US20090170405A1

US20090170405A1 - Assembly for manually grinding a face of a vehicle body part

Info

Publication number: US20090170405A1
Application number: US12/095,791
Authority: US
Inventors: Jerome Barusta
Original assignee: Renault SAS
Current assignee: Renault SAS
Priority date: 2005-12-02
Filing date: 2006-09-20
Publication date: 2009-07-02
Also published as: JP2009517235A; DE602006013697D1; FR2894171A1; FR2894171B1; EP1957236B1; ATE464153T1; WO2007063229A1; EP1957236A1

Abstract

An assembly for manually grinding a face of a motor vehicle body part, including a grinding mechanism, a moving carriage supporting the grinding mechanism, a mechanism to guide the carriage moving along the face to be ground, and a support guide held in position with respect to the body part to be ground. The support guide includes at least one guide face configured to bear at least a first part of the mechanism to guide the moving carriage.

Description

The invention relates to an assembly for manually grinding a face of a vehicle body part.
The invention relates more specifically to an assembly for manually grinding a face of a motor vehicle body part, comprising:

- grinding means rotationally driven by a shaft;
- a moving carriage supporting said grinding means;
- guide means for guiding the moving carriage along the face that is to be ground.

Once various components of a motor vehicle body have been assembled, certain defects may arise associated with the welding or brazing together of the various components of the body, for example between the roof and the body of the vehicle.
When such defects arise, one of the solutions is to strip off the body component that is to be replaced and to bond a substitute component in its place. This solution is the solution generally adopted by aftermarket service centers, but has the disadvantage of requiring a relatively long time for the adhesive to dry.
Another solution is to re-weld a new roof at the works, and call upon the services of a technician who will rectify the face of the vehicle by grinding it or by grinding it down.
The face that is to be ground needs to meet certain criteria. In particular, it needs to have a surface finish, the amount of ripple in which is below a determined value, less than three tenths of a millimeter over a length of the order of half a meter, for example.
In order to meet such precision criteria, the grinding has to be done while exerting pressure uniformly on the face that is to be ground.
Now, it is found that neither a technician, nor anybody else, is capable of meeting the criteria of such precision.
In addition, during manual grinding, there is a risk that a technician will reduce the thickness of the face that is to be ground by too much.
Document U.S. Pat. No. 6,264,534 describes an automated tool for grinding motor vehicles that gets around the lack of precision of a human being. However, this automated tool is expensive and not suited to a garage or an aftermarket service center or even to an in-works rectifying station.
An assembly for manual grinding, described in document U.S. Pat. No. 6,478,663, is also known. This assembly in particular comprises a shaft rotationally and eccentrically driving a grinding disk and which comprises guide means to allow it to travel over the face that is to be ground.
The disadvantage of such an assembly is that the guide means bear only against the face that is to be ground.
On the one hand, this feature means that the face that is to be ground has to be large enough to accommodate the assembly.
On the other hand, the surface that is to be ground in this instance is the only reference upon which the means that guide the assembly bear.
Thus, if the face that is to be ground is deformed and/or deformable, there is a risk that the grinding will not be precise.
It is an object of the invention to propose a solution which is suited, particularly in terms of cost, to use in a garage or in an aftermarket service center and which allows a workpiece, particularly a motor vehicle body part, to be ground manually and precisely.
To this end, the invention proposes an assembly for manually grinding a face of a motor vehicle body part of the type described hereinabove, characterized in that the assembly comprises a support guide which is held in position relative to the body part that is to be ground by positioning means and position-maintaining means, and in that the support guide comprises at least one guide face against which at least a first portion of the guide means that guide the moving carriage is able to bear.
According to other features of the invention:

