US2138886A - Soaking pit cover crane - Google Patents

Description

Dec. 6, 1938. c. H. SCHRAMM SOAKING PIT COVER CRANE Filed Nov. 2. 1936 4 sh s sh et 1 ZkUe/zzbr' I" CH 50572227271 Dec. 6, 1938. SQHRAMM I 2,138,886

SOAKING PIT COVER CRANE Filed Nov. 2, 1936 4 Sheets-Sheet 2 3W 1 I v F OIO Jtfarzzea/s 1933- c. H. SCHRAMM 2,138,886

SOAKING PIT COVER CRANE Filed Nov. 2, 1956 4 Sheets-Sheet 3 jZkUe/zawf C: H jc/zramm Dec. 6, 1938. c. H. SCHRAMM 2,138,886

SOAKING PIT COVER CRANE Filed Nov. 2, 1936 4 Sheets-Sheet 4 fizz/e72 for.

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Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE SOAKIN G PIT COVER CRANE Application November 2, 1936, Serial No. 108,801

16 Claims.

This invention relates to improvements in traveling cranes and more particularly to cranes for use in raising, lowering and traversing the heavy fire brick covers of high temperature furnaces or soaking pits of the floor installed type.

Soaking pit installations usually embody in one structure a plurality of heating pits or furnaces arranged in side-by-side relation in one or more rows. To obtain maximum operating emcienoy, it is highly desirable that the pits be arranged as close together as possible to form a compact group. The compact arrangement, in addition to saving valuable space, simplifies the pit structure and permits the use of smaller and less expensive charging machinery for placing ingots in and removing them from the pits. The pits are closed by individual fire-brick lined covers and it has been the usual practice heretofore to provide a separate cover handling mechanism for each pit. This mechanism is arranged to raise and lower the cover as required and to carry it to one side of the pit to open the same. With this construction, the pits must be spaced sufficiently far apart to provide room for the steelwork supporting structure of the mechanism and to leave a space available adjacent each pit for receiving the cover when the pit is opened.

With the foregoing in view, the primary object of the invention is to .provide an improved soaking pit cover crane adapted to serve a plurality of soaking pits thereby materially reducing the initial cost of cover handling mechanism in multiple pit installations and reducing the amount of space required for such mechanism to enable the pits to be arranged in more compact and eflicient groups than has heretofore been practicable.

Another object is to provide an improved traveling crane for multiple soaking pit installations embodying remotely controllable means of an advantageous character whereby the crane may be placed in operative relation with the various pits selectively and detachably connected with the pit covers for raising, lowering and traversing the same.

Still another object is to provide improved cover gripping means for soaking'pit cranes selectively operable from a remote point to grip or release a pit cover and embodying means for effectually preventing the release of a cover while in raised position.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiments illus trated in the accompanying drawings, in which:

Figure 1 is a perspective view of a soaking pit cover crane embodying the features of the invention.

Fig. 2 is a fragmentary plan view of the crane showing the control platform Fig. 3 is a plan view of the trolley.

Fig. 4 is an elevational view of the crane trolley with the supporting bridge structure shown in section.

' Fig. 5 is a front view of a cover gripping mechanism.

Fig. 6 is a side view of the cover gripping mechanism showing the manner in which the gripping jaws' are opened and closed to grip or release a pit cover.

Fig. '7 is a side view of the cover gripping mechanism showing the positions of the various parts where the pit cover is elevated.

Fig. 8 is a detail view of the gripper operating mechanism as provided for the crane shown in Figs. 1, 2 and 3.

Fig. 9 is a plan view of a modified form 01' the soaking pit cover crane.

Fig. 10 is an elevational view of the crane shown in Fig. 9.

Fig. 11 is a detail view of the gripper operating mechanism for cranes of the type shown in Figs. 9 and 10.

Referring now to Fig. 1, ll indicates the top of the masonry structure forming a group of soaking pits and constitutes the floor of the furnace or pit room. The pits are arranged in parallel longitudinal and transverse rows, one transverse row comprising a pit in each longitudinal row being shown by way of illustration as indicated by the reference characters l2, l2 and. I2. The pits may be arranged in any convenient number of rows, however, and there may be any desired number of pits in each row.

The pits l2, l2 and I2 are provided with individual covers I3, l3 and I 3 respectively which are adapted to rest on the upper part of the masonry structure and seal the pit openings. The covers may be of any suitable construction and ordinarily comprise a metal shell lined with fire brick capable of withstanding the extreme heat at which the pits are operated. Each cover has suitable members, as for example, the T-rails l4, welded or otherwise secured to the metal shell for convenience in operatively attaching the cover handling mechanism thereto.

