Jack stand and jack combination and method of elevating a load

[0001] This application is a continuation-in-part of application Ser. No. 11/286,788, filed Nov. 23, 2005. This application claims the benefit of that application and incorporates it herein by reference.

[0002] The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. “Rectangular” includes square.

[0003] Hydraulic jacks are used to raise many types of loads above ground level such as, for example, automobiles. If the jack remains in place after elevating a load, over time due to leakage of hydraulic fluid, the jack gradually lowers the load. The best practice is to use a jack stand placed under the load to maintain the load elevated and remove the jack once the jack stand is in place.

[0004] A problem occurs in connection with lifting automotive vehicles having a uni-body frame that frequently is bent when the jack is improperly positioned beneath the vehicle. Moreover, even if the jack is placed properly beneath the frame at a position that avoids bending the frame, the jack stand is often placed beneath the frame at an improper position, resulting in the frame bending under the weight of the vehicle when the jack in lowered. Placing the jack stand next to the elevated jack is no guarantee that it is correctly position to avoid bending the frame when the jack is lowered.

[0005] This invention has one or more features as discussed subsequently herein. After reading the following section entitled “DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THIS INVENTION,” one will understand how the features of this invention provide its benefits. The benefits of this invention include, but are not limited to, providing: (a) a jack stand and method that enables the jack stand to be precisely located with respect to an automotive vehicle frame so the frame does not bend under the weight of the vehicle when the jack in lowered, (b) a jack stand enabling a plurality of such stands to be stacked one upon another, (c) an especially configured jack stand facilitating its manufacture from metallic sheet material using conventional metal punching, bending and welding techniques, (d) a jack stand that enables several stand to be stacked one upon the other, (e) a jack stand that may be folded to reduce its size for storage, and (f) a jack stand that may be inserted into a small space beneath an automobile or other load.

[0006] Without limiting the scope of this invention as expressed by the claims that follow, some, but not necessarily all, of its features are:

[0007] One, this invention includes the combination of a jack stand and jack where the jack stand has a moveable, elongated column that is elevated as the jack is elevated. A vertically oriented, compact hydraulic jack may be used. The column is vertically oriented and moveable between a plurality of different elevated positions. The column may have an overhanging member and the stand may have a platform beneath the overhanging member. The jack is placed on the platform and positioned to elevate the column as the jack is elevated.

[0008] Two, the spatial relationship between the column in a completely lowered position and the vertical height of the jack with its piston in a completely lowered position are another feature of this invention. Under these conditions the underside of the overhanging member of the column is above a top side of the platform a predetermined distance substantially equal to the vertical height of the jack with its piston in a completely lowered position. Thus, a head end of the jack's piston engages this underside, simultaneously raising the column as the jack is elevated. When the pin element is in place holding the jack in a selected elevated position, the jack may be lowered and removed from the platform.

[0009] Three, the support column is held in a selected one of plurality of different elevated positions after being elevated by the hydraulic jack and upon removal of the hydraulic jack from the platform. Different means may be used to hold the raised column in a selected elevated position. One means is that the support column may include a series of pairs of aligned, opposed openings spaced apart along the support column and a removable pin element is inserted though opposed opening when the selected elevated position is attained. Another means is a ratchet mechanism that holds the support column in a selected one of plurality of different elevated positions.

[0010] Four, the column may be detachable and may have a substantially rectangular shape. The column may have at the upper end a locator member with a longitudinal centerline of the stand intersecting a center of the locator member. The locator member may be substantially at a right angle to both the column and a plate member forming the overhanging member and the plate member may be at a right to the column. The locator member may have a central element with opposed ends and a pair of opposed outwardly and upwardly extending flange members, each one connected to one of the ends of the central element.

[0011] Five, the stand may comprise a base and a receptacle. The base has one or more of the following characteristics. It may have a substantially pyramid configuration. It may include at or near a bottom end a jack platform and at a top end the receptacle, which may be hollow and have an open upper end. It may have a longitudinal centerline and the receptacle is oriented lengthwise along the centerline. It may have a hollow interior and a partially open side providing access to the interior, enabling the jack to be seated on the platform with the jack at least partially positioned within the interior and its piston member directly under the overhanging member of the column. It may comprise a pair of sections, with the sections being moveable relative to each other to increase and decrease the height of the base. These sections may be substantially mirror images of each other and they may be attached at upper ends thereof to pivot. Bracing structure extending between lower ends of the sections may be used to increase the rigidity of the base.

