GB1578055A

GB1578055A - Crimping tool

Info

Publication number: GB1578055A
Application number: GB14088/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-04-05
Filing date: 1977-04-04
Publication date: 1980-10-29
Also published as: CH619567A5; FR2347799A1; ES457568A1; SE7703853L; NL7703669A; DE2614577B1; FR2347799B1; SE416504B; NL181536B; IT1084930B; DE2614577C2; NL181536C

Abstract

The crimping tool, which is equipped with pressing jaws that are closed and opened by a working piston driven by a pressure medium and capable of moving to and fro axially, via an interposed lever drive (38, 39), is used to produce solder-free, permanent electrical connections by pressing the cables, lines or litz wires with the respectively required connecting pieces. The tool is equipped with special safeguarding means (16-25) in order to rule out defective pressing due to incomplete closure of the pressing jaws. After initiation of the working stroke of the piston, said means prevent interruption of the stroke motion of the piston until complete closure of the pressing jaws. <IMAGE>

Description

(54) CRIMPING TOOL (71) I, REINER ROMMEL, a German citizen of 3570 Stadt Allendorf, Moldaustrasse 6, West Germany, do hereby declare the invention for which I pray that a Patent may be granted to me and the method by which it is to be performed to be particularly described in and by the following statement: The invention concerns a crimping tool e.g. for making solderless permanent electrical connections by crimping a cable, conductor or wire together with a component such as a plug, terminal, socket, or connectors. Such tools usually have simultaneously operating crimping dies, which are opened and closed by reciprocation of a piston which acts through a linkage between the piston and the dies.

During this cycle depending on the design of the tool, the dies may effect a pivotal movement like a pair of pincers or there may be a linear crimping die movement. The linkage between the piston and the crimping dies provides for high crimping pressure required for proper crimping. The operating piston can be driven in various ways, for example by compressed air, the entry of which to the working piston cylinder is controlled by means of a valve operated by an actuating lever.

Most known crimping tools, whatever drive unit is fitted to them, have the defect that the working piston drive can be interrupted before it has completed a full working stroke.

This can lead to defective crimping of the work-piece, so that the joint is no longer then in accordance with the relevent safety and quality specifications.

The present inventon provides a crimping tool comprising a pair of crimping dies mounted for relative movement between open and closed positions, a piston movable to effect said relative movement in the closing direction by means of transmission means between the piston and the dies, a hydraulic or pneumatic control valve for supplying fluid pressure to the tool to drive the piston in the closing direction, actuating means for actuating the valve, operable means on the actuating means and the piston, the cooperable means holding the actuating means in the actuating position during movement of the piston until the piston has completed its stroke and the crimping dies are in the closed position, and means for disengaging the operable means and returning the actuating means to a non-actuating position when the piston has completed said stroke.

Reference is now made to the accompanying drawings in which: Figure 1 is a longitudinal section through a crimping tool operated by compressed air, thc crimping dies of which effect a pivotal movement; Figure 2 is a section along line Il-il through Figure Iide view, party 1; Figure 3 is a side view, partly in section, of another embodiment of a crimping tool with a linear crimping die movement; Figure 4 is a longitudinal section through the unit shown in Figure 3 turned through 900; Figure 5 is a diagram to illusuate the crimping die drive system; Figure 6 is a sectional view of the front portion of the actuating lever in the engaged position; and Figure 7 is a sectional detail of the unit along line VII--VII of Figure 6.

Both of the embodiments described are similarly constructed, except in respect of the operation of the crimping jaws and reference is initially made to Figures 1 to 4.

The rear section of the complete tool is formed by a compressed air cylinder 1, in which piston 2 may slide axially, the piston being provided with a piston rod, 3, which is guided in a bearing 4. The piston rod carries a tapered, conically shaped front end 5.

