MXPA98006342A - Podad - Google Patents

Abstract

The present invention relates to a mower consisting of: a pruning head having a spring-loaded blade pivotally connected to the jaw about a pivot point, the jaw cooperating with the blade to cut a workpiece received in a bend formed by the jaw, a drive connected to the pruning head, the drive mechanism consists of a first wheel that can be rotated relative to this around a first axis and coupled with the blade by means of the line of the head, being connected to the first wheel at a connection point so that the line of the head is wound around a guide surface of the first wheel as the first wheel rotates about the first axis, the drive mechanism also consists of a second rotating wheel with the first wheel, the second wheel being coupled to a driving line, and an elongated box connected to the driving mechanism, wherein the first The wheel is eccentric relative to the second wheel so that a distance separating the first axis from a region of the guide surface where the head line stops coupling with the guide surface is smaller at a predetermined point in the travel of the head. the blade through the reco

Description

MOWER Field of the invention The present invention relates, in general, to the technique of cutting tools, and specifically to cutting devices such as pruners.

BACKGROUND OF THE INVENTION Pruning shears having a pair of elongate members disposed for cooperative coupling about a pivot joint are widely used. Each of these members generally consists of a jaw, usually made of stamped or forged metal or other suitable material, which has an opposite end for the application of the force connected to a handle. In the anvil-type mowers, one of the jaws is formed as a blade while the other jaw is configured as an anvil. The cutting of dense growth, such as the leaves of trees, in the order of 2 inches in diameter, requires considerable force. To provide additional leverage, pruning shears are usually provided with extra long handles. This configuation offers the user additional leverage necessary to perform the desired cutting operation, and the extended part reaches to cut off distant branches of the trees and the like.

Although these handles are often made of wood to reduce forearm fatigue, the most recent prior art mowers have included hollow handles made of fiberglass or other suitable material, as described in U.S. Patent No. 5,570,510 to of the present inventor. However, in certain cases some of these prior art mowers can still make handling relatively difficult, particularly in areas densely populated by branches of trees or plants to reach the leaves to be cut. This is because this population usually prevents the user from opening the handles as is necessary to place the blades (or blade and anvil) around the dense growth to be cut. In addition, the different components of these prior art mowers, which are usually exposed, are also susceptible to being trapped in areas of dense foliage. Some of these limitations have already been recognized and taken into account by those skilled in the art. U.S. Patent No. 5,020,222 to Gosselin discloses a compound action mower in which an additional lever member connected to one of the jaws increases the shear force transmitted to the jaws, thereby facilitating the cutting operation. The additional leverage is also provided by a device devised by the present inventor and described in the pending United States Patent Application No. 08-702,122 filed on August 20, 1996. As illustrated in Figure IA, those skilled in the art of the cut of trees they have realized that the resistance the court denominated like F that in general presents the fibrous and round growth, as for example, a thick branch of tree L, is not uniform but varies as a function of the penetration of the B cutting blade in growth. The maximum resistance is usually reached at a point P approximately 60% through the useful stroke. This is because, up to this point, the penetrating action of the blade B on the branch L results in the compression of an increasing number of fibers as the blade B penetrates more into the branch L, thereby increasing the density of the blade. the thick branch L. As shown in Figure 1, C represents the compression region of the fibers of the branch L, while F represents the frictional forces opposing the shear force applied by a user. Beyond the point P which is the point of the maximum compression of the fibers, the resistance to the shearing action decreases as the blade begins to cut the fibers (as illustrated in the S region, where the growth begins to be separated and , as a result, the resistance to the cutting action yields until the branch L is completely separated). Therefore, it is advantageous that a cutting tool is provided with a variable force mechanism that provides maximum leverage at the point in the useful stroke corresponding to the maximum resistance for cutting. Although mowers of the type described above adequately provide the desired additional leverage to perform the desired cutting function, it can be readily apparent that in certain cases their use can still be made difficult by the dense foliage surrounding a branch that is going away. shorten. Accordingly, it seems desirable to provide a mower that can overcome the problems associated with conventional aspects of this class, ie, that are more compact in use to facilitate certain delimbing operations.

