EP0586342B1 - Method for driving several rods, particularly for manual dispensing devices - Google Patents

Description

The present invention relates to a method for advancing two or more bars according to the preamble of claim 1 and a device for carrying out the method, in particular for use in a manual discharge device for two-component materials. Such a device is known for example from DE-A-3 128 611. In it, the push rods can be actuated by a clamping jaw and a bracket by a hand lever, and a counter bearing is provided for lateral support of the push rods, on which the clamping jaws are pivotally mounted and the feed drive contains a relatively complex slide.

EP-A-408 494 discloses a hand-held device in which bending and tilting of the push rods is effectively prevented by the feed drive acting on a push element which acts on the push rods essentially only in the direction of the push rods, but the force is transmitted via racks.

Based on the prior art mentioned, it is an object of the present invention to provide a method in which the feed drive is effective even with high forces and without a dead path, and thus a perfect power transmission is ensured. In particular, when used for double discharge cartridges with different diameters, in which different reaction forces occur on the push rods, the aim is to prevent the push rods from being displaced relative to one another so that the volumetric mixing ratios do not change. This object is achieved with the method as defined in the claims. The other claims contain devices for performing the method.

Accordingly, the feed rods are guided in a slide which can be moved in the direction of the feed of the squeezing pistons and which contains two clamping levers which are held only loosely in the slide. The clamping levers each have a bushing for one of the feed rods. When the carriage moves forward, i. H. in the discharge direction, the clamping levers are driven offset to this feedthrough, resulting in a torque which leads to a tilting of the clamping levers on the feed rods in the area of the feedthrough. When the carriage moves forward, the clamping levers can no longer turn, are carried along and thus transmit the forward movement to the clamped push rods. Since the path of the drive of the clamping levers occurs as a dead path to the outside as far as the clamping is reached, suitable measures, such as fitting the clamping lever bushings for the feed rods, hard surfaces, etc., must ensure that this path is small. Differences in the dead travel of the clamping levers are rendered ineffective by exposing the clamping levers to a small, permanent clamping force, e.g. B. by pressure springs.

According to the invention, the bending moment on the push rods which occurs during the clamping is almost completely absorbed in the slide, ie the guide of the slide is not loaded by the clamping alone. This is achieved in that the push rods run in the slide in tightly fitted and possibly lubricated guides, and in that the bending moments which generate torques in the slide via these guides are aligned in opposite directions. The additional friction generated by the bending of the feed rod does not make the forward movement more difficult, but rather an even firmer mechanical one Contact between slide and feed rod. In this context, it is advantageous to arrange the feed rod guides as close as possible in the slide to the clamping levers.

The slide guide only has to absorb the difference between the forces acting on the pistons and transfer them to the housing. This difference disappears for cartridges with a mixing ratio of 1: 1.

As a slide guide, it can be sufficient to guide only the push rods in the housing, for example when entering and exiting the latter. It is often advisable to provide separate guides for the sled. The more precisely this guide works, the less the slide can jam under the different piston pressures, and the deviations in the mixing ratio that would result from this are minimized. The slide guide can also be better adapted to the stresses that occur, as a result of which the frictional forces that occur are reduced compared to a guide via the push rods.

For smooth operation and long durability, the push rods, the passage openings of the clamping levers and possibly also the guides of the push rods in the slide have a hard and smooth surface. The high clamping forces nevertheless ensure that the push rods are carried safely. Smooth surfaces allow the push rods to be pulled back with less effort despite the relatively large number of guides.

With the propulsion device according to the invention, further devices, some of which are known and advantageous in practice, can be easily combined. Examples of this are the backstop (s), unlocking the backstop (s) and Locking of the clamping levers to allow the push rods to be pulled back.

