US2725220A

US2725220A - Self-sealing door

Info

Publication number: US2725220A
Application number: US348886A
Authority: US
Inventors: Hale Andrew; Robert K Perkins; Wallace H Woodrow
Original assignee: ACTNA STANDARD ENGINEERING COM
Current assignee: ACTNA STANDARD ENGINEERING COM; ACTNA-STANDARD ENGINEERING Co
Priority date: 1953-04-15
Filing date: 1953-04-15
Publication date: 1955-11-29
Anticipated expiration: 1972-11-29

Description

Nov. 29, 1955 A. HALE ET AL SELF-SEALING DOOR 4 Sheets-Sheet 1 Filed April 15, 1953 3 2 W S m R MW in m E W V M .H Mr N K .I. E w 4 $3 4 ARW a W 5 5 V. B

PEG. 3

Nov. 29, 1955 HALE ET AL 2,725,220

SELF-SEALING DOOR 4 Shets-Sheet 2 Filed April 15, 1953 FIG. 4

6 INVENTORS ANDREW HALE ROB K. PERKINS BY WAL E H. WOODROW ATTYS Nov. 29, 1955 A. HALE ET AL 2,725,220

SELF-SEALING DOOR 4 Sheets-Sheet 3 Filed April 15, 1953 United States PatentO SELF-SEALING noon Andrew Hale, Akron, Robert K. Perkins, Cuyahoga Falls, and Wallace H. Woodrow, Akron, Ohio, nssignors, by mesneassignments, to The Aetna-StandardEngineering Company, Pittsburgh, Pa., a corporation of Ohio Application April 15, 1953, Serial No. 348,886

16 Claims. (Cl. 259-48) This invention relates to an internal mixer and, more particularly, to an internal mixer of the kind that is provided with a discharge opening below the mixing chamber.

Mixers of this kind have commonly been provided with a sliding door for the discharge opening and, fastened to it, an associated door-actuating member, usually of the nature of an operating cylinder that surrounds and moves axially in relation to a fixed piston. Heretofore, the cylinder and the door attached to it havemoved as a unit, regardless of whether the movement of the two has been simple sliding movement in a horizontal direction or, as has sometimes been the case, a compound movement :that has been largely horizontal but which, during part of the horizontal stroke, has had a minor vertical component. Where such a compound movement has characterized the door closing operation, it has of course been necessary when introducing the vertical component to lift not'only the door itself but also the door-actuating cylinder to which it is fastened.

It is an object of the present invention to provide ,a sliding door that to a limited extent is capable of moving transversely of the door-actuating member. Thus where the latter takes the form of an operating cylinder, it may have movement solely in a horizontal direction while the door, in addition to having horizontal movement, may have a transverse movement that is largely independent of the horizontal movement of the cylinder. This is made possible by the fact that by the present invention mechanism is provided between the cylinder and the door which mechanism operates directly on the door to urge the door into and out of sealing engagement with the mixing chamber.

A further object of the invention is to provide better sealing engagement between the door and ,the mixing chamber, this in consequence of thefact-that as the door moves into sealing relation to the mixing chamber, it has a simple vertical movement rather than anoblique movement that has both horizontal and vertical components. One result of so relating the parts as ;to accomplish this object is less wear on the door and on'the mixing chamber, this because the door can be properly located below the mixing chamber immediately before the upward movement of the door is initiated. On dOOI'TOPClJiDg'IIIOVemBHT, the invention provides means for positively pulling the the door down out of engagement with the mixing chamber in response to movement of the door-actuating member, thus precluding or at least minimizingsticking, binding,-etc. along with the attendant wear .on the parts involved.

