DE1116570B - Additional device for measurement-controlled grinding machines as well as grinding machines that compensate for disc shrinkage with rapid, coarse and fine feed - Google Patents

Description

Additional device for measurement-controlled and automatic disc shrinkage compensating grinding machines with rapid, coarse and fine infeed, which is usually the case playing grinding process with an ordinary grinding machine or with a Centerless grinding machine consists in adjusting the grinding wheel head with a quick adjustment movement bring them to the workpiece. The rapid advance movement of the grinding wheel is used for rough grinding of the workpiece to an approximate final diameter Measure. After that, the feed is changed to a slow feed for the purpose of fine grinding switched and the workpiece ground to the final size. Then it takes place the distance between the grinding wheel head and the workpiece. The time of termination of the rough grinding and the start of the fine grinding is usually done by one signal indicating measuring device determined. The workpiece has its final Diameter reached, then this measuring device gives a second signal through which the slow feed is interrupted; the removal of the grinding wheel head from the workpiece then begins. The next workpiece to be ground can now be used will. This grinding cycle is repeated for all successive workpieces and results in intermittent dressing of the grinding wheel.

If the grinding continues, the diameter of the grinding wheel is used as a result of continued grinding and dressing processes. Is not a compensation device provided to compensate for this wear, the fast feed rate is of the feed cycle is getting bigger, due to the enlargement of the empty grinding with the ever-increasing retreat of the grinding wheel surface. This is undesirable because it increases the duration of the grinding cycle and increases production the machine is reduced.

There are already devices for the automatic compensation of grinding wheel shrinkage known by means of mechanical, electrical or hydraulic means that despite the wear of the grinding wheel the distance by which the wheel is fed during the feed movement is advanced, keep the same size. Here, the bench grinder is used by everyone The operation of the feed spindle is enlarged by the radial disc shrinkage Delivery route granted. However, the bench grinder is withdrawn to its original position with the participation of a hiking attack. In order to always have a constant, the respective Provision, reduced in order to achieve the stroke corresponding to the radial disc shrinkage, the stop is arranged on the feed spindle and with this via a at Withdrawing the bench grinder, the self-engaging freewheel gear is coupled.

The invention is to achieve that now also with known Precision grinding machines with a feed device on the rotatable and having axially displaceable feed spindle arranged balance beam on on the one hand from the express delivery drive and on the other hand from the combined Coarse and fine infeed drive is applied, the grinding wheel shrinkage continuously is compensable.

This is achieved according to the invention by adding the feed spindle at the end on the one hand, one that participates in the rashes of the coarse and fine adjustment drives and is free on the spindle movable drive part with stop nose and on the other hand next to this Drive part has an overrunning clutch with two according to the selected coarse and fine feed stroke mutually adjustable as well as enclosing the stop lug between them Attacks is arranged. When approaching the nose during the delivery process on first stop of the coupling housing this is now through the nose around the through the disc Reusable due to shrinkage, taken empty. During the withdrawal process the nose moves away from the first stop and reaches after it has been covered Coarse and fine feed stroke the second stop; in the then following reusable the nose with the second stop, d. that is, it twists from then on by snapping the One-way clutch of the feed spindle and adjusts it by the size of the disc shrinkage to. This is normally done by moving the machine in question here The infeed caused by the infeed spindle is thus, according to the invention, during the compensation process leaving; Compensation takes place here by turning the spindle and shifting it same by a transport thread.

The invention is described below with reference to the drawings. Here Fig.l shows a front view of a grinding machine, Fig.2 the one in Fig.1 machine shown, with some parts broken away to the new structure In relation to a known type of grinding machine, Fig. 3 shows a horizontal one Cross-section through the structure shown in FIG. 2, FIG. 4 shows an end view the line 4-4 of Fig. 3, Fig. 5 is a circuit diagram of a hydraulically operated delivery device, 6 shows a circuit diagram of an electrical delivery device, FIG. 7 in schematic form Representation of a measuring system.

The grinding machine bed 10 according to FIG. 1 carries a grinding wheel 11. The workpiece 12 is carried by a ruler 13 and pressed against the grinding wheel 11 by a regulating wheel 14 which rotates at a reduced speed. The regulating wheel 14 is carried by a grinding wheel head 15 which is fastened to a carriage 17 running on guide tracks 16. The carriage 17 slides on the grinding machine bed 10 and carries the ruler 13 at its front end (FIG. 1). The grinding wheel head 15 is fastened to the slide 17 with clamps 18 and 19. The grinding wheel head and carriage move as a unit on the grinding machine bed 10.

For adjustment purposes, the grinding wheel head 15 has a hand wheel 20 which can turn a spindle nut mounted in the wheel head 15 and in engagement with a feed spindle. When setting up the machine, the grinding wheel head 15 is connected to the slide 17 by tightening the clamp 18; the clamp 19 is released so that the slide 17 can move with respect to the grinding machine bed 10. The hand wheel 20 is then rotated in order to move the grinding wheel head 15 and the carriage 17 as a single component along the machine bed 10 until the guide bar 13 assumes its correct position. Now the clamp 19 is tightened and at the same time the clamp 18 is released, so that the desired setting of the regulating wheel 14 can take place independently of the guide bar 13. When the clamp 21 is tightened, the spindle nut is also tightened with respect to the wheel head 5 at the same time, so that the grinding wheel head 15 can be displaced by rotating the feed spindle. In the case of the horizontal beam-like delivery device (FIGS. 2 and 3), the rocker arm 29 is connected to a bushing 34 by means of pivot pins 30 and 31. This is rotatably mounted on the spindle by means of a thrust bearing 35 and a combined radial bearing and thrust bearing 36. These bearings 35, 36 are connected between spindle 23 and bushing 34 and are held in their place by a threaded nut 37 screwed onto the spindle and a shoulder 38 arranged on the spindle. The bar 29 moves the spindle as a whole in the axial direction and thus causes a quick adjustment of the grinding wheel head 15 and an adjustment of the grinding wheel 14 with respect to the workpiece.

Since, in the embodiment shown, the spindle 23 is rotatably mounted with respect to the bar 29, a clamping screw 39 (FIG. 2), which prevents relative rotation of the parts, is used for adjustment purposes. This is screwed into a threaded hole located in the pivot 30. The inner end of the clamping screw rests against the spindle 23 and prevents its rotation when it is firmly clamped against the spindle if the hand wheel 20 is rotated to turn the spindle nut when setting up the machine. In the following it should now be assumed that the machine has been set up correctly and that the clamping screw 39 has been loosened so that the spindle 23 can rotate. Furthermore, the assumption is that the clamp 21 (FIG. 1) is tightened, which results in a feed movement of the grinding wheel head 15 when the spindle is rotated.

At the end of the machine bed 10 on the right is a frame 45 attached, the beam 29 and other parts of the feed device for the grinding wheel 14 wears. This frame 45 has an end wall or housing 46 that contains the compensation device includes according to the invention. The spindle 23 (Fig. 2) has on its right-hand side End of an approach 47 on which the automatically working wear compensation device 48 is mounted, the details of which are shown in FIGS.

The beam 29 has a fork at each end in which blocks 49 and 50 are slidably received; pins 51 and 52 engage in them. The pin 52 is carried by a piston rod 53 which protrudes into a cylinder 54 arranged in the frame 45. On the piston rod 53 there is a piston 55 which is movable in the cylinder 54 and which assumes the position shown in FIG. 3 when hydraulic pressure fluid is fed to it via an opening 56. The liquid located in the right cylinder part can flow out of an opening 57. In this way, a rapid movement of the grinding wheel head 15 towards the workpiece is achieved and the spindle 23 is displaced to the left in the axial direction. If pressure fluid is fed to the cylinder 54 via the opening 57 while the opening 56 is connected to the reservoir, the piston 55 moves to the left end of the cylinder 54 and the beam 29 arranged on the pin 51 is pivoted and displaces the spindle 23 to the left using pivot pins 30 and 31 (Fig.2). An adjustable stop screw 58 is screwed into a threaded hole located in the right-hand end cap of the cylinder 54 in order to determine the retracted position of the grinding wheel head. Near the end of the rapid movement of the grinding wheel head 15, a console 59 actuates the lever 60 of a limit switch 2 LS in order to now initiate the rough grinding of the workpiece. In the illustrated embodiment, the bracket 59 is attached to the piston rod 53, but the bracket can just as well be attached to the beam 29 or can form part of the same. The limit switch 2LS is firmly connected to the frame 45 by means of a support bracket.

The movement of the grinding wheel head required for coarse and fine grinding 15 is carried out by a shaft 65, which is connected to a spindle 66 and a spindle on the frame 45 attached spindle nut 67 cooperates. The shaft 65 penetrates her opposite end a cap 68 and serves as a bearing for a sleeve that the Pivot pin 51 carries. Between the ends of the shaft 65 there is a key 69, which slides in the keyway of a gear 70, which is in the frame 45 of rolling bearings 71 is rotatably supported. As the gear 70 rotates, the shaft also rotates 65. The spindle 66 engaged with the spindle nut now moves the Shaft 65 to the left (Fig. 3). Here is the rotational speed of the gear 70 determining the infeed movement of the grinding plane head 15.

The hydraulic feed device of the grinding machine is shown in FIG. 5. The pressure fluid is generated by a hydraulic pump 75 which conveys the pressure fluid from a reservoir 76 into a line 77. The level of the pressure prevailing in the line is determined by a pressure relief valve 78. The rapid adjustment of the grinding wheel head 15 takes place by exciting a solenoid 1 SOL, whereby the coil 84 of the solenoid valve 85 is pushed to the right against the pressure of a spring 86. In this case, pressure fluid is fed from line 77 to a line 87 which is connected to the right side of a valve 88 and moves a coil 89 located therein to the left against the pressure of a spring 90. In this way, pressure fluid reaches a line 91 leading to the cylinder 54, which is connected to the opening 57 of the cylinder and allows pressure fluid to reach the end of the piston 55 on the right. At the same time, a line 92, which is in communication with the opening 56 of the cylinder, is connected via the valve 88 to the container line 79, so that the liquid located in the left-hand end of the cylinder 54 can run out of the cylinder. As a result, the piston 55 is moved quickly to the left and thereby also the feed spindle 23 (FIG. 3). After the rapid movement has ended, the switch 2 switches over LS and now energizes the solenoid 2SOL. The coil 95 located in the solenoid valve 96 moves to the right against the pressure of a spring 97 and gives the pressure fluid coming from the line 77 via a line 9 $ the path to the right-hand end of a control valve 99. The one arranged in this valve Coil 100 moves against the pressure of a spring 1.01 to the left and thereby connects the pressure line 77 with a line 102 and also with the left-hand end of a cylinder 103; in which a piston 104 provided with a rack is provided. The rack teeth of this piston mesh with the gear 70 (Fig. 3). The right-hand end of this cylinder is connected via a line 105 to the solenoid valve 106, the coil 107 of which is moved to the left against the action of a spring 108 when the solenoid 3 SOL is switched on. At this point in time, the line 105 is connected to a throttle valve 110 influencing the rapid adjustment and then to the valve 99 via a check valve 111 and a line 112. In the working position of the valve 99, the line 112 is connected to the supply line 79 so that the liquid can flow out of the right-hand end of the cylinder 103 and flow via the throttle valve 110 to the supply container 76. If the workpiece approaches its final dimension during the work process, a measuring system (to be described later) generates a signal which switches off the solenoid 3 SOL and consequently blocks the flow of the pressure fluid from the line 105 via the throttle valve 110. The liquid flowing through the line 105 consequently takes its way via a throttle valve 113 for fine adjustment to the line 112 and from there via valve 99 to the container line 79. The speed at which the piston 104 moves to the right is thereby reduced and in the same way the feed speed of the grinding wheel head 15 generated by the spindle 66 (FIG. 3) and the shaft 65.

When the workpiece is ground to its final dimension, the solenoids 1 SOL and 2SOL are switched off by a second signal generated by the measuring device. The solenoid valve 85 and the control valve 88 connected therewith return to the position shown in FIG. As a result, the piston 55 is moved into its right-hand position, as determined by the setting of the adjusting screw 58: At the same time, the solenoid valve 96 and the control valve 99 also assume the position shown in FIG Throttle valve 113 connected check valve 114 and via a line 105 into the right-hand end of the cylinder 103. The piston 104 equipped with a rack is quickly returned to its starting position, which corresponds to the retracted position of the grinding wheel head 15.

The measuring system generating the signals is shown in detail in FIG. A double-armed sensor 120 rotating on a shaft 121 is at one end of the arm provided with a polished surface 122 onto which a flowing out of a nozzle 123 Airflow hits. When the workpiece 12 is ground to the correct size, the air flow from the nozzle opening is restricted as a result of approaching the surface 122; This generates signals that influence the work of the accessory device. After finishing the grinding process, the feeler 120 is moved away from the workpiece, so that a new workpiece can be used for grinding. To do this To be able to, the sensor carries a toothed wheel which is in engagement with a toothed rack 125 124. Usually the rack is held by a tension spring 126 which is between a spring pin 1.27 attached to the rack and anchored to the shaft. If the rack is lowered at the end of the grinding process, the sensor will rotated away from the workpiece and also from the nozzle, so that a new workpiece is inserted will can. The sensor then returns to that shown in Fig. 7 Position back when the rack is released again.

The measuring device has a pressure control valve 131, which has a Line 130 is connected to a source of compressed air. The valve supplies compressed air constant strength to a variable throttle valve 132. The output of this Valve is via a line 133 and a flexible hose 134 with the opening 123 connected. The pressure prevailing in line 133 is increased via lines 137 and 138 supplied to the pneumatic relays 135 and 136. These relays are also available still with a reference pressure source via a line 140 and the output of a pressure control valve 139 in connection, the input of which is connected to the pressure line 130. Above Compressed air lines 141 and 142 are these pneumatic relays with electrical Pushbutton switches 143 and 144 connected to both the approach of the workpiece show the final size as well as the achievement of the finished size.

The manner in which the measuring system controls the work of the auxiliary device results from the circuit diagram shown in FIG. 6. The electrical circuit has two conductors 150 and 151 which are applied to the terminals 152 of a power network. The grinding process is initiated by actuating a pressure switch 153 which switches on a control relay 3 CR via a normally closed stop push button 154 and the normally closed contacts of a relay 1 OCR. This closes the normally open contact pair of relay 3 CR and thus creates a holding circuit for the pressure switch that keeps the relay switched on. At the same time, however, the second usually open contact pair of the relay 3 CR is closed and thus the solenoid 1 SOL is switched on, which actuates the valve 85 and causes a rapid movement of the grinding wheel head 15 towards the workpiece. Upon completion of the rapid movement, the limit switch 2LS is closed, thereby turning on the solenoid 2SOL which actuates the solenoid valve 96 and initiates the operation of the rack equipped piston 104 (Fig. 5). Finally, the solenoid 3 SOL is also connected to voltage via the normally closed contacts 155 of the electrical pressure switch 143 (FIG. 7). As a result, the solenoid valve 1106 operates and connects the rapid control throttle valve 110 to the line 105, so that the grinding wheel head 15 is displaced towards the workpiece at a coarse feed speed. At this time a signal lamp 159 (2LT) is switched on to indicate that the machine is performing a rough grinding operation in its working cycle.

As the final diameter is approached, the throttling or narrowing of the opening 123 (FIG. 7) increases the pressure prevailing in the line 133 up to a value at which the pneumatic relay 135 actuates the electrical pressure switch 143, whereby the contacts 155 are opened and a Group of usually open contacts 156 is closed. The solenoid 3 SOL is then switched off, whereby the valve 106 is closed and the return flow via the throttle valve 110 is interrupted. The liquid flowing out of the cylinder 103 is now forced to flow through the fine infeed throttle valve 113, as a result of which the feed movement of the grinding wheel head 15 is reduced. At the same time a signal lamp 160 (3LT) is switched on. Signal lamp 159 is switched off. When the workpiece has reached its final size, the pressure prevailing in line 133 is so great that the pneumatic relay 136 and the electrical push-button switch 144 are actuated. This opens the normally closed contacts 157 of the switch and closes the normally open contacts 158 of the switch. As can be seen from Fig. 6, the contacts 157 have no connection in the electrical circuit, while the closed contacts 158 switch on a control relay IOCR, whereby the contacts of this relay are opened. Relay 3 CR is switched off in this way, so that its contacts are opened and the solenoid 1 SOL is switched off. The solenoid valve 85 (FIG. 5) then returns to the position shown in FIG. 5, as a result of which the piston 55 moves to the right in the cylinder 54 and thereby removes the grinding wheel head 15 from the workpiece. When the second pair of contacts of the relay 3CR opens, the solenoid 2SOL is also de-energized; this has the consequence that the piston 104 equipped with the toothed rack returns to the position shown in FIG. The signal lamp 160 is switched off, while the signal lamp 161 lying in the line of the relay I OCR (whose contacts are closed) is switched on; this indicates that the workpiece has been ground to its predetermined diameter. After removal, a new workpiece can now be inserted into the machine for processing. At the same time, the sensor 120 is lifted from the workpiece by means of the rack 125 (FIG. 7) and the polished surface 122 moves away from the opening 123. As a result, the pressure in line 133 also falls and sets the pneumatic relays 135 and 136 out of order. The electrical switches 143 and 144 return to their normal positions, which has a closure of the contacts 155 and 157 and an opening of the contacts 156 and 158 result. The control relay 1OCR is de-energized again and causes the signal lamp 161 to go out. The contacts of the control relay 10CR return to their holding position, making the machine ready for the next grinding process. The first pair of contacts of relay 3 CR opens again and thereby holds this relay in an unexcited state until the push-button switch 153 is actuated again to begin the next grinding process.

From here on, the invention will now be described: To compensate for the disc shrinkage, a spur gear 165 is attached to the right-hand end of the shaft 65 (FIG. 3), which is in engagement with the gear 166; Gear 166 can rotate freely on the right-hand end of the spindle extension 47 by means of ball bearings 167. A driver with a stop lug 168, 169 (FIG. 3) is attached to this gear 166 with the omission of some teeth. The stop lug 169 works together with two stops 170 and 171 which are clamped by means of a nut 172 on a T-shaped bolt 173 on the circumference of a coupling housing 174. On a peripheral part of the clutch housing there is a toothing 175 (FIG. 4) which cooperate with corresponding toothing located on the underside of the stops 170 and 171 in order to prevent slippage between the two. The clutch housing is connected to a cam 179 by means of a wedge 178 (FIG. 3) and represents an overrunning clutch 180 between the spindle attachment 47 and the clutch housing held.

The grinding wheel head 15 is now in a position at the piston 104 equipped with a rack (Fig. 5) is at the left end of the Cylinder is located, then the stop lug 169 rests against the stop 170 (Fig. 4). When the grinding wheel head 15 moves axially, the shaft rotates 65 and drives the gear 166 via the gear 165, whereby a rightward movement the stop lug 169 takes place. This leaves the stop 170 and moves to stop 171. The initial setting of stop 171 on the clutch housing, readable on a scale 185 (Fig. 4), which shows the movement of the stop nose in tenths of a millimeter the adjustment of the grinding wheel head is selected so that the stop lug 169 does not touch the stop 171 of the rough grinding process. With continued sanding of the workpiece and taking into account the grinding wheel shrinkage Adjustment of the grinding wheel head until the stop lug 169 hits the stop 171 comes to the plant. If this is the case, the clutch housing 174 becomes a short one Moved distance to the right (see Fig. 4), and this results in a slip the cam coupling on the spindle attachment 47. If you pull the grinding wheel head on the At the end of the delivery process, the stop lug 169 also returns to its in Fig. 4 position shown back. Since the clutch housing, however, a small shift to the right has learned, the stop lug 169 rests against the stop 170 and stands up in this way the starting position again. Such a movement occurs in the drive direction of the cam coupling 179 and requires a certain left-hand rotation of the spindle attachment 47 and the spindle 23, so that the grinding wheel head 15 a is advanced a short distance to the workpiece. If the grinding wheel continues to wear this process is repeated. The extent of the axial, from the feed screw23 generated movement of the grinding wheel head is equal to the wear of the grinding wheel. The movement of the grinding wheel head generated by the shaft 65 thus increases 15 does not come on despite the grinding wheel wear. Also for the grinding process required time remains the same; it doesn't matter whether reducing the diameter the grinding wheel comes from normal wear or from a dressing process. If the grinding wheel is dressed between the grinding processes, then it will During the next grinding operation, clutch housing 174 is advanced by an amount that is equal to the thickness of the material used by the grinding wheel during the dressing process has been removed. At the end of the advance, i. H. in the time when the grinding wheel head is withdrawn, the stop lug 169 rests against the stop 170 and rotates the clutch housing and the feed screw by an equal amount, so that the The grinding wheel head is advanced a distance equal to the material thickness that has been removed from the grinding wheel during the dressing process.

Claims (1)

PATENT CLAIM: Additional device for measurement-controlled and disc shrinkage automatically compensating grinding machines with rapid, coarse and fine infeed, in the case of the bench grinder with each work step from the feed spindle to the radial disc shrinkage is granted increased infeed path, in which, however the retraction of the bench grinder to its starting position with the assistance of a hiking stop thus with a constant, the respective provision path minus the radial disc shrinkage corresponding stroke takes place that the stop is arranged on the feed spindle as well with this coincide automatically when the bench grinder is withdrawn Freewheel gear can be coupled, characterized in that in a known Feed device with on the rotatable and axially displaceable feed spindle (23) arranged balance beam (29) on one side (50, 52) of the express delivery drive (53, 55) and on the other (49, 51) by the combined coarse and fine adjustment drive (65 to 67, 70, 104) is acted upon, on the one hand a deflection at the end of the spindle of the coarse and fine feed drive (65 to 67, 70, 104) participant and freely the spindle (23) movable drive part (166) with a stop lug (168, 169) and on the other hand in addition to this one overrunning clutch (180) with two corresponding to the selected coarse and fine infeed stroke can be adjusted in relation to each other and the nose (168, 169) is arranged between enclosing stops (170, 171), on the one hand when the nose (168, 169) comes up against the first stop during the infeed process (171) of the coupling housing (174) this can be carried along empty through the nose and on the other hand when the nose (168, 169) touches the second stop (170) during the retraction process the infeed spindle (23) can be advanced by turning it by the size of the disc shrinkage is. References considered: U.S. Patent No. 2,718,101; German Patent Nos. 643179,545,675; "Werkstatt und Betrieb" magazine, 1956, P. 520.