Device for manually tightening a pliers tool

Abstract

The invention relates to a device for assisting the manual operation of a plier tool (1), having two arms (2, 3) articulated about an axis (4) which divides each arm into a jaw (2a, 3a) and a handle (2b, 3b), characterized in that it comprises a cable (11) fixed at one end (10) to a handle (2a) of the pliers and a sheath (13) fixed at one end to the other handle (2b) of the pliers (1), in which the cable (11) is slidably housed, and an actuator (22) for moving the cable (11) within the sheath (13) from its other end (20) at least in the direction of clamping the pliers (1). [Figure 1]

Description

Title of the invention: Device for assisting the manual tightening of a pliers tool

[0001] BACKGROUND OF THE INVENTION

[0002] The use of pliers is extremely common in many industrial sectors. These tools can take various forms depending on their intended use. Examples include crimping pliers, wire strippers, riveting pliers, welding pliers, gripping pliers, scissors, shears and pincers, and pruning shears... The craft and industrial sectors involved are also very diverse, ranging from cable manufacturing to leather goods, including plumbing, metallurgy, construction, and automotive manufacturing...

[0003] In most cases, the use of these tools is manual, because the automation of the operations carried out is impossible even though they are repetitive, due, on the one hand, to the fact that they are carried out most of the time in an environment which varies, since they are mostly portable tools, and on the other hand, that they require a know-how, a dexterity of execution which it is not possible to transcribe into an algorithm.

[0004] The operators concerned are then subject to musculoskeletal disorders in the upper limbs (hands, wrists, elbows, shoulders...) which quickly become disabling and, as a result, have economic and social repercussions both for the operators themselves and for employers and social insurance.

[0005] It is known to equip a gripper with a motor that is inseparable from the gripper jaws. This results in heavy and unwieldy tools. For example, see document CN 210046543U.

[0006] There is therefore a need, poorly or not met, to relieve the efforts that an operator of this type of tool must develop in order to limit the disadvantages mentioned above, while preserving the qualification of this operator, his know-how and his dexterity which he will be able to continue to exercise without significant hindrance.

[0007] SUBJECT OF THE INVENTION

[0008] To this end, the invention relates to a device for assisting the manual operation of a plier tool, having two arms articulated around an axis which divides each arm into a jaw and a handle, characterized in that it comprises a cable fixed to one handle of the pliers and a sheath fixed at one of its ends to the other handle of the pliers in which the cable is housed by sliding and an actuator to move the cable in the sheath from its other end at least in the direction of clamping.

[0009] This architecture allows a gripper to be equipped with a mechanical power source located away from the gripper. The gripper therefore retains its initial maneuverability and, for the operator, in addition to the relief it provides, retains all the possibilities of exercising their skill and know-how as with a standard tool.

[0010] The device is also characterized by the removable fastening means, adapted to most handles of pliers or handles of pruning shears, pincers, loppers, etc., for the cable and sheath respectively attached to each arm of the pliers. The pliers are operated according to the same kinematics as a bicycle brake.

[0011] Thus, in a preferred embodiment, these fastening means comprise, for one arm, a finger carrying at the end a cable attachment bracket and for the other arm a finger provided with a stop or sheath stop opposite the bracket, each finger comprising a rear part forming a splint for its attachment to the clamp arm for which it is intended.

[0012] More precisely, the device comprises, at this level, a collar formed of an open outer clamping ring with a closing means for narrowing its inner diameter and elastically deformable internal means, suitable for closely joining the rear part of the finger and the handle when closing the ring.

[0013] These internal means are such that they transform the narrowing of the outer ring into a pinching of the finger against the handle in the direction of operation of the gripper and a blocking of the finger's rotation around the handle. This immobilization ensures good transmission to the jaws of the gripper of the two arms via the sheath / cable transmission.

[0014] The actuator for the relative movement of the cable and the sheath can be of any shape known, for example, as an electric or pneumatic cylinder. The movement of the rod in such a cylinder is transmitted directly or via a pulley system, which multiplies the rod's stroke, depending on the required travel distance between the cable and the sheath. As an example, in a typical manual clamp with arms approximately 30 cm long, the maximum opening at the end of the handle is about 18 cm.

