Automatic Centrifugal Barrel Finishing Apparatus

Abstract

An automatic centrifugal barrel finishing apparatus is described, in which all processes are operated in due order determined by a sequence program using a sequence controller. The device includes an opening and closing apparatus for the lid, a discharging apparatus for the finished materials, a charging apparatus for charging unfinished materials and driving motors for the barrels between a pair of turrets.

Description

BACKGROUND OF THE INVENTION

This invention relates to an automatic centrifugal barrel finishing apparatus, said apparatus having a plurality of barrels rotatably supported between a pair of turret plates, the turret plates being rotated so rapidly by motor means that a powerful centrifugal force is created in the interior mass and the barrels being rotated by wheel means on the shafts of the turret plates and the barrels. In centrifugal barrel finishing, a mixture of a number of workpieces to be finished and a finishing medium are inserted into the interior of the barrels which are then rotated, the finishing such as polishing, coloring, crushing and mixing etc. being obtained by the workpieces rubbing against the interior surface of the barrel, against each other, and against particles and compounds of the finishing medium, which are also inserted into the interior of the barrels together with the workpieces.

Because of the powerful centrifugal force and rapid rotation, the centrifugal barrel finishing achieved an unmatched finishing efficiency, but it has a defect that time and hard labor are needed for loading, unloading and selecting the interior mass in using the machine, which reduces the advantage of unequalled improvement in finishing efficiency. For instance, usually the additional work, such as preparation, closing and opening the lids and after-treatments takes a longer time than the working time which is ten minutes at most. This work has required heavier human labor as the finishing efficiency of the machine has been improved.

However, according to the invention, all processes for centrifugal barrel finishing are automated in loading the workpieces and other materials, finishing operation and unloading processes. Since these operations are repeated by a sequence controller, working cycles are repeated more smoothly and rapidly, the workers are released from the heavy labor and the labor cost is reduced.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide an automatic centrifugal barrel finishing apparatus in which leading of the workpieces and other materials into the barrels and unloading of the finished workpieces with other materials are automated. In order to automate these processes effectively, the parts of the machine are moved by a sequence program previously scheduled.

After the finishing process, lids of the barrels are removed by a lid opening apparatus, the barrels are rotated about 180.degree. with the turrets fixed and with the openings of the barrels directed downwards, the mass is dropped out of the barrels by the action of gravity, the barrels are rotated reversely, unfinished workpieces and other materials are charged when the openings of the barrels are directed in an upward position, the lids are closed automatically, and charging and discharging of the mass are repeated with all finishing barrels. The finishing operation is started after unfinished mass is charged in all barrels and all lids are closed tightly. Accordingly, all machine elements such as an automatic opening and closing apparatus for barrel lids, a reversible rotating motor for the barrels, a charging apparatus for unfinished workpieces and other mass materials and a sieving apparatus for finished mass, are controlled by the sequence program. In order to follow the sequence program, limit switches and time relays are provided, and switches for subsquent processes is switched on when a contact of limit switch is pushed by a moving machine part or when a time relay works after a predetermined time interval.

A pneumatic, hydrodynamic, electrical and/or mechanical system can be used for the driving system of the apparatus according to the invention. However, the fundamentals of the invention are not changed by the specific driving system of the apparatus. This invention consists in that the driving parts of all machine elements are controlled by the sequence control system and that all parts are driven automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the apparatus according to the invention.

FIG. 2 is a side view of the same apparatus.

FIG. 3 is an elevation view of a positioning apparatus for the turrets.

FIG. 4 is a side view of an opening and closing apparatus for a barrel lid.

FIG. 5 is a front view of the same apparatus.

FIG. 6 is a front view of an apparatus for fixing and releasing a fastening shaft for the barrel lid.

FIG. 7 is a plan view of a barrel lid with fastening mechanisms.

FIG. 8 is a front view of a fixed barrel lid.

FIG. 9 is a front view of the barrel lid indicating the relative positions of the opening and closing mechanism, a lid, and a flange of the barrel, when the lid is opened and closed.

FIG. 10 is a front view of a lid holding apparatus when the lid is opened and closed.

FIG. 11 is a block diagram of the operations for the automatic machine according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention relates to an automatic centrifugal barrel finishing apparatus in which a plurality of barrels are rotatably fixed between a pair of turrets, charging and discharging of the workpieces and other materials are performed automatically, barrel lids are automatically opened and closed, barrels are reversibly rotated with the turrets fixed, and these operations are performed in due order determined by a sequence program using a sequence controller. The invention will now be further described by reference to the embodiment thereof illustrated in the accompanying drawings.

