Pressing tool with switchblade bistable tensioning mechanism

Abstract

A pressing tool for joining a pipe and a fitting, including two swivel elements for pressing the pipe and the fitting, a receiving region, formed between the swivel elements, for receiving the pipe and the fitting, at least one swivel axis for rotatably mounting the swivel elements, and a tensioning mechanism for pretensioning the pressing tool. The swivel elements can be swivelled towards one another about the at least one swivel axis to press the pipe and the fitting. In a first, closed position, the receiving region is narrower than in a second, open position, of the swivel elements, wherein the swivel elements are pretensioned towards the closed position by the tensioning mechanism. At least one holding device is provided for holding the swivel elements in the open position against the pretensioning force generated by the tensioning mechanism.

Claims

1. A pressing tool for joining a pipe and a fitting, comprising: two swivel elements for pressing the pipe and the fitting, a receiving region, formed between the swivel elements, for receiving the pipe and the fitting, at least one swivel axis for rotatably mounting the swivel elements, and a tensioning mechanism for pretensioning the pressing tool, wherein the swivel elements can be swivelled relative to one another about the at least one swivel axis to press the pipe and the fitting, wherein in a first, closed position, the receiving region is narrower than in a second, open position, of the swivel elements, wherein the swivel elements are pretensioned toward the closed position by the tensioning mechanism, and wherein at least one holding device is provided for holding the swivel elements in the open position against a pretensioning force generated by the tensioning mechanism, wherein the at least one holding device is switchable between a first operating mode in which the tensioning mechanism, but not the at least one holding device, acts on the swivel elements and a second operating mode in which the at least one holding device and the tensioning mechanism form a switchable, bistable tensioning mechanism wherein the at least one holding device has in the open position of the swivel elements a first switch position in which the tensioning mechanism is released, wherein the at least one holding device has in the open position of the swivel elements a second switch position in which the at least one holding device works against the tensioning mechanism, wherein the at least one holding device is braced resiliently in the second switch position, wherein the at least one holding device has at least one locking element and at least one locking recess, the at least one locking element interacting with the at least one locking recess in the second switch position, and wherein the at least one locking element and the at least one locking recess of the at least one holding device are provided on two different components, these components being swivellable about the at least one swivel axis relative to one another and at least one of the components being one of the swivel elements.

2. A pressing tool for joining a pipe and a fitting, comprising: two swivel elements for pressing the pipe and the fitting, a receiving region, formed between the swivel elements, for receiving the pipe and the fitting, at least one swivel axis for rotatably mounting the swivel elements, and a tensioning mechanism for pretensioning the pressing tool, wherein the swivel elements can be swivelled relative to one another about the at least one swivel axis to press the pipe and the fitting, wherein in a first, closed position, the receiving region is narrower than in a second, open position, of the swivel elements, wherein the swivel elements are pretensioned toward the closed position by the tensioning mechanism, and wherein at least one holding device is provided for holding the swivel elements in the open position against a pretensioning force generated by the tensioning mechanism, wherein the at least one holding device is switchable between a first operating mode in which the tensioning mechanism, but not the at least one holding device, acts on the swivel elements and a second operating mode in which the at least one holding device and the tensioning mechanism form a switchable, bistable tensioning mechanism, wherein the at least one holding device has in the open position of the swivel elements a first switch position in which the tensioning mechanism is released, wherein the at least one holding device has in the open position of the swivel elements a second switch position in which the at least one holding device works against the tensioning mechanism, wherein the at least one holding device is braced resiliently in the second switch position, wherein the at least one holding device has at least one locking element and at least one locking recess, the at least one locking element interacting with the at least one locking recess in the second switch position, and wherein the at least one locking element is a substantially cylindrical bolt and the locking recess is a depression formed in a leaf spring.

3. The pressing tool according to claim 2, wherein the bolt can be displaced in an axial direction between the first switch position and the second switch position, the bolt being at a distance from the leaf spring in the first switch position and resting peripherally on the leaf spring in the second switch position.

