US1899167A - Brake-control mechanism for concrete mixing and other machines - Google Patents

Description

Feb. 28, 1933. s SHAFER, JR 1,899,167

BRAKE CONTROL MECHANISM FOR CONCRETE MIXING AND OTHER MACHINES Filed Feb. 1, 1927 :s Sheets-Sheet .1

Feb. 28, 1933. s. SHAFER, JR

BRAKE CONTROL MECHANISM FOR CONCRETE MIXING AND OTHER MACHINES Filed Feb. 1, 1927 3 Sheets-Sheet 2 Feb; 28, 1933. 5. SHAFER, JR 1,899,157

BRAKE CONTROL MECHANISM FOR CONCRETE MIXING AND OTHER MACHINES Filed Feb. 1, 1927 3 Sheets-Sheet 3,

Patented Feb. 28,1933 1 rsm mzsnnmm orrmrnwauxnn wrsconsrinassrcnon ennu -3 m; n t

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v i o Application filed February 1,1921? Serial No. 165,171. 1 i p in In the operation of concrete mixing Illa- ,land 2 and with the dash'potth'ereof broken chines it is customarytofload therevolving drum-: in which concrete is mixedbymeans I i of a pivotedskip that rests upon the ground 1 i 5 to receive itsload .andis then elevated 'to' such position that the charge will slide into the interior of the mixingdrum; The movements of the skip are ordinarily controlled by cables that are 'connectedwith the skip'and pass to :710 winding, drums, which are driventhrough gearing connected with a suitable source'of descent of the skip is usually power. The 7 controlled by means of a brake that retards V the'unwinding'of thecables, this brake being manually controlled, "It 'sometimes happens that through inattention or inefficiency of the operator the skip is allowed :to descend with- -out being controlled by the brake, and this has resulted in the injury of workmen, im-

7 mediate damage to the-apparatus; andthe entanglementofthe cables, due to therapid rotation of the drums on which they are sup- 1ported',"which "latter is an almost inevitable resultof too rapid descent of the loaded'skip,

25 andmeans-trouble and delayin properly're-c storing the cables to positions upon thedrums and-perhaps serious injury to the machine if attempt bemade'to elevat'e theskipfbeiore g v 7 the cables have beenproperly replaced. i I

My invention has for its object to provide i'autoinatic means, for controlling the descent T of the skip in a machine such as described and for controllingthe movements of apiece of sme e sm y i ed-by e loading s a concrete inlx ng machine, and one embodi- ,Qment thereof is illustrated in the' accom'panying drawings and will be described in the specification tofollow, .i

it 40 q In th drawlngsFig, 1 isaiside view of a a v concrete -mixing machine to whichvmy inven- .tion-is app'1ie l 1 a Fig: 2isan end view ofthe same; i a r '-.Fig.;3 isan end @view of the brake contro mechanism drawn to a largersca'le than Figs.

for "manual control. 1

' mixing machine of well known construction,

in which A represents i. a rotatable drum wherein the concrete is mixed-,B the loading skip pivotall'y supported" on a shaft b mount,

edin 'the fra meworkG of the-machine; The inovementsof the 'skip,-fromitslower charge- 3'55 receiving position, represented in full lines,

to its elevated discharging position, indicated in dotted linesyare controlled by cables D whichfare wound'upon drumsld, supported on across shaft mounted in the upper part 0 ofth-e-framework C. A largeqwheel Ekis" supported onthe same shaft as that carrying the drums d, and to this is attached a cable Fthat extends to the winding drum G; The drum G is rotated to'wind the cable "F thereon andelevate the skip to .disch'argingxposition from a powershaft H, through suitable gearing. including a clutch 1,: controlled'by an operatinglever J, the lever-being'adapted L Associated web t winain (1mm 1G is a brake wheel or drum K' with which'enzages a brake 'bandL controlledibya lever M,which islikewise adapted for manualcon- I ,trol. The parts thus far. described-are of well known. construction 18nd, so far as my present invention is concernedythey may be I ofthe specific form shown orthey mayi difie'r therefrom quite widely inr-det'ails of constructio'n and in arrangement. 1

