CA1119005A - Two-speed forward and reverse self-propel system for walk-behind mowers - Google Patents
Two-speed forward and reverse self-propel system for walk-behind mowersInfo
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- CA1119005A CA1119005A CA000368820A CA368820A CA1119005A CA 1119005 A CA1119005 A CA 1119005A CA 000368820 A CA000368820 A CA 000368820A CA 368820 A CA368820 A CA 368820A CA 1119005 A CA1119005 A CA 1119005A
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- drive
- wheel
- drive shaft
- gears
- shaft
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- 230000002441 reversible effect Effects 0.000 title claims description 28
- 230000005540 biological transmission Effects 0.000 claims abstract description 48
- 230000008093 supporting effect Effects 0.000 claims abstract description 3
- 230000033001 locomotion Effects 0.000 claims description 52
- 230000007935 neutral effect Effects 0.000 claims description 16
- 150000001875 compounds Chemical class 0.000 description 12
- 230000006835 compression Effects 0.000 description 5
- 238000007906 compression Methods 0.000 description 5
- 238000010276 construction Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003534 oscillatory effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
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Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed herein is a plurality of wheels for supporting the blade housing, a blade mounted for rotation within the blade housing, a prime mover supported on the housing, a drive shaft mounted for rotation relative to the housing and adapted for connection to one of the wheels for driving thereof, a transmission mounted on the housing and including a rotatable input shaft drivingly connected to the prime mover, a pair of gears mounted co-axially with the drive shaft, gear teeth for connecting the input shaft to the pair of gears so as to drive one of the gears at a first speed and so as to drive the other gear at a second speed, and a clutch for alternatively and selectively connecting the gears to the drive shaft for driving the drive shaft, which clutch includes a shiftable element drivingly mounted on the drive shaft between the pair of gears and selectively and alternatively connectable to the gears.
Disclosed herein is a plurality of wheels for supporting the blade housing, a blade mounted for rotation within the blade housing, a prime mover supported on the housing, a drive shaft mounted for rotation relative to the housing and adapted for connection to one of the wheels for driving thereof, a transmission mounted on the housing and including a rotatable input shaft drivingly connected to the prime mover, a pair of gears mounted co-axially with the drive shaft, gear teeth for connecting the input shaft to the pair of gears so as to drive one of the gears at a first speed and so as to drive the other gear at a second speed, and a clutch for alternatively and selectively connecting the gears to the drive shaft for driving the drive shaft, which clutch includes a shiftable element drivingly mounted on the drive shaft between the pair of gears and selectively and alternatively connectable to the gears.
Description
TITLE
"Two-Speed Forward and Reverse Self-Propel System for Walk-Behind Mowers"
INVENTORS
William Fuelling, Jr. and Richard Heismann RELATED APPLICATION
This application is a division of Canadian applica-tion Serial No. 321,999, filed February 21, 1979.
BACKGROUND OF THE INVENTION
The invention relates generally to selr-propelled lawn mowers and more particularly to multi-speed transmissions for self-propelled lawn mowers having forward and reverse drives and to means for shifting such transmissions.
Self-propelled lawn mowers typically are driven by a transmission connected to the cutter blade drive shaft.
The transmission generally provides for rotation of the mower drive shaft in only one direction such that the lawn mower is self-propelled in only one direction. Additionally, common methods of providing a self-propel system for a lawn mower require shifting of the transmission with the transmission under load and the power being directly connected to the drive wheels during shifting. Such arrangements cause loading of the transmission components and drive shaft during shifting.
Canadian Patent Application Serial No. 313,126 filed October 11, 1978 and assigned to the assignee of the present invention discloses a transmission for a self-propelled power mower including a drive shaft having drive means en g ag e a b le with drive wheels to thereby drive the drive wheels of the mower. The drive means include a low-speed drive .........
~~-~ member mounted on the drive shaft for common .
rotation therewith and for engaging a drive wheel and a high-speed arive member having an outer diameter greater than the diameter of the low-speed drive member. The high-speed drive member is splined on the low-speed drive member and is selectively and alternatively moved into engagement with the ~ drive wheel.
United States Patent No. 2,947,132, issued August 2, 1960 to Shaw discloses a transmission for a power mower or the like including a drive shaft which is drivingly connected to a prime mover and ' ' . '~ '.'.` i ~i a pair of the mower wheels selectively movable into frictional engagement with the drive shaft to drive the mower.
United States Patent No. 2,962,854 issued . , ~".
December 6, 1960 to Jepson discloses a two-speed drive gear having concentric rings of gear teeth . . .-. - . . .
and a driven gear which is connected to a wheel-engageable drive shaft and can be moved axially to : mesh with either of the drive gear rings for varying the mower speed.
U.S. Patent No. 2,736,389, issued February 28, 1956, U.S. Patent No. 3,433,002, issued March 18, 1969 and U.S. Patent No. 3,035,385, issued May 22, 1962 each disclose another alternative means for driving a self-propelled lawn mower.
SUMMARY OF THE INVENTION
.
The invention provides a self-propelled lawn mower including a blade housing supported on a .~ .
11~9~005 a plurality of wheels, a blade mounted for rotation within the blade housing, a prime mover supported on the housing, a drive shaft mounted for rotation relative to the housing and adapted for connection to one of the wheels for driving thereof, transmission means mounted on the housing and includes a rotatable input shaft drivingly connected to the prime mover, a pair of gears mounted co-axially with the drive shaft, means for connecting the input shaft to the pair of gears so as to drive one of the gears at a first speed and so as to drive the other gear at a second speed, and means for alternatively and selectively connecting the gears to the drive shaft for driving the drive shaft, which means includes a shiftable element drivingly mounted on the drive shaft between the pair of gears and selectively and alternatively connectable to the gears.
In one embodiment of the invention, the pair of gears are each supported on the drive shaft and are rotatable on the drive shaft.
In one embodiment in accordance with the invention, the lawn mower also includes a friction driving roll mounted on the drive shaft for engaging the periphery of the one wheel, together with means on the housing mounting the one wheel for movement to and from engagement with the friction driving roll, a guiding handle connected to the housing, and means movably mounted on the guiding handle and connected to the means mounting the one wheel for moving the one wheel to and from engagement with the friction driving roll.
~1~9005 In one embodiment in accordance with the invention, the means for connecting the input shaft to the pair of gears includes a second rotatable shaft drivingly connected to the pair of gears, a second pair of gears driven by the input shaft, and means for selectively and alternatively drivingly connecting the second pair of gears to the second rotatable shaft whereby the drive shaft can be reversibly rotated.
In one embodiment of the invention, the lawn mower further includes means operable between the drive shaft and one of the wheels for selectively drivingly engaging the drive shaft to the one wheel, and means connected to the shiftable element and to the means for selectively drivingly engaging the drive shaft to the one wheel for precluding shifting of the transmission when the one wheel is drivingly engaged by the shaft.
In one embodiment of the invention, the drive shaft includes a friction driving roll and the lawn mower also includes means on the housing for mounting the one drive wheel for movement to and from engagement with the friction driving roll, and means for precluding shifting the transmission until disengagement of the one drive wheel and the friction driving roll, which means for precluding shifting being connected to the means for mounting the one drive wheel.
Other features and advantages of the embodi-ments of the invention will become apparent to those :1119V05 ~
skilled in the art upon reviewing the following detailed description, the drawings and the appended claims.
1 BRIEF DESCRIPTION OF THE DRAWIilGS
Fig. 1 is a side elevational view of a r. mower equipped with a transmission and embodying the . ~, ~:~ .i invention.
