US3334822A

US3334822A - Mulling machine

Info

Publication number: US3334822A
Application number: US328904A
Authority: US
Inventors: Robert L Mcilvaine
Original assignee: National Engineering Co
Current assignee: National Engineering Co
Priority date: 1963-12-09
Filing date: 1963-12-09
Publication date: 1967-08-08
Anticipated expiration: 1984-08-08
Also published as: GB1066952A; DE1432036A1; SE301364B; CH417288A

Description

Aug. 8, 1967 Filed Dec. 9, 1963 FIG! R. L. M ILVAINE MULLING MACHINE 4 Sheets-Sheet l I INVENTOR ROBERT L. MCILVAINE Aug. 8, 1967 Filed Dec. 9, 1963 R. L. M ILVAINE MULLING MACHINE 4 Sheets-Sheet 2 INVENTOR. ROBERT L. MclLvAlN BY/VAQWL/ w ATTORNEYS Aug. 8, 1967 R. L. MCILVAINE MULLING MACHINE 4 Sheets-Sheet 3 Filed Dec. 9, 1963 INVENTOR. ROBERT L. MclLVAINE ATTORNEYS 1967 R. L. MCILVAINE 3,334,822

MULLING MACHINE Filed Dec. 9, 1963 4 Sheets-Sheet 4 INVENTOR.

ROBERT L. MCILVAINE 8112M ATTORNEYS United States Patent Ofiiee 3,334,822 Patented Aug. 8, 1967 3,334,822 MULLING MACHINE Robert L. Mcllvaine, Winnetka, Ill., assignor, by mesne assignments, to National Engineering Company, Chicago, [1]., a corporation of Delaware Filed Dec. 9, 1963, Ser. No. 328,904 14 Claims. (Cl. 241124) The present invention relates to mulling machines and more particularly to a new and improved muller having novel means for supporting the mulling wheels.

One of the problems associated with mulling machines generally is that of obtaining the proper mulling pressure between the muller wheels and the material which is being mulled. Should the pressure become too great, the muller wheels will tend to plow through the material, lessening the kneading effect which is imparted by the rolling pressure of the muller wheels; while if there is not enough mulling pressure, the kneading efiect will also be reduced, large lumps and agglomerates which are objectionable will be present in the material.

Accordingly, it is an object of the present invention to provide a new and improved mulling machine for mixing and pulverizing materials in which novel means are provided for supporting and controlling the mulling pressure of the mulling wheels.

Another object of the present invention is the provision of a new and improved mulling machine in which a pair of mulling wheels are independently supported on opposite sides of a rotating cross-head and are independently biased to provide the desired range of mulling pressure.

More specifically, it is another object of the present invention to provide a muller of the type described having a new and improved adjustable biasing means for urging the muller wheels downwardly toward the base of the muller to obtain the desired mulling pressure.

Yet another object of the present invention is the provision of a muller of the type described wherein new and improved adjustable biasing means are provided for urging the muller wheels upwardly away from the base of the muller to provide for mulling pressures less than that obtained by the free weight of the muller wheel assemblies alone.

Still another object of the present invention is the provision of a muller having new and improved means for adjustably biasing the muller wheels both toward and away from the base of the muller in order to obtain mulling pressures in a range both greater than and less than that obtained by the free weight of the mulling wheel assemblies alone.

Yet still another object of the present invention is to provide a new and improved muller having a pair of intercommunicating material reserving cribs each including a rotary cross-head therein having novel means for supporting and controlling the mulling pressure of the mulling wheels and means for driving these cross-heads in selected synchronous relation with one another.

