DE102011100632A1 - Piston-cylinder unit for drive system of telescopic boom, has cylinder and piston movable in cylinder, where piston divides interior of cylinder in cylinder spaces - Google Patents

Abstract

The piston-cylinder unit (8) has a cylinder and a piston movable in cylinder, where the piston divides the interior of the cylinder in cylinder spaces. A wire is contained within a piston rod (18) to communicate with the former cylinder space. Another wire is contained within the piston rod to communicate with the latter cylinder space as a function of the position of the piston. An independent claim is also included for a drive system with a float valve.

Description

The present invention relates to a piston-cylinder unit and a drive system for a telescopic boom, which contains at least one of the piston-cylinder units according to the invention.

Telescopic booms, also called telescopic booms, are equipped with different drive systems depending on market requirements. These range from the low-lift and long-reach platform to the application as a weight-optimized boom system for the overhead crane to the technology-leading design as an all-terrain vehicle crane. The design of the boom systems is largely based on the use of hydraulic actuators. A distinction is made between drive systems with rope mechanics without locking and systems with locking bolts. For short range systems, telescopic cylinders with and without cable mechanics are used. For larger telescopic cranes, a single-cylinder telescopic system has been developed, which performs the thrust piece movement by means of locking bolts and detachable drive cylinder. When mobile Aufbauladekran is the demand of a compact storage position during transport in the foreground, the moving pushers are usually each driven by its own hydraulic cylinder.

In multi-part telescopic arms of the type mentioned, it is often desirable that the individual thrust pieces in a predetermined order and / or extend. For this is in the European patent specification EP 0 566 720 B1 already a multi-stage telescopic boom has been presented.

It is the object of the present invention to provide a robust and reliable piston-cylinder unit which can be used for a drive system of a telescopic boom. Also, a corresponding drive system is the subject of the present invention.

This object is achieved by the piston-cylinder unit according to claim 1 or by the drive system according to claim 5. The dependent subclaims advantageous developments are determined.

The piston-cylinder unit according to the invention consists of a cylinder and a piston which can move therein. The piston divides the interior of the cylinder into two cylinder chambers, namely a first, which is located between the piston and cylinder head and a second, which is located between the piston and the cylinder bottom. Also attached to the piston is a piston rod which moves together with the piston and, depending on the piston position, projects at least partially outside the cylinder. In this piston rod according to the invention are three lines, namely a first communicating with the first cylinder chamber, a second, which communicates with the second cylinder chamber depending on the piston position and a third line into which an inner tube protrudes depending on the piston position. This inner tube is preferably firmly connected to the cylinder, for example in the region of the cylinder bottom. Under communicating is to be understood here, the liquid, such as hydraulic oil, gas and / or the like can be replaced. The three lines of the piston rod, the inner tube and also the second cylinder chamber can be connected via associated connections with lines through which liquid, gas and / or the like can be supplied and removed. As a result, in particular both corresponding pressure sources as well as upstream and downstream piston-cylinder units can be connected.

Although the invention is described below using the example of a hydraulic system, it is by no means limited thereto. Instead of a hydraulic system, a pneumatic, a hydro-pneumatic system or the like is possible.

In a further development, a valve is arranged, which then connects the second cylinder chamber with the second line within the piston rod when the piston is almost extended. As a result, hydraulic fluid which is supplied to drive the piston can be forwarded only at the corresponding piston position, for example, to control a subsequent piston-cylinder unit.

It is also advantageous if a further valve is present, which then connects the first cylinder chamber with a connected line when the piston is almost retracted. This has particular advantages when retracting the piston-cylinder system. Because this allows a selected piston-cylinder unit to be controlled such that initially only this enters. Only when this has been done to the desired extent, hydraulic fluid is passed to another piston-cylinder unit, so that they can retract.

A drive system for a telescopic boom or the like, which uses at least one of the piston-cylinder units according to the invention, has the advantages already described. Such a system can be further improved if a rapid traverse valve is provided. This is based in particular on the recognition that this can compensate for disadvantages resulting from the larger volume on the market Bottom side of the cylinder compared to the ring side. As a result, approximately the same speeds can be achieved depending on the load situation during extension.

