the receiving bushing 2 and prolonging its useful life, a reduction bushing 14 is provided in the invention, mounted inside the receiving bushing 2 to reduce the cross-section of the receiving cavity 4. In this way, the cavity 4 adapts to at least three points of the cross section of the stake and provide a lateral centering of the stake. The connection between the reduction sleeve 14 and the stake 100 is a connection with a slight play. This allows the inner shape of the reduction bushing 14 to adapt to the outer contour of the stake 100, which prevents the stake 100 from moving freely within the receiving bushing 2.

Furthermore, in a further improvement of the invention, it is provided that in the mounted position, the reduction bushing 14 extends inside the receiving bushing 2, but only, to a position in which, in the second operating position of the device 1, that is to say at the moment that the anvil 20 hits the stake 100, the impact means 10 never impact on the bushing reduction 14. This improvement is especially relevant, since the reduction sleeve 14 does not receive the most important part of the impacts of the anvil 20.

Finally, the device 1 also comprises fastening means 16 for holding the reduction bushing 14 in the assembled position. Thanks to the fact that the reduction sleeve 14 receives no impacts from the anvil 20, it is avoided unnecessarily damaging the fastening means 16 by the longitudinal stresses derived from the striking of the stake 100.

In this second embodiment, in order to avoid retaining the retaining bushing 24 in its assembled position, the latter and the receiving bushing 2 comprise thread means 26 for mutual mounting between them. Additionally, and to prevent the holding bushing 24 from being loosened due to the vibrations of the striking, the device 1 comprises an elastically preloaded pin 28 that transversely connects the receiving bushing 2 with the holding bushing 24. Especially preferably, The device 1 according to the invention incorporates a set of several reduction bushings 14, to give greater versatility to the device 1.

Both the reduction bushing 14, and its arrangement inside the receiving bushing 2, as well as the securing means 16 for holding both attached bushes are also contemplated to be mounted on the device 1 described above.

To mount the reduction bushing 14, it is sufficient to insert it into the receiving bushing, and then screw the fastening bushing 24 over the thread of the receiving bushing 2. Finally, the pin 28 is inserted into the corresponding hole of the receiving bushing 2 to prevent the reduction bushing from loosening during the nailing procedure.

Also to obtain an optimal fixation, the reduction bushing 14 has an annular flange 46 projecting radially. In turn, the clamping sleeve 24 has an annular flange 48 that penetrates radially. In this way, the reduction bushing 14 is perfectly retained in the longitudinal direction of the receiving bushing 2 since the annular flange 46 is caught between the leading edge of the receiving bushing 2 and the annular shoulder 48 of the holding bushing 24. Particularly preferably, in this embodiment and with the aim of further increasing the durability of the receiving bushing 2, the receiving bushing 2 itself forms part of the longitudinal guide 12. In this embodiment, the receiving bushing 2 forms part of the guide 12 intended to guide the entire anvil 20, while the hammer 18 is guided in an independent sleeve 42. This also improves the tightness of the device 1 in the hammer area 18.

As in the previous embodiment, the receiving bushing 2 is mounted in the housing 22 by means of a pressure adjustment or a hot pressure adjustment. Furthermore, in order to have an optimal assembly, on its upper part, the receiving bushing 2 has an annular flange 32 protruding from the main body of the receiving bushing 2. This annular flange 32 rests on an annular seat 34 provided in the housing 22 .

Other embodiments of the automatic staking device according to the invention that share a large part of the characteristics described in the preceding paragraphs are shown below. Therefore, from now on only the differentiating elements will be described, while for the common elements reference is made to the description of the first and second embodiments.

In the embodiment of Figures 6 and 7, the fastening means 16 comprise a fastening bush 24 similar to that of the previous embodiment. However, in this case the holding bushing 24 and the receiving bushing 2 comprise bayonet means 30 for mutual mounting between the two to facilitate the rapid assembly and disassembly of the reduction bushing 14. The bayonet means are formed by three L-grooves that start at the insertion mouth of the securing bushing 24. Correspondingly, the receiving bushing 2 incorporates three distributed bolts, preferably 120 ^s around the perimeter of the bushing 12 and which fit into said grooves.

This embodiment also incorporates an elastically preloaded pin 28 that transversely connects the receiving bushing 2 with the holding bushing 24. Finally, the embodiment according to FIG. 8, the device 1 incorporates two elastically preloaded pins 28 that transversely connect the receiving bushing 2 with the reducing bushing 14.

All the fastening means 16 described herein could be mounted in the embodiments described above, with a suitable receiving sleeve.

To use the device 1 according to the invention especially ergonomically by a single user, it is preferred that the operator place the stake on the ground, resting on an object that slightly raises the first striking end 102. In this position, the operator 108 inserts the first end 102 into the receiving bushing 2 or, if necessary, into the reducing bushing 14 until it stops. Then lift the device 1 to put the set formed by stake 100 and device 1 in the nailing direction. The nailing direction does not have to be vertical. Finally, the activation button and the engine acceleration button are actuated and the device 1 is simply held as in figure 1 and is accompanied during nailing.