[0012] Six, the receptacle may be fixedly attached to the base of the jack stand or it may be a separate detachable member. The receptacle may have dimensions substantially the same as the dimensions of the column to enable the lower end of the column to be inserted into the open upper end of the receptacle. For example, the receptacle and the column may each be of substantially the same rectangular in cross-sectional configuration. The receptacle may include a pair of aligned, opposed openings that enable the removable pin element to be inserted into one opening in the receptacle and through the openings in one pair of the series in the column aligned with the openings in the receptacle and through the other opening in the receptacle. With the pin element so inserted, it maintains the column in a selected elevated position.

[0013] Seven, in yet a further embodiment of the invention, the support column may include an elongate first rod, and an elongate second rod. The first rod is moveable in a direction parallel with the second rod. The plate member is attached to the first rod and positioned substantially at a right angle to the first rod at an upper end of the first rod. A base is provided including an open upper end configured to receive the support column. The support column is moveable along the first axis while received within the open upper end of the base, and the jack stand is configured to be activated by a hydraulic jack having a piston, the piston having a second elongate axis, and wherein the jack stand is positioned for use in relation to the hydraulic jack with the piston in contact with the plate member such that the second axis is not coaxial with the first axis. When the piston is raised to elevate a load, the support column is raised.

[0014] In a further aspect, the support column is configured to be held in a selected one of plurality of different elevated positions in relation to the base after the support column is raised by the hydraulic jack. A first ratchet mechanism may be used for holding the support column in a selected one of a plurality of different elevated positions in relation to the base. In further detail, the first ratchet mechanism may be configured to hold the second rod in relation to the base. In yet further detail, the first rod may be configured to be held in a selected one of a plurality of different elevated positions in relation to the second rod after the support column is raised by the hydraulic jack, where the holding may be performed by a second ratchet mechanism.

[0015] Eight, the invention may be an entire jacking system comprising a jack stand as described above, in combination with a hydraulic jack including a piston that has an outer sleeve and an inner sleeve, the inner sleeve being slidable within the outer sleeve to provide a telescoping piston. In this system, the features of the jack stand as described above are included.

[0016] Finally, a method of lifting a load is included in this invention that comprises:

• • [0017] (a) positioning beneath the load at a predetermined location relative to the load a jack stand including a vertically oriented column having a first elongate axis, the column being moveable between a plurality of different elevated positions and having an overhanging member;
  • [0018] (b) positioning a vertically oriented, compact hydraulic jack having a piston member next to the stand beneath the overhanging member, the piston member having a second elongate axis, wherein the second axis is not coaxial with the first axis;
  • [0019] (c) actuating the hydraulic jack to elevate the piston member along the second axis so that the piston member engages an underside of the overhanging member and elevates the column to bring an upper end of the column into contact with the load; and
  • [0020] (d) holding the column in a selected elevated vertical position.

[0021] These and other advantages of the invention will become more apparent from the following detailed description thereof and the accompanying exemplary drawings.

[0046] This invention comprises a unique jack stand used with a conventional hydraulic jack, for example, a bottle jack 12. There are several embodiments of the jack stand illustrated, namely, the jack stand 10 shown in FIGS. 1 through 7, the jack stand 10a shown in FIGS. 8 through 12, and the jack stand 10b shown in FIGS. 13 through 16. In the embodiments illustrated, each stand includes a elongated support column 16, a plate member 28 substantially at a right angle to the column at an upper end of the column, and a base 11 including at or near a bottom end a jack platform 18 and at a top end a hollow receptacle 13 having an open upper end into which the support column is inserted during use. The base 11 may have a rigid, one piece a substantially pyramid configuration as illustrated in the embodiments shown in FIGS. 1 through 7 and FIGS. 13 through 16. Or, the base 11 may have a foldable, two-piece substantially pyramid configuration as illustrated in the embodiment shown in FIGS. 8 through 12.

