US2550882A

US2550882A - Hoist safety valve

Info

Publication number: US2550882A
Application number: US735700A
Authority: US
Inventors: Frederick W Sturm; Ross H Arnold
Original assignee: Wayne Pump Co
Current assignee: Wayne Pump Co
Priority date: 1947-03-19
Filing date: 1947-03-19
Publication date: 1951-05-01
Anticipated expiration: 1968-05-01

Description

May 1, 1951 F. w. STURM ETAL HOIST SAFETY VALVE Filed March 19' 1947 2 Sheets-Sheet l n@. @@w z May 1, 1951 E. w. STURM ETAL HOIST SAFETY VALVE Filed March 19, 1947 NVENTO 2 Sheets-Sheet 2 II/l/l/I/IIIIIIIIIIIIII Iw\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ I Patented May 1, 1951 TENT OFFICE HOIST SAFETY VALVE Frederick W. Sturm and Ross H Arnold, Fort Wayne, Ind, assignors to The Wayne Pump Company, Fort Wayne, Ind., a corporation Maryland ApplicationMaroh 19, 1947, Serial No. 735,700

9 Claims.

This invention pertains to lifts or hoists and the construction thereof including lift safety valves for full hydraulic and semi-hydraulic hoists, the valves insuring that a proper amount of fluid will be kept in parts of the hoist-system for proper and safe operation of the hoists.

It is an object of this invention to provide a lift utilizing any desired form of superstructure wherein in the operating mechanism there are few parts to wear, and such wearing parts are disposed so that maintenance operations can be easily and simply performed.

Another object of the invention is to provide a lift which is simple to installa'nd maintain and wherein safety means is provided to insure that the proper amount of operating fluid is maintained in the lift system for proper and safe operation.

Another object of the invention is to provide safety-mechanism for lifts which is operative und er v predetermined conditions to prevent operation of the lift to raised position, butwillipermi t the lift to be lowered should trouble occur such as that due to'leakingpacking or pipeline.

Another object of the invention is to provide a lift wherein safety mechanism is provided which will permit the lift being renderedinoperative should a failure occur when the-lift is in lowered position, and will permit the-lift to be lowered by normal operation if trouble occurs wh'en the lift is in raised position.

Another objectof the invention is to provide safety mechanism forlifts which are applicable to lifts of either the full hydraulic-or semi-hydraulic types. 1

Another object of the in'vention'is toprovide safety control mechanism for lifts operative uponfpredetermined failure to render the lifting mechanism of the lifts ineffective but which can be readily moved to inoperative position after the failure hasbe'en corrected.

Another object of 'the'dnvention is to provide lift structure utilizing a fixed casing and a, relatively'movable ram, which may be rotated with respectto the casing, and wherein widely spaced I bearings are provided for-theram.

Another object of the inventionis to' provide a lift construction wherein a relatively fixed casing and movable ram is provided and wherein fixed and movable bearings areprovided fo'r the ram.

With these and various'other objects in view, the invention consists of certain novel features of construction and operationas will .bem'ore fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings, which illustrate an embodiment of the device and whereinlike referencecharactersare used to designatelikepwts:

Figure 1 is a sectional elevation through a semi-hydraulic hoist operating cylinder and piston embodying the invention, and showing a safety valve applied thereto;

Figure 2 is an enlarged, fragmentary sectional elevation through a portion of the piston head showing the application thereto of the safety valve shown in Figure 1;

Figure 3 is a sectional elevation of a full hydraulic hoist showing the operating tank for the piston, the operating tank being provided with the hoist safety valve; and

Figure 4 is an enlarged fragmentary sectional elevation of the hoist safety valve illustrated. in Figure 3.

Referrin first of all more particularly to the structure illustrated in Figure 1, the outer fixed cylinder or casing I0 is embedded in the ground l2 preferably so that a portion of the upper open end of the casing Ill will project slightly above the ground level. The inside of the casing for at least a portion of its length from the lower endis machined to form a bearing surface i l, the,

length of the bearing surface depending upon the lift, and the lower end of the casing I0 is closed by means of the head or lower closure [6. The head is provided with the recess or passage l8 communicating with the air supply pipe 20 which extends upwardly and is connected through the manual control valve 22 to the pipe 24, which in turn is connected to a suitable source of air pressure. While air is referred to as the pressure supplying fluid, of course, it is understood that any other suitable operating fluid may be used.

