US3858737A

US3858737A - Excavator

Info

Publication number: US3858737A
Application number: US309888A
Authority: US
Inventors: Rikizo Senoo
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-02
Filing date: 1972-11-27
Publication date: 1975-01-07
Anticipated expiration: 1992-01-07
Also published as: DE2257951A1; JPS4869202U; JPS5148805Y2; GB1404617A; DE2257951B2; FR2162172B1; FR2162172A1

Abstract

An improved excavator which is provided with a transmitter, a receiver and antennae of a buried metal detector, being characterized in that said antennae comprise three antennae which are disposed in the bucket arm of said excavator in three dimensional perpendicular relation, and thereby the damages of buried metal facilities can be prevented.

Description

United States Patent [191 Appl. No.: 309,888

Foreign Application Priority Data Field of Search 214/761, 762, 764; 324/41 324/67; 37/DlG. 19; 56/102, D16. 15

References Cited UNITED STATES PATENTS Maust 37/D1G. l9

[111 3,858,737 Senoo 3 1 1 Jan. 7, 1975 [5 EXCAVATOR 2,409,397 l0/l946 Sheehan r. 37/DlG, 19 [76] Inventor: Rikizo Senoo, 2-14, Nihombashi figgfigfff Kakigara-cho, Chuo-ku, Tokyo,

Japan Primary ExamtnerRobert J. Spar i 1 Fllfidi 1972 Assistant Examiner-John Mannix Attorney, Agent, or FirmLerner, David, Littenberg & Samuel [57] ABSTRACT An improved excavator which is provided with a transmitter, a receiver and antennae of a buried metal detector, being characterized in that said antennae comprise three antennae which are disposed in the bucket arm of said excavator in three dimensional perpendicular relation. and thereby the damages of buried metal facilities can be prevented.

3 Claims, 6 Drawing Figures PATENTED JAN 7 5 SHEEF 2 OF 2 mumSsw mwk 0Q EXCAVATOR FIELD OF THE INVENTION The present invention relates to an improved excavator for digging the soil. Further, the invention relates to the excavator which is provided with a transmitter, a receiver and antennae of a buried metal detector being characterized in that said antennae comprise three antennae and positioned in the bucket arm of the excavator in three dimensional perpendicular relation. Still further, the invention relates to the excavator which can detect the buried metal facilities to stop the bucket arm thereof.

BACKGROUND OF THE INVENTION Excavators are generally employed for digging the soil in construction site, and if the public facilities such as city-water pipes, gas pipes, electricity cables and telephone cables are buried in the ground, these facilities are liable to be damaged by the digging bucket of the excavator during the construction work. And when these accidents are brought about, the dwellers in the neighbourhood are caused several troubles such as failures of water supply and power supply, and inundation, in addition to that they incur the damage of their lives by the accident such as explosion of the city-gas.

Therefore, the object of the invention is to prevent such accidents and troubles from occurring. Further object of the invention is to provide a novel excavator which can proceed the digging work without causing such accidents and troubles, i.e. the damages of water pipes, gas pipes, electricity cables and telephone cables.

BRIEF SUMMARY OF THE INVENTION Pursuant to the above objects, the present invention proposes an improved excavator which is provided with a transmitter, a receiver and antennae of a buried metal detector, in which said antennae comprise three antennae attached to the bucket arm portion of the excavator, and is disposed in three dimensional perpendicular relation with each other. Further, the receiver as provided can be interlocked to the driving source of the bucket arm, thereby when the signal form a buried metal article is detected, the work of the bucket is immediately stopped to prevent the damage of said article.

BRIEF DESCRIPTION OF THE DRAWINGS These and other feature of the invention will be more fully understood by referring to the following detailed description presented solely for the purpose of illustration and to the accompanying drawings in which:

FIG. 1 is a schematic illustration of the use of the excavator;

FIG. 2 is a plan view of the bucket in which the antennae are diposed according to the invention;

FIGS. 3, 4 and 5 are diagrams showing the characteristics of the buried metal detector and FIG. 6 shows the interlocking of the power source of the excavator of FIG. 1 with a receiver in accordance with one aspect of this invention.

