US3164403A

US3164403A - Hatch covers

Info

Publication number: US3164403A
Application number: US259921A
Authority: US
Inventors: Jerome Jack; Jr Robert E Wright
Original assignee: MARINE STEEL CORP
Current assignee: MARINE STEEL CORP
Priority date: 1963-02-20
Filing date: 1963-02-20
Publication date: 1965-01-05
Anticipated expiration: 1982-01-05

Description

Jan. 5, 1965 J. JEROME ETAL 3,164,403

HATCH COVERS Original Filed May 15, 1959 5 Sheets-Sheet l INVENTORS JACK JEROME y ROBERT E. WRIGHT, Jr.

ATTORNEYS Jan. 5, 1965 Original Filed May 15. 1959 J. JEROME ETAL HATCH COVERS 5 Sheets-Sheet 2.

INVENTORS JACK JEROME ROBERT E. WRIGHT, Jr.

' M f M ATTORNEYS Jan; 5, 1965 Original Filed May 15. 1959 J. JEROME ETAL HATCH COVERS 5 Sheets-Sheet 5 Fr q. if

INVENTORA' JACK JEROME ROBERT E. WRIGHT, Jr.

AT ORNEYS Jan. 5, 1965 J. JEROME ETAL HATCH COVERS 5 Sheets-Sheet 4 Original Filed May 15, 1959 INVENTORS JACK JEROME BY ROBERT E. WRIGHT, Jr.

ATSORNEYS Jan. 5, 1965 J. JEROME ETAL 3,164,403

HATCH COVERS Original Filed May 15, 1959 5 Sheets-Sheet 5 INVENTOR. JACK JEROME flw 3 WW ATT RNEYS ROBERT E. WRIGHT, Jr.

United States Patent 3,164,403 HATCH COVERS Jack Jerome, East Williston, and Robert E. Wright, Jr.,

Garden City, N.Y., assiguors to Marine Steel Corporation, New York, N.Y.

Continuation of application Ser. No. 813,522, May 15, 1959. This application Feb. 20, 1963, Ser. No. 259,921

6 Claims. (Cl. 292-2565) This invention relates to hatch covers and more particularly to hatch covers formed of a plurality of motions adapted to be selectively moved either to a position covering a hatch or to a position clear of a hatch and is a continuation of our earlier filed and co-pending application Serial No. 813,522, filed May 15, 1959.

One object of the present invention is to provide an improved hatch cover which can be efliciently and quickly and selectively positioned over and sealed to a hatch or positioned clear of a hatch.

Another object is to provide an improved hatch cover comprising a plurality of sections having novel means for opening and closing said sections whereby said sections are either folded one upon the other at a position removed from the hatch or positioned over a hatch.

Another object is to provide a novel means for supporting the sections of a hatch cover while the same are either being moved clear of the hatch or into a position to cover the hatch.

Another object is to provide a novel means to seal the hatch cover to the hatch.

Another object is to provide a novel means for unsealing a hatch cover.

A still further object is to provide a novel system for controlling the operation of a plurality of hatch covers whereby said covers may be simultaneously moved into a position over the batches and sealed thereto and simul taneously unsealed from the hatches and moved to a position clear of the hatches.

The above and further objects and novel features of the present invention will more fully appear from the following detail description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only, and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a top plan view of a ship showing the deck and three hatches together with hatch covers;

FIG. 2 is a side elevation of a hatch cover, said view being taken on line 22 of FIG. 1;

FIG. 3 is a side elevational view of a hatch cover shown in a partially opened position;

FIG. 4 is aside elevational view of the hatch cover shown in a full opened position;

FIG. 5 is a side elevational view of a'modified version of the hatch cover comprising four sections, shown in full opened position;

FIG. 6 is a fragmentary top plan view of the modified hatch cover shown in FIG. 5 and taken along the confronting edges of the junction of two pair of cover sections, said sections being in their horizontal extended position and covering a hatch;

FIG. 7 is an end elevational view of the hatch cover structure taken along line 7-7 of FIG. 2;

FIG. 8 is an enlarged fragmentary side elevational view of the power actuated hatch cover opening and closing means, said means being shown in the position it occupies when the hatch cover is in its closed position;

FIG. 9 is an enlarged fragmentary side elevational view of the cover guide wheel and seal braking mechanisms shown in FIG. 2;

3,164,403 Patented Jan. 5, 1965 FIG. 10 is an enlarged side elevational view of the cover edge locking mechanisms shown in FIG. 7;

FIG. 11 is a side elevational view of the mechanism for locking the hatch cover sections in open position; and

FIG. 12 is a schematic diagram of the hydraulic system. 7

Referring now to the drawings, there is shown one form of a hatch cover and a system for operating said cover embodying the present invention. It will be understood, however, that the hatch cover structure and system for operating the same may be advantageously and effectively employed in connection with environments other than ship hatches.

