US 2395571 A
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Description (OCR text may contain errors)
\ A. M MlLLAN CONCRETE MIXER Feb. 26, 1946.
Filed March 17, 1944 Patented Feb. 26, 1946 UNI TED STAT ES PATENT QF FICE.
GQNGBETE MIXER Andrew McMillan, Milwaukee; Wis assignor to Chain Belt Company, Milwaukee, Wis, a corporation of Wisconsin ApplicationMarch 17, 1944, Serial No..52.6, 931' 6 Claims; (Q1. 1 77311-)' The invention relates. to. concrete mixers. more particularly those equipped with. materialr-trans fer chutes; and has. for its. principal object; the provision of simple and effective; mechanism whereby the operator maybe. advised promptly upon the completion of the transfer of a batch ct material by the chute. Since the. invention has been-developed; primarily for use. in connectiorrv with the well known discharge chuteswhereby the batches of mixed concrete are transferred rom the mixing chamber at the conclusion. of the mixing'operation, icrpurposes of. the present disclosure itwill be described in; such connection, although those skilled in the art' will readily recognize that it isnot necessarily limited solely thereto.
In one typical form of concrete mixer in. wide use a power driven rotatable mixing'drum has a transfer chute associated'withits discharge opening, which. chute is movable. manually orsby power driven means between an operative and.- an ill0l erative position relative to. said drum opening. In its. operative position at least a portion of the chute lies. within. the drum. and inclines downwardly toward the discharge opening, whereby concrete mixture deposited in such portion by bucket -like". formations provided interiorly of the rum and gravitationally flowing down the chute may be directed through the dischar e opening tothe-exterior or the drum.
mmanyinstances the movements of the chute to. and from its operative position are under the control of some. form. of: automatic mechanism whereb the operations. of the variousinstrumcn .talities of the: machine, including: the said chute movements, are caused to take place. relative to one. another in an accurately timed. cycle-.. Such automatic control devices however, usuallypermit: of; the operator taking; instant manual control of- 17116201111116, if necessary.
Under normal automatically controlled. operation the control device is. usually set to hold. the chute in its. discharging position for atimesuineientv to insure complete. discharge of a batch from: the drum under the. most unfavorable con.- ditions apt to. be; encountered, as for example, when. working on downegrades, handling oversize. batches, etc; However... with such setting of the automatic control mechanism, time may be lost, when such unfavorable conditions; do not ob.- tain, sinceunder more; favorable conditions several; seconds may. elapse. after the batch is. completely discharged from the drum beforetheautomechanl'sm. moves. the chute to inoperative position. Rapid changing of the settings of the automatic control devices to take care of chan ing conditions of operation is not ordinarily feasible.
To avoid the loss of time just mentioned, the present invention provides simple and efiective meansv for. audibly orv visually advising. the operator in the event discharge. of the batch: is completed prior'to the expiration ofthe period determined by the automatic control setting, whereby he may. takemanual control of the: chute-to effect its movementv to non-discharge position. Obviously too, the invention. maybe. employed to advantage where some. or all of the variousi-unctions of the machine'are normally under manual control, at the volition of the operator.
Gne f-ormof the invention has been illustrated, mcre'crless diagrammatically, in the accompanying drawing forming a part of thiszspecificaticn, in which like reference characters designate like parts throughout the views, andin which Fig. I is a sectional-elevational view of the pertinent elements of a concrete mixer of the type. above.- mentioned, with theinventioh applied. thereto, the parts being illustrated in the positions. assumed whenthe discharge chute is in itsinoperative position; and
Fig; 2 is a similar view'showing; the positions of the parts when the chute is in its operative position:-
The mixer elements here shown comprise the rotatable mixing: drumlil having a discharge opening H in. one end. wall thereof, adjacent which Opening av dischargechute I2 is mounted by a transverse-rock-shaft 13 for swinging movements between; the positions illustrated. inFigs. 1 and 2 respectively. 'Theinterior of the drum it may be. provided. with conventional mixing blades and. pickup bucket formations, not shown but well known in the art. A fixed sub-chute. M is mounted by a member l5 of themachine framework... the major portion of which sub chute lies exteriorlyof the opening H, as will be clear from the drawing. The chute 12 carries a hinged. extension. ta-which in the operative positionsof the. parts serves. to bridge a gap betweenv the lowermost end of the chute l2 and the sub chute 14, as shown in Fig. 2.
The chute is movable between the two positions shown by anarm 26 carried by the. shaft hi, to which arm is'comlected a rod 2i. which carries a housing 22. A second rod 23.- slidably enters the said housing through its lower head 24, which second rodis provided with a flange or head 2.5.
