Hydraulic tool for a pulling and/or pressing device

Abstract

Hydraulic tool for driving a pulling and/or pressing device, comprising a drive shaft that can be mounted to a screwdriver, wherein the drive shaft is operable to drive a hydraulic pump that pumps hydraulic fluid into the operating chamber of a hydraulic power piston. The hydraulic tool may in particular be configured as a riveting or punching attachment for a cordless screwdriver.

Claims

1. A hydraulic tool for driving a pulling or pressing device, comprising: a hydraulic pump that pumps hydraulic fluid into an operating chamber of a hydraulic power piston; a drive shaft configured to be mounted to a screwdriver and operable to drive the hydraulic pump; and a torque support which is supported on a housing of the screwdriver.

2. The hydraulic tool as in claim 1, wherein the hydraulic pump comprises a pump piston, the pump piston being driven by the drive shaft to reciprocate and pump the hydraulic fluid into the operating chamber of the hydraulic power piston.

3. The hydraulic tool as in claim 2, further comprising a cam that drives the pump piston to reciprocate.

4. The hydraulic tool as in claim 1, wherein the power piston is connected to a coupling for a setting tool or pressing tool attachment.

5. The hydraulic tool as in claim 1, further comprising a hydraulic fluid accumulator which serves as a buffer volume during movement of the power piston.

6. The hydraulic tool as in claim 5, wherein the hydraulic fluid accumulator is arranged behind the power piston and laterally offset from the drive shaft.

7. The hydraulic tool as in claim 6, wherein the accumulator is pressurized by a spring that engages a piston such that in a non-operated state of the hydraulic tool the power piston moves into an end position.

8. The hydraulic tool as in claim 5, further comprising a pressure control valve which allows hydraulic fluid to flow back into the hydraulic fluid accumulator once a predetermined maximum pressure is exceeded.

9. The hydraulic tool as in claim 5, wherein the torque support is mounted to a housing of the hydraulic fluid accumulator.

10. The hydraulic tool as in claim 1, further comprising an operator control that is actuable to feed hydraulic fluid into an operating chamber of the power piston either in front of or behind the power piston.

11. The hydraulic tool as in claim 10, wherein the operator control is coupled to a 5/2-way valve.

12. The hydraulic tool as in claim 10, wherein the operator control is coupled to a control valve and configured such that the control valve has to be actuated permanently in order to advance the power piston.

13. The hydraulic tool as claimed in claim 12, wherein the control valve comprises a rod extending transversely to the power piston, and which serves to open and close passages extending along the rod.

14. The hydraulic tool as in claim 1, wherein the power piston is aligned parallel to the drive shaft.

15. The hydraulic tool as in claim 1, wherein the hydraulic tool is coupled to a screwdriver.

16. The hydraulic tool as in claim 1, wherein an elastic coupling is arranged between the drive shaft and the hydraulic pump.

17. The hydraulic tool as in claim 1, further comprising a chuck lock for the screwdriver.

18. The hydraulic tool as in claim 1, further comprising a drive shaft with a flywheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The subject-matter of the disclosure will be discussed in more detail below with reference to an exemplary embodiment illustrated in the drawings of FIGS. 1 through 28.

(2) FIG. 1 is a perspective view of a hydraulic tool, this view not showing the torque support nor the coupled screwdriver or tool attachment.

(3) FIG. 2 is a top view on the coupling for mounting the tool attachment.

(4) FIG. 3 is a side view and FIG. 4 is a top view of the hydraulic tool.

(5) FIG. 5 is a sectional view along the main extension direction of the hydraulic tool.

(6) FIG. 6 is a sectional view conceived for explaining in more detail the driving of the pump piston.

(7) FIG. 7 is a sectional view of an area including the control valve.

(8) FIGS. 8 and 9 are sectional views intended for explaining the feeding of the hydraulic fluid during pulling and pressing.

(9) FIG. 10 is a detail view of the pressure control valve.

(10) FIG. 11 shows the hydraulic tool coupled to a cordless screwdriver.

