EP1864024B1 - Lockable working cylinder - Google Patents

Abstract

A lockable working cylinder comprising a housing and a piston that can be displaced in a primary pressure chamber of the housing. A piston rod tube leads from the piston out of the pressure chamber and a spindle rotates in the piston or piston rod tube, the spindle being allocated to a unit that halts the rotational displacement. The spindle or a rotational sleeve that is placed over the spindle has a radial pressure chamber, in which a locking bolt engages, said bolt being introduced radially.

Description

The invention relates to a lockable power cylinder having a housing and a piston movable therein in a main pressure chamber, from which a piston rod tube leads from the main pressure chamber, wherein in the piston or the piston rod tube rotates a spindle, which is associated with a means for stopping the rotational movement, wherein the spindle or one of these mounted rotary sleeve has a radially disposed space in which a radially feasible locking pin engages.

State of the art

Such cylinders are known in a variety of forms and designs and on the market. For example, in the DE 41 41 460 C2 a fluid operated cylinder shown in which a rotatable spindle engages a piston rod tube. If the corresponding piston, the Assigned to the piston rod tube, the spindle also rotates, so that the piston rod tube can move axially.

In all these working cylinders, the problem arises that, should the pressure in the actual main pressure chamber in which the piston is pressurized collapse, for example, by breaking the sealing collar, the piston under the pressure of the load or even under a train on its own Movement is set, the spindle runs with its external thread, the internal thread of the piston rod tube.

In order to prevent this independent movement of the piston rod, corresponding brake or locking units are provided. For example, in the DE 297 20 838 U1 proposed a braking surface which presses against a brake cone, so that thereby the spindle rotation is decelerated. Such a braking device is not suitable for braking larger loads acting on the working cylinder. Furthermore, as a result, the spindle rotation can not be stopped abruptly.

Also from the DE 202 16 197 a locking unit is known, which forms a functionally reliable, fine-step and reliably lockable component arrangement. In this case, a rotational movement of the threaded spindle by means of an axially displaceable connecting member and a rotationally fixed counter-member braking locking unit is provided, wherein the held by a compression spring in the connecting position connecting member can be unlocked by a displaceable against the spring action thrust body. The connecting member is formed as a with the compression spring on a Tragansatzteil the threaded spindle axially displaceable locking piston, at its front end of the cylinder bottom directed end face an annular extending and engageable on a bottom-side counter toothing tooth profile is provided. Coaxially with this, the locking piston which can be displaced on the carrying attachment part is rotatably matched to the pushing body by means of a central supporting bearing. This lock is problematic because on the one hand a front-side locking can be worn down over time. On the other hand, the cohesion of the frontal toothing is dependent on the pressure medium, which, for example, when leaks occur, can easily fail.

A working cylinder of the above type is from the EP 1 106 841 A2 known. There, the spindle has radially arranged spaces into which engages a radially feasible locking pin. The actuation of the locking pin via a, the locking pin bottom integrally formed piston, which is feasible in a pressure chamber against the force of a spring.

task

Object of the present invention is to provide a working cylinder of the type mentioned above, in which when you release the pressure in the main pressure chamber, there is a very rapid and secure locking of the piston or the piston rod tube or the spindle.

Solution of the task

To achieve the object leads that in the space in front of the locking pin, a pressure medium can be introduced and thus the space is designed as a pressure chamber.

This radially feasible locking bolt ensures that, as long as it enters the pressure chamber, a secure locking of the spindle takes place. As a result, the piston and the piston rod tube is set. Another rotational movement is only possible when the locking pin is removed from its rest position.

If in the following is spoken only by spindle, this also includes a mounted on the spindle rotary sleeve, which serves to better mounting and storage of the spindle.

For the movement of the locking pin in and out of locking position of the pressure chamber is under the pressure of a pressure medium, which presses the locking pin from the pressure chamber. As a result, the spindle is free and can rotate.

On the other hand, the pressure chamber could be associated with the locking bolt, a force storage device, such as a coil spring. If the pressure in the pressure chamber is removed in this case, the locking pin can retract under the pressure of the compression spring in this pressure chamber and lock the spindle.

It is also conceivable to put together with a coil spring or without the coil spring the locking pin on the other hand, the pressure chamber under the pressure of a hydraulic or pneumatic medium, so that controlled by a corresponding electronic control, built pressure and the locking pin can be moved in the pressure chamber. Here are many possibilities conceivable and should be encompassed by the invention.