At the rear end of cylinder 1 a connecdon 6 is provided. This connection 6 is attached to a valve casing 7 and a compressed air connection 8. Between bearing 4 and piston 2, a compression spring 9 is located which surrounds piston rod 3, which ensures that the piston returns to its end rear position when the compressed air is switched off or when the cylinder 1 is evacuated.

A frame, which will be described in detail later, is mounted on beanng4, and is surrounded by casing 12 and receives internally for the actuation of the tool head, a lever drive, which will also be described later.

The tool is switched on and off by means of an escapement operating lever 11, which is mounted on a pin 10 on cylinder cap 13. By means of this lever 11 an inlet and outlet valve provided inside cap 13, or in compressed air connection 8, is actuated, which gives the compressed air access to the cylinder or ventilates the cylinder.

Ventilation is effected via sound damping insert 14.

Lever 11 extends forward to the tool head and is bent inwards at about the middle and led through an opening 15 in casing 12. Inside casing 12, a guide 16 with a guide slot 17, running in the direction of operation of the piston, connects with lever 11. At its ends, slot 17 forms extensions which define on entry point 18 and an exit point 19 respectively (to be described later) for a thrust block 20, 21 located on the front end 5 of the piston rod. This thrust block consists of a pin 20, (Figure 6) which has a diameter corresponding to the width of slot 17 and is fitted with a head 21.

At the point of transition from slot 17 to entry point 18, or exit point 19, lead-in bevels 22 or 23 are formed, which co-operate with guide surfaces 24 and 25 on head 21 of the thrust block and promote the smooth sliding entry or withdrawal of the thrust block into guide slot 17. In addition guide 16 is guided on journal 26, which is provided on the frame, and compression springs 27 are provided which urge guide 16, with lever 11, into the non-operating position, i.e.

the switch-off position. The tool is switched on simply by pressing lever 11 against the effect of spring 27. However, to prevent the tool being switched unintentionally, if the crimping cycle has not been fully completed, i.e. if the piston has still not reached its end position, then the safety unit formed by guide 16 and thrust block 20, 21 is provided. As best apparent from Figure 6, if lever 11 is pressed downwards, then thrust block 20 with head 21 passes through entry point 18 on guide 17, so that head 21 is now located over guide 16. Since at the same time as lever 11 was pressed down, the compressed air feed was switched on, the piston 2 immediately begins its working stroke towards the tool head.

Thrust block 20, 21 enters guide slot 17, and head 21 is located on the top side of guide 16, so that return movement of lever 11 is prevented. Since the length of the guide slot 17 in guide 16 corresponds to the full length of the piston stroke, thrust block 20, 21 slides into the area of exit point 19. When the thrust block has reached this point, the conical front end 5 of the piston rod has forced the crimping dies into their crimping position. When lever 11 is released by the operator, springs 27 return the guide 16 to the initial position, so that the guide is released from the thrust block, the head 21 passing through the exit point 19. If the lever 11 is released before the thrust block 20, 21 has reached the exit point 19, then the head 21 prevents return of the lever 11 to its non-operating position.

The safety device just described can be used both with crimping tools having pivotal jaws as shown in Figure 1 or with those with a linear opening and closing movement as shown in Figures 3, 4 and 5.

In the case of the embodiment shown in Figure 1 a tool head 28 has crimping jaws or dies 29 which open and shut with a pivotal movement. The dies are carried by shanks 31 which are pivotally mounted on respective spigots 30 in tool head 28 and which extend towards the conical front end 5 of the piston rod. Each shank carries a roller 32 which cooperates with the front end 5.

Leaf springs 33 are fitted one at each side of the casing 12, each spring acting on a respective shank 31 to urge the dies 29 to the open position, i.e. with the rollers 32 urged into contact with each other. The shanks serve as transmission means and during the working stroke of the piston, conical front end 5 of the piston rod is urged between the rollers 32, so that the two shanks 31 are urged apart and dies 29 are pivotally urged towards each other, about the spigots 30, in a crimping operation.

In Figure 5 a crimping tool is shown the crimping dies of which open and shut with a linear movement. In this case, in a tool head 34, there are provided a fixed crimping die 35 and an axially movable crimping die 36. The movable die 36 is housed in a slide 37, which is slideably engaged in the frame of the device. The transmission means comprising a pair of toggle linkages connected to the slide 37. Each linkage comprises a first link 38 pivoted at 42 to a second link 39. Each first link is pivotally connected to the slide 37 about a pivot 40. Each second link is pivotally mounted on the frame at 41 and adjacent the pivotal connection 42, each first link has a cam-like surface for engagement with the conical front end 5 of the piston rod. The cam-like surfaces are urged together by spring means (not shown). Axial closing movement of crimping die 36 is brought about by the front end 5 engaging between the cam-like surfaces and urging the first links 38 apart.

This brings the links 38, 39 of each toggle linkage towards alignment with accompanying movement of movable die 36 towards the stationary die 35.

The drive principle illustrated in Figure 5 is used in the crimping tool shown in Figures 3 and 4. In this case springs 43 can be seen, which urge the links 38 towards each other.

The frame of the tool basically consists of four longitudinal bars 58 (Figures 1 and 2) which extend through apertures 57 in a pair of longitudinally spaced discs 50. The two discs 50 are connected together by spacers 51 and are mounted on a collar formed on piston rod bearing 4. These two discs form a cage, located on bearing 4 and carrying on its exterior the cylinder 1, which is secured by a snap ring 52. An end ring 53 connects cylinder 1 to casing 12. Inside the cage formed by annular discs 50, four grooves or milled recesses 54 are provided on the outside of bearing 4 and suitable milled recesses 55 are provided on the insides of the bars 58. Two key wedges 56 driven between the two discs 5C key the cage to the bars 58. The connection can be easily released at any time by knocking out the key wedges 56. Key wedges 56 can be secured in position by a bolt, stud or the like. The bars 58 are bent inwardly and mount the spigots 30 near their ends.

In both embodiments, the bars 58, 58' have bores or fittings 60 at their front ends for interchange of the tool head, which is held in place by securing bolts 61. Through the direct connection of piston bearing 4 via bars 58 or 58' to the tool head used, all the stresses which occur in the tool are absorbed by the bar 58, 58' alone.

A ring 62 (Figure 3) is provided, underneath the operating lever 11 on the cylinder 1. The ring 62 is provided with a projection 63 and is rotatably mounted, so that the projection can be located beneath the operating lever 11 to prevent its depression and, therefore, to prevent operation of the tool.

The bars, the annular discs which form the cage and other components, such as the links and levers, can be stampings or pressings, which simplifies and reduces the cost of manufacture.

WHAT I CLAIM IS:- 1. A crimping tool comprising a pair of crimping dies mounted for relative movement between open and closed positions, a piston movable to effect said relative movement in the closing direction by means of transmission means between the piston and the dies, a hydraulic or pneumatic control valve for supplying fluid pressure to the tool to drive the piston in the closing direction, actuating means for actuating the valve, co-operable means on the actuating means and the piston, the cooperable means holding the actuating means in the actuating position during movement of the piston until the piston has completed its stroke and the crimping dies are in the closed position, and means for disengaging the operable means and returning the actuating means to a non-actuating position when the piston has completed said stroke.

2. A crimping tool according to Claim 1, wherein the operable means comprises a guide slot on the actuating means and a headed member on the piston and engageable in the guide slot, the slot having an entry point at one end and an exit point at the opposite end permitting passage of the head through the slot during movement of the actuating means towards its actuating position and away from its actuating position, respectively.

3. A crimping tool according to Claim 2, wherein said means for returning the actuating means to a non-actuating position comprises spring means acting on the actuating means.

4. A crimping tool according to Claims 2 or 3, wherein the ends of the slot are bevelled to facilitate entry and exit of the headed member at said entry and exit points.

5. A crimping tool according to any preceding Claim, comprising spring means urging the piston to its starting position and urging the dies to the open position.

6. A crimping tool according to any preceding Claim, wherein the tool includes a frame which supports the dies and the transmission means, the frame comprising longitudinal bars mounted on a bearing, the piston being provided with a piston rod which engages in the bearing.

7. A crimping tool according to Claim 6, wherein the bars extend through a cage, which is mounted on the bearing and keyed thereto, a cylinder being mounted on the cage and held in position by a snap-ring, the piston being engaged in the cylinder.

8. A crimping tool according to Claim 7, wherein the cage comprises a pair of discs connected together by spacers.

9. A crimping tool according to Claim 6, 7 or 8 in which the bars are provided with holes or fittings for releasably mounting a tool head, the tool head including the dies.

10. A crimping tool according to any preceding Claim, wherein the transmission means comprises a pair of pivotally mounted shanks, each carrying one of the dies, spring means being provided urging the shanks together so as to urge the dies apart, the piston being provided with a tapered end engageable between the shanks to urge them apart, so as to effect closing of the dies.

11. A crimping tool according to any one of Claims 1 to 9, wherein one die is fixed and the other die is linearly movable relative thereto, the transmission means comprising a toggle linkage connected between a body of the tool and the movable die, the piston acting on the linkage between its ends to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figures 3 and 4. In this case springs 43 can be seen, which urge the links 38 towards each other. The frame of the tool basically consists of four longitudinal bars 58 (Figures 1 and 2) which extend through apertures 57 in a pair of longitudinally spaced discs 50. The two discs 50 are connected together by spacers 51 and are mounted on a collar formed on piston rod bearing 4. These two discs form a cage, located on bearing 4 and carrying on its exterior the cylinder 1, which is secured by a snap ring 52. An end ring 53 connects cylinder 1 to casing 12. Inside the cage formed by annular discs 50, four grooves or milled recesses 54 are provided on the outside of bearing 4 and suitable milled recesses 55 are provided on the insides of the bars 58. Two key wedges 56 driven between the two discs 5C key the cage to the bars 58. The connection can be easily released at any time by knocking out the key wedges 56. Key wedges 56 can be secured in position by a bolt, stud or the like. The bars 58 are bent inwardly and mount the spigots 30 near their ends. In both embodiments, the bars 58, 58' have bores or fittings 60 at their front ends for interchange of the tool head, which is held in place by securing bolts 61. Through the direct connection of piston bearing 4 via bars 58 or 58' to the tool head used, all the stresses which occur in the tool are absorbed by the bar 58, 58' alone. A ring 62 (Figure 3) is provided, underneath the operating lever 11 on the cylinder 1. The ring 62 is provided with a projection 63 and is rotatably mounted, so that the projection can be located beneath the operating lever 11 to prevent its depression and, therefore, to prevent operation of the tool. The bars, the annular discs which form the cage and other components, such as the links and levers, can be stampings or pressings, which simplifies and reduces the cost of manufacture. WHAT I CLAIM IS:-

1. A crimping tool comprising a pair of crimping dies mounted for relative movement between open and closed positions, a piston movable to effect said relative movement in the closing direction by means of transmission means between the piston and the dies, a hydraulic or pneumatic control valve for supplying fluid pressure to the tool to drive the piston in the closing direction, actuating means for actuating the valve, co-operable means on the actuating means and the piston, the cooperable means holding the actuating means in the actuating position during movement of the piston until the piston has completed its stroke and the crimping dies are in the closed position, and means for disengaging the operable means and returning the actuating means to a non-actuating position when the piston has completed said stroke.

urge the movable die towards the fixed die.

12. A crimping tool according to Claim 11, comprising a pair of said toggle linkages having cam surfaces spring-urged towards each other, the piston being provided with a tapered end, which engages between the cam surfaces so as to act on the linkages.

13. A crimping tool constructed substantially as herein described with reference to Figures 1, 2, 6 and 7 or to Figures 2 to 7 of the accompanying drawings.