Attachment for a surveyor's instrument

An attachment triggers dispensation of paint through the valve of an inverted aerosol can onto a surface target in response to manipulation of a surveyor's rod or pole. A coupling connects the attachment to the lower end of the surveyor's instrument and a cap seals against the valve end of the inverted aerosol can. A support structure holds the coupling, the inverted aerosol can and the cap together for motion in unison. A nozzle defines a path of pneumatic communication from the valve through the cap. The portion of the cap surrounding the nozzle is resiliently pliable so that, when the nozzle is rested on and the surveyor's instrument is pressed toward the surface target, the resiliently pliable portion of the cap flexes to actuate the valve and dispense paint through the nozzle onto the surface target.

BACKGROUND OF THE INVENTION

This invention relates generally to surveying equipment and more particularly concerns a target marking attachment for a surveyor's line rod, prism pole, GPS system rover rod or the like.

In present practice, surveying partners determine a target point by shooting a line and distance using surveyors' instruments and making a hole in the surface at the correct target point. Because it is difficult to make a hole precisely at the correctly determined target point, multiple shootings are generally necessary before the surveyors are satisfied with the accuracy of a hole. Subsequently, the surveyors drive a nail or piece of rebar into the selected hole to monument the point. This process is time consuming, not only because it is repetitious, but because it requires the use of separate instruments and tools to shoot, mark and monument points. Moreover, depending on the nature of the surface to be marked, driving the nails or rebar can be a laborious task.

It is, therefore, an object of this invention to provide an attachment for a surveyor's instrument which facilitates marking of a correct target point. Another object of this invention is to provide an attachment for a surveyor's instrument which facilitates precise marking of a correct target point. A further object of this invention is to provide an attachment for a surveyor's instrument which enables marking a target point without removing the surveyor's instrument from the target point. Yet another object of this invention is to provide an attachment for a surveyor's instrument which reduces the need for shooting multiple target points in order to achieve an accurate target point. It is also an object of this invention to provide an attachment for a surveyor's instrument which eliminates the need for nails, rebar and special tools to monument a target point. Still another object of this invention is to provide an attachment for a surveyor's instrument which eliminates the expenditure of time and labor to monument a target point.

SUMMARY OF THE INVENTION

In accordance with the invention, an attachment is provided for triggering dispensation of paint through the valve of an inverted aerosol can onto a surface target in response to manipulation of a surveyor's instrument, such as a line rod, a prism pole or a GPS system rover rod. The attachment has a coupling adapted to connect to the lower end of the surveyor's instrument and a cap adapted to seal against the valve end of the inverted aerosol can. A support structure holds the coupling, the inverted aerosol can and the cap together for motion in unison. A nozzle defines a path of pneumatic communication from the valve through the cap. The portion of the cap surrounding the nozzle is resiliently pliable so that, when the nozzle is rested on and the surveyor's instrument is pressed toward the surface target, the resiliently pliable portion of the cap flexes to actuate the valve and dispense paint through the nozzle onto the surface target.

Preferably, the coupling, cap and support structure co-operate to align the surveyor's tool, the valve of the aerosol can and the nozzle on a common axis so as to focus the force applied to the instrument directly at the target surface. The coupling and support structure are sufficiently rigid to resist distortion when the resiliently pliable portion of the cap is flexed.

Preferably, the nozzle has an upper throat which tapers upwardly and outwardly to form a seat to guide the valve of the aerosol can into engagement against the nozzle. A middle throat tapers downwardly and outwardly from the lower end of the upper throat to expand the nozzle. A lower throat extends cylindrically downwardly from the lower end of the middle throat to the target end of the nozzle. A cylindrical throat of approximately one inch inside diameter defines a target surface of acceptable tolerance. At least one vent hole through the cylindrical throat side wall reduces the possibility of clogging the nozzle during repeated use.

Preferably, the cap is adapted to seal against the rim of the valve end of the aerosol can and the upper throat of the nozzle extends upwardly from the cap and is aligned and contoured to seat the valve of the aerosol can when the cap is sealed against the rim of the can.

Preferably, the support structure is a cylindrical container of height substantially equal to the height of the aerosol can. The upper end of the container is adapted for concentric connection to the lower end of the surveyor's instrument. The cap screws onto the lower end of the container and has a concentric resiliently pliable central portion with a concentric central aperture. The upper throat of the nozzle extends concentrically upwardly to the valve of the aerosol can and the middle and lower throats of the nozzle extend concentrically downwardly from the upper throat.

Preferably, the coupling includes an inside-threaded tube so as to easily engage on the lower end of the surveyor's instrument and to facilitate rapid transfer of the same attachment from one instrument to another and the cap screws onto the container to permit easy replacement of the aerosol can in the attachment.

In an alternative embodiment, rather than a resiliently pliable cap portion, the nozzle reciprocally slides in and extends through the cap and compression spring biases the can against motion toward the nozzle. When the surveyor's instrument is pressed downwardly the bias is overcome, activating the valve.

