Bolt Cutter
20170297211 · 2017-10-19
Inventors
Cpc classification
B26B13/16
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
The invention relates to a bolt cutter (1) which can be used for cutting a workpiece, especially a workpiece that is bolt-like. The bolt cutter comprises a fixed hand lever (3) and a movable hand lever (2). A cutting jaw (8) is fixedly connected to the fixed hand lever (3). The movable hand lever (2) via a ratchet gear (7) is coupled to a movable cutting jaw (6).
In an opening position of the cutting jaws (6, 8) the movable cutting jaw (6) lies against a rest (55) supported by a support spring (54). By manual application of an opening force, the movable cutting jaw (6) can be moved into an enlarged opening position from the mentioned opening position by pressurizing the support spring (54). When the manually applied opening force is removed, the movable cutting jaw (6) automatically returns to the opening position from the enlarged opening position due to the support spring (54).
Claims
1. Bolt cutter for cutting a workpiece as a bolt comprising a) a fixed hand lever and a movable hand lever, b) a fixed cutting jaw, which is fixedly connected to the fixed hand lever, and c) a movable cutting jaw which ca) is supported pivotably relative to the fixed cutting jaw by a pivot bearing and cb) is operatively connected via a ratchet gear to the movable hand lever, the ratchet gear being designed and configured for being automatically transferred into a released state at the end of a cutting stroke, d) an opening spring connected to the movable cutting jaw and designed and configured for moving the movable cutting jaw into an opening position in the released state of the ratchet gear, e) a stop supported by a support spring and defining the opening position of the movable cutting jaw by the establishing of a contact between the stop and the movable cutting jaw, where ea) by manual application of a manual opening force upon the movable cutting jaw the movable cutting jaw is movable from the opening position into an enlarged opening position under an increasing bias of the support spring and eb) due to the support spring the movable cutting jaw is automatically returned from the enlarged opening position to the opening position when the manual opening force is reduced or removed.
2. Bolt cutter according to claim 1, wherein the movable cutting jaw is operatively connected via the ratchet gear and a toggle lever drive to the movable hand lever.
3. Bolt cutter according to claim 1, wherein a) cutting knives formed by the cutting jaws or mounted to the cutting jaws form a receptacle for the workpiece b) in the enlarged opening position the receptacle comprises an insertion opening for inserting the workpiece into the receptacle in an inserting direction and c) the movable cutting jaw has an actuation surface which is arranged in front of the receptacle when seen in the inserting direction so that for an insertion of a workpiece into the receptacle the manual opening force can be applied by the workpiece to the actuation surface of the movable cutting jaw.
4. Bolt cutter according to claim 1, wherein a) the movable cutting jaw comprises a second actuation surface designed and configured for applying the manual opening force and b) in the opening position the second actuation surface protrudes laterally from a head of the bolt cutter.
5. Bolt cutter according to claim 4, wherein a) the movable cutting jaw comprises a ratchet toothing being a part of the ratchet gear, b) an actuation element is formed or arranged in an outer end portion of the ratchet toothing of the movable cutting jaw and c) the second actuation surface is formed by the actuation element.
6. Bolt cutter according to claim 1, wherein a) cutting knives formed by the cutting jaws or mounted to the cutting jaws form a receptacle for the workpiece b) in the enlarged opening position the receptacle comprises an insertion opening for inserting the workpiece into the receptacle in an inserting direction and c) at least one of the cutting jaws comprises a securing element which in the opening position at least partially closes off the inserting opening to the receptacle for the workpiece.
7. Bolt cutter according to claim 1, wherein a) cutting knives formed by the cutting jaws or mounted to the cutting jaws form a receptacle for the workpiece b) in the enlarged opening position the receptacle comprises an insertion opening for inserting the workpiece into the receptacle in an inserting direction and c) the insertion opening comprises a first insertion cross-section in the opening position and comprises a second insertion cross-section in the enlarged opening position, the first insertion cross-section being smaller than the cross-section of the workpiece and the second insertion cross-section being at least as large as the cross-section of the intended workpiece.
8. Bolt cutter according to claim 6, wherein the insertion opening comprises a first insertion cross-section in the opening position and a second insertion cross-section in the enlarged opening position, the first insertion cross-section being smaller than the cross-section of the workpiece and the second insertion cross-section being at least as large as the cross-section of the intended workpiece.
9. Bolt cutter according to claim 1, wherein a) the opening spring exerts an opening moment upon the movable cutting jaw and b) the opening moment decreases as a pivoting angle of the movable cutting jaw changes towards the opening position or the enlarged opening position.
10. Bolt cutter according to claim 9, wherein a) the opening spring biases the movable cutting jaw with a lever arm in opening direction and b) the lever arm decreases with a change of the pivoting angle of the movable cutting jaw towards the opening position or the enlarged opening position.
11. Bolt cutter according to claim 1, wherein a) a head of the bolt cutter comprises three plates lying one above the other, b) an outer first plate forms the fixed cutting jaw, c) an outer second plate forms a covering plate and d) a third plate arranged between the first and second plates forms the movable cutting jaw.
12. Bolt cutter according to claim 11, wherein a spring base of the support spring is supported by the covering plate, the covering plate forms a cover for the ratchet gear and the covering plate is only fixed to the fixed cutting jaw at a position or positions below the movable cutting jaw.
13. Bolt cutter according to claim 2, wherein a) the movable hand lever is supported pivotably relative to the fixed hand lever by a second pivot bearing, b) the movable hand lever comprises a hand lever part extending away from the second pivot bearing, c) a pushing rod is linked by a third pivot bearing to an end portion of the hand lever part turned away from the second pivot bearing, d) in the end portion turned away from the third pivot bearing the pushing rod comprises a second ratchet toothing, which engages with a ratchet toothing of the movable cutting jaw, e) the hand lever part forms a first toggle lever, the pushing rod forms a second toggle lever, the third pivot bearing forms a toggle lever joint between the hand lever part and the pushing rod and the hand lever part, the pushing rod and the toggle lever joint together form the toggle lever drive.
14. Bolt cutter according to claim 1, wherein a) a spring-loaded pawl cooperates with a ratchet toothing of the movable cutting jaw, b) during a cutting stroke the spring-loaded pawl blocks an opening motion of the cutting jaws by engaging with the ratchet toothing of the movable cutting jaw and c) after passing completely through the cutting stroke or after a manual unlocking of the pawl the spring-loaded pawl causes no blocking effect to the ratchet toothing of the movable cutting jaw so that an opening of the movable cutting jaw by the opening spring into the opening position or a manual opening of the movable cutting jaw into the enlarged opening position is possible.
15. Bolt cutter according to claim 13, wherein a) a spring-loaded pawl cooperates with the ratchet toothing of the movable cutting jaw, b) during a cutting stroke the spring-loaded pawl blocks an opening motion of the cutting jaws by engaging with the ratchet toothing of the movable cutting jaw and c) after passing completely through the cutting stroke or after a manual unlocking of the pawl the spring-loaded pawl causes no blocking effect to the ratchet toothing of the movable cutting jaw so that an opening of the movable cutting jaw by the opening spring into the opening position or a manual opening of the movable cutting jaw into the enlarged opening position is possible.
16. Bolt cutter according to claim 1, wherein a cutting knife is detachably fixed to one of the cutting jaws.
17. Bolt cutter according to claim 16, wherein a) the cutting jaw comprises a second receptacle, b) the cutting knife is inserted into the second receptacle and c) the cutting knife is fitted accurately in the second receptacle.
18. Bolt cutter according to claim 16, wherein a third receptacle for accommodating a replacement cutting knife is provided.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.
