The invention relates to a double action grab fork and to a method for using a double action grab fork. In particular, the grab fork is constructed to provide a rotation action and a lever action during use. The invention additionally relates to a grab fork teeth assembly that provides lateral stability.
Material handling vehicles such as front end loaders, tractor loaders, skid steer loaders, etc. generally have a pair of booms provided thereon to which various attachments are secured. Many material handling vehicles have a bucket attached to the booms to facilitate movement of material such as dirt, gravel, snow, feed, and wet materials. When the material handling vehicle is used for moving bales of hay, the bucket is often replaced with a grab fork attachment or a grab fork attachment is provided on the bucket. See U.S. Pat. No. 3,700,131 to Westendorf.
The invention is an improvement over prior grab fork attachments.
A double action grab fork is provided according to the invention. The double action grab fork includes an upper grab member, a lower grab member, and an arm. The upper grab member has an upper grab end and an upper grab body. The lower grab member has a lower grab end and a lower grab body. The upper grab end and the lower grab end are constructed for grasping an article. The arm has an upper end and a lower end. The upper end of the arm is rotatably attached to the upper grab body to allow rotation of the upper grab member relative to the upper end of the arm. The lower end of the arm is rotatably attached to the lower grab body to allow rotation of the lower grab body relative to the lower end of the arm.
The double action grab folk provides for a movement of the upper grab member relative to the lower grab member that can be considered as a first action or lever action and a second action or rotation action. The lever action is achieved by rotating the arm relative to the lower grab member. The rotation action is achieved by rotating the upper grab member relative to the arm.
A double action grab fork for use with a bucket on a front end loader is provided according to the invention. The double action grab fork assembly includes a grab teeth assembly, a frame assembly, a lever arm, and a rotation arm. The grab teeth assembly includes a teeth support constructed to rotate between a first position and a second position, and a plurality of teeth extending from the teeth support. The frame assembly includes a bucket fastener constructed for connecting the frame assembly to a bucket, and a frame assembly hydraulic cylinder connection for attaching the frame assembly to a hydraulic cylinder. The lever arm has a first lever arm end and a second lever arm end. The first lever arm end is rotatably attached to the teeth support, and the second lever arm end is rotatably attached to the frame assembly. The rotation arm has a first rotation arm end and a second rotation arm end. The first rotation arm end is attached to the teeth support, and the second rotation arm end includes a rotation arm hydraulic cylinder connection for attaching the rotation arm to a hydraulic cylinder.
The grab fork can include a hydraulic cylinder having a first hydraulic cylinder end and a second hydraulic cylinder end. When the grab fork includes a hydraulic cylinder, the first hydraulic cylinder end can be attached to the rotation arm hydraulic cylinder connection and the second hydraulic cylinder end can be attached to the frame assembly hydraulic cylinder connection.
A grab teeth assembly is provided according to the invention. The grab teeth assembly includes a teeth support and a plurality of teeth extending from the teeth support. The plurality of teeth include teeth formed from a pair of teeth members where each member has a first end and a second end. The first ends of the teeth members are attached together and the second ends of the teeth members are separated and attached to the teeth support. The attachments can be weld attachments.
A method for operating the double action grab fork is provided according to the invention. The method includes a step of extending the hydraulic cylinder to move the double action grab fork between an open position and a closed position. Retracting the hydraulic cylinder causes the double action grab fork to move between a closed position and an open position.
Referring to
The double action grab fork 10 includes an upper grab member 14 and a lower grab member 16. The upper grab member 14 and the lower grab member 16 are constructed to move relative to each other to allow the upper grab member 14 and the lower grab member 16 to grab and hold any item that will fit between the upper grab member 14 and the lower grab member 16 such as a bale of hay. The movement of the upper grab member 14 and the lower grab member 16 can be characterized as having a first action movement and a second action movement. The first action can be referred to as a lever action, and the second action can be referred to as a rotation action. By providing both the lever action and the rotation action, the upper grab member 14 can be characterized as being capable of reaching out and grabbing an item and pulling the item into the lower grab member 16.