Frame 43 shown in FIGS. 1 and 2 is a skeleton structure made up of angle irons and plates including a horizontal main shaft 40 between a pair of bearings 41. On the main shaft 40 are fixed turrets 7 and 8 and a slow rotating wheel 9, and a driving wheel 11 for barrels is rotatably mounted on shaft 40. The turret 8 is cylindrical with one end being closed and the other end being open, and is secured to the main shaft 40 at the center of the end plate 8a, and the periphery of the turret 8 has grooves for transmission means, that is, belts or chains. End plate 8a also has a plurality of bearings 25 located at the equal angular intervals. Facing the bearings 25, bearings 25a, are fixed on the turret 7, and barrel shafts 4a are rotatably mounted between bearings 25 and 25a. On the centers of barrel shafts 4a, barrels 4 are fixed and driving wheels 24 for the barrels are also fixed at one of the ends of the shafts 4a. On the driving wheel 11 are as many driving wheels 23 as there are barrels, and in addition there are a wheel 22 for driving the wheel 11 and a brake drum 2 fixed on wheel 11. The number of barrels mounted between the turrets is arbitrary. However, since a machine with four barrels symmetrically arranged between the turrets is ordinarily used, there is described in the specification a machine having four barrels. It is necessary to mount the barrels symmetrically for balancing, because the machine is rotated at a high speed. At a corner of the base of the frame 43, a main motor 1 is mounted. The turret 8 is rotated by a belt 74 or other transmission means connected with a motor pulley 73 fixed on a motor shaft 72. The wheel 23 fixed on the driving wheel 11 and the wheels 24 fixed on the barrel shafts are connected by belts or chains 75 or other transmission means. Four positioning plates 12 are fixed on the periphery of the turret 7 as shown in FIG. 3. On the outside of each positioning plate 12, a recess 76 is provided, into which a roller 30 of a positioning apparatus can be fitted. Near the periphery of the brake drum 2 is positioned a brake shoe 5 which may be brought into contact with the brake drum 2 and may be separated from the brake drum 2. Brake shoe 5 is fixed at the end of a piston rod 77 of an air cylinder 3. By introducing compressed air to the piston side of the air cylinder 3, piston rod 77 advances, the brake shoe 5 presses against the periphery of the brake drum 2 and the rotation of the driving wheel 11 is prevented. Packings 6 and 26 are fixed on the open flange of the barrel and under the lid, respectively, as shown in FIG. 6, and contact of the two packings prevent leakage of finishing material from the barrel.

At the central part of the frame floow, an air cylinder 10 for slowly rotating the main shaft 40 is placed. The air cylinder 10 is double-acting, and a piston rod can be reciprocated by introducing compressed air on opposite sides of the piston, reciprocally. The end of the piston rod of the air cylinder 10 has a rack which meshes with a pinion 15. Pinion 15 has a shaft 16, which is used for slowly rotating shaft 40, and a slow rotating wheel 13 is fixed to the shaft 16. The wheels 9 and 13 are connected by chains or other transmission means. A one way clutch 14 is provided at the middle of the shaft 16. The clutch 14 transmits rotation to the main shaft 40, the direction of which is the same as the direction of rotation of the main motor 1.

A motor 19 is used for rotating barrels with the turrets fixed and the motor has a brake and is preferably reversibly rotatable. The motor 19 is mounted at a corner of the frame 43, the rotation of the motor 19 is transmitted to the wheel 22 by a motor shaft 79, a chain wheel 80 and a series of chains 81. Over the turret 7, a stopping apparutus is provided as shown in FIG. 3. A lever 29 of the bell crank type is rotatably pivoted to the piston rod 28 of the air cylinder 27, and at the other end of the lever 29, a roller 30 is provided. The roller 30 is so arranged that it is fitted into the recess 76 of the positioning plate 12 on the turret 7 when the piston rod 28 of the air cylinder 27 is moved backward to the position as shown by the solid lines in FIG. 3.

