EP1920888B1 - Torque impulse tool and front plate therefor - Google Patents

Abstract

The pulse tool (1)has a drive unit (2) and a pulse unit (3) having a rotor (4) with at least two blades (5, 6) inside a hydraulic cylinder (9), and a front plate (10) through which a drive spindle (11) passes. The front plate has at least one bypass aperture connecting high and low pressure chambers separated by the blades.

Description

The invention relates to a pulse tool, in particular impulse wrench, with a drive unit and a pulse unit driven by this pulse unit having at least one rotor with at least two fins, a hydraulic cylinder surrounded this and a drive spindle projecting from the hydraulic cylinder on one side by a front plate. The front plate is disposed between the rotor and a front cover of the pulse unit formed with a hydraulic fluid filling means.

Such a pulse tool is from practice, for example from the DE 20 210 453 U is known and used, for example, to perform by means of the drive spindle and a corresponding tool on the drive spindle a screw. The speed of such a screw essentially determines the economy of the pulse tool. The faster the screw connection, the higher the efficiency. This is hard. Screw connections with a small tightening angle usually unproblematic. However, if the screw connection is softer, the pulse tool may take a few seconds to produce the screw connection in the desired manner. Such a long period of time is usually unacceptable. In order to ensure economic screwing in any case, pulse frequencies between 20 Hz and 30 Hz are preferred.

In a production of corresponding pulse tools has been found that the pulse frequency vary within certain limits and in comparison to the above-mentioned pulse frequencies quite a few Hz may be too large or too small.

US 5,611,404 shows a pulse tool with a drive unit and a pulse unit. A pressure plate is disposed between fins and an end cover. The pressure plate has a primary passage and a secondary passage. The primary passage serves to compensate for an expansion of the fluid due to an increase in temperature due to the actuation of the pulse tool. The secondary passage connects the primary passage to a slot. The secondary passage is intended to relieve pressure spikes during reverse actuation of the pulse tool, the slot forming an area with lower pressure. Furthermore, the secondary passage is used to assist in the escape of air during filling of the tool with fluid.

DE 2 02 10 453 US discloses a pulse unit for a screwdriver having a rotor and a number of blades. These are adjustable in radial Richter and stored in guide grooves of the rotor. Chambers formed between the rotor and the rotor cylinder are separated by the lamellae. A bypass connects two chambers with each other and the bypass is associated with an adjustable locking device.

Object of the present invention is to compensate for corresponding deviations in the desired pulse frequencies in a simple manner and in particular already during assembly of the pulse tool.

The object is solved by the features of patent claim 1.

According to the invention for this purpose, the front plate of the pulse tool through the slats on separate high-pressure and low-pressure chambers connecting bypass openings.

By opening or closing at least one bypass opening, the pulse frequency can be increased or decreased accordingly, with hydraulic fluid can flow from the high-pressure to the low-pressure chamber when the bypass opening is open, whereby the pulse frequency is increased. The corresponding increase in the pulse frequency depends in particular on the opening diameter of the corresponding bypass opening, wherein at a larger opening diameter a faster hydraulic fluid exchange between the above chambers and thus a faster driving over the corresponding sealing webs of the hydraulic cylinder can be carried out by the corresponding slats.

Similarly, by closing a bypass opening, the pulse frequency can be lowered.

By only one bypass opening, however, only relatively few variations of the pulse frequency are possible. For example, by opening or closing a bypass opening, the pulse frequency can be increased or decreased by a few Hz. For more variations of the pulse frequency, according to the invention, two or more bypass openings form a bypass opening group. These bypass ports of the bypass port group may then be used by opening one or more bypass ports to a corresponding change in pulse frequency. In this case, a bypass opening group connects according to high-pressure and low-pressure chamber of the pulse unit. That is, all the bypass openings of the bypass opening group can be used for the corresponding hydraulic fluid exchange between the chambers in any combination. If such a bypass opening group, for example, consists of three bypass openings, then it goes without saying that one, two or all three bypass openings can be opened or correspondingly closed by associated closing bodies.

The opening diameters of each bypass opening of each bypass opening group are different. This means that, for example, the bypass opening with the largest opening diameter alone is closed in order to allow a certain pulse frequency increase, while opening the bypass opening with the smallest opening diameter, a lower pulse frequency increase is realized. Again, corresponding combinations of opening or closing of all bypass openings of a bypass opening group are possible.