[0047] The support column 16 is moveable lengthwise while positioned within the receptacle 13, and the hydraulic jack 12 is adapted to sit on the platform 18. The hydraulic jack 12 includes a piston 14 having an upper end that is beneath the plate member 28 when the jack 12 is sitting on the platform 18. The piston 14 elevates the column 16 as the piston 14 is raised by manually actuating the jack 12. Upon removal of the hydraulic jack 12 from the platform 14, the support column 16 is held in a selected one of plurality of different elevated positions. This may be accomplished by means of a pin element 22 used in the embodiments depicted in FIGS. 1 through 7 and FIGS. 8 through 12, or a ratchet mechanism 60 used in the embodiment depicted in FIGS. 13 through 16.

[0048] FIGS. 1 through 7

[0049] As illustrated in FIG. 1, the jack stand 10 of this invention is used with the bottle jack 12. The bottle jack 12 is compact and normally operated in a vertical orientation. Its hydraulically actuated piston 14 elevates a load in response to operating its piston raising and lowering mechanism 12a by manually manipulating its detachable handle 17 shown in dotted lines in FIG. 1. A head end 14a of the piston 14 has a knurled surface.

[0050] The stand 10 includes the base 11, the receptacle 13, the elongated support column 16 received within the receptacle, and the jack platform 18 for supporting the bottle jack 12 in an upright, vertical orientation. The receptacle 13 has a substantially rectangular cross-sectional shape formed by opposed front side 13a and back side 13b (FIG. 6), and a right hand side 13c as viewed in FIG. 6 and a left hand side 13d as viewed in FIG. 5. It includes an opening 20a in the right side 13c and an opening 20b (FIG. 1) in the left side 13d that are aligned and opposed to each other. The removable pin element 22, which has a grip ring 22a at one end, holds the support column 16 in a selected elevated position.

[0051] The support column 16 is detachable and has a substantially rectangular cross-sectional shape formed by opposed front side 16a and back side 16b (FIG. 6), and a right hand side 16c as best viewed in FIG. 6 and a left hand side 16d as best viewed in FIG. 2. There are openings 25a, 25b, and 25c equally spaced lengthwise along the right hand side 16c and openings 26a, 26b, and 26c equally spaced lengthwise along the left hand side 16d. This arrangement provides a series of pairs 25a-26a, 25b-26b, and 25c-26c of aligned, opposed openings spaced apart along the opposed sides 16c and 16d of the support column 16 between an upper end E1 and a lower end E2 of the column. The cross-section dimensions of the receptacle 13 and the column 16 are substantially the same, with the cross-section dimensions of the column being slightly less. This enables the lower end E2 of the column 16 to be inserted into an open upper end E3 (FIGS. 1 and 2) of the receptacle 13 in a male-female mating relationship.

[0052] The load supporting plate member 28 is attached to the column 16 in a manner to overhang the platform 18. This plate member 28 has an upper substantially flat top 28a with a flat underside 29 (FIG. 2) and downwardly extending sides 28b, 28c, 28d, and 28e that are substantially at a right angle to the flat top and underside. The column's rear side 28e is welded to the front side 16a of the column 16 at the upper end E1 substantially at a right angle to the column. The column 16 has at the upper end E1 a locator member 30 welded to this end. The locator member 30 is at substantially a right angle to the plate member 28 and is substantially concave or U-shape to better engage a frame of an automotive vehicle or other object being lifted. A longitudinal centerline C (FIG. 2) of the stand 10 intersects the center C1 of the locator member 30 when the column 16 is inserted into the receptacle 13. As best shown in FIG. 5, the locator member 30 has a central element 30a with opposed ends E4 and E5 and a pair of opposed outwardly and upwardly extending flange members 30b and 30c. Each flange member is integral with the ends of the central element 30a.

[0053] The base 11 has a substantially pyramid configuration and a longitudinal centerline coincident with the centerline C that intersects a truncated apex end E6. Four flat inwardly slanting, substantially triangular configured sides 11a, 11b, 11c (FIG. 6), and 11d (FIG. 6) form a hollow interior 32. The receptacle 13 is welded to the apex end E6 and oriented lengthwise along the centerline C and centrally positioned with respect to the centerline. The opposed sides 11a and 11c each have central triangular cut-a-way 34a and 34c, providing, respectively, lower wall sections 36a and 36b (FIG. 6). As discussed subsequently in greater detail, the central triangular cut-a-ways 34a and 34c provide access to the interior 32. Substantially inverted V-shaped cut-a-ways 39a and 39b are respectively in the opposed triangular configured sides 11b and 11d (FIG. 6), and substantially inverted U-shaped cut-a-ways 41a and 41b (FIG. 6) are respectively in the opposed triangular configured sides 11a and 11c. These cut-a-ways 39a and 39b and 41a and 41b form foot elements F1, F2, F3, and F4 (FIG. 6) at the bottom corners of the base 11.

