EP2251488B1 - Tamper for soil compaction - Google Patents

Description

introduction

The invention relates to a ramming device for soil compaction, with a pounding driven working mass which is linearly reciprocally movable from an engine belonging to an upper mass via a crank mechanism and a spring set, wherein the spring set at least one compressible at a forward movement of the piston first spring and at least having a compressible in the movement of the piston second spring.

For the purposes of the present application, "downward movement" and "movements" can be understood as either the downward work on the work to be compacted or the oppositely directed return movement of the work mass before the next work stroke.

State of the art

A ramming device of the type described above, for example, from EP 1 012 403 A known. The above document is concerned with the problem of vibrations of the upper mass, which adversely affect the operation of the ramming the operator, to avoid as far as possible. The starting point of the solution according to the EP 1 010 403 A consists in reducing the mass of the components of the upper mass, in particular the connecting rod, the guide piston and the piston guide. The proposal here is the execution of a lightweight construction in the form that in comparison to steel lighter materials are used, in particular aluminum alloys or plastic materials.

Furthermore, from the DE 1 925 870 A Another known ramming device, in which the upper mass is equipped with two parallel and opposite to each other working crank gears and the working mass with two parallel juxtaposed spring sets, both of which work in parallel and synchronously. Both spring sets each have only a single spring, so that a lack of tension and pressure connection "lifting" or "detachment" of the piston and spring can occur.

The known ramming devices are, in particular for use in close working environment, for example, for the trench insert provided. It is therefore positive if such rammers are made as small and lightweight as possible in order to facilitate their handling for the operator. This is especially true when working with such rammers under Verbaustreben or obliquely under pipes in trenches. In particular, the length is in such a cramped space of disadvantage, since it makes an unfavorable inclination of the device at low available height required. In this respect, it would be desirable to reduce the height of the known ramming devices, but with the piston should be acted upon in its movement in both directions with spring force.

A ramming device according to the preamble of claim 1 is known from DE 197 39 743 A1 known.

task

The invention has for its object to provide a ramming device with reduced height, especially in the field of pounding work mass, as height reductions in the range of the crank mechanism having upper mass are very narrow limits.

solution

Based on a ramming device of the type described above, the above object is achieved in that the at least one second spring, viewed in the direction of the reciprocating motion, is disposed within a free space in the interior of the at least one first spring.

The ramming device according to the invention thus dissolves from the dogma existing since the beginning in the construction of such devices that the compression springs acting on the piston from opposite directions, viewed lengthwise, are simply arranged one behind the other. From the addition of the axial lengths of the springs in the prior art namely results in a large height of the working mass and thus of the ramming device as a whole. Here, the invention remedy the fact that the axial length of the springs only partially or in the extreme case no longer add, but that there is a kind of "nesting" or "overlap". The term "overlap" is not to be understood literally, but in particular means the telescoping meshing coaxially arranged springs, whereby the axial length of the spring set can be significantly reduced. In this case, the principle remains that both during the outward and during the reciprocation of the piston each compressed at least one spring and at least one other spring is relaxed, unchanged, so that in principle nothing changes in the vibration behavior of the ramming device. In particular, at the DE 919 25 870 A occurring Abhebeerscheinungen not occur. The short axial length of the nested spring assembly also allows the realization of short and therefore slender connecting rods, whereby the oscillating masses can be lowered and consequently the hand / arm vibrations can be reduced for the user.

For structural reasons, it is advantageous if, in the case of only partial axial meshing of the two springs, the inserted, that is to say inner first spring, is arranged closer to an underside of the ramming device facing the substrate to be compacted than at least one second spring.

A particularly advantageous design is that all the springs are coaxial with each other arranged coil springs, wherein an outer diameter of the at least one first spring is smaller than the inner diameter of the at least one second spring. An arrangement of the feathers can be achieved in this way particularly easy.

