Clamp and lock for paint mixer

A gyroscopic paint mixer having a ratcheting lead screw paint container clamp and lock with a pawl releasably engaging an axial relief in the lead screw. A clamping frame is driven by a shaft maintained in concentricity with a stationary ring gear by an antifriction bearing mounted between the shaft and ring gear. A support plate has a peripheral lip forming a first recess sized to position either a generally square paint container or a generally D-shaped paint container. The support plate has a second recess to position a cylindrical paint container concentric to a spin axis.

FIELD OF THE INVENTION

This invention is in the field of paint mixing machines, particularly gyroscopic and platform or orbital mixers.

BACKGROUND OF THE INVENTION

In the past, paint mixers of the gyroscopic and platform types used various clamping mechanisms to secure the paint container in the mixer. Such mechanisms typically required an operator to advance or retract a clamping pad or plate with respect to one end of the paint container or containers held for mixing. Furthermore, to retain the paint contaner securely, the clamp mechanism requires a lock to prevent unintentional release or slippage of such clamping mechanisms. Such clamping and locking mechanisms often were constructed of a number of parts needing alignment for proper operation, due in part to the separation of functions between the clamping parts and the locking parts, which nevertheless were required to work together. The relatively large number of parts on occasion caused relatively high friction in the mechanism, making it difficult for the operator to use the clamp and lock. Furthermore, the large number of parts added to the cost of manufacture and service.

SUMMARY OF THE INVENTION

The present invention, in one aspect, is directed to a simple and efficient combined clamp and lock mechanism in which certain parts are used simultaneously to both clamp and lock and are useful in gyroscopic and platform or orbital mixers. In this aspect, an apparatus and method are provided in which a lead screw with a helical thread has at least one axial relief is received in a collar secured to a clamping frame of the paint mixer and having a mating thread, and a pawl engages the axial relief of the lead screw permitting rotation of the lead screw in a first direction advancing into the collar and selectively preventing rotation of the lead screw in a second direction opposite to the first direction.

In another aspect, some prior art gyroscopic mixers had a rotating shaft projecting through a stationary gear, but did not have positive alignment between the center of the shaft and the center of the gear. The present invention overcomes this eccentricity of the prior art by providing a centering structure supporting the shaft which preferably is an antifriction bearing centered in the stationary gear and supporting the rotating shaft in concentric alignment with the gear such that a planetating gear orbit is concentric to a pitch circle of the ring gear.

In another aspect directed to a gyroscopic mixer of the type having a clamping frame including a pressure plate and a support plate in opposed relationship to clamp a paint container, the present invention includes first and second recesseses on the support plate, with a raised edge on the support plate forming the first recess sized to closely interfit with a generally square paint container, with an inside diameter of the first recess being substantially equal to an external diagonal dimension of the square paint container. The second recess on the support plate is preferably concentric to the first recess and has an inside diameter substantially equal to an outside diameter of a generally cylindrical paint container. As a result, the clamping frame of the paint mixer will substantially geometrically center either of the square or cylindrical paint containers when received on the support plate.

DETAILED DESCRIPTION

Referring to the Figures, and most particularly toFIGS. 1-4D, a paint mixer30useful in the practice of the present invention may be seen. As shown, mixer30is a gyroscopic type mixer that has a one gallon paint container capacity. However, it is to be understood that the present invention is also applicable to other sizes of gyro mixers (e.g., 5 gallon) and, in certain aspects, to platform mixers of various capacities. Mixer30is shown without an enclosure, however chain line32is used to indicate that preferably an enclosure is used to surround the mixer30, but forms no part of the present invention. Mixer30is supported by a base34having a horizontal member36and a vertical member38, each preferably formed of relatively rigid material, such as heavy gauge sheet metal. Members36and38may be secured together, for example, at locations39by conventional fastenings, such as machine screws or welding. A drive mechanism40is mounted to member38and includes an electric motor42and a right angle gear box44having an output shaft46. Motor42is preferably mounted to gear box44which may be mounted to member38by a pair of brackets48. Referring toFIGS. 4A and 4B, the pair of brackets48may be replaced by a single bracket49. Referring now toFIGS. 4C and 4D, in an alternative embodiment, the gear box44may be mounted to member38by a flange51surrounding an output shaft coupling45.

