DE3113482A1 - "POWER SCREWDRIVER" - Google Patents

Abstract

1. Power-driven screw-driving tool comprising 1.1 a wrench head casing (10, 40) including a ring (11) to receive a button die, 1.2 a support element (27) mounted movably at the wrench head casing (10, 40) capable to be applied to a fixed support and 1.3 a piston-cylinder-unit (28, 29) acting between the wrench head casing (10, 40) and the support element (27) and moving the wrench head casing relative to the support element, characterized in that 1.4 the wrench head casing (10, 40) contains a guideway (22) for the support element (27), 1.5 the support element (27) is displaceable in the guideway (22) and 1.6 the support element (27) freely projects from the one end of the guideway (22).

Description

VONKREISLER "SCHONWALD" eVSHOLD FUES FROM KREISLER KELLER SELTING WERNER

Applicant PATENTANWÄLTE

Paul-Heinz Wagner Dr, lng. by Kreisler11973

Dr.-Ing. K. Schönwald, Cologne

House No. 70 Dr.-Ing. K. W. Eishold, Bad Soden

Dr.J.F. Fues, Cologne

Much-Birrenbachshöhe DipL-Chem. Alek von Kreisler, Cologne

DipL-Chem. Carola Keller, Cologne Dipl.-Ing. G. Selting, Cologne Dr. H.-K. Werner, Cologne

DEICHMANNHAUS AT THE MAIN RAILWAY STATION

D-5000 COLOGNE 1

April 2, 1981 Sg-f ζ

"Power wrench"

The invention relates to a power wrench consisting of

1.1 a key head housing with a ring for Picking up a key nut,

1.2 a movably attached to the key housing Support element for attachment to a fixed support and

1.3 one acting between the key head housing and the support element, the key head housing relative to the supporting element moving piston-cylinder unit.

According to a state-of-the-art, not previously published Proposal (patent application P 30 08 332.0-15) is the pressure medium cylinder inside the Key head housing. The one in the pressure cylinder

Telephone: (0221) 131041 · Telex: 8882307 dopa d ■ Telegram: Dompotent Cologne

Π 13482

The linearly movable piston is attached to a support element via a piston rod articulated at both ends supported, which is mounted coaxially to the ring axis on the key head. When using the power screwdriver the support element is placed against a stationary abutment and the piston in the pressure medium cylinder extended. The key head housing is relative to the stationary supported support element pivoted around the ring axis. During this pivoting movement, a key nut stored in the interior of the ring is released taken by a ratchet so that a screw head inserted into the wrench socket is turned. At the Return stroke of the piston turns the key head housing into Swiveled in the opposite direction, whereby the key nut is not carried along by the ratchet.

Although the power wrench described compared to conventional power wrenches already in its dimensions and in Weight is significantly reduced, is due to the approximately tangential to the ring protruding from the key head housing Support element takes up additional space and also the weight of the entire power screwdriver co-determined to a not inconsiderable extent by the support element mounted on the key head.

The invention is based on the object of creating a power wrench of the type mentioned at the beginning which a storage of the support element on the key head housing is not required and with a relative lightweight and small-volume support element gets by.

To solve this problem is provided according to the invention / that

1.4 the key head housing a guideway for the Having support element,

1.5 the support element is displaceable in the guide track, and

1.6 the support element protrudes freely from one end of the guideway.

As a result, there is no need for the support element to be pivoted on the key head housing. Of special The advantage is the space and weight saving of the entire power screwdriver, which is achieved by the invention.

If the guide track for the support element is straight, it should run so that the piston-cylinder unit approximately in the middle stroke position at right angles to the line that passes through the center of the ring and through the piston of the piston-cylinder unit.