An inventive possibility for structural design of the piston is that it has a cup shape, two mutually Wegweisende end faces for supporting the at least one first spring and the at least one second spring and in an overlap region of the springs between the at least one first spring and the at least a second spring is arranged, wherein in the overlap region between the springs an essentially filled by the piston annular space.

It is also advantageous if the piston has an upper tubular portion and a lower tubular portion, wherein the lower portion has a relation to the upper portion of larger diameter.

In connection with the aforementioned pot shape of the piston, it makes sense if the upper mass has an outer guide tube in which an inner guide tube of the working mass is linearly reciprocally movable, wherein an outer circumferential surface of the inner guide tube slidably with an inner circumferential surface of the outer guide tube is in contact, wherein preferably the inner guide tube has two spaced-apart mutually facing end faces on which the at least one first spring and the at least one second spring are each supported with its output side end. The output-side end is to be understood in each case as the end, which - viewed in the direction of the force flow - faces a contact element to be arranged on the ground contact element. By the inner guide tube, the bending moments and transverse forces that occur during operation of the rammer, recorded so that wear of the outer guide tube is significantly reduced. Consequently, the robustness of the ramming device according to the invention is significantly increased by the arrangement of the inner guide tube.

It is expedient if the first spring is arranged within a space delimited by an inner circumferential surface of the inner guide tube and an outer circumferential surface of the piston, and the second spring is arranged within a tubular end section of the piston.

A constructive alternative to a pot piston, that is to say a sleeve-shaped piston with flange faces for the springs, consists in that the piston has two pressure elements which are spaced apart from each other and coupled to each other via a piston rod, in particular radially outwardly over the piston rod projecting pressure plates, the two toward each other facing end faces for supporting the at least one first spring and the at least one second spring and is arranged in an overlapping region of the springs within a free space of the innermost spring.

In this alternative construction with respect to the piston design, the upper mass may have an outer guide tube, but in deviation from the design of a pot piston in the guide tube, the piston and a guide member of the inner guide tube are linearly reciprocally movable, wherein an inner circumferential surface of the outer Guide tube slidably both with an outer circumferential surface of the piston, in particular its upper mass facing the pressure plate, as well as with an outer circumferential surface of an outer surface of the inner guide tube radially outwardly projecting guide member, in particular in the form of a guide ring in contact. In this case, the inner guide tube has a first support surface arranged in its interior for the at least one first spring and a second support surface projecting radially outward beyond its outer jacket surface for the at least one second spring. Preferably, furthermore, the second support surface is formed by the guide member, that is in particular the guide ring.

The underlying object is also starting from a ramming device for soil compaction with a pounding driven working mass, which is linearly reciprocally movable from a belonging to an upper engine engine via a crank mechanism and a spring set, the spring set both in the outward and in the movement transmits a resultant force to the working mass, solved in that all the springs of the spring set in the forward movement of the piston compressive forces and in the movement of the piston tensile forces transmitted to the working mass.

In this alternative design principle, which is characterized as the solution described above by its short axial length and therefore allows the production of short-ramming ramming, it is waived that at an axial movement between the upper mass and working mass always simultaneously shortened at least one spring in length, however at least one further spring is increased in length. In the alternative principle according to the invention, therefore, all the springs are always loaded in the same manner, that is to say either on train or on pressure, so that in the course of the direction reversal of the relative movement between the upper mass and the working mass a change of sign occurs in the spring force, that is to say a change of tension. on compressive forces and vice versa. To the structural design of the springs of the spring set in such a Although high demands are placed on the principle in order to achieve the required fatigue strength, this difficulty is more than compensated by the advantages in terms of cost, weight and size of the working mass.

In a particularly simple design variant of this invention principle of the spring set consists of a single spring, which is preferably designed as a helical spring.

A particularly simple way of fastening the springs is that all the springs are coil springs and each secured to an end of the upper mass with an end portion of its wire secured in a bore in the piston and at one end facing the working mass with an end portion of their Secure secured wire in a hole in an inner guide tube of the working mass. In this case, an outer circumferential surface of the inner guide tube is axially slidably in contact with an inner circumferential surface of an outer guide tube of the upper mass. The attachment of the springs on the wire ends in corresponding holes of the adjacent force-transmitting components allows in a simple manner the mandatory in this principle change between a tensile force and compressive force transmission.

