Tractor cabin

A tractor cabin having struts, a top framework, an air conditioner mounted on the top framework, and a ceiling assembly covering an entire ceiling area of the cabin. In order to optimize air conditioned flows, the ceiling assembly includes outlet vents in a front region thereof for delivering defrosting air flows, outlet vents in lateral sides thereof for delivering air flows for the driver, an inside air intake vent in a rear portion thereof inside the cabin, and an outside air intake vent rearwardly and outwardly of the cabin. The ceiling assembly further includes an overhead console box having an air conditioning control unit and other elements. The console box is disposed such that its lower end is on or above a straight line extending from the driver's eye level to the top edge of a windshield to provide the driver with an unobstructed forward view.

BACKGROUND OF THE INVENTION 
The present invention relates to a tractor cabin and more particularly to 
an upper structure of the tractor cabin. 
It has been desired in recent years to provide the driver with a more 
comfortable environment inside the tractor cabin. As a first step to this 
end an air conditioner has been introduced. The air conditioner usually is 
mounted in a ceiling area of the cabin for effective use of the space. For 
conventional tractor cabins, however, enough consideration has not been 
made with respect to the arrangement of outlet and inlet vents of the air 
conditioner, air conditioned flows inside the cabin or to the obstruction 
to the driver's field of view by an enlarged ceiling area resulting from 
the installation of the air conditioner. In other words, it has heretofore 
been a basic concept to simply mount the air conditioner in the ceiling 
area of the tractor cabin and supply air conditioned flows into the cabin 
interior. The prior art practice has been totallly destitute of an 
approach from the point of view of human engineering. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a tractor cabin employing 
a human engineering approach, realizing optimal air conditioned flows for 
the driver, and having an well-adapted ceiling. 
The tractor cabin according to this invention includes an air conditioner 
mounted in a ceiling area and having outlet vents in a front portion and 
lateral portions and an intake vent in a rear portion of the cabin 
interior. This arrangement of the vents produces downward flows of air 
supply in the front and lateral portions of the cabin interior and upward 
flows of air withdrawal in the rear portion of the cabin. The driver is 
now free from the discomfort of air conditioned flows directly hitting 
certain parts of his body. 
According to a further aspect of the invention, the ceiling of the cabin 
includes an overhead console box having a bottom end thereof located on or 
above a straight line extending from the eyes of a seated driver to a 
lower edge of an upper front portion of a windscreen mounting element. 
This construction assures a sufficient accommodating capacity of the 
overhead console without reducing the driver's field of view. 
In a preferred embodiment of the invention, the tractor cabin includes 
front outlet vents adapted to direct air flows threfrom against the 
windshield, side outlet vents adapted to direct air flows therefrom toward 
the driver, and an air conditioner adapted to supply hot air into a first 
duct in communication with the front outlet vents and to supply a mixture 
of hot air and cold air into second ducts in communication with the side 
outlet vents. According to this embodiment, the air flows delivered from 
the front outlet vents have a defrosting function with respect to the 
windshield and the air flows delivered from the side outlet vents provide 
comfort for the driver. 
In another preferred embodiment of the invention, a tractor cabin includes 
an elastic support member for supporting a top covering of the cabin from 
below. This support member is mounted between a top framework carrying the 
air conditioner and the top covering, and is secured to a cross member 
attached to the top framework so as to straddle the air conditioner. The 
top covering is formed to define a sufficient space between the top 
covering and the top framework to accommodate the air conditioner and 
other elements, and the above construction is effective to avoid the 
inconvenience of the top covering undergoing a plastic deformation with a 
central portion thereof caving in under some load such as snow. 
Other features and advantages of the present invention will be apparent 
from the following description to be had with reference to the drawings 
and from the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, a tractor shown therein comprises a cabin 1 embodying 
the present invention. The cabin 1 is mounted on a rear portion of a 
chassis 3. The tractor also comprises a bonnet 2 enclosing an engine, 
front wheels 4 and rear wheels 5. 
The cabin 1 has a framework defined by a main framework assembly 10 shown 
in FIG. 2. The main framework assembly 10 includes right and left front 
struts 11, right and left rear struts 12, right and left intermediate 
struts 13 and 14, right and left auxiliary rear struts 15, right and left 
auxiliary intermediate struts 16, and bottom frames 17. The main framework 
assembly 10 is fixed through the bottom frames 17 to cushioned mounting 
brackets secured to the chassis 3. Furthermore, the main framework 
assembly 10 is reinforced by plates and cross beams extending from one 
strut to another. Doors 6 are provided between the front struts 11 and the 
intermediate struts 13 and 14 for the driver to walk into and out of the 
cabin. A top framework 20 having a substantially rectangular shape in plan 
view and comprising a front frame 21, a rear frame 22 and side frames 23 
and 24 is connected at the four corners thereof to tops of the right and 
left front struts 11 and the right and left rear struts 12. The top 
framework 20 further comprises a cross member 25 which, together with 
other parts of the top framework 20, supports an air conditioner assembly 
30 as shown in FIG. 3. The air conditioner assembly 30 is covered by a top 
covering 7 secured at peripheral undersurfaces thereof directly or through 
brackets to the top framework 20 by bolts or other means. 
Number 27 is FIG. 3 denotes a support member for supporting a central 
portion of the top covering 7. The support member 27 comprises a length of 
channel steel 27a and attaching legs 27b welded to opposite ends thereof. 