In the case of hydraulic power wrenches, the Desire to determine the screw torque with which the wrench head acts on the screw head based on the pressure, with which the inside of the pressure medium-operated cylinder is acted upon. This pressure can be very easily be measured. When an approximately linear relationship between the pressure and the screw torque can

Screw torque can be determined in this way. If the support element on which the piston rod engages, is mounted on the key head housing and protrudes approximately tangentially from this, the stationary Abutment against which the support element is placed, often at different distances from the axis of the Have key head housing. But now there is a given one Pressure in the cylinder the torque acting on the screw head depends on the distance, which the stationary abutment has from the axis of the key head housing, or from the length of the moment arm, with which the abutment makes the support. A similar dependence on the length of the support moment arm results when the torque is determined by strain measurements on the wrench head housing.

In order to enable a relatively precise determination of the torque by means of pressure measurement or strain measurements, according to an advantageous development of the invention provided that

2.1 the guideway in a circular arc around the axis

of the ring runs.

The support element consists of a curved segment that extends from the piston-cylinder unit to the key head housing can be extended and that moves on a circular arc path around the ring axis. Due to the circular arc shape of the support element, the moment arm does not change during the screwing process, because the position of the support element does not change.

Rather, the key head housing is rotated relative to the stationary, fixedly supported support element the ring axis pivoted back and forth. This means that during a piston stroke the dependency the screw torque remains largely linear from the pressure in the cylinder. So it is possible to use the screwing device switch off when a certain pressure is reached in the pressure line leading to the cylinder. It is ensured that

then the torque corresponding to this pressure is reached. This linear pressure dependence is with the known power screwdrivers are generally not available because there is the angle at which the piston-cylinder unit attacks on the key head housing, changed greatly during a stroke.

In an advantageous development of the invention it is provided that

3.1 the cylinder of the piston-cylinder unit from a cylindrical, rectilinear cavity

consists in the interior of the support element and

3.2 the piston is articulated to one end of a rod, the other end of which is articulated supported on the key head housing

is.

This converts the linear movement of the piston in the cylinder into a circular arc-shaped movement of the support part, wherein the support part forms the cylinder at the same time. Alternatively, the support part can also be designed as a piston be while the cylinder is mounted on the key head housing and freely on the respective Adjusts positions of the piston or support part. In

in each case is thereby / that either the cylinder or the piston is made in one piece with the support element or is even formed inside the support element, which The design and weight of the power screwdriver are reduced.

A variant of the power screwdriver according to the invention is characterized in that

4. 1 the ring in a pivot bearing of the key head housing is stored and

4 .2 between the key head housing and the ring Ring only in one direction of rotation of the key

head housing driving ratchet is effective.

Such ratchets belong - also in connection with power screwdrivers - the state of the art.

The power wrench according to the invention does not necessarily have to be be equipped with a ratchet, but it can also be designed so that after each stroke movement of the Piston-cylinder unit a manual implementation is made. To this end, according to a second variant of the invention provided that

5.1 the key head housing from the ring and a rigidly connectable to the ring, the guide track having approach and

5. 2 the approach on a rail of the ring that runs coaxially to the ring axis slidable and lockable in different positions.

Such a power wrench without a ratchet is still lighter and more space-saving than a device with a quick design.

When using it, however, after each piston stroke the manual conversion of the ring must be compared to the Key head housing and after at least every second piston stroke the manual repositioning of the entire device to be accepted compared to the element to be rotated.

In the following, two exemplary embodiments of the invention are explained in more detail with reference to the drawings.

Show it:

Figure 1 is a longitudinal section through a power wrench with ratchet,

FIG. 2 shows a cross section along the line II-II of FIG Figure 1,

FIG. 3 shows a partial longitudinal section through a power wrench without a ratchet and

FIG. 4 shows a cross section along the line IV-IV in FIG.

In the embodiment of Figures 1 and 2, the power wrench has a wrench head housing 10, in which a ring 11 is rotatably mounted. The ring 11 is provided with an internal toothing 12 into which an axially provided with a corresponding external toothing The key nut can be inserted so that the key nut is connected to the ring 11 in a rotationally fixed manner. The ring 11 is in the key head housing 10, from which he after both Sides protrudes slightly, anchored with a snap ring 13 (Figure 2) so that it cannot be lost, but is free is rotatably supported by the key head housing 10. At the peripheral wall of the ring 11 is toothed 14, which cooperates with a ratchet 15. The ratchet consists of a toothed segment 16, which is in a cavity 17 of the key head housing 10 is housed and engages with its toothing in the external toothing 14 of the ring 11. The toothed segment 16 has on his The rear side has a dome-shaped recess along an inclined shoulder, into which a ball 18 is inserted. the Ball also protrudes into a dome-shaped recess the end face of a pressure piece 19 into it. The rear end of the pressure piece 19 is connected to another Ball 20 is supported on a wall of the key head housing 10. It runs through a bore 21 through which is directed so that the extension of its axis is almost tangential to the ring 11. Since the diameter of the Bore 21 is so large that the pressure piece 19 pendulum

can execute movements in the bore 21, the toothed segment 16 can be disengaged from the external toothing 14 loosen. However, if the key head housing 10 is pivoted clockwise about the axis of the ring 11, then the pressure piece 19 acts with the joints formed by the balls 18 and 20 as a toggle mechanism, through which the toothed segment 16 in the Toothing 14 is pressed into it. In this way occurs only when the key head housing 10 is rotated in Clockwise the ring 11 is taken along by the ratchet 15.

The key head housing 10 also has a circular segment-shaped guide track 22 which is curved around the axis of the ring 11. This guide track 22 consists of a cavity, the outer peripheral wall 23 and inner peripheral wall 24 of which extend in the shape of a circular arc, while the side walls 25, 26 are flat. As FIG. 2 shows, the guide track 22 has a rectangular or square cross section. In the circular arc-shaped guideway 22 is the support member 27 according to Figure 1 is also curved in a circular arc shape and has an ⁿ of the guideway 22 adapted cross-section. The support element 27 is displaceable along the circumferentially completely closed guide track 22 so that its outer end 27 ′ can be moved out of the guide track 22 and thus out of the key head housing 10. The outer end 27 'of the support element 27 is against a fixed support, for example against a wall or an adjacent screw head.

sets in order to dissipate the reaction force that arises when screwing.

Inside the support element 27 is the cylinder space 28, incfem the piston 29 linearly displaceable is. The center of the longitudinal axis of the cylinder space 28 is approximately perpendicular to a radius of the ring 11, so that a favorable external use of the pressure force acting between the piston 29 and the support element 27 to form a torque for the key head housing 10 is achieved will.

The piston 29 has a tubular shape at its rear end Approach 3 0, which passes through the end wall 31 of the cylinder space 28 in a sealing manner. The tubular approach 3 0 has a smaller diameter than the front piston surface 32, so that the cylinder chamber 28 through the Piston 29 is divided into two parts. Each of these parts is via a hydraulic line with a (not shown) hydraulic switching valve connected. The hydraulic lines lead through the support element 27. In Figure 2 is a hydraulic line 33 is visible.

A piston rod 34 runs through the tubular extension 30 at a radial distance, one end of which is connected to the piston 29 via a ball joint 35, while the other end is connected to the key head housing via a joint 36 10 is supported

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Piston 29 within the cylinder space 28, the piston rod 34 runs approximately coaxially to the axis of the Cylinder space 28.

By alternating that part of the cylinder space 28 that lies in front of the piston 29 / and that part / that is behind the piston 29, are acted upon with pressure medium, when the support element 28 is fixed, the Key head housing 10 around the axis of the ring 11 pivoted. When the end 28 of the support element 27 against If a stationary abutment is set, a screw head coupled non-rotatably to the ring 11 can be replaced by alternating Moving the wrench head housing 10 back and forth can be tightened, the entrainment of the screw head by the Ratchet 15 takes place only when the piston 29 is extended (to the right according to FIG. 1), while during the return stroke of the piston 29 (from right to left according to FIG. 1) the ratchet 15 is empty on the external toothing of the ring 11 slides.

Instead of the described guide track 22, which has a hollow profile that is closed on all sides, it is also possible an open or partially closed guideway can be used. It is only important that an exact guidance of the Support element 28 takes place along an arcuate guide path, the center of which is at least approximately lies on the axis of the ring 11.

In the embodiment according to FIGS. 3 and 4, there is one from the extension 43 and exchangeable ring inserts 41 existing housing 4 0 is provided. The ring insert 41 is rigid overall and has a star-shaped shape Inner contour 42, which forms the key nut. The inner contour 42 is designed in a known manner so that that a hexagonal screw head, which goes into the wrench socket, returns after a turn of 30 fits in the key nut. The device can therefore at the earliest after a rotation angle of 30 ° in its entirety. be implemented on the screw head. To change the torque during the rotary movement as much as possible The angle of rotation resulting from the stroke of the piston-cylinder unit must be kept small. To anyway To achieve the pitch angle of the ring insert 41 or a multiple thereof, the ring insert 41 is detachable and pivotally connected to the extension 43. For this purpose, the ring insert 41 has a circular arc shape on part of its circumference Guide rail 44 which, as FIG. 4 shows, is T-shaped in cross section. The T-shaped guide rail 44 is pushed into a T-shaped groove 45 of the projection 43. Thus, the approach 4 3 on the Guide rail 44 can be pivoted around the axis of the ring insert 41. The coupling of the approach 43 with the The ring insert 41 is made by bolts 46 which pass through bores 47, 48 of the guide rail 44 or of the attachment 43 go through. The bores 47 and 48 of the parts 41 and 43 are aligned in certain positions of these parts, so that a bolt 46 can be inserted through it.

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In the case of the inner contour 42 of the key socket shown in FIG. 3, at least every 15 Degrees of angle of the displacement of the projection 4 3 relative to the ring one consisting of the bores 47 and 48 Pair of holes are formed through which a bolt 46 can be inserted.

In this way, despite the smaller angle of rotation per stroke predetermined by the piston-cylinder unit the required angle of rotation of at least 30 to move the device! can be achieved.

In order to avoid frequent repositioning of the shoulder 43 on the ring insert 41, at the outer end 27 ' of the support element 27 an adjustable extension can be attached, for example from a strong screw. After the support element 27 has been moved out, the support element can be wholly or partially be withdrawn again. Thereafter, the adjustable extension is attached to the end 27 of the support element 27 attached and the support element extended again.

Instead of an adjustable extension, an interchangeable adapter can be temporarily attached to the End 27 'of the support element 27 are attached. This results in a saving in stroke with simple means .

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Claims (5)

-JLA- claims.) Power screwdriver, consisting of 1.1 a key head housing with a ring to hold a key nut, 1.2 a movable on the key head housing attached support element for attachment to a solid_ support and 1.3 one acting between the key head housing and the support element, the key head housing relative to the piston-cylinder unit moving relative to the support element, characterized in that 1.4 the key head housing (10, 40) has a guide track (22) for the support element (27), 1.5 the support element (27) is displaceable in the guide track (22), and 1.6 the support element (27) protrudes freely from one end of the guide track (22). 2. Power wrench according to claim 1, characterized in that that 2.1 the guide track (22) runs in the shape of a circular arc around the axis of the ring (12). 3. Power wrench according to claim 1 or 2, characterized marked that 3.1 the cylinder (28) of the piston-cylinder unit (28,29) from a cylindrical cavity consists in the interior of the support element (27), and 3.2 the piston (29) is articulated to one end of a piston rod (34), the other end of which Articulated end on the key head housing (10) is supported. 4. Power wrench according to one of claims 1 to 3, characterized in that 4.1 the ring (12) in a pivot bearing of the 'key head housing (10) is stored, and 4.2 between key head housing 10 and ring 11, one the ring only in one direction of rotation the key head housing (10) driving ratchet (15) is effective. 5. Power wrench according to one of claims 1 to 3 ,. characterized in that - IL - -3 - 5.1 the key head housing (40) the ring (41) and one which can be rigidly connected to the ring and has the guide track (22) Approach (43) exists, and 5.2 the extension (43) on a rail (44) of the ring running coaxially to the ring axis (41) is slidable and lockable in various positions.