GB1601981A

GB1601981A - Implement

Info

Publication number: GB1601981A
Application number: GB17332/78A
Authority: GB
Original assignee: C Van der Lely NV
Current assignee: C Van der Lely NV
Priority date: 1977-05-02
Filing date: 1978-05-02
Publication date: 1981-11-04
Also published as: FR2389315A1; NL7704769A; IT7822913A0; IT1095710B; DE2819103A1; GB1601982A

Description

(54) IMPROVEMENTS IN OR RELATING TO AN IMPLEMENT (71) We, C. VAN DER LELY N.V., of 10, Weverskade, Maasland, The Netherlands, a Dutch Limited Liability Company, do hereby declare the invention, for which 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 and by the following statement: This invention relates to a soil cultivating implement.

According to the present invention there is provided a soil cultivating implement comprising a frame to which a working member is rigidly connected, during normal operation, by a shear pin coupling comprising a first coupling member and a second coupling member, the first coupling member having a cylindrical outer surface disposed coaxially within a cylindrical bore of the second coupling member, and the shear pin being disposed substantially wholly within the space bounded by the interface between the two coupling members, advancement means being provided for moving the shear pin, after fracture, to re-establish rigid connection between the working member and the frame.

For a better understanding of the present invention and to shown how it may be carried into effect, reference will now be made, by way of exemple only, to the accompanying drawings, in which: Figure 1 is a side elevation of an agricultural implement attached to a tractor; Figure 2 is an enlarged partly sectional plane view taken on the line Il-Il in Figure 1; Figure 3 is a sectional view taken on the line Ill-Ill in Figure 2; and Figure 4 is a partly sectional view taken on the line IV-lV in Figure 3.

The agricultural implement shown in Figure 1 is a reversible plough 1. The reversible plough 1 is hitched by a three-point trestle 2 to the three-point lifting device 3 of a tractor 4. The reversible plough 1 comprises a plough beam 5 which extends substantially horizontally in operation, as shown in the side elevation of Figure 1, and is at an angle of about 60 to the intended direction of operative travel, indicated by an arrow A.

The plough beam 5 can be turned about a horizontal axis 6 with the aid of a control mechanism 7 arranged on the rear of the three-point hitch 2. By means of the control mechanism 7 the plough beam 5 can be set in either one of two positions offset from each other by about 180 . On the side of the plough beam 5 there are two pairs of operative parts formed by plough bodies 10, 11 and 12, 13 respectively, having carriers 8 and 9 respectively. As shown in the side elevation of Figure 1, the plough bodies 10 and 12 are in the underlying position and the plough bodies 11 and 13 are in overlying position. The carriers 8 and 9 extend rearwardly, and are preferably some distance from the plough beam 5 in a substantially horizontal direction; they are parallel to the direction A. Since the plough beam 5 is inclined to the direction A, the plough bodies are fastened by the carriers 8 and 9 to the plough beam 5 so that the operative plough bodies are relatively off-set in fact, but cooperate with one another during operation.

The plough bodies 10 and 11 located above the other are interconnected by a tie element 14, which is connected with the carrier 8, this connection being reinforced by tie plates 15.

The same applies to the plough bodies 12 and 13, which are connected with the carrier 9 by means of a tie element 16 and tie plates 17.

The carrier 8 is connected at the front by bolts 18 with arm 19 which extends forwardly for some distance. The arm 19 has upper and lower flanges 20, the arm 19 and the flanges 20 terminating near the plough beam 5 in a hub 21 having a substantially cylindrical inner bore centred on a pivotal axis 22 which is substantially horizontal and substantially perpendicular to the direction A. Coaxially within the hub 21 is disposed a cylindrical stub shaft 23 which has, on the end near the plough beam 5, an outwardly directed flange 24, by which the stub shaft 23 is fastened by bolts 26 to a support 25. The smallest diameter of the stub shaft 23 preferably exceeds the largest cross-sectional area of the carrier 8 and 9 respectively. The support 25 comprises, as shown in the sectional view of Figure 2, an angle member having two limbs which are substantially perpendicular to one another and are connected with the plough beam 5. One limb extends in the direction A, and the other is perpendicular to it. Between the outer wall of the stub shaft 23, which constitutes a first coupling member, and the inner wall of the hub 22, which constitutes a second coupling member, there is an annular opening 27 filled with lubricant for reducing friction between the contacting surfaces of the hub 22 and the stub shaft 23. In a direction parallel to the axis 22, the hub 21 is locked axially with respect to the plough beam 5 and the stub shaft 23 by retaining plates 28 and 29 which are arranged on the lower and upper sides respectively of the stub shaft 23 and are secured by bolts 30 at widened parts of the hollow stub shaft 23.

