Patent Description:
Pressured fluid systems, whether hydraulic or pneumatic, are common in many industrial environments, distributing pressured fluid from a fluid source, such as a pump, compressor, or pressurized storage vessel, to an end-use device that can include hydraulic or pneumatic motors, actuators, cylinders, rivet squeezers, rivet guns, nozzles, and sprayers, among other possible end-use devices. Downstream from the fluid source, a regulator sets fluid pressure supplied to the end-use device. Excessive fluid pressure, excessive fluid flow rate, or both can cause the end-use device to perform poorly and, in some cases, damage the tool, machine or product as well as injure an operator of the end-use device.

Attempts to prevent damage to end-use devices and mitigate operator risk include inline fixed flow devices and inline adjustable flow control valves. However, such devices are discrete from other devices, fittings, and valves within the system, increasing the number of connections within the system and, hence, increasing potential failures of the system. Further, inline fixed and adjustable flow control devices may be collocated with the operator, increasing weight and reducing the flexibility of the line connected to the end-use device, reducing operability of the device.

<CIT> discloses a valve plug threadedly engaged with a valve stem so as to be inserted from an open end of a passage for charging with and/or releasing from a compressed fluid, toward an inner part of the passage, thereby closing an inner smaller diameter portion. <CIT> discloses a flexible coaxial conduit in a recirculating paint supply system disposed between a flow control restrictor connected to a paint spray nozzle and a pressurized paint supply line and return line for supplying paint to the nozzle in a quantity in excess of that required to provide continued recirculation and uniformity in the composition and quality of the liquid coating composition.

<CIT> discloses a fitting comprising:a body comprising:an interior surface that includes a first bore extending from a first end of the body and a second bore extending from a second end of the body, wherein the first end of the body defines an inflow port coaxial with an outflow port defined by the second end of the body; and an exterior surface that includes a quick disconnect profile at the first end and an external thread at the second end.

In an aspect, the present disclosure provides a fitting comprising: a body comprising: an interior surface that includes a first bore extending from a first end of the body and a second bore extending from a second end of the body, wherein the first end of the body defines an inflow port coaxial with an outflow port defined by the second end of the body; and an exterior surface that includes a quick disconnect profile at the first end and an external thread at the second end; and a pin disposed within the second bore, the pin comprising: a first portion having a rotationally symmetric profile about a longitudinal axis of the pin that extends towards the first bore; a second portion adjacent to the first portion and between the first portion and the second end of the body, an outer periphery of the second portion engaging the interior surface at the second bore; and a plurality of bypass passages circumferentially distributed about the longitudinal axis and extending through the second portion of the pin; and an adjustment member disposed within the first bore, the adjustment member comprising a cylindrical body and a third bore concentric with an outer periphery of the cylindrical body and extending through the cylindrical body; wherein the second bore and the bypass passages bound a passage extending through the fitting; and wherein a minimum cross-sectional area of the passage coincides with the first portion of the pin, wherein an axial position of the adjustment member is variable to vary the minimum cross-sectional area of the passage defined between the first portion of the pin and the third bore.

In a fitting, not according to the invention as defined by the claims, only shown as an example, the second portion of the pin includes external threads engaging internal threads of the second bore and a tool interface formed by an end face of the second portion that is accessible from the second end of the body. Axial translation of the pin provided via the tool interface and external threads operate to vary the minimum cross-sectional area defined between the first portion of the pin and the first bore.

The fitting includes a cylindrical adjustment member that includes external threads engaging internal threads of the first bore and a tool interface formed in an end face of the adjustment member accessible from the first end of the body. In this embodiment, the outer periphery of the pin and the second bore form a location fit or an interference fit to axially restrain the pin relative to the body. Axial translation of the adjustment member via the tool interface and external threads of the adjustment member vary a minimum cross-sectional area formed between the first portion of the pin and a third bore extending through the adjustment member.

