US3009446A - Stroking device - Google Patents

Description

1961 J. SUNNEN 3,009,446

STROKING DEVICE 4 Sheets-Sheet 1 Filed March 11, 1960 Nov. 21, 1961 J. SUNNEN 3,009,446

STROKING DEVICE Filed March 11, 1960 4 Sheets-Sheet 2 NOV. 21, 1961 J, SUNNEN 3,009,446

STROKING DEVICE Filed March 11, 1960 4 Sheets-Sheet 3 Nov. 21, 1961 J. SUNNEN STROKING DEVICE 4 Sheets-Sheet 4 Filed March 11, 1960 FIGB z WI I I mw x, a HHHH w\\\-\ a 3 III L m m L .6 F

FIGIZ FIGJ l United States Patent 3,009,446 STROKING DEVICE Joseph Sunnen, 400 S. Watson Road, Clayton, Mo. Filed Mar. 11, 1960, Ser. No. 14,239 11 Claims. (Cl. 12141) The present invention relates to motion producing devices in general, and more particularly to a device for producing a variable length stroke for a working member.

Various means have heretofore been devised for reciprocating or stroking working members, such as a rotating honing mandrel. The known devices for the most part move the working member back and forth over a uniform length repeating stroke, and in so doing produce vibration in the mechanism and error and unevenness in the worked surface and also in the working member. Furthermore, the known devices are not as efficient as they could be because they do not retain the working member in contact with the surface being worked for a maximum portion of the working time. Still further, the known devices are not readily and easily adjusted for operation on diiferent sizes of work and on different size work surfaces. For these and other reasons the known devices are not as eflicient, flexible, versatile, or easily adjusted as the present device. To a large extent these and other objectionable features of the known devices are overcome by the present invention which teaches the use and construction of a device capable of producing variable length strokes for an operation, such as a honing operation, which strokes are adjustable as to length, time duration, and also as to the distribution of time Within the individual strokes. The present device is also more efiicient than known devices because it retains the working member in contact with a member being worked for a greater portion of the working time. Still further, the present device eliminates sudden well defined movements and reversals in movement and vibration of the members and in this way also eliminates surface imperfections.

Briefly, the present invention consists of a device for controlling the movement of a working member, such as a rotating abrasive member, during operation thereof and comprises reciprocating means operatively connected to a working member, said reciprocating means including cam means which provide the basic pattern of movement, and other means operatively connected to the working member and controlled by the basic movement thereof for modifying said basic movement, said last named means having a connection to the cam means.

An important object of the invention is to improve the accuracy and efiiciency of working members such as a rotating abrasive member or hone.

Another object is to produce a variable length and adjustable stroke pattern.

Another object is to prolong the life of abrasive elements.

Another object is to increase the time during which an element, such as an abrasive element, is in contact with a surface being worked thereby.

Another object is to increase the efliciency of honing and abrading operations.

Another object is to eliminate imperfections in a honed surface caused by vibration and other sudden movements between relatively reciprocating members.

Another object is to eliminate sudden and well defined changes in the direction of movement of a member.

Another object is to provide means for adjusting the distribution of time in a stroking operation so that the time during which a working member is engaged with different portions of a working surface can be varied.

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Another object is to provide relatively simple and inexpensive means for varying the length and duration of stroke of a reciprocating member.

Another object is to provide means for adjusting the distribution of working time of a work member on a surface to accurately finish a surface on a member formed of several dififerent hardness materials and to do so in a single and continuous operation.

Still another object is to provide means for stroking a member which are relatively easy to construct and which can be applied to new as well as to existing equipment.

