US2454940A

US2454940A - Seal for chutes of concrete mixers

Info

Publication number: US2454940A
Application number: US686633A
Authority: US
Inventors: Harry C Peters
Original assignee: TL Smith Co
Current assignee: TL Smith Co
Priority date: 1946-07-27
Filing date: 1946-07-27
Publication date: 1948-11-30
Anticipated expiration: 1965-11-30

Description

Nov. 30, 1948. H. c. PETERS 2,454,940

SEAL FOR CHUTES OF CONCRETE M IXERS Filed July 27, 1946 a'sneets-sneei 1 .lllum il Nov. 30, 1948, v H. c. PETERS 2,454,940

I SEAL FOR CHUTES OF CONCRETE MIXERS Filed July 27, 1946 2 Sheeis-Sheet 2 HHHIHI' QJIIFI,

Patented Nov. 30, 1948 UNITED" STATES 8.:Claimsr. (Cl. 259-161) E This inventionrelates to concrete mixers-and refers particularly toa: combination 1 feed chute and closure for-truok type concretemixers: V

In truck-mixers especially those of the high discharge-type, the-drum is loaded and-discharged. throughitselevated' open end at the rearof the truck. To enable rapid charging of the drum, asubstantially funnel-like feed chute is provided todirect the-aggregates through the mouth of the drum provided by its open rear end. Discharging ofthe drum contents is effected by reversingthe direction of rotation of the drum whereupon the spirally arranged mixing blades in'thedrum convey the concrete rearwardlyto spillkacross the-lower edge of its open end into anappropriate discharge chute.

Inasmuch as-it is preferable to have the drum closed ascompletelyas possible during transit, acover. is generally provided for the top of the funnel-like feed chute and the space between its discharge end and the edge of'the drum-is closed by an annular wall carried bythe feed chute-and engaging the edge of the drum.

This annular wal-lconsists of a central'nonrotatable part fixed to the feed chute and an outer rotatable part adapted to turnwith the drum. A- free running bearing is, therefore, provided between the central non-rotatable and outer rotatable parts of the annular wall. The provision of such-a bearing is a relatively simple matter, but. considerable difficulty has beentexperienced in the: past in' keeping it free from dirt and grout.

Many differenttypes of seals have: been proposed; in g the past to preclude; theentry of grout 'andioreignxmatter into the bearing frominside.

thezzdrum; but forone reason oranother all past expedients: directed to' this purposev havenbeen:

inadequate.

It is, therefore, the chief object of this invention to provide, a; free; running seal between the. central non-rotatable and the outer rotatable partsof the drum closure in a truck type concretemixer whichwill remain effectiveto pre-- cludethe passage of-grout and foreign matter.

intothebearing between the central, non-rotatableand the outer annular part, notwithstanding theexcessive, wear to which equipment f th type issubjected.

Another object of this: invention is'to provide.

ausealfor the purpose described, whichv is simplein. construction and so designed and constructed: thatthe efiectiveness of thesea-l is not, dependout upon the degree of pressure of the rotating;

elements against the drum opening.

Another object of .this invention is to provide a seal of the character described which will re-, main effective for'the life of the equipment by virtueof the fact that wear which takes place therein-merely improves the lit oi-the parts:

2. Withthe above and other objects in view which will appear as the description proceeds; this invention residesin thenovel construction, combination and'a-rrangement of parts substantiallyas hereinafter described andmore particularly;

defined bythe appendedclaims; it being understood that such changes in theprecise embodiment of the hereindisclosedinvention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete exampleof the physical embodiment of the invention constructed-according to the'best mode so far devised for-the practical application of the principles thereof, and in which:

Figure 1 is a View in side elevation withparts broken" awayand in-section illustrating-the rearend portion of a-truck type concrete mixer embodying t'his invention;

Figure 2"is a detailsectional view-through the seal and bearing betweenthe rotatable andnerrrotatable parts ofthe closure;

Figure3-is a-rear view of the complete structureshown in Figure 1;

Figure 4 is a fragmentary detail view illustratinga portion of one of the elements of the seal between the rotatable and non-rotatable closure parts;

Figure 5 is a cross sectional view through Figure 4 onthe plane of the line 5+5; and

Figure-6 is 'anexploded perspective crosssec tional View through the elements which coact'tog;

form the free-running seal.

