US20020106981A1

US20020106981A1 - Double moving column grinder with simultaneous two wheel grinding

Info

Publication number: US20020106981A1
Application number: US10/113,760
Authority: US
Inventors: Salvador Aznal
Original assignee: Individual
Current assignee: Danobat SCL
Priority date: 2000-04-07
Filing date: 2002-03-29
Publication date: 2002-08-08

Abstract

A grinding machine for grinding bulky workpieces of considerable length, such as frames, columns and tables of machine tools. Said grinding machine comprises at least one machining table on which a workpiece to be ground is placed, at least two columns linked to a single carriage, said carriage moving longitudinally over a base parallel to said machining table, and at least one wheelhead affixed to each of said columns, each one of said wheelheads comprising its own independently operated vertical and transverse drive means and at least one of said wheelheads being capable of angle movement. So, said wheelheads have a common longitudinal movement and independent vertical and transverse movements, so that said wheelheads can work simultaneously.

Description

The present invention is a Continuation-In-Part (CIP) of the originally filed U.S. patent application Ser. No. 09/816,604.[0001]

TECHNICAL FIELD

The present invention relates to machines for grinding workpieces, and more specifically to machines for grinding such workpieces as frames, columns and tables of machine tools.

PRIOR ART

The grinding of bulky workpieces of considerable length such as frames, columns and tables of machine tools requires the use of two different types of wheelheads: tangential wheelheads and angle-movement wheelheads (so-called universal wheelheads).

The use of conventional flat grinders with a single column for grinding workpieces of this type is well known. For this purpose, besides using the wheelhead mounted on the grinding machine column, another carriage with another wheelhead is fitted to the side of said column, said additional wheelhead generally having angle movement. The machining table moves in relation to the column during the grinding process. This kind of grinding machines cannot work with both wheels simultaneously.

The use of bridge grinders for grinding workpieces of this type is also well known. Bridge grinders are grinding machines with two opposing columns, one on either side of a machining table, and linked transversely by a cross rail. Two wheelheads are mounted on said cross rail, each of said wheelheads having its own vertical drive means and its own transverse drives means (up to a limited travel), and one of said wheelheads generally being capable of angle movement. The cross rail may be fixed or vertically movable. During the grinding process, the machining table moves in respect of the columns and the cross rail. This kind of machines cannot work with both wheelheads simultaneously, as, although said wheelheads have their own drive means, the actual machine frame with the cross rail prevents the wheelheads from working at the same time because they would have to cross over as the transverse movement of both wheelheads is effected on a single support bracket.

DISCLOSURE OF THE INVENTION

The object of the invention is to provide a grinder for grinding bulky workpieces of considerable length, such as frames, columns and tables of machine tools.

The grinding machine of the invention comprises at least one machining table on which a workpiece to be ground is placed, at least two columns linked to a single carriage, said carriage moving longitudinally over a base parallel to said machining table, and at least one wheelhead affixed to each of said columns, each one of said wheelheads comprising its own independently operated vertical and transverse drive means and at least one of said wheelheads being capable of angle movement. So, said wheelheads have a common longitudinal movement and independent vertical and transverse movements, so that said wheelheads can work simultaneously.

As both wheelheads work simultaneously, output is practically doubled. In fact, the total grinding time is the grinding time of the wheelhead that has the longer process, as the grinding time of the other wheelhead is included in the grinding time of the wheelhead that has the longer process.

Since it is the columns that move and the wheelheads have all their movements in relation to said columns, the grinding machine can grind workpieces placed on different aligned machining tables consecutively. Thus, the machine can be grinding the workpiece of one machining table, while the operator handles the workpiece of another table. In this way, the workpiece change time is nil.

On the other hand, taking into account the automatic workpiece change, the space occupied by the machine is smaller than that of a bridge machine and even less than a conventional grinding machine, as the latter requires palletizing systems. Moreover, there is a considerable saving in costs especially in relation to the use of a bridge machine. These and other advantages will become apparent in the detailed description of an embodiment of the invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of an embodiment of the machine of the invention. [0011]
FIG. 2 is a profile view of the embodiment of FIG. 1 according to section II-II. [0012]
FIG. 3 is a profile view of the embodiment of FIG. 1 according to section III-III. [0013]
FIG. 4 is a profile detailed view of the carriage and the base of the embodiment of FIG. 1. [0014]

DETAILED DISCLOSURE OF THE INVENTION

In the embodiment of FIGS. [0015] 1 to 4, the grinding machine 1 comprises a machining table 11 on which a workpiece 12 to be ground is placed, two columns 2 and 3 linked to a single carriage 8, said carriage 8 moving longitudinally over a base 9 parallel to said machining table 11, and one wheelhead 4 provided with a grinding wheel 6 and affixed to column 2 and one wheelhead 5 provided with a grinding wheel 7 and affixed to column 3. The wheelhead 5 has vertical drive means 50 (shown in FIGS. 1 and 3) and horizontal drive means 51 (shown in FIG. 3). The wheelhead 4 has vertical drive means 40 (shown in FIGS. 1 and 2) and horizontal drive means (not shown for clarity). The vertical drive means 50 and the horizontal drive means 51 of wheelhead 5 are operated independently of the vertical drive means 40 and the horizontal drive means of wheelhead 4, an vice versa.
So, the [0016] wheelheads 4 and 5 have a common longitudinal movement according to a direction A (shown in FIG. 1), and independent vertical and transverse movements, so that said wheelheads 4 and 5 can work simultaneously: the wheelhead 4 has a movement according to a direction B and a movement according to a direction C (shown in FIG. 2), and the wheelhead 5 has a movement according to a direction D and a movement according to a direction E (shown in FIG. 3).
The [0017] wheelhead 5 only has tangential movement. The movements that said wheelhead 5 has in relation to the column 3 are the usual ones possessed by the wheelheads on flat surface grinding machines. FIG. 3 shows the wheelhead 5 in three different positions. The wheelhead 4 is capable of being moved also in an angular direction, which permits the grinding of workpieces of widely varying shapes. Said wheelhead 4 is a so-called universal wheelhead and has all the movements possessed by wheelheads of this type. Angular movement of said wheelhead 4 is provided by a rotary plate 4 a. FIG. 2 shows the wheelhead 4 in three different positions. The columns 4 and 5, and consequently the wheelheads 4 and 5, are facing each other.
The workpieces to be ground are bulky items of considerable length, not usually more than one meter wide, such as frames, columns and tables of machine tools. The grinding [0018] wheels 4 and 5 are large diameter wheels (up to 600 mm) and have high-power servomotors. The grinding with both wheels is carried out at the same time with a single numeric control that works in two channels with specific software.
The movement of the [0019] carriage 8 over the base 9 is effected by means of a hydrostatic slideway 90, so as to be able to reach typical conventional grinding speeds (30 m/min). With reference to FIG. 4, said hydrostatic slideway 90 includes longitudinal guides 91 on which the carriage 8 slides, said guides 91 having chambers 17 with oil under pressure for lubrication. With said oil under pressure the necessary rigidity of machine 1 is achieved.
The [0020] hydrostatic slideway 90 enables considerable accelerations and decelerations to be achieved and, furthermore, it ensures that the movement of the columns is uniform, thus preventing the appearance of a buckling effect in said columns. In the embodiment of FIG. 1 columns 2 and 3 are linked at the top by means of a cross member 10 to prevent said buckling effect. With the use of the hydrostatic slideway 90, said cross member 10 is not necessary.
The longitudinal movement of the [0021] carriage 8 is governed by means of a rack and pinion system. With reference to FIG. 4 again, a pinion 13 is mounted on the axis of a reducer 16 that is fixed to the carriage 8. Said reducer 16 is actuated by a servomotor not shown). Said pinion 13 is geared to a rack 14 that is fixed to the base 9. The servomotor turns the reducer 16 and the rotary movement of said reducer 16 is converted into linear movement of the carriage 8 by means of the pinion 13 and the rack 14. An encoder placed in the servomotor controls the location of the carriage 8.
As the assembly formed by [0022] carriage 8, columns 2 and 3 and their respective wheelheads 4 and 5 move en bloc on base 9, it is possible to install various aligned machining tables 11, each with its respective workpiece 12, along the whole length of the base 9 and parallel to said base 9. This means that the machine 1 may be grinding workpiece 12 of one machining table 11, while the operator is handling the workpiece 12 of another machining table 11.

Claims

What is claimed is:

1. A grinding machine for grinding bulky workpieces of considerable length, such as frames, columns and tables of machine tools, comprising:

at least one machining table on which a workpiece to be ground is placed;

at least two columns linked to a single carriage, said carriage moving longitudinally over a base parallel to said machining table; and

at least one wheelhead affixed to each of said columns, each one of said wheelheads comprising its own independently operated vertical and transverse drive means and at least one of said wheelheads being capable of angle movement;

thereby said wheelheads having a common longitudinal movement and independent vertical and transverse movements, so that said wheelheads can work simultaneously.

2. The grinding machine of claim 1, wherein said columns are facing each other.

3. The grinding machine of claim 1, wherein the movement of said carriage over the base is effected by means of a hydrostatic slideway.

4. The grinding machine of claim 1, wherein the longitudinal movement of the carriage is governed by means of a rack and pinion system.