EP2172308A2 - Roller holder unit - Google Patents

Abstract

The holder unit has clamping forceps with clamping jaws, which are connected with a fork-like receptacle (55) in a piston-cylinder unit (50) by retaining bolts. Rollers (2) roll on the jaws while the forceps are moved by the piston-cylinder unit. A lateral fixing plate is arranged at a bearing block (1). The rollers are free-rotatably retained by locking pins. The rollers are contacted along a contact line (B) at an outer circumference in a region between the pins. A dirt collecting chamber (71) includes bearing surfaces and the contact line in a region between contact surfaces of the rollers.

Description

The invention relates to a roller holder unit for a pressing tool according to the preamble of the independent claim.

From the DE-196'31'019 For example, a pressing apparatus is known which comprises pressing tongs for connecting a pipe to a press fitting. The pressing tongs comprise two pivoting arms, which are articulated by means of one pin each pivotally between two identical T-shaped support plates. A piston-cylinder unit is operatively connected to a roller holder comprising two rollers. The pivot arms are provided at one end with a rolling surface for the system on the pressing cylinder of the pressing device. At the opposite end, they are designed as jaws with mutually facing pressing surfaces. The linkages for the bolts are located on the carrier plates at a distance. In the region of the free end of the T-shaped support plates is a receptacle of a connecting pin for connection to the pressing device. When using this device, the pressing tongs are now pulled back to the pressing device. The swivel arms slide with their rolling surfaces along the pressing device to the rear. The tensile force is transmitted via the connecting bolt on the T-shaped support plates. As a result, the pivot arms pivot about the bearing pins, and the pressing jaws are moved against each other and compressed.

From the EP-1'103'349 is an electrically operated pressing tool known which actuates a hydraulic piston-cylinder unit by means of an electrically operated hydraulic pump. This is operatively connected to a roll holder, which comprises two rollers. The jaws are connected by a T-shaped suspension via a retaining bolt with a fork-shaped receptacle. The fork-shaped receptacle is part of the piston-cylinder unit. The rollers on the roll holder roll on the jaws of a pair of pliers as soon as the clamping pliers pulled backwards by the piston-cylinder unit and thus the clamping is completed. The clamping forceps are pressed together by pushing apart the jaws at the back through the rollers. In this embodiment, the roll holder in the form of a yoke, which is firmly connected to the piston rod. Roller holder, rollers and roller bearings must be made very solid, since the whole pressing force and the operating force of the piston-cylinder unit must be taken when rolling the rollers on the jaws of the roles of their storage and transferred to the roll holder. This embodiment of the roller holder requires a corresponding size and dimensioning of the holding plates and the rollers, roller bearings and bearing pins. It is therefore difficult and expensive to manufacture.

The EP-1 684 948 shows finally a roller holder unit for an electrically operated pressing tool, in which a bearing block for two identical rollers is provided with sliding bearing surfaces which correspond in shape to the rolling surface and thus the outer diameter of the roller. This construction has the disadvantage that in the area of the sliding bearing surfaces and attach dirt between the rollers, which lead after some time to blockage and thereby cause jamming.

The object of the invention is to produce a roller holder unit which no longer has these disadvantages. It must be easy to manufacture, lightweight, space-saving and reliable.
This object is achieved by the invention according to independent claim.

An advantage of the invention is that the roll holder unit according to the invention ensures a high degree of blockage freedom. This is achieved by the introduction of a dirt collecting space. This dirt collecting space is influenced in shape and size also by the shape of the sliding bearing surfaces.

An additional advantage of the invention is that the susceptibility to blockages by a scraper is further reduced.

Another advantage of the invention is that it is achieved by screwing the retaining plate with the bearing block in the axial direction that in two-part design of bearing block and plain bearing surfaces, the latter are simultaneously screwed. One saves in this case thus further fasteners.

Figur 1

eine Presszange in Ansicht;

Figur 2

eine 3D-Ansicht einer Kolben-Zylindereinheit;

Figur 3

die Kolben-Zylindereinheit im Schnitt mit der neuen Rollenhaltereinheit;

Figur 4

die neue Rollenhaltereinheit in einer 3D-Ansicht, und

Figur 5

Die neue Rollenhaltereinheit mit dem Lagerbock in einer Explosionsdarstellung.

