Combination tool for removing and replacing a nut

A combination tool comprises an elongated lever having a handle at one end, two divergent fingers at the other end, and an aperture between the two ends adapted for engagement with a nut. One of the fingers includes a distal end and claw in spaced relationship thereto which cooperate to provide a fulcrum for movement of the lever, thereby to facilitate the removal and replacement of nuts which are locked on a threaded shaft by a locking member having bendable tabs projecting outwardly therefrom.

The present invention relates to hand tools adapted for use in confined 
spaces, and more particularly, to a tool for facilitating the removal and 
replacement of a propeller which is mounted on a threaded drive shaft 
within the confines of a shroud. 
Various tools have been developed for use in removing and replacing a nut 
which is locked on a threaded shaft in a confined space by a locking 
member having bendable tabs projecting outwardly therefrom. One particular 
application for such tools is in the removal and replacement of a 
propeller mounted on a threaded drive shaft of a boat engine. Generally, 
the propeller is mounted to the shaft by a nut which is locked on the 
shaft by a locking member having bendable tabs. The nut and locking member 
are secured to the shaft in the confined space of a shroud which carries 
the propellers and encompasses the shaft. 
Tools particularly adapted for performing such operations in connection 
with motor boat engines are disclosed in U.S. Pat. Nos. 3,623,172 and 
4,089,077. While such tools facilitate the task of removing and replacing 
propellers, they still have various deficiencies. For example, the 
structure and method of operation of both of the tools disclosed in these 
patents make it possible for them to disengage when bending one of the 
tabs of the locking member. The wrench portion of each of the tools 
disclosed in these patents is located in proximity to an end so that the 
tool must be reversed or rotated in order to use the wrench portion. No 
single handle portion is provided for use in performing all functions of 
the tool. Further, while these tools provide some mechanical advantage for 
bending the tabs of the locking member, considerable force must still be 
exerted on the tool to perform the bending operations. 
Other combination tools are disclosed in U.S. Pat. Nos. 657,075; 904,572; 
and 2,898,674; however, none of these tools suggest ways to effectively 
improve the tools disclosed in U.S. Pat. Nos. 3,623,172 and 4,089,077. 
One object of the present invention is to provide an improved combination 
tool which may be used more efficiently in removing and replacing 
propellers fixed to drive shafts of boat motors. 
Another object of the present invention is to provide an improved 
combination tool that is simple in construction, economically and 
commercially feasible to manufacture, and durable and reliable in 
operation. 
A further object of the present invention is to provide an improved 
combination tool which is a single rigid unit and where the structure and 
method of operation of the tool effectively increase its stability in 
relation to prior tools. 
Yet another object of the present invention is to provide an improved 
combination tool where the force needed to perform the bending operations 
is effectively decreased through a novel arrangement which increases the 
mechanical advantage in relation to prior tools. 
In one illustrative embodiment, the combination tool of the present 
invention comprises an elongated lever having a first end section 
including a handle, a second end section including first and second 
divergent fingers, and a wrench section interposed between the two end 
sections. A first finger includes a generally planar end and a claw 
extension adjacent to the planar end for engaging upper and lower 
surfaces, respectively, of one of the tabs of a locking member. The planar 
end of the first finger, in cooperation with the upper surface of the one 
tab, provides a fulcrum for movement of the lever, thereby to bend the one 
tab upward. A second finger projects outwardly slightly further than the 
claw extension of the first finger for engaging an upper surface of the 
one tab. The planar end of the first finger, in cooperation with the upper 
and lower surfaces of a tab opposed to the one tab provides a fulcrum for 
movement of the lever, thereby to bend the one tab downward.

Referring now to FIG. 1, the combination tool of the present invention is 
an elongated lever 10 which includes a proximal end section 12, a distal 
end section 40, and a wrench section 20 provided between the two end 
sections 12, 40. The lever 10 is a single unit which may be fabricated 
from a rigid material, such as metal, and may be stamped from a sheet of 
the rigid material as opposed to being cast in a die. 
The proximal end section 12 of the lever 10 provides a tang for receiving a 
grip 14 which is sleeved over the tang to form a handle for manipulation 
of the tool in performing its several functions. Grip 14 may be fabricated 
from any flexible material, such as rubber or a soft plastic. 
The wrench section 20 is canted from the end sections 12, 40, and is 
integrally joined thereto by a first web portion 22 which extends 
angularly downwardly from the proximal end section 12 and a second web 
portion 24 which extends angularly downwardly from the distal end section 
40. As best shown in FIG. 5, the wrench section 20 is offset from the 
plane of the end sections 12, 40. The wrench section 20 also includes a 
third web portion 26 which is in a plane 28 in spaced parallel 
relationship to the plane of the end sections 12, 40. The third web 
portion 26 includes a hexagon-shaped aperture 30 which lies in the plane 
28 and a downwardly projecting alignment detent 32 positioned adjacent to 
one edge of the third web portion 26. The function of the wrench section 
20 will be described in detail in the description of the use and operation 
of the tool. 
