Clamping tool

Abstract

Clamping tool with a clamping jaw, in particular in the form of a punch (13), arranged at the end of a rod, in particular a push rod (12), which is slidably arranged in a base body (6), which can be advanced in a clamping direction by means of a step-shift mechanism (8, 9, 10, 11) and with a releasable backstop (14, 15, 16, 17, 18, 19) having a locking element (16) in a locking position against a support stop (19) to prevent the rod (12) from being advanced backwards in the opposite direction to the clamping direction, characterized by a movement end stop (20) spaced apart from the support stop (19), against which the locking element (16) abuts when the rod (12) is advanced in the clamping direction and from which it is released after the advance by pressure on the clamping jaw,in particular the punch (13) or by the force of a return spring (17) accompanied by a reversal of the rod in the opposite direction to the clamping direction until it reaches a stop position on the support stop (19).

Description

[0001] The invention relates to a device according to the generic term of claim 1.

[0002] Such a device is described in DE 42 31 418 A1. A rod mounted in a base body can be advanced in one clamping direction by actuating a stepping mechanism. A releasable backstop, formed by a pivotally mounted clamping lever, prevents the rod from being advanced backwards in the opposite direction to the clamping direction. If a release lever is actuated, the rod can be advanced backwards in the opposite direction to the clamping direction.

[0003] A similar device is described in WO 2005 / 097354 A1. Here, a locking plate is mounted on an axis in a pivoting manner.

[0004] US patent 2007 / 0181607 A1 also describes a device in which a rod can be advanced in a clamping direction by means of a stepping mechanism. A backstop prevents the rod from being advanced in the opposite direction.

[0005] The invention is based on the objective of further developing the generic device in a way that is advantageous for use.

[0006] The problem is solved by the invention specified in claim 1.

[0007] To solve the aforementioned problem, the backstop is designed so that, after a forward movement, it only engages after a slight backward movement. This is particularly advantageous when the clamping tool is a cartridge dispensing device. The plunger compresses the pasty substance stored in the cartridge and forces it out of the outlet. If the aforementioned actuator is relieved of the drive force on the propulsion lever, the force of the compressed substance causes a slight backward movement of the plunger or push rod before this movement is inhibited by the backstop. This allows the pasty substance compressed in the cartridge to expand, thus preventing dripping from the outlet. The locking element of the backstop can be spaced apart from a support stop after the initial movement.Only after the forward movement is complete can pressure on the clamping jaw, i.e., the plunger, move the rod back to a position where the locking element rests against the support stop. An end-of-travel stop may be located adjacent to the support stop, against which the locking element rests to engage its locking position, in the direction of forward movement. The locking element may strike this end-of-travel stop if it is carried a short distance along the clamping direction during the forward movement of the push rod. This can occur simultaneously with compression of the return spring. However, it is also possible for the locking element to be acted upon by a drive spring in the area of ​​the support stop or the end-of-travel stop in the clamping direction, and for this drive spring to develop a greater spring force than the return spring, so that the locking element remains permanently in contact with the end-of-travel stop.In this variant as well, it is possible to slightly retract the piston or push rod after the drive has been completed by actuating the drive lever. A release lever, located in front of the handle or drive lever in the direction of the rod's drive, can be used to release an edge section of the locking element. This edge section is opposite the edge section that has some play between the end stop and the support stop.

[0008] An embodiment of the invention is explained below with reference to the accompanying drawings. These show: Fig. 1 in perspective view an embodiment of a cartridge ejection device; Fig. 2. a cut according to the section line II - II in Fig. 1; Fig. 3 an exploded view of the essential elements of the cartridge ejection device; Fig. 4 another perspective view of the cartridge ejection device in the area of ​​an insertion opening 38 for a cartridge tube 1 of a cartridge; Fig. 5 a cut according to the line V - V in Fig. 4, wherein the end of a cartridge tube 1 is held in a clamping position; Fig. 5a a representation according to Fig. 5, whereby the cartridge tube has been released; Fig. 6. a cut according to line VI - VI in Fig. 5a; Fig. 7 a representation according to Fig. 2 with the drive lever 8 actuated in the direction of forward motion; Fig. 8 a subsequent presentation according to Fig. 7, wherein the piston 13 or the push rod 12 has been moved back slightly to a locking position; Fig. 9 a representation according to Fig. 2 with the backstop in the release position and Fig. 10 a second embodiment.

