EP1979110B1 - Hydraulically driven pressing device, and method of pressing a fitting - Google Patents

Abstract

A method of using a hydraulically driven pressing device for pressing a fitting on a tube is provided. The pressing device includes a piston and a cylinder for acting on pressing jaws. A piston shaft is connected to rollers. The pressing device can be used to carry out pressing operations requiring different levels of pressing power, by using an adjustable stop which is provided in the direction of displacement of the piston in order to achieve different end positions for the piston during the piston return stroke.

Description

The invention relates firstly to a hydraulically driven pressing device having a piston and a cylinder for acting on compression jaws, wherein in any case the piston shaft is connected to action means, according to the preamble of claim 1 and a method for pressing a fitting according to the preamble of claim 9.

Grouting of the type in question are known. For example, on the DE 19803536 A1 directed. In this document, a pressing device is described and shown, which acts via pincer-like jaws on a grouting chain with several chain links. The piston of the pressing device for acting on the compression jaws is hydraulically displaced into the pressing position. The return stroke takes place by means of a tensioned in the course of the forward stroke spring.

From the DE 10010601 A1 is a pressing device of the type in question is known, in which hydraulically acting on a molded from the compression jaws, interchangeable dies bearing press jaw is acted.

In addition, the state of the art on the US 5,253,554 to refer. From this, a pneumatically driven pressing device is known. A threaded adjustable stop protrudes into the pneumatic cylinder. From the DE 202 02 200 U1 a hydraulic pressing device is known in which an adjustable stop is provided, which allows (two) different setting of the hydraulic piston in the piston return.

The action on the compression jaws generally takes place via tool-side action means, which are in any case connected to the piston shaft of the hydraulically displaceable piston.

Starting from a prior art according to the DE-A-19803536 the invention is concerned with the task of further developing a pressing device of the specified type so that different press forces required compressions can be performed in an advantageous action on the hydraulic piston with the same device.

This object is achieved in the subject matter of claim 1, wherein it is pointed out that in the direction of travel of the hydraulic piston, an adjustable stop is provided to achieve different settings of the hydraulic piston in the piston return and that the stop is provided outside the cylinder. As a result, despite the training as a hydraulic device is given an advantageous adjustment. Different piston strokes can be driven. Also by means of the adjustable stop learns the return of the piston, in particular after pressing, a limit, so that a Following Verpressvorgang of this limited piston stop position is carried out According to this stop setting are compressions with different Verpressenergien feasible, this with only a "shot", ie with only one actuation of the device. This is more preferably done with continuously moving piston movement. Accordingly, no idling is preferably provided with regard to the piston stroke. If low compression forces are required, the adjustable stop is moved to a position from which the piston covers a relatively small axial travel for compression. At high required Verpressenergien the stop is brought into a position corresponding to which the piston travels a longer way to final compression. Correspondingly, pressing with different pressing energies can be achieved with one and the same pressing device, wherein in general, ultimately, in conventional pressing devices, the pressing jaw sections cooperating with the action means also result in different pressing forces. But it can also be achieved in spite of different Verpressenergien a same final force in the maximum Verpressstellung. Increased injection energy is required, for example, when pressing fittings with large nominal widths. The proposed solution can continue to be used with the pressing device usual standard compression jaws.

For this purpose, a standard press jaw holder is provided on the pressing device. Namely, preferably one in which the fork legs of the device neck on the mutually facing surfaces, which basically consist of parallel planes, have a central longitudinal groove running in the direction of travel of the piston. The longitudinal groove preferably also has parallel surfaces (groove bottoms). The width of the groove bottom is preferably 36.2 to 36.4 mm. The distance of the groove bases, ie in the direction perpendicular to the surfaces forming the groove bases, is preferably 33.1 to 33.3 mm. Furthermore, the pressing jaws can be secured by a bolt passing through the device necks transversely to the direction of travel of the piston. For this purpose, the pressing jaws on tabs with holes. The diameter of the holes in the tabs or in the device necks is 14 to 14.1 mm, with a bolt diameter of 13.5 to 13.95 mm.

