Cutlery – Cutting tools – With support or attaching means
Patent
1983-12-02
1986-03-11
Peters, Jimmy C.
Cutlery
Cutting tools
With support or attaching means
30166R, 244 4A, B27B 1700, A01M 2100
Patent
active
045744815
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a motor assembly portable on the back which puts a substantially reduced load on the operator compared to conventional assemblies carried on the back. The novel motor assembly of the invention may advantageously be used for driving shearing and cutting tools in, for example, forestry and gardening, but may also be used for other purposes for which backcarried motor assemblies are or may be used.
In forestry motor assemblies carried on the back are used inter alia in sawing equipment for clearance work. A conventional clearing saw consists of an elongate supporting member, usually a power transmission tube, which at one end thereof supports an internal combustion engine and a saw blade at the other end. The clearing saw is supported in a harness attached to the rear portion of the supporting member to hang on one side of the carrier with the driving motor behind the carrier, and is operated via handle bars on the supporting member which are fixed in front of the point of attachment of the harness. Tools for bush pruning and the like are constructed in a corresponding manner. In addition to the fact that such a tool is relatively heavy in itself (a modern clearing saw weighs about 10-12 kg), the carrier is, despite specially constructed harnesses, subjected to a considerably biased load caused by the tool hanging on one side of the carrier. Since the driving motor, which is mounted to one end of the supporting member, also is considerably heavier than the cutting tool at the opposite end, the operator must counteract non-insignificant forces of inertia when swinging the tool sideways. Such twisting loads to the back are particularly harmful and additionally prevent a quick and accurate operation of the tool which reduces the safety. Another disadvantage of this type of motor driven tools is the fact that they are normally balanced with their center of gravity located somewhat before their connection to the harness, which forces the operator to continuously lift the fore supporting member with the cutting tool, which is tiring to the arms. Naturally, such an apparatus is very trying to work with and reduces the working capacity. Through the uneven load or bias the risk of industrial injuries is also high on a long view. There is therefore a need of a back-portable motor assembly for clearing saws and the like which puts a reduced load on the body and thereby will be easier to operate. Attempts have been made to achieve this, on one hand, by reducing the weight of the tool and primarily the weight of the driving motor itself which is heaviest part, and, on the other hand, by redistributing and balancing the tool load between the arms and the back in various ways. So far, however, no satisfactory, practicable construction has been produced. This would mainly be due to the necessary power output setting a lower limit to the weight of the driving motor. A result of the efforts to reduce the motor weight has been that the cooling fan system of the motor has become undersized for operation in intense heat.
The object of the present invention is to provide a motor assembly carried on the back which, despite having a driving motor, preferably an internal combustion engine, of at least the same power as the hitherto used motors, puts a substantially reduced weight load on the carrier and does not subject the latter to any bias. Applied to, for example, an equipment for a clearing saw or the like the motor assembly of the invention provides an easily operable and safe tool which also lacks the other disadvantages of the known and hitherto used sawing equipments.
The invention is based upon the concept that a part of the motor assembly power is utilized for "lifting itself", thereby reducing the weight to be carried. This is accomplished by making the motor assembly, simultaneously with driving the desired implement or tool, drive at least one propeller means in the form of a propeller, an impeller or the like, to provide a lifting force counteracting the weight of the assembly and suffi
REFERENCES:
patent: 2461347 (1949-02-01), Pentecost
patent: 2909068 (1959-10-01), Haug
patent: 3023980 (1962-03-01), Martin et al.
patent: 3040471 (1962-06-01), Blase
patent: 3219129 (1965-11-01), Yamada
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