CN201009226Y

CN201009226Y - Electric hammer

Info

Publication number: CN201009226Y
Application number: CNU2006201307499U
Authority: CN
Inventors: 强尼·鲍瑞那图
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2006-07-28
Filing date: 2006-07-28
Publication date: 2008-01-23
Anticipated expiration: 2016-07-28

Abstract

A hammer comprises a housing (2), an intermediate shaft (26) rotationally arranged on the housing (2), a motor (24) to rotate the intermediate shaft (26), an aiguille (4), a first impacting block (16), a second impacting block (20), a first impacting groupware (36; 40,46,50,54) for the first impacting block (16) hammering the tool (4) along the lengthways axial line and a second hammering groupware (36; 40,46,50,54) for the second impacting block (20) hammering the tool (4) along the lengthways axial line. The hammering of the second hammering groupware (36; 40, 46, 50, 54) and the hammering of the first impacting groupware (36; 40, 46, 50, 54) are stagger, and the intermediate shaft (26) hammers twice in each rotation cycle. In the manipulation process, the impacting blocks move oppositely, which raises the hammering efficiency.

Description

Electric hammer

Technical Field

The utility model relates to a hammer instrument, especially a hammering subassembly structure of motor drive's hammer instrument.

Background

Currently, there are a wide variety of electric hammers on the market that are used by domestic or professional users for surface cleaning on walls or ceilings. Hammering is typically accomplished by a motion conversion mechanism that converts rotation of the intermediate shaft into longitudinal reciprocating movement of the drill bit. Similar motion conversion mechanisms typically include a hammer assembly on the one hand and a counterweight that moves in opposition to the bit on the other hand. It must be emphasized that in this design, only one impact is obtained per revolution of the intermediate shaft and the energy acting on the counterweight is wasted.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide a motor-driven hammer, in particular an electric hammer that can improve hammering efficiency.

It is another object of the present invention to provide a hammer type tool that reduces energy loss during operation.

According to the utility model discloses, a hammer, including casing, motor, hammering instrument, first impact block, second impact block, first hammering subassembly mechanical connection to the motor is used for first impact block striking hammering instrument, and second hammering subassembly mechanical connection to the motor is used for second impact block striking hammering instrument, the hammering of second hammering subassembly for the hammering of first hammering subassembly is used for mode that hammering takes place in turn staggers each other, and, first impact block and second impact block mutual reverse movement.

Since the two impact blocks are used for hammering, the hammering efficiency of the hammer type tool is increased, and health problems which may be caused to a user by vibration are suppressed.

Preferably, the first hammer assembly includes a rod of a predetermined first mass mounted in said housing for first reciprocation along said longitudinal axis, and the second hammer assembly includes a tube of a second predetermined mass mounted in said housing for second reciprocation along said longitudinal axis, said tube at least partially housing said rod.

In another preferred embodiment, the hammering assembly comprises first and second oscillating plates mounted on an intermediate shaft and connected to said rod and tube respectively, said hammering means thus receiving alternately the hammering action of said rod and tube. In this embodiment, the jackshaft produces two hammering effects every turn, therefore, the produced hammering quantity of jackshaft every turn doubles, compares with prior art, and the efficiency of hammer has doubled.

The vibrations acting on the operator are reduced, resulting not only in an increase in the comfort of use for the operator, but also in an increase in the accuracy of the work performed.

It is worth noting that the arrangement of the swing plate mounted on the intermediate shaft represents a mechanism for reciprocating the two impact blocks in opposite directions.

Preferably, the hammer assembly includes a resilient damping element therein for providing acceleration and damping of the impact mass.

Other preferred embodiments of similar arrangements are recited in the claims.

It is also worth emphasizing that the above described design can also be used for a hammer drill mechanism. In a similar mechanism, a transmission gear system may be connected to the motor, particularly to rotate the peening tool through the intermediate shaft.