~~ Fig. 2 is an enlarged fragmentary detailed view in perspective showing the mower drive transmission and the mounting of one of the mower wheels.
Fig. 3 is an enlarged fragmentary side ,- elevational view of the drive wheel mounting and showing the drive wheel disengaged from the drive . ..~. .. :... ~
: roll.
Fig. 4 is a view similar to Fig. 3 but showing the drive wheel in the forward drive position ~ ,s engaged with the drive roll.
Fig. 5 is a cross-section view taken along ~r'.
line 5-5 in Fig. 4.
Fig. 6 is a fragmentary detail view in side -:: elevation of the upper end of the mower guiding handle and showing the control handle mounted for movement relative to the guiding handle.
Fig. 7 is an enlarged plan view of the gear assembly of the mower transmission.
Fig. 8 is an enlarged cross-section plan view of the transmission housing.
Fig. 9 is an exploded view of the trans-;; mission components shown in Fig. 8.
Before explaining at least one embodiment of the invention in detail, it is to be understood that ~ .
,,, 111~3005 r the invention is not limited in its application to ~:` the details of construction and the arrangements of the components set forth in the following description pr illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways.
Also, it is to be understood that the phraseology and terminology employed herein is for the purposes of description and should not be regarded as limiting.
DESC~IPTION OF THE PREFERRED EMBODIME~IT
Illustrated in the drawings is a self-propelled lawn mower 10 including a prime mover 12, such as an ~~`' internal combustion engine or an electric motor, ,i.r . ~ ~ , --~ partially covered by a shroud 14 and supported on a frame including a blade housing 16. Drivingly connected to the prime mover 12 is an engine drive shaft 17 :: . which drives a rotary cutter biade 18 located inside .. .. .
` ` the blade housing 16. The mower 10 is supported for ... -: .
. travel along the ground by a pair of front wheels 20 . .~ .
(one shown) and a pair of rear wheels 21 (one shown) ~=~ carried on an axle 24 supported rearwardly of the ....
blade housing 16 as described in more detail below.
~; The mower 10 is guided by a guiding handle 23 connected to and extending rearwardly from the blade housing 16.
The mower 10 is powered by a drive mechanism which is operable to selectively connect the prime mover ` 12 in driving engagement with at least one of the rear wheels 21. In the specific construction illustrated, the ... vertical drive shaft 17 is provided with a bevel gear 19 thereon and the drive mechanism includes an input shaft 26 having a bevel gear 25 at one end meshing with the bevel gear 19, whereby the vertical drive shaft 17 ~IL11900s ~
. rotatably drives the inPut shaft 26. In al~ernative .:.
embodiments the input shaft 25 could also be driven by ~t~ driving means such as by a worm and worm gear assembly.
The input shaft 26 is drivingly connected to a transverse drive shaft 28 by a transmission means 30 to be described below. The drive shaft 28 is rotatably supported and includes at least one friction drive roll 34 located on at least one end portion of the drive shaft 28 for selectively engaging the outer periphery of the rear wheels 21 for driving the mower 10.
The transmission means 30 includes a housing 35 (Fig. 2) comprising a lower housing member =~
36 and an upper housing member 38. The drive shaft 28 extends through the housing 35 and is rotatably supported by bearings 40 supported between the side walls of the upper and Lower housing members 36 and 38. Referring to Fig. 7, the transmission is shown ~ . . .
as also including a second rotatable shaft 42 supported ;.......
-~.~ within the housing and in parallel spaced apart relation with respect to the drive shaft 28. The opposite -~-~ ends of the rotatable shaft 42 are rotatably supported . .
by bearings 44 (Fig. 2) supported between the side . ~ walls of the upper and lower housing members 36 and~ .
38. The input shaft 26 extends through the front wall of the housing and is perpendicular to the drive shaft 28 and the second rotatable shaft 42. The end of the input shaft extending into the transmission ~ housing 35 supports a bevel gear 46 in meshing engage-- . ment with two spaced bevel gears 48 supported on the rotatable shaft 42. The two spaced bevel gears 48 OOS ~
are each freely rotatable on the rotatable shaft 42 and are driven in opposite rotational directions by the bevel gear 46 secured to the end of the input shaft 26.
A forward and reverse shift dog S0 is supported on the rotatable shaft 42 between the spaced bevel gears 48 and is splined to the rotatable shaft 42 for rotation therewith and for slidable movement along the rotatable shaft 42 between the bevel gears. The forward and reverse shift dog 50 includes projecting lugs 52 which are selectively and alternatively receivable in notches 54 in the ` opposed faces of the spaced bevel gears 48 upon slidable movement of the shift dog 50 along the rotatable shaft 42 between the bevel gears 48 such - - that the bevel gears 48 and the shift dog 50 transmit . . .
;- rotation of the input shaft 26 to the rotatable shaft -..: . .
~ 42. Since the bevel gears 48 are driven in opposite . A .~. ~ .
directions, the direction of rotation of the second.
;-= 20 rotatable shaft 42 can be changed by moving the shift ~- dog 50 from engagement with one of the bevel gears 48 . .
to engagement with the other gear 48. A pair of gears 56 and 58 are respectively keyed to the opposite ends of the rotatable shaft 42, for rotation therewith, the gear 56 of the pair of gears being larger and having a greater number of gear teeth than the other gear 58.
The drive shaft 28 supports a pair of gears 60 and 62 in spaced apart relation, the gear 60 having a larger diameter than gear 62 and meshing with the smaller gear 58 driven by the rotatable shaft 42.
.
~a ~119~05 . The other gear 62 meshes with gear 56 driven by the rotatable shaft 42. Each of the gears 60 and 62 is freely rotatable with respect to the drive shaft 28. An axially slidable shift dog 64 is disposed between the gears 60 and 62 and is splined to the drive shaft 28 for rotation with the drive . shaft 28 but is axially slidably movable along the drive shaft 28 between the gears 60 and 62. The shift dog 64 includes projecting lugs 66 which are selectively and alternatively engageable with notches 68 in the . faces of the opposed gears 60 and 62 whereby rotation ; ~ of one of the gears 60 or 62 is transmitted through ,~
~ the shift dog 64 to the drive shaft 28 for driving .... ...
.~ the drive shaft 28.
: 15 The larger gear 60 is shown as meshing . with a smaller gear 58 on the rotatable shaft 42 and is . - ~
,;~ ~r.;; ~
~~- accordingly driven at a lower rotational speed than . ~, ^ gear 62 meshing with the larger gear 56 on the rotatable shaft 42. Accordingly, shifting of the 'c~ 20 shift dog 64 from engagement with gear 60 into engage- .
- ment with gear 62 will cause an increase in the speed of rotation of the drive shaft 28. As a corollary, movement of the shift dog 64 from engagement with gear 62 to engagement with gear 60 will cause a decrease in the speed of rotation of the drive shaft 28.
Referring to Figs. 7 through 9, movement of the shift dog S0 is controlled by a forward and reverse shifter yoke 70 which is received in an annular groove 72 surrounding the circumference of the shift dog 50. The yoke 70 is attached to a forward and reverse shifter bar 74, the shifter bar 74 being ~ , ~llg~o5 -;
: slidably movable parallel to the rotatable shaft 42 and having its opposite ends supported on two spaced shelves 75 integral with the upper housing member 38 and on opposite sides of the shift dog 50. The shifter yoke 70 extends downwardly between the spaced shelves 75 from the shifter bar 74 to engage the shifter dog 50. The shelves are spaced to define a rectangular opening therebetween receiving the yoke 70 therein and permitting movement of the shifter yoke 70 in the direction of the axis of the shaft 42.
