US20030138289A1

US20030138289A1 - Spherical locking device

Info

Publication number: US20030138289A1
Application number: US10/340,128
Authority: US
Inventors: Stephen Ronsheim
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-01-22
Filing date: 2003-01-10
Publication date: 2003-07-24
Also published as: AU2003209309A1; US6641323B2; US20030138288A1

Abstract

A cylindrical body has a first part-spherical socket portion in the top, fittingly receiving a ball. A ball retainer has a second part-spherical socket portion facing the first part-spherical socket portion and receiving the ball therein. A post has a proximal end fixed to the ball and extends radially outward from the ball and away from the body to a distal end, and has screw threads at the distal end to receive a fastener thereon for attachment of an object to the distal end of the post. The ball-in-socket mounting of the post enables freely swiveling the ball and thereby the swiveling the distal end of the post to an infinite number of loci in a spherical envelope centered at the center of the ball, as well as enabling the post, and any object mounted to the post, to be rotated on a radial line from the center of the ball to the location of mounting of the object to the post.

The body has a cylinder in the bottom receiving a piston. The piston is connected to the ball retainer for clamping the retainer on the ball and thereby locking the ball in the socket portions, to lock the post and thereby the object mounted to the post, in a position and orientation in space as selected by the user. Different embodiments employ various combinations of fluid pressure and mechanical springs to lock and unlock the device. In one example, a hydraulic pump assembly is coupled to the body to apply and release pressure on the piston.

Description

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part patent application based on parent application Ser. No. 10/054,046, filed Jan. 22, 2002.[0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to holding devices for objects, and more particularly to a device for holding a workpiece or other object, or for holding another workpiece holding device, in any of a variety of positions and orientations for as long as desired.

2. Description of the Prior Art

In many industries, professions, and crafts, it is essential to hold an object stationary in some selected position and orientation in space for viewing it, for viewing with it, or working on it, or somehow dealing with it. Clamps and vises are probably the most common holding devices for such purposes. But in many instances, they are not versatile enough to easily hold an object in exactly the attitude or orientation which the user needs or desires. The present invention is addressed to this problem.

SUMMARY OF THE INVENTION

Described briefly, according to various embodiments of the present invention, an object holding device includes a body having a first part-spherical socket portion fittingly receiving a ball. A ball clamp has a second part-spherical socket portion engaging the ball. An object mount on the ball extends in a direction away from the socket portions and from the body and has means thereon for attachment of an object to the ball.