In FIG. 1 of the drawings, there is shown a top plan view of a ship having a deck 10 and a series of hatches each having a hatch cover 11. As shown in FIG. 2, there is a coaming 12 surrounding each hatch comprising a vertically extending member 13 and a horizontally extending member 14. The hatch cover 11 comprises two

sections

15 and 16 each being of similar construction and comprising a framework made from longitudinally extending angle irons 17 and transversely extending angle irons 18. To this framework, there is secured by suitable means, such as welding, an outer skin 19 which extends beyond the side edges of the framework and extends over the horizontal portions 14 of the coaming as more clearly shown in FIG. 7. One end of section 15 is secured by a pair of binge members 20 to the horizontal portion 14 of the coaming. A cover section support and seal breaking mechanism 21 is secured to one end of section 16. The cover section hinge and operating mechanism generally designated as 22 is secured to the confronting edges of the cover sections as shown in FIG. 8. Securely fa tened to the under side of the confronting end of sections 15 is a gusset plate 23 which in turn rigidly supports a gear segment 24. A gear segment 25 is rigidly fastened to a piston frame 26 which in turn is secured to the underside of the confronting end of the frame member of section 16. A cylinder member 28 having a piston 29 and a piston rod 30 is pivotally mounted to frame 26.

Ports

31 and 32 are located at each end of the cylinder 28 and are connected by suitable means to a fluid pressure system, to be hereinafter described, whereby the piston and piston rod are horizontally reciprocated by directing a fluid pressure first through one port and then the other. The

gear segments

24 and 25 are so positioned that they engage each other as shown in FIG. 8. A pair of link members 33 are positioned on each side of the

gear segments

24 and 25 and are pivotally secured to gear segment 24 by pin 34 and to gear segment 25 by pin 35. The outer end of the piston rod 30 extends into a cut-away portion 36 on the rear of gear section 25 and is pivotally secured to downwardly depending portions on link members 33 by pin 37. The parts as positioned in FIG. 8 are in the same position as shown in FIG. 2 wherein the

cover sections

15 and 16 are horizontally extended and covering the hatch. When it is desired to open the hatch cover, fiuid pressure is directed into port 32 which in turn moves the piston 29 and piston rod 30 to the left. As the piston rod moves to the left, it exerts, through its pivotal connection to links 33, an upward pressure on said links which in turn move the

gear segments

24, 25 and the integrally formed confronting ends of

sections

15, 16 upwardly. At the full leftward movement of piston 29 the

gear segments

24, 25 and the confronting ends of

sections

15, 16 are in the position shown in FIG. 4. The piston cylinder 28 is pivotally connected at 38 to vthe piston frame 26 and at the other end by the pivotal actuated by cylinder 28 in the manner described above so that all sets of

gears

24, 25 operate simultaneously with each other in moving

sections

15 and 16 to the opened position as shown in FIG. 4.

An upwardly extending steel rib member 39 is secured to the top surface of horizontal portion 14 ofthe coaming and extends around the edge of the hatch. A gasket 40 made of rubber or other resilient material is secured to the lower surface of the framework 17 on each

section

15 and 16 except along the confronting end of each section in such a manner that when the

sections

15 and 16 are secured to the coaming 12 in a manner hereinafter to be described, the rib members 39 will extend into and seal against the gaskets 40. The sealing member between the confornting ends of

sections

15 and 16 is more clearly shown in FIG. 7. Secured to the outer surface of the end frame 18 at the confronting end of section 15 are two gaskets 41 made of rubber or other suitable resilient material which encase a steel rib 42. The gasket members 41 and steel rib 42 are formed in the shape of a broad A. A similarly shaped resilient gasket member 43 is secured to the outer surface of the frame member 18 at the confronting end of section 16 so that when sec tions 15 and 16 are moved to extend horizontally across the hatch, the

gaskets

41 and 43 are in register with each other and the steel rib 42 bites into the gasket 43 to form an airtight and watertight seal between the confronting ends of the two sections. As shown in FIG. 2, the outer skin 19 at the confronting ends of each section do not touch each other when the sections are in a horizontal position covering the hatch so that any sea water which reaches the hatch cover will seep down into this opening, and because of the broad A shape of the sealing member between the two sections, will drain to either side of the hatch.