(11) FIGS. 12 and 13 are hydraulic equivalent circuit diagrams intended for explaining in more detail two different embodiments of the disclosure.

(12) FIG. 12a is a sectional view taken along line J-J of FIG. 3.

(13) FIGS. 14 to 17 show the hydraulic tool with a riveting yoke as a tool attachment.

(14) FIGS. 18 to 22 show the hydraulic tool with a pulling tool attachment, for example for setting blind rivets.

(15) FIGS. 23 and 24 show an embodiment of a tool with a pulling or pressing device, comprising a torque support which can be coupled to the setting collar for the maximum torque of a cordless screwdriver.

(16) FIG. 25 shows the torque support in a plan view and in a sectional view.

(17) FIGS. 26 to 28 show a further embodiment of a tool according to the invention comprising a pulling or pressing device.

(18) FIG. 26 is a sectional view.

(19) FIGS. 27 and 28 are detail views of FIG. 26.

DETAILED DESCRIPTION

(20) FIG. 1 is a perspective view of a hydraulic tool 1.

(21) Hydraulic tool 1 comprises a housing which can be subdivided into three sections.

(22) Drive piston housing 2 includes the drive piston or power piston and in addition thereto a drive shaft 3 that can be coupled with the chuck of a screwdriver, in particular a cordless screwdriver.

(23) On the side opposite the drive shaft 3, the drive piston housing 2 has a coupling 6 to which a setting tool or pressing tool attachment can be connected.

(24) Laterally, the drive piston housing merges into a hydraulic pump housing 4. The hydraulic pump housing 4 comprises an operator control 7 which can be used to set whether the hydraulic tool 1 pulls or presses.

(25) Furthermore, a pressure control valve is integrated in the hydraulic pump housing in this exemplary embodiment. The control dial 107 coupled to the pressure control valve serves to set the maximum pressure in the operating chamber of the power piston and thus the maximum pulling or pressing force.

(26) An accumulator housing 5 is arranged adjacent to a rear side of the hydraulic pump housing 4.

(27) It has a cylindrical shape and extends backwards laterally offset from the drive shaft 3.

(28) FIG. 2 is a top view of the end face of the hydraulic tool 1.

(29) The coupling 6 can be seen, to which a setting or pressing tool attachment can be fastened, in particular screwed.

(30) Also, it can be seen that the operator control 7 comprises the two opposite actuation means 7a and 7b, which defines a tappet actuation for the control valve described below.

(31) Actuating elements 7a and 7b are connected to one another through a rod 9.

(32) The rod 9 serves to actuate the control valve.

(33) In order to move the power piston forward to perform a pressing operation, the user has to press the actuation means 7a. Without operation of the coupled screwdriver, the power piston will then slowly move forward, by virtue of the pre-pressure in the hydraulic accumulator. If the screwdriver is operated at the same time, high pressure will be applied to the power piston and the actual pressing process will be performed. If, on the other hand, the user presses the actuation means 7b and thus moves the control valve into the position shown here, the power piston will be hydraulically driven so as to move backwards when the screwdriver is operated.

(34) FIG. 3 is a side view of the hydraulic tool 1, and FIG. 4 is a plan view of the top thereof.

(35) FIG. 5 is a sectional view taken along line C-C in FIG. 4.

(36) In this view, the hydraulic tool 1 is cut centrally along its main extension direction.

(37) The drive shaft 3 causes the spring-biased pump piston 15 to reciprocate by virtue of a cam drive 14.

(38) The pump piston 15 extends transversely, in particular perpendicular to the drive shaft 3 and extends from the power piston housing 2 into the hydraulic pump housing 4.

(39) Via a suction valve 16 and a pressure valve 17, the reciprocating piston 15 allows hydraulic fluid to be pumped into the operating chamber 19 of the power piston 20.

(40) The control valve 18 which is connected to the actuation means (7 in FIG. 1) serves to set whether the hydraulic fluid shall flow into the operating chamber 19 in front of or behind the power piston 20.

