US2414771A - Distributing apparatus for concrete mixers - Google Patents

Description

Jan.v2l, 1947. s. SHAFER, JR 2,414,771

DISTI'I'CIIBU'I'ING APPARATUS FOR CONCRETE MIXERS Filed Jan. 16, 1945 2 SheetS-Sheet l 3mm Samuel Skcjr, J1,

Jan. 21, 1947.

s. SHAFER, JR

DISTRIBUTING APPARATUS FOR CONCRETE MIXERS Filed Jan. 16, 1945 2 Sheets-Shet 2 Samuel S/ujr, J21,

Patented Jan. 21, 1947 DISTRIBUTING APPARATUS FOR CONCRETE MIXERS Samuel Shafer, Jr., Milwaukee, Wis., assignor to Chain Belt Company, Milwaukee, Wis., a corporation of Wisconsin Application January 16, 1945, Serial No. 573,035

6 Claims. 1

The invention relates to distributing apparatus for concrete mixers, and more particularly to apparatus of the boom-and-bucket type widely employed in connection with mixers especially designed for use in the construction of concrete roads and pavements, and has for its principal object the improvement of the mechanism for controlling the operation of the discharge doors or gates of the bucket.

In concrete mixing apparatus of the character indicated, it has long been common practice to provide an operator's station on the mixer proper, from which substantially all of the functions of the machine may be controlled. Among these functions are the outward and inward traverse of the bucket along the boom, as well as at least the opening of the discharge doors of the bucket. The mechanisms for controlling these latter functions have been developed along two general lines, according to one of which the bucket doors are retained in closed position by some form of detent, from which release is secured by a pull upon the traverse cable tending to move the bucket inwardly along the boom, when it is desired to discharge the bucket contents. Usually there is some form of lost motion connection between the traverse cable and the bucket which permits the detent to remain operative during outward traverse of the bucket, but which, upon reversal of the motion of the cable to draw the bucket inwardly, trips the detent whereby the doors may open by gravity. My prior Patent No. 1,451,308 granted April 10, 1923, disclosesa control of this character.

With this type of mechanism, however, once the doors are opened, the operator has no further control over them until the bucket is returned to its loading position at the inward end of the boom-which action usually automatically closes and relatches the doors-and as a result the entire contents of the bucket are discharged upon the road bed with only such distribution or spreading thereof as may be accomplished through traverse of the bucket in one direction or the other along the boom during discharge.

The second type of control referred to above and typified in my prior Patents No. 1,729,553 granted September 24, 1929, and No. 1,805,602 granted May 19, 1931, employs an auxiliary cable or tag line to secure opening of the bucket doors. This form of control gives the operator some degree of control over discharge of the bucket contents after the doors are once opened, since by reversal of the direction of travel of the bucket, the doors may be again closed prior to complete discharge of said contents. However, although this type of mechanism gives the operator better control over the discharge of the bucket than does the first type, it still can be accomplished only through traverse of the bucket on the boom.

The first mentioned type of control has certain constructional and operating advantages over the second type, and these are preserved by the mechanism of the present invention, which at the same time provides a simple and positive control over the opening and closing of the bucket doors, effective at all times and under all conditions, through manipulation of the traverse cable itself, without the use of a tag line. i

In the accompanying drawings forming a part of this specification there is illustrated two forms of apparatus suitable for attaining the objects of the invention, although as will be readily understood by those skilled in the art, various modifications thereof may be made Within the scope of the invention, as defined by the appende claims.

In the said drawings:

Figure 1 is a side elevational view, partly broken away and in section, of the essential elements of a well known example of boom-andbucket distributing apparatus for a paving mixer, with one form of bucket door control mechanism constructed and arranged in accordance with the present invention applied thereto, the parts being shown in the positions occupied when the doors are closed;

Fig. 2 is a view similar to Fig. 1 but showin the parts in the positions assumed when the doors are open; and i Fig. 3 is a plan view, largely diagrammatic, illustrating a modification whereby control of the doors may be effected through manipulation of the winding drums upon which the bucket traverse cables are wound. l

Referring more particularly to Fig. l thereis shown a portion of the discharge end of a paving concrete mixer, comprising a framework H mounted upon crawler treads l2 for ground traverse and having a mixing drum l3 mounted upon rollers M for rotation about a horizontal axis. The frame ll carries a bracket which supports a vertical bearing member Iii in which is journalled a vertical pivot sleeve ll to the lower end of which the inner end of the boom 18 is connected by a horizontal pivot pin 9. The upper end of the sleeve member ll carries a worm gear 20 arranged to be reversibly driven at will from a transmission mechanism 2| whichin turn is driven from the drum l3 by a chain and sprocket drive 22.