A stationary ring gear50is mounted to upright or vertical member38by a plurality of standoffs or spacers52. It is to be understood that the spacers52may, in the alternative, be incorporated integrally into the gear50. Shaft46projects through a machined bore54in ring gear50and is attached to a yoke arm56through a hub58. In one aspect of the present invention, a bearing60which may be a sleeve bearing or an antifriction type bearing, i.e., one having rolling elements such as balls62between an outer race64and an inner race66is received in machined bore54and supports shaft46, with the outer race received in bore54which is machined to be concentric to a pitch circle of the ring gear50, such that the shaft46is held concentric to the pitch circle of the gear50by bearing60located in bore54. Alternatively, a bore may be machined in gear50to directly support or “journal” shaft46in ring gear50concentric to the pitch circle of gear50, if desired.

Referring now also toFIG. 2A, the present invention includes an improvement to a gyroscopic paint mixer of the type having a non-rotating ring gear about which a planetating gear rotates to provide a spin motion to a paint container in a clamping frame driven by a shaft projecting through the ring gear. The improvement in combination with the mixer includes structure supporting the shaft projecting through the ring gear such that the planetating gear orbit is concentric to a pitch circle of the ring gear. The structure supporting the shaft includes a bore in the ring gear machined to be concentric to the pitch circle of the ring gear. Preferably, the structure supporting the shaft includes a bearing supporting the shaft projecting through the ring gear such that the planetating gear orbit is concentric to the pitch circle of the ring gear.

More particularly, the structure supporting the shaft may include an antifriction bearing having an outer race located concentric to a pitch circle of the ring gear and an inner race supporting the shaft projecting through the ring gear such that the planetating gear orbit is concentric to the pitch circle of the ring gear.

Referring now again toFIGS. 1,2and4, in one aspect, the present invention is directed to a clamp and lock assembly and method. A clamping frame70is supported by yoke arm56. Clamping frame70may include a lower cross member72and an inverted U shaped member74attached thereto. Alternatively, clamping frame may include an upper cross member (not shown) similar to the lower cross member72, along with a pair of upright members (not shown) corresponding to the side legs of the inverted U shaped member74. Frame70may carry a support plate76and a pressure plate78. As will be described in more detail infra, support plate is rotated by a planet gear80driving a planet gear box82through a shaft84. Pressure plate78is able to be moved towards and away from support plate76by a clamp and lock apparatus86. Plates76and78clamp a paint container, such as a cylindrical paint container88while the mixer30rotates the paint container about a spin axis90and a tumble axis92.

Referring now also toFIGS. 4-7, various details of the clamp and lock apparatus86may be seen. The apparatus86includes a lead screw94having a male helical thread96and at least one axial relief98, and preferably a plurality of axial reliefs98,100,102. The axial reliefs interrupt the helical thread96(which preferably is an ACME type thread). As used herein, “axial relief” means sufficient removal of material from the lead screw to provide a recess for receipt of a tooth (or which creates a wall surface for contact by a tooth) of a pawl to lock the lead screw against unintended rotation. The clamp and lock apparatus86may also include a collar104secured to the upper member74of the clamping frame70.

Referring now also toFIGS. 8-10, the collar104has a female mating thread106corresponding to thread96receiving the lead screw94. Alternatively, female threads may be formed integrally in the upper member74to form the collar. The apparatus86also includes a pawl108having a tooth124engaging one of the axial reliefs of the lead screw. The pawl108is arranged to be urged into engagement with the lead screw by a spring110to permit rotation of the lead screw in a first direction112which advances the lead screw94into the collar104. The pawl108selectively prevents rotation of the lead screw94in a second direction114opposite to the first direction112. The apparatus86may include the pressure plate78. Apparatus86carries pressure plate78via a bearing117and snap ring125, to advance and retract the pressure plate with respect to the support plate76, while permitting rotation of the pressure plate78with respect to the lead screw94and clamping frame70. Bearing117primarily carries a thrust load and secondarily a radial load. Pawl108has a handle116for releasing the engagement of the pawl with the lead screw to permit rotation of the lead screw94in the second direction114, retracting the lead screw94through the collar104and opening up the distance between the pressure plate78and the support plate76, for inserting or extracting a paint container from the clamping frame70. Pawl108is moved in direction118(seeFIG. 4) to pivot about pin119to release engagement of the pawl108with the lead screw94.FIG. 7shows the clamp and lock apparatus86without the collar to more clearly illustrate the engagement of the pawl with the lead screw. It is to be understood that in the embodiment shown the pawl108is pivotably mounted to the clamping frame70for selective engagement with and release from one of the axial reliefs in the lead screw. A handle121and a knob123are attached to the lead screw94to enable a convenient manual grasp to rotate the lead screw94with respect to the clamping frame70.

