MACHINE FOR FORMING CYLINDRICAL BALES OF CROP

Abstract: A U-shaped bale push bar (54) straddles a discharge gate (34) of a large round baler (10) with opposite legs (56) of the bar being respectively pivotally connected to a pair of support brackets (52) which are secured to, and project rearwardly alongside, the discharge gate (34) from upper rear locations of opposite sidewall sections (20, 22) forming a portion (30) of the baler main frame (12). A pair of chains (68) is coupled between forward locations of the gate (34) and the legs (56) of the push bar (54) and the chains (68) serve as lost-motion connections that cause the push bar (54) to extend and retract respectively in following relationship to opening and closing movements of the gate (34) such that interference between the gate (34) and a discharged bale (28) is avoided. An over-centre spring assembly (90) acts between the push bar (54) and support brackets (52) to bias the bar (54) toward its re­ tracted (non-operative) position when the gate (34) is at an intermediate closing position at which the bale (28) cannot pass under the gate (34). The assembly (90) also acts to bias the push bar (54) toward its extended posi­ tion when the gate (34) is at an intermediate opening po­ sition permitting discharge of a bale. A shock absorber assembly (94) works against the energy of the over-centre spring assembly (90) to prevent sudden motion of the push bar (54).

Description: The present invention relates to a machine for forming cylindrical bales of crop having a forward portion, a rearward discharge gate vertically pivotally mounted on the forward portion for movement between a closed lowered position and an open raised position, a U-shaped bale push bar having a pair of legs joined by a push member and vertically pivotally mounted on the forward portion for movement between a non-operative position disposing the push member beneath the gate when the latter is completely closed and an extended position maintaining the bale clear of the gate's swing, and an actuator for causing the movement of the push bar from its non-operative to its extended positions and from its extended to its non-operative position. U.S. - A - 4,483,247 discloses a machine of the above type in which the bale ejector is used to ensure that, when discharged, the bale is kept clear of the gate so that it can close without fouling the bale. Specifically, the machine includes a bale-forming chamber having opposite ends defined by opposite sidewalls including forward portions forming part of a fixed main baler frame and rearward portions forming opposite sidewalls of a bale discharge gate which is mounted on an upper rear location of the fixed forward sidewall portions for swinging between a lowered closed positior and a raised open position in which a completed bale can be discharged from the chamber. A U-shaped bale push bar includes opposite legs connected by horizontal pivots to the fixed forward sidewall portions adjacent the pivotal connection of the discharged gate. A push member joins the legs and is located beneath a lower forward portion of the gate, when the latter is in a closed position. A first pair of extensible and retractable hydraulic actuators is connected between the baler main frame and discharge gate for swinging it. A second pair of extensible and retractable hydraulic actuators is connected between the baler main frame and the push bar for swinging the latter between a non-operative retracted position, wherein the push member is beneath a path traced by the discharge gate when the latter moves between its closed and open positions, and an extended position wherein the push member is rearward of that path. The push member swings in an arc which is radially outward of the arcuate path followed by the lowest part of the gate. The first and second hydraulic actuators are coupled in a hydraulic system including sequencing valving which ensures that the gate is completely open before the push bar moves a bale rearwardly and is completely closed before the push bar moves from its extended to its retracted position. While such a structure is effective in permitting the discharge of a bale without requiring the baler to be moved in order to avoid interference between a discharged bale and the discharge gate as the latter is closed, it is essential that the sequencing valves be operational and that their settings be correctly established and maintained to ensure that such interference is avoided. DE-A-3 247 661 discloses a machine for forming cylindrical bales of crop having a gate which can be raised into an open position to allow a completed bale to be discharged through the opening and a support for the completed bale which is swingable between a non-discharge position and a discharge position to form a ramp down which the bale can roll to the ground wherein suspension means, being coupled between the gate and the support such that the support can be swung to the discharge position on the raising gate pulling the suspension means. The present invention provides a simpler arrangement for a push bar requiring less precise attention to establish and maintain it in good function and avoids the need that the gate must be fully open or fully closed before movement of the push bar. According to the present invention the actuator comprises a lost motion linkage coupled between the gate and the bale push bar, so that the linkage transmits movement from the gate to the push bar only after the gate on being raised, has reached an intermediate opening position at which the bale can pass under the gate and on lowering has reached an intermediate closing position at which the bale is prevented from passing under the gate, and an over-centre spring assembly coupled between the legs of the push bar and the forward portion so as to bias the push bar away from its non-operative position when the gate is between its intermediate opening position and its open raised