Further details and advantages of the present invention will be explained below with reference to preferred embodiments. Show

1 A piston-cylinder unit in plan view

2 The piston-cylinder unit in a sectional view

3 Details of the center of the piston-cylinder unit in a sectional view

4 Details of the bottom of the piston-cylinder unit in a sectional view

5 Details of the head of the piston-cylinder unit in a sectional view

6 Sequence control Extension of a drive system for a telescopic boom

7 Sequence control Retracting a drive system for a telescopic boom

8th Circuit diagram of a rapid traverse valve.

1 shows in plan view a piston-cylinder unit 8th , which for the purposes of the following description is subdivided into a header area 10 , a middle area 12 and a floor area 14 , Out 1 are in particular the exterior of a cylinder 16 and a part of a piston rod 18 recognizable, as far as these from the cylinder 16 protrudes. Furthermore, it can be seen that the bottom of the cylinder 16 a first line connection 20 and a second conduit connection 22 contains. At the end of the piston rod 18 are further line connections 24 . 26 . 28 available. Directional terms used below - such as right, left, top, bottom - refer to the respective figures unless otherwise specified.

2 shows a sectional view of the piston-cylinder unit 8th along the line AA 1 , In particular, a piston can be seen 30 as well as an inner tube 32 at one end with the pipe connection 22 connected and into the interior of the piston rod 18 is guided, where at the other end of the inner tube 32 a sealing head 34 located. On the outside of the cylinder 16 is a first 2/2-way valve 36 arranged. A second 2/2-way valve 38 is inside the cylinder 16 available.

3 shows sectional details of the middle area 12 the piston-cylinder unit 8th , The cylinder 16 includes a cylinder tube 40 at the left end with a ring seal carrier 42 connected is. At this is an O-ring 44 as well as guide bands 46 . 48 . 50 , a rod seal 52 and a scraper ring 54 arranged. The piston rod 18 includes a first piston rod tube 56 , inside which the inner tube 32 is movably guided. To the first piston rod tube 56 there is a second piston rod tube 58 , creating a first piston rod annulus 60 is formed. To the second piston rod tube 58 There is also a third piston rod tube 62 , creating a second piston rod annulus 64 is formed. Around the inner tube 32 within the first piston rod tube 56 simply to be able to move back and forth are at the sealing head 34 guide rings 66 . 68 arranged. The inner tube 32 is preferably dimensioned such that it is also when the piston is extended 30 still in the pipe 56 protrudes.

Outside the cylinder tube 40 is the 2/2-way valve 36 by means of a flange plate 70 arranged in an o-ring 72 is stored. The valve 36 contains a ring valve block 74 at which a pushrod bearing 76 is attached, in which is a pestle 78 that can move from a scraper ring 80 and an O-ring 82 surrounded by a ring. Inside the ring valve block 74 are also a control piston 84 and a compression spring 86 arranged. The valve 36 also by means of a screw plug 88 closed by an O-ring 90 is sealed.

4 shows in sectional view details of the cylinder bottom 14 the piston-cylinder unit 8th , The cylinder 16 is right through a cap 92 limited, in by means of an adapter 94 the pipe connection 22 is mounted. A copper ring 96 serves for sealing. Between the piston bottom 98 - here on the right side of the piston 30 - and the cap 92 there is a floor space 99 , the over the line connection 20 can be connected to the outside. Left of the piston 30 are the valve 38 as well as the piston rod 18 - consisting essentially of the pipes 56 . 58 . 62 - arranged. The valve 38 contains a compression spring 102 , a control piston cooperating therewith 104 that with an inner pestle 106 connected is. This is movably stored in a connector 108 , In the area of the valve 38 In addition, some guiding and sealing means are present, such as a guide ring 110 and a copper ring 112 , On the lower side of the piston-cylinder unit 8th are in 4 a circlip 110 , a stopper disc 112 , a compression spring 114 , a rolling element 116 , a housing carrier 118 as well as a guide ring 120 and o-rings 122 . 124 . 126 shown. Links the Piston assembly is an annulus 33 , which extends to the right end of the ring seal carrier 42 (please refer 3 ) and with the annulus 64 communicates (not shown here), so that liquids can pass from one room to another accordingly.

5 shows in section details of the cylinder head 10 the piston-cylinder unit 8th , There is a piston rod head 128 present, the left ends of the pipes 56 . 58 . 62 and to the moreover the line connections 24 . 26 . 28 - The latter not shown here - are attached in such a way that on the line connection 24 the inside of the pipe 56 , via the line connection 26 the annulus 64 and over the line connection 28 the annulus 60 can be connected to the outside. For sealing the piston rod end 128 opposite the pipes 56 . 58 and 62 are also O-rings 130 . 132 respectively. 134 intended.

