US2479411A - Material handling apparatus - Google Patents

Description

Aug. 16, 1949. w. RUDDOCK 2,479,411

" MATERIAL HANDLING APPARATUS Filed April 21, 1944 7 Sheets-Sheet 1 W/ZL/AM 19100004 INVENTOR.

ATTORN EY.

1949. A w. RUDDOCK 2,579,411

, MATERIAL HANDLING APPARATUS Filed April 21, 1944 7 Sheets-Sheet 3 ATTORNEY.

lNvE NTOR. mLL/AM Buoo oaz,

Aug. 16, 1949. w. RUDDOCK 2,479,411

MATERIAL HANDLING APPARATUS Filed April 21; 1944 '7 Sheets-Sheet 4 W2; [AM Eupoocz,

INVENTOR.

ATTORN EY.

1949- w. RUDDOCK 2,479,411

MATERIAL HANDLING APPARATUS Filed April 21, 1944 7 Sh eets Sheet 5 3 INVENTOR.

VWM/AM Bannock,

' ATTORNEY.

W. RUDDOCK MATERIAL HANDLING APPARATUS Aug. 16, 1949.

- '7 Sheets-Sheet 6 Filed April 21, 1944 WZLL/AM :JQUDDOCK, INVENTOR.

ATTORN EY.

g- 1949- w. RUDDOCK 2,479,411

MATERIAL HANDLING APPARATUS 7 Sheets-Sheet 7 Filed April 21-, 194-4 INVENTOR. W lLL/AM .Euooocz,

A TTOQA/EY.

Patented Aug. 16, 1949 MATERIAL HANDLING APPARATUS William Ruddock, South Pasadena,

Calif.;

Braeme E. Gigas, executor of said William Ruddock, deceased, assignor to H. V. Griifitts, Leslie E. Edwards, Jr., and Paul Weilein, as trustees for benefit of Annie Downey, Susan Falkner, Bernardine Thernstran, Dolly Schultz, Elaine Welby, Joyce Edwards, and Leslie E. Ed-

wards, Jr.

Application April 21, 1944, Serial No. 532,119

10 Claims. 1

This invention relates to material handling apparatus; more particularly, it relates to such apparatus of the type commonly known as clam shell buckets.

It is an object of this invention to provide a clam shell bucket arranged for operation by a single hoisting line. While it may be desirable to provide a hoisting line in two or more parts passed about suitable sheaves to increase the lifting force of the line, or a doubled line for heavy loads, such obviously constitutes in effect a single line as compared with a hoisting or closing line and a holding line arranged to be operated by independently controlled Winding drums, which are usually required for clam shell buckets.

It is another object of this invention to provide a single line clam shell bucket having improved means for controlling the opening and closing movements of the bucket sections.

It is another object of this invention to provide a single line clam shell bucket in which the opening and closing movements of the bucket sections are controlled entirely by operation of the hoisting line.

It is another object of this invention to provide a single line clam shell bucket having improved means for controlling the speed of opening of the bucket and hence the rate of discharge.

As a means of providing control over the movements of the bucket sections to load dumping position or to load retaining position, it is proposed to utilize a drum which rotates in accordance with such movements and to control the rotation of the drum by brake mechanism which is normally conditioned to prevent such operation. It is thus a still further object of this invention to I provide an improved brake mechanism for such purpose.

Material handling equipment, especially buckets of the character under discussion, are subject to severe shocks which cause high and damaging stresses in the hoisting cable. For example, during a closing operation in fairly soft material, the bucket may encounter a large rock, a piece of timber or other unyielding substance, resulting in a sudden arrest of such closing movement and imparting a severe jerk to the cable without foreknowledge of the operator. or it may be necessary for the operator to intentionally apply sudden forces to the bucket by means of the hoisting cable to cause the bucket to close under certain conditions, or to free it from some kinds of material, such for example as clay. It is thus, accordt ingly, another object of this invention to provide me ns .fo pr ve t su e and e cess ve m 2 creases in the tension of the hoisting cable incident to operation of the bucket.