[0009] The in the Fig. The embodiment shown in Figures 1 to 9 has a base body 6 made of plastic, which has an insertion opening 38 at its front end for inserting a cartridge tube 1 of a cartridge filled with a pasty substance. Inside the cartridge tube 1 is a piston 2. On the side opposite the piston 2, the cartridge forms an outlet opening 4 with a nozzle 5, through which a pasty substance 3 stored inside the cartridge can be forced out by pressing on the piston 2.

[0010] To receive the end 1' of the cartridge tube 1, an annular base 21 is provided in the area of ​​the bottom of the insertion opening 38. The wall of the insertion opening 38 is formed by an inner cylinder. Two diagonally opposite areas of the base 21 are formed by webs extending along a circular arc contour line, which have radially inwardly extending support ribs 26. The course of the wall 22 of the base 21 corresponds there to the inner contour of the cartridge tube 1. On two diagonally opposite sides, where no clamping means are provided, the base 21 has flattened sections 21'.

[0011] In the center of the base 21 is a guide opening 23 in which a push rod 12 is mounted. At its front end, which projects into the insertion opening 38, this rod carries a plunger 13, which can actuate the piston 2 in a clamping direction. The push rod 12 can be moved stepwise in the clamping direction by means of a stepping mechanism, which will be described below. It is prevented from moving backwards by a backstop, which will also be described below.

[0012] With respect to the push rod 12, the housing 6 forms two diametrically opposed chambers 36 adjacent to the insertion opening 38. The chambers extend parallel to the insertion opening 38. An actuating lever 27 is mounted in each of the two chambers 36. The two axes of rotation 33, about which each actuating lever 27 can rotate, run parallel to each other. Each actuating lever 27 forms an actuating arm 28 projecting in the opening direction of the insertion opening 38. The actuating arms 28 can be moved towards each other. This occurs against the restoring force of a compression spring 29, which is supported on the bottom of a cup-shaped opening 34. The other end of the compression spring 29 acts on the underside of the actuating arm 28. In a 180° extension direction relative to the actuating arm 28, the actuating lever 27 has a locking arm 37. The chamber 36 is closed to the outside by the actuating arm 28 and the locking arm 37.

[0013] A clamping arm 30 projects from the rear of the lever pair 28, 37. At the end of this clamping arm is a clamping piece 31 made of a metal plate. The metal plate extends obliquely to the direction of movement of the push rod 12 and has a cutting edge 32 at its free end, running along an arc. The compression spring 29 exerts a force that causes the cutting edge 32 to act obliquely into the outer wall of the cartridge tube 1. Due to the oblique position of the clamping piece 31, which has the cutting edge 32, the cutting edge digs into the outer wall of the cartridge tube 1 when the cartridge is pulled, which is caused by a forward movement of the plunger 13.

[0014] The clamping connection that holds the cartridge tube 1 to the base body 6 can be released with one hand. The two actuating arms 28 of the actuating levers 27 can be moved towards each other using the thumb and forefinger. With the other hand, an empty cartridge can be pulled out of the insertion opening 38.

[0015] To insert a new cartridge, the actuating arm 28 does not need to be actuated. Due to the angled position of the clamping piece 31, it is displaced from the front edge of the end 1' of the cartridge tube 1 when a new cartridge is inserted into the insertion opening 38.

[0016] The step-shift mechanism mentioned above consists of a drive lever 8, which is mounted on the base housing 6 about a housing-fixed axis 24. The drive lever 8 can be pivoted towards the handle 7 by the fingers of a hand gripping a handle 7. As this happens, a drive arm of the drive lever 8 moves in the opposite direction and acts on the edge of a driver 10 mounted in a bearing chamber 39. The driver 10 is a metal plate with a sharp-edged opening 10', through which the push rod 12 passes. A return spring 11, also through which the push rod 12 passes, acts on the driver 10 and holds it in a home position in which the push rod 12 can slide freely through the opening 10' of the driver 10.When the drive lever 8 is pivoted, the action of the drive arm 9 on the edge of the driver 10 causes the driver 10 to tilt, so that the sharp edges of the opening 10 engage in the outer wall of the push rod 12. The push rod 12 is thus coupled to the driver 10 and is dragged along by the driver 10 against the restoring force of the return spring 11 in the clamping direction. The plunger 13 located at the end of the push rod 12 thereby acts on the piston 2 of the cartridge. With this type of forward displacement of the push rod 12, as described in the... Fig. As shown in Figure 7, a locking element 16, also formed from a steel sheet, is displaced. A return spring 17, which acts on an edge section of the locking element 16, is compressed. During the forward displacement, an edge section of the locking element 16 rests against a movement end stop 20 of the base body 6, which is associated with the side of the locking element 16 facing away from the opening 16' of the return spring 17.

