Patent Application
20250020437
A quick-attachment/quick-release firearm accessory mounting assembly is disclosed herein. The mounting assembly is releasably and rotatably attached to a firearm rail, chassis, or handgun slide to receive any of a number of different accessories, such as, for example, a telescopic sight, reflector sight, laser sight, night vision sight, thermal scope, range finder, and other secondary instruments. The mounting assembly is in the form of an adaptor plate or platform having attachment structures for receiving the accessory on a top surface, and securing to the firearm structure on a bottom surface. In an exemplary embodiment, a pistol slide top surface is modified to receive an adaptor plate. Traditionally, these accessories are attached directly to a mounting structure on the firearm, such as a scope mount or rail.
Numerous add-on enhancements have become available for accessory attachment to standard firearms, thereby significantly upgrading the capability of the firearm. Firearms, such as pistols, rifles, among others, generally include one or more mounting support structures, such as a rail, chassis, or slide. Typically, the mounting support structures are used to receive sights, range finders, and the like, generally to allow the shooter to aim and shoot more accurately. In general, accessories to firearms are physically mounted using bolts, adjustor plates, cammed levers, friction holds, and other mechanisms; however, such mounting schemes can be time-consuming to attach and remove.
When mounted on a firearm, a sighting accessory is necessarily offset from the firearm barrel, which introduces difficulty for sighting alignment. For example, a laser sight is typically mounted such that the laser beam extends generally parallel to, but offset from, the initial flight path of the projectiles. At close distances, the offset can result in a significant targeting error since the laser beam cannot be coaxial with the barrel. Consequently, there remains a need to accommodate the height offset of a sighting accessory relative to the barrel.
Furthermore, replacing one accessory with another can be a time-consuming endeavor since attachment bolts must be removed, and then replaced for a different accessory. Field replacement becomes, at best, cumbersome and difficult.
In U.S. Pat. No. 9,506,726 titled “ACCESSORY MOUNTING FOR FIREARMS”, issued on Nov. 29, 2016, a firearm mounting surface is presented that includes a recess formed on the topside of a slide of a pistol. The recess includes mounting posts extending upwards from the slide for attachment to a plurality of sights having matching openings and fasteners. A mounting plate, sized to fit within the recess, is configured with through-hole apertures to receive the mounting posts attached to, and extending from, the slide recess top surface. The mounting posts extend upwards from the slide top surface and include a center threaded opening formed coaxial with each post. This allows a threaded screw to attach through an accessory bottom surface into the mounting post. The slide recess further includes projections extending upwards for mating with indentations in the mounting plate—the indentations extending inwards from the outer lateral edges of the mounting plate to receive the projections formed in the recess top surface. The projections fit within the indentations on the mounting plate and fix the mounting plate to the slide, such that the mounting plate cannot shift within the slide recess, i.e., cannot shift or rotate about the slide. The mounting posts secure the plate from upward detachment from the slide.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a firearm with the capability of quickly attaching and removing an accessory with minimum structural attachment components.
It is another object of the present invention to provide a removable, rotatable adaptor plate for mounting on one side to a firearm frame, and on the other side to a firearm accessory.
It is another object of the present invention to provide a removable rotatable adaptor plate that can be readily secured to a firearm frame upon completion of rotation.
A further object of the invention is to provide a pistol having a modified pistol slide capable of receiving a rotatable, releasable adaptor plate that can mount a firearm accessory.
It is yet another object of the present invention to provide a firearm with a mountable, removable, interchangeable accessory structure.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The above and other objects, which will be apparent to those skilled in the art, are achieved in the present invention which is directed to a rotatable accessory mounting assembly for rotatably mounting a firearm accessory to a firearm body, the mounting assembly comprising: an adaptor plate having a top surface, a bottom surface, longitudinal sides, lateral sides shorter than the longitudinal sides, the adaptor plate including: at least one locator stud aperture dimensioned for receiving a locator stud or mounting post; a center aperture for providing a pivot location for the rotatable adaptor plate, the center aperture located adjacent the at least one locator stud aperture, and approximately centered about the adapter plate; a forward facing flange forming one edge of the adaptor plate; and a breech facing flange forming an opposite edge of the adaptor plate.
