US3346974A

US3346974A - Bulldozer and bucket

Info

Publication number: US3346974A
Application number: US446284A
Authority: US
Inventors: John A Haynes
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-04-07
Filing date: 1965-04-07
Publication date: 1967-10-17
Anticipated expiration: 1984-10-17

Description

06%. 17, J. A HAYNES BULLDOZER AND BUCKET 2 Sheets-Sheet 1 Filed April 7, 1965 [N VEN TOR. Hgg/Yes Jo/W? A BY /Mf Affarmggs 1957 J. A. HAYNES BULLDOZER AND BUCKET 2 Sheets-Sheet 2 Filed April 7. 1965 INVENTOR. John A. Hgz nes BY ,MYLM

A f forwggs United States Patent ()fifice 3,346,974 Patented Oct. 17, 1967 3,346,974 BULLDOZER AND BUCKET John A. Haynes, 14B Brown Ave., Sylacauga, Ala. 35150 Filed Apr. 7, 1965, Ser. No. 446,284 16 Claims. (Cl. 37-1175) This invention relates to a bulldozer and bucket and more particularly to apparatus which shall be adapted for selective use as a bulldozer or bucket.

An object of my invention is to provide a bulldozer and bucket which shall be operable from a translatable frame such as a tractor, Caterpillar or the like without having to remove the blade when the apparatus is employed as a bucket.

Another object of my invention is to provide a bulldozer and bucket of the character designated in which the blade forms a rear wall for a forwardly opening bucket, thus reducing the number of parts as well as reducing the time required to change from a bulldozer to a bucket and vice versa.

A further object of my invention is to provide a bulldozer and bucket of the character designated in which the forward edge of the bottom wall limits rearward movement of the blade to thus absorb forces exerted against the lower end of the blade while the blade is in its lowermost position for operation as a bulldozer blade.

A further object of my invention is to provide apparatus of the character designated in which the blade is supported from side walls of the bucket by crank arms which are connected to a shaft-like member, the crank arms and the shaft-like member lying in a common plane which passes through the lower end of the blade whereby upward force on the blade is exerted in this common plane.

A still further object of my invention is to provide a bulldozer and bucket construction of the character designated which shall be simple of construction, economical of manufacture and one which may be mounted on various type translatable frames with a minimum of effort.

Heretofore in the art to which my invention relates, various types of bulldozer blades and buckets have been proposed for handling materials. However, such apparatus has necessitated the removal of the bulldozer blade from the bucket while the bucket portion of the apparatus is employed. In accordance with my present invention, the bulldozer blade forms a rear wall of the bucket while the blade is in its rearmost position. On the other hand, when the blade is moved to its forward position, it is adapted to move downwardly whereby the lower edge of the blade is positioned below the forward edge of the bottom of the bucket. The bottom of the bucket thus limits rearward movement of the blade and absorbs forces exerted against the lower end of the blade. Improved means is provided to move the blade selectively from a forward position to a rearward position whereby the apparatus may be employed selectively as a bulldozer and bucket.

Apparatus embodying features of my invention is illustrated in the accompanying drawings, forming a part of this application, in which:

FIG. 1 is a side elevational view, party broken away, showing the bulldozer and bucket unit mounted on a Caterpillar type tractor;

FIG. 2 is a front elevational view of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged sectional view taken generally along the line 3-3 of FIG. 2;

FIG. 4 is a fragmental view corresponding to FIG. 3 but showing the blade moved to its rearmost position where it is employed as a rear wall for the bucket;

FIG. 5 is a fragmental view, partly broken away, taken generally along the line 5-5 of FIG. 3;

FIG. 6 is an enlarged, sectional view taken generally along line 6-6 of FIG. 5;

FIG. 7 is a frag-mental view taken generally along the line 7-7 of FIG. 6;

FIG. 8 is a vertical sectional view corresponding to FIG. 3 but showing a modified form of my invention;

FIG. 9 is a fragmental view taken generally along the line 9-9 of FIG. 8;

FIG. 10 is a fragmental view taken along the line 10-10 of FIG. 9 while the blade is in its forwardmost, lowered position;

FIG. 11 is a fragmental, sectional view taken along the line 10-10 of FIG. 9 while the blade is in its forwardmost, raised position;

FIG. 12 is a fragmental, sectional view taken along the line 10-10 of FIG. 9 while the blade is in its rearmost position to serve as a back wall for the bucket;

FIG. 13 is a fragmental, sectional view taken generally along the line 13-13 of FIG. 9; and,

FIG. 14 is a fragmental view showing a modified form of my invention wherein the blade is actuated by a lever arm which in turn is operatively connected to a fluid pressure operated cylinder.