(41) When moving the pump piston 15 in reciprocating manner through the drive shaft 3, the power piston 20 can thus be used to drive both a pulling tool and a pressing tool.

(42) For this purpose, the power piston 20 is connected to the coupling 6 through piston rod 21.

(43) The hydraulic tool 1 furthermore comprises the hydraulic fluid accumulator 10 which serves as a buffer volume.

(44) The accumulator 10 is pressurized so as to be permanently held under pressure.

(45) For this purpose, a piston 11 is provided in this exemplary embodiment, which is biased by a spring 12 in the accumulator housing.

(46) When the piston 11 is displaced, air can flow out of or into the accumulator housing 5 via passage 13.

(47) The pressure thus prevailing in the hydraulic fluid accumulator 10 ensures that in a non-operated state the power piston 20 moves into a front end position, as illustrated here.

(48) Furthermore, the hydraulic tool comprises a pressure control valve 8 which opens as soon as an adjustable discharge-side maximum pressure is reached and allows hydraulic fluid to flow through passage 22 and into the accumulator 10. Thus, the pressure control valve is at the same time effective as a safety valve.

(49) FIG. 6 is a sectional view taken along line H-H in FIG. 5.

(50) This sectional view is taken perpendicular to the main extension direction of the hydraulic tool 1.

(51) What can be seen is the area around the reciprocating pump piston 15.

(52) In order to move the pump piston 15 in a reciprocating manner, the drive shaft (3 in FIG. 5) is connected to a cam shaft 23.

(53) Fitted to the cam of the cam shaft 23 is a ball bearing or needle roller bearing 24 on which the pump piston 15 sits. For this purpose, the latter may be biased by a spring (not shown). The cam shaft 23 itself is mounted in two ball bearings in this embodiment.

(54) Regardless of the direction of rotation of the coupled screwdriver, the cam shaft 23 will move when the drive shaft rotates and thus, through ball bearing 24, will cause the pump piston 15 to reciprocate.

(55) Thus, with the suction and pressure valves (16 and 17) shown in FIG. 5, the pump piston 15 forms a hydraulic pump.

(56) FIG. 7 is a sectional view taken along line D-D in FIG. 3.

(57) What is shown here is the area of control valve 18 in a sectional view perpendicular to the main extension direction.

(58) The control valve is actuated through rod 9 which is coupled to the operator control 7.

(59) From an accumulation passage 25 which is under pressure in the operated state of the screwdriver, hydraulic fluid can be pumped into different passages through the control valve 18 which is in the form of a 5/2-way valve.

(60) In one setting position, the control valve 18 is switched such that the power piston will move forward due to the pressure in the buffer volume when the screwdriver is not operated. When the screwdriver is operated, the power piston will be moved forward driven by the hydraulic pump.

(61) In the other setting position of the control valve 18, by contrast, the power piston will be moved backwards by the hydraulic pump when the screwdriver is operated, thereby recharging the hydraulic fluid accumulator 10.

(62) In the sectional view of FIG. 8, which shows a section along E-E of FIG. 4, the power piston 20 is in its front end position. If the control valve is set to the advance position for the power piston, the power piston 20 will move into this position due to the pressure prevailing in the hydraulic fluid accumulator.

(63) It can be seen that in order to retract the power piston 20, hydraulic fluid can be pumped via control valve 18 through passages 27 and 26 and into the operating chamber 19 in front of the power piston 20.

(64) In this way, the power piston 20 will be actively retracted by the hydraulic pump and can, for example, drive a blind rivet tool attachment.

(65) FIG. 9, on the other hand, shows a sectional view along F-F of FIG. 4, which illustrates how the control valve 18 is switched when the power piston 20 is advanced by the hydraulic pump.

(66) Through passage 28, the hydraulic pump pumps hydraulic fluid into the operating chamber 19 behind the power piston 20.

(67) According to one embodiment, the actuation means (7 in FIG. 1) has to be actuated permanently for this purpose, in order to ensure two-hand operation upon pressing.

(68) When the screwdriver is operated, the power piston 20 will be moved forward by the hydraulic pump, for example in order to set a rivet or to punch out a hole.