[0054] The jack platform 18 is at or near a bottom end E7 of the base and it includes a flat top side 18a, a right side 18b as viewed in FIG. 6, a left side 18c, a front side 18d, and an open rear side 18e (FIG. 6). The sides 18b, 18c, and 18d are substantially at a right angle to the flat top side 18a. A pair of upwardly and inwardly slanted aligned slots 44a (FIG. 1) and 44b respectively in the sides 18b and 18c enable the jack platform 18 to be mounted to the lower wall sections 36a or 36b (FIG. 6) of the base 11, as the case may be. An upper edge E8 of the lower wall sections 36a or 36b, as the case may be, slides into the aligned slots 44a and 44b to position the platform 18 so its flat top side 18a is substantially horizontal when the stand is resting on its foot elements F1, F2, F3, and F4 to orient the receptacle 13 substantially vertical. The platform 18 may be welded in place. Alternately, the platform 18 is not fixed in place so that it may be detached.

[0055] This configuration of the base 11 and receptacle 13 is essentially symmetrical about the centerline C. Consequently, even with their platforms attached, a plurality of the stands, with their columns and pin elements removed, may be stacked together as shown in FIG. 7. For example, a second essentially identical jack stand 10′ is placed on top of the stand 10. The receptacle 13 of the stand 10 abuts an open lower end E9 of the receptacle 13′ of the stand 10′ and the platform 18 is directly beneath the platform 18′ of the stand 10′. Thus, the stands 10 and 10′ are nested together with the platforms 18 and 18′ aligned. This stacking feature saves space, reducing storage and packaging costs.

[0056] The bottle hydraulic jack 12 is adapted to sit on the flat top side 18a of the platform 18 in an upright, substantially vertical orientation. The jack stand 10 is initially placed, for example, beneath a frame of an automotive vehicle and positioned with respect to the frame so that the locator member 30 will contact a vehicle's frame at a precise location that avoids any damage to the frame when the column 16 of the jack stand is elevated to support the vehicle. As shown in FIG. 4, with the column 16 of the jack stand 10 completely lowered and the piston member 14 of the jack 12 in a completely lowered position, the distance d₁ between the underside 29 (FIG. 2) of the plate member 28 and the top side 18a of the platform 18 is essentially equal to the distance d₂ between the piston head end 14a and the bottom of the jack 12. In other words, with the column 16 completely lowered, the distance d₁ is substantially equal to the height of the vertically oriented jack 12 with its piston 14 completely lowered.

[0057] The jack 12 while on the platform 18 is at least partially received within the hollow interior 32 and is at or near the centerline C. Thus, with the jack 12 so positioned on the platform 18, the piston head end 14a is directly under and adjacent to the underside 29 of the plate member 28. The piston head end 14a engages the underside 29 of the plate member 28 as the piston 14 is elevated in response to the actuation of the piston raising and lowering mechanism 12. The upward vertical movement of the piston 14 raises the column 16, pressing the locator member 30 against the desired precise location along the frame to avoid damaging the frame.

[0058] At a selected elevation, the user manually inserts the pin element 22 into aligned openings in the column 16 and the receptacle 13. When the opening 20a and 20b in the receptacle 13 are aligned with the pair of opening 25a-26a and the pin element 22 is inserted into these four aligned openings, the column 16 is at its lowest elevation. When the opening 20a and 20b are aligned with the pair of opening 25c-26c and the pin element 22 is inserted into these four aligned openings, the column 16 is at its highest elevation as shown in FIGS. 5 and 6. When the opening 20a and 20b are aligned with the pair of opening 25b-26b and the pin element 22 is inserted into these four aligned openings, the column 16 is at an intermediate elevation between the highest and lowest elevations.

