US3695362A

US3695362A - Automatic setting motion-sensing control device

Info

Publication number: US3695362A
Application number: US45290A
Authority: US
Inventors: Frederick C Clarkson Jr
Original assignee: General Motors Corp
Current assignee: Motors Liquidation Co
Priority date: 1970-06-11
Filing date: 1970-06-11
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: CA935052A

Abstract

An automatic setting motion-sensing control device in the form of a sensing air valve which closes and sets its initial measurement point upon engagement with a workpiece and then opens upon a predetermined movement of the workpiece, relieving air pressure in the line. The resultant pressure drop is picked up by a pneumatic relay to stop the operation of a motion causing device operating on the workpiece.

Description

United States Patent Clarkson, Jr.

[ AUTOMATIC SETTING MOTION-' SENSING CONTROL DEVICE [72] lnventorz Frederick C. Clarkson, Jr., Niagaraon-the-Lake, Ontario, Canada [451 Oct. 3, 1972 Primary Examiner-Ernest R. Purser Attorney-Jean L. Carpenter and Arthur N. Krein [57] ABSTRACT An automatic setting motion-sensing control device in the form of a sensing air valve which closes and sets its initial measurement point upon engagement with a workpiece and then opens upon a predetermined movement of the workpiece, relieving air pressure in the line. The resultant pressure drop is picked up by a pneumatic relay to stop the operation of a motion causing device operating on the workpiece.

3 Claims, 3 Drawing Figures SUPPLY l AUTOMATIC SETTING MOTION-SENSING CONTROL DEVICE This invention relates to fluid actuated tools and, more particularly to an automatic setting motionsensing control device for a fluid actuated nut driver or similar device. More specifically, this invention relates to an automatic setting motion-sensing control valve for use with an rotary tool for arresting the motor which imparts torque to-a' wrench, screwdriver or other element coming in direct engagement with a bolt, screw, nut or the like.

It is well known to utilize rotary impact tools for installing or removing nuts, screws or bolts. Such rotary tools are equipped with motors which rotat'e an anvil or shaft serving as a means of supporting a wrench or screwdriver and for imparting thereto torque necessary to install a screw, bolt, nut or the like. It is also known to provide such tools with devices which automatically arrest the motor after a predetermined interval of time or in response to a predetermined resistance which the screw, bolt or nut offers to further rotation of the anvil.

It has been foundthat such control devices cannot always insure satisfactory application of these fasteners due to part tolerances of the overall structure on which these fasteners are to beused. r

For example, in the automotive industry, these rotary tools are used'either singly or in muIti-tool arrangements to drive the nuts which secure rocker arms in position on an internal combustion engine. In such an engine, valve lashing specifications may be stated in terms of the number of turns of the rocker arm ball stud nut from a zero lash position, a position at which all slack is taken up in the valve train, camshaft to valve tip, of the engine. Due to part tolerance of all items involved, these nut locations for the zero lash position varies more than the allowable lashing specification for the particular engine. Because of this, the prior known art devices to arrest the motion of a rotary tool would not be satisfactory for use in automatically installing the rocker arm ball stud nuts to retain rocker arms on an internal combustion engine.

Accordingly, it is an object of this invention to improve control devices whereby to provide an automatic setting motion-sensing control device to control the operation of a rotary tool, or similar device.

Another object of this invention is to provide a control device for the motor of a rotary tool, whereby the control device is automatically set to sense motion and thereby control the operation of the motor of the rotary tool.-

These and other objects of the invention are obtained by means ofan automatic setting motion-sensing control device inthe form of a motion-sensing valve including a spool valve element which is operative with respect to a control registering sleeve to open or close an air passage through the valve assembly, the sleeve being movable to an initial measuring or null position when the rotary tool is moved into operative position in relation to a fastener and, whereby, as the fastener is I moved permitting relative movement of the sleeve with respect to the spool valve element, the valve will be opened to relieve the air pressure and through a suitable pneumatic relay and controls arrest the operation of the motor of the rotary tool.

