US3391602A - Frequency responsive lubrication system - Google Patents

Description

FREQUENCY RESPONSIVE LUBRICATION SYSTEM 2 Sheets-Sheet 1 Filed July 10, 1967 FIG.I

INVENTORSI GEORGE VD. BROOKS,

DALE A. FARRINGTON,

JOHN E. FOLEY, BY 1% C- THEIR ATTORNEY.

July 9, 1968 BROOKS 3,391,602

FREQUENCY RESPONSIVE LUBRICATION SYSTEM Filed July 10, 1967 2 Sheets-Sheet 2,

u so i 7 II 2, 7 66 a2 46 j J. 5 84 as 89 FIG.4

3 GUN DISPLACEMENT 5 AT 70 e IOOCPS Z T Z IJJ 2 3 f, PUMP (PISTON ROD) DISPLACEMENT O. m 5 .06

TIME

INVENTORS'. GEORGE D. BROOKS, DALE A. FARRINGTON, JOHN E. FOLEY,

THEIR ATTORNEY.

United States Patent O 3,391,602 FREQUENCY RESPONSIVE LUBRICATION SYSTEM George Dewey Brooks, South Burlington, and Dale Andrew Farrington, Winooski, Vt., and John Emmet Foley, Longmeadow, Mass., assignors to General Electric Company, a corporation of New York Filed July 10, 1967, Ser. No. 652,308 4 Claims. (Cl. 89-1) ABSTRACT OF THE DISCLOSURE In combination, a very high rate of fire automatic weapon operating on the Gatling-gun principle and a frequency responsive device for delivering lubricant to the internal gun mechanism. The device comprises a lubricant reservoir, pick-up and delivery lines, and a piston operable against a spring force, in a pump chamber connecting the lines, by a weight or mass attached to the piston rod. The reservoir is mounted on the gum and the weight-rod-piston selected to act as a vibrating massspring system at gun operating frequencies.

Background of the invention It is well known to use lubricating devices for guns wherein cams or levers are operated by gun recoil to pump lubricant to the internal gun mechanism. In such manner a gun bolt which rides on a track in the receiver may be continuously supplied with oil or grease. Such devices are usually somewhat undesirable under adverse field conditions, however, since reliability sufiers the more complex the apparatus. It is also known to use mass or weight which, when suddenly accelerated, can be used to do work through the effects of inertia. That is, if attached to a lever which remains stationary, for example, the inertia of the suddenly accelerated mass will apply a force to the lever which can be made to do useful work. Such a device would be more reliable in concept than the typical recoil-operated cam and lever arrangement. Means are needed, however, to adapt this for use with a modern, high rate of fire weapon operating on the Gatling-gun principle. Such a weapon is described in detail in the patent to Otto 2,849,921. Due to its extremely high rate of fire the modern day Gatling-gun, as shown in Ottos patent, establishes what may be termed an operating frequency of vibration as the six (or more) gun bolts reciprocate in the rotor tracks which are revolving about the gun axis. We have taken advantage of this phenomenon to provide an improved and simplified means of internally lubricating such a weapon.

Accordingly, a general object of our invention is to provide an improved lubricating device for a high rate of fire automatic weapon.

A more specific object of our invention is to provide, in combination, a high rate of fire automatic weapon of the Gatling-gun type and a lubricating device actuated in response to the rapid vibrating motion of the internal gun mechanism.

Summary of the invention In the disclosed embodiment the invention comprises a lubricator having a housing or reservoir casing adapted to contain lubricant, an inner support member, pick-up and delivery lines for oil contained within the housing, a pump chamber in flow relationship with the lines, a piston within the chamber having an elongated actuator rod, and a mass or weight retained on the rod at the opposite end of the piston externally of the reservoir. The lubricator is utilized with a high rate of fire automatic weapon operating on the Gatling-gun principle and having a plu- 3,391,602 Patented July 9, 1968 "ice Other objects and advantages of our invention will become more evident from the claims appended hereto, when read in the light of the following detailed description with the accompanying drawings in which:

FIG. 1 is an external view of a rapid-fire weapon of the Gatling-gun type with lubricator mounted thereon, illustrating the overall gun and the external lubricator configuration and delivery line location;

FIG. 2 is an end view of the gun and lubricator assembly of FIG. 1, illustrating the lubricant feed line to the FIG. 3 is a cross-sectional view of a preferred embodiment of the lubricator; and

FIG. 4 is a graph illustrating the output flow of lubricant during a typical gun burst period.

