Clamping tool with clamping force sensor

Abstract

The invention relates to a clamping tool with a device for generating a clamping position, in which two clamping elements (3, 4) apply a clamping force to a workpiece, the counterforce of which is taken up by a connection member (1) connecting the clamping elements (3, 4) to one another, with an element that deforms under generation of the clamping force (K), and with a sensor element (5), which converts the deformation of the deformable element into an electrical signal which can be used to determine the value of the clamping force (K). In accordance with the invention the deformable element is formed by a blocking element (2) which acts as a push-back block and above which one of the clamping elements (4) is supported on the connection member (1) in the clamping position.

Description

field of technology

[0001] The invention relates to a clamping tool with a device for generating a clamping position in which two clamping elements apply a clamping force to a workpiece, the counterforce of which is absorbed by a connecting member connecting the clamping elements to each other, with an element that deforms when the clamping force is generated and with a sensor element that converts the deformation of the deformable element into an electrical signal from which the value of the clamping force can be determined.

[0002] The invention also relates to a method for operating the clamping tool in combination with a transmitting / receiving device. State of the art

[0003] DE 20 2008 000 295 U1 describes a C-shaped clamping tool according to the preamble of claim 1, in which the clamping force applied between two clamping elements can be determined by means of a sensor element.

[0004] US Patent 6,758,098 B1 also describes a C-shaped clamping device in which a strain gauge is used to determine a clamping force by the deformation of a deformable element.

[0005] DE 21 2005 000 037 U1 describes a one-hand clamping clamp with a sensor for determining the applied force, wherein the sensor is arranged on a clamping jaw.

[0006] DE 10 2013 101 479 A1 describes a clamping device with a fixed jaw fixed to a rod and a movable jaw supported by a drive housing. Inside the drive housing is a drive element that can be moved towards the fixed jaw by the reciprocating movement of a drive arm relative to the rod, or, in another mounting configuration, away from the fixed jaw. When the drive arm is actuated, the drive element wedges itself against the rod and is returned to its original position by a return spring. A locking element is also attached to the rod. This locking element acts as a backstop, which can be released by actuating a release lever. Summary of the invention

[0007] The invention is based on the objective of further developing a clamping tool of the generic type in a way that is advantageous for use.

[0008] The problem is solved by the invention specified in the claims, wherein the dependent claims represent not only advantageous further developments of the invention specified in the dependent claims but also independent solutions to the problem.

[0009] First and essentially, it is proposed that the deformable element, which deforms when the clamping force is applied, is a locking element by which one of the clamping elements is supported on the connecting member in the clamping position. In a variant of the invention, it is proposed that the locking element is designed and has a function as described in DE 10 2013 101 479 A1. The full disclosure of this document is therefore incorporated into this application, also to include features of this document in the claims.

[0010] It is specifically provided that the locking element can be moved from a locking position supported on the connecting member to a release position. In the release position, the clamping element, which is supported on the connecting member by the locking element (in particular a clamping jaw), can then be moved in the direction of the opposing force against the connecting member, for example, a rod. According to the invention, the clamping element can be arranged on a drive housing that can be moved along the connecting member. In the release position, the drive housing can be moved, in particular, in the direction of extension of the connecting member. The drive housing can have a drive element, in particular in the form of a drive arm, with which the drive housing can be moved stepwise in the direction of the clamping force by a repetitive movement of the drive element. The sensor element can be a strain gauge.The sensor element is arranged, in particular, on a surface of the locking element. It can be glued to it. It can be embedded in a pocket. It can also be attached to the locking element in some other way. The essential point is that any deformation, especially elongation, of the locking element is transmitted to the sensor element so that the deformation can be converted into an electrical signal from which the clamping force can be determined. The element, in particular the locking element, can have a window through which the connecting element, for example a rod, extends. The window can have two parallel legs, each adjacent to edges that are angled against the connecting element in the locked position. The sensor element can be arranged on one of these legs. The sensor element can thus extend alongside the rod.Furthermore, an electronic device can be provided that evaluates the signals supplied by the sensor element. The evaluation can be performed in such a way as to determine a value of the clamping force. It is also preferably provided that the sensor element can communicate with a transmitter / receiver device via a wired or wireless transmission link. The signals supplied by the sensor element or the signals or data processed by the electronic device can be transmitted from the clamping tool to the transmitter / receiver device via the transmission link. In a preferred embodiment of the invention, it is proposed that the transmitter / receiver device be a mobile device, for example, a tablet computer or a smartphone.It is further preferably provided that the clamping tool according to the invention is used together with a mobile device, wherein the mobile device is programmed such that it can display the supplied data or values ​​on a screen, for example, a display. The mobile device is preferably programmed such that an application case can be selected from a group of application cases in the program, with each of the application cases in the group being assigned a maximum and / or minimum clamping force. The program is then able to inform a user whether a minimum clamping force has been reached or whether a maximum clamping force has been exceeded. The invention further relates to a method for using the tool according to the invention with a transmitter / receiver device which is capable of displaying the clamping force values ​​or values ​​derived therefrom.According to a further development of the invention, the clamping tools of a plurality of clamping tools each have an electronic device that evaluates signals supplied by the sensor element. The electronic device is capable of emitting a sensorily detectable signal, in particular an optical or acoustic signal, when the actual clamping force deviates from the target value, lies outside a target value range, is below a threshold value, or is above a threshold value. It is particularly provided that each of the plurality of clamping tools used together emits a different signal, in particular a different acoustic signal, so that the type of signal allows identification of which clamping tool is experiencing a clamping force deviation. Brief description of the drawings

