US3709027A

US3709027A - Proximity sensing device

Info

Publication number: US3709027A
Application number: US00108875A
Authority: US
Inventors: B Beeken
Original assignee: Automatic Switch Co
Current assignee: Automatic Switch Co
Priority date: 1971-01-22
Filing date: 1971-01-22
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

A proximity sensing device employing a fluid sensing jet which follows a helical path and which generates an above-ambient pressure signal when interrupted.

Description

United States Patent [1 1 Beeken 51 Jan. 9, 1973 [54] PROXIMITY SENSING DEVICE [75] Inventor: Basil B. Beeken, New Haven, Conn.

[73] Assignee: Automatic Switch Co., Florham Park, NJ.

[22] Filed: Jan. 22, 1971 [2]] Appl. No.: 108,875

[52] US. Cl. ..73/37.5 [51] lnt. Cl. ..G01b 13/12 [58] Field of Search ..73/37.5

[56] References Cited UNITED STATES PATENTS 3,481,180 12/1969 Jones ..73/37.5

3,545,256 12/1970 Beeken ..73/37.5 3,127,764 4/1964 Hudson ,.73/37.5 3,243,992 1/1966 Woods ..73/37.5 3,673,856 3/1970 Panigati ..73/37.5

Primary Examiner-Louis R. Prince Assistant ExaminerFrederick Shoon Attorney-Alan 1-1. Levine [57] ABSTRACT A proximity sensing device employing a fluid sensing.

jet which follows a helical path and which generates an above-ambient pressure signal when interrupted.

l3 Claims, Drawing Figures PROXIMITY SENSING DEVICE BACKGROUND OF THE INVENTION In conventional pneumatic proximity sensing devices the effective sensing range is usually limited to a small fraction of an inch. This characteristic restricts use of such sensors to those applications where the possible positional deviation of an object to be sensed from a normal position is very limited. Where an object must be sensed over a wider area other more complex sensing means must be used.

SUMMARY OF THE INVENTION The instant invention utlizes a particular kind of nozzle apparatus for generating a helical fluid stream and for directing such stream along a predetermined axis. This helical stream or jet when projected freely along said axis is capable of retaining its geometric shape over a longer distance than a conventional sensing fluid stream which moves longitudinally along said axis and thus will be able to sense the presence of objects over a greater range from said nozzle apparatus.

The primary object of the instant invention is to provide an improved fluid operated proximity sensor having a greater effective sensing range.

Another object of the invention is to provide a pneumatic proximity sensor which utlizes a helical sensing jet.

Other objects of the invention will become apparent as the disclosure progresses.

In the drawings:

FIG. 1 is an axial sectional view of a preferred embodiment of the instant invention.

FIG. 2 is a cross sectional view taken along section line 2-2 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings the instant apparatus comprises an inner member .or barrel having a reduced cylindrical tip 11, an intermediate cylinder section 12, an enlarged shoulder 13 and a cylindrical end connector portion 14. An outer tubular housing or member 15 is coaxially threadedly mounted as at 16 on said barrel so as to surround the said intermediate section 16 of said inner member thereby establishing an annular shaped flow chamber 17. The left hand end of housing 15, as seen in FIG. 1, is formed with a radially inwardly extending end wall 18 that has a radially disposed inner wall surface 20, the latter being axially spaced from the adjacent and substantially radially disposed portion of the end wall surface 21 defining the right hand end of intermediate section 12.

Surfaces

20 and 21 cooperatively define an annular orifice 22. The wall surface 21 arcuately tapers, as illustrated in the drawings, inwardly and axially so as to merge with the substantially cylindrical outer surface 23 of the said axially extending tip 11. An axial bore is formed through the barrel 10, said bore having a reduced tip portion 24, a slightly enlarged intermediate portion 25, and a further enlarged connector portion 26.

The cylindrical wall of the outer member 15 is formed with an aperture 27 in which a suitable fitting (not shown) is secured so as to allow fluid such as air to be directed tangentially into the said annular chamber 17. Further, the cylindrical wall of the intermediate barrel section 12 is formed with a relatively small radially extending bleed hole 30 which when certain pressure conditions exists, will permit a certain amount of fluid to flow from the annular chamber 17 to the said axial bore 25 in the barrel 10.

In operation supply fluid under pressure is introduced into chamber 17 through aperture 27 and flows in a helical path towards and through the annular orifice 22. After leaving orifice 22 the helical flow continues along the arcuately tapered outer surface 23 of the tip 11 and in leaving said tip will establish a miniature tornado like jet or helical flow pattern indicated at 31, the latter extending for a considerable operative range or distance d from the end of said barrel tip 11. A reduced static fluid pressure is established at the core, i.e., at the center of this free flowing helical fluid path the core also extending over the said operative distance d. This free helical flow and the reduced static pressure at the center thereof diminish to ineffective intensity at points beyond said distance a'. The reduced static pressure at the center of flow 31 causes a corresponding reduced or below-ambient pressure to exist in the bore of the barrel 1%) which in turn causes fluid to bleed from chamber 17 through bleed hole 30 and towards tip 11 as indicated by arrow 33. Under these normal flow conditions the fluid output pressure P existing at the output end of the connector bore portion 26 of barrel 10 is substantially at ambient pressure. When an object 35 to be sensed penetrates or disrupts the helical flow 31 a pressure rise will occur at'the center of said flow pattern 31 whereupon more of the fluid flow through bleed hole 30 is diverted towards the opposite end of the barrel bore as indicated by arrow 36. This will give rise to an increase in-said output pressure P to a level above the ambient level, which pressure increase will be sustained as long as the object 35 remains in a flow disrupting position as illustrated in FIG. 1. Removal of the object from intercepting relation with respect to the helical flow pattern 31 will cause the output pressure P to drop to its said normal level.