Briefly, the foregoing and other objects and advantages of the present invention are accomplished by the provision of a new and improved mulling machine including a material receiving crib having a base plate and a rotating cross-head assembly therein. A pair of independently supported mulling wheels are mounted on opposite sides of the cross-head assembly with each wheel being rotatably mounted on a horizontally disposed, outwardly extending axle. Each axle is carried by a support member which is pivotally mounted on the cross-head assembly to rotate about a horizontal pivot axis and each support member is provided with an upstanding actuating arm extending away from the axle carried thereby. In order to obtain the desired mulling pressure between the mulling wheels and the material in the crib, a pair of independent biasing means are provided, each being connected to exert a force on one of the actuating arms in a direction urging the wheels downwardly toward the base plate of the crib. The biasing means are adjustable in order to vary the mulling pressure on the material and stop means are provided for limiting the downward movement of the mulling wheels toward the base plate.

In one embodiment illustrated in the drawings, the muller comprises a pair of intercommunicating material receiving cribs, each having a rotating cross-head assembly as described and means are provided for driving. the cross-heads in selected syncronous relation with one another.

In another embodiment of the invention, there are provided a pair of second independent biasing means, each being connected to one of the actuating arms to exert a force in a direction urging the mulling wheels upwardly away from the base plate of the crib. In this arrangement, the first and second biasing means connected to each actuating arm are opposing one another and make it possible to obtain mulling wheel pressures in a range including values both greater and less than the pressure obtained by the free weight of the mulling wheel assemblies alone.

For a better understanding of the present invention reference should be had to the following detailed descrip-' tion taken in conjunction with the drawings, in which:

FIG. 1 is a cross-sectional elevational view of one embodiment of a new and improved mulling machine employing a pair of intercommunicating material receiving cribs and constructed in accordance with the features of the present invention; I

FIG. 2 is a top plan view of the mulling machine of FIG. 1;

FIG. 3 is a cross-sectional elevational view of another embodiment of a new and improved mulling machine constructed in accordance with the features of the present invention; and

FIG. 4 is a top plan view of the mulling machine of FIG. 3.

Referring now more specifically to the embodiment of FIGS. 1 and 2 of the drawings, there is illustrated a new and improved mulling machine characterized by the features of the present invention and indicated generally by the reference numeral 10. The machine 10 is of the multiple stage type which is generally described in United States Patent No. 2,943,801, assigned to the same assignee as the present invention; however, the present invention is also applicable to mulling machines of the single stage type.

The machine 10 comprises a pair of side by side

material receiving cribs

12 and 14 which are in communication with each other and have a common base plate 16. Material to be mixed and pulverized is first introduced into the crib 12 and is mixed and pulverized therein and transferred into the crib 14 for further mixing and pulverizing and eventually is discharged from the machine through the discharge doors 18 and discharge chute 20 as is more completely described in the previously men tioned US. Patent No. 2,943,801. The crib 12 is provided with an upstanding side wall 12a forming a portion of a cylinder and is joined with a similar upstanding side wall 14a of the crib 14. The side walls 12a and 14a of the cribs are provided with

replaceable wear plates

12b and 14b respectively and the common bottom or base plate 16 is provided with a replaceable wear plate 16a. The machine is provided with legs 22 which support the base plate and cribs from a floor surface 24 or other structure.

Within the crib 12 there is provided a rotating crosshead assembly 26 which is rotatable about a centrally located vertical axis 28 in the direction shown by the arrow 30 (FIG. 2) and within the crib 14 there is provided rotating cross-head assembly 32 which is rotatable about a centrally located vertical axis 34 in a direction opposite that of the cross-head 26 and shown by arrows 3 6 (FIG. 2). The cross-head assembly 26 is supported for rotation in the crib 12 by a shaft 38 which is journaled in a central support column 40 and the shaft is driven by a gear reducer 44 positioned below the crib and coupled to the shaft by means of a coupling 42. The crosshead 32 is supported for rotation in the crib 14 by a shaft 46 which is journaled in a central support column 48 and the shaft is driven by a gear reducer 52 positioned below the crib and coupled to the shaft by means of a coupling 50. The

gear reducers

44 and 52 are interconnected by a coupling unit 54 and are driven by a single power source such as an electric motor (not shown) by means of a pulley 56 and belt drive (not shown). The gear reducers are interconnected to one another and driven by a common power source in order that the crosshead assemblies 26 and 32 will rotate in selected synchronous relation to one another as can be seen from the positions of the cross-heads shown in the drawings and for reasons more fully explained in the previously mentioned US. Patent No. 2,943,801.