4. The pressing tool according to claim 2, wherein the bolt rests on a guide rail which holds the bolt in the respective axial switch position.

5. The pressing tool according to claim 4, wherein the guide rail is a leaf spring.

6. The pressing tool according to claim 4, wherein the bolt has on a portion associated with the guide rail two mutually spaced apart, peripherally running grooves which interact with a guide path of the guide rail in the respective switch position.

7. A pressing tool for joining a pipe and a fitting, comprising: two swivel elements for pressing the pipe and the fitting, a receiving region, formed between the swivel elements, for receiving the pipe and the fitting, at least one swivel axis for rotatably mounting the swivel elements, and a tensioning mechanism for pretensioning the pressing tool, wherein the swivel elements can be swivelled relative to one another about the at least one swivel axis to press the pipe and the fitting, wherein in a first, closed position, the receiving region is narrower than in a second, open position, of the swivel elements, wherein the swivel elements are pretensioned toward the closed position by the tensioning mechanism, and wherein at least one holding device is provided for holding the swivel elements in the open position against a pretensioning force generated by the tensioning mechanism, wherein the at least one holding device is switchable between a first operating mode in which the tensioning mechanism, but not the at least one holding device, acts on the swivel elements and a second operating mode in which the at least one holding device and the tensioning mechanism form a switchable, bistable tensioning mechanism, wherein the at least one holding device has in the open position of the swivel elements a first switch position in which the tensioning mechanism is released, wherein the at least one holding device has in the open position of the swivel elements a second switch position in which the at least one holding device works against the tensioning mechanism, wherein the at least one holding device is braced resiliently in the second switch position, wherein the at least one holding device has at least one locking element and at least one locking recess, the at least one locking element interacting with the at least one locking recess in the second switch position, and wherein the at least one locking element has a sliding element which is slidably guided on one of the swivel elements, the sliding element being displaceable between the first switch position and the second switch position, and the at least one locking recess being formed in the other one of the swivel elements.

8. The pressing tool according to claim 7, wherein the sliding element is held pretensioned in the first switch position.

9. The pressing tool according to claim 7, wherein the swivel elements are provided with two sliding elements and wherein the at least one locking element includes two locking recesses.

10. A pressing tool for joining a pipe and a fitting, comprising: two swivel elements for pressing the pipe and the fitting, a receiving region, formed between the swivel elements, for receiving the pipe and the fitting, at least one swivel axis for rotatably mounting the swivel elements, and a tensioning mechanism for pretensioning the pressing tool, wherein the swivel elements can be swivelled relative to one another about the at least one swivel axis to press the pipe and the fitting, wherein in a first, closed position, the receiving region is narrower than in a second, open position, of the swivel elements, wherein the swivel elements are pretensioned toward the closed position by the tensioning mechanism, and wherein at least one holding device is provided for holding the swivel elements in the open position against a pretensioning force generated by the tensioning mechanism, wherein the at least one holding device is switchable between a first operating mode in which the tensioning mechanism, but not the at least one holding device, acts on the swivel elements and a second operating mode in which the at least one holding device and the tensioning mechanism form a switchable, bistable tensioning mechanism, wherein the at least one holding device has in the open position of the swivel elements a first switch position in which the tensioning mechanism is released, wherein the at least one holding device has in the open position of the swivel elements a second switch position in which the at least one holding device works against the tensioning mechanism, wherein the at least one holding device is braced resiliently in the second switch position, wherein the at least one holding device has at least one locking element and at least one locking recess, the at least one locking element interacting with the at least one locking recess in the second switch position, and wherein the at least one locking element is a pressure piece, the pressure piece having in particular a locking ball which is resiliently pretensioned in the first switch position and sits in a locking recess formed as a depression in the second switch position.

11. The pressing tool according to claim 10, wherein the pressure piece is attached to one of the swivel elements and the at least one locking recess is provided in a support element supporting the at least one swivel axis.

