US2560366A - Clamping device for force responsive elements - Google Patents

Description

y 1951 H... E. OWEN 2,560,366

CLAMPING DEVICE FOR FORCE RESPONSIVE ELEMENTS Filed Dec. 30, 1947 Patented July 10, 1951 CLAMPIN G DEVICE FOR FORCE RESPONSIVE ELEMENTS Herbert E. Owen, Tulsa, Okla., assignor to Standard Oil Development Company, a corporation of Delaware- Application December 30, 1947, Serial No. 794,617

1 Claim. 1

The present invention is directed to devices utilizing a mass included in a moving system responsive to a force to be measured. In particular the invention relates to a clamping mechanism for holding said mass stationary when the system is not in operation and for the operation of the clamping mechanism from a remote position. The invention is of special application in the design of underwater gravity meters.

In systems of the general type referred to above, such as gravity meters, seismic pickups, and the like, a mass is suspended as freely as possible in a moving system and means are provided for measuring the movement of the mass in response to a force to be measured. These systems are necessarily of an extremely delicate nature if they are to possess the desired sensitivity. Consequently said systems cannot be transported safely unless some means is provided for clamping the moving system in a stationary position during transportation. As used in underwater prospecting it is necessary that means be available to, operate the clamping mechanism remotely.

The principal object of the present invention is the provision of a clamping means fora system of the type described which is simple, positive in action, and remotely operated.

An additional object of the present invention is the provision in a clamping system of the type referred to of means for positively preventing any adhesion of the mass to the clamping members when the latter are released. This is an important feature because in such systems the movement of the mass is slight and accordingly the space between the mass and the clamping members when the latter are in unclamped position is quite small. Under these circumstances when the clamp is operated to release the mass there is a tendency for the mass to cling to the clamping members.

In accordance with my invention electrical motor means are employed to rotate a screw which is operative to clamp or unclamp the mass of a moving system. A particular feature of my invention is the use of a friction clutch to couple the motor to the rotatable screw. By virtue of this provision when the clamped or unclamped position of the screw is reached the clutch will slip sufiiciently to release any undue tension on the parts, while at the same time the added current required to drive the motor will indicate that the mass is either clamped or unclamped.

My invention will be more fully understood from the following detailed description of the accompanying drawing in which an embodiment of my invention is shown in elevation, partly in cross-sectional detail. The embodiment shown relates to a gravity meter. Referring to the drawing the numeral 30 designates a water-tight housing which contains the gravity meter to permit lowering of the meter to the bottom of a body of water. Fixed to the bottom of the housing 30 is a standard 2 at the top of which is a cross member 3 having an upwardly inclined portion 4 at the end of which is carried a plate 5 having a vertical section substantially corresponding to 3 sides of an octagon with one of these sides in a horizontal position. Through each of the inclined sides of the octagon is screwed a pair of screws 6 spaced in symmetrical position to each other. Pivoted on the standardz is a bar I having one of its ends extending beneath the screws 6 and having its other end extending in the other direction from the pivot in such a way as to bear against an adjusting screw 8 screwed into the cross member 3.

The mass which is to be clamped is designated by numeral 9 and is arranged between the screws 6 and the bar 1 in such a way that the bar 1 can contact it symmetrically with respect to the screws 6. Further details of the gravity meter are not included herein as they form no part of the present invention. As may be seen from the drawing, the adjusting screw 8 is arranged for release of bar I by rotation counter-clockwise, and is provided with a thread I 6 of steep pitch so that a small rotative movement results in a relatively long longitudinal movement. The thread is conveniently chosen so that one half revolution of the screw 8 will be sufiicient to completely clamp or unclamp the mass 9. Fixed to the screw 8 are two extensions l8, apart, both adapted to contact lug [9, one at the clamped position of the bar 1 and the other when the mass 9 is completely unclamped by the same bar 1. Con tact of the extension l8 and the lug I9 will cor- .respond in one position to the unclamped position of the bar I and will correspond in the other position to the clamped position of the bar 1.

