US3668751A

US3668751A - Apparatus for chamfering tablets

Info

Publication number: US3668751A
Application number: US50400A
Authority: US
Inventors: Haruji Saeki
Original assignee: Shionogi and Co Ltd
Current assignee: Shionogi and Co Ltd
Priority date: 1969-06-30
Filing date: 1970-06-29
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13
Also published as: DE2032347A1; CH511602A; GB1268477A; FR2051432A5

Abstract

An apparatus for chamfering the sharp edges of pharmaceutical tablets. The apparatus has abrading means having at least two moving surface portions having a grinding or abrading surface which is sufficiently hard and rough to scrape the tablets. A guiding member is disposed above the surface portions which has a channel interconnecting inlet and outlet openings and having a cross section permitting the unobstructed passage of the tablets while holding the tablets oriented in a predominantly upright yet slightly inclined position with one of the sharp edges toward the surface of the surface portions. Two grooved segments extend along parts of the length of the guiding member connected by a tubular segment. Each of the grooved segments extends across a respective moving surface portion along a line which intersects the direction of movement of the surface portion at an angle other than a right angle. The portions of the channel extending through each of the grooved segments is a groove opening out of the segment and opposed to the corresponding grinding and abrading surface portion and spaced therefrom to leave a small clearance between the segment and the surface portion. One of said grooved segments orients the tablets with one of the circular edges against the corresponding surface portion and the other of the grooved segments orients the tablets with the other of the circular edges against the corresponding surface portion. The tubular portion has the portion of the channel extending therethrough twisted, if necessary, to change the orientation of the tablets from the position with one edge against the surface portion to the position with the other edge against the surface portion.

Description

United States Patent [451 June 13, 1972 Saeki [54] APPARATUS FOR CHAMFERING TABLETS [72] Inventor: Haruli Saeltl, Suita, Japan 73] Assignee: Shionogl & Co., Ltd., Osaka, Japan [22] Filed: June 29, 1970 211 Appl. No.: 50,400

[30] Foreign Application Priority Data June 30, 1969 Japan ..44/5203i Aug. 28, 1969 Japan..... ....44/68424 May I 1, 1970 Japan ..45/40406 [52] U.S. Cl. ..29/76, 51/128 [51] Int. Cl. ..ll23d 67/00, B24b 7/00 [58] Field ofSearch ..29/76, 78;51/l10, 116,112, 51/128,130, 210

[56] References Cited UNITED STATES PATENTS 2,407,053 9/1946 Belade ..29/76 838,991 12/1906 Heller ..29/76 X 522,044 6/1894 Carlyle ..29/76 X 295,705 3/1884 Williams .....29/76 X 148,161 3/1874 Ames ..29/76 X R24,202 8/1956 Blood ..29/76 X 2,474,465 6/1949 Carlton ..29/76 2,067,566 1/1937 Field t ..29/76 1,544,083 6/1925 Whitten.. .....29/76 2,648,170 8/1953 Esters ..29/76 X 1,136,499 4/1915 Warner ..29/76 X FOREIGN PATENTS OR APPLICATIONS 1,124,785 3/1962 Germany ..29/76 Primary Examiner-Harrison L. Hinson Attorney-Wenderoth, Lind & Ponack [57] ABSTRACT An apparatus for chamfering the sharp edges of pharmaceutical tablets. The apparatus has abrading means having at least two moving surface portions having a grinding or abrading surface which is sufficiently hard and rough to scrape the tablets. A guiding member is disposed above the surface portions which has a channel interconnecting inlet and outlet openin and having a cross section permitting the unobstructed passage of the tablets while holding the tablets oriented in a predominantly upright yet slightly inclined position with one of the sharp edges toward the surface of the surface portions. Two grooved segments extend along parts of the length of the guiding member connected by a tubular segment. Each of the grooved segments extends across a respective moving surface portion along a line which intersects the direction of movement of the surface portion at an angle other than a right angle. The portions of the channel extending through each of the grooved segments is a groove opening out of the segment and opposed to the corresponding grinding and abrading surface portion and spaced therefrom to leave a small clearance between the segment and the surface portion. One of said grooved segments orients the tablets with one of the circular edges against the corresponding surface portion and the other of the grooved segments orients the tablets with the other of the circular edges against the corresponding surface portion. The tubular portion has the portion of the channel extending therethrough twisted, if necessary, to change the orientation of the tablets from the position with one edge against the surface portion to the position with the other edge against the surface portion.

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ATTORNEY S APPARATUS FOR CHAMFERING TABLETS BACKGROUND OF THE INVENTION l Field of the Invention The present invention generally relates to an apparatus for preparatory treatment of tableted articles. More particularly, the present invention concerns an apparatus for scraping circular edges of the tablets formed by a tableting press as a thickset cylinder which tablets can have spherical ends and for modifying the shape of such tablets so that it is more like an ellipsoid or a sphere.

Preferably, tablets, in general, are shaped such that each has an external form which resembles a sphere or an ellipsoid with a rounded peripheral edge if they are to be coated with sugar or cellulosic material after they are molded.

2. Description of the Prior Art The circumstances surrounding tablet manufacture are however very contrary to the preference, that is, since the tablets have hitherto been manufactured by the conventionally known tableting press of the punch-and-die type, the shapes of the formed tablets are generally such that each is composed of a side cylindrical wall which corresponds to the internal wall of the die cavity and a top and a bottom convex end walls which correspond to the concave operative heads of the punches, and eventually the lines along which said cylindrical wall intersects with the spherical end walls, constitute rather sharp circular edges.

Since each of the tablets molded in the aforedcscribed manner has a side cylindrical wall around which a groove with banks of coating material may develop during a coating process using such coating materials as sugars subsequent to the compacting process, manufacturers have been compelled to perform the coating operation by adding an additional thickness of the coating layer to fill up said groove, which operation requires excessive coating materials and prolongs processing time. Obviously, the above circumstances can equally be applicable to the case of film coating (with cellulosic materials).

It is therefore essential that the tablet prepared to be subjected to coating process to have the sharp circular edges reduced or at least relieved to reduce the sharpness of the edge lines, and for fulfilling these requirements there has hitherto been proposed a method wherein the shapes of the concave operative heads of the punches are modifies so as to have a compound concave sharp composed of a double or multiple sphere.

According to this method, the construction of the punches becomes very complicated with a consequent high production and/or tooling cost of the punches and shortening of the service life of the punches.

SUMMARY OF THE INVENTION It is therefore the primary object of the present invention to provide an apparatus for reducing or at least relieving the sharpness of the circular edges of the tableted articles as much as possible and allowing the shapes of such tablets to approach those of a sphere or an ellipsoid. It is another object of the present invention to provide an apparatus for preparative treatment interposed between a compacting process and a coating process of tableted articles, which apparatus is capable of minimizing the thickness of the material applied for coating the tablets.

DESCRIPTION OF THE DRAWINGS These and other objects of the present invention and attendant advantages thereof will be made apparent to those who are conversant with the art to which the present invention pertains by the following detailed disclosure of the specification and the appended claims, taken in conjunction with the accompanying drawings.

Embodiments of the present invention represented by FIGS. 1 through 7 are classifiable in the first group of the embodiments wherein at least one rotating disk having a flat grinding or abrading surface is employed as the moving member and only essential components are shown fragrnentarily or as a transparent body for facilitating the explanation, in which;

FIG. I is a plan view of an apparatus in accordance with such embodiments,

FIGS. la and lb are sectional views of the apparatus taken along the line X-X and Y-Y' of FIG. 1,

FIG. 2 is a plan view showing another embodiment,

FIG. 2a is a sectional view taken along the line X-X' of FIG. 2 while FIG. 2a is a sectional view analogous to FIG. 2a except for some modification made with regards to the arrangement of the components,

FIG. 3 is a plan view of an apparatus which belongs to the first group of the embodiments,

FIG. 3a is a sectional view of the apparatus taken along the line X-X' of FIG. 3 while FIG. 3b is a sectional view of the apparatus taken along the line Y-Y' of FIG. 3, with the assumption that the rotating disks are placed on parallel planes at different levels,

FIG. 4 is a plan view of an apparatus which still belongs to the first group of the embodiments,

FIGS. 44 and 4b are sectional views of the apparatus taken along the lines X-X and Y--Y' of FIG. 4,

FIG. 5 is a plan view illustrating another embodiment,

FIGS. 5a and 5b are sectional views of the apparatus taken along the lines XX' and Y-Y' ofFIG. 5, and

FIGS. 6 and 7 are sketchy perspective views of other embodiments wherein only essential components are shown in simple lines.

Another group of embodiments of the present invention is represented by FIGS. 8 through 11, wherein at least one rotational body having a curved grinding or abrading surface is employed as the moving member, and expediently designated as the second group, in which;

FIG. 8 is a perspective view of an apparatus which belongs to such embodiment,

FIGS. 8a, 8b and 8c are sectional views of the apparatus taken along the planes X, Y and Z of FIG. 8, respectively, and each of FIGS. 9, l0 and 11 is a perspective view of an apparatus showing another embodiment which belongs to the second group represented by FIG. 8.

Embodiments illustrated in FIGS. I2 through 15 can be classified in the third group wherein at least one endless belt or caterpillar having an infinite or continuous grinding or abrading surfaces and extending between pivoted pulleys or sprockets, is employed as the moving member, in which;

FIG. 12 is a perspective view of an apparatus in accordance with such embodiment,

FIGS. 12a, 12b and I2: are sectional views of the apparatus taken along the lines X-X', Y-Y' and 2-2 of FIG. 12,

FIG. 13 is a perspective view of another apparatus analogous to that of FIG. 12,

FIGS. 13a, 13b and are sectional views of the apparatus taken along the lines X-X', Y-Y' and 2-2 of FIG. I3,

FIG. 14 is a perspective view of another embodiment which still belongs to the third group illustrated in FIG. 12,

FIGS. 14a, 14b and 14c are sectional views taken along the lines X-X', Y-Y and 2-2 of FIG. 14, respectively; and

FIG. 15 is a plan view of a modified apparatus of the embodiment illustrated in FIG. 14.

In the following paragraphs, descriptions will be given in conjunction with the drawings wherein the parts or components having identical or corresponding functions are designated by the same reference characters or numerals throughout the several views which belong to the same groups.

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, there is provided an apparatus for chamfering tableted articles comprising essentially; at least one moving member bearing at least one grinding or abrading surface having a hardness and roughness sufficient for scraping the tablets and movable along said grinding or abrading surface and at least one guiding member disposed in the vicinity of said surface along a line which intersects with the direction of the movement of the surface at an angle other than a right angle, generally having an inlet and an outlet opening for the tablets and a channel interconnecting said openings and permitting unobstructed passage of said tablets, said channel has partially tubular sections and grooved sections for remainder, the portion having said grooved sections being kept in spaced opposed relationship to said grinding or abrading surface while holding said tablets in an upright but inclined posture or condition so that at least one side of one of the circular edges of the tablets is always in good contact with said surface, and the portion having said tubular section interposed between the grooved sections optionally has a function of reversing the angle of inclination of the tablet while allowing the passage of the tablet.

As a moving member in said apparatus, there can be used a rotating disk having a flat grinding or abrading surface, a couple or a combination of three or more of such rotating disks, a rotational body such as a cylinder, cone or conical frustum having a curved grinding or abrading surface or a simple or compound combination thereof, and an endless belt positioned between at least two pivoted pulleys or sprockets and having an infinite or continuous grinding or abrading surface or a combination thereof, and any other means capable of providing such surfaces can equally be employed.

As an abrading or grinding surface of the present invention, although any roughened surfaces having sufficient hardness and ruggedness for scraping the peripheral edges of the tablets can be employed, grinding members of hard stainless steel or tool steel treated with hard chrome plating, are generally preferred. In realizing the present invention, such members can a rotating disk, cylinder, cone, conical frustum or element of an endless abrading surface, which can be driven by separate driving means.

The guiding means of the present invention is one which is capable of holding tablets in an upright but somewhat inclined posture or condition, in other words, generally upright with a moderate angle of inclination with respect the surface so that at least one side of the circular edges of the tablets is always in good contact with said surface. The guiding means must be capable of transferring said tablets therethrough in a direction which intersects with the direction of the movement of the grinding or abrading surface, namely the moving member, at an angle other than a right angle.

The tubular portion of the guiding member interposed between the grooved portions is preferably designed to have the ability of reversing the angle of orientation of the tablets with respect to the grinding or abrading surface while transferring the tablets therethrough in order to obtain even chamferings of the circular edges of the tablets. The interior must therefore be twisted in the direction of its length in such case.

A multiplicity of the guiding members can be provided for one abrading or grinding surface of the moving member, and although various manners of arranging the member can be exemplified, a parallel disposition is the most preferred in view of the necessity of providing feeding and expelling means for the tablets.

Typical representatives of the embodiments of the present invention can expediently be classified into three groups, and those which fall within the first one of such groups will be illustrated in FIGS. 1 through 7, wherein at least one disk-type moving member which rotates about its center is employed.

In FIG. 1, opposed to a rotating disk D with a single grinding or abrading surface 1 having a shape like a doughnut type sound disk, is disposed an arcuate guiding member 2 having a radius of curvature which is slightly larger than that of the outer circle of the rotating disk.

The rotating disk D is rotatably driven in the direction of the arrow of the drawing, i.e., counter-clockwise direction by a driving means (not shown).

The guiding means is shown in the drawing as being made with a transparent material to meet the convenience of illustration, and is supported by a bracket or the like (not shown) on a stationary frame (not shown) of the apparatus. The guiding means is composed of three segments, i.e., the

segments

21, 22 and 23; among them, the

segments

21 and 23 facing the grinding or abrading surface 1 are grooved sections wherein the

grooves

24 and 26 are exposed to or open toward said surface (FIG. la); while the segment 22 which does not face the surface 1 has a tubular section like a tunnel 25, the bottom thereof is closed (FIG. lb).

The tunnel 25 and the

grooves

24 and 26 are all interconnected to form a single channel and this extended channel is capable of permitting unobstructed passage of the tablet therethrough.

The

grooves

24 and 26 are designed and constructed to have a cross section in the shape of an inclined rectangle with a width sufficient to pass the tablets. They must hold the tablet in an upright but somewhat inclined posture or condition with the sharp edge of the tablet against the grinding or abrading surface so that at least one side of the circular edges of the tablet is always in good contact with said surface.

The angle of orientation of the tablet relative to the surface is moderate (about 30) and can be varied with the original shape of the tablet. Furthermore, it may be varied over the length of the groove to obtain a round edge on the tablet. It however usually is fixed determined to meet the convenience of tooling, and a sufficient result can be obtained by a fixed orientation because of the small clearance between the tablet and the side wall of the groove.

Since said orientation must conform to the posture of the tablet 3 in order to make the tablet follow the moving grinding or abrading surface, in other words, to cause it to be dragged by the surface, the inclination of the groove 24 must be opposite to that of the groove 26 as is clearly shown in the sectional view of FIG. la.

Therefore, the tunnel 25 of the segment 22 must have a cross-section in the shape of a rectangle and be twisted in the direction of its length so that the angle of the orientation of the travelling tablet is reversed within the tunnel.

When a tablet 3 is fed from the inlet opening 27 at the right extreme of the guiding member 2, it is transferred through the groove 24 in the direction indicated by the arrow receiving a component force due to the rotational movement of the grinding or abrading surface 1 against which the tablet 3 is engaged, the particular circular edge of the tablet which contacts the surface 1 being scraped or bevelled during this transferring operation.

The tablet is then pushed into the reversed tunnel 25 where the angle of orientation is the reversing operation of the tunnel. After being expelled from the tunnel 25, the other circular edge is scraped while it is transferred along the second groove 26, and the tablet is finally expelled from the outlet opening 28 at the left extreme of the guiding member 2.

Although no force is exerted on the tablet 3 while it is within the tunnel 25, the tablet can be forced to travel, because it is being pushed by the succeeding tablets.

If specifically required, a transfer by the aid of gravitation can be obtained by tilting the whole apparatus.

The tablets processed and expelled from the outlet opening 28 in the previously described manner, have a shape which is more like an ellipsoid because the circular edges are evenly chamfered and smoothed.

Apparently, if treated as aforedescribed, any subsequent treatment for the tablet such as coating operation will be extremely simplified.

The embodiments illustrated in FIGS. 2 through 7 each belong to the first group described in detail relative to the embodiment shown in FIG. 1, and are based on the same concept of the construction of the last mentioned embodiment, wherein modifications and variations concerning the number and the manner of relative desposition of the moving members and the guiding members, the manner of driving of the moving members and the contours of the guiding members, i.e., the routes along which the tablets travel, are made, and illustrations concerning the parts and components having functions almost identical or corresponding to that already elucidated in connection with FIG. 1 are omitted or at least simplified.

In the embodiment illustrated in FIGS. Z-Za, a linear guiding member 2 is provided bridg'ng two rotating disks D, and D each bearing the grinding or abrading surfaces 1 and l disposed in the same plane and having their adjacent portions rotating in opposite directions as indicated by the arrows in the drawing.

Although the whole apparatus may be tilted in order to insure the smooth transferring of the tablets 3 within the intermediate region 22, such utilization of gravitation can be dispensed with if the grinding or abrading

surfaces

1 and 1 are placed on planes which are parallel but on different levels as is illustrated in FIG. 2a.

An embodiment shown in FIGS. 3-30 includes; a couple of rotating disks D and D bearing the grinding or abrading surfaces I and l disposed coaxially in the same plane or a couple of planes which are parallel with each other but on the different levels, which disks are rotating in opposite directions, and the guiding member 2 having a tablet transferring channel which is bent sharply but extending over both surfaces and the function thereof is almost the same as that illustrated above.

Furthermore, FIG. 3a is a sectional view of such apparatus showing the case where the both surfaces are placed on same plane while the sectional view of FIG. 3b shows the apparatus in which the surfaces are placed in planes on different levels.

According to the construction of this embodiment, an additional advantage is obtainable in that a multiplicity of the guiding members can conveniently be disposed over a single pair of grinding or abrading surfaces.

Although the arrangement of the members in the embodiment illustrated in FIGS. 4-4b is almost identical to that shown in FIG. 3 with the exception that the grinding or abrading surfaces 1 and I are facing in opposite directions, the embodiment is unique in that it can dispense with the function of the intermediate region 22 of the guiding member 2 that reverses the angle of orientation of the tablet with respect to the surfaces for evenly chamfering both circular edges of the tablet, and therefore the groove 24 at the region 2! of the guiding member 2 is open downwards while the groove 26 of the region 23 is open upwards.

In the embodiment shown in FIGS. 5-5b, the tablets 3 run through the folded guiding member 2 between inner circumference and the outer one of the single doughnut shaped sound disk type of grinding or abrading surface I, wherein the angle of orientation of the tablet 3 with respect to the surface is reversed in the tunnel of the intermediate region 22 of the guiding member 2 which projects to the outside of the periphery of the grinding or abrading surface supported by the rotating disk.

FIGS. 6 and 7 are just sketchy illustrations of other variations which still fall within the first group of the embodiments wherein only the positional relationships between the grinding or abrading surfaces and the guiding member are illustrated.

Although the guiding members are shown as strings and rotating disks are shown by simple lines in FIGS. 6 and 7, the unshown tablets are held so as to be pushed against the surface and have their angle of orientation reversed while being transferred along the member.

A combination of a rotating disk having a couple of grinding or abrading surfaces 1 and l on opposite sides, i.e., face and back thereof and a guiding member 2 surrounding the disk are provided in the embodiment shown in FIG. 6.

Another combination of a couple of disks coaxially pivoted one above opposite other and rotating in the directions, having grinding or abrading

surfaces

1 and 1 on each of the front faces, and a folded guiding member 2 streching over the both surface is shown in FIG. 7.

A series of embodiments belonging to the second group, are illustrated in FIGS. 8 through 10, wherein the moving members are rotational bodies other than disks such as a cylinder, cone, hyperbolic body (hand-drum shape) or a combination of two or more of such bodies, having at least one grinding or abrading surface other than a plane, and the guiding members extend along said surfaces.

In FIGS. 8-8c, the moving member is composed of a couple of cylinders 10! and 102 which are pivoted eoaxially but driven to rotate in opposite directions as indicated by the arrows in the drawing, by driving means (not shown), having grinding or abrading surfaces on their side walls.

A guiding member 130 is disposed along the side walls while spirally surrounding the cylinders 10! and 102 bearing the grinding or abrading surfaces 1 l l and I2]. It is supported by a bracket (not shown) on a stationary frame (not shown) of the apparatus so that there is a small clearance between it and the grinding or abrading

surfaces

111 and 121.

Of the guiding member 130, the

segments

131 and 133 which face the grinding or abrading surfaces 11! and 121 are grooved sections having grooves 130a and 130: while the interrnediate segment I32 has a tubular section with a tunnel 130i).

These grooves and tunnel which are inclusively represented by numeral 130 extend from the uppermost portion to the lowermost portion of the guiding member 103 and are capable of permitting the unobstructed passage of the tablet therethrough.

The grooves 130a and 130:- which are opposed to the grinding or abrading surfaces I

l

1 and 121 must have a width, depth and inclination sufficient to hold the tablet upright with a moderate angle of orientation relative to the surface.

On the other hand, the tunnel 130D must have the function of changing the direction of the tablet's travel and of reversing the angle of orientation of the tablet relative to the surface.

In the above described construction, a tablet I04 introduced into the channel 130 from the uppermost portion of the guiding member 103, is held by the groove 130a and contacts the grinding or abrading surface III at the circular edge on one side of the tablet side (see, sectional view of FIG. 8a), while being transferred down through the groove 130a gradually with the rotation of the moving member in the direction indicated by the arrow in the drawing until it reaches the tunnel l30b at intermediate segment I32 (sectional view of FIG. 8b).

The tablet 104 has its angle of orientation relative to the surface reversed and it is introduced into the groove 1300 to be brought into contact with the surface at the circular edge of the other side of the tablet (sectional view of FIG. 8c).

Since the inner surface of the channel 130 is designed and finished to contact with the tablet with suitable friction while permitting an adequate amount of slip between them, the tablets are dragged by the grinding or abrading surface while being permitted some degree of rotational movement so that both circular edges are chamfered evenly during the travel and therefore the shape is made more like an ellipsoid to attain the object of the present invention.

The embodiments illustrated in FIGS. 9 through II are based on the same concept of the construction of the embodi ment just described and therefore the illustrations concerning the parts and components having functions almost identical or corresponding to that already elucidated in connection with FIG. 8 are omitted or at least simplified.

In the embodiment shown in FIG. 9, the moving member is composed of a couple of conical frustums I01 and 102 and a rod connecting the frustums at their portions of smaller diameter and the whole assembly rotates in the direction of the arrow, and a guiding member 103 helically twines around both of the

frustums

101 and 102 which member has a lower portion wherein the tablet 104 travels along the back side of the lower frustum.

The embodiment illustrated in FIG. 10 includes a single moving member of hand-drum shape 101, which shape may, more specifically, be designated as a hyperbolic body, having a hyperbolically curved grinding or abrading surface and a substantially linear but twisted guiding member 130.

A modification of this embodiment is shown in FIG. 11, wherein a couple of hyperbolic bodies are stacked and the function of the embodiment is self-explanetory.

Further alternatives of the embodiments of the present invention which fall within the third group previously classified, are shown in FIGS. 12 through wherein the grinding or abrading surfaces are formed on the moving member in a fonn of an endless belt like member extending between at least two pulleys or sprockets. 1n the embodiments, each element of the endless belt-like member is designed and constructed to have an outside grinding or abrading surface which forms an infinite or continuous surface capable of scraping the tablet. In addition to such rigid components, the surface can also be formed on an endless belt of flexible material like a "belt grinding tool".

In the embodiment shown in FIGS. 12-120 of the drawings, a belt-like member composed of elements each having a grinding or abrading surface 211 and extending between a couple of pulleys 2I2 and 212', is driven to run steadily in the direction of the arrow of the drawings by driving means (not shown).

The guiding member 220, although it is expediently shown as a transparent body in the drawing, is supported by a bracket or the like (not shown) on a stationary frame (not shown) of the apparatus and is composed of the segments designated by the

numerals

221, 222, 223, 224 and 225.

The inlet opening 226 provided at the left extreme of the segment 221 is connected with the outlet opening 227 at the right extreme of the segment 225 through tunnels and grooves along which the tablet 203 travels.

The interiors of the

segments

221 and 225 are formed as tunnels 221' and 225' with moderate down grades in the direction of the tablets travel permitting a smooth passage of the tablet 203. The

segments

222 and 224 are formed as grooves 222 and 224', Le, the sides facing the grinding or abrading surface 211 are cut open.

The cross sections of these grooves are substantially rectangular and are oblique so that they can hold the tablet in an upright but oriented posture or condition with the sharp edges against the grinding or abrading surface 211.

The angle of inclination of the groove 222' is however made reverse to that of the groove 224' and by doing so, the tablet 203 can follow the movements of the grinding or abrading surface 211. The curved segment 223 has a twisted tunnel 223' therethrough, because the tablets 203 must have their direction of travel changed as well as having the angle of orientation relative to the surface changed while being transferred in the tunnel 223'.

The channel composed of these grooves and tunnels may have a moderate down grade in order to promote smooth passage of the tablet 203.

The tablet 203 which has been supplied from the inlet open ing 226 and passes through the tunnel 221, has one of the circular edges which is in actual engagement with the grinding or abrading surface 211 chamfered while being transferred along the groove 222'. In the next moment, the tablet 203 has its angle of orientation relative to the surface reversed during the travel along the tunnel 223' and then the other circular edge is chamfered while the tablet is being transferred along the next groove 224', and the tablet is expelled from the outlet opening 227 after being introduced into and driven through the tunnel 225'.

Tablets processed in the previously described manner and expelled from the outlet opening 227 have both circular edges chamfered and are shaped more like an ellipsoid or sphere.

Apparently, any subsequent treatments of thus processed tablets such as coating will be greatly simplified.

The embodiments shown in FIGS. 13 through 15, are possible variations of relative arrangements of the guiding members and the moving members, wherein the functions of the components equivalent to those of the apparatus shown in FIG. 12, are almost identical to those described relative to FIG. 12, and therefore the detailed explanations will be omitted if they are common and unduly duplicated.

In the embodiment shown in FIGS. 13-130, a combination of a couple of belt-like members 201 and 201' (shown partially in the drawing) with continuous grinding or abrading surfaces 211 and 211' having centerlines of the movements which intersect with each other and a substantially linear guiding member 202 which bridges both moving members 211 and 211' are provided. The direction of the movement of the surface 211 is made to run opposite that of the surface 21 I as is indicated by the arrows.

The embodiment shown in FIGS. 14-14:: is comprised of a couple of belt-like members 201 and 201' (shown partially in the drawing) each having an infinite grinding or abrading surface 211 or 211' disposed in parallel and a V-shaped guiding member 202 extending across both belt-like members, and is substantially the same as that described in FIG. 13 except for the bent guiding member and parallel disposition of the beltlike members.

The construction of this embodiment is however very convenient if a multiplicity of guiding members are provided in parallel for a pair of the belt like members, and the conveniency is supported by the exemplarily shown plan view of FIG. IS.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims as well as the foregoing specification as indicating the scope of the invention.

What is claimed is:

1. An apparatus for chamfering the sharp edges of pharmaceutical tablets, comprising abrading means having at least two moving surface portions having a grinding or abrading surface which is sufficiently hard and rough to scrape the tablets, and at least one guiding member disposed above said surface portions, said guiding member having an inlet and an outlet opening at opposite ends for receiving and discharging the tablets and a channel interconnecting said openings and having a cross section permitting the unobstructed passage of the tablets while holding the tablets oriented in a predominantly upright yet slightly inclined position with one of the sharp edges toward the surface of the surface portions, said guiding member having at least two grooved segments along parts of its length and at least one tubular segment connected between said grooved segments, each of the grooved segments extending across a respective moving surface portion along a line which intersects the direction of movement of the surface portion at an angle other than a right angle, the portions of said channel extending through each of said grooved segments being a groove opening out of the segment and being opposed to the corresponding grinding and abrading surface portion and spaced therefrom to leave a small clearance between the segment and the surface portion, one of said grooved segments orienting the tablets with one of the circular edges against the corresponding surface portion and the other of said grooved segments orienting the tablets with the other of the circular edges against the corresponding surface portion, and said tubular portion having the portion of said channel extending therethrough twisted to change the orientation of the tablets from the position with one edge against the surface portion to the position with the other edge against the surface portion.

2. An apparatus a claimed in claim I further comprising a means for supporting said abrading means and guiding member including a stationary frame, means coupled to said abrading means for driving said abrading means, means for feeding the tablets to be processed into the inlet opening of said guiding member and means for receiving the tablets from the outlet of said guiding member and transferring them to a subsequent process.

3. An apparatus as claimed in claim 1 in which the angle at which said guiding portions extend is an angle with respect to the direction of movement said surface portions.

4. An apparatus as claimed in claim I in which said surface portions of said abrading means are in the same plane.

5. An apparatus as claimed in claim 1 in which said surface portions of said abrading means are in different parallel planes, the surface portion with which the tablets first come into contact with being above the other surface portion.

6. An apparatus as claimed in claim 1 in which said abrading means is a single rotating annular member and said grooved segments extend across different portions of said member.

7. An apparatus as claimed in claim 6 in which the first grooved segment in the direction of movement of the tablets extends across one portion of the annular member from the outer periphery to the inner periphery thereof, the tubular segment extends across the interior of the annular member, and the other grooved segment extends across a second portion of the annular member from the inner periphery to the outer periphery thereof.

8. An apparatus as claimed in claim 7 in which the guiding member extends across the annular member in a curve having a radius of curvature greater than that of the outer periphery of the annular member.

9. An apparatus as claimed in claim 6 in which the first grooved segment in the direction of movement of the tablets extends across one portion of the annular member from the inner periphery to the outer periphery thereof, the tubular member extends from one point on the outer periphery to a second point on the outer periphery. and the other grooved segment extends across a second portion of the annular member from the outer periphery to the inner periphery thereof.

10. An apparatus as claimed in claim 1 in which said abrading means is a plurality of annular rotating members and said grooved segments extend across respective portions of the different annular rotating members.

11. An apparatus as claimed in claim 10 in which said annular rotating members are side by side and rotatable around parallel axes, and said guiding member extends in a straight line across the two rotating members from the inner periphery of one across the outer periphery thereof and from the outer periphery of the other across the inner periphery thereof.

12. An apparatus as claimed in claim 10 in which said annular rotating members are concentric.

13. An apparatus as claimed in claim 12 in which said guiding member extends from the inner periphery of the inner annular member to the outer periphery thereof and from the inner periphery of the outer member to the outer periphery thereof.

14. An apparatus as claimed in claim 13 in which said annular members both have their grinding or abrading surfaces facing in the same direction.

15. An apparatus as claimed in claim 10 in which said annular rotating members are coaxial and are one above the other.

Claims

2. An apparatus as claimed in claim 1 further comprising a means for supporting said abrading means and guiding member including a stationary frame, means coupled to said abrading means for driving said abrading means, means for feeding the tablets to be processed into the inlet opening of said guiding member and means for receiving the tablets from the outlet of said guiding member and transferring them to a subsequent process.

4. An apparatus as claimed in claim 1 in which said surface portions of said abrading means are in the same plane.

9. An apparatus as claimed in claim 6 in which the first grooved segment in the direction of movement of the tablets extends across one portion of the annular member from the inner periphery to the outer periphery thereof, the tubular member extends from one point on the outer periphery to a second point on the outer periphery, and the other grooved segment extends across a second portion of the annular member from the outer periphery to the inner periphery thereof.