Referring now most particularly toFIGS. 5 through 5C, an enlarged section view of certain parts of the clamp and lock assembly86may be seen.FIG. 5Ashows the pawl108in a first, or LOCKED position152in which a first face or wall154in lead screw94abuts a first side156of the tooth124of pawl108, preventing rotation of the lead screw in the direction indicated by arrow114. In addition, a surface portion155of collar104may contact a stop portion or surface157on pawl108to prevent further rotation of the pawl108in a clockwise direction from the position shown inFIG. 5A. It is to be understood that pawl108will prevent rotation of lead screw94in the direction114with the pawl engaged as shown inFIG. 5A, both because of the “stop” feature of the contact between surfaces155and157, and also because of the interference (or lack of clearance) between tooth124and axial relief98for lead screw94to rotate in the direction114with the pawl108engaged as shown inFIG. 5A.FIG. 5Bshows pawl108in an intermediate position158in solid lines, with the LOCKED or first position152shown as a chain line. InFIG. 5B, a second side160of tooth124is in contact with a second face or wall162on lead screw94, since lead screw94has been rotated in the direction indicated by arrow112. InFIG. 5C, the clamp and lock assembly86is shown in an UNLOCKED position164, with the pawl108fully disengaged from the lead screw94. InFIG. 5C, the intermediate position158is shown as a chain line.

Referring now most particularly toFIGS. 7-11, collar104may also have a flat120with an opening122through which the tooth124of the pawl projects to engage one of the axial recesses of the lead screw. The collar104may be preferably attached to upper member74of the clamping frame70by three bolts126(shown inFIGS. 5 and 6). Alternatively, the collar may be formed integrally in member74. It is also to be understood that pin119is also attached to the upper member74, as is a spring mounting bolt128, shown inFIG. 5.

Referring now most particularly toFIGS. 7A-7D, an alternative pawl assembly108′ may be seen along with lead screw94, with parts omitted to more clearly illustrate certain aspects of the present invention. In this embodiment, pawl108′ has an over-center design where spring110′ acts along an axis113which moves from one side of pin119′ to the other side of pin119′. Furthermore, the pawl108′ may be positioned in an intermediate position in which the axis113passes through pin119′.FIG. 7Ashows the pawl108′ in a second position, corresponding to the position shown inFIG. 7D, in which the lead screw is free to rotate clockwise, as viewed inFIG. 7D. With the pawl108′, in this position, the lead screw is prevented from rotating counterclockwise. Spring110′ is extended between a fixed spring mounting bolt128′ and a spring attachment finger111located on and movable with pawl108′. As may be seen in these Figures, pawl108′ has two teeth,124aand124b, respectively engagable with each of the axial recesses or reliefs98in lead screw94. Pawl108′ also preferably has a handle116′ to operate pawl108′ between the respective positions. With the pawl108′ located as shown inFIG. 7B, lead screw94is free to be rotated in a counterclockwise direction, as viewed inFIG. 7B, and is prevented from rotation in a clockwise direction. With the pawl108′ located in the position shown inFIG. 7C, lead screw94is free to be rotated in either direction.

Referring now toFIGS. 7E-7H, a still further alternative embodiment pawl assembly108″ may be seen, along with lead screw94, with parts omitted to illustrate certain aspects of the present invention. In this embodiment, the pawl108″ operates with a linear motion. A handle116″ may be used to manually retract a tooth124″ of pawl108″ from engagement with lead screw94, as shown inFIG. 7H. When handle116″ is released, pawl108″ is urged by spring110″ towards lead screw94, such that the tooth124″ engages one of the axial recesses or reliefs98in the lead screw94, as shown inFIGS. 7E,7F, and7G.FIGS. 7E and 7Fshow a cover127having a slot129for handle116″ to project through.FIGS. 7G and 7Hshow the cover127removed, to illustrate that the spring110″ reacts between an end wall131and the sliding pawl108.″