Continuing to refer to FIG. 1, the distal end section 40 of the lever 10 
includes two outwardly extending divergent fingers 42, 56. The two 
divergent fingers 42, 56 give the lever 10 a generally Y-shape appearance. 
A first finger 42 extends outwardly at an angle 43 of generally 30.degree. 
in relation to the longitudinal axis of the lever 10. The distal end 44 of 
the finger 42 includes a planar distal surface or edge 45 in a plane at 
generally a right angle to the longitudinal axis of the lever 10. A finger 
extension 46 is mounted to the finger 42 by rivets 48 or other well-known 
connecting means, and extends beyond the outer surface 45. The distal end 
50 of the finger extension 46 includes a claw 52 in spaced relationship to 
the surface 45. For reasons which will become apparent in the description 
of the use and operation of the tool, the distance between the surface 45 
and the claw 52 should be relatively small. 
A second finger 56 extends outwardly at an angle 57 of generally 30.degree. 
in relation to the longitudinal axis of the lever 10. The second finger 56 
is tapered toward its distal end 58 and has a generally rounded distal 
surface. 
The two divergent fingers 42, 56 are separated by a generally U-shaped 
outwardly opening space 60. An intermediate surface 62 integrally joins 
the two fingers 42, 56 at generally a right angle to the longitudinal axis 
of the lever 10. Measured from the intermediate surface 62 along the 
longitudinal axis of the lever 10, the length 64 of the second finger 56 
is slightly greater than the combined length of the first finger 42 and 
finger extension 46. The advantages of each of these features of the tool 
will become apparent in the description of its use and operation which 
follows. 
The use and operation of the combination tool can best be described by 
referring to FIGS. 2-5 wherein like reference numerals are used throughout 
the various views to indicate like parts. The tool of the present 
invention is particularly adapted for use in confined spaces to remove and 
replace a nut which is locked on a threaded shaft by a locking member 
having one or more bendable locking tabs projecting outwardly therefrom. 
Typically, the tabs of the locking member are bent downwardly into one or 
more of a plurality of radially extending angularly spaced grooves to 
prevent turning of the nut after it has been tightened onto the threaded 
shaft. In order to unlock the nut and allow it to be turned for removal, 
the tabs must be bent upwardly out of the grooves. In confined spaces, 
these bending operations are difficult to perform. 
One illustrative example of the use for the combination tool is in the 
removal and replacement of a propeller mounted on a drive shaft of a boat 
motor where the connection between the propeller and shaft is confined 
within an encompassing shroud or housing. As shown in FIGS. 2-5, a 
conventional propeller hub assembly includes a splined drive shaft 70 
having its distal end externally threaded and a propeller hub 74 having a 
splined connection with the shaft 70. This assembly is encompassed by a 
shroud or housing 76 which is generally cylindrical and carries a 
plurality of radially outwardly projecting propeller blades 78, as best 
shown in FIG. 4. The shroud 76 is connected in spaced relationship to the 
propeller hub 74 by braces 80 and completely surrounds the propeller hub 
assembly so that the shaft 70 and propeller hub 74 are located within a 
relatively limited space 82 defined by the shroud 76. 
The propeller hub 74 is secured to the propeller drive shaft 70 by an 
internally threaded hexagon-shaped nut 90 which threadably engages the 
threaded distal end 72 of the drive shaft 70. The nut 90 is locked in 
place after it is tightened to prevent removal of the propeller hub 74 by 
a lock washer 92 having a hexagon-shaped depression 94 for receiving the 
hexagon-shaped nut 90. The lock washer 92 includes a plurality of 
outwardly projecting bendable tabs 96, each adapted to be bent into one of 
a plurality of radially disposed, angularly spaced grooves 98 formed 
between castellated portions 100 of a splined washer 102 which has a 
splined connection with the drive shaft 70 and which bears against the 
propeller hub 74. The splined washer 102 includes a circular-shaped 
depression 104 for receiving the lock washer 92 so that it may rotate 
freely relative to the splined washer 102 until a tab 96 is bent into one 
of the grooves 98. 
Referring particularly to FIGS. 2 and 5, when it is desired to assemble or 
replace the lock washer 92 and nut 90 on the drive shaft 70, the lock 
washer 92 is positioned in the circular-shaped depression 104 of the 
splined washer 102, and the nut 90 is threaded onto the drive shaft 70 
with the wrench section 20 of the lever 10. Since the wrench section 20 is 
canted from the end sections 12, 40 of the lever 10, it effectively 
engages the nut 90 within the space 82 defined by the shroud 76, and the 
ends 12, 40 are elevated external to the shroud 76 to allow unobstructed 
rotational movement of the lever 10 in a clockwise direction for 
tightening the nut 90 onto the drive shaft 70. 