The hollow, movable ram, piston or plunger 26 is mounted in the casing l0 and is provided with the lower closure 28, so disposed within the ram 26 that the lower end of the plunger forms a flange or skirt 3!], said flange being apertured as at 3| and provided with the lower bearing 32 having sliding engagement with the bearing surface I4 of the casing It. The upper end of the casing [0 is closed by means of the upper guide bearing 34 which has bearing engagement with the.

ram 26 and is provided with the flange 35 overlying the flange 38 provided on the casing Ill, whereby the

flanges

36 and 36 may be connected together. The bearing 34 is provided with the packing recess 40 adapted to receive suitable with the upstanding standpipe 52 communicating with the passage I6 and is so disposed that its axis coincides with the axes of the casing I4 and ram 26. The standpipe 52 extends through the closure 28, the opening in the closure 28 through which pipe 52 extends being sufiicient to provide an oil passage '54, and other oil passages 56 are provided in the'closure 28, the flow through the passages 56 being controlled by the valve disk 58 carried by the stem 60 fixed to closure 28;

An air eliminator, indicated generally at 62, communicates with the inside of the ram 26 through fitting 64 and pipe 56, said pipe extending to and being conveniently anchored in the stop ring 08, which is spaced from the lower bearing'32 a predetermined distance, and is adapted to contact the upper bearing 34 to limit the distance the ram may be raised.

The upper end of the standpipe 52 is secured as at I to the spring seat fitting 12 which in turn is connected as at I4 to the valve body housing' 16. Housing l2 is provided with the spring seat I8 upon which the lower end of the poppet lifting spring 80is disposed, the upper end being adapted to engage the guiding finsBZ of the poppet 84. The poppet is urged upwardly by means of the spring 80, and under conditions to be later described, is adapted to close the valve seat 86 provided on the housing l6. Thepoppet 84 is provided with the upwardly extending stem 88 which extends through a suitable guide 90 provided on the bracket 92 which extends within the downwardly directed flared flange 94 of the cap 96, when the ram is in lowermost position.

Cap 96 is secured as at 08 to the top closure I00 secured to the upper end of the plunger, the closure I00 being adapted to be connected by suitable cross bracing (not shown) to suitable: rails, such as the drive-on or free wheel type where the hoist is used for automotive vehicles;

and connected to any other type of support where; Types of hoist superstructure and the connections thereof to the ram are shown and described in applica the hoist is adapted for other uses.

tion Serial'No; 604,407, filed July 11, 1945 for Hoist. plug I02 whichniay be removed for permitting access to stem.83 for manually depressing said:

stem.

Stern 83 is provided with the latch collar I04 which is adapted to have cooperative engagement with the latch member I06 of the latch H33.

Latch I06'is pivoted as at IIO to the bracket 92 and is provided with thele'g 'II2 adapted to be loosely engaged between nuts H4 and H6 provided on the float rod II8 to secure said leg to said rod. The float rod extends downwardly:

a predetermined distance through a passage H9 (which may be a bearing) and is provided with the float I slidably and loosely mounted around the standpipe 52, the position of the float being determined by the oil level in the ram 26.

taining the oil level in an automobile engine crank case. The line I24indicates the oil level within ram 26 when it is in its lowermost position." The gauge may also be marked with other marks I showing Full and Low levels and of course other marks may be applied as desired. While foil has been referred to as being the fluid in the casing and ram other suitable fluids of course can be used.

In the operation. of the device, let it be as- The cap 96 is provided with'an opening sumed that the oil level within the ram 26 is at its normal operating height, and the ram is in lowermost position (Figure 1). In that position the flange 30 acts as a lower stop by engaging the closure I6. With the oil level at its .normal height, the float I20 will be urged upwardly so that the latch I06 will be urged in 'a clockwise direction as viewed in Figure 2. The collar I04, when the stem 86 is depressed, is engaged by the latch member I06 retaining the poppet 84 in open position. When it is desired to raise the ram, valve. 22His properly operated, admitting operating fluid, such as compressed air, through pipe 20, passage I8, standpipe 52 and through housing I6 to the space between the top of the oil in ram 26 and the closure I00. The oil will be forced downwardly through

passages

54 and 56 to raise the plunger a predetermined amount such as until stop 68 engages bearing 34 or at some intermediate point as when the valve 22 is closed before the stop reaches the upper bearing. Release of .the air pressure within the'ram by operationof valve 22 will permit the oil between the casing and ram to flow through passage 54 into the ram to displace the air through housing 76 to permit the lowering of the ram.

