The present invention relates generally to a machine for sharpening a point on wooden stakes, and, more particularly, to an apparatus that receives a supply of unsharpened wooden stakes and automatically forms a sharpened point thereon.
Wooden stakes are driven into the ground for a plurality of purposes, including fencing support, agricultural crop support, and survey and grade markers in construction. The stakes are formed on a cutting machine that forms the wooden stake in the required dimensions, whereupon the formed wooden blank is then transferred to another machine to form a point at one end to facilitate the driving of the stake into the ground. A number of different machines have been devised to form the sharpened point. Such machines are typically configured to move the wooden stake blank into the path of a cutting or chipping device that cuts away the wood along an angular path to form the customary point.
Such machines can be manually operated, as can be seen in U.S. Pat. No. 3,111,971, issued to Elbert Spencer on Nov. 26, 1963, in which a post blank can be inserted into a receiving tube into engagement with an angularly oriented chipping head that cuts away the wooden material at the end of the post to create a point thereon. In U.S. Pat. No. 5,109,896, issued to Christopher Tomes on May 5, 1992, and in U.S. Pat. No. 5,638,877, granted to Norman Apr. on Jun. 17, 1997, the wooden stake blank is manually inserted against a guide fence or tube into engagement with a chipping head to form the sharpened point, wherein the guide fence or tube is positioned at an angular orientation to the chipping head.
Wooden posts are also presented to machines to affect the sharpening of an end thereof, as can be seen in U.S. Pat. No. 3,073,362, granted to Simon Bourdon on Jan. 15, 1963, and in U.S. Pat. No. 3,403,710, granted to Richard Garrison on Oct. 1, 1968, in which the wooden post blank is manually presented into a conical chipping head to remove the wooden material at one end of the wooden post blank to form a point thereon. In U.S. Pat. No. 3,451,449, issued to Harold Bouma on Jun. 24, 1969, the wooden post blank is reciprocally moved into engagement with a conical cutterhead at each respective end of the machine to form a point and a cap at the opposite ends of the wooden post. Similarly, the machine disclosed in U.S. Pat. No. 4,387,751, granted to Charles Carter on Jun. 14, 1983, forms a point of wooden pickets by moving the picket blank into engagement with an abrading apparatus to remove the material at the end of the wooden picket blank.
The stake point machine disclosed in U.S. Pat. No. 3,190,325, granted to Elmer Mood on Jun. 22, 1965, operates a little differently in that the wooden stake blanks are aligned on a horizontal conveyor and clamped into a fixed position while a shearing head moves vertically into engagement with the wooden stake blank to sever wooden material away from the stake blank to form the point. The shearing head moves in conjunction with a V-shaped striker to affect the shearing of the material away from the stake blank. The conveyor advances sequentially to move the stake blanks into alignment with the striker member to be sheared into a point.
Presently commercially available stake pointing machine operate on a reciprocal basis to move a wooden stake blank into engagement with a cutting or chipping apparatus to form the point at the end of the stake. As can be seen in the know prior art references described above, the stakes can be manually handled to affect the sharpening process or in an automated manner in which the stake is clamped or fixed against a support and then moved into engagement with the cutting or chipping apparatus.
Such complex reciprocation equipment for the stake requires frames, clamping supports and linear actuators to affect the reciprocal movement of the stakes. It would be desirable to provide a less complex and less expensive stake pointing apparatus for use in industry to provide mass quantities of sharpened wooden stakes in an automated fashion.
It is an object of this invention to provide a machine for forming a point on wooden stakes that clamps the wooden stake blank and moves the cutting apparatus into engagement with the clamped wooden stake blank.
It is a further object of this invention to provide an effective automated process for sharpening wooden stakes.
It is a feature of this invention that the stake pointing machine can perform an automated sharpening of wooden stakes with a minimal number of moving parts.
It is as advantage of this invention that the stake sharpening machine can be manufactured at less cost than heretofore known in the industry.
It is another feature of this invention that the cutting head operable to form a point on the wooden stake is move into engagement with the wooden stake blank clamped on the support table.
It is still another feature of this invention that a walking beam transports the sharpened wooden stakes to a stacking apparatus for removal from the stake sharpening machine.
It is yet another feature of this invention that the primary drive apparatus causes a coordinated movement of the clamping apparatus, the movement of the cutting apparatus, and the movement of the conveying apparatus to affect a sharpening of wooden stakes in a sequential manner.
It is another advantage of this invention that the cutting apparatus is adjustably mounted on a subframe to permit positional movement thereof to accommodate different sized wooden stake blanks.
