US1905427A - Lifting device - Google Patents

Description

LIFTING DEVICE Filed Ot. 14, 1931 4 Sheets-Sheet 1 IN VENTOR.

Adolo/v J. Ao/(erm 00 B Y H/Ls ATTORNEYS A ril 25, 1933. A. .1 ACKERMA LIFTING DEVICE Filed Oct. 14, 1931 r 4 Sheets-Sheet 2 hll? ATTORNEYS Aprifi 25, A. ACKERMAN LIFTING DEVICE Filed Oct. 14, i931 4 Sheets-Sheet 3 INVENTOR. Ado4o/7 J. Ac/(erm'on BY amut/(Z ms ATTORNEYS April 25, 1933. A. J. ACKERMAN LIFTING DEVICE Filed Oct. 14, 1931 4 Sheets-Sheet 4 IN VENTOR. Ado/pl; J. Ackerman HIS A TTORNE Y5 Patented Apr. 25, i933 PATENT OEFICE anonrn J. acxnamm, or manxa'ro, mmnaso'ra nmrme :nnvrcs A Application filed October 14, 1981.

This invention relates to lifting devices for use with hoists or cranes and more particularly to devices that will automatically take hold of the load and automatically release the same when it has been placed in a desired position.

Specifically stated the apparatus embodying the invention, and to be hereinafter described in detail, relates to lifting devices for use with gantry cranes or the like, whereby gates such as are embodied in dams, may be automatically engaged by the act of lowering the device to a suitable or predetermined position, then raised or lowered to a predetermined or desired position, and thereafter automatically disengaged from the device, and the various operations initiated and controlled from a point more or less remote, as from the crane or hoist.

Since the apparatus embodying the invention is, for purposes of illustration, shown in connection with flood gates of dams, a general reference may be made to prior art apparatus and devices which have been used for raising and lowering gates of this type.

In the handling of excess water and large flood discharges over a dam, it has been customary heretofore to provide gates and suitable hoisting means for raising these gates, in order to provide openings through which such excess water or discharges may spill.

v In many cases, sliding gates have been used.

To raise and lower the gates as required, trav eling hoists have been utilized which could be spotted over a selected gate, and after manually making the necessary connections between the gate and the hoisting cables, the gates were raised or lowered to some predetermined or desired position.

In the past the above mentioned lifting and lowering operations have been obtained by rather cumbersome machinery and equipment that require the services of from two to four men in making the necessary connections to the gates.

An object of this invention is the provision of a lifting device which may be utilized in connection with present types of traveling hoists or cranes whereby it may be possible for one operator, stationed in a. cab or other Serial No. 568,787.

suitable position, to perform the raising and lowering operations of the ates while sta tioned in the cab, without t e aid of other workers or operators.

Another object of the invention is the provision of lifting apparatus of the character referred to above, whereby a single operator may raise or lower a series of gates, while stationed in the cab of a traveling crane or hoist, in a much shorter riod of time than so has heretofore been possi le with other forms of lifting devices.

A still further object of the invention is the provision of a lifting device, that may be utilized with existing traveling cranes or 5 hoists, designed to automatically engage or disengage a gate, by the act of merely raising or lowering the flexible cables from which the device is suspended.

Other objects of the invention will, in art, be apparent and will, in part, be obvious rom the following description taken in conjunction with the accompanying drawings in which:

Figure 1 is a view in elevation partly in section of a dam having a gantry crane provided with a lifting device, embodying the invention, for raising and lowering a gate or gates of the dam;

Fig. 2 is a view in front elevation of the 30 structure shown in Fig. 1;

Fig. 3 is a fragmentary top plan view partly in section, taken on line IIIIII of Fig. 4, of a lifting device embodying the invention, said. device being dis osed in the gate slots over a gate to be lifte Fig. 4 is a view in front elevation, partly in section, of the arrangement shown in Fig.

