Remote controlled steering mechanism

A steering mechanism for a remotely-controlled golf caddie having a drive motor coupled to a steering assembly by a non-positive coupling. The non-positive coupling between the drive motor and the steering assembly allows the steering assembly to disengage from the drive motor when the caddie runs into an obstruction. Also, the steering mechanism uses a potentiometer assembly for allowing the caddie to center itself after receiving a command to turn left or right.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to remote controlled golf caddies and, more 
particularly, is directed to a steering mechanism for such remote 
controlled golf caddies. 
2. Description of Related Art 
One method of carrying golf clubs over the fairways of a golf course has 
been through the use of a motorized golf caddie. While there exists a 
variety of types of motorized caddies, including some which the golfer may 
ride on, those motorized golf caddies which are directed by a remote 
control have recently been popular. Such remote controlled golf caddies 
allow the golfer to reap the exercise benefits of walking the golf course 
without having to carry a heavy bag of golf clubs or worry about manually 
directing the caddie. 
Generally, the remote controlled golf caddies of the type described are 
directed by means of radio signals sent by the user of the remote control 
to the caddie. These signals are processed and instruct the caddie to stop 
or move forward, left or right as desired. 
For steering the caddie in a left or right direction, the caddie is 
equipped with a receiver to process the left and right directional signals 
sent by the remote control. These signals are transmitted to a steering 
mechanism which includes a drive motor positively coupled through 
interlocking gears or linkage to a steering assembly having a steering 
wheel. The drive motor, depending on the signal received from the remote 
control, will turn the gears in either a left or right direction. The 
gears will then turn the steering assembly accordingly. 
A major difficulty with the steering mechanisms of the type discussed above 
is that by positively coupling the motor to the steering wheel assembly, 
the steering wheel assembly cannot become disengaged from the motor. Thus, 
when the caddie runs into an obstruction, such as a pothole, a shock is 
sent through the steering assembly and the gear coupling back to the 
motor. Indeed, such a shock may reverse the direction of the motor. This 
can cause great damage to the gears which couple the drive motor and 
steering assembly, as well as to the drive motor itself. Once the gears 
and motor have been damaged, the caddie is useless until repairs can be 
made by a repair shop. These repairs can be very expensive. 
Also, remote controlled steering mechanisms of the type described generally 
will continue to turn in the direction dictated by the user of the remote 
control until another signal is sent which turns the golf caddie back to a 
straight course. For example, at the end of a left turn, the user would 
have to turn the mechanism right until the caddie was brought back to a 
centered position. Sometimes, continual switching between left and right 
is required before the caddie is exactly straightened, causing frustration 
to the golfer operating the remote control. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is therefore a primary object of the present invention to provide a 
steering mechanism for a remote controlled golf caddie which is not easily 
damaged when the golf caddie runs into an obstruction. 
Another object of the present invention is to provide a steering mechanism 
for a remote controlled golf caddie which is easily repaired. 
A still further object of the present invention is to provide a steering 
mechanism for a remote controlled golf caddie in which the direction of 
the golf caddie is easy to control. 
The foregoing and other objects are achieved in accordance with one aspect 
of the present invention through a steering mechanism for a 
remotely-controlled motorized golf caddie comprising a steering wheel 
assembly, a motor for turning the steering wheel assembly and means for 
non-positively coupling the motor to the steering wheel assembly. 
In accordance with another aspect of the present invention, the steering 
wheel assembly comprises a steering wheel and a fender assembly connected 
to the steering wheel. The fender assembly comprises a yoke connected to 
the steering wheel, a plate located at the top of the yoke and above the 
steering wheel, and a fender connected to the plate. The fender comprises 
a substantially stiff material having a first portion extending rearwardly 
and downwardly from the plate and behind the steering wheel, and a second 
portion forming a platform extending laterally from the first portion. The 
platform forms a curved track adapted to be rotated for steering the golf 
caddie. 
In accordance with still another aspect of the present invention, the 
steering mechanism comprises a drive wheel connected to the motor, the 
motor being capable of rotating the drive wheel in either of two 
directions. The means for non-positively coupling the motor to the 
steering wheel assembly comprises the placement of the drive of the drive 
wheel on the platform. 