In principle, there is the possibility that a corresponding bypass opening is formed only after a first test of the pulse tool with respect to the corresponding pulse frequency in the front plate. Depending on the desired change in the pulse frequency, the bypass opening is equipped with a corresponding opening diameter. It is also possible to at least partially close an already existing bypass opening, in order to change the pulse frequency accordingly, or to vary the opening diameter of the bypass opening. For example, the aperture diameter could be increased if a corresponding increase in pulse frequency is desired.

A simple way to close and corresponding opening of each of the bypass openings can be seen in that it is closed by means of a arranged between the front plate and front cover, in particular spherical closing body. Depending on the desired change in the pulse frequency, the corresponding closing body is removed or used to close a bypass opening.

If, for example, four or more lamellae are used for the pulse unit, then two or more high-pressure and low-pressure chambers are also respectively separated by these in pairs. In this context, it may also be advantageous if bypass opening groups are arranged in pairs diametrically opposite each other. An arrangement is made such that in each case a bypass opening group is associated with a high pressure chamber, each high pressure chamber can be assigned its own bypass opening group.

In general, a pulse tool described above is designed not only for one direction of rotation, but for clockwise and counterclockwise rotation. In order to be able to change the pulse frequency correspondingly in both directions of rotation, bypass opening groups for right and left rotation of the drive spindle can be arranged. Arrangement of the bypass opening groups, number of the bypass openings of each bypass opening group, and diameter of each bypass opening may be varied according to the foregoing.

There is the possibility that each high-pressure chamber is associated with a corresponding bypass opening group, and it may also be sufficient if only one or two of the high-pressure chambers zugerordnet a corresponding bypass opening group.

In order to be able to close each of the bypass openings by only one type of closing bodies, it is certainly favorable if the closing body for each bypass openings each have the same diameter. This can be effected in particular in that each bypass opening in the direction of the front cover has a correspondingly formed sealing seat for the closing body, wherein the sealing seat can be formed by a substantially conical widening of the bypass opening. This conical extension can be identical for all bypass openings, so that accordingly closing bodies with the same diameter or the same dimensions can be used.

The pulse tool is filled prior to delivery to the user with hydraulic fluid, the filling usually takes place directly at the pulse unit. For this purpose, a corresponding Hydraulikfluidbefülleinrichtung is used. In order to facilitate a filling of the pulse unit with hydraulic fluid in a simple manner, the hydraulic fluid filling device of the cover has at least one in particular closable filling opening. Through this, the pulse unit is filled with hydraulic fluid under a vacuum and, in particular, care is taken in such a filling that no bubbles remain within the pulse unit.

After filling the pulse unit this can then be arranged in the pulse tool and connected to the corresponding drive unit. Before, the filling opening is correspondingly closed, for example by a screw-in sealing pin or piston and optionally a closing body.

Advantageously, the filling opening can be aligned relative to each bypass opening, so that the corresponding closing body for the bypass openings can be inserted and removed through the filling opening.

With regard to the opening diameters of the corresponding bypass openings of each bypass opening group, it should also be noted that these can change for right or left rotation in the reverse order at the corresponding bypass opening group.

As already described, the pulse frequency can be varied by the bypass openings and the pulse tool can be delivered with a specific basic pulse frequency. However, during the use of the pulse tool, there is the possibility that this pulse fundamental frequency changes, for example, due to leakage of hydraulic fluid, temperature changes of the hydraulic fluid and thus caused pressure changes, etc. In order to allow adjustment of the fundamental frequency with respect to these influences during operation, the pulse unit their end facing the drive spindles having a fluid chamber connected to a compensation chamber. This compensation chamber may be in volume, i. Compensation volume, to compensate for the previous influences are varied. Such a variation can be done for example by an elastic membrane as a boundary of the compensation chamber. The elastic membrane is deflected when the hydraulic fluid occupies a higher volume at higher temperatures, so that the corresponding additional volume is absorbed by the compensation chamber by deflecting the membrane and thereby the basic pulse frequency is maintained unchanged. When the hydraulic fluid cools again, hydraulic fluid from the balance chamber is returned to the pulse unit through the corresponding fluid port.

It is also advantageous in this context if the corresponding compensation chamber can not only be varied in its compensating volume as a function of the pressure, but instead can be varied independently of the pressure. As a result, there is the possibility, for example, of providing a larger compensating volume during a first filling of the pulse unit with hydraulic fluid, which can compensate in particular for corresponding leakages in the further use of the pulse unit in a simple manner.