(69) FIG. 10 is a detail view of the area Gin FIG. 5.

(70) Here, the pressure control valve 8 is shown.

(71) When a maximum pressure is exceeded in the hydraulic zone downstream of the pressure valve (17 in FIG. 5), the pressure control valve 8 will open due to the hydraulic pressure applied to passage 31, by causing the spring-biased valve body 29 to be pushed out.

(72) Hydraulic fluid will then flow back into the accumulator (10 in FIG. 5) via passage 30 (and passage 22 shown in FIG. 5). Thus, the hydraulic pump is virtually short-circuited and the pressure in the operating chamber of the power piston is prevented from rising further.

(73) Pressure control valve 8 is designed as a full lift safety valve which opens suddenly once the valve body 29 with needle-shaped front end is lifted, due to the larger cross-section therebehind. This will interrupt the pressing or drawing process. Only after the screwdriver has been switched off, the valve body 29 will be able to return to its initial position against the pressure of the hydraulic accumulator (10).

(74) Valve body 29 is spring-biased, and the opening pressure can be adjusted using the setting means 38 which is driven by the control dial 107 and changes the spring-bias.

(75) FIG. 11 now shows how the hydraulic tool 1 is coupled to a cordless screwdriver 32.

(76) Cordless screwdriver 32 has a handle with an operation button 33.

(77) The drive shaft of the hydraulic tool 1 is clamped in the chuck 34 of the cordless screwdriver.

(78) In this way, a tool combination is provided which the user can grasp by the handle of the cordless screwdriver 32.

(79) In the basic state of the operator control 7, the power piston is completely extended.

(80) For example, if, depending on the embodiment of the hydraulic tool, the user wants to set a rivet or punch out a metal sheet, the user first has to actuate the operator control 7 or bring it into an advance position for the power piston. By pressing the operation button 33 on the cordless screwdriver 32, the power piston is driven forward, together with a setting punch coupled thereto, for example.

(81) Then, depending on the embodiment, the user sets the operator control 7 into the retract position for the power piston.

(82) When the cordless screwdriver is operated, the power piston will then move back and recharge the hydraulic fluid accumulator.

(83) Thus, the device will be ready for the next riveting or pressing process.

(84) When the control valve is actuated into the advance position without operating the cordless screwdriver 32, the power piston will move forward solely by the pressure of the hydraulic fluid accumulator (10). In this way, the setting punch can be slowly approached to the workpiece, for example.

(85) By operating the cordless screwdriver 32, the hydraulic pump is operated and a pressing process is triggered, for example in order to set a rivet.

(86) FIG. 12 shows the hydraulic equivalent circuit diagram according to a first embodiment of the invention. The equivalent circuit diagrams of FIG. 12 and FIG. 13 can be applied to all of the illustrated embodiment variations.

(87) In the embodiment according to FIG. 12, the control valve 18 is configured so as to remain in the respective advance or retract position for the power piston as set by the user.

(88) In the position illustrated here, the control valve 18 is set such that the power piston 20 advances, i.e. moves forward when the hydraulic pump is operated.

(89) Due to the piston rod 21 connected to the power piston 20, the power piston 20 is provided in the form of a differential piston. Thus, the front surface area of the piston is smaller than the rear surface area of the piston.

(90) Consequently, when the power piston 20 is advanced by introducing hydraulic fluid through passage 28 and into the operating chamber 19, less hydraulic fluid will be displaced through passage 26 than is supplied through passage 28.

(91) This differential can be compensated for by the hydraulic fluid accumulator 10 which is biased by spring 12.

(92) In the embodiment illustrated here, the control valve 18 can be set to two switching states and will, as mentioned above, remain in the respective switching position even when the user releases the control valve 18 or an operator control coupled thereto.

(93) In the position of the control valve 18 shown here, when the user does not operate the screwdriver, hydraulic fluid is able to flow through the hydraulic pump 35 which comprises the suction and pressure valves, inter alia. Thus, solely due of the pressure prevailing in the accumulator 10, hydraulic fluid will flow from the accumulator 10 through passage 49 and passage 28 and into the operating chamber 19 behind the power piston 20.