Referring to Figs. 8 and 9, movement of the shifter , ~ bar 74 and the shifter yoke 70 is controlled by a shift lever 76, the shift lever 76 being pivotally attached intermediate its opposite ends by a pivot pin 78 extending upwardly from the upper housing member 38. One of the ends of the shift lever 76 includes ` an opening 80 therethrough receiving a pin 82 extending .. - upwardly from the shifter bar 74. The opening 80 is . , .~ .
~ p larger than the pin 82 to permit overtravel of the . .. ~ -s-w~.. --; 20 shift lever 76 with respect to the shifter bar 74.
One end of an inner wire 84 of a push-pull cable 86 (Fig. 2) is attached to the end of shift lever 76 opposite the end housing opening 80 for causing pivotal movement of the shift lever 76. The push-pull cable 86 is supported by a projection 90 extending . upwardly from the upper housing member 38 and is : retained therein by a pair of nuts 92 and 94.
A forward and reverse detent lever 96 is operable with the shifter bar 74 to selectively maintain the shift dog 50 in engagement with the selected one of the bevel gears48. The detent lever 1119~05 ~
---~ 96 includes a pair of angularly disposed lever arms 98 and 100 and is pivotally attached to the upper housing member 38 intermediate the arms98 and 100 by a plvot pin 99. The lever arm 98 includes a slot 102 for receiving a pin 104 extending upwardly from the shifter bar 74. A compression spring 106 bears against the end of the other lever arm 100 and is maintained in compression between the end of the lever arm 100 and the upper housing member 38. The compression spring 106 releasably maintains the detent lever 96 in either the solid line Dosition shown in Fig. 8 or the dashed line position. When the detent ; lever 96 is in the solid line position shown in Fig.
8, the lever arm 98 of detent lever 96 maintains the shifter bar 74 in the solid line position and the shift dog 50 will be held in engagement with one of the bevel gears 48 by the yoke 70 which extends downwardly from the shifter bar 74. When the detent .
~ lever 96 is in the dashed line position shown in Fig~. 8, :,~
the lever arm 98 of detent lever 96 maintains the shifter bar 74 in the dashed line position and the shift dog 50 will be held in engagement with the other bevel gear 48.
Movement of the shift dog 64 between selective and alternative engagement with the gears 60 and 62 is controlled by a speed selector shifter yoke 108 . which is received in an annular groove 110 surrounding ., .
the circumference of the shift dog 64. The yoke 108 is attached to and e~tends downwardly from a speed selector shifter bar 112, the shifter bar 112 being slidably movable parallel to the drive shaft 28 and 1119005 ~
. having its opposite ends supported on two spaced shelves 114 integral with the upper housing member 38 and on opposite sides of the shift dog 64. The shelves 114 define an opening therebetween for receiving the yoke 108 and for permitting movement of the yoke . 108 in the direction of the axis of the drive shaft 28.
.. ..
...~.
~ ~ The shifter yoke 108 extends downwardly between the .: . ..;
spaced shelves 114 from the shifter bar 112 to engage the shift dog 64. Movement of the shifter bar 112 and t~he shifter yoke 108 is controlled by a speed selector shift lever 116 pivotally attached at one of its ends to the upper housing member 38 by the pivot ... ~ ~
~ pin 78. The other end of the shift lever 116 projects . . ,~
rearwardly from the transmission, and its projecting end forms a manually operable handle for shifting the transmission between low and high speeds. The shift ~ lever 116 includes a slot 118 intermediate its : ~ opposite ends for receiving a pin 120 extending from ~ the upper surface of the shifter bar 112. Lateral '~;~
-~.-~- 20 movement of the projecting end of the shift lever 116 - will result in lateral movement of the shifter bar 112 and similar movement of the yoke 108 and shift dog 64.
The shifter bar 112 is provided with a pair ;
of notches 122 in one of its edges and a detent pin 126 is slidably housed in a bore 128 in the upper housing member 38 and is biased into engagement with the notches 122 by a compression spring 130 therebv releasably restraining the shifter bar 112 and yoke 108 against movement.
The structure described above for shifting the transmission from forward to reverse is independent of ~ .
lll9(~0S (-- the high and low speed shifting means. Accordingly, ... .
the transmission can be shifted from between forward and reverse when the transmission is in either the high or low speed driving modes. Similarly, the transmission can be shifted between high and low speeds when the transmission is in either forward or reverse.
Referring to Figs. 2-3, means are provided for moving the drive shaft 28 and the rear wheels 21 relative to each other between a drive position wherein the friction driving roll 34 frictionally engages the outer periphery of one of the rear wheels 21 and a non-driving position wherein the friction driving roll 34 .. .,--.
is disengaged from the rear wheels 21. More specifically, : the wheels 21 are rotatable with respect to the sup-porting axle 24 which is carried by levers 132 (one shown) pivotably mounted by a pivot 138 on arms 136 (one : shown~ ofa yoke 140. The arm~ ].36 of the yoke 1~0 are fixedly supported from the blade housing 16. The levers 132 project upwardly from the arms 136 and accommodate fore and aft movement of the axle 24 and the rear wheels 21 relative to the drive shaft 28 for respectively engaging the rear wheels 21 with the friction driving . . .
. ~ roll 34 and disengaging the rear wheels 21 from the ~~~ friction driving roll 34. At least one of the levers ; . ,.
132 includes a downwardly extending lever arm portion . . . _ _ .
141, and a tension spring 142 is connected between the ;~ ~ lever arm portion 141 and the blade housing 16 to urge the rear wheels 21 rearwardly with respect to blade housing 16 and toward the disengaged position.
Movement of the rear wheels 21 between the position where they are engaged with friction driving . ~ .
1~19005 ~
.. -` roll 34 and the position where they are disengaged from the friction driving roll 34 is effected by a control handle 143 (Figs. l and 6) mounted on the guiding handle 23 and capable of limited independent movement with respect to the guiding handle 23. An actuator rod 152 is operatively connected at one of its ends to the control handle 143 and is connected at its lower end to the wheel axle 24 through a linkage arrangement.
Oscillatory movement of the control handle 143 with respect to the guiding handle 23 is used to transmit motion through the actuator rod 152. Thus, .. ...
movement of the control handle 143 from the full line neutral position shown in Fig. 6 to the broken line forward position causes the actuator rod 152 to extend downwardly while movement of the control handle 143 `-~ from the full line neutral ~osition to the dashed line reverse position causes the actuator rod 152 to move upwardly.
~*~ 20 Referring to Figs. 3-5, at its lower end the actuator rod 152 is pivotally connected to the end of a lever arm 154 of a compound lever 156. The compound lever 156 is pivotally connected to the yoke arm 136 by a bolt 158 and further includes a lever arm 160 pivotally connected at 162 to a link 164.
~ Another link 166 is pivotally mounted at one end .-.:m............ directly on the axle 24 and its other end is connected . .
to the link 164.
To facilitate adjustment of the clearance between the wheel 21 and the drive roller 34 when the wheel 21 and drive roller 34 are disengaged, the link 164 is provided 1119~05 ~
~:~`~ with a longitudinal slot 174 (Fig. 5~ in its end opposite that connected to the lever arm 160, and the link 166 similarly includes a longitudinal slot 176 in its end opposite that pivotally mounted on axle 24. The links 164 and 166 are secured together by a bolt 178 extending through link 166 and received in the slot . 174 and by an integral tab 180 extending from the link 164 and received in the longitudinal slot 176.
Loosening the bolt 178 permits limited relative slidable movement of the links 164 and 166 for adjustment of the ~ clearance between the wheels 21 and the drive roller 34.
; ~ The shift lever 76 of the transmission 30 is ; ~ also connected to the control handle 143 of the mower such that--forward movement of the control handle 143 to its forward position shown in Fig. 6 causes the .. - shift lever 76 to pivot to its forward drive position ~.....
~ and rearward movement of the control handle 143 ~ .,~, . ..
past the neutral position causes shift lever 76 to pivot to its reverse driving position. To facilitate such connection of the control handle 143 to the shift ~,...
'c'`r,. lever 76 of the transmission 30, the compound lever 156 also includes a downwardly extending lever arm 168 = ..... , j-, .~
connected by pin 169 to an end of the inner wire 84 of the push-pull cable 86. The conduit of the push-pull 25 cable 86 adjacent the lever arm 168 is rigidly supported .
by a bracket 170 attached to the yoke arm 136.
When the control handle 143 is moved forwardly with respect to the guiding handle from the neutral ` :
driving position to the forward driving position, the actuator rod 152 is moved downwardly and the compound lever 156 and links 164 and 166 are moved to the position 11~91005 ~
:: X illustrated by the full line in Fig. 4, thereby pulling axle 24 forwardly toward a wheel engaging position, in which position the a~le 24 is advanced so that the periphery of wheel 21 engages the friction driving $oll 34. At the same time, the downwardly extending lever arm 168 will pull the inner wire 84 of the push-pull cable 86 causing pivotal movement of the shift lever 76 and thereby causing the transmission 30 to be shifted into the forward driving position.
- 10 Movement of the control handle 143 from the forward position to the neutral position effects an upward longitudinal advance of the actuator rod 152, ~;; thereby moving the compound lever 156 and the links 164 and 16~ toward the neutral position shown in Fig.
1. During pivotal movement of the lever 156 from the forward to neutral position, the links 164 and 166 . " .
- will be caused to move rearwardly toward the Position . ~ ..~ .
shown in Fig. 3 whereupon the axle 24 is caused to be moved toward the rearward neutral position.
Movement of the control handle 143 from the .: neutral position toward the reverse position causes rotation of the compound lever 156 and ~ovement of the links 164 and 166 to the position shown in phantom in Fig. 4. As in the shifting motion from neutral to forward, when the compound lever 156 is shifted from the neutral position to the reverse position, the rear axle 24 is pulled forwardly and wheels 21 and 22 engage friction drive rolls 34. At the same time, the downwardly extending lever arm 16~3 will move forwardly as viewed in Figs. 3 and 4 pushing on the inner wire 84 of the push-pull cable 86 thereby ..,... ~ ..
~19(~05 ~
..; =,;
- causing pivotal movement of the shift lever 76 of the transmission into a reverse driving position shown in solid lines in Fig. 8. Such movement of the lever 76 is assisted by a compression spring 171 ~Figs. 2 and 8) compressed between the end of the conduit 86 and the end of the lever 76.
One of the features of the invention is that the transmission 30 is shifted between the forward and reverse driving modes only when the drive wheel 21 is disengaged from the drive roll 34, and the trans-mission is precluded from shifting when the drive wheel 21 is in driving engagement with the drive roll 34.
....-..
- ~ Accordingly, the loads on-the gears of the transmission 30 are reduced before the transmission is shifted between the forward and reverse driving modes. More specifically, when the control handle 143 is in the : forward position shown in dashed lines in Fig. 6, _. the compound lever 156 is in the position shown in . ., ~
` ~ solid lines in Fig. 4 and the drive wheel 21 engages drive roll 34. The transmission shift lever 76 is also in the position shown in phantom in Fig. 8. When the control handle 143 is moved rearwardly toward the .... ,.. ,~, . .
neutral position, the actuator rod 152 causes pivotal movement of the lever 156 toward the solid line position shown in Fig. 3 thereby causing pivotal movement of lever 132 and rearward movement of the axle 24 and drive wheel 21 away from the drive roll 34. Movement of the control handle 143 toward the neutral position also causes the inner wire 84 of conduit 86 to move shift lever 76 from the forward position toward the the reverse position. However, the drive wheel 21 is .
r l~l9~0S
disengaged from driving roll 34 before the lever 76 begins to cause shifting movement of the shift dog 50 of the transmission because the opening 80 in the end of the lever arm 76 for engaging the pin 82 is larger than the pin 82 and permits initial lost motion of the lever 76 before lever 76 acts on pin 82 to cause shifting of the shift dog 50 of the transmission 30 toward the reverse driving position.
As the control handle 143 is moved toward the reverse position shown in Fig. 6, the actuator rod 152 pivots the compound lever 156 toward the position shown in dashed lines in Fig. 4. Such movement of the compound lever 156 will cause the lever arm 168 thereof to move forwardly pushing the inner wire 84 to the position shown in Fig. 8 and moving lever 76 to the solid line position shown in Fig, 8 : wherein the transmission 30 is in its reverse driving . . .
mode. The drive wheel 21 does not engage the drive . roll 34 until the completion of the shifting movement.
Accordingly, the shift lever 76 acts to cause shifting of transmission 30 into the reverse driving position before the drive wheel 21 is moved into driving engage-ment with drive roll 34.
When the control handle 143 is in its reverse driving position, the shift lever 76 assumes the position shown in solid lines in Fig. 8. ~Jhen the control handle 143 is moved from the reverse driving position to the - forward driving position, during initial movement of the compound lever 156 toward its neutral position, the links 164 and 166 and the return spring 142 cause immediate rearward movement of the drive wheel 21 awav .
~119005 ~
. ~ . Y . _.
-.. ` from the drive roll 34. Movement of the control handle 143 and consequent movement of the compound lever 156 also causes movement of the inner wire 84 of the push-pull cable 86 and movement of the shift lever 76. However, since the opening 80 in the . end of lever 76 permits relative lost motion between : the shift lever 76 and the pin 82 connected to the .; . ~
shift dog 50, the transmission does not begin to shift from the reverse to the forward drive position until the drive wheel 21 is disengaged from the drive roll 34.
Various of the features of the invention are set forth in the following claims.
. . . .
...~. ~
...... _ ' ffG'~.~
.'~, ~, , :-~
"Two-Speed Forward and Reverse Self-Propel System for Walk-Behind Mowers"
INVENTORS
William Fuelling, Jr. and Richard Heismann RELATED APPLICATION
This application is a division of Canadian applica-tion Serial No. 321,999, filed February 21, 1979.
BACKGROUND OF THE INVENTION
The invention relates generally to selr-propelled lawn mowers and more particularly to multi-speed transmissions for self-propelled lawn mowers having forward and reverse drives and to means for shifting such transmissions.
Self-propelled lawn mowers typically are driven by a transmission connected to the cutter blade drive shaft.
The transmission generally provides for rotation of the mower drive shaft in only one direction such that the lawn mower is self-propelled in only one direction. Additionally, common methods of providing a self-propel system for a lawn mower require shifting of the transmission with the transmission under load and the power being directly connected to the drive wheels during shifting. Such arrangements cause loading of the transmission components and drive shaft during shifting.
Canadian Patent Application Serial No. 313,126 filed October 11, 1978 and assigned to the assignee of the present invention discloses a transmission for a self-propelled power mower including a drive shaft having drive means en g ag e a b le with drive wheels to thereby drive the drive wheels of the mower. The drive means include a low-speed drive .........
~~-~ member mounted on the drive shaft for common .
rotation therewith and for engaging a drive wheel and a high-speed arive member having an outer diameter greater than the diameter of the low-speed drive member. The high-speed drive member is splined on the low-speed drive member and is selectively and alternatively moved into engagement with the ~ drive wheel.
United States Patent No. 2,947,132, issued August 2, 1960 to Shaw discloses a transmission for a power mower or the like including a drive shaft which is drivingly connected to a prime mover and ' ' . '~ '.'.` i ~i a pair of the mower wheels selectively movable into frictional engagement with the drive shaft to drive the mower.
United States Patent No. 2,962,854 issued . , ~".
December 6, 1960 to Jepson discloses a two-speed drive gear having concentric rings of gear teeth . . .-. - . . .
and a driven gear which is connected to a wheel-engageable drive shaft and can be moved axially to : mesh with either of the drive gear rings for varying the mower speed.
U.S. Patent No. 2,736,389, issued February 28, 1956, U.S. Patent No. 3,433,002, issued March 18, 1969 and U.S. Patent No. 3,035,385, issued May 22, 1962 each disclose another alternative means for driving a self-propelled lawn mower.
SUMMARY OF THE INVENTION
.
The invention provides a self-propelled lawn mower including a blade housing supported on a .~ .
11~9~005 a plurality of wheels, a blade mounted for rotation within the blade housing, a prime mover supported on the housing, a drive shaft mounted for rotation relative to the housing and adapted for connection to one of the wheels for driving thereof, transmission means mounted on the housing and includes a rotatable input shaft drivingly connected to the prime mover, a pair of gears mounted co-axially with the drive shaft, means for connecting the input shaft to the pair of gears so as to drive one of the gears at a first speed and so as to drive the other gear at a second speed, and means for alternatively and selectively connecting the gears to the drive shaft for driving the drive shaft, which means includes a shiftable element drivingly mounted on the drive shaft between the pair of gears and selectively and alternatively connectable to the gears.
In one embodiment of the invention, the pair of gears are each supported on the drive shaft and are rotatable on the drive shaft.
In one embodiment in accordance with the invention, the lawn mower also includes a friction driving roll mounted on the drive shaft for engaging the periphery of the one wheel, together with means on the housing mounting the one wheel for movement to and from engagement with the friction driving roll, a guiding handle connected to the housing, and means movably mounted on the guiding handle and connected to the means mounting the one wheel for moving the one wheel to and from engagement with the friction driving roll.
~1~9005 In one embodiment in accordance with the invention, the means for connecting the input shaft to the pair of gears includes a second rotatable shaft drivingly connected to the pair of gears, a second pair of gears driven by the input shaft, and means for selectively and alternatively drivingly connecting the second pair of gears to the second rotatable shaft whereby the drive shaft can be reversibly rotated.
In one embodiment of the invention, the lawn mower further includes means operable between the drive shaft and one of the wheels for selectively drivingly engaging the drive shaft to the one wheel, and means connected to the shiftable element and to the means for selectively drivingly engaging the drive shaft to the one wheel for precluding shifting of the transmission when the one wheel is drivingly engaged by the shaft.
In one embodiment of the invention, the drive shaft includes a friction driving roll and the lawn mower also includes means on the housing for mounting the one drive wheel for movement to and from engagement with the friction driving roll, and means for precluding shifting the transmission until disengagement of the one drive wheel and the friction driving roll, which means for precluding shifting being connected to the means for mounting the one drive wheel.
Other features and advantages of the embodi-ments of the invention will become apparent to those :1119V05 ~
skilled in the art upon reviewing the following detailed description, the drawings and the appended claims.
1 BRIEF DESCRIPTION OF THE DRAWIilGS
Fig. 1 is a side elevational view of a r. mower equipped with a transmission and embodying the . ~, ~:~ .i invention.
~~ Fig. 2 is an enlarged fragmentary detailed view in perspective showing the mower drive transmission and the mounting of one of the mower wheels.
Fig. 3 is an enlarged fragmentary side ,- elevational view of the drive wheel mounting and showing the drive wheel disengaged from the drive . ..~. .. :... ~
: roll.
Fig. 4 is a view similar to Fig. 3 but showing the drive wheel in the forward drive position ~ ,s engaged with the drive roll.
Fig. 5 is a cross-section view taken along ~r'.
line 5-5 in Fig. 4.
Fig. 6 is a fragmentary detail view in side -:: elevation of the upper end of the mower guiding handle and showing the control handle mounted for movement relative to the guiding handle.
Fig. 7 is an enlarged plan view of the gear assembly of the mower transmission.
Fig. 8 is an enlarged cross-section plan view of the transmission housing.
Fig. 9 is an exploded view of the trans-;; mission components shown in Fig. 8.
Before explaining at least one embodiment of the invention in detail, it is to be understood that ~ .
,,, 111~3005 r the invention is not limited in its application to ~:` the details of construction and the arrangements of the components set forth in the following description pr illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways.
Also, it is to be understood that the phraseology and terminology employed herein is for the purposes of description and should not be regarded as limiting.
DESC~IPTION OF THE PREFERRED EMBODIME~IT
Illustrated in the drawings is a self-propelled lawn mower 10 including a prime mover 12, such as an ~~`' internal combustion engine or an electric motor, ,i.r . ~ ~ , --~ partially covered by a shroud 14 and supported on a frame including a blade housing 16. Drivingly connected to the prime mover 12 is an engine drive shaft 17 :: . which drives a rotary cutter biade 18 located inside .. .. .
` ` the blade housing 16. The mower 10 is supported for ... -: .
. travel along the ground by a pair of front wheels 20 . .~ .
(one shown) and a pair of rear wheels 21 (one shown) ~=~ carried on an axle 24 supported rearwardly of the ....
blade housing 16 as described in more detail below.
~; The mower 10 is guided by a guiding handle 23 connected to and extending rearwardly from the blade housing 16.
The mower 10 is powered by a drive mechanism which is operable to selectively connect the prime mover ` 12 in driving engagement with at least one of the rear wheels 21. In the specific construction illustrated, the ... vertical drive shaft 17 is provided with a bevel gear 19 thereon and the drive mechanism includes an input shaft 26 having a bevel gear 25 at one end meshing with the bevel gear 19, whereby the vertical drive shaft 17 ~IL11900s ~
. rotatably drives the inPut shaft 26. In al~ernative .:.
embodiments the input shaft 25 could also be driven by ~t~ driving means such as by a worm and worm gear assembly.
The input shaft 26 is drivingly connected to a transverse drive shaft 28 by a transmission means 30 to be described below. The drive shaft 28 is rotatably supported and includes at least one friction drive roll 34 located on at least one end portion of the drive shaft 28 for selectively engaging the outer periphery of the rear wheels 21 for driving the mower 10.
The transmission means 30 includes a housing 35 (Fig. 2) comprising a lower housing member =~
36 and an upper housing member 38. The drive shaft 28 extends through the housing 35 and is rotatably supported by bearings 40 supported between the side walls of the upper and Lower housing members 36 and 38. Referring to Fig. 7, the transmission is shown ~ . . .
as also including a second rotatable shaft 42 supported ;.......
-~.~ within the housing and in parallel spaced apart relation with respect to the drive shaft 28. The opposite -~-~ ends of the rotatable shaft 42 are rotatably supported . .
by bearings 44 (Fig. 2) supported between the side . ~ walls of the upper and lower housing members 36 and~ .