In order to support the

cover sections

15 and 16 in a position clear of the steel rib members 39 and to aid in the movement of the cover sections during the opening and closing thereof, there is provided a pair of cover section support and seal breaking mechanisms 21 more clearly shown in FIG. 9. These mechanisms are located on each forward corner of cover section 16, as shown in FIGS. 2, 7 and 9, and since both are of identical construction and operation a description of one will be sufiicient for an understanding of all. A frame 48 having a top plate 49, a bottom plate 50 and a pair of side plates 51 are suitably secured together and to the bottom surface of the skin 19 such as by welding. A bell crank 52 is pivotally mounted between plates 51 by a pin 53 and has an integrally formed forward portion 54 and an integrally formed rearwardly extending portion 55. A wheel 56 is rotatably mounted in suitable bearings in the end of portion 54. Each wheel 56 is suitably grooved to ride in a track 57 which is mounted on the top surface of the coaming flange 14 and which longitudinally extends the length of each side of the hatch. A generally vertically extending link 58 has its upper end pivotally secured to the rear portion 55 of crank 52 by a pin 59. A wheel 60 is rotatably mounted in suitable bearings in the other end of link 58 and freely rides on the upper surface of plate 50. A cylinder 61 having a piston and piston rod 62 is pivotally secured at one end to a vertically extending plate 63 on frame 48. One end of piston rod 62 is pivotally secured at 64 to the central portion of link 58.

Ports

65, 66 are located at each end of the cylinder whereby fluid pressure can be introduced to either side of the piston in a manner hereinafter described to reciprocate the same. As the piston rod is moved to the left, as viewed in FIG. 9, the lower end of link 58 will be pivotally moved to the left on wheel 60 which will in turn raise the rear portion 55 of the crank 52 and pivot said crank to simultaneously move the forward portion 54 and wheel 56 downwardly. The

cover sections

15, 16 will thus be elevated above the level of the coaming section 14 and out of the sealed engagement with the rib 39. As will be hereinafter described, the

cover

sections

15, 16 are secured to the coaming 12 to form an airtight seal. Thus, as wheels 56 are moved downwardly, this seal is broken at the two forward corners of section 16 and the wheels will slidably support the cover sections above the coaming and the ribs 39 during the opening thereof through the operation of the mechanisms 21. The link 58 is pivotally moved toward crank 52 until it strikes a stop 67 on the rear surface of the crank. When link 58 is pivotally moved to be positioned against stop 67, the plane extending between the center of pivot point 59 and the center of wheel 60 lies out of a plane extending at right angles to the surface of plate 50. In this manner the weight of

cover sections

15, 16 will prevent wheel 60 from moving to the right, as shown in FIG. 9, and the crank 52 and wheel 56 will support the cover sections above the ribs 39 without the assistance of the fluid pressure in piston 61. An adjustable stop 68 threadedly secured to a horizontal extension of plate 51 engages the forward end of crank portion 55 and provides an adjustment of the downward movement of wheel 56 which in turn controls the vertical movement of

cover sections

15, 16 in relation to ribs 39.

As shown more clearly in FIGS. 7 and 10, there is provided a plurality of edge locking means 69 spaced about the side edges of the

cover sections

15, 16. Since all of the locking means are of identical construction and operation, a description of one will be sutficient for an understanding of all. Mounted to the upper surface of portion 14 of the coaming is a support having a pair of spaced apart rearwardly extending pivot supports 70 and a single upwardly extending bifurcated pivot support 71 positioned between supports 70. A pair of bell cranks 72 having

arms

73 and 74 are pivotally mounted in supports 70 and on each side of support 71. An arm 75 having an adjustable contact pad 76 at one end is pivotally mounted at its other end in the bifurcated support 71. A pair of connecting links 77 are pivotally connected at one end on each side and to the central portion of arm 75 and at the other end to the ends of arms 74 of bell crank 72. The arms 73 of hell crank 72 are pivotally connected to a downwardly extending piston and piston rod 78 which is mounted in a cylinder 79. The lower end of cylinder 79 is pivotally mounted to a suitable support which is secured to the lower surface of coaming portion 14.