The boom l8 comprises a pair of parallel laterally spaced oppositely facing channel irons, upon which the wheeled bucket carriage or trolley 23-is mounted for longitudinal travel back and forth, and from which carriage the bucket 24 is hung. Outward travel of the bucket along the boom, i. e. from right to left, as viewed in Fig. l, is accomplished by means of a cable 25, one end of which is attached to the carriage or trolley 23 by a bail 26, from whence the said cable extends outwardly to and partly around a sheave 21 mounted on the outer end of the boom. From the sheave 21 said cable extends inwardly above the boom to an idler pulley 28, thence beneath and partly around one of a pair of sheaves 29 mounted on the horizontal pivot pin l3. From the sheave 29 the cable passes upwardly through the tubular pivot sleeve I! to a winding drum 30 mounted on the framework H, to which drum the other end of the cable is made fast. The drum 30 is or may be of the general type disclosed in prior Patent No. 2,230,478 granted February 4, 1941, and may be reversibly driven from the transmission mechanism 2! by a chain and sprocket drive 3|.

Inward travel of the bucket-from left to right, as viewed in Fig. 1-is accomplished by a cable 32, which passes partly around the othersheave 29, thence upwardly through the pivot sleeve I! and over a frame-carried sheave 33 to the drum 33, to which the upper end of the cable is attached. The cables 25 and 32 are Wound upon the drum in opposite directions so that upon rotation of the drum in say a clockwise direction (as viewed in Fig. l) the cable 25 will be wound upon the drum while the cable 32 will be paid out therefrom, resulting in outward travel of the bucket along the boom, and when the drum rotation is reversed, the cable 32 will be rewound upon the drum and the cable 25 paid out. and the bucket will be drawn inwardly.

The bucket 24 is of the bottom-discharge type, and its discharge opening is normally closed by a pair of intergeared door structures 34 and 35 which are pivotally mounted as at 36 and 3'! respectively on the side wall of the bucket. As in my prior patents referred to above, the doors 34 and 35 are of the gravity-closing type, and are arranged to be opened by linkage comprising a link 38 extending from the door 34 to an arm 39 pivotally mounted at 40 on the front wall of the bucket, and a link 4| extending from the said arm 39 to the arm 42 of a bell crank lever 43 pivotally mounted at 44 on the trolley 23.

The second arm 45 of the bell crank is connected to a portion of the mechanism constituting the gist of the present invention, whereby the doors 34 and 35 may be opened and closed under all conditions, i. e. in any position of the bucket on the boom, and regardless of whether it be in motion or stationary thereon. This portion of the said mechanism comprises a rod 46 which slidably passes through a cylinder or guide structure 41 carried by the trolley 23, one end of which rod is connected by a link 48 to the bell crank arm 45. Within the guide structure 41 the rod 46 carries a collar 49 against which abuts one comprises a fluid-pressure cylinder 53 which may be mounted on the frame II and in which works a piston 54 having a piston-rod 55 the outer end of which carries a stirrup 56 in which is journalled a sheave 51 about which is trained a portion of the cable 32, as will be clear from Fig. 1.

The spring 50 is of such strength or is so preloaded as to normally maintain the parts in the positions shown in Fig. 1, and to transmit to the trolley 23, without yielding, the pull exerted on the rod 46 by the cable 32 when the drum 30 is being driven in a counter-clockwise direction. It results that so long as the piston 54 in the fluidpressure cylinder 53, and the sheave 51 actuated thereby, remain in the Fig. 1 positions, the trolley 23 and bucket 24 may be drawn inwardly on the boom as the cable 32 is wound upon the drum 30, without any relative movement between the rod 46 and the bucket 24 and without opening the bucket doors 34 and 35; and upon reversal of the winding drum 3!! the trolley and bucket may be drawn outwardly on the boom by the cable 25, likewise without opening the doors since the cable 32 is paid out from the drum at the same rate that cable 25 is wound thereon and there is thus no tension on cable 32 which would overcome the spring 50. However, if while the bucket is either stationary on the boom or is being traversed in either direction thereon, fluid pressure he admitted to the cylinder 53 whereby to move the piston 54 and sheave 51 toward the right, i. e. to substantially the Fig. 2 position, the additional tension thus placed upon the cable 32, plus the fact that the length of cable 25 between the drum 30 and trolley 23 and the tension thereon remains relatively fixed, will cause the spring 50 to yield and be compressed within the guide structure 41. The rod 46 will thus be moved toward the right, from the Fig. 1 to the Fig. 2 position, which motion through the linkage 48, 43, 4|, 33 and 38 will move the bucket doors 34 and 35 to their open (Fig. 2) positions. So long as pressure is maintained in the cylinder 53 to keep the sheave 51 in the Fig. 2 position, the doors will remain open, and during such time the bucket may remain stationary on the boom or be traversed in either direction thereon, as will be readily understood. Upon release of the pressure in cylinder 53 (with admission of pressure to the right hand end thereof if desired), the sheave 51 may return to its Fig. 1 position, permitting gravity and the spring 50 to restore the doors to closed position. Obviously, this may take place either before or after the entire contents of the bucket have been discharged, and regardless of whether the bucket be stationary or is travelling on the boom.

