DE4332710A1 - Hand pliers for assembly purposes - Google Patents

Abstract

The hand pliers are especially suitable for sliding sleeve type pipe-connecting systems for metallic and non-metallic pipes. They comprise essentially two pliers parts which are held together by a first hinge joint (1), each part of which is formed from a front limb for holding in each case one assembly jaw (17 and 18 respectively) and a rear handle limb (2 and 3 respectively) which is many times longer. In this arrangement, one of the two handle limbs (2 and 3 respectively) is divided into an inner, shorter handle part (19) and an outer, longer handle part (20). This outer handle part (20) forms, with a chain wheel (24) and a tension chain (27), a link mechanism for the purpose of achieving a greater assembly force. To turn the chain wheel (24) and thus tighten the hand pliers, use is made of a ratchet wheel (25) with ratchet teeth. Furthermore, a pawl (39) engages in the ratchet teeth (38) and prevents the handle limbs (2, 3) from springing back during the gripping operation. To release the pawl (39), a sliding plate (46) movable to and fro is provided. <IMAGE>

Description

The invention relates to a hand tool for Assembly purposes, especially for Sliding sleeve pipe connection systems, according to the Preamble of claim 1.

Such a pair of pliers is from DE 36 17 529 T2 known. By the provided with this hand tool Articulated mechanism in connection with a tension chain is for the clamping movement compared to one usual pliers with the same dimensions one by one Many times higher overall gear ratio and thus a correspondingly higher assembly force can be achieved. Should not be such a hand tool for mounting metallic pipe systems with larger nominal widths are used are relatively high To apply assembly forces. It can be because of Self-elasticity and above all because of the inevitable Tolerances of the interconnected joint parts come that a "spring open" during the tensioning movement takes place and the catch is not in the next tooth gap can occur, so that another Increasing the tension is no longer possible. Here the invention seeks to remedy the situation.

The object of the invention is accordingly in the well-known hand tool for assembly purposes improve and educate, especially in that that even with extremely high assembly forces Manual pliers continuously without problems until they are reached  the end position can be closed without the There is a risk of springing open.

This task is the beginning of a pair of pliers mentioned type according to the invention solved in that the Ratchet wheel over its entire circumference Pawl teeth that one with this Interlocking, spring-loaded teeth Locking pawl is provided, which is a rotation of the Ratchet wheel allows when tightening the pliers, however its reverse rotation prevented, and that at the Locking pawl accessible from the outside Actuator is attached, by means of which the Locking pawl from its engaged position is temporarily swingable into an exemption.

Advantageous further developments are in the Subclaims described.

After a first advantageous training is on the locking pawl as an actuator a cross standing pin attached in a slot of the inner grip part is guided and with its free End protrudes from the wall of the handle part.

The locking pawl is advantageously on one Bolt pivoted on the inner handle and the exposed to constant action of a compression spring, the to hold the locking pawl in the engaged position is looking for.

According to another advantageous development, a Guide the chain provided that an unwanted Prevent lifting from the teeth of the gear.  

For this purpose, in the area where the chain is on Gear is present, a fixed sliding block in the inner handle part attached, with play of the chain is adjacent.

Another advantageous development of the hand tool relates to a measure to facilitate the Unlocking the pawl. For this purpose, on outer handle part a sliding tab with a limited sliding back and forth stored in their starting position with the Face of the pin is adjacent. To hold and Guide the sliding tab are useful two spaced elongated holes, in each of which a Handle part held bolt is guided. One of these two bolts can advantageously by one axial extension of the hinge pin are formed.

The driver pawl can, if necessary is, with the help of the sliding tab in an exemption be pivoted. For this purpose, according to one Further development of the invention on the one hand Driver pawl attached a cross pin and the other on the sliding tab on its inner long side Molded nose during the back movement of the Sliding tab acts on the cross pin so that the driver pawl from its engaged position in one Exemption is movable.

The main advantage of the invention can be achieved is that during the period of Closing movement during which the required high Applying resilience is not the danger of a Open or snap back. this will  rather prevented by the locking pawl, which at a clamping movement automatically into the individual Gaps in the teeth of the pawl engages. To this The clamping process can be done in any way Intermediate positions can be easily interrupted. Of The advantage is that the previously generated contact pressure in remains essential, so that there is no danger there is that the assembly pliers with their assembly jaws slips off the pipe connection parts. The weight loosing the hand tool after installation has been completed simple way in that the locking pawl with Help the pin stick out from the side Locking position is pivoted out. The further The provided sliding jaw offers an additional one Security against possible slipping up Tension chain.

