Pressing tool, system and method for producing a tight connection of a press connector to a workpiece

Abstract

The invention relates to a system for producing a sealed connection of a press connector to a workpiece, in particular to a pipe, preferably to a plastic pipe, with a pressing tool for pressing a press connector and with a pressure tool for driving the pressing tool. The pressure tool is arranged to output a hydraulic pressure at a pressure generation point The pressing tool is arranged to receive a hydraulic pressure at a pressing location and to press a press connector accordingly. The pressure tool and the pressing tool are connected via a hydraulic pressure transmission connection, the pressure generation location and the pressing location being remote from each other. A corresponding method for producing a tight connection of a press connector to a workpiece, in particular to a pipe made of a flexible material, preferably a plastic pipe, as well as a press force translator and a press tool are also described.

Claims

1. A system for producing a tight connection of a press connector to a workpiece, the system comprising: a pressing tool for pressing a press connector; and a pressure tool for driving the pressing tool, wherein the pressure tool is arranged to output a hydraulic pressure at a pressure generation location, wherein the pressing tool is arranged to receive a hydraulic pressure at a pressing location and to press a press connector accordingly, and wherein the pressure tool and the pressing tool are connected via a hydraulic pressure transmission connection, and wherein the pressure generation point and the injection point being remote from each other, wherein the pressing tool comprises at least two opposing pressing sections with a variable distance to each other and a pre-tensioning member, wherein the pressing tool is arranged to take at least three states, wherein in a first state the pre-tensioning member is tightened and the pressing sections are spaced apart, wherein, in a second state, the pressing sections are tightened by relaxing the pre-tensioning member into engagement with a press connector, wherein in a third state the press sections exert a lifting force towards each other on the press connector, and wherein in the second state, the press connector is connected in a twist-proof manner to a workpiece to be connected.

2. The system according to claim 1, wherein the pressure transmission connection is at least partially formed from a flexible material.

3. The system according to claim 1, wherein the pressure transmission connection comprises a hydraulic hose, and wherein the hydraulic hose is connected to the pressure tool and to the pressing tool.

4. The system according to claim 3, wherein the hydraulic hose is connected to the pressure tool and to the pressing tool in each instance via a flat-face connection.

5. The system according to claim 1, wherein the pressure tool is designed as a hand tool with a press hand tool and with a press force translator, wherein the pressing hand tool is arranged to generate and transmit a lifting force at the pressing force translator, and wherein the pressing force translator is arranged to translate a lifting force transmitted from the pressing hand tool into a hydraulic pressure and to output it.

6. The system according to claim 1, wherein the pressing tool is arranged to translate a pressure transmitted by the pressure transmission connection into a lifting force, and to press a press connector by exerting the lifting force.

7. The system according to claim 1, wherein the pressure tool is arranged to switch off when a limit value for the variable distance between the pressing sections of the pressing tool is reached.

8. The system according to claim 1, wherein the workpiece is a pipe.

9. The system of claim 1, wherein the workpiece is a plastic pipe.

10. A pressing tool for pressing a press connector, the pressing tool comprising: a housing; a connecting element for receiving a hydraulic pressure; a translation member designed to translate a received hydraulic pressure into a lifting force; and at least two pressing sections for pressing a press connector at a pressing location, wherein the connecting element is arranged for connection to a pressure transmission connection which is at least partially formed from flexible material, wherein a pre-tensioning member is provided for pre-tensioning the at least two pressing sections, wherein a pre-tensioning handle is provided for pre-tensioning the pre-tensioning member, and wherein, when the pre-tensioning member is pre-tensioned, the first pressing section is moved away from the second pressing section and, when the pre-tensioning member is released, the first pressing section is moved towards the second pressing section.

11. The pressing tool according to claim 10, wherein the at least two press sections are designed for lateral engagement with the press connector.

12. The pressing tool according to claim 10, wherein the at least two pressing sections are designed to be movable relative to each other, whereby the relative movement is restricted by a certain minimum distance of the pressing sections from each other, and wherein the minimum distance is determined as a function of the press connector to be pressed.

13. The pressing tool according to claim 10, wherein the pressing tool is designed for use in a system for producing a sealed connection with a workpiece.

14. The pressing tool according to claim 13, wherein the workpiece is a pipe.

15. The pressing tool according to claim 13, wherein the workpiece is a plastic pipe.

16. A method for producing a tight connection of a press connector to a workpiece, the method comprising the steps of: outputting a hydraulic pressure at a pressure generation point; transferring the hydraulic pressure from the pressure generating location to a pressing location remote from the pressure generating location; and taking up the hydraulic pressure at a pressing point in order to enable the press connector to be pressed accordingly, wherein prior to the output of the hydraulic pressure: a press connector is inserted at an interface between two pipe ends, a pressing tool is pre-tensioned and the pressing tool is inserted and released at the press connector, and wherein the press connector is connected to a workpiece in a twist-proof manner by releasing a clamping force of the pressing tool.

17. The method according to claim 16, in which a first lifting force is generated at the pressure generation point and is translated into a hydraulic pressure, and in which the hydraulic pressure is translated into a second lifting force at the pressing location and the second lifting force is used to press the press connector, wherein the hydraulic pressure is transmitted from the pressure generation point to an injection point via a pressure transmission connection made of flexible material.

18. The method of claim 16, the method further comprising repeating the steps of: outputting the hydraulic pressure at the pressure generating point; and transferring the hydraulic pressure from the pressure generating location to the pressing location remote from the pressure generation location, until the press connector is in an intended pressed state.

19. The method according to claim 16, wherein when a predetermined limit value for the total lifting force exerted on the press connector is exceeded, the output of the hydraulic pressure is inhibited or prevented.

20. The method according to claim 16, wherein the workpiece is a flexible pipe.

21. The method according to claim 16, wherein the workpiece is a plastic pipe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The previously described features of the system, the press force translator, the press tool and the process apply to the system, to the press force translator, to the press tool as well as to the process. In addition, the individual features can be combined with each other. Further features and advantages of the present invention will be apparent from the following description of several examples of embodiments, reference being made to the accompanying drawing. The drawing shows

(2) FIG. 1 a system for producing a tight connection between a press connector and a workpiece;

(3) FIG. 2 a press force translator as part of a pressure tool of a system;

(4) FIG. 3a a pressing tool in a first state, in a lateral sectional view;

(5) FIG. 3b the pressing tool from FIG. 3a in a further (third) state, in a lateral sectional view;

(6) FIG. 4 a side view of the pressing tool from FIGS. 3a and 3b;

(7) FIG. 5 an example of a press connector attached to a pipeline in an unpressed, non-pretensioned state;

(8) FIG. 6 the press connector from FIG. 5 and the press tool from FIGS. 3a to 4 in the first state;

(9) FIG. 7 the press connector and the press tool from FIGS. 3a to 6 in a second state;

(10) FIG. 8 the press connector and the press tool from FIGS. 3a to 7 in a third state;

(11) FIG. 9 the press connector and the press tool from FIGS. 3a to 8 in a fourth state and

(12) FIG. 10 the press connector and the press tool from FIGS. 3a to 9, whereby the press tool is released.

DESCRIPTION OF THE INVENTION

(13) FIG. 1 shows a system 2 for producing a sealed connection between a press connector 10 and a workpiece 4 in the form of a pipeline 6 made of plastic. The system 2 has a pressing tool 8 for pressing the press connector 10 and a pressure tool 12 for driving the pressing tool 8. The compression connector 10 is attached to the pipeline 6 and the compression tool 8 is attached to the compression connector 10. The pressure tool 12 is designed as a hand tool and is connected to the pressing tool 8 via a pressure transmission connection 14. The place where the pressure tool 12 is located is referred to below as the pressure generation location 16 and the place where the pressing tool 8 is located is referred to as the pressing location 18.

(14) The pressure generation point 16 and the injection point 18 are distant from each other, both in terms of height and horizontally.

(15) The pressure tool 12 is formed as a hand tool 20 and has a pressing force translator 22 and a pressing hand tool 24. The pressure transmission connection 14 is at least partially made of flexible material.

(16) In the following, the pressing force translator 22 of the pressing tool 12 and the pressing tool 8 as well as their mode of operation are explained in more detail.

(17) FIG. 2 shows a press force translator 22 as part of a press tool 12 of a system 2. The press force translator 22 has a housing 26, a connecting section 28 for receiving a lifting force and for connection to a press hand tool 24, a valve block 30, a pump plunger 32 as a translation means for 34 translating a received lifting force into a hydraulic pressure, a compression spring 36, a connecting member 38 for outputting a hydraulic pressure, a check valve 40 and two check valves 42a, 42b.

(18) To produce the press force translator 22 shown in FIG. 2, the pump plunger 32 is pushed into the valve block 30 together with the compression spring 36 and secured with a grub screw 44. Then check valves 42a, 42b are screwed into holes provided for this purpose. Subsequently, the stop valve 40, which has a ball bearing ball 46 and which is sealed at one end by a sealing element 48, is mounted and secured by a circlip 50. On one outlet side of the valve block 30, a flat-face connection 52 is fitted for connection to a hydraulic hose 14. Further bores of the valve block 30 are sealed by means of VSTI screw connections (“sealing plugs for screw-in holes”).

(19) The valve block 30 has an interior 54 in which the pump plunger 32 can be moved in a forward direction and in an opposite reverse direction. An area 56 of the interior 54 left free by the pump plunger 32 is provided for receiving oil. The volume of this area varies with the position of the pump plunger 32 in the interior 54.

(20) The press force translator 22 is connected to a press hand tool 24 (not shown in FIG. 2). For this purpose, the press force translator 22 is connected to the press hand tool 24 on one side of the valve block via the connecting section 28, whereby the connecting section 28 is arranged opposite the end of the valve block which has the flat-face connection 52. The connection between the connecting section 28 and the press hand tool 24 is made via a locking pin 60.

(21) The pressure transmission connection 14 is connected to the other end of the pressing force translator 22, which is connected to the pressing tool 8 at the other end.

(22) Activating the pressing hand tool 24 pushes the pump plunger 32 axially into the valve block 30. This movement displaces oil located in the valve block 30 or in the interior 54 so that the oil flows through the check valve 42a and the flat-face connection 52 into the pressure transmission connection 14 to then enter the pressing tool 8. The check valve 42a restricts the flow of oil during a movement of the pump ram 32 towards the flat-face connection 52. In addition, the manually operated check valve 40 is tightly closed during the entire pressing process.

(23) As soon as the movement of the part of the pressing tool 24 connected to the pump plunger 32 or to the connecting section 28 has been completed, i.e. in the state as shown in FIG. 2, the pump plunger 32 moves out of the valve block 30 by the spring force of the compression spring 36. At this point, the check valve 42a blocks a backflow of oil into the interior 54 of the valve block 30, so that the hydraulic pressure generated during the forward movement of the pump plunger 32 in the direction of the pressing tool 8 remains in the pressure transmission connection 14.

(24) When the pump plunger 32 is moved back, i.e. when the pump plunger 32 is extended out of the valve block 30 in the direction of the press hand tool 24, a negative pressure is created in the interior 54, which causes the check valve 42b to open. This allows oil, originally located in a space 62 between a bellows 64 and an outer portion 66 of the valve block 30, to flow into the interior 54 through the bore in which the check valve 42b is located. When the pump plunger 32 is extended, the inner chamber 54 is filled with oil again and the stroke of the pump plunger 32 is completed.

(25) After reaching a predetermined maximum operating pressure in the inner chamber 54, the shut-off valve 40 can be opened manually so that oil flows out into the intermediate chamber 62 under pressure relief. Preferably, the maximum operating pressure is reached after three strokes of the pump plunger 32. However, an oil volume designed for more than three strokes may be provided so that further pressing hand tools with a higher oil requirement can be used if necessary. The hydraulic hose is supplied pre-filled with a predetermined volume of oil so that air bubbles in the hydraulic system can be avoided. The oil remains in the line until the hose is connected, only then does the Flat-Face coupling release the oil.

(26) FIG. 3a shows a pressing tool 8 in a lateral sectional view. The pressing tool 8 has, among other things, a housing 68, a flat-face connection 70 as a connecting element 72 for receiving a hydraulic pressure, a cylinder tube 74, transmission means 78 in the form of a piston 76, a piston rod 80, a joint piece 82, a compression spring 84 and a pretensioning spring 86 as a pretensioning element 88 for pretensioning the pressing tool 8.

(27) To produce the pressing tool 8 shown in FIG. 3a, the piston rod 80, which is screwed to the piston 76, is inserted into the cylinder tube 74 together with the compression spring 84. To close the cylinder barrel, 74a cover 90 is attached or screwed to a distal end of the cylinder barrel 74. A space in the cylinder barrel 74, located around the piston rod 80 and partially restricted by the base 92 of the piston 76 forms a hydraulic chamber 94.

(28) Then a connection ring 96 with mounted flat-face connection 70 is pushed over the cylinder barrel 74 as far as it will go and secured with a circlip 98. The connection ring 96 can be rotated through 360° and has two O-rings and for sealing its connection with the cylinder tube 74. Then a first cantilever arm 100 with a first press section 102 and a bolt 104 is pushed over the cylinder barrel 74.

(29) Next, the preload spring 86 is attached. For this purpose, the preload spring 86 is screwed to the cylinder tube 74 with a stop element 106. Next, the joint piece 82 is connected to the piston rod 80 by means of a bolt 108. In the next step, a sleeve 110 is screwed to the cylinder barrel 74. Lastly, a second cantilever 112 with a second press section 114 and a bolt 116 is slid over the sleeve 110 and connected to the joint piece 82 by means of a bolt 118, so that the first press section 102 of the first cantilever 100 and the second press section 114 of the second cantilever 112 are arranged opposite each other.

(30) FIG. 3a shows the pressing tool 8 in a state in which the pressing sections 102, 114 are at a predetermined distance from each other.

(31) FIG. 3b shows the pressing tool 8 in a state in which the pressing sections 102, 114 have a smaller distance to each other. Oil, which is in the hydraulic chamber 94, presses on the bottom 92 of the piston 76 in the direction of the cover 90. In its movement, the piston 76 drives the piston rod 80 and thus the joint piece 82 and the second cantilever arm 112 with the second pressing section 114 in the direction of the first pressing section 102. The stop element 106 restricts the axial movement of the first pressing section 88, so that during pressing the second pressing section 114 presses a press connector to be pressed against the first pressing section 102.

(32) FIG. 4 shows a side view of the pressing tool 8, wherein a pre-tensioning handle 122 is provided. The pretensioning handle 122 is adapted to be used as a transport handle for the pressing tool 8 and can be tightened manually. Pulling the pretensioning handle 122 causes compression of the pretensioning spring 86.

(33) The pressing tool 8 can be used as follows.

(34) First, the pressing tool is brought into a first state shown in FIG. 3a. For this purpose, the pretensioning spring 86 is tensioned or compressed, if necessary by tightening the pretensioning handle 122. Then the press sections 102, 114, thus moved apart, are brought into engagement with a press connector 10 by at least partially relaxing the pretensioning spring 86, as explained in more detail in connection with FIGS. 5 to 10. By releasing the pretensioning spring 86 or, if applicable, by releasing the pretensioning handle 122, the press sections 102, 114 grip the press connector 10 with a pretensioning force corresponding to the spring constant of the pretensioning spring 86, so that the press tool is in a second state.

(35) In a next step, the pressing tool is brought into a third state, which is shown in FIG. 3b. For this, an oil displaced by the press force translator 22 is directed through the flat-face connection 52 via the connection ring 96 to the hydraulic chamber 94 in the cylinder tube 74. The oil transmits a hydraulic pressure to the bottom 92 of the piston 76 and moves it in the direction of the cover 90 of the cylinder tube 74 against the force of the compression spring 84 with a corresponding lifting force. The piston 76 drives the piston rod 80 with the lifting force corresponding to the hydraulic pressure exerted on the piston 76. The movement of the piston rod 80 causes a movement of the joint piece 82, which in turn drives the second cantilever 112. Thus, the second cantilever 112 is moved together with the second pressing section 114 in the direction of the first pressing section 102 and thus the press connector 10 is pressed.

(36) FIGS. 5 to show 10 the successive states that a press tool 8 described above assumes when carrying out a process for producing a sealed connection of a press connector to a workpiece, and the corresponding effect on a press connector 10.

(37) FIG. 5 shows an initial situation in which a press connector 10 with a cutting half-ring 124 is attached to a pipeline 6, but is neither pretensioned nor pressed.