It is understood that the dimensions mentioned, as long as the compatibility with regard to matching standard jaws is given, may vary somewhat.

It is essential that both the pressing jaws for pressing with high energy as well as the standard compression jaws in one and the same press jaw recording, just the standard press jaw recording described, can be used and secured.

The adjustment of the stop can be done mechanically, such as hydraulically or electrically assisted. Preferred is an embodiment in which the stop is adjustable by hand, this more preferably under solution a rest or the like from a displacement, in particular sliding shift. In a further preferred embodiment, the adjustable stop is provided with two stop positions which can be locked in particular. It is quite possible, the stop also with multiple positions, that is to provide the two end positions and other intermediate positions, so as to expand the range of possible piston strokes and according to the Verpressenergien. It is further proposed that the stop is adjustable by means of a handle provided radially outside of the cylinder. The handle is accordingly provided in the so-called dry area of the hydraulic system, that is to say radially outside the cylinder enclosing the hydraulically operated piston. Thus, the handle is preferably arranged in a handling-technically favorable position on the pressing device, more preferably in a local bypass to the pressing jaws. The handle is preferably designed as a sleeve displaceable relative to the cylinder, so more preferably as a sleeve comprising the cylinder, which can be enclosed by the user if necessary. This sleeve-shaped handle is provided for example with a detent button, to cancel the locking positions locking locking or the like. On the cylinder on which the sleeve is displaceable, markings or the like, so on, for example, colored markers can be provided, which clarified the different stop positions.

The stop provided outside the cylinder, further in the so-called dry area beyond the hydraulic loading of the piston. In this case, the stop preferably interacts with a section of the piston shaft connecting the piston with the action means. The piston cooperating with the stop does not necessarily have to be the piston of the hydraulic cylinder-piston combination. Rather, an arrangement is conceivable in which the pressing device has a replacement head with a separate piston stem and return spring. Accordingly, in such an embodiment, the stop together with the handle part of the interchangeable device head, which is adjustable according to different required Verpressenergien according to this embodiment.

The impact means connected to the piston shaft are rollers which act on facing cam tracks of the pressing lever or Verpressbacken to cause over the piston stroke spreading of the cam tracks having Verpressbackenenden, which at the other end of the Verpressbacken closing the molding mouth formed there result. In a preferred embodiment, the stop cooperates with these rollers. The latter drive accordingly in the course of the piston return after pressing against the stop, from which position out of the next grouting process can be performed.

It is also provided that the pressing device is equipped with at least two pairs of different compression jaws, which differ in the length of a cooperation region - the curved path - with the action means, with a longer range of cooperation associated with a lower slope angle of the action means associated surfaces of the cooperation areas. Accordingly, the pressing device is to be equipped with pairs of compression jaws, which differ in the same Pressmaulgeometrie particular by the length of cooperating with the action means or rollers cheek presses, this adapted to the adjustable stroke via the adjustable piston stroke. By adjusting the angle of increase of the cooperating with the rollers cam tracks of the compression jaws a change in the injection energy is achieved at preferably constant thrust of the piston of, for example, 32 kN. Accordingly, for example, for pressing fittings with larger diameters and in this case preferably desired higher Verpressenergien Verpressbacken fixed with longer pressing jaw levers on the pressing device and the stop for the piston adjusted so that an enlarged, preferably a maximum piston stroke is achieved. By compared to the shorter jaws preferably over the entire piston stroke shallow angle of attack cooperating with the rollers cam tracks is an increase in the injection energy, preferably achievable with constant piston thrust, resulting in general, also different compression forces in the press jaw. Despite different Verpressenergien a constant final force in the press jaw can be achieved.