These and other objects and advantages of the present invention will become apparent after considering the following detailed specification in conjunction with the accompanying drawings, wherein:

FIG. 1 is a fragmentary elevational view, partly in section, showing a stroking device for a working member constructed according to the present invention;

FIG. 2 is a horizontal section taken on line 2-2 in FIG. 1;

FIG. 3 is a fragmentary elevational view similar to FIG. 1 showing the control means in a different position of adjustment;

FIG. 4 is an enlarged view of a typical cam for use with the device of FIGS. 1-3;

FIG. 5 is a graphical representation of the basic stroke movement as a function of time using the cam of FIG. 4 on the stroking device of FIGS. 1-3;

FIG. 6 is a graphical representation of the basic stone movement shown in FIG. 5 as modified by the present stroking device to eliminate pronounced reversals of movement and to srnoothen the operation;

FIG. 7 is a graphical representation shown in phantom outline of the pattern of movement of a rotating stone member in a hole, the stone having a length shorter than the hole depth;

FIG. 8 is a graphical representation similar to FIG. 7 wherein the stone length is longer than the hole depth;

FIG. 9 is an enlarged view showing a modified form of cam for use on the present device;

FIG. 10 is a graph of the stone movement produced by the modified cam of FIG. 9;

FIG. 11 is a fragmentary sectional view illustrating in exaggerated form the kind of stone wear and hole imperfection that results when a uniform length repeating stroke is employed and the stone length is greater than the hole depth, and

FIG. 12 is a fragmentary sectional View similar to FIG. 11 showing in exaggerated form the kind of stone wear and hole imperfection that results when a uniform length repeating stroke is employed and the stone length is shorter than the hole depth.

Referring to the drawings by reference numbers, the number 10 in FIG. 1 refers to a reciprocating honing machine constructed according to the teachings of the present invention. In the embodiment shown, the machine 10 has a stationary platform 12 on which is positioned one or more honing stations designated generally by the number 14. An hydraulic plunger assembly 16 extends upwardly through the platform 12 and is connected at its upper end to a movable honing head 20 carried in an overhead position on the machine 10. The honing head 20 is moved up and down by the plunger 16 and in so doing moves one or more depending rotating honing mandrels 22 up and down in holes formed in work pieces, such as in the work piece W. The mandrel 22 carries one or more suitable abrasive members such as the stone 26, and during a honing operation the mandrel 22 and the stone 26 move up and down in the hole in the work piece and hone the hole to a desired dimension and smoothness. More than one honing operation can be performed simultaneously by having a plurality of honing stations, each being equipped with its own rotating mandrel and abrasive, and if desired the same work piece can be shifted from station to station for successively finer and more accurate honing and finishing. If this is done, either the head 20 or the platform 12 is shifted. When a workpiece has been operated on at every station, it is removed from the machine and replaced with another workpiece. In this Way a plurality of honing operations can be performed simultaneously at the different work stations all under control of the same reciprocating head 26 the movement of which will be described more in detail hereinafter.

The characteristics of the reciprocating motion which is imparted to the honing head 20 (or to the platform 12) during a honing operation are important because they contribute to the accuracy of the honing, and also because they provide an improved wear pattern of the parts and increase the honing efiiciency. In the past, devices have been constructed using uniform length repeating strokes. These known devices have resulted in uneven stone and hole wear, inaccuracy and imperfection of the honed surfaces and inefficiency and costly repair and maintenance of parts. In the known devices the life of the stone and other parts is also substantially shorter than in the present device.

The present device overcomes these and other disadvantages of using a uniform length repeating stroke and in so doing produces improved and more uniform stone wear and extremely accurately honed surfaces. An important effect of these advantages is the fact that the life of the stones is substantially increased thereby resulting in less maintenance cost, less repairs and less replacement of parts and less down time. The present device also includes means for controlling the reversing of the direction of the honing movement between successive strokes so as to avoid surface imperfections in the honed surface which would otherwise result when one stroke ends abruptly and the next stroke begins in the opposite direction. By so providing, noise and vibration are also greatly reduced.

In FIGS. 11 and 12 are shown in exagerated form the common types of defects that are caused by using a uniform length repeating honing stroke. In FIG. 11 the honing stone 26a is shown longer than the hole depth. With this condition the center portion of the honing stone wears more than the ends because the center portion is in contact with the hole during a greater portion of the honing cycle than the end portions. Therefore, the center of the stone wears faster than the ends. In fact, the ends of the stone may be out of contact with the work surface altogether and never Wear. The error in the work surface for this condition is also shown in exaggerated condition, the work surface having its smallest diameter at the center becoming larger at the ends.