In accordance with yet another aspect of the present invention, the 
steering mechanism comprises housing means for supporting the motor and 
the steering wheel assembly. Also, the steering mechanism comprises means 
for permitting the drive wheel to slip along or disengage from the 
platform when the steering wheel encounters an obstacle. The means for 
permitting the drive wheel to slip along or disengage from the platform 
comprises a spring having a first end and a second end. The first end of 
the spring is connected to the motor and the second end of the spring is 
connected to the housing means. 
In accordance with yet another aspect of the present invention, there is 
provided a steering mechanism for a remotely controlled golf caddie which 
comprises a steering wheel assembly, housing means for supporting the 
steering wheel assembly, and potentiometer means mounted in the housing 
means for self-centering the steering wheel assembly. The steering 
mechanism further comprises means for coupling the steering wheel assembly 
to the potentiometer means for permitting the potentiometer means to 
detect rotation of the steering wheel assembly. The potentiometer means 
comprises a potentiometer body and a rotatable potentiometer shaft 
extending from the potentiometer body. The rotatable potentiometer shaft 
fits with the coupling means so that the potentiometer shaft turns with 
the steering assembly. 
In accordance with still another aspect of the invention, the means for 
coupling the steering wheel assembly to the potentiometer means comprises 
a bearing shaft having first and second ends and a screw extending through 
the steering assembly and into the first end of the bearing shaft, the 
rotatable potentiometer shaft fitting into the second end of the bearing 
shaft. There are means in the housing means for preventing rotation of the 
potentiometer body when the steering assembly and the potentiometer shaft 
turn. The means for preventing rotation of the potentiometer body 
comprises clip means for removably mounting the potentiometer body in a 
fixed position in the housing. Electronic circuit means return the 
potentiometer shaft to the fixed position of the potentiometer body. 
In accordance with another aspect of the present invention, there is 
provided a steering mechanism comprising a steering assembly, motor means 
for turning the steering assembly in a left or right direction, a housing 
having a forward portion and a rearward portion, and means for 
self-centering the steering assembly. The means for self-centering the 
steering assembly are located in the forward portion of the housing, and 
the motor means for turning the steering assembly are located in the 
rearward portion of the housing.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring now to the drawings, there is illustrated in FIG. 1 a perspective 
view of a remote controlled motorized golf caddie constructed in 
accordance with a preferred embodiment of the present invention. 
As shown in FIG. 1, the remote controlled golf caddie comprises a 
substantially long and narrow frame 10 and a rear axis 12 perpendicularly 
connected to the rear of frame 10. On each end of rear axis 12 are rear 
wheels 14 and 15 which drive the caddie forwards. Extending upward from 
rear axis 12 and angling away therefrom is a handle 16 for pushing the 
golf caddie when it is not powered by a motor. Connected to the rearward 
portion of frame 10 and just below the handle 16 is a battery holder 18 
comprising a tray-like structure. Placed in the battery holder 18 is a 
battery 20. Rearward of battery holder 18 on axis 12, and next to the 
handle 16, is a radio receiver 22 for receiving signals sent by a remote 
control. 
Extending forwardly of frame 10 is a steering housing 25. Steering housing 
25 extends outward and upward from frame 10. Located below the forward 
portion of steering housing 25 is a front wheel assembly 28. Attached to 
the rearward portion of steering housing 25 is a bag holder 26 in which 
the lower portion of a golf club bag is placed. 
Referring now to FIG. 2, there is illustrated a cross-sectional view 
through steering housing 25. It is seen to house a motor assembly 52 
located rearwardly of front wheel assembly 28 and potentiometer assembly 
24 located above steering wheel assembly 28, all of which are to be 
described in greater detail hereafter. 
Steering wheel assembly 28 comprises a steering wheel 48 connected to a 
fender assembly 30, the latter being shown in more detail in FIGS. 3 and 
4. Fender assembly 30 comprises a yoke 34 which straddles both sides of 
front wheel 48 and is attached through the center thereof. Located at the 
top of yoke 34 is a substantially flat plate 32 which is curved at its 
front end. Plate 32 and yoke 34 actually form one piece. Plate 32 contains 
a hole 44 through which a screw is inserted for attaching fender assembly 
30 to the potentiometer assembly 24, as will be described in greater 
detail below. 