The lid opening and closing apparatus shown in FIGS. 4 and 5 consists of a supporting frame 32 rotatably pivoted to the supporting arm 33 provided at the upper part of the frame 43. An end of an air cylinder 31 is pivoted to the frame 43 and an end of a piston rod 82 of the same air cylinder 31 is rotatably connected to a side of the supporting frame 32. By the structure above-mentioned, by introducing compressed air to opposite sides of the piston of the air cylinder 31 reciprocally the piston rod 82 is caused to reciprocate and makes the supporting frame 32 rotate reciprocally as shown by the arrow 83 of FIG. 4. For instance, when the piston rod 82 is extended, the supporting frame 32 is moved to a position shown by dash-dot-lines in FIG. 4. This places the supporting frame 32 in a raised position and out of the path of the rotation of the turrets with the barrels. On the contrary, when the piston rod 82 is withdrawn into the air cylinder 31, the lid opening and closing apparatus stands upright and the lower end is facing a lid of a barrel. An air cylinder 35 is provided on the supporting frame 32, the lower end of the piston rod 36 of the same air cylinder 35 is provided with a lid opening and closing apparatus, and air cylinders 38 and 39 are positioned vertically on lower frame member 37 as shown in FIG. 5. The air cylinder 38 is used for chucking the lid 44 as will be described in connection with FIG. 10. The lower end of the piston rod 84 of the air cylinder 38 is rotatably pivoted to the an upper end of a connecting rod 51. The lower end of the connecting rod 51 is pivoted to an end of a chucking arm 52. The other end of the chucking arm 52 has a holding arm 85 which holds and fixes a shaft 60 for fixing the lid, cooperating with a guide piece 42 attached to the lower frame member 37. Upon introducing compressed air to the upper or lower side of the air cylinder 38, the piston rod of the air cylinder 38 is reciprocated and the holding arm 58 rotates about its axis 86 as shown by an arrow 87 in FIG. 10, and grasps or releases the shaft 60 which is attached to the lid.

The air cylinder 39 is used for locking or releasing the fastening mechanism of the lid. As shown in FIG. 6, the lower end of the piston rod 88 of the air cylinder 39 is rotatably connected with an end of a bell crank 55 by a pivot 89. The bell crank 55 is rotatably mounted on the lower frame 37 on a pivot 90. At the other end of the bell crank 55, a slot 91 is provided which fits slidably over a pin 57 fixed on a slider 56. The slider 56 can slide along a shaft 58 on the lower frame 37. A lever 59 is fixed on the slider 56 and the lower end of the lever 59 has a fork which embraces a slider 67 slidable on the lid fastening shaft 60. Reciprocation of the lever 59 reciprocates the slider 67 as shown by an arrow 92 in FIG. 6. At least one pair of fastening means is provided on the lid 44 and a longitudinal shaft 60 connects these fastening means as shown in FIG. 7. FIGS. 7-9 show an example of embodiment for opening and closing the lid automatically, having two pairs of the fastening means. Two pairs of supports 45 are fixed on both longitudinal sides of the lid 44 by bolts or welding. The support 45 has two holes, one of which has a pin 46 therein and the other of which has a pin 93 therein. Slots 50.1 and 50a.1 in one end of levers 50 and 50a respectively are rotatably and slidably fitted around the pin 46 fixed on the support 45. One end of a pair of other levers 47 is also rotatably mounted on the support 47 by the pin 93. The middle part of another lever 48 is pivoted rotatably on each of the levers 47 by a pin 94 as shown in FIGS. 8 and 9. On the pin 94 of the lever 48, springs 49 are provided. The ends 49a and 49b of the springs 49 engage the levers 47 and 48 so that the lower end of the lever 48 is given a torque to make the end 48 to rotate counterclockwise in the FIG. When the lid is closed, the lower ends 48a of the levers 48 are fixed against the flanges 4a of the lid 4 and the other ends 48b are engaged by the protrusions 50.2 and 50a.2 of the levers 50 and 50a. In this situation the lid is closed tightly as shown by the solid lines in FIGS. 8 and 9. The inner ends of the lever 50 fit between the forked ends 50a.3 of the lever 50a, and the shaft 60 extends through both lever 50 and ends 50a.3, as shown by FIG. 7. Washers 95 and 96 are fixed to the shaft 60 by pins 62 and 63. Between the levers 50, 50a and washers 95 and 96 are wound part of springs 64, the other ends 64a of the springs 64 being fixed to the pins 97 fixed on the side of levers 50 and 50a, and the springs 64 exert a torque to lift the shaft 60, in a direction to open the lid.

A collar 65 is fixed to the shaft 60, and slider 67 is slidably mounted on the shaft 60. A spring 66 is fixed between the collar 65 and slider 67, and exerts a force to press the extension 68 on slider 67 into a hole in the flange 69. The hole in the flange 69 is connected to an opening on the upper end of the flange 69, and the width of the opening is greater than the diameter of the shaft 60 and is smaller than the diameter of the extension 68 as shown in FIGS. 7 and 8. Therefore, when the extension 68 is pressed into the hole in the flange, the shaft 60 is fixed as shown in FIG. 8, and when the extension 68 is withdrawn from the hole, the shaft 60 can also be withdrawn through the opening and the levers 50 take a position as shown by the dot-dash-lines in FIG. 9.

As shown in FIG. 1, above a barrel at its feeding position, which means a barrel at the left side, a hopper 98 and selffeeding apparatus 99 are provided to feed a pre-determined amount of unfinished workpieces and other materials. The hopper 98 may be movable and be sheltered when the turrets are rotated. At the lower part of the frame 43, a selecting apparatus such as sieve means 71 with a vibrating motor or a magnetic separator, a conveyor and a drain are provided to separate finished workpieces from the mass. The finishing media can be returned to a reservoir by a conveyor, for instance.

A sequence control for the operations of the machine can be performed in various ways, for instance by a combination of relays and time switches, by a step-by-step program control, pin-board program control, punched cards, magnetic cards, punched tape or magnetic tape. In this specification, for example, using a step-by-step program controller (hereafter it is called "controller"), a signal sent from a limit switch or a time relay moves the contacts of the controller by one step, connecting in turn the contacts of the first to the n-th row. These contacts send an output signal to relays which operate motor switches and/or air valves for the individual operation.

The operations of the apparatus will now be described. After workpieces and other materials are fed into the interior of all barrels by the feeding apparatus 98, 99 described above, the lids are tightly closed, the lid opening and closing apparatus 32 is shifted to a position as shown in FIG. 1, then the contacts of the limit switch LS8 are closed by the piston rod 82, a signal is sent to the controller and the contacts of the controller are moved to the next step. By an output signal from the controller, compressed air is introduced into the piston side of the air cylinder 3, the brake shoe 5 is pressed on the drum 2 and the driving wheel 11 is breaked. This operation connects the contacts of a limit switch LS9 installed on the air cylinder 3, and sends a signal to the controller. An electric circuit of the main motor is connected by a relay, and the main motor 1 starts to rotate. The rotation of the motor is conveyed to the turret 8 by the pulleys and belts or other transmission devices, and is conveyed to the turret 7 by the main shaft 40. Then, the barrels are revolved about the main shaft 40. The barrels are also rotated about their own axes 4a, by a series of chains 75 or other transmission means connecting the driving wheels 23 and 24, the driving wheel 24 being fixed to the barrel axes 4a.

The workpieces in the barrel can be polished, and mixed by the revolution and rotation. It is necessary to increase the velocity of turret rotation until the acceleration caused by centrifugal force exerted on the workpieces exceeds the acceleration due to gravity in order to increase the finishing efficiency. Ordinarily, it is desirable that the acceleration caused by the centrifugal force exceeds by at least five times that due to gravity. The transmission means for revolution and rotation of the barrels can be performed any means, for instance, a series of chains, belts, silent chains, gears etc. can be used.

The ratio of the number of rotation of each barrel about its own axis to the number of revolutions about the main shaft is expressed by n/N, and n/N is determined by the ratio of the pitch circle diameter of the driving wheel 23 to that of the wheel 24 for barrels, and can be arbitrary values. When the ratio n/N is an integer, positive or negative, the relative position of each barrel to the frame is always the same if the barrels are stopped at a definite position. Especially, in the case of polishing, a hexagonal as shown in FIG. 1, pentagonal or octagonal cross-section for each barrel is chosen. If these cross-sections are chosen, sliding of the mass against the barrel wall does not occur, a sliding zone appears on the surface of the mass during finishing, the polishing is performed in the sliding zone, and good results can be obtained. In the case of grinding, a circular cross-section for the barrel is chosen, and grinding is performed at the interface of the mass and barrel wall where the sliding of the mass occurs. If a triangular or square cross-section is chosen, turbulent flow occurs in the mass which is effective for dull finish. Thus, the cross-section of the barrel must be chosen according to the object of the treatment.

After pre-determined finishing time elaspses, the main motor circuit is disconnected by a time switch, and one step is moved in the controller by a signal from the same time switch. Brake apparatus is operated which is not shown in the drawings, for instance, a band brake or electro-magnetic brake, and the turrets are stopped immediately. The duration of the operation of the brake is determined by a time switch. After a pre-determined brake operation duration and after the turrets stop or nearly stop, a signal from the time switch releases the brake action and actuates the air cylinder for slow rotation by the aid of the controller. The air cylinder 10 for slow rotation is double-acting and two limit switches are furnished at both extremities of the stroke of the piston rod 17 as shown in FIG. 2, and the contacts of these two limit switches are closed by the piston rod 17 which has the rack on it. Now, when the piston rod 17 is extended and the contacts are closed in the limit switch LS15, the air feed to the cylinder 10 is changed by an electro-magnetic valve, the compressed air is introduced to the rod side of the air cylinder 10 and the piston 17 recedes. When the contacts of LS16 are cut off by receding piston rod, the air feed is again changed, the compressed air is introduced to the piston side of the air cylinder 10 and the piston 17 again extends. The same procedures are repeated, the piston rod 17 reciprocates, the rack attached to the piston rod 17 rotates the pinion 15 and the pinion 15 rotates the shaft 16 reciprocally. Through the one way clutch 14 at the middle of the shaft 16 the rotation of the shaft 16 is delivered to the slow rotation wheel 13 and the slow rotation wheel 9 for the main shaft. The direction of rotation of the main shaft by the slow rotation wheel 13 coincides with that of the main motor. In other words, by repeated charge and discharge of compressed air to the air cylinder 10, slow rotation wheel 13 rotates the slow rotation wheel 9 on the main shaft slowly a small increment at a time, and also rotates the turrets with the barrels thereon slowly the same way.

The same signal of the controller which commences the slow rotation causes the compressed air to be introduced to the rod side of the air cylinder 27 as shown in FIGS. 1 and 3, the piston 28 is withdrawn as shown by the solid lines in FIG. 3, the roller 30 contacts the periphery of the turret 7 and the roller 30 drops into the recess 76 when the position of the roller 30 coincides with the positioning plate 12 on the periphery of the turret 7, because the turret rotates at a slow velocity. The protrusion 29a on the end of the lever 29 pushes the micro-switch LS1 buried in an elastic cushion 54, LS1 sends a signal to the controller, the controller sends a command to stop the compressed air to the pistons of the air cylinders 10 and 27, and the controller commands the following operation. When the roller 30 is in the recess 76, one of the barrels, i.e. the one at the nine o'clock position, is situated at a convenient position for discharging the mass as shown in FIG. 1, and the following three operations are performed.

The first is the approach of the chute 70 to the barrel, the second is the removal of the lid, and the third is the start of the vibrating conveyor 71. The approach of the chute 70 iss performed by introducing compressed air to an air cylinder (not shown in the figure) under the chute 70, the vibrating conveyor 71 is started by driving the vibrating conveyor motor (not shown in the figure) under the vibrating conveyor 71, and the removal of a lid is performed as will be described below.

When compressed air is introduced to the piston side of the air cylinder 31 as shown in FIGS. 1 and 4 by an output signal from the controller, the lid opening and closing apparatus situated in an inclined position out of the path of turret rotation as shown by the dash-dot-lines 37b in FIG. 4, is positioned as shown by the solid lines 35 and dotted lines 37a. When the apparatus is thus positioned, the end of the piston rod 82 pushes a limit switch LS2 as shown in FIG. 4 to send a signal to the controller, an output signal from the controller introduces compressed air to the piston side of the air cylinder 35 to extend the piston rod 36 and to lower the lower frame to a position indicated by the solid lines 37 in FIG. 4. During this movement, the lever 59 is fitted over the slider 67 as shown by the solid lines in FIG. 6. The end of the decent of the lower frame 37 is indicated by a limit switch LS3 on the lowest part of the apparatus 37 shown in FIG. 4 to send a signal to the controller, and an output signal of the controller stops the flow of compressed air to the air cylinder 35 and it sends compressed air to the rod side of the air cylinder 39. Then, the lever 59 moves to a position shown by the dash-dot-lines in FIG. 6, the extension 68 on the slider slides out of the flange 69 and the locking is released. The release is indicated by a limit switch LS5 at the apparatus 37 which sends a signal to the controller, an output signal from the controller sends compressed air to the rod side of the air cylinder 38 to lift the connecting rod 51 and to chuck the fastening shaft 60 attached to the lid by the chucking arm 52 as shown in FIG. 10. The chucking is indicated by a limit switch LS17 which sends a signal to the controller. An output signal of the controller send compressed air to the rod side of the air cylinder 35, to lift the shaft 36, to thereby lift the shaft 60 connecting levers 50 and 50a with the aid of springs 64, to rotate lower ends of the levers 48 to the outside as shown by the dash-dot-lines in FIG. 9, and the fastening of a lid is released. During further ascent of the piston rod 36, the lid is removed from the barrel, since the chucking apparatus holds the fastening shaft 60. The arms 53 prevent the vibration of the lid when it is lifted.

When the lid is lifted to a predetermined position, a protrusion on the piston rod 36 presses a limit switch LS6 at the lowest part of the air cylinder 35 to send a signal to the controller. An advance of a step in the controller sends an output signal to introduce compressed air to the rod side of the air cylinder 3 to release the brake shoe 5. A signal indicating the release issued by the limit switch LS9 installed at the upper part of the air cylinder 3 is sent to the controller. An output signal from the controller actuates a relay which starts to rotate the motor 19 for rotating barrels, and rotates the barrels at their positions without rotating the turrets. If the direction of rotation is counterclockwise in FIG. 1, then the contents of the barrel are dropped in the hopper 70 as the barrel rotates, and all the contents are discharged after the barrel rotates about 180.degree., and the opening of the barrel is directed downwards. An extension on the lid can press a limit switch LS10 on the hopper 70 to indicate the 180.degree. rotation of the barrels to send a signal to the controller and to stop the barrel rotation. Next, by a signal from a time switch, the barrels are rotated reversely after a definite time interval. In order to detect the return of the barrels, a limit switch LS11 is mounted on the hopper 98, and another extension on the lid presses LS11 to send a signal to the controller. In returning the barrel to the original upright position, it is not necessary to rotate the barrel reversely, but the barrel can be rotated in the same direction to a position for charging. If necessary, it is possible to stop the barrel at the position where the opening of barrel is not in the uppermost position but is slightly inclined in order to make charging easy.

An output signal from the controller introduces compressed air to the reverse side of the air cylinder to withdraw the chute 70. The completion of the withdrawal of the chute 70 can be indicated by a limit switch LS14. An interlocking circuit can be provided so that the main motor 1 is not operated if LS14 is not closed. A signal that the unfinished workpieces and other materials are charged advances the controller one step, which then send a signal which introduces compressed air to the piston side of the air cylinder 35 to lower the lid opening and closing apparatus which is now chucking a lid, to place the lid over the opening of the barrel, and to press the joint between levers 50 and 50a by the lower surface of the lower frame 37. By this action, the joint between the levers 50 and 50a is pressed to the position indicated by the solid lines in the direction as shown by an arrow 109 in FIG. 9. Then, the protrusion 50.2 and 50a.2 at the other ends of the levers 50 and 50a kick the ends 48b of the levers 48 from the positions shown by the dash-dot-lines to the positions shown by the solid lines as shown by an arrow 101 in FIG. 9 while compressing the springs 49, so that the lower ends 48a embrace the flanges 4a of the barrel 4 to close the lid tightly over the opening of the barrel. Since a protrusion 102 is provided on the lower side of the flange 4a, there is no problem of relative movement between the lever 48 and flange 4a and tightness of the lid is insured. At the same time as the lid closing operation takes place, lever 59 is fitted over the slider 67, while the fastening shaft 60 is being pressed, and the extension 68 on the slider 67 is opposite the hole in the flange 69. The limit switch LS3 operates again to send a signal to the controller, and an output signal of the controller ends the supply of compressed air to the air cylinder 39 so that the extension 68 on the slider 67 slides into the flange hole under the action of spring 66 to fix the fastening shaft 60 to the lid and to keep the lid in the closed condition. In the next stage, by the action of the same output signal and a time switch, compressed air which has been introduced to the rod side of the air cylinder 38 is released and compressed air is introduced to the piston side of the air cylinder 38, then the connecting rod 51 and chucking arm 85 are moved from the position shown by the solid lines to the position shown by the dash-dot-lines in FIG. 10 to release the chucking of the shaft 60. The release of chucking is signaled by a limit switch LS17 touched by a link between the piston rod 84 and the connecting rod 51. An output signal of the controller introduces compressed air to the rod side of the air cylinder 35 to pull up the piston rod 36 and the lid opening and closing apparatus.

When the lid opening and closing apparatus is raised to the position shown by the dash-dot-line in FIG. 4, the limit switch LS6 have contacts again to send a signal to the controller, to introduce compressed air to the piston side of the air cylinder 31, to make the piston rod 82 extend to the position as shown by the dash-dot-lines 82a in FIG. 4, make the apparatus 32 move to a position out of the path of the rotation of the turrets. At this position, the end of the piston rod 82a contacts the limit switch LS8 on the frame 43 to send a signal to the controller. An output signal of the controller introduces compressed air to the piston side of the air cylinder 27 to extend the piston rod 28, to move the lever 29 from the position shown by the solid lines to the position shown by the dash-dot-lines in FIG. 3, to release the turrets from the roller 30 and to press the limit switch LS12 on the frame 43 as shown in FIGS. 1 and 3.

By an output signal of the controller in response the signal from LS12, the turrets are again rotated slowly by the action of air cylinder 10 as described before and compressed air is introduced to the rod side of the air cylinder 27 as shown in FIGS. 1 and 3, after a slight delay of the start of slot rotation of the turrets by a time relay, to stop the turrets again by the engagement of the roller 30 in the next recess 76 of the next positioning plate 12 and in a position that the next barrel is in the proper position for discharging. The same procedures as described before, that is, stopping the supply of compressed air to the air cylinder 10, movement of the chute 70, opening of the lid 44, rotation of the barrels, and charging of the unfinished workpieces and other materials are repeated. Thus, the contents of all barrels are exchanged. A command of the controller, after a fourth signal from LS8 which indicates the shifting aside of the lid opening apparatus, introduces compressed air to the piston sides of the air cylinders 27 and 3 releases the turrets from the engagement by the roller 30 and to engages the brake drum 2 as shown in FIG. 1. The engagement of the brake drum 2 is indicated by LS9 to the controller. One step advance of the contacts of the controller starts the rotation of the main motor to commence the finishing operation. The selecting means may be worked during all operations, and if the selection can be finished in a short time the selecting means can be stopped by any command. This may be decided in considering the selecting time. Thus, after the finishing is performed in a pre-determined time, the main motor is stopped by a time switch. The operations are performed as described before. Accordingly, all operations can be automated without human labor. FIG. 11 is a block diagram of the operational sequence according to the invention. 103 is finish, 104 automatic stopping, 105 slow rotation of the main shaft, 106 stopping at a definite position of a barrel. 107 is automatic lid opening, 108 rotation of the barrels (discharging of the mass), 109 reverse rotation of the barrels, 110 charge of workpieces and other materials, 111 further reverse rotation of the barrels, 112 stopping of the barrels at a definite position, 113 automatic lid closing, 114 checking to see whether there is any barrel in which the mass is not yet exchanged.

Accordingly, by the invention, in using the centrifugal barrel finishing apparatus, all operations are programmed in a sequence controller, that is, the lids are opened automatically after finishing, barrels are rotated with the turrets fixed to direct the opening of the barrels downward, the finished mass is discharged from the barrel by the gravity, the barrels are reversely rotated to an upright position, a definite amount of unfinished workpieces and other materials are charged into the barrel and the lid is closed automatically, discharging and charging of each barrel are repeated as described above and the finishing operation is started again after all barrels are emptied of the finished mass and are charged with an unfinished mass. Therefore, the advantages are achieved in that all operations are automated, finishing efficiency is greatly increased and the workers may be relieved of heavy labors. Furthermore, since all automatic operations are repetitions of the same movements, the operations are performed steadily if the adjustment is made for one cycle and the construction of the control system can be simplified.

For full automation of the machine, many kinds of known stepping switchs, programmed controller and/or combinations of the limit switches, time switches and magnetic relays can used for the sequence control system, and known air cylinders, filters, automatic valves, oilers and pumps are used for the fluid system. In the structure described above, pneumatic power is used for the fluid system, but hydrodynamic pressure may be used.

While the invention has been illustrated and described in conjuction with a few preferred embodiments thereof, it is to be understood that numerous changes and modifications may be resorted to without departing from the spirit and the scope of the invention.

Claims

What is claimed is:

1. A centrifugal barrel finishing apparatus comprising, in combination, a pair of turrets mounted for rotation around a horizontal axis, a plurality of finishing barrels rotatably mounted between said turrets for rotation around axes parallel to said horizontal axis and spaced at intervals around said turrets, turret drive motor means coupled to said turrets for rotating said turrets, barrel rotating means coupled to said barrels for rotating said barrels relative to said turrets during rotation of said turrets, each of said barrels having a lid detachably connected to said barrel and removable from said barrel in a direction transversely of the axis of rotation of said barrel, lid grasping and removing means movably mounted on said apparatus for movement into and out of the path of rotation of said barrels as they are rotated on said turrets and having lid grasping and removing means movable toward and away from a barrel position in said path of rotation, moving means coupled to said lid grasping and removing means for moving said lid grasping and removing means, turret stopping means engageable with said turrets for stopping said turrets with a barrel in said barrel position, slow rotating means coupled to said turrets for slowly rotating said turrets, and barrel tipping means coupled to said barrel rotating means for actuating said barrel rotating means for tipping said barrels around the barrel axes when said turrets are stopped.

2. A centrifugal barrel finishing apparatus as claimed in claim 1 further comprising a sequence controller coupled to said turret drive motor means, said moving means, said lid grasping and removing means, said stopping means, said slow rotating means and said barrel tipping means for controlling said means in sequence to drive the turrets during the finishing operation, terminating the driving, slowly rotating the turrets, actuating the stopping means for stopping the turrets with a barrel in said barrel position, moving said lid grasping and removing means into the path of rotation and moving said lid grasping and removing means toward said barrel for grasping and removing the lid and then away from said barrel to remove the lid from the barrel, actuating said tipping means for tipping said barrel for discharging the contents of the barrel and then further tipping the barrel to a position for filling the barrel, and thereafter actuating the lid grasping and removing means in the opposite direction to replace the lid and to move away from the barrel, actuating the moving means for moving the lid grasping and removing means out of said path of rotation, and disengaging said stopping means, and repreating said operations for each of said plurality of barrels.

3. A centrifugal barrel finishing apparatus as claimed in claim 1 in which each lid includes clamping means for clamping the lid to the barrel and locking means coupled to said clamping means for locking the clamping means in the clamped position, and said lid grasping and removing means comprises lock actuating means for engaging and actuating said locking means when said lid grasping and removing means grasps said lid prior to removal thereof for unlocking said locking means, and when said lid grasping and removing means replaces said lid for actuating said locking means for locking said locking means prior to withdrawal of said lid grasping and removing means.

4. A centrifugal barrel finishing apparatus as claimed in claim 3 in which said clamping means includes a lever system and a shaft extending along said lid on which said lever system is mounted, said shaft being movable toward and away from said lid for actuating said lever system to clamp and unclamp said clamping means, and said locking means comprises a sleeve on said lid and an extension slidable on said shaft into and out of said sleeve, said shaft being locked in position close to said lid when said extension is in said sleeve and being free to move toward and away from said lid when said extension is out of said sleeve, and said lock actuating means comprises a member on said lid grasping and removing means for engaging said extension and moving it back and forth along said shaft.

5. A centrifugal barrel finishing apparatus as claimed in claim 4 in which said lid grasping and removing means comprises chucking means for grasping said shaft and moving it toward and away from said lid and lifting said lid from said barrel.

6. A centrifugal barrel finishing apparatus as claimed in claim 1 in which said lid grasping and removing means has one side pivotally mounted on said apparatus and has said moving means coupled to the other side thereof for pivoting said lid grasping and removing means around said pivotal mounting.

7. A centrifugal barrel finishing apparatus as claimed in claim 1 in which said turret stopping means comprises a plurality of plates on at least one of said turrets, one corresponding to each barrel, each plate having a recess therein, and a stop member movably mounted on said apparatus for movement into and out of said recess, and means coupled to said stop member urging said stop member toward said turrets in line with said plates for moving the stop member into a recess in a plate when a plate moves even with said stop member for stopping the turrets with a barrel in said barrel position.

8. A centrifugal barrel finishing apparatus as claimed in claim 1 in which said slow rotating means comprises a reciprocating drive member and a one-way clutch means coupled between said reciprocating drive member and said turrets for transmitting the movement of the drive member to the turrets as a series of incremental rotational movements in the same direction.

9. A centrifugal barrel finishing apparatus as claimed in claim 8 in which said turrets have a main shaft on which they are mounted, a belt means around said main shaft, and a belt drive shaft coupled between said belt means and said one-way clutch, and said reciprocating means comprises a rack and a gear, said gear being coupled to said one-way clutch, and a fluid pressure piston connected to said rack for reciprocating said rack.

10. A centrifugal barrel finishing apparatus as claimed in claim 1 in which said barrel rotating means comprises a drum on the horizontal axis of said turrets, a plurality of pulleys fixed on said drum, a pulley on each of said barrels on the axis thereof, belt means between the pulleys on the drum and the pulleys on the barrels, and brake means coupled to said drum for holding said drum fixed during driving of the turrets, whereby the barrels are rotated by the belt means, and said barrel tipping means comprises a barrel tipping motor coupled to said drum.

11. A centrifugal barrel finishing apparatus as claimed in claim 10 in which said barrel tipping motor is operable for rotating in one direction through 180.degree. and then in the opposite direction.

12. A centrifugal barrel finishing apparatus as claimed in claim 10 in which said barrel tipping motor is operable for rotation in one direction through 180.degree. and then for further rotation in the same direction through 180.degree..

13. A centrifugal barrel finishing apparatus as claimed in claim 1 further comprising a hopper for receiving the contents of the barrels, said hopper being mounted on said apparatus for movement into and out of the path of rotation of said barrels at a position beneath a barrel in said barrel position, and means coupled to said hopper for moving said hopper.