Lumber work boat

A lumber work boat provided with an operating arm assembly at a bow portion of the boat for gathering up or moving lumber floating on the water. The boat has a recess to be opened frontwardly of the bow so that the operating arm assembly may be received within the recess, the assembly being driven by a drive mechanism disposed within the hull of the boat to transmit operating force to the operating arm assembly. The arrangement permits the entire work device to be positioned at a level lower than the upper deck, thereby providing a small type hull and enhancing mobility, while the operating arm assembly is protected since it is received in the recess when not in use, and the drive mechanism is not exposed to sea water or open air since it is encased within the hull.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to lumber work boats provided with an 
operating arm assembly for handling lumber at a bow portion of the boat. 
More particularly, the invention relates to a lumber work boat, in which 
at the bow portion there is formed a frontwardly open recess, within which 
the afore-mentioned operating arm assembly may be received, said operating 
arm assembly being driven by a drive mechanism disposed interiorly of the 
hull. 
2. Description of the Prior Art 
It is difficult to gather up or re-arrange lumber floating on the surface 
of the water, or to move the lumber from one position to another in a 
floating condition, and hence, lumber work boats are conventionally used 
to efficiently carry out such lumber handling operations. The lumber work 
boat is provided with a lumber handling device for handling lumber 
floating on the surface of the water, and this device may be power 
operated. The lumber work boat can handle the lumber efficiently, but in 
order to accomplish the work in more efficient and safe manner, the lumber 
work boat must be of the type which can turn in a small circle to allow 
the boat to freely and actively move in narrow waterways or between 
lumber, and which has high stability so that the boat may operate under 
stable conditions. 
In the known lumber work boats, the lumber handling device is usually 
disposed on the upper deck of the hull of the boat. Since the lumber work 
boat is constructed to be as small as possible to enhance its mobility, 
with a heavy work device disposed on the upper deck, the center of gravity 
of the entire boat is raised which decreases the stability of the boat. 
Usually, the work devices such as the lumber handling device are disposed 
at the bow portion. For this reason, the weight of the bow portion is 
increased to move the center of gravity of the entire boat forwardly, 
resulting in reduction of sea worthiness of the hull adversely affecting 
navigation, and difficulty in carrying out stabilized operation. 
If the work device is disposed on the upper deck, the height of the work 
device above the water surface is great, and therefore, for example, in 
the case where lumber on the water surface is gathered up at the broadside 
of a large boat, when the lumber work boat tries to come near the stern of 
the large boat, the work device comes into contact with the stern portion 
of the large boat, as a consequence of which the lumber flowing into the 
narrow portion of the stern portion of the large boat cannot be gathered 
up and in addition, the stern portion of the large boat may be damaged. 
Since a load is exerted upon the tip portion of the work device during 
operation, the construction of the boat where the work device is mounted 
must be made rigid when the latter is disposed on the upper deck. However, 
if the mounting portion for the work device employs a rigid construction, 
such portion will increase in weight because of the provision of such 
construction, whereby it is difficult to maintain the weight balance of 
the hull of the boat. 
Furthermore, drive devices such as hydraulic cylinders adapted to drive the 
work device and precision machining members, such as bearings, used in 
support portions of the work device are disposed on the deck, whereby 
these devices and members easily rust and materially impair the durability 
of these devices and members. As a result, the hydraulic system is 
susceptible to damage and oil leaked through the damaged portions flows 
out onto the surface of the water to contaminate the water. 
SUMMARY OF THE INVENTION 
It is a primary object of the present invention to provide a lumber work 
boat in which the work device is disposed at a position below the upper 
deck. 
It is a further object of the invention to provide a lumber work boat in 
which the work device is received in a recess formed in the hull when not 
in use thereby to overcome inconveniences at the time of navigation. 
It is another object of the invention to provide a lumber work boat in 
which a drive means for driving the work device is disposed interiorly of 
the hull of the boat, and the driving force from the drive means is 
transmitted as an operating force to the work device by a transmitting 
means which extends water-tightly between the interior and the exterior of 
the hull. 
