US3461589A - Firearm recoil reducer with an inertia member having valve means therein - Google Patents

Description

A l. D. VIRONDA Aug. 19, 1969 FIRE/mm REcoIL REDUCER WITH AN INERTIA 3,461,589

MEMBER HAVING VALVE MEANS THEREIN Filed Sept. 20, 1968 United States Patent O 3,461,589 FIREARM RECOIL REDUCER WITH AN INERTIA MEMBER HAVING VALVE MEANS THEREIN Italo D. Vronda, 194 N. Wabash, Battle Creek, Mich. 49017 Continuation-impart of application Ser. No. 706,021, Feb. 16, 1968. This application Sept. 20, 1968, Ser. No. 761,269

Int. Cl. F41c 23/00 U.S. Cl. 42-74 9 Claims ABSTRACT OF THE DISCLOSURE A recoil mechanism for a firearm having a sleeve xedly positioned within the stock of the firearm and -an inertia member slideably positioned within the sleeve, and maintained within one end thereof by a releasable holding means, such as a magnet. The recoil forces, which cause the sleeve to move relative to the inertia member, overcome the releasable holding force between the inertia member and the sleeve, thereby resulting in the absorption of a substantially large recoil force. Spring means bias the inertia member back into engagement with the sleeve to re-establish the releasable engagement therebetween. The inertia member further includes a passageway in communication with the sleeve adjacent opposite ends of the inertia member, which passageway contains a one-way check valve therein. The check valve prevents flow of air therethrough as the inertia member is moved during firing while permitting air to freely pass therethrough during return movement of the inertia member toward its original position.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my prior copending application Serial No. 706,021, entitled, Recoil Mechanism for Guns, filed Feb. 16, 1968.

FIELD OF THE INVENTION This invention relates in general to firearms and, more particularly, to a mechanism for reducing recoil upon firing.

BACKGROUND OF THE INVENTION In the tiring of firearms, particularly rifles and Shotguns, the development of recoil has long been accepted as an unpleasant but unavoidable condition. Numerous efforts have been undertaken heretofore to bring about reductions if not elimination of such recoil. However, none of these efforts have sufficiently solved the problem so that sports enthusiasts, soldiers, and the like, must expect the shock of recoil upon tiring a riiie, shotgun, or the like. Such recoil results often in physical discomfort to the user, which may, in addition to entailing painful bruises, bring about a numbing of the shoulder area.

Furthermore, recoil also is productive of substantial inaccuracy in tiring since the force thereof may contribute to the firearm being inadvertantly raised or caused to jump in addition to the fact that the individual user may expectedly be diverted from full control of the firearm in anticipation of the impact of recoil.

While various recoil devices have been developed and utilized on rearms, such as rifles and Shotguns, none of these devices, to my knowledge, have been successful in eliminating a substantial portion of the recoil forces transferred to the shoulder of the user during firing of the firearm. Most of the prior recoil devices have utilized a hollow housing member fixedly connected to the firearm with the housing having a plunger or inertia member slideably mounted therein, resilient means, such as coil rice springs, being provided between the plunger and the housing to absorb the recoil energy as relative movement occurs therebetween during firing. In these devices, however, the amount of recoil force absorbed is substantially directly proportional to the relative movement between the housing `and the plunger, which movement results in a compression of the coil spring. Since the coil springs generally have a linear spring rate, and further since the springs utilized in these devices are relatively small, a small relative movement between the firearm and the plunger is effective in developing only a relatively small force on the spring and thus only a very small portion of the recoil force is effectively absorbed by these devices. While these devices would be capable of absorbing a greater portion of the recoil force if a1- lowed to undergo a substantial amount of relative movement, this is not physically possible since the butt of the rifie is generally held tightly against the shoulder of the user `and thus most of the recoil forces are transferred into the shoulder rather than being absorbed by the recoil device.

The recoil device disclosed in my copending application Ser. No. 706,021 has proven highly successful in substantially eliminating or minimizing firearm recoil and its attendant undesirable effects. However, it has been discovered that the inertia member does not always return to its initial position as rapidly as desired, this return movement of the inertia member being especially critical when the recoil mechanism is mounted on an automatic type of firearm capable of repeatedly firing a large number of shots within a very short time interval.