[0059] With the column 16 so elevated, the jack's piston 14 is lowered by the user actuating the piston raising and lowering mechanism 12a. The jack 12 may then be removed from the platform 18. Because the locator member 30 contacts the precise location along the frame that avoids bending or otherwise damaging the frame, removal of the jack has no adverse consequences. Simultaneously raising the column 16 as the jack 12 is elevated thus moves the locator member 30 into contact with the precise location along the frame. This solves the problem associate with the two step procedure of first using a jack and then, while the jack is raised and supporting a load, placing a jack stand next to the raised jack to support the load. When the user desires to remove the stand 10, the jack 12 is again placed on the platform and elevated to support the load upon removal of the pin element 22. With the pin element 22 removed the user actuates the piston raising and lowering mechanism 12a to lower the column 16 to the position shown in FIG. 4.

[0060] FIGS. 8 through 12

[0061] In the embodiment shown in FIGS. 8 through 12, the jack stand 10a is of similar pyramid shape to that of the stand 10, but its base 11a is bifurcated into two sections A and B, which are substantially mirror images of each other. The receptacle 13 is used with this stand 10a but is detachably connected by bolts 42 and 43 to the upper end E10 of the stand 10a. The receptacle 13 includes aligned pairs of orifices 40a (FIG. 8) and 40b (FIG. 8A) and 41a (FIG. 8) and 41b (FIG. 8A) beneath the aligned opening 20a (FIG. 8A) and 20b (FIG. 8). The bolt 42 extends through the aligned orifices 40a and 40b and the bolt 43 extends through the aligned orifices 41a and 41b. Nuts 44 and 45 respectively attached to the ends of the bolts 42 and 43 secure the sections A and B to the receptacle 13 in a manner allowing these sections to pivot about the bolts. The lower ends E11a and E11b of the sections A and B are thus moveable relative to each other to increase and decrease the height of the stand 10a. These ends E11a and E11b have apertures 50 (FIG. 8) therein that enable removable pins 51 to detachably connect a pair of braces 46 and 48 to these ends. As shown in FIGS. 9 through 12, the braces 46 and 48 are on opposite sides of the stand 10a and they are selectively positioned to control the distance between the lower ends E11a and E11b to either increase or decrease the height of the base 11a. Each of these braces 46 and 48 has at its one end a hole 46a and 48a, as the case may be, and at its opposed end a series 46b and 48b, as the case may be, of aligned equally spaced apart holes. Pins 51 (FIG. 8) are used to connect the braces 46 and 48 to the lower ends E11a and E11b of the sections A and B.

[0062] FIGS. 13 through 16

[0063] As depicted in FIGS. 13 through 16, the column 16 of the jack stand 10b does not have the openings 26a, 26b, and 26c therein that interact with the pin 22 to hold the raised column in a selected elevated position. Instead, the ratchet mechanism 60 holds the support column 16 in a selected one of plurality of different elevated positions.

[0064] This ratchet mechanism 60 includes a series of teeth 66 along an outer edge 19 of the column 16 that engage a pawl 62 mounted on the receptacle 13 to rotate. A manually operated handle 64 connected to the pawl 62 controls the direction of rotation of the pawl. With the handle 64 in the position shown in solid lines, the pawl 62 may only rotate in a counter-clockwise direction as shown in FIG. 16. Thus, as the piston 14 of the jack 12 is raised, the column 16 is lifted with the pawl 62 passing over the teeth until the desired elevation is attained. At this desired elevation, the pawl 62 moves between a pair of adjacent teeth 66a and 66b (FIG. 16) and engages the upper tooth 66a of these adjacent teeth, holding the column 16 in the selected elevated position. The jack 12 is now removed from the platform and the column 16 being held by the pawl 62 remains in the selected elevated position until lowered.

[0065] When the column 16 is to be lowered, the jack 12 is again placed on the jack platform 18, and the handle 64 is manually moved in the position shown in dotted lines in FIG. 16. This enables the pawl 62 to rotated in a clockwise direction as shown in FIG. 16. With the head end 14a of the piston 14 engaging the underside of the plate member 28 and the handle 64 in the dotted line position, the pawl 62 moves past the teeth 66 along the descending column 16 as it is lowered simultaneously with the piston by actuating the piston raising and lowering mechanism 12a.