[0015] A preferred actuator is in the form of a pneumatic "muscle" whose principle is described in document FR 2,076,768. This muscle is commercially available. In a particular architecture of the invention, it is fixed to a support structure, so as to form the variable-length connecting rod of a crank-connecting rod system in which the crank is a cam-shaped disc around which the cable is wound, while the support structure acts as a stop for the other end of the sheath that guides the cable.

[0016] More precisely, the connecting rod is formed by the extended muscle of a drive cable from a first driving cam, which is locked in rotation with a driven cam disc around which the driven cable, guided by the sheath, is wound. Both the driving and driven cams have a spiral profile so as to create a transmission ratio greater than one between the displacement of the driving cable and that of the driven cable within the sheath. This design is advantageous in this particular case for the required stroke lengths (18-20 cm) because it constitutes a compact transmission chain, especially compared to a gear transmission.

[0017] Another feature of the invention lies in the existence of a pneumatic muscle control handle fixed to one of the aforementioned fingers and equipped with at least one button for actuating a control circuit for supplying compressed gas to the muscle. The muscle control circuit can be electrical or pneumatic. In the latter case, the main power source for the muscle will be used as the energy source for the control circuit, thus making the device completely self-contained if, for example, the pneumatic source is a compressed gas cylinder. Brief description of the drawings

[0018] The invention will be better understood from the description and drawings given below. Reference will be made to the figures in which:

[0019] [Fig-1] is a diagram illustrating the device of the invention and its functionality,

[0020] [Fig.2] functionally illustrates the means of adapting the device according to the invention of a manual pliers tool,

[0021] [Fig.3] illustrates, by means of a diagram, the actuator implemented in the invention at rest,

[0022] [Fig.4] illustrates by means of a diagram, the actuator implemented in the invention in operation,

[0023] [Fig.5] illustrates, by means of a diagram, a pneumatic embodiment of the means of actuator control. DETAILED DESCRIPTION OF THE INVENTION

[0024] In [Fig.1], a clamp 1 is shown having two arms 2 and 3 articulated around an axis 4. This axis divides each of the arms into a jaw 2a, 3a, and a handle 2b, 3b.

[0025] The device according to the invention comprises two fingers 5 and 6 each fixed to one of the handles 3b and 2b by a part 5a and 6a which forms a kind of splint, by means of a collar 8 and 7 which makes it possible to firmly secure the finger to the handle of the corresponding clamp, taking into account the different sections which can be found on existing clamps.

[0026] This method of fastening by collar, illustrated in more detail by the diagram in [Fig. 2], is only one example of an embodiment. It can be replaced by any other method of fastening equivalent, such as for example a lacing, embracing the finger and the corresponding handle, equipped with a means of quickly tightening and loosening a link looped several times around the finger and the handle, like the devices implemented in ski boots (inspired for example by US document 5,934,599).

[0027] Finger 6 carries a bracket 9 for attaching the end 10 of a cable 11, while finger 5 carries a stop 12 for the end 13a of a guide sheath 13 for this cable 11. It is understood that sliding the cable within the sheath acts on the end of each arm of the gripper in the direction of its closing or opening (opening generally assisted by an elastic element 14 fitted to the gripper). The direction of the cable between the two arms of the gripper must be substantially perpendicular to the pivot axis for optimal gripper actuation efficiency. Fingers 5 and 6 are therefore oriented accordingly so that the bracket is substantially opposite the stop in the plane of travel of the gripper.

[0028] It will be noted in this [Fig. 1] that one of the fingers, for example finger 5, carries a member 15 which forms both the support for control elements (switches, pushbuttons, etc.) of an actuator for the cable 11 sliding in the sheath 13 and a means for gripping and positioning the clamp. An example of an actuator will be described opposite Figures 3 and 4.

