Caster wheel control apparatus

In general, the remote control of a caster wheel assembly on a farm implement such as a crop sprayer of the type including a boom rotatable between a transport position and a field position is a complicated operation. In the transport position, the wheel assembly should be fixed, i.e. non-castering and in the field position the wheel assembly should caster freely. A relatively simple apparatus for effecting caster wheel assembly control includes a frame mounted on the boom, a hydraulic cylinder on the frame, and a linkage connected to the piston rod of the cylinder and releasably connected to an arm on the shaft carrying the wheel assembly, whereby initial extension of the piston rod moves the wheel assembly to a turning position, full piston rod extension causes release and thus free castering of the wheel assembly in the field position, and retraction of the piston rod causes re-engagement of the wheel assembly by the linkage to lock the wheel assembly in the transport position. In the turning position, the wheel is at an acute angle with respect to the longitudinal axis of the boom. With such an arrangement the boom can be moved into the field position by moving the implement a relatively short distance of 100 feet, instead of the 200-300 yards normally required.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an apparatus for controlling a caster wheel on a 
farm implement. 
2. Discussions of the Prior Art 
Farm implements such as crop sprayers include elongated booms pivotally 
connected to a trailer for rotation between a transport position in which 
the booms are aligned with the direction of vehicle travel and a use 
position in which the booms extend outwardly, perpendicular to the 
direction of vehicle travel. On currently available implements, the boom 
movement is controlled by the operator from the tractor seat. Examples of 
such implements are described in Canadian Pat. No. 1,230,866, which issued 
to G.S. Pask on Dec. 29, 1987 and in U.S. Pat. Nos. 3,324,956, which 
issued to W.D. Ritchie on June 13, 1967; 3,700,042, which issued to R.E. 
Patterson et al on Oct. 24, 1972 and 3,701,385, which issued to R.E. 
Patterson et al on Oct. 31, 1972. 
In general, the patented devices are somewhat complicated or do not provide 
a satisfactory solution to the problem of controlling the boom supporting 
wheels from the driver's seat. The problems in this case include the 
controlled locking of the wheels in the transport position, simple 
unlocking of the wheels for free castering movement, and the orienting of 
the wheels to enable quick change between the transport and use or field 
positions. 
The object of the present invention is to provide a solution to the above 
identified problems by providing a relatively simple apparatus for 
controlling a caster wheel or wheel assembly on a farm implement which 
facilitates locking and unlocking of the wheel, and the orienting of the 
wheel to enable quick conversion from one condition to another, i.e. free 
castering to locked and vice versa. 
GENERAL DESCRIPTION OF THE INVENTION 
Accordingly, the present invention relates to an apparatus for controlling 
a caster wheel assembly on a farm implement of the type including a boom 
for rotation between a transport position in which the boom is aligned 
with the direction of implement travel and a field position in which the 
boom is angled or perpendicular to the direction of implement travel, said 
apparatus comprising fluid actuated cylinder means for mounting on the 
boom; piston rod means extending out of said cylinder means; linkage means 
connected to said piston rod means for rotation thereby and releasably 
engageable with said wheel assembly, whereby initial extension of said 
piston rod means rotates said linkage means and consequently said wheel 
assembly to a turning position, further extension of said piston rod means 
causes the release of said wheel assembly permitting free castering 
thereof, and retraction of said piston rod means causes re-engagement of 
said wheel assembly by said linkage means to lock the wheel assembly in 
the transport position.

DESCRIPTION OF PREFERRED EMBODIMENTS 
With reference to FIGS. 1 and 2, the apparatus of the present invention 
which is generally indicated at 1 is shown in use on a crop sprayer 2 of 
the type including a trailer 3 for attachment to a towing vehicle (not 
shown). For such purpose, a tow bar 4 is provided on the front or leading 
end of the trailer 3, which is supported by wheels 5. The trailer carries 
a tank 6, containing liquid to be sprayed through a spray tube defined by 
a central fixed section 7, and arms or wings 8. The fixed section 7 of 
tube is carried by a fixed central boom section 10, and the wings 8 are 
carried by movable boom sections 11. The boom sections 11, which are 
supported by wheels 13, are pivotally connected to the central section 10 
for rotation around vertical axes, permitting movement from the transport 
position (FIGS. 1 and 2) in which the boom sections 11 are perpendicular 
to the central boom section 10, and the use or field position (not shown) 
in which the sections 11 are aligned with the fixed section 10, extending 
transversely outwardly from the trailer 3. In the use position, the boom 
sections 11 are fully extended laterally. The sections 11 are releasably 
locked in the extended, use position by so-called boom draws 14 and 
latches 15. Each boom draw 14 includes a pair of pivotally interconnected 
arms 16 and 17. One arm 16 is pivotally connected to the trailer 3 and the 
other arm 17 is pivotally connected to one boom section 11. In the 
extended, field position of the boom section 11, a connector 18 at the 
junction between the arms 16 and 17 is retained by the latch 15. 