From the above, it may be seen that in one aspect, the present invention includes a method of selectively clamping and locking a paint container in a paint mixer by advancing a lead screw (preferably by manually grasping and rotating a handle attached to the the lead screw), with the lead screw carrying a pressure plate to urge the pressure plate against a paint container, and urging a pawl into engagement with an axial relief in the lead screw (via a spring), with the pawl permitting rotation of the lead screw in a first direction to advance the lead screw and selectively preventing rotation of the lead screw in a second direction opposite to the first direction to prevent retraction of the lead screw and release of the paint container by the pressure plate. The method may also include manually disengaging the pawl from the lead screw, and retracting the lead screw to release the pressure plate from the paint container.

In a first alternative embodiment, the pawl may have an over-center design to hold it in one of at least two, and possibly three positions, with a first position (LOCKED) engaged with the lead screw preventing retraction of the lead screw from clamping a paint container and a second, intermediate position (UNLOCKED) disengaged from the lead screw, permitting rotation of the lead screw in either direction, and in a third (REVERSE LOCKED) position, preventing advancement of the lead screw into engagement and clamping of the paint container. With such an over-center design, the pawl may be alternately arranged to lock the lead screw against rotation in both directions when the pawl is in the LOCKED position, and to permit rotation in both directions when the pawl is in the UNLOCKED position.

As a still further alternative the pawl may be constrained to slide linearly (generally radially) with respect to the lead screw, rather than rotate. With such an arrangement, in one version the pawl may be selective to permit rotation in one direction and prevent rotation in the other direction, or (in another version) may prevent rotation of the lead screw in either direction when the sliding pawl is engaged with the lead screw. With this alternative, a spring is provided to urge the pawl into engagement (in either version).

Referring now also toFIGS. 12-15,17and18, various aspects of the present invention relating to the support plate76may be seen. The support plate76has a generally flat working surface130surrounded by a raised edge131(which is preferably, but not necessarily formed by a peripheral lip132), with the edge or lip forming a first recess133on the support plate sized to closely interfit with a generally square paint container135. An inside diameter134of the recess133existing within lip132is preferably substantially equal to an external diagonal dimension136of the square paint container135.

The support plate76also has a second recess138formed by a step140in working surface130. The second recess138is concentric to the first recess133and has an inside diameter142substantially equal to an outside diameter144of the generally cylindrical paint container88. By “substantially equal” as to the diameters134and142in reference to the dimensions136and144is meant that sufficient clearance is provided to insert and remove the respective containers135and88, while also substantially geometrically centering the respective container when it is received on the support plate76.

Referring now most particularly to FIGS.13and16-19, it is to be understood that the support plate76of the present invention is also sized to closely interfit with a footprint146of a generally D-shaped paint container148to hold the D-shaped container in a fixed alignment in the clamping frame on the support plate76. This is accomplished by sizing the diameter134of the first recess133to closely interfit with a maximal dimension150of the container148.

By “maximal dimension” is meant, for a non-cylindrically shaped container (which may have a non-symmetrical horizontal cross section footprint) the diameter of the smallest cylinder into which the non-cylindrically shaped container footprint will fit. For a rectangular footprint container, the maximal dimension is a diagonal between opposite corners of the rectangular container. For a D-shaped container, the maximal dimension will be a side of an isosceles triangle extending from the mid point of the D-shaped arc to one of the opposite corners, unless the radius of curvature of the D-shaped arc is greater than half the diameter of the maximal dimension cylinder.

In this aspect, the present invention includes a method of geometrically centering one of a plurality of different cross-section paint containers in a gyroscopic paint mixer of the type having a support plate. The method is performed by providing a peripheral lip on the support plate to form a first recess having a first diameter sized to closely interfit with of each of a plurality of non-cylindrical paint containers, where each of the containers has substantially the same maximal dimension, and providing a step in the support plate to form a second recess having a second diameter less than the first diameter and sized to closely interfit with a diameter of a cylindrical paint container. The method also includes placing a paint container on the support plate, where the paint container is selected from the group of: i. non-cylindrical paint containers having a maximal dimension substantially equal to the first diameter, and ii. cylindrical paint containers having a diameter substantially equal to the second diameter such that the paint container is placed within the respective recess within which it closely interfits.

This invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.