position. Such a mechanical arrangement can be simpler and its settings do not require the level of precision regarding establishment and maintenance as is needed with a hydraulic system such as that referred to above. The ejector can be moved after the intermediate opening position and the intermediate closing position of the gate without waiting for the gate to be fully opened or closed, thereby saving time. An embodiment of the invention will now be described with reference to the accompanying diagrammatic drawings in which: FIG. 1 is a front elevational view of a large round baler equipped with a push bar assembly and shows the discharge gate of the machine closed and the push bar in its retracted position; FIG. 2 is a right side elevational view of the baler shown in FIG. 1; FIG. 3 is a view like FIG. 2 but showing the discharge gate opened far enough to permit a bale to drop from the bale-forming chamber of the machine to the ground and showing the slack removed from a lost-motion effecting chain connected between the gate and push bar; FIG. 4 is a view like FIG. 2 but showing the gate fully open with the push bar fully extended and a shock absorber for the chain collapsed and acting as an up-stop for the push bar; FIG. 5 is a view like FIG. 2 but showing the gate in its closing cycle where the chain connecting the gate and push bar has just become taut whereby further gate movement will pull the push arm toward its retracted position; FIG. 6 is an enlarged portion of FIG. 2 showing the chain connection between the gate and push bar; and FIG. 7 is a front elevational view of the structure shown in FIG. 6. Referring now to the drawings, there is shown a baler 10 of the type for making large cylindrical bales and commonly called a large round baler. The baler 10 comprises a main fraim 12 supported on a pair of ground wheels 14, 16 and includes a forwardly projecting draft tongue. An expansible bale chamber is defined by opposite sidewalls 20 and 22 and a plurality of side-by-side belts 24 supported on a plurality of belt support and belt tensioning and take-up rolls (not shown) arranged, as disclosed in U.S. - A - 4,428,282 for defining an inlet in the bottom of the chamber for receiving crop delivered by a pickup 26 so that it can be rolled by action of the belts 24 into a completed bale 28. The sidewalls 20 and 22 are composed of a front section or forward portion 30 forming part of the main frame 12 and a rear section 32 forming part of a discharge gate 34, the sections 30 and 32 meeting at an approximately vertical transverse plane 36 when the gate 34 is closed, as shown in FIG. 2. The gate 34 is mounted on an upper rear location of the front section 30 by a structure 38 forming a transverse pivot axis about which the gate 34 is rearwardly and upwardly swingable to a raised, fully open position, as shown in FIG. 4. A pair of extensible and retractable hydraulic gate actuators 40 (only one shown) is mounted between the front section 30 and the gate 34 and serves to open and close the latter as desired. A bale push bar assembly or bale ejector 50 is mounted on the front section 30 of the baler for pushing and holding a discharged bale clear of the gate 34 as the latter is cycled between its closed and open positions. Specifically, the push bar assembly 50 includes a pair of support brackets 52 secured to upper rear locations of the sidewalls of the front section 30 and extending rearwardly alongside the opposite sidewalls of the gate 34. A U-shaped push bar 54 has opposite legs 56 joined at one end by a transverse bale push member 58 and having another end defined by a pair of spaced triangular plates 60 each of which have the rear end of one of the brackets 52 received therebetween and secured thereto by a pivot connection 62. The pivot connections 62 are coaxial and establish a horizontal transverse axis about which the push member 58 is swingable between a retracted or lowered stored position, disposing the push member 58 in a home position beneath the gate 34 when the latter is closed (FIG. 2) and an extended or raised position disposing the push member 58 rearwardly of a path travelled by a lower extremity of the gate as it moves from its closed to its fully open position (FIG. 4). The push member 58 is defined by a cylindrical metal rod core on which is received a friction reducing roller 65 for reducing the frictional drag imparted to the member by a bale engaged thereby, which results in an easier kick action. Preferably, the roller 65 is made of a plastic tube. A linkage 66 exhibiting a lost-motion characteristic is provided for establishing a connection between the gate 34 and the push bar 54 whereby opening and closing the gate 34 effects extension and retraction of the push bar 54, with such extension and retraction lagging the gate movement sufficiently to ensure a discharged bale pushed and held by the push bar does not interfere with the gate. The linkage 66 is defined by identical structure located at opposite sides of the baler and only that structure located at the right side of the baler is completely illustrated. Specifically, this structure includes a flexible elongate member in the form of a link chain 68 having its forward end defined by a link 70 respectively received on an outwardly projecting pin 72 fixed to a central forward location of the right sidewall of the gate 34. The rear end of the chain 68 is coupled to one end of a rod 74 forming part of a shock absorber 76. The rod 74 is slidably received in an eye 78 of a transverse eyebolt 80 that is swivelly mounted in the pair of triangular plates 60. A coil compression spring 82 is received on the rod 74 and compressed between an adjustable double nut assembly 84 at one end of the rod and the eye 78. To ensure the proper orientation of the shock absorber 76, a smaller eyebolt 86 extends crosswise through and is secured to an outwardly projecting end of the transverse eyebolt 80. Coupled between the pair