Background of the Invention.

This application is a continuation-in-part application of my co-pending patent application U.S.S.N. 08/412,080 filed March 28, 1995 which is a continuation-in-part application of co-pending application U.S.S.N. 08/147,978, filed November 5, 1993, now issued as U.S. Pat. No. 5,401,098 on March 28,

1995.

The field of the invention pertains to light-weight portable mixers and, in particular, to hand-held powered mixers for thick heavy viscous liquids which may contain solids.

Typically, concrete, cement mortar, gypsum and other similar construction materials are mixed in stationary, truck or trailer mounted rotary bowls. The bowls are equipped with curved fins inside to assist in thoroughly mixing water with the powder and aggregates. Even the smallest bowl mixers are too heavy for one person to easily lift because of the weight of the steel bowl and attached motor. When a relatively small amount is needed these construction materials are typically hand mixed with a perforated hoe in a metal trough.

Despite the need for a truly portable powered hand-held mixer, apparently none are commercially available. An early apparently portable mixer is disclosed in U.S. Pat. No. 994,978. This mixer has an externally driven shaft with a plurality of curved mixing blades thereon. The material is mixed as the blades move the material parallel to the shaft to the outlet.

U.S. Pat. No. 3,166,303 discloses a plurality of blades on a vertical shaft as the mixing device. The shaft is powered by a portable electric drill and a vertical barrel is used to contain the mix. U.S. Pat. No. 3,185,451 also discloses an electric powered hand-held mixer having a pair of counter-rotating spiral wire blades. The mixer is used in a large mixing trough.

U.S. Pat. No. 4,761,076 and an advertising brochure from Sears,

Roebuck & Co., Chicago, Illinois disclose a wheeled mixing tub equipped with an auger mixer. The auger is gasoline powered and mounted permanently to the tub in a manner that permits the auger to be moved from one side of the tub to

the other. Thus, the mixer is not truly portable in the manner of a hand-held mixing device.

Summary of the Invention- It is an object of the invention to provide a sufficiently powerful hand-held mixer than can quickly and efficiently mix concrete, mortar and gypsum in small quantities.

It is a further object of the invention to provide a mixer that is as light, portable and simple to operate as other common power tools and power yard implements intended for the home handy-man or woman. It is also an object of the invention to provide a powerful hand held-mixer to mix concrete, the mixer being easy to position and control by the user whether the user is behind or to a side of the mixer.

It is a further object of the invention to provide sufficient transverse flow of the material being mixed to achieve quick and effective mixing thereof. It is a further object of the invention to provide a control device on the mixer to effect a speed change of the travel of the mixer through the material desired to be mixed.

The new mixer is based upon a small hand-held gasoline powered garden tiller such as the Ryobi Cultivator Model 41 Or from Ryobi Outdoor Products, Inc. , Chandler, Arizona. The blade assembly is modified by adding circular steel rings having a diameter slightly greater than the maximum diameter swept by the tiller blades. The steel rings are formed of rod and brazed or welded to the tips of the tiller blades. Additional steel rod spokes attach the rings to the blade hubs. The rings permit the hand-held tiller to be operated in a mixing trough without damage to the trough or the blades of the tiller.

In order to provide greater control of transverse flow of the material to be mixed, a shroud device partially surrounds the mixing blades to direct the flow of material. The shroud device may have openings or be made from wire rod to allow flow yet protect the mixing blades. The shroud device may have a slightly greater periphery than the largest mixing blade to alleviate the engagement of the mixing blades with the bottom of the mixing trough. Portions of the shroud

device may be free to rotate with the mixing blades or independent of the mixing blades.

The mixer is particularly effective and convenient. The prototype mixer weighs about twenty-five pounds and mixes thoroughly a one-hundred pound bag of ready-mix concrete or mortar with water in less than three minutes. Although described in terms of steel blades and rings, the mixing blade assemblies can be constructed of other metals or engineered plastics. With engineered plastics, inadvertent impacts are less likely to dent the blade assemblies or damage a container.

Description of the Drawings.

FIG. 1 is a perspective view of the new mixer;

FIG. 2 is a close-up perspective view of one of the blade assemblies for the mixer;

FIG. 3 is a perspective of a small separate mixing trough that is particularly effective with the mixer;

FIG. 4 is a perspective view of the top of the mixer having a movable handle;

FIG. 5 is an exploded perspective view of the movable handle illustrating the assembly thereof; FIG. 6 illustrates a partial view of the bottom of the mixer from the side showing a flexible extension affixed to the drag bar;

FIG. 7 illustrates a partial perspective view of the mixer having a shroud with depending fixed sides;

FIG. 8A is a front view of a depending side of FIG. 7; FIG. 8B is a front view of a modification of a depending side having openings therein;

FIG. 8C is a front view of a depending side formed from wire rod;

FIG. 9A illustrates a partial perspective view of the mixer having a shroud with depending fixed sides and side wheels attached thereto; FIG. 9B is a partial view of the attachment of a side wheel to a depending fixed side;

FIG. 10A is a front view of the side wheel of FIG. 9A;

FIG. 10B is a front view of a side wheel modified to contain openings therein;

FIG. IOC is a front view of a side wheel constructed from wire rod;

FIG. 11A illustrates a partial perspective view of the mixer having a side wheel attached to the transverse shaft;

FIG. 1 IB is a partial view of a driving connector between the side wheel and the transverse shaft;

FIG. 12 is a partial perspective view of the mixer with one side wheel removed showing a free wheeling connector for the side wheel; and FIG. 13 is a perspective view of the mixer with a water tank attached thereto.

Description of the Preferred Embodiment.

Illustrated in FIG. 1 is a small hand-held tiller generally denoted by 10 that is modified into a mixer. The tiller 10 includes a small gasoline engine 12 mounted on a drive shaft housing 14 that in turn is covered with a hand grip 16. Attached to the drive shaft housing 14 is a pair of handles 18 also with hand grips 20. At the lower end of the drive shaft housing 14 is a gear box 22. Located within the drive shaft housing 14 is a drive shaft connected to the engine 12 and extending into the gear box 22. Extending horizontally from the gear box 22 is a shaft 24 upon which are mounted two pairs of blade assemblies 26 and 28 to either side of the gear box 22.

Referring to FIG. 2 each blade assembly 26 or 28 comprises a disc and hub 30 for mounting on the shaft 24 and four tines 32 and 32 ¹ that are bent over from the disc in the same manner as tiller tines. A steel ring 34 is welded or brazed to the tips of the two diametrically opposite tines 32 that extend in the same direction. The two alternating diametrically opposite tines 32 ¹ extend in the opposite direction and are connected to the ring 34 by short transverse pieces 36 of rod welded therebetween. In addition, a plurality of short radial rods 38 extend from the disc and hub 30 area to the ring 34 to form spokes welded or brazed therebetween. The entire blade assembly forms a rigid "cage" that both protects the tines 32 from impact with the container of the material to be mixed and assists in mixing the material. As shown the ring 34 limits the mixing blade

assembly radially and outwardly transversely, however, small purposeful transverse or radical wiggles in the ring or smooth bumps extending laterally or radially may assist in the mixing without causing vibration of the mixer or gouging of the container and are therefore considered to be within the concept of the circular ring being the outside limit of the extent of the blade assembly.

Although the new mixer may be used with any large conventional concrete and mortar hand mixing trough or container of sufficient size, a particularly convenient mixing trough 40 is shown in FIG. 3. The trough is sized to a width about one inch greater than the full blade width of the new mixer. The trough is also about three feet long and one foot deep. The bottom 42 of the trough 40 is curved upward at the ends 44 to eliminate bottom corners that otherwise would collect unmixed or ineffectively mixed material. The trough 40 also includes a set of wheels 46 at one end and a handle 48 at the other end. A single eighty or one-hundred pound bag of ready-mix concrete or mortar can be quickly mixed with water using the mixer. The trough 40 can then be easily wheeled to the desired location and dumped by raising the handle.

Cleaning of the mixer and trough are also greatly simplified in comparison with conventional concrete and mortar mixers. The trough is merely filled with fresh water and the mixer operated in the water in the trough. The vigorous mixing action quickly and effectively cleans both mixer and trough.

As alternative forms of the mixer an electric motor may be substituted for the small gasoline engine. The blades may also be modified in shape to have external peripheries substantially circular in circumference. The substantially circular peripheries protect the blades and container from impact damage in substitution for the rings.

Illustrated in FIG. 4 is an improvement to one of the pair of handles 18 with hand grips 20. One of the handles 18 has means for moving and positioning the handle 18 relative to the other handle 18' and grip 20', the means for moving and positioning denoted as 50. FIG. 5 clearly shows the means for moving and positioning generally denoted as 50 as an adjustment device 52. The handle 18 is severed at 68 and the adjustment device 52 is then located onto the handle 18. The adjustment device 52 comprises a slip fit tube 54 to join the severed ends of the handle 18, an upper

6 coupling 56, a lower coupling 58, and means 60 such as a screw for attaching the upper coupling 56 and tube 54 to the handle 18. The lower coupling 58 is attached to the handle 18 with a second screw 62. Screw 62 only engages the handle 18. Means for biasing 64 the lower coupling 58 to the upper coupling 56 such as a spring, engage the lower edge 70 of the coupling 58. A housing 66 (shown in phantom) covers the adjustment device 52 and is also retained by screw 60 to handle 18. Screw 62 is hidden beneath the housing 66.