Accordingly, it is an object of the present invention to provide:

(l) A recoil mechanism adapted for disposition in a firearm, such as a rifle or shotgun, for substantially eliminating recoil with its attendant undesirable effects.

(2) A recoil mechanism, as aforesaid, having an inertia member movably mounted on the firearm and capable of absorbing a substantially large portion of the recoil force or energy by only a small relative movement between the firearm and the inertia member.

(3) A recoil mechanism, as aforesaid, having means for permitting the inertia member to quickly return to its original position after firing so as to permit the rearm to repeatedly fire a large number of shots within a short time interval.

(4) A recoil mechanism, as aforesaid, having releasable holding means for holding the inertia member stationary relative to the firearm and for imposing a predetermined holding force thereon, the holding force being overcome during recoil whereby a substantial portion of the recoil force is absorbed due to a small movement of the inertia member relative to the firearm.

(5) A recoil mechanism, as aforesaid, wherein the releasable holding means comprises a magnet for holding the inertia member stationary relative to the firearm with the magnetic force being overcome during recoil 'whereby a substantial portion of the recoil force is absorbed.

(6) A recoil mechanism, as aforesaid, wherein the inertia member has a passage extending therethrough containing a one-way check valve therein for preventing iiow of air through the passage when the inertia member moves forward during firing of the firearm, said valve causing compression of the air ahead of the inertia member so as to further absorb the recoil force and permit the inertia member to be quickly returned to its original position.

(7) A recoil mechanism, as aforesaid, wherein the one-way check valve freely permits any air trapped between the inertia member and the magnet to be easily vented through the check valve during the return movement of the inertia member.

(18) A recoil mechanism, as aforesaid, adapted for easy reception within the stock of a rifle, shotgun, or similar firearm without necessitating costly modification thereof or reduction of effective operation of same.

(9) A recoil mechanism, as aforesaid, which may constitute an accessory for mounting within existing firearms, or may be incorporated into Same as a part of the original equipment thereof.

(l) A recoil mechanism, as aforesaid, which is totally enclosed to prevent entry thereinto of moisture and other contaminating materials.

(11) A recoil mechanism, as aforesaid, which is economically produced, is extremely durable and reliable in usage, is installable into existing firearms by the owner thereof without resort to the services of trained individuals, such as gunsmiths, and is of great simplicity in construction and operation.

Other objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a longitudinal cross-sectional view of the recoil mechanism constituting the present invention.

FIGURE 2 is a cross-sectional View taken along the line II-II of FIGURE l.

FIGURE 3 is a cross-sectional View taken along the line III-III of FIGURE 1.

FIGURE 4 is a fragmentary longitudinal view in partial vertical section showing the breech and stock portions of a rifle or shotgun incorporating therein a recoil mechanism constructed in accordance with and embodying the present invention.

Certain terminology will be used in the following description for convenience and reference only and will not be limiting. The words upwardly, downwardly, rightwardly and leftwardly will designate directions in the drawings to which reference is made. The word forwardly will refer to the normal direction of travel of the firearm projectile and the word rearwardly will refer to the opposite direction, that is, the normal direction of travel of the firearm as caused by the recoil forces. The words inwardly and outwardly will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Such terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.