[0017] Will - as in the Fig. Figure 8 shows that when the drive lever 8 is relieved of pressure, allowing the driver 10 to move slightly in the opposite direction, the pasty mass 3 inside the cartridge can expand. This is accompanied by a slight retraction of the piston 2 or the plunger 13. The retraction path is limited by the support stop 19, which is positioned at a distance opposite the end stop 20. Between the support stop 19 and the end stop 20 is a section of the locking plate 16 with some play.

[0018] When the locking plate 16 is moved to its stop position against the support stop 19, a torque acts on the locking plate 16, which is maintained primarily by the return spring 17, but also by a force acting on the push rod 12. Since the push rod 12 is in a clamped position in the opening 16', it cannot be moved against the feed direction.

[0019] This lockable position is in the Fig. 8 shown. It can be moved by pivoting a release lever 14 into the position shown. Fig. The position shown in Figure 9 is released. The release lever 14 is pivoted about its pivot axis 25, so that the edge section of the locking member 16, acted upon by the return spring 17, is displaced from an actuating shoulder 15. This tensions the return spring 17 and pivots the locking member 16 about the support stop 19 until the push rod 12 can slide freely through the opening 16'.

[0020] In the area of ​​the edge section of the locking element 16, which lies with play between the support stop 19 and the end stop 20, a drive spring 18 acts on the locking element 16. The direction of action of the drive spring 18 is opposite to the direction of action of the return spring 17 and acts on the locking element 16 in the direction towards the end stop 20. If the spring force of the drive spring 18 is greater than the spring force of the return spring 17, the locking element 16 is permanently in contact with the end stop 20. By applying pressure to the push rod 12 against the direction of tension, the push rod can therefore be moved back by the amount of play against the direction of tension until the locking element 16 abuts the support stop 19.

[0021] If the return spring 17 is stronger than the drive spring 18, the push rod 12 will not be held in the end position of the stroke after the drive lever 8 has completed a drive stroke. Instead, the push rod will be actively moved back into the restoring-locked position by the force of the return spring 17.

[0022] In the Fig. In the embodiment shown in Figure 10, the punch 13 is moved by a telescopic thrust device (not shown) which is movable by an electric drive 40. For this purpose, batteries 6 and a gearbox driven by a drive motor are provided within the base body. The motor begins to rotate, which is accompanied by a linear displacement of the punch 13 (not shown), when a push button 41, which is arranged in a handle opening associated with a handle 7, is actuated.

[0023] The base housing 6 also contains a level indicator, formed by a pointer 45 guided in a slot 46 of the housing 6. A scale 44 is provided along the slot 46.

[0024] The cartridge is held by a clamping device similar to the one used in the Fig. 1 to 9 is provided on a hand-operated ejector device, which has been described in detail above.

Claims

[1] Clamping tool with a clamping jaw, in particular in the form of a punch (13), arranged at the end of a rod, in particular a push rod (12), which is slidably arranged in a base body (6), which can be moved forward in a clamping direction by means of a step-shift mechanism (8, 9, 10, 11) and with a releasable backstop (14, 15, 16, 17, 18, 19) having a locking element (16) which rests against a support stop (19) in a locking position to prevent the rod (12) from moving backward in the opposite direction to the clamping direction, characterized bya movement end stop (20) spaced apart from the support stop (19), against which the locking element (16) strikes during the forward movement of the rod (12) in the clamping direction and from which it moves away after the end of the forward movement by pressure on the clamping jaw, in particular the punch (13) or by the force of a return spring (17) accompanied by a retraction of the rod in the opposite direction to the clamping direction until it reaches a stop position on the support stop (19). [2] Clamping tool according to claim 1, characterized by , that the locking element (16) is a clamping plate with an opening (16') through which the rod (12) is guided. [3] Clamping tool according to claim 1 or 2, characterized by , that the locking element (16) is held in a clamping position relative to the rod (12) by a return spring (17). [4] Clamping tool according to one of claims 1 to 3, characterized by, that the locking element (16) is acted upon by a drive spring (18) in the forward displacement direction, with which the locking element (16) is acted upon against the movement end stop (20). [5] Clamping tool according to any one of claims 1 to 4, characterized by a release lever (14) for releasing the backstop (14 to 19). [6] Clamping tool according to claim 5, characterized by , that the return spring (17) acts on the end of the locking plate (16) where an actuating shoulder (15) of the release lever (14) also acts, and that in the area of ​​the opposite end of the locking plate (16), which interacts with the support stop (19) and the movement end stop (20), the drive spring (18) acts.

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