Vibration isolating mountings for push-pull cables coupled to vibrating control arms

A hydrostatic drive for a windrower includes wheel motors having speed control arms movable between "hi" and "lo" speed stops by means of a pair of push-pull cables coupled between the control arms and a speed control lever. The cables have housings mounted to the motor control arms so as to isolate the cable from noise and other vibrations induced in the control arms. The cable housings are also mounted to the frame by a shock absorber load assembly which acts through the cable housing to resiliently bias the control arms against their respective stops and to further isolate the cable from vibrations.

BACKGROUND OF THE INVENTION 
The present invention relates to the reduction of noise within a vehicle 
cab and more specifically relates to isolating the inside of a cab from 
noise generated by hydrostatic wheel drive motors. 
It is known, for example, to use a hand lever for controlling the speed of 
a pair of wheel motors of a hydrostatically driven windrower through the 
medium of a pair of push-pull cables respectively linked between the lever 
and respective speed control arms of the motors. In this known control, 
the core of each cable has opposite ends fixed to the lever and a 
respective motor speed control arm while the housing or sheath of the core 
is anchored to the vehicle frame. This known cable arrangement is not 
entirely satisfactory since fluid pulsations generated by the motors 
result in vibrations being induced in the control arms and then 
transmitted through the cable cores to the interior of the cab. Also, 
vibrations sometimes cause the motor control arms to migrate away from 
respective stops delimiting the "hi-lo" operating positions thereof and 
this results in a very disturbing growling type noise being produced by 
the motors. 
SUMMARY OF THE INVENTION 
According to the present invention there is provided a novel control 
arrangement for diminishing the transmission of noise from a 
cable-controlled device, which generates noise during operation, to a 
vehicle cab. 
It is an object of the invention to isolate a control lever, located in a 
vehicle cab, from noise generated by a device having a control arm coupled 
to the lever by a push-pull cable. 
A more specific object of the invention is to use elastomeric connectors 
between a device control arm and a cable housing to isolate the cable from 
vibrations induced in the control arm, with the cable core having opposite 
ends respectively coupled to the lever and anchored to the vehicle frame 
adjacent the control arm and with the cable housing being anchored to the 
frame at a location adjacent to the control lever. 
Yet, a more specific object of the invention is to provide a push-pull 
cable arrangement as described in a previous object wherein elastomeric 
connectors are used in anchoring the cable housing to the frame. 
Another specific object is to construct the elastomeric connectors of the 
immediately preceding object such that they act to establish a biasing 
force on the device control arm when the control lever is swung in 
opposite directions from a central position to respective operating 
positions to thereby hold the device control arm in corresponding 
operating positions. 
These and other objects, features and advantages of the present invention 
will become apparent to those skilled in the art from the description 
which follows and from the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, there is shown a self-propelled windrower 10. The 
windrower 10 has a main frame 12 supported on a pair of front drive wheels 
14 and a pair of rear castered wheels 16. The drive wheels 14 are driven 
by a hydrostatic drive system including a pair of variable speed motors 
18, partially shown in FIG. 2, respectively coupled to the wheels 14. A 
platform 20 is suspended from the forward end of the frame 12. Located on 
the forward portion of the frame 12 is an operator's cab 22 which contains 
all of the controls for the windrower. 
Referring now to FIGS. 2-5 there is shown a control system 24 for placing 
the motors 18 in either a high speed, "hi", transport condition or a low 
speed, "lo", working condition. Specifically, there is shown a 
manually-operated "hi-lo" shift lever 26 which has an upper end portion 
defined by a hand grip (not shown) and a lower end defined by an inverted 
U-shaped strap 30. The lever 26 is mounted for fore-and-aft pivoting 
movement about a horizontal transverse axis defined by a pin 32 extending 
through the lever between its opposite ends and coupling it to a support 
structure 34 located beneath a floor 36 of the cab. The floor 36 contains 
an opening 38 through which the lever extends. The lever is movable 
between "hi" and "lo" positions and held therein by an offset portion 40 
of a shift gate 42. 
A pair of push-pull cables 44 is coupled and each includes a bend section 
45 located between the lever 26 and a pair of speed control arms 46 of the 
motors 18 so as to transmit motion of the lever to each control arm 42 and 
move the latter against respective stops 47 and 48 which delimit 
corresponding "hi" and "lo" positions of the arms. Specifically, each 
cable 44 includes a core 50 slidably encased in a housing or sheath 52. A 
connector eye 54 is coupled to one end of each core 50 and is secured, as 
at 56, to a respective leg of the strap 30 forming the bottom of the 
"hi-lo" shift lever 26. The opposite ends of the cores 50 are respectively 
anchored to a pair of tabs 58 located on depending frame portions 60 
located at opposite forward end locations of the frame 12 and carrying the 
motors 18, the tabs 58 being located downwardly beyond but adjacent to the 
motors. 
