Method and apparatus for repairing the chassis and or bodywork of automotive vehicles

A method of repairing a vehicle chassis and/or vehicle bodywork which requires the replacement of a damaged vehicle part with a new vehicle part. The vehicle is clamped to a working bench and the new vehicle part (4), which is to be welded in position for instance, is held firmly in a correct position in relation to the vehicle (1) with the aid of bench-coacting holding devices (5, 18). The bench-coacting holding devices (5, 18) include positionally adjustable means (10, 17) which are intended to coact with specific points of the new vehicle part, the positions of these points in space relative to the vehicle being known. In this regard, the positions in space of the positionally adjustable means are set with the aid of separate measuring equipment. The invention also relates to an arrangement for use when carrying out the method.

The present invention relates to a method and to apparatus for repairing 
the chassis and/or the bodywork of damaged automotive vehicles and then 
particularly for making repairs which require the replacement of damaged 
vehicle parts with new parts. 
When fitting a new part adjacent an undamaged or truly aligned part of a 
vehicle which has been partially demolished as a result of an accident for 
instance, or when replacing rust-damaged parts, the final result is 
totally dependent on the new part being held in precisely the correct 
position in relation to the remainder of the vehicle when fitting said 
part, for instance when welding the part in place. 
Data sheets which define the positions of the different points of the 
chassis and/or the bodywork of car in a space coordinate system are 
available for the majority of makes of private vehicles. The measurement 
points used may have the form of holes, flat surface parts, pins or 
equivalent devices. 
A damaged vehicle is aligned by clamping the vehicle onto a drawing or 
aligning bench. The bench includes measuring equipment which can be moved 
along the bench. The measuring equipment is used initially to measure or 
determine the locations of from three to five undamaged points of the car, 
so as to define the position of the car accurately and precisely in 
relation to the measuring equipment. The car is then aligned, for instance 
by a pulling action, until remaining measuring points on the car coincide 
with corresponding values on the data sheet. 
When welding a new part to a car in replacement for a removed part, it is 
known to clamp the new part in its correct position in space while using 
reference points on the part. The replacement part is held by holding 
devices which can be clamped firmly to the aligning bench and which 
consists in a large number of component parts that can be assembled 
together and the dimensions and angles of which are known. When wishing to 
position, for instance, a pin in a correct position in space for coaction 
with a reference hole on a new car part, there is chosen from a kit of 
fixed component parts those parts which when combined and fitted in a 
chosen position on the aligning bench will result in an external pin being 
located in the desired position. 
However, if the component parts have not been manufactured with any great 
precision or have been damaged or have become worn, the individual 
discrepancies of each separate component part are likely to add together 
so that the final position of the external pin will be totally wrong. 
It is also difficult to carry out quality checks, since such checks require 
the inspection of each separate detail of the entire fixture set-up. 
Adjustable holders provided with scales or holes have also been used 
earlier, although such devices give the same uncertain results as those 
described above. 
The main object of the present invention is to provide a method of the kind 
defined in the introduction which can be applied readily and which 
eliminates the aforesaid drawbacks and which will also produce a result of 
high quality which is not impaired with time. 
The invention is based on the realization that this object can be achieved 
when instead of a large number of fixed components, there is used a few 
components which can be adjusted in different respects and therewith 
adjust the position of the final element which coacts with, e.g., a new 
chassis part with the aid of separate measuring equipment of the same kind 
as that used when aligning the chassis of a car. 
Thus, the present invention provides a method of repairing a vehicle 
chassis and/or vehicle bodywork in which damaged parts are replaced with 
new parts, wherein the vehicle is clamped securely to a working bench and 
a new vehicle part to be fitted, for instance to be welded, is held firmly 
in a correct position relative to the vehicle with the aid of bench 
coacting holding devices which can be locked in relation to the bench and 
which include positionally adjustable means for coaction with specific 
points on the new vehicle part, the positions of these points in space 
relative to the vehicle being known. The inventive method is characterized 
by using separate measuring equipment when adjusting the positions of said 
positionally adjustable means in space. 
The inventive method thus enables a new vehicle part to be positioned with 
absolute precision in space irrespective of any damage to or wear on the 
holding devices used, as the position of the new vehicle part is 
determined with the aid of the measuring equipment and not in dependence 
on dimensions, positions and angles of apparatus components. The method of 
procedure can be repeated any number of times with the same setting 
precision, since the measuring system can be checked in accordance with 
prescribed quality standards and adjusted when necessary. 
Other characteristic features of the inventive method and the 
characteristic features of an arrangement for use when carrying out the 
method will be apparent from the following claims.

