GB2067760A - A method for measuring, controlling and marking-off parts, and a universal machine for practicing the method, and its application to the manufacture of car body parts - Google Patents

Abstract

Templates are made to correspond to reference sections of a part to be controlled. Each template (19) is successively assembled to a support head (18) mounted at the end of an arm (17) movable along three coordinate axes. For being movable along one of the coordinate axes the machine comprises an arm of a fixed length and supported by a carrier (21) to which said arm is connected via a fulcrum (20) and locking means (22), said arm comprising at its free end a tool-holder head (18) to which it is connected via a location trim compensation support (32). <IMAGE>

Description

SPECIFICATION A method for measuring, controlling and marking-off parts, and a universal machine for practicing the method, and its application to the manufacture of car body parts The present invention relates to a method for controlling the manufacturing tolerances of parts, the method being usable also for some markingoff operations of said same parts.

Machines have already been proposed which comprise measuring and eventually marking-off points which are carried by an arm so as to be moved along three coordinate axes. Some of said machines comprise even programming and servocontrol means allowing the control by means of the point carried by the head of the location of characteristic portions of a part which has been manufactured or is being manufactured.

Such machines are indispensable, particularly in the automobile industry where a very careful control of many parts of the car body is necessary, and also portions of the vehicle which are already partly or totally assembled.

Amongst the documents of the prior art technique relating to machines of this type, German publication No. 2 71 5 1 75 discloses a machine displaceable along the three coordinate axes and comprising adjusting means for the feeler head so that said head may have its location trim regulated. However, the feeler device is mounted on an arm the useful length of which is variable, thereby rendering necessary continuous adjustments of a deflection compensation device and which therefore does not ensure that the useful portion of the feeler member can always occupy a perfectly definite position in space.

British patent No. 1 452 280 had disclosed another machine of the type where the measuring head comprises a feeler 2 displaceable along the three coordinate axes and wherein moreover the member 2 can be turned to various positions.

However, there again, one cannot be sure that the position in space of the working portion of the feeler member is defined in a perfectly precise manner.

U.S. patent No. 3 678 584 discloses a measuring unit which in fact is provided for enabling the feeler member to occupy various positions by rotating about two axes positioned at 450 one relative to the other. In this arrangement which uses an articulated bent arm, the overhanging length is modified according to the position of the articulated bent arm and, by way of consequence, an error is thus introduced which is due to a change of the deflection of the overhanging members.

The present invention provides a new method and a machine for practicing the method, which simplifies considerably the checking and control operations while allowing various marking-off operations. Moreover, the machine of the invention can very simply comprise a large member of control, measuring and making-off tools, said tools being nevertheless always in a position which is practically ideal relative to the theoretical position which they have to occupy, and this even when the tool weights are substantially different.

According to the invention, the method for controlling various parts, particularly parts of a car body, is characterized in that a set is made of templates corresponding to reference sections of a part to be controlled, and wherein each template is successively assembled to a support head mounted at the end of an arm movable along three coordinate axes.

According to another important feature of the invention, the inclination of the arm as well as that of the template positioned at the end of the arm is set as a function of its weight so that each template is initially in a same reference position in space.

For practicing the hereabove method, the invention creates a machine which comprises at least a unit having the function of a surface-plate for the part and at least one support unit for a head selectively displaceable along the three coordinate axes, machine which is characterized in that it comprises for being movable along one of the coordinate axes, an arm of fixed length carried by a carrier to which said arm is connected via a fulcrum and locking means, said arm comprising at its free end a tool-holder head to which it is connected via a location trim compensation support.

Various further features of the invention will become more apparent from the following detailed description of embodiments of the object thereof, given by way of examples and non limitative, with reference to the accompanying drawings wherein: Figure 1 is a partial perspective and partial diagrammatic view of a measuring machine practicing the invention.

Figure 2 is a partial elevation view of the measuring arm shown on the machine of Figure 1.