The cross-head assemblies 26 and 32 are substantially identical in construction and, hence, only the cross-head assembly 26 will be described in detail and similar components of the cross-head assembly 32 have been assigned the same reference numerals as their counterparts in the cross-head assembly 26. The cross-head assembly 26 includes a main head assembly 60 which is preferably formed of cast metal and which is secured to rotate with the shaft 38 by suitable means such as a splined or keyed connection. The head assembly casting '60 includes a pair of radially disposed, oppositely extending

scraper support arms

62 and 64 which carry an outer scraper assembly 66 and an inner scraper assembly 68, respectively. The outer scraper assembly-66 includes a curved scraper or blade 66a, the outer edge of which moves in a path closely adjacent to the cylindrical side Walls of the cribs and the lower edge of which moves in a path closely adjacent to the base plate 16:: of the mulling machine. As the cross-head assembly 26 rotates, the blade 66a moves material inwardly away from the periphery of the cribs into a circular path of a pair of mulling wheels 70. The inner scraper assembly 68 includes a scraper or blade 68a, the inner edge of which moves in a path closely adjacent the central support column 40 and a lower edge which moves in a path closely adjacent to the base plate 16a. As the cross-head assembly 26 rotates, the blade 68a moves material from the central portion of the crib outwardly into the path of the mulling wheels.

In order to provide for the mulling and pulverization of the material in the crib, there are provided a pair of mulling wheels 70 which are disposed on opposite sides of the main head assembly 60. Each of the wheels 70 is mounted to be freely rotatable on one of a pair of horizontally disposed, outwardly extending wheel carrying axles 72. The axles 72 are positioned to extend generally normal to the

scraper support arms

62 and 64 and are supported at their inner ends by a pair of independent support members 74 which are disposed on opposite sides of the main head assembly 60.

The support members 74 are journaled on the head assembly 60 'to rotate about horizontally disposed axes 76 which are parallel to the wheel axles 72. As each member 74 pivots about its respective pivot axis 76, the mullin-g wheel 70 carried thereby is moved toward or away from the base plate 16a of the mulling machine. Each of the support members 74 is formed with a downwardly extending leg 74a, the lower end of which supports the inner end of one of the wheel axles 72. Each support member 74 is also provided with an upstanding actuating arm 74b which extends upwardly in a direction generally opposite to and away from the wheel axle 72 carried by the respective support member.

Referring now to the right hand portion of FIG. 1, in order to limit the downward movement of the mulling wheels 70 as the members 74 pivotally move in the direction of the arrow 78, stop lugs 60a are formed on opposite sides of the main head assembly 60. Each of the stop lugs 66a is engageable with an adjustable stop bolt 80 which is threadedly received in a stop arm 82 formed on each support member 74. By adjustment of the stop bolt 80, the lower limit of the downward movement of the mulling wheels 70 can :be easily adjusted.

The free weight of each mulling wheel 70, its supporting axle 72 and leg 74a tends to cause pivotal movement of each support member 74 in the direction of the arrow 78 and consequently a considerable amount of mulling pressure between the wheel and the material in the crib is present because of the weight of these components. .As the cross-head assembly rotates in the crib, the wheels 70 tend to ride up over material in the crib causing pivotal movement of the support members 74 in an opposite direction as indicated by the arrow 84. As this happens the stop bolts 80 on the members 74 move upwardly away from contact with the stop lugs 60a and the upstanding actuating arms 74b move in the direction of the arrow 86.