The invention will be described below in conjunction with the drawings. Show it:

FIG. 1

a pressing tongs in view;

FIG. 2

a 3D view of a piston-cylinder unit;

FIG. 3

the piston-cylinder unit in section with the new roller holder unit;

FIG. 4

the new roll holder unit in a 3D view, and

FIG. 5

The new roller holder unit with the bearing block in an exploded view.

A pressing tool according to the prior art is in FIG. 1 shown. It comprises a drive unit 70, a piston-cylinder unit 5 with a fork-shaped receptacle 55 and the actual clamping pliers 60. The clamping pliers 60 are fastened to a T-shaped holder, which is connected to a retaining bolt 61 and a retaining bolt receptacle with the fork-shaped receptacle 55. In the fork-shaped receptacle 55 is a roll holder with two rollers. The fork-shaped receptacle 55 is part of the piston-cylinder unit 5. The rollers roll on the rolling edges 63 of the jaws 62 of a clamping pliers 60 as soon as the piston rod is pushed forward. In this case, the clamping jaw 60 is compressed by the clamping jaws 62 are pushed apart at the rear by the rollers. The clamping is completed.

The connection of drive unit 70 and clamping tongs 60 is formed by the piston-cylinder unit 5. She insists FIG. 2 from the cylinder head 51 with a through hole for receiving a retaining bolt 54 for the attachment of Clamping pliers 60. In the cylinder head is a compression spring 57, which pushes a piston rod 52 in a rest position forward. In the fork-shaped receptacle 55, one of the rollers 2 is partially visible. When pressing the pressing tool, the piston rod 52 is pushed forward. The cylinder head 51 remains stationary, causing the rollers 2 within the fork-shaped receptacle 55 move relatively forward. The pressing jaws 62 protrude somewhat into the fork-shaped receptacle 55 and, with their rolling flanks 63, bear against the rollers 2 on the outside. The rollers 2 thus run on the pressing jaws 62 along the rolling edges 63 and push them outwards. The pressing is carried out in the clamping tongs 60.

More details of the piston-cylinder unit 5 are made FIG. 3 , shown in section, in connection with the roller holder unit. The piston rod 52 projects on one side into the cylinder head 51. It is biased by a compression spring 57. The compression spring 57 comprises the piston rod 52 and is at one end to a spring pressure washer 53 and at the other end to a seal retaining ring 50 in abutment. The spring pressure washer 53 is fastened to the piston rod 52 with a screw. Between seal retaining ring 50 and cylinder head 51, a scraper ring 59 is arranged, which is pierced by the piston rod 52. At the head end of the piston rod 52, the roller holder unit is attached. It protrudes from the cylinder head 51 in the region of the fork-shaped exception 55 in such a way that two rollers 2 are partially in the fork opening. A bearing block 1 of the roller holder unit is fixed by means of a clamping pin 58 on the piston rod 52. Now, when pressing the pressing tool, the piston rod 52 in an axial direction R is pushed forward, with the cylinder head 51 and the clamping jaw 60 remain stationary, the roller holder unit is moved within the fork-shaped receptacle 55 against the retaining pin 54 and thus against the jaws 62. The rollers 2 thus roll along the rolling edges 63 of the clamping jaws 62 and push them apart. Once the compression is done, the piston rod 52 is moved by the compression spring 57 back to the rest position. Thus, the roller holder unit returns to the rest position just outside the cylinder head 51st