38. The input shaft 26 extends through the front wall of the housing and is perpendicular to the drive shaft 28 and the second rotatable shaft 42. The end of the input shaft extending into the transmission ~ housing 35 supports a bevel gear 46 in meshing engage-- . ment with two spaced bevel gears 48 supported on the rotatable shaft 42. The two spaced bevel gears 48 OOS ~
are each freely rotatable on the rotatable shaft 42 and are driven in opposite rotational directions by the bevel gear 46 secured to the end of the input shaft 26.
A forward and reverse shift dog S0 is supported on the rotatable shaft 42 between the spaced bevel gears 48 and is splined to the rotatable shaft 42 for rotation therewith and for slidable movement along the rotatable shaft 42 between the bevel gears. The forward and reverse shift dog 50 includes projecting lugs 52 which are selectively and alternatively receivable in notches 54 in the ` opposed faces of the spaced bevel gears 48 upon slidable movement of the shift dog 50 along the rotatable shaft 42 between the bevel gears 48 such - - that the bevel gears 48 and the shift dog 50 transmit . . .
;- rotation of the input shaft 26 to the rotatable shaft -..: . .
~ 42. Since the bevel gears 48 are driven in opposite . A .~. ~ .
directions, the direction of rotation of the second.
;-= 20 rotatable shaft 42 can be changed by moving the shift ~- dog 50 from engagement with one of the bevel gears 48 . .
to engagement with the other gear 48. A pair of gears 56 and 58 are respectively keyed to the opposite ends of the rotatable shaft 42, for rotation therewith, the gear 56 of the pair of gears being larger and having a greater number of gear teeth than the other gear 58.
The drive shaft 28 supports a pair of gears 60 and 62 in spaced apart relation, the gear 60 having a larger diameter than gear 62 and meshing with the smaller gear 58 driven by the rotatable shaft 42.
.
~a ~119~05 . The other gear 62 meshes with gear 56 driven by the rotatable shaft 42. Each of the gears 60 and 62 is freely rotatable with respect to the drive shaft 28. An axially slidable shift dog 64 is disposed between the gears 60 and 62 and is splined to the drive shaft 28 for rotation with the drive . shaft 28 but is axially slidably movable along the drive shaft 28 between the gears 60 and 62. The shift dog 64 includes projecting lugs 66 which are selectively and alternatively engageable with notches 68 in the . faces of the opposed gears 60 and 62 whereby rotation ; ~ of one of the gears 60 or 62 is transmitted through ,~
~ the shift dog 64 to the drive shaft 28 for driving .... ...
.~ the drive shaft 28.
: 15 The larger gear 60 is shown as meshing . with a smaller gear 58 on the rotatable shaft 42 and is . - ~
,;~ ~r.;; ~
~~- accordingly driven at a lower rotational speed than . ~, ^ gear 62 meshing with the larger gear 56 on the rotatable shaft 42. Accordingly, shifting of the 'c~ 20 shift dog 64 from engagement with gear 60 into engage- .
- ment with gear 62 will cause an increase in the speed of rotation of the drive shaft 28. As a corollary, movement of the shift dog 64 from engagement with gear 62 to engagement with gear 60 will cause a decrease in the speed of rotation of the drive shaft 28.
Referring to Figs. 7 through 9, movement of the shift dog S0 is controlled by a forward and reverse shifter yoke 70 which is received in an annular groove 72 surrounding the circumference of the shift dog 50. The yoke 70 is attached to a forward and reverse shifter bar 74, the shifter bar 74 being ~ , ~llg~o5 -;
: slidably movable parallel to the rotatable shaft 42 and having its opposite ends supported on two spaced shelves 75 integral with the upper housing member 38 and on opposite sides of the shift dog 50. The shifter yoke 70 extends downwardly between the spaced shelves 75 from the shifter bar 74 to engage the shifter dog 50. The shelves are spaced to define a rectangular opening therebetween receiving the yoke 70 therein and permitting movement of the shifter yoke 70 in the direction of the axis of the shaft 42.
Referring to Figs. 8 and 9, movement of the shifter , ~ bar 74 and the shifter yoke 70 is controlled by a shift lever 76, the shift lever 76 being pivotally attached intermediate its opposite ends by a pivot pin 78 extending upwardly from the upper housing member 38. One of the ends of the shift lever 76 includes ` an opening 80 therethrough receiving a pin 82 extending .. - upwardly from the shifter bar 74. The opening 80 is . , .~ .
~ p larger than the pin 82 to permit overtravel of the . .. ~ -s-w~.. --; 20 shift lever 76 with respect to the shifter bar 74.
One end of an inner wire 84 of a push-pull cable 86 (Fig. 2) is attached to the end of shift lever 76 opposite the end housing opening 80 for causing pivotal movement of the shift lever 76. The push-pull cable 86 is supported by a projection 90 extending . upwardly from the upper housing member 38 and is : retained therein by a pair of nuts 92 and 94.
A forward and reverse detent lever 96 is operable with the shifter bar 74 to selectively maintain the shift dog 50 in engagement with the selected one of the bevel gears48. The detent lever 1119~05 ~
---~ 96 includes a pair of angularly disposed lever arms 98 and 100 and is pivotally attached to the upper housing member 38 intermediate the arms98 and 100 by a plvot pin 99. The lever arm 98 includes a slot 102 for receiving a pin 104 extending upwardly from the shifter bar 74. A compression spring 106 bears against the end of the other lever arm 100 and is maintained in compression between the end of the lever arm 100 and the upper housing member 38. The compression spring 106 releasably maintains the detent lever 96 in either the solid line Dosition shown in Fig. 8 or the dashed line position. When the detent ; lever 96 is in the solid line position shown in Fig.
8, the lever arm 98 of detent lever 96 maintains the shifter bar 74 in the solid line position and the shift dog 50 will be held in engagement with one of the bevel gears 48 by the yoke 70 which extends downwardly from the shifter bar 74. When the detent .
~ lever 96 is in the dashed line position shown in Fig~. 8, :,~
the lever arm 98 of detent lever 96 maintains the shifter bar 74 in the dashed line position and the shift dog 50 will be held in engagement with the other bevel gear 48.
Movement of the shift dog 64 between selective and alternative engagement with the gears 60 and 62 is controlled by a speed selector shifter yoke 108 . which is received in an annular groove 110 surrounding ., .
the circumference of the shift dog 64. The yoke 108 is attached to and e~tends downwardly from a speed selector shifter bar 112, the shifter bar 112 being slidably movable parallel to the drive shaft 28 and 1119005 ~
. having its opposite ends supported on two spaced shelves 114 integral with the upper housing member 38 and on opposite sides of the shift dog 64. The shelves 114 define an opening therebetween for receiving the yoke 108 and for permitting movement of the yoke . 108 in the direction of the axis of the drive shaft 28.
.. ..
...~.
~ ~ The shifter yoke 108 extends downwardly between the .: . ..;
spaced shelves 114 from the shifter bar 112 to engage the shift dog 64. Movement of the shifter bar 112 and t~he shifter yoke 108 is controlled by a speed selector shift lever 116 pivotally attached at one of its ends to the upper housing member 38 by the pivot ... ~ ~
~ pin 78. The other end of the shift lever 116 projects . . ,~
rearwardly from the transmission, and its projecting end forms a manually operable handle for shifting the transmission between low and high speeds. The shift ~ lever 116 includes a slot 118 intermediate its : ~ opposite ends for receiving a pin 120 extending from ~ the upper surface of the shifter bar 112. Lateral '~;~
-~.-~- 20 movement of the projecting end of the shift lever 116 - will result in lateral movement of the shifter bar 112 and similar movement of the yoke 108 and shift dog 64.