For a better understanding of the invention, as well as other objects and further features thereof,

positioned out of engagement with the nut on the valve rocker amt; I

FIG. 2 is a view similar to part of FIG. 1 showing the automatic setting motion-sensing control device located at the measuring or null position of the valve; and,

FIG. 3 is a view similar to FIG. 2 showing the rocker arm in its fully lashed position with the control device sensing this position and opening to arrest operation of the rotary tool.

Referring to the drawings, there is shown for the purpose of illustration only, an automatic setting motionsensing control device used to control the operation of a pneumatic rotary tool in the form of a nut runner and its pneumatic circuit to control the operation of the nut runner for properly positioning the rocker arm retaining stud nut on an internal combustion engine. A single nut runner can be used as shown in FIG. 1 and moved relative to each rocker arm assembly of the engine or the nut runner shown can be merely one of a multiple unit nut runner assembly adapted to simultaneously secure all of the rocker arm assemblies for the intake valve and then for the discharge valve of the engine.

As shown in FIG. 1, the automatic setting motionsensing control device, hereinafter referred to as the sensing valve, generally designated 10, is mounted on a movable support arm 11 which holds a conventional rotary tool 12 having a drive shaft 13 with a socket l4 suitably secured at its lower end. Socket 14 has an internal dimension for fitting on andturning a nut, such as the rocker arm ballst'ud nut 15 threaded on the rocker arm support 16. The stud nut 15 and rocker arm support 16 are part of a valve actuating mechanism for an internal combustion engine and includes a rocker arm 17 which is pivotably mounted by rocker ball 18 on the rocker arm support 16 secured in the engine head 19. The rocker arm is disposed adjacent to a cooperating push rod 21 and the valve stem 22 of a valve, not shown. The valve is resiliently held in closed position by spring 23 and which is compressed between the upper wall of the engine head 19 and the shield 24 secured to the underside of valve retainer washer 25 secured to the upper end of the valve stem 22 in conventional manner.

The drive shaft 13 of the rotary tool 12 is driven by a rotary air motor 26 connected to a high pressure air supply 27 by means of passage 28, four-way double pilot operated power valve 31 and conduit 32. Power valve 31, a pneumatically controlled valve, is actuated by air delivered thereto in a controlled manner through passages 33 and 34, relay valve 35 and passage 36 to a source of relatively low pressure air as supplied by air regulator valve 37 which is connected by conduit 32a to the air supply 27. The operation of the relay valve 35 in turn is controlled by low pressure air as supplied to one end of this valve by passage 41, regulator valve 42 and passage 43 connected to conduit 32a, and at its other end by air supplied through conduit 36a controlled by flow control needle valve 44, passage 45 and flexible passage 46 which is connected at one end to the relay valve 35 and its other end to the sensing valve of the invention.

Referring now to the subject matter of the invention, the sensing valve 10 includes a mounting sleeve 51 secured to the underside of the apertured portion of support 11, the mounting sleeve 51 reciprocably supporting an outer sleeve 52 which telescopes over, the mounting sleeve and which is normally biased downward, as viewed in the drawings, by means of a spring 53 encircling the lower portion of the mounting sleeve and enclosed by the outer sleeve 52. Outer sleeve 52 is in turn supported on a control rod 54 by means of nut 55 and contact nut 56 secured to the lower threaded end of control rod 54 and by sleeve 58.

Control rod 54, which extends down through an aperture 57 in support 11, is positioned for reciprocable movement by the sleeve 58 encircling the control rod at its lower end with the bottom of the sleeve 58 in contact with outer sleeve 52 and by control registering sleeve 61 with a stop member 62 positioned therebetween, the sleeve 58 and control registering sleeve 61 being slideable supported in bearing 63 and sleeve 58 additionally journaled in bearing 64, both bearings being mounted in stepped bored portion of mounting sleeve 51.