Extending from the end of the mass 9 is a pin or lug l3. This pin may be threaded into the mass 9 or may be suitably clamped to the mass. It extends outwardly from the mass for a small distance, for example about a quarter of an inch. Horizontally extending from the standard 2 are two resilient spring wires 2! and 22. These wires are so positioned that when the mass 9 is unclamped no contact is made with the pin l3. In the clamped position, however, pin I3 is caused to press against the upper wire 2| exerting a flexing force on the wire. On release of the clamping mechanism, therefore, the wire exerts a positive force on the pin 13 and the mass 9, forcing the mass free from the upper clamping members to prevent its adhering thereto. Similarly, release of the clamping mechanism permitting the mass 9 to drop downwardly away from the upper clamp causes the pin I3 to contact the lower wire 22 which exerts a positive upward push to free the mass 9 in the event it tends to adhere to the lower clamping bar 1.

Positioned in the housing above the gravity meter is a D. C. motor 35. This motor and the associated parts to be described, may conveniently be mounted to a plate 36 which may serve as a cover for the gravity meter. The motor 35 is suitably geared to turn at a slow rate of speed; a speed of approximately R. P. M. is suitable. Attached to the shaft of the motor is a conical drive 31 which contacts a similar conical drive 39 which is positioned onthe shaft I4. Contact between the conical drives is maintained by the pressure exerted by the fiat spring 39 which bears against the end of the shaft 4|]. The shaft 40 is coupled to the rotatable screw 8 through a socket joint 4| which may be of the type shown. Longitudinal movement of the screw 8 as it is rotated is accommodated within the socket 4| without altering the position of the conical drive 38. A suitable bearing 42 is employed to support the shaft 40 as It passes through the metal plate 35. Insulated electrical conductors for the operation of the motor 35 are carried to the surface of the water through the packing joint 45 of the housing 39. Positioned remotely, for control purposes, is a source of voltage 45, an ammeter 41, and a double throw switch 48. The electrical conductors from the motor are connected to four of the poles of the double throw switch so that the switch acts as a reversing switch. The central elements of the switch 48 are connected to the other side of the switch will be used for clamping the mechanism. On closing the switch to the unclamping position at a time when the mechanism is clamped, the motor will be caused to rotate in such a direction as to permit the screw 8 to release the clamping mechanism. Rotation of the screw 8 will be continued until the extension [8 has contacted the lug I9. At this instant,'the clutch members 31 and 38 will begin to slip on each other causing an increase in the current drain of the motor. This will be indicated as a surge of current on the ammeter 41 and will instruct the operator that the desired operation has been completed and the switch 48 may then be opened. Similarly, when it is desired to clamp the mechanism the switch 48 will be thrown in the opposite position, causing the motor to rotate in a reverse direction until the clamping mechanism is closed. Complete closure of the clamping mechanism will again be indicated by a surge of current responsive to the slipping of the clutch members. The conical clutch members may be constructed of any desired material. For example, they may be made of wood, plastic, leather or metal. However, it is preferred that one of the conical drives be composed of leather, or be leather covered, while the other drive is preferably a metallic surface which has been knurled.

Having now fully described my invention, I claim-- A remotely controlled clamping device for a force measuring instrument including a forceresponsive element capable of suspension for response to said force, which comprises a first clamping member carrying a plurality of clamping points, and a second clamping member carrying at least one clamping point arranged symmetrically in respect to said plurality of clamping points, said plurality of clamping points and said single point being arranged on opposite sides of a portion of said force responsive element, at least one of said clamping members being movable with respect to the other clamping member so as to place said force-responsive element in a clamped position and in a non-clamped or normal operative position, a pin-like projection on said force-responsive element, a pair of resilient wires held by said instrument on either side of said projection, one of said resilient wires engaging said projection when said force-responsive element is in a clamped position, the other of said resilient wires engaging said projection when said force-responsive element travels beyond its normal operative position in a direction away from said first named resilient wire, both of said wires being free of said projection when said force-responsive element is in its normal operative position, rotatable means for adjusting the relative positions of said clamping members so as to place them in clamping and non-clamping positions as desired, an electric motor having a 'rotatable shaft, friction clutch means coupling said rotatable shaft to said rotatable adjusting means, and an electrical circuit feeding said motor and provided with an ammeter positioned in said circuit, whereby slippage of said clutch will be indicated by increased current readings of said ammeter.

HERBERT E. OWEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,449,458 Sutermeister Mar. 27, 1923 1,876,658 Fox Sept. 1932 1,979,340 Norman Nov. 6, 1934 2,349,404 Blair et al. May 23, 1944 2,384,739 Hasbrook Sept. 11, 1945

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