GB2159684A - Rotary mower - Google Patents

Abstract

In a rotary mower having mowing drums 3 and slide plates 17 which are arranged coaxially with respect thereto, at least one sleeve 15 is provided with a female screwthread 16 and an axial sleeve 10 is provided with a male screwthread 11, which can be moved longitudinally by rotary movement relative to each other, thereby to achieve an adjustment in the height of cut. In the operative position, the sleeve provided with the female screwthread is prevented from rotating relative to the coaxial sleeve with male screwthread by means of a retaining device. <IMAGE>

Description

SPECIFICATION Rotary mower The invention relates to a rotary mowing assembly our a rotary mower comprising at least one mowing drum rotatable about a substantially perpendicular axis, and a slide plate disposed coaxiallywith respect to the mowing drum, the slide plate and the mowing drum being mounted one within the other by means of sleeves which are displaceable relative to each other in the axial direction to adjust the height of cut.

Mowers ofthis type are disclosed for example in German Patent Specification No. 1 915 472. In accordance with that specification, two sleeves which are arranged displaceably one within the other are longitudinally displaceable relative to each other by a screw disposed at a spacing from the axis ofthe drum.

Atool must be inserted into the mowing drum, from above, in orderto adjustthe height of cut. As the mowing drums are disposed beneath the frame of the machine and under a protective covering, difficulties are involved in fitting the tool to the head ofthe screw.

In addition, the eccentric arrangement ofthe screw gives rise to tilting forces which impede easy adjustability of the two sleeves.

In accordance with German Utility Model No.

1 972 328, two sleeves which are providedforthe same purpose are braced by a retaining or locking means. Asthe retaining or locking means however cannot carry the vertical forces which occur in operation ofthe mower, that arrangement additionally includes spacer discs which must be interchanged for the purposes of adjustment ofthe height of cut.

The present invention seeks to eliminate the disadvantages of both constructions. In addition, the invention seeks to provide that the entire height-of-cut adjustment is disposed beneath the mowing drum in order in thatwayto leave the maximum amount of freedom forthe design configuration ofthe mowing drums.

According to the invention, the mowing drums which are rotatable about a perpendicular axis and slide plates which are arranged coaxially with respect to the mowing drums, and which are mounted one within the other by means of sleeves and which are displaceabletherewith relativetoeach other in the axial direction are of such a configuration that at least one ofthe sleeves is longitudinally movable by means of a female screwthread disposed coaxiallywith respectto the perpendicular axis and the sleeve carrying a female screwthread isforce-lockingly or form-locking ly secured against rotary movement relative to another coaxial sleeve or in accordance with an advantageous embodiment ofthe invention is force-lockingly located in position.

Preferably, in addition, a further sleeve which is immovable in the axial direction is provided with a male screwthread which cooperates with the sleeve carrying afemale screwthread.

In a modified embodiment which is not shown in the drawing, the male screwthread may also be cut on the perpendicular shaft itself.

In accordance with another desirable feature, a spring-loaded retaining pin or the like may serve for force-lockingly locating the sleeve provided with a female screwthread, said pin or the like cooperating with openings in another sleeve.

Forthe purposes of axial adjustment as desired (Figure 2) ofthe sleeve which is provided with a female screwthread, and thus for adjusting the height of cut, the sleeve may be non-rotatably connected to the mowing drum by means of a lever orthe like.

In another embodiment (Figure 2), forthat purpose, the sleeve carrying the male screwthread may be non-rotatably connected to the mowing drum by meansofa leverorthe like.

Atool which is provided for changing blades is desirably used as the lever, which tool is inserted into openings or pockets in the mowing drum and fixed therein and bears against an abutment on the sleeve which is to be held fast.

Embodiments ofthe invention will now be described byway of example with reference to the drawings in which: Figure 1 shows a view in section through part of a mowing drum and a slide plate, and Figure 2 shows a corresponding view in section of another embodiment.

A perpendicular shaft 1, 1'which is mounted fixedly or rotatably in the body ofthe machine (not shown) carries a ball bearing assembly 2 with which the lower part of a mowing drum 3,3' (only part thereof being shown) is mounted. The mowing drum 3,3' can be caused to rotate about the perpendicular shaft 1,1' by drive means (not shown).

Two further ball bearing assemblies 4 and 5 are fixed to the lower end ofthe perpendicular shaft 1 (see Figure 1) bymeans of a screw6, awasher7 and sleeves 8 and 9. The outer races ofthe ball bearing assemblies 4 and 5 carry a sleeve 10with a male screwthread 11 which extends over the entire length orpartofthe length ofthesleeve 10. The sleeve 10 is axially fixed. Fixedly connected to the sleeve 10 at the upper wend is a cover 12which in turn has one or more abutments 13. At its periphery, the sleeve 10 has one or more longitudinal grooves 14, the downward extent ofwhich corresponds to the desired adjustmention respect of the height of cut.

Afurthersleeve 15 has a female screwthread 16 and is screwed to the sleeve 10 with the male screwthread 11. Screwed to the lower end ofthe sleeve 15 is a slide plate 17 which is supported by way of a cover plate 18 against the periphery ofthe sleeve 15. In the upper region, the sleeve 15 has a transverse bore 19 which is closed with a plug 20. Disposed in the interior of the transverse bore 19 is a longitudinally movable retaining pin 21 which is urged towards the shaft by the spring 22.