Welded to the rear portion of plate 32 and extending rearwardly and 
downwardly from yoke 34 is a fender 36 made from a substantially stiff 
material such as stainless steel. The bottom part of fender 36 forms a 
platform 38 which extends laterally from a rear portion 37 of fender 36. 
Thus, rear portion 37 and platform 38 form an L-configuration. Rear 
portion 37 also contains stiffening ribs 42 which appear as indentations 
in fender 36 as shown in FIG. 4. A small tab 39 extends upwardly from each 
end of platform 38. Situated on platform 38 is an arcuate track 46. 
Referring now to FIG. 5, motor assembly 52 comprises a motor 54 connected 
to a gear box 56 located in front of motor 54. Attached to the front of 
gear box 56 is a motor mount 58 through the front of which extends a 
turning shaft 64. Located below motor assembly 52 and extending from motor 
mount 58 downwardly and rearwardly is a spring 60 which is connected to 
motor mount 58 by means of a rivet 62. As seen in FIG. 2, the other end of 
spring 60 is connected to a mounting box 50 located forwardly of frame 10. 
The top of mounting box 50 is attached directly to housing 25 as at 51. 
Still referring to FIG. 2, attached to the end of turning shaft 64 is a 
drive wheel 66 which is preferably made of rubber. When assembled, drive 
wheel 66 sits on platform 38 of fender 36. The amount of force created by 
drive wheel 66 against platform 38 is determined by spring 60 used to 
mount motor assembly 52 to mounting box 50. By placing drive wheel 66 on 
platform 38, motor assembly 52 is coupled to steering assembly 28. Also, 
since drive wheel 66 is merely placed on platform 38, drive wheel 66 may 
easily slip along or become disengaged from platform 38 when, for example, 
the caddie engages an obstacle such as a pothole, curb or tree. Such a 
coupling is referred to in this application as a "non-positive" coupling. 
The ease with which drive wheel 66 will disengage from platform 38 depends 
in part on the amount of force created by spring 60 in forcing drive wheel 
66 against platform 38. 
Located above steering wheel assembly 28 is potentiometer assembly 24. 
Referring to FIG. 6, potentiometer assembly 24 comprises a potentiometer 
83 having a potentiometer body 84 which has a rotatable shaft 86 extending 
downwardly therefrom. Potentiometer body 84 is fixed in place by means of 
a clip 90 which engages opposed, U-shaped walls 92 formed in housing 25. 
As shown in FIG. 7, clip 90 contains arms 94 which fit around walls 92. 
There is a hole 98 in clip 90 through which rotatable potentiometer shaft 
86 extends. Clip 90 is further held in place by means of a lock nut 88. 
Rotatable potentiometer shaft 86 is removably fitted in the top of a 
rotatable bearing shaft 82 which is surrounded by ball bearings 94. 
Rotatable potentiometer shaft 86 is secured to rotatable bearing shaft 82 
by a set screw 87. A screw 80 extends through plate 32 of steering 
assembly 28 and screws into the bottom of rotatable bearing shaft 82. 
Thus, potentiometer 83 is connected to steering assembly 28. Moreover, as 
steering assembly 28 turns, so will rotatable bearing shaft 82 and 
rotatable potentiometer shaft 86 fitted therein. Potentiometer assembly 24 
is secured to housing 25 by means of screws 96. 
Referring back to FIG. 2, the steering mechanism of the present invention 
operates in response to electronic signals, described in more detail 
below, which control motor assembly 52. In accordance with such electronic 
signals, drive wheel 66 is turned in a left or right direction along track 
46 of platform 38. Tabs 39 on platform 38 limit the movement of drive 
wheel 66 by intercepting motor mount 58. When drive wheel 66 is turned in 
a left or right direction, fender 36 is turned by means of the friction 
created by drive wheel 66 against platform 38. The movement of fender 36 
causes plate 32 and yoke 34 to move in the same direction, which then 
causes front wheel 48 to turn in the desired direction. 