The roll holder unit is in FIG. 4 shown in a 3D view. It consists of a bearing block 1, which corresponds to a cylindrical recess in the cylinder head 51, on the front-outer side. Perpendicular to the bearing block 1, a holding plate 3 is present. It is by means of screws 4 (see Fig. 5 ) attached to the bearing block 1. On the retaining plate 3, two rollers 2 are spaced from each other. The rollers 2 are arranged so that they are along a contact line B (see Fig. 3 ) on its circumference. So they support each other and roll off each other. With locking pins 21 they are secured against falling out. Since the locking pins 21 do not have to absorb any bearing forces, they are weakly dimensioned and in and of themselves do not require any extra support for the rollers 2 on the locking pins 21. It is even possible to carry out a design without drilling through the rollers 2. The geometric arrangement and design of the jaws can prevent falling out of the rollers 2. The safety function in permitting rotational movement of the rollers 2 is also ensured if the roller inner diameter is much larger than the diameter of the locking pins 21 and thus much play is present, suitable surfaces on the locking pin 21 and on the through holes of the rollers 2. It can, for example, steel rollers are used with locking pins 21 made of bronze, which guarantees a permanent self-lubrication here. Finally, a dirt wiper 6 is also attached to the retaining plate 3, specifically in a region facing the retaining pin 61 in use of the pressing tool.

The rollers 2 are based on the one hand, as described, against each other and on the other hand against suitable sliding bearing surfaces 11, 12 on the bearing block 1. The main load of the rollers 2 when pressing the pressing tool is on the one hand by the separation of the Abrollflanken 63 of the jaws 62 generated. The direction of this load takes place via the roller surface in a straight line through the centers of the rollers 2 to the respective other role. The rollers 2 are therefore based on each other. This means that this load must be absorbed and transmitted by any storage and thus not by the securing pins 21 and the holding plates 3.

A second type of loading of the rollers 2 is effected by the relative movement of the piston rod 52 and thus of the bearing block 1. This load is always perpendicular to the bearing block 1, ie in the axial direction R. For this purpose, the bearing block 1 with the sliding bearing surfaces 11, 12 is provided. The sliding bearing surfaces 11, 12 are formed in the bearing block 1. For more information on the geometric design of the sliding bearing surfaces, see also Fig. 5 , In this case, the lowest point of the indentation between the periphery, so the outer edge of the bearing block 1 and its center. The said forces are thus transmitted in principle perpendicular to the sliding bearing surfaces 11, 12. In order to Now, the sliding friction of the surfaces of the rollers 2 on the slide bearing surfaces 11, 12 is not too large and inhibits the operation of the pressing tool, the type of surfaces of the rollers 2 and 12 of the sliding bearing surfaces 11, matched. They can be hardened, sintered or coated. For example, a carbonitriding, a Teflon coating of the sliding bearing surfaces or the like is suitable. The choice of a ceramic material for the bearing block 1 and steel rollers 2 with hardened surfaces is suitable. Also conceivable is the choice of other, special material pairings. For example, a pair of chrome steel rollers with a nylon 6 bearing block can provide a suitable result. In this case, one additionally obtains a shock absorption without impairing the pressing force. In addition, depending on a lubricating groove 13 each slide bearing surface 11, 12 are provided, which can serve both for the supply of some lubricant, as well as for the removal of any abrasion.

Overall, this construction thus has considerable advantages in terms of the absorption of the forces occurring. To accommodate the largest forces, the rollers 2 are mutually supported. Its axis of rotation is not loaded and can be limited to a safeguard against falling out of the rollers 2.

In the area between the contact surfaces of the rollers 2 with the sliding bearing surfaces 11,12 and the contact line B of the two rollers 2 is a dirt collecting space 71 (see Fig. 3 ), which has lateral dirt removal spaces 72 at least in a region near the contact surfaces 11, 12. The dirt collecting space 71 is approximately triangular, while the Schmutzabführräume 72 itself extend laterally thereof, are relatively flat and are in communication with the dirt collecting space 71. Both the dirt collecting chamber 71 as well as the Schmutzabführräume 72 serve to accommodate accumulation of contamination in such a way that no jamming occurs even after prolonged operation of the pressing tool.