As in particular in 2 . 3 . 4 is recognizable form the annular spaces 60 . 64 inside the piston rod 18 Lines, the associated connections between the terminals 26 . 28 on the one hand and the interior of the cylinder on the other. Corresponding lines within the piston rod can be made to different, such as through holes, pipes or the like.

In 6 . 7 In each case a drive system for a telescopic boom is shown, the four piston-cylinder units 8a . 8b . 8c . 8d contains, which is essentially the piston-cylinder unit 8th correspond, as described with reference to the previous figures. In addition, means are shown, which allow to control this boom. In 6 is a sequential extension and in 7 a sequencing retraction is shown.

In 6 is a 4/3 normal way valve 135 shown connected to a pressure source P and to a tank T. The pressure source P provides hydraulic oil - or any other suitable liquid - with appropriate pressure, so that the piston-cylinder units 8th can be controlled. The tank T receives hydraulic oil, which is located in individual rooms of the piston-cylinder units 8th and associated lines and is pushed out with appropriate control. The valve 135 is switched to extend such that the pressure source P with a supply line 136a Connected via a check valve 138 to the line connection 20a leads, leaving hydraulic oil in the floor space 99a the first piston-cylinder unit 8a can be directed. The administration 136a is over another line 140 also to the control input of a first load-holding valve 142 connected, which can open at the appropriate oil pressure and an oil return via a line 144 allows to the tank T.

At the piston-cylinder units 8b - 8d are also valves 36b - 36d arranged as in 2 . 3 shown. The associated plunger 78 become by stops 146b - 146d pushed in when the cylinders 30 retracted. When extending the cylinder 30 remove the stops 146 from the pestles 78 , For retracted rams 78 are the valves 36 switched such that a connection between entry lines 148b . 148c respectively. 148d on the one hand and the annular spaces 33b . 33c respectively. 33d on the other hand. Furthermore, return lines 150a - 150d present, over the connections 22 with the respective inner tubes 32a - 32d are connected.

Through the through the supply line 136a as well as through the line connection 20a flowing hydraulic oil becomes the piston 30a the first piston-cylinder unit 8a together with the valve 38a moves and drives to the stop. Such a movement is loud 6 to the right; as shown in previous figures, such movement would be the piston 30 move to the left. This is the ram 78 against the ring seal carrier 42 (see also 2 ) and opens the valve 38a , Only by this opening can hydraulic oil from the floor space 99a in the annulus 60a flow and from there via the line connection 28a as well as via another supply line 136b in the floor space 99b the second piston-cylinder unit 8b , Then the piston moves 30b until the stop and the valve 38b will be opened. This allows hydraulic oil through a third supply line 136c in the floor space 99c the third piston-cylinder unit 8c reach. After the piston 30c has gone to the stop, valve is 38c opened and hydraulic oil flows accordingly in the floor space 99d the fourth piston-cylinder unit 8d , This is according to 6 not fully extended, leaving both the floor space 99d as well as the annulus 33d are clearly recognizable. Because the piston-cylinder unit 8d the last in the boom shown here is and thus no hydraulic oil needs to flow into other piston-cylinder units, in the preferred embodiment, for cost reasons, no valve 38d intended. However, such a valve may nevertheless be provided, for example around the unit 8d To use as flexible as possible and, where appropriate, to install another piston-cylinder unit.

In the usual operation of in 6 shown boom is constantly more or less much hydraulic oil in the annuli 33a - 33d and associated lines. This oil is displaced when extending the pistons 30 and must therefore be derived accordingly. This happens here as follows. First, everyone piston 30 retracted. When moving the piston 30a to the right this will be in the annulus 33a located hydraulic oil in the annulus 64a pressed and from there via the entrance line 148b in the annulus 33b , It should be noted that the piston 30b at this time still retracted and the valve 36b is open. Furthermore, the pushed-out hydraulic oil passes through the entry line 148c , the annulus 33c , the approach line 148d and the annulus 33d in the annulus 64d , This is over a bridge line 152 with the inner tube 32d connected, so that expelled hydraulic oil through the return line 150d , the inner tube 32c , the return line 150c , the inner tube 32b , the return line 150b , the inner tube 32a , the return line 150a , The administration 144 and the valve 142 back into the tank T can flow. Similar processes happen when successively the pistons 30b . 30c respectively. 30d exit.