According to the present invention, a frontwardly open recess is formed at 
a bow portion of the hull of the lumber work boat. This recess may be 
formed by integrally mounting a recess forming frame body, which comprises 
a pair of right and left side plates and a back plate, on the hull of the 
boat. The work device includes an operating arm assembly for handling 
lumber, the assembly being rotatable about a horizontal axis of rotation 
disposed in the recess so that the assembly may be rotated frontwardly 
from the interior of the recess into an operative position whereas it may 
be received into the recess when out of operation. An operating arm which 
forms part of the operating arm assembly may be of hollow construction, 
whereby the work device may be light-weight, and when the work device is 
submerged under the surface of the water, a great buoyancy is exerted 
thereupon to enhance the sea worthiness of the lumber work boat to assure 
stable navigation. The base end of the operating arm assembly may be of 
simply mountable construction so that the operating arm assembly may 
suitably be removed as a unit assembly from the interior of the recess. 
Thereby, replacement of the operating arm assembly may readily be 
achieved, and in addition, during navigation the operating arm assembly 
may also be removed in entirety. 
Furthermore, according to the present invention, the drive device for 
driving the operating arm assembly is disposed interiorly of the hull, and 
the transmitting means extends through the side plates of the recess 
forming frame body in water-tight condition to transmit the driving force 
of the drive device within the hull to the operating arm assembly. Thus, 
the drive device is prevented from being exposed to sea water and open air 
which may otherwise significantly impair its durability due to the 
formation of rust and corrosion. In addition, even if oil in the hydraulic 
system should leak, the oil would not run out onto the water surface since 
it is sealed in the hull of the boat. 
The hull may be provided with a propeller in a position frontwardly of the 
bottom of the boat, which can direct thrust in all directions, thereby to 
increase the mobility of the lumber work boat. Furthermore, the propeller 
may be surrounded by a protection screen so as to be protected from 
driftwood or other obstacles on the surface or in the water. 
Further objects and features of this invention will become apparent from 
the following description and from the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Turning now to FIGS. 1 and 2, the hull 1 comprises a deck 2 and a bottom 
wall 3, and disposed in a position downwardly and frontwardly of the 
bottom wall 3 is a propeller 4 which can turn to apply thrust in all 
direction. The propeller 4 has its circumference surrounded by a 
protection screen 5, and a steering arrangement S is provided interiorly 
of the hull 1 to turn the propeller in a suitable direction. 
The hull 1 has a bow portion provided with a recess forming frame body 6 so 
as to form a frontwardly open recess in the hull 1. This recess forming 
frame body 6 comprises a side plate 7 fixedly mounted together with a 
reinforcing member 14 on a left-hand broadside plate of the hull 1, a side 
plate 8 fixedly mounted together with a reinforcing member 15 on a 
right-hand broadside plate of the hull 1, a back plate 9 connected to the 
deck 2 and bottom wall 3, and a rearwardly projecting projection 10. The 
side plates 7 and 8 have front edges projecting frontwardly beyond the 
right and left broadside plates, respectively, of the hull 1, the front 
edges having front end surfaces formed with saw-tooth work surfaces 11 and 
12, respectively. Downwardly of the side plates 7 and 8 is formed an 
opening 13 to alleviate fluid resistance as the hull 1 moves sidewise. 
The side plates 7 and 8 are formed therein with flanged supporting holes 16 
and 17, respectively, the supporting hole 16 in the side plate 7 pivotally 
supporting a hollow pivot arm 20 of a base rotary body 18 having a 
mounting flange 19, and the supporting hole 17 in the side plate 8 
pivotally supporting a hollow shaft 23 of a supporting plate 22, which is 
firmly received in a hole 21 made in the base rotary body 18 and is 
rotated integrally with the base rotary body 18. Seal members are 
interposed between the hollow pivot arm 21 and the supporting hole 16 and 
between the hollow shaft 23 and the supporting hole 17, whereby the hollow 
pivot arm 20 and the hollow shaft 23 may be rotated as a rotating shaft of 
the base rotary body 18 in a water-tight condition in integral 
relationship with the side plates 7 and 8 and hence, the hull 1. 
