US3796104A

US3796104A - Counterbalanced drive for reciprocating cutter

Info

Publication number: US3796104A
Application number: US00170268A
Authority: US
Inventors: W Templeton
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-08-09
Filing date: 1971-08-09
Publication date: 1974-03-12
Anticipated expiration: 1991-03-12

Abstract

A counterbalanced transmission drive for reciprocating the sickle of a mower. A rocker arm pivotally mounted intermediate its ends is oscillated by an eccentric. One end of the rocker arm connects with the sickle. The opposite end carries a counterweight. By this arrangement, the counterweight and the sickle oscillate in opposing directions.

Description

[451 Mar. 12, 1974 United States Patent [1 1 Templeton 66 6 00 O M6 5 4656 7505 mm N mm m e i s oeM .laoa GNRC 4478 6666 9999 11.11 9981 6268 5993 8842 443 3333 Primary Examiner-Leonard l-l. Gerin [22] Filed:

Assistant ExamirierWesley S. Ratliff, Jr.

Attorney, Agent, or FirmWatts, Hoffmann, Fisher & Heinke Co.

T C A R T S B A 1 7 5 l 68 01 my 62 1 NF 4 7 z 4 4 7 [52] US. [51] Int.

[58] Field of i Z g?gb g2} 1 A counterbalanced transmission drive for reciprocating the sickle of a mower. A rocker arm pivotally Refrences Cited mounted intermediate its ends is oscillated by an ec- UNITED STATES PATENTS centric. One end of the rocker arm connects with the sickle. The opposite end carries a counterweight. By

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SHEET 2 UF 4 INVENTOR. WILLIAM E.TEMPLETON W, JJ M ATTORNEYS PATENTED MAR 12 974 SHEEI 3 BF 4 2 we Q Q 7 miminwzwv slvesilo x SHEET ll 0F 4 ATTORNEYS WILLIAM EQTEMPLE'I ON BACKGROUND OF THE INVENTION ance in one direction while driving the sickle in the op posite direction. Many proposed counterbalance drives utilize the momentum of the counterweight to provide added drive momentum in reversingthe direction of the sickle. In such arrangements, the counterweight acts as a flywheel. When the sickle becomes jammed by a foreign object, such drive momentum as is imparted to the sickle by the counterweight frequently causes substantial breakage of or other damage to components of the cutter.

SUMMARY OF THE PRESENT INVENTION The present invention overcomes the foregoing drawbacks of the prior art and provides an improved counterbalanced drive system which is exceptionally simple and inexpensive in design and yet which overcomes the problems cutter component damage due to counterweight momentum. The present invention provides a counterweight which is oscillate directly by the same rocker arm which oscillates the sickle. The counterweight is thereby caused to accelerate and decelerate in an. identical fashion with-the sickle. By this arrangement the momentum of the counterweight will be seen to be zero at the instant of reversal of direction of the sickle. Hence the counterweight does not act in the manner of a flywheel to impart a continuous momenturn of its own to the sickle. Rather, during sickle reversal, both the sickle and the counterweight cease movement, and no momentum is applied by the counterweight to effect sickle direction reversal.

Accordingly, the object of this invention is to provide a transmission for a mower having a novel and improved counterbalanced sickle drive system.

Other objects and a fuller understanding of the present invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS cated-by the line 4-4 of FIG. .1;

FIG. 5 is a: motiondiagram illustrating the movement of the rocker arm and counterweight; and,

FIG. 6 is a perspective view showing the connection between the rocker arm and the sickle head.

' DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a transmission assembly is illustrated generally at 10. The transmission includes a housing 11. The major operating components disposed within the housing include a drive shaft 12 which carries an eccentric 13. The eccentric is connected to a rocker arm 14 by a linkage 15. The rocker arm is pivotally mounted about a shaft 16 and comprises first and second legs l7, 18 extending in opposite directions from pivot shaft 16. The first leg 17 extends downwardly for connection to a sickle in a manner that will be explained later in greater detail. The second leg 18 extends upwardly and carries a counterweight 19. From the foregoing brief description, it will be apparentthat rotation of the drive shaft 12 will cause the eccentric 13 to oscillate the first and second

rocker arm legs

17 and 18 in opposing directions.

Turning to a more detailed description of the transmission, and referring particularly to FIG. 2, it will be seen that the housing 11 comprises three cast iron members. Left and

right housing members

20, 21 have a central housing member 22 sandwiched between them. The enclosed area between the

housing members

20, 22 defines a'first operating chamber 23, while the enclosed area between the

housing members

21, 22 defines a second operating chamber 24.

A hydraulic motor 25, the construction and arrangement of which is well known in the art, is secured to the left housing member 20. A motor shaft 26 extends into the chamber 23. through an opening 27 in the left housing member. A gear train including a drive pinion 28 and a meshing gear 29 serve to transmit rotational motion from the motor shaft 26 to the drive shaft 12.

Square keys

30, 31 respectively connect the drive pinion 28- to the motor sahft 26 and the gear 29 to the drive shaft 12.

The drive shaft 12 extends through the central housing member 22 from the chamber 23 to the chamber 24. The left end of the drive shaft 12 is rotatablysupported from the left housing member 20 by a roller bearing 32. Similarly, the right end of the drive shaft 12 is rotatably supported from the right housing member 21 by a roller bearing 33. The shaft 12 is axially located by a pair of

collars

34, 35 which respectively engage the inner races of the bearings 32, 33.

The collar 34 is slip fitted over the left end of the shaft 12. The collar 35 is rigidly secured to the right end of shaft 12 by means of a pin 36. A nut 37 carried by a threaded portion 38 of the shaft 12 engages the outer end of the collar 34. By tightening the nut 37, the

collar 34 is pressed into engagement with the bearing 32, and the collar 35 is drawn into engagement with the bearing 33'. I

The axial travel of lubricant along the shaft 12 is controlled at several locations by the provision of a series of seals. The passage of lubricant Ieftwardly from the bearing 32 is prevented along the inner diameter of the collar 34 by an O-ring 39 carried in an annular groove 40 of the shaft 12. A seal 41 pressed into an annular recess 42- in housing member 20 engages the outer diameter of collar 34. In

similar fashion seals

43, 44 carried respectively by the

housing members

21, 22 engage the shaft 12.

A quanitity of lubricant, not shown, is normally maintained within the chamber 23 to lubricate the pinion 28 and the gear 29. This lubricant also serves to lubricate the bearing 32. Lubricant for the bearing 33 is carried in a chamber defined by a cover 46 secured to housing member 21. A grease fitting 47 is carried by the cover 46 to admit lubricant to the chamber 45.

The eccentric 13 comprises an inner member 48 secured to the shaft 12. A square key 49 is interposed between the shaft 12 and the inner member to prevent relative rotation. The inner member has a circular periphery which is eccentric with the shaft 12. An annular outer member 50 is journaled rotatably on the inner member 48 by means of a roller bearing 51.

y The inner member 48 carries a grease fitting 52. A first lubricant passage 53 extends inwardly from the fitting 52 to the shaft 12. An axial groove 54 in shaft 12 communicates with the first passage 53 and with a second lubricant passage 55. Second passage 55 is provided to carry lubricant radially outwardly from the groove 54 to the bearing 51.

The transmission mechanism disposed in chamber 24 is best seen by referring to FIGS. 3 and 4 in conjunction with FIG. 1. The linkage means 15 may be seen to comprise a yolke 56 integrally formed with the outer eccentric member 50. The yoke 56 comprises left and

right legs

57, 58 having aligned openings formed therethrough to accommodate a pin 59. The pin 59 pivots within a pair of roller bearings 60 journaled in an aperture formed in the rocker arm 14. The pin 59 and the bearing 60 thereby provide a pivotal connection between the linkage means 15 and the rocker arm 14. As is best seen in FIG. 4, the bearings 60 are lubricated by means of a grease passage 61 which communicates with a grease fitting 62 carried by the rocker arm 14.

Referring primarily to FIG. 3, it will be seen that the pivot shaft 16 has a threaded aperture 63 formed coaxially within its left and right ends. Cap screws 64 extend through left and

right housing members

20, 21 and into the threaded apertures 63. An annular flanged insert 65 is positioned within an opening 66 in right housing member 21 to reduce the size of the opening 66 to a size which will accommodate one of the cap screws 64. When the cap screws 64 are tightened, the shaft 16 is securely held by the left and

right housing members

20, 21.

A pair of

roller bearings

67, 68 rotatably mount the rocker arm 14 about the shaft 16. The first or lower leg 17 of the rocker arm 14 terminates in a downwardly opening yoke 69. Aligned openings are formed in the yoke 69 to accommodate a drive pin 70. The drive pin 70 is restrained from axial movement by means of a locking pin 71. Thelocking pin 71 press fits into a cyliridrical opening 72 in the yoke 69, and into a groove 73 formed in the pin 70. A square bearing block 74 is carried by the pin 70. As will be explained later in greater detail, the bearing block 74 is part of a connection means provided to drive the mower sickle.

The second or upper leg 18 of the rocker arm has a threaded opening formed therein. The counterweight 19 has a large recess 76 formed therein to the upper end of the leg 18. An aperture 77 aligned with the threaded aperture extends upwardly through the counterweight 19. A cap screw 78 extends through the aperture 77 and threads into the threaded aperture 75. The head 79 of the cap screw 78 engages a recessed shoulder 80 formed within the aperture'77. By this arrangement, the counterweight 19 may be pulled downwardly over the leg 18 by tightening the cap screw 78. A set screw 81 is positional within a threaded aperture 82 which extends laterally of the aperture 77. The set screw 81 engages the cap screw 78 to lock the cap screw securely in position. The upper end of the chamber 24 adjacent the eccentric is closed by an eccentric cover 83, as best seen in FIG. 1. The lower end of the chamber 24 is provided with an opening 84 formed through the right housing member 21. The lower leg 17 and the yoke 69 of the rocker arm 14 extends through the opening 84. v

As was previously mentioned, the lower leg 17 of the rocker arm 14 drives a sickle. Referring to FIG. 6, a sickle 85 is seen to comprise a sickle bar 86 to which are secured aplurality of sickle sections 87 and a sickle head 88. The sickle 85 is carried for reciprocation by a cutter bar assembly including a support bar 89 which mounts a plurality of guards 90. Reciprocation of the sickle is limited to a planar translatory movement during which the sickle sections 87 cooperate with ledger plates (not shown) carried by the guards 90 to provide a cutting action.

As may be seen in the motion diagram of FIG. 5, the lower leg 17 of rocker arm 14 transcribes an arcuate motion during the course of its oscillation. The arcuate line 91 represents the path of motion of the drive pin 70. However, the sickle 85 which is driven from the leg 17 is limited to a planar translatory movement as represented by the line 92. In order to translate the arcuate motion of the rocker arm into a translatory planar motion, a connection means is provided including the bearing block 74. The sickle head 88 includes a cooperating, vertically disposed, open ended slot 93 which slip fits over the bearing block 74. By this arrangement, as seen in FIG. 5, the bearing block 74 moves relative to the slot '93 during its arcuate travel, whereby the sickle head 88 is not deflected by the rocker arm during reciprocation.

Although the foregoing description is necesarily of a detailed character, in order that the invention may be set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that various rearrangements of parts and modification of detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

1. A power driven reciprocating cutter comrising:

a. a reciprocable sickle movable back and forth along a straight-line path;

b. a rocker arm positioned to one side of said path and pivotally mounted for oscillating arcuate movement about a pivot axis;

0. drive means adapted for connection to a source of rotary motion and drivingly connected to said rocker arm to oscillate said rocker arm about said pivot axis between first and second extreme positions, which positions establish the stroke of said rocker arm;

d. said rocker arm including a pair of legs extending in opposite directions from said pivot axis;

e. one of said legs extending toward said sickle in a direction substantially perpendicular to said straight-line path when said rocker arm is near the center of its stroke;

f. a counterweight carried by the other of saidlegs;

g. connection means establishing a sliding driving connection between said one leg and said sickle and being operative to effect a positive driving movement of said sickle along said straight-line path without transmitting forces to said sickle transversely of said straight-line path; and,

h. said connection means including a driving member carried by said one leg for arcuate movement with said rocker arm, and a head carried on said sickle and slidably receiving said driving member.

2. The power driven cutter of claim 1 wherein said head has a pair of parallel spaced surfaces formed thereon which slidably engage said driving member therebetween.