The invention further ausgestaltend is provided that between a first support surface of the piston and a first support surface of the inner guide tube, a first damping element is arranged, which surrounds a radially outer portion of the upper mass facing the outer mass, and that between a second support surface of the piston and a second Support surface of the inner guide tube, a second damping element is arranged, which is located in the interior of the spring set, in particular in the interior of the single spring, in particular in the form of a helical spring. The damping elements are selected in their axial length so as to prevent the turns of a spring from being compressed to "block" and, secondly, during the pulling phase, the piston to the second end face of the inner guide tube in the form of direct metallic contact collided.

Figur 1

eine erste Ausführungsform eines Stampfgeräts mit einem Topfkolben im Längsschnitt,

Figur 2

wie Figur 1, jedoch in einem um 90° gedrehten Längsschnitt,

Figur 3

eine zweite Ausführungsform eines Stampfgerätes mit einem Doppelteller-Kolben im Längsschnitt,

Figur 4

wie Figur 3, jedoch in einem um 90° gedrehten Längsschnitt,

Figur 5

eine dritte Ausführungsform eines Stampfgeräts mit einer einzigen kombinierten Zug-Druck-Feder im Längsschnitt und

Figur 6

wie Figur 5, jedoch in einem um 90° gedrehten Längsschnitt.

The invention will be explained in more detail below with reference to three exemplary embodiments of ramming devices which are illustrated in the drawing, in which:

FIG. 1

a first embodiment of a ramming device with a pot piston in longitudinal section,

FIG. 2

as FIG. 1 but in a longitudinal section rotated by 90 °,

FIG. 3

a second embodiment of a ramming device with a double-plate piston in longitudinal section,

FIG. 4

as FIG. 3 but in a longitudinal section rotated by 90 °,

FIG. 5

a third embodiment of a ramming device with a single combined tension-compression spring in longitudinal section and

FIG. 6

as FIG. 5 , but in a 90 ° rotated longitudinal section.

One in the FIGS. 1 and 2 in 90 ° against each other rotated longitudinal sections illustrated ramming device 1 for soil compaction has equipped with an internal combustion engine, not shown upper mass 2 and an elastically via a spring set 3 so coupled working mass 4, which is connected at its lower end with a foot adapter 5. The foot adapter 5 is connectable on its underside by means of screws with a ground contact element, not shown, made of a wear-resistant material. On the opposite side adjoins the foot adapter 5 at the top of a foot tube 6, which is also referred to as a "lower flange" and as an arranged on the upper mass upper flange 7 for clamping attachment of a rubber-elastic bellows 8, with the under compensation the occurring length changes the mechanics in the field of the spring set 3 is protected from the harsh on construction sites environmental conditions, especially from dirt and water. Inside the bellows is a partial filling with oil to permanently lubricate the sliding parts.

About an unillustrated pinion whose axis of rotation is illustrated by the dashed line 9, a gear 10 is driven by the motor that has an eccentrically arranged crank pin 11 to which a connecting rod 12 is connected with the interposition of a rolling bearing with its upper eye 13. The lower eye 14 of the connecting rod 12 also acts with the interposition of a bearing with a piston pin 15 of a piston 16 designed as a pot piston together. Apart from the pot shape of the piston 16 according to the invention, the previously described components of the ramming device 1 are known in this form from the prior art and therefore need no further explanation. The same applies to the resulting from the crank mechanism oscillating stroke movement of the piston 16, which leads via the spring set 3 to a corresponding oscillating movement of the working mass 4 and thus the foot adapter 5 and the ground contact element connected there.