- a second portion of the guide means that guides the moving carriage is able to bear against the face that is to be ground,
- the grinding means are positioned between the first portion of the guide means bearing against the support guide and the second portion of the guide means capable of bearing against the face that is to be ground,
- the guide face of the support guide extends in a direction substantially parallel to the plane of the face that is to be ground,
- the grinding means are positioned at equal distances from the guide means, in the direction of travel of the moving carriage,
- the moving carriage comprises an element that is axially adjustable in a direction perpendicular to the guide face of the support guide, the purpose of which is to compensate for any lack of coplanarity between the guide face and the face that is to be ground,
- the axially adjustable element of the moving carriage is secured to the first portion of the guide means bearing against the support guide, and serves to adjust the distance between the grinding means and the face that is to be ground in a direction perpendicular to the guide face,
- the guide means that guide the moving carriage comprise guide elements capable of sliding and/or of rolling,
- the guide means that guide the moving carriage comprise a front set of guide elements and a rear set of guide elements which are capable of rolling and have parallel axes.

Other features and advantages of the present invention will be better understood from the description and from the attached figures among which:

FIG. 1 is a schematic front view in cross section depicting a manual grinding assembly according to a first embodiment of the invention and a face that is to be ground belonging to a motor vehicle body;

FIG. 2 is a detailed front view of FIG. 1 on a larger scale;

FIG. 3 is a detailed side view depicting the manual grinding assembly of FIG. 1;

FIG. 4 is a detailed view from above depicting the manual grinding assembly of FIG. 1;

FIGS. 5 a and 5 b are diagrams illustrating the impact of the longitudinal separation of the guide means bearing against a curved face;

FIG. 6 is a schematic perspective view depicting the manual grinding assembly according to a second embodiment of the invention, together with the face that is to be ground of the motor vehicle body.