In using clam shell buckets or the like, it is common to provide a pair of lines for supporting the bucket, which are joined to means such as a hook plate adapted to engage a hook member operated by a derrick'crane or similar apparatus for raising and lowering the bucket. Heretofore it has been difiicult to so arrange such lines so that they are substantially equally tensioned. Thus, it is a still further object of this invention to provide an improved means of attachment for such lines, wherein the lines are readily subjected to equal tension.

This invention possesses many other advantages and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a number of forms in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

In the drawings:

Figure 1 is a side elevation of a clam shell bucket embodying one form of the invention;

Figure 2 is an elevation on an enlarged scale of the right hand side of the structure of Figure 1, taken as indicated by line 2-2 of Figure 1;

Figure 3 is a section on an enlarged scale taken on line 33 of Figure 1;

Figure 4 is a section taken on line 4-4 of Figure 3;

Figure 5 is a top plan view of a portion of the structure of Figure 3, taken as indicated by line 5-5 of Figure 3;

Figures 6 and 7 are views similar to Figure 1, but showing different operating positions of the bucket sections;

Figure 8 is a view similar to Figure 1 showing a modified form of the invention;

Figure 9 is an elevation on an enlarged scale of a fragment of the right hand side of the structure of Figure 8, taken as indicated by line 9-9 of Figure 8;

Figure 10 is a section as seen on line ill-l0 of Figure 9, but showing the parts in a diiierent operating position;

Figures 11, 12 and 13 are views illustrating different operating positions of the structure of Figure 8.;

3 Figure 14 is a side elevation showing another modified form of the invention;

Figure 15 is a view showingad-ifferent operating position of the structure of Figure 14;

Figure 16 is a vertical section on an enlarged scale taken on line I6-I6 of Figure 15;

Figure 17 is a side elevationof still anQther form of the invention;

Figure 18 is a view showing a different operating position of the structure ofFigure 1'7; and,

Figure 19 is a detail elevation taken as indicated by line I9I9 of Figure 18.

Referring to Figures 1 m5 of the drawings, a material handling bucket I is ,shown therein, which in so far as the details of the bucket are concerned is of conventional construction, and comprises a pair of complementary bucket sections or members 2 and 3 pivotally joined for movement with respect to each other at 4. For this purpose sections 2 and 3 are provided respectively on their opposite sides with means forming extensions-or arms '5 and 6 which overlap at their upper ends, as shown in Figure 2. The'upper ends of one pair of arms, for example the arms 6, are connected by a transverse tie member 1 suitably fixed to the arms 6 and having projections 8 forming trunnions for engaging the other arms 5, and forming the pivotal joints 4 between the bucket sections 2 and 3.

Each bucket section 2 and 3 is provided adjacent its outer corners :with pairs of cars I and II respectively. A bail structure I2 formed of links I3 joined'by a platform M at their upper ends, is secured to one of the sections, as that indicated by 3, by having the lower end of each of the links I3 pivotally secured between adjacent pairs of ears II. For this purpose a bar or shaft It extends transversely across the bucket section and between the ears 'I I. A pair of links I5, I5, similar to the links I3, are pivotally joined tothe ears I!) as by short pins I6 extending between each pair of ears, the upper ends of the links I being pivotally joined respectively to the upper ends ofthe'links. I3;at;I'I. Provisions are made for attaching the bucket I to a hoistin means, as line I8, asseme place near the connection I1 between the pairs of links I3 and I5.

The described arrangement is such that the bucket sections 2 and-3 tend to swing apart about their pivotal connection 4 and assume the .open position of Figure. 6. The proportions and. arrangement of the parts maybe such as to assure that such a complete opening movement occurs, or the tie member I may bev made of substantial weight, as by having an enlarged central portion la,.to ensure such complete opening. To appropriately limit .the swinging Qf the bucket sections 2 and 3 .to, open position, stop members 2| may be provided on one pair or the bucket sections, for example arms 6 arranged to engage the shoulders 22 on the other arms, as arms '5, when the bucket sections reach the open position of Figure 6.

