Pivot Pin Assembly for Shaker Head

Abstract

A pivot pin assembly for a tree shaker pivotally attaches the clamping arm to the stationary arm. Each end of the cylindrical pivot pin extends outside of a cylindrical bore of the clamping arm. A longitudinal load member extends through an aperture in the stationary arm and into an aperture in the cylindrical pivot pin. An axial load may be applied to the longitudinal load member which compresses a plate of the stationary arm against the cylindrical pivot pin, but without compressing the stationary arm against the clamping arm. This configuration allows substantial torque to be applied to the longitudinal load member, which reduces play between the stationary arm and the clamping arm without inhibiting the free rotation of the clamping arm. Application of this torque eliminates radial and vibratory movement in the shaker head, which otherwise cause damage to the components of the shaker head.

Claims

1. In a shaker head comprising a frame and clamping arm wherein the frame comprises an upper plate and a lower plate and the clamping arm is pivotally attached to the frame, wherein the clamping arm comprises a top surface and a bottom surface, and a first length is defined by the distance from the top surface to the bottom surface, a pivot pin assembly for pivotally attaching the clamping arm to the frame comprises: a cylindrical pivot pin having a first end and a second end where the cylindrical pivot pin extends through a top aperture in the top surface and the cylindrical pivot pin extends through a bottom aperture in the bottom surface, where a second length is defined by the distance from the first end to the second end, wherein the second length is greater than the first length; and a longitudinal load member which extends through an upper aperture in the upper plate and into a first aperture in the first end of the cylindrical pivot pin wherein application of an axial load in the longitudinal load member compresses the upper plate against the first end of the cylindrical pivot pin without compressing the clamping arm.

2. The pivot pin assembly of claim 1 wherein the first aperture extends through the cylindrical pivot pin from the first end to the second end.

3. The pivot pin assembly of claim 2 wherein the longitudinal load member extends through the cylindrical pivot pin from the first end to the second end.

4. The pivot pin assembly of claim 3 wherein the longitudinal load member comprises threads

5. The pivot pin assembly of claim 4 wherein the longitudinal load member comprises a nut made up on the threads.

6. The pivot pin assembly of claim 4 wherein the longitudinal load member comprises a hexagonal head.

7. The pivot pin assembly of claim 1 further comprising a second aperture in the second end of the cylindrical pivot pin wherein the first aperture and the second aperture are in axial alignment but do not penetrate through the cylindrical pivot pin.

8. The pivot pin assembly of claim 3 wherein the first aperture and the second aperture comprise a plurality of internal threads.

9. In a shaker head comprising a frame and clamping arm wherein the frame comprises an upper plate and a lower plate and the clamping arm is pivotally attached to the frame, wherein the clamping arm comprises a top surface and a bottom surface and a first length is defined by the distance from the top surface to the bottom surface, a pivot pin assembly for pivotally attaching the clamping arm to the frame comprises: a cylindrical pivot pin having a first end with a first threaded aperture where the cylindrical pivot pin extends through a top aperture in the top surface and the cylindrical pivot pin extends through a bottom aperture in the bottom surface, where a second length is defined by the distance from the first end to the second end, wherein the second length is greater than the first length; and a first threaded fastener which extends through an upper aperture in the the upper plate and makes up into the first threaded aperture wherein application of a first torque to the first threaded fastener compresses the upper plate against the first end of the cylindrical steel pin without compressing the top surface.

10. The pivot pin assembly of claim 9 wherein the cylindrical pivot pin comprises a second end with a second threaded aperture, and further comprising a second threaded fastener which extends through a lower aperture of the lower plate and makes up into the second threaded aperture wherein application of a second torque to the second threaded fastener compresses the lower plate against the second end of the cylindrical pivot pin without compressing the bottom surface.

11. The pivot pin assembly of claim 9 further comprising a first wear bushing disposed between the cylindrical pivot pin and the top aperture.

12. The pivot pin assembly of claim 10 further comprising a second wear bushing disposed between the cylindrical steel pin and the bottom plate aperture.

13. The pivot pin assembly of claim 11 wherein the clearance between the cylindrical pivot pin and the first wear bushing ranges from 2 to 4 thousandths of an inch.