SUMMARY OF THE INVENTION The present invention provides a particularly advantageous variable force cutting mechanism that is constructed to generate maximum mechanical advantage (ie, maximum leverage) at the most desirable point through the useful stroke, however, unduly increasing the total weight of the scissors. As a result, the mower according to the present invention is designed to facilitate the care of plant trees and the like, specifically in areas congested by dense foliage. In accordance with one aspect of the invention, the mower includes a pruning head provided with a spring-biased blade cooperating with a jaw, a drive mechanism and an elongate housing (or housing). The driving mechanism includes the first and second wheels that can rotate relative to this around a first axis. A head line couples the first wheel to the blade at a connection point. The first wheel is eccentric relative to the second wheel to increase the leverage at a predetermined point of travel of the blade through the bend. According to another aspect of the invention, the blade includes an arm that extends outwardly from the pivot point, the arm being configured to further increase the mechanical advantage provided by the cam at the predetermined point of travel of the blade through the blade. bend. According to another aspect of the invention, the mower is provided with a pair of selectively actuable handles to move the blade relative to the jaw. According to still another aspect of the invention, the drive includes a pair of coupling portions and an indexing means for relatively positioning the blade with respect to the elongated box. Other advantages of the present invention will be apparent from the detailed description that is provided below. It should be understood, however, that the detailed description and specific embodiments are provided by way of illustration only since, from this detailed description, various changes and modifications within the spirit and scope of the invention will be apparent to the experts in The technique.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred exemplary embodiment of the present invention hereinafter will be described with reference to the accompanying drawings. Where equal numbers determine equal elements, and: Figure IA shows, in schematic form, the penetration of an important blade into a growth, illustrating the point at which the maximum resistance to the cutting action is usually reached; Figure 1 is an elevation view of the mower of the present invention, the mower blade is shown open relative to the jaw; Figure 2 is a right side elevational view of the mower of Figure 1; Figure 3 is a partial cut-away view of the pruning head and drive of the mower of the present invention, shown in the open position of the blade; Figure 4 is a partial front elevational view of the pruning head and drive of the mower of the present invention, as shown in Figure 3; Figure 5 is a partial cross-sectional view of the pruning head and drive of the mower of the present invention, shown with the blade occupied with a workpiece; Figure 6 is a partial front elevational view of the pruning head and drive of the mower of the present invention, as shown in Figure 5; Figure 7 is a partial cross-sectional view of the pruning head and drive of the mower of the present invention, shown with the blade in approximately half of its travel through the recode- Figure 8 is a front view partial elevation of the pruning head and drive of the mower of the present invention, as shown in Figure 7; Figure 9 is a cross-sectional view taken along the line 9-9 shown in Figure 3; Figure 10 is a cross-sectional view taken along line 10-10 shown in Figure 3; Figure 11 is a cross-sectional view taken along line 11-11 shown in Figure 5; Figure 12 is a partial cross-sectional view of the mower drive of the present invention, shown with the blade at the end of its travel through the bend; Figure 13 is a front elevation view of a portion of the elongated box of the mower of the present invention, the box being associated with the intermediate and lower handles; Figure 14 is a front elevation view of a portion of the elongated box of Figure 13 shown with the intermediate handle actuated; Figure 15 is a front elevational view of a portion of the elongated box of Figure 13 shown with the lower handle actuated; Figure 16 is a partial cross-sectional view of the pruning head and drive of the mower of the present invention, shown with the pruning head rotated relative to the elongated box; Figure 17 is a partial cross-sectional view of the mower drive of the present invention showing two coupling portions of the drive mechanism; Figure 18 is a cross-sectional view taken along line 18-18 as shown in Figure 17, illustrating a portion of a constant take-up region; Figure 19 is a cross-sectional view taken along line 19-19 as shown in Figure 17, illustrating a portion of a constant take-up region; and Figure 20 is a cross-sectional view taken along line 20-20 shown in Figure 17, illustrating the regions of constant take-up of the two coupling portions of the drive mechanism.

