PISTON ASSEMBLY FOR A CARTRIDGE EVICTORY

Description

Cartridge ejection deviceField of technology

[0001] The invention relates to a cartridge ejection device with a piston for a cartridge ejection device for ejecting a pasty mass from a cartridge having an inner wall, having a rear side acted upon by a pressure plate, a front side opposite thereto and a holding member which, in a holding position, binds the pressure plate to the rear side with a holding projection which engages an edge of the pressure plate.

[0002] US 4,678,107 describes a cartridge ejection device with a piston on which a cap sits, which engages behind a pressure plate of the piston with a radially inwardly directed edge.

[0003] CN 204523433 U describes a cartridge ejection device with a piston carrying a replaceable pressure plate.

[0004] EP 2116484 A1 also describes a cartridge ejection device with a piston carrying a removable pressure plate. State of the art

[0005] US 2014 / 0084022 A1 discloses a piston ejection device in which the piston is connected to a pull-hood by hooks connected to the push rod. The hooks extending from the piston engage slots in the hood.

[0006] US 3,162,337 discloses a cartridge ejection device in which a pressure plate is firmly connected to a pressure rod. The pressure rod engages in a rear cup-shaped recess of the piston and is connected to the piston there like a bayonet lock.

[0007] US 3,069,053 discloses a similar connection of a pressure plate with a piston.

[0008] EP 3 075 457 A1 describes a cartridge ejection device with a piston. The piston has a front side which points in the direction of a pasty mass to be ejected from a cartridge, wherein a second piston can be arranged in the cartridge and can be acted upon by the front side of the piston. The front side of the piston opposite the back is attached to a pressure plate which is connected to the end of a pressure rod. The pressure rod can be displaced linearly by means of a stepping gear by moving a drive lever back and forth in order to displace the piston in an ejection direction. The holding member for securing the pressure plate to the back of the piston is formed here by a U-shaped web with an L-shaped cross-section which overlaps the edge of the pressure plate with a locking flank. The pressure plate can be pushed laterally into an opening.If a release lever on the cartridge ejection device is moved to a release position, the push rod can be retracted. This push rod moves the piston inside the cartridge.

[0009] From DE 20 2010 013 511 U1, an interchangeable piston for a cartridge ejection device is already known, in which retaining tongues engage in a groove.

[0010] Cartridge presses are also described in US 3,069,053 and WO 96 / 08428. Summary of the invention

[0011] The invention is based on the object of further developing a generic cartridge ejection device in a manner that is advantageous in use.

[0012] The problem is solved by the invention defined in claim 1.

[0013] The piston ejection device according to the invention has a piston with at least one first retaining projection, which is attached to the piston so as to be deflectable in a direction away from the pressure plate. By displacing the retaining projection relative to the pressure plate, the retaining projection is brought into a release position in which the pressure plate can be separated from the piston in a direction away from the rear. In particular, it is provided that the retaining projection is attached to the piston so as to be elastically deflectable. For this purpose, the retaining projection is fastened to the piston via a spring bar. Two or more retaining projections can be provided, each of which is attached to the piston in particular so as to be elastically deflectable. Two retaining projections can be located opposite one another. In particular, it is provided that the pressure plate is connected at its center to a pressure rod which is linearly displaceable in order to press the pasty mass out of the cartridge.The push rod defines an axis. The two holding projections are arranged diametrically relative to the axis. In addition, a limiting projection can be provided, which forms a contact flank against which the edge of the pressure plate rests. The limiting projection can be formed by an arcuate limiting rib. The stop flank is arranged in particular on a limiting rib that runs on the circumferential contour line of the piston between two holding members. According to the invention, the holding members can only be displaced from the holding position to a release position when the piston is not located in a cartridge. For this purpose, the holding member is provided with a supporting flank. The supporting flank preferably points radially outwards and moves radially outwards when the holding member is displaced from the holding position to the release position.The support flank is at such a radial distance from the axis of the piston that the inner wall of the cartridge lies in the path of movement of the support flank when the latter is displaced towards the release position. The inner wall of the cartridge thus forms, together with the support flank, a locking mechanism with which the holding member is held in the holding position when the piston is in the cartridge. The support flank is thus arranged in such a way that, when the piston is inserted in the cartridge, it prevents any deflection, in particular any elastic deflection, of the holding member into the release position by striking or resting against the inner wall of the cartridge. For this purpose, the support flank can be formed by a support arm which is arranged at a free end of the spring web. The support arm projects radially outwards.At the free end of the spring arm there is also the retaining projection which, on its side facing the rear, forms the locking flank which, in the holding position, engages over the edge of the pressure plate. The supporting flank or the supporting arm forming the supporting flank can be spaced a greater axial distance from the rear than the retaining projection. A side of the spring bar facing away from the edge of the pressure plate can be spaced radially from the inner wall of the cartridge. This radial distance is bridged by the supporting arm. The front side of the piston is formed by a pressure section which has a truncated cone-shaped outer wall. The front side has a radially outer edge whose radial distance approximately corresponds to the radial distance of the supporting flank from the axis. The retaining projection can have a run-up bevel facing away from the locking flank.The edge of the pressure plate comes into contact with this run-on bevel when the pressure plate is assigned to the piston. When the edge of the pressure plate comes into contact with the run-on bevel, the holding elements are pivoted into the release position. The spring bar bends elastically and then snaps back into the holding position in which the edge of the pressure plate is engaged over by the holding projection. The holding elements are connected to the plastic piston in particular using the same material. The plastic piston can have a radial slot so that it can also be inserted into cartridges or tubes whose inner diameter is slightly larger than the diameter of the edge of the front side. Compressing the gap reduces the circumferential length of the edge of the front side. The front side is formed in particular by a cup-shaped depression. Short description of the drawings

[0014] The invention is explained in more detail below using exemplary embodiments. They show: Fig. 1a longitudinal section through a cartridge press, Fig. 2enlarged, section II in Figure 1 , Fig. 3 enlarged, section III in Figure 2 , Fig. 4 in perspective and section a piston according to the invention connected to a pressure stamp 8, Fig. 5 a side view of the piston 11 attached to a pressure plate 8, Fig. 6 a perspective view of the in Figure 1 illustrated cartridge press with a cutaway, Fig. 7a perspective view of the piston looking at the rear 12, Fig. 7a a sectional view similar Figure 2 when attaching a pressure plate 8 to a piston 11, wherein the edge 8' acts on a run-up slope 19, Fig. 7b a subsequent illustration to Figure 7aafter the pressure plate 8 has brought holding members 16 into a release position, Fig. 7c shows a further subsequent illustration after the holding members 16 have assumed their holding position. Description of the embodiments

[0015] The exemplary embodiment of the invention relates to a cartridge press 1 having an actuating housing 2 in which a push rod 7 is linearly guided. By means of drive elements 5, the push rod 7 can be gradually displaced in a discharge direction by pivoting a drive lever 3 toward a handle 4. To relocate the push rod 7, actuation of a release lever 6 is required. Regarding the operation of such a cartridge press, reference is made to the relevant prior art, in particular to DE 20 2016 101 734 U1 or to the unpublished DE 10 2017 100 627.

[0016] At its free end, the pressure rod 7 carries a pressure plate 8 having an outer edge 8'. According to the invention, the pressure plate 8 is secured to a piston 11 by this outer edge 8' as follows. The pressure plate 8 has rotational symmetry.

[0017] The piston 11 is a single-material plastic body with a front side 13 with a circular outline. A peripheral edge 14 surrounding the front side 13 extends along a circular arc. The peripheral edge 14 surrounds a cup-shaped recess. A frustoconical surface adjoins the peripheral edge 14. Opposite the front side 13 is a rear side 12, which provides a receiving space 12' for accommodating the pressure plate 8.

[0018] The receiving space 12' is delimited by two opposing limiting ribs 15 extending along a circular arc, each forming a contact flank 15' for contact with the edge 8' of the pressure plate 8. The limiting rib 15 is divided into two halves by a radial slot, whereby the radial slot also divides the base body forming the cup-shaped recess.

[0019] Two holding members 16 are provided, diametrically opposed to each other—relative to the pressure rod 7 arranged in the axis of the pressure plate 8. Each of the two holding members 16 forms a holding projection 18 with a locking flank 23. In a holding position, the locking flank 23 lies above the edge 8' of the pressure plate 8 in order to clamp the pressure plate 8 to the piston 11.

[0020] The retaining projection 18 has a ramp 19 on its side opposite the locking flank 23 and is attached to a free end of a spring bar 17. The spring bar 17 extends—relative to the axis of the pressure plate 8—in the axial direction away from the base body of the piston 11, which has a frustoconical shape. The spring bar 17 is radially spaced from a circumferential arc defined by the profile of the peripheral edge 14. The distance of the spring bar 17 from the axis is less than the radius of the edge 14.

[0021] By radially bending the spring bars 17 against an elastic restoring force, the locking flanks 23 can be brought from a holding position extending over the edge into a release position in which the pressure plate 8 can be separated from the piston 11 in the axial direction.

[0022] In order to assign the pressure plate 8 to the piston 11, it can be displaced in the axial direction towards the rear side 12 ( Fig. 7a ). The edge 8' slides on the run-up slope 19 and bends the spring bar 17 in a radially outward direction ( Figure 7b ) until the retaining projection 18 snaps back into the holding position ( Figure 7c ).

[0023] According to the invention, a support arm 20 is attached to the retaining projection 18, and in particular to its free end. The support arm 20 protrudes radially outward and forms a support flank 21 with a circumferential line. This support flank 21 has approximately the same radial distance from the axis as the edge 14.

[0024] A projection 22 protrudes from the radially outermost portion of the support arm 20. Since the projection 22 protrudes axially from the support arm 20, it can be used as an actuating handle to pivot the holding member 16 from a holding position to a release position.

[0025] The support flank 21 forms, with an inner wall 10 of a cartridge 9 or a tube, a locking element that prevents the piston 11 inserted in a cartridge from separating from the pressure plate 8. The radial distance between the inner wall 10 and the support flank 21 is smaller than the radial length of the overlap of the locking flank 23 over the edge 8' of the pressure plate 8. If, for example, by applying a pull to the push rod 7 in the direction away from the piston 11, a force is applied to the locking flank 23 that generates a torque that urges the holding member 16 towards the release position, thus tending to bend the spring bar 17 in the radially outward direction, the support flank 21 abuts against the inner wall 10 of the cartridge 9 and thus prevents the locking flank 23 from losing its locking effect that overlaps the edge 8'.In the exemplary embodiment, it is particularly provided that the diameter of the rim 14 is slightly larger than the inner diameter of the tube forming the cartridge 9. The support flanks 21 extend along the same circumferential circle. If such a piston 11 is inserted into the cartridge 9, the radial slot 25 must be compressed slightly. The two opposing retaining members 16 must also be shifted slightly toward each other. The support flanks 21 then rest against the inner wall 10 with a slight spring preload.

[0026] In the exemplary embodiment, it is further provided that a window is formed between two spring bars 17, so that the support arm 20 or the holding projection 18 is connected by two spring bars 17 to the base body, which has a truncated cone shape.

Claims

1. A cartridge discharging device (1) for discharging a pasty compound out of a cartridge (9), which has an inner wall (10), comprising a piston (11) and a rear face (12), which can be acted upon by a pressure plate (8) fastened to a push rod (7), a front face (13) located opposite the rear face (12), and a retaining element (16), which, in a retaining position, secures the pressure plate (8) against the rear face (12) by means of a retaining protrusion (18), which engages over an edge (8') of the pressure plate (8), wherein the retaining element (16) forms a spring web (17), that fastens the retaining protrusion (18) to the piston (11) in a moveable manner into a release position in a direction away from the push rod (7), characterized in that the retaining element (16) has a support flank (21) configured to strike or about against the inner wall (10) of the cartridge (9) so as to prevent an escape of the retaining element (16) into the release position when the piston (11) is inserted into the cartridge (9).

2. The cartridge discharging device according to one of the preceding claims, characterized by a second retaining protrusion (18) located opposite the retaining protrusion (18), which in particular can also be elastically movable into a release position.

3. The cartridge discharging device according to one of the preceding claims, characterized in that the piston (11) has a contact flank (15') for abutting against the edge (8') of the pressure plate (8).

4. The cartridge discharging device according to one of the preceding claims, characterized in that the contact flank (15') is formed by a limiting rib (15).

5. The cartridge discharging device according to one of the preceding claims, characterized in that the support flank (21) is formed by a support arm (20).

6. The cartridge discharging device according to one of the preceding claims, characterized in that a run-on bevel (19) is located opposite a locking flank (23) of the retaining protrusion (18).