[0011] An embodiment of the invention is explained below with reference to the accompanying drawings. These show: Fig. 1 is a top view of a clamping tool as known from DE 10 2013 101 479 A1, Fig. 2 enlarges the one in Figure 1 Section marked II with the housing cover removed in a basic position, Fig. 3 a representation according to Figure 2 However, in a released position, Fig. 4, which is in the Figures 2 and 3 The blocking element shown is in a top view, and Fig. 5 shows the blocking element in a perspective view. Description of the embodiments

[0012] The device shown in the drawings is a clamping device as described in DE 10 2013 101 479 A1 with regard to its mechanical construction and mechanical function, which is why the details of DE 10 2013 101 479 A1 are included in the disclosure content of this technical teaching.

[0013] A first clamping element 3 forms a fixed clamping jaw, which is attached by means of an arm to a free end of a connecting member 1, which is a rod. The rod can have a flat, oval, or round cross-section and can be made of steel. The arm supporting the clamping jaw 3 can also be attached to the other free end of the rod (connecting member 1). In this case, the clamping tool functions not as a clamping clamp but as a spreading clamp.

[0014] A second clamping element 4, which forms a clamping jaw, is attached to a drive housing 6. The drive housing is slidably mounted on the connecting link 1. It can always be moved in the direction of arrow K. However, it can only be moved in the direction of arrow G when a release lever 14 is actuated.

[0015] On the side of the connecting element 1 facing away from the clamping elements 3, 4, there is a handle 15 projecting from the drive housing 6 and a clamping lever 7, which can be pivoted against the handle 15 against the restoring force of a return spring. The clamping lever 7 forms a drive element. An arm of the drive element 7, projecting into the drive housing 6, acts against a drive body 16, which has a window through which the connecting element 1, formed from a flat steel, round steel, oval steel, or polygonal steel, projects. When the drive element 7 is pivoted, the drive body 16 tilts at the two narrow sides of the connecting element 1, preventing the drive body from moving relative to the connecting element 1. Further pivoting of the drive element 7 then leads to a movement of the drive housing 6 relative to the connecting element 1 in a clamping direction K.After the clamping force applied to the drive member 7 is released, a spring element 18 causes the drive body 16 to be moved back into its initial position, whereby the drive body 16 shifts relative to the connecting member 1.

[0016] To hold the drive body 16 of the drive housing 6 in position during this retraction, a locking element 2 is provided, which is held in a locking position by a spring element 17. In this position, two narrow edges of a window 8 are jammed against the narrow edges of the connecting member 1, preventing the drive housing 6 from being displaced in the direction of the opposing force G relative to the connecting member 1. Only by actuating the release lever 14, whose cam 19, located at the end of an arm, releases the locking element 2 from the locking position, is the retraction of the drive housing 6 in the direction of the opposing force G possible.

[0017] In a clamping position, the locking element 2 is subjected to deformation. This is a tensile deformation in the extension direction of the window 8. The two edges 10 of the window 8 are spaced apart depending on the clamping force K.

[0018] The window 8 is formed by a frame having two parallel frame legs 9, 9' which are subjected to tension in the clamping position. A sensor element 5 is located on one of these legs 9, 9'. Preferably, the sensor element 5 is a strain gauge. The strain gauge 5 can be affixed to the leg 9 of the frame that encloses the window 8. The sensor element 5 is located, in particular, between two lines defined by the two edges 10. The strain gauge is specifically positioned where the locking element is stretched by the transmission of the clamping force from the clamping element 4 to the connecting member 1.

