US3570637A

US3570637A - Blade drive and braking arrangement for a rotary lawn mower

Info

Publication number: US3570637A
Application number: US781218A
Authority: US
Inventors: Donald L Pitman; Gilbert B Hahn; Martin J Gencsi
Original assignee: Murray Ohio Manufacturing Co
Current assignee: Murray Ohio Manufacturing Co
Priority date: 1968-12-04
Filing date: 1968-12-04
Publication date: 1971-03-16
Anticipated expiration: 1988-03-16

Abstract

A system for driving and braking a blade in a rotary lawn mower. An arm is pivotally connected to a blade housing. The free end of the arm carries an idler pulley which, on rotation of the arm in one direction, is moved to tension a belt which also passes about a drive pulley and a pulley connected to the blade. The belt tensioning causes the blade to be driven. On rotation of the arm in the opposite direction, the belt tension is released and a brakeshoe carried on the arm engages the blade pulley to terminate blade rotation. Direction of rotation of the arm is controlled by a mechanical linkage from an operator''s lever.

Description

United States att Donald L. Pitman; Gilbert B. Hahn; Martin J. Gencsi,

[72] Inventors Nashville, Tenn. [21] AppLNo. 781,218 [22] Filed Dec. 4, 1968 [45] Patented Mar. 16, 1971 [73] Assignee The Murray Ohio Manufacturing Company Nashville, Tenn.

[54] BLADE DRIVE AND BRAKING ARRANGEMENT FOR A ROTARY LAWN MOWER 3 Claims, 4 Drawing Figs.

[52] US. Cl 192/11, 188/259, 56/25.4 [51] Int. Cl l. Fl6h 57/10 [50] Field of Search 192/11 [56] References Cited UNITED STATES PATENTS 1,727,933 9/1929 Mitchell 192/11 Primary Examiner-Benjamin W. Wyche Attorney-Cushman, Darby and Cushman ABSTRACT: A system for driving and braking a blade in a retary lawn mower. An arm is pivotally connected to a blade housing. The free end of the arm carries an idler pulley which, on rotation of the arm in one direction, is moved to tension a belt which also passes about a drive pulley and a pulley connected to the blade. The belt tensioning causes the blade to be driven. On rotation of the arm in the opposite direction, the belt tension is released and a brakeshoe carried on the arm engages the blade pulley to terminate blade rotation. Direction of rotation of the arm is controlled by a mechanical linkage from an operators lever.

MADE DRIVE AND BRAKWG ARRANGEMENT FQR A RQTARY LAWN MOWER In the field of rotary lawn mowers two important characteristics of a quality mower are an effective power train and a quick means for breaking the blade when the power train is disengaged. In most mowers the blade is rotated by a belt connected between the drive shaft of a motor and a blade pulley. With such a system, when the belt is released from driving relationship with the blade pulley, the blade freewheels.

It is desirable to provide an arrangement for integrating the blade driving and braking operation whereby on disengaging the blade drive, the blade is automatically braked and vice versa. It is the purpose of this invention to provide an improved arrangement for obtaining such action. By the structure to be hereinafter described a safety advantage is obtained due to the rapid braking action which may be achieved. Furthermore, belt tension and brake wear are controlled by a unique spring arrangement which is employed. In addition, the system is simple and easily accessible thereby facilitating maintenance and repair by the user.

Briefly, the invention comprises a drive belt passed about a drive pulley, an idler pulley and a pulley joined to the blade. An arm is pivotally attached to the housing for the blade, and the idler pulley is mounted on the arm. When the arm is pivoted in one direction, the belt is tensioned by engagement with the idler pulley to cause rotation'of the blade, and when the arm is pivoted in the opposite direction, belt tension is released. The arm also carries a brakeshoe which, when the arm is pivoted to release belt tension, engages the blade pulley to stop it from further rotation. Pivoting of the arm is controlled by an operators lever, and a spring is connected between the lever and the arm to establish the degree of tension the idler pulley supplies to the belt when in engagement therewith. The spring also assists in locking the lever when it is moved to permit braking.

The invention will become more apparent when considered in light of the following detailed description of an illustrative embodiment of the invention and from the appended claims.

The illustrative embodiment may be best understood by reference to the accompanying drawings, wherein:

FIG. l is an exploded perspective view of the blade driving and braking arrangement according to the invention;

FIG. 2 is a perspective view of the arrangement of FIG. 1 in the blade driving mode; and

H6. 3 is a perspective view of the arrangement of FIG. I in the blade braking mode.

Referring now to the drawings, the invention will be described in detail.

