WO2007039601A1

WO2007039601A1 - End piece for screwing and tightening a fixing element of a tubular member to a support and corresponding screwing device

Info

Publication number: WO2007039601A1
Application number: PCT/EP2006/066983
Authority: WO
Inventors: Nicolas Le Du
Original assignee: Etablissements Georges Renault
Priority date: 2005-10-04
Filing date: 2006-10-03
Publication date: 2007-04-12
Also published as: FR2891487A1; FR2891487B1

Abstract

The invention relates to an end piece which is used to screw a fixing element (1) of a tubular member (2) to a support. The invention comprises a drive head (4) and a collet (3) which is intended to co-operate with the fixing element (1), said collet (3) being equipped with a slot forming a passage for the tubular member (2). According to the invention, the drive head (4) and the collet (3) are essentially coaxial and are connected by means of an intermediate body (5) which is offset partially in relation to the axis of rotation of the drive head (4) and the collet (3). The invention is characterised in that the intermediate body (5) comprises transmission means with reduction gearing for transmitting the rotational movement of the drive head (4) to the collet (3). The inventive end piece also comprises means for controlling a tightening torque transmitted by the collet (3).

Description

Screwing and tightening end of a fastener element of a tubular member on a support, and corresponding screwing device.

The field of the invention is that of industrial equipment. More specifically, the invention relates to a tip and a screwing technique of a fastener member of a tubular member.

The invention is particularly, but not exclusively, intended for screwing internal combustion engine injectors.

These injectors comprise a pipe generally having, at each of its ends, fastening elements, such as nuts, and which are free to rotate around the ends of the pipe.

Currently, to ensure the attachment of the injectors, two tools are successively used.

At first, the nuts are screwed using a pneumatic clamp on which is mounted a nozzle. This tip is mounted on the angle head of the screwdriver and includes a housing extending in a plane perpendicular to the axis of rotation of the corner head. The free end of the endpiece has a screwing bushing having a housing which is open, on the one hand radially to allow the passage of the feed pipe of the injection and, on the other hand, axially downwards to allow the introduction of the male upper part of the nut which is received in the female housing complementary shape of the sleeve.

The casing incorporates a gear cascade arranged in such a way that the rotary drive axis of the driving head, on the one hand, and the axis of rotation of the screwing bushing, on the other hand, are two parallel axes, separated by the housing.

The gear cascade has a variable efficiency in terms of transmission of motions.

Consequently, the screwing, during this first phase, is performed with a low level of torque, the tip of the tool as described previously not allowing sufficient accuracy to effect the final tightening of the injector nuts.

This final tightening is then operated in a second time, with the aid of a second tool consisting of an electric clamping machine provided with a split sleeve connected by a rollbar to the drive square of the head of the clamp.

More specifically, this tool comprises a tip comprising a drive head and a clamping sleeve connected by an intermediate body

(The hoop), the driving head and the sleeve being coaxial and the intermediate body being axially offset relative to the drive head and the sleeve.

With this type of tooling, the tightening must be performed on an angular stroke less than 360 ° due to the presence of the injector pipe which forms an obstacle to the rotation of the intermediate body.

The stroke of the intermediate body therefore involves the abutment thereof on either side of the injection pipe and the implementation of means for measuring the angle traveled by the body.

However, the contact between the hoop and the injector tube must not take place for two reasons: the accuracy would be disturbed and there is a risk of damaging the injector tube. In any case, the screwing and tightening of the injector nuts have a major drawback: they require the use of two separate tools, which, in practice, is manifested by loss of time, tooling costs, logistical heaviness ...

The invention particularly aims to overcome the disadvantages of the prior art.

More specifically, the invention aims to provide a tool that allows the screwing and tightening of a fastener member of a tubular member on a support in a reduced time compared to the prior art.

The invention also aims to provide such a tool that allows the screwing and tightening with a single tool. The invention also aims to provide such a tool that allows the screwing and tightening with a single tool in a single operation and continuously.

Another object of the invention is to provide such a tool that is simple in design, easy to implement and inexpensive to produce.