Drawings

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 is a side cross-sectional view of an electric hammer in which a second impact block is retracted during the first impact block striking an impact block attached to a hammering tool;

FIG. 2 is a side view of the hammer shown in FIG. 1 taken along line II-II;

fig. 3 is a side cross-sectional view of the electric hammer shown in fig. 1, wherein the first impact block is retracted during the second impact block striking a hammer body connected to the drill bit;

FIG. 4 is a side cross-sectional view of the hammer drill corresponding to FIG. 1;

FIG. 5 is a side cross-sectional view of the hammer drill corresponding to FIG. 3;

FIG. 6 is a schematic perspective view of the gear system;

FIG. 7 is a top plan view of a drive mechanism incorporating the gear system of FIG. 6;

FIG. 8 is a schematic perspective view of another gear system;

FIG. 9 is a top plan view of a drive mechanism incorporating the gear system of FIG. 8;

FIG. 10 is a side view of a hammer incorporating the drive mechanism of FIG. 9;

FIG. 11 is a schematic view taken along the line XI-XI in FIG. 10;

FIG. 12 is a perspective view of another gear system;

FIG. 13 is a top plan view of a drive mechanism incorporating the gear system of FIG. 12;

FIG. 14 is a perspective view of another gear system similar to that of FIG. 8;

FIG. 15 is a top plan view of a drive mechanism incorporating the gear system of FIG. 14;

FIG. 16 is another gear system similar to the gear system of FIG. 6, connected to the slide plate of FIG. 15;

fig. 17 is a schematic top view of another hammer embodiment of the present invention;

FIG. 18 is a side view of the hammer of FIG. 17;

fig. 19 is a schematic view along the Z-Z direction in fig. 18.

Wherein,

2 housing 4 hammering tool 6 impact block

8 chuck 10 plane side 12 guide tube

14 longitudinal axis 16 first impact block 20 second impact block

24 motor 26 intermediate shaft 27 motor shaft

28 motor pinion 30 gear 32 ball bearing

34 first hammer assembly 36 second hammer assembly 38 first swing plate

40 second swing plate 42 swing plate drive 44 first swing arm

46 second swing arm 48 first ball end 50 second ball end

52 receiving hole 54 receptacle 56 connector

58 first side wall 60 and second side wall 62 connect the arms

64 slot 66 intermediate pinion 68 transfer gear

70 first gear 72 first axis 73 arrow

74 first pin 76 first slide 78 first guide slot

79 first attachment means 81 attachment means of arrow 80

82 second gear 84 second axis 85 arrow

86 second pin 88 second slide 90 second guide slot

91 arrow 92 second attachment means 94 leading to the side wall

96 guide sidewall 98 pinion 100 sliding retainer

102 slide pin 104 link assembly 104a link

104b link 104c link 104d link

106 elongate plate 108 guide slot 110 first slide

112 second slide 114 first non-circular slide 116 first non-circular slide

120 second impact block channel 122 center rod 123 first attachment mechanism

124 teeth 125 on the center rod lift the arm 126 first transfer gear

127 arrow 128 second transfer gear 130 first fixed axis

132 second fixed axis 134 first side bar 134a first support bar

134b first small connecting element 136a second side bar 136a second support bar

136b second small connecting element 137, teeth on the arrow 138 stem

Teeth 142 on 139 arrow 140 rod second attachment mechanism

144 side arm 146 side arm m1 first mass

m2 second Mass I1 first Length I2 second Length

Detailed Description

Referring to fig. 1-3, the present invention discloses an electric hammer. The electric hammer includes a housing 2, and a hammering tool 4 extending from the housing 2. The hammering tool 4 is a conventional hammer drill bit, such as a standard SDS PLUS or SDS MAX drill bit. The hammering tool 4 is optionally connected to a cylindrical impact block 6 by a collet 8. The impact block 6 has a flat side 10 opposite the collet 8, housed in a guide tube 12 firmly attached to the front wall of the housing 2. The longitudinal axis is indicated at 14 and during operation, the hammering action occurs along the longitudinal axis 14.