After use, if the oil level should drop to a position where the float I20 is permitted to move downwardly too far, the downward movement of the float I20 will move the latch member I06 out of engagement with the collar I04 and the spring 80 will close the poppet 84. Should this occur while the ram is in raised or partially raised condition, it can still be lowered as the air pressure within ram 26, acting on the upper surface of valve'84, will overcome the force of spring 80 to open poppet valve 84 when valve 22 is positioned so as to release air pressure from within the ram. Oil can be supplied to the ram by removing the gauge I22 and using the opening as a fill opening, and when the oil is at its proper level, the gauge can be replaced closing the fill opening, the plug I02 (which may also be used as an oilfill opening) can be removed, and the stem 88 can be depressed to permit the poppet 84 to be locked open by engagement of the latch member I06 with the collar I04. The lift is then ready for normal raising and lowering operation.

Referring now to the full hydraulic type of lift or hoist illustrated in Figure 3, said lift comprises the outer fixed cylinder or casing I26 which is adapted to be fixed within the ground I28 with its upper end slightly above the ground, the casing being provided with the lower closure I30, the casing I26 being provided for at least a portion of its length with the bearing surface I32 for the lower bearing I34 provided on the depending flange or skirt I36 of the ram, piston or plunger I38. The lower end of the ram or plunger is closed by means of thelower closure member I40 whereby the flange or skirt I36 is defined, said skirt preferably being provided with the passages I42, and the ram being provided with the stop ring I44 disposed a predetermined distance above the lower bearing I34 and being adapted, in the uppermost position of the ram, to engage the undersurface of the upper bearing I46 disposed in the upper portion of the casing I26. In the lowermost position of the ram the skirt I36 acts as a lower stop by engaging the closure I30.

The bearing I46 is provided with the outwardly extending flange I48 overlying, and being adapted to be connected to, the flange I50 provided at the upper end of the casing I26. Upper bearing I46 is adapted to have bearing engagement with the ram and is ip'rovided with the packing recess ISI for the reception of suitable packing, such as the chevron .packing I52. The packing is retained by the upper closure plate I54 secured to the flanges I48 and I50, and a wiper may be provided in recess I56 or this may be a lubricant recess or groove. A wiper I58 and upper retaining member I60 is provided, retaining member I60 being adapted to be connected to the flange I48. The upper end of the ram I38 is provided with the :closure I62 which is connected through suitable bracing (not shown) to the superstructure desired, "as described above. In this construction it .is noted that the operating fluid, such as oil, isretained only between the casing I26 and the ram I38. -Operating tank I64 containing fluid preferablythe same as in the casing, (such as the oil) v=is-conveniently disposed with respect to the hoist and is provided with the pipe I66 extending froma 'point adjacent the bottom of the tank I64 upwardly, and being connected through the manual oil control valve I68 to the pipe I10, which:"is='connected through oil control valve I12 to "the casing I26, flow to and from the casing being permitted through the opening I14. The operating fluid is disposed within the casing I26 and in pipes I and I66 and in the operating tank 164 to a predetermined level, the level of the 'st-appro'ximatelysafe oil level being indicated as atI-18.

"A -removable calibrated gauge I80 is provided on the upper end of the tank operative in the same mann'er as gauge I22 to ascertain the oil level. ;It is desirable that the oil level be retained at a point higher than the line I16, being preferablyretained at'the high mark indicated by the line I82. The upper head I84 of the tank I64, through '-Whi0h pipe I 66 extends, is provided with thevalvfebody I86 threaded or otherwise secured as at I88-to the head-I84, the top of the body I86 being closed, :by'means of the threaded plug I90. The-gbody l86is provided withthe valve seat I92 adapted to be controlled by the valve poppet I94, thepoppet I94 'beingprovided withthe depending float rod, :I96 extending downwardly through bushing-l98 disposed above the skirt 200 of the body 186, an air passage between the valve and tank beingprovided at 202.

v The skirt-200 is provided with the depending float rod tube 204'provided with the vent holes 206 and within which is disposed the float 208 secured to the float rod I96'adjacent the lower end thereof. The upper end of the housing I86 above the poppet I94 is I provided with the air inlet "210 adapted to be secured to a suitable source of fluid pressure, as air pressure, the supply, of-yairto and from theinlet 202 being controlled by "a suitable manually controlled air valve (not shown). Within the housing I86 there is provided alatch'pivot2I2to which the latch member 2I4 is pivoted, the latch and pivot being so constructed and arranged that the free end of the latch tends to move counterclockwise in Figure' l) into the path of the poppet I94, saidlatch having a reset lug 2I6.

