C-frame assembly for bulldozer

In an angled bulldozer blade and tractor assembly, a C-frame is constructed in two parts with interfitting elements at the midportion of the C-frame which are held together by axially aligned bearings or sleeves. A blade pivoting pin extends through the midportion of the interfitting elements with the axis of the pin lying transverse to the axis of the aligned bearings or sleeves. Parts of the interfitting elements of the connection are shaped to permit relative rotation between the two halves of the C-frame, particularly for use during storage and shipment of the C-frame.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
In an angled bulldozer blade and tractor combination having a C-frame and, 
in particular, an improved connection between the two halves of the 
C-frame. 
2. Description of the Prior Art 
At one time, and for certain applications even today, C-frames are 
constructed substantially of one piece. This has resulted in problems in 
shipment of the C-frame and in manufacturing the C-frame in such a way 
that the trunnion mountings at each end of the arms of the C-frame are in 
a common plane for attachment to the tractor. An improvement was adopted 
sometime ago wherein the C-frame was broken just to the right or to the 
left of the midportion of the C-frame and flanges were fixed on the 
opposite ends of the two halves of the C-frame which could then be bolted 
together for use or unbolted for storage and shipment. This had a 
disadvantage in that the holes in the respective flanges had to be 
carefully aligned with the reference points for the trunnion mountings at 
the ends of the arms to be sure that the C-frame, when assembled, could be 
assembled to the tractor. The C-frame with the flanged and bolted halves 
must be taken apart for shipment and reassembled in the field. The bolted 
joint causes manufacturing problems in that the holes for the joint must 
be aligned in both halves so that when they are bolted together the 
dimension across the ends of the arms of the C-frame is fixed and must 
match the tractor. In order to ensure a good joint, all of the bolts must 
be kept tight and where the bolts are put in in the field, it is almost 
impossible to ensure proper installation torques. Also, since the C-frame 
is, in effect, one piece after being bolted together, the sharing of side 
loads from left to right or from right to left is not positive. 
In an attempt to provide a means for positively aligning the two halves of 
the C-frame, structure has been proposed whereby tapered shear sleeves are 
bridged across the juncture between the two halves prior to bolting the 
two halves together which, presumably, better aligns the two halves and 
provides a stronger sheer plane between the two halves. This is relatively 
expensive, requires very accurate machining and still does not assure that 
the spacing between the halves will be accurate or that the planes of the 
two halves will coincide with the mounting. 
A pivot mounting between the two halves has been proposed whereby the pin 
for mounting the blade to the C-frames is connected directly to the spacer 
between the two halves and surrounding the pivot pin. This device has the 
disadvantage that for shipment, the pin is removed and must be stored 
separately which always raises the possible problem of losing the pin. 
Secondly, this construction provides for the blade lift connection being 
an integral part of the joint between the two halves of the C-frame. This 
reduces the flexibility of the connection between the two halves of the 
C-frame, and requires added space between the tractor and the C-frame for 
the connection for the lift arrangement. In addition, the trunnion 
mounting for the lift assembly is a loose item which must be disassembled 
and stored separately when the two halves of the trunnions are separated. 
Also, with the trunnion mounted between the two halves at the pivot 
connection of the C-frame, the two halves of the C-frame cannot be easily 
adjusted to fit the mounting on the track roller frame. 
SUMMARY OF THE INVENTION 
The present invention is directed to overcoming one or more of the problems 
as set forth above. 
According to the present invention, the C-frame is divided into two halves 
with interfitting segments or elements at the common terminal ends 
thereof. Pivot pins or sleeves interfit between the interfitting segments 
or elements of the halves and are affixed thereto so that the two halves 
of the C-frame can be pivoted about a common axis. Bearing surfaces for a 
pivot pin for mounting the blade to the C-frame extend transverse to the 
axes of the sleeves and cross the common axis of the sleeves at right 
angles thereto. Separate trunnion mounts are provided on each half of the 
C-frame for connection to lift cylinders for raising and lowering the 
blade. 
The two halves being pivotally affixed together, have no pins to lose 
during shipment or storage. By using separate trunnions for mounting the 
ends of the lift cylinders, there are no removable trunnion mounts at the 
juncture of the two halves, which, likewise, can be lost during shipment 
or storage. Since the two halves are pivotally connected together, it is 
not necessary to maintain an exact spacing between the free ends of the 
two halves for mounting the free ends on the tractor, since the distance 
between the free ends can be varied about the common axis of the sleeves. 