The body has a cylinder therein receiving a piston forming two chambers in the body. The piston is connected to the clamp in such a way that, in three embodiments, when pressurized fluid is applied to one chamber, the piston moves the clamp socket portion tight against the ball, locking the ball in place. In a fourth embodiment, a spring normally clamps the clamp socket portion tight against the ball. Then, when fluid pressure is applied in the other chamber, the piston unclamps the clamp socket portion from the ball. Prior to application of locking force, an object fastened to the post can be moved by the user to a variety of locations and orientations in space and then, upon selecting a desired location and orientation for the object, the user locks the ball to hold the object in the selected position and orientation by application of fluid pressure to the one chamber (in three embodiments). In the fourth embodiment the user unlocks the ball by applying fluid pressure to overcome the clamp spring and, after moving the post to the desired position and orientation for the object, the user locks the ball by releasing the fluid pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the device according to a typical embodiment of the present invention. [0008]
FIG. 2 is a section therethrough taken at line [0009] 2-2 in FIG. 1 and viewed in the direction of the arrows.
FIG. 2A is an orthographic cut-away section of the device portion above the base and taken at line [0010] 2-2 in FIG. 1 and viewed in the direction of the arrows.
FIG. 3 is a bottom plan view of the device. [0011]
FIG. 4 is a section taken at line [0012] 4-4 in FIG. 2 and viewed in the direction of the arrows.
FIG. 5 is a section taken at line [0013] 5-5 in FIG. 1 and viewed in the direction of the arrows.
FIG. 6 is a view like FIG. 2 but adding a pump assembly for a self-contained closed system incorporating a locking device according to a typical embodiment of the present invention. [0014]
FIG. 7 is a fragmentary sectional view of a second embodiment like that of FIGS. [0015] 1-5 but adding a piston return bias spring.
FIG. 8 is a sectional view similar to that of FIG. 2 but showing a third embodiment in which the clamp piston is double acting. [0016]
FIG. 9 is a sectional view similar to that of FIG. 8 but showing a fourth embodiment in which there is a piston applying bias spring whereby the device is normally locked but can be unlocked by application of fluid pressure to the piston. [0017]
FIG. 10 is a top plan view of the embodiment of FIG. 7. [0018]
FIG. 11 is a sectional view taken at line [0019] 11-11 in FIG. 8 and viewed in the direction of the arrows.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates are intended to be protected. [0020]
Referring now to the drawings in detail, the illustrated embodiment includes a [0021] ball 11 received in a two-part socket including an upper socket portion in a clamping plate 12, and a lower socket portion in a body 13. The body has a generally cylindrical downwardly-opening cavity 15 extending downward to the bottom edge of the body. A generally-cylindrical piston assembly is received in the cavity and includes the seal retainer cap 16 secured to the piston 17 by a socket head cap screw 18, and capturing a piston seal 14 in the annular groove formed by the circular rib 17R atop the piston, and the underside of the cap 16. The inner edge of the rib 17R forms a recess which centers the seal retainer cap on the piston. As best shown in FIG. 4, the piston 17 is formed with three circularly-spaced arms 17A, each of which has a threaded aperture in it receiving the threaded lower end of a socket head shoulder bolt 21 which serves as a tie rod whose head is received in a recess in the top plate 12.
A [0022] base 20 is fastened to the bottom of the body by three, circularly-spaced socket-head cap screws 19. Four apertures 25 are provided in the corners of the base for easy attachment to a table or other support. It should be understood that the invention incorporating base 20 or other attachment device for it can be oriented and secured in any attitude and still function as desired. Also, a tapped port 13P is provided in the outer wall of the body 13 and communicates with a internal passageway 13T opening into the chamber portion of cavity 15 above the cap 16. Port 13P is provided to receive a fitting through which pressure can be introduced from an outside source. This is a fluid pressure and may be gaseous or hydraulic, but more likely hydraulic. This pressure may be applied by fluid admitted through a valve in a supply line from a factory pneumatic or hydraulic system (not shown), and released to sump or a return line by the same valve, for example. One of several alternatives is shown in FIG. 6. It connects the body 13 to become part of a small, self contained closed hydraulic system with a manually-operated pump assembly 30, including the pump, an accumulator, gauge, and valve to hold pressure, but operable when desired to release pressure from the clamp piston. Such pump assembly is readily available in the art. It can be purchased finished and can be connected to the locking device with a hose as shown, or can be directly connected to the port 13P. An example of such pump assembly is Model No. P-142 manufactured by Enerpac of Butler, Wisconsin.
A maximum possible spacing between the piston cap and the piston is established by the [0023] tie rod bolts 21. This spacing is such that there is a gap 12G between the bottom of clamp plate 12 and the top of the body 13 when the ball is resting in and supported by the lower socket, and the plate 12 is resting on and supported by the ball, as shown in the drawings. This gap is typically 0.020 inches. When there is no fluid pressure applied to the chamber above the piston in cavity 15, the piston assembly is suspended in the cavity by whatever friction there may be between the body and the piston and seal assembly. In the absence of pressure in the cavity, the limit to possible descent of the piston assembly is reached when the heads of the tie rods 21 seat on the bottom of their receiver recesses in the plate 12. At this time it is desirable that there be at least a little clearance space between the top of the piston seal retainer cap 16 and the downwardly facing top surface of the piston receiver cavity 15. Therefore, normally the socket portion of plate 12 is not tightly engaged with the ball, so that the ball can be swiveled rather freely, but preferably not loosely, in the lower and upper portions of the socket.