3 taken on line IVIV thereof;

Fig. 5 is a partial view in vertical section of a pier disposed between two adjacent gates, said pier being provided with dogs upon which the gates may rest;

Figs. 6 to 10, inclusive, are partial views, partly in section, of a lifting hook and latch embodied in the lifting device illustrating the several operative positions of the hook and latch, with reference to a gate to be lifted, as the lifting device is successively actuated to and from gate engaging position;

Fig. 11 is an end view of the hook, latch and a portion of the gate, taken in the direction of arrows XI-XI of Fig. 8;

' characters indicate like parts.

In Figs. 1 and 2 of the drawings a dam 1 is shown on the crest of which spaced piers 2 are formed. The piers are spaced a predetermined distance apart to provide a spillway 3 through which excess water may flow over the dam. The spillway is provided with a gate 4 which is arranged for vertical movement in guideways 5 formed in the sides of the piers. By raising and lowering the gates, the amount of water spilled over the dam may be re ulated in accordance with head water conditions.

It is apparent from Figs. 1 and 2 that only a. portion of the dam is shown. However, it is to be understood that. a dam, such as illustrated, may include a large number of spillways and gates, depending upon the width of the dam.

Since the invention herein illustrated is applicable to dams having a large number of gates which must at certain times be raised and lowered as quickly as possible, without requiring the services of more than one operator, a lifting device 6 is provided that may be suspended at each end from flexible cables 7 that are raised and lowered by means of suitable hoisting drums (not shown) located in a gantry crane 8.

The gantry crane 8 is arranged to travel.

' back and forth on rails 9 laid on a platform or support 10 constructed above the top of the dam.

The gantry crane may be provided with the usual electric motors and suitable control equipment (not shown) whereby the crane may traverse the dam from one side to the other and be spotted over any particular gate, and whereby the hoisting cables may be raised or lowered as desired. The equipment for controlling the traversing movements of the gantry crane and the raising and lowering of the hoist cables may be.

operated by one operator stationed in the crane cab 11.

Lifting device 6 is so arranged that by the act of raising or lowering the hoist cables, it may be caused to take hold of any particular gate selected. raise it to a predetermined position, in which it is held by support means to be hereinafter described in detail, and then disengaged from the gate so that the gantry crane may be shifted to another position and spotted over another gate to be raised or lowered.

Lifting device 6, which is shown more in de- 7 tail in Figs. 3 and 4 of the drawings comprises a beam 12 having a pair of sheaves 13 at each end thereof, whereby the beam may be raised or lowered by means of the cables shown in Figs. 1 and 2, and hooks 14, one at w inwardly beveled faces for engaging the sides of a channel 17 formed in each gate slot 5 of the respective piers 2, or if the top of the gate is extending above the side channels 17, the inside faces of the rollers will travel over similarly shaped guide channels 17' permanently attached to the side members of each gate, and thus guide the beam to the correct position with respect to the lifting eyes 18.

Since one pair of rollers 16 is disposed at the top edge of the beam and another pair at the bottom, the beam is so guided as it is lowered to position that it will enter the gate slots properly without-turning about its 1ongitudinal axis.

In order that hooks 14 may engage and take hold of a gate to be raised or lowered an eye or socket 18 is formed, as shown in Fig. 4, in upwardly extending plates 19 secured to the top of the gate structure at the ends thereof. When the beam is being lowered into position to take hold of a gate, means are provided for swinging the hooks in such manner that they will register with the eyes or sockets 18 formed in the lifting plates. As illustrated the means for so swinging the hooks, comprises sloping cam surfaces 20 formed at the lower ends of the hooks at the outer sides thereof.

As the lifting device is being lowered to position over a gate, the hooks 14 hang vertically as shown in Figs. 4 and 6. However, when the lifting device is in such position that the cam surfaces of the hooks engage the top edges of the plates in which the eyes or sockets 18 are formed, the hooks swing inwardly (see Fig. 7 until the curved ledges 21 thereof register with the eyes or sockets 18, as shown in Fig. 8. When in such registering position, the hooks are in vertical position again, and the gate may be raised or lowered, as the case demands.

