MECHANISM FOR OPERATING A RAILCAR DISCHARGE GATE ASSEMBLY

Abstract

A mechanism for operating a discharge gate assembly mounted on a railcar. The gate assembly including a frame defining a discharge opening, a door slidably positioned on the frame for a generally horizontal range of movements between a closed position and an open position. An operating shaft assembly is mounted on the frame for rotation about a fixed axis and is operably coupled to the door such that the door moves in response to rotation of the operating shaft assembly. The mechanism for operating the discharge gate assembly includes a mount carried by and with the railcar and an actuator carried by the mount outside a range of travel of the slidable door. A force transfer mechanism is operated by the actuator for rotating the operating shaft assembly to slidably move the door between the closed and open positions in response to operation of the actuator.

Claims

1. A mechanism for operating a discharge gate assembly mounted on a railcar, with said gate assembly including a frame defining a discharge opening, a door slidably positioned on said frame for generally horizontal range of movements between a closed position wherein said door closes said discharge opening and an open position wherein said door is disposed to one side of said opening, an operating shaft assembly mounted on said frame for rotation about a fixed axis, with said operating shaft assembly being operably coupled to said door, said operating mechanism comprising: a mount carried by and with said railcar; an actuator carried by said mount outside a range of travel of said slidable door; and a force transfer mechanism operated by said actuator for rotating said operating shaft assembly to slidably move said door between said closed and open positions in response to operation of said actuator.

2. The railcar discharge gate assembly operating mechanism according to claim 1, wherein said actuator is carried by said mount in a substantially horizontal disposition.

3. The railcar discharge gate assembly operating mechanism according to claim 1, wherein said actuator includes a driver having one end operably joined to said mount and a second linearly distendable end joined to said force transfer mechanism.

4. The railcar discharge gate assembly operating mechanism according to claim 1, wherein said force transfer mechanism includes at least one of a chain or belt arranged for movements in a loop in both forward and backward directions.

5. The railcar discharge gate assembly operating mechanism according to claim 1, wherein said force transfer mechanism includes a first chain or belt arranged in a loop and entrained about first and second linearly spaced members carried by said mount for movements in both forward and backward directions and a second chain or belt arranged in a continuous loop and entrained about said first member and the axis of said operating shaft assembly for imparting rotation to said operating shaft assembly and movements to said slide door upon actuation by said actuator.

6. The railcar discharge gate assembly operating mechanism according to claim 1, wherein said mount and said actuator include cooperating instrumentalities for limiting displacement of said actuator during operation of said railcar discharge gate assembly operating mechanism.

7. A mechanism for operating a discharge gate assembly mounted on a railcar, with said gate assembly including a frame defining a discharge opening, a door slidably positioned on said frame for a range of movements between a closed position wherein said door closes said discharge opening and an open position wherein said door is disposed to one side of said opening, an operating shaft assembly mounted on said frame for rotation about a fixed axis, with said operating shaft assembly being operably coupled to said door, said operating mechanism comprising: a mount carried by and with said railcar; a power source on said railcar; an actuator carried by said mount outside a range of travel of said slidable door, with said actuator having a power source; circuitry arranged between said power source and said actuator for controlling operation of said actuator; and a force transfer mechanism operated by said actuator for rotating said operating shaft assembly to slidably move said door between said closed and open positions in response to operation of said actuator.

8. The railcar discharge gate assembly operating mechanism according to claim 7, wherein said actuator is carried by said mount in a substantially horizontal disposition.

9. The railcar discharge gate assembly operating mechanism according to claim 7, wherein said actuator comprises one of at least: a hydraulic cylinder; a pneumatic cylinder; and, an electric linear actuator.

10. The railcar discharge gate assembly operating mechanism according to claim 7, wherein said actuator includes a linearly distendable pneumatic cylinder, with said circuitry being configured to selectively control said pneumatic cylinder, and with said circuitry including an airflow valve configured to control the air supplied to said pneumatic cylinder.

11. The railcar discharge gate assembly operating mechanism according to claim 10, wherein said air flow valve has: a first operating position providing an airflow to said pneumatic cylinder to positively move said slide gate in first direction; a second operating position providing an airflow to said pneumatic cylinder to positively move said slide gate in a second direction, opposite from said first direction; and, a third operating position restricting airflow from said pneumatic cylinder.

12. The railcar discharge gate assembly operating mechanism according to claim 10, wherein said airflow valve is biased toward said third operating position.

13. The railcar discharge gate assembly operating mechanism according to claim 7, wherein said force transfer mechanism includes at least one of a chain or belt arranged for movements in a loop in both forward and backward directions.

14. The railcar discharge gate assembly operating mechanism according to claim 7, wherein said force transfer mechanism includes first and second linearly spaced members respectively carried by said mount for rotation about first and second fixed axes, a first chain or belt arranged in a loop and entrained about first and second spaced members for movements in both forward and backward directions, and a second chain or belt arranged in a loop and entrained about said first member and the axis of said operating shaft assembly for imparting movements to said slide door.

15. The railcar discharge gate assembly operating mechanism according to claim 7, wherein said mount and said actuator include cooperating instrumentalities for limiting displacement of said actuator during operation of said railcar discharge gate assembly operating mechanism.

16. A mechanism for operating a discharge gate assembly mounted on a railcar, with said gate assembly including a frame defining a discharge opening, a door slidably positioned on said frame for generally horizontal range of movements between a closed position wherein said door closes said discharge opening and an open position wherein said door is disposed to one side of said opening, an operating shaft assembly mounted on said frame for rotation about a fixed axis, with said operating shaft assembly being operably coupled to said door, said operating mechanism comprising: a drive mechanism carried by and with said railcar and which is operably coupled to said sliding door through said operating shaft assembly and configured to allow movement of said slide door between the closed and open positions thereof; and a pneumatic actuator coupled to said drive mechanism and operable to power said drive mechanism so that slide door is forcibly moved between the closed and open positions, with said pneumatic actuator being selectively coupled to a source of compressed air on said railcar.

17. The railcar discharge gate assembly operating mechanism according to claim 16, further including a mount carried by said railcar, and wherein said pneumatic actuator is carried on said mount in a substantially horizontal position.

18. The railcar discharge gate assembly operating mechanism according to claim 16, wherein said actuator includes a driver having one end joined to said mount and a second linearly distendable end joined to said drive mechanism.

19. The railcar discharge gate assembly operating mechanism according to claim 16, wherein said drive mechanism includes at least one of a chain or belt arranged for movements in a loop in both forward and backward directions.

20. The railcar discharge gate assembly operating mechanism according to claim 17, wherein said drive mechanism includes a first chain or belt arranged in a loop and entrained about first and second linearly spaced members carried by said mount for movements in both forward and backward directions and a second chain or belt arranged in a loop and entrained about said first member and the axis of said operating shaft assembly for imparting rotation to said operating shaft assembly and movements to said slide door upon actuation by said pneumatic actuator.

21. The railcar discharge gate assembly operating mechanism according to claim 17, wherein said mount and the second linearly distendable end of said pneumatic actuator include cooperating instrumentalities for limiting displacement of said pneumatic actuator during operation of said drive mechanism.

22. The railcar discharge gate assembly operating mechanism according to claim 17, wherein said pneumatic actuator is selectively coupled the source of compressed air on said railcar through valve structure which controls directional operation of said actuator on said railcar.

Description

DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a side elevational view of a railroad hopper car embodying principals and teachings of this invention disclosure;

[0021] FIG. 2 is an enlarged fragmentary side elevational view of that area encircled in phantom lines in FIG. 1;

[0022] FIG. 3 is a perspective view of one form of railcar gate assembly with which the present invention disclosure finds utility;

[0023] FIG. 4 is an end view of the railcar gate assembly illustrated in FIG. 3;

[0024] FIG. 5 is a side view of the railcar gate assembly illustrated in FIG. 3

[0025] FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 2;

[0026] FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 2;

[0027] FIG. 8 is an enlarged fragmentary side elevational view of one form of mechanism for operating a discharge gate assembly according to the present invention disclosure

[0028] FIG. 9 is an enlarged fragmentary view of that area encircled in dash lines in FIG. 1

[0029] FIG. 10 is an enlarged sectional view taken along line 10-10 of FIG. 8;

[0030] FIG. 11 is an enlarged side elevational view of that area encircled in phantom lines in FIG. 8;

[0031] FIG. 12 is an enlarged view of that area encircled in phantom lines in FIG. 10; and

[0032] FIG. 13 is a schematic representation of one form of circuitry for controlling operation of the railcar discharge gate assembly operating mechanism.

DETAILED DESCRIPTION

[0033] While this invention disclosure is susceptible of embodiment in multiple forms, there is shown in the drawings and will hereinafter be described a preferred embodiment, with the understanding the present disclosure is to be considered as setting forth an exemplification of the disclosure which is not intended to limit the disclosure to the specific embodiment illustrated and described.

[0034] Referring now to the drawings, wherein like reference numerals indicate like parts throughout the several views, there is shown in FIG. 1 a railroad hopper car, generally designated by reference numeral 10. Car 10 includes a walled enclosure or hopper 12 wherein materials or commodity can be stored and shipped. The hopper or enclosure 12 has a generally rectangular configuration, in plan, toward an upper end thereof and includes upstanding rigid side walls 16 and 18 rigidly joined to upstanding end walls 20 and 22 (FIG. 1). The walled enclosure 12 is carried on a conventional mobile frame 24. Opposed ends of the walled enclosure or hopper 12 and frame 24 are supported in a well known manner by trucks 28 shown pictorially in FIG. 1. As shown, wheels of each truck 28 engage and roll over a pair of laterally spaced rails 29, 29 on a road bed RB.

[0035] In the embodiment illustrated for exemplary purposes in FIG. 1, a bottom 30 of the walled enclosure or hopper 12 is provided with at least two longitudinally spaced discharge areas 32 and 34 from whence material in the hopper 12 is gravitationally discharged. It will be appreciated, however, the bottom 30 of the walled enclosure 12 can be provided with more than two discharge areas without detracting or departing from the novel spirit and broad scope of this invention disclosure. In the illustrated embodiment, the discharge areas 32 and 34 are substantially identical relative to each other and, thus, only discharge area 32 will be discussed in detail.

[0036] Each discharge area at the bottom of hopper 12 includes a discharge opening 36 for allowing or permitting material in the hopper 12 to be rapidly and gravitationally discharged in a controlled manner therefrom. In the embodiment illustrated by way of example in FIGS. 1 and 2, each discharge opening 36 defined by hopper 12 has a generally rectangular marginal edge configuration.

[0037] An appropriately sized gate or door assembly 40 is arranged in operable combination with each discharge opening comprising the respective discharge area at the bottom of the walled enclosure 12. Again, it should be appreciated, the number of discharge gates arranged in operable combination with the hopper 12 will be a function of the number of discharge openings associated with each discharge area on the hopper 12.

[0038] In the illustrated embodiment, the gate assembly operably associated with the discharge area 32 is substantially identical relative to the discharge gate assembly operably associated with the discharge area 34. In one form, each gate assembly is a conventional 1342 inch gate assembly sold by Miner Enterprises, Inc. under Model Number MICE 10513; although other conventional gate assemblies would equally suffice. Preferably, each gate assembly is disposed to gravitationally discharge commodity from the hopper 12 between the rails 29, 29 (FIG. 1). In the illustrated embodiment, the gate assembly 40 for each discharge area is preferably disposed in substantially longitudinally aligned relation relative to each other.

[0039] In the illustrated embodiment, and since the gate assembly associated with each discharge area 32, 34 on car 10 are substantially similar to each other, only one gate assembly will be described in detail. As illustrated by way of example in FIGS. 3, 4 and 5, each gate assembly includes a rigid frame 42 preferably defining a generally rectangular discharge outlet 43 (FIG. 3) arranged in generally registry or material receiving relation with one of the discharge openings comprising one of the discharge areas on car 10 (FIG. 2). Frame 42 of gate assembly preferably includes four frame members 44, 45, 46 and 47 rigidly interconnected to each other in a generally rectangular pattern.

[0040] To facilitate mounting each gate assembly to suitable structure on hopper 12, each frame member 44, 45, 46 and 47 preferably terminates toward an upper end in an apertured and generally horizontal flange 48 extending outward and away from the discharge outlet of the respective gate. The apertured horizontal flanges 48 on the frame members 44, 45, 46 and 47 of each gate assembly are arranged in generally coplanar relationship relative to each other. Although the method of interface of each gate assembly with hopper 12 is illustrated as being with a generally horizontal flange 48, it will be appreciated the flanges 48 can also be slopped or angled to substantially correspond with the downward slope or angle of the depending chute wall of the hopper 12 (FIG. 1) leading to the respective discharge opening and be suitably secured thereto, as by welding or the like, without detracting or departing from the spirit and scope of this invention disclosure.