For operating such a bucket, it is obviously necessary to supply means for optionally preventing such opening movement and for causing the bucket sections 2 and 3 to approach each other and close for the purpose of picking up and retaining a load. Furthermore, it is desirable that the means provided for maintaining the bucket closed should make it possible to regulate the extent and speed of the bucket opening, thus controlling the rate at which the load is discharged from the bucket.

This may be convenientl done by providing an operating connection between the hoisting line and the bucket, permitting relative movement optionally between the hoisting lin and the bucket sections. Thus when relative movement is permitted, the bucket is opened or dumps; when relative movement is prevented, the bucket is maintained closed while raised or lowered, or upon hoisting of the line, the bucket is caused to close.

For this purpose a control arm structure 25 is provided which is pivotally secured at one end 26 to one of the bucket sections, the opposite end 27 being operatively connected to the hoisting line I8, so that the arm 25 is positioned about said pivotal connection by the hoisting line. The arm 25 is connected at a point intermediate its ends 26 and 21 with the connection 4 between the bucket sections 2 and 3 as by mechanism 28, which mechanism includes means controlling the distance between the arm and this connection 4. In this way the opening and closing movements of the bucket sections 2 and 3 are controlled. Thus, with the bucket I suspended by th line I8, the arm 25 is maintained in the generally upwardly directed position of Figure 1, and by operating the mechanism 28 to maintain this distance at a minimum, the bucket is maintained closed. By allowing this distance to increase the bucket sections are permitted to separate to load dumpin position. By supporting the opened bucket otherwise than by line I8, as by resting the opened sections on the ground, the control arm 25 may be caused to approach the connection 4 by slacking the line I8. Then by actuating the mechanism 28 to prevent-an increase in the distance between the arm 25 and connection 4, and by hoisting on the line I8 to swing the control arm 25 upwardly about the connection 26, the bucket sections may be returned to closed posi tion.

- The details of the arm structure 25 will now be described. This structure 25 comprises a pair of spaced parallel members 36 and 3i (Figure 2), joined near their upper ends by a cross member 32 and near their lower ends by a tubular cross member 33 by means of which the structure 25 is swingably mounted on the transverse shaft I4. Since it is desirable to apply a larger force operating at a lower speed to close the bucket as compared with the force for lifting the bucket, the hoisting line I8 is arranged to act as a two part line while moving the control arm 25, as by passing about a sheave on the arm and is anchored to the bucket. Thus, when the arm reaches the limit of its movement, the sheave no longer acts to cause the line to operate as a two part line. Thus, a shaft 34 extends between the upper ends of the members 30 and 3| serving to rotatably support a pair of sheave wheels 35. Hoisting line I8 is shown as a double line, passing from a point of attachment I8a on one side of an apertured hook plate I9 over one of the sheaves 35 to a point of attachment 36 on the bucket, and thence over the other sheave 35 back to the other point of attachment I8b on the opposite side of the plate I9 (see Figures 2' and 7).

As shown in Figure 7, the plate I9 is adapted to be supported by a hook 29 inserted through the aperture IB-a of the plate I9. In this way the bucket may be readily attached to any suitable crane, derrick, or other hoisting apparatus for operation thereby, and may be removed when it is desired to use such equipment for other purposes. The attachment'means 36 preferably ineludes shock absorbing means, to be presently described.

The mechanism 28 for controlling the movement of arm structure 25 with respect to the bucket sections includes a. spring driven winch of the general type disclosed either in my copending application entitled Control mechanism for material handling apparatus, filed June 8, 1943, Serial Number 490,006, and now abandoned, or in my Patent Number 2,166,479, issued July 18, 1939 and entitled Tagline Device. Thus,'the mechanism 28 includes a drum 39 rotatably supported on a shaft 40 extending between the arms 38 and 3| and fixed thereto, as by being mounted in brackets 42 and 43 secured respectively to the arms (see Figure 3). A doubled cable 44 is anchored to the drum 39 at 45 and extends over the sheaves 46 to the transverse member I to which it is suitably attached at 41. Movement of the bucket sections 2 and 3 from the closed position of Figure 1 to the open position of Figure 6 will thus cause the drum to rotate in a counterclockwise direction. Brake mechanism 50 is provided to optionally control or prevent such rotation of the drum, and hence to control the opening movement of the bucket sections.