The double action grab fork 10 can include any structure having the upper grab member 14 and the lower grab member 16, and providing for a first action movement and a second action movement. For the double action grab fork 10 shown in
The double action grab fork 10 includes an arm 22 having a first end 23 and a second end 24. The upper grab member 14 includes an upper grab end 15 and an upper grab body 19. The lower grab member 16 includes a lower grab end 17 and a lower grab body 21. The arm upper end 23 is rotatably attached to the lower grab body 19, and the arm lower end 24 is rotatably attached to the lower grab body 21.
The movement of the arm 22 relative to the lower grab member 16 can be characterized as a lever action of the upper grab member 14 relative to the lower grab member 16. The movement of the upper grab member 16 relative to the arm 22 can be characterized as a rotation action of the upper grab member 14 relative to the lower grab member 16.
The components of the upper grab member 14, the lower grab member 16, and the arm 22 are described in more detail in the context of the grab fork attachment assembly 18 and the bucket 20. The grab fork attachment assembly 18 can be constructed so that it fits onto any configuration of bucket. It should be understood that although a fairly common bucket configuration is shown by reference numeral 20, any bucket can be used in combination with the grab fork attachment assembly according to the invention.
Now referring to
It should be understood that
The grab teeth assembly 26 includes a teeth support 36 and a plurality of teeth 38 extending from the teeth support 36. The grab fork attachment assembly 18 can have a width that allows it to operate in combination with the bucket 20. In general, the width of the grab fork attachment assembly 18 can be about the same as the width of the bucket 20. It should be understood that the “width” refers to the distance from the left side to the right side. The view of the double action grab fork 10 shown in
The teeth support 36 extends across the width of the grab fork attachment assembly 18. The plurality of teeth 38 are provided along the teeth support 36 at spaced intervals. The teeth support 36 can be provided as a tube structure 40, and the plurality of teeth 38 can be attached thereto by welding. The plurality of teeth 38 can be provided having a shape that allows for wrapping around a cylindrical object such as a bale of hay. The shape of the plurality of teeth 38 can be described as arcuate when viewed from the side as shown in
The frame assembly 28 is provided for attaching the grab fork attachment assembly 18 to the bucket 20. The frame assembly 28 includes a support bracket 42, a bucket fastener 44, a frame assembly hydraulic cylinder connection 46, a frame assembly lever arm connection 48, and a cross member 49. Although not shown in
The support bracket 42 is constructed so that the grab fork attachment assembly 18 can have sufficient structural integrity when it is attached to the bucket 20 and can operate properly in conjunction with the bucket 20. The support bracket 42 can be constructed so that it fits over the bucket exterior surface 53. The bucket fastener 44 is shown having a first fastener location 50 and a second fastener location 52. The first fastener location 50 is provided for attaching the support bracket 42 to the bucket front side 54. The second fastener location 52 is provided for attaching the support bracket 42 to the bucket backside 56. The first fastener location 50 is provided as a pin 57 attached to the support bracket 42. The pin 57 engages a hook bracket 58 extending from the bucket front side 54. The second fastener location 52 includes a gap 60 in the support bracket. The gap 60 receives a pin 62 attached to the bucket backside 56. A retainer 64 can be fastened in place by the fasteners 66 to hold the pin 62 within the gap 60.