Referring now to the drawings for a better understanding of my invention, I show a translatable frame 10 which may be in the form of a conventional type tractor, crawler type tractor, or the like. Mounted on the translatable frame 10 by suitable linkage indicated generally at 11 is a bulldozer blade and bucket unit indicated generally at 12. The linkage 11 is moved to selected positions relative to the translatable frame 10 by suitable fluid pressure operated cylinders 13 whereby the blade and bucket unit 12 may be raised or lowered to selected positions for use as a bulldozer blade or as a bucket. The blade and bucket unit 12 comprises a pair of horizontally spaced side walls 14 which are connected to each other at their lower ends by a bottom wall 16. Rear portions of the side walls 14 are connected to each other by

transverse members

17 and 18 which in turn are operatively connected to the translatable frame 10 by the members 11, as shown. The

transverse members

17 and 18 are connected to each other intermediate the ends thereof by a connecting member 19 which serves as a brace between the

transverse members

17 and 18 and for a purpose to be set forth hereinafter.

Mounted for pivotal movement between the side walls 14 is a blade 21. Mounted on and adapted for rotation relative to the blade 21 is an elongated shaft-like member 22. Suitable bearing members 23 are carried by the rear surface of the blade 21 in position to receive the shaftlike member 22, as shown in FIG. 5. Secured to each end of the elongated shaft-like member 22 is a laterally projecting arm24; Secured to the upper end of each of the arms 24 is a horizontally extending member 26 which is adapted for rotation in a suitable opening 27 provided in the adjacent side wall 14. The outer end of each member 26 is threaded for receiving a nut 28 which retains the horizontal members 26 in assembled relationship to the side walls 14. The upper portion of each arm 24, together with the horizontally extending member 26 thus define crank arms which are connected rigidly to the shaft-like member 22. Suitable recesses 29 are provided at each end of the blade 21 whereby the crank arms are adapted for free rotation relative thereto. The recesses 29 are defined by forwardly projecting arcuate members 31 whereby materials engaged by the blade 21 do not pass through the recesses.

Formed integrally with the arm 24 is a depending member 32 which is adapted to extend alongside the rear side of the blade 21, as shown in FIGS. 3-5. Mounted for horizontal movement on the rear side of the blade 21 is an elongated latch pin 33 which is adapted to engage the depending member 32, as shown in FIG. 5, while the blade is in its forward position. The latch pin 33 passes through a housing 34 which is mounted on the rear side of the blade 21, as shown. A spring abutment 36 is carried by the pin 33 and a spring 37 surrounds the pin intermediate the spring abutment 36 and a side of the housing 34 whereby the spring urges the latch pin 33 toward the adjacent side wall 14 and into engagement with the adjacent depending member 32. Pivotally connected to the latch pin 33 by a pivot pin 38 is an actuating rod 39 which passes through suitable bearing members 41 carried by the rear side of the blade 21 whereby the rod 39 is adapted for axial movement. The other end of the rod 39 is pivotally connected by a pivot pin 42 to a lever arm 43 which in turn is pivotally mounted on a pin 44. A roller 46 is carried by the free end of each of the arms 43 in position to engage a bearing surface 47 carried by an elongated rack indicated generally at ,48. That is, the rack 48 is provided with a bearing surface 47 at each side thereof which merges with an outwardly curved cam surface 49 which in turn communicates with longitudinally extending bearing surfaces 51, as shown in FIG. 7.

Secured to the lower end of the rack 48 is a piston rod 52 of a fluid pressure operated cylinder 53. As shown in FIGS. and 6, the cylinder 53 is mounted on the rear side of the blade 21 whereby the piston rod 52 is adapted to reciprocate the rack 48. The rack 48 is mounted for sliding movement in suitable guide members 54 which are carried by the rear side of the blade 21, as shown.

