DE1615840B2 - CLAMPING PLIERS FOR ELECTRICAL CONNECTORS - Google Patents

Description

The subject of the present invention is a clamp for electrical connection parts with several Form elements, a pair of pliers-like handles, a first stop member on one of the Handles, a second stop member on the second handle, a support member attached to one of the Stop members is attached, and is movable into engagement with the other of the stop members to the Support handles and prevent their further closing after they have reached a predetermined level Closing distance have been closed.

The purpose of the present invention is to provide a tool for making electrical connections to propose by squeezing, the clamping or squeezing depth being adjustable.

With the US-PS 30 39 337, 31 99 335 and 32 26 968 a pinch or described above is already Clamping tool has been proposed. In the arrangements shown there, however, the setting is the Squeezing or clamping depth is relatively complicated and these are difficult to manufacture to manufacture.

The invention is based on the object of providing clamping pliers for electrical connection parts, which is characterized by a simple adjustment of the squeezing depth.

The object is achieved according to the present invention by means of clamping pliers of the type mentioned at the beginning solved, which is characterized by a screw adjustment in a handle with which the first Stop member is adjustable in the longitudinal direction in the first handle to change the closing distance, and the contains interlocking threaded parts, one with the first stop member and the other with is coupled to the first handle.

An essential feature of the present invention is that the same components that are used as a stop when Actuating the pliers are also used to adjust the crimping depth. An assembly is thus used for two different purposes.

In addition, the crimping depth can now be set significantly more precisely than if two separate ones Assemblies are necessary for this, namely one to limit the movement of the handles to one another, and another to adjust the crimp depth.

Another advantage of the present invention is to be seen in the fact that a screw is used to adjust the crimping depth. This enables a very fine and stepless setting to be achieved.

Further features of the present invention form the subject of the subclaims. Particularly It should be emphasized that the support member is also used as a locking mechanism, whereby a Separating the handles before the point of movement is prevented at which the full desired Crushing depth is reached. The construction according to the invention is a great simplification here achieved. The essential feature of the present invention is that the release point of the locking mechanism Both functions remain unchanged at the anchor point in contrast to that of separate components are done, so there would be the risk that the two points in their relative situation were changing.

The invention is based on various exemplary embodiments with reference to the drawings described in more detail. It shows

F i g. 1 is a perspective view of a continuously adjustable hand-held clamping tool in accordance with the present invention Invention;

F i g. Fig. 2 is a sectional view taken along line 2-2 in Fig. 1;

F i g. 3 through 6 are partially sectioned and partially cut-away views of the ratchet mechanism the in F i g. 1 and 2 shown device in different working positions;

F i g. 7 is a top plan view of a component of the FIG. 3 to 6 shown mechanism;

F i g. 8 is a side view, partially broken away, of the FIG. 3 assembly shown;

F i g. 9 is similar to FIG. FIG. 2 is a partially broken away sectional view of an embodiment of the FIG Step adjustable tool constructed in accordance with the present invention;

Figure 10 is a sectional view taken along line 10-10 from F i g. 9;

F i g. 11 is a partially schematic enlarged view View of part of the assembly shown in Figure 9;

FIG. 12 is a view of another part of the FIG F i g. 9 assembly shown;

Figure 13 is a sectional view taken along line 13-13 from F i g. 9.

The in Fig. 1 and 2 shown squeezing tool 20 is continuously adjustable. It is also controlled by cams actuated, d. i.e., the movement of the handles towards each other actuates cams, which crimps or punches drive into the connector to crimp it onto a conductor.

The crimping tool 20 includes a first handle 22 and a second handle 24. Plastic coatings 44 and 46 cover the lower portions of the handles 24 and 22, respectively, to provide a soft, insulated one To create a handle for the user of the tool. As is particularly evident from Figure 2, the Handle 22 has an annular head part 25 with four inner curved cam surfaces 26. A cylindrical punch holder 28 forms the head part of the other handle 24. The holder 28 is in the Bore fitted in the head part 25 of the handle 22 and is symmetrically shaped with four Stamp holding slots 30 provided.