The hollow space inside the stub shaft 23 is divided by a transverse partition 32 into two spaces, this partition being located about two thirds of the way along the stub shaft from the support 25, measured in a direction parallel to the axis 22. The face of the partition 31 away from the support 25 constitutes the inner boundary of an outwardly opening space 32. The space 32 accommodates a supporting plate 33, which has two outwardly extending tags 34, which have, substantially midway along their length, a slightly recessed part 35. By means of the tags 34, a shear pin holder 36 is secured in the space 32. The shear pin holder 36 has a cylindrical inner surface and has on its outer surface two lugs 37 which co-operate with the recessed parts 35 of the tags 34 to secure the holder 36 in place. Together with the lugs 37, the tags 34 and the parts 35 provide a quick-action locking means or bayonet connection for the holder 36. In the holder 36 there is a compression spring 38 which engages at one end the closed end of the holder 36 and at the other end a pressure pin 39. Acting through the pressure pin 39, the spring 38 presses a shear pin 40 towards the wall of the hub 21. The centreline of the shear pin 40 intersects the pivotal axis 22 and extends, in normal operation, parallel to the longitudinal axis of the carrier 8 or 9 respectively. The movement of the shear pin 40 inside the space 32 is limited by the boundary face between the two coupling members 21 and 23. The shear pin has in its unused state a length of preferably more than 10 cms. The shear pin is locally weakened by equispaced grooves 41. The shear pin shown in Figure 4 has portions 42 which can break off successively more than 10 times, preferably 11 times, in the event of overload. In normal operation the endmost portion 42 is located in an opening 43 in the hub 21. The opening 43 is bounded by a hardened sleeve 44, which is connected with the hub 21. The shear pin 40 is guided through the stub shaft 23 in a close fitting hardened steel sleeve 45 which is arranged in a region of the wall of the stub shaft 23, which wall portion is preferably reinforced. The hub 21 has, as shown in the elevational view of Figure 3, a slightly smaller diameter on either side along arcs of about 90 so that a groove 46 is formed. The groove 46 is bounded on the side of the arm 19 by end faces 47. The stub shaft 23 is connected on the side away from the plough beam 5 with a pin stop member 48 which limits the movement of the pin 40 and has, preferably, a substantially U-shaped form with two limbs, one of which is connected to the stub shaft 23 and the other of which engages the endmost shear pin portion 42. The end of the pin stop member 48 is preferably pointed. This end part is otherwise located in the opening 43.

In an analogous manner the carrier 9 is connected by means of shear pin coupling with the plough beam 5.

The construction described above operates as follows.

During operation the reversible plough 1 is pulled along by the tractor 4 in the direction of the arrow A, and the plough bodies 10 and 12 loosen the earth beneath the ground surface and displace it. In normal operation the carriers 8 and 9 are connected rigidly with the plough beam 5 by means of the shear pin 40 of the shear pin coupling comprising the first coupling member constituted by the stub shaft 23 and the second coupling member constituted by the hub 21.

The endmost portion 42 of the shear pin 40 is located in the opening 43 in the sleeve 44.

The shear pin is pressed by the compression spring 38 towards the pin stop member 48.

Since the spring exerts pressure on the closed end of the shear pin holder 36, this holder is urged away from the pin stop member 48 against the tags 34, and so the lugs 37 engage the recessed parts 35 to give a satisfactory and rapidly operable bayonet connection.

