Abstract
A device for holding a cutting blade having a cam, including a blade pivot pin for mounting the cutting blade in a pivoting manner on a cutting tool, and a cam pivot pin connected to a driving mechanism of the blade, a first pivot pin chosen from the blade pivot pin and the cam pivot pin being provided with a matching-shape axial lock. The other pivot pin is provided with a manually tightened axial lock. The device includes a catch having a first end with a latch able to be engaged with and held on the first pivot pin by matching shapes, and a second end able to be engaged with and held on the pivot pin provided with the manually tightened axial lock.
Claims
1. Holding device for a cutting blade with a cam, including a blade pivot for the pivoting assembly of the cutting blade on a cutting tool, and a cam pivot connected to a drive mechanism of the blade, a first pivot chosen between the blade pivot and the cam pivot being provided with an axial lock of complementary shape, characterized in that: the other pivot is provided with an axial lock with manual clamping, the device includes a latch presenting a first end with a sliding bolt capable of being engaged and maintained on the first pivot by complementary shape, and a second end capable of being engaged and maintained on the pivot provided with an axial lock with manual clamping.
2. Device according to claim 1, in which the axial lock with manual clamping includes a clamping nut and a blocking device for the clamping nut.
3. Device according to claim 2 in which the blocking device of the clamping nut is integral with the latch.
4. Device according to claim 2, in which the nut blocking device presents a mechanism for temporary release with a flexible blade for the removal of the clamping nut.
5. Device according to claim 2, in which the clamping nut is a knurled or notched nut.
6. Device according to claim 5 in which the blocking device includes a flexible blade connected to the latch and provided with at least one spur at one free end, the flexible blade presenting a resting position in which the spur is in contact with a knurling of the clamping nut, and a free position, capable of being occupied under a bending stress where the spur is away from the knurling.
7. Device according to claim 1, in which the first pivot, provided with an axial lock of complementary shape includes a groove made in the vicinity of one end of the pivot, and in which the sliding bolt, fitted to cooperate with the groove is formed by an edge of an opening made in the latch in the vicinity of its first end.
8. Device according to claim 7 in which the opening presents a first portion sufficiently large for the passage of the pivot, and a second portion, in communication with the first portion of the opening, and adjusted on the bottom of the groove of the pivot, the second portion of the opening being configured to engage in the groove of the pivot when the second end of the latch is engaged on the pivot provided with the axial lock for manual clamping.
9. Device according to claim 1, in which the blade pivot is provided with the axial lock for manual clamping and in which the cam pivot is provided with the positive-fit axial lock.
10. Cutting tool, including a pivoting blade mounted on a blade pivot and an operating mechanism of the cutting blade connected to a cam of the cutting blade through the intermediary of a cam pivot, characterized by a blade holding device according to claim 1.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0037] FIG. 1 is a perspective view of a cutting head of an electric pruning shear of a known type.
[0038] FIG. 2 is a perspective view of a cutting head of an electric pruning shear in conformance with the invention.
[0039] FIG. 3 is an exploded view at a larger scale and in perspective of a holding device for the blade in conformance with the invention, fitting out the pruning shear of FIG. 2.
[0040] FIG. 4 is a perspective view f a locking latch of the holding device of the blade.
[0041] FIG. 5 is a perspective view of a portion of the blade holding device of FIG. 3 illustrating the operation of a nut-blocking device.
DETAILED DESCRIPTION OF IMPLEMENTATION OF THE INVENTION
[0042] Identical or similar portions of the various figures are marked with the same reference numbers so that is possible to refer from one figure to the next.
[0043] FIG. 1 presents a cutting head 12 of a pruning shear 10 of a known type. The pruning shear 10 includes a housing 14, integrating an electric motor 20 concealed by the housing 14, a cutting head 12, and a transmission 16. The transmission connects the motor to the cutting head 12. The term “transmission” designates here the assembly of parts transmitting the motion of the motor to the cutting head. The transmission 16 may feature a reducer 18 mounted on the output shaft of an electric motor 20, and a ball screw-nut mechanism 22 driven by the reducer, and rocker bars 38 described below. On FIG. 1 the motor and the reducer are concealed by the housing 14. A cover 15 providing access to the transmission has been removed so as to show the ball screw-nut mechanism 22. The ball screw-nut mechanism 22 consists of a screw and a nut which cooperate mutually through the intermediary of balls circulating in a ball raceway. The raceway is formed by complementary threads of the nut and the screw. The rotational movement of the screw thus results in a translation of the nut along the screw and parallel to the screw axis. The direction of travel of the nut is dependent on the sense of rotation of the screw. The translation movement of the nut is used to drive the cutting head 12. The cutting head 12 includes a pivoting cutting blade 30 and a fixed counter blade 32, also called “anvil”. The cutting blade 30 is mounted on a blade pivot 34 and can thus pivot between an open position and a closed position on the anvil 32. The cutting blade 30 also features a cam 36 of one piece with the blade. The cam is linked to the screw of the ball screw-nut mechanism 22 through the intermediary of the rocker bars 38. The rocker bars 38 are articulated on the cam around a cam pivot 40. More precisely, one rocker bar is provided on each side of the cam.
[0044] The action exerted by the transmission on the cam 36, through the intermediary of the cam pivot 40, allows the cutting blade 30 to pivot around the blade pivot 34. The cam pivot 40 is, in the example of FIG. 1, a clevis pin. The shoulder is placed against the rocker bar turned towards the anvil 32. The shoulder serves as a stop limiting the axial translation in the linkage of the rocker bars 38 with the cam 36. One may note here that the shoulder could just as well be located against the rocker bar opposite from the anvil.
[0045] The second end of the pivot cam 40 features a groove. After installing the cam pivot in the cam and the rocker bars, an elastic ring or “clip” is placed in the groove. The combined effect of the shoulder and the “clip” thus blocks any unintentional refraction of the cam pivot. The elastic ring or clip constitutes, together with the groove of the cam pivot 40, an axial lock with positive fit.
[0046] The blade pivot 34, too, is a clevis pin of the side of the anvil. Its second end is threaded to receive a forcing nut 44, here a locknut. The blade pivot 34 receives also, on the side of the cutting blade 30, a play-adjusting washer 46.
[0047] The play-adjusting washer 46 is more precisely intended to check the tightening play of the blade. In the type of cutting head such as represented in FIG. 1, warping is expected of the cutting zone as shown in FIG. 1 between the blade and the counter-blade forming the “anvil” in order to ensure a cut with a scissors effect to obtain a fine cut. In the open or the closed position of the cutting blade, there is no play between the cutting blade and the anvil at the blade pivot 34. Rotation of the play-adjusting washer is then difficult or even impossible by action of a finger on the periphery of the washer. By contrast, in the half-way position between the open and the closed position, warping of the cutting zone generates some play at the blade pivot 34. This play is perceptible by easy rotation of the play-adjusting washer around the pivot.
[0048] To adjust the tightness it is recommended to position the blade at half-open and to tighten the nut until effort is required to turn the play-adjusting washer around the pivot. Said washer thus serves as a marker and check in the adjustment of play. In this manner, the operator can finely adjust the play in the tightness by playing on the ease of rotation of the washer around the pivot when the nut is tightened. In example 1, the play-adjusting washer presents over a portion of its periphery a knurling intended to ease its manipulation during the adjustment of the tightness play, said knurled portion being oriented so that its manipulation by one finger of the operator's hand is easily performed.
[0049] Disassembly of the pivoting blade 30 of the pruning shear requires the following operations:
[0050] position the blade at mid-opening before turning the pruning shear off and unplugging it.
[0051] using a screwdriver remove an inspection cover on the housing offering access to the cam pivot 40.
[0052] remove the “clip” 42 using a specific tool.
[0053] loosen and unscrew the tightening nut 44 using a specific wrench.
[0054] Manually remove the play-adjusting washer 46 and the two pivots 34, 40 to release the blade 30.
[0055] Besides the fact that these operations require tooling, they also demand precision with respect to the size of certain parts such as the “clip” 42, or even the fastening screws for the inspection cover on the housing. As mentioned before, these constraints make the blade change operation difficult or even impossible, in the open field, for example in a vineyard during a pruning day in winter.
[0056] FIG. 2 shows a pruning shear provided with a blade holding device according to the invention and facilitating the blade change. The pruning shear of FIG. 2 presents a certain number of parts or portions similar or identical to the pruning shear of FIG. 1, and marked with the same reference numbers. For the sake of simplification the description of these portions is not repeated here, knowing that one can refer to FIG. 1.
[0057] On FIG. 2 a cover piece 15 giving access to a portion of the transmission 16 is shown in the removed position. When the cover piece is in place on the housing 10, it is fastened by a fitting mechanism or a hinge and fitting mechanism (not shown). It can also be fastened here by means of flexible pins, by knurled screws or by any other appropriate fastening means capable of being engaged and removed without a tool.
[0058] FIG. 2 shows the presence of a latch 50 which links the cam pivot 40 to the blade pivot 34. The latch 50, or at least a first end 52 of the latch, forms together with the end of the cam pivot 40, a form-fitting axial lock. The latch cooperates in effect with the end of the cam pivot 40 in order to prevent or at least limit an axial movement of the cam pivot relative to the cam 36 and relative to the rocker bars 38.