SUMMARY OF THE INVENTION In general, the objects and'purposes of the invention are met by providing a recoil device which is positioned within an opening or compartment preferably formed in the stock of a firearm. The recoil device includes a hollow sleeve which is tixedly positioned relative to the firearm stock with an inertia member being slideably mounted within the sleeve. The opposite ends of the sleeve are closed by end walls fixedly secured thereto, the end Wall positioned adjacent the back of the firearm having releasable holding means, preferably a magnet, fixedly secured thereto whereby the inertia member, being of a magnetic material, is attracted to the magnet and is normally held in engagement therewith. A spring is provided between the other end of the inertia member and the other end of the sleeve for resiliently urging the inertia member toward and against the magnet. A passageway extends through the inertia member for communicating with opposite ends of the sleeve, which passageway contains a one-way valve therein for preventing fiow of air therethrough from the said other end 0f the sleeve. When the firearm is fired, the recoil forces cause the stock of the rearm and the sleeve of the recoil mechanism to be 4 moved rearwardly, during which movement the inertia member tends to remain stationary since it is freely Slideably positioned within the sleeve. Since the recoil is generally substantially larger than the magnetic force of attraction developed in the recoil device, the rearward movement of the sleeve by the recoil forces will be sufficient to overcome the magnetic force of attraction between the magnet and the inertia member whereupon the inertia member will become separated and displaced from the magnet. The portion of the recoil force required to overcome the magnetic attraction in thus absorbed within the recoil device and is not transferred to the shoulder of the used. Additional recoil force is absorbed due to compression of the spring by the inertia member and by compression of the air trapped within the end of the sleeve by the one-way check valve as the sleeve continues to move rearwardly. However, a substantially large portion of the recoil forces are almost instantaneously and initially absorbed since only a small relative movement between the inertia member and the stock is necessary to separate the magnet and the inertia member and thus only a small relative movement between the inertia member and the magnet must overcome the full magnetic force. The spring and the compressed air permit the inertia member to be rapidly returned to its initial position, the one-way check valve permitting any air trapped within the sleeve adjacent the magnet to be readily vented therethrough so as to not impede the return movement of the inertia member.

DETAILED DESCRIPTION FIGURES 1-3 illustrate a preferred embodiment of the present invention, wherein there is illustrated a recoil mechanism indicated generally by the reference numeral 10. The recoil mechanism includes an outer housing member preferably constructed of light meta-l in the form of a cylindrical sleeve 11 having a substantially cylindrical opening 12 extending throughout the length thereof. The forward end of the sleeve 11 is closed by means of an end wall 13 integrally connected thereto. The rearward end of the sleeve 11 is similarly closed by means of a cap 14 which is fixedly connected to the sleeve by any suitable fastening means, such as a pair of lock pins 16 extending transversely through the cap 14 and the sleeve 11. A resilient O-ring seal 15 is preferably provided between the cap 14 and sleeve 11. The inner end of the cap is provided with a counterbore or recess 17 in which a magnet 18 is fixedly secured, as by a rivet 20, the magnet having a surface 19 facing inwardly into the opening contained within the sleeve 11. The sleeve 11 is preferably constructed of a nonmagnetic material, such as aluminum or brass, while the cap 14 may be constructed either of a ferrous or nonferrous material.

Slideably positioned within the opening 12 between the end wall 13 and the magnet 1S is an inertia member 21, which member is constructed generally in the form of a cylindrical plunger member and is 0f a magnetic material so as to be magnetically attracted by the magnet 18. The inertia member 21 comprises a main body portion 22, preferably of cylindrical configuration, which portion is preferably provided with a boss portion 30' integrally connected thereto and extending axially therefrom as illustrated in FIGURE l, said boss portion 30 having a transverse end face 23 confronting and being adapted to contact the surface 19 of the magnet 18 when the inertia member 21 is held in contact with the magnet 18.

The boss portion 30 is of smaller diameter than the main body portion 22 and is slideably received within the recess 17 formed within the cap 14, the outer periphery of the boss portion 30 being slightly smaller than the inner periphery of the recess 17 whereby a small annular clearance space exists therebetween for a purpose to be explained hereinafter. The boss portion 30 has a small annular recess 24 formed in the periphery thereof adjacent the end face 23, a compression ring 26, preferably of a durable resilient material such as Tellon, being positioned within the recess 2'4 so as to slideably engage the inner periphery of the recess 17. The cornpression ring 26 is split, as illustrated in FIGURE 3, thereby forming a slot 25 between the ends thereof. A further ring 40, preferably a resilient O-ring, is mounted on and surrounds the boss portion 30 adjacent the end of the main body portion 22, the ring 40 acting as a buffer or resilient stop for the plunger.