Detailed description of a preferred exemplary embodiment The present invention relates to cutting tools such as pruners. However, while the invention as described herein will often refer to a trimmer, those skilled in the art will appreciate that the mechanism described herein and its operating principles can be broadly applied to a wide variety of other cutting implements. . With reference to the Figures, a tool or pruner, generally designated as 10 for performing pruning, delimbing and cutting operations, includes a pruning head 12, an elongated box 14 and a driving mechanism 16 placed intermediate to the head 12 and the box 14 The pruning head 12 includes a blade 18 pivotable around a pivot point 19, and cooperating with a jaw 20 forming a bend or sine 22 configured to receive a workpiece 20 that is to be separated by the blade 18. spring 26 pushes the blade 18 to the open position relative to the jaw 20. Returning now to the drive mechanism 16, the drive mechanism 16 is advantageously connected to the pruning head 12 having a portion 18 of the mechanism 16 fused in the jaw 20. The mechanism 16 includes a first rotary wheel 30 with respect to the mechanism 16 around a first axis 32. The first wheel 30 is coupled to the blade 18 by a cable of the head 34 (for example). example, by means of a pin 35). As shown in the figures, the head cable 34 is preferably a chain. Those skilled in the art will nevertheless readily appreciate that a rope, cable or belt can also be used suitably for the line of the head 34. An end 36 of the line of the head 34 is connected to the first wheel 30 at a point of connection 38. The other end 40 of the line of the head 34 is connected to a region 42 of an arm 44 of the blade 18 extending outwardly of the pivot 19. As more specifically shown in the Figures 9 and 17, the driving mechanism 16 also includes a second wheel 46 that is rotatable with the first wheel 30. The second wheel 46 is coupled to a driving line 48. As shown in Figures 3, 5, 7, 9, 12 , 16 and 17, the first wheel 30 is eccentric relative to the second wheel 46, thereby causing an increase in the force applied to the workpiece 24 at a predetermined point of travel of the blade 18, as will be explained to continuation. To increase the flexibility of the mower 10, the drive mechanism 16 is formed of two coupling portions 50, 52 that can be rotated selectively one with respect to the other around the first axis 32. This allows the positioning of the mower head 12 relative to the elongated box 14. However, to increase the retention of the position of the pruning head 12 selected by the user, the coupling portions 50, 52 include an indexing means, generally designated as 54. As shown in Figures 18-20, the indexing means 54 includes the constant picking regions 56, 58 formed on the opposite surface facing each other 57, 59 of the coupling portions 50, 52. The regions preferably constant take include a plurality of teeth 60 which can be grouped into discontinuous segments. Otherwise, the teeth 60 may be the cinching portions 50, 52. Likewise, other inter-engagement structures such as, for example, index fingers or the like may be used instead. Accordingly, when the user wishes to reposition the pruning head 12 relative to the elongated box 14, the user will simply loosen the nut 62 sufficient to decouple the constant take-up regions 56, 58, and then rotate the coupling portions 50. , 52 one in relation to the other. Upon reaching the desired position of the head 12, the user will bring the coupling portions 50, 52 together so that the regions 56, 58 are re-engaged. This new position of the head 12 will be maintained by tightening the nut 62 on the head screw 64. Now returning to the elongated box 14, the box 14 is preferably hollow and teardrop shaped as shown in Figures 10 and 11 A sliding block 66 is slidably received within an inner region 68 of the box 14. The sliding block 66, which engages with the second wheel 46 by the driving line 48, engages by driving the line 70 passing over a pulley 72. The actuating line 70 is connected with an intermediate handle 74 which is slidable relative to the case 14. A viewed end 76 of the actuating line 70 is preferably connected to a lower handle 78 which is clisable with a lower end 80 of the case 14. It should be noted that the rotation of the pruning head 12 relative to the case 12 will slightly displace the location of the intermediate handle 74 along the case 14. However, the intermediate handle 74 it can easily be repositioned along the case 14 by adjusting the location of the handle 74 on the actuating line 70. The case 14 also includes a retainer 82 formed therein so that a pulling force exerted on the line of the head 34 by the blade pushed by the spring 18 causes the