The spring set 3 consists of a larger diameter and thus outer, first spring 17 and a smaller diameter and thus inner, second spring 18. The first spring 17 is supported with its lower, pointing away from the upper mass 2 end to a lower end face nineteenth of the piston 16, which is formed by a radially outwardly projecting lower flange portion. With its opposite upper end, the first spring 17 is supported on an end face 20, which is shown on an upper cover 21 of an inner guide tube 22 of the working mass 4. In addition to the upper lid 21, the inner guide tube 22 also has a lower lid 23, wherein both covers 21 and 23 are fixedly connected to the inner guide tube 22, so that the overall result is the shape of a closed box or drum. Through an opening in the upper cover 21, the piston 16 enters with its upper smaller diameter portion 24 in the interior of the inner guide tube 22 a. Subsequent to a paragraph 25, a lower portion 26 of the piston 16 which is enlarged in diameter relative to the upper portion 24 closes. The paragraph 25 serves as a stop for a trained as a ring upper insulation element 27 which is disposed in the upper lid 21.

In the lower portion 26 of the piston 16 is the second spring 18, which is supported with its upper, the upper mass 2 end facing an intermediate cover 28 of the piston 16, wherein the intermediate cover in the transition region between the upper portion 24 and the lower portion 26th is arranged. The second spring 18 is supported at its opposite end on the lower cover 23 acting as the lower end face 29 of the inner guide tube 22. On the other hand, the intermediate cover 28 forms an end face 30 of the piston 16 on its underside.

A tapered upper part 31 of the lower lid 23 carries a second damping element 32 which, like the second spring 18, can also abut on the upper end face 30 of the piston 16 in order to prevent the spring 18 from being compressed to block.

The caused by the crank drive oscillating stroke movement of the piston 16 is thus transmitted via the two prestressed and always acting as compression springs 17, 18 on the inner guide tube 22 and thus causes the desired oscillating stroke movement of the working mass 4. Here, the inner guide tube 22 telescopically in one belonging to the upper mass 2 outer guide tube 33 slidably guided in the axial direction. In this case, an outer circumferential surface 34 of the inner guide tube 22 with an inner circumferential surface 35 of the outer guide tube 33 in contact.

It can be clearly seen that the piston 16, which is in the form of a pot or a sleeve, allows the two springs 17, 18 to be interleaved, whereby the axial length of the spring assembly 3 is significantly reduced compared to a simple linear arrangement known from the prior art that overall the height of the ramming device 1 is reduced, which improves its use in confined spaces.

In the in the Figures 3 and 4 illustrated alternative embodiment, the piston 16 'has the shape of a double piston, in which at a central piston rod 36 at its upper end an upper pressure plate 37 and at its opposite lower end, a lower pressure plate 38 is arranged. At the lower pressure plate 38, a lower end face 39 is formed, on which the inner, second spring 18 is supported with its underside. At the upper pressure plate 37 is an upper end face 40, which serves to support the upper end of the outer first spring 17. Thus, while from the side of the pressure plate 37, 38, the force is introduced into the other springs 17, 18, the power is dissipated via the inner guide tube 22 ', in which only an upper lid 21' firmly inserted and rigidly connected thereto. Over an upper end face 41 of the upper lid 21 ', the second end of the inner spring 18 is supported and thus provides for an upward movement of the piston 16 for a force discharge into the inner guide tube 22' and thus in the working mass 4. In a downward movement of the piston 16 is the Force discharge from the outer spring 17 at its lower end via a lower end face 42 of a guide member 43 in the form of a fixed to the inner guide tube 22 'connected guide ring.

Also, the ramming device 1 according to the Figures 3 and 4 has on its upper mass 2 an outer guide tube 33, on the inner circumferential surface 35, both an outer circumferential surface 44 of the guide member 43 and an outer circumferential surface 45 of the upper pressure plate 37 are supported. In this way, with a large axial distance of the upper pressure plate 37 of the guide member 43, a clean coaxial guidance of the spring set 3 and the inner guide tube 22 'of the working mass 4 provided in the outer mass outer guide tube 33.