of plates 60 and the eye of the eyebolt 86 is a tension spring 88. An over-centre spring assembly 90 is mounted between the pair of plates 60 of each leg of the push bar 54 and the adjacent bracket 52 and serves when on one side of centre to bias the push bar towards its retracted position and when on the other side of centre to bias the push bar towards its extended position. Specifically, each spring assembly 90 includes a tension spring 92 having its opposite ends connected to one of the brackets 52 and one of the pairs of plates 60 such that, when the gate 34 is closed, the spring is stretched and has its centre line passing close to but below the pivot axis established by the connections 62 of the push bar 54 to the brackets 52. Thus, the spring 92 then acts to bias the push bar 54 to its retracted position. It will be appreciated that only a small upward displacement of the push bar 54 is needed for moving the springs 92 over centre such that they bias the push bar 54 toward its extended position. However, during opening of the gate 34 no displacement of the push bar 54 will occur until the gate has swung far enough to tighten the chains 68, it being noted that upon initial movement of the gate 34 the chains 68 will slacken and be ineffective in transferring gate movement to the push bar. Normally the gate 34 will be opened only to discharge a bale in which case the action of the springs 92, when moved over centre to bias the push bar 54 to its extended position, will work against the resistance of the discharged bale. However, provided for cushioning the action of the springs 92 in the event that the gate 34 is opened when no bale is present to be discharged, or when upward movement of the push bar 54 is not being restrained by the chains 68 is a pair of shock absorbers 94 which may be of the gas or oil cylinder type. Each shock absorber 94 has one end coupled to one of the pairs of triangular plates 60 and another end coupled to an adjacent one of the brackets 52. The lines of centre of the shock absorbers 94 are located so as to be just above the connections 62 establishing the pivot axis of the push bar 54 when the latter is in its retracted position. Also, the shock absorbers 94 are arranged so that they become fully collapsed so as in effect to form a positive up-stop for the push bar 54 when the latter reaches its extended position. The push bar 54 may be deactivated by simply disconnecting the chains 68 from the discharge gate 34 and respectively reconnecting them to a pair of pins 96 fixed to the brackets 52. The reconnected chains 68 are tight and thus hold the push bar 54 in its retracted position. The operation of the push bar assembly 50 is briefly as follows. Assuming the baler 10 to contain a bale ready for discharge, the bale discharge gate 34 will be closed and the bale push bar 54 will be retracted. Discharge of the bale is then accomplished by effecting extension of the gate actuators 40 and opening of the gate 34. Initial movement of the gate 34 will result in the initially taut chains 68 going slack with no movement of the gate 34 being transferred to the push bar 54 until the gate has moved relative to the push bar a distance sufficient to retighten the chains 68 and is at an intermediate opening position (FIG. 3). By this time the bale will have dropped on the ground ahead of the transverse push member 58 of the push bar 54. Further movement of the gate 34 toward its fully open position once the chains 68 tighten, causes the push bar 54 to begin to extend. Initial movement of the push bar 54 moves the tension springs 92 over centre and they go from a condition biasing the push bar toward its retracted position to a condition biasing the push bar toward its extended position. The bale, because of its contact with the push member 58, will offer resistance to the action of the springs 92 and the push bar 54 will be extended only by action of the chains 68 as the gate 34 travels on to its fully open position. Should the gate 34 be opened when no bale is contained in the baler, the shock absorbers 94 act against the action of the springs 92 to slow the rate of movement of the push bar 54 that would otherwise occur. The push bar 54 is then holding, or at least positioned to hold, the discharged bale rearwardly of the path traced by the lowermost (when closed) portion of the gate 34 and the actuators 40 are then controlled to retract to return the gate 34 to its closed position. The tension springs 92 act to keep the push bar 54 extended until the gate 34 has moved sufficiently far once again to tighten the chains 68 (at an intermediate closing position - FIG. 5) to pull the push bar 54 back towards its retracted position. Just before the push bar 54 reaches its retracted position, the springs 92 will move over centre and act to bias the push bar 54 to its retracted position. The shock absorbers 94 will also dampen this movement. During the opening and closing of the gate 34, the shock absorbers 76 will act to prevent the chains 68 from being shock loaded when the gate pulls the chains from their slack to their tight conditions. Also, the effective length of the flexible members defined by the shock absorbers 76 and chains 68 can be adjusted to vary the distance a bale is pushed by adjusting the preload on the compression springs by tightening or loosening the double nut assembly 84, with tightening of the nuts shortening the effective length and loosening of the nuts lengthening the effective length. The tension springs 88 act to keep the shock absorbers 76 properly oriented so that they do not foul the chains 68 when the latter are slack. When the action of the push bar 54 is not desired, it may be deactivated by simply disconnecting the chains 68 from the gate 34 and reconnecting them to the pins 96 fixed to the brackets 52. The chains 68 then act to retain the push bar 54 in its retracted position whereby bales may be discharged without any interference thereby.