The adaptor plate further including a through-hole aperture adjacent the forward facing flange or the breech facing flange.
On the adaptor plate bottom surface is a nonround recess centered about each of the at least one locator stud apertures; and an annular recess concentric with the center aperture, and larger in diameter than the center aperture, the annular recess dimensioned to receive an O-ring.
The firearm accessory mounting assembly further includes: at least one locator stud for insertion within each of the at least one locator stud apertures, the locator stud having a nonround head for non-rotational placement within the nonround recess and a threaded post; and at least one locator sleeve for attachment to the threaded post of the at least one locator stud, such that each of the at least one locator studs is secured to the adaptor plate prior to rotational placement of the adaptor plate on a firearm structure.
An O-ring may be situated within the annular recess concentric with the center aperture.
The adaptor plate may include a forward facing sidewall, the forward facing sidewall located adjacent the forward facing flange, and/or a breech facing sidewall, the breech-facing sidewall located adjacent the breech facing flange. The forward facing sidewall and/or the breech facing sidewall may include a cut-out portion or gap.
The firearm accessory mounting assembly may further include a through-hole aperture adjacent the forward facing flange or the breech facing flange, such that the through-hole aperture traverses through at least a portion of the forward facing sidewall or the breech facing sidewall.
The bottom surface of the adaptor plate may include a recessed ramp having sidewalls and a top wall, the recessed ramp extending in continuously decreasing depth from the longitudinal side, projecting laterally inwards towards the through-hole aperture.
The ramp may extend laterally inwards, such that the recessed ramp initiates at an opening at the longitudinal sidewall, the recessed ramp having gradually decreasing depth as the recessed ramp progresses laterally inwards, such that the recessed ramp top wall approximately abuts the adapter plate bottom surface.
The forward facing sidewall or the breech facing sidewall may include: a release lever pocket traversing laterally across the forward facing sidewall or the breech facing sidewall; and a release lever rotatably insertable within the release lever pocket.
For accessory attachment purposes, the firearm accessory mounting assembly may include at least one protrusion or lug extending upwards from the adaptor plate top surface, the at least one protrusion or lug located closer to an edge of the adaptor plate.
In a second aspect, the present invention is directed to a pistol slide for receiving a rotatable accessory mounting assembly, the pistol slide having a top surface, longitudinal sides, and lateral sides shorter than the longitudinal sides, the pistol slide comprising: a recess portion having a planar top surface situated lower than the pistol slide top surface, and interrupted by an approximately centered circular cylinder or disc-shaped protrusion extending from the slide recess portion top planar surface; at least one aperture or recessed indentation located within the recess portion top planar surface; a groove or slot formed at an end of the recess portion, the groove or slot extending laterally across the slide; and an overhang or lip extending inwards within the recess portion, towards the circular cylinder or disc-shaped protrusion, forming a top shelf for the groove or slot.
The at least one aperture or recessed indentation forms an eyelet have two overlapping or interconnecting circular apertures including first and second circular apertures.
The pistol slide further includes a locking plunger pin having a pin head and a shoulder portion, the locking plunger pin received by the first circular aperture, and a low head screw received by the second circular aperture, such that a low rising head on the low head screw retains the shoulder portion of the locking plunger pin, allowing only the locking plunger pin head to be exposed above the recess portion top planar surface. A compression spring is in mechanical communication with the locking plunger pin, such that the locking plunger pin is responsive to the compression spring applying an upwards force towards the recess portion top planar surface.