H6. 1 is an exploded view of the elements which form the improved blade braking system. A conventional rotary mower blade housing is generally indicated as 10. This housing is adapted to be attached, for example, to the underside of a riding-type mower. Wheels 12 and 14 are mounted to the housing in conventional fashion. A rotary mower blade 16 is positioned within the housing by the usual connection of the blade to a pulley 18 located on the opposite side of the housing from the blade. The interconnection of blade l6 and the pulley 13 is by a conventional bearing arrangement passing through an aperture 20 at the center of housing 10. The bearing and associated connecting elements are clearly illustrated in FIG. 1 and, therefore, need not be described in detail. It is obvious, however, that on rotation of the pulley 13, the blade 16 rotates within the housing 10.

Adjacent aperture 20 in housing 10 is an additional aperture 22. A fastening arrangement extends through aperture 22 to pivotally connect one'end of an arm 24 to the upper surface of housing 10. The free end of the arm carries a bearing element 26 on which an idler pulley 28 is mounted for rotation. A V- shaped drive belt 39 is passed about

pulleys

18 and 28 as well as a main drive pulley 32, the latter being connected to a conventional mower power source (not shown).

A tab 34 is provided at the free end of the arm 24, adjacent the bearing element 26, to retain the drive belt in proximity to pulley 23 regardless of belt tension. Additional tabs 36 and 3b are provided on the arm 24 intermediate its ends. Opposite ends of a strip of spring material 40 are connected to

tabs

36 and 38 by riveting or by other suitable securing means. A strip of brakeshoe material 42 is fastened to the spring 40 inter-' mediate its ends. Shoe 42 is arcuate in shape having a curvature generally corresponding to that of the drive pulley 18.

A U-shaped bracket 44 is also fixed to the upper surface of housing 10. The arms of this bracket are provided with aligned apertures through which a straight portion of a lever bar 46 extends. This bar is secured with respect to the bracket by means of pins 48 and t) passing through apertures in the bar beyond the arms of bracket 44. The bar 46 has an approximately bend to form a handle portion 52 which is convenient to the operator of the mower. By actuating handle 52, the bar pivots within bracket 44.

A connecting element 54 is fixed at one end to the portion of bar 46 intermediate the arms of bracket 44. A connecting link 56 is pivotally mounted at one of its ends to the free end of element 54. The opposite end of link 56 is passed through an aperture 58 in arm 24. Thus, when handle 52 is actuated to rotate connecting element 54, arm 24 is pivoted about its secured end through the agency of connecting link 56. A spring 60 is connected at one end to the portion of bar 46 between the ends of bracket 44, and the opposite end of the spring 60 is attached to tab 36 projecting upwardly from the arm 24.

Now that the structure of the invention has been presented, its operation will be described with particular reference to FIGS. 2 and 3.

It will be assumed that the power source for the mower is in operation thereby driving pulley 32. In order that pulley 18 and blade 16 be rotated, the belt 30 must be taut. By actuating handle 52 so as to rotate connecting element 54 clockwise about its fixed end (the clockwise direction being as shown in FIG. 2), the arm 24 is similarly pivoted in a clockwise direction about its fixed end (as viewed from the top in FIG. 2) so as to carry idler pulley 28 into tensioning engagement with the belt. The force of spring 60, which tends to rotate the arm in a clockwise manner, controls the degree of tension applied by the idler pulley 28 on belt 30 to thereby permit blade pulley 18 to be rotated. Furthermore, the spring 60 permits the operator to release the handle without the idler pulley 28 being disengaged from operative relationship with belt 30.

When a blade braking operation is desired, handle 52 is moved, as shown in FIG. 3, to rotate connecting element 54 in a counterclockwise direction. The resultant action of connecting link 56 serves to rotate the arm in a counterclockwise direction (as viewed from the top in FIG. 3). This relieves the tension on belt 30, thereby disengaging the mowers power source from pulley l8. Unless positively stopped, however, pulley l8 and the attached blade 16, would continue to freewheel for a considerable period. To prevent this, the counterclockwise movement of the arm also brings the brakeshoe 42 into engagement with the rims of pulley 1% (which rims project beyond belt 30). The operator continues to move handle 52 until the connecting element 54 passes the spring 695 overcenter position with respect to the portion of bar 46 within bracket 44. At this point, release by the operator of handle 52 results in spring 6t continuing to urge element 54 in a counterclockwise direction until the free end of the element rests on the top of housing 10 to lock the device in the braked condition. The spring so is tensioned so as to maintain the brakeshoe 42, in continuous engagement with the rims of pulley 18 while the handle 52 is in the locked position. Thus, the freewheeling pulley lfi is quickly stopped.