The teeth of the rack 48 mesh with a pinion 56 which is connected to the shaft-like member 22 by a lost motion connector which permits a limited amount of initial movement of the pinion relative to the shaft-like member 22. The lost motion connector is provided by providing arcuate recesses 57 in the pinion 56 in position to receive outwardly projecting detents 58 carried by the shaft-like member 22, as shown in FIG. 6. That is, the recesses 57 permit a limited amount of angular movement of the detents 58 before engagement wtih the ends of the recesses 57.

Initial movement of the piston rod 52 in a downward direction causes the rack 48 to move downward whereupon the detents 58 rotate relative to the recesses 57. This initial movement of the rack 48 causes the rollers 46 to engage the cam surfaces 49 and thus move outwardly whereupon they ride along the bearing surfaces 51. As the rollers 46 are moved outwardly by the cam surfaces 49, each arm 43 is pivoted about its pivot pin 44 whereupon the actuating rods 39 and the latch pins '33 carried thereby are moved inwardly to thus disengage the depending members 32. After the latch pins 33 have disengaged the depending members 32, the crank arms at the ends of the shaft-like member 22 are free to rotate relative to the openings 29.

Continued movement of the rack 48 in a downward direction after the depending members 32 have been freed causes this pinion 56 .to rotate in the direction of the arrow 59 to thereby impart rotation to the shaft-like member 22 about the horizontal members 26 whereupon the arms 24 and the blade 21 move from the solid line position to the dotted line position shown in FIG. 3. As the blade 21 moves from the solid line position to the dotted line position, it is elevated from a position below the forward edge of the bottom wall 16 to a position above the bottom wall 16. While the blade 21 is in the lowered, solid line position shown in FIG. 3, the forward edge of the bottom wall 16 limits rearward movement of the lower end of the blade 21 whereby the horizontal forces exerted against the lower end of the blade 21 are absorbed by the forward edge of the bottom wall 16. The lower end of the blade 21 carries a suitable cutter element 61, as shown. Also, while the blade 21 is in the lowered or solid line position shown in FIG. 3, the shaft 22 and the horizontal member 26 lie in a common plane which also extends through the lower end of the blade 21. Accordingly, any upward forces exerted against the blade 21 are transmitted in this common plane which extends through the shaft 22 and the horizontal member 26 whereby there is no pivotal movement of the crank arms defined by the arms 24 and the horizontal members 26. i

The plate 21 is moved from the dotted line position shown in FIG. 3 to the position shown in FIG. 4 by a piston rod 62 which is connected to the blade 21 by a suitable pivot pin 63. The piston rod 62 is actuated by a fluid pressure operated cylinder 64 which is pivotally connected to the member 19 by a pivot pin 66. Upon movement of the blade 21 to the raised or dotted line position shown in FIG. 3, the blade is then free to move rearwardly to the position shown in FIG. 4. That is, after the blade 21 is raised to the dotted line position shown in FIG. 3, the cylinder. 64 is actuated to move the piston rod 62 inwardly of the cylinder 64, thus to move to the rearmost position as shown in FIG. 4 to thereby serve as a rear wall for a bucket unit. Accordingly, the blade 21 may be moved selectively from the solid line position shown in FIG. 3 to the position shown in FIG. 4 whereby the unit may be employed selectively as a bulldozer blade and as a bucket.

From the foregoing description, the operation of my improved apparatus shown in FIGS. 1-7 will be readily understood. To use the unit as a bulldozer blade, the blade 21 is moved to the solid line position shown in FIG. 3 whereupon the lower edge thereof extends below the forward edge of the bottom wall 16. Accordingly, upon forward movement of the unit, the forward edge of the bottom wall absorbs forces exerted in a horizontal direction against the lower end of the blade. The blade 21 is held against vertical movement due to the fact that the shaft 22 and the horizontal member 26 extend in a common plane which passes through the lower end of the blade thus preventing rotation of the shaft-like member relative to the member 26.