Description of the preferred embodiment As seen in FIGS. 1 and 2 the automatic weapon comprises a plurality of barrels 10 mounted on a rotor body 12 rotatably supported in a gun housing indicated generally at 14. The gun is adapted to be supported by means (not shown) carried on a vehicle which may be an aircraft, tank, personnel carrier, or the like, depending on the tactical mission for which the weapon is designed. In any event, the rotor 15 revolves about the gun axis when driven by suitable external or internal power means (not shown). As seen in FIG. 2, the gun has a plurality of bolts, one of which is partially shown at 16. The bolts ride in tracks or ways 18 machined in the rotor body periphery. As stated above, a more complete description of the gun mechanism may be found in the patent to Otto 2,849,921. It will sufiice for describing our invention to say that the bolts reciprocate rapidly in the cam tracks as the gun is operated at firing rates up to and exceeding 6000 shots per minute (s.p.m.), depending on the size of the weapon. This very high rate of fire which is unique to the modern day Gatling-gun results in a substantially steady vibration of the overall gun. The vibration typically has a specified amplitude and driving frequency rate depending on the rate of fire of the gun. The systems driving frequency can be ascertained therefor for any given gun and associated equipment. We have taken advantage of this phenomenon to combine with the gun a frequency responsive system in the form of a lubricator pump mechanism. That is, the lubricator, which is indicated generally at 30 in the drawings, fimctions, in part, as a vibration actuated mass-spring system.

Turning to FIG. 3 for a description of the lubricator in detail, it will be seen to include an outer casing or housing 32 which forms a reservoir for the lubricant (oil or grease), indicated generally at 34. The outer casing is sealed, at 36, to a mounting flange 38 adapted to be suitably fastened at 39 to a gun housing flange, indicated at 1411. Supported within the reservoir by suitable means, such as bolts ill-40, is an internal support assembly or frame indicated generally at 42. The frame 42, in turn, supports an intake lube line 44 having a downwardly opening pick-up orifice 44a, an internal delivery line 46 connected to an exit fitting 48 fastened in an opening 49 in flange 38, and a pump assembly indicated generally at 50. The pump assembly is a hollow body having an upright (in the diawing) intake portion 52, a piston chamber portion 54 extending perpendicular to the intake portion 52 and in flow communication therewith, and an exit or delivery portion 56. The pump intake section 52 is connected through fitting 52a to intake line 44, while the pump exit section 56 is connected through a fitting 56a to the internal delivery line 46. Fittings 52a and 56a are threaded or otherwise securely fastened intermediate lines 44 and 46, respectively, and the pump assembly and effectively support the pump assembly on frame 42 by projecting through holes in the supporting frame, as is indicated at 58 and 60 on the frame. Obviously, other means of supporting the lines and the pump assembly will occur to those skilled in the art, and the configuration shown is for purpose of illustration only.

The pump assembly 50 will now be described in more detail. As seen in FIG. 3, the intake passage 60 contains a one-way flow restrictor, in this case a typical ball-check valve arrangement indicated generally at 62. Lubricant flow passes through orifice 62a, therefore, in one direction only, i.e., downward (in the drawing) and into the piston chamber interior 54a. A hollow piston sleeve 64 connected to one end at 65 to a piston or actuator rod 66 is operable against a spring 68 contained by the sleeve 64 and bottoming on the pump chamber far wall, at 69. The rod 66 projects through an opening in the end of wall of the chamher, at 70, the pump wall being held in location against the frame 42 by suitable means such as a threaded bushing 72. At the opposite end of the housing 32 from flange 38 is an enlarged pad 74 projecting inwardly of the reservoir. Pad 74 has a central opening 76 into which is fitted cylindrical bearing means 78. The bearing means supports rod 66 which extends through the pad opening and a smaller aligned opening at 80 in the casing wall. A suitable sealing member 82 closes opening 76 to lubricant How. The other end of the actuator rod 66 projects substantially beyond the reservoir, being received in a cover portion 84 of the lubricator housing. The cover encloses a mass or actuator weight 86 securely fastened by suitable means, such as nut 89 to the end of the rod. The exit or delivery portion 56 also includes a one-way ball check type valve assembly, indicated generally at 90, for purposes now to be described.

In operation, it will be assumed that the gun shown has C a normal maximum firing rate of approximately 6000 s.p.m. A typical driving frequency for a gun of a given weight was therefore found to be about 100 c.p.s. at an acceleration rate on the order of 70 Gs. The lubricator 30 was therefore designed to take advantage of this phenomenon, as stated above, by providing that the pump assembly piston, piston rod, and weight 86, together with spring 68, function as a vibrating mass-spring system. This is in contrast to the conventional inertia system which would utilize a full displacement of the piston which would occur at the beginning of weapon operation and at shut-off, in a weapon of the type shown in the aforementioned Otto patent. Thus, we have provided a gun lubricating system wherein a continuous and sustained supply of lubricant is provided as the gun operates.