Fixedly connected to the lower part of the mowing drum 3 is a pocket 23 which is closed towards four sides. The free end of a lever 24 can be pushed from the outside through the pocket 23.

Figure 2 shows another embodiment. Fixed on a perpendicular shaft 1' is a ball bearing assembly 2 on which a mowing drum 3' is mounted in the manner described hereinbefore.

Pushed over the shaft 1' is a sleeve 25 which is fixed in the rotary direction by a fitting key 26 and in the longitudinal direction buy a circlip 27. At its periphery, it has a male screwthread 28.

A stepped sleeve 30 which is provided with a corresponding female screwthread 29 is screwed over the sleeve 25. The sleeve 30 has a bore 31 with a retaining pin 32 and a spring 33. Fixedly screwed to the lower end ofthe sleeve 30 is an abutment plate 34.

The lowerfree end oftheperpendicularshaft 1' has asplinearrangement35orthe like over which a further sleeve 36 is fitted so as to be non-rotatable but longitudinally movable thereon. Atthe upperend,the sleeve 36 has a stepped flange 37 with which it is guided rotatably but axially immovably between the stepped sleeve 30 and the abutment plate 34. The sleeve 36 carries two ball bearing assemblies 38 and 39 which in turn carry a ring 40 to which the slide plate 17 is connected. The top side ofthe stepped flange 37 has one or more openings 41 into which the pin 32 can engage.

In a similarfashion as shown in Figure 1, the free end of a lever 24 can be passed through a slot 42.

The mode of operation of a rotary mower as shown in Figure 1 asasfollows: In the mowing operation,the mowing drum 3 is driven and rotates aboutthe perpendicular shaft 1.

The sleeves 10 and 15 which are screwed one overthe other are locked by way ofthe retaining means 20,21, 22 and 14. The slide plate 17 bears againstthe ground and can rotate if necessary by means of the ball bearing assemblies 4 and 5.

Forthe purposes of adjustment ofthe height of cut, the mowing drum 3 is stopped and the mower is raised. The free end of a lever 24 is introduced from the outside between the mowing drum 3 and the slide plate 17 and advanced through the pocket 23 to such an extent that it comes into operative cooperation with the abutment 13 and is thus fixed in position.

Because ofthat, the sleeve 10 can no longer rotate on the ball bearing assemblies 4and 5.

By rotating the slide plate 17 by hand, the action of the retaining means 20,21,22 and 14 is overcome and the sleeve 15 is moved upwardly or downwardly by means ofthe screwthread 11,16, depending on the direction of rotation. That gives rise to a different spacing between the mowing drum 3 and the slide plate 17, which results in an altered mowing height.

In the case of a rotary mower as shown in Figure 2, a lever 24 is introduced at an inclined anglefrom above through a slot 42 in the mowing drum 3' until it comes into operative engagement with an abutment 34. By virtue ofthat cooperation, the sleeve 30 which is fixedly connected to the abutment 34 can no longer rotate with respect to the mowing drum 3'.

If nowthe mowing drum 3' is rotated by hand, the action ofthe retaining means 31,32,33 and 41 is overcome and the stepped sleeve 30 rotates on the screwthread 28 and 29 and thereby is moved upwardly or downwardly. When the required heightwise position is reached, the rotary movement ofthe mowing drum 3' is stopped and the lever 24 is removed.The mower is then again readyfor operation.

Claims (9)

1. A rotary mowercomprising at least one mowing drum rotatable about a susbtantially perpendicular axis, and a slide plate disposed coaxiallywith respect to the mowing drum, the slide plate and the mowing drum being mounted one within the other by means of sleeves which are displaceable relative to each other in the axial direction to adjust the height of cut, wherein at least one ofthe sleeves is longitudinally movable by means of a female screwthread which is arranged coaxially with respect to the vertical axis and the sleeve carrying a female screwthread is forcelockingly orform-lockingly prevented from rotating relative to another coaxial sleeve.

2. A rotary mower according to claim 1 wherein the sleeve which carries a female screwthread is force-lockingly located in position relative to another coaxial sleeve.

3. A rotary mower according to claim 1 or claim 2 wherein a second sleeve which carries a male screwthread and which cooperates with the sleeve carrying a female screwthread is axially immovably connected to a perpendicular shaft.

4. A rotary mower according to claim 1 or claim 2 wherein that a perpendicular shaftcarries a male screwthread and cooperates with the sleeve carrying a female screwthread.

5. A rotary mower according to any of claims 1 to 4 wherein a spring-loaded retaining pin orthe like servesforforce-lockingly locating the sleeve provided with a female screwthread, said pin orthe like cooperating with openings in another sleeve.

6. A rotary mower according to any of claims 1 to 5 wherein for the purposes of axial adjustment as required ofthe sleeve provided with a female screwthread, said sleeve can be non-rotatably connected to the rotatable mowing drum by means of a leverorthe like.

7. A rotary mower according to any of claims 1 to 5 wherein, forthe purposes of axial adjustment as required of the sleeve provided with a female screwthread, the sleeve provided with the male screwthread can be non-rotatably connected to the mowing drum by means of a lever orthe like.

8. A rotary mower according to claim 6 or claim 7 wherein a leverwhich is provided for changing blades is used for non-rotatably connecting a sleeve to the mowing drum which lever is introduced into openings or pockets of the mowing drum and fixed therein and bears against an abutment ofthe sleeve which is to be held fast.

9. A rotary mowersubstantial ly as described with reference to Figure 1 or Figure 2 of the drawings.