In order to bias the mulling Wheels 70 downwardly toward the base plate 16a to increase the mulling pressure, there is provided a pair of independent biasing assemblies including coiled tension springs 88. The tension springs 88 are of the elongated coiled type having the coils at opposite ends thereof tapering to a reduced diameter in order to provide engaging end surfaces serving as stops for retaining the inner ends of axially positioned

rods

90 and 92. The inner ends of these rods are provided with conically shaped heads or stops (shown in dotted lines in FIG. 2) which engage the end coils of the springs 88 in order to limit the outward movement of the rods and to retain the rod ends within the springs. The outer ends of the rods 90 are pivotally connected to the upper ends of the upstanding actuating arms 74b and the outer ends of the rods 92 are connected to upwardly extending brackets 94 which are fixedly secured to the main head casting 60 by means of a plurality of bolts 96. The rods 92 extend through the brackets 94 and are threaded to accommodate stop nuts 92a which may be tightened or loosened to adjust the tension on the springs 88. By adjusting the nuts 92a, the tension on the springs 88 can be set to provide the necessary force for biasing the actuating arms 74b to urge the mulling wheels 70 downwardly toward the base plate 16a to obtain the desired mulling pressure; Should the mulling wheels 70 ride upwardly over an accumulation of material in the crib, the biasing force urging the wheels downwardly is.

increased because of the increased tension on the springs 88, thus tending to break up the accumulation of the material and level it out in the crib. By providing for ad- V justment of the tension on the springs 88, a range of mulling pressures is obtainable in order to provide the desired amount of mulling or pulverization needed for a given material.

The pivot axes 76 of the members 74 are positioned forwardly of the wheel axles 72 in the direction of rotation of the cross-head assemblies (FIG. 2) so that the upward movement of the mulling wheels 70 is opposed by the force tension springs 88 and the weight of the wheels, axles and support members 74. This construction greatly reduces the possibility of a jam up should a foreign object become wedged between the wheel and the base plate since the wheels can ride up and over most of such objects.

Referring now to FIGS. 3 and 4 of the drawings, there is illustrated another embodiment of a mulling machine constructed in accordance with the present invention and indicated generally by the reference numeral 110. The machine is of the single stage type, and includes a cylindrical material receiving crib 112 having a bottom or base plate 116. The crib 112 is provided with a replaceable wall liner 112a and the bottom is provided with a replaceable wear plate 116a. The machine is supported from a floor or other surface 124 by means of legs 122 secured to the bottom of the crib 112.

Within the material receiving crib 112, there is provided a rotating cross-head assembly 126 which is rotatable about a centrally located vertically extending axis 128 in the direction indicated by the arrow 130 (FIG. 4). The cross-head assembly 126 is supported for rotation in the crib 112 on a shaft 138 which is journaled in a central support column 140 and the shaft is driven by a gear reducer 144 positioned below the crib and coupled to the shaft by means of a coupling 142. The gear reducer 144 is driven by a suitable power source such as the electric motor 146 which is drivingly connected to the reducer by a suit-able belt drive 148.

The cross-head assembly 126 includes a main head assembly 160 which is preferably formed of cast metal and which is secured to rotate with the shaft 138 by suitable means such as a splined or keyed connection. The casting 160 includes a pair of radially disposed, oppositely extending scraper support arms 162 and 164 which carry an outer scraper assembly 166 and an inner scraper assembly 168, respectively.

The outer scraper assembly 166 includes a curved scraper blade 166a, the outer edge of which moves in a path closely adjacent to the wall 112a of the crib and the lower edge of which moves in a path closely adja: cent the bottom wear plate 116a. As the cross-head assembly 126 rotates, the blade 166a moves material inwardly away from the periphery of the crib into a circular path of a pair of mulling wheels 1711. The inner scraper assembly 168 includes a curved scraper blade 168a, the inner edge of which moves in a path closely adjacent the central support column 140 and the bottom edge of which moves in a path closely adjacent the bottom wear plate 116a. As the cross-head assembly 126 rotates, the scraper 166a moves material outwardly away from the central portion of the crib into the path of the mulling wheels.