The foregoing is a description of existing hardware. The apparatus 1 of the 
present invention is associated with the wheels 13. As mentioned 
hereinbefore, in the roadway transport position, the wheels 13 should be 
locked in the non-castering position (FIGS. 1 to 3). In the use or field 
position, the wheels 13 should be freely castering to increase mobility 
and to prevent crop damage by the wheels. 
The apparatus 1 includes a frame defined by a pair of brackets 20 and 21 
mounted on the boom section 11. Each bracket 20 and 21 is defined by top 
and bottom plates 23 and 24, respectively interconnected by bolts 26 and 
nuts 27. A pair of rods 28 extend between the top plates 23 for 
maintaining the brackets 21 and 22 in spaced apart relationship. One end 
of each rod 28 is welded to a transversely extending, reinforcing strip 30 
on the top plate 23 of the bracket 21, and the other end 32 of the rod 28 
is threaded for receiving nuts 33. The threaded end 32 of the rod 28 
extends through a sleeve 34 on a reinforcing strip 36 on the plate 23 of 
the bracket 20, and is retained therein by the nuts 33. Thus, when the 
nuts 27 clamping the brackets 20 or 21 on the boom section 11 are 
loosened, the nuts 33 can be rotated to change the spacing between the 
brackets 20 and 21. 
One end of a hydraulic cylinder 38 is pivotally connected to an inverted 
L-shaped arm 39 on the top plate 23 of the bracket 20 by a clevis 40 and a 
pin 42. A triangular gusset 43 extends between the arm 39 and the plate 23 
for reinforcing the connection therebetween. A piston rod 45 extends out 
of the other end of the cylinder 38, and is pivotally connected to one end 
of an arcuate lever 46 by a clevis 48 and a pin 49. The other end of the 
lever 46 is connected to the top end of a rod 50 (FIGS. 4 and 5), which is 
rotatably mounted in a sleeve 52 mounted in one edge of the top and bottom 
plates 23 and 24, respectively of the bracket 21. Extension or retraction 
of the piston rod 45 causes a corresponding rotation of the rod 50 in the 
sleeve 52. One end of a second lever defined by a bellcrank 53 is 
connected to the bottom end of the rod 50 for rotation therewith. A lug 55 
(FIG. 5) extends downwardly from the free end of the bellcrank 53 for 
engaging one end of an arm 56, which includes a notch 57 in the outer free 
end thereof. 
The arm 56 forms part of an assembly for supporting the boom wheel 13. 
Actually the arm 56 is connected to the inner end of a shaft 58, which is 
connected to the suspension generally indicated at 59 for the wheel 13. 
The suspension 59 does not form part of the apparatus of the present 
invention and accordingly, is not described in detail herein. The shaft 58 
is generally L-shaped, and the inner vertical end thereof is rotatably 
mounted in a second sleeve 61 which is connected to the top and bottom 
plates 23 and 24 of the bracket 21. For such purpose, the top end of the 
shaft 58 is threaded for receiving nuts 64. The apparatus is completed by 
a locking bar defined by a strip 66 of metal with holes 67 near the end 
thereof for locking the apparatus in the transport condition. 
In operation, with the bar 66 in position (FIG. 3) on the pins 42 and 49, 
the piston rod 45 cannot be extended and accordingly the bellcrank 53 and 
the lug 55 in the notch 57 lock the wheel assembly in the transport 
position. Thus, even if the hydraulic lines (not shown) to the cylinder 38 
were to break, no problems will arise. For transport from one field to the 
next, the safety lock defined by the bar 66 is not required, and the 
apparatus can be operated from the tractor seat. 
When the bar 66 is removed, and the cylinder 38 actuated to extend the 
piston rod 45, the lever 46 and consequently the rod 50 and the bellcrank 
53 are rotated. Thus, the arm 56 is also caused to rotate approximately 45 
degrees (or more) from the transport position (FIG. 3) to the partially 
turned position (FIGS. 4 and 6). Thus, the wheels 13 are angled with 
respect to the boom section 11, and held firmly in such position by the 
cylinder 38 and the interconnecting linkage. By moving the implement 
backwards, the boom sections 11 spread to the use or field position. When 
in the field position, control over the wheel 13 is neither required nor 
desirable. The wheel 13 must be free to caster in order to prevent damage 
to the field. When the piston rod 45 is fully extended (FIG. 5), lug 55 
leaves the notch 57, and the wheel 13 can caster or rotate through 360 
degrees. 
Normally, during spraying, the boom sections 11 are releasably latched in 
the extended position By moving the vehicle in ,reverse, the wheels 13 
become properly oriented, i.e. angled for locking in the transport 
position. Operation of the cylinder 38 causes retraction of the piston rod 
45, and consequently reverse rotation of the lever 46, the rod 50 and the 
bellcrank 53 to move the lug into the notch 57. Continued retraction of 
the piston rod 45 moves the wheel 13 into transport position parallel to 
the boom section 11. With the boom sections 11 released, forward movement 
of the vehicle will cause the boom section 11 to assume the transport 
position. 
For the sake of simplicity, the expression "boom section" has been replaced 
with the term "boom" in the appended claims.