The Fig. 5 finally shows the new roller holder unit with the bearing block 1 in an exploded view. In the present exemplary embodiment, it is particularly clear that the slide bearing surfaces 11, 12 each have planar surface portions 11a, 12a and raised surface portions 11b, 12b. The planar surface portions 11a, 12a are at right angles to the axial direction R. The raised surface portions 11b, 12b may be flat or curved and in the present case adjoin a mounting surface 7, also at right angles to the axial direction R, to which the retaining plate 3 can be screwed. The mounting surface 7 thus approximately forms the base side of the substantially triangular dirt collecting space 71 between the rollers 2. In the limiting case, the dirt collecting space 71 can be chosen so large that the sliding bearing surfaces 11 and 12 (together with the mounting surface 7) form a single flat surface.

There are also other possible embodiments of the sliding bearing surfaces 11 and 12 and the Schmutzaufangraumes 71 possible. Thus, the sliding bearing surfaces 11,12, for example, have a radius of curvature which is greater than the radius of curvature of the roller 2 and it can be provided a lateral attachment of the retaining plate 3.

The bearing block 1 and the sliding bearing surfaces 11, 12 may be made of the same material in one piece, or it may be provided with a different two-part construction with different materials. Since in the exemplary embodiment the retaining plate 3 is bolted with bolts in the axial direction R with the bearing block 1, thus can be dispensed with a separate attachment of the sliding bearing surfaces even in two-piece design.

List of reference numbers

1

bearing block

2

roll

3

Halteblech

4

Holding plate fixation

5

Piston-cylinder unit

6

wipers

7

mounting surface

11

friction bearing surface

11a

Flat surface part

11b

Sublime surface part

12

friction bearing surface

12a

Flat surface part

12b

Sublime surface part

13

lubrication

21

safety pin

50

Seal retainer ring

51

cylinder head

52

piston rod

53

Spring thrust washer

54

Pressure washer fitting

55

Forked recording

57

compression spring

58

dowel pin

59

scraper

60

locking pliers

61

retaining bolt

62

jaws

63

Abrollflanken

70

drive unit

71

Dirt collecting space

72

Schmutzabführraum

R

axial direction

B

contact line

Claims (7)

Roll-holding unit with rollers (2,2 ') for an electrically, electro-hydraulically or pneumatically operated pressing tool with a piston-cylinder unit (5), wherein the clamping jaws (62) are connected by means of a retaining bolt with a fork-shaped receptacle (55), wherein the rollers (2) Roll on the jaws (62) of a pair of pliers (60) while moving the gripping pliers (60) through the piston-cylinder unit (50), the pressing being accomplished by pushing apart the jaws (62) at the back by movement the rollers (2) in an axial direction R, and wherein the roller holder unit comprises a bearing block (1) and at least one lateral retaining plate (3) arranged thereon, in which two rollers (2) are freely rotatably held by locking pins (21) in a manner in that the rollers (2) contact one another at their outer circumference in the area between the locking pins (21) along a contact line (B), and wherein the bearing block (1) is in contact with each roller Le (2) is provided with a sliding bearing surface (11,12), characterized in that in the area between contact surfaces of the rollers (2) with the sliding bearing surfaces (11,12) and the contact line (B) of the two rollers (2) a dirt collecting space (71) is present. Roller holder unit according to claim 1, characterized in that the dirt collecting space 71 in a Region near the contact surfaces has lateral Schmutzabführräume (72). Roller holder unit according to claim 1, characterized in that the dirt collecting space (71) is so large that the sliding bearing surfaces (11,12) form a continuous flat surface. Roll holder unit according to claim 1 or 2, characterized in that the sliding bearing surfaces (11,12) of the bearing block (1) each have a right angle to the direction R lying flat surface part (11a, 12a) and a raised planar or curved surface part (11b, 12b) , Roller holder unit according to claim 1 or 2, characterized in that the sliding bearing surfaces (11,12) of the bearing block (1) have a radius of curvature which is greater than the radius of curvature of the roller (2). Roller holder unit according to one of claims 1 to 5, characterized in that the holding plate (3) is bolted with bolts in the axial direction R with the bearing block 1. Roller holder unit according to one of claims 1 to 6, characterized in that the holding plate (3) has a dirt wiper , which is mounted on the bearing block (1) remote from the side of the rollers (2) on the holding plate (3).

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