MXPA96005843A - Piv manual tools - Google Patents

Abstract

The present invention relates to a manual pivot tool having a longitudinal axis, characterized in that it comprises a pair of opposed first and second elongate members, each member having a jaw at a front end portion thereof, a handle at a rear portion of the same, and a middle portion where the members cross one over the other, a pivot that joins the middle portions of the elongated members for the movement in the form of scissors of the handles and the jaws around the pivot, the handle of the first The elongated member rotates about an axis of rotation substantially parallel to the longitudinal axis when the jaws are closed, and transmission means for converting a rotational force applied to the first handle to a rectilinear force joining the grippers.

Description

MANUAL PIVOT TOOLS CftflPQ PE Lfl INVENTION The present invention relates generally to manual cutting tools, particularly to pruning shears.

BACKGROUND OF THE INVENTION Pivot implements having elongate members arranged for cooperative engagement on a pivotable joint are widely used. In particular, pivot tools such as pruning shears generally comprise two elongated members, typically made of die-cut or forged metal or other suitable material, arranged for cooperative engagement on the pivotable joint. Typically, each member includes a jaw in the front outer portion thereof, an opposite tail, and a pair of lugs connected to the tails. In the case of conventional manual pivot tools such as scissors, pruners or tongs, the fingers initially apply an alternating force perpendicular to the surface of the upper handle. Afterwards, during the movement in the form of scissors of the handles, the fingers rotate in the direction of destruction near the lower handle, thus reducing the force used to join the handles and increase the kinetic friction. The kinetic friction that results from the sliding of the fingers near the handle creates discomfort to the user and reduces the efficiency of the mower. It is also known that, in tools for cutting such as carriers, a relatively strong impact occurs at the end of the cutting movement when the resistance presented by the piece being cut is reduced. Attempts have been made to give the problem of kinetic friction a greater user comfort. For example, in the Swiss mower Felco 1? A lower handle, against which the user's fingers intend to be placed, is rotatable near its longitudinal axis. As a result, the fingers do not slide on the surface of the handle during the cutting movement but the handle rotates with the fingers during the cutting movement. However, because the handle moves very easily, the grip on the handle feels loose and uncontrollable. In addition, the fact that the handle is rotatable does not reduce the strong impact at the end of the cutting movement. Thus, it seems desirable to provide a pivot tool such as pruning shears or the like that allow a firm and comfortable fastener, and wherein the force applied by the jaws to the piece being cut increases compared to prior art tools. .