[0059] The axial movement of the pivot cam is also limited on its opposite end by a shoulder 41 such as described in reference to FIG. 1. In other implementations not shown, for example when a single rocker bar is used, the cam pivot can be press-fitted on the cam or on the rocker bar and not be provided with a shoulder
[0060] Contrary to the “clip” 42 of FIG. 1 which is maintained on the cam pivot by elastic deformation, the latch 50 is primarily maintained through the intermediary of its second end 54. The latter is in fact retained on the blade pivot by damping. The engagement of the latch on the cam pivot is explained in more detail in the description below.
[0061] It can also be seen in FIG. 2 that the tightening nut 44 of FIG. 1 can be replaced by a knurled clamping nut 56 which gets placed on the threaded end of the blade pivot. The main advantage of a knurled nut as compared to the hexagonal nut visible on FIG. 1 is that it does not require a tool for tightening, the knurling allowing an easy manual grip of the nut for exerting an effort of tightening or loosening. Another function of the knurling on the nut is described in reference to the following figures.
[0062] The knurled nut forms h the threaded end of the blade pivot a manually tightened axial lock.
[0063] FIG. 3 shows at a larger scale various components of the blade holding device according to the invention. On FIG. 3 the blade pivot 34 is removed from the cutting blade 30 and the counter-blade 32. This makes it easier to distinguish a shoulder 35 of the blade pivot 34 which comes to rest on the face of the counter-blade 32 opposite of the cutting blade 30. It can also be seen that the free end of the blade pivot presents a threading 59. This threading is adapted to the knurled tightening nut 56. The pivot gets seated in a through-hole 31 of the cutting blade 30 and of the counter-blade 32. Fastening of the cutting head formed by the cutting blade 30 and the counter-blade 32 on the tool body is obtained through the intermediary of a fastening tab 33 of the counter-blade. A flat or relief 37 is made axially on the spindle of the blade pivot 34. It cooperates with a mating profile of the through-hole of the cutting blade 30, and permits making the blade pivot 34 and the cutting blade 30 integral in rotation. This measure promotes the blocking of the knurled tightening nut 56 described elsewhere, the adjustment of the tightness play between the blade and the counter-blade and avoids any loosening of the blade pivot in the knurled clamping nut 56 under the effect of the movement of the cutting blade under repeated cutting efforts.
[0064] FIG. 3 also represents the cam pivot 40 at a larger scale. Particularly visible is a shoulder 41 of the cam pivot which rests on one of the rocker bars 38. As FIG. 3 shows, the end of the pivot forming the shoulder 41 is shaped for gripping the pivot by hand. It constitutes a small gripping appendix of the pivot and contributes to making the blade change operation easy and tool-free, while reducing the risk of losing any of the parts. The cam pivot passes through through-holes of a first rocker bar 38, of the cam 36, then of a second rocker bar 38, from the shoulder 41 on up.
[0065] FIG. 3 shows that the end of the cam pivot 40 also passes through an opening 66 made in the first end 52 of the latch 50, and adapted to the diameter of the pivot. A chamfer 60 at the free end of the cam pivot is made to facilitate its passage through the opening 66.
[0066] FIG. 3 also shows that the cam pivot 40 is provided with a groove 62 in the vicinity of its end. Now, the opening 66 of the latch 50 presents a narrowed portion adjusted to the diameter of the cam pivot 40 at the bottom of the groove. This narrowed portion is delimited by an edge 72 acting as slide bolt which engages in the groove 62 of the cam pivot when the latch 50 is pushed in the direction of the through-hole 31 of the blade pivot 34.
[0067] The second end 54 of the latch also presents an opening 76 dimensioned for the passage of the blade pivot. The latch is so dimensioned that the edge 72 of the opening 66 at the first end 52 of the latch is completely engaged in the groove 62 of the cam pivot when the opening 76 of the second end 54 matches up with the through-hole 31 of the cutting blade 30 and of the counter-blade 32. The latch 50 is maintained in this position as soon as the blade pivot 34 is engaged through the opening 76 of the second end 54.
[0068] The peripheral edge 72 of the opening of the first end 52 of the latch constitutes a sliding bolt which cooperates with the groove 62 of the cam pivot to form an axial lock by positive fit. This lock limits or prevents an axial movement of the cam pivot 40 relative to the rocker bars 38 and relative to the cam 36 of the cutting blade 30.