tension of the driving line 70 and also causes the intermediate handle 70 to abut against the stop 82. Therefore, it can be understood that a user can alternatively operate the handle intermediate 74 or the lower handle 78 for causing the blade 18 to travel through the bend 22. In particular, when the intermediate handle 74 is pulled down by the user, the lower handle 78 engages with the lower end 80 of the box 14 and the sliding block 66 is dragged downwardly within the region 68. On the contrary, when the lower handle 78 is pulled down, the intermediate handle 74 engages with the detent 82 and the b slider 66 is dragged downwardly within region 68. The eccentric configuration function of the first wheel 30 relative to the second wheel 46 will now be explained with more specific reference to Figures 7, 9 and 17. The first wheel 30 includes a guide surface 82 around which the line of the head 34 is wound as the first wheel 30 rotates about the first axis 32. In the same way, the second wheel 46 includes a second surface guide 84 around which the driving line 48 is wound as the second wheel 46 rotates with the first wheel 30. Because the first wheel 30 is eccentric on the first axis 32, the guide surface 82 is also eccentric relative to the first axis 32 and in relation to the second guide surface 84. The eccentric construction as described above causes a distance to separate the first axis 32 from a region 86 of the guide surface 82 where the line of the head 34 stops engaging with the guide surface 32 being smaller at a predetermined point of travel of the blade 18 through the bend 22. As is well known in the art, work is required to separate the workpiece jo 24 received at bend 22. It is also known that the work applied to the work piece is equal to the work applied by a user minus the losses through the transmission mechanism. Without considering the losses in the transmission, the work applied by the user by downward movement of the intermediate handle 74 or the lower handle 78 is transmitted from the second wheel 46 to the first wheel 30 as the two wheels rotate together. Consistent with well-known principles, the work on the first wheel 30 (which is then applied to the line of the head 34) is equal to the product of the distance separating the first axis 32 from the line of the head 34 by the force Ft transmitted to the line of the head 34 in the direction of the line of the head 34. As can be easily appreciated (and again neglecting the losses) since the work is constant, at the point where the distance separating the first axis 32 from the line of the head 34 reaches a minimum, the force Ft reaches a maximum. In other words, due to the eccentricity of the wheels 30 relative to the wheel 46, in the region of the guide surface 82 where the line of the head 34 stops coupling with the guide surface 32, the force Ft reaches a maximum due to to the fact that the distance separating the first axis 32 from the line of the head 34 is smaller. According to the present invention, the configuration of the first and second wheels 30, 46 relative to the path of the blade 18 minimizes the distance at the predetermined point P by falling to approximately 60% of the useful stroke, allowing for this means that the mower 10 generates the maximum leverage at this point, which is the point of the useful stroke where the density of the work piece 24 is higher. Taken from the same principles, to further increase the force applied to the work piece 24 at the point P, the arm 44 of the blade 18 is constructed relative to the cutting edge 88 of the blade 18 so that at the point P , as more specifically shown in Figure 8, the arm 44 will be substantially perpendicular to the line of the head 34. As a result, the entire Ft, (contrary to the only portion thereof when the line of the head 34 makes an angle with the arm 44) will be transmitted to the workpiece 24. It will be understood that the foregoing description is of a preferred exemplary embodiment of the present invention, and that the invention is not limited to the specific embodiments described. For example, while the invention has been described related to a device that takes the form of a mower, it can be used with other articles as well. In addition, the elongated box and the sliding block can take other forms as long as they can be associated, and that the box is configured to support the drive mechanism. Also, the first and second wheels may have other configurations while retaining their essential function as described above. However, it should be understood that these and other substitutions, modifications, changes and omissions can be made in the design and arrangement of the elements described herein without departing from the scope of the appended claims.