BRIEF DESCRIPTION OF THE INVENTION The present invention increases the output force of a pair of scissors for pruning or similar hand-cutting tools (i.e., the force applied to the piece being cut), by interconverting a rotational force imparted to one of the handles in a rectilinear force The force that in conventional tools has been worn due to the kinetic friction between the fingers and the handle, and that can be quite large when a lot of effort is used, is now added to the force with which the user tightens the nearest handles a of the other In other words, the present invention utilizes the rotational movement imparted to the handle rotatable by the user's fingers to increase the shear force applied by the jaws to the article being cut. In addition, the fact that the rotation of one of the handles joins both handles also improves the user's control of the tool, and reduces the impact at the end of the cutting movement of the tool. A manual pivot tool according to the invention comprises a pair of opposed first and second elongated members, each member having a jaw at a front end portion thereof, a handle at a rear portion thereof, and a middle portion where The members pass over each other. The handle of the first Elongated member is rotabie around an axis of rotation. A pivot joins the middle portions of the opposed elongated members for movement in the form of scissors of the lugs and the jaws around the pivot. A transmission mechanism inter-converts a force to plicada to The handle rotatable in a rectilinear force that joins the handles. In accordance with one aspect of the invention, the transmission mechanism comprises an elongate flexible element and a groove formed in the handle gi abie at a distance from the axis of rotation of the handle. Part of the flexible element is received in the slot when the lugs are joined. In accordance with a preferred embodiment of the present invention, the transmission mechanism includes a rack and pinion arrangement in which a pinion formed in the pivotable handle alternates with a rack formed in the other handle of the pivot tool. Other advantages of the invention will be apparent from the detailed description given below. It should be understood, however, that the detailed description and specific embodiments are given by way of illustration only because, from this detailed description, various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art. in the technique.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred exemplary embodiment of the invention will hereinafter be described in conjunction with the accompanying drawings, in which like numerals denote similar elements and: Figure 1 is a front elevational view of pruning shears according to the invention, shown in FIG. the closed position; Figure 2 is a front elevational view of the pruning shears of Figure L, shown in the open position; Figure 3 is a bottom plan view of the pruning shears of Figure 1; Figure 4 is a rear elevation view of the pruning shears shown in Figure 1; Figure 5 is a rear elevational view of the pruning shears shown in FIG. Figure 6 is a flat top view of the pruning shears of Figure 4; Figure 7 is a later elevation view of the pruning shears of Figure 2, shown from the free end of the lugs; Figure 8 is a side elevational view of the pruning shears of Figure 1, showing from the free end of the lugs; Figure 9 is a rear elevational view of another embodiment of the pruning shears according to the invention; Figure 10 is a view in elevation later-al as in Figure 7 showing the different vector-applied forces in the pruning shears; Figure 11 is a side elevational view of the Felco 12 mower, viewed from the free end of the lugs in the open position, and showing the vector forces applied to the mower; Figure 12 is a VLSta in lateral elevation of a conventional pruning scissors with non-rotatable handles, seen from the free end of the handles in the open position, and showing the vector forces applied; Fig. 13 is a diagram of the vector forces applied by the user's fingers to the pruning shears of Fig. 2; Figure 14 is a side elevation view as in Figure 10 illustrating the rotation of the lower handle; Figure 15 is a diagram of the transmission of forces by the rotating handle: DFS DETAILED REFERENCE OF A PREFERRED EXAMPLE MODE The invention relates to a pivoting tool having elongate members arranged for cooperative coupling around a pivotable joint wherein a force applied to the handles of the tool is transmitted to the jaws that adjust a work piece that is going to cut. Referring to the figures, a carrier 10 in accordance with the invention includes first and second elongated members 12 and 14, respectively, attached for scissor action about a pivot tip 28. The first elongated member 12 includes a jaw 16 in the The shape of a cutting blade in a front end portion 17 of the same, a handle 18 in a rear end portion 19, and a portion 20 of intermediate jaw 16 and handle 18. Similarly, the second elongate member 14 includes a jaw 22 in the form of a cutting blade at a front end portion 23 thereof, a handle 24 at a rear end portion 25, and an intermediate middle portion 26 of the jaw 22 and handle 24. Referring more particularly to Figure 2, the mower 10 is preferably provided with a compression spring (not shown) between the elongated members 12 and 14 to elastically drive the lugs 18 and 24 to a position open, and a mechanism that secures (not shown) to secure the LO mower in a closed position (figure 1). In the alternative, other driving mechanisms such as a leaf spring secured to one of the handles and that has a free end that engages the other handle can be used .. As for the prior art carriers, the user holds the mower 10 such that the thumb is placed in the front region of the handle 24, and the four i-shelf fingers are placed on the handle 18 which is pivotally mounted around the pivot pin 30 which defines a rotation axis 41. The pin 30 is received in a hole 31 formed in the portion half 20 of the elongated member 12, and in a second hole 33 formed in a side projection 38 located in the front region of the handle 18. As shown more particularly in Figure 5, the handle 1 (1 includes a fastener plane). 