When a gate hasbeen lifted or raised a predetermined amount, it is brought to rest on pivotally mounted dogs or supports 22 carried by the piers. The dogs 22 swing auto- 40 from the 5 rality of blocks 23 are provided. These blocks are attached to the gate structure at the end sidesthereof and are spaced vertically at predetermined points according to requirements. As shown in Fig. 5, one of the blocks is disposed near to the top of the gate and immediately below the plates in which an eye or socket 18 is formed, and another block is attached to the gate near to itsbottom edge, one block being shown in connection with a gate to the left of the pier 2 and the other block being shown in connection with a gate disposed to the right of the pier.

After the gate has been raised or lowered to the proper position and brought to rest on dog 22, means are brought into action by the act of lowering the lifting device 6, for disengaging the hooks from the gate sockets or eyes 18, and holding the hooks in such position until the lifting device has been raised to a point where the hooks will swing free of or clear them.

The means for disengaging the hooks from the eyes or sockets 18 comprises a cam 24 formed on the outer side of each hook at a point above the projection 21 of the hook that engages the eves or sockets. To disengage the hooks from the gate the lifting device is lowered until cams 24 strike the top edges of the plates in which the eyes or sockets are formed.

As the lifting device is lowered, cams 24, as

they slide over the top edge of plates 19, cause the hooks to swing outwardly and away from the plates until the hooks are disengaged from the sockets. When the hooks are disengaged sockets or eyes, a latching means comes into action that holds or looks thehooks n their disengagement position. The latchmg means is so constructed that it will hold the hooks in their disengaged position until the lifting device has been raised sufiiciently to prevent the'hooks reentering theeyes or soc ets.

When the hooks are clear of the eyes or sockets in the gate the latch mechanism is tripped, releasing t e hooks to their normal vertical position as indicated in Figs. 4 and 6. The position of the latching mechanism is indicatql in Fig. 4 and the form, construction and operation thereof is depicted in Figs. 6

to 12, inclusive.

The latching mechanism comprises a latch member 25'which is pivotally mounted on a pin 26 secured td beam 12 adjacent the lower portion of the hooks 14 (see Fig. 11) and to one side thereof. As shown one portion of the latch member is adapted to engage a flange 27 secured to the top of the plates 19 to one side of the adjacent eye or socket 18. The other end of the latch member is offset 55 as shown in Figsr 11 and 12 and is provided with a downwardly extending catch or stop 28 which is adapted to cooperate with a pin 29 secured to the lower portion of hook 14. The latch member 25 is normally held in a horizontal position as shown in Figs. 6, 7 8 and 9, by means of'a weight 30 that depends from the latch member at a point in line with the pin 26 on which the latch member is mounted.

The operation of the hooks 14 and the latch members 25 may be best understood by reference to Figs. 6 to 10, inclusive. When lifting device 6 is lowered to that position in which the hooks 14 take hold of the gate either 'to lift it or lower it, the cam surfaces 20 on the hooks strikes the up er edge of the plates in which the eyes or soc ets are formed and swing the hooks to a position such as indicated in Fig. 7. It will be understood that the hook shown in Fig. 7 corresponds to the hook shown at the right hand end of beam 12 as viewed from Fig. 4. It will also be appreciated that the hook at the other end of the beam swings inthe opposite direction to that indicated in Fig. 7. As the lifting swing into the sockets or eyes 18 of the gate as shown in Fig. 8. When the hooks are in this position the gates may be lifted or lowered as the case-may be. After the gates have been placed in a desired position it is brought to rest at the opposite end sides on dogs 22 cooperating with the blocks 23 attached to the end sides of the gate. The hooks may be disengaged by lowering the device is lowered still further, the hooks lifting device further until the hooks occupy the position shown in Fig. 9.

