Handgun frame conversion system

Abstract

This invention discloses embodiments which disclose a handgun frame conversion and adapter system which provides for the conversion of use of a handgun frame from use with a first slide to use with a second and dissimilar slide (such as allowing a Glock® Gen 1, Gen 2 or Gen 3 slide to be used on a Gen 4 or Gen 5 Glock® compatible frame). Aspects of this frame conversion system include a conversion adapter which is installable and removable from the frame portion of the handgun, thereby allowing any one of a number of handgun slides to be mounted or installed on one frame.

Claims

1. A handgun frame adapter system wherein two or more dissimilar handgun slides may be operably mounted to one handgun frame, the adapter system comprising: a handgun frame configured to operably receive a first predetermined handgun slide, the handgun frame including opposing notches defined in an inner surface of the handgun frame and configured to receive and retain a conversion adapter; and a conversion adapter, which when mounted within a front portion of the handgun frame, allows the handgun frame to operably receive a second predetermined handgun slide, the conversion adapter being comprised of: a U-shaped adapter body with an outer surface, an inner surface a front end and a rear end, the inner surface and outer surfaces being generally arcuate, and with the outer surface including one or more protrusions thereon which are configured to insert into the notches in the inner surface of the front portion of the frame to operably attach the conversion adapter to the front portion of the frame; the adapter body further including a center aperture in the semi-circular cover portion and the adapter body being configured to mount at or near the front surface of the slide between the slide and frame such that the adapter body is a barrier to dust entering between the slide and the frame.

2. The handgun frame adapter system as recited in claim 1, and further wherein the first predetermined handgun slide is a dual stage spring slide and the second predetermined handgun slide is single stage spring slide.

3. The handgun frame adapter system as recited in claim 1, and further wherein the first predetermined handgun slide is a Glock® compatible generation 4 or generation 5 slide and the second predetermined handgun slide is one or more of a Glock® or Glock® compatible generation 1, generation 2 and/or generation 3 handgun slide(s).

4. The handgun frame adapter system as recited in claim 1, and further wherein the conversion adapter is mounted to the handgun frame as follows: the handgun frame includes opposing notches defined in an inner surface of the frame, configured to receive and retain the conversion adapter which is comprised of: a U-shaped adapter body with an outer surface, an inner surface a front end and a rear end, the inner surface and outer surfaces being generally arcuate, and with the outer surface including one or more protrusions thereon which are configured to insert into the notches in the inner surface of the front portion of the frame to operably attach the conversion adapter to front portion of the frame.

5. The handgun frame adapter system as recited in claim 4, and further wherein the conversion adapter is configured such that a surface of the front-end fills most of a gap between the second predetermined slide and the front portion of the handgun frame.

6. The handgun frame adapter system as recited in claim 5, and further wherein the rear end of the conversion adapter is sloped downwardly to the inner surface of the frame.

7. The handgun frame adapter system as recited in claim 1, and further wherein the front portion of the handgun frame includes a fastener aperture which aligns with a fastener aperture in the conversion adapter such that a fastener may be inserted into both fastener apertures to secure the conversion adapter to the handgun frame.

8. The handgun frame adapter system as recited in claim 1, and further wherein the conversion adapter is mounted to the handgun frame through one or more of the following: adhesive between the inner surface of the handgun frame and the outer surface of the conversion adapter; a heat weld between the inner surface of the handgun frame and the outer surface of the conversion adapter; a dovetail joint between the inner surface of the handgun frame and the outer surface of the conversion adapter; and/or a rabbet joint between the inner surface of the handgun frame and the outer surface of the conversion adapter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention are described below with reference to the following accompanying drawings.