Referring now more; particularly to the accompanying drawings; inwhich like numerals indicate likeparts, the-numeral 5' designa-tes. the

rotatable mixing drum of a truck type concrete mixer-Whichasiscustomary-in the high discharge mixers now ini eneral use, revolves about" The elevated rear end of the an inclined axis-.- drum -is open and; serves as a common charging anddischa-rgingmouth for, the drum. A drip ring 6- fixedthereto provides a solid finishmachined edge f or-the mouth of the drum.

Inasmuch as the invention is' not'con'cerned" with the -ma-nner in' which the-drum is mounted and driven thesefeatu-resare not illustrated. It is commonknowledgeto those-skilled in this art thatthecOn-tents of the drum are-discharged by r the action of the mixing blades (not shown) upon reverse rotation of the drum, whereby the concrete contained-therein is advanced to and;-

spi-lledout of the mouth of the drum;

Charging otthe drum isefiected through afunnel-li-ke hopperor feed chute- I pivotally mounted from the frame 8 of the supporting structure by means of arms 9.

chute-as at IO and their-upper inner ends are The outer ends n the arms 9. are pivotall "connected; to the feed:

charging position, shown in Figure 1, and an elevated discharging position by means of mechanism (not shown) acting through a connecting rod I2. The manner in which the feed chute is mounted and swung to and from its charging position is more particularly described in the patent to R. J. Barnes, No. 2,374,912.

The open top of the feed chute is adapted to be closed by a hinged cover I3 so that when the feed chute is in its charging position and the cover I3 is down, it serves to close the central portion of the mouth of the drum. The annular space between the discharge end of the feed chute and the edge of the drum is closed by an annular wall structure consisting of a non-rotatable annular plate I4 fixed to the feed chute and a rotatable annular plate or ring I5 mounted to revolve about the non-rotatable plate by means of a free running bearing structure indicated generally by the numeral I6. feed chute is in its closed charging position, the rotatable annular ring-like part I5 bears against the drip ring 6 to turn with the drum.

The bearing structure I6 by which the nonrotatable and rotatable parts I4 and I5 are connected for free relative rotation comprises a ring member I! bolted to the peripheral portion of the non-rotatable part I4 and a ring member I8 bolted to the inner peripheral portion of the rotatable part I5. The rings I1 and I8 have complementary flanges formed with mutually engaging right angularly disposed surfaces I 9 and 20. The latter cooperates with a retaining ring or flange 2| fixed to the rotatabe ring I8 to embrace a flange of the non-rotatable ring I I and thus hold said ring members together. Lubricant is fed to the bearing surfaces I9 and/or through one or more grease fittings 22 and appropriate passages.

While the mutually engaging bearing surfaces I9 and 20 provide an excellent bearing for the rotatable closure part I5 and assures its freedom to turn with the drum, these bearing surfaces would soon be ruined by the abrasive action of grout from inside the mixing drum unless the grout is effectually excluded from the bearing. The provision of a seal which will satisfactorily guard against the passage of grout and other foreign matter from inside the drum to the free running bearing is the chief purpose of this invention.

Thus the rotatable ring member I8 and an inner ring member or flange 23 bolted to the nonrotatable ring member II have adjacent

conical surfaces

24 and 25 respectively. These conical surfaces have their large diameter ends in juxtaposition and hence define an annular V-shaped groove opening radially inward to an annular lubricant reservoir 25'.