Figure 3 is an enlarged partial elevation view of a detail af Figure 2.

Figure 4 is a cross-sectional view substantially along line IV--IV of Figure 2.

Figure 5 is a perspective view of the measuring arm head of Figures 1 and 2; Figure 6 is a side elevational view of the measuring head of the preceding Figures and of members for its support, shown in cross-section; Figure 7 is a partly cross-sectional top view of the support of the measuring head; Figure 8 is a side elevation view of the head support of the preceding Figures; Figure 9 is a cross-section of the control excenter of the head support of Figure 8; Figure 10 is a partly cut out front view of the head shown in Figure 6; Figure 11 is an elevational cross-sectional view explaining a group of members shown in Figures 5 and 6; Figure 12 is a partial top plan-view of the measuring head of Figure 6; Figure 13 is a sectional view along line Xlll-Xlll of Figure 12;; Figure 14 is a diagrammatic elevational view in cross-section of a tool-holder for the measuring head of the preceding Figures; Figure 1 5 is a partly diagrammatic perspective view of the measuring head when applied for the presentation of control templates; and Figure 16 is an explanatory elevation view showing another application of the invention.

Referring now to the drawings, Figure 1 shows a measuring and control machine according to the invention, which comprises a pit 1 on either side of which are disposed two co-planar half surfaceplates 2, 2a. The half surface-plates 2, 2a support the body 3 of a vehicle through machined and calibrated supports 4 for providing an access from underneath the vehicle. Two measuring assemblies 5, 5a are respectively disposed on either side of the half surface-plates, these measuring assemblies being mounted on base plates 6 in alignment with said half surface-plates.

The two measuring assemblies are identical and, consequently, one only of them will be described herebelow.

The measuring assembly 5 comprises a carrier 7 displaceable on the base-plate 6 along the x axis. The carrier 7 is driven by an electrical motor 8 and protection bellows 9, 9a protect the guiding slides carried by the base-plate 6. The carrier 7 supports a vertical column 10 extending along the z axis and comprising guides 11 for a slider 12, this slider being driven by a screw 13 and a motor 14. The slider 12 protrudes on either side of the column 10 and extends to the vicinity of the half surface-plate 2a, and its center of gravity is situated in a plane passing approximately half way between the guides 11 so that said slider does not tend to tilt and that fittings or bearings 1 4a which bear on the guides 11 are only slightly loaded.

Bellows (not shown) also protect the hereabove described members.

The slider 12 comprises slides which are not shown in the drawing for the horizontal carrier 15 driven by a motor 16 and, consequently, the carrier 1 5 is movable along the y axis.

The carrier 15 supports an arm 17 overhanging beyond the carrier 15 for forming a constant length bracket. The arm 17 is provided at its free end with a head 18 for supporting a removable tool 19.

As appears from the foregoing, the tool 19 can be displaced according to the three coordinate axes x, y and z by the displacement of the hereabove described carrier and slider.

The machine comprising two measuring assemblies 5, 5a, the measurements carried out on a part, for instance the body of a vehicle 3, may be effected symmetrically and when the vehicle is carried on calibrated supports 4 connecting the half surface-plates 2, 2a, the measurements and controls may be effected as well on the lateral sides as on the top and bottom of the vehicle.

The arm 17 being overhanging, it has necessarily a deflection which is constant whatever the position occupied by said arm, provided the tool 19 is not changed. On the contrary, as soon as the tool 1 9 is changed and the new tool mounted has a different weight, the deflection varies so that the head 18 describes an arc of a circle which has to be connected for bringing back the head at a correct reference level and, moreover, the modification of the location trim of the head 18 has to be carried out so that all the reference conditions in space are reestablished before proceeding to a control or a marking-off operation.