In FIG. 12 the opposite condition is shown wherein the stone 26b is shorter than the hole, again using a uniform length repeating stroke. In this situation the stone 26b is substantially fully in the hole at all times and the ends of the hole are out of contact with the stone more than the center of the hole. As a result the center of the hole wears more than the ends and the hole tends to become barrel shaped. The stone also wears unevenly under these conditions becoming convex shaped on its wear surface.

The present invention consists of mechanism for controlling the movement of the head 20 to produce uniform stone wear and to minimize surface defects in the honed surface such as those described above. More specifically the present invention consists of means for controlling the movement of the head by moving it along variable length strokw to produce a more even wear pattern for the honing stones and for the surface being honed and to thereby produce more accurately honed surfaces. Obviously, the same mechanism which controls the movement of the head in the present device could also be used alternatively to control the movement of the platform 12 and the work with the same desirable results.

In the particular embodiment chosen to illustrate the invention, the head 20 is connected to the plunger assembly 16, and the plunger assembly 16 extends downwardly therefrom into a master cylinder 28. The master cylinder 28 has a piston 36 which is connected at the lower end of the plunger assembly 16. One end of a feed conduit 32 is connected to the master cylinder 28 adjacent to the upper end thereof and the opposite end of the feed conduit 32 is connected to a port 34 on a control valve 40. Another feed conduit 36 has one of its ends connected to the lower end of the master cylinder 28 and its opposite end connected to another port 38 on the valve 46. The valve 40 has a bore 42 with plunger member 44 slidably positioned therein. The plunger member 44 has a pair of spaced annular bore contacting land portions 46 and 48 which are positioned in the bore 42 ad jacent to the outlet ports 38 and 34 respectively, and the positioning of the lands 46 and 48 in the bore 42 controls fluid flow through the control valve 40. The valve 40 also has an inlet port 50 which is connected by an inlet conduit 52. which has its other end connected to a source of fluid pressure (not shown).

The plunger member 44 is biased upwardly in the valve 40 by a spring 54 which is positioned in the lower extension 55 of the bore 42. The plunger member 44 also has an upwardly extending portion 56 which extends out of the upper end of the control valve 40 and through a suitable opening in a support frame 58. Fluid flow through the valve 40 between the inlet port 50 and the outlet ports 34 and 38 is controlled by pressure applied on the upwardly extending portion 56 of the plunger member 44. For example, when the plunger portion 56 is pressed and moved downwardly the annular plunger land portion 46 moves downwardly and closes the outlet port 38 cutting off communication to the lower end of the master cylinder 28. At the same time the plunger land 48 partially uncovers the outlet port 34 and thereby establishes flow communication to the upper end of the master cylinder 28 through the conduit 32. The more the port 34 is open by movement of the plunger 44 the greater will be the fluid flow into the master cylinder 28, and hence the faster will be the movement of the head 20 in a downward direction. If the pressure is relieved on the plunger member 56 so that the plunger member 44 is allowed to move upwardly the opposite condition will take place in which the outlet port 34 is closed by the land portion 48 and the outlet port 38 is open. When this occurs pressure fluid is fed to the lower end of the master cylinder 28 to move the plunger assembly 16 and the head 20 upwardly.

The land portions 46 and 48 are of such size and spacing that at one point they just, or almost just, cover both outlet ports 34 and 38. The slightest displacement of the plunger 44 in either direction disturbs this intermediate position and causes fluid flow to one of the ends of the master cylinder 28. Being able to move the plunger 44 to a position restricting or almost restricting flow to the master cylinder is important to the present device for reasons which will become apparent hereinafter.

Also of importance to the present invention are the means which are provided to control the movement and positioning of the plunger 44 and thereby to control the movement of the head 20.

The mechanism which controls the movement of the plunger 44 is shown in detail in FIGS. 1, 2 and 3 and comprises a fixed support column 60 attached to the frame support 58. A cross arm 62 is pivotally connected adjacent to the upper end of the column 60 by a pin 64 and extends a short distance to right from the column 60 and a longer distance to the left therefrom. The arm 62 is pivotally connected adjacent to its right end to a downwardly extending rod 66. The lower end of the rod 66 carries a cross pin 68 which extends into curved slots 70 formed in similar spaced and connected amplifier members 72, two of which are provided as shown in FIG. 2. The spaced amplifier members 72 are attached to each other by suitable means such as bolts 74, nuts 76 and spacers 78, and a spring 80 is connected between the right end of the cross arm 62 and the right end of the amplifiers 72. Another spring 82 is connected between a fixed bracket member 84 on the column 60 and a spacer member 86 mounted between the amplifiers 72. The spring 82 is positioned adjacent to the right side of the column 60 and exerts upward clockwise tension on the amplifiers 72 relative to the cross pin 68.

The spring 82 also biases a cam follower roller 88 carried on a shaft 90 between the amplifiers 72 into engagement with a cam 92. The cam 92 is rotatably mounted on a shaft 93 and is rotated by suitable drive means (not shown) during operation of the device to produce the basic pattern of movement of the head 20 as will be shown hereinafter. The particular cam 92 shown in FIGS. 1, 3 and 4 has a large cam lobe 94, a smaller cam lobe 96, and two intermediate low spots 98 and 100 which are between the lobes 94 and 96. It should be noted that the intermediate low spot 98 is a shorter distance from the axis of the cam 92 than the intermediate low spot 100.

If the complete control of the movement of the head 20 were in the cam92, thehead 20 would move up and down in a pattern defined by alternate different length strokes depending for their speed, length and direction entirely upon the shape of the cam. This by itself would constitute some improvement in a honing operation. FIG. 5 shows a graph of head movement where the control of the valve 40 and the master cylinder 28 depends substantially entirely on the operation of the cam. The graph in FIG. 5 was made during an actual operation of the machine, and clearly illustrates the pattern of movement of the head when the control valve 40 is under control of the cam only. During this type of operation the cross pin 68 on the lower end of the rod 66 is held in a fixed position and the valve plunger moved over a relatively wide range of movement depending on the position of the cross pin 68 in the slots 70. In so doing one or the other valve outlet ports 34 or 38 at a time is open a relatively substantial amount thereby causing rapid fluid flow into the master cylinder 28 and rapid move- I ment of the plunger assembly 16 and head 20. This also causes sudden well defined reversals of direction of the head movement. No attempt is made when the head is under the sole control of the cam means to meter or regulate. the flow through the outlet ports 34 and 38 of the control valve 40 to dampen and smoothen the operation and eliminate sudden sharp reversals in the movement. This is clear from the graph in FIG. 5 which shows that the head 20 reverses its movement very suddenly. The steep slope of the curve of FIG. 5 also illustrates that the, head 20 is moving rapidly and is moving over a relatively wide range in both directions. It is clear from FIG. 5, however, that the cam by itself produces different length strokes even though the operation is rapid and choppy and produces considerable vibration. Therefore, simply varying the length of the strokes by itself does not-solve the whole problem or create the most smooth and efiicient operation.

In order to eliminate these undesirable conditions means are provided in the present device to modify the basic movement of the head. This is done by moving the position of the cross pin 68 in a direction to oppose the cam action and meter the flow of fiuid through the valve 40. The mechanism that modifies the movement of the head is of a servo type mechanism and is controlled by the movement of the head 20 itself. The mechanism includes arod 102 fixedly connected at its upper end to l the head 20 and adjacent to its lower end to the leftward extension of the cross arm 62. A threadedly adjustable connection 104 is provided between the rod 102 and the arm 62 which consists of a threaded portion 106 on the rod 102, and threaded locking bolts 108 on opposite sides of a tubular sleeve 110 'on the end of the arm 62. A spring (not shown) could also be provided at the connection of the rod 102 and the arm 62 if desired. The distance along arm 62 from the rod 102 to the pivot pin 64 is greater than the distance along the rod 62 from the column pivot 64 to the connection with the downwardly extending rod 66.

The operation of the device is as follows: When the head 20 is moving upwardly under control of the cam 92 as described above, the rod 102 moves upwardly a like distance because of its fixed connection to the head 20. When the rod 102 is moving upwardly it moves the arm 62 clockwise about the pivot pin 64-, and in so doing moves the rod 66 downwardly. Therefore, when the head 20 is moving upwardly the rod 66 moves downwardly. However, the head 20 moves upwardly under control of the cam 92 during the time when the cam follower 88 is moving outwardly or away from the axis of the cam 92 as when it is moving onto the lobes 94 or 96. During this time the amplifiers 72 are moving counterclockwise about the cross pin 68 and operator member 112 carried adjacent to the right ends thereof presses downwardly on the valve plunger member 56. Also at this time the downward movement of the rod 66 moves the cross pin 68 down and therefore shifts the axis of the amplifiers 72.down. This partly cancels the effect produced on the valve plunger member 56 by the cam 92. The cancelling eifect produced by downward movement of the rod 66 and the cross pin 68 restricts the movement of the plunger 44 and in this way provides fine precise control, in the nature of a servo control, of the flow of fluid through the valve. By so providing the speed and reversal of movement of the head 20 are slowed and smoothened and the range of head movement is more limited than would otherwise be the case if the cam provided the whole means of control as described above. The modified movement is illustrated graphically in FIG. 6.

The operation is similar whether the head is moving up or down. When the head is moving down, however, the cam follower 88 is moving onto a lower spot on the cam 92 such as onto the spots 98 or 100. Movement of the cam follower 88 onto the lower spots 98 and 100 provides the basic pattern of downward movement of the head 20 and the radius of the low spots 98 and 100 relative to the cam axis determines how far down the head will move. The same is also true in a reverse sense for upward movement of the head 20. During downward movement, however, the rod 66 and the cross pin 68 move upwardly and shift the axis of the amplifiers 72 upwardly thereby cancelling in part the effect of the downward force on the member 56 produced bythe cam means. Thus the modifying effect on the. operation brought about by the connection with the head which shifts the cross pin 68 opposes the control action of the cam means in both directions and thereby reduces the movement of the plunger 44. g

In actual operation the cancelling effect of the movement of the rod 66 limits movement of the valve plunger 44 to a very small range of movement, and in so doing meters the flow of fluid to the master cylinder 28. This in turn slows the movement of the plunger 16 and causes the head 20 to move in a modified pattern as shown graphically in FIG. 6. The graph in FIG. 6, like the graph in FIG. 5, was also made during an actual operation of the device using the modifying control feature. With the modifying feature in operation, the head move ment was extremely smooth and even, almost as if the head floated during its cycling, and there was very little, if any, machine vibration. When the modifying control was not used, however, the strokes were longer and not as regular and the operation was choppy with considerable vibration and noise and the device was not easy to adjust to difierent conditions.

It is also to be noted in the graph of FIG. 6 that the head moves upwardly to its highest point on alternate strokes and likewise moves downwardly to its lowest point on alternate strokes. In between these extremes, the head 20 moves over shorter length strokes defined by the intermediate peak and valley of the cam. In terms of a honing operation, this means that the stone will project outwardly substantially from each end of a hole being honed on alternate strokes and will remain substantially entirely in the hole all of the rest of the time between these extremes.

During the actual machine tests it was observed that the valve plunger 56 moves over a range of about /2 to /4 of an inch when operated by the cam without the modifying means. When the modifying means were also operated, however, using the same valve, the valve plunger 56 moved over a range that was so small that its movement was almost undetectable. The particular control valve 40 that was used had the lands 46 and 4-3 of such size and spacing that in one position of the plunger 44 the lands just closed both outlet ports 34 and 38. This construction of the valve makes the valve operate like a servo mechanism and enables the valves to be adjusted to meter the flow to the master cylinder 28 to provide almost any operating condition.

As noted above the rod 102 is threaded at its lower end at 106 to provide a threaded connection with the cross arm 62. This is done to enable the head 20 to be adjusted so that it can stroke at different selected elevations. For example, increasing the length of the rod 162 between the head 20 and the cross arm 62 has the etfect of shifting the position of operation of the head so that it moves over a range at a higher elevation. This adjustment, however, does not change the length or the pattern of the strokes. By the same token, if the rod 102 length is decreased the honing elevation is shifted downwardly.

