Polishing Machine Or The Like With A Removable Platen

Abstract

A polishing machine or similar abrading apparatus including a horizontally mounted platen and at least one work support head to locate workpieces on the platen for relative movement therewith. The platen includes a detachable connection, and a hoist mechanism is provided to remove the platen for changing polishing pads or similar operations.

Description

Cross-reference is made to coopending application Ser. No. 862,219 and now U.S. Pat. No. 3,611,654 dated Oct. 10, 1971, entitled "Polishing Machine or Similar Abrading Apparatus", filed on even date herewith in the names of John L. Weber and Carl J. Vella.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to abrading apparatus such as polishing or lapping machines, and more particularly to such machines having rotating platens that treat workpiece surfaces.

2. Description of the Prior Art

Polishing or lapping machines of this general class are known. These machines comprise a frame in which is mounted a horizontally disposed platen that rotates about a vertical axis. The upper surface of the platen, on which one or more workpieces are placed, acts as the operating surface to abrade the engaging surfaces of the workpieces by relative motion. Usually, the machines also include work support means such as a ring within which the workpieces are located to hold the workpieces in place. The support means may also apply a load to the workpieces to increase the working surface pressure to a desired operating level.

Machines of this class are sizable since typically the platens may be in the range of two or more feet in diameter, and the operators stand to feed the machines or perform other functions. Between operating cycles, work with such machines is very inconvenient, and the operator must assume uncomfortable positions and will usually require assistance to perform functions such as cleaning the platen or replacing a polishing pad on the platen. This necessarily increases downtime to levels that are less than satisfactory.

SUMMARY OF THE INVENTION

The present invention overcomes many of the disadvantages of prior machines of this class by providing a platen with a detachable connection and including a mechanism to remove the platen to a convenient work area. To reduce downtime even more, substitute platens may be readied as replacements so that between-cycle operations can be performed off-line. In a preferred form, the removing mechanism comprises a hoist to lift the platen, with the hoist mounted in a movable carriage to move the platen to one side of the machine.

BRIEF DESCRIPTION OF THE DRAWING

The invention and its features, as well as objects and advantages thereof, will become more apparent in the course of the following description of a preferred embodiment, reference being made to the accompanying drawing forming a part thereof and wherein:

FIG. 1 is a partial perspective view of a polishing machine suitably incorporating the present invention in its preferred form;

FIG. 2 is a side view of the machine of FIG. 1, showing the platen in solid line position as being removed;

FIG. 3 is a partial cross sectional view taken through the platen and portions of the machine frame; and

FIG. 4 is a partial cross sectional view of the hoist mechanism located above the platen.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, a suitable apparatus incorporating the present invention comprises a surface polishing machine having a frame 10 with a work table 11 approximately waist high to an operator. Table 11 defines a central annular opening 12 within which is located a horizontal platen assembly 13 that is rotatable about a central vertical axis by a known rotating motor drive mechanism located within the frame 10 below the platen assembly 13. Supported by the frame 10 by a hollow column 14 and above the work table 11 is a control head unit 15. Mounted on the control unit 15 are suitable imput controls such as work area cooling water valves 16, operating buttons such as an abrasive slurry feed pump control button 17 and drive motor stop and start buttons 18, 19, a timing device 20 with a reset button 21, and pneumatic controls 22 (two located on the other side of the control unit 15) for selectively raising and lowering work support heads 25 on pistons 26 in a known manner. Each work support head is weighted in a predetermined manner to apply equalized pressure to one or more flat workpieces located on the platen assembly 13 when the heads 25 are lowered. As shown loading is accomplished by placing the workpieces on the platen assembly 13 below a head 25 while the platen is stopped. When the heads 25 are lowered, a collar 28 constrains movement of the workpieces 27 (see FIG. 3) while the platen assembly rotates. When the heads 25 are lowered, the collars 28 respectively are frictionally engagable with one of three peripheral idler wheels 29 on stationary supports 30 and a central idler wheel 32 mounted on a center post 33 forming part of the platen assembly. By frictionally engaging all three collars, movement of the platen is translated through the workpieces and the pulleys to the collars 28 to rotate the collars uniformly so that all workpieces 27 describe a uniform plantary motion on the platen surface.

During operation, a known abrasive or polishing compound in slurry form is fed from a reservoir 35 supported by a table 38 at the rear of the frame 10, and any known suitable pump system for conveying the polishing slurry from reservoir 35 to the platen area by three flexible feed tubes 38 may be used.

Referring now to FIG. 3, the platen assembly 13 includes a hollow shaft 40 which is connected to a drive motor (not shown) below the assembly. A circular bowl-shaped platen support member 41 is fixed to the flanged end 42 of shaft 40 by suitable bolts 43. Mounted on top of the platen support member 41 is a platen disc 45 which is removably attached to the support member 41 by a plurality (e.g. three) of set screws 47 in corresponding bosses 48 on the platen disc 45 engaging a peripheral groove 49 in the platen support member. An enclosed space 50 defined by the platen disc 45 and platten support member 41 forms a chamber into which a cooling fluid such as water may be pumped through the hollow shaft 40.

Located around the periphery of the platen assembly 13 is an annular drain pan 54 to receive excess polishing slurry and other waste for removal by drain openings 55 through a suitable drain line (not shown). On the top surface of the platen disc 45 is a polishing pad 56 that is held by an adhesive and may be peeled off for changing.

The center post 33 which supports the central idler 32 by a bearing support is in turn fixed to the platen disc 45 for movement therewith by suitable means such as stud 58. Each outer idler support 30 is pivotally connected to a column 59 fixed to the frame 10. Thus, during normal operation each idler 29 partially overlies platen disc 45 but may be pivoted out of the way when the equipment is not in operation or when it is desired to remove the platen 45 according to the invention. For removal, the center post 33 further includes a pair of laterally extending pins 61 which are engagable by the hook end 62 of the hoisting mechanism to be described.

In the preferred form, the hoisting mechanism as shown in FIG. 4 comprises a link chain 65 to which the hook 62 is attached at its free end. The other end of the chain is attached to a cog 66 rotatably supported about a horizontal axis on an axle 67 in the control head 15. The chain 65 and cog 66 are configured such that the chain wraps around the cog as the hook end is raised. Axle 67 is rotatably supported at its ends by a pair of vertical plates 68 (one shown) forming part of a translating carriage. The carriage may be of the equipment drawer type in which the center portion 70 is supported for movement to the left by ball bearings by an intermediate moveable portion 71. Intermediate portion 71 in turn is similarly supported to a fixed portion 72 by ball bearing assemblies. Only one side of the carriage is shown, with a cog and shaft assembly 69 connected to the center portion 70 on both sides to provide the change in the chain direction of movement.

Coaxial with the chain cog 66 on the axle 67 is a spur gear 74 meshing with a worm gear 75 rotatably mounted in bearings fixed to upper and lower arms 76 connecting plates 68. The lower end of the worm gear includes a hand crank 78 accessible from below to raise (or lower) the hook 62 by rotating gear 74 to wrap (or unwrap) the chain 65 around the chain cog 66. A face plate 79 is fixed to the front ends of the plates 68 to enclose the front of the hoist mechanism. To store the hook end 62 when not in use, a V-bracket 81 also is fixed by its leg ends to both sides of center carriage portion 70 with the hook 62 resting on the connecting leg as shown in dotted lines.

Whenever it is desired to remove the platen disc 45 between operations, as for example to change the polishing pad 56, all the heads 25 are raised and flexible tubes 38 lifted. The set screws 47 holding the disc 45 to support member 41 are unscrewed to release the platen disc from the support member, and idlers 29 are moved out of the way. Hook end 62 is removed from bracket 81 and lowered by turning handcrank 78 until the hook can be engaged with the pins 61 on the center post 33. The crank 78 is then turned in the opposite direction to wrap the chain around the cog 66 and raise the platen disc to a level above the work table 11. The carriage is then pulled forward to move the platen 45 to an easily accessible location in front of the machine. FIG. 2 shows the platen in the raised position and partially forward for removal of the pad. To reduce downtime even more extra platens 45 may be prepared with fresh pads and made available for substitution with the used platen disc. The new platen is attached to the hook 62, and the carriage is then returned to the closed position and the platen lowered. The screws 47 are tightened to fix the platen 45 to support 41, and the idlers 29 moved back into operating position. After unpolished workpieces 27 are placed on the platen, the support heads 25 can then be lowered for further operation of the equipment.

Further features of a polishing machine in its preferred form are described in copending application Ser. No. 862,219 entitled "Polishing Machine or Similar Abrading Apparatus" filed on even date herewith in the names of John L. Weber and Carl J. Vella.

Thus it can be seen that the present invention provides an economical and convenient means for changeover between operating cycles to substantially reduce downtime and lost production. Operators are not required to work in cramped areas, and standby platens may be provided to permit off-line preparation while the equipment is in operation.

While the present invention has been described with reference to a preferred embodiment as shown and described, it is obvious that changes, for example in size, shape, design or arrangement of parts, may be made without departing from the spirit of the invention.

Claims

We claim:

1. In an abrading machine, the combination comprising a frame; a platen assembly horizontally disposed in said frame for rotation about a vertical axis and including a platen to receive on its upper surface workpieces to be abraded, a platen support member below the platen and means for detachably connecting the platen to the platen support member; a control head supported by the frame and above the platen, the control head including at least one work support head above the platen, the work support head being movable between a first position constraining workpieces on the platen and a second position spaced from the platen; and hoisting means in said control head and connectable with said platen for removing the platen from the platen support member when the work support head is in the second position, the hoisting means comprising a mechanism to lift and translate the platen to a location outward of the frame.

2. The combination according to claim 1 wherein said lifting and translating mechanism comprises cranking means for raising and lowering the platen and a slidable carriage to translate the platen radially with respect to the vertical axis and frame.

3. The combination according to claim 2 wherein the platen comprises a central post on said axis, one of said hoisting mechanism and said post comprising a pin member and the other comprising a hook member engagable with the pin member to detachably connect the hoisting mechanism to the platen.

4. The combination according to claim 1 wherein the translating mechanism comprises a slidable carriage located in said head.

5. The combination according to claim 3 wherein the hoisting mechanism includes said hook member and the carriage comprises bracket means for storing the hook member when not in use.

6. The combination according to claim 2 wherein the cranking means comprises a rotatable cog, a link chain connected at one end to said cog and connectable at other end to said platen, and an accessible hand crank for selectively wrapping and unwrapping the chain around the cog to raise and lower the platen.

7. Abrading apparatus comprising a frame including a head; a horizontally disposed platen assembly within the frame and rotatable about a vertical axis in the frame, the platen assembly including a platen which supports work pieces to be abraded, a platen support member and means for detachably securing the platen to the platen support member; at least one work support member located on the head above the platen and alternately raised and lowered to constrain movement of work pieces on the platen for relative movement therewith to abrade the work pieces; a center post on the platen, and a hoisting mechanism in the head, the hoisting mechanism comprising a translatable carriage movable from a closed position within the head to an open position extended in front of the head, hooking means detachably connectable to the center post, and a crank assembly and a linkage connecting the crank assembly to the hooking means, the crank assembly selectively raising and lowering the detached platen with respect to said platen support member and the carriage selectively movable to remove the platen laterally with respect to said frame.

8. The apparatus according to claim 7 wherein the crank assembly is attached to the moveable carriage.