However, it is preferred that a cup-shaped locking pressure chamber is set up around the spindle end, from which then the pressure chamber, which receives the locking pin, branches off. From this cup-shaped locking pressure chamber enters a pressure medium in the pressure chamber, since there the locking pin is performed with play. If the bottom of the room is funnel-shaped, so the pressure medium can pass in front of the locking pin and push it out of the pressure chamber. The funnel-shaped training does not have to be.

Above all, the latter arrangement is desirable when a plurality of pressure chambers radially distributed around the spindle or, the spindle end are provided. This radial distribution causes the locking pin to have a variety of desired capabilities to retract into the next compression space. As a result, the unwanted rotation of the spindle, which follows, for example, a leak in the system is reduced to a minimum.

It is even better if more than one locking pin is provided, since then the determination of the spindle is stabilized. Further, it is possible to design the distance between two locking pins unequal to the distance between two pressure chambers, so that the pitch for the locking is further reduced.

This means that the rotation of the spindle is reduced to a minimum.

On the spindle or the above-mentioned rotating sleeve, an annular collar should preferably be provided, which is supported against at least one needle bearing. This needle bearing absorbs the forces acting axially, preferably a Spindelendfläche still maintains a slight distance from a blind hole bottom of a blind hole around them.

In a preferred embodiment, the entire pressure medium system is coupled together. This means above all that the pressure medium supply is coupled to the movement of the actual piston with the pressure medium supply to the above-mentioned locking pressure chamber for the locking pin. The pressure medium supply to the locking pressure chamber and the main pressure chamber is controlled, however. It is important that the locking pressure chamber is separated from the main pressure chamber by a corresponding seal. The pressure medium supply to the main pressure chamber is designed so that only the pressure medium supply to the locking pressure chamber reaches a predetermined value, for example from 15 to 25 bar, which is sufficient that the locking pin is pushed out of the pressure chamber before the piston is pressurized in the main pressure chamber , This means that the spindle is first released before it is moved axially in the working cylinder. Thus, the locking pin takes over a second mechanical backup, while the first backup is done hydraulically by at least one load-holding valve. This load-holding valve is arranged in the pressure medium system so that it can hold a force acting on the piston rod or the piston force as soon as the pressure medium supply, for example, the hydraulic unit, is turned off. Only when this first backup stops working, for example, in the case of a faulty load-holding valve or leakage in the system, the second, mechanical fuse enters into force, since in this case the spindle rotates and the locking pin under the pressure of him supporting coil spring in the pressure chamber retracts.

The present working cylinder is intended primarily for heavy load. The scope is extremely diverse. He goes from, for example, double-deck car transporters, in which individual floors are supported against each other, up to hydraulic presses or devices for the position of formwork in construction. These are only a few application examples, the invention is of course not limited thereto.

figure description

• Figur 1 eine Draufsicht auf einen erfindungsgemässen Arbeitszylinder;
• Figur 2 eine Frontansicht des Arbeitszylinders gemäss Figur 1;
• Figur 3 einen Querschnitt durch den Arbeitszylinder gemäss Linie III - III in Figur 2.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing; this shows in

• FIG. 1 a plan view of an inventive cylinder;
• FIG. 2 a front view of the working cylinder according to FIG. 1 ;
• FIG. 3 a cross section through the working cylinder according to line III - III in FIG. 2 ,

An inventive working cylinder P has according to FIG. 1 a housing 1, on which a distribution block 2 is placed for print media. On the right side of the housing 1 is a tab 3 with an eye 4 for mounting in a hook not shown in detail od. The like. Formed. The eye 4 is seated in a rotary ring 5, which forms an annular space 6 towards the tab 3, which can be filled with a lubricant via a lubricant 7.

To the tab 3 includes a lower housing part 8, to which a middle part 9 is pushed. This in turn goes into a cylinder tube 10, in the opening 11, a guide sleeve 12 is inserted. The guide sleeve 12 encloses a piston rod tube 13, which is screwed into a piston 14. The piston 14 is guided in the interior of the cylinder tube 10 and is supported against this cylinder tube 10 by means of a sealing ring 15.