Since steering wheel assembly 28 is connected to potentiometer assembly 24, 
rotatable bearing shaft 82 will turn as wheel assembly 28 turns. This 
causes potentiometer shaft 86 to turn as well. Once potentiometer shaft 86 
becomes out of line with the fixed position of potentiometer body 84, 
electronic signals, described in more detail below, turn wheel assembly 28 
to a centered position. 
Referring now to FIG. 8, there is shown a block diagram of the electronic 
circuitry which processes the signals relayed by the remote control. A 
signal from the remote control is received by a receiver 22 placed on the 
golf caddie. The signal is then sent to a decoder 104 which determines 
whether the signal means the golf caddie should stop, start, turn left or 
turn right. If the signal is for the golf caddie to start or stop, the 
signal is sent via line 105 to drive logic 106 which instructs a main 
drive motor for the caddie 107 to turn rear wheels 14 and 15, or to stop 
turning wheels 14 and 15, depending on the command. 
Should receiver 22 receive a signal that the caddie should turn left or 
right, the signal is sent from decoder 104 to steering logic 108. Steering 
logic 108 then forwards the turn signal to a steering motor command 110 
which instructs motor assembly 52 to turn drive wheel 66 in the correct 
direction. This will, in turn, cause steering assembly 28 to turn 
accordingly. Should a signal to turn the caddie right be received, for 
example, steering logic 108 will forward an appropriate electronic signal 
to steering motor command 110 which will instruct motor assembly 52 to 
turn drive wheel 66 to the right along track 46 until it can go no 
further. As long as the caddie continues to receive a turn right signal, 
drive wheel 66 will remain at its farthest possible position to the right 
on track 46, and motor assembly 52 will be instructed to shut off. 
Once the signal to turn right ceases (i.e., stops being applied by the user 
of the remote control), an error signal will be sent by potentiometer 83 
over line 85 back to steering logic 108 that essentially says that 
steering assembly 28 is no longer centered. In other words, potentiometer 
83 tracks the turning of steering assembly 28 and compares the position of 
steering assembly 28 to the centered or "null" position. After receiving 
the error signal from potentiometer 83, steering logic 108 sends a signal 
to steering motor command 110 that motor assembly 52 should turn drive 
wheel 66 back in the other direction until the caddie is centered. Once 
centered, motor assembly 52 will shut off until such time that another 
directional signal is received. 
The circuitry may also contain a steering limit timer 112. Steering limit 
timer 112 is included so that if a command is received which cannot be 
satisfied, motor assembly 52 is shut off. For example, if drive wheel 66 
has disengaged from platform 38, motor assembly 52 would shut off. This 
would occur after a pre-determined time, preferably consisting of a few 
seconds. 
The circuitry may also contain a steering trim adjustment 116. Steering 
trim adjustment 116 is essentially an electronic potentiometer paralleling 
the mechanical potentiometer 83 described herein so that whatever 
linearity errors exist in whatever part of the circuit, it is trimmed up 
so that the wheel goes in a straight line in the absence of a signal. A 
second mechanical potentiometer could also be used here, however, it was 
determined that performing this function electronically was easier. 
As previously discussed, in the preferred embodiment the motor assembly 52 
is mounted to the caddie by means of a spring 60. Should the caddie 
encounter a particularly rough surface, or an obstruction such as a 
pothole, spring 60 will, by means of motor assembly 52, cause drive wheel 
66 to disengage from platform 38, usually by slipping on track 46. Drive 
wheel 66 will disengage from platform 38 because of the non-positive 
coupling between steering assembly 28 and motor assembly 52. Once drive 
wheel 66 has disengaged from its position on platform 38, potentiometer 83 
will cause motor 50 to turn drive wheel 66 to a position which will center 
steering assembly 28. 
The advantage of the non-positive coupling which allows drive wheel 66 to 
disengage from platform 38 is that little or no damage is caused to motor 
assembly 52 as the shock from hitting an obstruction, such as a curb or 
tree, moves back through the caddie. Moreover, even if damage is caused to 
the caddie, the caddie is easily repaired due to the simplicity of the 
parts used in the caddie and the ease in assembling and dissembling the 
caddie. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.