While the guide structure 47 which houses the compression spring 50 is illustrated in Figs. 1 and 2 as mounted on the trolley 23, obviously the invention is not dependent upon its disposition in this particular location. For instance, in some cases it may be desirable to mount the guide upon the bucket itself-for example, on the front of the bucketso that the full space above the bucket is available for the trolley. In such case the cable 32 may be directly connected to the arm 45 of the ball crank lever 43, with the other arm 42 of said lever rather than the cable 32 being influenced by the spring 50. Other similar variations will readily suggest themselves to those skilled in the art, but wherever the spring be located, its function will be to normally prevent relative movement between the bucket and the cable portion 32 except when movement of the sheave 51 overcomes the predetermined resistance of the spring.

The opening and closing of the bucket door is at all times under the control of the operator, who may fill the bucket with a batch of concrete and then discharge varying portions thereof ata plurality of spaced locations, while the mixer proceeds with the preparation of another batch. Patches or cavities which do not require a complete bucketful of concrete may thus be supplied with substantially just the right amount necessary for each of them, with the balance of the bucket Contacts being retained. in the bucket for discharge at other locations after traverse of the bucket on the boom and/or swinging of the latter to position the bucket at such locations. Thus it will be seen that the operator may start to discharge the bucket at any of its various positions on the boom, and regardless of whether the bucket is moving outwardly or inwardly or is stationary on the boom, may discharge whatever amount is necessary, stop the discharge while the bucket still retains concrete, and subsequently discharge the balance of the batch wherever and whenever desired.

In lieu of the fluid pressure device 53, 54, separate winding drums for the inward and outward bucket-traverse cables may be employed to attain the same results, and an example thereof is illustrated more or less diagrammatically in Fig. 3. Although it is perfectly feasible to mount such drums 653 and 6! upon a single shaft, they are here shown as mounted upon separate shafts 62 and 63 which are interconnected by gears 6d and 65 for rotation in opposite directions by means of a drive sprocket 65. The respective shafts are provided with appropriate clutches 6'! and 63 by means of which they may be connected at will to the drums 6B and 6!, and since the said clutches should never be engaged simultaneously, they may be conveniently controlled by a single lever 69 by means of which they may alternatively engaged, there of course being a neutral position (shown in Fig. 3) in which neither clutch is engaged. The drum 60 may receive the inward-traverse cable Hi and has a friction or other suitable brake H associated with it, while the drum 6!, which may accommodate the outward-traverse cable 72, has a similar brake i3 associated with it. The mechanism on the bucket and bucket trolley may be the same as shown in Figs. 1 and 2.

With this modified form of control, outward traverse of the bucket along the boom may be secured by moving the control lever 69 to engage clutch 68, thereby coupling shaft 63 to drum.

GI and causing the cable 72 to be wound thereon. At this time clutch B? of course is disengaged whereby drum B0 is free to rotate on shaft 62 and permit the inward-traverse cable 70 to be withdrawn therefrom, the brake ll preferably being applied with just suflicient force to prevent the drum from overrunning the cable. Conversely, by engaging clutch El and lightly applying brake E3, the bucket may be drawn inwardly on the boom.

So long as the braking action on the free drum is not in excess of that necessary to prevent merely the overrunning of such drum, the force transmitted by the traverse cable thereof will not be sufficient to overcome the resistance of spring 59, and therefore the bucket doors will not open. However, if during traverse in either direction the braking action on the unclutched drum be increased whereby to further retard or stop its rotation, motion ofits' cable will. likewise be retarded or stopped, with the result that the spring 50 will yield and the bucket doors will be opened, as described above. On the other hand, upon release of the excess braking action, gravity and the force of spring 59 will again close the doors. i

The doors may also be opened when the bucket is stationary on the boom by momentarily engaging either clutch while simultaneously fully braking the other drum. The engaged clutch of course should be disengaged almost instantly to prevent undue strain being placed upon the cables and other parts of the machine, and if it be desired to hold the doors open the second brake should be fully applied as the clutch is released, to prevent reverse rotation of its drum which would permit gravity and spring 50 to reolose the doors. When thus held open, closing of the doors may be effected by releasing either or both brakes.