Other objects and advantages of the invention will be apparent from the description which follows and from the accompanying drawings, in which Figure l is an .end elevation of an internal mixer of a kind to which the .invention relates. Figure 2 is a vertical section Withparts in elevation, the section being taken parallel .to and between the end frames of the mixer. Figure-3 is an .elevation with parts in section showing'the' sliding door and top plan of the lower rackmember.

the operating cylinder as seen from lines 3-3-of Figures 2 and 5. Figure 4 is a longitudinal section with parts in elevation through the mixer on line 44 of Figure 2. Figure 5 is a vertical'section on line 55 of Figure 4.

Figure 6 is an end elevation as seen from line 6-6 of Figure 4. Figure 7 is a horizontal section on line 7--7 of Figure 6. Figure '8 is a view of the nature of an end elevation of the door as seen from line 8-8 ofFigure 4. Figure9 is a similar view of the opposite end of the door as seen from line 99 of Figure 4. Figure 10 is a vertical-section on line 10-10 of Figure 7.

Figure 11 is a side elevation of the upper rack member. Figure 12 is a bottom plan. Figure 13 is anend'elevation of the upper rack memberas seen from-the left in Figure 11. Figure 14 is an end elevation of the upper rack member as seen from the right in Figure 11. Figure 15 is a Figure 16 is a side elevation. Figure 17 is an end elevation of the lower rack member as seen from the left in Figure 16. Figure 18 is an end elevation of the lower rack member as seen from the right in Figure 16. In general, Figures 7 and 10 to 18 are on a relatively large scale, approximately half of .the full scale, while Figures 3 to 6, 8 and 9 are on a much smaller scale.

An internal mixer of the kind to which the invention relates, shown and designated 1 in each of Figures 1 and 2, includes such conventional elements as a hopper 2, a

stationary mixing chamber 3 (FigureZ), supporting structure therefor such as a bed 4, an end frame 5 at the drive end of the mixer, an end -frame6 at the'opposite end of the mixer, and, between the end frames, two spray sides 7, 7 (Figure 2) that serve as the side walls of the mixing chamber. The spray sides are so shaped as to form two conjugated cylindrical spaces 8, 8' that intersect and thus are in communication with each other in 1 thevicinity of the longitudinal axis of the mixer. Above them are the neck-forming portions 9, 9 of the mixing chamber, which portions provide open communication with hopper 2. Below

cylindrical spaces

8, 8, locating the mixing chamber on bed 4, are base portions 10, 10'.

Forming part of'base

portions

10,10 are two internal 7

ways

11, 11 which extend lengthwise of the mixing chamber, one on each of the two sides thereof. Overlying and coacting with them are the wings '12, 12 of a slidable cylinder 13 of a type that is commonly used in internal mixers of the kind described. The open space within the interior of cylinder 13 is indicated at 14 in Figures 4 and 5. Wear plates 13a seen in Figures 5 and 6 are fastened to and thus form part of the cylinder 13. Cylinder 13 is adapted to move into and out of the discharge opening of the mixing chamber, the lower end of which opening is indicated at 15 in Figure 2. Mounted on cylinder 13 and capable of moving with it is a sliding door 16, seen in outline in Figures '1 ,and 2 and in greater detail in Figures 3 to 6.

As hereinafter explained, door 16 is capable of moving to a limited extent ina direction transverse to the direction of movement of cylinder 13, this by virture of the presence of mechanism that acts directlyon door 16 to urge it into and out-.of sealing engagement with the mixing chamber.

At the .drive end of the -mixer,-cylinder 13 has .a cylinder head 17 provided with -a fluid connection 17a for admitting or discharging a pressure fluid'to or from the space 14 within the cylinder. These parts are seen to bestadvantage in Figures '1, 3 and 4. At the same end of the mixer, astationary-abutment 18 is mountedonend frame 5 asindicated in Figure 4 and, in end elevation, also in Figure 1. In the latter, abutment 18 .is seen .behind gears .19, 19' by whichpower is transmitted to rotors 2.0, 20' (Figure .2) from main drive shaft .21. Abutment 18 is in juxtaposition to the top portion of door 16, the relationship between them being shown most clearly in Figure 4.