(38) In FIG. 6 the pressing tool 8 is in the first state. The pressing tool 8 is pretensioned, possibly by pulling a pretensioning handle 122, and the pressing sections 102, 114 are moved apart. The pressing sections 102, 114 are moved away from each other to such an extent that the cantilever arm 100, which supports the pressing section 102, abuts against the stop element 106. Pulling the pretensioning handle 122 or tightening the pretensioning element 88 produces a predefined pretensioning force. The press connector 10 is further neither preloaded nor pressed.

(39) FIG. 7 shows the pressing tool 8 and the press connector 10 in the second state. The pretensioning element 88 of the pressing tool 8 is relaxed, the pretensioning handle 122 has been released if necessary. During relaxation, the first cantilever arm 100 together with the first pressing section 102 has moved in the direction of the second pressing section 114, so that the distance between the pressing sections 102, 114 is smaller than in the state shown in FIG. 6. The press sections 102, 114 are each engaged with an interference fit 126, 128 of the press connector 10. Due to the spring force of the pretensioning element 88, the press connector 10 is partially compressed and the press tool 8 remains in engagement with the press seats 126, 128. The cutting collar 124 of the press connector 10 penetrates the surface of the pipeline 6 so that the press connector 10 is attached to the pipeline 6 in an anti-rotational manner. As a result, the press connector 10 is pre-tensioned but not pressed.

(40) The pressing tool 8 is then connected to the pressing force translator 22 of the pressing tool 12 via a hydraulic hose as a pressure transmission connection 14 with a flat-face connection.

(41) FIG. 8 shows the pressing tool 8 and the press connector in the third state. Here, the pressing tool 8 receives hydraulic pressure from the pressing tool 12 through its flat-face connection 70 and translates this pressure into a lifting force. The pressing tool 8 exerts the lifting force through the pressing sections 102, 114 onto the respective press fit 126, 128 of the press connector 10. Thus, the press connector 10 is pressed.

(42) In FIG. 9, the pressing tool 8 exerts sufficient lifting force on the press connector 10 to press the press connector 10 as intended. In the intended pressed state, sealing elements of the press connector 10, which are arranged on the inner surface of the press connector 10, are pressed against the outer wall of the pipeline 6. As a result, the press connector 10 lies tightly against the pipeline 6 A securing element 130 has been attached to the press connector 10, which holds the press connector 10 in the pressed state. Thus the press connector 10 is pressed and secured. Thus the pressing tool 8 and the press connector 10 are in a fourth state.

(43) The securing element 130 can be pushed laterally onto the press connector 10. Preferably, the securing element can be pushed with one hand.

(44) In FIG. 10 the press connector 10 is pressed and secured. The pressing tool 8 no longer exerts a lifting force on the press connector 10. Furthermore, the pressing tool 8 is clamped, if necessary by pulling the pretensioning handle 122, so that the pressing sections 102, 114 are moved away from each other. In this state, the pressing tool 8 can be easily removed or released from the press connector 10. Alternatively, after pressing, the pressing tool 8 can be removed from the connector 10 without re-tensioning.

(45) In the following, a use of system 2 is described as an example.

(46) First, a first lifting force is translated into a hydraulic pressure by means of the pressure tool 12 and transmitted to the pressing tool 8 via the pressure transmission connection 14. Then the pressing tool 8 takes up the hydraulic pressure and translates it into a corresponding second lifting force. The second lifting force is sufficient to counteract or overcome the force of the pre-tensioning spring 86 and to move the first cantilever arm 100 up to the stop element 106.

(47) Subsequently, the press connector 10 is pressed by a predefined minimum number of strokes at the pressing tool 12 or a predefined minimum number of actuations of the pressing tool 12. Over-pressing” by too many strokes is prevented by a limitation based on a predetermined distance between the pressing sections 102, 114 of the pressing tool. Accordingly, the pressing tool 12 or the pressing hand tool 24 of the pressing tool 12 switches off automatically when an operating pressure corresponding to the predetermined distance between the pressing sections 102, 114 of the pressing tool 8 is reached.

(48) As soon as this operating pressure is reached and the finished pressing dimension of the press connector 10 or the predetermined distance between the pressing sections 102, 114 is reached, a locking element 130 can be inserted. Finally, the pressing tool 8 is opened by turning open the locking valve 40 on the pressing force translator 22. This allows the oil from the pressing tool 8 to flow back into the tank 64 via the pressure transmission connection 14 to the pressing force translator 22 through the open channel of the open shut-off valve 40.