The reservoir 25 is formed conjointly by the ring members I8 and 23, and is of a size to receive an expanding split spring ring 26, the outer peripheral portion of which has a cross sectional shape corresponding to that of the V-shaped groove. Thus the expanding split spring ring has.

conical surfaces 21 to engage the

conical surface

24 and 25 with a snug surface-to-surface engagement, such engagement being maintained by the inherent resilience of the spring ring 26.; The lubricant reservoir 25' is adapted to be;

and .t e s m mb r i nd ?3 a b kept1uh.-;

Thus when the V and the inside of the drum, the passage of grout and foreign matter from inside the drum to the bearing is effectually precluded. The opening 3| between the ends of the expanding split spring ring is ordinarily so slight that there is little danger for grout to pass through it. 7

Positive assurance against even this slight leakage is obtained by a bridgingpiece 32 slidably received in slots 33 in the ends of the spring ring as shown in Figures 4 and 5. This bridging piece is, of course, shaped to have its side edges lie flush with the conical surfaces of the expanding split spring ring.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent that this invention provides a practical wholly satisfactory free running seal between the non-rotatable and rotatable parts of the closure or door for the mouth of a truck type concrete mixer and that the incorporation of the seal of this invention involves no radical change from a design found to be commercially acceptable.

What I claim as my invention is:

1. A closure for the mouth of a rotatable concrete mixing drum, including a non-rotatable part covering the central portion of the mouth of the drum, an annular rotatable part surrounding the non-rotatable part and engageable with the edge of the drum, and a bearing between said parts permitting free rotation of the rotatable part relative to the non-rotatable part, characterized by the provision of: a seal located between the bearing and the inside of the drum to prevent the passage of grout and liquid to the bearing from inside the drum, comprising adjacent annular surfaces on the rotatable and non-rotatable parts shaped to form an annular groove having diverging sides and openin radially inwardly; and an expanding spring ring in said groove maintained in contact with the diverging sides thereof by its own inherent resilience.

2. A closure for the mouth of a rotatable concrete mixing drum comprising: an inner nonrotatable and an outer rotatable part, said parts conjointly forming the closure for the mouth of the drum; means connected with the non-rotatable inner part for moving the closure to and from a closed position at which its outer rotatable part engages the edge of the drum to rotate therenon-rotatable part; adjacent annular members on said-parts located between said bearing and the inside of the drum, said members having annular surfaces coacting to form an annular groove; and a spring ring seated in said groove and maintained in snug engagement with the walls thereof by the inherent resilience of the spring ring.

3. A closure for the mouth of a rotatable concrete mixing drum of the type charged and dis-v charged through the same mouth and wherein" charging is effected through a feed chute mounted adjacent to the mouth of the drum for swinging to and from a position projecting into the central part of the mouth so that said feed chute covers the central part of the mouth of the drum when in its charging position, and wherein the annular space between the feed chute and the edge of the drum is closed conjointly by a nonrotatable part encircling and carried by the feed chute and a rotatable part rotatably joined with and encircling said non-rotatable part and engaging the edge of the drum to turn therewith, characterized by the provision of: a seal for the joint between the non-rotatable and rotatable parts comprising, annular members on said parts disposed between said joint and the inside of the drum and having adjacent conical surfaces coacting to form an annular groove with diverging sides, and a spring ring received in said groove and by its inherent resiliency maintaining snug engagement with the walls thereof.

4. In a concrete mixer: a rotatable mixing drum having an open end providing a mouth through which the drum is charged and discharged; a combination feed chute and closure for the mouth of the drum including a funnellike feed chute, a non-rotatable annular wall encircling and fixed to the discharge end of the feed chute, and an annular rotatable part rotatably joined with said wall and engageable with the edge of the drum to turn therewith; annular members on said rotatable part and the nonrotatable wall disposed intermediate the joint therebetween and the inside of the drum, said members having adjacent annular surfaces cooperating to define an annular groove; a spring ring seated in said groove and urged into snug engagement with the surfaces thereof to form a free running seal between said annular rotatable part and said wall; and means for moving said combined feed chute and closure to and from a closed position at which its annular rotatable part engages the drum to turn therewith.