[0019] Cables 12 may be provided to connect the sensor element 5 to an electrical device 11. The electrical device 11 may include a battery for power. The electrical device 11 may have a transmit / receive antenna for exchanging data with an external transmit / receive device 20 along a wireless communication link 13, 13'. Alternatively, an electrical contact (not shown) may be provided to establish a wired communication link with an external electrical device.

[0020] According to a preferred embodiment of the invention, the external electrical device, which forms a transmitting / receiving device, is formed by a mobile device, for example a tablet computer or a smartphone. In the Figure 1The mobile device is designated by the reference number 20. Values ​​measured by the sensor element 5 can be displayed on a screen 21 of the mobile device 20. In particular, the mobile device 20 is programmed such that a use case can be selected from a group of use cases. Each use case is assigned a limit value. This limit value can be a minimum clamping force, a maximum clamping force, or a range between a minimum and a maximum clamping force. The screen 21 can indicate whether the clamping force between the clamping elements 3 and 4 is within a valid range for the selected use case.

[0021] Applications include, for example, clamping various materials or workpieces. The indicator 21 can emit a signal, such as a visual or acoustic signal, when a minimum clamping force is undershot or a maximum clamping force is exceeded. The maximum permissible clamping force depends on the application, for example, on the type of material, such as the hardness of the wood being glued using the clamping tool. An application involving the gluing of soft woods may have a lower limit for the maximum clamping force than an application involving harder woods. The invention further relates to a method or use in which several clamping tools of essentially identical design communicate with an external transmitter / receiver 20.The display 21 of the transmit / receive unit 20 can then show all clamping forces exerted by the clamping tools on a workpiece. It can visually indicate which of the numerous clamping tools needs to be retightened or which clamping tool requires its clamping force to be reduced so that all clamping tools exert a uniform clamping force on the workpiece.

[0022] Several clamps can be arranged in a row, each applying a predetermined clamping force to a workpiece. Each clamp can emit a visual, audible, or other perceptible signal when the actual clamping force deviates from a target value, falls outside a target value range, falls below a target value, or exceeds a target value. The signals emitted can be differentiated in a suitable manner, allowing for identification of the clamp that emitted a signal when multiple clamps are present. For example, the audible signals can differ in pitch, tone sequence, or similar characteristics.

[0023] The foregoing statements serve to explain the inventions covered by the application as a whole, which each independently further develop the prior art at least through the following combinations of features, whereby two, several or all of these combinations of features may also be combined, namely:

[0024] A clamping tool characterized in that the deformable element is an element 2, over which one of the clamping elements 4 rests on the connecting member 1 in the clamping position.

[0025] A clamping tool characterized in that the element is a locking element 2 which can be moved from a locking position supported on the connecting member 1 into a release position, wherein the clamping element 4 which supports the locking element 2 on the connecting member 1 can be displaced in the release position in the direction of the counterforce G relative to the connecting member 1.

[0026] A clamping tool characterized in that the clamping element 4, which supports the connecting member 1 with the locking element 2, is associated with a drive housing 6, which in the release position can be displaced in the extension direction of the connecting member 1, wherein the drive housing 6 has a drive element 7, with which the drive housing 6 can be displaced stepwise in the direction of the clamping force K by a repetitive movement of the drive element and the locking element 2 forms a backstop.

[0027] A clamping tool characterized in that the sensor element 5 is a strain gauge which is attached to a surface of the locking element 2.

[0028] A clamping tool characterized in that the sensor element 5 is arranged on a leg 9 of a frame surrounding a window 8, wherein the connecting member 1 extends through the window 8.

[0029] A clamping tool characterized in that two opposing edges of the window 8 form edges 10 which jam in the locking position on the connecting member 1, wherein at least one of two legs 9, 9' connecting the two edges forming the edges 10 carries the sensor element 5, which is designed in particular as a strain gauge.

[0030] A clamping tool characterized in that an electronic device 11 is provided which evaluates the signals supplied by the sensor element 5 and determines a value of the clamping force K and / or transmits the signals and / or that the electronic device 11 is configured such that optical or acoustic signals generated by it from one clamping clamp are distinguishable from another clamping clamp used together with the first clamping clamp.

[0031] A clamping tool characterized in that a wired or wireless transmission link 13 is provided, with which the signals supplied by the sensor element 5 or the values ​​determined by the electronic device 11 can be transmitted away from the clamping tool to a transmitting / receiving device 20.

[0032] A method characterized in that data communication 13, 13' is established with a transmitting / receiving device 20, wherein the transmitting / receiving device 20 has a display 21 on which the values ​​of the clamping force K or values ​​derived therefrom are displayed.