(94) The power piston 20 is thereby advanced, even without operating the screwdriver. In this way, the tool attachment can be approached to the workpiece, for example.

(95) The hydraulic fluid displaced from the operating chamber 19 in front of the power piston 20 flows through passage 26 and via control valve 18 and passage 37 into the accumulator 10.

(96) When the user operates the screwdriver, the hydraulic pump 35 generates pressure and hydraulic fluid inflowing via passage 28 will drive the power piston 20 forward with such a strong force that for instance a riveting or punching process can be triggered.

(97) In order to retract the power piston 20, in particular in order to process a blind rivet, for example, the user moves the control valve 18 into the other position in which the passage 49 is now connected to the passage 26 via the control valve 18.

(98) When the screwdriver is not operated, the hydraulic pressure provided by the accumulator 10 continues to be applied to passage 28. For this purpose, the accumulator 10 is in communication with passage 28 via passage 36 through control valve 18 in this position. However, backflowing of the hydraulic fluid in front of the power piston 20 via passage 26 is blocked by the hydraulic pump 35, specifically by the suction and pressure valves (16 and 17 in FIG. 5) of hydraulic pump 35. Thus, with this retract position of the control valve 18, the power piston 20 will always remain in its position when the screwdriver is not operated.

(99) If the user now operates the screwdriver and thus activates the hydraulic pump 35, fluid will be pressed through passage 26 into the operating chamber 19 in front of the power piston 20 by the hydraulic pump.

(100) The power piston 20 will be retracted. Behind the power piston 20, the displaced hydraulic fluid can flow back into the accumulator 10 through passage 28 and passage 36.

(101) Since the amount of displaced hydraulic fluid is now greater than the amount of introduced hydraulic fluid, the accumulator 10 which is biased by spring 12 will be charged during this retracting process.

(102) The hydraulic equivalent circuit diagram furthermore shows the pressure control valve 8 which is connected between the discharge-side passage 49 of the hydraulic pump 35 on one side and the passage 30 to the accumulator 10.

(103) Pressure control valve 8 is adjustable by control dial 107. So, the maximum operating pressure and hence the achievable operating force can be preset. Control dial 107 is coupled with a thread and allows for a rotary movement about preferably more than 180° and less than 360°, in the present exemplary embodiment about approximately 340°. Thereby, the spring of the valve piston is biased more or less, and the valve opens once a preset pressure is reached. This is illustrated in the sectional view of FIG. 12a which shows a section along line J-J in FIG. 3. The control dial 107 has detent bores 108, in particular with a respective offset of 30° therebetween. A spring-biased locking pin slides over these detent bores 108 so as to allow the operator to perceive the detent positions and hence the pressure levels that can be preset, which may additionally be marked on the outer surface of control dial 107. Stop 109 limits the rotary range of control dial 107.

(104) As can be seen from FIG. 12, when the pressure control valve 8 is triggered, the hydraulic fluid escaping on the discharge side can flow back through passage 30 and into the accumulator 10, and in this way the hydraulic pump 35 is virtually short-circuited.

(105) Since the pressure control valve 8 is designed as a full lift safety valve, as mentioned before, the pressure applied on passage 49 will abruptly fall to almost zero or to the pressure prevailing in the accumulator 10, and thus a setting or pulling process will be stopped.

(106) FIG. 13 is the hydraulic equivalent circuit diagram of an alternative embodiment of the invention in which two-hand operation is required to initiate a pressing process.

(107) For this purpose, passages 26 and 28 are connected differently to the control valve.

(108) In this embodiment, the control valve 18 is configured such that it has to be permanently actuated in order to be brought from the state shown here into the other switching position. For this purpose, control valve 18 is spring-biased by spring 48 in this exemplary embodiment.