40 that a portion of the user's four fingers will essentially contact when the user holds the pivotable handle L8.Fn the open position, the fastening plane 40 forms an included angle a with the axis of rotation 1. The angle * is on the scale from 10 ° to 30 °, preferably approximately between 20. Therefore, the clamping plane 40 and the axis of rotation 41 converge at a point away from the edged portions 20 and 26. The simple way of creating an included angle enter the sujet plane 40 and the rotation 41 is to provide the end of the pivotable handle 18 where the pin-30 is received with the side projection 38. As a result, the rotatable handle 18 operates as a lever. Referring now to Figures 7-9, the mower 10 comprises a transmission mechanism 32 which includes a sector of pinion 34 connected to the first gripper 18 and which meshes with a rack 36 connected to the second handle 24. The sector of The sprocket 34 is preferably integrally formed with the first gripper 18 and the zipper 36 preferably is integrally formed with the second gripper 24. The pinion sector 34 and the rack 36 each include a prism of teeth. The rack 36 is curved inward toward the center of the pinion 34, thus allowing the teeth of the rack 36 to continuously engage the teeth of the pinion sector 34 when a force is applied to close the lugs 18 and 24 As will be discussed in more detail below, this hypoid type arrangement of the pinion sector 34 and rack 36 interconverts the rotational force applied by the four fingers of the user to the first handle 18 in a rectilinear force joining the handle 18 and 24. As illustrated more particularly in Figures 2, 7 and 8, the pinion sector 34 is preferably formed in the side projection 38. When the clipper 10 is in the open portion as shown in Figures 2 and 7, the Later-38 projection looks substantially towards handle 24 ,. When the mower 10 is in a closed position (FIG. 1 and 8), the lateral projection 38 substantially looks away from a gripper 24. Now changing to a second embodiment of the present invention, as illustrated in FIG. mower 10 includes a transmission mechanism 32 which has an elongated flexible cable 42 secured to the handle 24. The cable 42 connects the first handle 18 to the second handle 24. A portion of the cable 42 is received in a slot 44 formed on the first handle 18 next to the middle portion 20. When a user applies strength to the second handle 24 with the thumb-and applies a rotational force to the first handle-to 18 with the remaining four fingers, the first handle 18 rotates about the pivot pin 30. While the first handle 18 is rotated, a larger portion of the cable 42 is received in the slot 44, thus attaching the handles 18 and 24. The cable 42 thus interconverts the broken force Applied to the handle L8 in a rectilinear force joining the handles 18 and 24. In the same manner as in the preferred embodiment of the present invention, the handle 18 of Figure 9 is in the form of a crank, which also increases The force applied to the piece being cut. The interaction of the rotational force applied to the handle 18 in a rectilinear force joining the handles can also be achieved by means of frictional engagement instead of gear or cable type constructions. For example, the transmission mechanism 32 may include two opposingly formed surfaces on the handles 18 and 24. The surfaces would have appropriate fiction coefficients of which the rotation of the handle 18 would effectively engage the handle 24 to join the two handles. The benefits achieved by the present invention will now be more conceptually analyzed, whether configured as a rack and pinion arrangement, as a cable joining the two handles, or as frictionally coupling the surfaces. As will be demonstrated below, in both embodiments of this invention, the conversion of a rotational force into a rectilinear force increases the output force of the mower 10, thus increasing the mechanical advantage of the mower 10. Typically, the mechanical advantage The uniqueness of a tool is defined by: HA F ^ al ida • ßpt ruda where Fm? líctak is the total force applied to the workpiece that is to be cut and F.ntraa .. is a total force applied by the user to the mower 10. Mechanical advantage expressions are design tools powerful because they allow the network i optimal design of a tool for improved mechanical advantage. Practical considerations, however, such as the maximum size of the tool will usually limit the degree of acceptable changes to original design. The transmission mechanism 32 of the present invention maximizes the mechanical advantage of the tool 10 while maintaining the tool's prcticability. Referring to Figures 10-12, a user applies the force FN to the first handle 18 and Fn to the second grip 24 which are then converted into an output force in the form of the work performed to cut a piece. of work with jaws 16 and 22. Figure 10 illustrates the present invention wherein the F? er-za FN applied to the first handle 18 is inter-converted into a F? er-za F 'N representing the useful component of the force FN- The rotation of the first handle 18 and coupling of the pinion sector 34 with the rack 36 results in the majority of the force FN being used to join the handles 18 and 24. By contrast, in carriers of prior art , as illustrated in Figures 11 and 12, there is no interconversion of the rotation force of the user's fingers. Therefore, in prior art trimmers, F'N is equal to zero. More particularly, Figure 11 illustrates the Felco 12 trimmer where the handle 18 is rotatable. The only useful purpose of the rotary gripper 18 of the Felco-12 pruner is to dissipate the kinetic friction typically caused by the rotation of the user's fingers while the runner does so. While the rotation of the handle 18 increases the comfort of the user it also increases the instability of the mower in the user's hand, and more likely reduces the mechanical advantage. Figure 12 illustrates a conventional pair of pruning shears that includes a first non-rotating handle 48 and a second non-rotating handle 50. While a