(2) FIG. 1 is a side perspective elevation view of an example of one embodiment of this frame adapter system invention;

(3) FIG. 2 is a side perspective elevation view of an example of one embodiment of a conversion adapter which may be utilized in embodiments of this frame adapter system invention;

(4) FIG. 3 is a perspective elevation view of the embodiment of the frame adapter illustrated in FIG. 1 with the embodiment of the conversion adapter illustrated in FIG. 2 installed therein;

(5) FIG. 4 is a perspective elevation and closeup view of the front portion of the handgun illustrated in FIG. 1;

(6) FIG. 5 is a perspective elevation and closeup view of the conversion adapter illustrated in FIG. 2;

(7) FIG. 6 is a front elevation view of the front of the slide (including the barrel), the front portion of the frame, and showing the conversion adapter;

(8) FIG. 7 is a front elevation perspective view of the front of the slide (including the barrel), the front portion of the frame, and showing the conversion adapter;

(9) FIG. 8 is a front elevation perspective cutaway view of the front of the slide (including the barrel), the front portion of the frame, and showing the conversion adapter;

(10) FIG. 9 is a front elevation perspective view of the front of the slide (including the barrel), the front portion of the frame, and showing the gap or aperture of the combination without the conversion adapter there-between;

(11) FIG. 10 is a front elevation perspective cutaway view of the front of the slide (including the barrel), the front portion of the frame, and showing the gap or aperture of the combination without the conversion adapter there-between;

(12) FIG. 11 is a front elevation view of the front of the slide (including the barrel), the front portion of the frame, and showing the combination without the conversion adapter and with a gap there-between;

(13) FIG. 12 is a front perspective view of one embodiment of a conversion adapter that may be used in practicing this invention;

(14) FIG. 13 is a front-end view of the embodiment of the conversion adapter shown in FIG. 12;

(15) FIG. 14 is a front perspective cutaway view of the embodiment of the conversion adapter shown in FIG. 12, illustrating a taper on the rear-end of the adapter body;

(16) FIG. 15 is a top view of the embodiment of the conversion adapter shown in FIG. 12;

(17) FIG. 16 is a front perspective view of a typical Glock® Gen 4 slide on a Gen 4 compatible frame;

(18) FIG. 17 is a top view of a single stage handgun spring (on top part of image) and a dual stage handgun spring (lower part of image);

(19) FIG. 18 is a front elevation perspective view of an example of an alternative embodiment of a conversion adapter that may be used in embodiments of this invention, one in which a screw fastener is used to attach the conversion adapter to the handgun frame;

(20) FIG. 19 is a front elevation perspective view of the alternative embodiment of a conversion adapter illustrated in FIG. 18, and is shown inserted and secured in the front portion of a handgun frame via a screw fastener;

(21) FIG. 20 is a front perspective view of one ornamental embodiment of a handgun frame conversion adapter;

(22) FIG. 21 is a rear end view of the one ornamental embodiment of the handgun frame conversion adapter referenced in FIG. 20;

(23) FIG. 22 is a left side view, and also a right side view, of the one ornamental embodiment of the handgun frame conversion adapter referenced in FIG. 20;

(24) FIG. 23 is a front end view of the one ornamental embodiment of the handgun frame conversion adapter referenced in FIG. 20;

(25) FIG. 24 is a top view of the one ornamental embodiment of the handgun frame conversion adapter referenced in FIG. 20; and

(26) FIG. 25 is a bottom view of the one ornamental embodiment of the handgun frame conversion adapter referenced in FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(27) Many of the fastening, connection, manufacturing and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art or science; therefore, they will not be discussed in significant detail. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application or embodiment of any element may already be widely known or used in the art or by persons skilled in the art or science; therefore, each will not be discussed in significant detail.

(28) The terms “a”, “an” and “the” as used in the claims herein are used in conformance with long-standing claim drafting practice and not in a limiting way. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one of such elements, but instead mean “at least one”. It should be noted that Glock® is a trademark owned by Glock®, Inc., Smyrna, Ga., and there is no affiliation of any kind between the inventions, inventors or products described herein with Glock®, Inc.

(29) FIG. 1 is a side perspective elevation view of an example of one embodiment of this frame adapter system invention, illustrating handgun frame 101 with front portion 103 of handgun frame 101, trigger guard 102, front opening 104, internal surface 105 (which is shown arcuate in nature), and notch 106 (shown more fully in FIG. 4). The notch 106 is configured to receive a conversion adapter 120 (illustrated in FIGS. 2, 3 & 5) with protrusions (such as items 122 in FIG. 5) on the outer surface thereof.