12. The pressing tool according to claim 11, wherein a second pressure piece is provided which counteracts a swivelling movement of the swivel elements out of the closed position into the open position in a swivel range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention will be described in more detail with reference to embodiments shown in the drawings, in which:

(2) FIGS. 1a, 1b are two perspective views of a first embodiment of a pressing tool according to the invention in the closed position, with holding devices in a first switch position;

(3) FIGS. 1c, 1d are two perspective views of enlarged details of the pressing tool from FIG. 1a and FIG. 1b in the closed position, with the holding devices in the first switch position;

(4) FIGS. 2a, 2b are two perspective views of the pressing tool from FIG. 1 in an open position, with the holding devices in the first switch position;

(5) FIGS. 2c, 2d are two perspective views of enlarged details of the pressing tool from FIG. 2a and FIG. 2b in an open position, with the holding devices in the first switch position;

(6) FIGS. 3a, 3b are two perspective views of enlarged details of the pressing tool in an open position, with the holding devices in a second switch position;

(7) FIGS. 4a, 4b are two perspective views of enlarged details of the pressing tool in the closed position, with the holding devices in the second switch position;

(8) FIG. 5 is a perspective view of a second embodiment of a pressing tool according to the invention in the closed position;

(9) FIG. 6a is a side view of the pressing tool from FIG. 5 in the closed position, with holding devices in a first switch position;

(10) FIG. 6b is a side view of the pressing tool from FIG. 5 in an open position, with the holding devices in the first switch position;

(11) FIG. 6c shows the pressing tool from FIG. 5 in an open position, with the holding devices in a second switch position;

(12) FIG. 7a is a sectional view of the holding devices along line VIIa-VIIa from FIG. 6a;

(13) FIG. 7b is a sectional view of the holding devices along line VIIb-VIIb from FIG. 6b;

(14) FIG. 7c is a sectional view of the holding devices along line VIIc-VIIc from FIG. 6c;

(15) FIG. 8a is a side view of a third embodiment of a pressing tool according to the invention in the closed position;

(16) FIG. 8b is a side view of the pressing tool from FIG. 8a in an open position;

(17) FIG. 8c is a side view of the pressing tool from FIG. 8a in an open position;

(18) FIG. 9 is a side view of a fourth embodiment of a pressing tool according to the invention in a closed position.

DETAILED DESCRIPTION OF THE INVENTION

(19) FIG. 1 shows two perspective views of an embodiment of a pressing tool 2 according to the invention for joining a pipe (not shown) and a fitting (not shown), in a closed position with holding devices 20a in a first switch position A.

(20) The pressing tool 2 has two swivel elements 4 for pressing the pipe and the fitting. The pressing tool 2 has a receiving region 6, formed between the swivel elements 4, for receiving the pipe and the fitting. The swivel elements 4 each have a pressing portion 8 and an actuating portion 10. In practical use, the actuating portions 10 are used to introduce the pressing forces via a machine (not shown). The inner contours 12 of the pressing portions 8 form the receiving region 6. During the pressing procedure, the receiving region 6 is transferred from an open position (FIG. 2) into a closed position (FIG. 1), the receiving region 6 being narrower in the closed position of the swivel elements 4 than in the open position of the swivel elements 4.

(21) Located between the swivel elements 4 is an tensioning mechanism 14 (not shown) located on the inside which comprises a pretensioning spring for pretensioning the pressing tool 2 towards the closed position. The swivel elements 4 are mounted rotatably on the swivel axes 16. The swivel elements 4 can be swivelled about the swivel axes 16 towards to one another for pressing the pipe and the fitting. The swivel axes 16 are mounted in the support elements 18.

(22) The pressing tool 2 has two holding devices 20a for holding the swivel elements 4 in the open position (FIG. 3) against the force generated by the pretensioning spring, the holding devices 20a being switchable. The holding devices 20a and the tensioning mechanism 14 form a switchable, bistable tensioning mechanism.