By means of the first impact block 16 and the second impact block 20, a hammering action is achieved. The first impact block 16 may be in the form of an elongated rod having a predetermined first mass m 1. The second impact block 20 may be in the form of a tube having a predetermined second mass m2 and at least partially housing the first impact block 16. Preferably, the first mass m1 is approximately equal to the second mass m 2. Since m1 is m2, the second impact mass 20 may be considered as a counterweight to the first impact mass 16, and vice versa. The two impact blocks 16, 20 are movable relative to the housing 2 along the longitudinal axis 14. The ends of the two impact blocks 16, 20 are smaller than the plane side 10 of the impact block 6.

The

hammering assemblies

34, 36 include damping elastic members (not shown) for accelerating the impact velocity of the impact block 6 while being capable of damping the impact applied to the support member. Due to the arrangement of the damping elastic element, the motion trajectories of the first impact block 16 and the second impact block 20 are not completely symmetrical. When the first impact block 16 impacts the impact block 6, the first impact block 16 is moved towards the impact block 6 at the second impact block 20 under the action of the damping elastic element, resulting in an extremely short time of damping. Similarly, the second impact block 20 will have a corresponding action. Thus, the first impact block 16 and the second impact block 20 move in opposition to each other for a substantial portion of the time during impact.

Through a gear train, the motor 24 rotates the intermediate shaft 26. The motor 24 includes a motor shaft 27, a motor pinion 28, and a gear 30. The motor 24 may be replaced by a pneumatic motor. The intermediate shaft 26 is supported by a ball bearing 32 in the housing 2.

The first hammer assembly 34 is driven by the intermediate shaft 26, and the first impact block 16 produces a hammering action on the hammering tool 4 along the longitudinal axis 14 by means of the impact block 6. The second hammer assembly 36 is also driven by the intermediate shaft 26, and the second impact block 20 impacts the hammer tool 4 along the longitudinal axis 14 via the impact block 6. It is important that the hammering action of the second hammer assembly 36 be staggered relative to the hammering action of the first hammer assembly 34 so that a total of two hammering actions occur during each revolution of the intermediate shaft 26. During operation, the impact blocks 16, 20 move in opposite directions to each other, thereby damping vibrations.

In the preferred embodiment of the present invention, as shown in fig. 1-3,

hammer assemblies

34, 36 include first and

second wobble plates

38, 40, respectively, interconnected by a wobble plate drive 42. A similar design is known from us patent publication No. 5025562. First and

second swing arms

44, 46 are attached to the

swing plates

38, 40, respectively, and are disposed at a predetermined angle to each other. Thus, throughout the rotation of the intermediate shaft 26, the axes of the

swing arms

44, 46 tilt away from each other and towards each other. The swing translation of the swing arm is converted into a longitudinal movement of the impact blocks 16, 20, indicated by small arrows parallel to the longitudinal axis 14 and opposite to each other.

It is noted that the first swing arm 44 is longer than the second swing arm 46. Assuming that the mass of the first impact block 16 is m1, the mass of the second impact block 20 is m2, the length of the swing arm 44 is I1, and the length of the swing arm 46 is I2, in order to cancel vibrations, the corresponding mass m1, m2 should be adjusted so that m1 × I1 is m2 × I2. The

swing arms

44, 46 are provided with ball ends 48 and 50, respectively.

The first ball end 48 is movably received within the cavity of the bore 52 of the first impact block 16 such that the first axis of back and forth motion is translated into longitudinal movement along the longitudinal axis 14. And, the second ball end 50 is movably received in a chamber 54 formed at a lower portion of a connector 56, and the connector 56 is firmly attached to the second impact block 20. Referring to fig. 2, the connector 56 is formed by two parallel side walls 58, 60, the two side walls 58, 60 being connected to each other by a connecting arm 62. The tubular impact block 20 is provided with a groove 64 along its lower wall portion. The slot 64 extends all the way along the tube 20, and the first swing arm 44 extends through the slot 64 into the receiving hole 52.