During the handling of the pliers, with the hands of the user can capture a handle part, if this is desired by pressing the thumb Sliding tab moves and thus the locking pawl be unlocked. Unlocking can thus from the Use position of the respective hand, d. H. without temporary release of a grip part. This advantage is equally for a swing out given the driver pawl if during use temporarily remove the driver pawl from the hand tool Intervention should be.

An embodiment of a hand tool according to the Invention is shown in the drawing and will explained in more detail below. It shows:

Fig. 1 is a side view of the hand tool in the closed position,

Fig. 2 is a side view of the hand tool in the open position,

Fig. 3 is a side view in the region of the second articulation as a detail of FIG. 2 on a larger scale and

Fig. 4 is an end view of the second articulated connection from the inside.

The illustrated pliers contain two pliers parts held together by an articulated connection with a bolt 1 , each of which has a grip leg 2 , 3 . The two pliers parts usually consist of U-shaped sheet metal profiles, which face each other with their open sides. On the head part of the pliers, the sheet metal profiles are fork-shaped, the legs of the handle part 3 receiving the legs of the opposite handle part 2 between them. The hinge pin 1 is held axially secured in aligned bores of the fork legs.

At the free ends of the pairs of forks a base body 4 or 5 is held in an articulated manner with the aid of a supporting bolt 6 or 7 . At the inwardly projecting ends, a guide bar 8 or 9 with an inner straight support surface 10 or 11 is formed on the jaw base bodies 4 or 5 . Each support surface 10 or 11 rests on a pin 12 or 13 held in the respective handle leg 2 or 3 as a counter bearing. The axes of the support bolts 6 , 7 and the pins 12 , 13 form the articulation points of a four-bar linkage. A tension spring 14 acting on the ends of the guide strips 8 , 9 has the task of holding the guide strips 8 , 9 in their contact position on the pins 12 and 13, respectively. When opening and closing the hand tool, the jaw base bodies 4 , 5 move while maintaining their parallel position to one another.

In the two jaw base bodies 4 and 5 , at their free ends, there is a blind groove 15 and 16 with a dovetail profile that runs transversely to the direction of movement, as can be seen from the drawing. The blind grooves 15 and 16 start from opposite sides of the jaw base bodies 4 , 5 and are open at the top.

An interchangeable mounting jaw 17 or 18 can be attached to each of the jaw base bodies 4 or 5 with the aid of a profile attachment corresponding to the blind groove 15 or 16 . Each mounting jaw 17 or 18 contains a U-shaped receiving channel, which hold the pipe connection parts between them during assembly, which are moved axially against one another during the production of a pipe connection with the aid of the assembly pliers and are thereby pressed onto the pipe connection.

By having assembly jaws 17 , 18 with receiving channels with different internal widths and profile shapes ready, the hand tool for sliding sleeve pipe connection systems with different nominal widths and designs can be used universally.

While the handle leg 2 is continuous, the other handle leg 3 , which corresponds in shape to the handle leg 2 near the head of the pliers, is divided into an inner, shorter handle part 19 and an outer, longer handle part 20 , which are connected by a second joint are hinged together with a bolt 21 . At the opposite ends of the handle parts 19 , 20 , the outer handle part 20 is designed as a fork, the fork legs 22 receiving the free end of the inner handle part 19 between them. The hinge pin 21 is axially immobile in aligned bores 23 of the legs of the two handle parts.

As can be seen in particular from FIG. 4, the hinge pin 21 is at the same time also a bearing pin for a chain wheel 24 and a ratchet wheel 25 with circumferential toothing which is connected to it in a rotationally fixed manner. Sprocket 24 and ratchet wheel 25 are non-rotatably seated on a sleeve 26 , which extends in its axial length with little play between the legs of the inner handle part 19 . Sprocket, ratchet wheel and sleeve can also be formed in one piece.

A chain 27 , preferably a link chain, is guided over the chain wheel 24 and is attached at one end to the handle leg 2 on a pin 28 . In the other direction, the chain 27 runs inside the U-shaped outer grip part 20 , its free end being attached to the grip part 20 via a tension spring 29 . The tension spring 29 serves to tighten the unloaded section of the chain 27 .

In the foot region of the fork of the outer handle part 20 , a ratchet pin 31 is mounted in bores in its legs 30 , which is secured in a suitable manner against axial displacements. This ratchet pin 31 carries in the plane of the ratchet wheel 25 a driver pawl 32 which can engage with a nose 33 in a circumferential toothing 34 of the ratchet wheel 25 . A retaining spring 35 acts on the pawl 32, which seeks to keep the pawl 32 in its engaged position with the ratchet 25th

As shown in FIGS. 2 and 3, the outer grip part 20 can be pivoted outwards from its rest position according to FIG. 1 relative to the inner grip part 19 into an end position which is limited by a stop. This stop is caused by the abutment of the end faces of the webs of the U-shaped profiles of the two handle parts. Before reaching the end position of the pivoting movement of the outer handle part, the driver pawl 32 is automatically pivoted from the engagement position into an exemption. For this purpose, an overhanging lug 36 is formed on the web of the inner grip part 19 , with which the inner sliding surface 37 of the driving pawl comes into pressure contact at the beginning of the final phase of the pivoting movement.

