US3062398A

US3062398A - Sanitary manhole assembly

Info

Publication number: US3062398A
Application number: US73635A
Authority: US
Inventors: Myron G Kordes
Original assignee: Standard Steel Works Inc
Current assignee: Standard Steel Works Inc
Priority date: 1960-12-05
Filing date: 1960-12-05
Publication date: 1962-11-06
Anticipated expiration: 1979-11-06

Description

Nov. 6, 1962 M. G. KORDES SANITARY MANHOLE ASSEMBLY 2 Sheets-Sheet 1 Filed Dec. 5, 1960 III. 10.14

MM M 6 W M Nov. 6, 1962 Filed Dec. 5, 1960 M. e. KORDES 3,062,398

SANITARY MANHOLE ASSEMBLY 2 Sheets-Sheet 2 INVENTOR. Myra/7 & Kora e5 ATTQRN 5.

ilnite States Patent tine 3,062,398 SANITARY MANHOLE ASSEMBLY Myron G. Kordcs, Kansas City, Mo., assignor to Standard Steel Works, Inc., Kansas City, Mo., a corporation of Missouri Filed Dec. 5, 1969, Ser. No. 73,635 13 Claims. (Cl. 220-29) This invention relates to closure for access openings in materials-containing tanks and more particularly, tanks utilized for the transfer and storage of liquid food products requiring that the tanks and closures therefor be maintained in a sanitary condition to prevent the formation of germs therein and the contamination of the products carried thereby.

It is the primary object of this invention to provide a closure member for closing an access opening in a tank adapted to contain liquid food products to seal the tank from the contaminating effects of foreign objects present in the atmosphere and to prevent the formation of germs therein to thereby maintain the contents of the tank in a sanitary condition to comply with recognized standards of health.

Another important object of this invention is the provision of a closure member for the access opening of a materials-containing tank, which closure member may be easily and quickly shifted so as to permit ready access to the opening and to facilitate the rapid cleaning of the closure member to maintain the same and thereby the interior of the tank in a substantially sanitary condition.

Still another important object of this invention is to provide a closure member for an access opening in a tank, which member includes a pair of relatively shiftable closure elements adapted to be super-imposed over the opening, the upper of said elements serving as a dust cover and the lower of said elements sealing the opening, wherein the tank is sufiiciently insulated from the introduction of contaminating effects even when the upper of the elements is shifted to a position clearing the opening.

Yet another important object of the present invention is the provision of means on the relatively shiftable elements for interconnecting the same and for limiting the relative movement thereof, whereby the elements are effectively secured togther so as to form an integral unit manipulable for easy access to the interior of the tank to which the elements are operably coupled.

Other important objects of this invention relate to the provision of structure including a pair of relatively shiftable, U-shaped linkages interconnecting the closure elements, whereby one of the elements may be shifted relative to the other elements; to the provision of projections on opposed faces of the elements, whereby said linkages may be secured to the corresponding elements; to the pro vision of hinge means on the upper element and the tank, whereby the upper element and thereby the lower element may be swingable relative to the tank to permit access to the opening in the latter; to the provision of lever means for maintaining the elements in a position closing the opening and the tank; and to the provision of bearing means on the lever means for engaging the upper element and urging the same downwardly into engagement with the lower element when the latter closes said opening.

Other objects of this invention will become apparent as the following specification progresses, reference being made to the accompanying drawings wherein:

FIG. 1 is a fragmentary, cross-sectional plan view of the tank closure member which is the subject of this invention;

FIG. 2 is a cross-sectional, side elevational view of the FIG. 1;

FIG. 3 is a fragmentary, cross-sectional side elevational view of subject invention illustrating the pair of closure elements and the lever means forming a part thereof;

FIG. 4 is an enlarged, fragmentary, cross-sectional side and elevational view taken along line 4-4 of FIG. 2;

FIG. 5 is an enlarged, fragmentary view of the sealing gasket and the pressure equalizing means thereon; and

FIG. 6 is a cross-sectional view of the gasket taken along lines 66 of FIG. 5.

