Log splitter

A portable log splitter having a hydraulic cylinder for applying force to a log wherein the source of hydraulic fluid is a pump driven by a detachable power plant of the type used for chain saws. The cylinder is a two way cylinder which moves faster in the retracting direction than in the force applying direction to speed up the cycle of log splitting and the cutting blade is provided with guide members which permit a split to be completed with a short power applying stroke.

This invention relates to apparatives for splitting logs and particularly 
to a power driven, hydraulic log splitter. 
Log splitters have been provided in which a force generated by a hydraulic 
cylinder has been used to split logs and when such log splitters are 
powered with engines or the like they become relatively heavy and as a 
consequence can be transported only with difficulty. As a result most such 
log splitters are supported on wheels so that they can be towed to and 
from a site at which logs are to split. This makes such splitters large 
and relatively expensive. 
Log splitters often are used in conjunction with chain saws. The chain saws 
are used to fell trees and to cut the trunks of trees to appropriate 
lengths which subsequently are to be split. It would be highly desirable 
and as a consequence it is an object of this invention to provide a 
powered, hydraulic log splitter which uses the power source of the chain 
saw as the power source for the log splitter. 
Another object of the invention is to provide a log splitter which is 
relatively light and which can be separated into two or more parts making 
the log splitter portable. 
Another object of the invention is to provide a log splitter with a 
splitting arrangement so arranged that a minimum amount of hydraulic 
stroke is required to split. 
The objects of the invention are accomplished by a log splitter in which a 
hydraulic actuator is supported on a base member to move a log against a 
splitting blade. The actuator is provided with hydraulic fluid under 
pressure from a hydraulic pump which is driven by a detachable power plant 
of the type used to power chain saws by substituting a driving chain from 
the power saw power plant to a hydraulic pump for the usual toothed 
cutting chain used on the chain saws. The power plant is rapidly 
detachable from the log splitter and the log splitter itself is separable 
into subassemblies which facilitate storage and transport.