[0041] Each gate assembly furthermore includes a gate or slide door 50 mounted on the respective frame below the flanges 48 for sliding movement preferably in a generally horizontal path of travel or range of movements. The slide door 50 is movable anywhere between a first or closed position, wherein the door closes the discharge opening of the respective gate assembly, and a second or open position. In the open position, the slide door is disposed to one side of the respective discharge opening. When the slide door is in the second or open position, material is permitted to gravitationally exit or pass through the respective discharge outlet defined by the associated gate assembly from the respective discharge opening in the hopper 12. The materials gravitationally discharged from the hopper 12 are likely to predominately fall between the rails.

[0042] Each gate assembly further includes a suitable drive apparatus 54 for moving the respective slide door 50 (FIG. 3) thereof anywhere between and to the first or closed position and the second or open position and relative to the discharge outlet of the respective gate assembly. In one form, drive apparatus 54 includes an elongated operating shaft assembly 56 mounted on or carried by the frame 42 for rotation about a fixed axis 57. Typically, the operating shaft assembly 56 rotates between two and three complete revolutions about axis 57 as the door 50 moves between fully closed and fully open positions. Of course, and as will be appreciated, the operating shaft assembly 56 can rotate more or less about its fixed axis 57 as the slide door 50 moves between fully closed and fully open positions without detracting or departing from the spirit and broad scope of this invention disclosure.

[0043] In at least one embodiment, the operating shaft assembly 56 includes an elongated drive shaft 58 mounted for rotation on the frame 42 of the respective gate assembly about the fixed axis 57. A capstan 59 is arranged at opposed ends of and, in the illustrated embodiment, in non-rotatable relationship with the drive shaft 58. In the embodiment illustrated in FIGS. 3, 4 and 5, the operating shaft assembly 56 associated with each gate assembly is operably coupled to and moves the respective slide door thereof between positions and relative to the discharge outlet of the respective gate assembly as a result of rotation thereof about axis 57.

[0044] In the embodiment illustrated by way of example in FIGS. 3 and 4, a mechanism 60 is provided on each gate assembly for converting rotational movements of the operating shaft assembly 56 into linear movements of the slide door 50 (FIG. 3) of the respective gate assembly. In one form, such mechanism 60 includes a conventional rack and pinion assembly. It will be appreciated, however, other devices and/or mechanisms can be used for converting rotational movements of the operating shaft assembly 56 into linear movements of the slide door 50 of the respective gate assembly without detracting or departing from broad spirit and scope of this invention disclosure.

[0045] In the embodiment shown by way of example in FIG. 4, the rack and pinion assembly of each gate assembly preferably includes a pair of laterally spaced racks 62, 62 provided on an underside 51 of the respective slide door 50 to be moved along with a pair of laterally spaced pinion gears 64, 64 arranged in intermeshing relationship with the racks 62, 62, respectively. The pinion gears 64, 64 are arranged on the drive shaft 58 such that rotation of the operating shaft assembly 56 of the respective gate assembly results in linear displacement of the respective slide door in a direction dependent upon the rotational direction of shaft 58 about axis 57.

[0046] In the embodiment illustrated by way of example in FIG. 5, each gate or door assembly 40 furthermore includes a lock assembly 68 for maintaining the slide door 50 (FIG. 3) in a closed position especially as the railcar 10 (FIG. 1) moves between locations. In one form, the lock assembly 68 embodies the teachings and principals of that disclosed in U.S. Pat. No. 5,829,359 to J. J. Dohr, et al.; the applicable portions of which are incorporated herein by reference.

[0047] According to this invention disclosure, each gate or door assembly 40 on hopper 12 furthermore includes a drive mechanism, generally indicated by reference numeral 70, for operating the gate assembly 40. In at least one embodiment illustrated by way of example in FIG. 2, the operating mechanism 70 associated with one gate or door assembly 40 is disposed or arranged to one lateral side of car 10 while the operating mechanism associated with the other gate or door assembly is disposed or arranged to an opposite lateral side of the car 10. Preferably, the operating mechanisms are substantially identical and, thus, only one operating mechanism will be described in detail.

[0048] In that embodiment illustrated by way of example in FIG. 6, each operating mechanism 70 has an elongated base or mount 72 carried by and with the railcar 10 (FIG. 1). As such, each operating mechanism 70 moves with the car 10 as the car 10 moves between locations. Preferably, and as illustrated in FIG. 2, mount 72 is carried in a substantially horizontal disposition. In one embodiment, mount 72 is suspended by suitable brackets 74 extending from either the car frame 24 or from hopper 12 on car 10. In the embodiment illustrated by way of example in FIGS. 6 and 7, mount 72 has a generally C-shaped cross-sectional configuration and includes a rigid back wall 76 with top and bottom walls 77 and 78, respectively, extending in the same direction relative to each other outwardly from the back wall 78 so as to define a protective cavity 79 therebetween. As illustrated, and toward opposed ends, the top and bottom walls 77 and 78 of mount 72 are rigidly interconnected by vertical braces 80 and 82.

[0049] Returning to FIG. 2, an actuator 84 is carried by the mount or base 72 outside a range of travel of the slidable door 50 (FIG. 3) of the respective gate assembly. The actuator 84 is preferably carried by the mount 72 in a substantially horizontal position and, preferably, within the protective cavity 79 defined by mount 72. In the embodiment t illustrated by way of example in FIG. 8, the actuator 84 of each operating mechanism has one end 86 joined or operably coupled to the base or mount 72 and a second linearly distendable end 88. In a preferred embodiment, the actuator 84 comprises one of at least: a pneumatic cylinder, a hydraulic cylinder; and, an electric liner actuator. In the embodiment illustrated by way of example, the actuator 84 has a stroke length of at least 28.5 inches.

[0050] As shown by way of example in FIG. 8, a force transfer or drive mechanism 90 is operated by the actuator 84 for rotating the operating shaft assembly 56 (FIG. 3) of the respective gate assembly whereby slidably and positively moving the door 50 (FIG. 3) of the respective gate assembly between closed and open positions in response to operation of the actuator 84. Preferably, the force transfer mechanism 90 includes at least one of a chain assembly or belt assembly arranged for movements in a loop in both forward and backward directions.

[0051] In the embodiment illustrated in FIGS. 6 and 9, the chain assembly or belt assembly of the force transfer mechanism 90 includes a first chain or belt 94 arranged in a loop and entrained about first and second horizontally spaced members 96 and 98, respectively, for movements in both forward and backward directions. As illustrated in FIGS. 7 and 8, the first and second horizontally spaced members 96 and 98, respectively, are arranged for free rotation about fixed axes 97 and 99, respectively, and are carried by mount 72. As shown in FIGS. 6 and 8, in a preferred embodiment, the chain assembly or belt assembly 92 of the force transfer mechanism 90 furthermore includes a second chain or belt 104 arranged in a loop and entrained about the rotatable member 98 and the axis 57 of the operating shaft assembly 56 (FIG. 9) for imparting rotation to the operating shaft assembly 56 and movements of the slide door 50 upon actuation of the actuator 84.

[0052] In the embodiment illustrated by way of example in FIG. 6, member 98 about which a portion of the first chain or belt 94 is entrained includes two side-by-side or laterally adjacent portions 98a and 98b. A portion of the first chain or belt 94 is entrained about portion 98a of member 98 while a portion of the second chain or belt 96 is entrained about portion 98b of member 96. As such, movements of the first chain or belt 94 by actuator 84 will likewise be transferred to movements of the second chain or belt 104.

[0053] As shown in FIGS. 2 and 9, another member 105 is arranged in operable combination with the operating shaft assembly 56. In the illustrated embodiment, member 105 is non-rotatably carried by the respective capstan 59 (FIG. 3) on the operating shaft assembly 56. A portion of the second chain or belt 104 is entrained about member 105 such that either forward or backward movements of the second chain or belt 104 will translate into rotation of the operating shaft assembly 56 about axis 57 which results in sliding movements of the door 50 upon actuation of the actuator 84. In this embodiment, the pitch diameters of members 98 and 105 have a ratio of about 2:1.