Cylinder 13 surrounds and moves axially of a stationary piston and piston rod. The piston rod, designated 22 in the drawings, is fixedly mounted at its outer end in the supporting bracket 23 that appears in Figure 3. At its inner end it carries the stationary piston 24 shown in section in Figure 4. Between cylinder 13 and overlying door 16 is a rack assembly 25, seen in each of Figures 3 and 4, which consists of an upper rack member 26 rigidly fastened to the lower face of door 16 and a lower rack 27 rigidly fastened to the top of cylinder 13. Figures 12 to 18, inclusive, show the details of construction of

rack members

26 and 27.

For the present it is sufficient to notice that rack assembly 25 is located in door 16 between the usual water inlet passages 28. Cooling water is admitted by way of external connections 28a (Figure 7), passes through inlet passages 28 to the far end of door 16, travels repeatedly back and forth through other passages in door 16, and finally emerges from water outlet passage 29 near the top of door 16. Outlet passage 29 is provided with an external discharge connection 2% (Figures 4 and 6). At the end of door 16 opposite discharge connection 2%, outlet passage 29 is closed by the threaded plug 39 seen in Figure 4.

Above threaded plug 31) is a wear plug 31 of any suitably hard alloy. Wear plug 31 is rigidly fastened, as by peening over those portions that immediately adjoin it, to the end face of door 16. Contact with Wear plug 31 is by the stop member 32 of stationary abutment 13, which stop member is adjustably mounted in a bracket 33 that is rigidly fastened to a spacer 34 separating end frame from rotor end plate 35. The latter is one of two like rotor end plates. The one at the opposite end of the mixer, separated by a similar spacer from end frames 6, is designated 36. Door 16 is shown in Figure 4 in the position which it assumes when, toward the end of the door-closing stroke of cylinder 13, wear plug 31 makes contact with stop member 32 of stationary abutment 13.

At the opposite end of the mixer, the face of sliding door 16 fronting toward bracket 23 (Figure 3) is provided with a transversely extending wear plug 40 that is shown to best advantage in Figures 4 and 7. In contact with it is a spring-biased abutment member 41 that is formed as indicated in Figure 7. Integral with abutment member 41 is a stout cylindrical rod 42 that is threaded as at 43 near its outer end for cooperation with a nut 44 provided with a smooth-surfaced inwardly-directed sleeve portion 4411. Forming part of cylindrical rod 42 is a suitably shaped adjusting head 45. By manipulating the adjusting head, cylindrical rod 42 and abutment member 41 may be moved in or out relative to sleeve portion 44:; of nut 44. Surrounding cylindrical rod 42 is a heavy coil spring 46 which at its inner end seats against the near face 41a of abutment member 41. Spring 46 tends to urge abutment member 41 into constant contact with Wear plug 49.

At its outer end, spring 46 seats on an interiorly extending flange 47 forming part of a sleeve 48 which is provided with an exterior manipulating portion 48a and which is threaded as at 49 for reception in a correspondingly shaped threaded opening in a generally triangular mounting block 50 (Figures 7 and The manner in which block 50 is held in place appears from Figures 4, 7 and 10. Hold-down screws 51 that can be reached through access holes 52 serve to draw block 5t) down into contact with a mounting base 53 on cylinder 13. Underlying part of block 50 toward the outer end thereof is a saddle-shaped retainer 54, best seen in Figures 4 and 6. In part it covers the outer end of cylinder 13, extending over an arc of about 110 at the top portion thereof. Retainer 54 is rigidly fastened to cylinder head 55. It thus assists in holding block 50 in place. In consequence, block 511 and sleeve 48 in effect become part of cylinder 13.

As indicated in Figure 4, cylinder head 55 is generally similar to cylinder head 17 at the opposite end of the cylinder. it is provided with a fluid connection 55a for admitting and discharging pressure fluid at the end of cylinder 13 located outwardly of stationary piston 24. Cylinder head 55 carries a stuiiing box assembly 56 of conventional construction where it engages piston rod 22, thus preventing unnecessary loss of pressure within cylinder 13 by escape of the pressure fluid around the piston rod 22.