To employ the unit as a bucket, the piston 53 is energized whereupon the piston rod 52 and rack 48are moved downwardly. Initial downward movementof the rack 48 causes the roller 46 to engage the cam surfaces 49 and thus move outwardly into engagement with the bearing surfaces 51. This outward movement of the rollers 46 causes the latch pins 33 to release the depending members 32 whereupon the arms 24 are free to rotate relative to the blade 21. Continued downward movement of the rack 48 imparts rotary motion to the pinion 56 due to engagement of the detents 58 with the recesses 57. As the pinion 56 rotates in the direction of the arrow 59, the

arm 24 and the blade 21 move from the solid line position to the dotted line position shown in FIG. 3. The fluid pressure operated cylinder 64 is then energized whereupon the piston rod 62 moves the blade 21 from the dotted line position shown in FIG. 3 to the position shown in FIG. 4. In the position shown in FIG. 4, the blade 21 serves as a rear wall for a bucket whereby the apparatus may be employed to convey materials from place to place.

In FIGS. 8-13 of the drawings, I show a modified form of my invention in which a blade 21 is adapted for pivotal movement between a pair of side walls 14. A bottom wall 16 extends between the lower edges of the side walls 14 and is rigidly secured thereto whereby the side walls 14 are held in horizontally spaced relation to each other as the side walls 14 are held in spaced relation to each other by bottom wall 16 in the apparatus shown in FIGS. 1-7. The rear ends of the side walls 14- are connected to each other by

transverse members

17 and 18 Also, the

transverse members

17 and 18 are connected to each other by a brace member 19 The lower end of the blade 21 is provided with a cutting edge 61*, as shown in FIG. 8. The

transverse member

17 and 18 also carry rearwardly extending brackets whereby the unit may be pivotally attached to a suitable linkage, such as the linkage 11 shown in FIG. 1.

Secured to each end of the blade 21 adjacent the upper end thereof is an outwardly extending bracket 67 having a generally rectangular portion 68 at the outer end thereof which extends parallel to the blade 21*. Each rectangular portion 68 passes through an opening provided in the upper portion of the adjacent side wall 14*. Each opening in the side wall 14 is provided with a vertically extending lower portion 69 which is adapted to receive the rectangular portion 68 of the bracket 67 with a snug fit, as shown in FIG. 10. The upper portion of the opening through each side wall 14 is provided with diagonally extending

portions

71 and 72. The diagonal portion of the opening 71 is provided with

side portions

73 and 74 while the diagonal portion 72 communicates at one side with the depending opening 69 and is provided with a side wall 76 at the other side thereof. Accordingly, the rectangular member 68 is adapted to move from the lower position shown in FIGS. 8 and 10 to an elevated position shown in FIG. 11 whereby the lower end of blade 21 is moved from a lower position beneath the forward edge of the bottom wall 16 to a position above the forward edge of the bottom wall 16*. Continued pivotal movement of the plate 21 relative to the side walls 14 causes the rectangular member 68 to move from the position shown in FIG. 11 to the position shown in FIG. 12 whereby it engages the

walls

73 and 76 of the opening through the side wall 14.

Secured to the bracket 67 adjacent each side of the adjacent side wall 14 is a disc-like member 77 which completely covers the opening through the side walls 14 to thereby prevent the ingress of foreign materials, such as dirt and the like inwardly of the opening. The disc-like members 77 are secured to the bracket 67 by suitable means, such as by welding or the like.

Pivotally connected to the lower portion of the blade 21 by a pivot pin 63 is a piston rod 62 of a fluid pressure operated cylinder 64 The cylinder 64 is pivotally connected to the member 19 by a suitable pivot pin 66 whereby the blade 21 is adapted to move from the solid line position shown in FIG. 8 to the dotted line position.

From the foregoing, the operation of the apparatus shown in FIGS. 813 will be readily understood. To operate the unit as a bulldozer blade, the blade is moved to the solid line position shown in FIG. 8 whereby the lower edge of the blade extends forwardly of and below the forward edge ofthe bottom wall 16*. The bottom wall 16 thus absorbs the forces exerted against the lower end of the blade 21 Since the piston rod 62 extends downwardly and forwardly relative to the blade, the piston rod would prevent upward movement of the blade while it is employed as a bulldozer blade. However, suitable means may be employed to lock the blade 21 in its lowermost position other than the use of the piston rod 62 and the fluid pressure operated cylinder 64*.

To use the apparatus shown in FIGS 8l3 as a bucket, the fiuid pressure operated cylinder 64 is actuated to move the blade to the dotted line position shown in FIG. 8. Initial movement of the blade 21* from the solid line position shown in FIG. 8 causes the blade and the rectangular portion 68 of the bracket 67 to move to the position shown in FIG. 11. Continued rearward movement of the blade 21* by the piston rod 62 causes the blade to move to the dotted line position shown in FIG. 8 whereupon the rectangular portion 68 moves to the position shown in FIG. 12. The rectangular portion 68 thus engages the

sides

73 and 76 of the opening through the side walls 14 whereby the blade is held in the dotted line position.