(109) In this non-actuated switching state, the pressure prevailing in the accumulator 10 is applied to both passage 26 and passage 28 in operating chamber 19 when the screwdriver is not operated. Since the hydraulic pump 35 blocks backflow through passage 26 in the non-operated state, the power piston 20 will always remain in its position.

(110) When the user now operates the cordless screwdriver, the hydraulic pump 35 presses hydraulic fluid through control valve 18 and passage 26 and into the operating chamber 19 in front of the power piston 20 so that the latter is retracted, for example in order to place a blind rivet.

(111) Thus, for retracting the user only needs to operate the screwdriver. It is not necessary to actuate the control valve 18 at the same time.

(112) In order to trigger a pressing process, by contrast, the control valve 18 has to be permanently pressed into the other switching state, against the bias of the spring 48.

(113) In this other switching state, the power piston 20 will move forward solely by virtue of the pressure prevailing in the hydraulic fluid accumulator 10.

(114) Only when the control valve 18 is actuated, the hydraulic pump 35 will be able to feed hydraulic fluid via the discharge-side passage 49 and through passage 28 to behind the power piston 20. The power piston will be advanced to perform a pressing operation.

(115) The hydraulic fluid displaced in front of the power piston 20 will flow back into the accumulator 10 via passage 26.

(116) FIG. 14 is a side view of a hydraulic tool 1 (without screwdriver), the hydraulic tool 1 now comprising a riveting yoke 39 as a tool attachment.

(117) Riveting yoke 39 is used to process two-piece rivets or punch rivets and comprises a setting punch 40 driven by the power piston and a die 41 opposite thereto.

(118) FIG. 15 is a perspective view of the hydraulic tool 1 shown in FIG. 14.

(119) It can be seen that a handle 42 is mounted to the riveting yoke 39. Handle 42 may not only be used to hold the hydraulic tool 1. Rather, handle 42 can also serve as a torque support. So, the user can support the riveting yoke 39 against the torque of the screwdriver, without need to have the housing of the screwdriver coupled to the rest of the housing of the hydraulic tool. In this embodiment of the invention, the riveting yoke 39 and the housing of the hydraulic tool are preferably secured against rotation in the coupled state.

(120) FIG. 16 is a sectional view of the hydraulic tool 1 shown in FIGS. 14 and 15.

(121) What can be seen in particular here is the setting punch 40 and the die 41 opposite to one another.

(122) The tool attachment in the form of riveting yoke 39 comprises a sleeve 51 which is coupled to the power piston housing 2. Sleeve 51 may in particular be screwed into the coupling 6.

(123) Furthermore, riveting yoke 39 comprises an inner part 52 coupling the setting punch 40 to the piston rod 21 of power piston 20.

(124) Setting punch 40 can thus be pushed forward by the power piston 20.

(125) FIG. 17 is a detail view of the area D in FIG. 16. What can be seen here is the inner part 52 guided in sleeve 51, into which the setting punch 40 is inserted.

(126) FIG. 18 shows how the hydraulic tool 1 comprises a pulling tool attachment 43 which is intended for setting blind rivets, for example.

(127) Pulling tool attachment 43 also comprises a handle 42 which extends transversely to the main extension direction thereof.

(128) FIG. 19 is a side view of the hydraulic tool 1 shown in FIG. 18.

(129) FIG. 20 is a sectional view taken along line E-E in FIG. 19.

(130) Thus the section is cut through the handle 42.

(131) It can be seen that the handle 42 can be released through a release member 44, without tools.

(132) FIG. 21 is a sectional view of the hydraulic tool 1 shown in FIGS. 18 and 19 taken along the main extension direction thereof. Pulling tool attachment 43 comprises the sleeve 51 which is coupled to the power piston housing 2.

(133) Power piston 20 is coupled to the pulling device 45 through piston rod 21.

(134) FIG. 22 is a detail view of the area D in FIG. 21.

(135) In particular the pulling device 45 is shown in this detailed illustration.

(136) It can be seen that pulling device 45 comprises claws 46.

(137) In the state shown here in which the power piston is in its forward or extended position, claws 46 are open.