Th-eshaft b to whichtheskip is secured is represented as provided with a crank {arm 2, located on'the same side of themac-hine as is" the brake lever M? j Adash-pot- 3 con- J nected with the brakelever, as by a pivot45 5' The dash-pot; which may beof usual con-c structiomhasa piston '5 that connected by V 'apiston rod 6 with the crank arm 2, the piviota; connection of these parts being indicated v An air port 8 opens to the external atmosphere through the cylinder of the dash-pot on that side of the piston 3 that is toward the brake lever. A needle valve 9 is arranged to control the size of this port. It will thus be seen that there is interposed a dash-pot between a part that moves as the skip is raised and lowered and the brake lever. As the skip is raised to discharging position the crank arm 2 is moved in the direction of the arrow, Fig. 1, moving the piston 5 of the dash-pot downward or in a direction away from the brake lever, and as it so moves air is drawn into the cylinder of the dash-pot through the port 8. As the skip moves slowly as it is elevated from its loading position to that ofdischarge there will be abundant timefor the" cylinder of the dash-pot to fill with air, through the port 8, without perceptibly opposing the upward movement of the skip. After the skip reaches the position to discharge, the driving connection with the power shaft is broken, through the manipulation of the lever J that controls the clutch, and the skip may then be momentarily held in its elevated position, either by the usual spring 10, or manually by moving the handle M'tO apply the brake. But a light application of the brake is required for this purpose as the center of gravity of the skip is so little to one side of the vertical plane that includes the pivot 6. Instead of providing for a short rest or dwell ofthe skip in its raised discharging position the apparatus may be so designed that the skip will begin'its downward movement as soon as the driving .con-

nection with the power shaft is broken through the manipulation of the clutch. As the skip moves downwardly the shaft 1; is rotated and the piston 5 is moved upwardly within the cylinder of the dash-pot compress- 7 ing the body of air between the piston and the upperend of the cylinder. The pressure thus created, acts upon the cylinder, and through its pivotal connection 4 with the lever M, upon such'lever, to set the brake, and the more rapid the descending movement of the skip the greater the force with which the brake is applied. If the portion of the cylfinder to therear of the piston 5 were closed air tight, it is apparent that the brake would very soon be so tightly set as to hold the skip suspended against further downward movement; but as the port 8 allows for a leakage of the air within the cylinder, the pressure therein is gradually reduced, with a corresponding reduction of 'thepressure of the brake upon the drum K and thusthe-brake is kept applied with just enough pressureto allow the skip to descend safely.

The relations of the Various parts are such that the leakage of air through the 'port 8 will be just sufficient to maintain an air pressure within the dash-pot 1 that will set the braketo such a degree as will allow the skip vated; the pivoted part returning by to descend at the desired speed. If it should be found that the descent is too slow the needle valve 9 will be adjusted to enlarge the port; while on the other hand if the descent be too rapid the size of the port will be reduced by such valve.

I have described means by which the descent of the loading skip is automatically controlled and this is done through the application of a brake associated with the winding drum of the cable that moves the skip. The lever with which the dash-pot is connected is, as has been stated, a lever capable of manualcontrol, and this permits the operator of the apparatus to govern the descent of the skip quite'irrespective ofthe automatic apparatus that has been described,

allowing im either to set the brake, at any point in the, descent of the skip, with a force suflicient to immediately arrest the movement thereof, or to accelerate the. descent of the skipbeyond thespeed contemplated by'the operation ofthe automatic apparatus.

WhileI have described my invent-ion applied to aconcrete mixing machine it is not,

operated lever for controlling the brake, of.

connections between the moving part and the brakev through which the latter is automatically controlled by the movements of the former and inaccordance with its speed, the brakebeing manually operable irrespecfive of the automatic operating means.

*2. The combination with a moving pivoted part'of an apparatus, a brake for controlling its movements and a imanually operated brake lever, V pivotedpart and the brake leverthrough part moves.

3. The combination with a pivoted part of an apparatus, a cable through which it is elegravity, a brake-for controlling the return movements of the said part and a manually operated brake lever, of an arm movable with the pivoted part and a connection between the said arm and the brake lever including a dash-pot.

4. The combination with a pivoted movable part of an apparatus, cables by which it is raised, power-driven winding mechanism for the: cables, a brake'by which the return or lowering movements of the said movable part are controlled and a manuall operated hand lever for the brake, of a era-n arm connected so'as to move with the said movable part and connections between the said crank of connections'between the said which the brake is operated as the pivoted V media? arm and the hrakelever inc luding a dash-pot.

5. The combination witha pivoted. movable part of an apparatus, cables by which it is moved, power-driven winding mechanism; for the cables, a drum" by which the returnor I lowering movements of the movable part-are controlled, and a manually operated hand lever for the brake, of a crankarm movable with the said movable part, a dash-pot having pivotal connection with thebrakelever; and a. rod carrying the pistonof the dash-pot having pivotal connection with the crank arm, the restrictedair port of thev dash-pot being in that end thereof toward the brake 1 lever. V

SAMUEL'NSHIAFER, Y r i

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