From the foregoing description, the advantages of the present invention are apparent. The blade brake is an integral part of the blade drive control system such that the brake is automatically applied when the drive is disconnected from the blade. This is an important safety feature. Furthermore, the brakeshoe, positioned intermediate the ends of a spring strip 4b, is worn evenly as the spring automatically positions the brakeshoe in alignment with the rims of pulley 18. Also, the brakeshoe does not contact the belt 30 so as to reduce the belt life. Additional advantages are that the entire blade drive is self-contained, it is assembled to the mower housing, and it is independent of the remainder of the mower chassis. Thus, the arrangement is readily accessible for service and maintenance.

The above-described embodiment is illustrative of a preferred embodiment of the invention but is not intended to limit the possibilities of insuring the features of positive blade drive and rapid blade braking. The structure disclosed herein is an example of an arrangement in which the inventive features of this disclosure may be utilized, and it will become apparent to one skilled in the art that certain modifications may be made within the spirit of the invention as defined by the appended claims.

We claim:

l. An arrangement for driving and braking a blade mounted for rotation within a blade housing of a rotary lawn mower, comprising:

a. a pulley operatively connected to said blade;

b. a drive pulley joined to a power source to be rotated thereby;

c. an arm pivotally attached to said housing and having an idler pulley mounted thereon;

d. lever means operatively connected to said arm to pivot same to move said idler pulley into and out of tensioning engagement with the belt; and

e. a brakeshoe attached to a spring strip which is fastened at its ends to said arm, said shoe braking the blade pulley when the arm is pivoted to move the idler pulley out of tensioning engagement with the belt.

2. An arrangement for driving and braking a blade mounted for rotation within a blade housing of a rotary lawn mower, comprising:

a. a pulley operatively connected to said blade;

b. a drive pulley joined to a power source to be rotated thereby;

d. lever means operatively connected to said am to pivot same to move said idler pulley into and out of tensioning engagement with the belt, said lever means including: aa. a rotatable lever bar; bb. a connecting element attached at one end to said lever bar;

cc. a connecting link joining the other end of said connecting element to the arm pivotally attached to the housing;

the arrangement further including:

dd. a spring connected at one end to said pivotally attached arm and at its other end to said lever bar, said spring being tensioned to urge said arm to pivot towards the lever bar whereby when the lever bar is actuated to place the idler pulley in tensioning engagement with the belt, the spring determines the degree of tension on the belt, and when the lever bar is actuated to remove the idler pulley from tensioning engagement with the belt, the spring is displaced in an overcenter relationship with respect to the bar to force the connecting element into engagement with the housing thereby locking the lever bar; and

e. a brakeshoe mounted on said am to brake the blade pulley when the arm is pivoted to move the idler pulley out of tensioning engagement with the belt.

3. An arrangement according to claim 2, wherein said brakeshoe is attached to a spring strip fastened at its ends to said arm.

Claims

1. An arrangement for driving and braking a blade mounted for rotation within a blade housing of a rotary lawn mower, comprising: a. a pulley operatively connected to said blade; b. a drive pulley joined to a power source to be rotated thereby; c. an arm pivotally attached to said housing and having an idler pulley mounted thereon; d. lever means operatively connected to said arm to pivot same to move said idler pulley into and out of tensioning engagement with the belt; and e. a brakeshoe attached to a spring strip which is fastened at its ends to said arm, said shoe braking the blade pulley when the arm is pivoted to move the idler pulley out of tensioning engagement with the belt.

2. An arrangement for driving and braking a blade mounted for rotation within a blade housing of a rotary lawn mower, comprising: a. a pulley operatively connected to said blade; b. a drive pulley joined to a power source to be rotated thereby; c. an arm pivotally attached to said housing and having an idler pulley mounted thereon; d. lever means operatively connected to said arm to pivot same to move said idler pulley into and out of tensioning engagement with the belt, said lever means including: aa. a rotatable lever bar; bb. a connecting element attached at onE end to said lever bar; cc. a connecting link joining the other end of said connecting element to the arm pivotally attached to the housing; the arrangement further including: dd. a spring connected at one end to said pivotally attached arm and at its other end to said lever bar, said spring being tensioned to urge said arm to pivot towards the lever bar whereby when the lever bar is actuated to place the idler pulley in tensioning engagement with the belt, the spring determines the degree of tension on the belt, and when the lever bar is actuated to remove the idler pulley from tensioning engagement with the belt, the spring is displaced in an overcenter relationship with respect to the bar to force the connecting element into engagement with the housing thereby locking the lever bar; and e. a brakeshoe mounted on said arm to brake the blade pulley when the arm is pivoted to move the idler pulley out of tensioning engagement with the belt.