Refrigeration – Structural installation – With electrical component cooling
Reexamination Certificate
1999-10-07
2001-04-24
Doerrler, William (Department: 3744)
Refrigeration
Structural installation
With electrical component cooling
C062S434000
Reexamination Certificate
active
06220046
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to an equipment for working a hard material and includes a housing, a driving motor located within the housing, a tool connected to the driving motor and arranged to work the hard material, a cooling duct located within the housing in a region about the driving motor. A coolant supply source supplies coolant under pressure via a coolant supply pipeline to the coolant duct. After flow through the coolant duct, coolant passes into a coolant discharge pipeline.
To produce boreholes or openings in hard materials, drilling or cutting equipment is used including tools tipped with cutting segments formed of diamond particles. Such equipment must perform differently, depending on the hardness of the material or the depth of the borehole or cuts to be produced. Particularly in high-powered equipment, heat is developed in the drilling or cutting process in the region of the driving motor and in the region of the associated electronic components and can lead to interference with the control of the equipment. In the region of components for controlling the equipment, including at least one electronic component, high temperatures can be produced by heat accumulation, by surrounding high temperatures or by inadequate ventilation of the electronic component if it happens to be covered with dust, or its ventilation slots are closed off almost completely by dust accumulation, so that surrounding cooling air can no longer reach the electronic component.
To dissipate the heat developing in the region of a driving motor while working a hard material, drilling equipment with a drilling motor is disclosed in DE 43 30 520 in connection with a drilling tool, a part of the housing, surrounding the driving motor, being traversed by a cooling duct running spirally from an inlet, located opposite the drilling direction, over the entire driving motor to an outlet on the drilling side. A coolant is passed through the cooling duct under pressure from an external coolant supply source and is supplied to the inlet by a coolant supply pipeline. A coolant discharge pipeline extends from the outlet from the cooling duct to the drilling tool. Aside from cooling the drilling tool, the coolant supplied through the coolant discharge pipeline to the drilling tool also serves to flush drillings out of the drilled borehole and in certain applications, coolant must be prevented from reaching the drilling tool. In such a case, the coolant discharge pipeline connects the cooling duct outlet with the coolant supply source.
In the drilling equipment disclosed in the DE 43 30 520, only the driving motor is cooled with coolant. In the region of the electronic components, however, which controls the driving motor, heat can increase greatly and lead to interference with the control of the drilling equipment.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide equipment for working hard material, even when a high load is imposed on the equipment, when the surrounding temperature is high and when the surroundings are extremely dusty for affording optimum cooling for the electronic components involved.
In accordance with the present invention the equipment is distinguished in that the pipeline supplying the coolant flows through a cooling device which effects cooling of at least one electronic component.
Since the cooling device interacting with the electronic component is located in the pipeline supplying the coolant, the coolant under pressure flows from the coolant supply source first through the cooling device and subsequently through the cooling duct for the driving motor. Preferably, the cooling device is formed of at least one basic member having good thermal conductivity properties and on which the electronic component is positioned. The basic member is formed of aluminum, it has a continuous duct through which the coolant flows and, at the same time, dissipates heat generated by the electronic component or which is developed by the atmosphere surrounding the basic member.
To provide equipment capable of easy handling, preferably the cooling device is positioned in the equipment housing. The cooling device is connected with the cooling duct of the driving motor by the coolant supplied pipeline.
To determine if the coolant is circulating or flowing throughout the cooling system, composed essentially of the coolant supply source, the coolant supply pipeline, the cooling device, the cooling duct and a coolant discharge passageway, preferably the cooling device works in combination with a flow monitor.
Since the electronic component is sensitive to high temperatures, it must be insured that the coolant flows through a basic member connected with the electronic component before the driving motor controlled by the electronic component is started up whereby, as a result, initially the electronic component is strongly heated. Accordingly, the flow monitor interacts with the electronic component. As an example, the flow monitor is a magnetic switch, which can be operated by the circulating coolant under pressure, against force of a spring, and in an end position the magnetic switch, by means of a signal, informs the electronic component of the coolant circulation in the coolant system. When such signal reaches the electronic component, the driving motor can be started up. The absence of the signal to the magnetic switch indicates that the coolant is not circulating in the cooling system and the cooling device is not being cooled.
To prevent coolant draining from the cooling duct of the driving motor, when the equipment is not in operation, the cooling device advantageously interacts with a shut-off valve, so that the supply of coolant to the driving motor can be controlled.
For selectively directing the coolant, passing through the coolant discharge pipeline, a reversible distributor is provided so that the coolant can be supplied either to the drilling tool or to the coolant supply source. From the reversible distributor the coolant can take separate branches of the coolant discharge pipeline, one branch being connected to the tool and the other to the coolant supply source.
A portion of the coolant can be directed to the tool and another portion to the coolant supply source with the two portions each preferably being fifty percent of the coolant, so that the reversible distributor preferably has three switching positions. In a first switching position, all of the coolant is directed over a first branch to the tool, in a second branch all of the coolant is supplied to a coolant supply source and, in a third switching position, the cooling is supplied both to the tool and to the cooling supply source.
If the equipment is used at a site where fresh water, serving as coolant, is not available from a local water supply system, advantageously the coolant supply source is formed by coolant processing equipment made up of a coolant tank, a device for cooling, cleaning and/or filtering the coolant and a pump, so that the coolant can be directed under pressure to the cooling duct.
For easy handling of the equipment by the operator, the coolant processing equipment is preferably disposed in spaced relation to the housing.
The invention will now be explained in greater detail with the reference to the drawings, showing an embodiment example of the invention. In the drawing:
REFERENCES:
patent: 4095916 (1978-06-01), Hammond
patent: 4676319 (1987-06-01), Cuthbertson
patent: 5474120 (1995-12-01), Severson et al.
patent: 5951217 (1999-09-01), Ostermeier et al.
patent: 6113320 (2000-09-01), Ostermeier et al.
Bongers-Ambrosius Hans-Werner
Kristen Ferdinand
Reisinger Erwin
Schitti Josef
Brown & Wood LLP
Doerrler William
Hilti Aktiengesellschaft
Jones Melvin
LandOfFree
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