It is still another advantage of this invention that the cutting apparatus is formed with a conical chipping head that is moved axially into engagement with a wooden stake blank to affect sharpening thereof.
It is yet another feature of this invention that the walking beam conveyor sequentially moves the wooden stakes from a supply bin, to the sharpening station and to a remote collection area for stacking and shipping the sharpened wooden stakes.
It is still another feature of this invention that a switch engaged by the moving subframe supporting the cutting apparatus automatically trips actuation of a pneumatic or hydraulic cylinder to cause the clamping apparatus to engage the wooded stake blank before being engaged by the cutting apparatus.
It is yet another object of this invention to provide a wooden stake sharpening apparatus that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use.
These and other objects, features and advantages are accomplished according to the instant invention by providing a wooden stake sharpening apparatus in which the conical cutting head is moved linearly along a path into engagement with a clamped wooden stake blank to affect sharpening thereof. A walking beam conveying apparatus moves a wooden stake blank into position from a supply bin where a clamping apparatus holds the stake blank in place while the cutting head moves onto the stake to form a point thereon. The drive mechanism moves the conveyor in coordination with the linear movement of the cutting apparatus, which trips a switch to actuate the clamping mechanism as the cutting head moves toward engagement with the stake blank. The conveyor then moves the sharpened stake toward a collection area while moving another stake blank into position for sharpening as the cutting apparatus is retracted away from the stake, thus providing an automated stake sharpening machine with a minimal number of moving parts.
The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention.
a is a schematic representation of the walking beam conveyor demonstrating the operation of the conveyor;
b is a schematic representation of the walking beam conveyor depicting the lifting of an object from the base member to move the object up the base member;
c is a schematic representation of the walking beam conveyor depicting the operation of the conveyor to push an object positioned on the delivery table;
d is a schematic representation of the walking beam conveyor showing the return of the waling beam to be positioned beneath the positions depicted in
Referring to
The walking beam conveyor 20 is best depicted in
As is best seen in the schematic diagrams of
The continued rotational movement of the conveyor fins 26 ultimately reaches the position of the fin 37 in phantom lines in
Continued rotation of the drive apparatus 29 progresses the sharpened stake up the base member fins 23 one saw tooth stop 24 at a time until the sharpened stake reaches the delivery table 25. As can be seen in the conveyor fin 37 in phantom in
The cutterhead 40 is formed as a conical chipping device 42 into which a stake blank can be inserted axially to obtain the formation of a point on the end of the stake, not wholly unlike the operation of a conventional pencil sharpened. The conical chipping device 42 is operably connected to a motor 45, preferably an electric motor that is operable to generate sufficient power to chip wood away from the stake blanks in a rapid manner for efficient production. The cutterhead 40 is reciprocally mounted on linear rails 46 for movement toward and away from the base member 22. Preferably, the electric motor 45 moves with the chipping device 42 in reciprocating toward and away from the stake blank with wires (not shown) delivering electrical current thereto being mounted in a conventional manner to allow for the reciprocating movement.
The position of the rails 46 is selectively movable to affect a precise positioning of the open throat of the chipping device 42. More particularly, a vertical movement of the rails 46, and thus the cutterhead 40 can be accomplished through manipulation of the adjustment lever 47 and the accompanying linkage supporting the linear rails 46 and the cutter head 40. Similarly, the horizontal alignment of the cutterhead 40 can be accomplished through the selective manipulation of the adjustment lever 48. By appropriate utilization of the position adjustment levers 47, 48, the throat of the chipping device 42 can be properly positioned and repositioned to correspond to differently sized wooden stake blanks so that the throat of the chipping device 42 is properly aligned with the stake blank, irrespective of the dimensions thereof.
A clamping apparatus 50 is pivotally mounted next to the reciprocating cutterhead 40 to restrain the wooden stake blank in place on the lowermost saw tooth stops 24c on the base member fins 23 while the chipping device 42 is advanced into engagement with the unsharpened end of the stake blanks. The clamping apparatus 50 is formed as a rock shaft 52 rotationally mounted on the frame 11 of the machine 10. Projecting from the rock shaft 52 toward the cutterhead 40 are a pair of clamp arms 53 that have mounted on the distal ends thereof a length of angle iron forming the clamping member 55 that is movable into engagement with a stake, as will be described in greater detail below. An actuator arm 56 projects from the rock shaft 52 away from the cutterhead 40 for engagement with a linear actuator 57, such as, preferably, a pneumatic cylinder or a hydraulic cylinder. The stroke of the linear actuator 57 can be varied in known manners to selectively locate the clamping position of the clamping member 45 to correspond to differently sized stakes being sharpened. The linear actuator 57 is operatively powered through an appropriate supply of air under pressure, or to a hydraulic system (not shown) providing hydraulic fluid under pressure to the actuator 57 for operation thereof.