[0066] FIGS. 17 through 19.

[0067] As depicted in FIGS. 17 through 19, an embodiment is disclosed in which the column 16 (passing through the receptacle 13) includes an additional column portion 16′ (or, first rod) configured to slide within the column 16 (or, second rod), thus providing a telescoping column. In another aspect, the hydraulic jack may also have an additional piston portion 14′ configured to slide within the piston 14, thus providing a telescoping piston which is known in the field of hydraulic jacks. These telescoping features have the advantage of permitting the jacking system, which includes both the hydraulic jack and the jack stand, to be given a much shorter vertical height than the previous embodiments—and yet be capable of elevating loads by a distance comparable with the previous embodiments. This advantage is important in situations where the load to be lifted is close to the ground, but must be lifted to a height sufficient for a person to crawl underneath. Thus, if a large SUV is to be elevated, a jacking system of the previous embodiments may be suitable, but if a sedan automobile with an undercarriage close to the ground is to be lifted, it may be necessary to use the present embodiment to achieve an adequate clearance space after lifting.

[0068] In one aspect of this embodiment, two separate ratchet mechanisms may be used. A first ratchet mechanism 60 is similar to that used in previous embodiments for holding the column 16 in fixed relation to the base 11. The first ratchet mechanism includes teeth 66 on the column 16, a lever 64 for setting the direction of the ratchet movement, and a pawl 62 for insertion between the teeth to hold the column 16 in fixed relation to the base 11. A second ratchet mechanism 60′ is provided to permit the additional column portion 16′ to slide to selectable positions in relation to the column 16 itself. The second ratchet mechanism includes a second set of teeth 66′ on the additional column portion 16′, a second lever 64′ for setting the direction of relative movement between the two column portions 16, 16′ and a second pawl 62′ (FIG. 19) for insertion between the second set of teeth 66′ to hold the additional column portion 16′ in relation to the lower column 16.

[0069] It will be appreciated that elevating the telescoping piston into contact with the underside of the plate member 28, the upper side of which may be in contact with a load, and then further upwards to lift the load, will cause the column 16 and additional column portion 16′ to be raised also. An upward load will be applied, via the plate member 28, to the additional column portion 16′ (first rod), which will in turn pull upwardly on the column 16 (second rd). As the column 16 and the additional column portion 16′ are raised, the two pawls 62, 62′ will fall in between the sets of teeth 66, 66′ to form a barrier to the retraction of the jack stand. It will be appreciated that the rate of lifting the column 16 and additional column portion 16′ in relation to each other will depend on the relative friction and drag applied by the two ratchet mechanisms, but that ultimately the column 16 and additional column portion 16′ are extendable to their full extent without manual intervention with the ratchet mechanisms 60 and 60′. Thus, when the operator is satisfied with the elevation of the load, he may simply terminate actuating the hydraulic jack. If the hydraulic jack slowly dissipates internal hydraulic pressure to allow the upper tip of the piston to fall slightly, the load will transfer to the elevated jack stand 10 which is mechanically held in fixed elevated position by the column 16 and additional column portion 16′ which in turn are held in fixed position in relation to the base 11 by the two ratchet mechanisms 60, and 60′. Finally, when the user wishes to lower the load, the hydraulic jack 12 must be activated to assume the load if pressure has become dissipated, the direction of the ratchet mechanisms reversed by setting the handles 64, 64′, and the hydraulic jack slowly lowered by manually releasing hydraulic pressure.

[0070] In the present embodiment, it may be convenient to mount the jack stand and the hydraulic jack 12 on a stand 18 configured to hold the jack stand and hydraulic jack in fixed relation to each other, with the axis C1 of the column and the elongate axis of the piston being not co-axial. This aspect conveniently permits the piston to engage with the overhanging plate member 28 of the jack stand when the piston is elevated.

[0071] The above presents a description of the best mode contemplated of carrying out the present invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains to make and use this invention. This invention is, however, susceptible to modifications and alternate constructions from that discussed above which are fully equivalent. Consequently, it is not the intention to limit this invention to the particular embodiment disclosed. On the contrary, the intention is to cover all modifications and alternate constructions coming within the spirit and scope of the invention as generally expressed by the following claims, which particularly point out and distinctly claim the subject matter of the invention: