US3543443A - Machine for grinding large-area workpieces - Google Patents

Machine for grinding large-area workpieces Download PDF

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US3543443A
US3543443A US682270A US3543443DA US3543443A US 3543443 A US3543443 A US 3543443A US 682270 A US682270 A US 682270A US 3543443D A US3543443D A US 3543443DA US 3543443 A US3543443 A US 3543443A
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grinding
workpieces
machine
belt
pressure beam
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Karl Heesemann
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B21/00Machines or devices using grinding or polishing belts; Accessories therefor
    • B24B21/04Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces
    • B24B21/10Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces involving a rigid member, e.g. pressure bar, table, pressing or supporting the belt over substantially its whole span
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B21/00Machines or devices using grinding or polishing belts; Accessories therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B21/00Machines or devices using grinding or polishing belts; Accessories therefor
    • B24B21/04Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces
    • B24B21/06Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces involving members with limited contact area pressing the belt against the work, e.g. shoes sweeping across the whole area to be ground
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B21/00Machines or devices using grinding or polishing belts; Accessories therefor
    • B24B21/04Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces
    • B24B21/06Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces involving members with limited contact area pressing the belt against the work, e.g. shoes sweeping across the whole area to be ground
    • B24B21/08Pressure shoes; Pressure members, e.g. backing belts

Definitions

  • the fine and very fine grinding of veneered, lacquered or otherwise laminated and also of solid workpieces having large surface areas is executed at present in a known and advantageous manner by cross grinding on two separate automatic belt-grinding machines.
  • cross grinding yields the best grinding quality.
  • the pre-grinding is carried out as a transverse grinding, i.e. across the grain, and the finishgrinding as a longitudinal grinding, i.e. parallel to the grain.
  • the grinding belt is always only worn out in the area which corresponds to the workpieces being ground.
  • the grinding belt subsequently clogs on these longitudinal 3,543,443 Patented Dec. 1, 1970 SUMMARY OF THE INVENTION It is the object of the present invention to avoid the disadvantages mentioned above and to provide an eflicient method of cross grinding large-area workpieces, and a machine for carrying out that method; which method comprises the steps of first grinding the workpieces transverse to their direction of feed, and subsequently grinding the workpieces substantially parallel to said direction of feed.
  • An important feature of the invention consists in that transverse grinding motions may be carried out when grinding the workpeces substantially parallel to their direction of feed.
  • the machine for carrying out the method comprises two supports, rails connecting said supports, a drive roller and an idler roller supported by said supports, a conveyor belt led around said rollers for feeding workpieces to be ground and moving preferably in one and the same direction, at least one transverse grinding mechanism mounted on one of said rails, a longitudinal grinding mechanism arranged downstream of the transverse grinding mechanism, and means for moving said longitudinal grinding mechanism to and fro relative to the workpieces passing through.
  • transverse grinding mechanisms are arranged one behind the other and are each provided with a resilient pressure beam and an endless laminated pressure belt inserted between the grinding belt of the transverse grinding mechanism and said pressure beam.
  • the longitudinal grinding mechanism is preferably pro vided with a to-and-fro movable, advantageously endless grinding belt pressed against the workpieces to be ground by a pressure beam pressing against its inner side, while the grinding belt is equipped with a device to adjust it to run in the center of its drive and guide roller.
  • the grinding belt drive and the guiding members as well as, if necessary, the pressure beam with its holding mechanism are mounted on a guide member movable transverse to the direction of travel of the workpieces.
  • a device such as a spindle may be provided.
  • Another embodiment of the invention is possible wherein not the whole longitudinal grinding belt mechanism, but only its grinding belt is moved to and fro transverse to the direction of travel of the workpieces by a special controlling means.
  • the machine proposed by the invention excels in that the traces of the grinding are in an advantageous manner compensated while the workpiece runs through the machine in one and the same direction.
  • FIG. 1 is a schematic side view of a cross grinding machine according to the invention
  • FIG. 2 is a cross section on the line 11-11 of FIG. 1;
  • FIG. 3 is a cross section through the guide member of the machine with an enclosing traverse and the grinding belt;
  • FIG. 4 is a front view, partly in cross section, of the pressure beam of the cross grinding machine
  • FIG. is a cross section on the line VV of FIG. 4
  • FIG. 6 is a cross section on the line VIVI of FIG. 4.
  • FIGS.1 and 2 show a cross belt grinding machine 10 mounted on two supports 11 and 12 connected by two lower connecting rails 13 and 14.
  • An endless conveyor belt 15 for feeding workpieces 52a is led around a drive roller 15b and an idler roller 15a.
  • a motor (not shown) drives the drive roller 15b and thus the conveyor belt 15 through an infinitely variable gear unit in preferably one and the same direction.
  • two transverse grinding mechanisms 7 and 18 are fixed at a distance from one another on an upper connecting rail 16 extending between the supports 11 and 12 and are provided with two vertically adjustable pressure beams. It is self-evident that instead of two, also one or more than two tranverse grinding mechanisms may be provided which in the latter case are arranged one behind the other.
  • Pressure rollers 19, and 21, 22 which may each be composed of many small rollers are arranged on each side of the two pressure beams of the two transverse grinding mechanisms 17 and 18 respectively.
  • a contact roller is arranged in the same plane as the pressure rollers 19 and 21 and is actuated by the passing workpiece 52a to control the vertical movements of the pressure beams.
  • the pressure beams are provided with mechanisms (not shown) with which the working width can be adjusted according to the width of the workpieces 52a passing through the machine.
  • an endless laminated pressure belt (not shown) may be inserted between the grinding belt and the pressure beam of the transverse grinding mechanisms 17 and 18.
  • a longitudinal grinding mechanism 23 with a pressure beam 23a is arranged downstream of the two transverse grinding mechanisms 17 and 18.
  • This longitudinal grinding mechanism 23 is designed as a wide belt grinding machine and comprises a fixed box-shaped guide member 24 which is mounted at one of its ends through the intermediary of a carrier arm 25 on the support 11 and is braced at its other end against the support 12 by a pivotable support 26.
  • the connection between the pivotable support 26 and the support 12 can be disengaged, for example, when the grinding belt must be replaced, by means of a locking device like a locking lever 26a.
  • a drive roller 32 for a wide endless grinding belt 34 is driven by a motor 32a and rotatably mounted on an arbor 37 extending between the upper ends of the end plates 28 and 29.
  • This wide endless grinding belt 34 is led around this drive roller 32 and lower guide rollers 35 and 36 located downstream and upstream of the pressure beam 23a.
  • the grinding belt 34 is tensioned by means of a compressed air cylinder 38 with a piston rod 38a through parallel rods 39.
  • This air cylinder 38 is mounted on the traverse 30.
  • an electropneumatic control device which comprises for example a compressed air cylinder 40 is provided, through the intermediary of which the arbor 37 of the drive roller 32 is moved about a universal joint 41 or the like when one of the edges of grinding belt 34 touches one of lateral limit switches (not shown) located in the immediate vicinity of the edges of the grinding belt 34.
  • the traverse 30 with the end plates 28 and 29 and the further parts of the longitudinal grinding machine 23 connected thereto are movable on the guide member 24 by a reversible motor 42 connected to a spindle 43 passing through a spindle nut 44 built into the end plate 29.
  • the to-and-fro motions produced by the reversible motor 42 of the above-mentioned parts of the longitudinal grinding mechanism 23 are limited by limit switches 45 and 46 which effect the reversal of the motor 42 whenever these moving parts reach an end position.
  • the extent of the to-and-fro motions is adjustable by displacing the limit switch 45 on a rail 47.
  • the pressure beam 23a is vertically adjustable in the end plates 28 and 29 by means of a parallel linkage system 48.
  • Pressure rollers 49 and 50 which may consist of a plurality of small rollers, are provided downstream and upstream of the guide rollers 35 and 36 for the grinding belt 34 to guide the workpieces 52a on the conveyor belt 15.
  • a contact roller (not shown) is arranged in the same plane as the pressure roller or rollers 50 and is activated by the passing workpieces 52a automatically to control the upwards and downwards motions of the pressure beam 23a acted upon by a compressed air cylinder 51, its piston rod 51a and a shaft 5111 (FIG. 5).
  • clamping collars 51g are fixed on the shaft 51b mounted in mountings 510 which collars 51g carry the pressure beam 23a at its ends through the intermediary of levers 51d and 51e with a carrier foot 51 As the shaft 51b turns, the pressure beam 23a lowers or raises.
  • This adjustment mechanism comprises a device for pre-adjustment according to the width of the passing-through workpieces 52a as well as an automatically working mechanism which are both dependent on contact roller control and reverse motions for adapting the pressure surface of the pressure beam 23a to the workpieces 52a guided by a guide bar 52.
  • the guide member 24 is closed at its free end by an end plate 53 (FIG. 2) on the upper end of WhlCh the reversible motor 42 and the spindle 43 are located.
  • the lower end of this end plate 53 is provided with a vertical guiding device 54 (FIG. 4) in which one end of a guide rail 55 is guided so as to be unshiftable in its axial direction, whereas its other end rests in another vertical guiding device 56 arranged on the carrier arm 25.
  • the vertical guiding devices 54 and 56 permit the guide rail 55 extending through the pressure beam 23a to move up and down with the same.
  • the pressure beam 23a can move to-and-fro transverse to the direction the workpieces 52a are fed through the machine.
  • the guide rail 55 in the pressure beam 23a is guided in a suitable way, for example by ball bearings and rollers 55a (FIG. 5 which are adapted to the particular profiling of the guide rail 55.
  • sliding rails 57 and 58 are guided to be movable and lockable in the guide rail 55, which sliding rails 57 and 58 are provided with oblique surfaces 57a and 5812 at the ends pointing towards one another.
  • these oblique surfaces 57a and 58a extend adjacent both longitudinal edges of the workpieces 52a passing through the machine and their slope corresponds to the necessary slight slope of the lower pressure surface of the pressure beam 23a constructed as a steel plate 65.
  • the sliding rail 58 is provided with holes 59 in which a lock pin 60 engages according to the width of the workpieces 52a passing through the machine, which lock pin 60 is passed on boht sides of the sliding rail 58 through a fork-shaped member 61 on the guide rail 55.
  • the steel plate 65 is carried by the lower ends of lifting rods 66 and 67 fixed intermediate the two longitudinal edges of the steel plate 65.
  • the upper ends of the lifting rods 66 and 67 are screwed into pivoting levers 68 and 69 fixed as well as a pivoting lever 70 on a common shaft 73 rotatably mounted in bearing blocks 71 and 72.
  • the pivoting lever 70 On its free end the pivoting lever 70 carries a roller 74 which rolls on the sliding rails 57 and 58, respectively, during the to-and-fro motions of the pressure beam 23a.
  • the sliding rail 58 can be so adjusted that the gap between the free ends of the sliding rails 57 and 58 corresponds to the width of the workpieces 52a. Thereby the pressure surface of the pressure beam 23a, 1.65. the steel plate 65, presses always only there on the gl'lIldll'lg belt 34 where a workpiece 52a under the pressure beam 23a 1s located, regardless of the to-and-fro motions of the pressure beam 23a.
  • the cross belt grinding machine operates as follows:
  • the corresponding working width on the two pressure beams of the transverse grinding mechanisms 17 and 18 and on the sliding rail 58 of the pressure beam 23a as well as the extent of to-and-fro motions controlled by the limit switches 45 and 46 are adjusted.
  • the width of the workpieces 52a is not larger than the difference between the maximum width of the grinding belt 34 and the maximum to-and-fro motion limit, the full effective to-andfro motion limit will be effective in the described embodiment of the invention.
  • the workpieces 52a on the conveyor belt pass through underneath the pressure beams of the transverse grinding mechanisms 17 and 18 and the pressure beam 23a, which beams thereby are brought into and out of engagement with the workpieces 52a by the contact rollers arranged on their impact sides in a known manner.
  • the pressure beam 23a and thereto connected parts of the longitudinal grinding mechanism 23 are moved within the set limits continually to and fro crosswise to the direction of feed of the workpieces 52a.
  • the to-and-fro motions are transmitted from the reversible motor 42 through the spindle 43 to the reciprocating parts of the longitudinal grinding mechanism 23.
  • the limit switch 45 or the limit switch 46 is actuated by its cooperating end plate 28 or 29 whereby the reversible motor 42 and their direction of rotation of the spindle 43 are reversed.
  • the wide grinding belt 34 participates in these to-and-fro motions.
  • the lateral thrusts resulting during the grinding operation lessen lateral disorientation of the grinding belt 34 which entails that the described mechanisms for centering the grinding belt 34 need be less effective while effecting a better grinding.
  • the pressure beam 23a also participates in these toand-fro motions. Since on the one hand the workpiece 52a passes through the machine in a straight line and does not participate in the to-and-fro motions transverse to the feed direction, and on the other hand it must be contacted continuously as it passes through underneath the pressure beam 23a on its whole width by the grinding belt 34 pressed on by the pressure beam 23a, it is preferable that the actually effective pressing surface of the steel plate 65 displaces constantly on the same.
  • the rollers 74 roll alternately on the locked sliding rails 57 and 58 in dependence on the adjustments for the to-and-fro movement and the width of the workpiece 52a or they are in the space between the two free ends of the sliding rails 57 and 58 above the workpiece 52a where they execute no function. Then, just at the certain moment of the to-andfro motions when the rollers 74 do not roll on the sliding rail 57 or 58, the lifting rods 66 and 67 are in their lowest positions and the corresponding region of the pressing surface of the pressure beam 23a presses the grinding belt 34 during the grinding operation against the passing through workpiece 52a. Since the guide rail 55 is not axially movable in the pressure beam 23a, it moves up and down with the pressure beam 23a and is guided together with the sliding rails 57 and 58 guided thereon in the vertical direction in the vertical guiding devices 54 and 56.
  • the pressure beam 23a may have a rectangular or any other desired cross section, but it is advantageously box shaped and provided with a U-shaped rail b (FIG. 5) set in from above.
  • the ball bearings of the rollers 55a are fixed to said U-shaped rail 55b and the rollers run on the guide rail 55 extending inside the U-shaped rail 55b.
  • a rubber or an air cushion a or the like is inserted between the pressure beam 23a and the steel plate 65 in order to form an elastically resilient pressure beam 23a.
  • the to-and-fro movements can also be brought about by other means, for instance by a mechanical displacement of the axles of a return roller in the horizontal or vertical direction or by a guide roll.
  • the workpieces 52a moving along a straight line are transversely pre-ground by the two narrow grinding belts of the transverse grinding mechanisms 17 and 18 rotating in opposite directions and are thereafter ground in the direction of their travel by a wide grinding belt 34, whereby an outstanding quality of the upper surface of the workpieces 52a is attained by the to-and-fro motions of the longitudinal grinding mechanism 23 cooperating with the two transverse grinding mechanisms 17 and 18.
  • the to-and-fro movements of the longitudinal grinding mechanism can be interrupted following the rythm with which the machine is fed with workpieces.
  • the to-and-fro movements are always only effective in one direction on the single workpiece, because they are automatically switched, dependent on the speed they are fed in and on their length, by a contact roller arranged in front of the machine.
  • a contact roller may be provided instead of a pressure beam.
  • a machine for grinding plate-like large area workpieces comprising:
  • At least one of said grinding assemblies provides longitudinal grinding of said workpiece
  • (e) means to effect periodic back and forth movement of said longitudinal grinding assembly transversely to the direction of movement of said workpieces.
  • transverse grinding assembly is laterally disposed from said longitudinal grinding assembly to first receive said workpieces transported by said conveyor means.
  • a machine as claimed in claim 2 wherein said conveyor means includes an endless belt conveyor which carries said workpieces below said grinding assemblies.
  • transverse grinding assembly includes a vertically movable pressure beam located inside an endless grinding belt having a direction of movement transverse to the direction of movement of said workpieces.
  • transverse grinding assembly includes an endless laminated pressure belt disposed between said endless grinding belt and said pressure beam.
  • said longitudinal grinding assembly includes a pressure beam located on the inside of an endless grinding belt having a direction of movement parallel to the direction of movement of said workpieces.
  • said longitudinal grinding assembly includes means to press said pressure beam against the inside surface of said longitudinal grinding belt to effect grinding of said workpieces.
  • a machine as claimed in claim 7 wherein there are two transverse grinding assemblies laterally disposed from each other and from said longitudinal grinding assembly to first receive said workpieces transported by said conveyor means.
  • transverse grinding assembly includes a vertically movable pressure beam located inside an endless grinding belt having a direction of movement transverse to the direction of movement of said workpieces.
  • said longitudinal grinding assembly includes a device for adjusting the grinding belt to run in the middle portion of its drive and guide rollers.
  • the guide member is constructed to have a cross section like a circle, a rectangle and the like with guideways arranged on opposing sides or edges for guiding rollers carrying the lateral end plates.

Description

1970 K. HEESEMANN 3,53 MACHINE FOR GRINDING LARGE-AREA WORKIl EGlf-S Filed Nov. 13, 1967 4 Sheets-Sheet 1 Fig] Inventor ATTY Z Dec. 1, 1970 4 K. HEESEMANN 3,543,443
MACHINE FOR GRINDING LARGE-AREA WORKPIECES Filed Nov. 13, 1967 4 Sheets-Sheet 2 Fig.3
lnvenlor: KARL HEEJEMANA/ Dec. 1, 1970 K. HEESEMANN 3,543,443
MACHINE FOR GRINDING LARGE-AREA WORKPIECES Filed Nov. 13, 1967 4 Sheets-Sheet 5 Inventor.- KARL H5555 MAN/V ATTYS.
Dec. 1, 1970 K. HEESEMANN 3,543,443
- MAQHINE FOR GRINDING LARGE-AREA WORKPIECES Filed Nov. V13, 1967 4 Sheets-Sheet 4:
Fig.5
Fig.6 6?
Inventor:
K ARL HEA'SEMANN United States Patent 3,543,443 MACHINE FOR GRINDING LARGE-AREA WORKPIECES Karl Heesemann, 54 Friedenstrasse, Bad Oeynhausen-Rehme, Germany Filed Nov. 13, 1967, Ser. No. 682,270 Claims priority, application Austria, Nov. 11, 1966, A 10,443/ 66 Int. Cl. B24b 7/00, 9/00, 21/00 US. Cl. 51-3 24 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to a method of and a machine for automatically fine and subsequently very fine grinding of large-area workpieces.
The fine and very fine grinding of veneered, lacquered or otherwise laminated and also of solid workpieces having large surface areas is executed at present in a known and advantageous manner by cross grinding on two separate automatic belt-grinding machines.
In regard to surface make up, grinding out of the surface and depth of grind, cross grinding yields the best grinding quality. Here the pre-grinding is carried out as a transverse grinding, i.e. across the grain, and the finishgrinding as a longitudinal grinding, i.e. parallel to the grain.
Since in conventional machines the workpieces must be fed longitudinally for the transverse grinding and crosswise for the longitudinal grinding, it is necessary to change the direction of travel of the workpieces by 90 between the longitudinal and the transverse grinding. Thus, for the transverse and the longitudinal grinding separate machines must be used which are to be connected with each other by a so-called angle delivery apparatus so that the direction of travel of the workpieces undergoes the necessary change between the first and the second machines. Such installations call for high investments and require a large area for changing the direction of the workpieces passing through the machines. Moreover, due to the inertia of the workpieces, the speed of passage of the workpieces is limited during the direction change.
So far as the known wide belt grinding machines have been used as the second machine it has shown that these machines are not able to produce a very fine grinding of adequate quality since the feed direction of the workpieces and the running direction of the grinding belt extend parallel to each other. Since thus the grinding is not crosswise and therefore the grinding defects and traces add to each other instead of compensating for one another, the ground surfaces remain rough.
Furthermore, the grinding belt is always only worn out in the area which corresponds to the workpieces being ground. The hard glue joints, for example, which normally reoccur on the same lines on the workpieces always wear the grinding belt along the same longitudinal strips. The grinding belt subsequently clogs on these longitudinal 3,543,443 Patented Dec. 1, 1970 SUMMARY OF THE INVENTION It is the object of the present invention to avoid the disadvantages mentioned above and to provide an eflicient method of cross grinding large-area workpieces, and a machine for carrying out that method; which method comprises the steps of first grinding the workpieces transverse to their direction of feed, and subsequently grinding the workpieces substantially parallel to said direction of feed.
An important feature of the invention consists in that transverse grinding motions may be carried out when grinding the workpeces substantially parallel to their direction of feed.
The machine for carrying out the method comprises two supports, rails connecting said supports, a drive roller and an idler roller supported by said supports, a conveyor belt led around said rollers for feeding workpieces to be ground and moving preferably in one and the same direction, at least one transverse grinding mechanism mounted on one of said rails, a longitudinal grinding mechanism arranged downstream of the transverse grinding mechanism, and means for moving said longitudinal grinding mechanism to and fro relative to the workpieces passing through.
In an advantageous form of construction more than one transverse grinding mechanisms are arranged one behind the other and are each provided with a resilient pressure beam and an endless laminated pressure belt inserted between the grinding belt of the transverse grinding mechanism and said pressure beam.
The longitudinal grinding mechanism is preferably pro vided with a to-and-fro movable, advantageously endless grinding belt pressed against the workpieces to be ground by a pressure beam pressing against its inner side, while the grinding belt is equipped with a device to adjust it to run in the center of its drive and guide roller.
In a particularly advantageous embodiment of the longitudinal grinding mechanism the grinding belt drive and the guiding members as well as, if necessary, the pressure beam with its holding mechanism are mounted on a guide member movable transverse to the direction of travel of the workpieces. For this purpose a device such as a spindle may be provided.
It is further proposed by the invention constantly to change the effective pressing area of the grinding belt corresponding to the width of the workpieces in order to avoid cutting through the edges of the workpieces.
Another embodiment of the invention is possible wherein not the whole longitudinal grinding belt mechanism, but only its grinding belt is moved to and fro transverse to the direction of travel of the workpieces by a special controlling means.
The machine proposed by the invention excels in that the traces of the grinding are in an advantageous manner compensated while the workpiece runs through the machine in one and the same direction.
BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:
FIG. 1 is a schematic side view of a cross grinding machine according to the invention;
FIG. 2 is a cross section on the line 11-11 of FIG. 1;
FIG. 3 is a cross section through the guide member of the machine with an enclosing traverse and the grinding belt;
FIG. 4 is a front view, partly in cross section, of the pressure beam of the cross grinding machine;
FIG. is a cross section on the line VV of FIG. 4
and FIG. 6 is a cross section on the line VIVI of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS.1 and 2 show a cross belt grinding machine 10 mounted on two supports 11 and 12 connected by two lower connecting rails 13 and 14. An endless conveyor belt 15 for feeding workpieces 52a is led around a drive roller 15b and an idler roller 15a. A motor (not shown) drives the drive roller 15b and thus the conveyor belt 15 through an infinitely variable gear unit in preferably one and the same direction.
As shown in FIG. 1, two transverse grinding mechanisms 7 and 18 are fixed at a distance from one another on an upper connecting rail 16 extending between the supports 11 and 12 and are provided with two vertically adjustable pressure beams. It is self-evident that instead of two, also one or more than two tranverse grinding mechanisms may be provided which in the latter case are arranged one behind the other. Pressure rollers 19, and 21, 22 which may each be composed of many small rollers are arranged on each side of the two pressure beams of the two transverse grinding mechanisms 17 and 18 respectively. A contact roller is arranged in the same plane as the pressure rollers 19 and 21 and is actuated by the passing workpiece 52a to control the vertical movements of the pressure beams. The pressure beams are provided with mechanisms (not shown) with which the working width can be adjusted according to the width of the workpieces 52a passing through the machine. When deemed necessary an endless laminated pressure belt (not shown) may be inserted between the grinding belt and the pressure beam of the transverse grinding mechanisms 17 and 18. A longitudinal grinding mechanism 23 with a pressure beam 23a is arranged downstream of the two transverse grinding mechanisms 17 and 18. This longitudinal grinding mechanism 23 is designed as a wide belt grinding machine and comprises a fixed box-shaped guide member 24 which is mounted at one of its ends through the intermediary of a carrier arm 25 on the support 11 and is braced at its other end against the support 12 by a pivotable support 26. The connection between the pivotable support 26 and the support 12 can be disengaged, for example, when the grinding belt must be replaced, by means of a locking device like a locking lever 26a.
Two end plates 28 and 29, between which a traverse 30 which partly surrounds the guide member 24 is fixed,
are guided by means of guide rollers 31 on the box-shaped I guide member 24 which for example is provided with four guideways 27 bevelled on the edges of its length, so as to be rollable in a direction transverse to that of the workpieces 52a. Lateral sleeves 30a surround the parts of the guide member 24 which are not surrounded by the traverse 30. A drive roller 32 for a wide endless grinding belt 34 is driven by a motor 32a and rotatably mounted on an arbor 37 extending between the upper ends of the end plates 28 and 29. This wide endless grinding belt 34 is led around this drive roller 32 and lower guide rollers 35 and 36 located downstream and upstream of the pressure beam 23a. The grinding belt 34 is tensioned by means of a compressed air cylinder 38 with a piston rod 38a through parallel rods 39. This air cylinder 38 is mounted on the traverse 30. In order to maintain the grinding belt 34 in the middle portion of the drive roller 32, an electropneumatic control device which comprises for example a compressed air cylinder 40 is provided, through the intermediary of which the arbor 37 of the drive roller 32 is moved about a universal joint 41 or the like when one of the edges of grinding belt 34 touches one of lateral limit switches (not shown) located in the immediate vicinity of the edges of the grinding belt 34.
The traverse 30 with the end plates 28 and 29 and the further parts of the longitudinal grinding machine 23 connected thereto are movable on the guide member 24 by a reversible motor 42 connected to a spindle 43 passing through a spindle nut 44 built into the end plate 29. The to-and-fro motions produced by the reversible motor 42 of the above-mentioned parts of the longitudinal grinding mechanism 23 are limited by limit switches 45 and 46 which effect the reversal of the motor 42 whenever these moving parts reach an end position. The extent of the to-and-fro motions is adjustable by displacing the limit switch 45 on a rail 47.
The pressure beam 23a is vertically adjustable in the end plates 28 and 29 by means of a parallel linkage system 48. Pressure rollers 49 and 50, which may consist of a plurality of small rollers, are provided downstream and upstream of the guide rollers 35 and 36 for the grinding belt 34 to guide the workpieces 52a on the conveyor belt 15. A contact roller (not shown) is arranged in the same plane as the pressure roller or rollers 50 and is activated by the passing workpieces 52a automatically to control the upwards and downwards motions of the pressure beam 23a acted upon by a compressed air cylinder 51, its piston rod 51a and a shaft 5111 (FIG. 5). To achieve this end, clamping collars 51g are fixed on the shaft 51b mounted in mountings 510 which collars 51g carry the pressure beam 23a at its ends through the intermediary of levers 51d and 51e with a carrier foot 51 As the shaft 51b turns, the pressure beam 23a lowers or raises.
In order completely to grind the surfaces of the Workpieces 52a running straight through the machine while not cutting through its edges, the pressure surface of the pressure beam 23a moving to and fro with the movable parts of the longitudinal grinding mechanism 23 is controlled by an adjustment mechanism. This adjustment mechanism comprises a device for pre-adjustment according to the width of the passing-through workpieces 52a as well as an automatically working mechanism which are both dependent on contact roller control and reverse motions for adapting the pressure surface of the pressure beam 23a to the workpieces 52a guided by a guide bar 52.
The guide member 24 is closed at its free end by an end plate 53 (FIG. 2) on the upper end of WhlCh the reversible motor 42 and the spindle 43 are located. The lower end of this end plate 53 is provided with a vertical guiding device 54 (FIG. 4) in which one end of a guide rail 55 is guided so as to be unshiftable in its axial direction, whereas its other end rests in another vertical guiding device 56 arranged on the carrier arm 25. The vertical guiding devices 54 and 56 permit the guide rail 55 extending through the pressure beam 23a to move up and down with the same.
Because of its indirect connection with the end plates 28 and 29, the pressure beam 23a can move to-and-fro transverse to the direction the workpieces 52a are fed through the machine. The guide rail 55 in the pressure beam 23a is guided in a suitable way, for example by ball bearings and rollers 55a (FIG. 5 which are adapted to the particular profiling of the guide rail 55. As shown in FIG. 4, sliding rails 57 and 58 are guided to be movable and lockable in the guide rail 55, which sliding rails 57 and 58 are provided with oblique surfaces 57a and 5812 at the ends pointing towards one another. These oblique surfaces 57a and 58a extend adjacent both longitudinal edges of the workpieces 52a passing through the machine and their slope corresponds to the necessary slight slope of the lower pressure surface of the pressure beam 23a constructed as a steel plate 65. For pre-adjustment and locking, the sliding rail 58 is provided with holes 59 in which a lock pin 60 engages according to the width of the workpieces 52a passing through the machine, which lock pin 60 is passed on boht sides of the sliding rail 58 through a fork-shaped member 61 on the guide rail 55.
As shown in FIG. 6, the steel plate 65 is carried by the lower ends of lifting rods 66 and 67 fixed intermediate the two longitudinal edges of the steel plate 65. The upper ends of the lifting rods 66 and 67 are screwed into pivoting levers 68 and 69 fixed as well as a pivoting lever 70 on a common shaft 73 rotatably mounted in bearing blocks 71 and 72. On its free end the pivoting lever 70 carries a roller 74 which rolls on the sliding rails 57 and 58, respectively, during the to-and-fro motions of the pressure beam 23a.
The sliding rail 58 can be so adjusted that the gap between the free ends of the sliding rails 57 and 58 corresponds to the width of the workpieces 52a. Thereby the pressure surface of the pressure beam 23a, 1.65. the steel plate 65, presses always only there on the gl'lIldll'lg belt 34 where a workpiece 52a under the pressure beam 23a 1s located, regardless of the to-and-fro motions of the pressure beam 23a.
The cross belt grinding machine operates as follows:
For grinding uniform workpieces 52a of a given width, the corresponding working width on the two pressure beams of the transverse grinding mechanisms 17 and 18 and on the sliding rail 58 of the pressure beam 23a as well as the extent of to-and-fro motions controlled by the limit switches 45 and 46 are adjusted. When the width of the workpieces 52a is not larger than the difference between the maximum width of the grinding belt 34 and the maximum to-and-fro motion limit, the full effective to-andfro motion limit will be effective in the described embodiment of the invention.
The workpieces 52a on the conveyor belt pass through underneath the pressure beams of the transverse grinding mechanisms 17 and 18 and the pressure beam 23a, which beams thereby are brought into and out of engagement with the workpieces 52a by the contact rollers arranged on their impact sides in a known manner.
In order to attain the best possible quality of grinding by cross grinding the traces of grinding, the pressure beam 23a and thereto connected parts of the longitudinal grinding mechanism 23 are moved within the set limits continually to and fro crosswise to the direction of feed of the workpieces 52a. The to-and-fro motions are transmitted from the reversible motor 42 through the spindle 43 to the reciprocating parts of the longitudinal grinding mechanism 23. At the end of each motion the limit switch 45 or the limit switch 46 is actuated by its cooperating end plate 28 or 29 whereby the reversible motor 42 and their direction of rotation of the spindle 43 are reversed. The wide grinding belt 34 participates in these to-and-fro motions. The lateral thrusts resulting during the grinding operation lessen lateral disorientation of the grinding belt 34 which entails that the described mechanisms for centering the grinding belt 34 need be less effective while effecting a better grinding.
The pressure beam 23a also participates in these toand-fro motions. Since on the one hand the workpiece 52a passes through the machine in a straight line and does not participate in the to-and-fro motions transverse to the feed direction, and on the other hand it must be contacted continuously as it passes through underneath the pressure beam 23a on its whole width by the grinding belt 34 pressed on by the pressure beam 23a, it is preferable that the actually effective pressing surface of the steel plate 65 displaces constantly on the same. To this end, the rollers 74 roll alternately on the locked sliding rails 57 and 58 in dependence on the adjustments for the to-and-fro movement and the width of the workpiece 52a or they are in the space between the two free ends of the sliding rails 57 and 58 above the workpiece 52a where they execute no function. Then, just at the certain moment of the to-andfro motions when the rollers 74 do not roll on the sliding rail 57 or 58, the lifting rods 66 and 67 are in their lowest positions and the corresponding region of the pressing surface of the pressure beam 23a presses the grinding belt 34 during the grinding operation against the passing through workpiece 52a. Since the guide rail 55 is not axially movable in the pressure beam 23a, it moves up and down with the pressure beam 23a and is guided together with the sliding rails 57 and 58 guided thereon in the vertical direction in the vertical guiding devices 54 and 56.
The pressure beam 23a may have a rectangular or any other desired cross section, but it is advantageously box shaped and provided with a U-shaped rail b (FIG. 5) set in from above. The ball bearings of the rollers 55a are fixed to said U-shaped rail 55b and the rollers run on the guide rail 55 extending inside the U-shaped rail 55b.
As shown in FIGS. 5 and 6, a rubber or an air cushion a or the like is inserted between the pressure beam 23a and the steel plate 65 in order to form an elastically resilient pressure beam 23a.
The to-and-fro movements can also be brought about by other means, for instance by a mechanical displacement of the axles of a return roller in the horizontal or vertical direction or by a guide roll.
According to the described embodiment of the invention, the workpieces 52a moving along a straight line are transversely pre-ground by the two narrow grinding belts of the transverse grinding mechanisms 17 and 18 rotating in opposite directions and are thereafter ground in the direction of their travel by a wide grinding belt 34, whereby an outstanding quality of the upper surface of the workpieces 52a is attained by the to-and-fro motions of the longitudinal grinding mechanism 23 cooperating with the two transverse grinding mechanisms 17 and 18.
It lies within the scope of the invention alternatively to use another form of construction in which the workpieces 52a are passed through underneath a stationary longitudinal grinding mechanism while their longitudinal axes are held at a certain angle, i.e. oblique, to the original direction of travel, and after the termination of the grinding operation the workpieces 52a are fed back through the longitudinal grinding mechanism in the opposite (mirror image) direction onto the original feed-in way, whereby the effective pressing-on surfaces, such as for example the previously described steel plate 65, are so shifted that they are always above the passing-through workpiece.
According to a further embodiment of the invention, the to-and-fro movements of the longitudinal grinding mechanism can be interrupted following the rythm with which the machine is fed with workpieces. Thereby the to-and-fro movements are always only effective in one direction on the single workpiece, because they are automatically switched, dependent on the speed they are fed in and on their length, by a contact roller arranged in front of the machine.
Instead of a pressure beam also a contact roller may be provided.
While the method of and machine for grinding largearea workpieces has been shown and described in detail, it is obvious that this invention is not to be considered as being limited to the exact form disclosed, and that changes in detail and construction may be made therein within the scope of the invention, without departing from the spirit thereof.
What is claimed is:
1. A machine for grinding plate-like large area workpieces comprising:
(a) means mounting a plurality of grinding assemblies on a frame structure,
(b) conveyor means to transport said workpieces sequentially below said grinding assemblies,
(0) at least one of said grinding assemblies provides transverse grinding of said workpiece,
(d) at least one of said grinding assemblies provides longitudinal grinding of said workpiece, and
(e) means to effect periodic back and forth movement of said longitudinal grinding assembly transversely to the direction of movement of said workpieces.
2. A machine as claimed in claim 1 wherein said transverse grinding assembly is laterally disposed from said longitudinal grinding assembly to first receive said workpieces transported by said conveyor means.
3. A machine as claimed in claim 2 wherein said conveyor means includes an endless belt conveyor which carries said workpieces below said grinding assemblies.
4. A machine as claimed in claim 3 wherein said transverse grinding assembly includes a vertically movable pressure beam located inside an endless grinding belt having a direction of movement transverse to the direction of movement of said workpieces.
5. A machine as claimed in claim 4 wherein said transverse grinding assembly includes an endless laminated pressure belt disposed between said endless grinding belt and said pressure beam.
6. A machine as claimed in claim 3 wherein said longitudinal grinding assembly includes a pressure beam located on the inside of an endless grinding belt having a direction of movement parallel to the direction of movement of said workpieces.
7. A machine as claimed in claim 6 wherein said longitudinal grinding assembly includes means to press said pressure beam against the inside surface of said longitudinal grinding belt to effect grinding of said workpieces.
8. A machine as claimed in claim 7 wherein there are two transverse grinding assemblies laterally disposed from each other and from said longitudinal grinding assembly to first receive said workpieces transported by said conveyor means.
9. A machine as claimed in claim 8 wherein said conveyor means includes an endless belt conveyor which carries said workpieces below said grinding assemblies.
10. A machine as claimed in claim 9 wherein said transverse grinding assembly includes a vertically movable pressure beam located inside an endless grinding belt having a direction of movement transverse to the direction of movement of said workpieces.
11. A machine as claimed in claim 7, wherein said longitudinal grinding assembly includes a device for adjusting the grinding belt to run in the middle portion of its drive and guide rollers.
12. A machine as claimed in claim 7, wherein the pressure beam with the drive for the grinding belt is arranged so as to be able to move to-and-fro in the machine.
13. A machine as claimed in claim 7, wherein the pressure beam and the grinding belt with its drive are mounted in lateral end plates displacable by a spindle.
14. A machine as claimed in claim 13, wherein the lateral end plates are mounted on a guide member arranged in the machine transverse to the direction of passage of the workpieces.
15. A machine as claimed in claim 14, wherein the guide member is pivotably mounted in the machine.
16. A machine as claimed in claim 14, wherein the guide member is constructed to have a cross section like a circle, a rectangle and the like with guideways arranged on opposing sides or edges for guiding rollers carrying the lateral end plates.
17. A machine as claimed in claim 7, wherein the pressure beam has a pressing surface which is variable by means of an adjustment mechanism.
18. A machine as claimed in claim 17, wherein a steel plate is provided to serve as the pressing surface of the resilient pressure beam, which steel plate is held in a lowered position where the grinding is taking place in the area of the effective pressing surface and in a raised position on the outer edges by lifting rods and pivotable levers.
19. A machine as claimed in claim 18, wherein the free ends of the pivotable levers are guided by means of rollers on two sliding rails extending parallel to the pressure beam and leaving a free space between them which corresponds to the desired elfective pressing surface.
20. A machine as claimed in claim 19, wherein the free space between the sliding rails is adjustable as to length by the adjustable mounting of the sliding rails.
21. A machine as claimed in claim 19, wherein the sliding rails are mounted movably on a guide rail extending through the width of the machine.
22. A machine as claimed in claim 21, wherein the pressure beam is guided on the guide rail by means of rollers.
23. A machine as claimed in claim 21, wherein the pressure beam is box shaped and guided on the guide rail in its inside by rollers.
24. A machine as claimed in claim 7, wherein the pressure beam is connected by levers with a shaft which can be turned by means of a pressure-controlled adjustment apparatus.
References Cited UNITED STATES PATENTS 3,364,626 1/1968 Keyes 51-138 2,363,039 11/1944 Baldenhofer 5l3 1,191,045 7/1916 Verner 51.3 634,325 10/1899 Chain 51--302 JAMES L. JONES, JR., Primary Examiner US. Cl. X.R. 51--137
US682270A 1966-11-11 1967-11-13 Machine for grinding large-area workpieces Expired - Lifetime US3543443A (en)

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AT1044366A AT284656B (en) 1966-11-11 1966-11-11 Machine for cutting large workpieces

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JP (1) JPS4837318B1 (en)
AT (1) AT284656B (en)
BE (1) BE706147A (en)
CH (1) CH479367A (en)
CS (1) CS150203B2 (en)
DE (1) DE1652061C3 (en)
GB (1) GB1183597A (en)
SE (1) SE324649B (en)

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JPS4937292A (en) * 1972-06-26 1974-04-06 Timesavers Inc
US4449292A (en) * 1982-03-26 1984-05-22 Kaufman Lance R Method of clamping a circuit package to enhance heat transfer
US4502660A (en) * 1983-11-21 1985-03-05 Luther Leroy D Mold including side walls with locking projections
US4742650A (en) * 1986-11-07 1988-05-10 Conestoga Wood Specialities, Inc. Sanding machine
US20170073983A1 (en) * 2014-03-06 2017-03-16 Nela Gmbh Device for smoothing
CN108972269A (en) * 2018-07-27 2018-12-11 郑州法图曼工具磨具有限公司 A kind of grinding device with detection function
CN112720126A (en) * 2021-01-08 2021-04-30 南丰县致诚科技有限公司 Surface fine grinding device based on PS plate production
CN113560983A (en) * 2021-09-26 2021-10-29 徐州威通机械制造有限公司 Polishing device for flower disc casting
CN116638402A (en) * 2023-06-21 2023-08-25 杭州名尚钣金制造有限公司 Chamfering machine capable of collecting scraps for sheet metal part machining

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DE3426595A1 (en) * 1984-07-19 1986-01-30 Paul Ing.(grad.) 6925 Eschelbronn Ernst Device for grinding frame-like workpieces
JPS62120377U (en) * 1986-01-21 1987-07-30
DE202009019024U1 (en) 2009-11-27 2015-09-21 Lissmac Maschinenbau Gmbh Processing station and device for processing a workpiece
CN106826513A (en) * 2017-04-11 2017-06-13 王立乾 Aluminum veneer automatic polishing machine
CN108673651A (en) * 2018-03-30 2018-10-19 湖州南浔勇嘉木业有限公司 A kind of furniture wooden boards burr remover
CN109693485B (en) * 2019-01-30 2023-12-19 深圳灵创智能有限公司 Four-side centering center positioning fixture of four-station of integral type
CN114290204A (en) * 2021-12-27 2022-04-08 泰州星瑞精密工业有限公司 Automatic grinding and polishing processing equipment

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US2363039A (en) * 1941-12-22 1944-11-21 Thompson Grinder Co Surface grinder with auxiliary spindle
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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4937292A (en) * 1972-06-26 1974-04-06 Timesavers Inc
JPS568744B2 (en) * 1972-06-26 1981-02-25 Timesavers Inc
US4449292A (en) * 1982-03-26 1984-05-22 Kaufman Lance R Method of clamping a circuit package to enhance heat transfer
US4502660A (en) * 1983-11-21 1985-03-05 Luther Leroy D Mold including side walls with locking projections
US4742650A (en) * 1986-11-07 1988-05-10 Conestoga Wood Specialities, Inc. Sanding machine
US20170073983A1 (en) * 2014-03-06 2017-03-16 Nela Gmbh Device for smoothing
CN108972269A (en) * 2018-07-27 2018-12-11 郑州法图曼工具磨具有限公司 A kind of grinding device with detection function
CN112720126A (en) * 2021-01-08 2021-04-30 南丰县致诚科技有限公司 Surface fine grinding device based on PS plate production
CN113560983A (en) * 2021-09-26 2021-10-29 徐州威通机械制造有限公司 Polishing device for flower disc casting
CN113560983B (en) * 2021-09-26 2022-04-01 徐州威通机械制造有限公司 Polishing device for flower disc casting
CN116638402A (en) * 2023-06-21 2023-08-25 杭州名尚钣金制造有限公司 Chamfering machine capable of collecting scraps for sheet metal part machining

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CS150203B2 (en) 1973-09-04
DE1652061A1 (en) 1971-03-11
GB1183597A (en) 1970-03-11
AT284656B (en) 1970-09-25
JPS4837318B1 (en) 1973-11-10
DE1652061C3 (en) 1981-04-23
SE324649B (en) 1970-06-08
BE706147A (en) 1968-03-18
DE1652061B2 (en) 1980-06-19
CH479367A (en) 1969-10-15

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