In the operation of the parts so far described, door 16 is moved into and out of position below the mixing chamber by the admission of pressure fluid into one end or the other of cylinder 13 and the withdrawal of pressure fluid from the opposite end.

If the parts are in the positions indicated in Figure 4, the admission of pressure fluid through fluid connection 535a in cylinder head 55 and the withdrawal of pressure fluid through connection 17a in cylinder head 17 will operate to move cylinder 13 to the right as seen in Figure 4. This movement of cylinder 13 brings about similar movement of door 16, which is connected to cylinder 13 through rack assembly 25. After the movement of cylinder 13 gets under Way, cylinder 13 and door 16 travel together as a unit, being held in the desired relationship to each other by rack assembly 25 and abutment 41, which is urged by spring 46 into contact with wear plug 40 on door 16. As cylinder 13 and door 16 continue to move to the right, the same relationship of parts is maintained until the limit of travel is reached, by which time cylinder head 17 is directly under rotor end plate 36. Discharge opening 1.5 is then fully open, permitting the contents of mixing chamber 3 to drop by gravity to an underlying conveyor (not shown).

Before charging mixing chamber 3 with a fresh batch of the materials to be mixed, pressure fluid is admitted to cylinder 13 by way of fluid connection 17a in cylinder head 17; simultaneously, pressure fluid is exhausted from cylinder 13 from the opposite side of stationary piston 24 through fluid connection in 550 in cylinder head 55. Cylinder 13 and door 16 thereupon move to the left, acting as a unit, until the end of door 16 in opposition to the drive end of the mixer makes contact with stationary abutment 18. At that time, all horizontal movement of door 16 comes to an end. By virtue of the construction and arrangement of the parts of rack assmbly 25, cylinder 13 continues to move in the same direction for a short distance beyond the point at which the horizontal movement of door 16 is terminated. Advantage is taken of this further movement of cylinder 13 to raise door 16 into sealing engagement with the mixing chamber: to this end, upper rack member 26 and lower rack member 27 are constructed and arranged as described below.

Referring first to lower rack member 27 (Figures 15 and 16), suitable openings 61 of which there are two series of five each along the two long sides of the rack member, are provided for fastening lower rack member 27 to the top of cylinder 13 by holddown screws or the like (not shown). Lower rack member 27 is in communication with a source of heavy lubricating oil under pressure through two oil lines 61 that pass through suitable openings in the bottom of block 51 (Figure 10). Accordingly, oil flows from oil lines 61 into two conduits 62 that are formed in and extend lengthwise of lower rack 27 inwardly of openings 60 (Figure 15). At the end of lower rack member 27 opposite that end from which oil is supplied by way of oil lines 61, conduits 62 are closed by plugs 63. Near the respective ends of the two conduits 62, chevron-shaped oil-release passages 64 communicate with conduits 62, there being one such oil-release passage at each end of each of the two conduits 62. Oil escapes through them to the top face of lower rack member. 27 near the two ends thereof.

Between the chevron-shapedoil-release passages at the opposite ends of lower rack member 27 are the shallow oil-release channels 65. Intheconstruction shown, there are two series of seventeen such channels, each directly over one of the two conduits 62. Oil-release channels 65 are fed by upwardly directed passages through which oil is supplied from the conduits 62. The two series of oil-release channels 65 serve to feed oil to two series of wedge-like steps 66, of which in the construction shown thereare sixteen over each of the two conduits 62. Thus the face of the lower rack member ,27 is lubricated at regular intervals in the stretches between the chevronshaped oil-releasepassages 64 at its two opposite ends.