(23) The respective holding device 20a has a locking element 22a and at least one locking recess 24a. The locking element 22a is a substantially cylindrical bolt 22a and the locking recess 24a is a depression 24a formed in a leaf spring 26. The leaf spring 26 is held in a positive fit by its end portions 28, which are bent back substantially circularly at the ends, in a mount 30 of the support element 18, at least portions of said mount being formed in a complementary manner.

(24) The respective bolt 22a of one of the holding devices 20a rests on a guide rail 32 which secures the bolt 22a in an axial direction along the axis a of the bolt 22a against an undesirable movement. The guide rail 32 is a leaf spring 32 which is attached to the support element 18 opposite the leaf spring 26. The bolt 22a has on its portion 34 associated with the guide rail 32 two mutually spaced apart, peripherally running grooves 36a, 36b which interact with a guide path 38 of the guide rail 32. The guide path 38 is curved towards the bolt 22a. The grooves 36a, 36b have a respective groove cross section which is formed in a substantially complementary manner to the curvature of the guide path 38. The guide path 38 and the grooves 26a, 26b engage in a positive fit with each other. Bolt 22a is secured against displacement in an axial direction by the guide path 38 and the grooves 36a, 36b. Therefore, when the swivel elements 4 are swivelled relative to the support element 18, bolt 22a is guided along the guide path 38 relative to the support elements 18.

(25) FIG. 2 shows the pressing tool 2 from FIG. 1 in an open position, with the holding devices 20a in the first switch position A. FIG. 3 shows two perspective views of enlarged details of the pressing tool 2 from FIG. 1 in an open position, with the holding devices 20a in a second switch position B. The bolts 22a of the holding devices 20a are displaceable in an axial direction between the first switch position A and the second switch position B, said bolts 22a being at a distance from the leaf spring 26 in the first switch position A and resting peripherally on the leaf springs 26 in the second switch position B.

(26) To swivel the swivel elements 4 out of the closed position (FIG. 1) into the open position (FIG. 2, FIG. 3), a user has to press the swivel elements 4 together in the region of the actuating portions 10 against the pretensioning force of the tensioning mechanism 14. The actuating portions 10 are moved towards one another while the pressing portions 8 are spread apart and thus the receiving region 6 is opened.

(27) In switch position A of the holding devices 20a shown in FIG. 2, the holding devices 20a do not counteract the tensioning mechanism 14 and the tensioning mechanism 14 is released. When the user releases the actuating portions 10 in the open position of the swivel elements 4, said swivel elements 4 are moved back into the closed position due to the resilient force of the tensioning mechanism 14 (FIG. 1). The respective bolt 22a is also guided by a guide portion 40 which projects over the width of the leaf spring 26 in the first switch position A and has a circularly running web 42 which rests laterally on the leaf spring 26.

(28) The holding devices 20a allow the user to fix the swivel elements 4 in a resiliently braced manner in the open position. For this purpose, in the open position, the bolts 22a are moved along their respective axis a in an axial direction out of switch position A into switch position B which is shown in FIG. 3.

(29) The axes a of the bolts 22a and the swivel axes 16 run substantially parallel to one another. The bolts 22a are guided such that they slide in the holes 44 in the respective swivel element 4. When a bolt 22a is moved out of switch position A into switch position B, the groove 36a encompassing the guide path 38 in switch position A slides on the guide path 38 with the groove inner face rising against the direction of movement and presses the guide rail 32 towards the support element 18. The bolt 22a is moved towards switch position B until the guide rail 32 engages with the guide path 38 in the respective other groove 36b. In this respect, the bolt 22a sits with a partial length of the portion 34 in a guide depression 46 which is formed in the swivel element 4 and against which the bolt 22a is laterally supported during the swivelling movement of the swivel elements 4.