14. The pivot pin assembly of claim 9 wherein the first torque is greater than 2,500 lb-ft.

15. The pivot pin assembly of claim 9 wherein the cylindrical pivot pin has a diameter greater than 3 inches.

16. The pivot pin assembly of claim 9 wherein the first threaded fastener has a diameter greater than 1 inch.

17. In a shaker head comprising a clamping arm and a stationary arm, wherein the clamping arm comprises a fixed end pivotally attached to the stationary arm, wherein the stationary arm is integral to a frame having a case structure comprising an upper plate and a lower plate, the upper plate and the lower plate in opposite facing relation, the upper plate having an upper plate aperture having an upper plate aperture diameter and the lower plate having a lower plate aperture having a lower plate aperture diameter, the clamping arm comprising a top surface and top surface aperture having a top surface aperture diameter, the clamping arm further comprising a bottom surface and a bottom surface aperture having a bottom surface aperture diameter, wherein the clamping arm is pivotally attached to the frame by a pivot pin assembly comprising: a cylindrical pivot pin having a cylindrical pivot pin diameter, the cylindrical pivot pin diameter larger than the upper plate aperture diameter and the lower plate aperture diameter but smaller than the top surface aperture diameter and the bottom surface aperture diameter, the cylindrical pivot pin further comprising a first end and a second end, the first end of the cylindrical pivot pin having a first end aperture wherein the cylindrical pivot pin is disposed into the top surface aperture with the first end extending above the top surface and the cylindrical pivot pin is disposed into the bottom surface aperture with the second end extending below the bottom surface; and a longitudinal load member which extends through the upper plate aperture and into the first end aperture wherein application of an axial load in the longitudinal load member compresses the upper plate against the first end of the cylindrical pivot pin without compressing the top surface. a second threaded fastener which extends through the lower aperture of the lower plate and makes up into the second set of threads of the second aperture.

18. The pivot pin assembly of claim 17 wherein application of a first torque to the first threaded fastener does not compress the top plate.

19. The pivot pin assembly of claim 17 wherein the top plate aperture is lined with a first wear bushing which is disposed between the cylindrical steel pin and the top plate aperture.

20. The pivot pin assembly of claim 19 wherein the clearance between the cylindrical pivot pin and the first wear bushing ranges from 2 to 4 thousandths of an inch.

21. The pivot pin assembly of claim 18 wherein the first torque is greater than 2,500 lb-ft.

22. The pivot pin assembly of claim 17 wherein the cylindrical pivot pin has a diameter greater than 3 inches.

23. The pivot pin assembly of claim 17 wherein the first threaded fastener has a diameter greater than 1 inch.

24. The pivot pin assembly of claim 17 wherein a first length is defined from the top surface to the bottom surface and a second length is defined from the first end to the second end, and the second length is greater than the first length.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 depicts a prior art shaker head.

[0021] FIG. 2 depicts a close-up view of a prior art pivot pin assembly utilized in the prior art shaker head depicted in FIG. 1.

[0022] FIG. 3 depicts a pivot pin utilized in a prior art shaker head.

[0023] FIG. 4 shows a side view of a shaker head in which an embodiment of the presently disclosed pivot pin assembly is utilized.

[0024] FIG. 5 shows a top view of the pivot pin assembly shown in FIG. 4.

[0025] FIG. 6 shows the clamping arm partially separated from the stationary arm of a shaker head.

[0026] FIG. 7 shows a close-up view of an embodiment of a pivot pin of the present invention.

[0027] FIG. 8 shows an embodiment pivot pin of the present invention of the type utilizing threaded fasteners which make up into threaded apertures at each end of the pivot pin.

[0028] FIG. 9 shows a top view of a portion of a shaker head frame, showing the top of an embodiment of the pivot pin assembly.

[0029] FIG. 10 shows a side view of a portion of a shaker head, showing an embodiment of the pivot pin placed between the upper plate and the lower plate of the shaker head frame and the relative position of the top plate and bottom plate of the clamping arm.

[0030] FIG. 11 shows a side view of a portion of a shaker head, showing the clamping arm and pivot pin separated from the shaker head frame.