To explain in more detail, as the weapon vibrates the piston moves back and forth in the chamber 54a in response to the effect of the vibration on the weight or mass 86. On the intake stroke (movement to the left in the drawing) valve 62 opens and the chamber 54a fills. On the delivery (opposite movement) stroke, valve 62 closes and valve 90 opens to deliver lubricant. It was also discovered that the pump assembly piston action can operate as a damper on the vibrating mass-spring mechanism described above due to the fact chamber 54a is filled with lubricant which is being moved. Orifices 62a and 90a can be adjusted to regulate this as can the mass-weight 86-be also conveniently adjusted to give a maximum level of continuous and regular displacement of the pump piston at a particular driving frequency using the relationship:

where,

X =maximum piston rod displacement F=force, tag, 70 G acceleration level acting on the mass K=the spring gradient (e.g., spring 68) u=a magnification factor which is a function of the ratio of the vibration (driving) frequency (V to the natural frequency of the mass-spring system (W and the damping ratio (P), or

In one case, the maximum piston displacement for a weight of 0.6 pound was found to be .06 inch, where the gun vibration or driving frequency was c.p.s. at the 70 G acceleration level or 0.25 inch, as seen in the graph of FIG. 4. The magnification factor (a), on the other hand, is limited in effect for damping ratios on the order of 1 or greater. In the apparatus of our invention damping ratios are selected to be 1 or greater and, further, the damping ratio will increase with increased viscous damping, i.e., lower lubricant temperatures. Thus, for a typical firing burst, such as is shown pictorally in FIG. 4, lubricant is delivered to the gun bolt tracks on a sustained basis, rather than periodically at starting and stopping of the weapon operation.

While other machines having the vibratory motion pecular to the apparatus shown herein could also utilize our lubricating system, it has been found to be quite effective for weapons of the Gatling-gun variety. Such weapons can have a vibratory range of approximately 20-200 c.p.s., in which case the piston mass or weight could vary from .0 to 2.0 pounds. In such cases, the spring gradient, of the mass-spring system, could range from 1 pound/ inch to 50 pounds/ inches.

The frequency responsive gun lubricating system of our invention, as described above, has been shown to have substantial advantages in operating reliability over the more complex cam and lever operated inertia systems. It will be understood, however, that the claims appended hereto are intended to cover obvious modifications and changes in the lubricator design and in the mass-spring pump mechanism herein illustrated as will occur to those skilled in the art.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. Frequency responsive lubricator apparatus for a high rate of fire automatic weapon having a plurality of barrels radially grouped for rotation about a common axis and a plurality of bolt assemblies longitudinally movable parallel to said axis and rotatable with said barrel group, said Weapon having a vibration-generated operating frequency, said lubricator apparatus comprising:

a lubricant reservoir adapted to be aflixed to the automatic weapon;

conduits in flow communication with said reservoir for pick-up and delivery, respectively, of lubricant to said weapon;

and pump means interconnecting said pick-up and delivery conduits, said pump means including a massspring mechanism operable in response to the vibration-generated operating frequency to cause said pump means to provide a continuous, regular amount of lubricant to said weapon during its operating period.

2. The apparatus of the invention according to claim 1 wherein said pump means includes an intake section connected to the pick-up conduit, a first check valve inv said intake section, a delivery section connected to the delivery conduit, 21 second check valve in said delivery section, and a piston chamber intermediate said intake and said delivery sections, and wherein said mass-spring mechanism includes a hollow piston member reciprocally movable in said chamber, a spring partially enclosed by said piston and bottoming on a chamber well, an elongated actuator rod attached at one end to the piston and projecting axially therefrom externally of said reservoir, and a mass of predetermined weight affixed to the other end of said actuator rod.

3. In combination: an automatic weapon, said weapon having a rotor, a housing supporting said rotor for rotation about its longitudinal axis, a plurality of barrels mounted on said rotor in a radial grouping about said axis, a plurality of bolt assemblies reciprocally movable in axial tracks on the periphery of said rotor, and means to power said rotor during weapon operation to discharge cartridges alternately and sequentially through said barrels, said weapon operation generating a vibratory frequency dependent on the speed of rotation of said rotor; and lubricator apparatus afiixed to said weapon housing,

said apparatus comprising,

a lubricant reservoir,

an intake conduit within said reservoir having a pick-up opening immersed in the lubricant,

a delivery conduit, said delivery conduit operatively connecting said reservoir to the rotor tracks,

pump means interconnecting said conduits within said reservoir, said pump means including a lubricant chamber, a first check valve on the intake side of the chamber, and a second check valve on the delivery side of the chamber, and

a mechanism operable to cause sequential opening and closing of said first valve for charging said chamber with lubricant and sequential closing and opening of said second valve for discharging said chamber, said mechanisrn comprising a hollow piston slidingly received in said chamber, an axially-extending actuator rod attached at one end to said piston, said rod projecting outwardly of said reservoir through an end wall of said chamber, a spring partially enclosed by said piston and bottoming on a wall of said chamber opposite said end Wall, and 'a weight affixed to the other end of said actuator rod,

said piston, said rod and said weight together with said spring comprising a mass-spring system responsive to the operating vibratory frequency of said weapon to cause lubricant to be pumped thereto.

4. The invention of the apparatus according to claim 3 wherein the weight of said mass-spring system has an approximate range of 0.1 to 2.0 pounds and said spring has an approximate gradient range of 1.0 pound/ inch to 50 pounds/inches.

References Cited UNITED STATES PATENTS 1,351,017 8/1920 Blackmore 891.2 2,849,921 9/1958 Otto 8912 SAMUEL W. ENGLE, Primary Examiner.

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