Referring now to FIG. 14 of the drawings, I show another modified form of my invention in which a lever arm 78 is secured rigidly to a shaft-like member 22. That is, the shaft-like member 22 would be mounted for rotation on the blade 21 as set forth hereinabove relative to the apparatus shown in FIGS 1-7. The outer end of the arm 78 is pivotally connected to the upper end of a piston rod 79 of a fluid pressure operated cylinder 81. The cylinder 81 is pivotally connected to the rear side of the blade 21 by a pivot pin 82 which passes through a suitable bracket 83 carried by the rear side of the blade 21. The blade 21 may be locked in lowered or raised position by suitable means, not shown.

From the foregoing, it will be seen that I have devised an improved bulldozer and bucket unit which may be converted selectively for use as a bulldozer blade or bucket with aminimum of etfort. By providing a blade which is adapted to extend forwardly of and below the forward edge of the bottom wall of the bucket, rearward move ment of the lower end of the blade is limited by the bottom wall and at the same time the bottom wall absorbs the forces exerted against the lower end of the blade. Also, by providing a blade which may be raised and then pivoted rearwardly to a position adjacent the rear ends of the side walls of the unit, the apparatus is adapted for use as a bucket without having to remove the blade from the side walls in any manner. Furthermore, by providing a bulldozer and bucket unit which is adapted for operation by fluid under pressure, the er tire apparatus may be actuated by the operator who rides on a translatable frame without the necessity of the operator leaving the translatable frame.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I clairn is:

1. In a bulldozer and bucket unit adapated to be supported on a translatable frame,

(a) a pair of horizontally spaced side walls,

(b) a bottom wall extending between and connected to lower portions of said side walls,

(c) a blade pivotally supported between said side walls and adapted for pivotal movement to a first position adjacent the front edge of said bottom wall in position to operate as a buldozer blade and to a second position adjacent the rear edge of said bottom wall in position to define with said side walls and said bottom wall a forwardly opening bucket,

(d) said blade being adapted to move selectively to a lower position with the lower edge thereof below the front edge of said bottom wall and to an upper position with the lower edge thereof above said front edge of said bottom wall,

(e) means to move said blade selectively to said lower position and said upper position while said blade is in said first position adjacent said front edge of the bottom wall, and

(f) means to move said blade while in raised position selectively to said first position and said second position.

2. In a bulldozer and bucket unit adapted to be supported on a translatable frame as defined in claim 1 in which rear portions of said side walls are connected to each other by transverse members which in turn are aperatively connected to the translatable frame.

3. In a bulldozer and bucket unit adapted to be supported on a translatable frame as defined in claim 1 in which the blade is moved selectively to said first position and said second position by a fiuid pressure operated cylinder unit operatively connected at one end to the rear side of said blade.

4. In a bulldozer and bucket unit as defined in claim 1 in which the blade is pivotally supported between said side walls adjacent the upper front edges of said side Walls.

5. In a bulldozer and bucket unit as defined in claim 1 7 in which the blade is held in said lower position by releasable latch means.

6. In a bulldozer and bucket unit as defined in claim 1 in which the blade is pivotally supported between said.

side walls by means comprising:

(a) an elongated shaft like member mounted for rotation on said blade and adapted to support said blade,

(b) crank-like arm members rotatably supported by said side Walls and connected to the ends of said shaft-like member in position to move said blade selectively to said lower position and said upper position upon rotation of said shaft-like member in opposite directions, and

(c) means to rotate said shaft-like member.

7. In a bulldozer and bucket unit as defined in claim 6 in which the means to rotate the shaft comprises a lever arm connected at one end to said shaft, and power actuating means operatively connected to the other end of said lever arm.

8. In a bulldozer and bucket unit as defined in claim 6 in which the crank arm and the shaft-like member extend in a common plane which also extends through the lower end of said blade while said blade is in said lower position.

9. In a bulldozer and bucket unit as defined in claim 6 in which the means to rotate said shaft comprises:

(a) a rack carried by and adapted for movement relative to the rear side of said blade,

(b) a pinion carried by said shaft-like member is in position to engage said rack, and

(c) means to move said rack to rotate said pinion.