As the beam 12 is beinglowered, hooks 14 are swung to the position shown in Fig. 9 by cam surfaces 24 that ride on the upper edges of the plates directly above the eyes or sockets '18. When the hooks occupy the position shown in Fig. 9, the pin attached to the lower portion of the hook abuts against the catch or lug 28 forming part of the latch member 25 as shown in Fig. 10. The hooks when in the position shown in Fig. 10 will now clear the eyes or sockets 18 in the gate when the lifting device is raised still higher. As' the device is raised. latch member 25 engages the flange 27 attached to the upper portion of the plates 19. As the lifting device is raised still higher, the latch member is turned more and more in'the direction indicated in Fig.

- 10 until the catch or lug 28 is tripped free of the pin 29. When the pin on the hook has been tripped free of the latch member, the hook is high enough to clear the socket or eye in the gate, so that the lifting device includtion the lifting device may be lowered to take a new hold of the gate, or as stated above, the lifting device may be lifted out of the gate slot and spotted over some other gate.

' In some cases it may be desirable to employ a double hook construction at each end of the lifting beam instead of a single hook such as shown in Figs. 6 to 12, inclusive. A double hook construction is shown in Fig. 13. \Vhere a double hook arrangement is employed, the hooks are disposed to swing away from each other when the lifting device is lowered to a'position to take hold of the gate, and towards each other after the hooks have been disengaged from the gate.

If a double hook construction is employed, each end of the gate is provided with an upright 32 having oppositely extending shoulders 33 to be engaged by the hooks when the gate is to be lifted. Each upright is also provided at its upper end with cam surfaces 34 and 35 arranged in the form of a triangle, the surfaces converging at the top and running from the top to the outer edges of the shoulders 33 as shown.

The double hook construction comprises oppositely swinging hooks 36 which are mounted on pins 37 at their upper ends, the pins being supported in the ends of the 11fting beam 12. Each hook is provided with a double face or triangular shaped cam 38 disposed between the hook jaws 39 and the hinge pins. The double faced cams operate to swing the hooks clear of the shoulders 33 on the gate when it is desired to ralse the lifting device out of the gate slots after agate has been adjusted to the proper position. The hooks are held in position to clear the shoulders 33 on the gate by means of latches 40 of the type shown in Figs. 6 to 12, inclusive. These latches cooperate with pins 41 secured to the lower ends of the hooks as in the construction shown in Figs. 6 to 12, inclusive.

In operation, the double hooks, as they approach the shoulders 33 of the upri hts secured to the gate, strike the cam sur aces 34 and 35 and are separated until the hook jaws slip under the shoulders. When in this position, the gates will be raised or lowered by appropriately operating the lifting mechanism. To disengage the hooks from the gates, the beam of the lifting device is lowered until the double cams 38 slide over the cam surfaces 34 and 35. When the hooks have swung to a predetermined position, the pins 41 on the hooks engage the stop or catch 42 on the latch member and are held in a position corresponding to that depicted in Figs. 9 and 10. As the lifting device is raised still higher, the adjacent ends ofthe latch members 40 engage a pin 43 formed at the apex of the triangle formed by the cam surfaces 34 and 35 and shoulders 33. This pin turns the latch members one in a clockwise and the other in by a link 46 to an arm 47 formed on the top I of each lifting hook. Thus when the hooks swing inwardly towards the middle of the, beam, the indicator balls swing in the direction indicated by arrows 48 and 49. When the hooks are hanging vertically, indicator balls and the levers 45 will occupy a vertical position. Such position of indicator balls may therefore indicate that the beam has not been lowered far enough to engage or take hold of the beam or that the hooks are in engagement therewith, as shown in Fig. 4. 4

Indicating mechanisms, such as described, may, obviously be applied to the double hook construction shown in Fig. 13.