In an open end of the piston rod tube 13 a threaded piece 16 is screwed, which in one piece in a further tab 17 with a Connection eye 18 for example, a load or snap hook transitions.

The piston rod tube 13 is at least for the most part provided with an internal thread not shown in detail, in which a spindle 20 rotates with a corresponding external thread. This spindle 20 also passes through the piston 14 and sits with a spindle root 21 in a rotary sleeve 22, which is received by the middle part 9 and the lower housing part 8. For this purpose, the lower housing part 8 forms a blind hole 23, in which the rotary sleeve 22 is received at a distance. The rotary sleeve 22 holds with an end face 24 of a blind hole bottom 25 a slight distance.

Further, the rotary sleeve 22 engages with an annular collar 26 in an annular space 27, which is formed between the middle part 9 and the lower housing part 8. In this annular space 27, the annular collar 26 is supported on both sides in each case via a needle bearing 29 or 30 against corresponding shoulder or end surfaces formed by the housing parts.

In the rotary sleeve 22 near the end face 24 at least two pressure chambers 31.1 and 31.2 are formed, which are each provided with a funnel-shaped bottom 32. In the pressure chamber 31.1 sits a locking pin 33, which is acted upon by a coil spring 34 on the other hand.

Since the rotary sleeve 22 maintains a slight distance from the blind hole 23 and also the end face 24 to the blind hole bottom 25, these spaces together form a cup-shaped locking pressure chamber 38. This locking pressure chamber 38 is connected by a ring seal 40, which after the needle bearing 29 between rotary sleeve 22 and Housing middle part 9 is arranged, separated from the main pressure chamber 36.

The operation of the inventive working cylinder is the following:

Via a pressure line not shown in detail, pressure medium is supplied through the distributor block 2 to the locking pressure chamber 38. Since the locking pin 33 is guided in the pressure chamber 31.1 with play, this pressure medium passes in front of the locking pin 33 in the hopper bottom 23 and pushes the locking pin 33 against the force of the coil spring 34 from the pressure chamber 31.1. Thereby, the rotary sleeve 22 can rotate freely in the blind hole 23, wherein the rotation is supported by the needle bearings 29 and 30.

Once the pressure in the locking chamber 38 has reached a certain value, for example 20 bar, which ensures that the locking pin 33 is pressed out of the pressure chamber 31.1, pressure medium also passes behind the piston 14. This is moved to the left, so a Pressure chamber 36 is reduced in front of the piston 14. The volume of pressure medium from this pressure chamber 36 passes through a return line 37 back to, for example, a pressure medium reservoir.

A pitch of the internal thread, not shown, in the piston rod tube 13 and the external thread, not shown, on the spindle 20 is selected such that upon displacement of the piston rod tube 13 under the pressure of the piston 14 to the left, the spindle 20 is set in rotary motion.

During the supply of pressure medium behind the piston 14, the hydraulic system is controlled so that there is always in the locking pressure chamber 38 by 15 to 25 bar higher pressure, as in the main pressure chamber 36. This ensures that the locking pin 33 remains in its pushed-back position ,

Now has the piston rod tube 13 reaches its desired end position, the hydraulic unit promotes no further pressure medium, neither to the main pressure chamber 36 nor to the locking pressure chamber 38. This means that both pressure chambers are depressurized. From the pressure chamber behind the piston 14, however, no pressure medium can flow back, as this by a Load holding valve 35 is prevented. This load-holding valve is the first safety device of the lockable working cylinder according to the invention. The second fuse is taken over by the locking pin 33. This is because the locking pressure chamber 38 is depressurized, the circumference of the rotary sleeve 22 at.

If, for whatever reason, a rotation of the spindle 20 take place, for example as a result of leakage of the main pressure chamber 36 or malfunction of the load-holding valve 35, the locking pin 33, which is pressed radially against the rotary sleeve 22 under the pressure of the coil spring 34 in a corresponding pressure chamber 31.1 and 31.2 pressed as soon as the rotation of the rotary sleeve 22 rotates this pressure chamber 31.1 in the region of the locking pin 33. As a result, a further rotation of the spindle 20 is prevented, so that the piston rod tube 13 must remain in its position. A solution of this lock can only be made again when pressure fluid flows into the locking pressure chamber 38 and the locking pin 33 is pushed out of its detent position in the pressure chamber 31.1.