The brake mechanism 50 is shown in Figures 3, 4 and 5 and comprises a brake drum 5| which for the present may be considered as fixed to the winch drum 39. Since the brake 50 is relied on to maintain the bucket sections in load carrying position, it is preferred to arrange the brake to be normally engaged to prevent rotation of the drums 39 and 5|, and to provide means for releasing the brake when it is desired to allow the drums to rotate.

A brake band 52 substantially entirely encircles the drum 5| and is secured against ro tation therewith as by links 53 pivotally secured to lugs 54 adjacent one end of the band 52 and to a bracket 55. The other end of the band 52 has an upstanding ear 56 thereon, through which pass headed parallel rods 51 and 58, these rods also passing through clearance openings 59 in a transverse web wall 60 of the bracket 55. A compression spring 6| is adjustably confined on each of the rods 51 and 58 between the wall 60 and a nut 62 threaded on the end of the rod. The force of the springs 6| is caused to act on the ear 56 to contract the band 52 about the drum 5|, by heads 63 and 64 respectively on the rods 51 and 58 and engaging the car 56. By adjusting the nuts 62, the force exerted by the springs 6| tending to contract the band 52 and hence the restraining force exerted by the band 52, may be appropriately adjusted.

For releasing the band 52, a cam 61 is provided between the car 56 and the wall 60, mounted on a shaft 68 rotatably supported in the bracket 55 and having an operating lever 69 secured thereto. A cam follower I is slidably supported on the rods 51 and 58 and is adapted to engage an adjustable abutment H on the ear 56, formed by a member 12 threadedly engaging a nut I3 welded to the ear 56. From an inspec- (3 tion of Figure 4, it will be readily apparent that with the cam in the released position shown, the brake band is in engagement with the drum by virtue of springs 6|, and by rocking the cam 61 to the left, the cam follower will be engaged and the brake band 52 expanded to release the drum 5|.

As so far described the arrangement of the brake 50, and the drum 39 would be effective to maintain the bucket sections 2 and 3 in closed or load carrying position, and release of the brake 50 would allow the sections to open to loading or load discharging position. However, to provide for moving the sections to closed position, means must be provided for rewinding the cable 44 on the drum 39 after it has been unwound to open the sections. For this purpose, means are provided which continually urge the drum 39 to rotate in cable winding direction. Since the force exerted by such means acts in opposition to the force tending to open the bucket, it is obvious that the force tending to wind the cable should be relatively light and under no conditions capable of nullifying the bucket opening force.

Thus, referring to Figure 3 and particularly to Figure 4, it will be seen that the drum 39 is tubular, its ends being closed respectively by heads 15 and 16, suitably secured to the drum and provided with hubs H and 18. Within the drum 39 is a torsion spring 89 arranged to urge the drum 39 as indicated by the broken arrow 8| in Figure 1, and 82 in Figure 4. One end, as 83, of the spring is arranged to rotate with the drum 39 as'by being attached to'a lug 84 on the hub 11. The other end 85 of the spring 86 is fixed against rotation by attachment to a lug 86 formed on a sleeve 81. Sleeve 81 is supported at one end on the exterior of the hub 18 and at its other end by a spacer 88. A diametrical pin 89 extends through the shaft 40, the sleeve 81 and spacer 88, serving to hold the sleeve 81 and the end 85 of the spring 89 against rotation with respect to the shaft. I

As the drum 39 is rotated in the direction of the full arrows, 93 in Figure 1 and 94 in Figure 4, in a bucket opening operation, the spring 80 is wound to increase the tension therein. When the arm 25 is lowered to the position of Figure 7 preparatory to closing the bucket, the bucket being otherwise supported as by resting on the surface of the ground, the drum 39 is rotated by the spring 80 in the direction of the broken arrow 95 of Figure 7 and 82 of Figure 4 to re- "wind the cable 44 onto the drum to maintain the cable free of slack. To permit proper adjustment of the spring tension, the head 15 carrying the ing 84 is detachably secured to the drum 39 by bolts 90. Detachment of the head from the drum permits angular movement thereof with respect to the shaft 40 and the lug 86, thus altering the tension in the spring 30. After such adjustment, the head 15 is replaced on the drum.