The preferred stop-limited minimum piston stroke is, for example, 40 mm. The maximum piston stroke preferably corresponds to 1.5 to 3 times the minimum stroke, eg. 80 to 100 mm. With a preferably constant piston thrust of approximately 32 kN, injection energies of 1000 to 4000 joules can be achieved, such as, for example, 1280 joules for a short-stroke compression and 3040 joules for a long-stroke compression (theoretical values before losses).

The invention further relates to a method for pressing a fitting with a pipe by means of a Verpresskette and, having a piston and a cylinder having hydraulic Verpressgerät, wherein the Verpresskette has more than two chain links and the pressing is carried out with a certain injection energy, according to the subject matter of claim 9.

A Verpresskette is from the DE 10257613 A1 known. This is operated for example by means of a pressing device, for example according to the DE 19944229 A1 ,

In order to improve a method of the type in question, it is proposed that the pressing is carried out with a pressing device, the pressing energy applied in the course of a compression by changing an outside of the cylinder provided fixed stop, against which the piston anfährt to limit the piston movement, changeable and is set for a certain compression so that the compression is carried out in the course of a continuous piston movement.

According to the proposed method, the same pressing device can be used both for pressing fittings with low pressing energy and for pressing fittings with higher injection energy. There are, according to the pressing device different piston strokes available, which are completely traversed by the piston after a single operation of the device (in a "shot"). By means of the adjustable fixed stop learns the return of the piston, in particular after pressing, but possibly also by user-side engagement a limit, so that a subsequent pressing operation of this limited piston stop position takes place. If low compression forces are required, the adjustable stop is moved to a position from which the piston covers a relatively small axial travel for compression. At high required Verpressenergien the stop is brought into a position corresponding to which the piston travels a longer way to final compression. Regardless of the variably adjustable via the variable fixed stop pressing forces and concomitant different piston strokes, the piston thrust force is preferably the same size. This can quite generally result in different compression forces in the press jaw. Increased injection energy is required, for example, when pressing fittings with large nominal widths.

Fig. 1

in perspektivischer Darstellung ein Verpressgerät in einer ersten Ausführungsform mit auf eine Verpresskette einwirkenden Verpressbacken;

Fig. 2

den Schnitt gemäß der Linie II - II in Fig. 1, eine Langhubstellung des Werkzeuges betreffend;

Fig. 3

den Auswechsel-Gerätekopf des Verpressgerätes in Einzeldarstellung, gleichfalls die Langhubstellung betreffend;

Fig. 4

den Schnitt gemäß der Linie IV - IV in Fig. 3;

Fig. 5

den Schnitt gemäß der Linie V - V in Fig. 3;

Fig. 6

die Stirnansicht gegen den Auswechsel-Gerätekopf;

Fig. 7

eine der Fig. 3 entsprechende Darstellung, jedoch eine Zwischenstellung im Zuge der Verlagerung eines Anschlags betreffend;

Fig. 8

den Schnitt gemäß der Linie VIII - VIII in Fig. 7;

Fig. 9

den Schnitt gemäß der Linie IX - IX in Fig. 7;

Fig. 10

eine der Fig. 3 entsprechende Darstellung, jedoch die Kurzhubstellung betreffend nach Verlagerung des Anschlags;

Fig. 11

den Schnitt gemäß der Linie XI - XI in Fig. 10;

Fig. 12

den Längsschnitt durch das Verpressgerät in der Langhubstellung mit entsprechenden längeren Verpressbacken zur Einwirkung auf eine Presskette;

Fig. 13

eine der Fig. 12 entsprechende Darstellung, jedoch die Kurzhubstellung mit kürzeren Verpressbacken betreffend;

Fig. 14

die längeren Verpressbacken in Einzeldarstellung;

Fig. 15

die kürzeren Verpressbacken in Einzeldarstellung;

Fig. 16

eine Vergleichsdarstellung von längerer und kürzerer Verpressbacke;

Fig. 17

eine perspektivische Darstellung eines Verpressgerätes gemäß der Darstellung in Fig. 1, jedoch eine zweite Ausführungsform betreffend mit ein Verpressmaul ausformenden Verpressbacken;

Fig. 18

in einer weiteren Ausführungsform eine perspektivische Darstellung eines handbetriebenen, hydraulisch wirkenden Verpressgerätes mit einem verstellbaren Anschlag;

Fig. 19

eine perspektivische Darstellung des Verpressgerätes in einer weiteren Ausführungsform.