DETAILED DESCRIPTION OF THE INVENTION Now referring to the drawings, the excavator of the present invention will be explained. In the drawings,

the numeral 1 indicates a back hoe, the numeral 2 is a digging arm of the back hoe 1, and the

numerals

3, 4 and 5 are bar antennae. As shown in FIG. 2, the

bar antennae

3, 4 and 5 are disposed adjacently to the bucket 6 of the digging arm 2 in three dimensional arrangement imaliifih'r, i.e., in the perpendicular relations. The numeral 7 is a transmitter of a buried metal detector and the numeral 8 is a receiver, both of which are installed within the back hoe 1. Further, the numeral 9 indicates a buried metal pipe.

The transmitter 7 and the receiver 8 of the buried metal detector which are employed in the device of the present invention, have respective loop coils. In general, when these loop coils are positioned on the ground perpendicularly, the directivity of the electromagnetic wave shows the figure 8 characteristic as shown in FIG. 3. Accordingly, the intensity of the electromagnetic wave is most strong in the direction of A A, and in other directions, for example, in the directions of B and C, the intensity decreases gradually, and at last the intensity of the electromagnetic wave becomes the minimum.

Thus, when the transmitter 7 is put up on the ground, the electromagnetic wave is radiated into the ground, and if a metallic article such as a metal pipe or cable is buried in the ground, the electromagnetic'field is induced by said metallic article as shown in FIG. 4. The intensity of this electromagnetic wave becomes larger, if the metallic article is buried in a shallow place, or the metallic article is large or the direction of the metallic article is parallel to the face of the coil. While, if the direction of the metallic article is inclined to the face of the coil in like manner as the arrow B or C in FIG. 3, the intensity of the electromagnetic wave is reduced as much. In case a receiver is placed in the electromagnetic field thus induced, several receiver sensitivities will be obtained according to the position of the receiver. As indicated in FIG. 5, if the receiver 8 is positioned in the magnetic field of the electromagnetic wave 10 which is induced by the transmitter 7, the receiver sensitivity is largest in the position E, it is decreased in some degree in the position F, and it is the minimum in the position G. And the farther the receiver is moved away, the smaller the receiver sensitivity becomes, as indicated by the mark H.

The buried metal detector has the above-mentioned characteristic, thus the transmitter is placed previously just above the buried metal pipe in adjacent to the construction site, in which the loop coil of the transmitter is disposed in paralles with the buried metal 9, thereby the electromagnetic field is produced on the buried metallic pipe 9. Accordingly, if the aforementioned back hoe 1 get near the buried pipe 9, the pipe 9 in any direction can be detected by the set of three

antennae

3, 4 and 5 which are attached on the digging arm 2 of the back hoe l in three perpendicular directions. In the meantime, by interlocking the receiver 8 with the power source 11 of the back hoe 1, via lead 12 (see FIG. 6) the latter can be totally stopped just upon the detection of the buried metallic pipe 9 by said antennae. Further, the distance between the buried pipe 9 and the top portion of the bucket 6 of the back hoe I in which the back hoe l is to be stopped, can be regulated by adjusting the sensitivity of the receiver 3.

Thus if the device of the present invention is used in the excavation work, the buried pipe 9 is never caused damage because the back hoe 1 can be stopped immediately on the detection of the pipe 9 by the

antennae

3, 4 and 5. Therefore, the device of the present invention is very effective and advantageous in the construction site.

Further, in order to turn back the stopped bucket 6 of the back hoe l, the conventional electromagnetic relay can be used according to well known manner.

It should be emphasized, however, that the specific embodiments described and shown herein are intended as merely illustrative and in no way restrictive of the invention.

What is claimed is:

1. An excavator having a bucket arm and which is when a signal is received by said receiver.

Claims

1. Ajn excavator having a bucket arm and which is provided with a buried metal detector including a transmitter, a receiver and an antennae, in which said antennae comprises three elements; said three elements being positioned on said bucket arm of said excavator and are disposed in three-dimensional mutually perpendicular relationship with each other.

2. An excavator as defined in claim 1 in which said three elements are bar antennae.

3. An excavator as defined in claim 1 also including: means for interlocking said receiver to the driving source of said bucket arm to stop said bucket arm when a signal is received by said receiver.