[0040]
[0041]
[0042]
[0043]
[0044]
[0045]
DETAILED DESCRIPTION
[0046] Referring now in greater detail to the drawings,
[0047] As can be seen best in
[0048] The movable hand lever 2 is supported pivotably by the base body 10 via a (second) pivot bearing 15, which is here is a transverse bolt 16. The movable hand lever 2 comprises a hand lever part 17 extending from the pivot bearing 15 in a direction away from a grip region of the movable hand lever 2. In the end portion of the hand lever part 17 from which the pivot bearing 15 is turned away, in a (third) pivot bearing 19 a pushing rod 18 is linked to the movable hand lever part 2. In the end region turned away from the pivot bearing 19 (which may also be only one ratchet tooth or an engagement element) the pushing rod 18 comprises a (second) ratchet toothing 20. This ratchet toothing 20 of the pushing rod 18 can be brought into engagement with a (first) corresponding ratchet toothing 21 of the movable cutting jaw 6.
[0049] The hand lever part 17 forms a first toggle lever 22. The pushing rod 18 forms a second toggle lever 23. The pivot bearing 19 forms a toggle lever joint 24. Therefore, the hand lever part 17, the pushing rod 18 and the pivot bearing 19 form a toggle lever drive 25.
[0050] Furthermore, via a pivot support 26 (which here is a pivot bolt 27) a pawl 28 is pivotably supported at the base body 10. The pawl 28 has a ratchet toothing 29 (which may also be just one ratchet tooth or an engagement element). With a spring 30 (here a leg spring) the pawl 28 is biased towards the ratchet toothing 21, in which way the ratchet toothing 29 of the pawl 28 engages with the ratchet toothing 21 of the movable cutting jaw 6. The ratchet toothing 21, the pawl 28 and the pushing rod 18 form the ratchet gear 7, which for the embodiment shown is achieved with the integration of the toggle lever drive 25 for driving the pushing rod 18.
[0051] By a spring also the pushing rod 18 is biased towards the ratchet toothing 21, so that during the normal closing stroke of the hand levers 2, 3 the ratchet toothings 20, 21 engage with each other. This engagement for the closing movement couples the movement of the pushing rod 18 to the movement of the cutting jaw 6 for closing the same, while for an opening movement of the hand levers 2, 3, in the way of a ratchet the pushing rod 18 can glide with its ratchet toothing 20 along the ratchet toothing 21.
[0052] It is possible that the pushing rod 18 comprises an protrusion 31, which has no function for the normal movement between the opening position and the closing position of the hand levers 2, 3. If, however, the hand levers 2, 3 are manually brought into an enlarged opening position, with a stop surface 32 the protrusion 31 contacts a stop 33 held by the base body 10, here a transverse bolt 34. Due to the support of the pushing rod 18 by the stop surface 32 on the stop 33 the further opening of the hand levers 2, 3 into the enlarged opening position leads to a pivoting of the pushing rod 18 away from the ratchet toothing 21, in which way the ratchet toothings 20, 21 disengage with each other. The pawl 28 prevents an opening movement of the cutting jaw 6 during the cutting stroke, especially during the ratchet-like movement of the pushing rod 18 relative to the cutting jaw 6, while for the closing movement of the cutting jaw 6 caused by the movement of the pushing rod 18 the ratchet toothing 29 in a ratchet-like way glides along the ratchet toothing 21.
[0053] The pawl 28 has a protrusion 35, which forms a stop surface 36. In the opening position of the hand levers 2, 3, a nose 72 of the hand lever 2 contacts a front side of the protrusion 35 located radial outside with respect to the pivot bearing 26. In this way in the opening position a limitation of the opening movement is achieved. If in this opening position of the hand levers 2, 3, however, the pawl 28 is unlocked in that the pawl 28 is moved away from the ratchet toothing 21 by a finger of the user, the nose 72 is able to pass the front side of the projection 35. Then, a movement of the hand lever 2 into an enlarged opening position is possible. In the enlarged opening position the nose 72 reaches behind the protrusion 35 and contacts the stop surface 36. In this way, in the enlarged opening position of the hand levers 2, 3 the pawl 28 is fixed in a position pivoted away from the ratchet toothing 21. With guiding the hand lever 2 back from the enlarged opening position into the opening position, the nose 72 glides along the stop surface 36. When the nose 72 has completely passed the stop surface 36, in the opening position the pawl 28 is moved again towards the ratchet toothing 21 which is due to the spring 30.