The shifter bar 112 is provided with a pair ;
of notches 122 in one of its edges and a detent pin 126 is slidably housed in a bore 128 in the upper housing member 38 and is biased into engagement with the notches 122 by a compression spring 130 therebv releasably restraining the shifter bar 112 and yoke 108 against movement.
The structure described above for shifting the transmission from forward to reverse is independent of ~ .
lll9(~0S (-- the high and low speed shifting means. Accordingly, ... .
the transmission can be shifted from between forward and reverse when the transmission is in either the high or low speed driving modes. Similarly, the transmission can be shifted between high and low speeds when the transmission is in either forward or reverse.
Referring to Figs. 2-3, means are provided for moving the drive shaft 28 and the rear wheels 21 relative to each other between a drive position wherein the friction driving roll 34 frictionally engages the outer periphery of one of the rear wheels 21 and a non-driving position wherein the friction driving roll 34 .. .,--.
is disengaged from the rear wheels 21. More specifically, : the wheels 21 are rotatable with respect to the sup-porting axle 24 which is carried by levers 132 (one shown) pivotably mounted by a pivot 138 on arms 136 (one : shown~ ofa yoke 140. The arm~ ].36 of the yoke 1~0 are fixedly supported from the blade housing 16. The levers 132 project upwardly from the arms 136 and accommodate fore and aft movement of the axle 24 and the rear wheels 21 relative to the drive shaft 28 for respectively engaging the rear wheels 21 with the friction driving . . .
. ~ roll 34 and disengaging the rear wheels 21 from the ~~~ friction driving roll 34. At least one of the levers ; . ,.
132 includes a downwardly extending lever arm portion . . . _ _ .
141, and a tension spring 142 is connected between the ;~ ~ lever arm portion 141 and the blade housing 16 to urge the rear wheels 21 rearwardly with respect to blade housing 16 and toward the disengaged position.
Movement of the rear wheels 21 between the position where they are engaged with friction driving . ~ .
1~19005 ~
.. -` roll 34 and the position where they are disengaged from the friction driving roll 34 is effected by a control handle 143 (Figs. l and 6) mounted on the guiding handle 23 and capable of limited independent movement with respect to the guiding handle 23. An actuator rod 152 is operatively connected at one of its ends to the control handle 143 and is connected at its lower end to the wheel axle 24 through a linkage arrangement.
Oscillatory movement of the control handle 143 with respect to the guiding handle 23 is used to transmit motion through the actuator rod 152. Thus, .. ...
movement of the control handle 143 from the full line neutral position shown in Fig. 6 to the broken line forward position causes the actuator rod 152 to extend downwardly while movement of the control handle 143 `-~ from the full line neutral ~osition to the dashed line reverse position causes the actuator rod 152 to move upwardly.
~*~ 20 Referring to Figs. 3-5, at its lower end the actuator rod 152 is pivotally connected to the end of a lever arm 154 of a compound lever 156. The compound lever 156 is pivotally connected to the yoke arm 136 by a bolt 158 and further includes a lever arm 160 pivotally connected at 162 to a link 164.
~ Another link 166 is pivotally mounted at one end .-.:m............ directly on the axle 24 and its other end is connected . .
to the link 164.
To facilitate adjustment of the clearance between the wheel 21 and the drive roller 34 when the wheel 21 and drive roller 34 are disengaged, the link 164 is provided 1119~05 ~
~:~`~ with a longitudinal slot 174 (Fig. 5~ in its end opposite that connected to the lever arm 160, and the link 166 similarly includes a longitudinal slot 176 in its end opposite that pivotally mounted on axle 24. The links 164 and 166 are secured together by a bolt 178 extending through link 166 and received in the slot . 174 and by an integral tab 180 extending from the link 164 and received in the longitudinal slot 176.
Loosening the bolt 178 permits limited relative slidable movement of the links 164 and 166 for adjustment of the ~ clearance between the wheels 21 and the drive roller 34.
; ~ The shift lever 76 of the transmission 30 is ; ~ also connected to the control handle 143 of the mower such that--forward movement of the control handle 143 to its forward position shown in Fig. 6 causes the .. - shift lever 76 to pivot to its forward drive position ~.....
~ and rearward movement of the control handle 143 ~ .,~, . ..
past the neutral position causes shift lever 76 to pivot to its reverse driving position. To facilitate such connection of the control handle 143 to the shift ~,...
'c'`r,. lever 76 of the transmission 30, the compound lever 156 also includes a downwardly extending lever arm 168 = ..... , j-, .~
connected by pin 169 to an end of the inner wire 84 of the push-pull cable 86. The conduit of the push-pull 25 cable 86 adjacent the lever arm 168 is rigidly supported .
by a bracket 170 attached to the yoke arm 136.
When the control handle 143 is moved forwardly with respect to the guiding handle from the neutral ` :
driving position to the forward driving position, the actuator rod 152 is moved downwardly and the compound lever 156 and links 164 and 166 are moved to the position 11~91005 ~
:: X illustrated by the full line in Fig. 4, thereby pulling axle 24 forwardly toward a wheel engaging position, in which position the a~le 24 is advanced so that the periphery of wheel 21 engages the friction driving $oll 34. At the same time, the downwardly extending lever arm 168 will pull the inner wire 84 of the push-pull cable 86 causing pivotal movement of the shift lever 76 and thereby causing the transmission 30 to be shifted into the forward driving position.
- 10 Movement of the control handle 143 from the forward position to the neutral position effects an upward longitudinal advance of the actuator rod 152, ~;; thereby moving the compound lever 156 and the links 164 and 16~ toward the neutral position shown in Fig.
1. During pivotal movement of the lever 156 from the forward to neutral position, the links 164 and 166 . " .
- will be caused to move rearwardly toward the Position . ~ ..~ .
shown in Fig. 3 whereupon the axle 24 is caused to be moved toward the rearward neutral position.
Movement of the control handle 143 from the .: neutral position toward the reverse position causes rotation of the compound lever 156 and ~ovement of the links 164 and 166 to the position shown in phantom in Fig. 4. As in the shifting motion from neutral to forward, when the compound lever 156 is shifted from the neutral position to the reverse position, the rear axle 24 is pulled forwardly and wheels 21 and 22 engage friction drive rolls 34. At the same time, the downwardly extending lever arm 16~3 will move forwardly as viewed in Figs. 3 and 4 pushing on the inner wire 84 of the push-pull cable 86 thereby ..,... ~ ..
~19(~05 ~
..; =,;
- causing pivotal movement of the shift lever 76 of the transmission into a reverse driving position shown in solid lines in Fig. 8. Such movement of the lever 76 is assisted by a compression spring 171 ~Figs. 2 and 8) compressed between the end of the conduit 86 and the end of the lever 76.
One of the features of the invention is that the transmission 30 is shifted between the forward and reverse driving modes only when the drive wheel 21 is disengaged from the drive roll 34, and the trans-mission is precluded from shifting when the drive wheel 21 is in driving engagement with the drive roll 34.
....-..
