Technical Field
This invention pertains generally to fluid coupling assemblies, and more particularly to an apparatus for positively locking such together.
Background of the Invention
By their very nature, fluid couplings, which depend for their integrity upon one being threadably torqued into another, are subject to failure because unthreading may occur, particularly in an environment where there is vibration. The problem becomes acute where the fluids being coupled are hazardous or critical equipment failure may occur in the event of a leakage. Both undesirable states may occur where fluid being coupled is an ignitable fuel and the locale is an aircraft or space vehicle.
Currently, and perhaps the best presently known method to lock crucial fluid couplings together, is to secure them with a wire, there typically being openings in portions of mating fittings through which a wire from one to the other may be fastened. The typical problem with this means is that often the wire has too much slack or stretches, so some loosening may occur before positive locking is effected.
Another locking arrangement for locking elements of a conventional two-part fluid coupler is disclosed in U.S. Pat. No. 3,201,149. In this case, the coupling itself is specially constructed wherein a collar nut of one part of the fitting has teeth around an end which mesh with facing teeth on a locking ring of the second part of the fitting. This ring also has teeth around its internal diameter, and these fit over and lock to mating teeth on an outer diameter of a fixed portion of the second part of the fitting. This ring is spring biased to a position where the two sets of teeth are engaged wherein ultimate locking of the two parts of the fitting is effected.
It is the object of this invention to provide a locking assembly which is adapted to lock together elements of existing, standard, fluid couplers and to accomplish this by an assembly which is positive in its locking and yet is relatively simple and inexpensive to manufacture.
Summary of the Invention
In accordance with this invention, the two relatively tightenable fittings of a coupled joint are each surrounded by a sleeve contoured to firmly grip each fitting, and the sleeves have interengaging teeth. After the fitting has been tightened, these sleeves are held in place by a spring which maintains a selected engagement between the teeth of the sleeves. As the teeth are spaced at a relatively small pitch, the fitting may be quite precisely tightened and yet the sleeves effect secure tightening of them.
Brief Description of the Drawings
FIG. 1 is an exploded pictorial view, partially broken away, of the hydraulic line coupling device.
FIG. 2 is a planar view, partially broken away, of one sleeve illustrating the notch orientation.
FIG. 3 is an elevational view, partially broken away, of an assembled line-to-line coupling taken along line 3--3 of FIG. 2.
FIG. 4 is an elevational view, partially broken away, of an assembled line-to-component or bulkhead coupling taken along line 4--4 of FIG. 2.
FIG. 5 is a planar view, partially broken away, of the bulkhead and a fitting member showing the alternate pin openings.
Detailed Description of the Drawings
Referring initially to FIG. 1, there is shown an exploded view illustrating the employment of tube locking assembly 10 to lock together fitting members 12 and 14 of a conventional fitting assembly 16. Fitting member 12 includes a tubular element 18 which is connected at one end by swage joint 20 to tube 22. The opposite end 24 of element 18 is typically tapered and machined for sealably engaging a complementary surface. A collar nut 26 encircles end 24 of tubular element 18, and nut 26 is movable both rotationally and longitudinally about tubular element 18.
Fitting member 14 has an end region 30 which is coupled via a swage connection 32 to tube 34, a protruding annular nose 36 having an end region machined to engage end 24 of tubular element 18, a threaded region 38 on which nut 26 is tightened to effect connection, and hexagonal wrench gripping or nut region 40.
Locking assembly 10 includes two interlocking sleeves 42 and 44 and a split washer 46 which is nonplanar in order to function as a spring between the face 48 of nut 26 and inwardly extending shoulder 50 of sleeve 42. Sleeve 42 is generally annular, having a hexagonally keyed opening 52 sized to fit closely around nut 26 of fitting member 12 with little or no play or slippage whereby nut 26 is rotationally locked to sleeve 42. A major portion of the outer periphery of sleeve 42 is hexagonally shaped to enable gripping by a wrench (not shown). Edge 54 of sleeve 42 has a ring of ratchet teeth 56, these teeth generally extending in an axial direction. An annular notch 58 is formed between shoulder 50 and the hexagonal inner surface of sleeve 42, and split washer 46 is installed in this notch by first contracting the washer, this enabled by the split in the washer. Face 60 of fitting member 14 slips through washer 46 and sealably engages with end 24 of element 18, and during such engagement, washer 46 is pressed against shoulder 50 by nut 26. When thusly pressed, washer 46 provides a spring bias that biases sleeve 42 away from nut 26. Split washer 46 would typically be a wave or belleville washer.