Claims (22)

1. A mower consisting of: a pruning head having a spring-loaded blade pivotally connected to the jaw about a pivot point, the jaw cooperating with the blade to cut a work piece received in a bend formed by the gag; a driving mechanism connected to the pruning head, the driving mechanism consists of a first wheel that can be rotated relative to it around a first axis and coupled with the blade by means of the line of the head, being connected to the first wheel at a connection point so that the line of the head wraps around a guide surface of the first wheel as the first wheel rotates about the first axis, the driving mechanism also consists of a second wheel rotating with the first wheel; the second wheel being coupled to a driving line; and an elongated box connected to the drive mechanism; wherein the first wheel is eccentric relative to the second wheel so that a distance separating the first axis from a region of the guide surface where the head line stops coupling with the guide surface is smaller at a predetermined point of the travel of the blade through the bend.

The mower of claim 1, wherein the blade includes an arm extending away from the pivot point, the arm being configured so that the arm and head line are substantially perpendicular at the predetermined point.

The mower of claim 1, wherein the head line and the drive line are selected from the group consisting of a chain, cable, rope and a band.

The mower of claim 1, wherein the first wheel is configured so that the predetermined point is approximately 60% of the travel of the substance through the bend.

The mower of claim 1, wherein the drive mechanism is selectively rotatable relative to the elongate housing about the first axis.

The mower of claim 5, wherein the drive mechanism further consists of a pair of coupling portions and an indexing means for relative positioning of the blade with respect to the elongate box.

The mower of claim 6, wherein the indexing means consists of constant tapping regions formed on opposite surfaces facing each other of the coupling portions.

The mower of claim 7, wherein the constant tap regions follow the coupling portions.

The mower of claim 1, wherein the box is tear-shaped.

The mower of claim 1, wherein the elongate box is substantially hollow and the mower further contains a sliding block slidably received within an interior region of the box, and an actuating line substantially received inside the box and attached to this, the sliding block being coupled with the second wheel by the driving line, the sliding block being coupled by the acting line so that the actuation of the acting line causes the pivoting movement of the blade relative to the jaw.

The mower of claim 10, wherein the sliding block includes a pulley guiding the acting line therethrough.

The mower of claim 10, wherein the actuating line is selected from the group consisting of a belt, rope and cable.

13. The mower of claim 10, wherein the actuating line joins an outer region of the box.

The mower of claim 1, wherein the elongated box is substantially hollow and the mower further contains a sliding block coupled with the second wheel by a drive line, the sliding block being slidably received within the inner region of the wheel. box and coupled by an acting line connected to a sliding intermediate handle relative to the box, the acting line being tensioned by a force exerted on the line of the head by the blade pushed by spring.

15. The mower of claim 14, further includes a retainer formed in the elongated box, the force causing the intermediate handle to abut against the retainer when the blade is opened relative to the jaw.

16. The mower of claim 15 further includes a lower handle attached at one end of the actuating line, the lower handle engageable with a lower end of the elongated box so that the blade can be rotated relative to the jaw by the Actuation of the intermediate handle or the lower handle.

17. A mower consisting of: a hollow elongated box; a drive connected to the elongated box; and a pruning head connected to the driving mechanism, the pruning head with a spring-biased blade cooperating with a jaw for cutting a workpiece received in a bend formed by the jaw, the blade being pivotable about a pivot point with the drive of a line of the head that connects the blade with the drive mechanism; wherein the driving mechanism consists of the first and second rotating wheels in relation to this around a first axis, the second wheel being coupled with the driving line, the line of the head being connected to the first wheel at a connection point so that the line of the head wraps around a guide surface of the first wheel as the first wheel rotates about the first axis, and the first wheel being eccentric relative to the second wheel so that a distance separating the first axis from a region of the guide surface where the line of the head stops coupling with the guide surface, is smaller at a predetermined point of travel of the blade through the bend.

18. The mower of claim 17, wherein the blade includes an arm extending away from the pivot point, the arm being disposed relative to the cutting edge of the blade so that the arm and head line are substantially perpendicular to the blade. the default point.

The mower of claim 17, wherein the pruning head is indexable relative to the elongated box.

20. A mower consisting of: a pruning head having a spring-biased blade pivotally connected to a jaw about a pivot point, the jaw cooperating with the blade to cut a workpiece received at the bend formed by the jaw; a driving mechanism connected with the pruning head, the driving mechanism consists of a first rotary wheel in relation to it around a first axis and coupled with the blade by a line of the head, the head line being connected to the first wheel in a connection point, the drive also contains a second rotating wheel with the first wheel; the second wheel being coupled with a driving line; an elongated box connected to the drive mechanism; and the means for imparting a variable shear force to the work piece as the blade travels through the bend.

The mower of claim 20, wherein the means imparting the force consists of the first wheel having a guiding surface around which the line of the head is wound as the first wheel rotates about the first axis, and the second wheel having a second guide surface around which the driving line is wound as the second wheel rotates with the first wheel, the guide surface being eccentric relative to the second guide surface so that a distance separating the first axis from a region of the guide surface where the line of the head stops coupling with the guide surface, is smaller at a predetermined point of travel of the blade through the bend.

22. The mower of claim 20, wherein the pruning head is indexable with respect to the elongated head.