The other end of the main body portion 22 is preferably provided with a further boss portion 27 integrally interconnected thereto and extending axially therefrom as illustrated in FIGURE 1. The boss portion 27 is of a smaller diameter than the main body portion 22 and functions as a seat and guide for one end of the compression spring 28 positioned within the opening 12. The other end of the spring 28, which spring may be of a very low stiffness, bears against a resilient or llexible disk 31 positioned adjacent to and in contact with the end Wall 13. The disk 31 is preferably made of leather or other suitable exible or resilient materials s0 as to permit partial absorption of the rebound energy of the inertia member.

The boss portion 27 of the inertia member 21 is preferably provided with an undercut groove 32 therein at the junction between the boss portion 27 and the main body portion 22, which undercut groove permits the end coil of the spring 28 to be positioned therein so as to retain the spring in engagement with the inertia member 21. The leading edge of the boss portion 27 is preferably bevelled as illustrated in FIGURE 1 so as to facilitate relative movement between the spring 28 and the inertia member 21.

The inertia member 21 is further provided with an elongated axial passage 34 extending partially therethrough, the passage 34 extending through the boss portion 27, the main body portion 22 and partially through the boss Portion 30, terminating short of the end face 23. A transverse passageway 36 is positioned adjacent the innermost end of the axial passage 34 with the opposite ends of the transverse passage 36 opening into the annular clearance space between the periphery of the boss portion 30 and the inner periphery of the recess 17. The passages 34 and 36 thus permit communication between the one end of the opening 12 (rightward end in FIGURE 1) and the clearance space surrounding the boss portion 30. Similarly, the annularclearance space surrounding the boss portion 30 communicates through the slot 25 formed in the split compression ring 26 with the space between the faces 19 and 23 when the inertia member 21 is positioned out of engagement with the magnet 18.

The end of the passage 34 is provided with an enlarged counterbored portion 38 in which is positioned a valve means, indicated generally at 39. The valve means 39 comprises a one-way check valve having a ball member 41 positioned within and movable relative to a seat member 42 and an opposed stop 43. The seat member 42 is ixedly positioned within the enlarged bore 38 and is provided with a passageway 44 therethrough which has a substantially conical valve seat 46 provided thereon adapted to be abuttingly contacted by the ball valve member 41. The otherend of the seat member 42 is provided with threads thereon for permitting the stop 43 to be threadably engaged therein, which stop is further provided with a passage 47 extending therethrough so as to communicate with the opening 12 contained within the sleeve 11, which opening contains therein the spring 28. The stop 43 is provided with a shoulder 48 thereon for retaining the ball valve member Within the seat member `42. However, the shoulder 48 is spaced from the conical seat 46 by a sufficient distance so as to permit the ball valve member 41 to have limited movement axially of the inertia member whereby the ball member can freely move between open and closed positions wherein the ball member is out of and in sealing engagement with, respectively, the conical seat 46.

The magnet 18, in cooperation with the magnetic material of the inertia member 21, functions as a releasable holding means capable of developing a predetermined holding force for maintaining the inertia member in engagement within the rearward end of the housing, which holding force decreases in a nonlinear manner as the inertia member moves relative to the housing, thereby absorbing a substantial portion of the recoil force.

OPERATION The operation of the device embodying the invention will be described in detail hereinbelow for a better understanding of the invention.

In usage, the recoil mechanism 10 illustrated in FIG- URE 1, is mounted on or positioned within arearm 51, such as is schematically illustrated in FIGURE 4. The normally wooden stock 52 of the firearm 51 is provided with an opening 53 therein, which opening is substantially axially parallel to the barrel 54 of the firearm 51. The opening 53 generally has a cylindrical configuration whereby the sleeve 11 will be receivable therein. The opening 53 is preferably formed as a blind bore so as to form a front face 56, with the forward end wall 13 of the sleeve 11 being positioned adjacent thereto. A resilient buffer 57 is preferably positioned between the end wall 13 and the front face 56 to prevent the imposition of large impact loads on the wooden stock. The rearward end of the opening 53 is closed by means of a butt plate 58 secured to the Stock 52 by means of screws 59. When the recoil mechanism 10 is positioned in the opening 53 and the butt plate 58 is xedly secured to the stock 52, the end plate 14 of the recoil mechanism preferably bears against the butt plate 58 so as to prevent any axial movement of the sleeve 11 relative to the lirearm 51. However, since the axial length of the opening 53 may substantially exceed the length of the sleeve 11, a plurality of resilient spacers 61 may be positioned between the end plate 14 and the butt plate 58 to prevent any axial movement of the sleeve within the opening. Further, if the sleeve 11 is of substantially smaller diameter than the opening 53, any suitable means can be used so as to cause the sleeve 11 to be snugly held within the opening 53, such as by wrapping the sleeve 11 with tape.