One embodiment of such a holding device 5 is shown in FIG. 2, from which it 
will be seen that the device includes a tubular stanchion 6 which is 
mounted in a foot plate 7 such as to enable the stanchion to be adjusted 
between different lateral positions, said foot plate 7, in turn, being 
movable along the bench 3, as evident from FIG. 3 for instance. The 
stanchion 6 receives a threaded spindle 8 which coacts with a nut 20 on 
the stanchion. The nut 20 is suitably of the kind which will enable quick 
adjustments to be made by virtue of an axial movement with no thread 
engagement, and which will also enable fine adjustments to be made by 
virtue of engagement between the spindle threads and corresponding thread 
on the nut 20. The spindle 8 carries a head 9 which functions to clamp a 
selected positionally adjustable device. In the case of the FIG. 2 
embodiment, this device has the form of a vehicle-part supporting rod or 
bar 10 which can be moved in the direction of its longitudinal axis and 
which includes an outer hole 11 intended for coaction with an accurately 
determined reference point, such as a pin or peg which serves as a 
reference point for the new part of the car chassis. 
Before supporting the new vehicle part on the rod 10, it is necessary to 
first bring the hole 11 into a precise and correct position. As 
illustrated in FIG. 3, this is effected in accordance with the invention 
with the aid of known measuring equipment used when aligning the car 
chassis and comprising a slide 13 which can be moved along rails 12. The 
slide 13 carries a multi-part pivotal measuring arm 14 which is provided, 
among other things, with sensing means which sense the angular positions 
of rotation of the different pivot axles, so as to enable the exact 
position of a measuring probe 15 in a space coordinate system to be 
determined. In the illustrated case, the probe is in the form of a cone. 
The measuring equipment also includes an electronic display unit 16 on 
which the precise position of the measuring probe 15 in space is 
presented, among other things. Measuring equipment of this kind is 
marketed under the name Car-O-Tronic by Car-O-Liner AB, Kungsor, Sweden, 
and will not therefore be described in more detail here. However, the 
invention can also be applied with the aid of other measuring systems 
which enable the position of, e.g., the hole 11 in the rod or bar 10 to be 
determined exactly, such that this position can be set in agreement with 
the desired position of that reference point on the new chassis part with 
which said hole shall coact. 
FIGS. 4 and 5 illustrate in more detail how the cone 15 on the measuring 
arm 14 coacts with the hole 11 when adjusting the rod or bar 10 precisely 
to the desired position. Subsequent to this adjustment, the bar 10 is 
intended to support the new chassis part, e.g. the beam 4, as illustrated 
schematically in FIG. 5 in chain lines. The measuring arm 14 and the cone 
15 are therewith removed, so as to enable a reference pin 19 on the beam 4 
to enter the hole 11 on the bar 10. 
In order to correctly position the new chassis part, such as the beam 4, it 
is necessary for at least the position of one positionally adjustable 
device, such as the rod or bar 10, to be determined in this way for 
coaction with a reference point on the new chassis part. As illustrated in 
FIG. 7, it is often necessary to determine two or more support points on 
the new chassis part and to fix these support points in relation to the 
remaining part of the car 1. In the case of the FIG. 7 embodiment, two 
identical holding devices are used to this end, the only difference being 
that the rod or bar 10 of the additional holding device 18 carries an 
angle iron which is provided with an upstanding pin 17 instead of a hole 
11, this pin being intended to coact with a reference hole in the new 
chassis beam. As will be understood by the person skilled in this art, 
other types of support elements having accurately defined contact surfaces 
for engagement with a chassis reference point may be used. 
The holder devices 5, 18 used in accordance with the invention can be moved 
in the longitudinal direction of the bench 3 and adjusted transversely in 
relation thereto. The threaded spindle 8 also enables the holding devices 
to be adjusted vertically, and the rods or bars 10 can be adjusted in 
their longitudinal direction for exact positioning of their reference 
elements, which in the illustrated embodiments consist in the hole 11 and 
in the pin 17 respectively. 
The present invention enables these reference elements 11, 17 to be 
positioned precisely in space without needing to rely upon scales or on 
the setting positions of the different components included in the holding 
devices. Thus, the accuracy of the settings is not dependent on 
manufacturing tolerances of these components and will not be affected by 
any damage thereto or wear thereon. The same holding devices, including 
only a few components, can also be used with different types of cars. 
The invention also enables the reference points of, e.g., a beam on one 
side of the car to be correctly positioned in relation to corresponding 
points on a beam on the other, undamaged side of the car without using 
data sheets showing desired positions. In this regard, it is only 
necessary to first measure the points on the undamaged side of the vehicle 
with the aid of the measuring equipment to establish the positions of 
those points located symmetrically with the points on the other side of 
the car. Among other things, this can be highly beneficial in the case of 
unusual car models or when repairing cars for which no data sheet is 
available. Moreover, the operator himself is able to determine which of 
the reference points shall be used and how many. 
Although the invention has been described above with reference to a 
preferred embodiment thereof illustrated in the accompanying drawings, it 
will be understood that various modifications can be made within the scope 
of the following claims. For instance, the illustrated holding devices and 
the illustrated measuring equipment can be modified in accordance with 
different requirements as dictated by practical circumstances. The 
measuring equipment may, for instance, include an optical laser system or 
an acoustic system, the measuring points being marked in a way applicable 
to the measuring system applied.