(30) The diameter of portion 48 of the bolt 22a contacting the leaf spring 26 in switch position B (FIG. 3) substantially corresponds to the diameter of the hole 44. Starting from the diameter of the bolt portion 48, the bolt 22a is tapered conically towards the guide portion 40 so that a circularly running bevel 50 is provided between the bolt portion 48 and the guide portion 40. When a respective bolt 22a is moved out of switch position A into switch position B, the bolt with bevel 50 threads into the depression 24a to ensure the correct position of the bolt 22a. When the bolt 22a is pushed onto the leaf spring 26, the bolt 22a, with the help of the bevel 50, displaces the leaf spring 26 towards the support element 18 so that the bolt 22a and the leaf spring 26 are braced against one another. In this respect, the bevel 50 slides on the side edge 52 of the leaf spring 26 facing the hole 44.

(31) FIG. 3 shows the pressing tool 2 with swivel elements 4 held in an open position, the bolts 22a being in switch position B. The bolts 22a rest in each case on the leaf springs 26 by their portion 48 associated with the leaf springs 26. The swivel elements 4 are supported on the support elements 18 by the bolts 22a and by the leaf springs 26. The leaf springs 26 are configured to be so rigid that they counteract a sliding movement of the bolts 22a along the leaf springs 26, which movement is caused by the force of the tensioning mechanism 14. In other words, the force introduced into the swivel elements 4 by the tensioning mechanism 14 or the moment, resulting therefrom, about the swivel axes 16 is insufficient to displace the leaf springs 26 towards the swivel axes 16 with the aid of the bolts 22a and thus is insufficient to move the swivel elements 4 out of the open position into the closed position. Consequently, the swivel elements 4 are held in a stable manner in the open position.

(32) To move the swivel elements 4 out of the open position into the closed position while the holding devices 20a are simultaneously in switch position B, an impulse or actuating power has to be introduced in the region of the actuating portions 10. This can be performed by a machine (not shown), for example, which engages between the actuating portions 10 and spreads these portions 10 apart. The actuating power applied to the actuating portions 10 supports the force of the tensioning mechanism 14. The bolts 22a displace the leaf springs 26 towards the swivel axes 16.

(33) After passing through an unstable intermediate position, the swivel elements 4 fall back into the closed position. The unstable intermediate position is the swivel position of the swivel elements 4 in which the forces and moments about the swivel axes 14, which are introduced into the swivel elements by the tensioning mechanism 14 and the holding devices 20 cancel each other out. During any change of the swivel elements 4 from the open position to the closed position or vice versa, the respective leaf spring 26 has to be displaced towards the support element 18 with the bolt 22a by an externally introduced actuating power to pass the unstable intermediate position of the swivel elements 4 towards the desired position of the swivel elements 4.

(34) During the movement of the swivel elements 4 out of the open position into the closed position, the bolt 22a is guided along the guide path 38 of the guide rail 32. Therefore, as the swivel elements 4 are changed from the open position to the closed position or vice versa. The bolt 22a remains in its engaged position (FIG. 4). The interaction between the guide rail 32 and the grooves 36a, 36b therefore also holds the bolt 22a in the respectively set switch position A or B for the subsequent pressing procedures. In the case described here, the bistable behaviour of the pressing tool 2 is maintained until the user actively moves the bolt 22a again out of switch position B into switch position A.

(35) FIGS. 5 and 6a are a perspective view and a side view of a further embodiment of a pressing tool 2 according to the invention in the closed position, with holding devices 20b in a first switch position A, and in the following, the same reference numerals are assigned to the same elements with reference to the first embodiment.

(36) The pressing tool 2 has two swivel elements 4 for pressing a pipe (not shown) and a fitting (not shown), with a receiving region 6, formed between the swivel elements 4, for receiving the pipe and the fitting. The swivel elements 4 are mounted rotatably about the swivel axes 16. The swivel axes 16 are supported by the support elements 18. The swivel elements 4 can be swivelled towards one another about the swivel axes 18 to press the pipe and fitting. A tensioning mechanism 14 arranged between the swivel elements 4 and the support elements 18 is used to pretension the pressing tool 2 towards the closed position.