With the recoil mechanism 10 thus installed within the stock 52 of the firearm 51, the user is free to lire the rearm 51 with a sense of assurance that the theretofore experienced powerful recoil will be substantially minimized or eliminated.

Before the firearm is lired, the recoil mechanism will be positioned substantially as illustrated in FIGURE 1, that is, the inertia member 21 will be positioned by the spring 28 adjacent the rearward end of the firearm and held in abutting engagement with the exposed face 19 of the magnet 18 by the magnetic force of attraction existing between the two abutting members. When the rie or shotgun is tired, the recoil forces will be imposed on, and transferred rearwardly through, the stock 52 so as to tend to move the firearm rearwardly against the shoulder of the user. The sleeve 11 of the recoil ,mechanism 10, being iixedly held relative to the stock caused thereby will tend to cause the sleeve 11 to move rearwardly in an axial direction relative to the inertia member 21 so as to cause relative axial movement to occur therebetween.

In order for the sleeve 11 and the magnet 18 ixedly 7 secured thereto to move axially rearwardly relative to the inertia member 21, it is first necessary for the recoil forces to overcome the holding force or magnetic force of attraction which exists between the magnet 18 and the inertia member 21. Since the recoil forces are generally substantially larger than the magnetic force of attraction, the recoil force will be sufiicient to accomplish this and thereby cause the sleeve 11 and the magnet 18 to move axially rearwardly relative to and away from the inertia member 21. However, in overcoming this magnetic force of attraction, a portion of the recoil force is thus absorbed by the recoil mechanism and is thus not transferred to the shoulder of the user of the firearm. Further, this portion of the recoil force is absorbed almost instantaneously upon firing since the magnetic holding force decreases in a nonlinear exponential manner, that is, the magnetic force of attraction decreases inversely in proportion to the square of the distance separating the magnetic members. Thus, only a small relative axial movement is needed to overcome a substantial portion of the magnetic holding force.

After the magnetic force of attraction has been overcome, still further absorption of the recoil forces is obtained since additional relative axial movement between the inertia member 21 and the sleeve 11 causes the compression spring 28 to be compressed between the end wall 13 and the hub portion 27, which force of compression is substantially directly proportional to the amount of compression of the spring.

During the above-described recoil movement, whereupon the inertia member 21 is relatively moved away from the member 18 in a direction toward the end 13 of the sleeve, the ball member 41 is moved relative to the inertia member 21 in a direction toward the conical seat `46 whereupon the ball valve member 41 tends to close the passageway 44 so as to prevent the fiow of air therethrough. The air enclosed within the opening 12 in surrounding relationship to the coil spring 28 is thus trapped and is compressed as the inertia member 21 moves in a direction toward the end wall 13. This compression of the air within the sleeve causes the pressure of the air to be increased, which in turn acts against the ball valve member 41 and tends to maintain same in tight sealing engagement with the Valve seat 46. The trapped air thus substantially functions as an air spring and permits the further absorption of recoil forces.

After the recoil forces have been absorbed by the device and the inertia member has come to a stop at a forwardmost position displaced axially from the magnet 18, the spring 28 urges the inertia member 21 in the opposite direction (leftwardly in FIGURE 1) so as to return same to its initial position directly adjacent and in contact with the magnet 18. During the return movement of the inertia member, any air which is entrapped between the magnet 18 and the adjacent end face 23 of the inertia member is permitted to escape by passing through the slot 25 formed in the compression ring 26 and through the annular clearance space between the boss portion 30 and the inner periphery of the recess 17. The air then fiows through the passageways 36 and 34 and through the one-way valve 39 into the sleeve opening 12 in surrounding relationship to the coil spring 28. The one-way valve 39 freely opens to permit any trapped air to pass therethrough whereupon the inertia member is quickly returned by means of the spring 28 to its initial position.

