US2493946A - Gradometer - Google Patents

Description

Jan. 10, 1950 G, CRAFT ET AL 2,493,946

GRADOMETER Filed Dec. 18, 1947 IN V EN TORS V6. Car/son Glen Craft Patented Jan. 10, 195( OFFICE GE BOMEFBE 1 n waters (lulfignnQherpkee, 1

-m be 1 47,. 'Serial'No;792;564 @Ql ims- (01. 33

This invention melates to improvements in gradometers, and has for its principal object the provision of a device adapted for attachment ito a vehicle such as a tractor in view of the driver to provide a guide dor maintaining :contour lines in farming operations.

A general object of the invention is to provide a device which willenable a farmer to determine the slope of a field and make any necessary contour adjustment :as he gplpws whereby to avoid the tedious and time consuming, method heretofore employed of walking over the field with .a hand level and staking out contour lines preparatory to subsequent plowing.

A further and more specific object of the inventionis to provide a gradometer of ruggedzanii durable construction .to withstand usage on a farm tractor .but capable of constantly accurate slope measurement .during :and after #long pcriods .of such usage.

Another object is to proyide a gradometer pendulum and indicator construction having the parts thereof shielded against breakage ordamage from contact with .other objects and ,protected against injury and maladjustment which might ordinarily result from extremes of abrupt movement.

Other and further objects and advantages of the invention will be apparent from the "following detailed description taken in conjunction with the accompanying drawings wherein a preferred embodiment of the principles of the invention has been selected for exemplification.

In the drawings:

Fig. 1 is a front elevational view of a gradometer constructed in accordance with the invention; I

Fig. 2 is a central vertical sectional view of the device shown in Fig. 1;

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 2; and

Fig. 4 is a perspective view looking downwardly at the rear of the device with the cover removed to show the pendulum support and cam construction.

Referring more particularly to the drawings,

wherein like numerals refer to like parts, a housing is provided having side walls In and a bottom wall l2 which preferably is arcuate substantially to parallel the path of the swinging pendulum bob, as shown. The housing is adapted to contain a body of fluid, for example, an oil of uniform viscosity at various extremes of temperature, to damp and cushion the movement of the pendulum. A cover [4 prevents spillage of the ,2 fluid and protects the operating parts positioned within the housing.

A gravity a-pendulum :bob 1:6 is secured to the lower .portion .of )3 rigid arm [8, the longitudinal edges of which .are -laterally .bent and apertured at their upper portion .to receive a horizontal shaft 20 which is fixed transverselylof the housing to provide a pivotal support for the pendulum. To prevent arm l8 from sliding axially of the shaft 2 0 :collars 52z| are :disposed between :the bent edges :of the arm and :adjacent side walls of the housing.

The farm 21.6 is relatively wide, extending a :sub stantialapart of the width of the 1housing, as that its etc :and fro .swing will be resisted to .a certain degree by the liquid within the housing. Such resistance may be controlled and the weight of arm 1:8 decreased by the provision of apertures, ashhewnxinf'igfi. Further to restrict the swing ofathe pendulum arm i8 and functioning also to reduce friction :by relieving the weight of the pendulum ion journal shaft .26, a tension spring 22 is interposed between the upper end of arm l8 and the adjacent wall portion 24 of the housing.

a The wall portion .24, as .shown, is flared and adaiits upper .edge calibrations graduating outwardly medially :of its :ends. Vertically positioned pointer 26 is adapted to register with such calibrations and is protected by a guard plate 28 offset outwardly of and carried by the wall 24.

The laterally bent lower end of pointer 26 projects through the adjacent wall of the housing and is secured to a collar 39. Adjustably fixed in collar 30 by means of a set screw 32 is one end of a shaft 34, the other end of which is journalled in a bracket 36 carried by the housing wall. Shaft 34 extends axially of the laterally bent end of pointer 26 to which it is secured and as the shaft 34 tends to rotate the pointer 26 will be moved in a corresponding direction, the extent of such movement being registered on the calibrated dial. To translate forward and rearward tilting of the housing on a horizontal axis to movement of the pointer 26 in an upright plane, a cam 38, which may conveniently be carried by an ear 4!] struck of the pendulum arm I 8, engages an elongated cam follower 42 fixed to the shaft 34. Thus, forward tilting of the housing, as when the vehicle to which it is attached faces downhill Will elevate cam 38 and, as the cam rides in the cam follower 42, the shaft 34 will tend to rotate in a counterclockwise direction and move pointer 26 along the down side of the calibrated dial. Conversely, rearward tilting of the housing as when the vehicle faces uphill,

3 will lower cam 38 and, as the cam rides in cam follower 42, the shaft 34 will tend to rotate in a clockwise direction and move the pointer 26 along the up side of the dial. The extent of the grade will, of course, be registered on the dial for the guidance of the vehicle operator.

In operation, as in contour plowing, the device above described is mounted upon the dashboard or steering column or engine hood of a tractor or other vehicle in a manner to be readily visible to the operator and the pointer 26 is set at the level or zero point of the dial by adjusting the relative positions of the shaft 34 and collar 39- by means of the set screw 32. As the tractor proceeds, the device will reflect the percent of slope above or below the level or contour line so that the operator may readily correct the position of the plow whenever the pointer moves from 2. A gradometer comprising, an upright housing supporting a calibrated dial at its upper portion and having a lower portion adopted to contain a body of damping fluid, a pendulum arm carrying a pendulum bob disposed in said body of damping fluid, said pendulum arm being of paddle-like form whereby to present a relatively broad surface area to the damping fluid in the direction of its path of movement, a shaft extending transversely of saidhousing on a fixed axis to provide a bearing support for said pendulum arm, means for supporting said pendulum arm intermediate its height on said shaft, spring means depending from the upper portion of said housing and connected to the upper end of that portion of said pendulum arm which extends above said shaft to. relieve the bearing weight of the zero point. Thus, a field may be surveyed as it is plowed and the tedious system heretofore used. of walking out contour lines to guide the tractor may be avoided.

It will be understood that the device herein described and illustrated is exemplary only of the principles of the invention which embrace such modified structures as come within the scope of the following claims.

Having described our invention what we claim is: V

1. A gradometer comprising, an upright housing, a shaft extending transversely of an intermediate portion of said housing on a fixed axis to provide a bearing support, a pendulum .arm including a pendulum bob disposed within said housing and supported bysaid shaft, the said pendulum arm carrying apertures below its upper extremity to receive said shaft and the upper ex-. tremity of said pendulum arm extending above said shaft, spring means depending from the upper portion of said housing and connected to the upper extremity of said pendulum arm to stabilize and to relieve the bearing weight of said pendulum arm and bob upon said shaft, a calibrated dial carried by the upper portion of said housing and having an operatively associated indicating .46

pointer and means for transmitting the motion of said pendulum arm to said indicating pointer.

said pendulum arm and bob upon said shaft, an indicating pointer operatively associated with said dial and means for transmitting the motion of said pendulum arm to said indicating pointer.

3. Thedevice of claim 2 wherein, the pendulum arm supporting means comprises, laterally bent portions provided on'opposed longitudinal sides of the pendulum arm, each of said portions being apertured to receive the supporting shaft.

' GLEN CRAFI.

VICTOR G. CARLSON.

REFERENCES CITED ,The following references are of record in the file of this patent:

UNITED STATES PATENTS

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