As shown in fig. 1, the outer end of the first impact block 16 will hit the impact block 6, thereby pushing the hammering tool 4 towards a workpiece, such as a concrete wall (not shown). And as shown in fig. 3, after each rotation of the intermediate shaft 26 by more than 180 °, the outer end of the second impact block 20 will also strike the impact block 6 after retraction of the first impact block 16, thereby again pushing the hammering tool 4 towards the workpiece, so that two hammering events occur during each rotation of the intermediate shaft 26.

Suppose a dc motor provides 12000 rpm. The frequency of hammering may be different based on the gear ratio of the

gear systems

28, 30. For example, the intermediate shaft 26 may rotate at a speed of 3000 rpm, resulting in 6000 blows per minute.

Fig. 4 and 5 disclose a hammer drill, which is of a design substantially similar to that described in fig. 1-3, but which at the same time is capable of rotating the hammering tool 4. At this time, the intermediate pinion 66 is attached to the intermediate shaft 26 for driving the transmission gear 68 that rotates the hammering tool 4 at the time of hammering, and the

transmission gear system

66, 68 may have a gear ratio of 3: 1.

Fig. 6 to 19 disclose further embodiments of further mechanisms for reciprocally moving the two impact blocks 16, 20 in opposite directions. In some of these figures, the impact blocks 16, 20 themselves are not shown.

According to fig. 6 and 7, first hammer assembly 34 includes a thick first gear 70 which rotates relative to a first axis 72 fixed to housing 2, with arrow 73 indicating clockwise rotation. A small first pin 74 is attached to the outer region of the first gear 70. First hammer assembly 34 also includes a first slide plate 76 having a first guide slot 78. The first pin 74 extends into the first guide slot 78. The first gear 70 rotates and the first slide plate 76 reciprocates in the direction of the longitudinal axis 14, the direction of movement being indicated by arrow 79 pointing to the right in FIG. 7. First attachment means 80 is provided for attaching first impact block 16 (not shown) to first slide plate 76.

Second hammer assembly 36 includes a thin second gear (82) that rotates relative to a second axis 84 fixed to housing 2, with arrow 85 indicating counterclockwise rotation. The

axes

72 and 84 are parallel to each other. A small second pin 86 is attached to an outer region of the second gear 82. Second hammer assembly 36 also includes a second slide plate 88 having a second guide slot 90 parallel to first guide slot 78, and a second pin 86 extending into second guide slot 90. Notably, in fig. 7, the two

pins

74 and 86 are in an upward position. By rotating the second gear 82, the second slide plate 88 is also reciprocated in the direction of the longitudinal axis 14, but in an opposite direction relative to the first slide plate 76, the direction of movement being indicated by the arrow 91 pointing to the left in fig. 7. Second attachment means 92 are provided for attaching second impact block 20 (not shown) to second sled 88.

According to fig. 7, two

guide elements

94 and 96 serve to guide the

slide plates

76 and 88 arranged therebetween during the longitudinal displacement of the slide plates in the direction of the longitudinal axis 14.

The

gears

70, 82 are driven in anti-phase rotation (as indicated by arrows 73, 85) by a pinion 98 connected to the motor 24 by the motor shaft 27. When the upper portion of the first gear 70 is engaged with the second gear 82, the lower portion of the first gear 70 is engaged with the pinion 98.

The embodiment shown in fig. 8 and 9 is the same as the embodiment shown in fig. 6 and 7, however, here the pinion 98 is located between the

gears

70 and 82, the pinion 98 meshing with the first gear 70 and also with the second gear 82. The two gears 70 and 82 have the same thickness. As a result, the two

gears

70, 82 rotate clockwise as indicated by

arrows

73, 85. Here, the two

pins

74, 86 are spaced 180 ° apart. Thus, when the second pin 86 is in the lower position, the first pin 74 is in the upper position in fig. 9. As a result, the

slide plates

76, 88 always move in opposite directions to each other as indicated by

arrows

79, 91.