In a third aspect, the present invention is directed to a firearm comprising: a frame having a top surface, longitudinal sides, and lateral sides shorter than the longitudinal sides; a barrel and receiver assembly; a recess portion in the frame having a planar top surface situated lower than the frame top surface, and interrupted by either an approximately centered circular cylinder or disc-shaped protrusion extending from the recess portion top planar surface, or an approximately centered cylindrically-shaped recess within the top planar surface; at least one aperture or recessed indentation located within the recess portion top planar surface; an overhang or lip extending inwards within the recess portion forming a top shelf for a groove or slot formed at an end of the recess portion, the groove or slot extending laterally across the frame; and an adaptor plate having a top surface, a bottom surface, longitudinal sides, lateral sides shorter than the longitudinal sides, the adaptor plate including: at least one locator stud aperture dimensioned for receiving a locator stud or mounting post; either a center aperture for providing a pivot location for the rotatable adaptor plate, the center aperture located adjacent the at least one locator stud aperture, such that the center aperture is approximately centered about the adaptor plate, the center aperture in rotatable communication with the circular cylinder or disc-shaped protrusion extending from the recess portion top planar surface, such that the adaptor plate is rotatable about the recess portion of the frame, or an approximately centered circular cylinder or disc-shaped protrusion extending from the adaptor plate bottom surface configured to be received by the approximately centered cylindrically-shaped recess within the top planar surface, such that the adaptor plate is rotatable about the recess portion of the frame; a forward facing flange forming one edge of the adaptor plate, or a breech facing flange forming an opposite edge of the adaptor plate, or both; and the forward facing and/or breech facing flanges respectively insertable within the groove or slot formed at a respective end of the recess portion upon rotation of the adaptor plate.
In a fourth aspect, the present invention is directed to a method of attaching a firearm accessory to a firearm, the method comprising: attaching the firearm accessory to a rotatable adaptor plate, the adaptor plate having an aperture or a circular- or disc-shaped protrusion configured for pivoting; placing the adaptor plate into a recess portion of a frame of the firearm, the recess portion having a complementary circular- or disc-shaped protrusion extending upwards from the recess portion for receiving the adaptor plate aperture, or a complementary aperture recessed within a planar surface of the recess portion for receiving the adaptor plate circular- or disc-shaped protrusion; pivoting the adaptor plate about the recess portion, thereby rotating a forward facing and breech facing flange of the adaptor plate into receiving grooves or slots formed at each end of the recess portion, the receiving grooves or slots having an overhang or lip extending inwards with respect to the recess portion.
In a fifth aspect, the present invention is directed to a method of attaching a firearm accessory to a firearm, the method comprising: placing an adaptor plate onto a recess portion of a frame of the firearm, the adaptor plate including: a top surface, a bottom surface, longitudinal sides, lateral sides shorter than the longitudinal sides; at least one locator stud aperture dimensioned for receiving a locator stud or mounting post, the at least one aperture located closer to a first edge of the adaptor plate; at least one protrusion or lug extending upwards from the adaptor plate top surface, the at least one protrusion or lug located closer to a second edge of the adaptor plate opposite the first edge; a center aperture for providing a pivot location for the rotatable adaptor plate, the center aperture located adjacent the at least one aperture and at least one protrusion or lug, such that the center aperture is approximately centered about the adaptor plate; a forward facing flange forming one edge of the adaptor plate; and a breech facing flange forming an opposite edge of the adaptor plate; pivoting the adaptor plate about the center aperture when the adaptor plate is placed within the recess portion of the firearm frame, and the center aperture is in rotatably communication with a circular cylinder or disc-shaped protrusion extending from a top planar surface of the recess portion; sliding the forward facing and the breech facing flanges into a groove or slot formed at each end of the recess portion, the groove or slot extending laterally across the frame, having a curvature, and having an overhang or lip extending inwards within the recess portion, towards the circular cylinder or disc-shaped protrusion, forming a top shelf for the groove or slot; and attaching the firearm accessory to the adaptor plate either before the adaptor place is placed onto the recess portion, or afterwards.
In a sixth aspect, the present invention is directed to a firearm recess portion filler comprising a rotatable adaptor plate having a top surface, a bottom surface, longitudinal sides, lateral sides shorter than the longitudinal sides, the rotatable adaptor plate including: a center circular recess or a circular-shaped protrusion on the rotatable adaptor plate bottom surface for providing a pivot location for the rotatable adaptor plate; a forward facing flange forming one edge of the rotatable adaptor plate; and a breech facing flange forming an opposite edge of the rotatable adaptor plate; wherein the rotatable adaptor plate top surface forms part of the firearm top surface.
