Drill level indicator

A power tool includes a leveling device which includes a rotatable member which seeks an equilibrium position which corresponds to a level position. A rotating device includes a member which enables passage of a beam. An electrical circuit which includes an emitting device, a receiving device and an indicating device is electrically coupled such that upon activation, the emitting device emits a beam which passes through the beam passing member. The beam is received by the receiving device which, in turn, activates the indicator device. The indicator is generally a light emitting device which has a varying brightness so that the user may view the indicator from all sides of the power tool.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to power tools and, more particularly, to a leveling device that indicates when the power tool is in a level position.

In various types of power tools, especially drilling tools, it is desirable to know when the tool is in a horizontal or vertical plane. This is particularly useful when drilling holes for hanging doors or the like when it is desirable to have holes which are in plane with horizontal.

Bubble types of levels have been utilized in power tools. However, these types of leveling devices have various shortcomings. While the bubble level works satisfactorily for horizontal applications, it is still burdensome on the user to view the bubble in between the lines. Ordinarily, these bubble types of levels are not conducive for vertical drilling. Also, due to the vibration of the tool, frothing occurs inside the level, rendering the bubble level useless in many applications.

Another type of measuring device utilizes a simple pendulum with a rigid straight bar connecting the pivot point with a hanging weight together with a cross bar mounted at ninety (90°) degrees to a vertical bar. The cross bar can be disposed on either side of the pivot point when the pivot level is hung and the weight achieves equilibrium, the cross bar will be positioned in a horizontal plane. Accordingly, the ends may be aligned with two notches on a carrier board to align the board to the horizontal and thus measure the horizontal plane.

Both of these devices require the user to have an accurate view of the level during drilling to maintain the plane of the power tool. Also, while these types of devices may be satisfactory in horizontal drilling planes, they are not particularly useful when used in a vertical drilling arrangement.

Accordingly, it is an object of the present invention to provide a user with an easy to use leveling device. The device indicates to the user, usually by an illuminated light, that horizontal or vertical planes have been achieved. The present invention enables the user to readily establish visual contact to indicate that a desired level position has been achieved.

SUMMARY OF THE INVENTION

In accordance with a first embodiment of the present invention, a power tool leveling device comprises a housing with a cavity in the housing. A rotating member is positioned in the housing. The rotating member moves in the cavity such that the rotating member seeks an equilibrium position. The equilibrium position corresponds to a level position. At least one member is associated with the rotating member to enable passage of light through the rotating member. An electrical circuit is associated with the rotating member. The electrical circuit includes an emitting device, a receiving device, and an indicator device. These devices are electrically coupled such that upon activation, the emitting device emits a beam which passes through the at least one member. The beam is received by the receiving device which, in turn, activates the indicator device. The indicator device informs a user that the leveling device is in an equilibrium position. Also, a power source is coupled with the electrical circuit to energize the electrical circuit. The electrical circuit further includes a device for varying current to the indicator device such that as the beam intensity at the receiver device increases, the indicator device increases in intensity. This corresponds to leveling; e.g., as the tool becomes more level, the intensity increases. The device for varying the current is a PNP transistor. The indicator device is a light emitting device. The light emitting device has a variable intensity from off to full on. In the full on position the leveling device is in its level position. The at least one member in the rotating member is an aperture. In an alternate embodiment, the aperture includes a lens for refracting the beam. In a second alternate embodiment, a lens is positioned between the rotating member and the receiving device to refract the beam. Also, the at least one aperture may be an elongated slot. Further, the at least one member may be an optic fiber to transmit the beam. Also, a switch is coupled with the leveling device for activating and deactivating the electrical circuit.