Fig. 10 is a side view of fig. 8 and 9, the present invention being attached to the first impact block 16 and the second impact block 20, respectively, and fig. 11 is a schematic view in the direction XI-XI of fig. 10. According to fig. 10 and 11, the first impact block 16 is a tube, while the second impact block 20 is a compact cylindrical piece sliding in the tube. The first attachment device 80 may be in the form of a link 56 similar to that shown in fig. 2, having two side arms and at least one link arm. And the second attachment means 92 may be a connecting rod leading from the second slide plate 88 to the second impact block 20 through the longitudinal slot 64 in the lower portion of the tube 16.

Fig. 12 and 13 disclose another embodiment of the drive mechanism. In fig. 6 to 11, the first hammer assembly 34 is provided with a gear 70 for rotation relative to an axis 72 fixed to the housing 2. Gear 70, having pin 74, is driven by motor 24 through motor shaft 27 and pinion 98 to rotate in the direction indicated by arrow 73. The first slide plate 76 is slidable between the two

side walls

94 and 96 in the direction of the longitudinal axis 14. The first slide plate 76 is provided with a first guide groove 78 at its center for receiving the pin 74. First attachment means 80 for attaching first impact block 16 and attachment means 81 for attaching second hammer assembly 36 are provided on first slide plate 76. Second hammer assembly 36 includes a second slide plate 88 provided with a second guide slot 90. It has to be noted that the second slide plate 88 is fixed with respect to the housing 2 and the second guide groove 90 is arranged perpendicularly with respect to the first guide groove 78.

A sliding holder 100 is provided in the form of an elongated plate or disc. On the left side of the slide holder 100 in fig. 13, a slide pin 102 is provided to protrude into the second slot 90 for longitudinal sliding movement. Second attachment means 92 are provided for attaching the second impact block 20 to the sliding holder 100.

To transfer kinetic energy to first and

second hammer assemblies

34, 36, respectively, linkage assembly 104 is in communication with an elongated plate 106 disposed between first and

second hammer assemblies

34, 36. The elongated plate 106 is fixed with respect to the casing 2 and is provided in its centre with a guide slot 108 for receiving two

slides

110, 112 provided at the upper and lower corners of the connecting-rod assembly 104. The link assembly 104 has four movable links arranged in a quadrilateral shape. It can be seen that as the motor 24 rotates, the

devices

80, 92 will move in opposite radial directions in the directions indicated by

arrows

79, 91.

The embodiment disclosed in fig. 14 and 15 is similar to the embodiment disclosed in fig. 8 and 9. First hammer assembly 34 includes a first gear 70 rotatable relative to a first axis 72 fixed to housing 2. The first gear 70 is driven by the motor 24 through the motor shaft 27 and the pinion 98. The direction of rotation of the first gear 70 is indicated by arrow 73. Attached to the top of the first gear 70 is a first non-circular slider 114 that is asymmetrically disposed with respect to the first axis 72. As shown in FIG. 15, the first slide plate 76 is substantially O-shaped having a first guide slot 78 for receiving a first non-circular slider 114. Furthermore, a first attachment device 80 is provided on the first slide plate 76, the attachment device 80 connecting the first impact block 16 to the first slide plate 76 such that the first impact block 16 can move longitudinally in the direction indicated by arrow 79.

Second hammer assembly 36 includes a second gear 82 rotatable relative to a second axis 84 fixed to housing 2. The second gear 82 is also driven by the motor 24 through the motor shaft 27 and the pinion 98. A second non-circular slider 116 is connected to the top of the second gear 82 and rotates relative to the second axis 84. A second slide plate 88 is provided having a second guide slot 90 centrally disposed therein for receiving a second non-circular slider 116 slidable along an inner periphery. A second attachment device 92 is attached to the top of the second slide plate 88 for attaching the second impact block 20 to the second slide plate 88.