The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:
Embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
It will be understood that, although the terms first, second, etc., may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “include” and/or “including” when used herein, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
Relative terms such as “below,” “above,” “upper,” “lower,” “horizontal,” “vertical,” “top,” “bottom,” “rear,” “front,” “side,” or the like may be used herein to describe a relationship of one element or component to another element or component as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.
Additionally, in the subject description, the words “exemplary,” “illustrative,” or the like are used to mean serving as an example, instance or illustration. Any aspect or design described herein as “exemplary” or “illustrative” is not necessarily intended to be construed as preferred or advantageous over other aspects or design. Rather, use of the words “exemplary” or “illustrative” is merely intended to present concepts in a concrete fashion.
In describing the preferred embodiment of the present invention, reference will be made herein to
The present invention generally relates to after-market modifications to certain types of firearms to accommodate accessories that enhance the firearm's performance. In this regard, an embodiment of the invention is directed to an accessory attachment system for connecting an accessory to a modern-style firearm, such as a handgun slide assembly. In the case of the modern-style handgun, the slide mechanism is primarily comprised of an inverted U-shaped steel shell having precision-machined tips that match channel rails machined into the bottom handle assembly. The topside of the slide mechanism is generally adapted to receive and support an accessory. In a preferred embodiment, the topside of the slide mechanism is modified to receive an attachable, rotatable, mounting platform or adaptor plate made of rigid material, which may be metal or metal alloy. (The terms “mounting platform” and “adaptor plate” are used interchangeably herein.) The slide is modified to allow the adaptor plate to rotate to a secure position upon completion of rotation, such that the adaptor plate does not move once secured. Movement is restricted both in the rotational direction as well as in an upward direction perpendicular to the longitudinal direction of the slide, i.e., perpendicular to the barrel axis. The accessory mounting assembly incorporates structural forms and/or hardware to secure the adaptor plate to the pistol side top surface on one side, and to secure an accessory to the platform on the other side.
The accessory mounting assembly is configured as a releasably attachable, rotatable platform or adaptor plate, formed on one side to fit and attach to a firearm rail, chassis, or pistol slide, and on the other side—the “top side”—mounting structures are presented for receiving firearm accessories. Structures are defined for securing the mounting assembly such that the firearm receiving surface is capable of accepting and securing the platform or adaptor plate from movement after attachment. It is possible for the adaptor plate to receive more than one accessory, and the present invention is not limited to one accessory per adaptor plate. For illustrative purposes, however, the present description shall refer to an adaptor plate as receiving a single accessory without limiting the scope of the invention having an adaptor plate being able to receive a plurality of accessories.
Adaptor plate base section 12 includes apertures and protrusions to assist in securing an accessory to the adaptor plate. In at least one illustrative embodiment, a raised forward sidewall 14 extends perpendicularly upwards from adaptor plate base section 12; forward sidewall 14 being recessed from the forward end of adaptor plate 10 such that a forward facing flange 16 is formed by the adaptor plate edge extending forward in the longitudinal direction beyond forward face 14a of forward sidewall 14. Similarly, a raised breech sidewall 18 extends perpendicularly upwards from adaptor plate base section 12; breech sidewall 18 being disposed inwards from the aft or breech end of adaptor plate 10 such that a breech facing flange 20 is formed by the adaptor plate edge extending outwards in a longitudinal direction relative to the aft or breech face 18a of sidewall 18. As will be shown in greater detail below, once adaptor plate 10 is rotated into place within the slide recess portion, flanges 16, 20 are used to secure adaptor plate 10, and thus adaptor plate base section 12, from any upwards movement away from the firearm mounting structure, such as a pistol slide.