As the nut 90 is tightened onto the drive shaft 70, it is important that 
the hexagon-shaped nut 90 be properly aligned with the hexagon shape of 
the depression 94 in the lock washer 92 in order to lock the nut 90 on the 
shaft 70. The downwardly projecting alignment detent 32 adjacent the edge 
of the wrench section 20 of the lever 10 serves to align the nut 90 with 
the depression 94 as the lever 10 is rotated to tighten the nut 90 on the 
shaft 70. The alignment detent 32 is positioned relative to the 
hexagon-shaped aperture 30 in the wrench section 20, so that as the lever 
10 is rotated, the detent 32 engages one of the outwardly projecting tabs 
96 of the lock washer 92 to align the hexagon-shaped aperture 30 with the 
hexagon-shaped depression 94 of the lock washer 92. Further rotation of 
the lever 10 with the alignment detent 32 engaging a tab 96 of the lock 
washer 92 causes the nut 90 and lock washer 92 to be rotated 
simultaneously with the aperture 30 and depression 94 properly aligned so 
that the nut 90 is positioned in the depression 94 as it is being 
tightened onto the shaft 70. 
After the nut 90 has been tightened onto the drive shaft 70, selected tabs 
96 of the lock washer 92 are bent downwardly into associated grooves 98 on 
the splined washer 102 in the manner shown in FIG. 2. By hooking the claw 
52 of the finger extension 46 on the lower surface of a tab 96 
diametrically opposed to the selected tab 96 so that the planar distal 
surface 45 of the finger 42 engages the upper surface of the opposed tab 
96, a fulcrum 110 is provided between the finger 42 and the opposed tab 96 
for movement of the lever 10. As the lever is moved in the direction of 
the arrow in FIG. 2, the second finger 56 engages the selected tab 96 so 
that further movement of the lever 10 bends the selected tab 96 downwardly 
into an associated groove 98 of the splined washer 102. The entire lever 
10 pivots about the fulcrum 110 formed by the engagement of the finger 42 
with the upper surface of the diametrically opposed tab 96. It should be 
noted that the outwardly opening space 60 separating the fingers 42, 56 is 
large enough to receive the nut 90 during the movement of the lever 10. 
During the bending operation, the lever 10 does not engage either the 
shaft 70 or the nut 90. This operation is repeated with each selected tab 
96 of the lock washer 92 to lock the nut 90 against rotation once it has 
been tightened onto the drive shaft 70. 
In order to remove the nut 90 from the propeller shaft 70, it is necessary 
to straighten each downwardly bent tab 96 of the lock washer 92 by bending 
it upwardly so that the tabs 96 are disposed in a plane substantially 
parallel to the axis of rotation of the nut 90. 
As shown in FIGS. 3 and 4, the tabs 96 may be bent upwardly or straightened 
by inserting the claw 52 of the finger extension 46 against the lower 
surface of a downwardly bent tab 96 so that the planar distal surface 45 
of the finger 42 engages the upper surface of the downwardly bent tab 96. 
The cooperation between the planar surface 45 of finger 42 and the upper 
surface of the downwardly bent tab 96 provides a fulcrum 112 for movement 
of the lever 10 in the direction of the arrow in FIG. 3. The entire lever 
therefore pivots about the fulcrum point 112. During this bending 
operation, the lever 10 does not engage either the shaft 70 or the nut 90. 
Since the distance between the fulcrum point 112 and the claw 52 of the 
finger extension 46 is substantially less than the distance between the 
fulcrum point 112 and the handle 14 of the lever 10, the mechanical 
advantage for prying the tab 96 upwardly is significantly greater than 
conventional tools adapted for the same purpose. Therefore, less force is 
required to move the lever 10 and bend the tab 96 upwardly. 
As shown in FIG. 4, it may be desirable to radially offset the second 
finger 56 from the tab 96 diametrically opposed to the downwardly bent tab 
96 being pried upwardly to assure that the downwardly bent tab 96 is 
completely straightened and disposed in the plane substantially parallel 
to the axis of rotation of the nut 90. It should be noted that the 
downwardly bent tab 96 may be effectively straightened without offsetting 
the second finger 56; however, the offset position of the second finger 56 
is a preferred position in performing the prying operation of the tool. 
Once each of the downwardly bent tabs 96 have been bent upwardly and 
straightened so that they are adjacent the end surface of the splined 
washer 102, the nut 90 may be unscrewed from the drive shaft 70 by again 
engaging the wrench section 20 of the lever 10 with the nut 90 and 
rotating the lever 10 in a counterclockwise direction to remove the nut 90 
from the drive shaft 70.