Figur 1

zeigt einen Schnitt durch ein Ausführungsbeispiel der Erfindung,

Figur 2

zeigt einen Schnitt des Gerätes von Figur 1 gemäss der Linie II - II,

Figur 3

zeigt einen Schnitt des Gerätes von Figur 1 gemäss der Linie III - III,

Figur 4

zeigt eine Aufsicht auf den Schieber 48,

Figur 5

zeigt eine Auschnittsvergrösserung des Gerätes von Figur 1,

Figur 6

zeigt einen vereinfachten Schnitt gemäss der Linie V - V in Figur 1, und

Figur 7

zeigt einen Schnitt eines weiteren Ausführungsbeispiels der Erfindung.

The invention will be further explained using an exemplary embodiment.

Figure 1

shows a section through an embodiment of the invention,

Figure 2

shows a section of the device of Figure 1 along the line II - II,

Figure 3

shows a section of the device of Figure 1 along the line III - III,

Figure 4

shows a plan view of the slide 48,

Figure 5

shows an enlarged detail of the device of Figure 1,

Figure 6

shows a simplified section along the line V - V in Figure 1, and

Figure 7

shows a section of a further embodiment of the invention.

Figure 1 shows a first embodiment of a hand-held device according to the invention with a housing 21, a handle 2, a trigger 3, and the double cartridge 4 with the two cylinders 5 and 6, which are only partially drawn, as known. The two components of the double cartridge are mixed in an upstream static mixer during the discharge process, whereupon they react chemically and harden or solidify. The two components should be removed from the cylinders by simultaneously pressing in each cylinder arranged squeeze pistons take place, whereby the masses are squeezed through the end opening (not shown) of the static mixer. The double cartridge 4 is not actually the subject of the present invention and has been described in detail, for example, in EP-A-294 672 by the same applicant. However, the hand-held device according to the invention is not limited to the operation of such double cartridges, but is particularly suitable for this.

Since the masses to be discharged can be quite viscous, relatively high forces have to be used to discharge them. On the other hand, it is desirable to dose as precisely as possible while precisely observing the mixing ratio of the masses to be discharged, so that overall high demands are placed on the mechanical components of such a device, because on the one hand the propulsion must be smooth and not jammed even with large forces and on the other hand it must be precise, so that no relative displacement of the push rods can occur. The ejection pistons 110 located in the cartridges are actuated by the tappet plates 7 at the ends of the push rods 8. These push rods are driven by the trigger 3 via a lever mechanism.

The trigger lever 3, which is fastened to an axis of rotation 9, is connected via the bearing pin 10 to a first pull tab 11 of a pull lever 13, which is connected to the pull tab 11 via a bearing pin 14 and is rotatably held in the bearing block 16 via a fixed axis of rotation 15. The sections of FIGS. 2 and 3 show that the pull lever 13 consists of two legs 100 and 101 which are connected by the axes 14 and 15 (FIG. 5). The projection 27 on the carriage 26 has a bore 32. The tension lever parts 100 and 101 are each provided with a long bore 28. A flattened on both sides runs through the bores 28 and the bore 32 Bolt 103, the component of movement of which is received transversely to the direction of advance of the slide 26 through the long bores 28, and which is rotatable in the bore 32. The spring 29 causes the entire feed device to be returned to the illustrated starting position when the trigger 3 is released.

The carriage guide can be designed as shown in FIG. 6. Devices 111, in which inserts 112 are inserted, are present in the housing 21 of the discharge device. Corresponding devices 113 of the slide 26 slide in the inserts 112. In the present example, the devices 111 with the inserts 112 and the devices 113 form a tongue and groove sliding system. The inserts 112 serve to increase the service life and improve the mechanical properties, such as reduced friction and more precise guidance.

The clamping levers 30 and 31 are held in the slide 26. As particularly shown in FIG. 5, these each have a bore 43, 44 through which a feed rod 8 passes. The bore 43 or 44 is partially towards the front, ie towards the cartridge 4, with a larger cross section. In the resulting gap between the feed rod 8 and the bore wall, the compression spring 34 or 39 is inserted, which is supported and guided by the bore wall in the carriage 26. Near the other end of the clamping levers 30 and 31, the compression springs 35 and 38 are inserted in a second bore, which press the clamping lever against the opposite pins 41 and 42 with a cambered surface and are also supported on the carriage 26 to the front. The bore 43 and 44 may be lined with a material in the area where the feed rod 8 is clamped, for. B. in the form of a socket, which guarantees a long life with good clamping effect.