As disclosed herein, a fitting equipped with a flow-limiting device simultaneously limits flow rate of fluid delivered to an end-use device while providing a quick disconnect coupling for easily attaching and detaching the end-use device from the fluid supply system. In one embodiment, the quick disconnect fitting includes a flow-limiting device formed by an orifice bore defined by a minimum diameter of the fitting extending into the fitting body. The selected diameter and length of the orifice bore is end-use specific, larger diameters required for greater flow rates and smaller diameters implemented for lesser flow rates when supplied with a given line pressure. Quick disconnect fittings with integral fixed orifices can be used for a range of line pressures supplied to the end-use devices. Alternatively, a family of fixed flow rate quick disconnect fittings can be used, each fitting tailored to deliver a particular flow rate given one of several line pressure settings. In other embodiments, the flow rate through the quick disconnect fitting can be variable by adjusting a position of a pin contained within the fitting or by adjusting the position of another element relative to a fixed pin. In both embodiments, the pin and the adjacent component, whether a bore of the fitting body or of an adjustable element, form an orifice to thereby limit flow rate of fluid discharged into the end-use device. Further, in each of the fitting embodiments described below, a single fitting performs both a flow-limiting function as well as forms a quick disconnect coupling, protecting the end-use device from damage and its operator from injury resulting from excessive fluid flow rates or fluid pressures while reducing the overall weight and improving operability of the end-use line assembly.

End-use devices can include any hydraulic or pneumatic device, or any device used to discharge pressurized fluid at a particular flow rate. Example end-use devices include rivet squeezers and rivet guns used for the manufacture of aircraft as well as hydraulic or pneumatic motors, drills, jacks, cylinders, actuators, sprayers, and nozzles among other potential hydraulic or pneumatic end-used devices.

As described below, exemplary fitting embodiments are depicted and described as male quick disconnect fittings adapted to be mated with the corresponding female quick disconnect fitting attached to the fluid system. The following embodiments reference quick disconnect fitting geometry corresponding to ISO 6150B, a spring-loaded ball-latching mechanism typical for pneumatic systems. However, other quick disconnect geometry could be used.

<FIG> is an isometric exterior view of fitting <NUM> while <FIG> depicts a cross-sectional view of fitting <NUM> taken along line A-A which is parallel and coincident to axis <NUM> that defines a geometric centerline of fitting <NUM>. Fitting <NUM> includes body <NUM> bound by exterior surface <NUM>, interior surface <NUM>, and end faces <NUM> and <NUM>. Exterior surface <NUM> includes quick disconnect profile 16A extending from end face <NUM> as well as external thread 16B extending from end face <NUM> located opposite quick disconnect profile 16A. External threads 16B of fitting <NUM> can be formed to any suitable thread standard but is depicted in <FIG>, <FIG>, and subsequent figures with national pipe threads (NPT) according to ANSI/ASME standard B1. <NUM>, which can be used to join fitting <NUM> to an end-use device (not shown) such as a pneumatic sprayer, rivet gun, rivet squeezer, or other pneumatic tool or device. Intermediate of quick disconnect profile 16A and external thread 16B, exterior surface <NUM> includes hex 16C according to metric or British standards to facilitate attachment of fitting <NUM> to an end-use device by using a wrench, a socket, or other similar tool. Additionally, exterior surface <NUM> can include marking 16D, which can be used by an operator to identify the orifice size of fitting <NUM>.

Features of interior surface <NUM> include bores 18A, 18B, and 18C, each concentrically disposed about axis <NUM> and bounding passage <NUM>, which extends through fitting <NUM> from end face <NUM> to end face <NUM>. Bore 18A, bore 18B, and bore 18C have sequentially decreasing respective diameters D1, D2, and D3 as depicted by <FIG>. Bore 18A extends from end face <NUM> of fitting <NUM> length L1 to bore 18B, which extends length L2 from an interior end of bore 18A to bore 18C. Intermediate transitions between bore 18A and bore 18B as well as between bore 18B and 18C may be terminated with a bottom chamfer as shown. Bore 18C extends length L3 from bore 18B to end face <NUM> to form an orifice of fitting <NUM> having diameter D3, which is the minimum diameter of passage <NUM>. For instance, diameter D3 can be between <NUM> inches (<NUM>) and <NUM> inches (<NUM>) for pneumatic systems with line pressures between <NUM> psi and <NUM> psi. In some embodiments, diameter D3 can be larger or smaller to limit the fluid flow rate into end-use device for a given line pressure P, or a range of line pressures P, provided at bore 18C. In other embodiments, diameter D1 is at least three times diameter D3 and length L3 is at least three times diameter D3. Factors influencing the geometry of bores 18A and 18B (i.e., D1, L1, D2, L2) include minimizing pressure loss of fluid flowing exiting bore 18C into bore 18b as well as optimizing principle stress within fitting body <NUM>. For instance, diameter D2 of bore 18B is less than diameter D1 of bore 18A and greater than diameter D3 of bore 18C to accommodate quick disconnect profile 16A of fitting <NUM>. Length L2 of bore 18B resides with a region between bore 18A and bore 18C that it coincides, at least partially, with quick disconnect profile 16A to increase the cross-section of body <NUM> within this region and thereby reducing stress. In other embodiments, fitting <NUM> may not include intermediate bore 18B, the geometry of body <NUM> permitting bore 18A to extend from end face <NUM> to bore 18C.

In operation, fitting <NUM> connects to an end-use device at external thread 16B and connects to a system containing fluid at line pressure P via quick disconnect profile 16A. While operating the end-use device, fluid may continuously or periodically flow into end-use device through fitting <NUM>. When fluid flows through fitting <NUM>, the fluid flow rate delivered from the system into the end-use device is reduced primarily as a result of the pressure drop of fluid flowing through bore 18C. This flow rate reduction operates to slow down operation of the end-use device. However, when fluid does not flow through fitting <NUM>, the pressure of fluid within fitting <NUM> equalizes with the pressure of fluid within the system.

<FIG>, <FIG> are various views of fitting 10A within an externally adjustable orifice arrangement formed between pin <NUM> and adjustable member <NUM> assembled within body <NUM> of fitting 10A. <FIG> is an exploded view of fitting 10A in which pin <NUM> and adjustable member <NUM> are removed from body <NUM> of fitting 10A whereas <FIG> is an isometric view of fitting 10A with pin <NUM> and adjustable member <NUM> assembled within opposite ends of body <NUM>. <FIG> is an end view of fitting 10A as viewed from line B-B that depicts pin <NUM> in an assembled position within body <NUM>. <FIG> is a cross-sectional view of fitting 10A taken along line C-C while <FIG> is the opposite end view of fitting 10A taken from line D-D that depicts adjustable member <NUM> assembled in a nominal position within fitting 10A.

As shown generally in <FIG> and more specifically in <FIG>, body <NUM> of fitting 10A is bound by exterior surface <NUM>, interior surface <NUM>, and end faces <NUM> and <NUM>. Exterior surface <NUM> includes quick disconnect profile 32A extending from end face <NUM> of fitting, external thread 32B extending from end face <NUM>, and hex 32C interposed between quick disconnect profile 32A and external thread 32B, each feature formed and functioning in a manner analogous to fitting <NUM>. Internal surface <NUM> includes bore 34A extending from end face <NUM> towards and joining with bore 34B that extends to end face <NUM>. Bore 34A and bore 34B are concentrically disposed about axis <NUM> that extends through the geometric centers of bore 34A, bore 34B, end face <NUM>, and end face <NUM>. Bore 34A includes internal thread 34C for receiving adjustment member <NUM>, discussed below.

In an assembled position best depicted by <FIG>, pin <NUM> is concentrically installed within bore 34B such that longitudinal axis <NUM> of pin <NUM> is coincident with axis <NUM> of body <NUM>. An end of pin <NUM> closest to end face <NUM> includes support region 26A formed by a cylindrical body modified to include at least two bypass passages <NUM>, which intersect outer peripheral surface <NUM> of support region 26A to form an equal number of ribs <NUM>. Bypass passages <NUM> are interposed between adjacent ribs <NUM> and circumferentially distributed about longitudinal axis <NUM>. As shown by <FIG>, pin <NUM> includes four bypass passages <NUM> and four ribs <NUM> equally distributed about longitudinal axis <NUM>. However, in other embodiments, pin <NUM> can include three bypass passages or greater than four bypass passages <NUM>, as flow rate and stress requirements allow. Generally, a net cross-sectional area of the bypass passages <NUM> is greater than the minimum cross-sectional area defined between interior region 26B of pin <NUM> and adjustable member <NUM>, as discussed in greater detail below. Outer peripheral surface <NUM> of support region 26A can form a location fit, threaded fit,or interference fit with interior surface <NUM> at bore 34B that thereby restrains pin <NUM> axially relative to body <NUM>.

Interior region 26B of pin <NUM> protrudes from support region 26A towards adjustment member <NUM>. An outer peripheral surface of interior region 26B defines profile <NUM>, which is rotationally symmetric about longitudinal axis <NUM> of pin <NUM>. Profile <NUM> defines a monotonically decreasing surface extending from a maximum diameter Dmax adjacent or proximate to support region 26A to a minimum diameter Dmin at or near a tip of pin <NUM> distally located from support region 26A. As shown in <FIG>, profile <NUM> is frustoconical. In other embodiments, profile <NUM> can be entirely conical, cylindrical, concave, elliptical, or parabolic while in still other embodiments, profile <NUM> can be any of the foregoing shapes truncated at the distal pin tip to form an end face or can form a hybrid profile comprised of any combination of the foregoing profiles. For example, profile <NUM> can be conical or cylindrical adjacent to support region 26A transitioning to a concave, elliptical, or parabolic profile near the distal tip of pin <NUM>, which may or may not be truncated to form an end face.

Additionally, profile <NUM> can be characterized by a slope equal to a change in diameter ΔD divided by length Lp of profile <NUM>, or a portion of profile <NUM>, over which the change in diameter occurs and in which length Lp is measured parallel to longitudinal axis <NUM>. Aggressive or steep slope profiles <NUM> have larger diameter changes over a given length Lp than less aggressive or shallow slope profiles <NUM>. While aggressive slope profiles provide more flow owing to a shorter length of interior region 26B overlapping with or in close proximity to adjustment member <NUM>, aggressive slope profiles provide coarser adjustment of the minimum cross-sectional between pin <NUM> and adjustment member <NUM>. By contrast, less aggressive or shallow slope profiles <NUM> tend to permit finer adjustment of the minimum cross-sectional area and, hence, finer adjustment of the flow through fitting 10A. However, the length of overlap between interior region 26B of pin <NUM> and adjustment member <NUM> is greater and, therefore, tends to restrict more flow relative to aggressive slope profiles <NUM>.

Adjustment member <NUM> is a cylindrical body in which bore <NUM> extends entirely through the cylindrical body of adjustable member <NUM> along centrally-located axis <NUM>. Exterior surface <NUM> of adjustment member <NUM> includes external threads 56A compatible with interior threads 34C located within bore 34A of body <NUM>. Any suitable thread standard can be implemented for interior thread 34C and external thread 56A. Typical options include coarse (UNC), fine (UNF), and extra fine (UNEF) profiles of the unified screw thread standard as well as metric thread standard defined by ISO <NUM>-<NUM> and related standards. Finer thread profiles provide finer adjustment of a minimum cross-sectional area defined between pin <NUM> and adjustment member <NUM>, allowing for a more precise flow adjustment setup for fitting 10A. Adjustment member <NUM> may include tool interface <NUM> formed by end face <NUM> of adjustment member <NUM>, which is accessible from end face <NUM> of the fitting body. As shown, tool interface <NUM> is a slotted profile for a flat head screwdriver. However, any other type of screwdriver profile can be used as well as any socket size adapted for a hex or square driver. In yet another embodiment, tool interface <NUM> can be formed by bore <NUM> or a portion of bore <NUM> itself. For example, the entire length of bore <NUM> or a portion of bore <NUM> extending from end face <NUM> may take the form of a square or hex socket for a square or hex driver. Whichever interface is selected, tool interface <NUM> permits end face <NUM> of adjustment member <NUM> to be flush with end face <NUM> of body <NUM> in a normally installed position.

Rotating adjustment member <NUM> via tool interface <NUM> axially translates adjustment member <NUM>, via external threads 56A, towards or away from interior portion 26B of pin <NUM> to vary a minimum cross-sectional area of fitting 10A and thereby vary a flow rate through fitting 10A. Dashed line <NUM> represents adjustment member <NUM> at a position intermediate of a nominal, maximum opening position as shown in <FIG> and a fully-closed position show at dashed line <NUM>. The minimum cross-sectional area Amin of the passage through fitting 10A is represented by shaded zone depicted in <FIG>. However, it will be appreciated that as adjustment member <NUM> moves axially relative to fixed pin <NUM>, minimum cross-sectional area Amin changes and consequently varies a flow rate delivered to end-use device. Moreover, since fitting 10A attaches to an end-use device via external thread 32B and connects to the system containing fluid at line pressure P via quick disconnect profile 32A, the flow rate through fitting 10A, as determined by varying a position of adjustment member <NUM>, can be changed prior to or after connecting end-use device to the system via fitting 10A. In operation, fluid received from the system enters fitting 10A through bore <NUM> of adjustment member <NUM> before passing through minimum cross-sectional area defined between adjustment member <NUM> and interior region 26B of pin <NUM>. Fluid passes through bypass passages <NUM> in support region 26A and bore 34B as it exits fitting 10A into end-use device.