Below, the invention with reference to the accompanying drawings, which illustrates only exemplary embodiments, explained in more detail. It shows:

Fig. 1

in a perspective view of a pressing device in a first embodiment with acting on a Verpresskette compression jaws;

Fig. 2

the section according to the line II - II in Fig. 1 concerning a long-stroke position of the tool;

Fig. 3

the replacement device head of the pressing device in a single view, also concerning the long stroke position;

Fig. 4

the section according to the line IV - IV in Fig. 3 ;

Fig. 5

the section along the line V - V in Fig. 3 ;

Fig. 6

the front view against the replacement head;

Fig. 7

one of the Fig. 3 corresponding representation, but an intermediate position in the course of the relocation of an attack concerning;

Fig. 8

the section according to the line VIII - VIII in Fig. 7 ;

Fig. 9

the section according to the line IX - IX in Fig. 7 ;

Fig. 10

one of the Fig. 3 corresponding representation, but concerning the short-stroke position after displacement of the attack;

Fig. 11

the section according to the line XI - XI in Fig. 10 ;

Fig. 12

the longitudinal section through the pressing device in the long stroke position with corresponding longer compression jaws for acting on a compression chain;

Fig. 13

one of the Fig. 12 corresponding representation, but concerning the short-stroke position with shorter compression jaws;

Fig. 14

the longer compression jaws in single representation;

Fig. 15

the shorter compression jaws in individual representation;

Fig. 16

a comparison of longer and shorter compression jaw;

Fig. 17

a perspective view of a Verpressgerätes as shown in FIG Fig. 1 but a second embodiment relating to a compression jaw forming compression jaws;

Fig. 18

in a further embodiment, a perspective view of a hand-operated, hydraulically acting pressing device with an adjustable stop;

Fig. 19

a perspective view of the pressing device in a further embodiment.

Shown and described is first with reference to FIG. 1 a first embodiment of an electric motor operated, hydraulic pressing device 1. Such a tool is from the DE 19944229 A1 known. The content of this patent application is hereby incorporated in full in the disclosure Also included for the purpose of incorporating features of this patent application in claims of the present invention.

In the device 1, an electric motor is arranged. The drive of this electric motor via a, integrated in a handle 2 accumulator. Upon actuation of a finger-operable switch in the region of the handle 2, oil is pumped from a reservoir into a cylinder 4, whereby a piston 5 is moved in the direction of its working end position.

On the hydraulic cylinder 4, which includes the piston 5 provided with a radial seal 6, a replaceable device head 7 is arranged in the illustrated embodiment. This device head 7 shown in the illustrations serves to receive pressing jaws 8 to be acted upon.

The substantially cup-shaped hydraulic cylinder 4 is the device head 7 facing open formed and serves on the one hand inside the leadership of the piston 5 and the other outside to connect the Verpressgerätes 1 with the device head 7, to which the hydraulic cylinder 4 externally has an external thread 9.

The piston 5 is cup-shaped, with a coaxially aligned pot wall 10, which is supported on the inner wall of the hydraulic cylinder 4 on the outside wall.

The cup wall 10 comprises a seated on the piston 5 piston skirt 11 at a radial distance, which piston shaft 11 at the other end carrier is the interaction with the Verpressbacken serving action means 12. These are formed as rollers 13.