The lever arm 30 provides the grab fork attachment assembly 18 with a lever action when it moves between a first position 70 (as shown in
The movement of the lever arm 30 between the first lever position 70 and the second lever position 72 can be controlled by the lever arm stop 86 provided along the lever arm 30. The lever arm stop 86 includes a lever action stop 88 that controls the movement of the lever arm between the first lever arm position 70 and the second lever arm position 72 by engaging the lever restricting surface 90 provided along the support bracket edge 92. As shown in
The rotation of the teeth support 36 relative to the first lever arm end 74 can be referred to as the rotation action of the grab fork attachment assembly 18. The rotation action moves between a first position 78 (shown in
The rotation arm 32 includes a first rotation arm end 94 and a second rotation arm end 96. The first rotation arm end 94 attaches to the teeth support 36, and the second rotation arm end 96 includes a rotation arm hydraulic cylinder connection 98 for attaching the rotation arm 32 to the hydraulic cylinder 34. The first rotation arm end 94 can be welded to the teeth support 36. In addition, the rotation arm 32 includes a first rotation arm stop 100 and a second rotation arm stop 102. The first rotation arm stop 100 is provided so that it engages the rotation action stop 104 provided on the lever arm 30 when the grab fork attachment assembly 18 is provided in the first rotation arm position 78. Contact between the first rotation stop 100 and the rotation action stop 104 restricts opening of the grab teeth assembly 26. The second rotation arm stop 102 engages the rotation action stop 104 when the grab fork attachment assembly 18 is provided in the second rotation arm position 80. Contact between the second rotation arm stop 102 and the rotation action stop 104 restricts the movement of the grab teeth assembly 26 beyond the closed or second rotation arm position 80. Accordingly, the stops 100, 102, and 104 control the rotation of the grab teeth assembly 26 relative to the lever arm 30. It should be understood that the rotation arm 32 can be considered a part of the upper grab member 14 because of the attachment of the first rotation arm end 94 to the teeth support 36.
The hydraulic cylinder 34 includes a hydraulic cylinder first end 106 and a hydraulic cylinder second end 108. The hydraulic cylinder first end 106 attaches to the rotation arm 32 at the rotation arm hydraulic cylinder connection 98. The hydraulic cylinder second end 108 attaches to the frame assembly 28 at the frame assembly hydraulic cylinder connection 46. By extending the hydraulic cylinder 34, the first end 106 moves away from the second end 108. By retracting the hydraulic cylinder 34, the first end 106 moves toward the second end 108. The rotation arm hydraulic cylinder connection 98 and the frame assembly hydraulic cylinder connection 46 allow for rotation of the hydraulic cylinder 34.
As the hydraulic cylinder 34 extends, the lever action proceeds to move the grab fork attachment assembly 18 from the first lever arm position 70 to the second lever arm position 72. Once the second lever arm position 72 is achieved, the rotation arm action begins causing the grab fork attachment assembly 18 to move from the first rotation arm position 78 to the second rotation arm position 80. It should be understood that depending on the article that is being grabbed, the grab fork attachment assembly 18 may stop short of the second lever arm position 72 and/or the second rotation arm position 80. For example, a bale of hay may be sufficiently large in circumference to prevent the grab fork attachment assembly 18 from extending all the way to the second rotation arm position 80. When the hydraulic cylinder 34 is retracted, the movement of the grab fork attachment assembly 18 is reversed so that the rotation action precedes the lever action. As the hydraulic cylinder 34 is extended or contracted, the action or movement that is easiest precedes the action or movement that is more difficult. In the case of extending the hydraulic cylinder 34, the lever action precedes the rotation action in the configuration of the double action grab fork 10 shown in
The bucket 20 includes a left side wall 120, a back wall 122, a bottom wall 124, and a right wall (not shown). The bucket 20 includes bucket teeth 128 provided along the bucket leading edge 130. The bucket 20 has a general shape similar to many buckets commonly used and attached to material handling equipment. The bucket 20 has been modified to accept the grab fork attachment assembly 18. These modifications include the addition of the hook bracket 58 extending from the bucket front side 54, and the attachment of the pin 62 to the bucket backside 56. Exemplary bucket designs that can be used according to the invention include those bucket designs described in U.S. Pat. No. 6,374,520 to Westendorf et al. and U.S. patent application Ser. No. 09/639,039, the disclosures of which are incorporated herein by reference.