(37) The pressing tool 2 has two holding devices 20b for holding the swivel elements 4 in the open position against the pretensioning force generated by the tensioning mechanism 14. The holding devices 20b are switchable, the holding device 20b and the tensioning mechanism 14 forming a switchable, bistable tensioning mechanism. The holding devices 20a have a respective locking element 22b and a locking recess 24b, the locking recess 24b being formed as a locking groove 24b. The locking element 22b is a sliding element 22b which is guided such that it is slidably movable on one swivel element 4.

(38) In order to more clearly understand the following information concerning the mode of operation of the holding device 20b, FIG. 7 shows respective sectional views of the switch positions described with reference to FIG. 6. FIG. 7a is a sectional view of the holding devices along line VIIa-VIIa from FIG. 6a. FIG. 7b is a sectional view of the holding devices along line VIIb-VIIb from FIG. 6b. FIG. 7c is a sectional view of the holding devices along line VIIc-VIIc from FIG. 6c.

(39) FIG. 6b shows the pressing tool 2 from FIG. 6a in an open position, with the holding devices 20b in the first switch position A. In the open position of the swivel elements 4 according to FIG. 2b, the receiving region 6 is wider than in the closed position of the swivel elements 4 from FIG. 2a.

(40) In the open position of the swivel elements 4 shown in FIG. 6b, the tensioning mechanism 14 is released because the holding devices 20b are in the first switch position A. In this state, the holding devices 20b do not work against the tensioning mechanism 14.

(41) To transfer the pressing tool 2 from the closed position of the swivel elements 4 shown in FIG. 6a into the open position of the swivel elements 4 shown in FIG. 6b, the user presses the swivel elements 4 together in the region of the actuating portions 10 without actuating the holding devices 20b. For this purpose, the user grasps and actuates the actuating portions 10 at their respective portions 54 mounted upstream of the holding devices 20b in the direction of the receiving region 6. In this case, the sliding elements 22b remain in the starting position shown in FIG. 6a relative to the swivel elements 4. In the open position of the swivel elements 4 shown in FIG. 6b, the sliding elements 22b do not engage in the locking grooves 24b in the swivel elements 4. As shown in the sectional views according to FIGS. 7a and 7b, the sliding elements 22b are held in the first switch position A, pretensioned by a helical compression spring 56.

(42) As long as the user actively holds the pressing tool 2 in the open position of the swivel elements 4 shown in FIG. 6b, with the holding devices 20b in the first switch position, the swivel elements 4 remain in the open position. If the user does not act on the pressing tool 2, the swivel elements 4 are swivelled back into the closed position shown in FIG. 6a due to the pretensioning force provided by the tensioning mechanism 14.

(43) FIG. 6c shows the pressing tool from FIG. 6a in an open position, with the holding devices 20b in the second switch position B. In the second switch position B, the holding devices 20 counteract the tensioning mechanism 14. The locking projections 58 of the sliding elements 22b engage in the locking grooves 24b. The respective sliding element 22b can be moved between the first switch position A and the second switch position B and is guided bilaterally on the associated swivel element 4 by a mandrel 60 in a groove 62.

(44) The holding devices 20b which have moved into switch position B hold the swivel elements 4 of the pressing tool 2 in the open position. To transfer the pressing tool 2 from the closed position shown in FIG. 6a into the open position shown in FIG. 6c, while simultaneously switching the holding devices 20b, the user actuates the actuating portions 10, from the position shown in FIG. 6a, in the region of the holding devices 20b. Therefore, the user presses the actuating portions 10 together via the two sliding elements 22b. In addition to a swivelling movement of the swivel elements 4 into the open position, the sliding elements 22b are simultaneously moved against the helical compression springs 56 towards the locking grooves 24b respectively provided in the opposite swivel elements 4.

(45) The holding devices 20b can be transferred in exactly the same way from switch position A shown in FIG. 6b into switch position B in that the sliding elements 22b are moved towards one another so that the locking projections 58 engage in the locking grooves 24b.