[0033] A use of a clamping tool characterized in that the transmitting / receiving device 20 wirelessly receives data from the clamping tool and displays this or derived data on a display 21, wherein the transmitting / receiving device 20 is in particular a mobile terminal device 20, wherein it is particularly provided that several clamping tools transmit data to a common transmitting / receiving device 20 and the data or derived data are displayed on the display 21.

[0034] All disclosed features are essential to the invention (individually, but also in combination with one another). The dependent claims, even without the features of a referenced claim, characterize independent inventive developments of the prior art, particularly for the purpose of filing divisional applications based on these claims. The invention specified in each claim may additionally include one or more of the features described above, in particular those identified by reference numerals and / or listed in the reference numeral list. The invention also relates to designs in which individual features mentioned in the preceding description are not implemented, in particular to the extent that they are recognizably unnecessary for the respective purpose or can be replaced by other technically equivalent means. List of reference symbols 1 Connecting link 2 Blocking element G Counterforce 3 Clamping element K Tension 4 Clamping element 5 Sensor element 6 drive housing 7 drive element 8 Window 9 leg 9' leg 10 edge 11 Furnishings 12 Cable 13 transmission line 13' transmission line 14 Release lever 15 Handle 16 drive unit 17 spring element 18 spring element 19 cam 20 mobile device 21 Advertisement

Claims

1. Clamping tool comprising a device for generating a clamping position in which two clamping elements (3, 4) apply a clamping force (K) to a workpiece (G), the counterforce of which is absorbed by a connecting member (1) interconnecting the clamping elements (3, 4), the clamping tool further comprising an element which deforms when the clamping force (K) is generated, and a sensor element (5) which converts the deformation of the deformable element into an electrical signal from which a value of the clamping force (K) can be determined, characterized in that the deformable element is a blocking element (2) by means of which, in the clamping position, one of the clamping elements (4) is supported on the connecting member (1) in a blocking position, and which can be brought into a release position in which the clamping element (4) supported on the connecting member (1) can be displaced relative to the connecting member (1).

2. Clamping tool according to claim 1, characterized in that the clamping element (4) supported on the connecting member (1) by the blocking element (2) is associated with a drive housing (6) which, in the release position, is displaceable in the longitudinal direction of the connecting member (1).

3. Clamping tool according to claim 2, characterized in that the drive housing (6) comprises a drive member (7) by means of which the drive housing (6) can be displaced stepwise in the direction of the clamping force (K) by a repetitive movement of the drive member (7), and in that the blocking element (2) forms a back-drive lock.

4. Clamping tool according to any one of the preceding claims, characterized in that the sensor element (5) is a strain-measuring element which is fastened to a surface of the blocking element (2).

5. Clamping tool according to any one of the preceding claims, characterized in that the sensor element (5) is arranged on a leg (9) of a frame surrounding an opening (8), through which the connecting member (1) extends.

6. Clamping tool according to claim 5, characterized in that two opposite edges of the opening (8) form edges (10) which interlock with the connecting member (1) in the blocking position, and that at least one of the two legs (9, 9') connecting the edges (10) carries the sensor element (5), which is in particular designed as a strain gauge.

7. Clamping tool according to any one of the preceding claims, characterized in that an electronic unit (11) is provided which evaluates the signals supplied by the sensor element (5) and determines a value of the clamping force (K).

8. Clamping tool according to any one of the preceding claims, characterized in that an electronic unit (11) transmits signals supplied by the sensor element (5).

9. Clamping tool according to claim 7 or 8, characterized in that the electronic unit (11) is configured such that optical or acoustic signals generated thereby for one clamping tool are distinguishable from the signals generated by another clamping tool used together with the former.

10. Clamping tool according to any one of claims 7 to 9, characterized in that a wired or wireless transmission path (13) is provided, via which the signals supplied by the sensor element (5) or the values determined by the electronic unit (11) can be transmitted from the clamping tool to a transmitting / receiving device (20).

11. Method for operating a clamping tool according to any one of the preceding claims, characterized in that data communication (13, 13') is established with a transmitting / receiving device (20), wherein the transmitting / receiving device (20) comprises a display (21) on which the values of the clamping force (K) or values derived therefrom are displayed.

12. Use of at least one clamping tool according to any one of claims 1 to 10 together with a transmitting / receiving device (20), characterized in that the transmitting / receiving device (20) wirelessly receives data from the clamping tool and displays these data or data derived therefrom on a display (21), the transmitting / receiving device (20) being in particular a mobile terminal (20), wherein it is in particular provided that several clamping tools transmit data to a common transmitting / receiving device (20) and the data or the data derived therefrom are displayed on the display (21).

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