(138) The user can now insert a blind rivet into the pulling device 45.

(139) When processing the blind rivet, the pulling device 45 bears against the workpiece with its front sleeve 47, in known manner.

(140) During retraction, the claws 46 are contracted by ramps 53 and retain the break-off mandrel of the blind rivet captured until it breaks off at the end of the setting process.

(141) FIG. 23 is a perspective view of a tool 100 comprising a pulling and/or pressing device that can be coupled with a screwdriver, here a cordless screwdriver 32.

(142) In this exemplary embodiment, the tool 100 is a hydraulic tool according to the exemplary embodiments described above. However, the tool 100 may also work according to another principle in this embodiment of the invention.

(143) The tool 100 comprises a housing 102 with a pulling and/or pressing device which is connected to the cordless screwdriver 32 through a drive shaft.

(144) The tool attachment 101 is rotatably connected to the housing 102. In this exemplary embodiment, the tool attachment 101 is designed as a riveting yoke and comprises the handle 42. It goes without saying that the tool attachment 101 may alternatively correspond to the pulling tool attachment described above.

(145) In order to set a rivet, the tool 101 is driven by actuating the operating button 33 of the cordless screwdriver 32.

(146) The housing 102 of tool 100 is connected to the cordless screwdriver 32 through torque support 103.

(147) In this exemplary embodiment, the torque support 103 is fitted around the hydraulic fluid accumulator housing 5.

(148) As can be seen in the side view of FIG. 24, the torque support 103 engages around the torque limit setting collar 104 of the cordless screwdriver 32.

(149) If now a rivet is set, the housing 102 is initially held by the tool attachment 101 which is rotatably coupled to the housing 102. The torque between tool attachment 101 and housing 102, at which rotation between these two components starts to occur can be adjusted, for example using sealing elements such as O-rings.

(150) If now the torque increases, for example towards the end of a setting process, the housing 102 will rotate relative to the tool attachment 101 and thus also relative to the cordless screwdriver 32.

(151) In response thereto, the torque support 103 which engages around the setting collar 104 will cause the torque clutch 103 of the cordless screwdriver 32 to open and the pulling and/or pressing process will be stopped.

(152) FIG. 25 shows the torque support 103 in a plan view and in a sectional view side by side.

(153) In this exemplary embodiment, clamping screw 105 serves to connect the torque support 103 both to the housing of the tool (102 in FIGS. 23/24) and to the setting collar (104) of the cordless screwdriver (32).

(154) The coupling ring 106 for the setting collar is preferably adjustable in its diameter and/or consists of elastic material, at least in sections thereof, to adapt to different cordless screwdrivers.

(155) FIGS. 26 to 28 are views of a further alternative embodiment of a tool 100 comprising a pulling or pressing device.

(156) The tool shown in these drawings substantially corresponds to the exemplary embodiment illustrated in FIGS. 1 through 22, so that primarily the structural differences will be explained below.

(157) FIG. 26 is a sectional view of the tool 100 with a pulling or pressing device.

(158) A housing 102 comprising a hydraulic pump is coupled to a cordless screwdriver 32 through a drive shaft 3.

(159) In contrast to the previously illustrated exemplary embodiments, the torque support 103 engages on the foot 54 of the cordless screwdriver 32 through an arm 110 which is connected to the housing 102. In this way, a longer lever can be provided for support in comparison with the previously described exemplary embodiments.

(160) The width and/or height of the torque support 103 which engages around the foot 54 in a clamp-like manner is preferably adjustable in order to adapt to differently shaped cordless screwdrivers 32.

(161) FIG. 27 is a detail view of the area H in FIG. 26, showing the configuration of the hydraulic pump.

(162) In contrast to the exemplary embodiment illustrated before, the hydraulic pump does not comprise a control valve through which the power piston can be advanced and retracted, but only comprises a relief valve 111 which is a 2/2-way valve in this exemplary embodiment.

(163) When the cordless screwdriver is operated, the driven cam shaft 23 causes hydraulic fluid to be pumped via suction valve 113 and pressure valve 114 from the accumulator 10 through passage 115 and into the operating chamber 19 of the pulling or pressing device.