- ~ Accordingly, the loads on-the gears of the transmission 30 are reduced before the transmission is shifted between the forward and reverse driving modes. More specifically, when the control handle 143 is in the : forward position shown in dashed lines in Fig. 6, _. the compound lever 156 is in the position shown in . ., ~
` ~ solid lines in Fig. 4 and the drive wheel 21 engages drive roll 34. The transmission shift lever 76 is also in the position shown in phantom in Fig. 8. When the control handle 143 is moved rearwardly toward the .... ,.. ,~, . .
neutral position, the actuator rod 152 causes pivotal movement of the lever 156 toward the solid line position shown in Fig. 3 thereby causing pivotal movement of lever 132 and rearward movement of the axle 24 and drive wheel 21 away from the drive roll 34. Movement of the control handle 143 toward the neutral position also causes the inner wire 84 of conduit 86 to move shift lever 76 from the forward position toward the the reverse position. However, the drive wheel 21 is .
r l~l9~0S
disengaged from driving roll 34 before the lever 76 begins to cause shifting movement of the shift dog 50 of the transmission because the opening 80 in the end of the lever arm 76 for engaging the pin 82 is larger than the pin 82 and permits initial lost motion of the lever 76 before lever 76 acts on pin 82 to cause shifting of the shift dog 50 of the transmission 30 toward the reverse driving position.
As the control handle 143 is moved toward the reverse position shown in Fig. 6, the actuator rod 152 pivots the compound lever 156 toward the position shown in dashed lines in Fig. 4. Such movement of the compound lever 156 will cause the lever arm 168 thereof to move forwardly pushing the inner wire 84 to the position shown in Fig. 8 and moving lever 76 to the solid line position shown in Fig, 8 : wherein the transmission 30 is in its reverse driving . . .
mode. The drive wheel 21 does not engage the drive . roll 34 until the completion of the shifting movement.
Accordingly, the shift lever 76 acts to cause shifting of transmission 30 into the reverse driving position before the drive wheel 21 is moved into driving engage-ment with drive roll 34.
When the control handle 143 is in its reverse driving position, the shift lever 76 assumes the position shown in solid lines in Fig. 8. ~Jhen the control handle 143 is moved from the reverse driving position to the - forward driving position, during initial movement of the compound lever 156 toward its neutral position, the links 164 and 166 and the return spring 142 cause immediate rearward movement of the drive wheel 21 awav .
~119005 ~
. ~ . Y . _.
-.. ` from the drive roll 34. Movement of the control handle 143 and consequent movement of the compound lever 156 also causes movement of the inner wire 84 of the push-pull cable 86 and movement of the shift lever 76. However, since the opening 80 in the . end of lever 76 permits relative lost motion between : the shift lever 76 and the pin 82 connected to the .; . ~
shift dog 50, the transmission does not begin to shift from the reverse to the forward drive position until the drive wheel 21 is disengaged from the drive roll 34.
Various of the features of the invention are set forth in the following claims.
. . . .
...~. ~
...... _ ' ffG'~.~
.'~, ~, , :-~
Claims (9)
1. A self-propelled lawn mower comprising a blade housing, a plurality of wheels for supporting said blade housing, a blade mounted for rotation within said blade housing, a prime mover supported on said housing, a drive shaft mounted for rotation relative to said housing and adapted for connection to one of said wheels for driving thereof, transmission means mounted on said housing and including a rotatable input shaft drivingly connected to said prime mover, a pair of gears mounted co-axially with said drive shaft, means for connecting said input shaft to said pair of gears so as to drive one of said gears at a first speed and so as to drive the other gear at a second speed, and means for alternatively and selectively connecting said gears to said drive shaft for driving said drive shaft, said means including a shiftable element drivingly mounted on said drive shaft between said pair of gears and selectively and alternatively connectable to said gears.
2, A self-propelled lawn mower as set forth in Claim 1 wherein said pair of gears are each supported on said drive shaft and are rotatable on said drive shaft.
3. A self-propelled lawn mower as set forth in Claim 1 wherein said one wheel has a periphery and further including a friction driving roll mounted on said drive shaft for engaging said periphery of said one wheel, means on said housing mounting said one wheel for movement to and from engagement with said friction driving roll, a guiding handle connected to said housing, and means movably mounted on said guiding handle and connected to said means mounting said one wheel for moving said one wheel to and from engagement with said friction driving roll.
4. A self-propelled law mower as set forth in Claim 1 wherein said means for connecting said input shaft to said pair of gears includes a second rotatable shaft drivingly connected to said pair of gears, a second pair of gears driven by said input shaft, and means for selectively and alternatively drivingly connecting said second pair of gears to said second rotatable shaft whereby said drive shaft can be reversibly rotated.
5. A self-propelled law mower as set forth in Claim 4 and further including means operable between said drive shaft and one of said wheels for selectively drivingly engaging said drive shaft to said one wheel, and means connected to said shiftable element and to said means for selectively drivingly engaging said drive shaft to said one wheel for precluding shifting of said transmission when said one wheel is drivingly engaged by said shaft.
6. A self-propelled lawn mower as set forth in Claim 1 and further including means operable between said drive shaft and one of said wheels for selectively drivingly engaging said drive shaft to said one wheel, and means connected to said shiftable element and to said means for selectively drivingly engaging said drive shaft to said one wheel for precluding shifting of said transmission when said one wheel is drivingly engaged by said shaft.
7. A self-propelled lawn mower in accordance with Claim 1 wherein said drive shaft includes a friction driving roll and further including means on said housing for mounting said one drive wheel for movement to and from engagement with said friction driving roll, and means for precluding shifting said transmission until disengagement of said one drive wheel and said friction driving roll, said means for precluding shifting being connected to said means for mounting said one drive wheel.
8. A self-propelled lawn mower as set forth in Claim 7 wherein said means for mounting said one drive wheel is movable from a forward drive position to a neutral position to a reverse drive position, said one drive wheel being in engagement with said friction driving roll when said means for mounting said drive wheel is in said forward drive position and said reverse drive position and said one drive wheel being out of engagement with said friction driving means when said means for mounting said one drive wheel is in said neutral position.
9. A self-propelled lawn mower as set forth in Claim 7 wherein said means for moving said one drive wheel includes a lever arm connected to said wheel mounting means for moving said one drive wheel to and from engagement with said friction driving roll and wherein said shifting means includes a cable having one end connected to said lever arm for movement with said lever arm and another end connected to said transmission for shifting said transmission.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000368820A CA1119005A (en) | 1978-05-30 | 1981-01-19 | Two-speed forward and reverse self-propel system for walk-behind mowers |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US910,573 | 1978-05-30 | ||
| US05/910,573 US4209964A (en) | 1978-05-30 | 1978-05-30 | Two-speed forward and reverse self-propel system for walk-behind mowers |
| CA321,999A CA1099929A (en) | 1978-05-30 | 1979-02-21 | Two-speed forward and reverse self-propel system for walk-behind mowers |
| CA000368820A CA1119005A (en) | 1978-05-30 | 1981-01-19 | Two-speed forward and reverse self-propel system for walk-behind mowers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1119005A true CA1119005A (en) | 1982-03-02 |
Family
ID=27166088
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000368820A Expired CA1119005A (en) | 1978-05-30 | 1981-01-19 | Two-speed forward and reverse self-propel system for walk-behind mowers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1119005A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111726980A (en) * | 2018-11-20 | 2020-09-29 | 南京德朔实业有限公司 | Hand-push type self-driving travelling machine |
-
1981
- 1981-01-19 CA CA000368820A patent/CA1119005A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111726980A (en) * | 2018-11-20 | 2020-09-29 | 南京德朔实业有限公司 | Hand-push type self-driving travelling machine |
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