A cam follower 32 and a compression spring are mounted in each of the slots 30. A stamp part 34 isj an attached to each of the cam followers 32. Each stamp part 34 has a tip which extends into a central one opening 35 in the holder 28 extends.

Handles 22 and 24 are shown in the closed position; h, the handles are like this close together as possible. In fact, the use of the crimping tool begins with the one apart Handles and retracted punches 34. Then a wire with a loose on its end attached connecting part introduced into the central opening 35 and the handles 22 and 24 are through an operator is compressed into the position shown in the drawings. The squeezing the handle causes the cam surfaces 26 to act on the cam followers 32 to engage the punch members 34 to press into the connector and to squeeze it onto the wire. When the handles are released the springs in the slots 30 urge the cam followers 32 into the enlarged portion of the cam surfaces 26 and the punch are pushed away from the connector so that it is out of the crimping tool can be removed.

The punch holder 28 (not shown in FIG. 1)

5 6

is assembled with the help of four bolts 36 and the matching "locking block" 74, which is referred to herein.

Nuts held in the handle 24. One clamp fits. A ratchet mechanism 76 is with the aid

Screw 40 attaches a holder 42 for a bolt 78 pivotably on the locking block 74

Connection part with the help of a retaining plate 38 attached to the. The ratchet mechanism 76 includes one

Handle 24. By loosening the clamping screw 40, 5 rack 80, which in a longitudinal direction with

in a known manner, the part 42 slides in the longitudinal direction on the housing 82 provided with a pawl, which with

Pinch opening 35 can be moved towards and away from it, by means of bolt 78 pivotable on the locking block

around a guide for the connector (not shown) 74 is attached. The rack 80 is by means of a

to attach and hold and the connector in the other bolt 84 pivotable with the upper

to bring correct position for squeezing. io handle 22 connected. As in the following in more detail

Other details of the operation of the crimp will be described, the housing 82 takes a pawl 86

head itself are known and are not here on which cooperates with the rack 80 to

described in detail. ensure that the operator has to provide

In accordance with the present invention, the depth of a bruise can be in full depth the handles 22 and

with which the tips of the punch 34 bring the punch 34 together closely enough during the 15-24.

Crushing penetrate into the connector with the help of According to the present invention, the lower abuts

a knob 48 on the end of the handle 24 end of the rack 80 against the bolt 78, as in FIG

can be set. The handle 24 has a Fig.2 is shown to the movement of the

trough-shaped cross-section, as shown in FIG. 1 to hold handles 22 and 24 towards one another. Consequently

will provide. The end face of the handle 24 is provided with a 20 serving as a rack in the ratchet mechanism

End plate 50 provided on which the knob 48 76 both as a holding or stop device such as

is present As in F i g. 2 is shown, the knob is also called a rack. This arrangement is very

48 on the flattened end of a spindle 52 in advantageous, as described in more detail below

Can be moved longitudinally, which is longitudinally. '

device in the groove in the handle 24 extends. The 25 As shown in both the upper part of FIG. 1 as well

Rotary knob 48 has a shaped hole from FIG. 1 in its center. 2 is near the head of the

on, which is provided with the flattened end of the spindle 52 of the tool 20, a transparent window 88

fits together The end of the spindle 52 is slidable in hen. Markings 90 are provided on the window,

the hole in the collar 54, which indicates the depth of the pinch. As in Fig. 2

Rotary knob 48 is operatively connected to the spindle 52. 30 is a marker 92 on a plate

The rotary knob 48 is fastened with an axial recess 94, which is secured with the aid of a screw 96

provided, in which a compression spring 56 is fitted, adjustable on the left part of the locking block 74

which bears against a collar 58 attached to the end of the.

Spindle 52 is attached. The spring 56 pushes the A stop 100 is attached to the handle 24 and

Knob 48 and collar 58 away from each other and 35 has an adjustable stop screw 102. Of the

thereby presses the rotary knob 48 on the end plate 50 left part 95 of the locking block 74 is with one after

to. provided above approach 98, which is attached to the

As shown in FIG. 1 shows the rotary knob 48 with the left end of the screw 102 abutting to the movement

a number of slots 60 leading around the locking block 74 to the adjustable knob

its inner circumference are arranged. Limit the end of 40 to 48 out. The protruding part of the

Handle 24 has a projection 62 which is used in locking block in which the screw 96 sits

one of the slots 60 engages to the rotary knob 48 in the same way, the movement of the locking block

to hold against unwanted twisting. To limit the length of kes 74 in the opposite direction,

of projection 62 is dimensioned so that when the screw 102 is adjustable to the limits of the

Rotary knob 48 against the compressive force of the spring 56 45 to determine the movement of the locking block. A

is pulled outward, the projection 62 from the roll neck 104 prevents the locking block 74 itself

Slots 60 emerges and the knob 48 to move upwards.

Adjusting the crimping tool can be rotated freely. The adjustment mechanism of the tool 20 is working

can. The rotary knob 48 has a bore 63 as follows: The spindle 52 rotates when the knob 48

(see Fig. 2), and the flat end of the spindle 52 is rotated at 50. Since the locking block 74 is not

a bore 65 which can rotate with the bore 63 moves the rotation of the spindle 52

is aligned when the knob 48 is in his and the threaded portion 72 the locking block and his

closest position to the plate 50 is located. When the pivot pin 78 is longitudinally in the handle

Rotary knob occupies this latter position, a 24. Since the rack 80 with respect to the longitudinal axis

Piece of wire inserted through the bores is inclined to 55 of the spindle 52 and the locking block 74 and

to block the knob in this position and one because the rack abuts against the bolt 78 and as

Changing the setting of the tool to the stop is used, changes the longitudinal movement of the

impede. Locking block the possible movement of the handles

As shown in FIG. 2, the spindle 52 is moved towards and away from one another and changed Using a bearing block 64 rotatable in the handle 60 thus the depth of the pinch. Since the rack 80,

24, with the bearing block by a pair which is used as a stop member

of rivets 70 worked thereon on the handle is part of the ratchet mechanism 76, is

is attached. The spindle 52 is by a pair of the distance between the position in which the end

Cuffs 66 and 68 suitably fastened thereon to the rack 80 butting against the bolt 78, and the and bump against the end faces of the block 64, at the 65 »release point of the ratchet mechanism 76

Prevented sliding in the longitudinal direction. always precisely controlled and is

The spindle 52 has moderately tight tolerances at its left end, as follows

Threaded part 72, which is discussed in more detail with the same thread.

When moving the block 74 position indicated by turning the knob 48. During this

Moving left or right, moving the pawl 86 moves up in the right

Indicator mark 92 under window 88 back and leg of V-slot 108 printed. The latch and

before, indicating the depth of penetration of the punches 34. the teeth 124 are dimensioned so that the pawl 86

With this device, the worker cannot move the depth 5 into the left leg of the slot 108

can be squeezed quite easily with great accuracy as long as it lies in one of the flat teeth 124,

to adjust. The provided micrometer-like adjustment. Thus, the rack 80 is free to move to the right

mechanism increases this accuracy. Move example, as the pawl 86 is free in the right leg

wise are on the circumference of the button 48 eight slots of the slot 108 can enter, but is against

60 provided. Turning the knob 48 by a movement to the left is blocked because the pawl 86 is against

The depth of the crimp by approximately 0.0127 mm is the lower tip 129 between the thighs of the slot

('/ 15 000inch). Of course, it is not necessary for the V-slot 108 to abut. In the one shown in Fig.4

dig, such slots in an "infinitely" adjustable position, it is not possible to put the handles together.

Tooling is provided, but it is preferred to squeeze it, whereas it is possible to squeeze it apart

do to be able to put the knob in a 15. This prevents a further squeezing effect,

To hold the position to which he is set. until the pinched connector out of the tool

Fig. 3 to 8 show additional construction and has been removed.

Functional Details of the Ratchet Mechanism- When the rack 80 moves into position

mus 76. The pawl receiving housing 82 has, as shown in FIG. 5 is shown in which the

a generally rectangular cross-sectional shape, 20 end face 128 of the rack behind the pawl 86

as in Fig. 8 is shown. It has moved with an increase, the pawl is free to move to the deepest

106 provided, in which two V-shaped slots 108 places of the slots 108 to move, as in Fig.5

are incorporated, of which in FIG. 3 to 6 is only shown. The handles are in this position

one appears. The slots are completely spread apart in opposite ones.

Side walls of the housing 82 incorporated. The 25 when the handles come together again into one

The pawl 86, which is of rectangular cross-section, can be moved to the position shown in FIG. 6 illustrative

extends between the slots 108. As in FIG. 8 is light, the pawl 86 has in the left leg

is shown, an inverted U-shape of the V-slot 108 is moved. Although she is free in that

Bracket 114 attached to the ends of pawl 86. A left thigh can move, it is through the

Pin 110 is at the elevation 106 of the housing 82 30 · lower tip 129 prevented from being in the right

attached and extends through a bore in the leg to move. Thus, the rack 80 is free,

Upper part of the bracket 114. A compression spring 112 tends to move to the left, but the

to do this, the top flange of the pin 110 and the movement to the right is blocked. Before the

Bracket 114 away from each other so that the handles of the tool are pulled apart

Pawl 86 pressed down on the rack 80 35 the can, they have to go all the way into one

is moved and with the teeth of the rack in engagement position in which the pawl in the deep

remain. Notch 126 falls.

The rack 80, which is shown in more detail in FIG. 7 in accordance with the present invention, is also one

is shown at its ends with in the center screw 130 with a point in a hole

arranged slots 132 and 134 provided via 40 that extend through the left face of the

Grooves in the handle 22 and the block 74 fit notch 126 extends. The screw 130 can be inserted into the

and has a number of relatively flat ones in FIG. 6 position shown are brought to a

Notches or teeth 124 . The slope of the other shallow indentation next to the deep indentation

Sides of the notches is approximately the same as the 126 to create and manufacturing tolerances and others

Slope of the sides of the V-shaped slot 108. At 45 sources to compensate for the inaccuracy of the tool.

right end of the shallow notches 124 is chen.

a relatively deep notch 126 (see Using Part of the Ratchet Mechanism)

Fig. 4). The inclination of the sides of this deep single core as a stop is a very beneficial feature

Exercise is also approximately the same as the inclination of the present invention. This arrangement sees the

the sides of the slots 108 and the deepest point of the 5 ° precise control of the "pawl release point"

Notch 126 is approximately at the same level as before, that is, the point at which the pawl 86 in the

the deepest points of the slots 108. The deepest points deep notch 126 falls. It also controls exactly that

of the flat teeth 124 are substantially above the position in which the surface 127 of the rack is in contact

the deepest points of the slots 108. the bolt 78 abuts. This combination allows

As the mechanism in FIG. 3, 55 are particularly precise control of the crimping tool handles together and the crimping depth provided by the tool. In addition, the the mechanism 76 adopts the one shown in FIG. The mechanism shown in FIG. 2 is simple and does not move easily.
Position. Thus, the left part 127 of the ratchet rack 80 shown in the drawings abuts against the bolt 78 and prevents the mechanism in and of itself has many advantages. He handles it to move even further towards each other is simple and easy to assemble and to become easy. The pawl 86 lies on the lowest points of the set. It ensures positive guidance of the slots 108 and the bottom of the large notch rack 80 in the housing 82, so that few errors 126. in the setting of the stop and the switching pawl

The crimping tool 20 has four springs, a ken release occur. Furthermore, the pawl bends

on each cam follower 32, the handles 22 ⁶ 5 part 86 soft very little when loaded. Because the distance

and press 24 apart. If the operator is right between the tip 129 and one of the teeth 124

Releases handles, spread them apart and is small, there is no great bending length of the

the rack 80 begins to the right in the in FIG. 4 latch. The robustness of the latch part 86 and his

Housings ensure that the latch mechanism will be relatively trouble-free.

The squeezing tool illustrated in FIGS. 9 to 12 140 is a tool that can be adjusted "in steps"; i.e., a tool in which the crimp depth is only in special predetermined levels or increases can be set. One such tool will be preferred over the "infinitely adjustable" tool described above, as the provision is more predetermined Setting levels of errors kept to a minimum when executing the instructions workers using the tool arise.

Many of the components of the one shown in Fig.9 Tool 140 are identical to those of the tool 20 shown in the previous figures and for the same reference numerals are used for corresponding parts. The construction of the head part 25 of the The tool is identical to that of the one in FIG. 1 and 2 shown tool 20 and is in F i g. 9 not shown to avoid unnecessary repetition.

The adjustment knob 48 'is operatively connected to a relatively short spindle 142, which is a soft one has hexagonal shaped right end portion or head 144. The button 48 'is hexagonal with a like formed recess in which the head 144 slides. A removable bracket 146 is with their Ends secured in bores in head 144 to permit movement of button 48 'with respect to head 144 to the outside limit and to lock the button in its position. As in the in Fig. 1 illustrated Embodiment of the invention, the spring 56 pushes the head 144 and button 48 'apart, so the Press button 48 'on plate 50. A collar 148 is on the inside of plate 50 on spindle 142 mounted to rotatably attach the knob structure to the end plate.

In contrast to the one shown in FIG. The embodiment illustrated in FIGS. 1 and 2 is the button 48 'in its left Only provide the surface with a slot. A single protrusion 147 is mounted on plate 50. Consequently can only by turning the knob one or more full turns of the projection 147 with the single slot in the button. The mechanism, which in the following ensures that the crimp depth for each revolution of the knob 48 'is within a range of predetermined size is set.

As shown in Figures 9 and 10, the left one is End of the spindle 142 machined in half in the longitudinal direction and provided with a flat surface. The flattened end of the spindle 142 fits into the cylindrical bore in the center of the bearing block 64 and is effective with the right end part, which is machined flat in the same way, of another spindle 152 connected, which has a threaded portion 154 on its left side. The flat part on the right The end of the spindle 152 has a protruding shoulder 150 (see FIG. 10), which is used for purposes that are in the to be described below, abuts the right edge of the bearing block 64. Spindles 142 and 152 are thus displaceable in the longitudinal direction with respect to one another and yet are inevitably linked to one another coupled so that they can both be rotated with the aid of button 48 '.

The left threaded portion 154 of the spindle 152 fits into an eccentrically arranged threaded hole in the right end of a block 158 of circular cross-section. The block 158 fits under a spring 160, which holds the part down and yet allows it to move lengthways. A compression spring 156 is is attached between the left edge of block 64 and the right edge of block 158 and pushes blocks 64 and 158 away from each other. A stepped stop 162 is provided with the aid of a bolt 164 pivotally connected to the block 158, the bolt 164 in the block 158 in a hook-shaped Part 163 at the right end of the stop 162 fits the

ίο Stop 162 has an inclined slot 165 in the lower edge of which has a series of steps or notches 166 machined into it. The bolt 78 of the The ratchet mechanism 76 rests on one of the notches 166 determined by the position of the stop 162 depends. Fig. 12 shows the front wall of the handle 24 when the handles 22 and 24 be moved towards and away from each other. When the bolt 78 is at the bottom of the elongated hole 168 sew, it comes to rest on one of the steps 166 and against the rear wall 169 of the elongated hole 168. Since the Rack 80 abuts the bolt 78, the movement of the handles towards each other at one point stopped, which depends on the step or notch 166 in which the bolt 78 is held.