Claims: A machine for forming cylindrical bales of crop having a forward portion (30), a rearward discharge gate (34) vertically pivotally mounted on the forward portion (30) for movement between a closed lowered position and an open raised position, a U-shaped bale push bar (54) having a pair of legs (56) joined by a push member (58) and vertically pivotally mounted on the forward portion (30) for movement between a non-operative position disposing the push member (58) beneath the gate (34) when the latter is completely closed and an extended position maintaining the bale (28) clear of the gate's swing, and an actuator for causing the movement of the push bar (54) from its non-operative to its extended positions and from its extended to its non-operative position characterized in that the actuator comprises a lost motion linkage (66) coupled between the gate (34) and the bale push bar (54) so that the linkage (66) transmits movement from the gate (34) to the push bar (54) only after the gate (34) on being raised has reached an intermediate opening position at which the bale (28) can pass under the gate (34) and on lowering has reached an intermediate closing position at which the bale (28) is prevented from passing under the gate (34), and an over-centre spring assembly (90) coupled between the legs (56) of the push bar (54) and the forward portion (30) so as to bias the push bar (54) away from its non-operative position when the gate (34) is between its intermediate opening position and its open raised position. A machine according to claim 1 characterized in that the over centre-spring assembly (90) is connected between the legs (56) of the push bar (54) and the forward portion (30) so as to bias the push bar (54) towards its non-operative position when the gate (34) is between its intermediate closing position and its closed lowered position. A machine according to claim 1 characterized in that the said linkage (66) includes a flexible element (68) to provide the lost motion. A machine according to claim 3 characterized in that the flexible element comprises a chain (68). A machine according to claim 3 or 4 characterized in that the linkage (66) is adjustable to vary the amount of lost motion so as to vary the distance the push bar (54) travels from and to its non-operative position. A machine according to any preceding claim characterized in that the linkage (66) includes a shock absorber (76) connected to the flexible member (68) against shock-loading thereof. A machine according to claims 5 and 6 characterized in that the shock absorber (76) is adjustable to vary the said amount of lost motion. A machine according to claim 7 characterized in that a shock absorber (94) is connected between the legs (56) and the forward portion (30) for cushioning the movement of the push bar (54) by the over-centre spring assembly (90). A machine according to claim 8 characterized in that the shock absorber (94) is disposed so as to act as an up-stop for the push bar (54) A machine according to any of claims 8 to 9 characterized in that the push member (58) comprises a cylindrical rod and a friction-reducing tube (65) received thereon. A machine according to claim 10 characterized in that the tube (65) is of a plastics material. A machine according to any of claims 8 to 11 characterized in that the forward portion (30) includes a pair of brackets (52) extending rearwardly of the rest of the forward portion (30) and the legs (56) are pivotally mounted on the brackets (52). A machine according to claims 4 and 12 characterized in that a said chain (68) is connected between each leg (56) and the gate (34), and the over-centre spring assembly (90) comprises a spring (92) connected between each leg (56) and the corresponding bracket (52). A machine according to claims 6, 7 and 13 characterized in that the chains (68) are each connected to a respective said adjustable shock absorber (76) comprising a rod (74), a mount (80) slidably securing the rod (74) to the respective leg (56) or the gate (34), an abutment (84) carried by the rod (74) and adjustable therealong, and a coil spring (82) on the rod (74) compressible between the abutment (84) and the mount (80), the rod (74) being connected to a said chain (68) at its respective gate or leg end. A machine according to claim 14 characterized in that the gate ends of the chains (68) are disconnectible from the gate (34) and reconnectible to the forward portion (30 at locations such that the chains (68) retain the push bar (54) at its non-operative position throughout movement of the gate (34).

Inventors: ANSTEY, HENRY DENNIS, ARDUESER, WILLIAM ALBERT
Applicants: DEERE & COMPANY
Application year: 1988
Main classification: A01F15
IPC codes: A01F15