As shown in Fig. 1, rails ii are mounted on suitable supports such as I-beams l6 extending along opposite sides of the longitudinal rows of pits and parallel thereto. The rails form a track for a traveling crane including a movable frame or bridge i'l spanning the pit structure. As herein shown, the bridge I! comprises a pair of heavy box girders I3 connected by transverse beams l9 at each end. The transverse beams carry flanged wheels or rollers 23 running on the rails i5 whereby the bridge may be moved along the rows of pits and alined with the various transverse rows as required.

One of the wheels 23 at each end of the bridge is arranged to be driven by means including a shaft 2| (Figs. 3 and 4) iournaled on the transverse beams l3 and extending the length of the bridge. A gear train 22 (Fig. 4) or the like communicates power from the shaft to the wheels 20. The shaft 2| is driven by a motor 23 (Fig.

- 2) through the medium of a shaft 24 and a speed reducer 23 (Fig. 4) mounted on supports carried intermediate the ends of the bridge between the girders I3. A magnetic brake 23 of any desired construction provides a means for quickly stopping the motor to interrupt the travel of the bridge. A limit switch 21 mounted on the bridge and adapted to engage stationary switch operating members 28 is connected in the circuit of the motor 23. One switch operating member is provided for each transverse row of pits, the member being so positioned that the bridge is automatically stopped in proper alinement with the row of pits.

Rails 29 mounted on the girders l3 comprise a track for a load carriage or trolley 33 which carries the cover gripping and elevating mechanism to be described presently. As will be seen by reference to Fig. 1, the trolley comprises a rectangular metal frame 3| having a pair of flanged wheels or rollers 32 at each end engaging the rails 29 whereby the trolley may be moved trans versely of the rows of pits to aline it with any one of the rows. Thus, by a combination of bridge and trolley movements, the trolley may be spotted over any desired pit in the group.

For transversing the trolley 33 on the bridge, one wheel 32 of each pair is arranged to be driven by a reversible electric motor 33, (Fig. 3) through the medium of a speed reducer 34, shaft 35 and s able driving connections such as a chain and sprocket drive 33 connecting the shaft to the respective wheels. ates to stop the motor 33 and quickly arrest the travel of the trolley. A limit switch 21' of any preferred construction mounted on the trolley and arranged to cooperate with switch operating members 23 mounted on the bridge in alinement with the several rows of pits is connected in circult with the trolley traversing motor 33 for facilitating accurate positioning or spotting of the trolley relative to the pits.

The trolley 33 carries suitable elevating means for raising and lowering the pit covers so that the covers may be moved laterally of the pits by traversing the trolley and bridge. The elevating means is arranged to be operatively connected with any desired one of the pit covers and, to facilitate such connections, is provided with novel cover gripping means adapted to be controlled from a remote point.

Referring more particularly to Figs. 4, 5, 6 and 7, the elevating means includes two vertically disposed lifting arms 33, one at each end of the trolley, spaced apart so that the arms lie directly over the gripping members H of a cover when the trolley is spotted over the same. As shown in Fig. 5, each arm 33 comprises a pair of steel bars 33 connected at their lower ends by a pin 43 on which are pivotally mounted a pair of opposedly faced, hook-shaped tongs or A magnetic brake 31 oper- I jaws 4| adapted to cooperate with the gripping member M of the cover to detachably connects pit cover to the arms.

The upper ends of the respective arms 33 are connected by pivot pins 43*to. rockers or bell cranks 42 and 43 comprising, in the present instance, a pair of generally triangular steel plates pivotally supported on the trolley frame 3| by stub shafts 44 and 43 respectively. The rockers are connected to move together by means of a reach rod 43. For swinging the rockers to raise or lower the arms 33, a crank arm 41 is keyed or otherwise secured to the shaft 44 which carries the rocker 42. The crank arm 41, in turn, is connected by a pitman 4'3 with a crank shaft 43 iournaled on the frame 3|, the arrangement being such that rotation of the crank shaft is eflective to oscillate the crank arm 41 and rockers 42 and 43 between upper and lower limit positions. Power for driving the crank shaft is obtained from an electric motor 33 through a speed reducer 3| and gear train 32. A rotary limit switch of any preferred construction may be connected with the crank shaft 43 and adjusted to interrupt the circuit of the motor 33 at the extreme points of crank throw so that the elevating mechanismflm will be stopped automatically at the proper Rotation of the rockers 42 and S3 in a counterclockwise direction is effective to raise the lifting arms 33 vertically and thus lift the pit cover sufficiently to clear the covers of adjacent pits when the cover is moved laterally to open the pit. Suitable guide means is provided to prevent lateral swinging movement of the lifting arms during the cover raising and traversing operations. To this end, each of the lifting bars 33 is connected'intermediate its ends with a link 33 pivotally mounted on the frame of the trolley. Where space is available, the links are connected directly to the bars 33, otherwise, connection is made with a bracket 34 carried by the bar as shown in Figs. 3 and 4. I