A simple possibility for such a pressure-independent variable compensation volume can be seen therein when the compensation chamber is bounded by the hydraulic cylinder and in particular by rotation in the longitudinal direction adjustable compensating piston. The balance piston can be rotated by the worker from the outside, so that the corresponding Adjustment of the compensation volume by the operator before, during or even after use of the pulse tool can be done.

In order to fix the corresponding balance piston in a desired rotational position in a simple manner, the balance piston can be fixed in at least one rotational position by means of a fixing device relative to the hydraulic cylinder.

A front plate of the type described above, which can be used with a corresponding pulse tool between pulse unit and front cover, can optionally be used as a retrofit component in already used pulse tools.

In the following the invention with reference to the drawing attached figures will be explained and described in detail.

Fig. 1

eine Seitenansicht eines Impulswerkzeugs mit zumindest Antriebsein- heit und Impulseinheit;

Fig. 2

einen Längsschnitt durch eine Impulseinheit mit Antriebsspindel;

Fig. 3

einen Schnitt entlang der Linie III-III einer entsprechenden Impulsein- heit (aus Fig. 2);

Fig. 4

eine Detaildarstellung eines vorderen Endes der Impulseinheit nach Fig. 2 und

Fig. 5

eine Vorderansicht einer Vorderplatte nach Fig. 4.

Show it:

Fig. 1

a side view of a pulse tool with at least drive unit and pulse unit;

Fig. 2

a longitudinal section through a pulse unit with drive spindle;

Fig. 3

a section along the line III-III a corresponding impulse unit (out Fig. 2 );

Fig. 4

a detail of a front end of the pulse unit after Fig. 2 and

Fig. 5

a front view of a front plate after Fig. 4 ,

Fig. 1 shows a side view of a pulse tool 1 with at least one drive unit 2 and a pulse unit 3. From the pulse unit 3 is a drive spindle 11 before, on a corresponding tool, for example, for a screw connection can be attached, such as a socket or the like.

As a rule, such a pulse tool is equipped with a pneumatic motor as a drive unit and can usually be operated both for tightening as well as for loosening a screw with clockwise and counterclockwise rotation.

In Fig. 2 In particular, the pulse unit 3 is after Fig. 1 shown in a longitudinal section. The pulse unit 3 is arranged in a possibly multi-part housing 35. The pulse unit 3 has a rotor 4 which is drive-connected to the drive unit 2. In the rotor 4 radially adjustable slats 5, 6, 7 and 8 are mounted, see also Fig. 3 , In each case two diametrically opposite slats 5, 6 and 7, 8 are acted upon radially outward by corresponding compression springs 36. The free ends of the slats 5, 6, 7, 8 are in the range of sealing webs 37, see also Fig. 3 , on an inner contour of a hydraulic cylinder 9, separating high and low pressure chambers 14, 15 from each other. Rotor, vanes, seal lands, and hydraulic rams cooperate in a conventional manner to produce pulse bursts at a particular pulse frequency. In general, a pulse frequency is 20 to 30 Hz, as at such a pulse frequency economic screwing is guaranteed.

The pulse unit 3 has at its in Fig. 2 left end on a front plate 10 and a front cover 12. The front plate 10 is disposed between substantially rotor 4 and fins 5, 6, 7, 8 and the front cover 12. In the front cover 12, a Hydraulikfluidbefülleinrichtung 13 is arranged. This comprises at least one filling opening 24, which can be closed by a closing ball and a screw-in sealing pin or piston 38 and 39 after filling the pulse unit 3 with hydraulic fluid.

By the front cover 12, the pulse unit is sealed on the side of the drive spindle 11, so that hydraulic fluid via sealing gaps between the front plate 10, front cover 12 and rotor 4 or lamellae 5, 6, 7, 8 between the high pressure and low pressure chamber is interchangeable.

The drive spindle 11 passes through both the front plate 10 and the front cover 12 and is for the arrangement of a corresponding tool from the pulse tool 1 before.

At its end facing the drive spindle 11 end 25, the pulse unit 3 has a fluid opening 27 in the hydraulic cylinder. Through these are the chambers 14, 15, see also Fig. 3 , in the interior of the pulse unit 3 with a compensation chamber 26 with a corresponding compensation volume 28 in connection. This compensation chamber 26 is delimited by the hydraulic cylinder 9 and a compensating piston 29 which can be adjusted in the longitudinal direction 30 by turning.

In the in Fig. 2 illustrated position, the balance piston 29 is rotated as far as possible in the direction of hydraulic cylinder 9, so that the corresponding compensation chamber 26 substantially only by the in Fig. 2 illustrated cylindrical chamber is formed.