As can be seen in fig. 14 and 15, the

slides

114 and 116 are substantially oval and are non-concentrically connected to the

respective gears

70 and 82. Likewise, the

slides

114 and 116 are disposed 180 ° out of phase with each other. Thus, a reverse linear movement is generated as indicated by

arrows

79 and 91.

The embodiment of fig. 16 is very similar to the embodiment shown in fig. 6, with the pinion 98 meshing with the first gear 70, and the first gear 70 meshing with the second gear 82 having a smaller thickness. Substantially

elliptical slides

114, 116 are attached to the top of

gears

70 and 82, respectively, for effecting opposing linear movements of

slides

76 and 88.

Referring to fig. 17-19, a motor driven hammer having a first hammer assembly 34 driving a first impact block 16 and a second hammer assembly 36 driving a second impact block 20. The two impact blocks 16, 20 may be rectangular. As shown in fig. 19, the first impact block 16 may most preferably be a block that can be inserted and guided into the U-shaped channel 120 of the second impact block 20, whereby the two impact blocks 16 and 20 alternately strike the impact block 6.

In the first hammer assembly 34, the gear 70 rotates relative to the axis 72, the axis 72 being fixed to the housing 2. The gear 70 is externally provided with a pin 74. Gear 70 is driven by motor 24 through motor shaft 27 and pinion 98. A slide plate 76 is also provided having a guide slot 78 in the center thereof for receiving the pin 74. First peening assembly 34 here is similar to first peening assembly 34 disclosed in fig. 12 and 13.

The center rod 122 is connected to the slide plate 76, and the longitudinal axis of the center rod 122 is perpendicular with respect to the axis of the guide groove 78. The attachment means may be any feasible means, such as welding 123. The two

elements

76 and 122 may also be made of one piece. At the other end of the central rod 122, a first impact block 16 is connected via a lifting arm 125. Based on this design, the first impact block 16 reciprocates in the direction of the longitudinal axis of the central rod 122, as indicated by arrow 27.

The center rod 122 has teeth 124 on both sides, and a first transfer gear 126 and a second transfer gear 128 rotate relative to a first axis 130 and a second axis 132, respectively, and mesh with the teeth 124. The

axes

130 and 132 are fixed to the housing 2.

Second hammer assembly 36 includes two

side rods

134 and 136, disposed parallel to central rod 122. The side bars 134 and 136 are provided with

teeth

138 and 140 all the way into engagement with the drive gears 126 and 128, respectively. The side bars 134 and 136 are slidably mounted on the support bars 134a and 136a and are in turn fastened to the casing 2 by means of small connecting

elements

134b and 136b, respectively. Thus, the side bars 134 and 136 move in opposition to the center bar 122, as indicated by

arrows

137 and 139.

The side bars 134 and 136 are connected to the second impact block 20 by second attachment means 142. The second attachment device 142 includes two

side arms

144 and 146. It can be seen that the

side arms

144 and 146 lift the second impact block 20 above the common plane in which the central bar 122 and the side bars 134, 136 lie.

It is noted that the central rod 122 is driven by the gear 70 and moves from left to right and vice versa with respect to fig. 17. The drive gears 126 and 128 transfer linear movement from the center rod 122 to the

side rods

134 and 136 and transfer motion to the second impact block 20 through the

side arms

144 and 146. In this way, the first impact block 16 and the second impact block 20 periodically alternately strike the impact block 6 and transmit the strike to the hammering tool 4.

Claims

1. A hammer, comprising: -a housing (2), -a drive motor (24), -a hammering tool (4), -a first impact block (16), -a second impact block (20), -a first hammering assembly (34) mechanically connected to the motor (24) for the first impact block (16) to strike the hammering tool (4), and-a second hammering assembly (36) mechanically connected to the motor (24) for the second impact block (20) to strike the hammering tool (4), -the hammering action of the second hammering assembly (36) is mutually staggered with respect to the hammering action of the first hammering assembly (34) in such a way that the hammering occurs alternately, and-the first impact block (16) and the second impact block (20) move mutually in opposite directions.

