1993-06-11
1995-01-24
Bray, W. Donald
Cutlery
Powered planer
30477, 144117C, 144252R, 409137, 409295, B27C 110
Patent
active
053832752
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a hand planer.
More particularly, it relates to a hand planer having a housing supporting a planer head rotatable by a motor, a fan blower connected with the motor for generating a flow of air for moving chips, a chip ejector to which the flow of air is guided via air guidance ducts, and a chip conveying duct through the planer chips exit.
A hand planer of the generic type is known from DE-OS 34 06 728. In this hand planer the chips are discharged from a chip discharge opening of a chip conveying duct by the pumping and sucking action of one or two streams of cooling air to two chip ejecting openings which can be opened alternately in an optional manner. The chip ejecting opening can be unblocked toward one side or the other transversely to the feed direction by a swivelable, flap-type valve. This hand planer has the disadvantage that the removal of chips via the cooling air flow at or in the chip conveying duct proceeds with inadequate efficiency, i.e. an excessive air flow rate is required for a small quantity of chips.
The known hand planer is described in two embodiment examples. In the embodiment example with only one cooling air flow, the conveying effect is fully effective only in a preferred direction, namely when the cooling air can flow substantially parallel to the flap-like valve toward the ejecting opening.
However, if the ejecting opening directed opposite to the preferred direction is preselected rather than the preferred direction, the cooling air flow rebounds off the flap-like valve virtually normally thereto and the velocity of the air flow, and accordingly the conveying effect, is reduced as a result of turbulence. The chip conveying duct can become stopped in this way.
In the embodiment example with two cooling air flows acting simultaneously at both sides of the chip discharge opening, the conveying effect is improved, but the turbulence is also increased in the region of the valve. Accordingly, the efficiency with which the chips are moved is still definitely reduced. This makes poor use of the available conveying capacity.
Further disadvantages of the hand planer include the relatively poor sealing effect of the valve and a constant, unintentional escape of chips from the ejecting opening which is closed per se, as well as the poor possibility of distinguishing the selected chip ejecting direction and the trouble-prone character of the expensively constructed valve bearing.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a hand planer of the above mentioned general type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a hand planer, in which means are provided for guiding the entire flow of air in a switchable manner to the chip conveying duct via one of the two air guidance ducts.
When the hand planer is designed in accordance with the present invention, it has the advantage over the prior art that the chips are carried off in every ejecting direction with the same high quality. Moreover, the valve of the switching means is sealed particularly well so that each ejecting direction is determined in a definite manner and no chips can be ejected or interference by sawdust caused in an unintended direction. The selected ejecting direction can be distinguished particularly well at the valve and the adjustment of the valve is extremely simple. Moreover, the valve is constructed in a robust manner and is simple to produce. Disturbances are practically eliminated.
Further advantageous constructions of the invention follow from the dependent claims. The chips are carried off equally well in both ejecting directions, in both cases better than is known in the prior art, because the air guidance duct producing the most effective ejecting and suction pumping effect by blowing over the chip discharge opening is always opened.
The novel featur
REFERENCES:
patent: 4601104 (1986-07-01), Zaiser et al.
patent: 5007469 (1991-04-01), Englert et al.
patent: 5034041 (1991-07-01), Austin
patent: 5094000 (1992-03-01), Becht et al.
Floettmann Kai-Uwe
Hild Eugen
Bray W. Donald
Robert & Bosch GmbH
Striker Michael J.
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