(30) When the conversion adapter 120 is inserted into the front portion 103 of the frame, the protrusions 122 on the outer surface 121b of the conversion adapter 120 insert into the notches 106 (preferably on both or opposing sides of the frame 101) to secure the conversion adapter 120 into the front portion of the frame 101 (as shown assembled in FIG. 3).

(31) A tight fit of the conversion adapter 120 in the frame 101 is preferable and this can be accomplished through tight tolerances and through designing and sizing the internal surface 105 of the frame 101 relative to the design and sizing of the external surface 121b of the conversion adapter 120 to have some flexibility or resilience, to achieve a tight fit or to enable the conversion adapter 120 to be snapped into position in a locked fit with the protrusions (items 122 in FIGS. 2 & 5 for example) in the frame 101. FIG. 1 and FIG. 5 further illustrate removal slot 121h and 121g in the adapter body 121, which provides an indentation or space to allow easier mechanical removal of the conversion adapter 120 from the handgun frame.

(32) FIG. 2 is a side perspective elevation view of an example of one embodiment of a conversion adapter 120 which may be utilized in embodiments of this frame adapter system invention. FIG. 2 illustrates conversion adapter body 121, with interior surface 121a, exterior surface 121b, protrusions 122 which are configured to be securely received within notches (item 106 in FIGS. 1 & 4).

(33) FIG. 3 is a perspective elevation view of the embodiment of the frame conversion adapter illustrated in FIG. 1 with the embodiment of the conversion adapter illustrated in FIG. 2 installed or inserted in the front portion 103 of the frame 101 of the handgun. FIG. 3 illustrates the conversion adapter body 121, inner surface 121a, top surface 121e and front surface 121c.

(34) In an additional and alternative embodiment, the conversion adapter as shown in FIG. 3 may, instead of using the notch and protrusion configuration described, be secured through adhesives, glues or welding (through the use of a hot knife, vibration or other means). Although a permanent adaptation may not be preferred in some applications or embodiments, the conversion adapter may be attached to the handgun frame in this way.

(35) FIG. 4 is a perspective elevation and closeup view of the front portion 103 of the handgun frame 101 shown in FIG. 1, illustrating the inner surface 107 of the front portion 103 of the handgun frame, front opening 104, front body portion and inner surface 107 of the frame. FIG. 4 further illustrates one example of an embodiment of a notch 106 that may be formed or disposed on the inside surface 107 of the body 105 of the front portion 103 of the frame, including an upper inner surface 106b of notch 106 (against which the top surface 122a of protrusion 122 may abut) to retain the conversion adapter 120 in the frame—as shown in FIGS. 4 & 5.

(36) FIG. 5 is a perspective elevation and closeup view of the conversion adapter body 121 of the conversion adapter 120 illustrated in FIG. 2, including its front surface 121c, inner surface 121a, outer surface 121b, top surfaces 121e and 121f and rear surface 121d, protrusions 122 (with top surfaces 122a) which are configured to be securely received within notch(es) shown in other figures. It should be noted that, while not shown in FIG. 5, the opposing outer surface of the conversion adapter 120 is the same as this near outer surface shown, including with protrusions 122.

(37) FIG. 6 is a front elevation view of the front of the slide (including the barrel 145), the front portion 103 of the frame, the slide 140 and showing the conversion adapter 121 (including the front surface 121c of the conversion adapter) between the slide 140 and the front portion 103 of the frame. FIG. 6 further illustrates guide rod screw 129 (which may also be referred to as a recoil spring retainer or a slide spring fastener), which contributes to the securement or attachment of the spring (in this example a single stage spring configuration).

(38) For example, the slide 140 in FIG. 6 may be the second predetermined slide and be a Glock® Gen 1, 2 or 3 handgun slide being placed on a Gen 4 or Gen 5 compatible frame (either of which can be the first predetermined slide) with the use of the conversion adapter and conversion system described herein.

(39) FIG. 7 is a front elevation perspective view of the front of the slide 140 (including the barrel 145), the front portion 103 of the frame, and showing the conversion adapter 121 between the slide 140 and the front portion 103 of the frame. It should also be noted from viewing FIGS. 6 & 7 with the conversion adapter 121 installed between the two components, that it may also function as a dust cover or dust shield, depending on how tight the fit is designed to be—especially when compared to FIGS. 9, 10 & 11 where no conversion adapter is shown between the front portion 103 of the frame and the slide 140.

