GB2108664A - Device for detecting inclination - Google Patents

Abstract

A machine body inclination detector device has a float 13 constructed such that the buoyancy of the float does not undergo a great change relative to the mass when the inclination of the liquid level varies. This is achieved by making it hollow and providing weights 16 so that the top of the float is close to the level of the liquid 17. Since the buoyancy changes are small the motion of the float is damped. Partition wall 20 in the float has a small bore to damp motion of the fluid. The position of the float relative to the casing 9a, 9b, 10 is detected by proximity switches operated by steel elements 14, the switches operating a control circuit 19, V, for cylinder 6 which will thus correct the inclination of the casing and the implement on which it is mounted (Fig. 1, not shown). <IMAGE>

Description

SPECIFICATION Device for detecting inclination The present invention relates to a device for detecting changes in position of a float with respect to a body such as a machine body according to the inclination of the machine body.

Japanese Patent Publication No. SHO 5439302 discloses such a device in which vertical movement of floats floating in a U-tube effects the opening and closing of lead switches, which are a type of proximity switch, disposed adjacent this Utube, and according to such operation, carries out the level control of, for example, a rotary working machine. However the U-tube is expensive and requires a large installation space. In addition, since the floats in the U-tube are small, they are moved in an unstable manner by vibration or the like from the machine body, thus disadvantageously causing erroneous operation.

In view of the foregoing, it is an object of the present invention to restrain over-movement of floats in inclination detection devices caused by flow of the liquid in which they are immersed so as to improve the accuracy of detecting the inclination of a machine body.

Accordingly the present invention consists in a detector device for detecting inclination comprising: a container adapted to be mounted on a machine body; a liquid in said container; a float floating in said liquid and constructed such that the buoyancy of said float undergoes a small change compared with the weight of said float even though said liquid is inclined in accordance with the inclination of a body on which the device is mounted in use; and means for detecting changes in position of said float.

According to the present invention, the restoring force of the float resulting from its buoyancy when the liquid in which it is immersed is inclined, can be made very small when compared to the static inertial force of the float, thus enabling over-movement of the float resulting from its inertia and caused by flow of the liquid to be restrained, so that accuracy of detecting inclination of a body on which the device is mounted may be improved.

In order that the present invention may be more readily understood an embodiment thereof will now be described by way of example, and with reference to the accompanying drawings, in which: Fig. 1 is a side view of a rear portion of a cultivator provided with a machine body inclination detector device in accordance with the present invention; Fig. 2 is a section view of the inclination detector device mounting portion in Fig. 1; Fig. 3 is a partly cut-away plan view of a float used in the machine body inclination detector device of Fig. 1; Fig. 4 is a longitudinal section view of the float in Fig. 3; Fig. 5 is a bottom view of the float in Fig. 3; and Fig. 6 is a section view taken along the line VI--VI in the direction of the arrow in Fig. 2.

As shown in Fig. 1, a cultivator is formed in such a way that a side-drive type rotary cultivator 2 is connected in a vertically movable manner to the rear portion of a tractor 1 by a link mechanism 3 such that rotary power is transmitted from the tractor 1 to the cultivator 2.

In the link mechanism 3, one of a pair of lift arms 4 is pivotally connected to one of a pair of lower links 5 by a hydraulic cylinder 6, and the other of lift arms 4 is pivotally connected to the other of lower links 5 by a rod 7. Thus, since the lower link 5 may be swung by the cylinder 6 and the link mechanism 3 is pivotally connected to the cultivator 2, the cultivator 2 may move vertically with respect to the tractor 1.

In the cultivator 2 as shown in Fig. 2, a cast container 10 having a cover 9a and an openable lid 9b is attached to a machine frame 8 through rubber cushions 11 and a stay 11 such that the container 10 and the frame 8 may be swung together. The container 10 contains a float 1 3 and an antifreeze solution for radiator A having a specific gravity of about 1.072.

The cast container 10 has a length permitting the float 1 3 freely to move longitudinally in the container 1 0 with the distance between the container 10 and the float 13 made as small as possible, the container having a width slightly larger than the width of the float 1 3, so that the amount of horizontal movement of the float 13 in the container 10 is small.

In the plan view of the container 10, the inner corners of both longitudinal ends of the container 10 are semi-circular in plan whilst in the longitudinal section view of the container 10, the inner corners of the lower portions of both longitudinal ends S3 of the container 10 are also semi-circular.

As shown in Figs. 3 to 6, the float 1 3 is formed in a single slender shape having a substantially rectangular section, the top surface of the float 13 being convex at the centre portion thereof (Fig. 6).

The float 1 3 is provided at the longitudinal ends thereof with openings B through which the antifreeze solution A can flow into the float 1 3.