These objectives, as well as others which will appear later, are achieved thanks to the invention which relates to a screwdriver bit of a fastener element of a tubular member on a support, comprising a drive head and a clamping bush intended to cooperate with said fastener element, said bushing having a slot forming a passage for said tubular member, said drive head and said bushing being substantially coaxial and connected by an intermediate body at least partially offset with respect to the axis of rotation of said drive head and said bushing, characterized in that said intermediate body comprises transmission means with reduction of a rotational movement of said drive head to said bushing, said nozzle comprising means for controlling a tightening torque transmitted by said sleeve.

In this way, a tool is obtained to effect the tightening and tightening of the fastening element of a tubular member, such as an injection nut. Indeed, the transmission means of the rotational movement of the drive head to the socket, allow to perform the screwing while the intermediate body is fixed, while ensuring the coaxiality between the drive head and the sleeve.

In addition, as will become clearer later, these transmission means implemented in the intermediate body can be designed to ensure good accuracy. This provides a tip having a satisfactory accuracy to achieve an effective and adjusted tightening under control.

In fact, because of the internal reduction in axis return, the measured torque is: Sensor Torque = Torque Torque - Motor Torque

= Tightening torque x (l-l / (reduction ratio x efficiency))

However, in the case of a conventional axis return, the performance error applies to 100% of the torque measured by the sensor, whereas in this case, this error applies to a fraction of the torque measured, fraction as much lower as the reduction ratio is high.

According to an advantageous solution, said transmission means comprise a first stage cooperating with said drive head and a second stage cooperating with said bushing, at least one of said first or second stage preferably comprising means for reducing said rotational movement.

According to a preferred embodiment, said reduction between said drive head and said bushing is about 1/9, each of said first or second preferably comprising reduction means of about 1/3. As already mentioned, the lower the reduction ratio, the lower the error applied to the measured torque. Thus, with a ratio of 1/9, if the efficiency of the transmission means varies between 85% and 95%, the multiplicative factor between the tightening torque and the measured torque varies by approximately 1.6% against 10% with a reference. conventional axis. In addition, the reduction ratio of 1/3 on each floor makes it easy to maintain coaxiality between the drive head and the bushing.

The output gear having a radial opening for the passage of the injector tube, it is expected that it is driven by two gears. When one of the two gears passes through the radial opening, the other continues to drive the output gear (this implies that there is not necessarily equal reduction ratios between the top tier and the bottom).

According to an advantageous solution, said intermediate body comprises a casing inside which said transmission means are mounted, said casing extending inside said drive head, coaxially with it. In this case, said control means preferably comprise at least one torque sensor mounted on said housing, inside said drive head.

According to an advantageous solution, the device comprises shock absorption means that can be exerted on said intermediate body.

Thus, it is possible to limit or even eliminate the errors in measuring the tightening torque when the support of the socket on the fastening element is not exerted coaxially with the socket due to possible shocks.

In this case, said shock absorbing means preferably comprise at least one needle cage interposed between said housing and said drive head.

The invention also has a screwing device equipped with a screwdriver bit of a fastener element of a tubular member on a support, comprising a drive head and a clamping sleeve intended to cooperate with said fixing element. said bushing having a slot forming a passage for said tubular member, said driving head and said bushing being substantially coaxial and connected by an intermediate body at least partially offset from the axis of rotation of said driving head and said bushing, characterized in that said intermediate body comprises transmission means with reduction of a rotational movement of said drive head to said bushing, said bit comprising means for controlling a tightening torque transmitted by said bushing .

Other features and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment of the invention, given by way of illustrative and nonlimiting example, and the appended drawings among which:

FIG. 1 is a view of a screwing device equipped with a screwdriver bit according to the invention; FIG. 2 is a view of a tabular member of the type of those whose screwing is ensured by means of a screwing device equipped with a screwdriver bit according to the invention.

Referring to Figure 2, a screwing device equipped with a nozzle according to the invention is used for fixing a tabular member such as an injector pressurized fuel internal combustion engine.

Such fuel injectors have at least at their ends a fastening element, such as a nut 1 which is integral with a pipe 2, intended to be screwed on the cylinder head of the engine, and which is rotatably mounted around the end of the pipe 2.

The device according to the invention illustrated in FIG. 1 comprises a socket 3 having a housing which is open, on the one hand radially to allow the passage of the supply pipe of the injector and, on the other hand, axially towards the bottom to allow the introduction of the male upper part of the nut which is received in the female housing complementary shape of the sleeve.