When the inertia member 21 has come to a stop at its forwardmost position displaced axially from the magnet 18, the air trapped within the end of the sleeve 11 in surrounding relationship to the spring 28 is at its maximum level of compression and thus this highly compressed air further assists in stopping the forward movement of the inertia member and initiating the return movement of the inertia member toward its original position. Further, when the inertia member is at this forwardmost position, a Substantially large space exists between the other end of the inertia member and the magnet 18, whereupon any air entrapped within this space is at a low pressure level. As the inertia member returns toward its original position, the pressure of the air Within the sleeve adjacent the end wall 13 thus rapidly decreases while the pressure of the entrapped air adjacent the magnet 18 rapidly increases, whereupon the ball valve 41 is moved by the entrapped pressurized air into the open position so as to permit the entrapped air to flow through the axial passageway 34 into the other end of the sleeve in surrounding relationship to the spring 28.

The one-way check valve 39 has proven very successful in permitting the inertia member 211 to be rapidly returned to its initial position so as to permit same to successfully operate when the firearm is repeatedly and rapidly fired. This rapid and successive seating of the inertia member in its initial position is made possible by the one-way check valve 39 maintaining the 4axial passageway 34 closed during the forward movement of the inertia member and thus preventing air from freely entering into the chamber between the inertia member 21 and the magnet 18, the presence of which greatly restricts the return movement of the inertia member toward its initial position. `On the other hand, the one-way valve 39 does freely open on the return movement so as to permit any air accidentally trapped between the inertia member `and the magnet to freely escape.

In view of the foregoing, it will be seen that a recoil mechanism constructed in accordance with the present invention may be readily installed in an existing type of firearm without requiring the skilled services of a gunsmith, but may be readily installed by the average firearm user without costly modification of the particular firearm. Furthenmore, as is evident from the foregoing, the recoil mechanism hereinabove described will permit comfortable, consistently accurate and reliable usage of substantially powerful firearms obviating the various attendant unpleasant effects of the recoil which currently had been considered as unavoidable conditions of firearm usage.

It will also be obvious that, in the recoil mechanism described above, the magnet 18 used for holding inertia member 21 stationary relative to the sleeve 11 can be positioned either on the sleeve or on the inertia member, 'as desired. Still further, a pair of lmagnets could be utilized with one of the magnets being mounted on the sleeve and the other of the magnets being mounted on the inertia member if so desired. While all of the recoil mechanisms illustrated and discussed above have been of a cylindrical configuration, it will be recognized that this configuration is utilized merely for convenience in manufacture yand installation and any other desired crosssectional configuration can obviously be utilized.

The recoil mechanism illustrated in FIGURES 1-3 is preferred since same is substantially and completely enclosed, the outer sleeve 11 not having any vents or openings passing therethrough. This is advantageous since such 'a closed construction thus prevents moisture or other contaminating material from entering into the interior of the recoil mechanism, whereupon the recoil mechanism will thus not be susceptible to rust or fouling. Such a recoil mechanism thus possesses durability and dependability of operation and will require very little maintenance and/or repair.

'I'he inerti-a member 21 used in the recoil mechanism is preferably constructed of a magnetic or ferrous material. However, it will be obvious that only the axial end portion of the inertia member 21 adjacent the end face 23 need be of a magnetic material so as to be magnetically attracted by the magnet 18. The remainder of the plunger 21 could, if desired, be of a nonmagnetic material.