An object support is shown in the form of a [0024] post 23 screwed into a hole in the ball so that it is tight in the ball and projects from the ball and away from the body 13. It has an object receiver in the form of a threaded socket 23S at the top, by which an object to be positioned can be fastened with a bolt or a screw. This object can be a work-piece or a tool or another holding or clamping device or about anything that is to be positioned and held in a certain position in space with a certain orientation at that position. The object receiver can be a variety of devices other than a threaded socket. Also, the object support can be other than a solid post.
In use, either an object to be used or treated is fastened to the post, or some other holding device can be fastened to the post. When the user determines and moves the distal end of the post to the position desired for the object to be treated or used, whether the object is mounted directly to the post or to a holding device mounted to the post, the user can then apply pressure to the [0025] pressure port 13P by operating a valve on a pressure line or by operating the closed system pressure-applying pump. When the pressure is applied, the piston 17 is driven in a downward direction forcing the tie rod bolts to pull the plate 12 in a downward direction which clamps the upper socket portion onto the ball 11 and thereby clamps the ball into the lower socket portion. The clamping holds and locks the post securely in the selected attitude until the pressure is released. If there is a desire to lock the post in the selected attitude without concern about possible reduction or loss of fluid pressure during the passage of time, three auxiliary clamp screws 22 (typically socket head cap screws) shown dotted in the drawings, can be screwed into the body 13 to the extent that their heads seat on the bottom of their head-receiving recesses in plate 12, pulling the plate 12 toward body 13 and thereby mechanically supplementing the hydraulic clamping of the plate onto the ball and the ball onto the socket in the body 13. This will keep the ball locked, even if the pressure on the piston is released.
Various sizes of devices may be built according to my invention. Ball diameters of 1.75 inches, 3 inches and 5 inches currently seem desirable for most applications. Materials for fasteners are preferably steel. For the ball, post, body and piston, anodized aluminum works. The clamping plate might preferably be hardened steel. For the piston seal, a square cross section of “Teflon” brand material works. A pressure capability of up to 5000 pounds per square inch (psi) seems appropriate. The locking force of the plate on the ball will depend on the pressure applied and the area of the piston. A force of 15000 pounds can be achieved easily. Obviously many other materials and sizes and pressures may be chosen and used depending on the needs of the user. [0026]
The location of the post on the ball enables the post to swivel about the combination socket portions in a 360 degree circle and to rotate 360 degrees about any radius line from the center of the combination socket portions. The center of the ball is at the center of the socket portions when the ball is clamped. Even when the pressure is released from the piston, the ball continues to rest in the lower socket portion, and the upper socket portion will usually remain centered on the ball, so the center of the socket portions remains effectively the center of the ball. The user can move the object-fastening portion of the post in a conical space definable by a radial line from the center of the ball to the object-fastening portion of the post. When the user does this, the post can also be rotated about the radial line to thereby achieve not only the desired position of an attached object in space, but also the desired attitude of the object when in that position. It should be recognized that the means for mounting the object is not necessarily a post, as shown, or a straight member. Also, the apex angle of the conical volume which can be swept during swiveling will depend upon the size and shape of the opening in the top of the plate through which the object mount extends, and the size and shape of the object mount itself where it extends through the opening. [0027]
In the illustrated example where the [0028] opening 12C in plate 12 is round, and the post version of an object mount has a round portion at the opening, the sizes are selected so that the apex angle of the cone is preferably a minimum of 90 degrees. The dotted line 23A in FIG. 2 is an example of the limit of travel to the left side of the cone at 45 degrees from the vertical center line 40 of the assembly. A larger size opening 12C, or a lesser diameter of the post at the opening, would enable a wider apex angle of the possible sweep of the post.
One or more of the devices according to the present invention may be used together for additional articulation from a fixed attachment location to an ultimate position and orientation for the object or objects to be held and positioned. [0029]
Referring now to FIG. 7, most of the components therein are basically the same or very similar to those shown in FIG. 2, so will be given the same reference numerals as in FIG. 2. But the [0030] piston 35 is different in the respect that it has a centrally located, downwardly opening cavity 36 in the bottom receiving a piston bias return spring 37. The piston is also manufactured in one piece, in contrast to the two piece piston shown in FIG. 2.