[0029] Figure 2 is a functional diagram of the coupling means for attaching the splint portion, for example 6a, from each finger to the handle, for example 3b, of the gripper. These means comprise a split ring 16 that can be opened and closed by means of a means 17 (for example, a screw / nut), which, when tightened, is capable, on the one hand, of forcing the splint 6a firmly against the handle 3b in a direction perpendicular to the plane of travel of the gripper and, on the other hand, by means of deformable elements 18-19 acting as jaws, of laterally stabilizing this attachment. This coupling is designed to be easily disassembled.

[0030] Figures 3 and 4 schematically represent an actuator in its inactive state ([Fig.3]) and in its active state ([Fig.4]). These figures show the other end 13b of the sheath 13 and the other end 20 of the cable 11. The actuator comprises a support structure 21 for a cylinder 22 (here a pneumatic muscle such as exists on the market, for example, marketed by the company FESTO) whose chamber is articulated (suspended) at 23 to the structure 21 while its other end is attached to the periphery of a cam pulley 24 by a motor cable 22a. The muscle 22 cable 22a assembly constitutes the connecting rod of a connecting rod / crank system, the crank of which is the pulley 24. The latter is mounted for rotation on the structure 21 around an axis 25 and locked in rotation around this axis with a cam pulley 26 (point 27) to which is attached the end 20 of the driven cable 11 to wind around its periphery. The end 13b of the sheath 13 is blocked relative to the structure 21 by a stop 21a of the latter.

[0031] In [Fig. 3], the cylinder 22 is relaxed. The cable 11 is then fully extended on the side of the gripper, which is then in its fully open position, due, for example, to the elastic element 14. The operator, wishing to tighten the gripper, grasps the control element 15 of the actuator 22 (the cylinder) in order to maneuver the gripper to position it in its working area, using the other hand if necessary. The operator then operates the switch(es) / button(s) on this element 15 to control the power supply to the cylinder 22. The inflation of the pneumatic muscle 22 ([Fig. 4]) leads to its shortening, causing the drive pulley 24 to rotate in the direction of arrow A, which in turn causes an identical angular rotation of the driven cam pulley 26 and the winding of the cable 11 around its periphery. The cable is therefore retracted into the sheath at the clamp, which causes the jaws of the latter to close.The winding / unwinding profile of the cams 24-26 is determined to provide the most favorable gear ratio for a minimum of space and the most suitable (clamping) force for the type of clamp to which the device of the invention is adapted. These are spiral profiles.

[0032] In one embodiment of the actuator, it will be placed, along with its support, in a housing, for example a portable one, which also encloses the power source (battery or compressed gas cylinder). This housing may be transparent so that the operator can visually check or observe the operation of the actuator.

[0033] The actuator can be controlled by any electrical or pneumatic means known per se. Figure 5 is a functional diagram of the control of the actuator 22 by means of a pneumatic circuit that incorporates a safety feature.

[0034] In this figure, the actuator 22 and a pneumatic source 27 are housed in a casing 28. The actuator is supplied by the source through a normally closed, monostable pilot valve 29. The pilot pressure of this valve 29, from the source 27, is admitted through a normally closed, monostable on / off valve 30, which is itself housed in the component 15 carried by the finger 6 described above. This is, for example, a push button that the operator can press. The actuator 22 is in constant communication with a leak channel 31 that opens to the atmosphere at the gripping component 15, i.e., near the hand of the operator who presses the on / off button. The presence or absence of this leak, felt by the hand, indicates to the operator whether the actuator is active or not.The leak channel is also equipped, at the gripping member 15, with a normally open exhaust valve 32, the passage cross-section of which can be manually adjusted by the operator using a trigger or a knob. The leak channel 31 is provided upstream of the flow exhaust valve. adjustable, with a unidirectional flow restriction 33 (tap), also adjustable. The same regulator 34 is interposed between the valve 29 and the supply / drain line of the cylinder 22. Finally, a safety valve 35 with adjustable setting limits excessive pressure buildup in the pneumatic circuit.

[0035] The pneumatic connection between the actuator 22 and the handle 15 is achieved by means of flexible hoses, grouped in bundle 36 so as not to impair the maneuverability of the device.