The dogs 22 which are utilized for holding the gates in any predetermined position, normally hang in such a position that as the gate is being raised the dogs are swung inwardly into the piers (see Fig. 5) by the blocks 23 attached to the end sides of the gate, and then returned automatically to the position indicated in full lines in said Fig. 5. IVhen a block 23 on the gate has moved upwardly past one of these dogs and-the gate is subsequently lowered, it comes to rest on the dogs as shown in Fig. 5.

If-a gate has been raised to a predetermined moved inwardly into the pier to permit the blocks on the ends of the gates to clear them on its downward travel. In order to provide for swinging the dogs out of the path of travel of the blocks 23, a push rod 50 is provided with each group of dogs. As shown, the push rod is rovided with lugs 51 and 52 located above 0g arms 53 so that by pushing the push rods downwardly, the dogs will be swung to such a position that the gate supporting tips 54 thereof will be disposed within the pier, as indicated in broken lines in Fig. 5. The upper end of each push rod is provided with a weight 55 arranged to turn the dogs to the position shown in broken lines.

Each group of dogs may be actuated either 7 of the turned accordingly either raising or lowering the push rod to one or the other of the positions indicated in Fig. 5. Each cam and shaft 56 is turned by means of an arm 60 having a pin 61 thereon for engaging the cam to turn t e same, the arm being loosely mounted on the shaft. The outer end of the arm is provided with a weight 62 sufiicient to turn the cam in the direction required.

The dog operating mechanisms shown in Fig. 5 are identical except that the operation mechanism operating the dogs at the left hand side of the pier is the reverse of the operation of the mechanism associated with the dogs at the right side of the pier.

As shown, the weight arm 60 of the dog operating mechanisms extend in the same direction. When in these positions, one group of the dogs at the right of the pier is in position to support a gate, and the group of dogs at the left of the pier is in position to permit the gate to travel downwardly to the crest of the dam. If the weight arm 60 controlling the dogs at the left of the pier is swung 180, the pin 61 thereon will engage the cam causing it to turn counterclockwise thereby raising the push rod 50, permitting the dogs to swing to the position corresponding to the position occupied by the dogs at the right side of the pier. When in this position, the gates may be su ported in any desired elevation. If the ga e at the right of the pier is to be lowered to the crest of the dam, weight arm 61 associated with the dogs for this gate, is turned 180 whereby the do s will swing out of the path of travel %locks 23 on the gate. As soon as the lifting device 12 has been attached to the gate and slightly raised to remove the load from tips 54 of the dogs. It is obvious that the operator may turn the weight arm at any time before he chooses to lower the gate or gates.

The weight arms 61 utilized for controlling the position of the supporting dogs 22 also serve as a means for indicatin whether the dogs are in the full line or in t e broken line positions illustrated in Fig. 5.

The form and construction of beam 12 may vary considerably with requirements although for most cases it is preferred to construct the beam as shown in Figs. 3 and 4. As shown the beam is made up of side plates 64 of the general shape of the beam as viewed from Fig. 4, and top and bottom plates 65 and 66 appropriately secured together and braced by means of angles as shown. The plates and angles may be secured together by welding. Each end of the beam is open from top to bottom and this opening is divided into three compartments 67, 68, and 69, the outer compartments housing the sheaves 13. The sheaves, as shown, are journalled on stub shafts 70 secured in the side lates and extend through the beam from t e front to the -or rivets.

The construction of the piers as such form 7 no particular part of this invention exce t that they are designed with compartments 4 in which the gate supporting dogs 22 may be mounted. These compartments are large enough to afford ample room for the dogs and the operating mechanism therefor.

parent that a lifting device is provided. which may be utilized with existing equipment such as traveling cranes or hoists and which ma be caused to automatically take hold 'of a load by the act of lowerin the device into position, and which may e automatically disengaged from the load by the act of lowerlng the device below its load engaging p sition and then raising it until the latching mechanism has tripped the load engaging parts of the device to their normal position, so that the device may again be lowered to take hold of the load.

While the device has been shown in connection with dams and as being applicable for raising and lowering gates which con trol the spillage of water over the dam, it will be apparent to those skilled in this art that the lifting device has many other appllcations where it is necessary to raise and lower an object at difl'erent times and where it is convenient to afiect engagement and disengagement between the load and the device automatically while at a remote point.

It will be readily apparent and appreciated by those skilled in the art that various modifications and changes may be made in the apparatus herein disclosed without departing from the spirit or the scope of the invention. It is desired therefore that only such limitations shall be placed on the invent-ion as are imposed by the prior art and the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A lifting device comprising a beam supported at its opposite ends from a flexible support adapted to raise or lower the beam, means at each end of the beam adapted to automatically take hold of the load by the act of lowering the beam to load engaging position, and means on the load coacting with said automatic means arranged to automatithe operator is stationed I .85 From the above description it will be apfree cally disengage the same from the load by' the act of lowering said beam to a point below the load engaging position.

2. A lifting device comprising a beam supported at the opposite ends from a flexible support adapted to raise or lower the beam, means on the beam adapted to automatically take hold of the load by the act of lowering the beam to load engaging position, means for coacting with said automatic means arranged-to automatically disengage the same from the load by the act of lowering said beam to a point below the load engaging position, means for locking said automatic means in disengaged position until said beam has been moved away from the load, and means for automatically releasing said automatic means to load engaging position when the beam has moved away from the load.

3. A lifting device comprising a beam supported at its opposite ends from a flexible support, hooks pivotally supported from the ends of said beam, said hooks being normally free to swing and operable to load engaging position by the act of lowering the beam to loading position and then raising the same, means on said hooks adapted to coact with the load to swing the hooks to unloading position by the act of lowering the beam below loading position, latch means for holding the hooks in unloading position as the beam is raised, and means on the load coacting with said latch means for automatically releasing the hooks to free swinging position in res onse to the beam being moved to a point a ve said load engaging position.

4. A lifting device comprising a beam supported at its opposite ends from a flexible support, hooks pivotally supported from the ends of said beam, said hooks bein normally free to swing and operable to loa engaging position by the act of lowering the beam to loading position and then raising the same means on said hooks adapted to coact with the load to swing the hooks to unloading position b the act of lowering the beam below said oading position, latch means for holding the hooks in unloading position as the beam is raised, means on the load coacting with said latch means for automatically releasing the hooks to free swinging position in response to the beam being moved to a oint above said loading position, and inicatin means connected to said hooks for indicating the position thereof as the beam is raised or lowered with respect to the load.

5. The combination with a movable gate having a member thereon disposed for .en-

agement by a lifting device to raise or lower t e same, 0 a beam adapted to be suspended from hoist cables or the like, a hook pivotally supported on said beam and being normally free to swing, a cam on said hook adapted to swin it into engagement with said gate mem r as the beam is lowered to lifting position, a cam on.the hook coacting with the gate for swinging the hook to gate disengaging position in response to movement of the beam below its gate lifting position, a latch on the beam adapted to lock the hook in disengaged position, and means on the gate for releasing the latch and unlocking the hook in response to upward movement of the beam past gate lifting position.

6. The combination with a movable gate having a member thereon disposed for engagement by a lifting device to raise or lower the same, of a beam adapted to be suspended from hoist cables or the like, a hook pivotally supported on said beam and being normally free to swing, a cam on said hook adapted to swing it into lifting engagement with said gate member as the beam is lowered to lifting position, means coacting with the gate and hook for swinging the hook to gate disengaging position in response to movement of the beam below its gate lifting position, means on said beam arranged to hold said hook in unloading position while the beam is being raised to a point above gate engaging or lifting position, and means on the gate to automatically release the hook to free swinging position when the hook is out of gate engagin position.

7. The com ination with gate piers having guideways therein, and a gate mounted in said guideways adapted to be raised and lowered therein, said gate having a socket in the top thereof, of a lifting device adapted for suspension from a hoist cable or the like, and means on said device adapted to coact with the gate so as to automatically actuate said means into and out of the gate socket by the act of lowering and raising said lifting device, said means, when actuated into said socket, bein in position to suspend the gate from the li ting device so that the gate may be raised or lowered thereby, and means in said guideways adapted to coact with the lifting device and maintain it in operative alinement with respect to the gate as said device is raised or lowered.

8. The combination with a gate adapted to be raised or lowered, said ate having a socket therein, of a lifting device adapted for suspension from a hoist cable or the like, a hook pendulously suspended from said device adapted to be received in said gate for automatically actuating the hook into lowering and raising said lifting device, there being means for supporting the gate in predetermined or selected positions to which it may be raised or lowered.

10. The combination with gate piers havg guideways therein, and a gate mounted in said guideways adapted to be raised and lowered therein, said gate having a socket in the top thereof, of a lifting device adapted for suspension from a hoist cable or the like, means on said device adapted to coact with the gate to actuate said means automatically into and out of the gate socket by the act of lowering and raising said lifting device, said means when actuated into said socket being in position to suspend the gate from the lifting device so that the gate may be raised or lowered thereby, and gate supporting mem-' bers in said piers adapted to automatically engage the gate to hold the same in a selected position to which it may be raised.

11. The combination with a gate having a member at each end'at the top thereof disposed for engagement by a lifting device adapted to raise or lower the same, of a beam adapted to be suspended from hoist cables or the like, a hook at each end of the beam pivotally supported thereby and being normally free to swing, a cam on said hooks adapted to actuate them into lifting engagement with said members as the beam is lowered to lifting position, means 'coacting with the gate and hooks for swinging the hooks to gate disengaging position in response to movement of the beam below its gate lifting position, means on said beam arranged to hold said hooks inunloading position while the beam is being raised to a point above gate engaging or liftingposition, and means on the gate adapted to automatically release the hooks to free swinging position when the hooks are out of gate engaging position.

12. The combination with gate piers having guideways therein and a gate mounted in the guideways adapted to be raised or lowered therein, said gate having a member thereon adapted to be engaged by a lifting device to raise or lower the same, of a beam adapted to be suspended from hoist cables or the like, a hook pivotally supported on said beam and being normally free to swing, a cam on said hook adapted to swing it into lifting engagement with said gate member as the beam is lowered to liftin position, means coacting with the ate and hook for swinging the hook to gate 'sengaging position in response to movement of the beam below its gate lifting position, means on said beam arranged to hold said hook in unloading position while the beam is being raised to a point above gate engaging or lifting position, means on the gate to automatically release the hook to free swinging position when the hook is out of gate engaging position, and means in said guideways for guiding the beam so as to maintain the hook in operative alinement with the member on said gate.

13. A gate lifting device adapted for use with gantry cranes and designed to automatically take hold of a gate, disposed in guideways, to raise or lower the same and to automatically release the gate after having been adjusted to a predetermined position, said device comprising a beam adapted to span the gate and to operate in the gate guideways, a hook mounted at each end of the gate and being normally free to swing, a cam on each hook adapted to engage the gate as the beam is lowered so as to swing the hooks into engagement with book receiving members on the gate when the beam has been lowered to gate lifting position, a latch at each end of the gate, said latches being provided with means urging them at all times towards latching position, a cam on each hook adapted to engage the gate and swing the hooks to gate disengaging position in response to lowering of the beam below gate lifting position and into engagement matically take hold of the gate as the beam is lowered to gate lifting position, means on the hooks adapted to coact with the gate to swing the hooks to gate disengaging position in response to the lowering of the beam below gate lifting position, and latches on the beam,

one for each hook, adapted to lock the hooks in gate disengaging position while the beam is being raised, said latches being disposed to engage the gate and be tripped thereby to release the hooks to normal position as the beam is raised above gate lifting position.

In testimony whereof, I have hereunto subscribed my name this tenth day of October,

ADQLPH J. ACKERMAN.

lifting device adapted for use i

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