Ports

80, 81 are located at either end of cylinder 79 and are connected to a fluid supply system whereby fluid may be selectively directed into first one and then the other to reciprocally move the piston. When the piston and piston rod are moved downwardly the arm 75 and contact pad 76 are pivotally moved through a vertical arcuate path of approximately degrees through bell crank 72 and links 77. A downwardly extending channel member 82 is secured to the lower surface of outer skin 19 and positioned so that contact pad 76 will engage the same when arm 75 is pivotally rotated 180 degrees from the position shown in FIG. 10. The arms 75 and pads 76 will pull the cover sections into contact with the ribs 39 causing an airtight seal to be effected. As will be described hereinafter, all of the cover edge locking mechanisms will be actuated simultaneously so that the peripheral edges of said sections will be simultaneously pulled down and sealed. Because of the arrangement of the pivot point of bell crank 72, the pivot point of arm 75, and the connecting links 77, the pivotal movement of arm 75 can be accomplished only through a force applied to the arm 73 of the bell crank 72. Thus, when arm 75 is pivotally moved so that pad 76 is in contact with member 82, it can only be pivotally moved through an upward force exerted on arm 73 of bell crank 72. In this manner the fluid pressure in cylinder 79 can be cut off entirely after the

cover sections

15, 16 have been scaled and the edge locking means 69 will be locked until the piston and piston rod 78 are actuated.

An open cover locking mechanism 85,- as shown in FIG. 11, is secured to the horizontal coaming section 14 at a position forward of and between the hinge members 20 for the purpose of holding the opened cover sections from accidently closing. The structure of lock mechanism 85 is identical with the structure of the cover edge locking means 69 except for the shape of arm 86 which has a hooked portion at its outer end to engage a flange 87 which is secured to the lower surface of section 16 as shown in FIGS. 3 and 4. Thus, when the

cover sections

15, 16 are positioned as shown in FIG. 4, the fluid pressure is directed to cause the piston rod 78' :to move downwardly which will in turn cause arm 86 to move through a vertical arcuate path until the hooked portion of arm 86 is engaged with flange 87.

In the modified cover structure shown in FIG. 5, a second pair of

cover sections

88, 89 of similar construction as

sections

15, 16 are hingedly connected in tandem to

sections

15, 16 by a plurality of links 90 pivotally connected to the confronting edges of the frames for

sections

16 and 88. Secured to the outer corners of the confronting edges of

sections

16 and 88 and at the forward end of section 88 are cover section support means 91 and 92, respectively, of identical construct-ion, function and operation as cover section support means 21 previously described, to give a slidable support for said sections on the upper surface of coaming portion 14 during opening and closing of the hatch cover. As more clearly shown in FIG. 6, the cover support means 92 are positioned outwardly from its cover frame a greater distance than cover support means 91 so that when the cover sections are extended horizontally end to end and covering the hatch said support means are located adjacent each other. As stated earlier, cover support means 91, 92 function in the same manner as cover support means 21 and all are operated simultaneously so that the airtight seal formed by the cover edge locking mechanism 69 is broken at the corners of the confronting edges of

sections

16 and 88 as well as at the forward corners of section 89. The sealing mechanism between the confronting edges of each of

sections

15, 16, 88 and 89 is identical in construction and operation as the seal between the confronting edges of

sections

15, 16 as shown in FIGS. 3 and 7 and previously described. The cover section operating mechanisms 22 located between

sections

15, 16 and 88, 89 are of the same construction and operation as previously described in relation to

sections

15 and 16. It will be understood that numerous other pairs of section covers may be attached in the same manner as

sections

88, 89 to comprise a cover for larger hatches.