The hydraulic log splitter embodying the invention is designated generally 
at 10 and includes an hydraulic actuator 12 and a blade assembly 14 for 
engaging and penetrating a log which is pushed against the blade assembly 
14 by the hydraulic actuator 12. The hydraulic actuator 12 and the blade 
14 are mounted on a base assembly 16 which includes telescoping tubular 
members 18 and 20 having generally square, complementary cross sections. 
The smaller tube 18 telescopes within the larger tube 20. As seen in FIG. 
1, the base assembly 16 is in a partially extended position and is held in 
that position by a pin 22 which passes through aligned openings in 
opposite walls of the tube 20 and through selected openings 24 in tube 18. 
This makes it possible to change and adjust the distance between the 
hydraulic actuator 12 and the blade assembly 14 for accomodating various 
sizes of logs during splitting operations or if desired, the pin 22 can be 
removed to collapse the base 16 or to separate the tubes 18 and 20 for 
storage or transport purposes. 
The tube 20 is provided with transversely extending legs 26 and tube 18 is 
provided with a single transversely extending leg 27 which stabilizes the 
base assembly 16 on the ground. 
The end of the smaller tube 18 has a vertical tubular bracket member 28 
which locates and supports the blade assembly 14. The blade assembly 14 
includes a toothed member 30 and a spreader member 32. The blade 30 has a 
plurality of teeth 34 and is held to the tube 18 by a means of a 
vertically extending bolt 36 anchored in the tube 18 and a pair of studs 
38 which pass through a wall of a bracket 28, through the spreader 32 and 
into threaded openings formed in the toothed member 30. 
The teeth 34 have triangular faces and form a sawtoothed arrangement that 
can be made of a single integral block of metal. If preferred, the teeth 
34 can be made separate as disclosed more completely in patent 4,157,105 
granted June 5, 1979. 
The hydraulic actuator 12 serves to move logs against the blade assembly 14 
during the splitting operation and is mounted on the larger tube 20 of the 
base 16. The hydraulic actuator 12 is held in position by a pair of 
U-bolts 40 which pass over cylinder 42 of the actuator so that one end of 
the cylinder 42 is held against a vertical bracket 44 fixed as by welding 
or the like to one end of the tube 20. 
The hydraulic actuator 12 includes a piston 46 to which is attached a 
relatively large, hollow rod member 48 mounted to slide in an end wall 50 
of the hydraulic actuator 12. The piston 46 and rod member 48 divide the 
cylinder 42 into a relatively large chamber 52 at one side of the piston 
46 and a substantially smaller chamber 54 at the rod side of the piston 
46. Delivery of hydraulic fluid under pressure to the large chamber 52 
causes the rod member 48 to extend from the cylinder 42 and at the same 
time forces hydraulic fluid from the smaller chamber 54. Similarily, 
delivery of hydraulic fluid to the small chamber 54 retracts the rod 
member 48 and exhausts hydraulic fluid from the large chamber 52. 
The end of the rod member 48 opposite to the piston 46 is provided with a 
pad 56 rigidly fastened to the end wall of the rod member 48. As seen in 
FIG. 5, the pad 56 is guided during movement of the rod member 48 by 
channel shaped guides 60 which receive flanges 62 formed on opposite sides 
of the base tube 20. 
A pump assembly 64 for supplying hydraulic fluid to the actuator 12 can be 
any suitable hydraulic pump 65. In an actual embodiment of the invention a 
geared type pump manufactured by Webster Manufacturing Co. and identified 
by Model 172-86164 was used successfully. Pump 65 is mounted at one end of 
a tank 66 which forms a reservoir for the hydraulic system. The pump 65 is 
of the rotary gear type and is driven by a shaft 68 seen in FIG. 3. A 
plate 72 is fastened to the bracket 44 and also is fastened to the pump 
assembly 64 so that the shaft 68 projects from one side of the plate 72 
and drivingly supports a sprocket 76. The teeth of the sprocket 76 are 
engaged by and driven by a chain 78. The chain 78 is guided by a drive bar 
80 of the type commonly used with power driven chain saws although it may 
be substantially shorter than conventional chain saw drive bars. The drive 
bar 80 is bolted to the plate 72 and is provided with a slot 82 to receive 
the usual mounting bolt associated with chain saws for supporting the 
chain saw power plant 84 in the form of a gasoline motor relative to the 
drive bar 80. The chain 78 is substituted for the conventional toothed 
cutting chain of a chain saw and connects the power plant 84 in driving 
relationship with the pump 64. 
When the chain saw motor 84 is operated, the sprocket 76 rotatably drives 
the pump 64 and delivers hydraulic fluid under pressure through line 85 to 
a control valve 86. The control valve 86 is a three position four way 
valve which operates in its neutral position indicated with the handle at 
88 to recirculate hydraulic fluid through line 89 back to the tank 66 and 
the pump 64. 
When the control valve handle is moved from its neutral position at 88 to 
the position indicated at 90 in FIG. 4, the hydraulic fluid under pressure 
is delivered through line 91, seen also in FIG. 1, to the large chamber 52 
to cause extension of the piston rod 48. When the control valve handle is 
moved to the position indicated at 92 in FIG. 4, hydraulic fluid is 
delivered through line 93 to the small chamber 54 of the hydraulic 
actuator 12. Because of the large chamber 52, the piston 46 offers a large 
area so that for any given hydraulic pressure a substantial force is 
delivered to move the piston 46 and rod member 48 to the right as viewed 
in FIG. 1 so that the pad 56 moves a log disposed in its path against the 
blade assembly 14. 
The blade assembly 14 is effective to initiate a split in a log and soon 
thereafter the wings 32 of the spreader, which diverge at a greater angle 
than the teeth 34, are effective to rapidly separate opposite sides of the 
log and complete the split in a relatively short distance. This makes it 
possible to have a hydraulic actuator with a relatively short stroke so 
that the overall length of the log splitter 10 is maintained at a minimum 
to facilitate transport and storage. 
After the split of a log is completed, the handle of the control valve 86 
is moved through the neutral position indicated at 88 to the position 
indicated at 92 in FIG. 4 to cause delivery of hydraulic fluid to the 
small chamber 54. The small chamber 54 has less than one half the volume 
of the chamber 52 and as a result, a given amount of hydraulic fluid 
delivered to the small chamber will cause the rod member 48 to be 
retracted at a much greater speed than the rod 48 is extended during the 
splitting operation. This makes it possible to complete a full cycle of 
the splitting operation in a short period of time. 
During the splitting operation the chain saw power plant 84 is operated in 
the usual fashion, typically with a trigger type throttle control (not 
shown), and so long as the valve 86 is in one of its open positions and 
the engine is operating, hydraulic fluid is delivered to the actuator 12. 
To interrupt the splitting operation, the operator releases the throttle 
trigger and this interrupts the delivery of hydraulic fluid and stops the 
splitting operation and affords a safety advantage. 
The log splitter 10 can be built in a variety of sizes and particularly in 
larger sizes, it is advantageous to be able to dismantle the assembly. For 
example, the tube 18 of the base member 16 may be separated from the tube 
20 and the chain saw motor 84 may be removed from the drive bar 80 
offering three separate components which may be loaded into a vehicle for 
transport much more easily than when the parts are completely assembled 
together. Also, since the log splitter 10 does not require wheels for 
transport as is common with the trailer type of log splitters, the 
transport vehicle becomes available to tow a cargo trailer for hauling the 
split wood. 
Although the pump 64 together with the drive bar 80 and chain saw power 
plant 84 are illustrated as mounted above and on the remainder of the log 
splitter 10, it is contemplated that the pump assembly 64 with the chain 
saw motor 84 can be mounted on a separate base member and connected to the 
hydraulic cylinder by flexible conduits. 
Referring now to FIGS. 6 and 7 another embodiment of the invention is shown 
in which a log splitter 100 has a base 102 made of a single unitary I-beam 
rather than of two parts as in the prior embodiment. In this instance the 
pad 104 at the end of the piston rod 48 is guided by angle members 106 
which engage the upper flange 108 of the I-beam base member 102. Also, as 
seen in FIG. 6 a blade assembly 114 includes a cutting blade 116 having 
diverging splitting faces 118 and diverging spreader wings 120. As in the 
prior embodiment the wings 120 diverge at a greater angle than the cutting 
faces 118 of the blade to spread the log after the split in the log has 
been initiated so that opposed parts of the log are rapidly moved apart in 
a minimum distance of travel of the piston rod 48. 
In all other respects the embodiment shown in FIGS. 6 and 7 is the same as 
the prior embodiment using the engine 84 of a chain saw and an identical 
chain drive for a hydraulic pump which delivers hydraulic fluid to the 
hydraulic actuator 12. As in the prior embodiment transport and storage of 
the log splitter is facilitated by the ability to remove the engine 84. 
The log splitter has been provided in which both of the disclosed 
embodiments of the invention are highly portable and include a base member 
with a blade for penetrating one end of a log and a hydraulic actuator 
which forces the log against the splitting blade. The hydraulic fluid 
pressure for operating the actuator is supplied by a pump driven by a 
chain saw power plant wherein the cutting chain and guide bar of the chain 
saw are removed and the power plant is provided with a drive chain and a 
sprocket connected to a hydraulic pump. During operation one hand of the 
operator is used to control the chain saw power plant and the other hand 
is used to control a three position valve determining the extension and 
retraction of the rod of the hydraulic actuator forcing a log against the 
splitting blade.