The advantage of the significantly reduced axial length of the spring set 3 over the linear sequential arrangement according to the prior art applies to the embodiment of the ramming device 1 according to the Figures 3 and 4 as well.

The difference between the embodiments described above and the ramming device according to FIGS Figures 5 and 6 consists essentially in the fact that the local spring set 3 'only consists of a single spring 17. The wire of the uppermost turn 46 of the spring 17 is guided in its end portion 47 through a bore 48 in the piston 16 "and secured by bending as well as the opposite end portion 49 of the lowermost turn 50 of the spring 17 secured in the bore The movement of the piston 16 "thus results in the downward stroke to a compression of the spring 17 and thus to transmit compressive forces on an intermediate wall 52 of the inner guide tube 22 'and thus the working mass 4. The opposite Upward movement leads analogously to the transmission of tensile forces on the working mass. While the inner guide tube 22 "and outer guide tube 33 are telescopically slid, as in the previously described alternative embodiments, the stepped piston 16" within its smaller diameter upper portion 24 "within a mating bore in an upper lid 21 "the inner guide tube 22" out. In a lower, in Diameter enlarged portion 26 "of the piston 16" slides the latter on the inner circumferential surface 53 of the inner guide tube 22 ".

In order to avoid metallic abutment of the lower portion 26 "of the piston 16" on the underside of the upper lid 21 "of the inner guide tube 26" can be used in a free space 54, a not shown damping element. In order to avoid a block stop of the spring 17 analogously, a damping element can also be placed in the inner free space 55, which in the activation case supports the piston 16 "with its underside against an upper side of the intermediate wall 52.

Due to the use of only a single spring 17 as a tension and compression spring with periodically alternating load application of the structural design effort is low and the axial length as well as in the embodiments according to the FIGS. 1 to 4 significantly reduced compared to the prior art.

LIST OF REFERENCE NUMBERS

1

tamping device

2

upper mass

3, 3 '

spring set

4

working mass

5

Foot Adapter

6

foot pipe

7

upper flange

8th

bellow

9

line

10

gear

11

crank pin

12

pleuel

13

upper eye

14

lower eye

15

piston pin

16, 16 ', 16 "

piston

17

first spring

18

second spring

19

lower end face

20

upper face

21, 21 "

upper lid

22, 22 ', 22 "

inner guide tube

23

lower lid

24, 24 "

upper section

25

paragraph

26, 26 "

lower section

27

upper damping element

28

intermediate cover

29

lower end face

30

upper face

31

top

32

second damping element

33

outer guide tube

34

outer jacket surface

35

inner jacket surface

36

piston rod

37

upper pressure plate

38

lower pressure plate

39

lower end face

40

upper face

41

upper face

42

lower end face

43

guide element

44

outer jacket surface

45

outer jacket surface

46

topmost turn

47

end

48

drilling

49

end

50

lowest turn

51

drilling

52

partition

53

inner jacket surface

54

free space

55

free space

Ü

overlap area

F

free space

Claims (12)