(40) FIG. 8 is a front elevation perspective cutaway view of the front of the slide 140 (including the barrel 145), the front portion 103 of the frame, the conversion adapter 121 (including the front surface 121c and the inner surface 121a).

(41) FIG. 9 is a front elevation perspective view of the front of the slide 140 (including the barrel 145), the front portion 103 of the frame, and showing the aperture or gap 147 (at a gap height as item 148) of the combination of the slide 140 and front portion 103 of the frame without the conversion adapter there-between.

(42) FIG. 10 is a front elevation perspective cutaway view of the front of the slide 140 (including the barrel 145), the front portion 103 of the frame (including inner surface 107 of the frame), and showing the aperture or gap 147 (at a gap height as item 148) of the combination of the slide 140 and front portion 103 of the frame without the conversion adapter there-between.

(43) FIG. 11 is a front elevation view of the front of the slide 140 (including the barrel 145), the front portion 103 of the frame, and showing the combination without the conversion adapter and with a gap there-between (with the gap height shown as item 148).

(44) FIG. 12 is a front perspective view of one embodiment of a conversion adapter 160 that may be used in practicing this invention, illustrating the conversion adapter body 161 of the conversion adapter 160, including its front surface 161c, inner surface 161a, outer surface 161b, front portion top surfaces 161e and rear portion top surfaces 161f, protrusions 162 (with top surfaces 162a) which are configured to be securely received within notch(es) 106 shown in other figures. It should be noted that, while not shown in FIG. 12, the opposing outer surface of the conversion adapter 160 is the same as this near outer surface shown, including with protrusions 162.

(45) FIG. 12 further illustrates removal slot 161i. The removal slots 161i in the outer surface 161b of the adapter body 161 provide space between the outer surface 161b of the adapter body 161 and the inner surface of the frame (such as the installed adapter 232 with removal slot 237 illustrated in FIG. 19). It should be noted that while the removal slot 237 is shown located in the middle of the sides of the U-shape, the removal slots 237 may be located anywhere else with no one particular location being required to practice embodiments of this invention.

(46) FIG. 13 is a front-end view of the embodiment of the conversion adapter 160 shown in FIG. 12, illustrating the conversion adapter body 161 of the conversion adapter 160, including its front surface 161c, protrusions 162 (with top surfaces 162a) which are configured to be securely received within notch(es) in the inner surface of the frame, as shown in other figures.

(47) FIG. 14 is a front perspective cutaway view of the embodiment of the conversion adapter shown in FIG. 12, showing a taper on the rear-end of the adapter body. FIG. 14 illustrates the conversion adapter body 161 of the conversion adapter 160, including its front surface 161c, inner surface 161a, front portion top surface 161e, rear portion top surface 161f, cross-section of front body portion 161g, cross-section of rear body portion 161h (tapered).

(48) While the example of the embodiment shown in FIGS. 12-15 show a conversion adapter 160 with a smooth arcuate inner surface 161a and outer surface 161b, it should be noted that no particular surface contour is required to practice some embodiments of this invention on either the inner surface 161a or the outer surface 161b of the conversion adapter 160. In some embodiments it may be preferred to have a discontinuous outer surface for example to better facilitate the application of adhesives for example to attach the adapter to a particular handgun frame.

(49) FIG. 15 is a top view of the embodiment of the conversion adapter shown in FIG. 12, illustrating the conversion adapter body 161 of the conversion adapter 160, including its front surface 161c, inner surface 161a, front portion top surfaces 161e and rear portion top surfaces 161f, and protrusions 162 (with top surfaces 162a).

(50) FIG. 16 is a front perspective view of a typical Glock® Gen 4 slide on a Gen 4 compatible frame, illustrating the front portion 103 of a Gen 4 compatible frame, with a Glock® Gen 4 slide 180 mounted thereon. From its characteristics relative to this invention and the purpose of this invention, the Glock® Gen 5 is the same or similar to the Gen 4. A comparison of the front surface 182 of the Gen 4 slide with the front of the prior generation Glock® slide shown in FIGS. 6 & 7 for example, illustrates why the Glock® Gen 1, 2 and 3 slides are not designed for and are not compatible with the Gen 4 frame (which is instead designed to receive the Gen 4 slide as shown in FIG. 16). FIG. 16 further illustrates guide rod screw 184, which contributes to the securement or attachment of the spring (in this example a dual stage spring configuration). While FIG. 16 is an image of a Gen 4, the same would apply to a Gen 5 frame.