There are two such rollers 13 provided on a shaft-end side support 14. The rollers 13 are rotatably supported on the carrier 14, wherein the arrangement is further selected so that the rollers 13 are arranged in juxtaposition on both sides of a piston shaft longitudinal axis x.

The device head 7 is fixedly connected to the pressing device 1 by means of a cylinder section 15, which is provided with an internal thread 16 for cooperation with the external thread 9. The cylinder portion 15 radially outwardly forms a stop wall 17, which is penetrated by the piston skirt 11. The stop wall 17 serves to support the one end of the piston shaft 11 comprehensive cylinder compression spring 18, the other end, comprises of the pot wall 10, via a piston shaft-side centering projection 19 acts on the piston 5. The centering projection 19 is seated in a facing recess of the piston 5 a.

In the illustrated embodiments, the action means 12 act on compression jaws 8, which serve to press a fitting by means of a Verpresskette. It comes in this regard in particular a compression chain used, as they are known from DE 10257613 A1 is known. The content of this patent application is hereby also incorporated in full in the disclosure of the present invention, also for the purpose of including features of this patent application in claims of the present invention.

The injection chain 20 has a total of four pressing members 21, which are involved in cooperation in the pressing process.

The action of the compression jaws 8 on the Verpresskette 20 via chain-side articulated lever 22. These are equipped with force introduction elements 23 in the form of bolts. These bolts form bearing and abutment for acting on the Verpresskette 20.

The compression jaws 8 are replaceably mounted on the device head 7. For this purpose, the latter has a device neck 24. This is fork-shaped, with a transverse to the neck extension the fork legs passing through bolt receptacle in which a locking bolt 25 is supported.

The locking pin 25 passes through the device side of the fork legs of the device neck 24 and on the tool side correspondingly positioned fixing openings 26, which are formed in fastening straps 27.

The fastening tabs 27 dive into the fork region of the device neck 24 with their sections having the fastening openings 26.

The fastening tabs 27 are T-shaped in plan, wherein the central T-leg has the above-described fixing opening 26 and the transverse thereto aligned T-webs each receiving holes 28 have.

Between the two attachment tabs 27, the compression jaws 8 are pivotally supported, including on both sides in the receiving holes 28 of the attachment tabs 27-mounted pivot pin 29 enforce the compression jaws 8.

The pivot axes extend on both sides perpendicular to the piston shaft longitudinal axis x.

With regard to the parts of the device neck 24 designed for holding the compression jaws 8 and the corresponding adapter parts on the compression jaws, that is to say in particular the fastening straps 27 mentioned, the compression jaws are designed according to a standard.

For this purpose, it is provided in detail that the fork arms 24 'and 24 "of the equipment neck 24 have two mutually parallel planes E and E', which in turn symmetrically (as well as the planes E and E 'itself) to a transverse axis yy (see. Fig. 6 ) in cross-section recessed longitudinal grooves 46, 46 ', with groove bottoms, which in turn have substantially mutually parallel opposing surfaces. The transverse spacing of the groove bases t is in this case preferably 33.1 to 33.3 mm for the selected standard design. The width b of the grooves 46, 46 'is preferably 36.2 to 36.4 mm.

The compression jaws are secured in the receptacle by means of one of the fork legs 24 'and 24 "passing through bolt 25, which also the fixing openings 26 in the fastening tabs 27 (see also Fig. 12 ) interspersed.

The bolt has this in the selected standard training a diameter of 13.5 to 13.95 mm, while said holes have a diameter of 14 to 14.1 mm.

The compression jaws 8 are formed in a lever-like manner and aligned like a pliers because of the articulation described above on the attachment tabs 27, wherein a lever portion of each compression jaw 8 forms a control lever 30 and the extension of this control lever 30 over the region of the fastening tabs 27 projecting portion a pliers jaw-like Einwirkabschnitt 31. These are provided with adapted receptacles for the force introduction elements 23 of the injection chain 20, so for example with these bolts receiving holes or open-edged recesses.