The balance piston 29 can be relative to the hydraulic cylinder 9 in Fig. 2 Adjust to the right, whereby the compensation chamber 26 receives a larger compensation volume 28. Certain rotational positions of the balance piston 29 can be fixed by a pin as a fixing device 31, wherein, for example, four, six or more rotational positions in a revolution of the balance piston 29 are fixed accordingly.

In Fig. 3 is a section taken along the line III-III Fig. 2 shown. In particular, the arrangement of the high-pressure chambers 14 and low-pressure chambers 15 between two slats 5, 6, 7 and 8 can be seen here. These are mounted radially adjustable in the rotor 4 to the outside and pressurized spring. In the position shown Fig. 3 are two high-pressure chambers 14 and two low-pressure chambers 15 each diametrically opposite one another, wherein the corresponding blades 5, 6, 7, 8 are just in sealing contact with corresponding sealing ridges 37. The direction of rotation after Fig. 3 is denoted by the reference numeral 34, in this context, a clockwise rotation of the rotor or according to the drive spindle 11, see also Fig. 2 , he follows.

In Fig. 4 is a detailed representation of the pulse unit 3 in particular for front plate 10 and front cover 12 is shown. Visible are in the front plate bypass openings 16 and closing body 19 in the form of closing balls that close these bypass openings. The closing balls 19 are held between the front plate 10 and the front cover 12. The bypass openings are in communication with the corresponding chambers in the interior of the pulse unit 3. Each bypass opening 16, 17, 18, see also Fig. 5 , Towards the front cover 12 has a receiving seat 33 for the arrangement of the corresponding closing ball 19. The receiving seats 33 have the same cross-section for all bypass openings, so that each of the bypass openings 16, 17, 18 can be closed by a closing ball 19 with the same diameter. Each receiving seat 33 has, as a cross-section, substantially a conical part extending from a corresponding opening diameter 23 of the bypass openings and an adjoining substantially cylindrical part. With the conical part, the closing ball 19 is in sealing contact.

The opening diameters 23 of the various bypass openings 16, 17, 18 are different, see in particular Fig. 5 ,

The corresponding bypass openings 16, 17, 18, are after Fig. 5 to bypass opening groups 20, 32, 22 and 32 are summarized. The bypass opening groups 20 and 21 are with the corresponding high-pressure chambers 14 after Fig. 3 in conjunction, wherein an analogous connection through the bypass opening groups 22 and 32 with high-pressure chambers in a reverse run, ie, counterclockwise Fig. 3 he follows.

According to the embodiment Fig. 5 Each bypass opening group has three bypass openings 16, 17, 18. The arrangement of the bypass openings 16, 17, 18 takes place for the bypass opening groups 20 and 21 in the same and for the bypass opening groups 22 and 32 in the reverse direction. The various bypass openings 16, 17, 18 have decreasing opening diameters 23 in this order. That is, the two bypass opening 16 has the largest and the bypass opening 18 to the smallest opening diameter.

The bypass opening groups 20, 21 and 22, 32 are arranged diametrically opposite one another and assigned to the respective high-pressure chambers. By closing balls 19 unlocked bypass openings 16, 17, 18 penetrates hydraulic fluid into the low-pressure chambers and flows primarily through center 40 of the front plate to the left side accordingly Fig. 4 from the direction of the high-pressure chambers, allowing a hydraulic fluid exchange in this way takes place between the chambers and thus a faster driving over the sealing webs of the hydraulic cylinder is connected by the fins and thus a pulse frequency increase. Depending on the open bypass opening, a larger or smaller hydraulic fluid exchange takes place. For the illustrated three bypass openings 16, 17, 18 of each bypass opening group 20 with correspondingly different opening diameters arise in this way 2 ³ setting options of Hydraulikfluidaustauschches due to appropriately opened bypass openings. As a result, a pulse frequency for setting a corresponding basic pulse frequency eight times by certain amounts can be varied. The corresponding basic pulse frequency is set before delivery of the pulse tool, in particular in the range of 20 Hz to 30 Hz. The corresponding opening diameters of the bypass openings 16, 17, 18 may be in the range of a few tenths of a millimeter. It is also possible to arrange fewer or more bypass openings for each bypass opening group, thereby resulting in correspondingly fewer or more adjustment possibilities for the basic pulse frequency. In general, when using the pulse unit in the clockwise and counterclockwise rotation, a symmetrical assignment of the bypass openings with or without closing body makes sense-this results in both directions of rotation, the same pulse frequency in an analogous arrangement of the closing body. However, it is equally possible to provide different arrangements of bypass openings and / or bypass opening groups for clockwise and counterclockwise rotation in order, for example, to design one impact direction more strongly than the other with other frequency capabilities.

