GB1564492A

GB1564492A - Mowing machines

Info

Publication number: GB1564492A
Application number: GB63378A
Authority: GB
Original assignee: NIEMEYER BETEILIGUNGS GmbH
Current assignee: NIEMEYER BETEILIGUNGS GmbH
Priority date: 1977-01-27
Filing date: 1978-01-09
Publication date: 1980-04-10
Also published as: DE2703301A1; NL7713697A; FR2378437A1

Description

(54) IMPROVEMENTS IN MOWING MACHINES (71) We, NXEMEYER BETEILIGUNGS- CZ13;LLSCHAFr MIT BESCHRANKTER HAFTUNG tla. H.SrJIEMEYER SOHNE GmbH & Co. KO a, company of the Federal Republic of Germany, do hereby declare the invention, for VVhiCh we pray that a patent may be granted to us, and - the method by which it is to be performed to be particularly described in a, by the following statement: The present invention relates to mowing hinges., It is known to provide a rowing machine having a frame mounting drum-like cutting bodies each of whioh is rotatable about a vertical axis and which carries at its lower end an annular collar and cutting blades freely pivoted to the collar, the blades pro acting beyond the periphery of the collar in their cutting position.

In the known mowing machines of this kind, the cutting blades are disposed below the annular collar and are rotatable about pns which have a pin portion projecting downwards beyond the under side of the annular collar and are screwed into the annular collar. The parts of the cutting Blades which are situated below the annular collar in the cutting position and their securing means may be covered at the bottom, and therefore protected from damage, by a freely rotatable, ground-engaging supporting member provided co-axially below the cutting body, if this has substantially the same diameter as the diameter of the annular collar. In embodiments of the machines having supporting members which are smaller in external diameter and which leave the cutting blades and their securing means steely exposed towards the ground, separate protecting members have to be provided at t!he underside of the annular collar to protect the pins and the radially inner portions of the cutting blades, which are exposed at the bottOm, from contact with stones etc. Such protecting members, for example welded-on protecting plates etc., are exposed to considerable wear and unwanted deformation on contact with the ground, in view of the speeds of rotation of the cutting bodies.

Since the cutting blades are, in turn, exposed to l'eavy wear and to damage on impingement with foreign bodies in their radially outer regions, projecting beyond the periphery of the annular collar, when the blades are in the cutting position, it is necessary to replace the cutting blades at frequent intervals. Such a replacement should, if possible, be able to be carried out quickly in the field, and, ideally, without much use of tools, so that mowing operations which have begun do not have to be interrupted for an unnecessary long time because of blade wear or damage. It is true that the unscrewing of the pins from the annular collar for the purpose of blade replacement can generally be carried out relatively quickly and easily with a monkey wrench, but difficulties then arise if the blade securing means are greatly worn or deformed.

Problems arise even in machine embodiments wherein the annular collar and the supporting member have substantially the same diameter and form a narrow annular gap which only slightly exceeds the thickness of the cutting blade and through which the cutting parts of the blades project, if the distance between the cutting plane of the cutting blades and the supporting member resting with its under side on the ground, is increased for the purpose of adjusting the height of the cut. In this case, particularly with relatively great cutting heights, the distance between the outer edges of the annular collar and the supporting member is increased so that stones etc., can enter the gap between the two and cause damage to the blades and their securing means. This is the case, in particular, when the pins for the cutting blades are secured to the top of radial leaf spring elements and merely engage in bores in the annular collar from which they can be withdrawn by bending the leaf spring downwards. Such leaf springs are particularly easily damaged and run the risk of being bent down during the mowing operation, as a result of which the cutting blades can come loose from their pins.

The present invention provides a mowing machine comprising a rotatable cutting body having a lower end portion carrying cutting blades freely pivoted on pins so that the blades can swing out into a cutting position, said lower end portion including spaced upper and lower members, and the cutting blades are positioned in the space between said members, said pivot pins being carried on the under side of the upper member which is formed separately and which is flexibly supported from a further part of the cutting body for limited displacement relative to the lower member.

With a machine in accordance with the present invention, the cutting blades and their securing means are directly protected from any effects of stones and contact with the ground by the under side of the lower member. The covering of the cutting blades and their pivot pins at the ground side by the lower member is obtained regardless of what height of cut is actually set and accordingly what distance the lower member has from the ground. The upper member with the pivot pins carried thereby is reliably protected from ground collision but, because of its resiliently flexible support on the cutting body, minor tilting displacements of it are permitted which render it possible to lift, in turn, the lower ends of the pivot pins from the top of the lower member in order to be able to remove worn blades quickly and easily and to fit new ones. The supporting member, normally provided, is relieved of any protective function and can therefore be constructed, in shape and dimensions, exclusively according to its supporting function.