In at least one embodiment, it is possible for the adaptor plate to be employed without forward and breech sidewalls. Each lateral end of the adaptor plate (forward and breech end) will still act as extended portions of the adaptor plate that function in the same manner as the aforementioned flanges, for attachment support within a modified pistol slide recess portion.
In the embodiment depicted in
At least one locator stud aperture 24 is situated through adaptor plate 10, shown in the embodiment of
In order to ensure that an accessory, once attached, does not exhibit undesirable rotation relative to the adaptor plate 10, in concert with the locator studs at least one lug or protrusion 26, located between aperture 22 and forward sidewall 14, can be used to interlock with a complementary indentation or receiving aperture on an accessory bottom surface. Two lugs or protrusions are generally employed on the adaptor plate for this purpose. The interlocking of the at least one lug or protrusion 26 with the complementary indentation or receiving aperture on the accessory bottom surface prohibits the accessory from rotation about adaptor plate 10 once the accessory is secured to the adaptor plate. The shape, number, and placement of lugs or protrusions 26 may vary depending upon the complementary indentations or receiving apertures in the bottom surface of the accessory. It is envisioned that an adaptor plate may be dedicated to a certain accessory or set of accessories, such that the shape and placement of lugs or protrusions 26 are aligned with the given suite of accessories. Lugs or protrusions 26 are separated, adjacent each lateral side of the adaptor plate, and assist in prohibiting the attached accessory from lateral rotation with respect to the adaptor plate.
According to one attachment scheme of the present invention, in order to lock adaptor plate 10 into place in the pistol slide, such that rotation is prohibited, the adaptor plate is designed to receive a locking plunger pin head extending from the pistol slide, as discussed further below. Sidewall 14 includes a cutout portion or gap 28, along with exposed through-hole 30 at the bottom of the cutout portion configured to receive a locking plunger pin, which when extended into through-hole 30 prohibits rotational movement of adaptor plate 10. Cutout portion 28 is depicted as semi-circular in shape; however, other shaped cutouts or gaps are not prohibited. Moreover, sidewall 14 may be shorter, segmented, or truncated, such that through-hole 30 is exposed.
The height of each sidewall may be dimensioned for aesthetic purposes, so that the top of the sidewall is planar with the top surface of the slide. In another embodiment, through-hole 30 may be formed in said adaptor plate without an accompanying sidewall, such that the sidewall is eliminated and only the through-hole is exposed for receiving the locking plunger pin. The function of through-hole 30, as described herein, is not altered if a sidewall is not present. Furthermore, the placement of through-hole 30 is dependent upon the location of the locking mechanism in relation to the receiving structure on the firearm (pistol slide), placing the through-hole aperture on either the forward-facing side of the adaptor plate or the breech facing side, and the present invention is not regulated to any one location over the other.
As shown in
Aperture 22 is concentric with annular recess 22a, which is dimensioned to receive O-ring 40. Locator stud apertures 24 are shown approximately centered about indentations 34, which in turn provide a recess for locator stud head 36a (not shown). At the forward end of adaptor plate 10 is through-hole 30, and adjacent thereto is a recessed ramp 50. Ramp 50 extends in a continuously decreasing depth from longitudinal side 12a, projecting laterally inwards towards through-hole 30. The largest depth coincides with the opening 50b at one longitudinal side 12a. The depth of ramp 50 gradually decreases as the ramp extends inwardly towards through-hole 30, such that ramp 50 has no appreciable depth at its inward-most distance 50a from its origin 50b at the longitudinal side wall. The purpose of ramp 50 is to provide an operational downwards directing force to a spring-actuated locking plunger pin 42 during rotation of adaptor plate 10 into locking position.
Ramp 50 is designed and configured to accept the head of spring-actuated locking plunger pin 42 upon rotation of adaptor plate 10. As depicted in
Slide recess portion 60 is terminated at each end by an overhang or lip 64 that extends inwards within the recess portion, in a longitudinal direction towards disc-shaped protrusion 62, such that a groove or slot 66 is formed at each end of recess portion 60. Grooves or slots 66 on each side of slide recess portion 60 are dimensioned to receive the adaptor plate flanges 16, 20, respectively, upon rotation of adaptor plate 10 about disc-shaped protrusion 62. Upon completion of rotation, overhangs or lips 64 act to secure adaptor plate 10, and once secured, prohibit adaptor plate 10 from lifting upwards relative to the top surface 60a of the slide recess portion 60.