In order to provide for mulling and pulverization of the material in the crib, there is provided a pair of mulling wheels 170 which are disposed on opposite sides of the main head assembly casting 160. Each of the wheels 170 is mounted to be freely rotatable on one of a pair of horizontally disposed oppositely extending wheel carrying axles 172. The axles 172 are positioned to extend in a direction generally normal to the scraper support arms 162 and 164 and are supported at their inner ends by a pair of independent support members 174 which are disposed on opposite sides of the main head assembly 160.

The support members 174 are journaled on the head assembly 160 to rotate about horizontally disposed pivot axes 176 which are positioned to lie in parallel relation to the axles 172. As each support member 174 pivots about its respective pivot axis 176, the mulling wheel 170 carried thereby is either raised or lowered in relation to the base plate 116a. Each support member 174 is formed with a downwardly extending leg 174a, the lower end of which supports the inner end of one of the Wheel axles 172. Each support member 174 is provided with an upstanding actuating arm 174b which extends upwardly in a direction generally opposite to and away from the wheel axle 172 carried by the respective support member.

In order to limit the downward movement of the mulling wheels 170 as the support members 174 pivotally move in the direction of the arrow 178 (FIG. 3), the main head assembly 160 is provided with stop lugs 16012 which extend outwardly on opposite sides thereof. Each of the stop lugs 160a is engageable with an adjustable stop bolt 180 which is threadedly received in a stop arm 182 formed on each support member 174. By adjustment of the stop bolt 180 the lower limit of the downward 6 movement of the mulling wheels can be adjusted to the level desired.

Referring now to the elevational view of FIG. 3, the upper end of the actuating arm -174b of each support member 174 is connected to to the inner ends of biasing spring assemblies and 182, respectively. The biasing

spring assemblies

180 and 182 are opposed to one another and are generally similar in construction to the'biasiug springs 88 previously described. The outer ends of the biasing spring assemblies 180 are adjustably secured to the upper ends of brackets 184 which are bolted on opposite sides of the head assembly 160. The outer ends of the biasing spring assemblies 182 are adjustably secured to the upper ends of the brackets 186 which are secured on the scraper support arms 162 and 164. Tension on the

spring assemblies

180 and 182 is adjusted by means of adjusting nuts 188 which are threaded on outwardly extending rods 190 of the spring assemblies. When the mulling wheels 170 are moved upwardly away from the wear plate 116a, the biasing spring assemblies 180 are under tension and the tension in the spring assemblies 182 is relaxed. When the mulling wheels 170 move downwardly toward the wear plate 116a, the spring assemblies 182 are then under tension and the tension in the spring assemblies 180 is relaxed. The

spring assemblies

180 and 182 are connected in direct opposition to one another and can be adjusted to provide a relatively constant mulling pressure between the wheels 170 and material in the crib regardless of the upward or downward movement of the wheels. With two opposed spring assemblies of the present invention, the mulling pressure can be main tained relatively constant as the increase of tension force on one assembly will be balanced by the relaxing of the tension on the other. Also, by proper adjustment and balancing of the

spring assemblies

180 and 182, mulling pressures are obtained which are in a range including pressure both less than as well as greater than those obtained with the free weight of the mulling wheel alone. This is a decided advantage in that the muller can be used on materials which would be too finely pulverized by mulling pressures as great as those caused by the weight of the wheels alone as well as materials requiring mulling pressure much greater than that caused by the weight of the wheels alone. By use of the opposing spring assemblies, the mulling pressure, once adjusted to the desired range, is relatively constant even though the mulling wheels may move up and down and a wide range of mulling pressures is available thus making the machine readily usable for a wide variety of materials requiring a wide range of mulling pressures.