[0054] The mount 72 and the actuator 84 preferably define cooperating instrumentalities 110 for limiting displacement of the second end of the actuator 84 during operation of the railcar discharge gate assembly operating mechanism 70. In the embodiment shown by way of example in FIGS. 10 and 11, such cooperating instrumentalities 110 include a connector 112 for operably coupling the second linearly distendable end 88 of actuator 84 to the force transfer mechanism 90. As shown by way of example in FIGS. 10 and 12, a vertical extension 114 on the connector 112 projects through an elongated slot or channel 116 which, in the illustrated embodiment, is defined by the top or upper wall 77 of the mount 72. In a preferred embodiment shown by way of example in FIG. 11, a slide plate 118, having a width greater than slot or channel 116 (FIG. 10) is carried by and moves with the extension 114 and underlies the top or upper wall 77 of the mount 72 to limit unwarranted displacement of actuator 84.

[0055] In the embodiment illustrated by way of example in FIG. 12, the cooperating instrumentalities 110 for limiting displacements of the second end of the actuator 84 during operation of the railcar discharge gate assembly operating mechanism 70 can further include material 120 operably disposed between the extension 114 and mount 72 as well as between the slide plate 118 and mount 72 to promote endwise sliding movements of the connector 112 relative to mount 72. In one form, material 120 includes ultra-high molecular weight plastic or nylon materials for establishing a relative low coefficient of friction between the extension 114 on connector 112 and mount 72 as well as between the slide plate 118 and mount 72 whereby promoting endwise sliding movements of the connector 112 relative to mount 72.

[0056] Turning now to FIG. 13, there is schematically represented circuitry 130 for controlling operation of each railcar discharge gate assembly operating mechanism 70. Circuitry 130 is arranged between a suitable power source 132 on the railcar 10 and the actuator 84 of the drive mechanism 70 operably associated with each gate assembly on car 10. In the embodiment illustrated by way of example in FIG. 14, the power source 132 is a suitable source of compressed air on railcar 10.

[0057] In the embodiment illustrated by way of example in FIG. 13, circuitry 130 further includes valve structure 134 for controlling the directional operation of the actuator 84 operably associated with each operating mechanism 70 for each gate or door assembly 40 (FIG. 1) on railcar 10. In the embodiment illustrated by way of example in FIG. 14, and since the railcar 10 illustrated by way of example has two gate or door assemblies 40 operably associated with hopper 12 (FIG. 1), the valve structure 134 used to control the directional operation of the actuator 84 associated with each operating mechanism 70 for each gate or door assembly 40 (FIG. 1) on railcar 10 includes two valve assemblies 136, 136. Suffice it to say, valve structure 134 is preferably configured such that the actuator 84 of each operating mechanism 70 positively maintains the slide door or gate 50 of each gate assembly (FIG. 3) in a closed position until the valve structure 134 is operated to positively move the slide door or gate 50 of the respective gate assembly toward an open position.

[0058] In the embodiment illustrated by way of example in FIG. 13, the actuator 84 operably associated with each operating mechanism 70 for each gate or door assembly 40 (FIG. 1) on railcar 10 is a pneumatic cylinder. As such, the valve structure 134 includes a conventional air flow valve configured to control the air supplied to the pneumatic cylinder of each operating mechanism 70. As will be readily understood to those skilled in the art, the air flow valve has: a first operating position providing an airflow to said pneumatic cylinder to positively move the slide gate in first direction; a second operating position providing an airflow to the pneumatic cylinder to positively move the slide gate in a second direction, opposite from the first direction; and, a third operating position restricting airflow from the pneumatic cylinder.

[0059] In one form of the invention disclosure, the valve structure 134 is structured to furthermore allow for manual operation of each gate assembly 40. It is within the spirit and scope of this invention disclosure, however, to furthermore allow valve structure 134 to be remotely controlled whereby facilitating discharge of material from the railcar 10 (FIG. 1) while the car 10 is moving along the rails.

[0060] From the forgoing, it will be observed numerous modifications and variations can be made and effected without departing or detracting from the true spirit and novel concept of this invention disclosure. Moreover, it will be appreciated, the present disclosure is intended to set forth exemplifications which are not intended to limit the disclosure to the specific embodiments illustrated and discussed. Rather, this disclosure is intended to cover by the appended claims all such modifications and variations as fall within the spirit and scope of the claims.