Electric Concrete Transportation Cart

Abstract

An electrically powered, self-propelled cart for safely delivering heavy loads, such as concrete, within job sites with unlevel, irregular, or sloped terrain. A cargo bucket is tiltable over front drive wheels for transporting and dumping cargo. Electric drive motors associated with a transaxle propel wheels at a selectable speed in response to an electric control module. A steering column rotates in response to manually operated handle bars and activates a sensor to generate signals delivered to the control module for throttle adjustments. The sensor may be a linear potentiometer, a rotary differential transformer or a rotary encoder or shaft encoder measuring angular displacement. Extreme steering displacements will electrically reduce cart speed notwithstanding the previous speed setting chosen by the operator through the steering column.

Claims

1. A self-propelled, steerable electric cart comprising: wheels supporting the cart, the wheels comprising at least one steered wheel and at least one driven wheel; a cargo bucket for hauling and discharging loads; at least one electric motor for driving said at least one driven wheel; a steering system adapted to be turned by a cart operator for steering said cart, wherein the steering system is mechanically linked to said at least one steered wheel; a manual throttle; a throttle control module mechanically connected to the throttle; and, a steering displacement sensor mechanically linked to at least a portion of said steering system for deriving electrical control signals proportional to steering displacement, said control signals delivered to said throttle control module for limiting excessive speed.

2. The cart as defined in claim 1 wherein the manual throttle comprises a hand grip linked to said throttle control module for selecting cart speed.

3. The cart as defined in claim 1 wherein the steering system comprises a collar that mounts said sensor.

4. The cart as defined in claim 1 wherein the steering displacement sensor comprises a linear potentiometer.

5. The cart as defined in claim 4 wherein the manual throttle comprises a hand grip linked to said throttle control module for selecting cart speed, and wherein the steering system comprises a collar that mounts said linear potentiometer.

6. The cart as defined in claim 1 wherein the steering displacement sensor comprises a differential transformer.

7. The cart as defined in claim 6 wherein the manual throttle comprises a hand grip linked to said throttle control module for selecting cart speed, and wherein the steering system comprises a steering column portion mounting said differential potentiometer.

8. The cart as defined in claim 1 wherein the steering displacement sensor comprises a rotary encoder for measuring angular displacement.

9. The cart as defined in claim 8 wherein the manual throttle comprises a hand grip linked to said throttle control module for selecting cart speed, and wherein the steering system comprises a steering column portion mounting said rotary encoder.

10. A self-propelled, steerable electric cart comprising: wheels supporting the cart, the wheels comprising at least one steered rear wheel and at least one driven front wheel; a cargo bucket for hauling and discharging loads; a transaxle for driving said at least one driven wheel; a steering system adapted to be turned by a cart operator for steering said cart, wherein the steering system comprises a steering column shaft mechanically linked to said at least one steered rear wheel; a manual throttle; a throttle control module mechanically connected to the throttle; and, a steering displacement sensor associated with said steering system for deriving electrical control signals proportional to steering displacement, said control signals delivered to said throttle control module for limiting excessive speed.

11. The cart as defined in claim 10 wherein the steering displacement sensor comprises a linear potentiometer.

12. The cart as defined in claim 10 wherein the steering displacement sensor comprises a differential transformer.

13. The cart as defined in claim 10 wherein the steering displacement sensor comprises a rotary encoder for measuring angular displacement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the accompanying drawings, which form a part of the specification and which are to be construed in conjunction therewith, and wherein like reference numerals have been employed where reasonably possible to indicate like parts in the various views:

[0032] FIG. 1 is a frontal isometric view of my new Electric Concrete Transportation Cart constructed in accordance with the best mode of the invention, showing it deployed in a construction zone over rough terrain and upon an irregular, sloped pathway that is partially obstructed by debris;

[0033] FIG. 2 is a left, frontal isometric view thereof;

[0034] FIG. 3 is a right, rear isometric view thereof;

[0035] FIG. 4 is a left, rear isometric view thereof;

[0036] FIG. 4A is a fragmentary isometric view based on FIG. 4, with parts thereof broken away or shown in section for clarity;

[0037] FIG. 5 is a right side elevational view thereof;

[0038] FIG. 6 is a left side elevational view thereof;

[0039] FIG. 6A is a half section isometric view derived from FIG. 6;

[0040] FIG. 7 is a front plan view thereof;

[0041] FIG. 8 is a rear plan view thereof;

[0042] FIG. 9 is an enlarged, fragmentary isometric view of a preferred sensing apparatus, derived generally from line 9-9 in FIG. 1, with portions thereof broken away or shown in section for clarity, or omitted for brevity;

[0043] FIG. 10 is an enlarged, fragmentary sectional view taken generally along line 10-10 of FIG. 9;

[0044] FIG. 11 is a view similar to FIG. 10, but showing steering parts in a displaced position;

[0045] FIG. 12 is a fragmentary isometric view of the cart showing the cargo box in a tilted position;

[0046] FIG. 13 is a simplified diagrammatic block diagram of the speed control arrangement and control module;

[0047] FIG. 14 is a simplified block diagram of the analog speed control arrangement; and,

[0048] FIG. 15 is a simplified block diagram of a digital speed control arrangement using a displaceable linear sensor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] With initial reference now directed to FIGS. 1-6 of the appended drawings, an electrically powered, self-propelled, cart or buggy constructed in accordance with the best mode of the invention has been generally designated by the reference numeral 10. (For purposes of the disclosure the terms “cart” and/or “buggy” are used interchangeably.) The cart 10 includes many chassis and frame similarities to prior U.S. Pat. No. 10,384,704 entitled “Steering Responsive Speed-controlled Buggy” issued Aug. 20, 2019 which, for purposes of disclosure, is incorporated by reference as if fully set forth herein.