The device also comprises a driving head 4 coupled to the bush 3 by an intermediate body 5. The driving head 4 and the bushing are coaxial and the body 5 comprises a connecting part offset with respect to the rotation of the driving head 4 of the sleeve 3.

According to the principle of the invention, transmission means integrated in the intermediate body rotate together the drive head 4 and the sleeve 3 and allow to perform a tightening with a controlled torque.

To do this, according to this embodiment, the intermediate body 5 incorporates two transmission stages: a first stage comprising a pinion 51 carried by the end of a shaft 52 and cooperating with a pinion 41 carried by the shaft 42 the driving head 4; a second stage comprising a pinion 53 carried by the other end of the shaft 52 and cooperating with the sleeve 3. Preferably, the reduction ratio between the pinion 51 and the pinion 41, as well as that between the pinion 53 and the socket, is 1/3, providing an overall reduction ratio between the driving head 4 and the socket 3 of 1/9.

Of course, other reduction ratios can be implemented in other conceivable embodiments, having already been specified that the higher the reduction ratio, the more accurate the device.

As it appears, the intermediate body 5 comprises a casing 54 in which are integrated the sleeve 3, the pinions 51, 53 and the shaft 52, and the pinion 41 of the drive head. Torque control means applied to the socket are measured on the housing 54, a torque sensor being mounted on the extension 541 of the housing.

In addition, according to the present embodiment, a needle cage 7 is interposed between the extension 541 of the casing and the wall 43 of the drive head, this cage to absorb any shocks likely to be exerted on the intermediate body 5.

It should also be noted that, in a manner known per se, the split bushing is provided with a device for reindexing (not shown) the opening so that, after tightening and releasing the bushing of the nut, the reverse rotation is actuated and the bushing stops in a position such that its opening allows the passage of the tube to clear the clamp.

Claims

1. End piece for screwing a fastening element (1) of a tubular member (2) on a support, comprising a driving head (4) and a clamping sleeve (3) intended to cooperate with said element of fastener (1), said bushing (3) having a slot forming a passage for said tubular member, (2) said driving head (4) and said bushing (3) being substantially coaxial and connected by an intermediate body (5) offset at least partially relative to the axis of rotation of said drive head (4) and said bushing (3), characterized in that said intermediate body (5) comprises transmission means with reduction of a movement of rotation of said driving head (4) to said bushing (3), said endpiece comprising means for controlling a tightening torque transmitted by said bushing (3).

2. Screw bit according to claim 1, characterized in that said transmission means comprise a first stage cooperating with said drive head (4) and a second stage cooperating with said sleeve (3).

3. Screw bit according to claim 2, characterized in that at least one of said first or second stage comprises means for reducing said rotational movement.

4. Screw bit according to any one of claims 1 to 3, characterized in that said reduction between said drive head (4) and said sleeve (3) is about 1/9.

5. Screw bit according to claims 3 and 4, characterized in that each of said first or second stage comprises reduction means of about 1/3.

6. Screw bit according to any one of claims 1 to 5, characterized in that said intermediate body (5) comprises a housing (54) within which are mounted said transmission means, said housing extending to the interior of said driving head (4) coaxially with it.

7. Screw bit according to claim 6, characterized in that said control means comprise at least one torque sensor (6) mounted on said housing (54), inside said drive head (4).

8. Screw bit according to any one of claims 1 to 7, characterized in that it comprises shock absorption means may be exerted on said intermediate body (5).

9. Screw bit according to claim 8, characterized in that said shock absorbing means comprise at least one needle cage (7) interposed between said housing (54) and said drive head (4).

10. Screwing device equipped with a screwdriver bit of a fastener (1) of a tubular member (2) on a support, comprising a driving head (4) and a sleeve (3) clamping intended to cooperate with said fixing element (1), said sleeve (3) having a slot forming a passage for said tubular member, said drive head and said sleeve being substantially coaxial and connected by an intermediate body (5) offset at least partially in relation to the axis of rotation of said drive head (4) and said bushing (3), characterized in that said intermediate body (5) comprises transmission means with reduction of a rotational movement of said driving head (4) to said bushing (3), said endpiece comprising means for controlling a tightening torque transmitted by said bushing (3).