In accordance with a second aspect of the invention, a power tool comprises a housing with a motor in the housing. An output is coupled with the motor. An activation member to energize the motor for rotating the output is coupled with the motor. A power source is electrically coupled with the motor and activation member. A leveling device is present in the housing. The leveling device comprises a housing with a cavity in the housing. A rotating member is positioned in the housing. The rotating member moves in the cavity such that the rotating member seeks an equilibrium position. The equilibrium position corresponds to a level position. At least one member is associated with the rotating member to enable passage of light through the rotating member. An electrical circuit is associated with the rotating member. The electrical circuit includes an emitting device, a receiving device, and an indicator device. These devices are electrically coupled such that upon activation, the emitting device emits a beam which passes through the at least one member. The beam is received by the receiving device which, in turn, activates the indicator device. The indicator device informs a user that the leveling device is in an equilibrium position. Also, a power source is coupled with the electrical circuit to energize the electrical circuit. The electrical circuit further includes a device for varying current to the indicator device such that as the beam intensity at the receiver device increases, the indicator device increases in intensity. This corresponds to leveling; e.g., as the tool becomes more level, the intensity increases. The device for varying the current is a PNP transistor. The indicator device is a light emitting device. The light emitting device has a variable intensity from off to full on. In the full on position the leveling device is in its level position. The at least one member in the rotating member is an aperture. In an alternate embodiment, the aperture includes a lens for refracting the beam. In a second alternate embodiment, a lens is positioned between the rotating member and the receiving device to refract the beam. Also, the at least one aperture may be an elongated slot. Further, the at least one member may be an optic fiber to transmit the beam. Also, a switch is coupled with the leveling device for activating and deactivating the electrical circuit.

In accordance with a third aspect of the invention, a power tool comprises a housing with a motor within the housing. An output is coupled with the motor. An activation member energizes the motor to rotate the output which is coupled with an output source and the motor. A leveling device is coupled with the power tool. The leveling device includes an indicator such that upon activation of the leveling device the indicator indicates to a user that the leveling device is in an equilibrium position. The leveling device is also coupled with the power source. The indicator is positioned on the housing such that a user may view the indicator from all sides of the housing when the power tool is in use. The indicator varies in intensity as the leveling position is reached. The indicator is ordinarily a light emitting device. Accordingly, the light emitting device varies in brightness, being brightest when the power tool is in the level position. Also, a switch is coupled with the activation member for activating the leveling device prior to activating the motor.

From the following detailed description, taken in conjunction with the drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning to the figures,FIG. 1illustrates a power tool in accordance with the present invention and is designated with the reference numeral10. The power tool10is illustrated as a drill; however, any type of power tool such as a screwdriver, sander, rotary tool, clippers, hedge trimmer, saw or the like may be utilized with the level indicator in accordance with the present invention. The power tool10includes a housing12which includes two halves14which surround a motor18. An activation member20is coupled with the motor as well as with a power source22. The power source22may be a power cord (AC current) or the power tool may have a battery (DC current) as shown. The motor18is coupled with an output24which may include a transmission26and a chuck28to retain the tool with the drill.

A level indicator30is positioned in the housing half14. The level indicator30includes a housing32and circuitry34. Turning toFIG. 3, the level indicator housing32includes two halves36and38which are secured together, preferably by a snap fit. A rotatable member40is rotatably positioned within the housing half36. The rotatable member40has an overall disc shape with an axle42extending through the center of the rotatable member40, and with the axle ends in blocks43. Also, apertures44, preferably four in number, are formed in the disc40. Also, a counter-weight46is coupled with the rotating member40.

The rotatable member40rotates within a cavity48in the housing halves36and38about the axle42. The counter-weight46provides a weighted side of the rotatable member40so that the rotatable member40is always seeking an equilibrium position. The apertures44are positioned about the rotatable member40at zero (0°) degrees, ninety (90°) degrees, one hundred eighty (180°) degrees, and two hundred seventy (270°) degrees about a three hundred sixty (360°) degree circle of the rotating member40. The apertures44have a desired size, preferably with a diameter of 0.5 mm. which enables sensing as will be described herein. The rotatable member40rotates throughout three hundred sixty (360°) degrees within the housing32as the power tool is manipulated.

Circuitry34is best defined inFIG. 4. Broadly speaking, the circuitry includes a light emitter50, a light receiver52and an indicator54. Lead56extends from the power source22to switch58. Lead60leads from the switch58to the emitter50. Also, a resistor R1is electrically coupled in lead60. R1may have a value as illustrated in Chart1below, varying with the voltage of the power source. Lead60is coupled with lead64which electrically couples the switch with the receiver52. Lead64extends from lead60to the receiver52. A pair of resistors R2and R3are electrically coupled in lead64extending to the receiver52. Lead60is electrically coupled with lead66. Lead66is electrically coupled with the indicator54. Transistor Q1is electrically coupled in lead66. Transistor Q1is a PNP transistor. Thus, a base lead68is coupled with lead64between resistors R2and R3. A fourth resistor R4is coupled with lead66between the transistor Q1and the indicator54. Further, lead70is coupled with the power source22, leads62,64and66.