user applies FN force to the first handle 48, all four fingers slide and no longer apply a substantial force perpendicular perpendicular FN to the first handle 48. A component of the outside FN also d? s? p > a in kinetic friction forces in the first handle 48. To understand the interconversion of the rotation force in a rectilinear force in the present invention, it is useful to analyze the work done by the mower 10. With reference to figures 13-15 , ß designates the included angle formed by the first handle 18 with the second handle 24. The thumb of the user applies the force Fs to the second handle 24 at a distance d ^ from the pivotable joint 28; the four remaining fingers apply the forces Ft, F¡_ », F3 and F to the first handle 18 at distances d, d2, d3 and d *, respectively, of the pivotable joint 28. The first handle 18 rotates to tr-aes from an angle? (shown in Fig. 14) with radius rj., and due to the circular motion of the first grip 18, the forces F, F2, F3 and F remain substantially perpendicular to the first grip 18. The work associated with the rotation of the first L The handle 18 around the pivot pin 30 is a work function performed in the xy plane and the work performed in the yz plane. The following equation is therefore representative of the total work performed by each user's finger: Wr- (Fn, dr ,, rj., T, ß) - U (> < 5 n (Fr ,, dr ,, ß) + U (y.r> n (Fn, l ",?) where F is a force applied by a finger on the? r-? mer-to-handle 18, dn is the distance between the pivotable joint 28 and the force F ",? is an included angle between the first gripper-to 18 and the second handle 24,? is the angle of the rotation of the first handle 18 and r is a radius of a circle formed by the rotation of the first handle Lí !. The work performed on the xy plane is calculated at the force by the distance traveled by the first handle L8. Yes The circle cunference is 2rfdn, < -arco representing the distance traveled by the first grab bar 18 through the included angle ß is defined by: W, (xv) = F 2pdn- & - = Qd p Sunily, the work done in the yz plane is defined by-: Wt (yz) = F "2pr ^ 60 a ^ lßO Therefore, the work associated with each finger 1-4 in the xy plane and in the yz plane is defined by-: In conventional mowers as illustrated in FIG. 12, the UVJ component does not exist. (UV? = 0) due to which there is no rotation of the handle 48 in the pl not yz. Additionally, as discussed above, the sliding of the four fingers around the handle 40 only results in kinetic friction, i.e., a "workable" loss of work. "Limi Lannente, the rotatable gripper of the pruner-a Felco L2 illustrated in Figure 11 only dissipates the kinetic friction and does not provide a useful force component for joining the lugs 18 and 24. The present invention, however, capitalizes in the rotation of the handle 18 to the terconvert Fn in a rectilinear force by means of the transmission mechanism 32. Referring once more to figures 13-15, the pruning shear 10 increases the output force (FßaJ1 < ia), thus increasing the mechanical advantage of the tool, the i nterconvert i the force L 6 Fn in an internal force F '". The force F '"is a straight line of force Fr, and is not lost in the first grip 18. The rectilinear force F'" is defined as follows: Because of what? FN ra - F'N r'a Therefore F'N = F., rv, r'a where ri »is the distance between the center of the first beam 18 and the axis of rotation 41, r'a is the distance between the axis of rotation 41 and the region where the pinion 14 is shown with the Zipper 36 and Fn is The f? er-za applied by the user. The inventor has pointed out that the transmission mechanism 32 increases the work performed by the mower 10 (ie, as represented by the force multiplied by the distance traveled) by apr-ox by 30% to 40% on the pruner -as of prior art. The mower illustrated in Figures 1 to 15 operates in the following manner. For example, when a branch is to be cut, the user holds the handles 10 and 24 of the open opener 30 as shown in FIG. 2 in such a way that the thumb is placed in the upper part of the body. of the handle 24 and the fingers of the remaining four fingers hold the first handle 18 in the fastening plane 40. The position of the fingers is further illustrated in figure 7. When the handles 18 and 24 are joined together, to cut the branch, the grip 18 rotates around the pivot pin 30 causing the pinion sector 34 to engage the rack 36. As described above, the rotational force exerted on the grip Addition 18 through the four fingers (Fn) is inter-converted into the internal rectilinear force (F ') through the use of the transmission mechanism 32. The cutting force of the mower 10 is further improved by the fastening plane. 40 when forming the included angle a with rotation ee 41 when the mower 10 is in u in open position (figure 2), thus allowing each of the four fingers to cross an approximately equal distance during the cutting movement. Fn the known hand tools of this type where the handles are placed at an angle to each other, the stronger fingers are used only partially, while moving at a distance that is less than that traveled by the weak fingers . Artically, since the handles 18 and 24 are interconnected by means of the transmission mechanism 32, the typical vibration motion of the prior art pruning that occurs at the end of the cut is also damped on the mower 10. in that the above description is an example and preferred embodiments of the present invention, and that the invention is not limited to the specific forms described. For example, the tools according to the invention may also comprise a pair of scissors. Also, the rotation of the handle 18 can be provided by other means than the pin 30. Artically, the transmission mechanism 32 can be constructed in other ways, not necessarily integrally formed with the handles. Also, the convergence of a rotational force in a rectilinear path can be performed by means other than those described herein. These and other substitutions, modifications, changes and omissions may be made in the manner and arrangement of the element described herein without departing from the scope of the appended claims.