A specific embodiment of the present invention will now be described by way of example, and not by way of limitation, with reference to the accompanying drawings in which: Fig. 1 shows, illustrated diagrammatically, a section through a cutting body of a mowing machine according to the invention; Fig. 2 shows a sectional illustration, similar to Fig. 1 with the cutting body displaced upwards in relation to the supporting member in order to increase the height of cut; Fig. 3 shows an enlargement of the detail III in Fig. 1; and Fig. 4 shows an enlargement of the detail IV in Fig. 1.

With reference now to the accompanying drawings, the mowing machine illustrated in the drawings comprises a frame, not illustrated, with which the machine can be attached to the three-point hydraulic lift system of an agricultural tractor. The frame carries a supporting beam 1 which in turn carries, at its under side, generally two or four cutting bodies 2 which are rotatable oppositely in pairs. Each cutting body 2 comprises a substantially cylindrical drum 3 which is mounted for rotation about a substantially vertical axis of rotation 4 and has an attachment flange 5 projecting beyond its periphery at its lower end. In the example illustrated, this attachment flange 5 is formed by the outer edge of a lower stiffening plate 6 which is welded into the lower end of the drum 3 of the cutting body 2.

A supporting tube 7, which is rigidly connected to the supporting beam 1 and forms a hollow shaft and through which a drive shaft 8 extends co-axially, is provided to mount the cutting body 2. At its upper end, the drive shaft motion is imparted to the drive shaft 8. The lower end of the drive shaft 8, projecting beyond the supporting tube 7, is rigidly connected to a driving bush 10 which extends from the connecting region with the drive shaft 8 co-axially upwards towards the supporting beam 1 and is supported on the supporting tube 7 through bearings 11, 12. The driving bush 10 is further extended a distance downwards beyond the connecting region with the drive shaft 8 and is provided, co-axially inside this extension region, with a pin 13 on which a hub sleeve 16 of a dish-shaped supporting member 17, which engages from below with its upper end in the driving bush 10, is mounted for free rotation through bearings 14, 15. The supporting member 17 has the form of a substantially flat sliding plate with an upturned outer edge portion. Each cutting body is supported on the ground by means of a supporting member 17.

Disposed for axial displacement and location on the driving bush 10 is an inner supporting sleeve 18, which is associated co-axially with the drum 3 and is connected to it through the stiffening plate 6 and a further stiffening plate 19. An axially fitting key, not illustrated, is provided between the driving bush 10 and the inner supporting sleeve 18 to ensure the mutual non-rotatability of these two components which are axially displaceable in relation to one another. In its upper region the driving bush 10 comprises an encircling flange 20 in which a setscrew 21 is rotatably mounted.

This setscrew 21, which is aligned parallel to the axis of rotation 4, engages with its lower threaded portion 22 in a nut 23 which is welded to the stiffening plate 19 below a passage. If a monkey wrench 26 is now introduced through an access socket 24 in an upper covering hood 25 for the cutting body 2 and is placed on the head of the setscrew 21, then the drum 3 can be axially adjusted in its spacing relation to the supporting member 17 in order to adjust the height of cut, in a simple manner by turning the monkey wrench 26. This is done with the cutting body 2 at a standstill. Figure 1 illustrates the cutting body 2 in its lower position with a minimum height of cut, while Figure 2 illustrates the cutting body 2 in its upper position with the maximum height of cut.

As can be seen, in particular, from Figure 3, the cutting body 2 comprises a lower end portion including a lower member in the form of an annular collar 27 which is formed as a separate component detachably connected to the flange 5. This annular collar 27 is secured to the attachment flange 5 by means of screw bolts 28 which engage through spacer sleeves 29 disposed between the under side of the attachment flange 5 and the top of the internal edge region of the annular collar 27.