While the releasable holding means used in the recoil mechanism of the present invention has been disclosed as preferably comprising a magnet, other suitable holding devices could be utilized. Such holding means must be able to develop a predetermined or threshold holding force between the inertia member and the housing with the holding force being overcome by a small relative movement therebetween. lFor example, the end cap 14 and the adjacent end of the inertia member 21 could be formed with a mechanical snap-like connection therebetween. Alternatively, sleeve 11 could have a springbiased detent mounted thereon and engageable with the inertia member 21 for holding same, the detent disengaging the inertia member and permitting same to move relative to the sleeve when subjected to an axial force of predetermined magnitude. Accordingly, the present invention encompasses not only the holding means disclosed above, but also other holding devices which function in a substantially similar manner. K

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A recoil mechanism to be mounted on a lirearm for absorbing at least a portion of the recoil energy, said mechanism comprising:

housing means adapted to be iixedly mounted on said firearm, said housing means having an opening therethrough and wall means yat least partially closing opposite ends of said opening; inertia member means mounted Within said opening for movement relative to said housing; releasable holding means creating a holding force for releasably holding said inertia member means in a normal position substantially adjacent said wall means at one end of said opening, the recoil energy upon tiring tending to overcome the holding force so as to move said inertia member means in a direction toward the other end of said opening; passageway means interconnecting the portions of said opening adjacent the opposite ends of said inertia member means for permitting fluid communication therebetween; and one-way valve means positioned within said pasageway means for permitting fluid flow through said passageway means in a direction from said one end of said opening toward the said other end of said opening, said one-way valve means preventing Huid flow in the reverse direction. 2. A recoil mechanism as defined in claim 1, wherein: said holding means develops a holding force of a predetermined magnitude when said inertia member is maintained in s'aid normal position substantially adjacent said wall means, said holding force decreasing below said predetermined magnitude as said inertia member moves away from said normal position. 3. A recoil mechanism as defined in claim 1, wherein: said holding means includes magnet means creating a magnetic holding force for maintaining said inertia member in said normal position. 4. A recoil mechanism as defined in claim 3, wherein: said Wall means including a cap member xedly secured to said housing adjacent said one end of said open- 111g; said magnet means including a magnet fxedly secured to said cap member and at least a portion of said inertia member means being of a magnetic material so as to be magnetically attracted to Said magnet whereby said inertia member means is normally maintained in a position substantially adjacent said magnet.

5. A recoil mechanism as defined in claim 3, wherein:

said housing means comprises a substantially cylindrical sleeve with said opening extending substantially longitudinally throughout the length of said sleeve;

said wall means including a first end wall member ixedly secured to said'sleeve adjacent said one end of said opening and -a second end wall member fixedly secured to said sleeve adjacent the other end of said opening;

said inertia member means including a substantially cylindrical plunger slidably positioned within said opening for slideable movement relative to said sleeve, said plunger being normally positioned within said opening adjacent said one end thereof whereby one end of said plunger is positioned closely adjacent to said first end wall member; and

spring means positioned within said opening between said second end wall member and the other end of said plunger for resiliently urging said plunger toward said normal position.

6. A recoil mechanism as defined in claim 5, wherein:

said passageway means interconnecting portions of said opening adjacent opposite ends of said plunger including a passage formed in said plunger and extending axially thereof; and

said one-way valve means comprising 'a ball-type check valve positioned within said passage for preventing ow of fluid therethrough in a direction from said other end of said opening toward said one end of said opening.

7. A recoil mechanism as deiined in claim 6, wherein:

said passageway means further includes a second passageway extending radially of said plunger and in communication with said first-mentioned passageway and a third passageway interconnecting said second passageway to said one end of said opening.

8. A recoil mechanism as defined in claim 7, wherein:

said third passageway is defined by a clearance space existing between said plunger and said housing means.

9. A recoil mechanism as defined in claim 1, wherein:

said passageway means includes a passageway formed in said inertia member means and extending axially thereof; and

said one-way valve means being mounted on said inertia member means and positioned within said passageway.

References Cited UNITED STATES PATENTS 3,176,424 4/ 1965 Hoge 42-74 3,290,815 12/ 1966 Edwards 42-74 3,300,889 1/ 1967 Baker 42-74 3,365,829 1/1968 Shockey 42--1 3,381,405 5/ 1968 Edwards 42-74 3,405,470 10/1968 Wesemann 42--74 3,408,062 10/1968 Baker 42--74 BENJAMIN A. BORCHELT, Primary Examiner

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