Claims (16)

NOVELTY OF THE INVENTION CLAIMS

1. - A manual pivot tool comprising: a pair of opposed first and second elongated members, each member having a jaw at a front end portion thereof, a handle at a rear portion thereof, and a middle portion thereof, first elongated member being rotatable near a rotating ee; a pivot that joins the portions in the middle of the elongated members for the movement in the form of scissors of the lugs and the jaws near the pivot; and a transmission means for interconverting a rotation force applied to the first handle to a rectiimeal force joining the handles.

2. A manual tool according to claim 1, further characterized in that it rotates in the direction of deactivation near the axis of translation.

3. A manual tool according to claim 1, further characterized in that the first handle is rotatable near a pivot pin received in a hole in the middle portion of the first flanged member.

4. A manual tool according to claim 1, further characterized by the transmission means including a sector of pinion connected to the first handle and which meshes with a rack connected to the second gripper.

5. - A manual tool according to claim 4, further characterized in that the pinion sector is integrally formed with the first handle.

6. A manual tool according to claim 4, further characterized in that the rack is integrally formed with the second handle.

7. A manual tool according to claim 4, further characterized in that the rack is curved inwardly for continuous coupling with the pinion sector.

8. A manual tool according to claim 1, further characterized in that the translational means comprises an elongated flexible cable that joins the first handle to the second handle and a groove formed in the first handle close to its middle portion. , a portion of the cable being received in the slot while the first handle is rotated, thus joining the grips,.