[0069] It can also be seen on FIG. 3 that the latch 50 does not come into direct contact with the cutting blade 30 but rests on a play-adjusting washer 46. The play-adjusting washer 46 is provided for checking a tightness play in the manner described in reference to FIG. 1.
[0070] FIG. 4 shows at a larger scale the latch 50 used for locking the earn pivot. Visible is the opening 66 made in the vicinity of the first end 52 of the latch for the passage of the cam pivot and the opening 76 made in the vicinity of the second end 54 of the latch for the passage of the blade pivot 34. The opening 76 of the second end of the latch is essentially round. It presents an edge forming a sort of thrust washer opposite the bearing surface of the knurled nut (not shown).
[0071] One can see that the opening 66 of the first end 52 of the latch presents a narrowed portion. As indicated above, it is fitted on the bottom of the groove of the cam pivot (not shown). The edge of the opening in this narrowed portion constitutes the slide bolt of the lock.
[0072] Also noticeable on FIG. 4 is the presence, on the latch 50, of a flexible blade $0 connected to the body of the latch 50 by one of its ends 84. The opposite end of the flexible blade 80 is free. It is provided with a spur 86. The flexible blade 80 or at east its end 84 connected to the body of the latch 50 gives it sufficient elasticity to be bent by pressure exerted by a user's finger. The bending of the blade 89 allows modifying the height of the spur, relative to the edge of the opening 76 of the second end 54 of the latch 50.
[0073] The latch as presented in FIG. 4 is preferably a metallic piece. It may be shaped by stamping. Its length, and more exactly the distance separating the sliding bolt 72 in its first end and the opening 76 in its second end, is fixed based on a distance separating the blade pivot and the cam pivot. This latter distance is also fixed by the corresponding through-holes of the cutting blade.
[0074] The flexible blade 80 and the spur 86 form a blocking and retaining device for the knurled tightening nut 56 as shown in FIG. 5.
[0075] FIG. 5 shows the holding device of a cutting blade of FIG. 5 in a configuration where the blade has been installed. The blade pivot 34 is engaged in the counter-blade 32, the cutting blade 30, and the play-adjusting washer 46. The knurled clamping nut 56 is screwed on the blade pivot. The first end 52 of the latch 50 is engaged on the cam pivot 40 and the second end 54 of the latch is clamped between the knurled clamping nut 56 and the play-adjusting washer 46. It is to be noted here that the thickness of the play-adjusting washer corresponds essentially to the thickness of the rocker bar 38 on the blade side so that the latch 50 is positioned essentially in parallel to the face of the cutting blade. The basis of the latch 50 is in this case part of a plane. Other shapes of the latch are however conceivable, for example, in case the play-adjusting washer is absent or for other configurations of the cutting head. For example the latch may have a shape that is adapted so its end 54 can come into contact directly with the cutting blade. The play-adjusting washer or any similar device may thus be placed between the latch and the clamping nut.
[0076] It can be observed that the length of the flexible blade 80 of the latch 50 is such that the spur 86 reaches the knurled clamping nut 66. The flexible blade 80 is shown in a position of rest in which the spur becomes engaged on a relief 57 of the knurling of the clamping nut 56. The blade and the spur thus inhibit the rotation of the nut and prevent its accidental loosening.
[0077] When the user applies pressure on the flexible blade 80 in the direction of the cutting blade 30 the blade will occupy a position of release in which the spur finds itself disengaged from the knurling relief. The knurled clamping screw 56 presents in effect, over a portion of its height, a peripheral edge 58 without knurling and withdrawn from said knurling. This edge is turned towards the latch 50.
[0078] The flexibility of the flexible blade 80 and the peripheral edge 58 with no knurling constitute a releasing mechanism of the blocking of the knurled clamping nut 56. It is activated to release the nut during its installation, during its removal or during an adjustment of the tightness.
[0079] FIG. 5 also affords a better view of the fastening tab 33 of the counter-blade 32. It presents through-holes for fastening screws. It should be stressed that the fastening screws, not shown, never need to be removed for changing the cutting blade 30.
[0080] Thanks to the device of the invention the assembly and disassembly of the cutting blade are greatly facilitated and can be done entirely by hand. It comprises:
[0081] installation of the first end of the latch on the cam pivot,
[0082] an easy slide of the latch to engage the sliding bolt on the cam pivot to match up the opening of the second end of the latch with the through-hole of the blade pivot, while releasing the blockage device of the knurled clamping nut,
[0083] installation of the blade pivot and the tightening of the knurled clamping nut on this pivot.
[0084] releasing the blocking device of the clamping nut, thus preventing the relative rotation of the clamping nut in relation to the cutting blade, and thus setting the tightness play between the cutting blade and the counter-blade.