Control registering sleeve 61 is positioned on the control rod 54 for limited axial movement with respect thereto by shoulder 65 on the control rod and by stop member 62 which abuts against the top of sleeve 58. A friction ring member 66 retained in mounting sleeve 51 by annular spacer 67 engages the control registering sleeve 61 to hold it against axial movement with respect to the control rod 54 except when it is moved downward by engagement against the shoulder 65 on the control rod or when it is moved upward by movement of the control rod 54 forcing the stop member 62 into engagement with the bottom of the control registering sleeve 61 to move it upward.

At its upper end, the control rod 54 is slideably received within a dust shield 68 positioned in a counterbored portion of dust retainer mounting plate 71 secured to the upper side of support 1 l.

The control rod 54 is provided with a central passage 72 connected to passage 46 to admit air under pressure to a point near the bottom of the control registering sleeve 61 whereat a radial extending passage 73 extends outward from the passage 72 at the undercut portion 74 of the control rod between the

land portions

75 and 76 to in effect form a spool valve on the control rod, the latter coacting with the lower end of the control registering sleeve 61 to effect closing of the valve as seen in FIG. 2 or opening of the valve to permit discharge of air therefrom as seen in FIGS. 1 and 3.

In operation, the sensing valve 10 using low pressure air controls the operation of relay valve 35 to in turn control the flow of medium pressure air used to actuate the control valve 31 used to regulate the flow of high pressure air to operate air motor 26; the relay valve 35 being normally positioned, as shown in FIG. 1, by low pressure air, for example, air at 4 to 6 pounds per square inch pressure, from passage 41 in communication with the right end of the relay valve 35, as seen in this same figure.

To initiate operation, the sensing valve is originally in the position shown in FIG. 1, with the spring 53 forcing the outer sleeve 52 downward to in turn pull the control rod 54 downward whereby the shoulder 65 thereon engages the control registering sleeve 61 to force it downward until the annular shoulder thereon engages the inward directed shoulder of spacer 67. In this position, the lower [and 76 of the spool valve portion of the control rod 54 projects below the control registering sleeve 61 to allow air to be discharged from passage 73. Air thus discharged from the spool valve portion of the control rod 54 is free to flow through the annular space between the outer periphery of the stop member 62 and the inner bearing surface of bearing 63 and down the longitudinal slots 77 in sleeve 58 for discharge through

suitable apertures

78 and 81, provided in the walls of mounting sleeve 51 and outer sleeve 52, respectively.

With the elements of the sensing valve 10 in the position as just described, the flow of medium pressure air from passage 36a, as controlled by control needle valve 44, is such that it will be immediately discharged through the now open sensing valve to atmosphere to prevent any buildup of pressure in passage 46 sufficient to actuate relay valve 35 from the position shown in FIG. 1. Thus, relay valve 35 is maintained in the position shown in FIG. 1 thereby directing medium pressure air, for example, air at 50 pounds per square inch pressure, to passage 34 to actuate control valve 31 to the position shown to block the flow of high pressure air from conduit 32 through passage 28 to the air motor 26.

The sensing valve 10 and impact tool 12 are then moved relative to the rocker arm assembly of the engine in any suitable manner, not shown, since it forms no part of the subject invention, to a positive stop position as shown in FIG. 2 relative to the engine head 19, for example, with the nut 15 engaged in socket 14 and the end of contact nut 56 in engagement with the valve retainer washer 25. As the sensing valve 10 is moved to this stop position, the contact nut 56 engages the area to be sensed, in this case, valve retainer washer 25, causing the control rod 54 to retract upward against the biasing action of spring 53 moving the outer sleeve 52, sleeve 58, stop member 62 and control registering sleeve 61 upward thereby locating the control registering sleeve 61 relative to the valve retainer washer and fixing the initial measuring or null position with respect to this valve assembly of the engine. The control registering sleeve 61 is them held in this position by the friction ring member 66.