To facilitate the connection of the elevating mechanism with thepit covers, remotely controllable means is provided for moving the gripper jaws 4| into or out of gripping relation with the cover members I4. Referring more particularly to Figs. 6 and 7, each of the jaws 4| is formed with an outwardly projecting arm 33 operatively connected with an actuating rod 33. As herein shown, the operative connection is provided by links 31 mounted on a common pivot pin 33 carried on the end of the actuating rod and connecting respectively to the arms 33. Movement of the rod 53 to its upper position swings the jaws outwardly to the position shown in dotted line in Fig. 6 while downward movement closes the jaws together as shown in full line in the figure referred to. Guide means including a pair of spaced guide bars 39 mounted on the pins 43 and 43 between the lifting bars 33 and having vertically disposed slots 33 adapted to slidably receive the ends of the pivot pin 33 insure equal movements of the links 31 and jaws 4|.

The jaws 4|, when in closed position. are adapted to engage the T-rail gripping member H of the cover when the elevating mechanism operates to raise the lifting arms 33. To avoid any possibility of the jaws slipping and to prevent opening of the same when a cover is in raised position, each jaw is formed with an inwardly projecting lug 3| adapted to interlock with a suitable recess 32 formed in the underside of an auxiliary head 33 secured to the head of the T-rail H. The weight or the cover-is thus effective to prevent opening of the jaws so that release of the cover is possible only when it has been lowered to its resting position on the floor.

Movement of the actuating rod 66 to open and close the jaws 4| is effected bymeans including a weighted bell crank 64 to which the upper end of the rod is connected. A separate bell crank is provided for each set of laws and, as herein shown, the bell cranks are loosely mounted on the stud shafts 44 and 45 between the plates forming the rockers 42 and 43. Each bell crank is provided with a counterweight 85 positioned so as to normally raise the actuating rod to its upper position and thus hold the jaws 4| open. Suitable means is provided for rocking the bell cranks 54 against the action of their weights to close both sets of jaws simultaneously. In the preferred form of the invention, this means includes a solenoid 66 mounted on the trolley frame 3| and opratively connected with the respective bell cranks 64. operative connection is provided by rigid steel rods 61 and 88 extending from the respective bell cranks to one arm of a bell crank lever 89 pivotally mounted on the frame 3| below the solenoid. The other arm of the lever 69 has a pin and slot connection with a rod Ill connecting with the armature of the solenoid. Thus, when the solenoid is energized, the lever 69 is rocked in a counterclockwise direction as viewed in Fig. 8 and corresponding movements are imparted to the bell cranks 64 through the medium of the rods 61 and 6B. Deenergization of the solenoid permits the bell cranks to return to normal position and open the jaws 4|.

Current for energizing the gripper operating solenoid 65, the trolley traversing motor 33 and elevating motor 50 is supplied over conductors II mounted on the inner side of the girder l8 for engagement by sliding shoes 12 carried on the trolley. Starting and stopping of the mechanisms is effected by controlling the energization of the conductors The controllers utilized for this purpose may be of any suitable type and are preferably centralized at a convenient point or control station such as a control platform 13 (Fig. 2) carried at oneend'of the bridge I'I. As

shown in Fig. 2, four manually operable controllers 14 are provided, one of which controls the operation of the bridge traversing motor 23. The other controllers are in circuit with the con.- ductors 1| for controlling the motors 33 and 50 and the solenoid 66 of the trolley. Thus, the operations of the crane to raise, remove, return and lower the pit cover maybe conveniently and safely controlled by means of conventional switching devices without exposing the attendant to danger.