In the description which follows, which is given by way of nonlimiting indication, components that are identical, analogous or similar will be denoted by the same reference symbols.
In the description and the claims, a longitudinal, vertical and transverse orientation indicated by the L, V, T trihedral frame of reference marked in the figures will be adopted by way of nonlimiting example.
FIG. 1 depicts an assembly 10 for manual grinding comprising grinding means 30 supported by a moving carriage 32. The moving carriage 32 comprises guide means 34 allowing it to be moved along a face 14 that is to be ground belonging to a motor vehicle body part 12, for example by a technician.
The face 14 that is to be ground is substantially planar or has a radius of curvature, and has a bead 16 of braze or weld material to be ground and which in this instance extends in a horizontal plane that is substantially longitudinal in the figures.
According to the invention, the assembly 10 comprises a support guide 18 comprising a guide face 20 against which a first portion 34 a, 34 b of the guide means 34 that guide the moving carriage 32 bears.
The support guide 18 is held in position relative to the vehicle body 12 by positioning means 26 a, 26 b and position-maintaining means 22.
The positioning means 26 a, 26 b for positioning the support guide 18 comprise a planar first face 26 a in linear contact with a substantially convex curved face 28 a of the body 12. The positioning means 26 a, 26 b have a planar second face 26 b bearing flat against a substantially planar face 28 b, such as a face of a body pillar, for example.
In addition, the support guide 18 comprises means 22 of attachment relative to the body 12, which may consist of any known attachment means.
However, attachment preferably involves at least two screws 22 which pass through, or nip the face 28 b of the body 12 and which are screwed into tapped holes 24 of the support guide 18.
An arrangement such as this allows the support guide 18 to be positioned and kept in position relative to the body 12 and allows the guide face 20 to offer a plane that is substantially parallel to the plane of the fact 14 that is to be ground.
Advantageously, the support guide 18 is made of a strong material, such as steel or aluminum, or high-density resin, to guarantee the rigidity and non-deformation of the guide face 20.
The guide means 34 that guide the moving carriage 32 here comprise four wheels 34 a, 34 c, 34 d which may also be ball or roller bearings, and each of which is free to rotate about a transverse axle 37. Advantageously, the transverse axles 37 are screws.
According to a first embodiment of the invention, the guide face 34 and the face 14 that is to be ground are substantially planar.
According to this first embodiment, one pair of wheels 34 a, 34 b bears against the guide face 20 of the support guide 18 and another pair of wheels 34 c, 34 d bears against the face 14 that is to be ground.
Thus, the moving carriage 32 comprises a left pair of wheels 34 a, 34 b bearing against the guide face 20 and a right pair of wheels 34 c, 34 d bearing against the face 14 that is to be ground, as illustrated in particular in FIG. 4.
By way of nonlimiting example, the moving carriage 32 may have just one right wheel 34 d, in which case this wheel is positioned substantially at equal distances from the two left wheels 34 a, 34 b in a longitudinal orientation.
Of these four wheels 34 a, 34 b, 34 c, 34 d, two wheels 34 a, 34 c are positioned at the front of the moving carriage 32 and two wheels 34 b, 34 d are positioned at the rear of the moving carriage 32, on transversely oriented, parallel axes B1, B2.
The moving carriage 32 is a rigid structure with the overall shape of an upside-down U. the moving carriage 32 has a left side upright 36 a and a right side upright 36 b in which uprights the axles 37 about which the left wheels 34 a, 34 b and the right wheels 34 c, 34 d are respectively positioned.
The two side uprights 36 a, 36 b extend in a longitudinal plane perpendicular to the guide face 20 and are joined together by a plate 38 parallel to the guide face 20.
Advantageously, the left side upright 36 a is an element that can be adjusted axially relative to the plate 38 in a direction perpendicular to the guide face 20. Thus it is possible to alter the axial height of the left wheels 34 a, 34 b, which is secured to the upright 36 a, and compensate for any clearance “j” there might be between the guide face 20 and the face 14 that is to be ground, as can be seen in FIG. 2.
To this end, the left side upright 36 a has a sliding connection to the plate 38.
The sliding connection is afforded by a vertical groove 44, positioned in the left side upright 36 a, and capable of sliding along a vertical slide 46 which projects transversely from the left side edge 41 of the plate 38, as depicted in FIG. 4.
The left side upright 36 a comprises two vertical oblong holes 39 through which there pass transversely two screws 40 which are screwed into a left side edge 41 of the plate 38, in order to keep the left side upright 36 a in position relative to the plate 38.
The plate 38 and the right side upright 36 b of the moving carriage 32 are attached using two vertical screws 42.
Without implying any limitation, the plate 38 and the right side upright 36 b may be welded together, brazed together, or formed as a single piece.
The grinding means 30 positioned in the moving carriage 32 comprise a body 44 equipped with drive means, such as a motor (not depicted).
The body 44 is connected to an upper end of a shaft 48 rotationally driven about an axis A which is generally perpendicular to the guide face 20. The shaft 48 has a lower end connected to a disk 46 comprising an abrasive “active” portion 47 the plane of which runs parallel to the guide face 20.
The “active” portion 47 here lies flush with the right wheels 34 c, 34 d in the plane of the points of contact between the right wheels 34 c, 34 d and the face 14 that is to be ground, and is therefore capable of grinding the bead of weld material 16 on the face 14 of the body 12.
the body 44 of the grinding means 30 here is of substantially cylindrical shape with axis A and is positioned coaxially along the axis A in a bore 50 in the plate 38 of the moving carriage 32.
The bore 50 may comprise means of tightening it onto the body 44 to prevent the latter form turning during grinding.
To this end, the bore 50 is equipped with a radial slot 52 which opens to the outside in a boss 53. Passing transversely through this boss is a screw 54 which can be used to make the slot 52 narrower or wider and therefore allows the bore 50 to be tightened around the body 44 by nipping, of slackened off. An arrangement such as this also allows the height of the grinding means 30 to be adjusted to suite the reduction in thickness of the bead 16 of weld material resulting from a previous grinding operation.
Advantageously, the grinding means 30 are removable and may be an electric or pneumatic manual grinding machine 30 known from the prior art. Likewise, the plate 38 is capable of accepting various types of grinding machine 30.
According to an alternative form of the first embodiment, illustrated in FIGS. 5 a and 5 b, the face 14 that is to be ground has a substantially curved profile that is convex about a transverse axis.
In this case, the guide face 20 has substantially the same convex curved profile as the face 14 that is to be ground, so that the left wheels 34 a, 34 b bearing against the face 20 and the right wheels 34 c, 34 d bearing against the face 14 that is to be ground, follow similar curved parts.
In addition, the curvature of the face 14 gives rise to a level-offset “d1”, along the axis A, between the wheels 34 a, 34 b, 34 c, 34 d and the abrasive active part 47 of the disk 46, as illustrated in FIG. 5 a.
A level-offset “d1” such as this is disadvantageous because it may cause the abrasive disk 46 to grind too deeply into the face 14 that is to be ground.
In order to limit or avoid this disadvantage, the level-offset “d1” is reduced to a smaller level-offset “d2” by moving the wheels 34 a, 34 b, 34 c, 34 d closer together from a separation “e1” to a shorter separation “e2” in a longitudinal direction, as depicted in FIGS. 5 a and 5 b.
In addition, the grinding means 30 are advantageously positioned at equal distances from the front wheels 34 a, 34 c and rear wheels 34 b, 34 d in the longitudinal direction so that the axis A of rotation of the shaft 48 is substantially parallel to the normal to the portion of face 14 in the process of being ground.
According to yet another alternative form (which has not been depicted) of the first embodiment of the invention, the assembly 10 comprises a device for axially adjusting the grinding means 30 relative to the wheels 34 a, 34 b, 34 c, 34 d, in the direction perpendicular to the guide face 20.
According to a second embodiment depicted in FIG. 6, the guide means 34 bear only against the guide face 20 of the support guide 18. This embodiment allows the guide means 34 that guide the moving carriage 32 to bear against a single reference face 20 and thus makes it possible to overcome completely the effects of any geometric defects of the face 14 that is to be ground.
By way of nonlimiting example, the guide means 34 may comprise a bearing free to effect a translational movement along shafts positioned parallel, shoes capable of sliding over the guide face 20, or any other element capable of rolling and/or of sliding.
Likewise, the assembly 10 according to the invention can be used on various parts of a motor vehicle body.
Finally, the grinding means may comprise a grinding wheel or a milling cutter or any other rotationally driven cutting element.