To permit such rewinding of the cable 44, the brake 50 must of course be released to permit the'drum 39 to be rotated by the spring 80. To obviate the necessity of releasing the brake 59 (which is normally engaged) for such purpose and thus greatly simplify the operation of the bucket, the brake mechanism 59 is connected to the drum 39 through a one way clutch mechanism, so that the brake is only capable of controlling the rotation of the drum 38 to allow unwinding of the cable 44 to cause the bucket to open, the drum 39 being free to rotate in cable winding direction in response to the spring 80 at all times regardless of the brake. Referring to Figure the brake drum 5! is freely rotatable on the shaft 40, being axially confined between the bracket 43 and the head 16. The drum 5| is provided with internal ratchet teeth 96 adapted to be engaged by a plurality of pawls 91 pivotally mounted on pins 98 carried by head 16 and a ring 99 spaced therefrom on the drum 3'1, and. urged outwardly to engage the teeth 98 by springs I00. As clearly shown in Figure 4, the ratchet teeth" ligand the pawls 91 are so arranged as to engage upon any rotation of the drum 39 in the direction of the arrow es corresponding to tensioning of the cable M; th-us such rotation of the drum 33 will depend upon the rotation of the brake drum SI and be controllable by the brake so. On the other hand, any slackening oi the cable 44 will permit the drum 39 to rotate in the opposite direction, as indicated by the arrow 32, in response to the spring 39, regardless of the brake 52, since such rotation will cause disen= gagement of the pawls 37 from the ratchet 95. Thus, by the use of such a clutch it is only necessary to maintain the brake B disengaged during the opening of the bucket, subsequent rewinding of the cable occurring automatically.

It may be desirable to provide mechanism so that the bucket opening as well as the closing can be controlled solely by the hoisting line and without supplementary control means and the need of operating these. Such an arrangement is shown in Figures 8 to 13. Therein are shown cooperating members, operable into and out of engagement to control rotation of the drum and hence the opening of the bucket, by movement of the arm-structure in response to operation of the hoisting line.

Referring particularly to Figures 8, 9 10, a bucket I is shown which is substantially identical with the bucket previously described, comprising bucket sections 2 and 3 pivotally joined at 5 and having the upwardly extending pivoted links I 3 and I5 and the control structure 25 by means of which the hoisting cable is is connected to the bucket. A spring urged drum 39 is also provided as before for controlling the movement of the bucket sections between open and closed positions by means of a cable lit. However, "in this form of the invention the rotation of the drum .59 with respect to the arms 3E and t! of the control arm structure 25 is contro'lled by ratchet and pawl members no and II The member H9 comprises a wheel secured on the drum 39 for rotation therewith adjacent the head I5 with ratchet teeth H2 formed on its pe riphery. The member III comprises a pawl mounted for free movement into and out of engagement with the teeth IE2 by being rotatably mounted on a pin I I3 secured in a bracket I I4 on the'arm 3!). The arrangement is such, that when the pawl II! is in engagement with any one of the teeth II2, rotation of the drum 39 in bucket opening direction is prevented, but by appropriate movement of the control arm 25, the pawl I I I may be disengaged from the wheel II B. Since gravity plays an important part in the operation of the pawl I I I, it may be convenient to refer to this pawl as a gravity pawl or gravity latch.