(51) FIG. 17 is a top view of a single stage handgun spring 200 (on top part of image) and a dual stage handgun spring 210 (lower part of image). FIG. 17 illustrates the differences between the size and nature of the single stage spring 200 versus the dual stage spring 210, including the narrower width or diameter 203 of the single stage spring 200 versus the width or diameter 214 of the dual stage spring 210. FIG. 17 shows the spring 201 around the axis 202 on the single stage spring, and the first spring 211 and the second spring 212 around spring axis 213 on the dual stage spring 210.

(52) It should be noted that even though the Glock® handguns are referred to throughout this specification, that is because the Glock® Gens 1, 2 & 3 have a single stage spring and the Glock® Gens 4 & 5 have the larger diameter dual stage spring configuration. This invention has application beyond Glock® to all handguns wherein it is desired to use a single stage spring-based slide combined with an otherwise dual stage spring-based frame interchangeable with the dual stage spring-based slide.

(53) It should be further noted that embodiments of this invention include modifying (cutting, drilling, etc.) the interior or inner surface of a frame (including an OEM frame) by imparting a notch therein which would then correspond with protrusions on the outer surface of the conversion adapter. Embodiments of this invention further include providing a handgun frame with the notches already cut or molded therein, to receive the adapter. It should still further be noted that embodiments of this invention may include an adapter body without the protrusions, placed in the front portion of the handgun frame to adapt that frame to accept a dissimilar slide (such as for example—accepting or receiving a single stage spring slide for mounting on a handgun frame designed to receive a larger diameter dual stage spring slide).

(54) When the term “notch” is used herein, it is not limited to just a notch, but instead is further defined as an aperture or indentation configured to operably receive and removably retain the protrusion on the exterior of the conversion adapter. Furthermore, when the term “protrusion” is used herein, it is not limited but instead includes any protrusion, projection, protrusion, barb, tab, jut or other extending component configured to be operably positioned within the notch to secure the conversion adapter within the interior of the frame.

(55) It should further be noted that instead of securing the conversion adapter to the inner surface of the handgun frame through a notch and protrusion, it can also be secured to the handgun frame through use of a fastener (as described elsewhere herein), a dovetail joint or connection, rabbet joints or connections, or more permanently affixing it with an adhesive or a heated or welded type of joint with the thermoplastic nature of the frame.

(56) Embodiments of this conversion system in a broader sense involve: providing a handgun frame that has been modified to securely receive a conversion adapter, or modifying said handgun frame to securely receive said conversion adapter. While embodiments described above are directed toward modifying the prior art handgun frame through the placement of a notch, indent or aperture in the interior surface thereof—which correspond to protrusions on the outer surface of the adapter, embodiments of this invention are not limited to that specific method.

(57) Alternative embodiments of this invention may involve providing a handgun frame with for example an aperture through the bottom of the interior surface of the front portion of the handgun frame so that a screw or other fastener may be placed there-through and for example screwed into an internally threaded screw aperture in the outer surface of the conversion adapter. In this alternative embodiment for example, the conversion adapter may then be placed on the interior surface of the handgun frame with the screw aperture in the outer surface of the conversion adapter aligned with the aperture in the handgun frame, and then rotating a screw through both apertures to thereby secure the conversion adapter to the handgun frame. It should be noted that the fastener apertures may be drilled or tapped from through the handgun frame and then into the conversion adapter, or drilled or tapped through the conversion adapter and then into the handgun frame, all within the scope of some embodiments of this invention.

(58) FIG. 18 is a front elevation perspective view of an example of an alternative embodiment of a conversion adapter 232 that may be used in embodiments of this invention, one in which a screw fastener is used to attach the conversion adapter 232 to an inner surface of a handgun frame. FIG. 18 illustrates conversion adapter 232 with inner surface 232c, outer surface 232b, front surface 232d and fastener aperture 232a through the conversion adapter 232.