7 shows the same boom as in 6 However, this is switched here so that the sequence control retraction is possible. The valve 135 is switched such that the pressure source P via a second check valve 139 with the return line 150a connected is. This hydraulic oil passes through the inner tube 32a , The administration 150b , the inner tube 32b , The administration 150c , the inner tube 32c , The administration 150d , the inner tube 32d in the pipe 56d and over the bridge line 152 in the annulus 64d and therefore also in the annulus 33d , Thus, the piston 30d moved to the left until the stop 146d the pestle 78 of the valve 36d pushes in and thus the valve 36d opens. Only then does hydraulic oil pass over the entry line 148d and the annulus 64c in the annulus 33c , This will cause the piston 30c moved to the left and then the valve 36c open. This can cause the piston 30b be moved to the left and then in an analogous manner, the piston 30a , In 7 is the piston-cylinder unit 8a shown such that the piston 30a not yet completely retracted. As a result, both spaces 33a and 99a good to see.

Even when driving in, hydraulic oil must be displaced - from the floor space 99 and the associated lines. This oil flows over the pipe 136d , the annulus 60c , The administration 136c , the annulus 60b , The administration 136b , the annulus 60a , a second load-holding valve 143 to the tank T.

The embodiment described thus makes it possible for both the extension and the retraction to take place in a predetermined sequence. If initially all pistons 30 are retracted, are all valves 36 opened and all valves 38 closed. Thus, when extending hydraulic fluid initially so only causes pressure on the piston 30a until the valve 38a is opened. Only then does hydraulic oil enter the floor space 99b , causing pistons 30b moving, etc. When retracting, the piston-cylinder units 8th controlled in reverse order. For those who are fully extended, the valve is 38 opened and the valve 36 closed. When partially extended piston are both valves in the respective piston-cylinder unit 36 . 38 closed. Suppose the piston-cylinder units 8a . 8b are fully extended, the unit 8c only partially and the unit 8d is fully retracted. Then you are at 8a and 8b the valves 38a . 38b open and at 8c and 8d are the valves 38c . 38d closed. Furthermore, in such a case, the valves 36b . 36c closed and valve 36d it is open. Therefore causes the following position retraction in such a case that hydraulic oil first on all inner tubes 32 as well as the communicating piston rod tubes 56 to the bridge line 152 arrives. The hydraulic oil or the pressure caused by this can then across the room 64d , the open valve 36d , The administration 148d in the annulus 33c arrive and the piston 30c set in motion. There valve 36c (yet) closed, however, the inflowing hydraulic oil exerts no force on the pistons 30b . 30a out. Only when the piston 30c is fully retracted, opens valve 36c , so that then piston 30b can be moved. Only when this is fully retracted, will valve 36b opened and piston 30a emotional.

The valves 142 . 143 serve in particular to slow down initiated movements and in the operation of the boom, the load on the piston 30 to keep. For such operation additionally the valve 135 controlled accordingly.

In the preferred embodiment, the piston-cylinder unit 8a without a valve 36 fitted. This is basically not necessary, because unity 8a the last one is entering. For reasons of flexibility, however, it is also possible with unit 8a a valve 36 with associated stop 146 provided.

To optimize the extension and retraction, it is advantageous at the points B, C (see 6 ) interpose a rapid traverse valve. A corresponding circuit diagram is in 8th shown. Thereby, the disadvantage can be compensated, due to the larger volume on the bottom side of the cylinder 30 , compared to the ring side exists. In addition, approximately the same speeds can be achieved in the extension and retraction.

• – Das Ventil 36 kann derart gestaltet und angeordnet werden, dass es sich zumindest teilweise innerhalb des Zylinders, beispielsweise im Bereich des Zylinderkopfes, des Zylinderbodens und/oder der Zylindermitte, befindet.
• – Die Ventile 36, 38 können derart gestaltet und angeordnet werden, dass sie nicht nur dann schalten, wenn der Kolben 30 nahezu vollständig ein- bzw. ausgefahren ist, sondern bei einer vorgegebenen Kolbenposition.