The control lever 30 extending from the mounting tabs 27 in the direction of the device-side action means 12 and form this facing, that is on the narrow sides facing each other curved Control surfaces 32, along which run the roller-shaped engagement means 12 in the course of a Kolbenvorverlagerung.

Upon actuation of the pressing device 1 oil is pumped into a pressure chamber, whereby the piston 5 against the action of the return spring 18 in the direction of its working end position, that is moved in the direction of the compression jaws 8.

Here, the action means 12 or rollers 13 passing against the control surfaces 32 of the compression jaws 8 bring about a pivoting of the control lever sections 30 of the compression jaws 8 caused by the selected angle of rise of the control surfaces, and consequently the end-side action sections 31 of the compression jaws 8 are moved toward each other via the pivot axes. By means of the articulated levers 22, this causes the Verpresskette 20 to close, and consequently a compression of a fitting by means of the pressing members 21.

The return movement of the piston 5 via the return spring 18, as soon as an unillustrated return valve opens due to the exceeding of a predetermined maximum pressure. In this regard is on the DE 19825160 A1 directed. The content of this patent application is hereby also incorporated in full in the disclosure of the present invention, also for the purpose of including features of this patent application in claims of the present invention.

The opening of the outlet valve is carried out automatically when a maximum pressure on the fitting is exceeded, after which the piston 5 is initially driven back automatically by pressure spring. The exhaust valve closes automatically as soon as the pressure on the oil caused by the returning piston 5 drops due to piston stop.

After a successful compression of the piston moves due to the valve opening and the resulting pressure drop on the part of the hydraulic spring assisted back to a piston-rest position, which is reached limited stop.

Starting from this piston rest position, the piston 5 moves on renewed activation over a predefined distance until reaching or exceeding the maximum pressure. With a constant piston thrust of preferably 32 kN can be varied by changing this distance, the applied pressing energy.

For this purpose, the piston rest position defining stop is adjustable, according to which the distance is adjustable to the desired injection energy changeable.

Outside the hydraulic range, that is, on the dry side of the piston 5, specifically in the illustrated embodiment in the region of the removable device head 7, an adjustable stop 33 is provided. This is the inner wall of a cylinder portion 15 of the removable device head 7 comprehensive sleeve 34 is formed.

This sleeve 34 is slidably mounted in axis extension of the piston shaft 11 on the cylinder portion 15, wherein the axial displacement of the sleeve 34 is stop-limited in both directions, which define both stop-limited end positions at the same time the two positions for the adjustable stop 33.

The simultaneously formed as a handle 35 sleeve 34 has a, preferably thumb-actuable push button 36. This is acted on the underside by a compression spring 37 radially outward.

The push button 36 is accommodated in an inner wall of the sleeve 34 arranged on this stop housing 38, on the receiving bottom for the push button 36, the compression spring 37 is supported.

The acting in the stopper housing 38 effective portion of the push button 36 has a radially enlarged collar 39. This acts on in a plane transverse to the extension of the longitudinal axis on both sides of the push button 36 arranged locking balls 40, which pushed over the collar 39 to the outside in correspondingly positioned detent ball recordings 41 of the device head side cylinder portion 15 occur. This latching engagement forms the aforementioned, definable end stop for the sleeve 34th

In the illustrated embodiment, two positions of the sleeve 34 can be locked in place, so on the one hand viewed in the axial direction of the rear position shown in the figures in the FIGS. 2 to 5 and a front position as shown in FIGS. 10 and 11.

The FIGS. 7 to 9 show a non-latching intermediate position of the sleeve 34th

The pointing in the direction of the action means 12 end face 42 of the stop housing 38 forms the adjustable stop 33 from.