As clearly shown in Figure 10 and also in Figure 8, the tendency of the drum 39 to rotate counterclockwise and which is resisted by the ratchet members II!) and III, acts to maintain the gravity latch III in engagement with the ratchet member H3 and thus securely holds the bucket closed during any raising or lowering movement. When it is desired to open the bucket to load discharging or loading position, the bucket I is supported otherwise than by the hoisting line I8, as for example by lowering the bucket to rest on the ground, the stockpile or the like, as shown in Figure 1 1, and line 18 is .slacked. This allows the control arm to swing downwardly about its pivoted end 26, slacking the cable 44. This slack .is immediately taken up by a slight clockwise movement of the drum .39 under the urging of-the spring 80, which movement frees the latch III from the teeth I l2 allowing it-to swing downwardly by gravity aboutits pivot II3, to the position shown in Figures 11 and 12. Drum 39 is now free to rotate in response to tension in the cable 44, and if the bucketis raised by line I8, the bucket sections will swing apart to open position as shown in Figure 12.

When it is desired to close the bucket, it is ap-- propriately supported as on the ground and line it operated to lower the control arm 25 to near the transverse member I, the spring acting to rotate the drum 39 to rewind the cable 44, as discussed in connection with Figure 7. The pin I I 3 is so located that as the arm 25 reaches a desired low point, the latch I I I swings by gravity into reengagement with the ratchet member IIEl, serving to prevent unwinding of the cable 44 fromthe drum 39 as the arm 25 is swung upwardly by the hoisting line I8, (see Figure 13). Thus, the bucket is closed as shown in Figure 8 and then lifted.

With the automatic dumping arrangement just described, the opening of the bucket and resulting discharge of the load may be undesirably rapid. To desirably control the rate of such opening, the brake mechanism II5 may be provided for the drum 39. This brake mechanism may be substantially identical with the brake mechanism 59 including a one way clutch to permit rewinding of the cable. However, in such automatic operation, the springs 6| would be so adjusted as to cause the brake to exert only suiiicient force to prevent undue rapidity of the bucket opening. a

Means are provided for rendering the pawl I i I inactive if desired, so that the operation of the bucket may be controlled by the brake mechanism I I5, as in the'first described form. For this purpose, a set screw IIIa is threaded into the bracket H4 and may be screwed inwardly thereof to engage the pawl I I land maintain it against movement into engagement with the ratchet member "I I 0 (see Figure 10) As previously mentioned, equipment or the character under discussion is subject to severe shocks which produce dangerous stresses in the hoisting cable and winding mechanism. Thus, the means 36 which serves to operatively secure the hoisting cable I8 to the bucket may desirably include shock absorbing -means interposed between the bucket and the cable. As clearly shown in Figure 2, an upwardly convex saddle I20 having a depending tubular section I2I near each end passing downwardly through suitable openings 122 in platform I4, is resiliently supported on the platform by helical springs I23 mounted in cup-s I24. If desired, spacer rings I25 may be provided to maintain the springs against lateral deflection.

The cable I8 passes upwardly from one of'the sheaves 35 through the tube I2I at the adjacent end of the saddle I 20, over the saddle I26, and thence down through the other tube IZI to the other sheave 35, and is freely slidable over the saddle I20. Tension in the cable obviously compresses the springs I23, thus sudden shocks imparted to the bucket are cushioned by these springs before reaching the hoisting line. The double line I8 is used principally to provide spaced points of support for the bucket, resulting in increased stability.

Furthermore, the tension in the two reaches of line I8 is maintained substantially equal at all times, regardless of wear on the parts or the ca- 9 I r 'bl, since the cable is freeto slide over the saddle I29. This greatly facilitates installation of the cable I8 and its attachment to hook plate I9, since it is not necessary to initially equally tension the two reaches of the cable. A guide clip I26 is provided to retain the cable I8 against accidental displacement from the saddle I 29.

It is not necessary that the mechanism 28 for connecting the arm structure 25 and hence cable I8 to the bucket I, be mounted on the arm structure; it can be mounted on the bucket structure equally as well. Such an arrangement is illustrated in Figures 14, 15 and 16.

Therein a bucket is shown which is substantially indentical with that of the previously discussed forms, including a pair of complementary sections 2 and 3 pivotally joined at 4 by a transverse member 'I and having a bale structure I2. A control arm I30 is pivoted at its lower end I3I to one of the bucket sections as for example the section 3. The upper end I32 of the arm I39 carries the sheaves 35 about which the cable I8 passes for attachment to the means 36. The arm I30 comprises a pair of spaced side members I33 and I34 between which the sheaves 35 are pivotally mounted, and is adapted to swing about its lower end I3I in response to operation of the cable I3, all as before.