Each of the wedge-like steps 66 is separated from the step which precedes it in the series;.i. e., the step to the right thereof as seen in Figure 16, by a short riser 67 which makes a right angle to the top face of the step. Each top face makes. an angle of to the horizontal. Between the two series of wedge-like steps 66, one series over each of the two conduits .62, is a relieved central area 68 which fails to exend all the way through lower rack member 27 to the bottom face .thereof but is formed after the fashion of a longitudinally extending central trough.

To the left of relieved area 6821s seen in Figure is an inclined surface 69, likewise making an angle of about 10 to the horizontal, which terminates as shown in Figures 15 and 16 ina transverse edge 70. The cutaway portion of lower rack member 27 overlying inclined surface 69 may, if desired, be regarded as extending all the way through lower rack member 27 to the bottom face thereof immediately to the left of transverse edge 70 as seen in Figure 15. Defining the left-hand limit of this cutaway area as seen in Figure 15 and bearing the same relation to the last of the wedge-like steps .66 as the risers 67 to the prior steps are two long risers 71, best seen in Figure 16. The upper edges of long risers 71 mark the inner ends of two long inclinedfaces 72, likewise making an angle of about 10 to the horizontal, which flank a longitudinally extending slot 73 extending inwardly from the end of lower rack member 27 As seen in Figure 15, slot'73 appears to be of uniform width; however, it is provided with undercut portions 74, best shown in Figure 17, which, taken together .with slot 73, provide a reversed T-shaped opening of the same Width as the transversely extending edge '70 on inclined surface 69. The undercut portions '74 have two longitudinally extending overhead surfaces 75 which, as seen from the left-hand end of lower rack member 27 (Figure 17), impart the T-shaped aspect to the opening therein. Overhead surfaces 75 incline to the horizontal at an angle of 10. Like

inclined surfaces

69 and 72, they are intended to coact with correspondnigly shaped surfaces on upper rack member 26.

At the opposite end of lower rack member 27, two long inclined surfaces 76 making an angle of 10 to the horizontal extend from the nearest of the -risers,67 to the extreme right-hand end oflower rack member 27 as seen in Figure 16. These surfaces are separated by a deep slot 77 which extends completely through lower rack member 27. At its left-hand end, slot 77 terminates in a long riser 78 paralleling long risers 71 at the opposite end of the rack member. To the left of long riser 78 as seen in Figure 15, the two surfaces 76 are connected by a bridging portion 76a. Bridging portion 76a also makes an angle of 10 to the horizontal. On opposite sides of slot 77 (Figure 18) undercut portions 79 flank the slot. The undercut portions 79 incline downwardly and inwardly as indicated in Figure 16 to provide overhead surfaces 80 which parallel the overlying inclined surfaces 76 and 76a. The undercut portions 79 flanking slot 77 give a reversed T-shaped appearance to the opening in the end of lower rack member 27 as seen in Figure 18. Undercut portions 79, and therefore overlying surfaces 80, terminate in a transverse edge 81 which lies almost directly below the f rst of the risers 67, considering them from right to left (Fig. 16).

2 Upper rack member 26 like lower rack member 27, is provided with two series of five openings, such openings being designated 86 in Figures 11 and 12, through which suitable fastening elementssuch as screws extend into contact with the lower face of door 16. Between the two ends of rack member 26 are two series of mutually similar wedge-like steps 87, fifteen in each series, which extend at an angle of 10 .to the horizontaloppositely to the wedge-like steps 66 in lower rack member 27. Whereas in the case of lower rack member 27 the risers 67 are to the right of the wedgelike steps 66 as seen in Figure 16,

in the case of upper rackmember 26 the risers 88 are to the left of the wedge like. steps 87 as seen in Figure 11. As indicated in Figure 12, upper rack member 26 has a relieved area 89 corresponding generally to the trough-like area 68 in lowerrack member 27. When the two rack members are in engagement with each other, wedge-like steps87 of upper rack member 26 are in contact with wedge-like steps 66 of lower rack member 27 more or less in the manner indicated in'Figure 3, wherein sliding door '16 is broken away to show'how the two rack members coact. The relationship there shown is what permits cylinder ;13 to continue to move to .the left after horizontal movement of sliding door 16 .has been brought to an end by abutment thereof againststop member 32 of stationary abutment 18.