During the opening movement of the hand tool, the outer handle part 20 first swivels into the end position shown in FIG. 2. Only then does a spreading movement of the handle parts 2 and 19 take place, and thus the mounting jaws 17 , 18 move apart. Conversely, when the hand pliers are closed, the aforementioned handle parts are first pressed against one another until the mounting jaws 17 , 18 come into contact with the pipe connection parts. The pivotal movement of the outer grip part 20 then begins, the driver pawl 32 being released and thus being able to engage with its nose 33 in the toothing 34 of the ratchet wheel 25 . With the further movement of the outer handle part 20 , the ratchet wheel 25 and thus also the chain wheel 24 - based on the illustration in FIG. 2 - are now rotated clockwise. As a result of the rotation of the chain wheel 24, it moves along the chain 27 , as a result of which the chain section between the anchoring 28 and the chain wheel 24 is subjected to tension. This tensile load affects the handle leg 1 and the inner handle portion 19 with the result that they are pressed against each other in the sense of a closing movement of the hand tool.

During the closing movement of the outer handle part 20 , a two-armed lever is effective, of which one arm, namely the arm between the pivot axis of the pivot pin 21 and the pitch circle of the chain wheel 24 , is relatively short and the other arm, which extends from the pivot axis to the handle end of the handle part 20 extends, is significantly longer. In the case of hand-held pliers with customary dimensions, the ratio of these effective lever arms can be 1: 6 or more, for example. Accordingly, the achievable assembly force increases six times or more compared to a conventional hand tool.

With the help of the following devices, an automatic locking is effected during tensioning of the hand pliers and thus an unwanted "springing open" is prevented. On the circumferential side facing away from the driver pawl 32 , a locking pawl 39 is provided which interacts with the circumferential toothing of the ratchet wheel 25 . The locking pawl 39 is mounted on a fixed bolt 40 in the interior of the handle part 19 to a limited extent and contains a locking tooth 41 at its free end which can engage in the gaps in the toothing 38 . The locking pawl 39 is under the action of a compression spring 42 , which tries to keep the locking pawl 39 in its engaged position. Locking tooth 41 and toothing 38 are shaped such that the locking pawl 39 permits rotation of the ratchet wheel 25 in a clockwise direction - based on the illustration in FIG. 3 - but prevents counter-rotation.

On the locking pawl 39 , a pin 43 is fastened, which is guided in an arcuate slot 44 of the inner handle part 19 . By grasping the pin 43 , the locking pawl 39 can be temporarily pivoted out of its engagement position into a release, in order to be able to release the live parts of the pliers after a tensioning process has ended.

Furthermore, a fixed sliding jaw 45 is attached in the inner handle part 19 , which is adjacent to the chain 27 with play in the circumferential area in which the chain 27 rests against the chain wheel 24 , and thus prevents the chain 27 from sliding up while it is under tension is.

As already mentioned, the locking pawl 39 is pivoted out of the locking position into the release position by hand by moving the pin 43 . In order to be able to unlock the handle part 20 without releasing the hand, a type of remote control is provided. This consists essentially of an elongated sliding tab 46 , which is mounted laterally on the outer handle part 20 back and forth. Two elongated holes 47 and 48 are used to guide and hold the sliding tab 46 , with which the sliding tab 46 is guided at its outer end on a fixed pin 49 and at its inner end on the articulated pin 21 . The bolt 49 contains a flat head with a larger diameter so as to prevent the sliding tab 46 from slipping off unintentionally. The hinge pin 21 is axially extended in accordance with the strength of the sliding tab 46 . The cohesion is brought about by a removable snap ring 50 .

The inner end face of the sliding tab 46 is designed as a curved sliding surface 51 , which is adjacent to the pin 43 in the starting position of the sliding tab 46 . In order to be able to grasp the sliding tab 46 better, the free end is bent into a high leg 52 .

During the handling of the pliers, in which the hands of the user each grasp a grip part, the push tab 46 can be pushed upward from its initial position as shown in FIG. 1 by pressing with the thumb, the sliding surface 51 gripping the pin 43 and moved it in its slot guide in the other end position, in which the locking pawl 39 is disengaged. Likewise, the sliding tab 46 can be moved back into its starting position with the thumb, whereby the locking pawl 39 swivels back into the engagement position due to the action of the restoring force of the spring 42 .

