Pulling clamp

A pulling clamp which can engage an automotive frame member at two points. The pulling clamp includes two elongated bow shaped members (12, 14) each of which is provided with at least one elongated slot (18) for the reception of a bolt (66) which is passed through suitable apertures in the frame member (56) to be pulled the bolt being held in place by a nut (68). The bow shaped members are spread apart by a threaded spreading member (34) to firmly clamp opposed side walls of the frame member between the head of the bolt, the nut, and the outer surfaces (20) of the pulling clamp. In one embodiment a second elongated slot (90) is provided inwardly of the first elongated slot (28) so that box sections of smaller width may be engaged by passing a bolt through a second set of elongated slots. In another embodiment threaded apertures (30, 42) are disposed inwardly of the elongated slots (28), which threaded apertures may receive additional gripping means (72).

TECHNICAL FIELD 
The present invention relates generally to a device for straightening 
automobile frames, and more particularly to pulling clamps which can 
engage various frame members of an automotive body and which, after 
securement thereto, can pull these members back to there original 
specifications. 
BACKGROUND OF THE INVENTION 
It is well known in the prior art that automotive frames and sheet metal 
can be straightened and returned to substantially their original 
specifications by engaging the frame or sheet metal with a clamp and 
pulling the engaged member to restore the damaged part. One such example 
is shown in U.S. Pat. No. 3,744,838 which, in FIGS. 1 through 5 shows a 
first design for engaging sheet metal parts, and in FIGS. 6 and 7 a second 
design for engaging a frame members. A unibody pulling device such as that 
shown in U.S. Pat. No. 3,355,771, is designed to pull one side of the 
rail. Since a unibody rail is typically made up of two or more pieces of 
sheet metal which are formed into a box cross section, these types of 
clamps do not always pull properly. Thus, on a hard hit pull, this style 
of clamp can cause the rail to distort and loose its proper box shape. The 
only proper way to pull a unibody rail, which is typically made of high 
strength steels, is by pulling on both sides of the damaged rail. Also, if 
you pull a unibody car rail at one point only with a force of over 2,500 
pounds, it is possible to break the sheet metal off at the clamp contact 
point. This will obviously result in more repair time. However, if the 
rail is secured at two points the frame technician has an option of using 
more power, up to perhaps 3,500 pounds, if needed. 
When pulling on rails, such as skit rails or upper frame rails, which may 
not be box shaped, in the past it has been standard proctice to engage 
these members at one point only. By engaging such members at two 
longitudinally spaced apart points, additional pulling force can be 
exerted on the member, and furthermore, a double angle pull can be 
utilized. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is a principal object of the present invention to provide a pulling 
clamp which may be secured to two points of an automobile frame in order 
to properly pull the frame. 
More specifically, it is an object of the present invention to provide a 
rail pulling clamp which can be inserted into a box frame rail and secured 
thereto at two laterally spaced apart points so that proper pulling forces 
may be employed. 
It is a further object of the present invention to provide a rail pulling 
clamp which may be inserted into box frame rails of varying diameters and 
properly secured thereto to laterally spaced apart locations. 
It is an additional object of the present invention to provide a rail 
pulling clamp which may be secured to rails at longitudinally spaced apart 
points. 
Thus, a rail pulling clamp is designed having two elongated bow shaped 
members which can be inserted into a box shaped rail and secured thereto 
at laterally spaced apart locations, a bolt being inserted into holes 
drilled in the frame member, the bolt also passing through elongated bolt 
receiving slots in the bow shaped members. 
In one modification of the present invention, it is also possible to mount 
gripping means on the exterior surfaces of the bow shaped members to 
engage a rail between the gripping means and the bow shaped members which 
are inserted into the box rail. 
A single bow shaped member may also be utilized when pulling on frame 
sections which are not of a box shape cross section by bolting the box 
shaped member to one location of the rail and then engaging another 
portion with the gripping means to provide the desired two point holding 
system.

DETAILED DESCRIPTION 
In General 
Two slightly differing forms of pulling clamps are illustrated in the 
various Figures., the first form being illustrated in FIGS. 1 through 3 
and the second form being illustrated in FIGS. 4 through 6. The first form 
is designed for pulling frame members of relatively small cross sectional 
box constructions, or alternatively skirt rails and upper frame rails 
which do not have box shaped cross sections. The form illustrated in FIGS. 