In any of the above embodiments, the coupling and cap are joined by an associated connecting structure. However, the connecting structure may be eliminated by securing the coupling and cap directly to the can, thus using the can as the connecting structure.

While the invention will be described in connection with a preferred embodiment thereof, it will be understood that it is not intended to limit the invention to that embodiment or to the details of the construction or arrangement of parts illustrated in the accompanying drawings.

DETAILED DESCRIPTION

Looking at the Figures, the target surface marking attachment for a surveyor's instrument has a coupling11, a cap13and a co-operable supporting structure15to hold this assembly together for movement in unison. As shown, the coupling11and the supporting structure15consist of the top17and the side walls19of a container21. The container21is contoured to hold a can23of aerosol paint in an inverted orientation. The height of the container21is substantially the same as the height of the can23. Thus, when the cap13covers the open bottom of the container21, the can23cannot slide axially in the container21.

The top17of the container21, as shown, has a central internally threaded tube25into which the lower end of the surveyor's instrument (not shown) can be threadedly engaged. The cap13, as shown, is threadedly engaged27to the bottom of the container21and has a peripheral interior flange29against which the rim of the can23is sealed. The interior portion31of the cap13is resiliently pliant. As shown, this may be accomplished by making the interior portion31of the cap13substantially thinner than the flange29. A nozzle33extends through the resiliently pliant portion31of the cap13. The upper portion35of the nozzle33is upwardly outwardly tapered to provide a seat37to guide the valve39of the can23into the nozzle33and to abut and support the nozzle33when the can23is sealed against the flange29of the cap13. The middle portion41of the nozzle33tapers downwardly and outwardly below the seat37to expand the nozzle33. Preferably, the nozzle33is expanded to an approximately 1 inch inner diameter. The lower portion43of the nozzle33extends cylindrically downwardly from the expanding middle portion41.

As shown, it is preferred that the coupling tube25, the valve39of the can23and the nozzle33are all concentrically aligned on a common axis45so that force applied to the instrument is aligned through the axial center of the nozzle33. The lower portion43of the nozzle33may have one or more vent holes47so that excess paint can be exhausted radially from the nozzle33to reduce the possibility of clogging the nozzle33. Other than the resiliently pliable portion31of the cap13, the components of the attachment are sufficiently rigid so as not to appreciably distort when force is applied to flex the resiliently pliable portion31. The attachment components may be made of any suitable material provided the inner portion31of the cap13is able to resiliently flex and the other components have sufficient resistance to distortion to allow the inner portion31to flex.

In operation, the aerosol paint can23is loaded in its inverted condition into the container21and the cap13is screwed in place until the cap flange29seals against the rim of the can23. In this condition, the valve39of the can23should be extending into and engaged against the seat37of the nozzle33. The attachment is secured to the lower end of the surveyor's instrument (not shown) by threading the lower end of the instrument into the threaded tube25on the top17of the container21. The surveyors can now use the surveying instrument (not shown) in the usual manner except that, rather than the lower end of the instrument being in contact with the surface49to be marked, the lower end of the nozzle33is rested on the surface49. When the target point has been accurately determined, the cylindrical portion43of the nozzle33will be surrounding the target surface51. The application of downward force by the surveyor on the surveying instrument (not shown) causes the side walls19of the container21to press downwardly on the peripheral flange29of the cap13. This, in turn, drives the seat37of the nozzle33upwardly against the valve39of the can23, causing the valve39to release paint into the nozzle33to coat the target surface51. The target surface51is thus marked without ever moving the nozzle33from the accurate position.

Turning toFIG. 3, an alternate embodiment of the target surface marking attachment is illustrated having a cap63which does not have a resiliently pliable portion. In this embodiment, the sidewalls65of the cap63extend considerably below threaded engagement67on the sidewalls19of the container21. The lower portion69of the cap63is conical and there is a central opening through which a nozzle71extends. A guide seat73in the conical section69of the cap63guides vertical reciprocation of the nozzle71. A flange75around the midportion of the nozzle71is seated on the guide seat73. A coil spring77around the upper portion of the nozzle71between the flange75and the can23biases the nozzle71against movement toward the valve39. The upper interior portion of the nozzle71tapers to the valve39and the valve39is seated on the inwardly tapered valve seat81of the nozzle71. The valve39is not actuated when the nozzle flange75merely rests on its seat73. However, when force is applied to the surveying instrument (not shown), the nozzle71is driven upwardly against the coil spring77to overcome the bias and actuate the valve39, dispensing paint from the can23into the nozzle71.

In variations of the above described attachments, the couplings11and the caps13and63could be separately attached by supporting structure directly to the top and bottom of the can23. In these configurations, the side walls19of the can23apply the downward forces from the coupling11to the caps13and63.

Thus, it is apparent that there has been provided, in accordance with the invention, a target surface marking attachment for a surveyor's instrument that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with a specific embodiment thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.