The closure member which is the subject of this invention is broadly denoted by the numeral 10 and the same provides a means for closing the open, upper end 12 of an upright, tubular device 14 having a cylindrical sidewall 16. Device 14 is secured to the top wall 18 of a storage tank (not shown) having a circular access opening 26 therein, it being noted that device 14 is secured to wall 13 in communication with opening 20 as by welding or the like. It is contemplated that closure member 10 be utilized with tanks adapted to store and transport liquid food products, which tanks are usually provided with a shell 22 in surrounding engagement to wall 18 and the remainder of the tank so as to present a space 24 between tank and shell wherein insulating material may be placed so as to protect the contents of the tank against extremes of atmospheric temperatures. Shell 22 is provided with an opening aligned with opening 20 so as to permit device 14 to pass through shell 22, it being noted that the upper end 12 of device 14 is spaced above shell 22 as is clear in FIG. 2.

Closure member 16 includes a pair of relatively

shiftable elements

26 and 28 which may be super-imposed over the open upper end 12 of device 14 for closing the latter, a first of said elements, namely element 26 taking the form of a fiat plate having a pair of opposed faces 30 and 32, the second of said elements, namely element 28, taking the form of a concave-convex shell having a concave inner surface 34 and a convex outer surface 36.

Element 26 is provided with an annular flange 38 integral therewith at the outer periphery thereof, which flange 38 is engageable with an annular head 40 forming a part of an annular gasket 42 of resilient material disposed on upper end 12 of device 14. Flange 38 is provided with an arcuate portion 44 which complenentally engages the outer surface of annular head 40 when first element 26 covers the upper open end 12 of device 14, by virtue of which complemental engagement, bead 40 is compressed against upper end 12 of device 14, thus sealing the latter against the entrace therein of foreign objects present in the atmosphere and thereby prevents the formation of germs in the contents carried by the tank to which device 14 is attached. Flange 38 is further provided with a transversely upright portion 46 integral with arcuate portion 44, which upright portion 46 is substantially parallel with and substantially concentric to an annular, upright section 48 of gasket 42 integral with the annular head 40 thereof, it being noted that the outermost extremity of flange 38 is spaced above an annular, transverse section 56 integral with upright section 48 and extending laterally from device 14, as is clear in FIG. 2.

Second element 28 is provided with an annular flange 52 having a transversely arcuate portion 54 substantially overlying arcuate portion 44 and thereby bead 40 when both first and

secondelements

26 and 28 cover the open end 12 of device 14. Flange 52 is further provided with a transversely upright portion 56 which slightly flares outwardly from device 14 and diverges relative to upright portion 46 of flange 38 as the outer most extremity of second element 28 is approached. It is to be noted that when

elements

26 and 28 are disposed on device 14 as in shown in FIG. 2, the outermost extremity of flange S2 of second element 23 engages the normally uppermost surface 58 of transverse section 50 in sealing relationship therewith so that the interengagement between second element 28 with flange 42 further prevents the introduction of foreign objects within the open upper end 12 of device 14, and thereby the interior of the tank to which the latter is attached. In addition, transverse section 50 is permitted to freely flex downwardly under the influence of flange 52 to thereby permit the full compression of bead 40 under the influence of first element 26. It is clear that flange 38 circumferentially engages head 40 and flange 2 circumferentially engages surface 58 when

elements

26 and 28 are disposed in the position shown in FIG. 2. Arcuate portion 54 of flange 52 is provided with a plurality of dimples 60 stamped therein and circumferentially spaced to slightly space the inner surface of arcuate portion 54 of flange 52 above the outer surface of arcuate portion 44 of flange 38 for a purpose hereinafter described.

Hinge means 62 are provided on second element 28, shell 22 and device 14 for swinging second element 28 about a subsatntially horizontal axis toward and away from the open, upper end 12 of device 14 so as to gain access to the latter and thereby the interior of the tank to which the same is attached. Hinge means 62 includes a first U-shaped bracket 64 carried by shell 22 and a second U-shaped bracket 66 carried by second element 28 and mounted for shiftable movement relative to first bracket 64. First bracket '64 is provided with a bight portion 68 secured to the upper surface of shell 22 by a plurality of threaded bolts 70 threadably received in aligned openings in bight portion 68 and the corresponding region of shell 22. To reinforce the connection between first bracket 64 and shell '22, a U-shaped brace 72 is provided and includes a bight 74 underlying the bight 68 of first bracket 64, it being noted that bight 74 is provided with openings for threadably receiving bolts 70 for interconnectnig brace 72 with first bracket 64. The peripheral edge of brace 72 adjacent device 14 is welded to the latter so as to secure first bracket 64 to both shell 22 and device 14.