2. The hammer of claim 1, wherein the first hammer assembly (34) includes a rod (16) having a first mass (m1) mounted on the housing (2) for reciprocating along the longitudinal axis (14), and the second hammer assembly (36) includes a tube (20) having a second mass (m2) for reciprocating along the longitudinal axis (14), the tube (20) being mounted in the housing (2) and at least partially housing the rod (16).

3. Hammer according to claim 1 or 2, wherein an impact block (6) is provided along the longitudinal axis (14), the hammering movement of the first and second hammering assemblies (34, 36) being transmitted to the hammering tool (4).

4. Hammer according to claim 3, characterized in that the impact block (6) has a side (10) facing the first impact block (16) and the second impact block (20), the side (10) being larger than the diameter of each of the first impact block (16) and the second impact block (20).

5. Hammer according to claim 4, characterized in that each hammering assembly (34, 36) comprises at least one swing arm (44, 46) extending towards the rod (16) and the tube (20), respectively.

6. The hammer of claim 5, wherein the first swing arm (44) of the first hammer assembly (34) has a first ball end (48) received in a bore (52) on the rod (16), and the second swing arm (46) of the second hammer assembly (36) has a second ball end (50) rotatably received in a connector (56), the connector (56) mating with the tube (20).

7. Hammer according to claim 6, characterized in that the connecting element (56) has two side walls (58, 60) which are coupled to a connecting arm (62).

8. Hammer according to claim 1, characterized in that the motor is an electric or pneumatic motor.

9. Hammer according to claim 8, characterized in that a transmission gear system (66, 68) is connected to the motor (24), which rotates the hammering tool (4) via an intermediate shaft (26) rotatably mounted in the housing (2).

10. Hammer according to claim 9, characterized in that the intermediate shaft (26) generates a total of two hammering movements per revolution.

11. Hammer according to claim 10, characterized in that the hammering assembly (34, 36) comprises a first oscillating plate (38) and a second oscillating plate (40) mounted on the intermediate shaft (26) and coupled respectively to the rod (16) and to the tube (20), the hammering tool (4) being alternately subjected to the hammering action of the rod (16) and of the tube (20).

12. Hammer according to claim 1, characterized in that the first hammering assembly (34) comprises a first gear wheel (70) rotating with respect to a first axis (72) fixed to the housing (2), a first pin (74) coupled with the first gear wheel (70), a first sliding plate (76) provided with a first guide slot (78) and intended to receive the first pin (74), and a first attachment means (80) connecting the first impact block (16) to the first sliding plate (76), and in that the second hammering assembly (36) comprises a second gear wheel (82) rotating with respect to a second axis (84) fixed to the housing (2), a second pin (86) coupled with the second gear wheel (82), a second sliding plate (88) provided with a second guide slot (90) and intended to receive the second pin (86), and a second attachment means (92) connecting the second impact block (20) to the second sliding plate (88).

13. Hammer according to claim 12, characterized in that it further comprises at least one guide (94, 96) for guiding the slide plates (76, 88) during their mutual opposite movement.

14. Hammer according to claim 12 or 13, characterized in that it is also provided with a pinion (98) to rotate the first (70) and second (82) gears.

15. The hammer of claim 14, wherein the pinion gear (98) is in mesh with the first gear (70) and the first gear (70) is in mesh with the second gear (82).

16. Hammer according to claim 14, characterized in that the pinion (98) meshes with the first (70) and second (82) gears.