3. The power driven cutter of claim 2 wherein said surfaces extend in planes substantially perpendicular to said straight-line path.

4. A power driven mowing machine comprising:

a. a reciprocable sickle;

b. a counterbalanced transmission comprising:

i. a housing structure;

ii. a drive shaft rotatably carried by said housing structure and adapted for connection to a sourc of rotary motion;

iii. a rocker arm pivotally carried by said housing structure and comprising a pair of legs extending in opposite directions from the pivot axis of said rocker arm;

iv. oscillating drive means drivingly coupling said drive shaft to said rocker arm to oscillate said rocker arm about said pivot axis in response to rotation of said drive shaft;

v. a counterweight carried by one of said legs for oscillating arcuate movement with said rocker arm;

0. connection means establishing a positive driving connection between said sickle and the other of said legs and being operative to transform the arcuate oscillatory'movement of said other leg into straight-line reciprocatory sickle drive motion;

d. said connection means including a driving member carried by said rocker arm and a slotted head carried by said sickle, said driving member being slidably received by said slotted head to establish a sliding driving connection between said rocker arm and said sickle, which connection is operative to transmit driving forces to said sickle substantially only in directions paralleling the straight line reciprocation path of said sickle, whereby substantially no forces are transmitted to said sickle which tend to deflect the sickle laterally of its reciprocation path during reciprocation.

5. A reciprocating cutter comprising:

a. a reciprocable s'ickle movable back and forth along a straight-line path;

b. a rocker arm pivotally mounted to one side of said path and having a pair of legs extending in opposite directions from the pivot axis of said rocker arm, one of said legs extending toward said sickle and the other of said legs extending away from said sickle;

c. drive means for oscillating said rocker arm through an arcuate stroke about said pivot axis;

d. a counterweight carried on said other leg;

e. connection means establishing a sliding connection between said one leg and said sickle, which connection is operative to transmit driving forces only in directions paralleling said straight line path to reciprocate said sickle as said rocker arm oscillates; and,

f. said connection means including a driving member carried by said one leg for arcuate movement with said rocker arm, and a head carried on said sickle and slidably receiving said driving member.

6. A reciprocating cutter comprising:

a. a reciprocable sickle movable back and forth along a straight-line path;

b. counterbalanced transmission means adapted for connection to a source of rotary drive motion and operative to transform rotary drive motion into oscillating motion along an arcuate path;

0. said transmission means including:

i. a housing structure;

ii. a drive shaft rotatably carried by said housing structure and adapted for connection to a source of rotary motion;

iii. an eccentric driven from said drive shaft;

iv. a rocker arm pivotally carried by said housing structure and comprising first and second legs extending in opposed directions from the pivot axis of said rocker arm;

v. linkage means connecting said rocker arm to said eccentric such that rotation of said drive shaft will operate said eccentric and will oscillate said rocker arm about said pivot axis;

vi. a counterweight carried by said second leg for movement therewith; and, i

d. connection means establishing a positive drive connection between said one leg and said sickle and being operative to transform said oscillating arcuate motion along saidarcuate path to straightline sickle reciprocating motion along said straightline path, said connection means including a driving member carried by said one leg for arcuate movement with said rocker arm, and a head carried on said sickle and slidably receiving said driving member whereby the connection established between said transmission means and said sickle is operative to transmit driving forces only in directions paralleling said straight-line path.

7. The reciprocating cutter of claim 6 wherein the interconnection of said linkage means and said rocker arm is located intermediate said pivot axis and the connection of said first leg to the sickle.

8. The mowing machineof claim 6 additionally including a hydraulic motor drivingly connected to said drive shaft.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,796,104 Dated March 12, 1974;

William E. Templeton Inventor(s) 1 I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 38, delete "sahft" and substitute Column 3, line 6l, after the word "to" insert accommodate 7 Column 1,51ine 48', delete "comr-i'sing" and substitute comprising Signed and sealed this 13th day of Augustl9'7h.