Another adjustment means is also provided for increasing and decreasing the lengths of the strokes. This is accomplished by moving the lower end of the rod 66 and the cross-pin 68 in the grooves 70. This can be done by a device, such as fluid motor 114 (FIG. 2) which has a horizontally movable plunger 116 which carries a plate 113. The plate 118 has a vertical groove 120 which cooperates with an extended portion of the pin 68. The motor 114 can be adjusted to have any desired plunger extension in order to adjust the position of the pin 68 in the grooves 70. For example, if the pin 68 is near the left end of the grooves 70 (FIG. 1) the rod 66 will have its greatest motion restricting effect and as a result the strokes will be relatively short. On the other hand, if the pin 68 is near the right end of the grooves 70 (FIG. 3), the rod 66 will have its least eifect and the strokes will be longer.

The length of the stone to the depth of the hole also plays a part in the accuracy of the honing operation. In the usual honing operation, the length of the stone is selected to be diiferent from the depth of the hole. It the Stone is longer than the hole depth (FIG. 8), the relationship of stone length to hole depth is usually held at or near a ratio of approximately 3 to 2. If, on the other hand, the stone is to be shorter than the hole depth (FIG. 7), a ratio of stone length to hole depth is selected to be at or near a ratio of approximately 2 to 3. These ratios are subject to -wide variance depending upon special circumstances but are included here for illustrative purposes and because they provide good results in most cases.

Extending to the right in FIGS. 7 and 8 is illustrated in dotted outline the pattern of vertical movement of the stone in the hole during a honing operation. In the position identified by the number 1, the stone is in its uppermost position corresponding to cam position 94 on the cam in FIG. 4. In this position approximately half of the stone extends out of the hole. In position 2 the stone has moved downwardly to a position substantially entirely inside of the hole and adjacent to the lower edge of the hole. This corresponds to earn position 100. Position 3 shows the stone after having moved upwardly to a lesser peak position with the stone still substantially entirely in the hole but positioned adjacent to the upper edge of the hole. This corresponds to cam position 96. Position 4 shows the stone in its downward most position with about half of its length extending out from the lower end of the hole and corresponds to cam position 98. Between positions 4 and 1 the stone again moves to its uppermost position. It is particularly important to note in connection with FIGS. 7 and 8 that during a substantial portion of the full honing cycle the stone is almost entirely inside the hole and that even during the relatively short intervals when the stone projects from the ends of the hole at least half of the stone remains in contact with the hole. This is important to the present device because the greater the contact time between the stone and the hole the greater is the efficiency and the shorter is the honing time.

The same or similar advantages are also obtained when the stone is selected longer than the hole depth as illustrated in FIG. 8. In both situations (FIGS. 8 and 7) the entire stone and hole surfaces are in contact with each other approximately equal amounts of time. This means that there will be approximately equal wear of stone and surface thereby contributing to the accuracy of the honing and also prolonging the usable life of the stones.

In FIG. 10 is shown a variation of the stroking pattern using a different cam. This is included to illustrate one of many possible variations that can be made in the device. The modified stroke pattern of FIG. 10 is particularly adaptable for use in a hole formed in a work piece that is made of two different materials of different hardness. In FIG. 10 the upper material identified as W1 is relatively harder than the lower material W2 and therefore requires more honing to produce an accurate surface. Notice that the harder material in the upper layer W1 undergoes about twice as much honing as the softer material in the lower layer.

Obviously, many other variations of the stroke pattern and of the shapes of the cam could be included to illustrate the invention. It is believed however, that the illustrations shown herein are sufficient for purposes of describing the invention and will enable those having ordinary skill in the art to design other cams and other varations, modifications and changes in the invention.

Thus it is apparent that there has been shown and described novel stroking means which fulfill all of the objects and advantages sought therefor, said device comprising means for controlling the pattern of movement of a member, such as a rotating honing member, and other means modifying said movement to provide a smooth and fully adjustable operating condition.

Obviously many changes, alterations, modifications and adaptions of the present device could be made by those skilled in the art without departing from the spirit and scope of the invention. All such changes, alterations, modifications and adaptions which do not depart from the spirit and scope of the invention are deemed to be covered by the present invention which is limited only by the claims which follow.

In the claims:

1. Means for stroking a member comprising a movable member, motor means connected to said member, means connected to the motor means for reversibly operating said motor means to reversibly move said member, said last named means including control valve means, cam means operatively connected to the control valve means, and other means attached to the movable member and operatively connected to the control valve means to partially neutralize the efiect thereon produced by the cam means.

