TOOL MONITORING APPARATUS

• US 3,747,085 A
• Filed: 11/03/1971
• Issued: 07/17/1973
• Est. Priority Date: 11/03/1971
• Status: Expired due to Term

• Current Assignee: John L. Bala, Peter W. Ford
• Original Assignee: John L. Bala, Peter W. Ford
• Inventors: Bala, John L., Ford, Peter W.
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US05/195,397
• Time in Patent Office: 622 Days
• Field of Search: 340/267R,282,271,195,421 408/6 324/34PS,41
• US Class Current: 340/680
• CPC Class Codes: B23B 49/001 Devices for detecting or indicating failure of drills
• CPC Class Codes: B23Q 17/0947 Monitoring devices for measuring cutting angles
• CPC Class Codes: Y10T 408/14 Responsive to condition of Tool or tool-drive

Abstract

Apparatus for monitoring the condition of a tool and for detecting the improper operation thereof. The apparatus utilizes a magnetic circuit formed of a first low reluctance portion and a second high reluctance portion having a pulsating magnetic flux induced therein. In normal operation, the tool to be monitored is adapted to be positioned within and substantially bridge the high reluctance portion, which preferably comprises an air gap, and become a part of the circuit thus greatly lowering its reluctance. Appropriate electronics are provided to monitor abrupt and significant increases in the reluctance due to withdrawal of the tool from the air gap caused by breakage or loss of the tool. The sensing portion of the apparatus is manufactured as an enclosed unit which may be adapted to monitor tools of various types and sizes.

Claims

1. Tool monitoring apparatus comprising:

a. a housing; and

b. sensing means positioned within said housing for sensing an elongated tool which may be of diverse widths and which is to be positioned through said housing and said sensing means, said sensing means including;

1. a magnetic circuit having a pair of aligned tapered pole portions between which an air gap for receipt of said tool to be sensed is to be formed by removing sufficient amounts of said tapered portions to provide an air gap having a width substantially identical to that of said tool to be sensed;

2. an input winding in inductive relationship with said circuit and having a pair of input terminals adapted to be coupled to a source of pulsating voltage; and

3. an output winding in inductive relationship with said circuit and having a pair of output terminals adapted to be coupled to a monitoring circuit.

2. Apparatus as recited in Claim 1 wherein said aligned tapered pole portions are joined together by a connecting portion which is adapted to be removed along with sufficient amounts of said tapered portions to form said air gap.

3. an output winding in inductive relationship with said circuit and having a pair of output terminals adapted to be coupled to a monitoring circuit.

4. Apparatus as recited in Claim 1 wherein said housing includes indicia means for identifying the position at which said air gap is to be formed through said housing and said circuit.

5. A method for monitoring the condition of movable elongated tools which may be of diverse widths comprising the steps of:

a. providing a magnetic circuit means through which said tool to be monitored is to be passed, said magnetic circuit means including a low reluctance portion;

b. removing sufficient amounts of said low reluctance portion to provide an air gap having a width substantially identical to the width of the tool to be monitored;

c. passing said tool to be monitored through said air gap; and

d. monitoring the reluctance of said magnetic circuit means and generating a signal upon a change in the reluctance thereof indicative of the improper condition of said tool.

6. A method as recited in claim 5 wherein said tool to be monitored comprises a drill and wherein said removing step comprises drilling a hole through said low reluctance portion with said drill to be monitored.

7. A method as recited in claim 5 wherein said low reluctance portion includes a pair of aligned tapered pole portions and wherein said removing step comprises drilling away sufficient amounts of said pole portions to provide an air gap therebetween having a width substantially identical to the width of said tool to be monitored.

8. A method as recited in claim 5 wherein said magnetic circuit means is contained within a substantially enclosed housing and wherein said removing step comprises drilling through both said housing and said circuit means to provide said air gap for receipt of said tool to be monitored.