[0031] FIG. 12 shows a side view of a portion of a shaker head with the pivot pin removed, where the pivot pin is attached by a load member which extends all of the way through the pivot pin.

[0032] FIG. 13 shows an embodiment of a load member having a threaded end and an integral head on the opposite end.

DETAILED DESCRIPTION OF THE INVENTION

[0033] Referring now to the figures, FIGS. 1 and 2 depict a known shaker head 100. A pivot pin 102 at the rear or pivot end 120 of a frame 130 attaches the clamping arm 104 to the frame 130. Frame 130 comprises a stationary arm 106 which may be either attached or integral to frame 130. Fixed end 112 of clamping arm 104 is typically sandwiched between opposing plates 116, 118 of the frame 130 as shown in FIGS. 1 and 2. The clamping arm 104 will typically have a housing 108 through which the pivot pin 102, typically having a 1¼ inch diameter shaft, is placed. The pivot pin 102 extends completely through the housing 108 and through the opposing plates 116, 118 of the stationary arm, with a pivot pin bushing 110 retaining each end of the pivot pin 102, typically with a bolt 122 set transversely through the pivot pin bushing 110 and pivot pin 102 to secure the pivot pin 102.

[0034] FIG. 3 shows pivot pin 102 removed from the shaker head 100. The pivot pin 102 from prior art shaker heads typically has a diameter of 1¼ inch. As FIG. 3 shows, the prior art pivot pin 102 comprises a solid shaft having threaded ends. If significant torque is applied to pivot pin 102 opposing plates 116, 118 will bind about fixed end 112 of the clamping arm 104 inhibiting its free rotation as clamping arm 104 is squeezed between the plates. However, the pivot pin bushing 110 in the pivot pin assembly depicted in FIGS. 2-3 is not configured to allow the application of any significant torque on pivot pin 102, so binding of the fixed end 112 of the clamping arm 104 is typically not a problem. However, because the existing systems allow flexing and movement of these various components as the shaker head 100 operates, the various shaker head components are subject to structural failure.

[0035] FIGS. 4-6 depict a portion of a shaker head 200 equipped with an embodiment of the present pivot pin assembly 10. The clamping arm 204 has a free end (not shown) and a fixed end 212, where the fixed end is attached to the pivot end 220 of the frame 230, so that clamping arm 204 may pivot towards stationary arm 206. The frame 230 may have case structure having an upper plate 216 and a lower plate 218, with the upper plate and the lower plate in opposite facing relation. The upper plate 216 has an upper aperture 232 extending through the upper plate. Likewise, the lower plate has a lower aperture, which is not shown, but is similar to the upper aperture 232 which extends through the lower plate 218, where the upper aperture 232 and the lower aperture are in opposite facing relation, and have the same internal diameter. Upper plate 216 and lower plate 218 may be fabricated from steel and will typically have a wall thickness of approximately ¾ inch each.

[0036] The fixed end 212 of the clamping arm 204 is pivotally attached at the pivot end 220 of the case structure 230 between the upper plate 216 and the lower plate 218. The fixed end 212 of the clamping arm 204 has an upper surface 236 and a lower surface 238. A pivot pin housing 208 is positioned between the upper surface 236 and the lower surface 238, where the pivot pin housing has a cylindrical bore 240 extending there through. The pivot pin assembly 10 has a cylindrical pivot pin 12 having a first end 14 and a second end 16. The cylindrical pivot pin 12 is sized to be disposed into the bore 240 of the cylindrical housing 208. The cylindrical pivot pin 12 has an outside diameter D which, particularly when compared with pivot pin 102 of FIG. 3, is substantially larger than the pivot pins 102 used in the prior art shaker heads 100. For example, in one embodiment of the present invention, the cylindrical pivot pin 12 may have a diameter D of 4½ inches. The cylindrical pivot pin 12 will have sufficient clearance with the inside walls of the bore 240 of the cylindrical housing 208 to allow rotation of the clamping arm 240 about the pivot pin, where pivot pin 12 does not rotate with respect to the ears 246, 248 in upper plate 216 and lower plate 218 of frame 230. A clearance between pivot pin 12 and bore 240 ranging from 2 to 4 thousandths is acceptable.