For reestablishing the reference level of the head and the arm 17, Figures 2 and 3 show that the carrier 1 5 is provided with a fulcrum 20 on which is articulated a plate 21 which can be locked in its various positions by means of clamp bolts 22 extending through buttonholes 23 and operable by means of levers 24. The plate 21 carries at one end an inclined ramp 25 (Figure 2) on which may be moved a roller 26 (Figures 2 and 3) carried by a carrier 26a axially displaceable by a socket and screw device 27 controlled by a knurled knob 27a. The socket and screw device has a mark 28 movable in front of a scale 29. The hereabove described assembly is carried by a support 30 fixed on the carrier 15.Thus, when the head 18 has to be brought back to the reference level, it suffices to act on the levers 24 for pivoting the piate 21 on the fulcrum 20 and then, with the knob 27a, one moves the roller 26 along ramp 25.

The scale 29 may be for instance graded as a function of the weight of the tools which can be carried by the head 8 and, on the other hand, the same is provided with a marking gauge 31 (Figures 5, 7 and 10) placed opposite markings provided for instance on the slider 12.

For adjusting the location trim of the head 1 8, the head 1 8 is connected to the arm 1 7 via a support designated as a whole by reference numeral 32. The support 32 is connected by a flange 33 to a complementary flange 34 rigid with the end of arm 17. The flange 33 supports iron fittings 35 forming wings 36 (Figures 5 and 7) of which the front face which is directed towards the head 18 is of an arcuate shape. The wings 36 form supports for covers 37 having a front edge 38 also of an arcuate shape and used for guiding at the same time as the arcuate edge 36 has shoes 39 carried by the sides 40a, 40b of a stirrup 40.

The stirrup sides comprise a bottom 41 having ends supporting square members 42, 43 of which a wing is provided with buttonholes 44 (Figures 6 and 7).

The side of the square members 42, 43 having a buttonhole 44 is engaged in a groove 45 of the iron fitting 35 (Figures 5 and 7) and bears against one of the sides of this groove. Screws 46 and 47 are provided for extending through the cover 37 and the buttonhole of the square members 42, 43 and for being screwed in the iron fitting 35. Thus, when the screws 46 and 47 are screwed, they apply the branch of the square members against the iron fitting 35, thereby making the stirrup 40 rigid with the iron fitting 35 and, by way of consequence, the flange 34 of the arm 1 7.

Figures 5, 8 and 9 show that the cover 37 which has an arcuate front edge 38 has a hole 48 for a spindle 49 prolongated by an excenter 50 extending into a blind hole 51 of the shoe 39 carried by the side 40a of the stirrup. A plate 52 rigid with the axis 49 has an arcuate opening 53 in which passes a locking screw 54. When the screws 46, 47 are unscrewed, it is possible to turn the plate 52 and, by way of consequence, the excenter 50 moves the shoes 39 and therefore the stirrup 40 relative to the wings 36 and the covers 37, 38. Consequently, the location trim of the stirrup 40 and therefore of the head 1 8 is modified relative to the end of the arm 17.

The adjustment of the location trim is controlled by the gauge 31 and, in case, by markings which may be provided on the one hand on one of the stirrup 40 sides and on the other hand on one of the covers 37 or 38.

Figure 6 shows that the bottom 41 supports a socket 55 in which are provided bearings 56, 57 forming thrust bearings, in which is mounted the thinned out shank 58a of a spingle 58. The end of the shank 58a is threaded as is shown at 58b and a nut 59 is screwed on said end for bearing against the thrust bearing 57. Thus, the shank 58a is constrained between the bearings 56 and 57 so that there is no play.

The axis 58 extends through a slit ring 60 fixed by a screw 61 to a pillow 62 fixed in turn to the stirrup 40.