This situation of normal operation continues as long as the resistance on the plough does not exceed a predetermined value, which is determined by the choice of the strength of the shear pin 40. If the plough resistance exceeds the chosen value, for example, when the mouldboard is subjected to an excessively high resistance due to a stone in the soil, the respective plough body 10 or 12 tends to turn upwardly in the direction of the arrow B in Figure 4 about the axis 22. This turn can be performed only after the end portion 42 of the shear pin has broken off when the maximum permissible force is exceeded.

Thus the plough body can travel past the object causing this excessive force by rotation of the hub 21 about the stub shaft 23, which rotation is facilitated by the presence of lubricant in the annular opening 27. The groove 46 permits the two coupling members to pivot through an arc of in total about 180 .

This pivotal movement of the two coupling members is limited by the co-operation between the stops 47 and the pin stop member 48. Owing to this movability the plough body can rise to the ground surface.

During the movement the opening 43 comes out from under the pin stop member 48 so that the broken off shear pin portion 42 can drop out of the opening. Subsequently the tractor driver can raise the entire implement using the lifting device 3 so that, owing to the weight of the plough bodies, the hub 21 will turn about the stub shaft 23 in a direction opposite the arrow B. Under the action of the spring 38 the part remaining of the pin 40 is slipped into the opening 43 so that the shear pin 40 gets into a new connecting position.

The same pin 40 can break and re-establish the connection upon overload more than ten times. After the shear pin has been fully consumed, the holder can be simply removed from the space 32 by moving the holder towards the pin stop member 48 and by turning it about its longitudinal axis through about 45 so that the lugs 37 are disengaged from the tags 34. The holder 36 can be filled with a new shear pin 40 and be simply and rapidly but back into the space 42 using the bayonet connection provided by the tags 34 and the lugs 37, so that the operation of the implement can be resumed after a very short time. In view of soiling and risk of damage it is advantageous for the holder to be located, as shown, in the space 32 enclosed by the stub shaft 23; the cylindrical boundary surface between the hub 21 and the stub shaft 23 has a diameter of about 20 cms. With the plough beam 5 turned about the shaft 6 so that the plough bodies 11 and 14 are operative, these plough bodies are protected against overload in an identical manner.

The implement disclosed herein is also disclosed and claimed in out copending patent application No. 8031064 (Serial No.

1601982).

WHAT WE CLAIM IS:- 1. A soil cultivating implement comprising a frame to which a working member is rigidly connected, during normal operation, by a shear pin coupling comprising a first coupling member and a second coupling member, the first coupling member having a cylindrical outer surface disposed coaxially within a cylindrical bore of the second coupling member, and the shear pin being disposed substantially wholly within the space bounded by the interface between the two coupling members, advancement means being provided for moving the shear pin, after fracture, to re-establish rigid connection between the working member and the frame.

2. An implement as claimed in claim 1, in which the first coupling member comprises a stub shaft.

3. An implement as claimed in claim 2, in which most of the shear pin is disposed within the periphery of the stub shaft.

4. An implement as claimed in claim 2 or 3, in which the centreline of the shear pin intersects the centreline of the stub shaft.

5. An implement as claimed in any one of claims 2 to 4, in which the two coupling members are pivotable to a limited extent relatively to each other about their common axis after fracture of the shear pin.

6. An implement as claimed in claim 5, in which the pivotal movement is limited by a stop member, which also limits the advancement of the shear pin.

7. An implement as claimed in claim 5 or 6, in which the two coupling members are pivotable relatively to each other through about 90 in two directions from an operative position.

8. An implement as claimed in any one of claims 5 to 7, in which, during normal operation, the pivotal axis is perpendicular to the intended direction of operative travel of the implement and is substantially horizontal.

9. An implement as claimed in any one of the preceding claims, in which there is provided an opening for lubricant at the interface between the two coupling members.

10. An implement as claimed in any one of the preceding claims, in which the shear pin comprises a plurality of shear pin portions separated by grooves.

11. An implement as claimed in ny one of the preceding claims, in which, in normal operation, a portion of the shear pin is disposed in an opening, and in which, after fracture, the opening is uncovered to allow the portion of the shear pin in the opening to be discharged.

12. An implement as claimed in any one of the preceding claims, in which the two coupling members are secured against axial movement relative to one another.

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Claims

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

groove 46 permits the two coupling members to pivot through an arc of in total about 180 .

This pivotal movement of the two coupling members is limited by the co-operation between the stops 47 and the pin stop member 48. Owing to this movability the plough body can rise to the ground surface.

During the movement the opening 43 comes out from under the pin stop member 48 so that the broken off shear pin portion 42 can drop out of the opening. Subsequently the tractor driver can raise the entire implement using the lifting device 3 so that, owing to the weight of the plough bodies, the hub 21 will turn about the stub shaft 23 in a direction opposite the arrow B. Under the action of the spring 38 the part remaining of the pin 40 is slipped into the opening 43 so that the shear pin 40 gets into a new connecting position.

The same pin 40 can break and re-establish the connection upon overload more than ten times. After the shear pin has been fully consumed, the holder can be simply removed from the space 32 by moving the holder towards the pin stop member 48 and by turning it about its longitudinal axis through about 45 so that the lugs 37 are disengaged from the tags 34. The holder 36 can be filled with a new shear pin 40 and be simply and rapidly but back into the space 42 using the bayonet connection provided by the tags 34 and the lugs 37, so that the operation of the implement can be resumed after a very short time. In view of soiling and risk of damage it is advantageous for the holder to be located, as shown, in the space 32 enclosed by the stub shaft 23; the cylindrical boundary surface between the hub 21 and the stub shaft 23 has a diameter of about 20 cms. With the plough beam 5 turned about the shaft 6 so that the plough bodies 11 and 14 are operative, these plough bodies are protected against overload in an identical manner.

The implement disclosed herein is also disclosed and claimed in out copending patent application No. 8031064 (Serial No.

1601982).

WHAT WE CLAIM IS:- 1. A soil cultivating implement comprising a frame to which a working member is rigidly connected, during normal operation, by a shear pin coupling comprising a first coupling member and a second coupling member, the first coupling member having a cylindrical outer surface disposed coaxially within a cylindrical bore of the second coupling member, and the shear pin being disposed substantially wholly within the space bounded by the interface between the two coupling members, advancement means being provided for moving the shear pin, after fracture, to re-establish rigid connection between the working member and the frame.
2. An implement as claimed in claim 1, in which the first coupling member comprises a stub shaft.
3. An implement as claimed in claim 2, in which most of the shear pin is disposed within the periphery of the stub shaft.
4. An implement as claimed in claim 2 or 3, in which the centreline of the shear pin intersects the centreline of the stub shaft.
5. An implement as claimed in any one of claims 2 to 4, in which the two coupling members are pivotable to a limited extent relatively to each other about their common axis after fracture of the shear pin.
6. An implement as claimed in claim 5, in which the pivotal movement is limited by a stop member, which also limits the advancement of the shear pin.
7. An implement as claimed in claim 5 or 6, in which the two coupling members are pivotable relatively to each other through about 90 in two directions from an operative position.
8. An implement as claimed in any one of claims 5 to 7, in which, during normal operation, the pivotal axis is perpendicular to the intended direction of operative travel of the implement and is substantially horizontal.
9. An implement as claimed in any one of the preceding claims, in which there is provided an opening for lubricant at the interface between the two coupling members.
10. An implement as claimed in any one of the preceding claims, in which the shear pin comprises a plurality of shear pin portions separated by grooves.
11. An implement as claimed in ny one of the preceding claims, in which, in normal operation, a portion of the shear pin is disposed in an opening, and in which, after fracture, the opening is uncovered to allow the portion of the shear pin in the opening to be discharged.
12. An implement as claimed in any one of the preceding claims, in which the two coupling members are secured against axial movement relative to one another.