While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since many modifications may be made and it is therefore contemplated by the appended claims to cover any such modifications as fall within the true spirit and scope of the invention.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A mulling machine comprising a material receiving crib having a base plate; cross-head means mounted in said crib to rotate about a vertical axis; at least one mulling wheel supported by said cross-head means to move therewith and freely rotatable on an outwardly extending, horizontally disposed axle; axle support means carrying said axle and journaled on said cross-head means for pivotal movement about a horizontal pivot axis, said support means including an upstanding actuating arm extending away from said axle; first spring means for resiliently biasing said arm in a direction to urge said mulling wheel downwardly toward said base plate and opposed second spring biasing means for resiliently biasing said arm in a directon to urge said mulling wheel upwardly away from said base plate.

2. Apparatus as defined in claim 1 wherein said first and second spring biasing means include a pair of opposed tension spring assemblies, the inner ends of both said assemblies pivotally secured to said actuating arm.

3. Apparatus as defined in claim 2 wherein each of said spring assemblies includes a coiled tension spring having axially disposed rods extending from the ends thereof and stop means carried on the inner ends of said rods for engaging the end coils of said spring to limit the outward travel of said rods and apply tensile forces to said springs.

4. Apparatus as defined in claim 3 wherein the outer ends of the rods at the inner ends of said opposed spring assemblies are pivotally secured to said actuating arm and the outer ends of the rods at the outer ends of said opposed spring assemblies are adjustably secured to said cross-head.

5. A mulling machine comprising a material receiving crib having a base plate; cross-head means mounted in said crib to rotate about a vertical axis; a pair of mulling wheels disposed on opposite sides of said cross-head means, said wheels mounted to freely rotate on independent, oppositely outward extending horizontally disposed axles; a pair of independent support means, each of said support means carrying one of said axles and pivotally mounted on opposite sides of said cross-head means for pivotal movement about horizontal pivot axes, each of said support means including an upstanding actuating arm extending away from the axle carried thereby; first spring means for resiliently biasing the actuation arm of each support means in a direction urging the mulling wheel supported thereby downwardly toward said base plate and permitting free movement of said mulling wheels downwardly toward said base plate; and opposed second spring means for resiliently biasing the actuating arm of each support means in a direction urging the mulling Wheel supported thereby upwardly away from said base plate and permitting free movement of said mulling wheels upwardly from said base plate.

6. Apparatus as defined in claim 5 wherein said first spring means includes a pair of independent tension spring assemblies, each having one end secured to said crosshead means and the other end secured to one of said second actuating arms, said opposed spring means including a pair of independent spring assemblies, each having one end secured to said cross-head means and the other end secured to one of said actuating arms.

7. Apparatus -.as'defined in claim 1 wherein there is additionally provided adjustable stop means for limiting the downward movement of said mulling wheels; said stop means including an adjustable member threadedly mounted on a selected one of said first two-mentioned means for engagement with a relatively fixed member on the other of said first two-mentioned means; and first and second adjusting means for adjusting the biasing forces exerted on said actuating arm by said first and second spring biasing means, respectively.

8. A mulling machine comprising a material receiving crib having a base plate; a cross-head mounted in said crib to rotate about a vertical axis; at least one mulling wheel supported by said cross-head to move therewith and freely rotatable on an outwardly extending horizontally disposed movable axle; an axle support member carrying said axle and pivotally mounted on said cross-head to rotate about a second axis parallel to said axle, said support member including an actuating arm extending radially outward from said second axis in a direction generally opposite from said axle, and means for biasing said actuating arm about said second axis in a direction urging said mulling wheel downwardly toward said base plate and permitting free movement of said wheel in a downwardly direction.

9. A mulling machine comprising a material receiving crib having a base plate; a cross-head mounted in said crib to rotate in one direction about a vertical axis; at least one mulling wheel supported by said cross-head to urging said mulling wheel downwardly toward said base plate and permitting free movement of said Wheel downwardly toward said base plate.

