MORTAR MIXING DRUM ASSEMBLY

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The present invention relates to mortar mixing drum assemblies and particularly to improvements in the mixing apparatus and associated operational safety matters.

TECHNICAL FIELD

Conventional mortar mixing apparatus includes a bag splitter located on a pivotally mounted grate on the drum over rotating mixing paddles. In addition, the engine used to rotate the paddles is enclosed in a cab that can be opened to start/stop the engine and closed, for safety purposes, when the engine is running. What is needed is a new drum configuration for better loading and mixing and safe operation of the assembly engine at the same time.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention there is provided a portable mixing drum assembly including a frame, a mixing drum having a lower hollow substantially cylindrical body with an upper enlarged outlet opening covered by a pivotally mounted grate, the drum having a pair of spaced end walls and a laterally disposed discharge chute of approximately 24 inches wide extending from the outlet opening and a back wall spaced away from the chute and integral with and extending upwardly from the body. A shaft is mounted medially between the end walls and carries a pair of oppositely disposed arms each having a center paddle. An engine is mounted on the frame operatively connected to the shaft for rotating the shaft and starter operating controls are located closely adjacent the engine for the safe operation thereof. The back wall of the body is inclined from the vertical by no more than 15° to inhibit build up of the mortar being mixed in the drum.

An additional pair of V-shaped mixing paddles is mounted on respective arms for increasing the amount of entrained air in mixed mortar. The arms are medially located on the shaft. Each of the additional paddles includes opposite end portions which are angled toward each other and toward the shaft for

increasing air entrained in the mortar during mixing of the mortar. A bag splitter is affixed to the grate, including at least one vertically extending sharpened splitting member above the shaft for penetrating a bag carrying a mortar component to create an opening therein to release the contents thereof into the drum. Preferably, the splitter further includes a spaced pair of sharpened second splitting members on opposite sides of the first splitting member for increasing the size of the opening in a bag created by the at least one splitting member.

A cab is mounted on the frame for substantially enclosing the engine and includes a first section affixed to the frame, a second section movably attached to the first section and movable between a first position covering the engine and a second position exposing a rearward portion of the engine. The second section has a front open face and a rear face with an access opening in a lower portion thereof for ready access to the starter operating controls of the engine when the section of the cab is in the first position. The second section includes an exhaust vent to provide passages from the cab for exhaust from the engine. The discharge chute is located on one side of the assembly and the exhaust vent is located on another side. The rear face includes at least one vent above the access opening for directing engine exhaust rearwardly out of the cab. The two- part engine cab has a rear section pivotally attached to a fixed front section, the rear section including a side engine exhaust vent, the rear section of the cab also including an enlarged opening for access to the starter operating controls of the engine.

BRIEF DESCRIPTION OF THE DRAWING

The following description taken in connection with the accompanying drawings illustrate the invention:

FIG. 1 is a perspective view of the improved mixing drum assembly in accord with the present invention showing the closed engine cab;

FIG. 2 is a left side elevation view of the assembly of FIG. 1;

FIG. 3 is a perspective view of the assembly of FIG. 1 showing the engine cab in the open position;

FIG. 4 is a cutaway end view of the drum of FIG. 1 ;

FIG. 5 is a side elevation view of the improved mixing drum of FIG. 1 ;

FIG. 6 is an end view of the mixing drum of FIG. 5;

FIG. 7 is a top plan view of the mixing drum and center paddle assembly; and

FIG. 8 is a perspective view of the paddle assembly.

DETAILED DESCRIPTION OF THE INVENTION INTRODUCTION

In some mixing drum designs the back lip of the drum is angled in a manner that provides a "shelf effect" that allows for accumulation of mortar along the back lip of the drum. The present mixing drum has a back lip that varies from the vertical by no more than 15°. This structure eliminates the "shelf effect" found in prior art drums.

Many drums incorporate a bag splitter mounted on the covering grate to allow for ease of loading the drum with mortar, sand, or an appropriate mix as desired. The present drum assembly incorporates three upwardly directed splitter peaks. The middle peak is taller than the other two to provide a target for a user in placing the bag on the center of one side of the bag by a user, and is located directly over the mixing paddle shaft. In addition, the bag splitter is positioned over the widest area of the drum opening or throat to split the bag in the optimum position.