10. In a bulldozer and bucket unit as defined in claim 9 in which said means to move said rack includes a fluid pressure operated cylinder which is carried by the rear side of said blade and operatively connected to said rack.

11. In a bulldozer and bucket unit as defined in claim 9 in which each crank arm comprises:

(a) an elongated arm connected to the adjacent end of said shaft, and

(b) means pivotally connecting one end of said elongated arm to said side wall adjacent thereto.

12. In a bulldozer and bucket unit as defined in claim 11 in which said elongated arm is connected to the end of said shaft intermediate the ends of said elongated arm whereby the other end of said elongated arm opposite said one end thereof which is pivotally connected to said side side wall extends beyond said shaft, and a releasable latch member is carried by said blade in position to engage said other end.

13. In a bulldozer and bucket unit as defined in claim 12 in which the releasable latch member comprises:

(a) an elongated latch adapted for movement relative to, said blade, (b) spring means urging said latch into engagement with said other end of said elongated arm, and (c) an actuating member carried by said rack in position to move said elongated latch out of engagement with said other end of the elongated arm upon rotation of said pinion in one direction.

14. In a bulldozer and bucket unit as defined in claim 13 in which the actuating member comprises a cam member carried by said rack in position to engage said latch.

15. In a bulldozer and bucket unit as defined in claim 12 in which a lost motion connection is provided between said pinion and said shaft whereby initial movement of said pinion releases said releasable latch member.

16. In a bulldozer and bucket unit as defined in claim 1 in which the blade is pivotally supported between said side walls by means comprising:

(a) support members carried by opposite ends of said blade and projecting outwardly therefrom,

(b) there being recesses in the upper forward portions of said side wallsin position to receive said support members,

(c) said recesses having a downwardly extending portion in position to receive said support members while said blade is in said first position adjacent said front edge of the bottom wall, and

(d) said recess having laterally extending portions in position to engage and support said support members while said blade is pivoted rearwardly away from saidfirst position.

References Cited UNITED STATES PATENTS 2,852,869 9/1958 Beyerstedt 37l17.5 3,092,920 6/1963 Benno 37-1175 3,122,248 2/1964 Campbell et al. 37-1175 X 3,250,028 5/1966 Hunger et al. 37-1175 ABRAHAM G. STONE, Primary Examiner.

R. L. HOLLISTER, Assistant Examiner.

Claims

1. IN A BULLDOZER AND BUCKET UNIT ADAPTED TO BE SUPPORTED ON A TRANSLATABLE FRAME, (A) A PAIR OF HORIZONTALLY SPACED SIDE WALLS, (B) A BOTTOM WALL EXTENDING BETWEEN AND CONNECTED TO LOWER PORTIONS OF SAID SIDE WALLS, (C) A BLADE PIVOTALLY SUPPORTED BETWEEN SAID SIDE WALLS AND ADAPTED FOR PIVOTAL MOVEMENT OF A FIRST POSITION ADJACENT THE FRONT EDGE OF SAID BOTTOM WALL IN POSITION TO OPERATE AS A BULDOZER BLADE AND TO A SECOND POSITION ADJACENT THE REAR EDGE OF SAID BOTTOM WALL IN POSITION TO DEFINE WITH SAID SIDE WALLS AND SAID BOTTOM WALL A FORWARDLY OPENING BUCKET, (D) SAID BLADE BEING ADAPTED TO MOVE SELECTIVELY TO A LOWER POSITION WITH THE LOWER EDGE THEREOF BELOW THE FRONT EDGE OF SAID BOTTOM WALL AND TO AN UPPER POSITION WITH THE LOWER EDGE THEREOF ABOVE SAID FRONT EDGE OF SAID BOTTOM WALL, (E) MEANS TO MOVE SAID BLADE SELECTIVELY TO SAID LOWER POSITION AND SAID UPPER POSITION WHILE SAID BLADE IS IN SAID FIRST POSITION ADJACENT SAID FRONT EDGE OF THE BOTTOM WALL, AND (F) MEANS TO MOVE SAID BLADE WHILE IN RAISED POSITION SELECTIVELY TO SAID FIRST POSITION AND SAID SECOND POSITION.