(164) Once a pulling or pressing process has been completed, the user can actuate the relief valve 111 through an actuation means 112 which may be in the form of a lever, for example.

(165) In this exemplary embodiment, a spring-biased ball opens the relief valve 111 and hydraulic fluid can flow back into the accumulator 10 via passage 115, through relief valve 111, and through passage 116.

(166) The pressure required for this is provided by a spring 12, which resets the power piston of the pulling or pressing device.

(167) FIG. 28 is a detail view of the area I in FIG. 26, which shows the coupling between the screwdriver and the rest of the hydraulic tool.

(168) On the one hand, the cam shaft 23 of pump piston 15 is coupled to the drive shaft 3 via an elastic coupling 117.

(169) Elastic coupling 117 is integrated in the housing and consists of a coupling bell 119 which is connected to the cam shaft 23 through at least one ring 118 made of elastic material.

(170) In this exemplary embodiment, the connection is made by pins 119.

(171) The soft coupling created in this way allows to largely avoid rattling as is in particular caused by the drive shaft recoiling when the pump piston 15 exceeds a dead center.

(172) Furthermore, the drive shaft is provided with a chuck lock 120 which can be used to fix the chuck of the cordless screwdriver (not shown) in order to prevent it from loosening due to vibrations.

(173) The chuck lock 120 comprises a bell 121 which at the same time serves as a flywheel for the drive shaft 3.

(174) A union nut 124 engages around the bell and serves to tighten the chuck lock 120.

(175) In this exemplary embodiment, in order to provide a non-positive connection, the chuck lock 120 comprises a deformable ring 122 which is slotted, for example, and can thus be reduced in diameter when being pressed against an inclined surface by tightening the union nut 124.

(176) In this exemplary embodiment, the deformable ring 122 is secured against rotation relative to the bell 121 by a pin 125.

(177) Furthermore, in this exemplary embodiment, a ring 123 made of elastic material such as an O ring is inserted into the deformable ring 122 in order to improve adhesion to the chuck of the screwdriver.

(178) In order to improve the connection between the drive shaft 3 and the cordless screwdriver, the drive shaft 3 may have positive locking features (not shown) which engage in the chuck of the cordless screwdriver.

LIST OF REFERENCE NUMERALS

(179) 1 Hydraulic tool 2 Power piston housing 3 Drive shaft 4 Hydraulic pump housing 5 Accumulator housing 6 Coupling 7 Operator control 7a, 7b Actuation means 8 Pressure control valve 9 Rod 10 Hydraulic fluid accumulator 11 Piston 12 Spring 13 Passage 14 Cam drive 15 Pump piston 16 Suction valve 17 Pressure valve 18 Control valve 19 Operating chamber 20 Power piston 21 Piston rod 22 Passage 23 Cam shaft 24 Ball bearing 25 Accumulation passage 26 Passage 27 Passage 28 Passage 29 Valve body 30 Passage 31 Passage 32 Cordless screwdriver 33 Operation button 34 Chuck 35 Hydraulic pump 36 Passage 37 Passage 38 Setting means 39 Riveting yoke 40 Setting punch 41 Die 42 Handle 43 Pulling tool attachment 44 Release means 45 Pulling device 46 Claws 47 Sleeve 48 Spring 49 Passage 50 Spring 51 Sleeve 52 Inner part 53 Ramp 54 Foot of screwdriver 100 Tool with pulling and/or pressing device 101 Tool attachment 102 Housing 103 Torque support 104 Setting collar 105 Clamping screw 106 Coupling ring 107 Control dial 108 Detent bore 109 Stop 110 Arm 111 Relief valve 112 Actuation means 113 Suction valve 114 Pressure valve 115 Passage 116 Passage 117 Elastic coupling 118 Ring made of elastic material 119 Coupling bell 120 Chuck lock 121 Bell/flywheel 122 Deformable ring 123 Ring made of elastic material 124 Union nut 125 Pin