(46) In switch position B of the holding devices 20b shown in FIG. 6c, the pressing tool 2 is braced resiliently in the open position of the swivel elements 4. In this respect, the flexural spring portions 64 of the sliding elements 22b, supporting the locking projections 58 and resting on the swivel elements 4 counteract a sliding movement of the bevels 66 of the locking projections 42 on the edges 68 of the locking grooves 24b. Therefore, the swivel elements 4 are held in a stable manner in the open position.

(47) The swivel elements 4 can be transferred from the switch position shown in FIG. 6c into the closed position shown in FIG. 6a in that the actuating portions 10 are spread apart by means of a machine (not shown). For this purpose, the machine is coupled in a known manner to the coupling portions 70 of the support elements 18. The machine presses the actuating portions 10 apart, the bevels 66 sliding on the edges 68, and the holding forces of the flexural spring portions 64 are overcome thereby. As soon as the locking projections 58 no longer engage with the locking grooves 24b, the swivel elements 4 swivel back into the closed position due to the pretensioning force of the tensioning mechanism 14. For their part, the sliding elements 22b are moved back into the disengaged starting position shown in FIG. 6a due to the helical compression springs 56 and they are held, pretensioned, in this position by the helical compression springs 56.

(48) FIG. 8 shows a third embodiment of a pressing tool 2 according to the invention, and in the following, the same reference numerals are assigned to the same elements with reference to the above embodiments.

(49) FIG. 8a is a side view of the pressing tool 2 in the closed position. The pressing tool 2 has a holding device 20c formed by a pressure piece 22c and a depression 24c. The pressure piece 22c has a locking ball 72 which is resiliently pretensioned against a guide surface 74 formed on the support element 18. The pressure piece 22c is attached to the swivel element 4 and the depression 24c is provided in the support element 18 supporting the swivel axes 16. The guide surface 74 merges smoothly into the depression 24c. The pressure piece 22c has an external thread and is screwed into the swivel element 4.

(50) Provided on the swivel element 4 opposite the pressure piece 22c is a second pressure piece 76 which counteracts a swivelling movement of the swivel elements 4 out of the closed position into the open position in a swivel range, the open position in particular being part of this swivel range. The pressure piece 76 has a locking ball 78 which is configured to interact with a locking recess 80. The locking recess 80 formed as a depression is flat-shaped compared to the depression 24c.

(51) In the following, the actuation procedure of the pressing tool 2 will be described according to the third embodiment with reference to FIGS. 8a to 8c.

(52) In the closed position of the swivel elements 4 shown in FIG. 8a, the locking ball 72 rests in a resiliently pretensioned manner against the guide surface 74. Therefore, in the position shown in FIG. 8a, the pressure piece 22c is in a tensioned state. The locking ball 78 of the second pressure piece 76 is at a distance from the support element 18 and from the locking recess 80 formed therein. Pressure piece 76 is in a relaxed state. The swivel elements 4 are held in the closed position, pretensioned by the tensioning mechanism 14.

(53) In order to open the receiving region 6 to introduce a pipe and a fitting (not shown), the swivel elements 4 are pressed against one another in the region of the actuating portions 10 in order to swivel the swivel elements 4 about their respectively associated swivel axis 16 against the tensioning force of the tensioning mechanism 14.

(54) FIG. 8b shows the swivel elements 4 in an open position. In the swivel position of the swivel elements 4 shown in FIG. 8b, the pressure piece 22c is in the first switch position A. As in the closed position of the swivel elements 4 according to FIG. 8a, the locking ball 72 rests against the guide surface 74, remote from the swivel axis 16, of the support element 18. In switch position A, the pressure piece 22c does not substantially counteract a swivelling back movement of the swivel elements 4 into the closed position caused by the tensioning mechanism 14, because the smooth shape of the guide surface 74 which does not encompass the locking ball 72 promotes a rolling or sliding movement of the locking ball 72 along the guide surface 74.

(55) The swivelling movement of the swivel elements 4 moves the locking ball 78 of the second pressure piece 76 according to FIG. 8b into the locking recess 80, so that locking recess 80 at least partly encompasses the locking ball 78. However, the pressure piece 76 is still in a relaxed state, as it is in FIG. 8a.