(59) FIG. 19 is a front elevation perspective view of the alternative embodiment of a conversion adapter 232 illustrated in FIG. 18, and is shown inserted and secured in the front portion 234 of a handgun frame via a screw fastener 233. FIG. 19 illustrates frame 231, front portion of handgun frame 234, inner surface 231a of frame 231 conversion adapter 232, screw fastener 233 inserted in fastener aperture 232a (shown in FIG. 18), and the threaded end of the screw fastener 233 would be screwed or securely inserted into a screw aperture in the handgun frame.

(60) As will be appreciated by those of reasonable skill in the art, there are numerous embodiments to this invention, and variations of elements, components and combinations, which may be used, all within the scope of this invention.

(61) One embodiment of this invention, for example, is a handgun frame adapter system wherein two or more dissimilar handgun slides may be operably mounted to one handgun frame, comprising: a handgun frame configured to operably receive a first predetermined handgun slide; a conversion adapter which when mounted within a front portion of the handgun frame, wherein the conversion adapter allows the handgun frame to operably receive a second predetermined handgun slide.

(62) A further embodiment to that disclosed in the preceding paragraph is: further wherein the first predetermined handgun slide is a Glock® generation 4 or generation 5 slide and the second predetermined handgun slide is one or more of a Glock® generation 1, generation 2 and/or generation 3 handgun slide(s); and/or further comprising: a handgun frame which includes opposing notches defined in an inner surface of the frame, configured to receive and retain a conversion adapter comprised of: a U-shaped adapter body with an outer surface, an inner surface, a front end and a rear end, the inner surface and outer surfaces being generally arcuate, and with the outer surface including one or more protrusions thereon which are configured to insert into the notches in the inner surface of the front portion of the frame to operably attach the conversion adapter to the front portion of the frame.

(63) A further embodiment to that disclosed in the preceding paragraph is further wherein the conversion adapter is configured such that a surface of the front-end fills most of a gap between the second predetermined slide and the front portion of the handgun frame; and in some further embodiments, the rear end of the conversion adapter is sloped downwardly to the inner surface of the frame.

(64) In still further embodiments of the system, a method of utilizing one handgun frame to adaptably receive at least a first predetermined handgun slide and a second predetermined handgun slide dissimilar from the first predetermined handgun slide is provided and which is comprised of: providing a handgun frame configured to operably receive a first predetermined handgun slide; providing a conversion adapter which is operably mounted within a front portion of the handgun frame and mounting the conversion adapter within the front portion of the handgun frame; and operably mounting a second predetermined handgun slide on the handgun frame such that the conversion adapter fills a gap between the front portion of the handgun frame and the second predetermined handgun slide.

(65) A further embodiment to that disclosed in the preceding paragraph is further wherein the first predetermined handgun slide is a Glock® generation 4 or generation 5 slide and the second predetermined handgun slide is one or more of a Glock® generation 1, generation 2 and/or generation 3 handgun slide(s).

(66) In yet another embodiment of this invention, a method of utilizing one handgun frame to adaptably receive at least a first predetermined handgun slide and a second predetermined handgun slide dissimilar from the first predetermined handgun slide may be provided, comprised of: providing a handgun frame with an internal cavity with an internal surface configured to operably receive the first predetermined handgun slide; providing a conversion adapter with an internally threaded aperture in its outer surface which corresponds to a fastener aperture placed in a front portion of the handgun frame; placing the conversion adapter in the front portion of the handgun frame such that the fastener aperture in the outer surface of the conversion adapter is aligned with the fastener adapter in the front portion of the handgun frame; inserting a fastener through the fastener aperture in the frame and into the fastener aperture in the outer surface of the conversion adapter, thereby securing the conversion adapter to the front portion of the handgun frame; and wherein the handgun frame with the conversion adapter secured therein configures the handgun frame to receive the second predetermined slide.

(67) Additional and further embodiments to that stated in the preceding paragraph may include such a method and further wherein: the fastener is a screw which is inserted by threading it through the fastener aperture in the handgun frame and threading it through the fastener aperture in the conversion adapter; and/or the first predetermined slide includes a single stage spring configuration and the second predetermined slide includes a dual stage spring configuration.

(68) In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.