Reference to Figure '14 will show that upper. rack member 26 has at its right-hand end a depending longitudinallyextending central web 90 that is seen in elevation in Figure 11. On opposite sides of central web 90 are two downwardly-extending inclined surfaces 91, likewise making an angle of 10 to the horizontal, that are adapted to coact with the inclined surfaces 76 of lower rack member 27. The surfaces 91 are connected inwardly of the end of central web 90 by a bridging surface 91a which coacts with the bridging surface 764: of lower rack member 27. The inner ends of surfaces 91. are delimited by two short risers 92 that are similar to risers 88, one for each of the surfaces 91. Flanking'central web 90 are two generally tetragonal flanking portions 93 (Figure 11). Each of the latter has an upper inclined surface 94 paralleling inclined surfaces-91. Taken with central web 90, flanking portions 93 present a T-shaped aspect when seen in elevation, as in Figure 14. At the opposite end of central web 90, a stop face 95 parallels risers 92, such stop coacting with stop face 78 of lower rack member 27.

At the opposite end of upper rack members 26, a similar longitudinally extending central web 96 depends from the lower face of the rack member. Flanking central web '96 are two pentagonal flanking portions 97, best seen in Figures 11 and 13. One of the five sides of the pentagon, seen from either side, ,is defined by an inclined lower surface 98 that is adapted to coact with inclined surface 69 of lower member rack 27. As in the latter, angle is 10 to the horizontal. Overlying pentagonal flanking members 97 are cutaway .areas 99, one of which is seen in Figure 11 The presence of cutawayfareas 99 provides each side with an upper surface 100 which inclines upwardly from its rear edge 101 to a more or less rounded recess 102 at its opposite end. Each of the recesses 102 terminates in the transverse edge 103 seen in Figures ll and 12. Below that portion of upper rack member 26 in which rounded recesses 102 are formed are two upwardly inclined surfaces 104 which in effect constitute step-like wedges similar to step-like wedges 87 and which, like them, coact with step-like wedges on lower rack member 27. Below upwardly inclined upper surfaces 100 and on the opposite sides of central web 96 the pentagonal flanking portions 97 are provided with upwardly inclined surfaces which are adapted to mate with the upwardly inclined surfaces 75 on lower rack member 27.

Upper and lower rack members 26 and 27-interfit in the sense that the reversed T-shaped elements depending from upper rack member 26 at the two opposite ends thereof are adapted to enter into slot 73 and the undercut portions 74 which flank slot 73 in lower rack member 27. Thus upper rack member 26 is in effect provided with elements of Tshaped appearance which serve to unite the two rack members by entering into correspondingly shaped recesses in lower rack member 27. Because of the fact that the coacting faces of the two rack members are inclined by the same amount (10), it becomes possible to have a limited amount of sliding movement of lower rack member 27 beneath upper rack member 26. This possibility is what permits lower rack member 27 and cylinder 13 to continue to move after termination of horizontal movement of upper rack member 26 and of sliding door 16 in door-closing direction.

in assembling door 16 to cylinder 13, the two are first brought into juxtaposition with each other with the coacting elements adjoining one another. This is best done by locating them in a manner such that upper rack member 26 will lie above but offset somewhat to the left of lower rack member 2'7 as seen in Figures 3, 11 and 16. Thereafter, with the T-shaped elements on upper rack member 26 in alignment with the T-shaped recesses in lower rack member 27, door 16 and upper rack member 26 are moved to the right, as seen in Figures 3, 11 and 16, thereby bringing the coacting surfaces into contact. Excessive movement is precluded by contact between door 16 and springbiased abutment member 41 (Figure 7) which, as previously explained, is mounted on cylinder 13.