In the modified form of the crane shown in Figs. 9 and 10, the parts corresponding in construction and function to those hereinbefore described are identified by the same reference characters. The crane includes a movable bridge I5 adapted to span a plurality of rows of soakingpits and, like the bridge l1, previously described, is supported by flanged wheels 20 running on the track formed by rails i5 extending parallel to the rows of pits. The motor23 drives the bridge in either direction through the medium of the speed reducer 25 and shaft 2|; In this instance, however; the driving connection between the shaft 2| and the wheels 20 is in the form of a As shown in Figs. 3 and 8, the- 3 will be appreciated that any suitable driving con,- nection may be employed. v

The modified form oi the crane also differs from the. embodiment hereinbefore described in that the trolley is dispensed with and a separate set of elevating and gripping means is provided for each row of pits. The rockers 42 of each set of elevating mechanisms are mounted on a common shaft 'l'l arranged to be driven by the motor 50 in the same manner as the stub shaft 44. The gripping jaws 4| and the mechanism for opening and closing them is also similar to that previously described. In' this case, however, manually operable control means is utilizedfor actuating the jaw operating mechanism.

Referring particularly to Fig. 11, it will be observed that the weighted'bell cranks 64 for rais- A similar lever 84 and suitable connections including a cable 85 is provided for each additional set of gripping and elevating mechanism. Thus, by actuating the levers, the gripping jaws may be closed selectively to render any desired set of mechanisms operative. It will be understood, of course, that the rockers 42-43 of each set are operated together. However, only the set whose gripping jaws have been closed will be effective to lift a cover.

It will be apparent from the foregoing that the invention provides an improved soaking pit cover crane particularly suitable for multiple pit installations. The crane embodies meansof an advantageous character whereby it may be "quickly and easily placed in operative relation with any pit in the group and detachably connected with the pit cover for raising, lowering and traversing the same. Opening and closing the pits is facilitated by reason of the simple and efflcient control means whereby the various operating functions of the crane including the gripping and releasing of the pit covers is controllable from a porting structure requires a minimum of floor space thereby permitting a compact and eiiicient arrangement of the pit structure.

I claim as my invention:

1. The combination with a group of floor installed soaking pits arranged in parallel rows, each of said pits having an individual cover, of rails located-on opposite sides of the group of pits forming a track parallel to said rows, a bridge mounted on said track and spanning the rows of pits, a trolley on said bridge movable longitudinally thereof whereby the trolley may be positioned over any pit in the group by combined movements of the bridge and trolley, cover raising and lowering means on said trolley, cover gripping means efiective when operated to operatively connect said raising and lowering means with the cover of the pit over which the trolley is positioned, and means operable from a remote point for operating said gripping means.

2. The combination with a group of floor installed soaking pits arranged in parallel rows, each of said pits having an individual cover, of

chain and sprocket connection 16 although it rails located on opposite sides of the group of 7 pits forming a track parallel to said rows, abridge mounted on said track and spanning the 'rows of pits. a trolley on said bridge movable longitudinally thereof whereby the trolley may be positioned over any pit in the group by combined bridge, means for operatively connecting said raising and lowering mechanism with the covers of the respective pits, and means for selectively operating said connecting means.

4. The combination with a group of soaking pitsof the floor installed type having individual covers, of a cover handling crane including a bridge spanning the pits, a cover raising and lowering mechanism for each pit mounted on said bridge,

.said mechanisms being normally disconnected from the pit covers, power driven means for simultaneously operating said mechanisms, and selectively operable means for operatively connecting said mechanisms with their associated pit covers one at a time.

5. A traveling crane for raising, lowering and traversing the individual covers of a group of floor installed soaking pits comprising, in'combination, a movable bridge spanning the group of pits, a trolley movably supported on said bridge, said trolley being positionable over any desired pit in the group by combined movements of the bridge and trolley, a pair of bell crank levers pivoted on the trolley, lifting arms depending from said levers arranged to be operatively connected with the cover of the pit over which the trolley is positioned, and motor means for simultaneously swinging said levers to raise and lower the pit cover.

6. A traveling crane for raising, lowering and traversing the individual covers of a group of floor installed soaking pits comprising, in combination, a movable bridge spanning the group of pits, a trolley movably supported on said bridge, said trolley being positionable over any desired pit in the group by combined movements of the bridge and trolley, liftingarms depending from said levers, a set of normally open jaws mountedtaneously to raise and lower the cover gripped by said jaws.

7. A traveling crane for raising, lowering and traversing the individual covers of a group of floor installed soaking pits comprising, in combination, a movable bridge spanning the group of pits, a trolleymovably supported on said bridge, said trolley being positionable over any desired pit in the group by combined movements of the bridge and trolley, lifting arms depending from said levers, a set of normally open jaws mounted on each of said arms, said jaws being effective when closed to grip the cover of the pit over which the trolley is positioned, a solenoid mounted on the trolley operative when energized to close said sets of jaws, motor means for swinging said bell crank levers simultaneously to raise and lower the cover gripped by the jaws, and

' centralized control means mounted on said bridge for controlling the energization of said solenoid and the operation of saidmotor means.