The fluid pressure system is shown schematically in FIG. 12 and comprises a fluid supply tank 95, a motor 96 which simultaneously drives pumps 97 and 98. Pump 97 has its suction side connected to the supply tank and supplies fluid under a pressure of 3000 psi. to a main line 99 which in turn supplies pressure to the cover section opening cylinders 28. Pump 98 also has its suction side connected to the supply tank and supplies fluid under a pressure of 3000 p.s.i. to a main line 100 which in turn supplies pressure to the cover support and seal breaking cylinders 61, the cover edge locking mechanism cylinders 78, and the open cover lock cylinder 78. A conventional four-way valve 101 controls the flow of fluid from line 99 into the cover section opening cylinder 28 so that the line may selectively be completely closed, or the fluid may bypass this cylinder, or the fluid may be directed into either

port

31 or 32 of cylinder 28. A temperature compensated flow control valve 102 of the type made by Vickers, type FCG 024000-20, is positioned in line 99 on the upstream side of the four-way valve 101. Valve 102 is so constructed that the flow away from the four-way valve is precisely controlled to a pre-set gallons-pe-r-minute flow. Additionally, the gallons-per-minute flow is accurately controlled by self-adjustment to compensate for temperature-viscosity-flow characteristics relative to maintaining the preset gallons-per-minute flow.

Cylinders

61, 78 and 78 are operatively connected in parallel with the line 100 and each has a four-

way valve

103, 104 and 105,

respectively, between its cylinder and the line 100. Each of these four-way valves operates in the same manner as four-Way valve 101. As stated above, each cylinder 61 actuates a cover section support and seal breaking mechanism on a hatch cover and all of the cylinders are simultaneously controlled by the four-way valve 103. Similarly, each of the cylinders 78 which actuates the cover edge locking mechanisms 69 are simultaneously controlled by the four-way valve 103. Each of the lines 99 and has a safety valve and return line 106, a by-pass line and valve 107. An emergency connecting line and valve 108 connects

lines

99 and 100 so that the fluid pressure from either of the pumps may circulate in both of the lines should either of the pumps fail to operate. In addition, an emergency pump with suitable check valves connects

lines

99 and 100 in case both pumps should fail. It is to be understood that more than one hatch cover can be controlled from this system by connecting the appropriate actuating cylinders for these additional covers in series with each of the appropriate actuating cylinders so that the particular four-way valve for those cylinders will simultaneously control all of those particular actuating cylinders at :the same time.

The fluid pressure system for the operation of the mod-ified cover section of FIG. 5 is shown in phantom lines on FIG. 12 and comprises a flow control valve 111 of the same type as valve 102, a four-Way -valve 112, and a cylinder 28' of the same construction and operation as cylinder 28. When the cover comprises four sections, as shown in FIG. 5, the cylinder 28 not only has :to lift

sections

15 and 16 into a vertical plane but also has to pull

sections

88 and 89 clear of the hatch. It is also to be understood that additional cylinders 61 to actuate the additional cover support and

seal breaking mechanisms

91 and 92 for each hatch cover are connected in series with the other cylinders 61 so that all are simultaneously controlled by the valve 103.

For purposes of describing the operation of this invention, it is assumed thatthe hatch cover sections are locked in open position clear of the hatch as shown in FIG. 4 and that fluid pressure is being maintained in

lines

99 and 100. First valve is moved to direct fluid pressure into port 81' which in turn moves the locking arm 86 out of engagement with flange 87 and permits the cover sections to be moved into a horizontal plane. Valve 101 is then moved :to direct fluid pressure into port 31 of cylinder 28 which in turn as previously described, causes the

cover sections

15, 16 to be horizontally extended end to end to cover the hatch. When the cover sections are covering the hatch, the valve 103 is moved to direct fluid pressure into port 65 of cylinder 61 so that the wheels 56 are raised, as earlier described, and the cover sections are lowered to come to rest on the rib member 39. The valve 104 is then positioned so that fluid pressure is directed into port 80 of each of the cylinders 79 to move each of contact pads 76 which are spaced about the edge of the hatch into engagement with the channel bar 82 on the cover sections where-by the cover sections are pulled down into sealing contact with the rib 3-9. As described earlier, all the locking mechanisms are so designed that they cannot operate without being actuated as described so that when the cover sections are extended over and sealed to the hatches, they will remain in this condition without the necessity of maintaining a fluid pressure in

lines

99 and 100. When it is desired to open the hatch covers, the reverse of the above procedure is followed. It will also be understood that a plurality of hatch covers can be operatively connected to be simultaneously opened and closed.

Various changes may be made in the means to actuate the mechanisms and in the design and arrangement of the parts of the illustrated embodiment without departing from the spirit and scope of the invention as will now be clear to those skilled in the art. It is therefore to be expressly understood that the present invention is not limited to the particular embodiment thereof herein illustrated and described.