A plurality of screw bolts 28 together with spacer sleeves 29, regularly distributed over the periphery of the cutting body, are provided to locate the annular collar 27 on the attachment flange 5. Provided with spacing above the annular collar 27 and included in the lower end portion of the cutting body 2 is an upper member in the form of an annular cover plate 30 which in turn is formed separately and which is supported detachably and with limited resilient flexibility from the flange 5. Near its outer periphery, this annular cover plate 30 carries pins 31 for pivotally mounting cutting blades 32, each blade 32 being freely rotat able about its pin 31. Each cutting body generally comprises two, three, four or more cutting blades 32 regularly distributed over the periphery of the cutting body. The pins 31 for the cutting blades 32 are formed by a socket-head cap screw of which the screw head provided with an external thread is followed by a pin portion 331 which is reduced in diameter and provided with an encircling bearing notch or groove 34 for the cutting blade 32. The pin 31 is screwed into a tapped annular member 35 which is welded into a bore 36 in the annular cover plate 30 and comprises a stop shoulder 37 which engages under the threaded head of the pin. As can be seen from Figure 4, the lower ends of the pins 31 rest on the top of the annular collar 27, the lower ends of the pins bearing under unitial tension against the top of the annular collar 27 as a result of the resilient support of the annular cover plate 30 on the cutting body 2. The annular collar 27 comprises pockets 38 which receive the centre and lower ends of the pins 31 and which are formed by depressed portions 39 stamped into the annular collar 27. Seen in the direction of the pin axis 40, the bearing notch 34 in the pin portion 331 of the pin 31 has a width w;hich, in the example illustrated, is substantially equal to the distance between the under side 41 of the tapped annular member 35 and the undeformed top surface 42 of the annular collar 27. The width of the bearing notch 34 is greater than the thickness of the cutting blade 32 so that this can, if necessary, rotate unhindered about the pin axis 40. For sliding over their pins 31, the cutting blades 32 comprise, in their inner attachment part, a bore 43, the diameter of which is only slightly larger than the external diameter of the pin portion 331, When the cutting body 2 is at a standstill, sliding a cutting blade 32 over the pin 31 does not involve any difficulties, whereas, when the mowing machine is in operation with the cutting bodies rotating, the bearing notch 34 ensures that the fitted cutting blade 32 cannot become detached downwards from the pin regardless of the support of the lower end of the pin 31 in the pocket 38 of the annular collar 27. Between them, the annular collar 27 and the annular cover plate 30 bound an axially symmetrical, substantially annular disc-shaped gap which, at least in the region of the imaginary circle of rotation of the cutting blade 32 about its pin 31, has an alignment falling obliquely downwards and outwards, that is to say, extends slightly conically. This conicity afforded by an appropriate shaping of the annular collar 27 and the annular cover plate 30 increases the moment of resistance of these parts to deformation in service. In the example illustrated, the gap 44 has a width which remains constant radially from the inside outwards in the whole region between the inner edge of the annular collar 27 and the annular cover plate 30 and their outer edges, but may also have a construction diverging slightly radially from the inside outwards to facilitate the throwing out of any particles of cut material or soil which try to penetrate in. The outer marginal edge 45 of the annular cover plate 30 has a diameter which is slightly smaller than the diameter of the outer marginal edge 46 of the annular collar 27 so that the annular cover plate is set back slightly at the outer edge in comparison with that of the annular collar. This ensures that in the event of encountering a stone or similar solid body on the ground, the outer edge 46 of the annular collar 27 rigidly connected to the cutting body 2 comes into contact with the stone and protects the annular cover plate 30 from such contact.

The annular cover plate 30 engages with its inner edge (Figure 3) between the attachment flange of the cutting body and the inner edge of the annular collar 27. The plate 30 comprises openings 47 through which the spacer sleeves 29 engage with clearance and the plate is gripped - between two holding rings 48, 49 of resilient material, for example, rubber or rubbery elastic plastics or other elastomeric material. The holding rings 48, 49 engage above and below the inner edge of the annular cover plate 30.

The holding rings in turn have openings for the spacer sleeves 29 and surround these spacer sleeves 29 in the region of these openings without a gap. When the annular collar 27 is screwed on, the holding rings 48, 49 are compressed between its inner edge and the attachment flange 5 of the cutting body 2. The holding rings 38, 49 are so dimensioned in their thickness seen in the direction of the axis 50 of the screw bolts 28, that the inner edge of the annular cover plate is disposed at about half the height of the spacer sleeves 29 which have their largest external diameter in this region and decrease in their external diameter towards each end. The result is a certain double frusto-conical or barrel-shaped external contour of the spacer sleeves 29 which, with the resilient gripping or support of the annular cover plate 30, allows minor displacements of this plate in the tilting sense.

The thickness dimensions of the holding rings 48, 49 are further so selected that when the holding rings 48, 49 are compressed with the screw bolts 28 tightened, the lower ends of the pins 31 bear with the above-mentioned initial tension against the top surface of the annular collar 27 in its pockets 38.

While assurance is provided, in this manner, that detachment of the cutting blades 32 is out of the question during the cutting operation, on the other hand, the possibility is opened up of tilting the annular cover plate 30 slightly, in the region of a pin 31, against the resilient resistance of the holding rings, by engaging with a tool between the annular collar 27 and the annular cover plate 30, so as to lift the pin 31 out of the pocket 38 to effect a change of blade.

WHAT WE CLAIM IS:- 1. A mowing machine comprising a rotatable cutting body having a lower end portion carrying cutting blades freely pivoted on pins so that the blades can swing out into a cutting position, said lower end portion including spaced upper and lower members, and the cutting blades are positioned in the space between said members, said pivot pins being carried on the under side of the upper member which is formed separately and which is flexibly supported from a further part of the cutting body for limited displacement relative to the lower member.