It is understood that the described embodiments can be modified and combined in many ways. For example, the following is possible:

• - The valve 36 can be designed and arranged so that it is at least partially within the cylinder, for example in the region of the cylinder head, the cylinder bottom and / or the cylinder center is located.
• - The valves 36 . 38 can be designed and arranged so that they not only switch when the piston 30 almost completely retracted or extended, but at a given piston position.

LIST OF REFERENCE NUMBERS

8th

Piston-cylinder unit

10

Head area of the piston-cylinder unit

12

Middle region of the piston-cylinder unit

14

Ground area of the piston-cylinder unit

16

cylinder

18

piston rod

20

First pipe connection to cylinder bottom

22

Second pipe connection to cylinder bottom

24

First pipe connection to piston rod

26

Second pipe connection to piston rod

28

Third line connection to piston rod

30

piston

32

inner tube

33

Annulus (at piston top)

34

sealing head

36

First 2/2-way valve (outside the cylinder)

38

Second 2/2-way valve (inside the cylinder)

40

cylinder tube

42

Ring seal carrier

44

O-ring

46

guide band

48

guide band

50

guide band

52

rod seal

54

scraper

56

First piston rod tube (in which inner tube 32 emotional)

58

Second piston rod tube

60

First piston rod annulus (between the tubes 56 . 58 )

62

Third piston rod tube

64

Second piston rod annulus (between the tubes 58 . 62 )

66

guide ring

68

guide ring

70

flange

72

O-ring

74

Ring valve block

76

follower bearings

78

tappet

80

scraper

82

O-ring

84

spool

86

compression spring

88

Screw

90

O-ring

92

cap

94

adapter

96

copper ring

98

Piston bottom

99

Floor space (at the bottom of the piston)

102

compression spring

104

spool

106

interior follower

108

joint

110

circlip

112

stop disc

114

compression spring

116

rolling elements

118

housing support

120

guide ring

122

O-ring

124

O-ring

126

O-ring

128

Piston rod head

130

O-ring

132

O-ring

134

O-ring

135

4/3-way valve Normal

136

supply

138

First check valve

139

Second check valve

140

management

142

First load-holding valve

143

Second load-holding valve

144

management

146

attacks

148

Einfahrleitungen

150

Return lines

152

bridge line

A-A

Cutting line ( 1 )

B, C

Points for rapid-action valve ( 6 )

P

pressure source

T

tank

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0566720 B1 [0003]

Claims (6)

Piston-cylinder unit ( 8th ) with a cylinder ( 40 ) and a piston movable therein ( 30 ), the inside of the cylinder ( 40 ) divided into a first cylinder space ( 33 ) and a second cylinder space ( 99 ), wherein on a first side of the piston ( 30 ) a piston rod ( 18 ) is arranged, which depends on the position of the piston ( 30 ) at least partially outside the cylinder ( 40 ), characterized in that inside the piston rod ( 18 ) - a first line ( 64 ), which is connected to the first cylinder space ( 33 ) communicates, - a second line ( 60 ), which depends on the position of the piston ( 30 ) with the second cylinder space ( 99 ) communicates and - a third line ( 56 ), in which, depending on the position of the piston ( 30 ) an inner tube ( 32 ) protrudes that neither with the first cylinder chamber ( 33 ) still with the second cylinder space ( 99 ) communicates. Piston-cylinder unit ( 8th ) according to claim 1, characterized in that a first valve ( 38 ) inside and / or outside the cylinder ( 40 ) is arranged such that it the second line ( 60 ) with the piston almost fully extended ( 30 ) with the second cylinder space ( 99 ) connects. Piston-cylinder unit ( 8th ) according to one of the preceding claims, characterized in that a second valve ( 36 ) within, such as in the area of the cylinder head ( 10 ) or in the area of the cylinder bottom ( 14 ), and / or outside the cylinder ( 40 ) is arranged such that it has a connecting line ( 148 ) with almost retracted cylinder ( 30 ) with the first cylinder space ( 33 ) connects. Piston-cylinder unit ( 8th ) according to one of the preceding claims, characterized in that the first valve ( 38 ) and / or the second valve ( 36 ) are designed as a 2/2-way valve. Drive system for a telescopic boom with at least one of the piston-cylinder units ( 8th ) according to one of the preceding claims. Drive system according to claim 5, characterized in that between an inflow line ( 136 ) and a return line ( 150 ) a rapid traverse valve is arranged.

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