With the coacting surfaces of the two rack members in contact, there can at most be only limited relative movement between them. Assuming that door 16 and cylinder 13 are in a position remote from stationary abutment 18 at the drive end of the mixer, spring-biased abutment 41 operates to push upper rack member 26 to the left as seen in Figure 3. This continues until the risers 88 adjoining wedge-like faces 87 on upper rack member 26 lodge against risers 67 adjoining wedge-like faces 66 on lower rack member 27. So long as

risers

67 and 88 are in contact, the two rack members and therefore sliding door 16 and cylinder 13 can move together in door-closing directron.

When, however, the horizontal movement of door 16 is terminated as a result of the fact that wear plug 31 has come into contact with stop member 32 of stationary abutment 18, it is still possible for lower rack member 27 and cylinder 13 to continue for a short distance in the same direction, this by virtue of the fact that all of the inclined surfaces of lower rack member 27 complement corresponding inclined surfaces of upper rack member 26. Continued horizontal movement of cylinder 13 and lower rack member 27 results in a wedging action the net effect of which is to urge upper rack member 26 upward. This upward movement of upper rack member 26, and therefore of door 16, follows immediately upon termination of horizontal movement of door 16, its movement being vertical or directly upward rather than at an angle. While such upward movement is of small proportions, being of the order of a few thousandths of an inch in an installation of the kind illustrated in Figures 1 and 2, it sufiices to force door 16 into tight sealing engagement with rotor end plates 35 and 36 (Figure 4).

Thus only door 16, that is, the part which forms the actual closure, is raised by the horizontal movement of cylinder 13. This is done'by providing means between cylinder 13 and door 16 which exert a lifting movement on door 16. When it is desired to open discharge opening 15, the movement of cylinder 13 is reversed, causing

inclined surfaces

75 and 30 on lower rack member 27 to pull down, respectively, on inclined surfaces 105 and 94 of the T-shaped elements at the two opposite ends of upper rack 26. Once lower rack member 27 has been set in motion; i. e., from left to right as seen in Figure 4, lower rack member 27 pulls upper rack member 26, and

therefore door 16, downward out of sealing engagement with mixing chamber 3, thus preventing sticking and gripping of door 16 at the ends and along the lower edges of the semi-cylindrical spaces 8, 8' in which rotors 2&1, 20' turn in the operation of the mixer.

These features and this arrangement of parts provide important advantages as compared with prior art constructions in which other means have been employed for giving a compound movement to the elements making up the closure. In prior art constructions, not merely the door but the underlying cylinder is moved upward into the final position. Such movement, instead of being vertically upward, is along an inclined path. As compared with such prior art constructions, the construction shown in the drawings and described in the foregoing specification provides a better seal and reduced wear. Where existing equipment is being rehabilitated, it is a relatively simple matter to introduce these features and advantages as part of the reconditioning operation, this by incorporating the above-described rack assembly between the cylinder and the overlying door.

It is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention.

We claim:

1. In an internal mixer of the type characterized by a stationary mixing chamber provided with a discharge opening below the mixing chamber; supporting structure for the mixing chamber below the discharge opening; ways on the supporting structure; a moveable member coacting with the ways on the supporting structure, said moveable member being reciprocable between an extended position removed from the mixing chamber and a retracted position in proximity to the mixing chamber; a moveable door for the opening in the mixing chamber, said door being non-rigidly mounted on the moveable member but being nevertheless reciprocable in response to reciprocation of the moveable member; and mechanism intervening between them providing independent movement of the door in a direction transverse to the direction of its responsive reciprocatory movement, said mechanism acting directly on the door itself to urge the door into and out of contact with the mixing chamber.

2. An internal mixer as in claim 1 in which the mechanism intervening between the door and the movable member includes a rack mounted on the door.

3. An internal mixer as in claim 2 in which the rack is characterized by wedge-like elements which face toward the moveable member.