5. In a concrete mixer having a rotatable mixing drum adapted to be charged and discharged through an open end thereof, a combination feed chute and closure for said open end of the drum, including a funnel-like feed chute, a non-rotatable annular wall encircling and fixed to the discharge end of the feed chute, and an annular rotatable part rotatably joined with said wall and engageable with the edge of the drum to turn therewith: a free running seal between said annular rotatable part and said non-rotatable wall, comprising cooperating annular members on said wall and the rotatable part having adjacent conical surfaces thereon with the large diameter ends of said surfaces in juxtaposition and radially outermost so that said conical surfaces conjointly form a radially inwardly opening V-s-haped groove; and an expanding spring ringseated in said groove, said ring having its outer peripheral portion V-shaped to fit the walls of the roove with a surface-to-surface contact and be maintained in snug engagement therewith by the inherent resilience of the spring ring.

6. In a concrete mixer having a rotatable mixing drum adapted to be charged and discharged through an open end thereof, a combination feed chute and closure for said open end of the drum, including a funnel-like feed chute, a nonrotatable annular wall encircling and fixed to the discharge end of the feed chute, and an annular rotatable part rotatably joined with said wall and engageable with the edge of the drum to turn therewith: a free running seal between said annular rotatable part and said non-rotatable wall, comprising, a stationary metal ring fixed to the non-rotatable annular wall, said stationary ring having a smooth finished annular surface; a rotatable metal ring fixed to the annular rotatable part, said rotatable ring having a smooth finished annular surface; said rings being coaxial and adjacent to each other and being interposed between said joint and the inside of the drum with their smooth finished annular surfaces in juxtaposition; a metal sealing ring between said smooth finished annular surfaces; and means for resiliently maintaining the sealing ring in snug engagement with said smooth finished annular surfaces, said sealing ring being free to turn with the rotatable ring or stand still with the stationary ring.

7. A closure structure of the character described comprising: a central non-rotatable part; an annular rotatable part; a joint between said parts providing for free rotation of the rotatable part relative to the non-rotatable part; means on said parts lying between said joint and the inside of the drum conjointly forming an annular substantially V-shaped groove opening radially inwardly; a metal spring ring seated in said groove, said ring having its outer circumferential portion V-shaped in cross-section corresponding to the angle between the walls defining the V-shaped groove so as to have snug surfaceto-surfa-ce engagement therewith; means on the non-rotatable and rotatable parts jointly defining an annular lubricant reservoir opening to the V-shaped groove, and embracing the radially inner portion of the spring ring; and means for introducing lubricant into said reservoir.

8. A closure structure of the character described comprising: a central non-rotatable part; an annular rotatable part; a joint between said parts providing for free rotation of the rotatable part relative to the non-rotatable part; means on said parts lying between said joint and the inside of the drum conjointly forming an annular substantially V-shaped groove opening radially inwardly; an expanding metal spring ring seated in said groove, said ring having its outer circumferential portion V-shaped in cross-section corresponding to the angle between the walls defining the V-shaped groove so as to have snug surface-to-surface engagement therewith; means on the non-rotatable and rotatable parts jointly defining an annular lubricant reservoir in which the radially inner portion of the spring ring is located; means for introducing lubricant into said reservoir; said spring ring being split and its adjacent ends having aligned slots in the outer portions of their V-shaped cross-section; and a bridging piece slidably received in said slots and extending across the space between the ends of the ring.

HARRY C. PETERS.

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

UNITED STATES PATENTS Number Name Date 2,265,751 Ball Dec. 9, 1941 2,265,752 Ball Dec. 9, 1941 2,267,801 Peters et a1 Dec. 30, 1941 2,374,912 Barnes May 1, 1945