A trip switch 59 is position on the adjacent rail 46 for the cutterhead 40 so that any movement of the cutterhead 40 into engagement with the trip switch 59 triggers the actuation of the linear actuator 57 in response to the movement of the cutterhead 40 along the rails 46. For example, a forward movement of the cutterhead 40 along the slide rails 46 trips the switch 59 to cause an extension of the actuator 57 causing the actuator arm 56 to raise and a corresponding rotation of the rock shaft 52. This rotational movement of the rock shaft 52, in turn, causes the clamping arms 53 to move downwardly, driving the clamping member 55 into a clamping engagement of the stake positioned on a support table, which preferably may also be the lowermost saw tooth stop 24c on the base members 23.
After sharpening the end of the clamped stake, the cutterhead 40 is reciprocated away from the stake just sharpened, again tripping the switch 59 to cause the linear actuator 57 to contract. This contraction of the linear actuator 57 causes a lowering of the actuator arm 56, and a resultant raising of the clamping member 55 to release the sharpened stake for movement up the conveyor apparatus 20 as described above. Thus, the clamping of the stake blank to resist the forces asserted on the stake blank by the rotating chipping device 42 is automatically initiated in response to the cutterhead 40 moving toward the stake blank for engagement thereof.
The drive mechanism 60 is best seen in
The second output from the gear box 63 is a crank 65 that rotates at the same rotational speed as the first output rotating the conveyor fins 26. The crank 65 is connected via a pivoted connecting arm 67 to the cutterhead 40 to cause reciprocal linear movement of the cutterhead 40 along the rails 46 as the crank 65 is rotated by the electric motor 62. Thus, the reciprocating movement of the cutterhead 40 is timely to the operation of the conveyor fins 26, as will be described in detail below. The operative power for operating the movable components of the machine 10 are delivered by the electrical motor 45 driving the rotation of the chipping device 42, the electrical motor 62 driving the cyclical motion of the conveyor 20 and the cutterhead 40, and the linear actuator 57, preferably a pneumatic cylinder, driving the operation of the clamping apparatus 50. As one of ordinary skill in the art will recognize, the stake sharpening machine 10 is constructed in a simple manner with a minimal number of moving parts that will provide an automated process for the sharpening of stake blanks.
Looking at all of the drawings, but particularly to the schematic representations in
Continued movement of the drive mechanism 60 pulls the cutterhead 40 along the rails 46 into engagement with the trip switch 59, which initiates the expansion of the linear actuator 57 and the resultant clamping of the stake blank B against the lowermost saw tooth stop 24c on the base member fins 23, as is depicted in
As the drive mechanism 60 cycles the conveyor fins 26 through the lower part of the drive cycle from the position 37 through to the position 39 and then position 31, the crank 65 pulls the chipping device 42 into engagement with the stake blank B and then away from the now sharpened stake S, as is shown in
The cycle is repeated with each revolution of the drive mechanism 60, moving each sharpened stake S upwardly along the base member fins 23 until reaching the delivery table 25 where the sharpened stakes can be collected for shipment or further handled by stacking and packaging machinery (not shown). At full capacity, the machine 10 is capable of sharpening up many stake blanks per hour, while providing an automated process that requires only a single operator to load stake blanks into the supply bin 15 and to remove sharpened stakes from the delivery table 25.
The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below.
Number | Name | Date | Kind |
---|---|---|---|
2170687 | Johnson | Aug 1939 | A |
3073362 | Bourdon | Jan 1963 | A |
3111971 | Spencer | Nov 1963 | A |
3190325 | Mood | Jun 1965 | A |
3403710 | Garrison | Oct 1968 | A |
3451449 | Bouma | Jun 1969 | A |
3719216 | Tracy | Mar 1973 | A |
4100949 | Carter | Jul 1978 | A |
4238983 | Westmoreland | Dec 1980 | A |
4387751 | Carter | Jun 1983 | A |
5109896 | Tomes | May 1992 | A |
5343911 | Humphrey | Sep 1994 | A |
5638877 | April | Jun 1997 | A |
6364093 | LaBolt | Apr 2002 | B1 |
6817392 | Phillips | Nov 2004 | B2 |
7093628 | Kelly et al. | Aug 2006 | B2 |