4. An internal mixer as in claim 3 in which the moveable member carries wedge-like elements coacting with the wedge-like elements on the door.

5. An internal mixer as in claim 4 in which the coacting wedge-like elements on the movable member take the form of a rack.

6. In an internal mixer of the type characterized by a stationary mixing chamber provided with a discharge opening below the mixing chamber; supporting structure for the mixing chamber below the discharge opening; a door-actuating member coacting with the supporting structure, said door-actuating member being reciprocable into and out of a position in proximity to the opening in the mixing chamber; a moveable door for the opening in the mixing chamber, said door being non-rigidly mounted on the door-actuating member but being nevertheless reciprocable in response to reciprocation of the door-actuating member; mechanism intervening between the door-actuating member and the door providing independent movement of the door in a direction transverse to the direction of its responsive reciprocatory movement; an abutment carried by the door-actuating member; and, forming a part of said abutment, biasing means operating on the door.

7. An internal mixer as in claim 6 in which the abutment incorporates a stationary guide for the biasing means.

8. An internal mixer as in claim 7 in which the bias- 9 ing means take the form of a coil spring of a low degree of resilience.

9. An internal mixer as in claim 8 in which the spring operates on a plunger which in turn operates on the door.

10. In an internal mixer of the type characterized by a stationary mixing chamber provided with a discharge opening below the mixing chamber; supporting structure for the mixing chamber below the discharge opening; a door-actuating member coacting with the supporting structure, said door-actuating member being reciprocable into and out of a position in proximity to the opening in the mixing chamber; a moveable door for the opening in the mixing chamber, said door being non-rigidly mounted on the door-actuating member but being nevertheless reciprocable in response to reciprocation of the dooractuating member; mechanism intervening between the door-actuating member and the door providing independent movement of the door in a direction transverse to the direction of its responsive reciprocatory movement; a stop for the door; an abutment carried by the door-actuating member; and, operating on the door, biasing means urging the door away from said abutment and toward said stop.

11. An internal mixer as in claim 10 in which the stop for the door is mounted on the mixing chamber adjacent one end of the chamber.

12. An internal mixer as in claim 11 in which the stop for the door is located in alignment with the top of the door.

13. In an internal mixer, the subcombination comprising a movable door having a recessed portion on one side thereof; a movable cylinder for operating the door, said cylinder having a recessed mounting base engaged by the recessed portion of the door and, intervening between and interconnecting the cylinder and the door, a rack assembly consisting of a pair of opposed racks so constructed and arranged as to be capable of relative movement one of which is rigidly mounted on the cylinder and 10 the other of which is rigidly mounted on the door, said rack assembly fitting into opposing recesses in the recessed portion of the door and the mounting base on the cylinder.

14. A subcombination as in claim 13 in which the two racks are coupled together by means of a T-shaped tongue on one rack which has a sliding fit in a correspondingly shaped slot on the other rack.

15. A subcombination as in claim 14 in which there are two T-shaped tongues, one at each end of the rack, and a correspondingly shaped slot at each end of the cooperating rack.

16. In an internal mixer of the type characterized by a stationary mixing chamber provided with a discharge opening below the mixing chamber; supporting structure for the mixing chamber below the discharge opening; ways on the supporting structure; a moveable member coacting with the ways on the supporting structure, said moveable member being reciprocable between an extended position removed from the mixing chamber and a retracted position in proximity to the mixing chamber; a moveable door for the opening in the mixing chamber, said door being non-rigidly mounted on the moveable member but being nevertheless reciprocable in response to reciprocation of the moveable member; and mechanism intervening between them providing independent movement of the door in a direction transverse to the direction of its responsive reciprocatory movement, said mechanism acting directly on the door itself to urge the door into and out of contact with the mixing chamber, such mechanism including a pair of opposed racks coupled together by tongue-and-slot connections at the ends thereof.

Schnuck et al Oct. 20, 1942 Schnuck et a1. Oct. 28, 1952