First bracket 64 is provided with a pair of spaced, upright legs 76 which are provided with aligned openings into which is journaled a shaft 78 spaced above and substantially parallel with bight portion 68 of first bracket 64. The ends of shaft 78 project outwardly from legs 76 as is clear in FIG. 4 for the purpose of mounting second bracket 66 in a manner hereinafter described. Secured to shaft substantially midway between the ends thereof and extending laterally therefrom is an elongated rod 80 having the end thereof spaced from shaft 78 threaded so as to mount an internally threaded wing nut 82 thereon, the latter providing a fastening means for interconnecting

brackets

64 and 66.

Second bracket 66 is provided with a perforated bight portion 84, a pair of spaced, slotted side legs 86 integral with opposed side edges of bight portion 84, and a tab portion 88 secured to an end edge of bight portion 84 and extending away from legs 86 so as to engage the convex outer surface 36 of second element 28. Tab 88 is rigidly secured to surface 36, as by welding, to thereby secure bracket 66 to second element 28. Each leg 86 is provided with a U-shaped slot 90 therein at the extremity thereof spaced from bight portion 84, and slots 90 complementally receive the opposed ends of shaft 78 to permit second bracket 66 and thereby second element 28 to be rotatable relative to first bracket 64 and thereby device 14 about an axis through shaft 78. The threaded end of rod 80 extends through a perforation 92 in bight portion 84 to effectively interconnect

brackets

64 and 66 and thereby provide a fastening means, together with wing nut 82, for maintaining the ends of shaft 78 within slots 90 of legs 86.

Hinge means 62 further provide a means of maintaining

elements

26 and 28 in the position shown in FIG. 2, since by tightening wing nut 82 to a substantial degree, second element 28 is prevented from rotating about the axis of shaft 78 unless a substantially large lifting force is applied thereto to cause the rotation thereof. This is due to the fact that when wing nut 82 is tightened, the ends of shafts 78 are more firmly seated within slot so as to require a proportionately greater force to overcome the sliding friction between the ends of shaft 78 and the adjacent surfaces of slots 90.

Means for interconnecting

elements

26 and 28 include a pair of relatively

shiftable components

94 and 96 each shiftably mounted on a corresponding element and pivotally mounted on the adjacent component to limit the movement of one of the elements relative to the other element.

Components

94 and 96 comprise

U-shaped linkages

98 and 100 respectively, it being noted that linkage 100 is disposed within linkage 98 and the spaced sides 102 of the latter are somewhat shorter in length than are the sides 104 of linkage 100. Sides 102 of linkage )8 are provided with pins 166 rigid thereto at the extremities thereof, it being noted that pins 186 extend outwardly in opposite directions to be received in the perforations of a pair of spaced, perforated ears 108 secured uprightly on upper face 32 of first element 26. In like manner, sides 104 of linkage 100 are provided with pins 110 extending outwardly in opposite directions to be received in a pair of spaced, perforated ears 112 secured to the concave lower face 34 of second element 28. Sides 104 of linkage 100 are further provided with pins 114 intermediate the ends thereof and spaced outwardly in the same direction as pins 110, pins 114 being received in openings in sides 102 of linkage 98 which are aligned therewith so as to mount linkage 100 on linkage 98 for pivotal movement relative thereto. It is clear that by virtue of the pivotal mounting means including

pins

106, 110 and 114 and

ears

108 and 112, second element 28 may be shifted to a limited degree relative to first element 26 when the latter covers the open upper end 12 of device 14 prior to the shifting of first element 26 away from end 12 to gain access to the interior of the tank to which device 14 is attached.

Linkages 88 and 100' are made of a material which is substantially rigid but which is of a nature to impart a certain amount of flexibility to

sides

102 and 104 thereof so that the same may be flexed to permit the insertion of

respective pins

106 and 110 into the perforations of

ears

108 and 112 respectively. Further, pins 114 may be inserted in the openings in sides 102 by flexing the latter and sides 104.