1. A stamping device (1) for earth compaction, having a working mass (4), which is driven in a stamping manner and can be linearly moved back and forth by a motor belonging to an upper mass (2) via a crank mechanism, a piston (16, 16') and a spring assembly (3), wherein the spring assembly has at least one first spring (17), which can be compressed during a forth movement of the piston (16, 16'), and at least one second spring (18), which can be compressed during a back movement of the piston (16, 16'), characterised in that the at least one second spring (18) is arranged inside a free space (F) in the interior of the at least one first spring (17).
2. The stamping device according to Claim 1, characterised in that all springs (17, 18) are coil springs, which are arranged coaxially to one another, wherein an external diameter of the at least one first spring (17) is larger than the internal diameter of the at least one second spring (18).
3. The stamping device according to Claim 1 or 2, characterised in that the piston (16) has a pot shape, has two end faces (19, 30), which point away from one another, for supporting the at least one first spring (17) and the at least one second spring (18), and is arranged in an overlap region (Ü) of the springs (17, 18) between the at least one first spring (17) and the at least one second spring (18).
4. The stamping device according to Claim 3, characterised in that the piston (16) has an upper tubular section (24) and a lower tubular section (26), wherein the lower section (26) has a larger diameter compared to the upper section (24).
5. The stamping device according to Claim 3 or 4, characterised in that the upper mass (2) has an outer guide tube (33), in which an inner guide tube (22) of the working mass (4) can be moved back and forth, wherein an outer enveloping surface (34) of the inner guide tube (22) is in sliding contact with an inner enveloping surface (35) of the outer guide tube (33), wherein the inner guide tube (22) preferably has two end faces (20, 29), which are arranged at a distance from one another and face one another, on which end faces the at least one first spring (17) and the at least one second spring (18) are supported by means of the drive-side ends thereof in each case.
6. The stamping device according to Claim 5, characterised in that the first spring (17) is arranged inside a space delimited by an inner enveloping surface of the inner guide tube (22) and an outer enveloping surface of the piston (16), and the second spring (18) is arranged inside a tubular end section of the piston (16).
7. The stamping device according to Claim 1 or 2, characterised in that the piston (16') has two pressure elements, particularly pressure plates (37, 38), which are spaced apart from one another and coupled to one another via a piston rod (36) and which have two end faces (39, 40), which face one another, for supporting the at least one first spring (17) and the at least one second spring (18), and the piston is arranged in an overlap region (Ü) of the springs (17, 18) inside a free space (F) in the innermost spring (18).
8. The stamping device according to Claim 7, characterised in that the upper mass (2) has an outer guide tube (33), in which an inner guide tube (22') of the working mass (4) can be moved back and forth, wherein an inner enveloping surface (35) of the outer guide tube (33) is in sliding contact both with an outer enveloping surface (45) of the piston (16'), particularly the pressure plate (37) thereof, which faces the upper mass (2), and with an outer enveloping surface (44) of a guide element (43) protruding radially outwards above an outer enveloping surface (34) of the inner guide tube (22'), particularly in the form of a guide ring, wherein the inner guide tube (22') has a first end face, which is arranged in the interior thereof, for the at least one first spring (17) and a second end face, which protrudes radially outwards above the outer enveloping surface thereof, for the at least one second spring (18), wherein the second end face is formed by the guide element (43), particularly the guide ring.
9. A stamping device (1) for earth compaction, having a working mass (4), which is driven in a stamping manner and can be linearly moved back and forth by a motor belonging to an upper mass (2) via a crank mechanism, a piston (16") and a spring assembly (3"), wherein the spring assembly (3") transmits a force to the working mass (4) both during the forth movement and during the back movement, characterised in that all springs (17) in the spring assembly (3") transmit pressing forces during the forth movement of the piston (16") and pulling forces during the back movement of the piston (16") to the working mass (4).
10. The stamping device according to Claim 9, characterised in that the spring assembly (3") consists of a single spring (17), which is preferably realised as a coil spring.
11. The stamping device according to Claim 9 or 10, characterised in that all of the springs (17) are coil springs and engage in each case at an end facing the upper mass (2) by means of an end section (47) of the wire thereof in a secured manner into a hole (48) in the piston (16") and engage in each case at an end facing the working mass (4) by means of an end section (49) of the wire thereof in a secured manner into a hole (51) in an inner guide tube (22") of the working mass (4), wherein an outer enveloping surface (34) of the inner guide tube (22") is in axially sliding contact with an inner enveloping surface (35) of the outer guide tube (33) of the upper mass (2).
12. The stamping device according to Claim 11, characterised in that a first damping element is arranged between a first end face of the piston (16") and a first end face of the inner guide tube (22"), which damping element radially externally surrounds a section of the piston (16") facing the upper mass (2), and in that a second damping element is arranged between a second end face of the piston (16") and a second end face of the inner guide tube (22"), which damping element is located in the interior of the spring assembly (3"), particularly in the interior of the single spring (17), particularly in the form of a coil spring.

Images