The new feature of the return biasing spring assists in release of the clamp upon release of fluid pressure from the [0031] port 13T. This assistance overcomes any resistance of the seal 14 to return of the piston and the clamp to the ball releasing position, to restore the gap 12G between the clamp plate 12 and the body 13. The force applied by the spring 37 is relatively small, being no more than necessary to overcome the frictional resistance of the seal to the rise of the piston to an unclamping condition when the fluid pressure is released.
Referring now to FIG. 8, although many components are similar to those in the previously described figures, some have enough differences from those previously described that all will be given new reference numerals. This embodiment of the invention incorporates a ball and post as one [0032] piece 41 having the ball portion 41A and post portion 41B which is externally threaded at 41T. It is received in a part spherical socket 42 in body 43. It is trapped in the socket by the clamp plate 44. But as is true in the FIG. 7 embodiment, piston 46 has a centrally located, downwardly opening cavity 47 receiving a piston return bias spring 48. The clamp plate 44, like the body, piston, and return spring cavity is cylindrical and centered on the axis 49. The plate is secured to the piston by three circularly spaced tie bolts 51 in the same manner as in the previously described embodiments. However, in this embodiment, as could be done in the previously described embodiments and is shown in dashed lines in FIG. 10, three clamp lift springs 52 are circularly spaced around the axis 49 in the same manner as the auxiliary clamp screws 22 are located and spaced in the previously described embodiments. In the FIGS. 8 and 9 embodiments, clamp screws 22 are situated around the axis in a manner as shown in FIG. 10. Tie bolts 51 are situated in the same manner as are the tie bolts 21 in FIG. 10. It should be understood that clamp lift springs 52 can also be used in combination with auxiliary clamp screws such as 22 in the same locations, if desired.
The embodiment of FIG. 8 also includes the [0033] end cap portion 53 of the body fastened to the bottom of the body 43 by three circularly spaced cap screws 54 located as are the cap screws 19 in FIG. 2. A face seal ring 56 seals the body 43 to the body end cap portion 53.
In this embodiment, the body cavity is in the form of a stepped internal cylinder. The piston has a stepped external cylinder form. It does not have arms such as [0034] 17A in the FIG. 4 embodiment.
The piston has two seal rings on it. The [0035] lower seal ring 57 cooperates with the piston and lower portion of the bore in the body to form a lower chamber 58 under the piston. The upper seal ring 59 cooperates with the upper portion of the bore in the body to form an upper chamber 61. Threaded upper port A communicates with upper chamber 61. Lower threaded port B communicates with the lower chamber 58.
In operation, after the object mounted to the [0036] post 41B is situated by the user in the orientation and position desired, fluid pressure is applied in port A. The fluid may be a liquid or a gas, typically oil or air. The pressure will drive the piston down until the part spherical surface in the clamp plate 44 forces the ball tightly against the part spherical socket in the body 43, locking the post in the selected position. It will remain so locked until pressure is released.
To unclamp the ball, pressure is released from port A and introduced through port B, pushing the piston upward, thus moving the tie bolts upward with it. A slight assist is provided with the [0037] piston return spring 48 and the lift springs 52. As the tie bolts rise, they enable the clamp lift springs to push the clamp plate 44 upward and sufficiently away from the ball to enable freely moving the post to any other position desired. The upper limit of travel of the piston and thereby the tie bolts, is limited by engagement of the upper end of the piston with the upper end of the upper cylinder portion in the body or by the shoulders 62 of the piston with the step 63 in the cylinder wall of the body. This, will of course, limit the gap 44G between the bottom face of the clamp plate 44 and the top face of the body.
By providing the double acting cylinder arrangement, this device can be hooked up to a fluid pressure source through a selector valve to, in one valve position, pressurize one port and dump the other, for clamping the ball and, in another valve position, dump the one port and pressurize the other to enable unclamping. [0038]
Referring now to FIG. 9, many of the parts are the same as shown and described with reference to FIG. 8, so are given the same reference numerals. However, in this embodiment, the device is arranged to be normally clamped without the application of fluid pressure, and released only upon application of fluid pressure. In this embodiment, the centrally located upwardly opening cavity or [0039] pocket 66 in the piston 46 receives a piston clamping bias spring 67. This spring normally biases the piston downward so that the clamp plate 44 forces the ball tightly against the socket 42 in the body 43. In order to release the clamp plate, fluid pressure is applied in port B, applying sufficient pressure in chamber 58 to force the piston up and overcome the downward bias of spring 67 and thereby force the tie bolts upward, enabling the clamp lift springs 52 to raise the clamp plate 44 and re-establish the gap 44G, thus assuring that the clamp is sufficiently released from the ball to enable the user to freely move the post to another position. It will be understood, that the port A is not used for pressure application clamping in this embodiment. Also, although it is shown in this FIG. 9, the upper seal 59 is not needed.
In view of the foregoing, and while the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. [0040]