At the same time as the control rod 54 is moved upward, the lower land 76 thereon is moved upward into the control registering sleeve 61 blocking the discharge of air from radial passage 73. As this occurs, air pressure in passage 46 will immediately build up sufficiently to overcome the air pressure acting on relay valve 35 from passage 41, to shift the spool of this relay valve 35 to the right, with reference to FIG. 1, to place passage 36 in communication with passage 33 while venting passage 34 to atmosphere. This will now cause the spool of control valve 31 to move to the right, with reference to FIG. 1, to place conduit 32 in communication with passage 28 to initiate operation of air motor of valve stem 22 is followed by downward movement of lo control rod 54, biased downward by spring 53. After a predetermined movement downward, as controlled by the previously described setting of control registering sleeve 61, the lower land 76 on control rod 54 will emerge from the control registering sleeve 61, as seen in FIG. 3, to again allowthe discharge of air from the radial passage 73 in control rod 54. As this occurs, air pressure in passage 46 will be immediately reduced to allow the higher air pressure in passage 41 to again shift the spool of relay valve 35 to the left, to the position shown in FIG. 1, thus connecting the medium air pressure passage 36 to passage 34 to shift the spool of control valve 31 to the left, to the position shown in FIG. 1, blocking the flow of. high pressure air from conduit 43 to the air motor 26, while at the same time,connecting the passage 28 from air motor to exhaust through control valve 31, thus arresting the operation of the air motor.

After a valve lashing operation as just described, the rotary impact tool 12 and sensing valve are again moved relative to the engine to the position shown in F 1G. 1 at which time the spring 53 acting on the outer sleeve 52 will again bias the control rod 54 downward so that the shoulder 65 thereon will engage the control registering sleeve 61 to move it downward to the position shown in this figure so that the sensing valve is again positioned to measure an initial measuring or null position on the next valve and rocker arm assembly to beacted upon. i

To prevent any possible undesired buildup of back pressure within the sensing valve structure, the stop member 62 is provided at its upper surface with radial extending grooves 62aincommunication with the annular space between the stop member and bearing 63, while the space between the control rod 54 and the annular spacer 67 is vented toatmosphere by a radial passage 83 and annular groove 84 in annular spacer 67 and a radial passage 85 in mounting sleeve 51.

With the structure disclosed, operation of an air motor or similar device, as desired, can be accurately controlled by sensing and setting the control registering sleeve at an initial measuring or null position, with operation of the system then controlled by the predetermined relative position of the lands and undercut portion of the control rod, which with the control registering sleeve forms a spool valve control struc ture, I

What is claimed is: 1. A rotary impact pneumatic tool control circuit, in combination, a rotary air motor, conduit means including control valve means connected to said rotary air in which said rotary air motor is operable by pressurized aeriform fluid, relay valve means operatively connected to said control valve means and connectable to a source of pressurized aeriform fluid, said relay valve means being movable between a first position to effect movement of said control valve means to said initial arresting position and a second position to move said control valve means to said non-arresting position, and an automatic setting motion-sensing control device having valve means operatively connected to said relay valve means and connectable to a source of pressurized aeriform fluid, said valve means being adapted to be closed and set at an initial measuring point upon engagement with a workpiece and to open upon a predetermined movement of a workpiece to effect movement of said relay valve means to said second position and then to said first position.

2. A rotary impact pneumatic tool control circuit according to claim 1 wherein said valve means of said automatic setting motion-sensing control device includes a valve housing, a valve control sleeve slideably journaled in said valve housing, a control rod slideably journaled in said valve housing and slideably received in said valve control sleeve for limited axial movement with respect thereto and to effect movement of said valve control sleeve in opposite directions, with one end of said control rod extending from said valve housing for engagement with a workpiece, said control rod including a spool valve portion adapted to cooperate with said valve control sleeve between an open and closed position with respect thereto, and passage means therein in communication with said spool valve portion and connectable to a source of pressurized aeriform fluid, friction means engaging said valve control sleeve and bias means connected to said control rod to normally bias said control rod in one direction whereby said spool valve portion is in an open position with respect to said valve control sleeve.