The supporting plate 22 has a drive device 24 integrally secured thereto, 
and a pinion gear 26 in engagement with a rack 25 hydraulically 
reciprocable within the drive device 24 is secured to one end of a 
rotating shaft 27 which extends in the hollow pivot arm 20 and the hollow 
shaft 23 for free relative rotation. At the middle of the rotating shaft 
27 there is fixed an operating wheel 28, which is provided with a 
projecting arm 29, integral with the rotating shaft 27. Thus, the base 
rotary body 18 forms a first rotary body which rotates relative to the 
hull 1, whereas the rotating shaft 27 forms a second rotary body which is 
driven by the drive device 24 rotating integrally with the first rotary 
body and rotatable relative to the first rotary body. 
Key-fitted on the end of the hollow pivot arm 20 projecting from the side 
plate 7 towards the inside of the hull 1 is a rotating wheel 30 having a 
rotatable arm 31, which is prevented from being disengaged by a washer 32 
secured to the end of the rotating shaft 27. A pivot pin 39 fitted in a 
flanged hole 38 in the tip portion of the projection 10 of the recess 
forming frame body 6 has a hollow rotating shaft 36 with crank arms 37 and 
42 rotatably fitted therein, the hollow rotating shaft 36 being retained 
by washers 40 and 41 secured to the opposite ends of the pivot pin 39. A 
connecting rod 33 has one end pivotally connected by means of a pivot pin 
35 to the tip portion of the crank arm 37 and the other end pivotally 
connected to the tip portion of the rotatable arm 31 of the rotating wheel 
30 by means of a pivot pin 34. The tip portion of the crank arm 42 is 
pivotally connected, by means of a pivot pin 43, to the free end of a rod 
46 of a hydraulic cylinder 45 supported on a bracket 44 secured to the 
bottom wall 3 of the hull 1. 
Thus, the hydraulic cylinder 45 forms a first drive device which serves to 
rotate the base rotary body 18, which is a first rotary body, with respect 
to the hull 1 through the crank arms 42, 37, the connecting rod 33, and 
the rotatable arm 31, whereas the drive device 24 forms a second drive 
device which serves to rotate the rotating shaft 27, which is a second 
rotary body, relative to the base rotary body 18. 
A base end of a hollow operating arm 47 is removably mounted by means of a 
plurality of fixing bolts on the base rotary body 18 by utilization of the 
mounting flange 19 of the base rotary body 18 and a mounting flange 48 of 
the operating arm 47. A portion near the base end of a work pawl 49 having 
an acute tip portion a and a saw-tooth work surface 51 adjacent thereto on 
the side of the tip portion is pivotally connected to the tip portion of 
the operating arm 47 by means of a pivot pin 50. An operating rod 53 has a 
tip portion pivotally connected by means of a pivot pin 52 to the base end 
of the work pawl 49 and rod 53 extends towards the base of the operating 
arm 47 along the arm 47 and is removably connected at the base end thereof 
to the tip portion of the projected arm 29 by means of a pivot pin 54. 
Details of the drive device 24 are shown in FIGS. 3, 4, and 5. Referring 
first to FIG. 3, the drive device 24 is internally formed with a 
cylindrical internal hole 55 having opposite ends thereof provided with 
ports 56 and 58, respectively, the cylindrical internal hole 55 axially 
slidably receiving therein rack 25 having a tooth-face 60 in engagement 
with pinion gear 26 rotated within a recess 61. Referring to FIGS. 4 and 
5, an oil feed pipe 57 in communication with the port 56 is connected to 
an oil feed pipe 62 through a connecting element 63, whereas an oil feed 
pipe 59 in communication with the port 58 is connected to an oil feed pipe 
64 through a connecting element 65. The oil feed pipes 62 and 64 are in 
communication with an oil pressure source (not shown), and pressure oil is 
introduced into the port 56 or port 58 by an oil pressure change-over 
device (not shown) to axially move the rack gear 25 accordingly, thereby 
rotating and driving the pinion gear 26. It is noted that the oil feed 
pipes 57, 59, 62 and 64 are each free to undergo relative motion and may 
cooperate with the connecting elements 63 and 65 to enable permitting the 
relative rotational motion of the drive device 24 with respect to the hull 
1. 