LIST OF REFERENCE NUMBERS

1 casing 34 coil spring 67 2 distribution block 35 Load-holding valve 68 3 flap 36 pressure chamber 69 4 eye 37 Return line 70 5 rotating ring 38 Locking pressure chamber 71 6 annulus 39 Pressure fluid supply line 72 7 lubricant 40 ring seal 73 8th Lower housing part 41 74 9 Housing body 42 75 10 cylinder tube 43 76 11 opening 44 77 12 guide sleeve 45 78 13 Piston rod tube 46 79 14 piston 47 15 poetry 48 16 threaded piece 49 17 flap 50 18 eye 51 19 52 20 spindle 53 21 spindle foot 54 22 rotating sleeve 55 23 blind 56 P working cylinder 24 face 57 25 Blind floor 58 26 gorget 59 27 annulus 60 28 61 29 needle roller bearings 62 30 needle roller bearings 63 31 pressure chamber 64 32 hopper bottom 65 33 locking pin 66

Claims (17)

1. Lockable working cylinder having a housing (1) and having a piston (14), which is movable therein in a main pressure space (36) and from which a piston rod tube (13) extends out of the main pressure space (36), wherein rotating in the piston (14) and/or the piston rod tube (13) is a spindle (20), with which a device for stopping the rotational movement is associated, wherein the spindle (20) and/or a rotary sleeve (22) mounted thereon has a radially disposed space, into which a radially guidable locking pin (33) engages,
   characterized in
   that a pressure medium may be introduced into the space in front of the locking pin (33) and hence the space takes the form of a pressure space (31.1, 31.2).
2. Working cylinder according to claim 1, characterized in that the locking pin (33) is loaded with pressure on the other side of the pressure space (31.1) by an energy storage mechanism (34).
3. Working cylinder according to claim 2, characterized in that the energy storage mechanism is a helical spring (34).
4. Working cylinder according to claim 2, characterized in that the energy storage mechanism is a hydraulic or pneumatic pressure source that discharges into a pressure space behind the locking pin.
5. Working cylinder according to at least one of claims 1 to 4, characterized in that the locking pin (33) is guided with play in the pressure space (31.1).
6. Working cylinder according to at least one of claims 1 to 5, characterized in that the pressure space (31.1, 31.2) has a conical base (32).
7. Working cylinder according to at least one of claims 1 to 6, characterized in that a plurality of pressure spaces (31.1, 31.2) are distributed radially around the spindle (20) and/or around the rotary sleeve (22) and are connected to a port of a pressure source.
8. Working cylinder according to claim 7, characterized in that more than one locking pin (33) is provided in a radially guidable manner.
9. Working cylinder according to claim 8, characterized in that a spacing between two locking pins is not equal to the spacing between two pressure spaces.
10. Working cylinder according to at least one of claims 1 to 8, characterized in that the spindle (20) and/or the rotary sleeve (22) forms an annular collar (26) that is supported at least remote from the piston (14) against a bearing, in particular needle bearing (30).
11. Working cylinder according to at least one of claims 1 to 10, characterized in that the spindle (20) and/or the rotary sleeve (22) rotates in a blind hole (23) in the housing (1) and maintains a distance from a blind hole base (25).
12. Working cylinder according to claim 11, characterized in that in the blind hole (23) a locking pressure space (38) is formed in the direction of the spindle (20) and/or the rotary sleeve (22).
13. Working cylinder according to at least one of claims 4 to 11, characterized in that the pressure space (31.1) and/or the locking pressure space (38) in front of the locking pin (33) and the pressure space in front of the piston (14) are connected to the same pressure source.
14. Working cylinder according to at least one of claims 1 to 13, characterized in that the pressure space (31.1, 31.2) is separated from the main pressure space (36) in front of the piston (14) by means of a seal (40).
15. Working cylinder according to at least one of claims 1 to 14, characterized in that the main pressure space (36) in front of and/or behind the piston (14) is protected by means of a load-holding valve (35).
16. Working cylinder according to at least one of claims 1 to 15, characterized in that the pressure space (31.1, 31.2) is loadable with a higher pressure than the main pressure space (36).
17. Working cylinder according to claim 16, characterized in that the main pressure space (36) is loadable with pressure only after the pressure in the pressure space (31.1, 31.2) has reached a predetermined value.

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