3. In a rotary impact pneumatic tool control circuit, in combination, a rotary motor, conduit means includ ing control valve means connected to said rotary air motor and being connectable to a source of aeriform fluid under pressure, said control valve means being movable between an initial arresting position in which said rotary air motor is arrested and a non-arresting position in which said rotary air motor is supplied with aeriform fluid under pressure to be operable, relay valve means operatively connected to said control valve means and to a source of aeriform fluid under pressure, said relay valve means being movable between a first position to effect movement of said control valve means to said initial arresting position and to a second position to move said control valve means to said non-arresting position, and an automatic setting motion-sensing control device including sliding valve means connected to said source of aeriform fluid under pressure to regulate the flow of aeriform fluid to said relay valve means, said automatic setting motionsensing control device including valve housing means, a valve control sleeve and spacer sleeve means slideably journaled in said valve housing means, friction means normally retaining said valve control sleeve against sliding movement, said sliding valve means being journaled in said valve housing means with at least one end thereof extending from said valve housing for engagement of said spacer sleeve means into engagement with said valve control means to effect movement thereof in a second direction when said sliding valve means is moved to said valve closed position, and bias means connected to said valve housing means and to said sliding valve means to normally bias the sliding valve means to said valve open position to efiect movement of said relay valve means to said first position.

it: =0: 1: r

Claims

1. A rotary impact pneumatic tool control circuit, in combination, a rotary air motor, conduit means including control valve means connected to said rotary air motor and connectable to a source of aeriform fluid under pressure, said control valve means being movable between an initial arresting position in which said rotary air motor is arrested and a non-arresting position in which said rotary air motor is operable by pressurized aeriform fluid, relay valve means operatively connected to said control valve means and connectable to a source of pressurized aeriform fluid, said relay valve means being movable between a first position to effect movement of said control valve means to said initial arresting position and a second position to move said control valve means to said nonarresting position, and an automatic setting motion-sensing control device having valve means operatively connected to said relay valve means and connectable to a source of pressurized aeriform fluid, said valve means being adapted to be closed and set at an initial measuring point upon engagement with a workpiece and to open upon a predetermined movement of a workpiece to effect movement of said relay valve means to said second position and then to said first position.

3. In a rotary impact pneumatic tool control circuit, in combination, a rotary motor, conduit means including control valve means connected to said rotary air motor and being connectable to a source of aeriform fluid under pressure, said control valve means being movable between an initial arresting position in which said rotary air motor is arrested and a non-arresting position in which said rotary air motor is supplied with aeriform fluid under pressure to be operable, relay valve means operatively connected to said control valve means and to a source of aeriform fluid under pressure, said relay valve means being movable between a first position to effect movement of said control valve means to said initial arresting position and to a second position to move said control valve means to said non-arresting position, and an automatic setting motion-sensing control device including sliding valve means connected to said source of aeriform fluid under pressure to regulate the flow of aeriform fluid to said relay valve means, said automatic setting motion-sensing control device including valve housing means, a valve control sleeve and spacer sleeve means slideably journaled in said valve housing means, friction means normally retaining said valve control sleeve against sliding movement, said sliding valve means being journaled in said valve housing means with at least one end thereof extending from said valve housing for engagement with a workpiece, said sliding valve means being slideably received in said valve control sleeve for movement relative thereto between a valve open position and a valve closed position, said sliding valve means including means for engagement with said valve control sleeve for moving said valve control sleeve in a first direction when said sliding valve means is moved to said valve open position, said sliding valve means being secured to said spacer sleeve means to effect movement of said spacer sleeve means into engagement with said valve control means to effect movement thereof in a second direction when said sliding valve means is moved to said valve closed position, and bias means connected to said valve housing means and to said sliding valve means to normally bias the sliding valve means to said valve open position to effect movement of said relay valve means to said first position.