(SEAL) Attest:

McCOY 1Y1. GIBSON, JR. v C. MARSHALL DANN Attesting Officer Commissioner of Patents fQRM PO-IQSQ (1 uscoMM-oc cove-P69

Claims

1. A power driven reciprocating cutter comrising: a. a reciprocable sickle movable back and forth along a straight-line path; b. a rocker arm positioned to one side of said path and pivotally mounted for oscillating arcuate movement about a pivot axis; c. drive means adapted for connection to a source of rotary motion and drivingly connected to said rocker arm to oscillate said rocker arm about said pivot axis between first and second extreme positions, which positions establish the stroke of said rocker arm; d. said rocker arm including a pair of legs extending in opposite directions from said pivot axis; e. one of said legs extending toward said sickle in a direction substantially perpendicular to said straight-line path when said rocker arm is near the center of its stroke; f. a counterweight carried by the other of said legs; g. connection means establishing a sliding driving connection between said one leg and said sickle and being operative to effect a positive driving movement of said sickle along said straight-line path without transmitting forces to said sickle transversely of said straight-line path; and, h. said connection means including a driving member carried by said one leg for arcuate movement with said rocker arm, and a head carried on said sickle and slidably receiving said driving member.

4. A power driven mowing machine comprising: a. a reciprocable sickle; b. a counterbalanced transmission comprising: i. a housing structure; ii. a drive shaft rotatably carried by said housing structure and adapted for connection to a source of rotary motion; iii. a rocker arm pivotally carried by said housing structure and comprising a pair of legs extending in opposite directions from the pivot axis of said rocker arm; iv. oscillating drive means drivingly coupling said drive shaft to said rocker arm to oscillate said rocker arm about said pivot axis in response to rotation of said drive shaft; v. a counterweight carried by one of said legs for oscillating arcuate movement with said rocker arm; c. connection means establishing a positive driving connection between said sickle and the other of said legs and being operative to transform the arcuate oscillatory movement of said other leg into straight-line reciprocatory sickle drive motion; d. said connection means including a driving member carried by said rocker arm and a slotted head carried by said sickle, said driving member being slidably received by said slotted head to establish a sliding driving connection between said rocker arm and said sickle, which connection is operative to transmit driving forces to said sickle substantially only in directions paralleling the straight line reciprocation path of said sickle, whereby substantially no forces are transmitted to said sickle which tend to deflect the sickle laterally of its reciprocation path during reciprocation.

5. A reciprocating cutter comprising: a. a reciprocable sickle movable back and forth along a straight-line path; b. a rocker arm pivotally mounted to one side of said path and having a pair of legs extending in opposite directions from the pivot axis of said rocker arm, one of said legs extending toward said sickle and the other of said legs extending away from said sickle; c. drive means for oscillating said rocker arm through an arcuate stroke about said pivot axis; d. a counterweight carried on said other leg; e. connection means establishing a sliding connection between said one leg and said sickle, which connection is operative to transmit driving forces only in directions paralleling said straight line path to reciprocate said sickle as said rocker arm oscillates; and, f. said connection means including a driving member carried by said one leg for arcuate movement with said rocker arm, and a head carried on said sickle and slidably receiving said driving member.

6. A reciprocating cutter comprising: a. a reciprocable sickle movable back and forth along a straight-line path; b. counterbalanced transmission means adapted for connection to a source of rotary drive motion and operative to transform rotary drive motion into oscillating motion along an arcuate path; c. said transmission means including: i. a housing structure; ii. a drive shaft rotatably carried by said housing structure and adapted for connection to a source of rotary motion; iii. an eccentric driven from said drive shaft; iv. a rocker arm pivotally carried by said housing structure and comprising first and second legs extending in opposed directions from the pivot axis of said rocker arm; v. linkage means connecting said rocker arm to said eccentric such that rotation of said drive shaft will operate said eccentric and will oscillate said rocker arm about said pivot axis; vi. a counterweight carried by said second leg for movement therewith; and, d. connection means establishing a positive drive connection between said one leg and said sickle and being operative to transform said oscillating arcuate motion along said arcuate path to straight-line sickle reciprocating motion along said straight-line path, said connection means including a driving member carried by said one leg for arcuate movement with said rocker arm, and a head carried on said sickle and slidably receiving said driving member whereby the connection established between said transmission means and said sickle is operative to transmit driving forces only in directions paralleling said straight-line path.

8. The mowing machine of claim 6 additionally including a hydraulic motor drivingly connected to said drive shaft.