[0037] Pivot pin 12 is manufactured from high strength carbon steel. It has a first end 14 and a second end 16. In one embodiment, first end 14 of the pivot pin 12 has a first threaded aperture 18 while the second end 16 has a second threaded aperture 20. In another embodiment, pivot pin 12′ has a continuous aperture 18′ which extends axially from the first end 14′ to the second end 16′.

[0038] In any embodiment, the pivot pin 12 has a length L.sub.1 such that when the pivot pin 12 is disposed into the bore 240 of the cylindrical housing 208, the first end 14 extends above the upper surface 236 of the clamping arm 204 and the second end 16 extends below the lower surface 238 of the clamping arm, where the distance from upper surface 236 to lower surface 238 is L.sub.2, as illustrated in FIG. 11. In other words, L.sub.1 is always greater than L.sub.2. Pivot pin 12 is positioned between ears 246, 248 such that when an axial load is applied to the longitudinal load member or members which hold pivot pin 12 in place, the ears 246, 248 will be supported by pivot pin 12.

[0039] For the embodiment of pivot pin 12 having a first threaded aperture 18 in first end 14 and a second threaded aperture 20 in the second end 16, a first threaded fastener 22 extends through the upper aperture 232 of the upper plate 216 and makes up into first threaded aperture 18. Likewise, a second threaded fastener 24 extends through a lower aperture of the lower plate 218 and makes up into second threaded aperture 20. Application of torque to the first threaded fastener 22 compresses the ear 246 of upper plate 216 against the first end 14 of pivot pin 12 but does not compress the clamping arm 204. As with the first threaded fastener 22, application of torque to the second threaded fastener 24 compresses the ear 248 of the lower plate 218 against the second end 16 of pivot pin 12 without compressing the clamping arm 204. As a result, substantial torque may be applied to the fasteners 22, 24 which connect the clamping arm 204 to the stationary arm 206, where application of the torque reduces play between the clamping arm and stationary arm, but application of the torque does not inhibit the free rotation of the clamping arm 204 about the pivot pin 12, which remains stationary. The first threaded fastener 22 and the second threaded fastener 24 will generally have the same diameter as the pivot pins 102 currently in use, typically ranging from 1¼ to 1½ inch.

[0040] In another embodiment of the invention 10, the pivot pin 12′ may have a continuous aperture 18′ which extends through the longitudinal axis of the pivot pin from the first end 14′ to the second end 16′. In this embodiment, a longitudinal load member 22′ extends through the upper aperture 232 of the upper plate 216, through the continuous aperture 18′ and extends through a lower aperture of the lower plate 218. In this embodiment longitudinal load member 22′ will have a threaded end 30 to which end a nut 32 may be applied. The opposite end 32 of longitudinal load member 22′ may be threaded for receipt of a nut. Alternatively, end 32 may have other means for retaining it, such as a pin inserted through an aperture extending diametrically through an end of the longitudinal load member 22′, a welded washer or plate attached at one end of the longitudinal load member, a retaining clip or a taper bushing which attaches to an end of the longitudinal load member. Alternatively, one end or both ends of the longitudinal load member may have a threaded aperture which receives a threaded fastener. As with the embodiment of the pivot pin 12 described above, application of a load to the longitudinal load member 22′ compresses the ear 246 of upper plate 216 against the first end 14 of pivot pin 12′ but does not compress the clamping arm 204.

[0041] In another embodiment of the invention 10, a wear bushing 26 may be disposed between the pivot pin 12 and the bore 240 of the cylindrical housing 208. This wear bushing 26 will typically be fabricated from a softer material, such as brass, and will have a wall thickness ranging from ⅛ to ¼ inch. The wear bushing 26 will typically be press fit into the bore 240 of the cylindrical housing 208. A grease fitting 34 may be installed through cylindrical housing 208 to allow the placement of grease between the contact surfaces of the clamping arm 204, including wear bushing 26, and pivot pin 12.

[0042] Embodiments of the present invention may further comprise methods of attaching a clamping arm 204 to a stationary arm 206 of a tree shaker.

[0043] Having thus described the preferred embodiment of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following: