RU2510672C2 - Multiposition rotary press - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and can be used in pyroelements shaped to tapered tablets. Proposed press comprises pyromix batcher, compacted tablet discharge flute and rotor equipped with tool frames. Every said frame comprises top and bottom male dies aligned to displace in synchronism opposite each other. Female dies with bottom composed by bottom male dies are arranged between male dies. This press incorporates a control system. Pyromix batcher is composed of rotary disc articulated with rotor provided with metering through holes arranged along the edges and top table with discharge hole secured under the disc. Said discharge hole is inclined through angle larger than that of natural slope of pyromix. Female dies are shaped to cone inversed to pressing direction. Female die taper K=(D-d)/2h is selected from enclosed relationship.

EFFECT: simplified design, lower labour input to adjustment.

2 dwg

Description

The invention relates to presses for special purposes for the manufacture of tablets in molds placed around the circumference of a rotating drum, and is intended for pressing pyroelements.

The level of the art is characterized by a rotary tablet machine described in the invention SU 831628, B30B 11/12, 1981, comprising a working rotor with a horizontal axis of rotation, bearing tool blocks mounted on the periphery, whose coaxial vertical punches located on different sides of the matrix, interact with pressure rollers mounted on eccentric shafts installed in the frame.

The pressed tablet ejection mechanism includes a tablet pre-separation roller mounted in a copier (cam) mounted on an eccentric axis and a tablet ejector coaxial to the lower punch from the die to the level of a horizontally located puller.

The disadvantage of the described press is the unsatisfactory quality of the finished tablets, which is due to the presence of microcracks that arise in the material as a result of relaxation of residual stresses after a sharp release of the pressing pressure.

In addition, there may be cases of sticking of the tablet to the upper punch, which in this case is destroyed by the puller or fed into the matrix during subsequent pressing, which creates an emergency situation, which in the case of the manufacture of pyroelements can cause ignition.

More perfect is the multi-position press according to patent US No. 3063390, nat. class 107-1, 1962, which, according to the technical nature and the number of matching features, was chosen as the closest analogue to the proposed one.

The well-known press contains a slide-type dispenser of powder material connected to the track control system, a discharge tray of compressed tablets, a rotor for moving and positioning the tool blocks, each of which includes a mounted coaxial matrix with the possibility of oncoming movement, an upper punch kinematically closed with a cam, and a lower ejector, mounted on a support that serves as the movable bottom of the matrix.

A feature of the well-known press is that the punches and pushers, when positioning, interact with autonomous means of vibrational force, which contributes to a denser packing of the powder material and, most importantly, prevent it from sticking to the tool.

A disadvantage of the known multi-position rotary press is the complexity of the design of autonomous means of vibration exposure to punches and ejectors, precision manufacturing and commissioning accuracy.

In addition, the vibrational compaction of the pyrotechnic composition during technological operations in the press is unacceptable due to the inevitable separation of the mixture, which will lead to anomalies in the functional parameters of the purpose of the pyroelements.

The technical problem to which the present invention is directed is to simplify the design and commissioning of a rotary press without losing its functional reliability in the manufacture of high-quality pyroelements that meet the specified requirements of form and function.

The required technical result is achieved by the fact that in the well-known multi-position rotary press for making conical tablets from a pyrotechnic mixture containing a volumetric pyrotechnic mixture dispenser, a discharge tray of compressed tablets and a rotor carrying tool blocks, each of which includes upper and lower punches coaxially located in profiled guides with the possibility of power closure, respectively, with a pressure cam and a stationary support, and oncoming synchronous movement, races placed between the upper and lower punches of the tool blocks of the matrix with the bottom formed by the lower punches, as well as a control system for the synchronous movement and positioning of the tool blocks of the rotor, while the volumetric batcher of the pyrotechnic mixture is made in the form of a rotary disk kinematically connected to the rotor with uniform through-holes evenly distributed along the periphery holes and fixed under the said disk and adjacent countertops with the discharge window, tilted at an angle exceeding the angle e natural to the slope of the pyrotechnic mixture, ensuring its direction in the matrix that are configured to reverse the direction of the pressing cone, with the taper of the matrix K = (D-d) / 2h is selected from the relation:

0.05d / h≤K≤0.1d / h,

Where D is the maximum diameter of a tablet made of pyrotechnic material;

d is the minimum diameter of the tablet;

h is the height of the tablet,

and the upper punch is made with the possibility of separation from the tablet after the implementation of the working stroke of the pressing and subsequent ejection from the matrix of the tablet located on the lower punch, free from stationary support.

Distinctive features of the proposed technical solution ensured the safety of the manufacture of pyroelements by means of simple structural means by automatically pressing from a pyrotechnic mixture in the form of a cone-shaped tablet, whose diametric dimensions within the limits of the normalized tolerance field are guaranteed by the matrix design.

The rigid kinematic connection of the dispenser with the rotor ensured the synchronization of the volumetric portioned dosing of the treated mixture by gravity with the cycle of working operations at a common positioning rate.

The implementation of the dispenser in the form of a rotary disk with equally distributed along the periphery of the measuring holes adjacent to the countertop, is the simplest mechanism for automatic volumetric dosing of bulk material directly from the hopper.

The inclination of the through groove of the countertop with the direction into the funnel of the matrix at an angle exceeding the angle of repose of the pyrotechnic mixture ensures that the dose of the processed material is gravity poured into the tool block from its measured holes that are alternately aligned when the metering disc is rotated.

The execution of the matrix with the opposite direction of pressing by the cone prevents the pressed pyroelement from sticking to the upper punch, ensuring their mechanical separation.

The implementation of a cone-shaped matrix with a difference in the diameters of the lower and upper ends, not exceeding the established tolerance for the nominal dimension of the pyroelement, meets the technical requirements for the geometry of the manufactured functional product.

Reversing the upper punch after pressing the tablet makes it possible to forcefully separate them, since the tablet is held in the cone of the matrix, providing a break in the punch, which then acts as an ejector of the finished pyroelement from the matrix, together with a detachable bottom holding the tablet at the level of a horizontal puller.

The optimized matrix taper range technologically provides automatic reliable extraction of an adequately compressed pyroelement tablet, the geometric parameters of which are guaranteed not to go beyond the normalized tolerance field on its diameter.

Therefore, each essential feature is necessary, and their combination in a stable relationship is sufficient to achieve a novelty of quality that is not inherent in the characteristics of disunity, that is, the technical problem posed in the utility model is not solved by the sum of the effects, but by a new super-effect of the sum of the attributes.

The invention is illustrated by drawings, which have a purely illustrative purpose and do not limit the scope of the claims of the totality of the features of the formula. The drawings schematically depict:

figure 1 is a General view of a rotary press;

figure 2 - scan working cycle of the tool block.

The proposed press contains a technological rotor 1 carrying tool blocks, which is kinematically connected with the drive 2 of its rotation.

Each tool unit includes coaxially located upper and lower punches 3 and 4, which are in the working position in power and geometric closure with a pressure cam 5 and a stationary support 6, mounted on a traverse 7 and frame 8, respectively.

The punch 3 is installed on the slider 9, and the punch 4 - on the slider 10, which are respectively associated with profiled guides 11, 12 of their longitudinal movements.

The lower punch 4 is functionally made in the form of a detachable bottom of the matrix 13 of the tool blocks.

Between the punches 3, 4 of the tool blocks are the matrices 13 installed in the gear disk 14, rigidly connected with the rotor 1 and which is engaged with the gear 15 of the dispenser.

The gear 15 is rigidly connected with the rotary disk 16, equipped with equally dimensioned through holes 17.

Under the rotary disk 16, a counter top 18 adjacent to the bottom is secured with an unloading window 19, with which holes 17 carrying a portion of the pyrotechnic mixture are alternately aligned.

The unloading window 19 is inclined at an angle exceeding the angle of repose of the pyrotechnic mixture, and is directed to the funnel 20 for reloading the technological powder material into the matrix 13.

To the left of the drawing, over the rotary disk 16 there is a hopper 21 with a powder pyrotechnic mixture for the manufacture of extruded pyroelements.

A feature of the proposed design of the press is that the tablet-forming matrix 13 is made with the cone pressing in the opposite direction, the angle of inclination of the generatrix of which is uniquely associated with the geometric parameters of the manufactured pyroelement and the tolerance on the diameter of its tablet.

The configuration of the pyroelement tablet, according to the technical requirements and in accordance with the tolerance “T” for the nominal diameter “D”, is presented in the drawing, where for the pyroelement ⌀10 _-2 mm the dimensions are: D _max = 10 mm, D _min = 8 mm, h = 10 mm, T / 2 = 1 mm.

The taper "K" of the proposed matrix 13 of the pressing tool is selected from the following ratios of the overall parameters of the pyroelement:

K = T / 2 / h = (D-d) / 2h,

where the design diagram shows:

D is the maximum diameter of the tablet;

d is the minimum diameter of the tablet;

h is the height of the tablet;

α is the angle of inclination of the generatrix of the cone of the matrix 13.

The taper of the pyroelement tablet (K = tgα) must meet two conditions:

- do not exceed the ratio of the tolerance of the diameter of the tablet T = (D-d) to its height h, namely: K≤T / 2 / h;

- be large enough to provide mechanical separation of the compressed tablet from the punch 3, without the occurrence of continuity defects during relaxation of the material.

For defect-free separation of the punch 3, it is necessary that the force of adhesion at the end of the punch 3 with the tablet does not exceed the maximum allowable force for the tablet material in tension: P≤ [P].

The force arising from separation from the end of the compressed tablet will be equal to:

P = πσ _c d ^2/4,

where σ _c is the specific adhesion force of the tablet material with the surface of the end face of the punch 3.

Assuming that the normal stresses that occur during tension in a tablet are uniformly distributed along its height, the maximum allowable force will be:

, $$\left[P\right]=\pi {\sigma }_{\mathrm{at}}{D}_{\mathrm{from}}^2/\mathrm{four}$$

,

where D _c = (D + d) / 2 is the average diameter of the tablet; σ _in - tensile strength of the tablet material.

Introducing D = 2K · h + d, this expression can be reduced to the form: [P] = πσ _in (Kh + d) ^2/4.

Hence, the condition of defect-free separation of the punch 3 from the tablet can be written as:

(K · h / d) ² + 2K · h / d-σ _c / σ _at ≥0.

The solution to this equation is written as:

Given that for pyrotechnic tablets, the ratio σ _c / σ _B ≈ 0.1, and T ≈ 0.2 d, then the taper of the matrix 13 should lie within:

0.05d / h≤K≤0.1d / h.

For the selected geometrical parameters of the pyroelement, the taper of the matrix 13 is selected from the ratio: 0.06≤K≤0.08, which is guaranteed to fit into the tolerance area for the diameter of the pyroelement tablet ⌀10 _-2 mm.

A pyroelement tablet with a nominal diameter D = 10 mm and a height h = 10 mm of the proposed shape, taking into account the range of technological restriction of the taper, has d _max = 8.8 mm, ad _min = 8.4 mm.

In this case, after depressurization of the molding of the tablet, in its material, as shown by experimental work, there are no cracks, shells and delaminations that violate the functionality of the pyroelement, causing combustion instability with attenuation and jumps in the burning rate.

Therefore, the pyroelements made in the rotary press according to the invention are guaranteed to provide the specified parameters of stable burning of equipment in critical products.

The rotary press operates as follows.

Bulk material (prepared pyrotechnic mixture) from the hopper 21 fills the volume of the combined hole 17 of the rotary disk 16.

When the gear 15 is rotated, under the action of the gear disk 14 of the rotor 1, the disk 16 is adequately rotated, as a result of which the bulk portion of the technological mixture in the through hole 17 is cut off from the volume of the hopper 21 and transferred, moving along the countertop 18, to the inclined window 19.

When combining the through hole 17 of the disk 16 with the inclined window 19 in the countertop 18, a portion of the pyrotechnic mixture is gravitationally poured through the funnel 20 into the corresponding matrix 13, which is covered from below by the punch 4 (figure 2), which is connected as a split bottom to the matrix 13 under the action of the cam 12 .

When the rotor 1 is rotated, the lower slider 10 kinematically closes with the power support 6, rigidly fixing the punch 4 in the matrix 13, and the punch 3 with the slider 9, the counter-movable profile of the pressure cam 5, is lowered into the matrix 13.

As a result of the oncoming synchronous movement of the punches 3, 4 in the matrix 13, a portion of the pyrotechnic mixture is pressed into a cone-shaped pyroelement tablet.

Then, the slider 10, moved by the rotor 1 on the cam 12, is released from the restriction of the support 6, and the punch 3, reversibly rising by the profile of the cam 11, is torn off from the formed tablet, after which, forcibly lowering, pushes the tablet and punch 4 through the matrix 13 to the discharge level, which is determined by the position of the slider 10 on the cam 12.

Next, the punch 3 rises to its original position, and a horizontal puller (not shown conditionally) pushes the tablet from the end of the punch 4 into the outlet tray.

Next, the cycle of work is repeated.

A comparative analysis of the proposed technical solution with identified analogues of the prior art, from which the invention does not explicitly follow for a pyrotechnic specialist, showed that it is unknown, and taking into account the possibility of serial production of pyroelements in the proposed press, we can conclude that the patentability conditions are met.

Claims (1)

A multi-position rotary press for manufacturing conical shaped tablets from a pyrotechnic mixture, characterized in that it contains a volumetric pyrotechnic mixture dispenser, a discharge tray of compressed tablets and a rotor carrying tool blocks, each of which includes upper and lower punches coaxially arranged in profiled guides with the possibility of power circuit, respectively, with a pressure cam and a stationary support, and oncoming synchronous movement, located between the upper and lower point the tool blocks of the matrix with the bottom formed by the lower punches, as well as a control system for the synchronous movement and positioning of the tool blocks of the rotor, while the volumetric batcher of the pyrotechnic mixture is made in the form of a rotary disk kinematically connected with the rotor with uniform through holes evenly distributed along the periphery and fixed under the aforementioned disk and adjacent countertops with an unloading window inclined at an angle exceeding the angle of repose of the pyrotechnic cm if you ensure its direction in the matrix, which are made with the opposite direction of pressing by a cone, while the taper of the matrix K = (Dd) / 2h is selected from the relation:
0.05d / h≤K≤0.1d / h,
where D is the maximum diameter of the tablet made of pyrotechnic material;
d is the minimum diameter of the tablet;
h is the height of the tablet,
and the upper punch is made with the possibility of separation from the tablet after the implementation of the working stroke of the pressing and subsequent ejection from the matrix of the tablet located on the lower punch, free from stationary support.

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