As will be apparent the above described rise in the output pressure P, constitutes a reliable indication of the presence of the object 35 within the proximity range (1 of the sensing stream and this effective range, when using a helical flow sensing jet 31, is substantially greater than where a conventional axial flow type of sensingjet is employed. Thus it may be seen that the instant proximity sensing device, in having a greater sensitivity range, is suitable for use in many applications where conventional fluid proximity sensors would be inoperative.

Since the foregoing description and drawings are merely illustrative, the scope of protection of the invention has been more broadly stated in the following claims; and these should be liberally interpreted so as to obtain the benefit of all equivalents to which the invention is fairly entitled.

I claim:

1. A fluid operated proximity sensing device: comprising a tubular barrel having a fluid guiding outer surface at one end thereof; and

means cooperating with said barrel for establishing a helical fluid flow pattern about said surface, which helical flow continues along the barrel axis beyond said end of said barrel; said means including a housing defining a chamber around said barrel;

the outer-end of said barrel having a tapered tip, the outer surface of a portion of said tip defining together with said housing an exhaust orifice from said chamber;

saidhelical flow establishing a reduced pressure at the center of said flow pattern and in the inside of saidtubular barrel, whereby when an object to be sensed interrupts said helical flow a pressure rise will be created at the center of said flow pattern and on the inside of said barreLsaid pressure rise constituting a signal indicating the presence of the object being sensed.

2. Apparatus as defined by claim 1 wherein a fluid flow conduit is provided between said chamber and the inside of said barrel.

3. A fluidoperated proximity sensing device: comprising an inner member having a fluid conducting passagewayforrned therethrough;

an outer member mounted on said inner member and formed so asto cooperatively form with said inner member a flow chamber;

said. members also defining an annular orifice through which air may exhaust in following a helical path;

the portion of said inner member helping to define said orifice being tapered; and

said outer member being formed so as to permit pressure fluid to follow a helical path towards and through said orifice whereby when an object to be sensed intercepts said helically moving fluid flow downstream of said orifice a pressure rise is generated in said passageway. 1

4. Apparatus as defined by claim 3 wherein said chamber is annular in shape, and said outer member is formed so as topermit fluid under pressure to be admitted tangentially into said chamber.

5. Apparatus as defined by claim 4 wherein said inner member is provided with a passage that interconnects said chamber and said first mentioned passageway.

6. A fluid operated proximity sensing device; comprising a housing means defining a flow chamber into which fluid is introduced so as to flow helically about an axis;

means directing said helical flow along an axis beyond the effective end of said housing means; said directing means including walls defining an annular orifice, the inner of said walls being tapered; and means defining a pressure output conduit which communicates with the center ofsaid helical flow beyond the effective end of said housing means.

Claims

1. A fluid operated proximity sensing device: comprising a tubular barrel having a fluid guiding outer surface at one end thereof; and means cooperating with said barrel for establishing a helical fluid flow pattern about said surface, which helical flow continues along the barrel axis beyond said end of said barrel; said means including a housing defining a chamber around said barrel; the outer end of said barrel having a tapered tip, the outer surface of a portion of said tip defining together with said housing an exhaust orifice from said chamber; said helical flow establishing a reduced pressure at the center of said flow pattern and in the inside of said tubular barrel, whereby when an object to be sensed interrupts said helical flow a pressure rise will be created at the center of said flow pattern and on the inside of said barrel, said pressure rise constituting a signal indicating the presence of the object being sensed.

3. A fluid operated proximity sensing device: comprising an inner member having a fluid conducting passageway formeD therethrough; an outer member mounted on said inner member and formed so as to cooperatively form with said inner member a flow chamber; said members also defining an annular orifice through which air may exhaust in following a helical path; the portion of said inner member helping to define said orifice being tapered; and said outer member being formed so as to permit pressure fluid to follow a helical path towards and through said orifice whereby when an object to be sensed intercepts said helically moving fluid flow downstream of said orifice a pressure rise is generated in said passageway.

4. Apparatus as defined by claim 3 wherein said chamber is annular in shape, and said outer member is formed so as to permit fluid under pressure to be admitted tangentially into said chamber.

6. A fluid operated proximity sensing device; comprising a housing means defining a flow chamber into which fluid is introduced so as to flow helically about an axis; means directing said helical flow along an axis beyond the effective end of said housing means; said directing means including walls defining an annular orifice, the inner of said walls being tapered; and means defining a pressure output conduit which communicates with the center of said helical flow beyond the effective end of said housing means.