Claims

What is claimed is:

1. A device for holding an object at a selected position and orientation and comprising:

a ball;

a body having a part-spherical socket portion having a center of curvature and receiving said ball;

a cylinder in said body and having a cylindrical wall, the wall having a cylindrical axis on a line extending through the said center of curvature, and the cylinder opening in a direction away from the socket portion;

a piston received in said cylinder and forming a chamber;

the piston being moveable axially in said cylinder in directions toward and away from said socket portion;

a clamp spaced from said piston and having a part-spherical socket portion facing toward the part-spherical socket portion of said body and receiving the ball therein and operable to establish a ball to body clamped condition;

ties connected to the clamp and to the piston to prevent the spacing between the clamp and the piston from exceeding a predetermined limit;

a passageway communicating with the chamber for admitting pressurized fluid to enter the chamber to cause the piston to move along said axis in a direction relative to the socket portion of said body to enable a change in the ball to body condition

2. The device of claim 1 and further comprising:

a projection on the ball and adapted to connect to an object to be positioned and held in a selected position.

3. The device of claim 2 and wherein:

said projection is a post on the ball and which extends in a direction away from the socket portions and has means thereon for attachment of said object to the post.

4. The device of claim 1 and wherein:

said chamber is between said piston and said socket portion of said body.

5. The device of claim 1 and wherein:

said piston is between said socket portion and said chamber.

6. The device of claim 5 and wherein:

said piston has a proximal end and a distal end, and a recess in the proximal end; and

a spring is received in said proximal end and engages said body normally urging said piston in a first direction causing said ball to be clamped to said body.

7. The device of claim 6 and wherein:

one wall of said chamber is the proximal end of said piston whereby said piston is movable in a second direction opposite said first direction and against the urging of said spring to enable unclamping of said ball from said body.

8. The device of claim 7 and further comprising:

resilient members between said body and said clamp for biasing said clamp toward a ball unclamping condition.

9. The device of claim 8 and wherein:

said body and clamp have a plurality of facing circularly-spaced sockets receiving said members; and

said resilient members are lift springs.

10. The device of claim 1 and further comprising:

at least one resilient biasing device on said body and clamp and normally biasing said clamp toward a ball to body unclamped condition.

11. The device of claim 10 and further comprising:

a plurality of sockets in said body and a plurality of sockets in said clamp, the sockets of said plurality in said clamp facing the sockets of said plurality in said body; and

a plurality of said resilient biasing devices received in said facing sockets and biasing said clamp toward a ball to body unclamped condition.

12. The device of claim 11 and wherein:

said biasing devices are springs situated in an array of said facing sockets arranged in circularly spaced locations on a circle about said axis line.

13. The device of claim 1 and wherein:

said cylinder is stepped, having a first portion of one diameter and a second portion of another diameter;

said piston has first and second ends and is stepped, having a first portion of one diameter extending to the first end and a second portion of another diameter extending to the second end,

said chamber being at the first end,

and said piston forming a second chamber at said second end.