9. A manual tool according to claim 1, further characterized by the transmission means comprising a pair of first and second surfaces that are opposite, the first surface being connected to the second handle, the first and second surfaces entering the coupling fpcci? nal at the moment of rotation of the first grip thus uniting the handles.

10. A manual tool according to claim 1, further characterized in that the rotatable handle comprises a fastening plane tangential to a portion of the user's leds when the user holds the rotatable handle.

11. A manual tool according to claim 10, further characterized in that when the jaws are open, the axis of rotation and the fastener plane are joined at a point away from the pivot.

12. A manual tool according to claim 11, further characterized in that the axis of rotation and the clamping plane form an angle included when the jaws are open.

13. A manual tool according to claim L2, further characterized in that the included angle is in the scale of 10 ° to 30 °.

14. A manual tool according to claim 1, further characterized in that the transmission means limits the relative movement of the handles at the end of a cutting motion.

15. A manual tool according to claim 5, further characterized in that the rack and pinion sector linutes the relative movement of the handles at the end of the cutting motion.

16. A manual tool according to claim 1, further characterized in that the pivotable grip is formed as a lever »L7.- A manual tool in accordance with claim 1, also characterized because the tool is a pair of 11-pieces. 10. A manual tool according to claim 1, further characterized in that the tool is a pair of pruning shears. 19. A manual pivot tool comprising: a pair of opposed first and second elongated members, each member having a jaw at a front end portion thereof, a handle at a rear portion thereof, and a middle portion where members cross over each; a pivot that joins the portions in the middle of the opposed elongated members for the movement in the form of scissors of the handles and the jaws near the pivot; and wherein the handle of the first elongated member has a center point and is rotatable about an axis of rotation outside the center point, the handle of the first member being moved to a region of the second handle of the first member. so that a force of rotation applied to the first handle produces a rectilinear force] joining the handles. 20.- A manual tool according to claim 19, further characterized in that linear recti force is defined by: where r > is the distance between the central point and the e e of rotation, r ', is the distance between the axis of rotation and the region, and FN is the force applied by the user. 21. A manual tool according to claim 19, further characterized in that the rotatable handle produces a usable work for cutting a piece of 5 work received inside the jaws, the work being characterized by: 180 10 where Fn is a force applied by a finger n of the user to the rotatable grip, dr, is the distance between the pivot and the finger n, ß is an included angle between the rotatable grip and the second grip, T is the angle of rotation of the rotatable grip near the axis of rotation, and r is a radius 15 of a circle formed by the rotation of the handle gi abie. 22. A manual pivot tool comprising: a pair of first and second elongated members each being provided with a jaw in a front extr-emo, a grip on a rear end, and a middle portion where 0 members in < ersectan; a pivot that connects the portions in the middle of the members to each to allow movement in the form of scissors of the jaws and lugs around the pivot, where the grip of the first elongated member against the which the fingertips of the user's fingers intend > • positioned, is rotatable about a pivot pin in the first elongated member; and a transmission mechanism provided in the rotatable grip and the second elongated member to convert the rotational force of the handle rotatable into a force that joins the handles. 23. A manual tool according to claim 22, further characterized in that the transmission mechanism comprises a pinion sector mounted on the pivotable handle, and a rack mounted on the second elongated member, the rack that engages the pinion sector. n. 24.- A manual conforming tool with claim 22, further characterized in that the transmission mechanism comprises an elongate flexible element and a groove formed in the first grip close to its middle portion, a portion of the element being received. in the groove while turning the first handle, thus joining the handles. 25. A manual tool according to claim 24, further characterized in that the flexible element is a cable. 26. A manual tool in accordance with Claim 22, further characterized in that the rotatable gripper comprises a fastening plane tangential to a portion of the fingers of a user when the user holds the pivotable handle. 27.- A manual injury «Conformity with the vindication 26, also characterized because when the jaws are open5, the axis of rotation and / or the fastening plane converge at a point away from the portions? in the middle.