The mechanism I35 for connecting the arm I39 with the bucket sections 2 and 3 includes a drum I36 rotatably mounted on the transverse member I as by brackets I31 and I38 and controlled by brake mechanism I39. The drum I36 is spring driven in the same manner as the drum 39 of the first form and is similarly connected with the drum of the brake mechanism I39 by a one way clutch, brake mechanism I39 being normally engaged as before to prevent rotation of the drum.

now in the broken line position of Figure 15.

Upon relaxation of the cable I8, the arm I 36 swings downwardly to the full line position and the drum I36 is caused to wind the cable I 4| as before. Upon return of the arm I36 to its upper position, the drum I36 will be restrained by the brake I33, and the bucket sections 2 and 3 will b: swung upwardly to closed position by the cable I I.

The arm structure can even be omitted. In Figures 1'7, 18 and 19, a bucket structure I is shown, having a spring winding drum I36 rotatably mounted on transverse member I and controlled by the brake mechanism I39, as in the form just discussed. The cable I8 passes about a pair of sheaves I45 (see Figure 19) carried by a travelling block structure I46 to its point of attachment on the bucket I at 36. A cable I41 corresponding to cable I4I of the previous modification is suitably secured on the drum I36 and is attached to the travelling block I 46 at I48. The operation of the bucket I by hoisting line I8 in response to the rotation of the drum I36 as controlled by the brake I39 is the same as before.

I claim:

i 1. In a single line bucket including complementary bucket sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, a control arm pivoted to one of said sections and adapted to be swung about its pivot by operation of the hoisting line, means urging said bucket sections to load discharging position, means operatively connecting said am and the bucket sections including a drum so arranged that movement of said sections to load discharging position causes the drum to rotate in one direction, means urging the drum to rotate in the opposite direction, means normally preventing rotation of the drum in said one direction for maintaining said sections in load retaining position but permitting the drum to rotate freely in the opposite direction, and means to release optionally the means preventing rotation of the drum in said direction to permit the bucket sections to move to load discharging position.

2. In a single line bucket including complementary bucket sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, a control arm pivoted to one of said sections and adapted to be swung about its pivot by operation of the hoisting line, means urging said bucket sections to load discharging position, means operatively connecting said arm and the bucket sections including a drum so arranged that movement of said sections to load discharging position causes the drum to rotate in one direction, means urging the drum to rotate in the opposite direction, a normally engaged brake, and one way clutch means connecting the brake and said drum, whereby said brake is effective to prevent rotation of the drum in only said one direction for maintaining said sections in load retaining sitions, means urging said sections to load discharging position, a control arm pivoted to one of said sections for movement with respect to said section, a drum rotatably mounted on said arm and constantly urged to rotate in one direction, a flexible member operatively connecting said drum with said bucket sections whereby as said sections move to load discharging position said drum is caused to rotate in a direction opposite to said one direction, brake mechanism for controlling rotation of said drum, and one way clutch means connecting said brake mechanism with the drum, whereby the brake mechanism affects rotation of the drum in said opposite direction only and said drum is free to rotate in said one direction at all times to maintain said flexible member free of slack for any position during movement of the arm with respect to the bucket sections.

4. In a single line bucket including complementary bucket sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, an arm pivoted to one of said sections, and arranged to swing about its pivot in response to operation of the hoisting line, means urging said bucket sections to load discharging position, a drum rotatably carried by said arm, a flexible member connecting said drum and said bucket sections, whereby movement of said sections to load discharging position causes the drum to rotate in one direction, a brake mechanism, one way clutch means operatively connecting said brake mechanism and said drum whereby said mechanism can control the rotation of the drum only in said one direction, and means continuously urging the drum to rotate in the opposite direction, the iorce exerted by the means urging the sections to load discharging position being capable of causing the drum to rotate against the force exerted by said urging means.