The assembly of the grab fork attachment assembly 18 and the bucket 20 is shown in
Once the grab fork attachment assembly 18 is attached to the bucket 20, the double action grab fork 10 is available for use. Disassembly of the double action grab fork 10 can be accomplished by placing the double action grab fork 10 in the position shown in
Although the double action grab fork 10 is disclosed in
An advantage of the double action grab fork according to the invention is that it allows the upper grab member to reach out and draw material back into the lower grab member. When the lower grab member is a bucket, the upper grab member can reach out and draw articles or material into the bucket. This double action provides an ability to conveniently clean out material from a bunker silo. With the double action grab fork fully open and the bucket bottom wall 124 flat on the ground (as shown in
Another advantage of the invention is that the first action and the second action can be controlled by a single lever. That is, the operator can use a single lever to cause the double action grab fork to move through the first action and then through the second action. The reason for this is that a single hydraulic cylinder (actually, a left hydraulic cylinder and a right hydraulic cylinder provided on the sides of the double action grab fork) causes the double action grab fork to move in both a first action and a second action. Accordingly, by controlling the hydraulic cylinder, the operator is able to control both the first action and the second action. In addition, the operator can use the same lever to cause the double action grab fork to reverse its motion and move through the second action and then through the first action.
The double action allows the operator to use the double action grab fork as a pincer. For example, the double action grab fork can be tilted so that it is facing downward, and then the double action grab fork can be used to pick up materials on the ground such as tree branches or broken bales.
Now referring to
The teeth 208 can be described as having a v-shape and being curved so that they provide a desired amount of strength against side pressure. The teeth can be designed out of two parts that are tapered toward the center. This allows for better penetration and maximum strength of the teeth. This also helps in covering more area when clamping and drawing into the bucket and to prevent material from falling out between the teeth.
As shown in
Now referring to
The above specification provides a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
Number | Name | Date | Kind |
---|---|---|---|
2326338 | Drott et al. | Aug 1943 | A |
2501243 | Snyder | Mar 1950 | A |
2812595 | Drott et al. | Nov 1957 | A |
3077999 | Svoboda | Feb 1963 | A |
3209474 | Artman | Oct 1965 | A |
3243905 | Ulrich | Apr 1966 | A |
3344540 | Ulrich | Oct 1967 | A |
3421642 | Carter | Jan 1969 | A |
3451575 | Petro | Jun 1969 | A |
3455477 | Blair | Jul 1969 | A |
3493134 | Ahrens | Feb 1970 | A |
3512665 | Westendorf | May 1970 | A |
3700131 | Westendorf | Oct 1972 | A |
3701443 | Lely | Oct 1972 | A |
3991890 | Frank | Nov 1976 | A |
4033469 | Frank | Jul 1977 | A |
4051962 | Westendorf | Oct 1977 | A |
4085856 | Westendorf | Apr 1978 | A |
4106646 | Weisgerber | Aug 1978 | A |
4345870 | Anderson et al. | Aug 1982 | A |
4538955 | Langenfeld et al. | Sep 1985 | A |
4565485 | Wilman | Jan 1986 | A |
4566844 | Campin | Jan 1986 | A |
4606692 | Langenfeld et al. | Aug 1986 | A |
4787811 | Langenfeld et al. | Nov 1988 | A |
4790084 | Anderson et al. | Dec 1988 | A |
4797051 | Langenfeld et al. | Jan 1989 | A |
4859130 | Langenfeld et al. | Aug 1989 | A |
4890400 | Long | Jan 1990 | A |
4915575 | Langenfeld et al. | Apr 1990 | A |
4925359 | Dunnegan | May 1990 | A |
4930974 | Langenfeld et al. | Jun 1990 | A |
4968213 | Langenfeld et al. | Nov 1990 | A |
4995760 | Probst et al. | Feb 1991 | A |
5121557 | Moore | Jun 1992 | A |
5314292 | Holopainen | May 1994 | A |
5466113 | Norberg | Nov 1995 | A |
5639205 | Kaczmarczyk et al. | Jun 1997 | A |
5797461 | Noble | Aug 1998 | A |
5957650 | Rollo | Sep 1999 | A |
5997237 | Langenfeld et al. | Dec 1999 | A |
6074160 | Brumbaugh et al. | Jun 2000 | A |
6109859 | Domann | Aug 2000 | A |
6142724 | Hirooka et al. | Nov 2000 | A |
6267547 | Lund | Jul 2001 | B1 |
6287072 | Wasilas | Sep 2001 | B1 |
6374520 | Westendorf et al. | Apr 2002 | B1 |
Number | Date | Country | |
---|---|---|---|
20030223852 A1 | Dec 2003 | US |