<FIG>, <FIG> are various views of an internally adjustable orifice arrangement formed between pin <NUM> and body <NUM> of fitting 10B. <FIG> is an isometric exploded view of fitting 10B showing pin <NUM> separated from body <NUM> of fitting 10B while <FIG> depicts pin <NUM> fully assembled and pin <NUM> in a nominal position. <FIG> is an end view of fitting 10B as viewed from line E-E. <FIG> is a cross-sectional view of fitting 10B taken along line F-F. Components and features identified with like reference numbers take a similar form and have analogous functions for fitting 10B except as described below.

Principally, fitting 10B differs from fitting 10A in that adjustment member <NUM> is not required, and instead, pin <NUM> is used to vary minimum cross-sectional area Amin of fitting 10B defined between interior region 26B of pin <NUM> and bore 34A of fitting body <NUM>. In this embodiment, body <NUM> of fitting 10B has internal thread 34C within bore 34B that engage external thread 46A formed on peripheral outer surface <NUM> of pin <NUM>. Additionally, tool interface <NUM> is formed by end face <NUM> of pin <NUM> closest to end face <NUM> of the fitting body. By rotating pin <NUM> using of threads 34C-46A and tool interface <NUM>, pin <NUM> of fitting 10A can be positioned from the nominal, fully-open position shown by <FIG> to a fully-closed position indicated by dashed line <NUM> as well as any intermediate position represented by dashed line <NUM>. Accordingly, minimum cross-sectional area Amin as represented by the shaded area at position <NUM> can vary and thereby vary a flow rate of fluid delivered to end-use device connected via external threads 32B of fitting 10B. Hence, flow-rate adjustment of fitting 10B can be accomplished only when fitting 10B is disconnect from end-use device and thereby provides assurance that a flow rate setting will remain unchanged between successive operations of end-use device.

In operation, flow enters fitting 10B from system through bore 34A and flows through minimum cross-sectional area Amin. Exiting minimum cross-sectional area Amin, fluid flows through bore 34B and through bypass passages <NUM> before entering end-use device connected to fitting 10B via external threads 32B.

Claim 1:
A fitting (10A, 10B) comprising:
a body (<NUM>) comprising:
an interior surface (<NUM>) that includes a first bore (34A) extending from a first end (<NUM>) of the body (<NUM>) and a second bore (34B) extending from a second end (<NUM>) of the body (<NUM>), wherein the first end (<NUM>) of the body (<NUM>) defines an inflow port coaxial with an outflow port defined by the second end (<NUM>) of the body (<NUM>); and
an exterior surface (<NUM>) that includes a quick disconnect profile (32A) at the first end (<NUM>) and an external thread (32B) at the second end (<NUM>); the fitting being characterized in that it comprises:
a pin (<NUM>) disposed within the second bore (34B), the pin (<NUM>) comprising:
a first portion (26B) having a rotationally symmetric profile (<NUM>) about a longitudinal axis (<NUM>) of the pin (<NUM>) that extends towards the first bore (34A);
a second portion (26A) adjacent to the first portion (26B) and between the first portion (26B) and the second end (<NUM>) of the body (<NUM>), an outer periphery of the second portion (26A) engaging the interior surface (<NUM>) at the second bore (34B); and
a plurality of bypass passages (<NUM>) circumferentially distributed about the longitudinal axis (<NUM>) and extending through the second portion (26A) of the pin (<NUM>); and
an adjustment member (<NUM>) disposed within the first bore (34A), the adjustment member (<NUM>) comprising a cylindrical body and a third bore (<NUM>) concentric with an outer periphery of the cylindrical body and extending through the cylindrical body;
wherein the second bore (34B) and the bypass passages (<NUM>) bound a passage extending through the fitting (10B); and
wherein a minimum cross-sectional area (Amin) of the passage coincides with the first portion (26B) of the pin (<NUM>), wherein an axial position of the adjustment member (<NUM>) is variable to vary the minimum cross-sectional area (Amin) of the passage defined between the first portion (26B) of the pin (<NUM>) and the third bore (<NUM>).