From the foregoing arrangement, it will be appreciated that when the 
hydraulic cylinder 45, i.e. the first drive device, is retracted in a 
state where the hollow operating arm 47 is received within the recess 
formed by the recess forming frame body 6 as indicated by the chain-dotted 
lines in FIG. 1, the base rotary body 18, i.e. the first rotary body, is 
rotated, and at the same time, the operating arm 47 is frontwardly rotated 
as shown by the solid lines in FIG. 1. At this time, the drive device 24, 
i.e. the second drive device, is integrally rotated along with the base 
rotary body 18 and the operating arm 47. The drive device 24 is driven and 
operated independently of the hydraulic cylinder 45. Then, when the drive 
device 24 is driven, the rotating shaft 27, i.e. the second rotary body, 
rotates relative to the base rotary body 18 with the result that the 
projecting arm 29 rotates so that the work pawl 49 responsive to the 
projecting arm 29 through the operating rod 53 rotates relative to the 
operating arm 47. 
Thus, the hydraulic cylinder 45 and the drive device 24 are driven in 
cooperation with each other, whereby lumber W afloat on the water surface 
H may be moved while being held between the saw-tooth work surfaces 11 and 
51, or the work pawl 49 may be operated to gather up scattered lumber, or 
the acute tip portion a of the work pawl 49 may be utilized to orderly 
arrange the lumber on the water surface. 
The operating arm 47, the work pawl 49 and the operating rod 53 constitute 
an operating arm assembly. When the operating arm assembly is desired to 
be received in the recess in the bow portion after the operation has been 
completed, the assembly may be received in place in a state as indicated 
by the chain-dotted lines in FIG. 1, by expanding the the hydraulic 
cylinder 45 and at the same time by driving the drive device 24. 
The operating arm 47, which is of hollow construction, is useful in making 
the operating arm assembly a light weight structure, and when the 
operating arm is submerged, the action of buoyancy exerted upon the 
submerged portion may effectively be utilized to stabilize the bow portion 
and to enhance sea worthiness. 
Since the operating arm 47 is removably mounted on the base rotary body 18 
and the operating rod 53 is pivotally and removably supported with respect 
to the projecting arm 29, the operating arm assembly and the members which 
constitute the same can be replaced in easy manner. In the case of 
long-distance navigation and where the operating arm assembly is not used 
for a long period of time, the operating arm assembly may be removed in 
order to alleviate the weight at the bow portion so as to assure safe 
navigation, and protect the operating arm assembly. 
As is obvious from the foregoing description, it will be understood from 
the present invention that because of the provision of the frontwardly 
open recess at the bow portion for support of the operating arm assembly 
within the recess, the entire work device may be disposed at a low 
position with respect to the hull, whereby the hull may be of a small 
type, without impairing the stability, to reduce the turning circle and 
the mobility and to provide balance for the accomplishment of safe 
operations. Moreover, since the operating arm assembly may be received 
within the recess, the operating arm assembly can be protected, and the 
buoyancy, which is exerted upon the portion where the operating arm 
assembly is submerged, may be utilized to alleviate the weight carried by 
the bow portion. 
Further, according to the present invention, since the drive device is 
disposed interiorly of the hull, and the operating force transmitting 
means extends between the interior of the hull and the recess in 
water-tight condition to transmit the driving force of the drive device 
for the operation of the operating arm assembly, the drive device is 
prevented from being exposed to sea water and open air and is prevented 
from becoming significantly impaired in durability due to the presence of 
rust and corrosion, and even if oil, such as, working oil or lubricating 
oil should leak from the hydraulic system, the oil would not run out onto 
the water surface to cause contamination of the surface of the water since 
the oil is sealed in the hull.