The width of the pouring or discharge chute has also been increased to provide for more effective use of the newly designed back lip and splitter.

Generally, belt-driven mortar mixers use two-piece engine cabs that should be closed when the engine is running to protect the users from engine parts and gears. In reality, however, cabs are left open while the engine is running because access to the "rope pull start" apparatus and the start/stop switch have to be operated many times during a normal day.

The present assembly provides a two-piece cab that totally encloses the engine but for access to the rear of the engine and the operating controls of the engine when in normal use. In addition, the vent ports have been modified.

Finally, additional shaped paddles are mounted to the center paddle arms to improve the mixing of mortar therein.

CONSTRUCTION

With respect now to the drawings, FIGS. 1 and 2 illustrate the mixing drum assembly generally at numeral 10. The mixing drum is shown generally at 11 and is attached to a conventional engine 12 as understood in the art.

With respect also to FIGS. 3-4, engine cab 13 has two sections, rear section 14 that is pivotally mounted via hinge 15 at front face 2OA to a fixed front section 16 including drive gear shield 16A mounted to front section 16 medially of cab 13 to provide the highest level of worker safety and to provide protection from dust and debris which extends the life of the drive components, from the engine to the paddle shaft. Rearward opening 18 provides access to the engine 22 which includes a "pull-to-start" apparatus 23 and other engine controls. Side vent port 20 provides an exit passage for air from muffler 22A of the engine 22. Air is also exhausted through vent ports 19 located in the rear face section 24 of cab section 20. A solid panel 25 may be used in place of opening 21. Furthermore, vent 20 faces the back side 26 of assembly 10 so as not to have engine exhaust blowing towards a user standing on the opposite front side 27.

The mixing drum 11 is illustrated in more detail in FIGS. 5-7. Drum body 28 includes flat end walls 29, 30, a substantially cylindrical section 31 and an outlet discharge opening 32.

Paddle shaft 33 is mounted via conventional bearings 34, 35. Handle 36 is used to rotate the drum body 11. Engine 22, gearing 37 and other transmission and clutch apparatus is conventional as understood in the art.

Outlet opening 32 is formed by vertical end walls 38, 39 that are integral with respective end walls 29, 30. Back wall or lip portion 40 includes flanges 41 and 42 which are used for pivotally mounted cover grate 43 on pins 44, 45 (FIG. 5).

Grate 43 includes six bars 46 to which is mounted bag splitter 47 which includes two sharpened short peak members 48 and a sharpened taller peak member 49. Bag splitter 47 is mounted by bolting or welding on the third bar from the front of assembly 10 to position the splitter 47 over the widest portion of opening 32 to provide a target for a user.

N Back wall 40 is inclined or angled to slant no more than 15°, preferably 5°- 15°, from vertical axis 53 to eliminate the "shelf effect" that exists in drums with a back lip angled to a greater degree. Preferably, wall 40 is angled away from

opening 32 at about 5°. The width of opening 32 has been increased to create a discharge chute 50 of approximately 24 inches from 15 inches in some earlier drums bodies.

With regard to FIGS. 7, 8, additional shaped paddles 51 have been added to central paddles 52 that are mounted on arms 33A affixed to shaft 33. Paddles 51 provide improved mixing of the mortar in drum 11. The paddles 51 are V- shaped by a slant or angling opposite end portions inwardly toward the shaft 33 and each other to create a Venturi effect which operates to force air into the mix as the central paddles are rotated. The increased quantity of entrained air makes the mix creamier and actually lowers the temperature of the mixed mortar by 5 ⁰ F or more. This result provides better spreadability and proven longer board life which provides more time before coarse tooling is required. Paddles 51 are displaced endwise with respect to each other wherein each such additional paddle includes opposite end portions, each end of the end portions being angled toward each other with respect to the shaft to avoid pushing exactly the same mortar and thus improve mixing.

Standard loop latches 54, 55 and associated posts 56, 57; 58,59; connect cab sections 14 and 16 together and connect section 16 to frame 17 and are used to secure front section 16 in the down closed position as understood in the art (FIGS. 1 , 2).