Figure 11 shows also said slit ring 60 one branch of which is tapped and receives a threaded end 63 of a rod 64 mounted in a sheath 65 guided in a socket 66 fixed to the stirrup side 40a, the sheath 65 being formed with a milled hole 67 for operating the rod 64 and the screw 63. Figure 11 shows that the sheath 65 bears against the second branch of the slit ring 60. Thus, by rotating the sheath 65, the screw 63 is being screwed, which presses the slit ring 60 against the spindle 58 by immobilizing it relative to the stirrup 40. The position of the sheath 65 appears clearly in Figure 5 just behind the stirrup 40. The spindle 58 supports the measuring head 18.The head 18 comprises a fly-wheel 68 in which are provided notches 69 for housing a catch 70 {Figures 5, 6 and 7) for immobilizing the fly-wheel 68 in socalled preferential positions, for example four positions off-set by 900. Moreover, markings 71 and a vernier 72 are respectively provided on the one hand on the fly-wheel 68 and on the other hand on the stirrup, as shown in Figure 8.

These markings and vernier enable locking the fly-wheel with a high precision, and therefore the measuring head 18, by rotating the axis 58 which is then locked by the slit ring 60 as explained hereabove. It is remarkable to see that by using a slit ring for the locking operation, any stray movement of the spindle is avoided when the measuring head has been brought to the chosen angular position and, moreover, a slit ring does not risk to damage axis 58.

The fly-wheel 68 carries two flanges 73, 74 forming plates 75, 76 supporting a spindle 77 extending through holes 78, 79 (Figure 13) and lockable in any position by a slit ring 80 fixed by a bolt 81 on the plate 75. The slit ring 80 is made as previously described with respect to ring 60. The spindle 77 is mounted on two pillows 82, 83 interposed between plates 75, 76 and a core 84, and the portion of the spindle 77 extending through the core 84 has a small diameter.

The drawings show that the core 84 is cylindrical but has flat portions 86. As a matter of fact, it could assume another shape, for example a square shape. The core 84 is fixed to the pillows 82, 83 by dowels 85 or similar in order to be able to turn.

Markings 87 and a vernier 88 are respectively provided on the plate 76 and the pillow 82 (Figures 10 and 13) in order to know with precision the angular position of the core 84. Two bores 89, 90 are provided in the core at right angles and extending from one side to the other.

The plate 76 has a hole 91 (Figure 10) for a socket 92 in which is engaged a dowel 93 which can be operated via a screw 94 and a knurled knob 95. The dowel 93 is intended for being engaged in one or the other of two holes 96 or 97 (Figure 12) at 450 one relative to the other. Thus, the mouths of the bores 89 and 90 can occupy positions which are marked and separated from each other by 450; all the intermediate positions being besides possible by lifting the dowel 93 which can, on the other hand, be locked by means of a key 98 formed by a small plate engaged in a groove (not shown) of the dowel 93 and fixed by screws 99 on the plate 76.

The bores 89, 90 are used for the positioning of measuring and/or marking-off tools which may be fixed directly or by means of a tool-holder.

Figure 14 shows an advantageous embodiment of a tool-holder enabling in particular the machine to comprise measuring templates.

The tool-holder comprises a plate 100 on one side of which protrudes a support plate 101 corresponding to the flat portion 86 and beyond which is formed a centering ring 102 which can enter with an easy fit one of the bores 89 or 90.

The centering ring is extended by an expansion socket 103 formed with longitudinal slots 104.

A conical head screw 105 is provided for being screwed in the ring 102 in order to spread out the portions of socket 103 by pressing them inside the bores 89 or 90.

The plate 100 comprises also at least one locking screw 106 which can be screwed in one of the tappings (not shown) of the core 84 if required. Likewise, the core is formed, as shown in Figure 10, with millings 107 extended by tappings 108 for cone point set screws or similar.

When one considers again Figure 14, and on the other side of the plate 100, the tool-holder comprises a plate 109 the face 1 09a of which is plane and in alignment with the axis of the ring 102, so that one is ensured that the prolongation of the axis of bores 89 or 90 extend in the plane of the face 1 09a.