In a longer piston stroke a generating rear detent position of the sleeve 34, the piston 5 occurs in a conventional manner in the piston rest position against the bottom of the piston 5 receiving hydraulic cylinder 4 stop limiting at. From this position in accordance with FIGS. 2 to 6 out the piston 5 moves over its maximum travel while applying a maximum injection energy of about 2500 to 3200 joules. According to the rear stop position of the piston 5 and the cooperating via the piston shaft 11 with the piston 5 acting means 12 are held in a rear position. Correspondingly, compression jaws 8 are to be used in such a configuration and are adapted to the variably adjustable distance dimension between the press jaw fixing in the area of the device-side locking bolt and the action means 12 with respect to the length of the control lever 30 via the adjustable stop 33. Thus, in a long piston stroke configuration, compression jaws are as shown in FIG FIG. 12 provided, which opposite the compression jaws 8 'in FIG. 13 have extended control lever 30 with correspondingly longer control surfaces 32.

If no high compression energies are required (for example 1000 to 1500 joules), then the piston rest position is advanced in the direction of the piston advance movement, according to which the piston stroke a 'is shortened in the course of a compression process. For this purpose, the adjustable stop 33 is advanced via the sleeve 34 after previous release of the detent via the push button 36 in the piston advancing direction. This until the corresponding end position in which the intended rest engages again.

This sleeve advancement for adjusting the stop 33 in the short-stroke position is preferably carried out in the course of a previously performed Verpressvorganges or in the course of a corresponding piston forward displacement to thereby provide a corresponding flow of the action means 12 before the stop 33 to be adjusted. Such an intermediate position is for example in FIG. 9 shown, although here without connection of the device head 7 to the pressing device 1. The intermediate position shown is only below Influencing the piston shaft reachable via the piston-cylinder hydraulic system.

In the in the Figures 10 and 11 one of the action means 12 or one of the rollers 13 occurs in the piston return movement after exceeding a maximum pressure or optionally controlled by the user against the end face 42 of the stop housing 38, according to which via the carrier 14 and the piston shaft 11th a standstill is achieved against the action of the force acting on the centering projection 19 of the piston skirt 11 force of the compression spring 18. As a result of this standstill, the pressure in the hydraulic chamber of the hydraulic cylinder in front of the piston 5 drops, resulting in a closing of the exhaust valve.

In this front end position of the piston 5 or the action means 12, the piston stroke corresponds approximately to half the piston stroke in the long-stroke position, for example 40 mm at a long stroke of about 80 mm.

Although the adjustable stop 33 is shown with the sleeve 34 in the illustrated embodiments in the range of a removable device head 7, the proposed solution is quite predictable on Verpressgeräten 1, the device head is not detachably connected to the tool.

Such an arrangement with an adjustable stop 33 for varying the piston stroke at other Verpressvorsätzen than the Verpresskette shown can be used 20, for example, in Verpressbacken 8 "as shown in FIG FIG. 17 , the other end of the control lever 30 form a press jaw 43, optionally for receiving replaceable press inserts.

Also, the proposed arrangement on a hand press device as shown in FIG FIG. 18 be provided, which as a lever-operated implement is trained. The pressure required for the displacement of the piston 5 is therefore not electromotive, but manually operated via a pump lever 44.

Furthermore, there is the possibility of the proposed arrangement on a pressing device 1 as shown in FIG FIG. 19 , which is equipped as a one-hand-operated device, with a one-hand to comprehensive handle portion 45, in which an electric motor for hydraulic pressurization is provided.

The provided with different length control levers 30 compression jaws 8 and 8 'are in the Figures 14 and 15 shown in individual representations. FIG. 16 shows a representation in which the different jaws are drawn to illustrate the control lever side differences in superimposition, wherein the shorter control lever 30 having pressing jaws 8 'are shown in dash-dotted line style.

In the FIG. 14 shown compression jaws 8 for acting by the long-stroke position starting action means 12 are each provided with a control surface exposure length 1, which are adapted to the extended piston stroke.