4 through 6 is designed primarily for pulling box cross section frame 
members which have intermediate to large cross sections. 
First Embodiment 
The first form of rail pulling clamp is illustrated in FIGS. 1 through 3 
and is indicated generally at 10. It includes first and second elongated 
bow shaped members 12 and 14, respectively. Each bow shaped member has 
spaced apart inner and outer ends 16 and 18, respectively and convex and 
concave sides 20 and 22, respectively. In form illustrated in FIGS. 1 
through 3 the bow shaped members are formed of mildly hardened bar stock 
material which is bent to the illustrated configuration. Pivot receiving 
means are secured adjacent the inner end of each of the bow shaped members 
12 and 14, the pivot receiving means being in the form of thick washers 
24, which are preferably welded to the ends 16. In addition, bracing 
members 26 are suitably welded to the associated pivot receiving means 24 
and the convex surface 20. 
Each of the bow shaped members is further provided with an elongated bolt 
receiving slot 28 adjacent the outer end 18, which slot extends from one 
side 20 to the other side 22. The first bow shaped member 12 is further 
provided with first and second threaded apertures 30, 32, the first 
threaded aperture 30 being more closely disposed to the elongated slot 28 
than the second threaded aperture 32. Mounted within the second threaded 
aperture is a threaded spreading member 34 having a head 36 provided with 
suitable flats which can be engaged by a wrench or the like. The other end 
of the threaded spreading member is provided with a foot 38 which is 
secured thereto by a conventional ball joint construction 40. 
The second elongated bow shaped member 14 is also provided with a first 
threaded aperture 42, which when the parts are held together by a suitable 
pivot, will be in alignment with the first threaded aperture 30. The 
second member is also provided with first and second bearing surfaces 44, 
46, the first bearing surface being disposed on the convex side between 
the first threaded aperture 42 and the pivot receiving means 24, and the 
second bearing surface 46 being disposed on the concave side 22 between 
the pivot receiving means 24 and the first bearing surface 44. 
The first and second bow shaped members are held together by pivot means in 
the form of a clevis pin 48 which passes through the apertures in washers 
24 and a clevis 50. The clevis pin is provided with a ball detent 52 at 
one end and a pull ring 54 at the other end, the ball detent and ring 
serving to maintain the clevis pin 48 in its assembled position. When the 
first and second elongated bow shaped members 12 and 14 are assembled 
together by means of the pivot means 48, not on y will the apertures 30, 
42 be in alignment with each other but the elongated slots 28 will also be 
in alignment with each other. 
The clamp described so far can be used as a pulling clamp. Thus, when it is 
desired to pull a rail of rectangular box section, the box section 56 will 
be provided with drilled holes 58, 60, which are in alignment with each 
other. Washers 62, 64 will now be suitably welded to the exterior surface 
of the frame section 56 with the holes in the washers 62 and 64 in 
alignment with the holes 58, 60. The threaded spreading member 34 is now 
turned in such a manner that the ends 18 of the bow shaped members of 12 
and 14 can be brought closely together, and the pulling clamp will then be 
inserted into the frame rail 56 in such a manner that the slots are in 
alignment with the holes 58 and 60. A bolt 66 will now be passed through 
the holes 58 and 60 and slots 28 to secure the various part together, the 
bolt 66 being secured in place by nut 68. The threaded spreading member 34 
will now be turned in the opposite direction to cause foot 38 to bear 
against bearing surface 46 to spread the ends 18 of the first and second 
members away from each other until they firmly engage the inside walls of 
the box frame member 56. A hook 70 or the like will now be passed through 
the clevis 50 and a suitable pulling force can be applied to the rail 56 
to bring it back to its desired position. 
By securing the pulling clamp 10 at two points the frame technician can use 
more power than if the pulling clamp were only secured at one point. In 
addition, good control is achieved by pulling at two points as a common 
force is applied to both sides of the box section, which will keep the 
sides of the box section from buckling during pulling. 