What is claimed is:

1. Apparatus for locking cover sections to a hatch comprising a support adjacent an edge of the hatch, a crank having a first arm and a second arm and being pivotally mounted to said support, a lever having one end pivotally mounted to said support, a link pivotally connected to said second arm and pivotally connected to said lever and actuating means connected to the first arm of said crank whereby said crank is pivotally movable through an angle of substantially 90 degrees while said lever is pivotally movable through an angle of substantially 180 degrees.

2. Apparatus for locking cover sections to a hatch comprising a support adjacent an edge of the hatch, a lever having one end pivotally mounted to said support, a crank having first and second arms, said crank pivotally mounted intermediate said arms to said support at a point below and laterally displaced from the pivotal mounting of said lever, means operatively connecting the second arm of said crank to said lever, crank actuating means operatively connected to the first arm of said crank whereby said crank is pivotally moved through a predetermined angular path and said lever is pivotally moved through an angular path which is twice that of said crank.

3. Apparatus for locking cover sections to a hatch comprising a support adjacent an edge of the hatch, a lever pivotally mounted at one end to said support and movable through an angle of 180 degrees, a bell crank having first and second arms and being pivotally secured to said support at a point horizontally and vertically displaced from the pivotal mounting of said lever, a link pivotally mounted at one end to the second arm of said crank and pivotally mounted at its other end to said lever, actuating means operatively connected to the first arm of said crank whereby said crank arms are oscillatably movable through an angle of 90 degrees.

4. Apparatus for locking cover sections to a hatch comprising support means adjacent an edge of the hatch, a lever pivotally mounted at one end to said support, a bell crank having first and second arms and being pivotally secured to said support at a point horizontally and vertically disposed from the pivotal mounting of said lever, a link pivotally mounted at each end to the second arm of said crank and to said lever, actuating means operatively connected to the first arm of said crank whereby said crank is oscillatably moved through an arcuate path and said lever is movable through an arcuate path twice that of said crank.

5. Apparatus for locking cover sections to a hatch comprising support means adjacent an edge of the hatch, a first lever pivotally mounted at one end to said support, a shaft transversely disposed in said support at a point horizontally and vertically disposed from the pivotal mounting of said lever, a second arm secured at one end to said shaft, a link pivotally mounted at each end to said first and second levers whereby said levers are positioned parallel and spaced apart from each other, actuating means secured to said shaft for imparting oscillating rotation to said shaft whereby said levers are moved through arcuate paths and whereby said first lever moves through an arcuate path twice as great as said second lever.

6. Apparatus for locking cover sections to a hatch comprising a plurality of supports spaced along an edge of said hatch, a shaft transversely extending through and rotatably supported in said supports, a plurality of first levers, each of said first levers being pivotally mounted at one end to one support at a point vertically and horizontally disposed from said rotatably mounted shaft, a plurality of second levers, each of said second levers being secured at one end to said shaft at a point adjacent one of said supports, a plurality of link members, each of said link members being pivotally secured at each end to said first and second levers on each support, means to impart oscillatory rotational movement to said shaft whereby said first and second levers are pivotally moved through an arcuate path.

References Cited in the file of this patent UNITED STATES PATENTS 2,857,874 McBride Oct. 28, 1958 2,949,091 Lovell Aug. 16, 1960 2,981,326 MacGregor Apr. 25, 1961

Claims

1. APPARATUS FOR LOCKING COVER SECTIONS TO A HATCH COMPRISING A SUPPORT ADJACENT AN EDGE OF THE HATCH, A CRANK HAVING A FIRST ARM AND A SECOND ARM AND BEING PIVOTALLY MOUNTED TO SAID SUPPORT, A LEVER HAVING ONE END PIVOTALLY MUNTED TO SAID SUPPORT, A LINK PIVOTALLY CONNECTED TO SAID SECOND ARM AND PIVOTALLY CONNECTED TO SAID LEVER AND ACTUATING MEANS CONNECTED TO THE FIRST ARM OF SAID CRANK WHEREBY SAID CRANK IS PIVOTALLY MOVABLE THROUGH AN ANGLE OF SUBSTANTIALLY 90 DEGREES WHILE SAID LEVER IS PIVOTALLY MOVABLE THROUGH AN ANGLE OF SUBSTANTIALLY 180 DEGREES.