,When the oil level is sufiiciently high, the float 208 is urged upwardly, urging the poppet I94 upwardly away from its seat'I92. The plug I90 can be; removed and the latch '2I4 moved to its dotted'line position as illustrated in Figure 4,

byflepressing lug 216, thus permitting the poppet *I 94 -to" raise :to a point where-it is open and diS-e 6 posedfin thepath of the latch, retaining the latch in its dotted line position. Operating air "can then be supplied through the opening 2I0, passing downwardly past the valve seat I92 to the space between the oil and head 184 of the tank I64 through passages 202, forcing'the oil'through pipe I66, valve I68, assuming said valve to be open, through pipe I10 past valve I12 into the casing I26, causing raising mov'ementof the rain I 38. 1'

Opposite operation of the air control valve will, of course, permit air pressure abovethe oil in the tank [641:0 be released permitting down-- ward movement of the ram I38. Shouldthe oil level fall below a predetermined level, such as 118, the float '208, will move downwardly, moving the poppet I94 toward seat closing position, pe'rmitting the latch 2I4 to move to its latched position as shown in the full line position illustrated in Figure 4. In this full line position, the poppet I94 is closely adjacent its seat so that any'air pressure'supplied through the opening 210, will seat the poppet I94, preventing the pressure from reaching the oil in the operating tank I64. As'before, downward movement of the ram would be-permitted should the oil level fall, and should the ram be in a raised or partly raised position, as the air pressure above the oil in tank I64 would be permitted :to bleed past the valve I94, due to the fact that the latch 2I4 is of such length as to permit a slight movement of the poppet I94 from seated position.

It is to be understood that this application is not to be limited by the exact embodiments of the device shown, which are merely by 'way of illustration and are not limited thereto, as various and other forms of the device will, of course, be apparent to those skilled in the art without departing from the spirit of the invention'or the scope of the'claims.

We claim:

l. Hoist construction comprising 'ascylinder, a ram mounted to reciprocate vertically within said cylinder, the upper portion of saidram being-adapted to be provided with load supporting superstructure, said cylinder being adapted .to contain a liquid, means for introducing fluid pressure above the level of the liquidin said cylinder, and means for preventing introduction 'of said fluid pressure into said cylinder when the level of the liquid is below 'aprede termin'ed point the second named means including' 'a 'normallyopen valve for -controlling fluid flow to raise or lower the ram, means for causing the valve to" close should thefluid level fall below the predetermined le'velfand means for holding said valve in closed position after it is once closed, said last named means being ineffective to'close thevalvewhen the fluid level is above the predetermined level and the valve is open.

2. Hoist construction comprising 'a cylinder, "a

ram mounted to reciprocate 1 vertically Within said cylinder,theupper portion ofsaid ram being adapted to be provided with load""'supporting superstructure, said cylinder and said ram being adapted'tocontain a'liquid, means for introducing fluid pressure above-the'level'of the liquid in said ram, and means for preventing introduction'o'f said fluid'pressure into said'ram when the level of theliquid isbelow a predetermined point, said last'n'a'med'meansbeing movable to permit authorized escape of said fluid "pressure on said liquid when saidram is in araise'd position.

=3.-I-Ioist' construction comprising' a cylinder, 'a

ram mounted to reciprocate vertically within said cylinder, the upper portion of said. ram being adapted vtobe provided with load supporting superstructure, said cylinder being adapted to contain a liquid, "an operating tank connected to said cylinder andhaving liquid therein, means for introducing fluidpressure above the level of the liquid in said operating tank, and means for preventing introduction of said fluid pressure into said tank when the level of the liquid in the operating tank 'is below a predetermined point, said last named means being movable to permit authorized escape of said fluid pressure on said liquid when said ram is in a raised position.

i 4'. Hoist construction comprising a cylinder, a ram mounted to reciprocate vertically within said cylinder, the upper portion of said ram being adapted to be provided with load supporting superstructure, said cylinder and said ram being a adapted to contain a liquid, means for introducing fluid pressure above the level of the liquid insaid ram and permitting release thereof, and means, for preventing the introduction of said fluid pressure into said ram when the level of the liquid is below a predetermined point in said ram.