Means are provided on closure member 10 for maintaining second element 28 in substantial engagement with first element 26 when the elements close the upper end 12 of device 14 and comprise a pair of levers 116 swingably mounted on device 14 and provided with bearing means engageable with the convex upper surface of second element 28 to urge the latter into engagement with first element 26. Each lever 116 is provided with a threaded bore 118 which receives the threaded end 120 of an L- shaped support 122, it being clear that the length of support 22 having the threaded end 120 is substantially parallel with the central axis of device 14. The opposite end of support 122 is secured rigidly to device 14 in any suitable manner, such as by welding. Lever 116 is provided with a groove 124 therein proximal to the end thereof containing bore 118 and a shaft 126 rigidly mounting a roller 128 thereon is journaled in opposed faces of groove 124 to permit roller 128 to be rotatable about the longitudinal axis of shaft 126. Roller 128 is adapted to engage the arcuate portion 54 of annular flange 52 integral with second element 28 when lever 116 is swung about the end of support 122. If the threads of bore 118 and end 120 of support 122 are of the conventional right hand type, and if lever 116 is rotated in a clockwise manner as viewed in FIG. 1, it is clear that lever 116 and thereby roller 128 will advance toward the upper open end 12 of device 14 when lever 116 is so swung. It is sufficiently clear that when lever 116 is swung in the clockwise manner, roller 128 engages arcuate portion 54 of annular flange 52 to urge the latter and thereby second element 28 into engagement with first element 26. As long as roller 128 engages arcuate portion 54 of annular flange 52, second element 28 remains in a fixed position relative to first element 26 and lever 116 must be swung so as to move roller 128 out of engagement with arcuate portion 54 before second element 28 may be shifted relative to first element 26.

To facilitate the shifting of

elements

26 and 28 relative to device 14, handles 130 and 132 are secured to upper face 32 of first element 26 and convex outer surface 36 of second element 28, respectively.

Valve means are also provided in closure member to maintain the pressures within the tank to which mem ber 10 is secured substantially equal to the pressure of the atmosphere surrounding the tank and closure member 10. Such valve means, forming no part of the instant invention, include a convex-concave part 134 which is integral with first element 26, and a channel shaped disc 136 interconnected with part 134 by means of a connective 138 extending through aligned openings in part 134 and disc 136, it being noted that connective 138 is rigid to the central portion 140 of disc 136 and the end of connective 138 inserted through the opening in part 134 is retained therein by a key 142 in the manner shown in FIG. 1. Disposed between part 134 and disc 136 is an initially flat, resilient, annular diaphragm 144 in sealing engagement with the central portion 140 of disc 136 and the connection of part 134 with the remainder of first element 26. Disc 136 is mounted in a manner so as to present a passage 146 between the lower face 30 of first element 26 and the upper peripheral edge of annular flange 148 integral with disc 136. When the pressure within the tanks to which closure member 10 is attached increases to a value above that of the atmosphere, the air passes through passage 146 to the under side of diaphragm 144 whereupon the latter is raised out of engagement with central portion 140 to permit the air to flow toward connective 138 and out through an opening 150 centrallydisposed in diaphragm 144. The air particles then flow out through perforations 152 in part 134 and thence into the region between first andsccond'

elements

26 and 28. By virtue of the dimples 60 in annular flange 52 of second element 28, the air is permitted to flow out .of the space between the elements and, further, by virtue of the resilient nature of gasket 42, the air. forces the. transverse section 50 of gasket 40 to move out of engagement with the outermost edge of flange 52 to thereby'permit the outward flow of air to equalize the pressure within the tank.

In the event that the pressure within the tank falls below that of the atmosphere, air enters the region be

tween elements

26 and 28 by first entering a region formed by side walls 16 of device 14 and a grooved portion 154 on the inner surface of gasket 42. Since the pressure on the normally outer surface of gasket 42 is less than the pressure against the surface formed by grooved portion 154, gasket 42 is forced out of engagement from device 14 in the region proximal to grooved portion 154 and the air flows through a longitudinal slot 156 formed in gasket 42 above grooved portion 154, whereupon the air flows into the region between

elements

26 and 28 by virtue of the passages therebetween formed by dimples 60. The air then flows through perforations 152 of part 134 and against the upper surface of diaphragm 144 to cause the latter to flex downwardly and out of engagement wtih the connection of part 134 with the remainder of first element 26. The air then flows between part 134 and diaphragm 144 into the passage 146 and finally into the tank therebelow.

When it is desired to gain access to the interior of the tank to which closure member 10 is attached, either for filling the tank or for cleansing the latter,

second element

6, 28 is rotated about the longitudinal axis of shaft 78 until second bracket 66 of hinge means 62 engages the proximal portion of shell 22. Element 28 is thus supported by shell 22 and in a position clearing the top of device 14. It is to be understood that swinging movement of element 28 away from covering relationship to the top of device 14 causes element 26 to be partially lifted out of engagement with gasket 42, since the longitudinal axes of

linkages

98 and 100 become substantially coextensive before bracket 66 engages shell 22. Further swinging of element 28 about the axis of shaft 78 is sufiicient to swing element 26 away from device 14 about an axis through the point of contact of arcuate portion 44 with bead adjacent hinge means 62. The operator of closure member 10 may then manually swing element 26 until the latter is completely disposed within element 28. Access to the tank is thus assured. In FIG. 2 an intermediate position of second element 28 shown by the dashed lines of FIG. 2. By virtue of

linkages

98 and 100, second element is limited to its movement relative to first element 26 and furthermore,

linkages

98 and 100 provide hinge means for mounting first element 26 on second element 28 to thereby guide first element 26 when the same is moved away from the open upper end 12 of device 14.

After access has been gained to the interior of the tank, first element 26 is moved to a position closing the end 12 of device 14, whereupon second element 28 moves in overlying engagement with first element 26 to maintain the latter in sealed relationship relative to gasket 42. Levers 116 are thereupon swung in a clockwise manner as viewed in FIG. 1 until the rollers 128 engage the arcuate portion 54 of annular flange 52 to preclude movement of second element 28 relative to first element 26. It is clear, by virtue of the sealed relationship between annular flange 52 and transverse section 50 of gasket 42, no foreign materials may enter the space between

elements

26 and 28, thus preventing the introduction of contaminating bodies into the tank through the valve means in first element 26.

It is clear that closure member 10 provides a means for easily and quickly gaining access to the interior of the tank to which member 10 is attached and, further permits limited relative movement of

elements

26 and 28. Further, by virtue of the instant structure, first element 26 is not hingedly connected to the tank or device 14 but is hingedly mounted to the second element 28, thus overcoming the objectionable requirement of interrupt ing gasket 42 to clear flange 38 when first element 26 is shifted away from end 12 of device 14. It can be seen that

linkages

98 and 108 are utilized to interconnect

elements

26 and 28 in lieu of hinge means for element 26 operably coupling the latter with device 14 and shell 22. Element 26 is, therefore, prevented from accidentally being dropped from the location on the tank at which it is normally used and thus is prevented from getting contaminated by contact with the ground and surrounding structure. Furthermore, the swinging of element 28 to a position supported by shell 22 is sufficient to partially lift element 26 about from device 14 and thus facilitate the complete swinging of element 26 to a position clearing the open top of device 14.

Linkages

98 and 108 also guide element 26 into element 28 when the former is swung toward the latter and away from device 14. The construction of linkages 98 and is such as to be able to house the latter between

elements

26 and 28 while the peripheral margin of element 28 is utilized to force the entire peripheral margin of element 26 into engagement with head 40 of gasket 42.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. In a manhole assembly for a tank having an access opening therein, a closure member for closing said open ing and including a pair of relatively shiftable elements, a first of said elements having a continuous periphery adapted to be removably disposed in closing relationship to said opening with the periphery thereof engaging the tank in surrounding relationship to said opening a second of said elements adapted to be swingably mounted on said tank for movement toward and away from said opening and said first element when the periphery of the latter engages said tank said second element having a continuous periphery disposed for substantially engaging the entire periphery of said first element to force the latter into engagement with said tank; and means on said elements for inter-connecting the same and for limiting the relative movement thereof, whereby, said first element may be shifted to a location clearing said opening and adjacent said second element when the latter has moved away from said opening to thereby permit access to the latter.

2. In a manhole assembly as set forth in claim 1, wherein said first element is provided with a fiat, outer surface and said second element is provided with a substantially concave inner surface, said means being disposed between said surfaces when said elements are in positions closing said opening.

3. In a manhole assembly as set forth in claim 1, wherein said inter-connecting means comprises a pair of elongated, relatively shiftable components each pivotally secured at one end thereof to a corresponding element and proximal to opposite end thereof to the adjacent component.