Unlocking the locking pawl 39 inevitably creates a load on the driving pawl 32 , which can result in the driving pawl 32 not automatically pivoting into the release. In order to be able to pivot the driver pawl 32 by hand in such cases, a cross pin 53 is attached to the driver pawl 32 . In the exemplary embodiment, the transverse pin 53 serves at the same time for fastening the retaining spring 35 , which is designed as a tension spring and is held at its other end on a pin 54 attached in the transverse part 20 .

The pivoting of the driver pawl 32 can also be effected with the aid of the sliding tab 46 , which for this purpose is provided with a nose 55 on its inner longitudinal side. During the return movement of the sliding tab 46 , the nose 55 abuts the pin 53 and thus causes the driver pawl 32 to pivot out into the release position.

At extremely high loads, the force exerted by the sprocket 24 on the chain 27 is correspondingly high, and the resulting pressure on the teeth can result in the rear strand of the chain 27 , which runs in the handle part 20 , not being properly removed from the sprocket 24 replaces. To ensure detachment, a type of slide rail 56 is therefore fitted inside the handle part 20 , which runs parallel to the rear strand of the chain 27 with a straight slide surface 57 . The slide rail 56 serving as a chain deflector is held with a bore and a recess at its rear end on the one hand on the pawl pin 31 and on the other hand on the pin 54 .

Claims (8)

1. Hand tool for assembly purposes, in particular for sliding sleeve pipe connection systems for metallic and non-metallic pipes, with two pliers parts held together by a first articulated connection, each part of which is formed from a front leg for holding a mounting jaw and a multiple longer rear handle leg, one of which of the two handle legs is divided into an inner shorter and an outer longer handle part, and these two parts are articulated to one another by a second articulated connection with an articulated pin that is axially parallel to the first articulated connection, with a chain wheel and a ratchet wheel connected non-rotatably connected axially on the articulated pin are rotatably mounted with external toothing, the sprocket engaging in a chain, which is attached at one end to the opposite one-piece handle leg, from here is guided around the sprocket on the outside, along the outside Handle part of the other handle leg continues and is held with its free end via a tension spring in the handle leg and a spring-loaded driver pawl is mounted on the outer handle part such that when the outer handle part closes, the ratchet wheel and chain sprocket perform a closing movement of the pliers, thereby characterized in that the ratchet wheel ( 25 ) has ratchet toothing ( 34 , 38 ) running over its entire circumference, that a spring-loaded locking pawl ( 39 ) cooperating with this toothing is provided, which permits rotation of the ratchet wheel ( 25 ) when the pliers are tensioned but prevents the reverse rotation and that (39) a is attached externally accessible actuator (43) on the locking pawl by means of which the locking pawl (39) can be swung from its engaged position in temporary exemption. 2. Hand tool according to claim 1, characterized in that a transverse pin ( 43 ) is attached to the locking pawl ( 39 ), which is guided in an elongated hole ( 44 ) of the inner handle part ( 19 ) and with its free end against the wall of the handle part ( 19 ) protrudes. 3. Hand tool according to claim 1 or 2, characterized in that the locking pawl ( 39 ) on a bolt ( 40 ) on the inner handle part ( 19 ) is pivotally mounted and is under the action of a compression spring ( 42 ). 4. Hand tool according to one of claims 1 to 3, characterized in that in the peripheral region in which the chain ( 27 ) abuts the sprocket ( 24 ), a fixed sliding jaw ( 45 ) is provided, which with play of the chain ( 27 ) is adjacent. 5. Hand tool according to claim 2, characterized in that on the outer handle part ( 20 ) laterally a sliding tab ( 46 ) with an end sliding surface ( 51 ) is mounted to move back and forth and that the sliding tab ( 46 ) in the starting position with its sliding surface ( 51 ) the pin ( 43 ) is adjacent. 6. Hand tool according to claim 5, characterized in that the sliding tab ( 46 ) has at least two elongated holes ( 47 , 48 ) and is guided by means of these elongated holes ( 47 , 48 ) on a bolt held on the handle part ( 21 , 49 ). 7. Hand tool according to claim 6, characterized in that one of the two bolts is formed by an axial extension of the hinge pin ( 21 ). 8. Hand tool according to one of claims 5 to 7, characterized in that on the driver pawl ( 32 ) a cross pin ( 53 ) is fixed and that the sliding tab ( 46 ) on its inner longitudinal side has a nose ( 55 ) which during the return movement the sliding tab ( 46 ) acts on the cross pin ( 53 ) in such a way that the driver pawl ( 32 ) can be moved into an exemption.