2. A mowing machine as claimed in claim 1 in which the upper and lower members define between them a downwardly and outwardly directed gap housing the cutting blades.

3. A mowing machine as claimed in claim 1 or 2 in which the upper and lower members define between them a gap which widens radially outwardly.

4. A mowing machine as claimed in claim 1 or 2 in which the upper and lower members are uniformly spaced.

5. A mowing machine as claimed in any preceding claim in which the upper member has an outer marginal edge of a diameter which is substantially equal to or slightly smaller than the diameter of the outer marginal edge of the lower member 6. A mowing machine as claimed in any preceding claim in which the lower member is formed separately and is detachably conected to said further part of the cutting body via screw bolts engaging through spacer sleeves.

7. A mowing machine as claimed in claim 6 in which the upper member is clamped by holding rings between said further part of the cutting body and the lower member, the upper member being provided with openings for said spacer sleeyes, and for each sleeve two of said holding rings being provided which engage opposite sides respectively of the upper member.

8. A mowing machine as claimed in claim 7 in which said openings surround the spacer sleeves with clearance.

9. A mowing machine as claimed in claim 7 or 8 in which the spacer sleeves have their largest external diameter substantially at the level of said openings in the upper member and decrease in external diameter towards both their ends.

10. A mowing machine as claimed in any preceding claim in which the lower ends of the pivot pins are supported on the top surface of the lower member.

11. A mowing machine as claimed in claim 10 in which the lower ends of the pivot pins are held in engagement with the top surface of the lower member by virtue of the flexible support afforded to the upper member.

12. A mowing machine as claimed in claim 10 or 11 in which the lower member has pockets which receive and center the lower ends of the pivot pins.

13. A mowing machine as claimed in claim 12 in which the pockets are formed by depressing portions of the lower member.

14. A mowing machine as claimed in any preceding claim in which the pivot pins are each formed by a socket-head cap screw of which the screw head is provided with an external thread and is followed by a pin portion which is reduced in diameter and provided with an encircling bearing notch for its cutting blade.

15. A mowing machine as claimed in claim 14 in which each pivot pin is screwed into a tapped annular member which is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. openings without a gap. When the annular collar 27 is screwed on, the holding rings 48, 49 are compressed between its inner edge and the attachment flange 5 of the cutting body 2. The holding rings 38, 49 are so dimensioned in their thickness seen in the direction of the axis 50 of the screw bolts 28, that the inner edge of the annular cover plate is disposed at about half the height of the spacer sleeves 29 which have their largest external diameter in this region and decrease in their external diameter towards each end. The result is a certain double frusto-conical or barrel-shaped external contour of the spacer sleeves 29 which, with the resilient gripping or support of the annular cover plate 30, allows minor displacements of this plate in the tilting sense. The thickness dimensions of the holding rings 48, 49 are further so selected that when the holding rings 48, 49 are compressed with the screw bolts 28 tightened, the lower ends of the pins 31 bear with the above-mentioned initial tension against the top surface of the annular collar 27 in its pockets 38. While assurance is provided, in this manner, that detachment of the cutting blades 32 is out of the question during the cutting operation, on the other hand, the possibility is opened up of tilting the annular cover plate 30 slightly, in the region of a pin 31, against the resilient resistance of the holding rings, by engaging with a tool between the annular collar 27 and the annular cover plate 30, so as to lift the pin 31 out of the pocket 38 to effect a change of blade. WHAT WE CLAIM IS:-

1. A mowing machine comprising a rotatable cutting body having a lower end portion carrying cutting blades freely pivoted on pins so that the blades can swing out into a cutting position, said lower end portion including spaced upper and lower members, and the cutting blades are positioned in the space between said members, said pivot pins being carried on the under side of the upper member which is formed separately and which is flexibly supported from a further part of the cutting body for limited displacement relative to the lower member.

5. A mowing machine as claimed in any preceding claim in which the upper member has an outer marginal edge of a diameter which is substantially equal to or slightly smaller than the diameter of the outer marginal edge of the lower member

6. A mowing machine as claimed in any preceding claim in which the lower member is formed separately and is detachably conected to said further part of the cutting body via screw bolts engaging through spacer sleeves.

welded into a bore in the upper member and comprises a stop shoulder engaging under the threaded head of the pin.

16. A mowing machine as claimed in claim 15 in which the bearing notch has a width which is substantially equal to the distance between rhe under side of the tapped annular member and the top surface of the lower member.

17. A mowing machine substantially as hereinbefore described, with reference to the accompanying drawings.