Claims

1-9. (canceled)

10. An assembly for manually grinding a face of a motor vehicle body part, comprising:

grinding means rotationally driven by a shaft;

a moving carriage supporting the grinding means;

guide means for guiding the moving carriage along a face that is to be ground; and

a support guide held in position relative to a body part that is to be ground by positioning means and position-maintaining means, and wherein the support guide comprises at least one guide face against that at least a first portion of the guide means that guides the moving carriage is able to bear.

11. The assembly for manual grinding as claimed in claim 10, wherein a second portion of the guide means that guides the moving carriage is able to bear against the face that is to be ground.

12. The assembly for manual grinding as claimed in claim 11, wherein the grinding means is positioned between the first portion of the guide means bearing against the support guide and the second portion of the guide means able to bear against the face that is to be ground.

13. The assembly for manual grinding as claimed in claim 10, wherein the guide face of the support guide extends in a direction substantially parallel to the plane of the face that is to be ground.

14. The assembly for manual grinding as claimed in claim 10, wherein the grinding means is positioned at equal distances from the guide means, in the direction of travel of the moving carriage.

15. The assembly for manual grinding as claimed in claim 10, wherein the moving carriage comprises an element that is axially adjustable in a direction perpendicular to the guide face of the support guide.

16. The assembly for manual grinding as claimed in claim 15, wherein the axially adjustable element of the moving carriage is secured to the first portion of the guide means bearing against the support guide.

17. The assembly for manual grinding as claimed in claim 10, wherein the guide means that guides the moving carriage comprises guide elements capable of sliding and/or of rolling.

18. The assembly for manual grinding as claimed in claim 10, wherein the guide means that guides the moving carriage comprises a front set of guide elements and a rear set of guide elements that are capable of rolling and that have parallel axes.