[0054] With respect to [0055] the automatic release of the pushing rod 18 from the ratchet toothing 21 due to the movement of the hand lever 2, [0056] the limiting of the opening movement of the hand lever with the protrusion 35 of the pawl 28, [0057] the manual unlocking of the pawl 28 and fixing of the pawl 28 in the unlocked state by the hand lever 2 in the enlarged opening position and [0058] the automatic restoration of the locking effect of the pawl 28 with the movement of the hand lever 2 from the enlarged opening position of the hand lever into the opening position of the hand lever 2 and/or [0059] the arrangement and design of the construction elements concerned,
[0060] reference is made to the (not pre-published) European patent application EP 15 191 264.9, which in this respect is incorporated by reference into the disclosure of the present patent application.
[0061] By a (first) pivot bearing 37, here a pivot bolt 38, the cutting jaw 6 is movably supported at the cutting jaw 8. In the end portion turned towards the hand levers 2, 3, the cutting jaw 6 forms a ratchet toothing 21, which extends concentrically to the pivot bearing 37. The ratchet toothing 21 extends approximately over a peripheral angle of 60° to 90°. On the side opposed to the ratchet toothing 21 with respect to the pivot bearing 37, the cutting jaw 6 forms a receptacle 39 for a cutting knife 40. In the corresponding receptacle 41, a cutting knife 42 of the cutting jaw 8 is arranged. Via fixing screws 43, 44, which are screwed into the corresponding cutting jaws 6, 8, the cutting knives 40, 42 are secured and fixed in the (second) receptacles 39, 41. The cutting knifes 40, 42 have straight cutting edges. The cutting edges of the cutting knives 40, 42 are arranged in recesses or undercuts of the cutting jaws 6, 8, so that the cutting jaws 6, 8 protrude from the cutting edges of the cutting knives 40, 42 in a position radially outwards with respect to the pivot bearing 37 and with an extension towards the opposite cutting jaw 8, 6. In this way in each case (here: integrally) a securing element 45, 46 is formed by the cutting edges 6, 8.
[0062] In the end region arranged outwards from the cutting knife 40 with respect to the pivot bearing 37, the cutting jaw 6 forms a (first) actuation surface 47. The actuation surface 47 is oriented radially inwards with respect to the pivot bearing 37 and has an insertion curvature in the region of a projection 48.
[0063] The movable cutting jaw 6 has an actuation element, especially a protrusion or hook 49, which forms a (second) actuation surface 50 and is arranged in the region of the ratchet toothing 21 (on the end-side with respect to the pivot bearing 37 in a circumferential direction).
[0064] Via an opening spring 51, especially a tension spring 71, the cutting jaw 6 is biased in the opening direction. One spring base of the opening spring 51 is linked to the cutting jaw 6, while the other spring base of the opening spring 51 is linked to the base body 10, here to a transverse bolt 52 supported at least by the cutting jaw 8.
[0065] The cover plate 9 on its own or together with the cutting jaw 8 forms a spring chamber 53, in which a spring base of a support spring 54 is supported and possibly the support spring 54 is also partially guided. The other spring base of the support spring 54 directly forms a stop 55. During the movement of the cutting jaws 6, 8, the stop 55 formed by the support spring 54 contacts the cutting jaw 6, here a protrusion 56 of the same, while with more and more movement in the opening direction, the pre-tension of the support spring 55 increases. On the contrary, in the opening position of the cutting jaws 6, 8, the stop 55 contacts a stop of the base body 10, especially the cutting jaw 8 or the spring chamber 53, while a pre-tension remains, in which way the maximum length of the support spring 54 is limited. Accordingly, a closing movement of the cutting jaws 6, 8 from the opening position of the same into the closing position leads to the result that the protrusion 56 of the cutting jaw 6 moves away from the stop 55 while forming an increased clearance 69.