It may be noted that in the bucket control systems disclosed in the above mentioned patents, and hereto-fore in general use, the traverse cables, as well as the tag line when used, are of fixed length in relation to the bucket. The present invention, on the other hand, provides means which in effect permit stretching or elongation of the traverse cable, and by such stretch or cable expansion the bucket doors may be opened to the extent desired, and subsequently closed through cable retraction. Such operation of the doors may be effected whenever the operator desires, at any location of the bucket on the boom, and regardless of whether the bucket is stationary or is traversing the boom in either direction.

What is claimed is:

1. In distributing apparatus for concrete mixers, comprising a boom, a bucket mounted thereon and provided with a discharge door, cable means for traversing the bucket along the boom, and means for alternatively tensioning different portions of said cable means to move the bucket in opposite directions on the boom: means for opening and closing said bucket door regardless of r the position, rate and direction of travel of the bucket on the boom, comprising connections between said door and one of said cable portions; a yieldable connection between such cable portion and the bucket, arranged to transmit the normal traversing force provided by said cable tensioning means to the bucket without yielding and without actuation of the bucket door; and means operable at will to place additional stress upon said cable means whereby to overcome said yieldable connection and cause movement of the door in one direction, said means also being operable at will to relieve such additional stress to cause movement of the door in the opposite direction.

2. In distributing apparatus for concrete mixers, comprising a boom, a bucket mounted thereon and provided with a discharge door, cable normal traversing force provided by said cable tensioning means to the bucket without yielding arm-mm andiwithout actuation of the bucketidoor; means operable atlwill toplace'variable:amounts of additionalstre'ss'rupo'n said? cable means. whereby. to overcome said yieldable" connection and cause varying degrees of movement of the door in one: direction, said'means also being operable at willto relieve such additional stress whereby to cause varyingidegrees' of movement of the door in the opposite direction 3. lnrd'istributing' apparatus for concrete mix- 'ers; comprising a boom,a'- bucket mounted'the're on and provided with a discharge-door which is movable" to its closedposition by gravity, cable means for traversing the bucket along the boom, and means foralternatively tensioning different portions of said cable'mean's to move the bucket in oppositev directions: on. the boom: means for openingand closingsaid bucket doorto various degrees, regardless'of the position, rate-or direction: of travel of the bucket on the boom at the time, comprising connections between said door andlon'e of said cable portions whereby the latter maymove the door toits'open position; a yieldable connection between such cable portion and the bucket, arranged to transmit the normal 4. In distributing apparatus for concrete mixers, comprisingaboom, and a bucket traversely mounted thereon; saidbucket'having a discharge door,xan' instrumentality 'for traversing the bucket on: the boom; and means for'actuating the same.:' connections between said instrumentality and the.

door'whereby the latter may be opened and closed incontrolled manner through relative movement between: the bucket and the instrumentality; means normally restraining said relative movement whereby traverseof the bucket by the instrumentality may be made without. actuation of 8 the" dooryandzmeans-oppOsed to said'restraining means, operable at will to causecontrolled-rela-- tive'movement between the-bucket and the-instrumentalit'y and thereby produce movement of the door to any desired position-from fully closedto fully open.

5'. In distributing apparatus for concrete mix-- ers, a boom; a bucket reciprocatably mounted thereon and having a discharge door and-means for operating thesame; a cable for traversing thebucket'on the boom, said cable havinga con'-- nection with the door operating means whereby the latter may be actuated through relative move-r ment between the cable and bucket; yieldable means for preventing, up to a predetermined limit, said relative movement between the bucket and" cable; means for'tensioning the cable below said limit to traverse the bucket on the boom without actuation. of: the door operating means; a movable. sheave? about which said cable is trained; and means operable at will to movesaid sheave and thusincrease th tension onsaid cable toabove said limit, whereby to cause the yieldable means to. yield and relative movement to occur between the bucket and cable with consequent actuation of the door operating means.

6. In distributing apparatus for concrete mixers, a boom; a bucket reciprocatably mounted thereon and having a'discharge door and means for operating the same; a cable for traversing the bucket on the boom, said cable having a connection with the door operating means whereby-the latter may be actuated through relative movement between the cable and bucket; resilient means for preventing; up to a predetermined limit, said relative movement between the bucket and .cable means 'for tensioning the cable below saidlimit to traverse the bucket on the. boom Without actuation of said door operating means;v a movable sheave about. which said cable is trained; and a fluid pressure device for moving. saidsheave'to increase the tension on the cable toabove said limit, whereby to cause said resilient means to yield and relative movement to occur between the bucket and cable with consequent actuation ofathe door operating means.

SAMUEL SHAFERgJRr

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