14. The device of claim 13 and further comprising:

a second passageway communicating with said second chamber for admitting pressurized fluid to enter said second chamber to cause the piston to move along said axis in a direction relative to the socket portion of said body to enable a change in the ball to body condition from clamped to unclamped.

15. The device of claim 14 and wherein:

said first and second ends of said piston are opposite ends;

said first and second chambers are located at said opposite ends of said piston whereby fluid pressure applied to said first end causes a ball to body clamped condition.

16. The device of claim 15 and wherein:

said first and second passageways are separate to enable double acting cylinder operation for alternate pressurization of said chambers and fluid powered selectable clamped and unclamped ball to body conditions.

17. A device for holding an object at a selected position and orientation and comprising:

a body having a part-spherical socket portion for receiving a member having a convex exterior face portion;

an object mounting member having first and second convex face portions, said first convex face portion being received in said socket portion of said body;

a cavity in the body, said cavity having a cylindrical wall, the wall being cylindrical about an axis, and the cavity having an open end remote from said socket portion of said body;

a piston received in the cylindrical wall of the body and co-operating with the cavity to form a chamber;

the piston being slidably received in the body and moveable in a direction toward and, alternatively, away from said socket portion of the body;

a clamp spaced from said piston and having a part-spherical socket portion facing toward the part-spherical socket portion of said body and receiving the said second convex face portion of said mounting member therein;

a passageway communicating with the chamber for admitting pressurized fluid to enter the chamber to cause the piston to move in a direction along said axis and thereby enable the clamp to move relative to said object mounting member to enable a change between a locked and unlocked condition of said object mounting member for a selected object position and orientation; and

a projection on the object mounting member and adapted to connect to the said object to be positioned and held.

18. The device of claim 17 and wherein:

said projection is a post on the mounting member and which extends in a direction away from the socket portions of said body and clamp and has means thereon for attachment of an object to the post.

19. The device of claim 17 and further comprising:

a pressurized fluid source coupled to said passageway and operable to apply fluid pressure to said chamber to lock said object mounting member, and to selectively enable reduction of fluid pressure from said passageway to enable unlocking of said object mounting member.

20. The device of claim 17 and further comprising:

a second cylindrical wall in said cavity and which is cylindrical about said axis;

said piston having a portion co-operating with said second wall to form a second chamber; and

a second passageway communicating with the second chamber for admitting pressurized fluid to enter said second chamber to cause the piston to move in a direction opposite the said direction of the piston movement causeable by pressurized fluid in the first-mentioned chamber.

21. The device of claim 17 and further comprising:

a closure at the open end of said cavity;

a downwardly opening cavity in said piston; and

a resilient member residing in said cavity in said piston and bearing on said piston and on said closure to bias said piston in a direction toward said socket portion of said body.

22. The device of claim 17 and further comprising:

an upwardly opening cavity in said piston.

23. The device of claim 22 and further comprising:

a resilient member residing in said upwardly opening cavity in said piston and bearing on said piston and said body and biasing said piston to move away from said socket portion of said body and thereby pull said clamp toward said socket portion of said body to normally lock said object mounting member to said body.

24. The device of claim 17 and further comprising:

at least one resilient biasing device situated between said clamp and said body to assist in a change from locked to unlocked condition of said object mounting member.

25. The device of claim 24 and further comprising:

a plurality of sockets in said body and a plurality of sockets in said clamp, the sockets of said plurality in said clamp facing the sockets of said plurality in said body and circularly spaced about said axis and receiving said at least one resilient biasing device and additional resilient biasing devices.

26. The device of claim 25 and wherein:

said resilient biasing devices are lift springs.

27. The device of claim 17 and wherein:

said cylindrical wall in said body is stepped, providing a cylinder having first and second diameter portions; and

said piston is stepped, having first and second diameter portions slidably received respectively, in said first and second diameter portions of said stepped cylinder.

28. The device of claim 27 and wherein:

said piston has first and second ends;

said body has an end cap portion,

said second end cooperating with the second diameter portion of said cylinder and with said body end cap portion to form a second chamber of said body.