(56) In the swivel position of the swivel elements 4 shown in FIG. 8b, the receiving region 6 is already so wide open that the pipe cross sections and fittings (not shown), provided to be pressed by the illustrated pressing tool 2, can be introduced into the receiving region 6.

(57) To fix the swivel elements 4 in the open position, the swivel elements 4 can be swivelled beyond the swivel position shown in FIG. 8b, as shown in FIG. 8c. In this swivel position of the swivel elements 4, the pressure piece 22c occupies the second switch position B, the locking ball 72 sitting in the depression 24c. The locking ball 72 is engaged in the depression 24c, so that the pressure piece 22c is in a relaxed state. Furthermore, according to further embodiments of a pressing tool according to the invention, the locking ball can also be held in the depression, braced by the spring provided in the pressure piece.

(58) The interaction of the pressure piece 22c with the depression 24c prevents the swivel elements 4 from swivelling back into the closed position by the tensioning mechanism 14. In other words, the force introduced into the swivel elements 4 about the swivel axes 16 by the tensioning mechanism 14 is insufficient to displace the locking ball 72 out of the depression 24c against the spring 82 of the pressure piece 22c or to move it out of the depression 24c by sliding.

(59) To move the swivel elements 4 back into the closed position shown in FIG. 8a, it is therefore necessary to spread the swivel elements 4 apart in the region of the actuating portions 10 by means of an additional force to overcome the clamping force of the holding device 20c. A force of this type can be provided, for example, by a machine, as already stated above with reference to the further embodiments.

(60) When the swivel elements 4 are swivelled out of the swivel position shown in FIG. 8b into the swivel position shown in FIG. 8c, the second pressure piece 76 forms an additional resistance which counteracts a swivelling movement of the swivel elements 4. Starting from the position shown in FIG. 8b, the locking ball 80 of the second pressure piece 76 has to be displaced out of the locking recess 80 against the spring 84 of the pressure piece 76, so that the pressure piece 76 is tensioned in the swivel position shown in FIG. 8c and abuts against the support element 18.

(61) In this way, the pressure piece 76 forms a defined pressure point which, during swivelling of the swivel elements 4, indicates to the user the swivel range in which the transition is taking place of the first pressure piece 22c or of the holding device 20c out of the first switch position A into the second switch position B.

(62) In order to allow a swivelling movement of the swivel elements 4 into the position shown in FIG. 8c and at the same time to keep the distance of the actuating portions 10 as short as possible in the closed state of the swivel elements 4, the actuating portions 10 of the swivel elements 4 overlap in the position shown in FIG. 8c. Due to the overlapping actuating portions 10, a wider swivel range of the swivel elements 4 is provided compared to the embodiments described above. It is thereby also ensured that an opening width of the receiving region 6 which exceeds that which is usual for introducing the components to be pressed can be achieved in order to actuate the holding device 20c.

(63) FIG. 9 is a side view of a fourth embodiment of a pressing tool 2 according to the invention in a closed position. The embodiment shown in FIG. 9 differs from the embodiment shown in FIG. 8 only in that the second pressure piece 76 present in FIG. 8 has been replaced by a second holding device 20c according to the invention. In the embodiment shown in FIG. 9, markings 86 which are provided on the support element 18 and on the swivel element 4 indicate to the user the swivel position in which the transition is taking place of the holding devices 20c from the first switch position A into the second switch position B. If the markings 86 are positioned one directly above the other, the swivel elements 4 of the pressing tool 2 are in a swivel position comparable to FIG. 8b, the holding devices 20c being in the first switch position A.

(64) According to further embodiments of the pressing tool according to the invention, it is also possible to provide only a single holding device to fix the swivel elements in an open position. In this respect, a transmission which couples the movement of the swivel elements can preferably be provided between the swivel elements, so that the swivelling or fixing of one swivel element causes the respective other swivel element to be swivelled or fixed.