In some situations it may be desirable to apply additional clamping force 
to the end of the frame member, particularly when applying a compound 
angle pulling force. To this end gripping means, which are indicated 
generally at 72, may be mounted on either one of the bow shaped members 12 
or 14 or both as illustrated in FIG. 3. The gripping means, are mounted on 
the convex surface of the bow shaped members. Each of the gripping means 
includes an elongated bar-shaped gripping member 74, the gripping member 
74 being provided with a separate bearing surface 76 at one end, and first 
and second threaded apertures 78, 80. The bearing surface is disposed on 
that side of the bar-shaped member which is adjacent the convex surface 
20. The bearing surface can cooperate with a suitable corresponding 
separate surface 82 on the associated elongated bow shaped member 12 or 
14, which surface 82 is disposed between the elongated slot 28 and the 
first threaded aperture 30. The gripping means further includes a bolt 84 
which passes through the first aperture 78 in the gripping member 74, the 
bolt also passing through the first aperture 30 on the associated bow 
shaped member 12 or 14 to mount the gripping means 72 on the convex 
surface of the bow shaped member. The gripping means further includes a 
second bolt 86 which is screwed in to the second threaded aperture 80 in 
member 74, the bolt 86 being provided with a rounded end 88 which is 
adapted to bear against the bearing surface 44. 
When the pulling clamp is utilized in the manner indicated in FIG. 3, after 
the spreading member 34 has spread the bow shaped members apart as 
indicated the gripping means are mounted on to the bow shaped members. 
Bolt 84 will initially tighten down to bring the bearing surface 76 into 
contact with a portion of the rail, and then bolt 86 will be tightened 
further to ensure proper firm engagement. 
While not illustrated, it should be appreciated that if a piece of sheet 
metal were to be pulled, or if a frame section, which is not of a box 
cross section, were to be pulled that one half of one of the clamps 
illustrated in FIGS. 1 through 3 could be utilized. Thus, the two bow 
shaped members 12 and 14 could be disassembled from each other, and the 
clevis pin 48 could then be reinserted only through one of the washers 24 
to secure a clevis to one of the members 12 or 14. Again, a suitable hole 
will be drilled through the metal to be pulled, re-enforced by a suitable 
washer which is welded about the hole, and bolted in place with a bolt. 
The clamp 72 will also be utilized to further secure a single bow shaped 
member to the material to be pulled to provide a secure two point holding 
system. 
It can be seen from an inspection from FIGS. 1 through 3 that the bow 
shaped sections 12 and 14 have a substantial straight section which 
extends from the ends 18 all the way back to the bearing surface 44 and 
even a little bit beyond that point. 
Second Embodiment 
The second form of rail pulling clamp is illustrated in FIGS. 4 through 6 
and is indicated generally at 11. It is in many respect very similar to 
that shown in FIGS. 1 through 3, with the principal exception that the 
second embodiment, is designed for pulling box frames of a greater variety 
of widths, and it is not provided with means to which the second gripping 
means 72 may be secured. Thus, in this design, the first threaded aperture 
30 or 42 is replaced with an elongated bolt receiving slot 90, 92. When 
pulling a box cross section frame member 94 of intermediate width, after 
suitable holes have been drilled in the frame member and washers 62 and 64 
secured thereto, the pulling clamp of this design is inserted into the 
frame member and a bolt 66 will be passed through the elongated slots 90 
and 92, the bolt being secured in place by nut 68. The parts are then 
spread by engaging the head 36 of the threaded spreading member 34 and 
causing it to bear against suitable bearing surface on the other of the 
elongated bow shaped members. Once the parts have been suitably spread, it 
is then only necessary to engage the clevis 50 with a suitable pulling 
hook 70 in order to properly pull the parts. 
When engaging a rail which has a large width box section the bolt 66 is in 
turn passed through the slots 28 which are closest to the ends 18 of the 
spreading members. 
As shown in FIGS. 4 through 6, the pivot receiving means need not be 
separate washers which are welded on to the ends of the bow shaped members 
but can be merely apertures formed in the ends, the ends having been bent 
and reshaped to the desired position. Thus, the bow shaped members 12 and 
14 of the pulling clamp 11 could be individual forged pieces. In addition, 
the threaded spreading member can be merely provided with rounded end 
portion 98 which can bear against a suitable bearing surface 47. 
While two different forms of the present invention have been disclosed, it 
should be noted that other forms of apparatus may be employed for 
differing situations. Therefore, while preferred embodiments of the 
present invention have been shown and described above, it is to be 
understood that this invention is not to be limited to the particular 
details shown and described above, but that, in fact, widely differing 
means may be employed in the broader aspects of this invention.