5. Hoist construction comprising a cylinder, a ram mounted to reciprocate vertically within said cylinder, the upper portion of said ram being adapted .to be provided with load supporting superstructure, said cylinder and said ram being adapted to contain a'liquid, means for introducing, fluid pressure above the level of the liquid in said ram and permitting release thereof, and means'ior preventing the introduction of said fluid pressure into said ramiwhen the level of theliquid is below. a predetermined point in said ram, but permitting said fluid pressure to escape from the interior of said ram through said first named means when said ram is in a raised position.

-6. Hoist construction comprising a cylinder, a rammounted .to reciprocate vertically within said cylinder, the upper portion of said ram being adapted to be provided with load supporting superstructure,.said cylinder and said ram being adapted to contain a liquid, means forintroducing fluid pressure above the level of the liquid in said ram, and means for preventing introduction of said fluid pressure into said ram when the 4 level of the liquid is below a predetermined point.

7., In a hoist, the combination of an outer fixed casing, an inner slidable ram disposed to slide in said casing and having an upper end adapted to be provided with a load supporting superstructure, a closure for the lower end of said casing, a closure for the upper and lower ends of said ram, liquid disposed in said casing and ram, the ram lower closure being provided with an opening permitting communication between said casing and ram, means for supplying fluid pressure into said ram above the liquid level therein for raising said ram and exhausting fluid pressure to lower said ram, said means having a valve for controlling supply and exhaust of fluid pressureto and from said ram and provided with a latch member, a latch adapted to engage the latch member to hold the valve in open position to permit entrance of fluid pressure to said ram, a float in said ram connected to said latch in such a manner that when the liquid level is above a predetermined point the valve may be latched open, but when it falls to a point at or below said predetermined point the float unlatches the valve, and a resilient member for closing thewalve when the latch is in .unlatched position and the liquid levelis at or below saidipredetermined. points 8, In a hoist, the combination of an outer fixed casing, an inner slidable ram disposed to slide in saidcasing and havingan upper end adapted to .be. provided with a load supportingisuper structure, a .closure ,for the lower end of said casing, a closure vfor lower end of said ram for preventing fluid access to said ram, liquid dis- -posed insaid casing around said ram, a liquid container connected to said casing and having liquid therein, means for supplying fluid pressure to said container above the level of liquid therein to thereby force the liquid from said container to said casing to raise said ram, said last named means including a housing having an opening to said container having a valve controlling said opening, said housing having a fluid pressure connection whereby said fluid pressure is supplied to or exhausted from said valve,.a float in said container connected to said valve urging it to open or closed position as governed by the liquid level in said container, and a biased latch in said casing which prevents opening movement of said-valve after the liquid level has fallena predetermined amount until the level has been raised to a predetermined point and the latch moved to inoperative position where it is main tained by said valveuntil the liquid level falls a predetermined distance.

9.., In a hoist, the combination of'an outer fixed casing, an inner slidable ram disposed to slide in said casing and having an upper end adapted to. be provided with a load supporting superstructure, liquid disposed between said casing and ram, valve means through which operating fluid regulates the amount of liquid disposed between said casing and ram for selectively raising, or lowering said ram, means for rendering said valve means ineffective'if the level of said fluid falls below a predeterminedlevel, the second named mean including a housing adapted tobe con-' nected to a source of operating fluid, said h0us-' ing having a valve seat and normally open valve for seating on said seat, said valve in open posi-' tion permitting flow of operating fluid to raise or lower the'ram', said valve in closed position preventing flow of operating fluid to raise the rain, means for causing the valve toclose should the liquid level fall below the predetermined level, said last named means including a member positively movable from one extreme position where the valve is closed to another extreme position where the valve is open, the last named means being ineffective to close the valve while the fluid level is above the predetermined level and the valve is open.

FREDERICK W. STURM. ROSS H. ARNOLD.

REFERENCES CITED The following references are or record in the file of this patent:

v UNITED STATES PATENTS