The means for biasing 64 the lower coupling is here shown as a spring but other biasing means such as resilient bands could be advantageously employed. The couplings have castellated joining surfaces 72 that interengage, thereby retaining the upper and lower coupling 56, 58 in a joined configuration until they are selectively disjoined as shown. The spring 64 is trapped between the lower edge 70 of the coupling 58 and a bottom edge 73 of housing 66 which extends slightly inward into close proximity with handle 18. It is to be understood that although shown on one handle 18, one or more handles could advantageously employ the means for moving and positioning 50. Referring back to FIG. 4 it may be noted that the handle adjustment means 50 requires that the housing 56 and a portion of the mixer below the adjustment means must be simultaneously gripped to extend and rotatably reposition the grip 20 and handle 18. Thus, the user must release the throttle lever 51 to reposition the grip 20. Preferably, the user grasps the hand grip 16 and the housing 66 to extend and reposition. If the user attempts to reposition by grasping the grip 20, the offset from the axis of the adjustment 50 causes slip fit tube 54 to bind within handle 18. Thus, by employing the above, at least one of the handles 18 can be rotated by 90 degrees or another angle depending on the number of castellations employed. This rotation allows the user to stand beside the mixer 10 and exert greater control over it by grasping grip 20 and hand grip 16 in the manner of a shovel. This control feature is particularly useful while the mixer 10 is moving through material in a trough because the user does not need to stretch from one end to reach the other end of a long trough while operating the mixer. Nor does the user now need to strain awkwardly across the mixer 10 to hold the handles in

a non-ergonomic grasp. The mixer is as easy to move as a grain or snow shovel and therefore can easily be used to mix in a wheelbarrow.

Now turning to FIG. 6, a mixing drag bar generally denoted as 74 is shown at the back of the mixer 10. A normal drag bar on a rototiller is made from narrow flat metal bar stock that must be manually adjusted and extends beyond the sweep of the rotating tines. In contrast, the mixing bar 74 of the invention comprises a tube 76 extending from a shroud 78 emplaced across the top 80 of the gear box 22 of the mixer 10. The tube 76 attaches to the center of the shroud 78 and curves behind the gear box 22. The tube 76 curves with substantially the same radius as the blade assemblies 26, 28. The drag bar 76 is tubular to prevent material from clogging between the gear box 22 and drag bar. The tube 76 is stabilized by attaching it by a bracket 82 to a corner of the bottom 84 of the gear box 22.

An extension tip 86 about two inches long and one inch wide is attached to and extends from the tube 76. The extension tip 86 may be curved to follow the substantially circular periphery as with the mixing drag bar 74 or extend somewhat tangentially from the circular periphery. The extension tip 86 extends approximately directly beneath the gear box 22 and can be formed from plastic material as it is desirable that the extension tip 86 be flexible. The flexibility allows the extension tip 86 to conform to the bottom of the trough in which the mixer is used. The extension tip 86 thus self adjusts and scrapes cleanly but does not gouge the bottom of the trough. The extension tip 86 also spreads the material from under the gear box 22 and holds the mixer down in the material to avoid leaving any material in the bottom of the trough as it is being mixed. In contrast, if a solid stiff extension was substituted, the extension would tend to gouge the bottom of the trough instead of conforming to it. This contact eventually would gouge out parts of the trough particularly if the trough were formed from wood or plastic.

The forward motion of the mixer 10 is controlled by the tilt that the user of the mixer provides to the handles. The user can cause the mixer to move faster through the material by moving the handles in a downwardly and backwardly orientation because the flexible extension tip 86 becomes horizontal against the bottom of the trough creating less resistance to forward motion. The

material forced over the flexible plastic extension tip 86 pushes the tip down keeping it firmly on the bottom of the trough and controls the forward pull of the mixer, keeping the mixer from running up and out of the material.

An opposite effect is achieved when the user moves the handles in an upwardly and forwardly orientation; namely, the forward motion of the mixer is slower through the material to be mixed. As the extension tip 86 moves out of a horizontal position on the bottom of the trough it impedes the flow of the material thereby slowing the forward motion of the mixer 10. The weight of the mixer 10 itself and a vertical orientation of the mixer causes the mixer to move downwardly when it is introduced into the material to be mixed in the trough. Therefore, the user's positioning of the handles effectively controls the speed of travel of the mixer through the material. The flexible extension tip 86 is envisioned to be fabricated from different widths and flexibilities of flexible material to suit various mixing needs. The control of the motion of the mixer 10 is facilitated by the open wheels