16. A mulling machine comprising a material receiving crib having a base plate, a cross-head in said crib mounted to rotate therein about a vertical axis; a pair of mulling wheels disposed on opposite sides of said cross-head;

said mulling wheels mounted to freely rotate on independent oppositely outwardly extending, horizontally disposed axles; a pair of independent support members, each carrying one of said axles with a mulling wheel thereon and pivotally mounted on opposite sides of said crosshead for movement about horizontal pivot axes parallel to said axles; each of said support members including an actuating arm extending radially outward from the pivot axis thereof in a direction generally opposite from the axle carried thereby and means for biasing each of said actuating arms in a direction urging the downward movement of the mulling wheel carried on the respective support member and permitting free movement of the wheels downwardly toward said base plate.

11. A mulling machine comprising a material receiving crib having a base plate; a cross-head mounted in said crib to rotate about a vertical axis; at least one mulling wheel supported by said cross-head to move therewith and freely rotatable on an outwardly extending horizontally disposed movable axle; an axle support member carrying said axle and pivotally mounted on said cross-headto rotate aboutv a horizontal axis parallel to said axle, said support member including an actuating arm extending radially outward from said horizontal axis in a direction generally opposite from said axle and spring means engageable with said cross-head and said actuating arm for biasing said support member about said horizontal axis in a direction urging said mulling wheel downwardly toward said base plate and permitting free movement of said wheel downwardly toward said base plate, and adjustable stop means for limiting the downward movement of said mulling wheel.

12. A mulling machine comprising a material receiving crib having a base plate; a cross-head mounted in said crib to rotate in one direction about a vertical axis; at least one mulling wheel supported by said cross-head to move therewith and freely rotatable on an outwardly extending horizontally disposed movable axle; an axle support member carrying said axle and pivotally mounted on said cross-head to rotate about a horizontal axis parallel to and spaced from said axle in the direction of rotation, said support member including an actuating arm extending radially outward from said horizontal axis in a direction generally opposite from said axle and spring means engageable with said cross-head and said actuating arm for resiliently biasing said support member about said horizontal axis in a direction urging said mulling wheel downwardly toward said base plate and permitting free movement of said wheel downwardly toward said base plate, and adjustable stop means for limiting the downward movement of said mulling wheel, said stop means including an element formed on said support member engageable with an element on said cross-head to limit the rotational movement of said support member about said axis.

13. Apparatus as defined in claim 9 wherein said spring means includes a coiled tension spring having its ends 9 2 interconnected with said actuating arm and said crosshead respectively.

14. Apparatus as defined in claim 13 wherein said spring means additionally includes means for adjusting the tension on said coiled spring.

References Cited UNITED STATES PATENTS 2,461,176 2/1949 Piper 241-128 X McIlvaine 241-432 X Horth 241-124 X McIlvaine et a1. 241124 Pellizzetti 241126 ROBERT C. RIORDON, Primary Examiner.

DONALD KELLY, Assistant Examiner.

Claims

1. A MULLING MACHINE COMPRISING A MATERIAL RECEIVING CRIB HAVING A BASE PLATE; CROSS-HEAD MEANS MOUNTED IN SAID CRIB TO ROTATE ABOUT A VERTICAL AXIS; AT LEAST ONE MULLING WHEEL SUPPORTED BY SAID CROSS-HEAD MEANS TO MOVE THEREWITH AND FREELY ROTATABLE ON AN OUTWARDLY EX TENDING, HORIZONTALLY DISPOSED AXLE; AXLE SUPPORT MEANS CARRYING SAID AXLE AND JOURNALED ON SAID CROSS-HEAD MEANS FOR POVOTAL MOVEMENT ABOUT A HORIZONTAL PIVOT AXIS, SAID SUPPORT MEANS INCLUDING AN UPSTANDING ACTUATING ARM EXTENDING AWAY FROM SAID AXLE; FIRST SPRING MEANS FOR RESILIENTLY BIASING SAID ARM IN A DIRECTION TO URGE SAID MULLING WHEEL DOWNWARDLY TOWARD SAID BASE PLATE AND OPPOSED SECOND SPRING BIASING MEANS FOR RESILIENTLY BIASING SAID ARM IN A DIRECTION TO URGE SAID MULLING WHEEL UPWARDLY AWAY FROM SAID BASE PLATE.