4. In a manhole assembly as set forth in claim 3, wherein said components each comprises an elongated U-shaped linkage having yieldable sides and opposed ends pivotally mounted on the corresponding element, and wherein is included pin means on the sides of each of the linkages for pivotally mounting the adjacent linkage thereon for relative movement responsive to the movement of one of the elements relative to the other element.

5. In a manhole assembly for a tank having an access opening therein, a closure member for closing said opening and including a pair of relatively shiftable elements, a first of said elements having a continuous periphery adapted to be removably disposed in closing relationship to the opening with the periphery thereof engaging the tank in surrounding relationship to said opening, a second of said elements adapted to be swingably mounted on said tank for movement toward and away from said opening and said first element when the periphery of the latter engages said tank, said second element having a periphery disposed for substantially engaging the entire periphery of said first element to force the latter into engagement with said tank; clamp means including a swingable roller adapted to be carried by said tank and engageable with said second element for releasably forcing the periphery of the latter in engagement with the periphery of said first element when the latter closes said opening; and means on said elements for inter-connecting the same and for limiting the relative movement thereof, whereby said first element may be shifted to a location clearing said opening and adjacent said second element when the latter has moved away from said opening to permit access to the latter.

6. In a manhole assembly for a tank having an access opening therein disposed in the top thereof, an upright, tubular device adapted to be secured at the lower end thereof to said tank in surrounding relationship to said opening therein; an annular sealing gasket of resilient material carried by said device at the open, upper end thereof; a first element having a continuous periphery and engageable at the periphery thereof with said gasket for sealing the upper end of said device; a second element having a continuous periphery engageable at the periphery thereof with the periphery of said first element in overlying relationship therewith, said second element being provided with an inner surface spaced from the upper face of said first element to provide a hollow space between said elements when the latter overlie the device; hinge means carried by said device and operably coupled with said second element for sw'ingably mounting the latter for movement toward and away from the upper end of the device; and shiftable linkage means on said elements normally disposed within said space for inter-connecting the elements and limiting the relative movement thereof, whereby said elements may be independently shifted to a location clearing said opening to thereby provide access to the latter.

7. In a manhole assembly as set forth in claim 6, wherein said device is provided with a cylindrical side wall, and wherein each of said elements is provided with an annular flange depending therefrom at the periphery thereof adjacent the side wall of said device, the flange of said second element being engageable with said gasket to force the latter into sealing relationship with said device.

8. In a manhole assembly as set forth in claim 7, wherein said gasket is transversely L-shaped and provided with a pair of mutually perpendicular, annular sections, one of said sections projecting outwardly from the side wall of said device and having an upper surface spaced below the upper end of the device, the flange of said second element engaging said surface of said one section in sealing relationship therewith when said second element overlies said first element and said device.

9. In a manhole assembly as set forth in claim 8, wherein said gasket is provided with an annular bead thereon integral with the other of said sections thereof, said head being disposed under compression between said upper end and said first element when the latter closes said end, said one section being disposed to freely flex downwardly under the infiuence of the flange of said second element to thereby permit the full compression of said bead under the influence of said first element.

10. In a manhole assembly as set forth in claim 6, wherein said hinge means comprises a first U-shaped bracket rigidly secured to said device and provided with a pair of spaced legs thereon, a shaft journaled in said legs, and a second U-shaped bracket rigidly secured to said second element and provided with a pair of spaced legs operably coupled with said shaft for rotation relatilvefto said first bracket about the longitudinal axis of said s a t.

11. In a manhole assembly as set forth in claim 10, wherein the legs of said second bracket are provided with recesses therein for receiving the opposed ends of said shaft, and wherein is provided means on said shaft and said second bracket for maintaining the ends of the shaft within said recesses.

12. In a manhole assembly as set forth in claim 6, wherein is included means carried by said device for releasably maintaining the second element in engagement with the first element, said means including an elongated support rigidly secured to said device, an elongated lever swingably mounted on said support for rotation relative thereto about the longitudinal axis thereof, and bearing means carried by said lever and engageable with said second element for urging the latter into engagement with the first element when said lever swings about said axis of said support.

13. In a manhole assembly as set forth in claim 12, wherein said bearing means comprises a roller journaled at opposed ends thereof in said lever.

References Cited in the file of this patent UNITED STATES PATENTS 1,753,946 Replogle Apr. 8, 1930 2,014,861 Neely Sept. 17, 1935