The emitter50is preferably an infrared emitter generating a stream of light towards the receiver52. Preferably, the emitter50is axially positioned 2:1 mm. away from the rotatable member40. The receiver52is preferably a phototransistor to receive the light generated from the infrared LED50. Preferably, the phototransistor52is axially positioned 1.5 mm. away from the rotatable member40. The indicator54is preferably an LED having a desired color such as red.

The leveling device30operates as follows. The trigger17of the activation member20is pushed inward to contact switch58. As this occurs, the circuit is activated. However, the switch58is activated before the motor14. Upon activation of the switch58, the circuit is closed so that current moves through the lead60. As current moves through the lead60, current passes to the emitter50turning on the emitter50generating a light beam72. If the rotatable member40is in a non-level or non-equilibrium position, the apertures44do not align with the beam72and therefore light does not pass across the rotatable member40and light is not sensed by the receiver52. In this case, the indicator54does not illuminate. This is due to the fact that the current at lead68is blocked and therefore the transistor Q1does not allow current to pass to the indicator LED54.

Once the leveling device approaches an equilibrium or level position so that the power tool is on or near a horizontal or vertical plane, one of the apertures44is in alignment with the beam72from the infrared LED50. As this occurs, the beam72passes through the rotatable member40. The beam72is sensed by the phototransistor receiver52. As this occurs, the receiver phototransistor52is energized. As this occurs, current passes from lead60through lead64to lead70completing that circuit. As this happens, the current in base lead68is conductive. As the transducer Q1senses the change in current between the emitter and base, current begins to flow from the collector to the emitter along lead66. As this occurs, current flows to indicator LED54illuminating the indicator54.

Since small apertures44are used which may have a conical shape, the beam intensity increases through the rotatable member40, as the rotatable member40becomes more level and the apertures44are centered and directly in line with the beam72. As this occurs, the receiver phototransistor52senses a higher intensity in the beam72. Thus, more current passes through the phototransistor52. As this occurs, the current sensed by the base of the transistor Q1increases in lead68. As this occurs, the transistor Q1senses an increase in base current of the PNP transistor. As this occurs, the PNP transistor Q1enables more current to pass through it which, in turn, increases the intensity of the illumination of the indicator54. Thus, a variable output is established. The indicator54varies in intensity from off to its brightest point when the leveling device is in its most level position.

A plus or minus six (6°) degree range from level is present where the light goes on. When the tool is further than six (6°) degrees away from level, the light is in an off position. When the power tool comes within the six (6°) degrees of level range, the light begins to turn on. As the light hits the level position, the light at its brightest. As it approaches the other side of the six (6°) degrees (positive or negative), the light would again go off. Thus, the user can determine if he is high or low of the level position when the light is the brightest.

A chart is provided below which provides the values of R1, R2, R3and R4in the above circuit diagram. Note that the values of R1and R4vary depending upon the voltage of the power source.

The indicator LED54is positioned between the housings at a top rear position of the tool. When the tool is used by a user, the user ordinarily is positioned behind the tool. Also, as illustrated inFIGS. 1 and 1a, the indicator LED is ordinarily positioned above the contour of the housing so that the LED can be viewed by the user from all sides and angles of use of the drill. Thus, the user can readily view whether or not the light is illuminated and the power tool is level.

As can be seen inFIG. 1, the activation member20includes trigger80for activating the motor. The trigger80includes a plunger shaft82as well as a leaf contact actuator84. The leaf contact actuator84contacts the micro-switch58for activating the leveling circuit. The leaf contact actuator84contacts the leaf contact86which pushes down the plunger88actuating the switch58.

Turning toFIG. 5, a second embodiment of the leveling device is shown. Here, the leveling device is substantially similar to that as previously described. The difference is that lenses90are positioned in apertures44to enhance the refractiveness of the beam72.

Turning toFIG. 6, an additional embodiment is shown. Here, the embodiment is the same as previously described. However, a lens92is positioned between the rotative member40and the receiver52to enhance the beam passing through the apertures44.

Turning toFIG. 7, an additional embodiment is shown.FIG. 7illustrates a rotatable member40′. Here, the apertures44′ have an elongated shape enhancing the variable output of the indicator54.

Turning toFIG. 8, an additional embodiment is shown. InFIG. 8, optic fibers96and98are positioned in rotatable member40′. The optical members extend like spokes across the rotating member40. Also, the emitter50and receiver52are positioned radially with respect to the rotatable member.

While the above detailed description describes the preferred embodiment of the present invention, the invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims.