US2690170A - Shaping device - Google Patents

Description

Sept. 28, 1954 Filed Feb. 10, 1953 R. ALLEN SHAPING DEVICE Sheets-Sheet l Regina ZcZ JNVE'NTOR A Z Ze/z MTTORNEYS R. ALLEN SHAPING DEVICE Sept. 28, 1954 3 Sheets-Sheet 2 Filed Feb. 10, 1953 FIG. 4.

11V VENTOE Reinalci AZZen/ Y I C ATTORNEYS Patented Sept. 28 1954 UNITED STATES TENT OFFICE Claims priority, application Great Britain December 30, 1952 3 Claims.

The present invention relates to shaping or dressing devices more particularly though not exclusively devices for dressing grinding wheels and has for an object to provide an improved method of and apparatus for dressing a grinding wheel.

Crankshafts and other machine components are usually formed with one or more cylindrical or conical portions blending with a radius at one orboth ends with other portions of larger diameter. After machining the said cylindrical or conical portion or portions to the desired contour, the desired finish is given by a grinding operation using a grinding wheel which is shaped to conform to the said contour.

It is general practice when shaping or dressing the grinding wheel by means of a suitable diamond dressing device, to dress the circumferential surface of the wheel and form the radius or radii in separate operations and it is therefore diflicult to ensure that the radius blends tangentially with the said surface. It is of great importance especially when grinding crankshafts,

that such tangential blending be achieved in the contour of the grinding wheel. According to the present invention there is provided a method of an apparatus for forming a contour having a straight portion blending with two radiused portions by means of a shaping or dressing tool which is moved along a continuous path corresponding to the said contour. Thus by applying the invention to the dressing of grinding wheels substantially tangential blending of the radii with the circumferential surface of the Wheel is ensured and the dressing operation is performed more accurately and with greater rapidity than heretofore.

The invention will now be described with reference to the accompanying drawings in which:

Figures 1 to 4 are diagrammatic representations illustrating the device according to the invention and the method of operation,

Figure 5 is a front elevation, partly in section taken along the line V-V of Figure 6, of a dressing device according to the invention and,

Figure 6 is a section taken along the line VIVI of Figure 5.

Referring firstly to Figure 1 of the drawings it will be seen that the device comprises a pair of substantially L-shaped side plates I and 3 supported upon an elongated member 2 for sliding movement longitudinally thereof. The longer legs of the L-shaped plates are adapted to be positioned one on either side of the grinding wheel to be dressed, indicated in broken line at It, the opposing faces of the shorter legs of the L-shaped plates being adapted to abut as at II. The plates are recessed to receive the member 2 and are arranged so that when the shorter legs are in abutment, the end faces 2A and 2B of the member 2 are in abutment respectively with the end faces IA and 3A of the recesses in the plates I and 3 the base of said recesses being indicated at 3 and 33 respectively and engaging the upper longitudinal surface of the member 2.

Each of the plates I and 3 as well as the member 2 is provided with an arcuate recess or channel which recesses, when the plates are in the abutting position shown in Figure 1 form an arcuate channel 6 extending continuously through the plates I and 3, and the member 2 and having as its centre of radius a point I positioned intermediate the longer legs of the side plates.

A tool carrier 4 adapted to support a dressing tool 5 is provided with an arcuate tongue 6C adapted to be slidably received in the channe1 6. The cutting point of the tool '5 is adjusted to a predetermined distance from the point I and it will be apparent that by moving the tongue 40 of the carrier I round the channel 6, the point of the tool will describe a circular are having a radius equal to the said predetermined distance. Stops 8 and 9 are provided on the plates I and 3 respectively and are adapted to be engaged by the carrier 3 to limit the angular displacement of the carrier to from a position in which the cutting point of the tool 5 engages a side face of the wheel Ill. 1

When it is desired to produce a contour of the grinding wheel Ill comprising a straight line having a radius at each end, the side plates I and 3 are set apart a distance equal to the length of the straight line as shown in Figures 2, 3 and 4. The sequence of the operation is shown in Figures 2, 3 and e and in Figure 2 it will be seen that the carrier 4 has been moved radially from the position shown in Figure 1 and the point of the tool has described part of the radius. Movement of the carrier is continued until the face 4B of the tongue engages the base 33 of the recess in the plate 3 in which position the point of the tool will have described the desired radius at one end of the line.

The member 2 is then moved in the longitudinal direction thereof laterally from left to right as shown in Figure 3 so that the point of the tool moves along a straight line parallel to the path of movement of member 2. Movement of member 2 is continued until the end face 2B thereof engages the end face 3A of the recess in plate 3 (Figure 4;). In this position the arcuate recesses in the member 2 and the plate 3 are in alignment and the tongue 4C is moved round the arcuate recess in plate 5 to complete the radius at the other end of the line.

The operation is then reversed by moving the carrier 3 from right to left as seen in the figures; firstly radially until the face 6A of the tongue engages face B of the plate I then laterally until the end face 2A of the member 2 engages the face IA of plate I, and then radially to complete the desired contour.

It will be seen that the point of the tool 5 describes the desired contour in a continuous movement in either direction without interruption at the points of tangency, and that the change from lateral to radial movement is a fully automatic result of pressure exerted on the tool carrier i in either direction longitudinally of the member 2.

It will be apparent that by omitting the use of plate I or of plate 3 a contour can be described having a single right or a single left hand radius blending tangentially with a straight line.

Referring now to Figures 5 and 6 there is shown one construction of a dressing device for carrying into effect the method of operation described above with reference to Figures 1 to l of the drawings.

The device shown in Figures 5 and 6 is adapted for mounting on a grinding machine and for this purpose is provided with a substantially U- shaped base l2 to which is secured by screws l3 and dowls i l a similarly shaped flanged cover it thereby providing an open topped U-shaped housing in which two substantially L-shaped side plates it and If, and a sliding member it are slidably positioned in a manner hereinafter described. The cover it is provided with an apertured lug H9 at each end thereof adapted to receive extension pieces for mounting the device between the headstock and tailstock of the machine.

fhe side plates and ii are flanged around a portion of the periphery and respectively have secured thereto a cover plate 20. The cover plate secured to the side plate in spaced relation therewith by means of screws 21 and dowels 2 2. The base of each side plate is recessed as at to receive the sliding member E8 of substantially L cross section and having formed therein an arcuate recess 2f adapted to receive an arcuate tongue 25 of a carrier member 25. The side plates 56 and H are each provided with an arouate recess 21 which, when the plates are in abutting relation as shown in Figure 5, form together with the recess 24 in the member it, a continuous arcuate recess or channel having as its centre of radius a point 28 positioned between opposing edges of the longer legs of the L-shaped side plates.

The shorter legs of the side plates, the sliding member Ill and the lower portion of the carrier 25 are slidably engaged one with the other and with the inner surface of the base 32 and/or the cover 15, the member it being constrained to slide longitudinally of the housing by means of a tenon strip 54 secured to the inner surface of the cover !5 by screws 29 and extending longitudinally thereof and engaging in a recess til extending longitudinally of the member M3.

in a similar manner the side plates 56 and ii are constrained. to slide longitudinally of the housing by a further tenon strip 3| secured to the inner surface of the base 12 by screws 32 and engaging in a recess 33 in each of the cover plates 20.

In order to effect movement of the side plates longitudinally of the housing, each plate is provided with a screw threaded bore 3 extending inwardly from the outer edge surface of the plate and adapted to receive the screw threaded end 35 of a spindle 36 rotatably supported in the end flange of the cover l5 and secured against sliding movement with respect thereto by a screw 3'! extending through the flange and engaging in an annular recess 38 in the spindle 36. The outer end of the spindle 36 is provided with a knurled turning knob 39 and it will be apparent that by rotating the spindle 36 by means of the knob 39, the side plate will be caused to slide longitudinally of the housing.

The side plates can thus be adjusted longitudinally of the housing to the desired spacer; apart position by means of the respective turning knobs Bil and are adapted to be locked in the adjusted position by means of screws it engaged in screw threaded apertures in the cover if: and adapted to engage the side plate so that upon tightening the screw it the side plate is gripped between the cover it and base [2 and thus locked in position.

To enable the distance apart of the side plates Hi and IT to be accurately determined each plate has secured thereto a peg ll extending through a longitudinally extending slot 52 in the cover 45. The pegs H are adapted to extend sufliciently beyond the outer surface of the cover to permit the measurement of the distance between them by means of a slip gauge, micrometer or similar measuring device. Alternatively a gauge plate having two apertures spaced apart a distance equal to the desired separation of the side plates could be adapted to be secured over the pegs ll, each peg being received in one of the apertures.

'The upper end of the carrier member 265 has rigidly secured thereto by means of a screw 3 a tool supporting pillar id provided with an aperture d5 adapted to receive the dressing tool (not shown) a screw threaded bore l6 extending at right angles to, and intersecting the aperture which bore is adapted to receive a locking screw (not shown) for locking the dressing tool in position longitudinally with respect to the aperture so that the point of the tool is at the required distance from the point 28 to give the desired radius.

A handle M is secured to the free end of the pillar l4 extending downwardly therefrom by means of which the movement of the carrier member 26 as hereinbefore explained with reference to Figures 1 to 4 of the drawings, can be'eifected.

The upper face it of the tool supporting pillar M is machined at precise dimension from the centre point 28 of the arcuate recess so that the point of the dressing tool can be set to give the desired radius by adjusting the point of the tool with respect to the surface 5.8 by means of a slip gauge or like measuring device.

The length of the arcuate tongue '25 of the carrier member 26 is made equal to the length of the arcuate recess it in the slidable member it and is symmetrical with respect to the axis of the carrier member so that when the tongue is fully positioned in the recess as shown in Figure 5, "'iecarrier member 2% extends at right angles to the longitudinal axis of the housing. Stops as and 5B are provided respectively in the arcuate channels in side plates l6 and I? and serve to ony limit angular movement of the carrier member so that when the tongue 25 engages the stop 49 or 50, the carrier member extends parallel to the said longitudinal axis.

Thus by positioning the device on a grinding machine with the longitudinal axis of the housing lying parallel to the axis of the grinding wheel and the plates I6 and I1 separated by a distance equal to the length of straight contour, and the dressing tool adjusted in the supporting pillar 44 so that the point of the tool is spaced from the centre point 28 of the arcuate recess a distance equal to the required radius contour, the shaping process as described with reference to Figures 1 to 4 can be performed by a constant pressure exerted on the handle 41 in one direction or the other.

Suitable dust excluding shields (not shown) may conveniently be provided on the device to prevent the entrance of the fine dust resulting from the shaping operation into the housing and into the space between the side plates l6 and I! and their respective cover plates 20.

It will be apparent that the device described with reference to Figures 5 and 6 is fully operative to carry into effect the method as described with reference to Figures 1 to 4 but it will be understood that the invention is not limited to the above described construction of shaping device.

What I claim is:

1. A shaping or dressing device for dressing a grinding wheel having a straight peripheral portion and two rounded edge portions, the said device comprising a tool holder movably mounted on the device and supporting a dressing tool, a pair of relatively fixed arcuate guides supported on the device in spaced apart relation transversely of the wheel, a slidable arcuate guide supported on the device for rectilinear sliding movement between said relatively fixed guides parallel to the said straight peripheral portion of the wheel, the said arcuate guides being of equal radius and the said slidable guide being movable from a first position in which one end thereof engages one of said relatively fixed guides in co-planar relation to form a continuous arcuate guide therewith to a second position in which the other end of said slidable guide engages the other ofsaid relatively fixed guides in co-planar relation to form a continuous arcuate guide therewith, and means on said tool-holder for sequentially engaging the said arcuate guides for movement therealong whereby said tool-holder is first angularly displaced to move the tool over one of the rounded edges of the wheel, is then displaced parallel to the straight peripheral portion of the wheel to move the tool alon the said straight portion, and is then again angularly displaced to move the tool over the other of said rounded portions of the wheel.

2. A shaping or dressing device as claimed in claim 1 provided with means for adjustably positioning the said relatively fixed arcuate guides transversely of the Wheel to permit the device to be used for dressing wheels having straight peripheral portions of different length.

3. A dressing device for dressing a grinding wheel having a straight peripheral portion and two rounded edge portions, the said device comprising a housing having a pair of spaced side plates positioned one on each side of the wheel, a member supported in said housing for rectilinear sliding movement between said side plates parallel to the said straight peripheral portion of the wheel, an arcuate channel extending over the said side plates and the said slidable member and having a centre of radius positioned intermediate the said side plates, a tool carrier member supporting a dressing tool for dressing the grinding wheel, an arcuate tongue on said tool carrier engaging in said arcuate channel for movement therealong, means for relatively adjusting the said side plates transversely of the wheel, and a handle secured to said tool carrier member for moving the arcuate tongue along the arcuate guide sequentially from one side plate to the other side plate whereby the said carrier member is first angularly displaced by movement of the tongue along the arcuate channel of said side plate to move the tool over one of the rounded edge portions of the wheel, is then rectilinearly displaced parallel to the straight peripheral portion of the wheel by sliding movement of the sliding member to move the tool along the said straight portion, and is then again angularly displaced by movement of the tongue along the channel in the other side plate to move the tool over the other rounded edge of the wheel.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 838,250 Hudlow Dec. 11, 1906 2,294,492 Wilson Sept. 1, 1942 2,304,970 Turner Dec. 15, 1942 2,326,661 Lalime Aug. 10, 1943 2,446,833 Johnson Aug. 10, 1948 2,617,403 Beauchemin Nov. 11, 1952

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