86 of the blade assemblies 26, 28. The open wheels 88 allow the material being mixed to flow easily transversely through the blade assemblies 26, 28 whatever the tilt that the user has imparted to the mixer 10 through the handles 18. The transverse flow of the material helps to quickly and effectively mix the material. As the mixer is used, the user can push the handles downwardly or upwardly thereby angularly moving the extension tip 86 in the material to be mixed. This has the effect of either speeding or slowing the progress of the mixer through the material because the extension tip is moved in its position in the material. By downwardly and backwardly deflecting the handles, the extension tip 86 angles for a better flow of the material. Conversely, if the handles are pulled upwardly and forwardly, the extension tip 86 moves thereby slowing the material flow. The extension tip 86 is shown in a basically horizontal position in FIG. 6.

FIGs. 7-12 illustrate further optional improvements to the portable hand- held concrete and mortar mixer that is the subject of this continuation-in-part application.

Now turning to FIG. 7 an improvement to the hand-held mixer 10 is illustrated. Extending from the ends 88, 90 of the shroud 78 that is emplaced

across the top 80 of the gear box 22 of the mixer 10 are depending sides 92, 94. The depending sides 92, 94 are affixed to the ends 88, 90 of the shroud 78 respectively by attaching means such as an interengaging nut 98 and bolt 100. Other attaching means such as welding or snap fitting could be effectively utilized. The lower parts of the depending sides 92, 94 extend slightly beyond the largest periphery of the mixing blade assemblies 26, 28 and serve to retain and route the material to be mixed adjacent the mixing blade assemblies 26, 28. Further, the depending sides 92, 94 prevent the mixing blade assemblies from undesirably engaging the sides and the bottom of the mixing trough 40 when the mixer 10 is moved through the material. With the protective sides 92, 94 or wheels below, the mixing blade assemblies need not have the circular outer peripheries as shown in FIGs. 1 and 2.

Various configurations of the depending sides 92, 94 are illustrated in FIGs. 8A, 8B and 8C. A solid depending side 92' (FIG. 8A), a depending side 92" having openings (FIG. 8B) and a depending side 92" formed from wire rod having inherent openings (FIG. 8C) are all advantageously employable as sides 92, 94. The transverse flow of the material can be more readily controlled, yet the blade assemblies are protected from engagement with the mixing trough.

Another variation of the device comprises wheels 104, 106 attached to the depending sides 92, 94 (FIG. 9A). The wheels 104, 106 are rotatably attached to the depending sides 92, 94 to enable the mixer 10 to ride on the wheels 104, 106 on the bottom of the mixing trough. The wheels 104, 106 are attachable and detachable from the depending sides 92, 94 by connecting means 108 such as a nut 110, a bolt 112, a washer 114 and a lock washer 116 (FIG. 9B). Similarly as described above with reference to the configuration of the depending sides 92, 94, the wheels 104, 106 can be configured either as a solid piece 104' (FIG. 10A), with openings 104" (FIG. 10B), or from wire rod 104"' forming a spoked wheel (FIG. 10C). Other configurations could also be used.

A variation of the mixer 10 as depicted in FIGs. 11A, 11B and 12 attaches the wheel 104 to the transverse shaft 24 of the mixer 10. As shown (FIG. 11B) the wheel can be fitted with a drive connector for the direct driving of the wheel by the shaft 24. A "D" drive connector 118 is formed in the wheel 104 to engage

congruently with a flat 120 on the shaft 24. Hence, the wheel 104 is rotated with the rotation of the shaft 24 and the mixing blade assemblies attached to the shaft.

In substitution for the direct drive connection, FIG. 12 shows free wheeling attachment means for the wheel (with the wheel 104 removed). This attachment means (similar to the attachment shown in FIG. 9B) allows the wheel 104 to be ree wheeling by the absence of a driving engagement.

The wheels depicted in FIGs. 11 A, 11B and 12 can have openings, perforations or be spoked wheels formed from wire rod as described above.

Employing any of the above variations effectively prevents engagement of the mixing assemblies with the trough surfaces while enabling flow of material to the blades themselves.

FIG. 13 depicts a water tank 120 specifically shaped to fit on the mixer 10. The tank 120 is removably attached to the handles by any conventional means (not shown). The tank 120 is shaped of hollow tubing in the form shown to partially surround the engine 12 without interfering with its operation. At the bottom of the tank 120 and just ahead of the shroud 78 is a drain plug 122 operable by a lever on one handle through a cable in a conventional manner. With the water tank 120 accessory, water can be periodically added to the material being mixed until the desired stiffness of the mix is achieved. The tank 120 may be refilled through a filler cap and opening at the top or a water hose attached to the filler opening in a conventional manner.