Closing the bypass opening groups 20, 21 in clockwise direction 34 after Fig. 3 , ie when assigning the bypass opening groups 22, 32 to the high-pressure chambers, is not required due to the pressure neutrality between the front and back of the front panel 10. It should again be noted that only those bypass openings are effective, with the Low pressure chamber or low pressure side are in communication. The low pressure chamber changes when the direction of rotation changes. Pressure is primarily in both directions of rotation via the center 40 on the left side of the front panel 10, see for example Fig. 4 , Bypass openings on the pressure side or in association with the pressure chamber 14 with or without closing body are pressure-neutral and therefore ineffective.

The arrangement of the closing body 19 in the corresponding receiving seats 33 takes place through the filling opening 24, wherein the front cover 12 according to the assignment of the filling opening 24 to each of the bypass openings 16, 17, 18 is rotatable.

A corresponding front plate 10 can also be retrofitted for impulse tools already in use as a rule, see in particular Fig. 2 and 4 , wherein only an exchange of a corresponding previously used front plate with the front plate must be made according to the invention.

Claims (14)

1. Pulse tool (1), in particular a pulse wrench, comprising a drive unit (2) and a pulse unit (3) driven thereby, which pulse unit comprises at least one rotor (4) with at least two vanes (5, 6, 7, 8), a hydraulic cylinder (9) surrounding them and a drive spindle (11) which protrudes at one end from the hydraulic cylinder through a front plate (10), the front plate (10) being arranged between the rotor (4) and a front cover (12) formed with a hydraulic fluid filling device (13), characterised in that the front plate (10) comprises bypass openings (16, 17, 18) connecting high-pressure and low-pressure chambers (14, 15) separated by the vanes (5, 6, 7, 8), two or more bypass openings (16, 17, 18) forming a bypass opening group (20, 21, 22, 32) and the opening diameters (23) of each bypass opening (16, 17, 18) of each bypass opening group (20, 21, 22, 32) being different.
2. Pulse tool according to claim 1, characterised in that the bypass opening (16, 17, 18) can be closed and/or varied in its opening diameter (23).
3. Pulse tool according to either claim 1 or claim 2, characterised in that the bypass opening (16, 17, 18) can be closed by means of an, in particular spherical, closing body (19) arranged between the front plate (10) and the front cover (12).
4. Pulse tool according to any one of the preceding claims, characterised in that bypass opening groups (20, 21, 22, 32) are arranged in pairs in the front plate (10) diametrically opposite one another.
5. Pulse tool according to any one of the preceding claims, characterised in that bypass opening groups (20, 21, 22, 32) are arranged for clockwise and anticlockwise rotation of the drive spindle (11).
6. Pulse tool according to any one of the preceding claims, characterised in that a bypass opening group (20, 21, 22, 32) is assigned to each high-pressure chamber (14).
7. Pulse tool according to any one of the preceding claims, characterised in that the closing bodies (19) for each bypass opening have the same diameter.
8. Pulse tool according to any one of the preceding claims, characterised in that the hydraulic fluid filling device (13) comprises at least one, in particular closable, filling opening (24) in the front cover (12).
9. Pulse tool according to claim 8, characterised in that the filling opening (24) can be orientated relative to each bypass opening (16, 17, 18).
10. Pulse tool according to any one of the preceding claims, characterised in that the opening diameters (23) in the bypass opening groups (20, 21, 22, 32) change in the reverse order for clockwise or anticlockwise rotation.
11. Pulse tool according to any one of the preceding claims, characterised in that the pulse unit (3) comprises at its end (25) opposite the drive spindle (11) a fluid opening (27) connected to a compensation chamber (26).
12. Pulse tool according to claim 11, characterised in that the compensation chamber (26) has a compensating volume (28) that can be varied independently of pressure.
13. Pulse tool according to any one of the preceding claims, characterised in that the compensation chamber (26) is defined by the hydraulic cylinder (9) and a compensating piston (29) which in particular is adjustable by rotation in the longitudinal direction (30).
14. Pulse tool according to any one of the preceding claims, characterised in that the compensating piston (29) can be fixed in at least one rotary position relative to the hydraulic cylinder (9) by means of a fixing device (31).

Images