17. Hammer according to claim 1, characterized in that the first hammering assembly (34) comprises a first gear wheel (70) rotating with respect to a first axis (72) fixed to the housing (2), a first pin (74) coupled with the first gear wheel (70), a first sliding plate (76) provided with a first guide slot (78) and intended to receive the first pin (74), and first attachment means (80) connecting the first impact block (16) to the first sliding plate (76), the second hammering assembly (36) comprises a fixed second sliding plate (88) provided with a second guide slot (90), a holder (100) of the sliding pin sliding longitudinally in the second guide slot (90), second attachment means (92) for connecting the second impact block (20) to the sliding holder (100), and a linkage assembly (104) converting the longitudinal movement of the first sliding plate (76) into the sliding holder (100) Longitudinal movement in the opposite direction.

18. The hammer of claim 17, wherein the linkage assembly (104) includes four linkages (104a, 104b, 104c, 104d) configured as a quadrilateral, at least one slide (110, 112), and a fixed elongate plate (106) having a guide slot (108) that receives the slide (112).

19. Hammer according to claim 17 or 18, characterized in that it is also provided with a pinion (98) to rotate the first gear (70).

20. The hammer of claim 1, wherein the first hammer assembly (34) includes a first gear (70) rotatable relative to a first axis (72) fixed to the housing (2), a first non-circular slide (114) coupled to the first axis (72), a first slide plate (76) provided with a first guide slot (78) for receiving the first non-circular slide (114), and a first attachment device (80) connecting the first slide plate (76) to the first impact block (16), and the second impact assembly (36) includes a second gear (82) rotatable relative to a second axis (84) fixed to the housing (2), a second non-circular slide (116) coupled to the second axis (84), a second slide plate (88) provided with a second guide slot (90) for receiving the second non-circular slide (116), and second attachment means (92) for connecting said second impact block (20) to said second skid plate (88).

21. Hammer according to claim 20, characterized in that it is further provided with a pinion (98) to rotate the first (70) and second (82) gears.

22. The hammer of claim 21, wherein the pinion gear (98) is in mesh with the first gear (70) and the first gear (70) is in mesh with the second gear (82).

23. Hammer according to claim 21, characterized in that the pinion (98) meshes with the first gear (70) and the second gear (82).

24. Hammer according to any one of claims 20-23, characterized in that at least one of the slides (114, 116) has an approximately oval shape.

25. A hammer according to claim 1, wherein the first hammering assembly (34) comprises a central rod (122) movable back and forth, a first attachment mechanism (123) for connecting the first striker (16) to the central rod (122), and the second hammering assembly (36) comprises at least one side rod (134, 136) movable back and forth parallel to the central rod (122) but in opposite directions, a connecting means (126, 128) for connecting the second hammering assembly (36) to the first hammering assembly (34) by transmitting linear movement of the central rod (122) to linear movement of the side rod (134, 136), and a second attachment mechanism (142) for connecting the second striker (20) to the side rod (134, 136).

26. Hammer according to claim 25, wherein the first hammering assembly (34) comprises a gear wheel (70) rotating about a fixed axis (72), a sliding pin (74) arranged laterally to the gear wheel (70), and a sliding plate (76) cooperating with the sliding pin, wherein the central rod (122) has at least one first tooth (124) and is connected to the sliding plate (76), and wherein the second hammering assembly (36) comprises a lateral rod (134, 136), wherein the lateral rod (134, 136) has at least one second tooth (138, 140) engaging with the transmission gear (126, 128).

27. A hammer according to claim 26, characterized in that the central and lateral rods (122, 134, 136) are parallel to each other and the transmission gear (126, 128) has a fixed axis (130, 132) and is disposed between the central rod (122) and the lateral rods (134, 136).

28. Hammer according to any one of claims 25-27, characterized in that it is provided with a motor pinion (98) driving the gear wheel (70).

29. Hammer according to any one of claims 25-27, characterized in that the second attachment mechanism (142) comprises two lifting side arms (144, 146).

30. Hammer according to claim 1, characterized in that the second impact block (20) comprises a channel (120) for the passage of the first impact block (16).

31. The hammer of claim 1, wherein the hammer assembly (34, 36) further includes a damping spring element.