The cable housings 52 terminate short of the opposite ends of the 
respective cores 50. The ends of the housings 52 which are closest to the 
shift lever 26 are anchored to the frame 12 by a shock absorber load 
assembly 62. Specifically, the assembly 62 includes a pair of two-piece 
clamps 64 respectively received about armored sections 66 of the pair of 
housings 52. A U-shaped cable mounting bracket or plate 68 has opposite 
fore-and-aft extending legs 70 and fixed to an outer surface of each of 
the legs are upper and lower vertically spaced retaining tabs 72 and 74. 
The pairs of clamps 64 respectively fit snugly between the set of tabs 72 
and 74 provided on the legs 70 and each clamp 64 includes a clamp bolt 76 
which extends through the two pieces of the clamp and one of the bracket 
legs 70. Fixed to the cab floor 36 is a support bracket 78 including a 
vertical transverse plate portion 80 which extends parallel to a vertical 
bight portion 82 of the U-shaped bracket 68. A fore-and-aft extending bolt 
84 carries a circular compression plate 86 at its head end and the bolt is 
received in fore-and-aft aligned holes located in the plate and bight 
portions 80 and 82. Received on the bolt 84 between the compression plate 
86 and the bight portion 82 is a first pair of cylindrical, elastomeric 
cushions 87 and received on the bolt between the bight portion 82 and the 
vertical plate portion 80 is a second pair of cylindrical elastomeric 
cushions 89. A nut and jam nut assembly 90 is received on a threaded 
forward end of the bolt and is adjustable so as to vary the biasing force 
acting on the motor control arms 46 in a manner set forth in more detail 
below. 
The ends of the cable housings 52 which are respectively closest to the 
motor control arms 46 are secured to these arms by respective vibration 
isolator assemblies 92. As can best be seen in FIG. 5, each of the 
assemblies 92 includes a pair of isolators 94 and 96 respectively mounted 
in a pair of spaced holes provided in an end of a respective motor control 
arm 46, the isolators each including inner and outer steel sleeves 
sandwiching an elastomeric core. The holes carrying the isolators 94 and 
96 are substantially aligned with the direction of movement of the cable 
housing 52 during actuation of the arm 46. A triangular plate 98 is bolted 
to each arm 46 by a pair of bolts 100 which extend through the inner 
sleeves of the associated isolators 94 and 96. A two-piece clamp 102 is 
received about an armored section 104 of each cable housing 52 and 
includes a clamp bolt 106 which extends through the clamp pieces and an 
associated one of the triangular plates 98. 
In operation, assuming the speed control lever 26 to be initially in an 
intermediate position between its "hi" and "lo" positions, as shown in 
FIG. 3, each of the shock absorber load assemblies 62 will be in a neutral 
condition wherein preload forces exerted on the cable mounting bracket 68 
by the sets or pairs of elastomeric cushions 86 and 88 will be balanced. 
Also, each cable core 50 will be positioned by the lever 26 so that the 
associated core 52 holds its associated motor control arm 46 in a position 
intermediate the "hi" and "lo" stops 47 and 48. 
If it is then desired to ready the windrower for transport, the lever 26 is 
pulled back into its "hi" position in the rearward end of the shift gate 
42. This lever movement will cause each of the cable cores 50 to be pulled 
leftwardly as viewed in FIG. 3 and thereby deflects the cable housings 52 
leftwardly so as to initially move the arms 46 against respective "hi" 
stops 47 and then to act through the clamps 64 and bracket 68 to further 
compress the pair of elastomeric cushions 88 of the shock absorber load 
assembly 62. Thus, the compressed cushions 88 act to resiliently load or 
bias the arms 46 against their stops 47 so as to ensure that they do not 
drift from their operating position during operation. Also, the compressed 
cushions 88 serve to accommodate wear in the various connections between 
the cable housings 52 and the bracket 78 and between the housings 52 and 
the arms 46. 
If it is then desired to place the windrower in condition for field 
operation, the lever 26 is moved forwardly to its "lo" position. This 
forward movement causes the cable cores 50 to be pushed rearwardly so as 
to deflect the cable housings 52 rearwardly to first unload the pairs of 
cushions 88, then move the arms 46 from their "hi" stops 47 to their "lo" 
stops 48 and then to compress the pairs of cushions 87 so that the arms 46 
are resiliently biased into position. 
The amount of loading exerted on the arms 46 when the lever 26 is in one or 
the other of its "hi" and "lo" positions may be varied by adjustment of 
the nut and jam nut assembly 90 on the end of the bolt 84 of the shock 
absorber load assembly 62. 
It will be appreciated that noise and other vibrations induced in the motor 
control arms 46 will be dampened by the associated isolators 94 and 96 so 
that they are not transmitted to the cable housings 52 and in this way are 
kept from being transmitted to the cores 50 and the control lever 26. 
Vibrations which are induced in the frame 12 are absorbed or dampened by 
the shock absorber load assembly 62. Thus, the push-pull cables 44 are 
mounted between the lever 26 and the motor control arms 46 in such a way 
as to at least significantly reduce the amount of noise generated in the 
cab due to motor and other vibrations traveling along the cables to the 
control lever 26.