The corresponding length 1 'of the injection molding jaws 8' designed for shorter piston stroke application corresponds to approximately half of the dimension 1 of the longer compression jaws 8.

As further from the representation in FIG. 16 can be seen, both Verpressbackenpaare 8 and 8 'Einwirkungsabschnittseitig the same design, correspondingly have the same opening angle α in the rest position.

The control surfaces 32 of the control lever 30 are different in terms of their angle of attack in cooperation with the action means 12. Thus, the control surfaces 32 of the elongated compression jaws 8 are convexly curved in plan, with a starting from the free end of each control lever 30 in the course of the further course of the control surface 32 decreasing radius.

Accordingly, by applying by means of the action means 12 initially a relatively steep angle of attack for spreading the compression jaws 8 is reached, which greatly reduces in the course of further piston advance and corresponding action of the rollers 13 on the control surfaces 32 due to the concave configuration of the control surfaces 32.

This angle of attack is set steeper over the entire action path in the case of the shorter-shaped compression jaws 8 'in comparison to the longer compression jaws 8-with the exception of the contact surfaces formed in the region of the free ends of the control levers 30. In the rest position of the compression jaws 8 'as shown in FIG FIG. 15 In the plan view, the control surfaces 32 or, with the exception of the end-side approach surfaces, their control edges run almost parallel, optionally with a tendency to have a wedge-shaped inlet in the direction of the action sections 31.

Due to the different angles of incidence of the control surfaces 32 different, acting on the fitting to be compressed Verpressenergien can be applied with constant piston thrust. The hereby adjusting pressing forces in the press jaw can be different, so with longer stroke sizes.

Also, if necessary, in addition to Kolbenhubänderung a change in the piston thrust force can be made, so for example. By adjusting the trigger point of the spring-loaded hydraulic return valve.

Claims (9)

1. Hydraulically driven pressing device (1) comprising a piston (5) and a cylinder (4) for acting on pressing jaws (8, 8', 8"), at least the piston shank (11) being connected to means of action (12), characterized in that an adjustable stop (33) is provided in the displacement direction of the hydraulic piston (5) in order for different end positions of the hydraulic piston (5) to be reached during the return movement of the piston and that the stop (33) is provided outside the cylinder (4).
2. Pressing device according to Claim 1, characterized in that the stop (33) can be adjusted by hand.
3. Pressing device according to Claim 2, characterized in that the stop (33) can be adjusted by means of a handgrip provided radially outside of the cylinder (4).
4. Pressing device according to Claim 3, characterized in that the handgrip (35) is formed as a sleeve (34) which can be displaced relative to the cylinder (4).
5. Pressing device according to one of the preceding claims, characterized in that the stop (33) can be arrested on the cylinder wall as a fixed part.
6. Pressing device according to one of the preceding claims, characterized in that the means of action are rollers (13).
7. Pressing device according to Claim 6, characterized in that the stop (33) interacts with the rollers (13).
8. Pressing device according to one of the preceding claims, characterized in that the pressing device (1) is provided with at least two pairs of different pressing jaws (8, 8') which differ in respect of the length (1, 1') of a region of interaction with the means of action (12), a relatively long region of interaction being accompanied by a relatively small angle of slope of that surface of the region of interaction which is associated with the means of action (12).
9. Method of pressing a fitting on a tube by means of a pressing chain (20) and a hydraulic pressing device (1) with a piston (5) and a cylinder (4), the pressing chain (20) having more than two chain links (21) and the pressing operation being carried out with a certain level of pressing energy, characterized in that the pressing operation is carried out by a pressing device (1) for which the level of pressing energy applied during a pressing operation can be changed by adjustment of a fixed stop (33) provided outside the cylinder (4), against which the piston (5) strikes in order to limit the piston movement, and is set for a certain pressing operation such that the pressing operation is carried out during continuous ongoing piston movement.

Images