The left end 178 of the stop 162 extends under the central portion of a shouldered guide roller 180. A marker 92 is attached to part 178 which moves under window 88 to as in FIG. 1 and 2 illustrated embodiment of the invention to indicate the depth of the pinch.

The tool 140 operates as follows: Turning the knob 48 'through one revolution causes the Screw 154 to move block 158 right or left a distance equal to the width of one of the Steps 166 on the part 162 corresponds, whereby the stop point of the bolt 78 increases or decreases and the crimping depth of the tool is increased or decreased by one step.

Occasionally a worker twists the knob 48 '

■ 40 not by one complete revolution and deletes that Mechanism in a position as shown in FIG. 11 is shown where the bolt 78 is at the tip of a attacking teeth forming steps 166 rather than on one of the steps themselves. This condition is right undesirable because it could damage the tool and because the squeezing depth of the tool does not increase one of the desired amounts is set. According to the present invention, this state becomes corrected automatically. As in Fig. 9, the spring 156 normally holds the boss 150 against the right edge of the block 64. There is thus a clearance between the end faces of the spindles 152 and 142, which allows the spindles to slide toward each other a distance sufficient for that To allow bolt 78 to slide down a step and thus to lie on the next lower step come when the handles are squeezed together. The tool is thus automatically positioned itself one, which ensures that its crimp depth despite inaccurate adjustment to one of the predetermined level amounts is set.

Furthermore, the exact setting of the crimping depth is made by the mechanism shown in FIGS intended. A special stop 200 is on the

upper handle 22 of the tool 140 attached. The stop 200 is through a bolt 204 pivotally mounted on the web part 202 of the handle 22. The bolt 84 with which the rack

80 is connected, is fastened in a web part 206 of the upper stop 200.

The angular position between the handle 22 and the pivot point 84 of the rack 80 can be adjusted with the aid of a screw 208 in a threaded hole 210 in the handle 22. As shown in FIG. 9, the upper end of the screw is provided with a slot into which a screwdriver can be inserted to turn the screw and adjust the angle between the handle 22 and the pivot point 84. The plastic coating 46 normally covers the bore since it is undesirable for the user of the tool to adjust the screw 208. Instead, this setting is carried out in the factory and then the plastic coating is applied over the bore in order to prevent unauthorized handling of the screw by the user of the tool.

As clearly shown in FIG. 13, the stop 200 has a curved part 212 with a rounded inner slot 214 and lugs 216 on its upper edges. The lower end 218 of the screw 208 is rounded and a compression spring 220 is attached between the flat portion of the rounded head 218 and a washer 222, the edges of which abut the tabs 216. The spring 220 urges the lower portion 218 and washer 222 apart. Thus, the lower part 218 of the screw 208 is always pressed against the curved bottom of the rounded slot in the part 212 of the stop 200 when the handles 22 and 24 are pressed together and the screw 208 holds the handle 22 at a certain angular setting with respect to the pivot pin 84 The screw 208 can be used to adjust the tool in the factory to compensate for manufacturing tolerances and the like and to provide extremely precise control of the crimp depth of the tool. Further adjustments can be made using the auxiliary tooth 130 in the ratchet mechanism 76, as described above.

For this purpose 3 sheets of drawings

Claims (12)

Patent claims: 1. Clamping pliers for electrical connection parts with several shaped elements, a pliers-like Pair of handles, a first stop member on one of the handles, a second stop member on the second handle, a support member attached to one of the stop members and in Engagement with the other of the stop members is movable to support the handles and to prevent their further closing after moving to a predetermined shutter distance have been closed, characterized by a screw adjustment in a handle (24), with which the first stop member (78, 162) can be adjusted in the longitudinal direction in the first handle, to change the closing distance, and the interlocking threaded parts (72,154; 74,158) contains, of which one (74, 158) with the first stop member (78,162) and the other (72,154) with is coupled to the first handle (24). 2. Clamping pliers according to claim 1, characterized in that the stop members (74,84) so are attached that the support member (80) is inclined with respect to the first handle (24) when the Handles are in a closed position, the first stop member (162) has a surface that with respect to the first handle in a sense opposite to the inclination of the support member is inclined. 3. Clamping pliers according to claim 2, characterized in that the inclined surface is a row of slots (166) into which an end face (78) of the support member (80) fits. 4. Clamping pliers according to claim 2 or 3, characterized by a hand-operated handle (48 ') and a coupling arrangement (142, 150, 152) for making the longitudinally sliding and rotatable driving engagement between the handle and one of the male and female threaded members and a elastic arrangement (156) which engages the coupling arrangement to the first stop member (162) to press against the support member (78). 5. Clamping pliers according to claim 3, characterized by a hand-operated handle (48 ') in addition to one End face of the first handle (24) is provided which actuates the screw setting arrangement, wherein the handle has a locking mechanism (147) to prevent the handle from rotating after one revolution to lock and an arrangement for guiding an end face (78) of the support member against the first * Stop link (162) in a preselected position, the pitch of the threads of the screw assembly (154) being such that around the first stop member (162) to move a slot in position for each revolution of the handle. 6. Clamping pliers according to claim 1, characterized by a handle (48) next to an end face of the first handle (24) and longitudinally slidable with the other (72 ') of the male and female threaded members connected, a locking member (62) on the handle, a number of circumferentially spaced from one another arranged locking notches (60) in the handle and an elastic arrangement (56), the The handle is biased onto the locking member (62). 7. Clamping pliers according to one of the preceding claims, characterized by an adjustable one Arrangement to the second handle (22) with respect to the second stop member (84) angularly to adjust the maximum depth of the notch made by the tools (34). 8. Clamping pliers according to one of the preceding claims, characterized by a window (88) in the first handle, notch depth markings (90) next to the window, a mark (92) in the window next to the depth marker, with the marker attached to the first stop member for movement is coupled with it. 9. Clamping pliers according to one of the preceding claims, characterized in that the support member (80) includes the rack member of the ratchet assembly positioned between the handles connected to prevent movement of the handles away from each other until they come onto one have moved a predetermined position relative to each other, the pawl assembly, the pawl member (80) which is attached by a stop member (84) to one of the handles (22) and a Arrangement (76) for guiding the rack member into engagement with the other stop member (78, 162). 10. Clamping pliers according to claim 9, characterized in that the rack member (80) has a Has a series of relatively shallow slots (124) each having a first depth and having a relatively deeper slot (126) and the pawl assembly includes a pawl (86) which is slidably mounted in and engaged with at least one slot (108) in the guide assembly the slots on the rack is biased, the slot has two oppositely inclined sections and a lower part is attached next to the bottoms of the shallow slots to hold the latch in to hold one of the sections of the slot while engaging one of the shallow slots and the pawl is free to occupy each slot section when engaged the deeper slot. 11. Clamping pliers according to claim 10, characterized characterized in that the rack member (80) has an extendable member (130) which is in a inclined surface of its deeper slot (126) is recessed, the latter member outwardly from the surface is extendable to another of the narrow slots next to the deeper slot form. 12. Clamping pliers according to claim 10 or 11, characterized in that the guide arrangement has two V-shaped slots (108), wherein the tip (129) shows the V in the direction of the rack member (80) which is in the guide assembly (82) fits and slides therein with the guide assembly having a pair of opposing Has side walls, each with one of the slots therein and in which the pawl is located extends between the slots with an end face in each slot, a bracket (114) with the End faces of the pawl is connected and an elastic member (112) the bracket in the direction of the Pretensioned guide arrangement.