5. In a single line bucket including complementary bucket sections pivotally joined formovement with respect to each other between load retaining and load discharging positions, a control arm pivoted to one of said sections and adapted to be swung about its pivot by operation of the hoisting line, means urging said bucket sections to load discharging position, a drum rotatably carried by the control arm, means operatively connecting said drum and the bucket sections, whereby movement of the sections to load discharging position causes the drum to rotate, a ratchet wheel operatively joined to the drum, a gravity pawl for cooperating with the ratchet mounted for free swinging movement on said arm, said pawl in one extremity of movement of the arm being urged into engagement with the ratchet and in the other extremity of movement of the arm being urged out of engagement with the ratchet. V

6. In a single line bucket including complementary bucket sections pivotally 'joined for movement with respect to each other between load retaining and load discharging positions, a control arm pivoted to one of said sections and adapted to be swung about its pivot by operation of the hoisting line, means urging said bucket sections to load discharging position, a drum rotatably carried by the control arm, means operatively connecting said drum and the bucket sections, whereby movement of the sections to load discharging position causes the drum to rotate, a one way clutch mechanism including a pair of relatively movable members, the movement of one member serving to control movement of the other member, said other member being fixed to the drum, and means for controlling the movement of said one member whereby to control rotation of the drum.

7. In a single line bucket including complementary bucket sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, an arm pivoted to one of said sections, and arranged to swing about its pivot in response to operation of the hoisting line, means urging said bucket sections to load discharging position, a drum rotatably carried by one of said sections, a flexible member connecting said drum and said arm, whereby movement of said sections to load discharging position causes the drum to rotate in one direction, a brake mechanism, one way clutch means operatively connecting said brake mechanism and said drum whereby said mechanism can control the rotation of the drum only in said one direction, and means continuously urging the drum to rotate in the opposite direction, the force exerted by the means urging the sections to load discharging position being capable of causing the drum to rotate against the force exerted by said urging means.

8. In a single line bucket including complementary bucket sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, a control arm pivoted to one of said sections and adapted to be swung about its pivo't by operation of the hoisting line, means urging said bucket sections to load discharging position, a rotatable drum, means operatively connecting said drum and the bucket sections as well as means operatively connecting said drum and said arm, whereby movement of the sections to load discharging position causes the drum to rotate, a one way clutch mechanism including a pair of relatively movable members, the movement of one member serving to control movement of the other member, said other member being fixed to the drum, and means for controlling the movement of said one member whereby to control rotation of the drum.

9. In a single line bucket including complementary bucket sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, a member movable in response to operation of the hoisting line, means urging said bucket sections to load discharging position, a rotatable drum, means operativel connecting said drum and the bucket sections as well as means operatively connecting said drum and said movable member, whereby movement of the sections to load discharging position causes the drum to rotate, a one way clutch mechanism including a pair of relatively movable members, the movement of one member of said one way clutch serving to control movement of the other clutch member, said other clutch member being fixed to the drum, and means for controlling the movement of said one clutch member whereby to control rotation of the drum.

10. In a single line bucket including complementary sections pivotally joined for movement with respect to each other between load retaining and load discharging positions, a member movable in response to operation of the hoisting line, means urging said bucket sections to load discharging position, a drum rotatably carried by one of said sections, a flexible member connecting said drum and said movable member, whereby movement of said sections to load discharging position causes the drum to rotate in one direction, a brake mechanism, one way clutch means op eratively connecting said brake mechanism and said drum whereby said mechanism can control the rotation of the drum only in said one direction, and means continuously urging the drum to rotate in the opposite direction, the force exerted by the means urging the sections to load discharging position being capable of causing the drum to rotate against the force exerted by said urging means.

WILLIAM RUDDOCK.

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

UNITED STATES PATENTS Number M Name Date 937,496 Williams Oct. 19, 1909 1,385,520 Corneloup July 26, 1921 1,595,568 Norris Aug. 10, 1926 1,717,549 Brosius June 18, 1929 1,727,825 Harrington Sept. 10, 1929 1,798,504 Straub et a1 Mar. 31, 193i FOREIGN PATENTS Number I Country Date 522,854 GreatBritain June 28, 1940

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