Referring to
During initial rotation, the opening 50b at the longitudinal sidewall 12a of base section 12 slides over locking plunger pin head 44. As adaptor plate 10 continues to rotate to its locking position, the decreasing depth of ramp 50 continues to push locking plunger pin 42 further into slide 32 in a downwards motion. Once the rotation causes the inward-most distance 50a of ramp 50 to contact the locking plunger pin head 44, the locking plunger pin head 44 within aperture 68b becomes fully depressed under a biasing compression force, and is approximately co-planar to the top planar surface 60a of slide recess portion 60. At this point in the rotation, locking plunger pin head 44 will contact the bottom planar surface 12d of base section 12 at a small planar section 56 adjacent through-hole 30. Subsequent rotation will move the adaptor plate 10 relative to the locking plunger pin head 44 towards aperture 30, where the upward force of compression spring 46 will cause locking plunger pin head 44 to extend within through-hole 30, locking adaptor plate 10 in place against any further rotation.
Based on the illustrative, exemplary embodiments identified above, the present invention allows for interchangeable, rotatably attachable adaptor plates, each of which can be mounted in advance to a desired accessory. The user has the ability to exchange one accessory for another by simply rotatably removing the adaptor plate from the firearm, and replacing with a new adaptor plate having a predetermined accessory already mounted thereon, or removing the accessory from the current adaptor plate and placing a new accessory thereon. In event of the latter, this may be an in-field transition that would not require the removal of any bolts or screws. Only the adaptor plate is attached to the firearm; the accessory being completely secured to the adaptor plate.
In yet another embodiment, if no accessory is desired for mounting, a firearm recess portion filler in the form of a plain adaptor plate 200 having no accessory mounting features may be utilized in place of the adaptor plate capable of holding an accessory.
In a further embodiment of the present invention, a method of attaching a firearm accessory to a firearm is provided, where the method includes: a) attaching a firearm accessory to a rotatable adaptor plate, the adaptor plate having an aperture or a circular- or disc-shaped protrusion configured for pivoting; b) placing the adaptor plate into a recess portion of the frame of the firearm, where the recess portion has a complementary circular- or disc-shaped protrusion extending upwards from the recess portion for receiving the adaptor plate aperture, or a complementary aperture recessed within a planar surface of the recess portion for receiving the adaptor plate circular- or disc-shaped protrusion; c) pivoting the adaptor plate about the recess portion, thereby rotating a forward facing and breech facing flange of the adaptor plate into receiving grooves or slots formed at each end of the recess portion, where the receiving grooves or slots have an overhang or lip extending inwards with respect to said recess portion.
The adaptor plate aperture is approximately centered about the adaptor plate, and the adaptor plate aperture is in rotatable communication with the circular- or disc-shaped protrusion extending from the recess portion, such that the adaptor plate is rotatable about the recess portion.
Conversely, the adaptor plate circular- or disc-shaped protrusion is configured for pivoting, providing a pivot location for the adaptor plate, where the adaptor plate circular- or disc-shaped protrusion extends from a bottom surface of the adaptor plate and is configured to be received by a firearm recess portion complementary aperture, such that the adaptor plate is rotatable about the recess portion.
In yet another embodiment, a method of attaching a firearm accessory to a firearm includes the following:
The method further including locking the adaptor plate from rotation by compressing a locking plunger pin upon rotation of the adaptor plate, and releasing the locking plunger pin into a receiving aperture of the adaptor plate when the rotation is complete.
Or, conversely, locking the adaptor plate from rotation by rotating a release lever having a stopping segment through an aperture in the adaptor plate and into an aperture within a top surface of the recess portion.
While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.