This support member 27 is secured to mounting brackets 26 defined on the 
cross member 25 by means of bolts 28. P1 and P2 denote axes of the bolts 
28. As seen from FIG. 3, the support member 27 straddles the air 
conditioner assembly 30 mounted on the top framework 20. The support 
member 27 includes an elastic support element 29 formed of rubber, 
plastics or other elastic material and fitted in the channel steel 27a. 
The elastic support element 29, which preferably is compressed, has an 
upper face in contact with an underface of the top covering 7 to support 
the top covering 7 from below, allowing an elastic deformation but not a 
plastic deformation of the top covering 7 under a load acting thereon from 
above. Depending on the construction and size of the air conditioner 
assembly 30, the elastic support element 29 may be mounted directly on an 
upper face of the air conditioner assembly 30 thereby dispensing with the 
support member 27. 
The air conditioner assembly 30 comprises an air conditioner 31 having 
heating, cooling and defrosting functions, a front duct 32 for 
transmitting defrosting air, a right duct 33 and a left duct 34 for 
transmitting air conditioned comforting air flows, namely a suitable 
mixture of hot air and cold air, and a rear duct 35 for taking in air. The 
rear duct 35 has a blower unit 36 connected thereto to substantiate air 
intake for the air conditioner 31. 
As shown in FIG. 4, the cabin interior includes a control section 8 in a 
front portion and a driver's seat 9 in a rear portion thereof. Its ceiling 
area is entirely covered by a ceiling assembly 50 comprising a plastic 
material or the like. The ceiling assembly 50 may be coated with a heat 
insulating material as desired. Number 40 denotes a windshield which, as 
better shown in FIG. 5, has an element 54 formed of rubber fitted on 
peripheries thereof. A mounting member 55 fitted in the element 54 is 
secured to the front struts 11 and the side frame 21 of the top framework 
20. The windshield is slightly inclined rearwardly. 
An overhead console box 51 is provided in a front region of the ceiling 
assembly 50. An inclined portion 56 constituting a back plate of the 
overhead console box 51 defines right and left openings, and front outlet 
vent means 58 is removably secured in these openings by bolts. 
The front outlet vent means 58 comprises a mounting plate 59 bolted to the 
inclined portion 56, an outlet vent 60 having a spherical peripheral 
surface, and a retainer 61 fixed to the mounting plate 59 to rotatably 
support the outlet vent 60. 
The front outlet vent means 58 has a chamber 63 in the back thereof to 
which the front duct is connected. The front outlet vent means 58 is 
adapted to receive hot air or cold air from the air conditioner 31 and 
direct it against the windshield 40 through the outlet vent 60. The outlet 
vent 60 is rotatable relative to the retainer 61 to change directions of 
the air flows therefrom, thereby to vary positions of the windscreen 40 to 
which the air flows are directed. 
Since the front outlet vent means 58 comprises the inclined portion 56 
which rises forwardly, the air flows delivered from the outlet vent 60 may 
be selectively directed against a wide area of the windshield. The 
overhead console box 51 has a lower end 62 thereof located on or above a 
straight line A extending from the eyes of the driver seated on the seat 9 
to a lower edge of an upper portion of the element 54 mounted peripherally 
of the windshield 40. Therefore, the overhead console box 51 does not 
reduce the driver's upper forward field of view, whereby the driver has a 
good view of a front loader operation. 
Referring to FIG. 6, right and left lateral sides of the ceiling assembly 
50 also include known side outlet vent means 64. The side outlet vent 
means 64 each comprise two fore and aft outlet vents 65 for directing a 
mixture of hot air and cold air sideways toward the driver seated on the 
seat 9. The side outlet vent means 64 also have elongate chambers in the 
back thereof to which the right and left side ducts 33 and 34 are 
connected, respectively, to transmit air conditioned flows from the air 
conditioner 31 to the outlet vents 65. 
The ceiling assembly 50 further includes an inside air intake vent 66 at a 
rear portion thereof to take in air from the cabin interior. 
The cabin has a rear glass 41 inclined forwardly toward the intake vent 66. 
The ceiling assembly 50 has a rear end defining an overhanging projection 
53 which includes an outside air intake vent 67 in an under face thereof. 
The inside air intake vent 66 and the outside air intake vent 67 
constitute air intake vent means 70 connected to the blower unit 36. The 
blower unit 36 includes a damper 68 (FIG. 4) switchable between a position 
to connect the inside air intake vent 66 and a position to connect the 
outside air intake vent 67 to the air conditioner 31 through the rear duct 
35. 
Each of the side outlet vents 65 is provided with adjusting means for the 
driver to adjust the direction and amount of air flowing therefrom. 
Further, the side outlet vent means 64 includes dampers or the like for 
selectively supplying air to the side outlet vents 65. The overhead 
console box 51 includes, along with a radio and other devices, an air 
conditioning control unit 69 for effecting various adjustments of the 
dampers of the side outlet vent means 64, the damper 68 of the blower unit 
36, the adjusting means of the side outlet vents 65, and the air 
conditioner 31. 
FIG. 6 shows, by means of arrows, the defrosting air flows delivered from 
the front portion of the ceiling assembly 50, the conforting air flows 
delivered from the lateral sides both in front of and at the back of the 
seated driver, and the air flows withdrawn from the rear portion of the 
cabin interior. It will be understood that the invention provides an 
excellent environment of air conditioned flows in the cabin interior.