The pivoting of the two halves in the manner specified ensures equal side 
loading on each half of the C-frame, which overcomes many of the problems 
inherent in the prior art constructions.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring broadly to FIGS. 1 and 2, a tractor 10 has a drive sprocket 11 
and an idler wheel 12 about which is drivingly mounted a continuous track 
13. A C-frame 15 is comprised of two side arms or halves 16 and 18 with 
the rear end portions 17,19, respectively, of the side arms being 
pivotally connected through trunnion sockets and retainers 20 to a 
trunnion carried by a track roller frame 21. The C-frame 15 is connected 
to the exterior of the track roller frame 21 and has the midportion 22 of 
the C-frame 15 pivotally connected to the lower midportion of the rear of 
the bulldozer blade 24. 
Thrust members 26 and 28 are connected to the lower rear corner portions of 
the blade 24 and have brackets 30 that are pivotally connected to 
appropriate socket members 32 carried on the upper surfaces of the two 
halves or arms 16,18 of the C-frame. Three socket members 32 are provided 
on the top surface of each half 16,18 of the C-frame 15 in substantially 
equally spaced apart relationship. Each thrust member 26,28 has a tilt 
strut 34 extending from the bracket 30 and being connected to the upper 
rear corner portions of the blade. The thrust members 26,28 and brackets 
30 are used to give the blade 15 the angled position desired and the tilt 
struts 34 are used to give the blade the tilt position desired. 
A pair of trunnion mounts 36 are attached to the top surfaces of the two 
halves or sides 16,18 of the C-frame 15 in equally spaced relationship 
from the middle of the C-frame. A pair of lift cylinders 38 are carried by 
the tractor 10 and have the ends of the rods of the cylinders being 
pivotally connected to the trunnion mounts 36 on the C-frame. The lift 
cylinders 38 are used to raise and lower the front of the C-frame 15 and 
the bulldozer blade 24. 
Referring specifically to FIGS. 3 and 4 and, in particular, as they relate 
to FIG. 2, side half 16 has an enlarged element or section 40 extending 
axially therefrom. The enlarged element or section 40 has a vertically 
disposed stepped bore 42 such that the midportion 44 of the bore has a 
reduced diameter which creates a pair of outwardly and oppositely facing 
shoulders or abutments 46 at the bottom of the enlarged diameter end 
portions 48,50. Along an axis disposed at right angles to the axis of the 
bore 42 is a transverse bore or aperture 52 which tapers 53 at the 
midportion from an enlarged diameter end portion 54 at the front of the 
C-frame to a reduced diameter end portion 55 at the rear of said C-frame. 
The diameter at the midportion of the taper 53 is smaller than the 
diameter of the midportion 44 of the bore 42 and smaller than the axial 
length of said midportion 44 of bore 42. The end portions 54,55 of the 
bore or aperture 52 are slightly enlarged to receive bushings 56 through 
which a pivot pin 58 passes. Pivot pin 58 is tapered in the midportion to 
mate with the tapers 53 in the bore 52. The pivot pin 58 passes through 
the element 40 and is prevented from escaping from element 40 by an 
overhanging washer 62 being held by bolt 60 against the end face of the 
pin 58. When the tapers in pin 58 and bore 52 engage, the washer 62 will 
be spaced from the end face of the element 40 as shown in FIG. 3. The 
inner end of the pin 58 in FIG. 3 is shown broken away but, in fact, it 
extends to and has a pair of outwardly extending, parallel spaced apart 
plates which are adapted to be pivotally connected to a lug on the rear of 
the bulldozer blade. The blade 24 pivots about the longitudinal axis of 
the pin 58 to assume various tilt positions relative to the C-frame. It is 
to be understood that various commercially available universal-type 
connections could be used between the C-frame and the center of the blade 
such as a ball and socket, a ball bushing, a single-ear universal or a 
two-ear universal arrangement would be operative. 
The side arm or half 18 has a bifurcated element 66 including a pair of 
outwardly extending spaced apart legs 68,70 formed integrally with the end 
of the arm 18. The respective legs 68,70 of the element 66 straddle the 
element 40 on side arm or half 16 and have openings 72,74 therein which 
are axially aligned with each other and with the openings 48,50 in the 
element 40. A pair of bearing sleeves 76,78 are inserted through the 
aligned openings 72,48 and 74,50 in the elements 66 and 40 and bottom on 
the abutments or shoulders 46 in the bore 42. The bearing sleeves 76,78 
bridge the opening between the bifurcated legs 72,74 and the element 40. 