8. In a soaking pit cover crane having a frame adapted to span a soaking pit, in combination, a pair of lifting arms depending from the frame, motor means on the frame for raising and lowering said arms, gripping means carried by each of said arms for cooperating with gripping members arm with the cover, saidgripping means comprising a pair of pivotally mounted hook shaped jaws, means normally operating to hold said jaws in open position, and manually controlled means for closing the jaws of both gripping means simultaneously.

10. 'In a soaking pit cover crane having a frame adapted to span a soaking pit, in combination, a pair of lifting arms depending from the frame, motor means on the frame for raising and lowering said arms, gripping means car-' ried by each of said arms for cooperating with gripping members on the pit cover to operatively connect the arm with the cover, said gripping means comprising a pair of pivotally mounted hook shaped jaws, a bell crank lever pivotally mounted on the frame, a jaw actuating rod connecting said lever and said jaws whereby the jaws may be opened and closed by swinging said lever, a counterweight for said lever operative to hold the jaws in open position, and means for swinging said lever against the action of said counterweight to close the jaws.

11. In a soaking pit cover crane having a frame adapted to span a soaking pit, in combination, a pair of lifting arms depending from the, frame, motor means on the frame for raising and lowering said arms, gripping means carried by each arm for cooperating with gripping members on the pit cover to operatively connect the arm with the cover whereby the cover may be raised or lowered by said motor means, said gripping means comprising a pair of jaws operative when closed to grip said member, and interlocking means on the jaws and member operative to preventopening of the jaws when a cover is in raised position.

12. In a soaking pit cover crane including a bridge adapted to span a'plurality' of soaking pits each having an individual cover, in combination, a trolley mounted on said bridge, means for moving the trolley on the bridge to position it over a selected pit, a pair of lifting arms depending from the trolley, motor means on the trolley for raising or lowering said arms simultaneously, gripping means carried by said arms for cooperating with gripping members on the pit covers to operatively connect the arms with the cover over which the trolley is positioned whereby the cover may be raised or lowered by said motor means. each of said gripping means comprising a pair of jaws operative when closed to grip said member, means on the trolley for opening and closing said jaws, and means on the bridge for controlling said jaw operating means.

13. In a soaking pit cover crane including a bridge adapted to span a plurality of soaking pits each having an individual cover, in combination, a pair of lifting arms depending from the bridge above each of the pits, motor means on the bridge for raising or lowering said arms simultaneously, gripping means carried by each arm for cooperating with a gripping member on the pit cover above which the arm is positioned to operatively connect the arm and the cover whereby the cover may be raised or lowered by said motor means, said gripping means comprising a pair of jaws operative when closed to grip said member, jaw actuating means individual to each pair of arms for opening or closing the jaws, and means for'operating said actuating means selectively.

14. The combination with a group of soaking pits arranged in a plurality of parallel rows, each of said pits having an individual cover, of a crane adapted for handling the cover of any pit in the group comprising, a bridge, a track supporting said bridge for movement transversely of the rows of pits, motor driven means for moving said bridge on said track into a position to span any selected row of pits, means on said bridge for raising and lowering pit covers, gripping means for detachably connecting the pit covers with said raising and lowering means, and control means for operating said gripping means to connect with the cover of any selected pit in the row spanned by said bridge.

15. The combinationwith a group of soaking pits arranged in a plurality of parallel rows, each of said pits having an individual cover, of a crane adapted for handling the cover of any pit in the group comprising, a bridge, a track supporting said bridge for movement transversely of the rows of pits, motor driven means for moving said bridge along said track into a position to span any selected row of pits, means on said bridge for raising and lowering pit covers, gripping means for detachably connecting the pit covers with said raising and lowering means, motor driven means for operating said raising and lowering means, and a centralized control station for controlling both of said motor driven means and for operating said gripping means. 16. The combination with a group'of soaking pits arranged in a plurality of parallel rows, each of said pits having an individual cover, of a; crane adapted for handling the cover of any pit in the group comprising, a bridge, a track supporting said bridge for movement transversely of the rows of pits, motor driven means for moving said bridge along said track into a position to span any selected row of pits, means on said bridge for raising and lowering pit covers, gripping means for detachably connecting the pit covers with said raising and lowering means, motor driven means for operating said raising and lowering means, means for operatively associating said gripping means with the cover of any selected pit in the row spanned by said bridge, and remote control means for operating said gripping means to grip or release said cover.

CHRISTOPHER HENRY SCI-IRAMM.

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