A coiled compression spring 26 is interposed between. the heads :2! and 25 and tends-tomaintain the. rods 2%. and 23, and housing 22 in theliig. 1 positions. 'lhe rod 23 is connected to one. arm of a bell-crank lever 21- mounted onv a. member 23. of themachine irameand having s. o r. arm connected by a link 29 to, a power-drivenuactuating mechanism. of appropriate. conventional. type such for example. as that-disclosed in pri'o U, S. Patent No. 1,415,411 granted May 9, 1922 on an application filed by Samuel Sharer, Jr. This device may be under the manual control of the operator, or it may in turn be controlled by an automatic control mechanism, such for example, as
that disclosed in prior U. S. Patent No. 1,608,831 granted November 30, 1926 on an application filed by Charles F. Ball.
As is well known to those skilled in this art,
the power actuating mechanism of the said Sharer 2 by pulling upon the link 29, which motion is transmitted through the several elements 21, 23, 25, 26, 24, 22, 2| and 20 to the rock-shaft l3, which swings the chute into the drum. After an interval determined either by the operator, in the case of manual control, or by the control mechanism of the Ball patent, in the case of automatic control, the power actuating device pushes upon the link 29 to restore the parts to the Fig. 1 positions.
In-moving the chute into the drum the power actuating mechanism tends to position it substantially as indicated in broken lines in Fig. 2. However, with a batch of concrete in the drum being lifted by the discharge buckets thereof and droppedinto the chute, the weight and/or impact of the mixture will cause the chute to occupy substantially the full line position shown in said figure, This produces a compression of the spring 26 and a separation of the rods 2! and 23, as also indicated in said Figure 2. When thebatch has been discharged and there is no longer any concrete in the chute, the spring 26 will expand and lift the chute to the broken line position; and in accordance with this invention this movement of the parts as the discharge is completed is utilized to control an appropriate signal whereby the operator may be immediately notified of such fact.
One mode of accomplishing the result is shown diagrammatically in the drawing, wherein an electric switch 30 is arranged to be actuated by the relative movement between the rod 23 and the housing 22. This switch controls a circuit 3| which includes a suitable signal 32, such as a lamp, bell, horn, etc. So long as the spring 26 is expanded and the elements 22 and 23 are'in substantially the Fig. 1 relation, the switch 30 remains closed. When the parts 22 and 23 are in the Fig.2 positions as a result of the weight and/or impact of the concrete in the chute as above described, the switch 30 will be open and the signal 32 not energized, but when the spring 26 restores the elements 22 and 23 to the relative positions or Fig. l at the conclusion of discharge, the switch will be closed and the signal will indicate the completion of discharge to the operator.
In order that the signal 32 will not be actuated when the chute is out of the drum, 2. second switch 33, normally open, is included in the circuit 3|, being appropriately positioned to be closed by some part of the chute-moving linkage, as for example an arm of the bell-crank lever 21, as the chute reaches discharge position,
While one form of the invention has been illustrated and described it willlbe obvious that those skilled in'the art may vary the details of construction as well as the precise arrangement of parts without departing from the spirit of the invention, and therefore it is not wished to be limited to the above disclosure except as may be 'required by the claims.
What is claimed is:
1. In a concrete mixer having a. mixing receptacle and a material-transfer chute which is movable between an operative and an inoperative position relative to the receptaclei a signal; means responsive to the presence and absence of material in the chute to actuate the signal at the completion of a material transfer; and means for preventing actuation of the signal when the chute is in its inoperative position.
2. In a concrete mixer having a mixing receptacle, a material-transfer chute, and means for moving said chute between an operative and an inoperative position relative to the receptacle: an electric circuit including a signal; means for controlling said circuitin response to the presence and absence of material in the chute, whereby to actuate the signal at the completion of a material transfer; and means for rendering said circuit inoperative when the chute is in its inoperative position.
'3. In concrete mixing apparatus and the like, having a material-transfer chute mounted for movements to and from an operative position, and mean for so moving said chute: the combination of means comprising a yieldable connection between said chute and moving 'means, whereby, when the chute is in said operative position, relative movements may take place between it and the moving means in response to the presence and absence of material in the chute; a signal; and mean responsive to such relative movements between the chute and moving means for controlling said signal whereby to indicate the absence of material in the chute.
4. Apparatus according to claim 3, having means for preventing actuation of the signal when the chute is in its non-operative position.
5. In concrete mixing apparatus and the like, having a material-transfer chute mounted for movements to and from an operative position, and means for so moving said chute: a connection between the chute and moving means arranged to secure a predetermined relationship between the two whenever the chute is empty, and to yield upon deposit of material in the chute whereby relative movement may take place between the chute and moving means; a signal; and means controlled by said movements between the chute and moving means for actuating the signal to indicate: absence of material in the chute upon completion of the discharge I thereof.
6. In concrete mixing apparatus and the like, having a material-transfer chute mounted for movements to and from an operative position, and means for so moving said chute: resilient means arranged to transmit force from said moving means to the chute without yielding whereby to move the chute to said operative position, said resilient means being yieldable upon deposit of material in the chute whereby the latter may move slightly relative to the moving means; a signal; and means operable by the relative movemerits between the chute and moving means for controlling the signal whereby to indicate completion of the discharge of material so deposited in the chute.