The float 13 has at the lower side of the lower wall thereof a plurality of ribs 1 9 which are spaced in the longitudinal direction.

The float 13 has a pair of elements 14 to be detected which are made of steel plate and which are located at longitudinally spaced positions.

Attached to the lid 9b are a pair of proximity switches 1 5 adapted to be respectively closed or opened by the proximity of elements 14 which are moved when the float 1 3 moves in accordance with inclinations of the machine body. The float 13 is made of polypropylene having a specific gravity of about 0.90 to 0.92. The float 13 has hollow portions 1 3a into which the antifreeze solution A flows through openings B and C. The float 13 also has a pair of metallic weights 16 such that a major portion of the lower part of the float 1 3 is immersed in the antifreeze solution A with the top surface 1 3b of the float 13 being adjacent to or projecting slightly above the level 17 of the antifreeze solution A.The float 13 is thus constructed such that the restoring force of the float 13 resulting from changes in its buoyancy when the liquid level inclines with respect to the float 13 followed by inclination of the machine body 1, are very small as compared with the inertial force or mass of the float 13.

The float 13 is provided in the top wall thereof with holes 1 8 to remove the air entering into the hollow portions 1 3a which surface on the liquid level 1 7 according to the inclination of the machine body. Thus, retention of air in the float 13 is prevented, thus preventing erroneous operation of the float 1 3 due to air entering the float 13.

The float 13 has convex end corners S2 substantially corresponding to the shape of the ends of container 10. Thus, even if the container 10 is moved sideways or lengthwise in an inclined plane or in a combination of these directions, the float 13 is barely engaged by the inner surface of the container 1 0. At the longitudinally intermediate part of each hollow portion 1 3a, there is formed integrally a partition wall 20 having therein a small bore b for the flow of the solution. Thus, the flow of the solution in the longitudinal direction in the hollow portion 1 3a is restrained by the damping action of the small bore b.Thus flow of the antifreeze solution A towards the opening B at one side of each hollow portion 1 3a caused by the vibration or the like of the machine body is prevented, such flow could provoke shaking of the entire antifreeze solution A.

Since substantially the whole float 1 3 is immersed in the antifreeze solution and shaking of the antifreeze solution contained in the container 10 is restrained, the float 1 3 is not unnecessarily shaken by vibration or temporary inclination of the machine body. In the device described changes in position and the direction of such changes of the float 1 3 with respect to the container can be detected by the opening and closing of the respective switches 15, such changes being caused by changes in the inclination of the machine body. Thus, the inclination of the machine body beyond a predetermined angle and the inclination direction can be detected.

As shown in Fig. 2, the inclination detector device is interlocked with the control valve V of the cylinder 6 so as automatically to operate the control valve V according to the inclination detection resuit of the detector device. Thus, in spite of transverse inclination of the tractor 1, a cultivating operation may be carried out whilst maintaining left- and right-hand cultivating depths substantially constant.

It is to be noted that mere water or a mixed solution of water with the antifreeze solution A can be also used, instead of the antifreeze solution A.

As alternatives to polypropylene, various synthetic resins can be used for making the float 13.

In order to make the retaining force of the float as small as possible the float may be formed so as to be completely immersed in the antifreeze solution, supports for the portions 14 to be detected being vertically attached to the float with the volume of the supports being smaller than that of the float so that the solution level is located adjacent these supports.

Of course the present invention can be applied to detector devices for detecting the inclination or pitching angle of the machine bodies, carts or construction machinery of every kind.

Claims (8)

1. A detector device for detecting inclination comprising: a container adapted to be mounted on a machine body; a liquid in said container; a float floating in said liquid and constructed such that the buoyancy of said float undergoes a small change compared with the weight of said float even though said liquid is inclined in accordance with the inclination of a body on which the device is mounted in use; and means for detecting changes in position of said float.

2. A device as claimed in claim 1, wherein the float is provided adjacent the ends of the upper surface thereof with elements to be detected, the float being constructed such that only said elements project above the level of the liquid.

3. A device as claimed in claim 2. wherein the float has longitudinal ends which are of convex shape in the plan view, and the container has concave inner corners.

4. A device as claimed in any one of the preceding claims, wherein the float has hollow portions each provided at the longitudinal ends thereof with openings, a partition wall being provided for restraining the flow of the liquid in the longitudinal direction in each of the hollow portions.

5. A device as claimed in claim 4, wherein the top surface of the float has a plurality of air vent holes communicating with the hollow portions.

6. A device as claimed in any one of the preceding claims wherein the float has weights adjacent both ends of the lower wall of the float.

7. A device as claimed in any one of the preceding claims, wherein at least a portion of the liquid is constituted by an antifreeze solution.

8. A device for detecting inclination substantially as hereinbefore described with reference to the accompanying drawings.