GB2253803A

GB2253803A - Motor-driven open-ended spanner

Info

Publication number: GB2253803A
Application number: GB9205494A
Authority: GB
Inventors: Wolfgang Specht
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1991-03-16
Filing date: 1992-03-13
Publication date: 1992-09-23
Anticipated expiration: 2012-03-13
Also published as: SE9200777L; DE9103252U1; GB9205494D0; GB2253803B; SE9200777D0

Abstract

A motor-driven open-ended spanner 1 has an open spanner wheel 5 which has a friction surface or toothing receiving rotational drive, characterised in that the spanner wheel is driven from at least two points 9, 10, in particular via two friction or gear wheels 11, 12, the distance A between which is greater than the width W of the jaw opening 7. The width W of the jaw opening 7 corresponds approximately to the width across the flats of the spanner wheel 5. <IMAGE>

Description

Motor-driven open-ended spanner Prior art The invention starts from an open-ended spanner according to the preamble of Claim 1. Known open-ended spanners of this type have open spanner wheels which are set in rotation by means of a plunger or a ratchet. In the process, rotation is effected either only in one direction or can be changed only after a latch is changed over. To change the direction of rotation, therefore, either the spanner has to be swung through 1800 or a latch has to be changed over. Both prolong the cycle time in automatic production processes.

Advantages of the invention Against this background, the open-ended spanner according to the invention, having the characterising features of Claim 1, has the advantage that it permits instantaneous reversal of the direction of rotation at a jaw opening enlarged compared with the prior art. This facilitates screwing at double-threaded bolts with both a right-hand and a left-hand thread, such as, for example, track rods of motor vehicles. Furthermore, the reversal of the direction of rotation is of quite general advantage when removing the spanner. Even before the actual screwing operation, it is advantageous to rotate the spanner in the opposite direction in order to find the thread.

Advantageous further developments and improvements of the open-ended spanner specified in Claim 1 are possible by the measures recited in the dependent claims.

It is particularly advantageous if the width of the jaw opening corresponds to at least the width across the flats of the spanner wheel. Thus, at an appropriate position of the spanner wheel, the open-ended spanner can be removed from the screw or nut to be tightened without lateral shifting. By attaching a marking, for example a projecting pin on the spanner wheel, the position of the spanner wheel can easily be detected by a sensor. Especially suitable as a sensor is a contactless initiator which transmits an electrical pulse to an operatingmedia control system as soon as a metal part comes close to it. The drive of the open-ended spanner by a commutating electric motor permits quicker reversal of the direction of rotation compared with a compressed-air motor. Electric motors can be controlled particularly effectively, have minimum reaction times and do not lag when switched off.

Drawing An exemplary embodiment of the invention is shown in the drawing and described in more detail below.

Figure 1 shows a longitudinal section through the open-ended spanner according to the invention and Figure 2 shows a cross-section.

Description of the exemplary embodiment An open-ended spanner 1 has an elongated housing 2. At one end, the housing 2 has a niche 3 which ends in a bore 4. Mounted in this bore is a spanner wheel 5 which, with a preselectable width across the flats, encloses a nut or screw 6 on three sides. For placing against the nut 6, the spanner wheel has a jaw opening 7 which in its width W corresponds to the selected width across the flats. The spanner wheel 5 has a toothing 8 at the periphery. Two gear wheels 11 and 12 mesh with this toothing from two application points 9 and 10 at a distance from one another. The distance A between the application points 9 and 10 is greater than the width W of the jaw opening 7. This ensures that at least one gear wheel 11, 12 always meshes with the toothing 6 during the rotary drive of the spanner wheel 5.Two supporting wheels 13 preferably mounted in ball bearings are arranged in the housing 2 approximately opposite the application points 9, 10.

The gear wheels 11, 12 are both in mesh with a common drive wheel 15 and are driven by the latter. A plurality of drive wheels 16 join the drive wheel 15 inside the handle-shaped housing 2, which drive wheels 16 form a transmission train up to the output wheel 17 of a commutating electric motor (not shown in more detail).