[0036] The pneumatic supply circuit for the cylinder is adjustable and adaptable to the different grippers to which the device of the invention can be associated and to the pressure source to which it can be connected. Thus, with the distributor 29 open via the pilot 30, as well as the limiter 33 and the exhaust valve 32, the output flow rate of the flow limiter 34 is adjusted so that the pressure established in the cylinder 22 causes a slight shortening of the latter, balanced by the forces resisting this shortening, namely the friction between the cable and the sheath and the force of the return mechanisms acting on the gripper in its open state. Then, with the exhaust valve still open, the limiter 33 is actuated in the direction of its flow restriction to obtain additional inflation of the jaw muscle, thus closing the gripper corresponding to an approach stroke with minimal force applied to the workpiece being handled by the gripper.With these settings configured for the entire series of repetitive operations to be performed, the operator only needs to operate trigger 32 to pinch, crimp, cut, etc., depending on the pliers used.

[0037] The invention offers numerous advantages. First, the device's flexibility of use should be mentioned, as the actuator can be positioned away from the work area, allowing the operator to use the gripper as needed. Its lightness, ease of adjustment, compact size, and energy autonomy enable it to be used in any operating condition (in a workshop, outdoors, etc.) and even to be portable in the operator's backpack. The actuator can advantageously be enclosed in a housing that surrounds it along with its support structure. This housing, being transparent, allows the operator to visualize the amount of assistance available by observing the behavior of the flexor muscle.

Claims

Demands

1. .A tool consisting firstly of a gripper (l), having two arms (2, 3) articulated about an axis (4) which divides each arm into a jaw (2a, 3a) and a handle (2b, 3b), and secondly of means for assisting the operation of this gripper (l) consisting of a cable (11) fixed at one of its ends (10) to one of the handles (2a) of the gripper (1), a guide support for the cable fixed at one of its ends (13a) to the other handle (2b) of the gripper (1), and an actuator for moving the cable relative to the support, characterized in that the guide support is a sheath (13) in which the cable (11) is housed, and in that the actuator (22) is an electric, pneumatic, or pneumatic cylinder for moving the cable (11) within the sheath (13) from its other end (20) at least in the direction of gripping. (1) and in that the attachment of the cable (11) and the sheath (13) to the aforementioned handles (2b,3b) is ensured by removable means (7,8).

2. . Clamping tool according to claim 1, characterized in that the means (7, 8) for fixing, removable, of the cable (11) and the sheath (13) respectively to each arm (2, 3) of the clamp, comprise, for one arm, a finger (5) carrying at its end a bracket (9) for attaching the cable and for the other arm a finger (6) provided with a stop (12) or stop of the end (13a) of the sheath (13) opposite the bracket, each finger (5, 6) comprising a rear part (5a, 6a) forming a splint for its attachment to the arm of the clamp for which it is intended.

3. . Clamping tool according to claim 2, characterized in that each fastening means (7, 8) comprises a collar formed of an open outer clamping ring (16) with a closing means (17) for narrowing its inner diameter and elastically deformable internal means (18, 19) adapted to closely join the rear part (5a, 6a) of the finger (5, 6) and the handle (2b, 3b) when closing the ring (16).

4. . Clamping tool according to claim 1 characterized in that the actuator (22) is fixed to a support structure (21) so as to form the variable-length connecting rod of a crank-connecting rod system in which the crank is a cam-shaped disc (26) around which the cable (11) is wound, while the support structure (21) constitutes a stop (21a) for the other end (13b) of the sheath which guides the cable.

5. . Clamping tool according to claim 4, characterized in that the connecting rod is formed by a pneumatic muscle (22), extended by a drive cable (22a) and a first drive cam (24), locked in rotation (27) with the crank cam disc (26).

6. . Tool-clamp according to claim 2, characterized in that a control handle (15) for the actuator (22) is fixed on one of the aforementioned fingers (5) and is equipped with at least one actuation button for a control circuit of this actuator (22).

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