[0066] It can be seen in
[0067] A fixing lever 61 is pivotably supported by the hand lever 2 in a position neighboring the handle. With the manual actuation of the fixing lever 61 the hand levers 2, 3 can be arrested in the closing position. For example, the fixing lever 61 has an protrusion or transverse bolt which in the closing position of the hand levers 2, 3 enters into a recess of the base body 10 in such a way that the opening movement of the hand levers 2, 3 is form-lockingly blocked and is only possible when the fixing lever 61 is manually actuated (possibly against the bias of a spring).
[0068] An opening spring 62 biases the hand levers 2, 3 in the opening direction in such a way that when the actuation forces exerted on the hand levers 2, 3 are reduced or removed, the hand levers 2, 3 automatically enter into the opening position. In the figures the linkage of the opening spring 62, which here is formed as a leg spring, to the base body 10 on the one hand and to the movable hand lever 2 on the other hand is not shown in detail.
[0069] The functioning of the bolt cutter 1 when it is used is in the following explained according to the sequence of the
[0070] In
[0071] If the opening force manually exerted onto the cutting jaw 6 is removed, due to the effect of the support spring 54 the cutting jaw 6 returns to the opening position of the cutting jaws 6, 8 (
[0072] Before the actual closing movement of the cutting jaws 6, 8 occurs due to the successive closing movements of the hand levers 2, 3, the ratchet gear is to be activated first, which is achieved by bringing the hand lever 2 from the enlarged opening position into the opening position (as explained before and according to patent application EP 15 191 264.9).
[0073] At the end of the cutting stroke of the cutting jaws 6, 8 (and the closing stroke of the hand levers 2, 3) according to
[0074] For the embodiment shown, the opening spring 51 is formed by a tension spring 70. The biasing of the tension spring 70 increases as the cutting jaws 6, 8 are closed farther. The tension spring 71 biases the cutting jaw 6 with a lever arm 71 with respect to the pivot bearing 37. This lever arm 71 increases as the cutting jaws 6, 8 are further closed. Therefore, in the opening position of the cutting jaws 6, 8 an opening force exerted by the tension spring 70 onto the cutting jaw 6 results, which is comparatively small and therefore can be supported against a support spring 54, which may have a comparatively small stiffness and/or be supported with small pre-tension in the opening position.
[0075] The overlap 11 in the region of which the cutting jaw 8, the hand lever 3 and the cover plate 9 are fixed against each other, here only extends on the side of the cutting jaw 6 and the ratchet toothing 21 turned towards the hand levers 2, 3. The cover plate 9 preferably ends at the level of the pivot bearing 37 or below the same, so that for the whole movement region of the movable cutting jaw 6 it does not cover the cutting knives 40, 42, the receptacles 39, 41 for the cutting knives 40, 42, the receptacle 63 and the securing elements 45, 46.
[0076] Preferably, the bolt cutter 1 according to the invention is manufactured with a modular production, where by using different partial modules different bolt cutters 1 or other types of pliers can be produced. To mention only a non-limiting example, by using the same hand levers 2, 3 and the same construction elements of the ratchet gear, a combination with crescent-shaped cutting knives is possible for which a further crescent-shaped movable cutting jaw forms the ratchet toothing 21. With respect to further details of such a modular embodiment of the bolt cutter 1 and other pliers reference is made to the (not pre-published) European patent application EP 15 191 261.5-1701, which with respect to the modular design is incorporated by reference into the present patent application.
[0077] It is optionally possible that in the enlarged opening position a latching or locking is possible via a latching device or locking device not shown here.
[0078] Many variations and modifications may be made to the preferred embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention, as defined by the following claims.