2. A device for stroking a member comprising a movable member, fluid motor means connected to said memher, control means associated with said motor means including means for reversibly operating said motor means to alternately move the movable member in opposite directions, said control means including a source of fluid pressure, a control valve connected between said source and said motor means, movable plunger means in said valve for alternately directing fluid from the source to different locations on the motor means, and means engaged with said plunger means for controlling the positioning thereof in said valve, said last named means including cam means and drive means therefor.

3. The stroking device defined in claim 2 wherein a connection is provided between the member being stroked and the plunger means, said connection transmitting forces produced by the movement of the movable member to the plunger member, said forces opposing the controlling action of the cam means to partially restrict the flow of fluid from the source to the motor means.

4. Means for controlling the movement of a member comprising a movable member, reversible motor means connected to said member and capable of moving said member alternately in opposite directions, and control means for said motor means, said control means including control valve means connected to said mot-or means for controlling the speed and direction of movement thereof, cam means operatively connected to the valve means for controlling the operation thereof, and servo means connected between the movable member and the cam means for modifying the eflect of said cam means on the control valve means.

5. Means for controlling the movement of a movable member comprising a movable member, fluid motor means one member of which is connected to the movable member, and means for controlling the direction and speed of movement of said one member of said motor means, said last named means including a source of fluid pressure connected to the motor means and means for metering the flow of fluid pressure from said source to the motor means, said metering means including valve means and motor operated cam means for controlling the operation of said valve means to meter fluid flow to the motor means, and means connected between said valve means and said movable member to partially neutralize the effect of the cam means on the valve means.

6. Means for stroking a movable member comprising a movable member, fluid motor means connected to said movable member, a source of pressure fluid connected to the motor means, valve means connected between said source and said motor means, and means for controlling the valve means to regulate fluid flow between the source and the motor means so that the motor means alternately moves the movable member in opposite directions to produce a preselected stroke pattern therefor, said last named means comprising a movable valve control plunger in said valve means, a pivoted operator member pivotal on a pivot axis and engaged with said plunger, means operatively connected to said operator member for pivoting said member about said pivot axis to thereby change the position of the plunger in the valve means and hence to control fluid flow between the source and the motor means and other means connected between the movable member and the pivot axis, said last named means responding to the movement of the movable member to shift the position of the pivot axis in a direction to partially overcome the effect produced on the valve plunger by the pivoted operator member.

7. The means for stroking a movable member defined in claim 6 wherein preset means are provided for adjusting the position of the pivot axis of the operator member.

8. Means for stroking a movable member comprising a movable member, fluid motor means connected to said movable member, a source of pressure fluid, means including valve means connected between said source and at least two positions on the motor means, said valve means including means for alternately communicating said source to each of said positions on the valve means, and means for controlling the movement of said last named means on said valve means to affect changes in the direction of movement of the motor means to stroke the movable member in a preselected stroke pattern, said control means comprising an operator member engaged with said valve means, pivot means providing an axis about which said oeprator member rotates, cam means operatively connected to said operator member for pivoting said member about said axis whereby said valve means alternately communicates the source with a different one of said positions on said motor means, and means connected between the movable member and the pivot means, said last named means shifting the location of the pivot means in response to movement of the movable member in a direction to minimize the communication between the source and the motor means produced by the action of the cam means.

9. The means for stroking a movable member defined in claim 8 wherein adjustment means are provided in the connection between the movable member and the pivot means for adjusting the location of the movement of the movable member.

10. Means for reciprocating a movable member comprising a movable member, reversible motor means connected to the movable member, operator means for said motor means capable of alternately reversing the direction of movement of said motor means to thereby reverse the direction of movement of the movable member, and means connected between the movable member and the operator means and responsive to the speed and direction of movement of the movable member to partially neutralize the effect on the motor means of the operator means.

11. The means for reciprocating a movable member defined in claim 10 wherein said operator means includes a rotating cam member having a cam surface thereon and a follower member engaged with said cam surface, said cam surface having high and low portions corresponding to positions where the movable member reverses the direction of its movement.

References Cited in the file of this patent UNITED STATES PATENTS 2,102,007 Kimball Dec. 14, 1937 2,346,418 Dodson Apr. 11, 1944 2,404,849 Kimball July 30, 1946

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