Centering studs 110 are provided for protruding beyond the face 1 09a and a spring lock 111, for example of the so-called "mandoline" type, namely which can be displaced axially and turned about 900 against action of a spring 112, is also provided for protruding beyond the face 109a.

Thus, it is possible to place, as shown in Figure 15, various templates 113 which enable marking with a very high precision profiles such as that of a part 114 which is part of a vehicle 3.

A characteristic of the templates 113 consists in that they are made so that they leave a gap 11 5 with the part 114 to be checked, this gap being of course of a known value and controllable itself if required by means of wedges, comparators or other detectors which can be mounted on the template. This disposition allows in particular programming the measuring machine so that its arm 17, its slider 12 or its carrier 7 are displaceable according to a pre-established cycle, and this without the risk of the template 113 coming in engagement with the part to be measured and therefore without the risk of damage to the template.

In addition to the hereabove described template, other parts may be mounted, for instance a scriber point 11 6 whereby a circumference may be marked-off by rotating the head 1 8 and bounding thus a circumference which defines the tolerance limitations inside which a hole may be drilled. It is also possible that the scriber point 11 6 is, as is shown in phantom at 117, made by a marking-off point in alignment with axes of the bores 89 or 90.

As is apparent from the hereabove description, the head 18 may be turned to be brought into any required position by pivoting it about the spindle 58. On the other hand, the core 84 can also turn and be brought in any required position about the spindle 77. Thus, the measuring, marking-off or control tool can be moved to any required point of a semi-spherical surface independently of the movements along the three coordinate axes which the machine authorises, the control of the machine, by means of electrical motors, enabling to easily make a programmable servoing.

The invention is not limited to the embodiments shown and described in detail since modifications may be carried out within its scope as shown in the appendant claims.

Claims (27)

1. A method for controlling various parts, particularly parts of a car body, wherein a set is made of templates corresponding to reference sections of a part to be controlled, and wherein each template is successively assembled to a support head mounted at end of an arm movable along three coordinate axes.

2. A method according to claim 1, where the inclination of the arm as well as that of the template positioned at the end of the arm is adjusted as a function of its weight, so that each template is initially in the same reference position in space.

3. A method according to claim 1, wherein the template is made in the shape of a plate on side of which at least is conformed in a complementary fashion to a section of a part to be checked, and wherein said side is maintained at a constant distance from the theoretical size of the part to be measured.

4. A method according to claim 1, wherein the template is made in the shape of a rotating and marking-off tool bounding a maximum tolerance area relative to a theoretical size.

5. A universal machine for measuring, markingoff and controlling various parts, machine of the type comprising at least a unit having function of a surface-plate for the part and at least one support unit for a head selectively displaceable according the three coordinate axes, characterized in that it comprises for being movable along one of the coordinate axes a fixed length arm supported by a carrier to which said arm is connected via a fulcrum and locking means, said arm having a free end comprising a tool-holder head to which it is connected via a location trim compensation support.

6. A machine according to claim 5, wherein the connection of the arm carrying the head with the carrier movable along one of the cooordinate axes is provided by an intermediate plate to which is fixed said arm, said plate being articulated on a fulcrum provided in the vicinity of one of its ends and having buttonholes for the passage of fixation bolts manually operable, one side of the plate comprising an inclined ramp on which is movable a roller of a carrier controlled in turn by means of a screw, the movement of the carrier being checked by a marking scale.

7. A machine according to claim 5, wherein the support providing the adjustment of the location trim of the measuring head comprises an articulated assembly, locking means and marking members.

8. A machine according to claim 5, wherein the support comprises iron fittings fixed to a flange of the arm end, said iron fittings supporting wings forming, with covers they carry, arcuate grooves in which are placed shoes rigidly connected to the wings of a stirrup for supporting the measuring head.