Sleeve 44 is similar to sleeve 42, having a ring of ratchet teeth 62 facing and engageable with ratchet teeth 56 of sleeve 42. Ratchet teeth 56 and 62, which face each other, are configured such that, when they are compressably engaged, they enable sleeve 42 and thus nut 26 to be rotated in one direction, a tightening direction, with respect to sleeve 44 but prevent the rotation of nut 26 in an opposite direction. Hexagonally keyed opening 64 within sleeve 44 is similar to hexagonally keyed opening 52 of sleeve 42. It is sized to closely fit around gripping or nut region 40 with little or no slippage. As indicated above, gripping region 40 forms a fixed integral part of fitting member 14, and the latter is fixedly secured to hydraulic tube 34 via swage fitting 32. Shoulder 66 of sleeve 44 projects inwardly from keyed opening 64 and forms a stop for nut region 40. Thus, this shoulder prevents sleeve 44 from sliding completely over and past nut region 40. The openings within sleeve 44, sleeve 42, and washer 46 are all sized to enable threaded region 38 of fitting member 14 to extend through them for engagement with nut 26. The outer portion of sleeve 44 is hexagonally shaped to aid being gripped with a tool (not shown). Differing from that of sleeve 42, one facet 70 of side wall 72 contains a plurality of notches 74 therethrough, and each notch is radially oriented about an axis which passes through the center of opening 64 (FIG. 2). Typically, each axis is displaced from its adjacent axis by an angle of approximately 9.degree.. As will be further explained, the notches are employed when a fitting to be secured is one which is threaded into a bulkhead or some other component. The notches may be omitted where use is as shown in FIG. 1.
To examine installation of this locking device, additional reference is made to FIG. 3. First, washer 46 and sleeve 42 are fitted around collar nut 26, and sleeve 44 is fitted around nut region 40, with a portion of fitting member 14 protruding through opening 64. By means of a wrench, sleeve 42 is gripped and rotated, rotating it in a direction to tighten nut 26 on threaded region 38 of fitting member 14. While this is being accomplished, ratchet teeth 56 and 62 of sleeves 42 and 44 are biased together by washer 46; and as a result, the teeth "ratchet" or ride over each other during such rotation. After nut 26 is tightened to a desired torque, the teeth set and rotation of sleeve 42 in an opposite or loosening direction is prevented by sleeve 44 which is locked to hexagonal gripping region 40 of fitting member 14. Since fitting member 14 is fixed, nut 26 is now locked and the fitting as a whole secured from loosening.
Tube locking assembly 10 may also be employed for locking two rotatable members of fittings coupled to a bulkhead or some such component. Such an arrangement is illustrated in FIGS. 4 and 5 wherein fitting member 76 has one set of threads 78 which thread into bulkhead 80 and a second set of threads 82 which are grasped by collar nut 26 of fitting member 12. Thus, in this case, it is desirable to effect final locking to bulkhead 80 as the stationary element. Sleeve members 42 and 44 function in the manner as already described to effect a locking together of fitting member 76 and collar nut 26. To complete the locking effect, bulkhead 80 has receptacles 84 and 86, and a pin 88 is forcibly pressed into one or the other of them prior to the assembly of sleeves 42 and 44.
To determine which receptacle 84 or 86 pin 88 is to be pressed into, fitting member 76 is initially threaded into bulkhead 80 and tightened to its minimum acceptable torque pressure. Sleeve 44 is then positioned around nut region 90, and a check is made to see if one of holes 84 or 86 lines up with one of notches 74. If there is such an alignment, then sleeve 44 is removed from nut region 90, pin 88 is pressed into the aligning hole, and sleeve 44 is once again positioned around nut region 90, with pin 88 extending into the aligning notch 74. Once sleeve 44 is thereby positioned, the remaining components of tube locking assembly 10 are assembled as described.
On the other hand, should there be no such alignment between one of receptacles 84 or 86 and one of notches 74, fitting member 76 is rotated slightly to a greater torque pressure until such alignment is enabled. Then, pin 88 is pressed into the aligning hole in bulkhead 80, and locking assembly 10 is connected as indicated.
With this assembly, there are four locking interfaces. The first is between collar nut 26 and locking sleeve 42; the second is between teeth 56 and 62 of locking sleeves 42 and 44, respectively; the third is between fitting member 76 or 14 (as the case may be) and sleeve 44; and the fourth is between sleeve 44 and bulkhead 80 via pin 88. These four locking intefaces prevent the uncoupling of collar nut 26 from fitting member 76 or 14 and also the uncoupling of fitting member 76 from bulkhead 80. As shown, the locking assembly of this invention works with standard fittings and positively interlocks them to prevent them from loosening and thereby becoming a fluid coupling failure.