In the carriage 26, the release pins 46 and 47 are slidably guided in the feed direction and interact with the release slide 48 resting on the back of the hand-held device. The release rod 50, which can be pivoted laterally around the shaft 52 according to FIG. 3, runs under the release slide 48.

In the front part of the housing 21 are in the space between the support plate 18, which is connected to the cartridge holder 104, and the cover plate 58, the locking levers 53, 54. They are set by the springs 74, 75 against the feed rods 8 running through holes in them . Tongues 55, 56 of the locking levers 53, 54 extend into recesses in the shaft 52.

The feed rods 8 are connected at the rear end by a bridge 17. The bridge 17 serves on the one hand from a safety point of view to terminate the feed rods 8 to the rear, prevents a permanent displacement of the feed rods 8 against one another and serves, e.g. when changing the cartridge 4, as a handle for pulling back the feed rods 8.

If the trigger 3 is moved in the direction of the handle 2, the tab 11 and, via the lever 13, the slide 26 is also pulled forward. First, the pins 41 and 42 press eccentrically to the bore 43 and 44 from the rear against the clamping levers 30 and 31. Since in the idle state these always rest against the pins 41 and 42 on the one hand because of the springs 35 and 38, on the other hand the springs 34 and 39 are slightly pretensioned with regard to the clamping of the feed rods 8, a clamp connection between the slide 26 and feed rods 8 is hereby built up without play and evenly by both clamping levers 30 and 31 during the feed. The clamping levers 30, 31 move around the Edges 105 and 106, respectively. The further forward movement of the slide 26 is then converted into an equal forward movement of the feed rods 8, the tappet plates 7 and finally the squeeze-out piston 110 in the cartridge cylinders 5 and 6, respectively. The uniformity of the clamping, and thus ultimately the same advance of the squeezing pistons, is particularly important in multi-component discharge systems for maintaining a constant mixing ratio. The construction according to the invention also compensates for different manufacturing play and signs of wear in the clamping elements.

If sufficient mass has been pressed out of the cartridge 4, the trigger 3 is released and the entire feed device automatically returns to the rest position under the action of the spring 29. Since the clamping is released by the clamping levers 30 and 31 during the return movement of the slide 26, the feed rods 8 are not necessarily taken along by this return. The clamping levers 30, 31 lie against the wall 108 or 109 of the slide 26 lying in front of them, thereby preventing jamming during the backward movement of the push rods 8.

The residual friction that still exists between the clamping levers 30, 31 and the feed rods 8 when the carriage 26 runs backward can, in connection with a residual pressure of the cartridge content, lead to a backward entrainment of the feed rods 8. This is prevented by a friction brake 65 which is known per se, e.g. B. from the European patent application EP-A-0,408,494 of the applicant, consisting of a slide with a certain friction on one of the feed rods 8 slider 65, the movement of which is limited by a stop 66 relative to the housing 21. Because of a small free path length corresponding to a short retraction of the feed rods 8, running can occur of discharge mass can be prevented. The friction brake, as shown, only needs to be present on one side, since the stability of the bridge 17 is sufficient to distribute the braking force over both feed rods 8.

In the case of more viscous discharge masses which are pressed out under relatively high pressure, such a simple return brake is no longer sufficient, since the cartridge body no longer deforms negligibly elastically under the necessary high discharge pressure. At the beginning of the squeezing, the associated increase in volume must first be managed before it is discharged essentially in accordance with the plunger feed. This initial dead travel would occur again and again if the feed rods 8 could run back as desired when the trigger 3 was released. If the discharge device is also to be used for higher-viscosity discharge media, a device which prevents the feed rods 8 from moving backward is therefore very desirable.

This task is performed by the locking levers 53 and 54, which are shown in another view in FIGS. 2 and 3. During the feed they rest on the plate 58, so that the feed rods 8 can slide through the corresponding bores in the locking levers 53, 54 without being braked. If, on the other hand, the forward movement ceases, the locking levers 53 and 54 are pressed backward by the pressure springs 74 and 75, respectively, by rotation about the edge 70. Analogous to the clamping levers 30, 31, any play of the feed rods 8 in the bores of the locking levers 53, 54 is thereby rendered ineffective, and thus both feed rods are locked as precisely as possible at the same time. The smallest backward movement of the feed rods 8 then immediately causes the locking levers 53, 54 to jam due to the offset retaining force of the edge 70, which results in a further Backward movement of the feed rods 8 is safely avoided.

To change the cartridge, it is necessary to create a possibility for retracting the feed rods 8. This must not only bring the locking levers 53, 54, but also the clamping levers 30 and 31 into a freewheeling position. For this purpose, the release rod 50 is pivoted out of the position shown in FIG. 3. First, the slider 48 is moved upward by sliding the bevel 49 (see FIG. 4) over the release rod 50, as a result of which the pins 46 and 47 (see FIG. 5) are pushed forward over the bevels 107 of the slider 48 and so that the clamping levers 30 and 31 press into the freewheel position. Since the locking levers 53, 54 still absorb the backward pressure, only little force is required for this. Only when the release rod 50 is pivoted further are the tongues 55, 56 of the locking levers 53 and 54 gripped by the edge 77 and 78 of the shaft 52 rotated with the release rod 50 and pressed forward against the plate 74 into the freewheeling position, after which the feed rods 8 with the pusher plates 7 can be retracted by pulling on the bridge 17.

The danger that the clamping levers 30, 31 also jam when the feed rods 8 are manually pushed forward quickly has been countered by the fact that the clamping levers 30, 31 strike the wall of the carriage 26 in front of them before a forward-acting clamping occurs.

Depending on the application, both of the two backstops specified in the exemplary embodiment may be present or one may be omitted, ie only the friction brake or only the locking lever brake can be present. The friction brake could also be used several times, especially for everyone Feed rods are available. It could then consist of several friction bodies or a single larger one, which grips the feed rods. The friction brake could also be attached to the housing of the discharge device without play in order to prevent any free return. Instead of the two locking levers described, there can also be only one locking lever, in which case the locking action is transferred from the bridge 17 to the other feed rod (s) not captured by the locking lever.

A further position of the release rod could be provided, in which the locking levers 53, 54 are pressed into the freewheel position, but the clamping levers 30, 31 are released, i. H. the slider 48 is not pushed up. In this position, only the friction backstop is effective, as a result of which the discharge device can be quickly switched from the discharge of highly viscous to the discharge of low-viscosity masses.

An alternative would be locking devices such as Clamping screws that push the locking levers 53, 54 into the freewheel position.

The exemplary embodiment according to FIG. 7 has some simplifications. The handle 2 with the trigger 3 and the double cartridge with the two cylinders 5 and 6 are the same as in the previous example. The same applies to the other components 7-11. Similar to the preceding examples, the pull tab 11 acts via the bearing pin 120 on the pull lever 121, which is rotatably held in the housing via a fixed axis of rotation 122 and is connected to the slide 125 via a bolt 124 sliding in the elongated hole 123. In addition to the bore for axis 122, a second bore is provided in the housing in order to achieve the gear ratio to be able to change. The slide guide is designed similar to that illustrated in FIG. 6.

In a departure from the preceding explanations, the two clamping levers 126 and 127 are arranged in the slide 125 at the same height, but obliquely relative to one another with respect to the plane of the push rod, that is to say, the clamping lever 126 points to the rear in the arrangement in FIG. 7. The actuation and action of the clamping levers via pins 41 with a cambered surface and the bore 43 with compression spring 34 is the same as in the previous examples, but tension springs 128 fastened to the slide act on the ends of the clamping levers on the push rod side instead of compression springs 35. The friction brake 129 is similar in effect and structure to the friction brake 65.

The exemplary embodiment according to FIG. 7 has above all a more effective unlocking of the backstop containing the locking levers 53 and 54 and the clamping lever. This unlocking mechanism, which is effective for changing cartridges or relieving cartridges against reflowing, contains a first unlocking rocker 130 acting on the clamping levers and a second unlocking rocker 132 acting on the locking levers. The first rocker is connected to the second rocker approximately in the middle via a guided rod 133. An unlocking lever 134, which is mounted about axis 135 and has a high transmission ratio, engages on the first rocker 130. A return spring 136 is connected to the release lever. For the purpose of tolerance compensation, the first rocker 130 has two adjustable threaded bolts 137 which, when the unlocking lever 134 is actuated, act on pressure pins 131 in the slide, and these in turn act on the clamping levers in order to bring them straight, ie into the inactive position. In order to keep the rockers under pretension, the second rocker 132 has a compression spring 138 which is supported on the housing.

When the unlocking lever is actuated, the first rocker 130 acts on the one hand via the threaded bolts 137 on the pressure pins 131 in the slide and these on the outer ends of the clamping levers, and on the other hand via the rod 133 directly on the second rocker 132, which acts on the locking levers, as a result of which both Clamping levers as well as the locking levers can be unlocked to enable the push rods to be pulled freely or the cartridges to be relieved.

If the push rods do not have the same diameter, the stronger push rod is firmly guided, while the other push rod is guided with slight play. In one embodiment variant, the bridge 139 is produced from two shaped pieces which grasp the push rods 8 axially without any play and radially with some play and are screwed together.

Conventional lightweight materials, preferably plastics or light metals, can be used as the material for the housing of the discharge device and for almost all internal parts. The more heavily loaded parts, such as the lever 13 and its mounting in the housing, the pins 41 and 42 etc. can be made of metal, for example. The bearings and also the through bores in the clamping and locking levers 30, 31 or 53, 54 and the slide 26 can be equipped with metal bushings, wherein the feed rods can be made of correspondingly hard or surface-hardened material to avoid indentations. The inside of the guides and the surface of the feed rods can be smoothed or polished to allow the rods to slide easily in the guides. The large clamping forces still ensure sufficient driving force.

Claims (16)

1. Method for the uniform advance of at least one thrust rod (8) against a feeding resistance in a dispensing appliance having a slide (26, 125), characterised in that each thrust rod (8) is guided in bores of said slide (26, 125) and passes through a bore (43, 44) of one of the clamping levers (30, 31; 126, 127) which are movably mounted in said slide (26, 125), said clamping levers being tilted, when said slide (26, 125) is advanced, with respect to the thrust rods (8) passing therethrough around an axis which is perpendicular to said thrust rods (8), whereby said thrust rods (8) are clamped in said bores (43, 44), the bending moment thereby imparted to said thrust rods (8) being received by the guidings of said thust rods (8) in said slide (26, 125), and the torsional moments resulting from the clamping action in said slide (26, 125) cancelling each other when the feeding resistances of said thrust rods (8) are equal.
2. Dispensing appliance implementing the method according to claim 1, for multicomponent substances which are contained in cartridges, and for manual operation, comprising a slide (26, 125) which is displaceable forwards and backwards with respect to the dispensing direction, characterised in that clamping levers (30, 31; 126, 127) are movably mounted in said slide (26, 125), through a bore (43, 44) of which a respective thrust rod (8) passes, and in that at least one respective thrust means (41, 42) which is disposed eccentrically with respect to said bore (43, 44) and displaced along with said slide (26, 125), as well as further means (34, 39) are provided in order to simultaneously tilt said clamping levers (30, 31; 126, 127) with respect to the respective thrust rods (8) and to drive the latter forward under the effect of the thrust.
3. Dispensing appliance according to claim 2, characterised in that said further means are first spring elements (34, 39) serving the purpose of pretensioning said clamping levers (30, 31) with respect to said slide (26, 125) against the dispensing direction, so that said clamping action is free of play and simultaneous when said slide (26, 125) is advanced.
4. Dispensing appliance according to claim 2 or 3, characterised in that said clamping levers (126, 127), seen in the dispensing direction, are arranged at the same height and extend obliquely to each other with respect to the plane of said thrust rods.
5. Dispensing appliance according to any one of claims 2 to 4, characterised in that second spring elements (35, 38; 128) are provided in order to press one of said clamping levers (30, 31; 126, 127) against the corresponding one of said thrust means (41, 42) each.
6. Dispensing appliance according to any one of claims 2 to 5, characterised in that stop means (108, 109; 131) are provided in order to prevent, particularly during the direct advance of said thrust rods (8) through said clamping levers (30, 31; 126, 127), any tilting of said clamping levers (30, 31; 126, 127) in the dispensing direction and thus a blocking of the advance.
7. Dispensing appliance according to any one of claims 2 to 6, characterised in that said thrust means are embodied as projections projecting from the walls of said slide in the advancing direction, more particularly convex surfaces, and preferably as parts (40, 41) which are inserted in the walls and are preferably provided with a hardened thrust surface, or are hinges for said clamping levers (30, 31; 126, 127) which are mounted on said slide.
8. Dispensing appliance according to any one of claims 2 to 7, characterised in that said thrust rods (8) and/or at least a part of the inside of said bores (43, 44) in said clamping levers (30, 31; 126, 127) are of a hard material, more particularly of metal which is preferably hardened and/or polished.
9. Dispensing appliance according to any one of claims 2 to 8, characterised in that at least one of the following return stops for said thrust rods (8) is provided:

   - at least one friction brake (65, 129) acting upon at least one of said thrust rods (8), consisting of a body which is freely displaceable in the housing on a small distance and imparts a friction to said thrust rod (8), said small distance being limited by stop means (66) which are secured to the housing of the appliance and act upon said body;

   - at least one friction brake which is fixedly mounted in the housing of the dispensing appliance and is capable of exerting a frictional force to at least one of said thrust rods (8);

   - at least one spring-loaded locking lever, preferably one locking lever (53, 54) per thrust rod (8), said lever being provided with a bore through which a thrust rod (8) passes, and movably engaging in a recess of the housing (21) of the dispensing appliance at a location which is offset from said bore in order to tilt with said thrust rod (8) when the latter moves backwards and to block it, as well as a forward stop of said locking lever, in order to prevent a blocking of the forward movement of said thrust rod.
10. Dispensing appliance according to claim 9, comprising a return stop having two locking levers, characterised in that said locking levers (53, 54) are in contact with said thrust rods by spring elements (74, 75) which act upon them against the feeding direction, in order to provide a simultaneous clamping action preventing a return motion of said thrust rods (8).
11. Dispensing appliance according to claim 10, characterised in that detent means (50; 132-134) are provided which are capable of maintaining said locking levers (53, 54) in a position wherein said locking levers (53, 54) allow a return motion of said thrust rods (8).
12. Dispensing appliance according to claim 11, characterised in that said detent means comprise a second releasing rocker (132) which is actuated by a releasing lever (134) and acts upon said locking levers (53, 54).
13. Dispensing appliance according to claim 12, characterised in that said releasing lever (134) acts upon a first releasing rocker (130) which is operatively connected to said second releasing rocker (132) by a rod (133).
14. Dispensing appliance according to claim 13, characterised in that said first releasing rocker (130) is actuated by said releasing lever (134) and is both operatively connected to said clamping levers by adjustable threaded bolts (137) as well as by thrust bolts (131) which are guided in said slide (125), and connected to said connecting rod (133) which acts upon said second rocker (132).
15. Dispensing appliance according to any one of claims 2 to 13, characterised in that the two thrust rods (8) are connected by a bipartite bridge (139) which is formed of shaped injection-moulded components.
16. Application of the dispensing appliance according to any one of claims 2 to 15 for multicomponent cartridges of any volumetric ratio resp. cross-sectional area of the storage cylinders (5, 6), preferably from 1:1 to 1:10.

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