9. A machine according to claim 8, wherein a bottom part is fixed between the wings of the stirrup, said bottom part supporting square members with arcuate buttonholes in which extend locking screws applying one of the wings of each square member against lugs rigidly connected to the iron fitting fixed to the arm flange.

10. A machine according to one of claims 8 to 9, wherein the shoes are arcuate and displaceable in the groove formed by the wings and the covers they carry by means of an excenter device.

11. A machine according to one of claims 5 to 10, wherein the stirrup supports a marking gauge for its location trim.

12. A machine according to claim 8, wherein the stirrup and the bottom part support, via sockets or pillows, a support and articulation longitudinal spindle for the measuring head.

1 3. A machine according to claim 12, wherein said spindle is constrained between two of the bearings it supports via a clamp nut for destroying plays due to construction.

14. A machine according to claim 12 comprising a slit ring with a clamp screw, said ring being threaded on the spindle and being carried by the stirrup for immobilizing said spindle in any required position previously chosen.

1 5. A machine according to claim 12, wherein the head is connected to the spindle supporting it through a fly-wheel comprising a marking scale and notches cooperating with at least one catch for defining privileged positions of the head relative to the support.

1 6. A machine according to claim 12, wherein the head comprises a tool-holder core rotating about an axis disposed at right angles relative to said spindle.

17. A machine according to claims 1 5 and 16, wherein the tool-holder core is mounted between two pillows to which it is rigidly connected and which are disposed between two fixed plates carried by the rotating fly-wheel, marking scale being provided between at least one pillow and one plate.

18. A machine according to claim 16, wherein the tool-holder core has at least two holes arranged at 450 from one to the other relative to the rotation axis of said core, a mobile dowel being passed by one of said support plates of the core and by one of the holes for forming two privileged marking positions.

19. A machine according to claim 17, wherein the support axis connecting the core with the plate fixed to the rotating fly-wheel of the head is immobilized by means of a slit ring with a clamp screw.

20. A machine according to claim 16, wherein the core is provided at least with two bores, said two bores extending through the core from one side to the other and placed at 900 one relative to the other transversely to the rotation axis of the core.

21. A machine according to claim 20, wherein the core is provided with flat portions at the mouth of the bores formed on it for receiving a bearing plate for a tool-holder.

22. A machine according to claim 20, wherein the tool-holders are fixed by means of an expansion socket and comprise a face in alignment with the axis of the bores receiving the expansion socket, means for centering, fixing and marking the tools being provided from said face.

23. A machine according to claim 5, wherein measuring, controlling and marking-off tools are provided for taking in account manufacturing tolerances.

24. A machine according to claim 23, wherein the tools are constituted by templates.

25. A machine according to claim 24, wherein the templates are kept at a fixed distance relative to the theoretical size of the part to be controlled, detection means for tolerance measurement being further provided.

26. A machine according to claim 5, comprising at least one scriber point mounted as a tool, the scriber point having a marking end provided for being off-set relative to the axis of the reference face of the tool-holder by a measure corresponding to manufacturing tolerance.

27. A measuring machine for the control of various parts sizes, particularly the sizes of a vehicle body being manufactured, comprising on either side of a pit two support bases for two identical assemblies each comprising a horizontal displaceable carrier on one of the bases representing the x axis, a vertical column carried by the carrier and comprising guides representing the z axis and along which is guided a slider representing means for guiding a horizontal carrier representing the y axis and supporting an arm, said arm having a free end comprising a support head for a feeler or detection member, wherein the slider which is vertically movable extends transversely relative to the base and forms a guide of great length for the horizontal carrier movable along the y axis, said carrier carrying an overhanging arm of fixed length at end of which is mounted a support head for the feeler so that deflection of the arm remains constant whatever position of the carrier, the arm having a free end comprising the support head for the feeler member and being mounted oscillating on the horizontal carrier, and means being provided for an angle adjustment of said arm as a function of the deflection it forms in relation with the weight of the head with which it is provided.