Caps or plates 80 are positioned on the opposite sides of the bifurcated 
legs 68,70, which plates or caps are welded to said legs 68,70. The 
sleeves 76,78 do not extend the full distance between shoulders 46 and 
caps 80 and may be press fit into portions 48,50 of bore 42 in element 40 
and may be clearance fit into openings 72,74 in the legs 68,70. With the 
bearing sleeves 76,78 bearing against the shoulders 46 formed in the bore 
42 in the solid element 40 and with the plates or caps 80 welded to the 
outer surface of the legs 68,70 of the bifurcated element 66, it will be 
clear that the bearing sleeves 76,78 are trapped therebetween and serve as 
permanent pivots for the two side arms or halves 16,18 of the C-frame. The 
axis of the pivot pin 58 lies transverse to and crosses the axis of the 
pivot sleeves 76,78 so that the two halves of the C-frame pivot about the 
vertical axis of the sleeves 76,78 and the blade 24 pivots about the 
horizontal axis of the pin 58. The bearing sleeves 76,78 are shown in two 
parts, but it should be understood that a single sleeve could be used 
thereby eliminating the shoulders 46 in the opening 42. If a single sleeve 
is used, a centered clearance hole would be formed therein to permit the 
cross pin 58 to pass through. It is also possible to have the sleeves 
76,78 in the form of a pin which would pass through the legs 68,70 and 
element 40 along an axis offset from the axis of the pin 58. 
Since the openings 72,74 in the bifurcated arms and the bore 42 with 
portions 48 and 50 in the solid element 40 of the C-frame 15 are preformed 
or drilled in the factory, the accuracy of the locations of the openings 
can be rather precisely maintained without complication so that the 
bearing sleeves 76,78 can be inserted and secured in place by the welded 
caps 80 without undue complication or expense. With the two side arms or 
halves 16,18 pivoted relative to each other about the vertical axis of the 
sleeves 76,78, the trunnion bearing ends 17,19 of the two side arms or 
halves 16,18 can be brought together for checking alignment and for 
shipment. With the ends 20 properly aligned, there is no problem in 
opening the ends 17,19 of the halves 16,18 to the proper spacing for 
attachment to the track roller frame 21 of the tractor. 
A C-frame 15 that is to be mounted on a tractor 10 will be unloaded from a 
flatcar, or the like and the trunnion bearing ends 17,19 of the two halves 
like, will be separated by pivoting one relative to the other about the 
axis of the bearing sleeves 76,78. The trunnion bearing ends 17,19 will be 
secured with trunnions carried by the track roller frame 21. The pivot pin 
58, which is either preassembled in the bore 52 in element 40 or will be 
assembled therewith, will be inserted through the bearings in the solid 
element 40 and will be secured in position relative thereto by means of 
the bolt 60 threaded into the end of the pin 58 which will urge the washer 
62 against the side of the solid element 40. The other end of the pivot 
pin 58 will have its bifurcated portion straddle the lug carried by the 
rear of the blade 24 whereupon passing a pin through the bifurcated 
portion and the lug will secure the C-frame 15 to the blade. Lift 
cylinders 38 are connected to the trunnion mounts 36 carried by the top 
surfaces of the two side arms or halves 16,18 of the C-frame 15 so that 
the blade 24 and C-frame 15 can be raised and lowered about the pivot axis 
passing through the trunnions on the trunnion bearing ends 17,19 of the 
arms 16,18 of the C-frame. 
So as to permit the side arms or halves 16 and 18 to pivot relative to each 
other about the axis of the bearing sleeves 76,78, the solid element 40 
has the sides of the enlarged central portion 82 cut or molded away along 
a circular wall 84 centered at the axis of the sleeves 76,78. As viewed in 
FIG. 3, the circle defining the wall 84 has a radius R, which wall 84 
gradually tapers outward at 86 to merge with the side faces of the element 
40. The wall 84 abuts against the enlarged midportion 88 of the element 
40. The other side arm or half 18 of the C-frame 15 has the legs 68,70 of 
the bifurcated element 66 hollowed in the center portion thereof as shown 
in FIG. 4 to provide walls 90 which are curved inward in the midportion as 
viewed in FIG. 3. The walls 90 of the element 66 are spaced from the walls 
84 of element 40 and, due to the circular shape of the walls 84, the 
element 40 can be pivoted relative to the element 66 without the enlarged 
portions 82 of element 40 contacting the adjacent parts of element 66. The 
midportion 88 of the element 40 nests in the spaced area between the legs 
68,70 of the element 66. The cut away sections defined by walls 84 and the 
aligned wall 90 of element 66 are made in such a way as to provide maximum 
strength to the joint and still permit freedom of movement between the 
ends of the two side arms or halves 16,18 of the C-frame 15 so that the 
two side arms or halves 16,18 can be pivoted about the axis of the sleeves 
76,78 to define the smallest possible outer periphery for storage and/or 
shipment.