The embodiments described so far represent non-limiting examples, so that the person skilled in the art will understand that beyond the examples shown, multiple combinations between the claimed characteristics are possible within the scope of the invention.

Claims

1 .- Automatic device (1) to drive stakes (100) comprising:

[a] a housing (22),

[b] a receiving bushing (2) forming a receiving cavity (4) to receive, through an insertion end (6), the first striking end (102) of a stake (100) to be nailed on the ground (104),

[c] automatic drive means (8),

[d] means of impact (10) and

[e] a longitudinal guide (12) for guiding said impact means (10), characterized in that

[f] said impact means (10) are movable along said guide (12), alternatively actuated by said actuation means (8) between

[i] a first position away from said receiving socket (2) and

[ii] a second position in which said impact means (10) impart a nailing pulse on said first end (102) of said stake (100), because

[g] said receiving bushing (2) is mounted on a seat (34) of said housing (22) by means of an adjustment of the group comprising the pressure adjustments and the hot pressure adjustments and why

[h] said receiving cap (2) forms, at least, a part of said guide (12) intended to guide said impact means (10).

2. Device according to claim 1, characterized in that said impact means (10) comprise a hammer (18) and an anvil (20), said hammer (18) being actuated by said actuating means (8) against said anvil (20) for said anvil (20) to impact said first end (102) of said stake (100).

3. Device according to claim 2, characterized in that said hammer (18) or said anvil (20) comprises centering axis (38) and that said device (1) also comprises a damping ring (40) which is mounted on said axis centering (38), guided in said longitudinal guide (12) to dampen the lateral movements of said impact means (10) when said hammer (18) and said anvil (20) impart said impulse.

4. - Device according to claim 3, characterized in that said damping ring (40) comprises a first and second metal half shells (78, 80) separated by an elastic ring (82).

5. - Device (1) according to any of claims 2 to 4, characterized in that said anvil (20) comprises a first perimeter groove (50) close to the area in which said anvil (20) hits on said stake (100 ) and because in said first groove (50) a first scraper ring (52) of trapezoidal section is mounted protruding from the perimeter of said anvil (20), positioned such that the major base (54) of said trapezoidal section is of the side of said cavity (4).

6. - Device (1) according to claim 5, characterized in that said scraper ring (52) comprises a first outer part (56) made of a rigid polymer and an inner part (58) as a rubber o-ring.

7. - Device (1) according to claim 5 or 6, characterized in that said anvil (20) comprises a second perimeter groove (60) adjacent to said first perimeter groove (50) and that in said second groove (60) is mounted a guide ring (62) made of a rigid polymer.

8. Device (1) according to any of claims 5 to 7, characterized in that said anvil (20) comprises a third perimeter groove (64) adjacent to said second perimeter groove (60) and why in said third groove (64 ) a rubber O-ring (66) is mounted.

9. Device (1) according to any of claims 2 to 8, characterized in that said actuating means (8) comprise a piston (68) that pneumatically displaces said hammer (18) against said anvil (20) alternately between said first and said second position, and by which said piston (68) comprises a fourth perimeter groove (70) close to the area in which said piston (68) pneumatically actuates said hammer (18) and by which in said fourth groove ( 70) is mounted a second scraper ring (72) of trapezoidal section protruding from the perimeter of said piston (68), positioned such that the major base of said trapezoidal section is on the side of said hammer (18).

10. - Device (1) according to any of claims 2 to 9, characterized in that said hammer (18) comprises a fifth perimeter groove (74) close to the end of said hammer (18) away from said anvil (20) and by that in said fifth groove (74) a second guide ring (76) comprising an inner rubber o-ring and an outer part of rigid polymer is mounted.

eleven . - Device according to any of claims 1 to 10, characterized in that it further comprises

[a] a reduction bushing (14) mounted inside said receiving bushing (2) to reduce the cross section of said receiving cavity (4) in such a way that it adapts to the outer contour of said stake (100) and that in the mounted position, it extends inside said receiving bushing (2) to a position in which, in said second position, said impact means (10) do not impact on said reduction bushing (14) and

[b] fastening means (16) for holding said reduction bushing (14) in said mounted position.

12. Device according to claim 1, characterized in that said fastening means (16) comprise at least one elastically preloaded pin (28) which is connected transversely to said receiving socket (2).

13. - Device according to claim 12, characterized in that said fastening means (16) comprise a fastening bushing (24), and in which said fastening bushing (24) and said receiving bushing (2) comprise thread means (26) for mutual mounting between the two.

14. - Device according to claim 12, characterized in that said fastening means (16) comprise a fastening bushing (24), and by which said bushing of fastener (24) and said receiving bushing (2) comprise bayonet means (30) for mutual mounting between them.