In Figure 2, the housing 2 is shown in a shortened form. Of the drive wheels 16, the frontmost, which is mounted on a pin 19, is visible. The pin sits in opposite bores in the housing 2 and in a housing cover 20. The drive wheel 15 (not shown) and the gear wheels 11 are mounted in a similar manner. On either side, the spanner wheel 5 carries bearing necks 22 which engage in the housing 2 and the housing cover 20 and which in their diameter correspond to that of the bore. The toothing 8 of the spanner wheel 5 projects radially beyond the bearing necks 22 so that the spanner wheel 5 is secured against falling out. Opposite its jaw opening 7, the spanner wheel 5 carries a pin 23 which projects out of one of the bearing necks 22. This pin serves as a marking for the position of the open jaw of the spanner. The position of the pin 23 is sensed by a sensor 24 fastened to the housing 2.The sensor 24 is preferably designed as an initiator acting in a contactless manner. The detecting device for the position of the jaw opening can also be placed at another point of the spanner, as will be described later.

The output wheel 17 of an electric motor, preferably flange-mounted on the housing 2, sits on a shaft 26 which is preferably carried in twin ball bearings. As an alternative to the arrangement in the area of the spanner wheel 5, the detecting device for the position of the jaw opening can likewise be attached to the end of the shaft 26 remote from the motor. This is made possible due to the non-slip transmission train, formed by gear wheels, from the spanner wheel 5 up to the output wheel 17. An element 27 having a lug 28 projecting only in a radial direction on one side is arranged on the shaft 26.

A sensor 29 is attached in the housing 2, and the lug 28 exactly faces the sensor 29 when the spanner 1 is in the open jaw position.

The electric motor acting on the output wheel 17 and also the detecting devices 22, 24, 28, 29 are connected to an operating-media control system (not shown), preferably a programmable control system. Before the start of a screwing operation, the spanner wheel 5 is moved into the position shown in the figures with the jaw opening 7 open towards the niche 3. The motor is switched off after a predeterminable torque is reached. After laterally moving away from the nut or screw 6 to be screwed in, the spanner wheel 5 can be moved into its open position over the shortest route by means of the operating-media control system. In particular both clockwise and anti-clockwise rotation of the spanner wheel 5 is possible without delay. In very restricted space conditions, the open-ended spanner 1, after a predeterminable torque is reached, can also be removed without lateral shifting if the spanner is opened by reverse rotation of the spanner wheel 5.

Claims

1. Motor-driven open-ended spanner (1) having an open spanner wheel (5) which has a friction surface or toothing (8) serving its rotational drive, characterised in that the spanner wheel (5) can be driven from at least two application points (9, 10), in particular via two friction or gear wheels (11, 12), the distance A between which is greater than the width W of the jaw opening (7).

2. Open-ended spanner according to Claim 1, characterised in that the width of the jaw opening (7) corresponds approximately to the width across the flats of the spanner wheel (5).

3. Open-ended spanner according to Claim 1 or 2, characterised in that the two friction or gear wheels (11, 12) driving the spanner wheel (5) interact with a common drive wheel (15).

4. Open-ended spanner according to one of the preceding claims, characterised in that the drive wheel (15) is in turn driven by one or more drive wheels (16) arranged in a row one behind the other.

5. Open-ended spanner according to one of the preceding claims, characterised in that it is driven by a commutating electric motor.

6. Open-ended spanner according to one of the preceding claims, characterised in that a marking (23, 28), in particular a metal pin, is provided in the transmission train between motor and spanner wheel (5, 11, 12, 15, 16, 17), the position of which marking (23, 28) can be detected by a sensor (24, 29) arranged on the housing (2, 20) of the open-ended spanner.

7. Open-ended spanner according to Claim 6, characterised in that the marking is attached to the spanner wheel (5), preferably to its side remote from the jaw opening (7).

8. Open-ended spanner according to Claim 6, characterised in that the marking is attached to the output wheel (17) of the motor or its shaft (26).

9. Open-ended spanner according to one of Claims 6 to 8, characterised in that the sensor (24, 29) is an initiator which detects the marking (23, 28) by a contactless magnetic method and transmits an electrical pulse.

10. Open-ended spanner according to one of the preceding claims, characterised in that its direction of rotation is automatically controlled with regard to the jaw position by an electronic operating-media control system.

11. A spanner substantially as herein described with reference to the accompanying drawings.