[0050] Cart 10 is adapted to be deployed within a construction zone or work site for moving materials or supplies or tools to work site positions over an available pathway over ground 16. The cart 10 is especially adapted for hauling small batches (i.e., up to 2500 pounds) of green concrete to areas that cannot be safely or conveniently reached by much larger and heavier concrete mixing trucks. As appreciated from FIG. 1, ground 16 is unlevel, and travel pathways in the direction of point 25 over ground 16 may be sloped and rough. There is debris 18 scattered about. Therefore the cart 10 must be stable when heavily loaded, and it must safely accommodate irregular and unlevel pathways while moving heavy loads. To this effect it has been determined that unfortunate accidents involving tipping or rolling over are often caused, at least in part, by excessive speed. Further, speed is a particularly destabilizing factor when steering at extreme angles, particularly over rough or sloped terrain.

[0051] Cart 10 comprises a rigid chassis 20 supporting an enclosure 22 in which parts described below are housed. Chassis 20 supports a cargo bucket 21 that is tiltable over the front drive wheel pairs 24 and 25 for conveniently dumping cargo transported within bucket interior 23. Drive wheel pairs 24 (FIG. 3), 25 (FIG. 2) are driven by a transaxle assembly described below. A hydraulic cylinder 26 (i.e., FIG. 12) controls the bucket 21. Normally bucket 21 is disposed in a horizontal rest position seen in FIGS. 1-3, for example, for transport or loading, but the bucket can be hydraulically tilted for material discharge as seen in FIG. 12. Power is supplied by a Vanguard five-kilowatt battery pack 33 (FIG. 4A).

[0052] In operation a human driver or workman (not shown) stands on platform 27 so that the steering inputs are manually effectuated with conveniently accessible handle bars 28. Steering may alternatively be effectuated with operating levers, a steering wheel, or other manually controlled mechanical inputs known in the art. There are a plurality of control switches etc. disposed on the top 29 of the enclosure 22. The steering handle bars 28 mount a hand-operated throttle control 30 that may be manually squeezed to increase vehicle speed. It communicates with a Kraft-brand model 2610-1010 electric throttle control sensor 31 within the cabinetry (FIG. 6A). The handlebars 28 rotate a rigid, elongated steering column 32. Steering is accomplished with steered rear wheels 34. Steering column 32 has a portion that extends downwardly interiorly of enclosure 22 and is linked to the steered rear wheels 34. The steering handlebars 28 rotate the steering column 32, which goes beneath and through cabinetry top 29 (FIG. 9) and a bearing 52, coaxially terminating in a lower steering column shaft extension 54.

[0053] Alternative means are provided for detecting angular steering displacements in response to the handlebars 28. Signals are derived from steering displacements control the speed of the cart to prevent overspeed. The lower steering column shaft extension 54 rotates in response to mechanical steering inputs (FIGS. 9-11).

[0054] In one form of the invention, the steering column portion that extends downwardly interiorly of enclosure 22 comprises an elongated, projecting extension 54 (i.e., FIGS. 1, 4) on which a rigid, encircling, control collar 58 is mounted. Collar 58 supports a pivot connection 60 on its outer circumference that ultimately controls a linear actuator sensor 66, preferably comprising a Kraft Fluid Systems SLS1322-3-050 sensor. A displaceable plunger 64 emanating from pivot connection 60 coaxially extends from the linear actuator sensor 66. The elongated body portion 67 of the linear actuator sensor 66 is securely, pivotally locked to a rigid, static cylinder 70 that is anchored at its top to cabinetry top 29. When steering inputs are made, resultant rotation of the collar 58 radially moves the pivot point 60 in a circular motion. In response to steering turning displacements, the linear actuator 66 varies in length as plunger 64 is forced into or withdrawn from the body actuator 67.

[0055] For example, in FIG. 11 it is seen that when collar 58 rotates in the direction of arrow 75, sensor plunger 64 is extended outwardly from body 67, thus generating a proportional, responsive electronic signal handled by the circuitry of FIG. 13. The latter signal corresponds to steering displacements. A potentiometer within sensor 66 varies in resistance depending upon the position of plunger 64 and steering deflection.

[0056] The control circuitry in block, diagrammatic form (FIG. 13) has been generally identified by the reference numeral 80. Power is supplied by a rechargeable, nominally forty-eight volt power pack designed schematically by the reference numeral 81. Steering inputs from handlebars 28 are mechanically sensed in step 82 and detected with the linear actuator sensor 66 (i.e., FIG. 9) that comprises an internal potentiometer. The elongated or retracted sensor 66 develops an electrical steering signal in sensing step 82. Displacements to the mechanical throttle control 30 described above are sensed by throttle sensing block 84, that outputs to control module 88. As represented by line 89, steering information from step 82 is also received by the module 88. Suitable comparator software steps executed by module 88 with this data influences motor speed through motor control block 90 and transaxle block 92. The transaxle 100 and a responsive, preferably A/C electric motor 101 are seen in FIG. 12. The transaxle preferably comprises a Schafer Driveline, that includes Schabmueller-brand A/C induction drive motors. It is controlled by the transaxle package 92 supplied with the motor package.

[0057] In FIG. 14 an alternative speed sensing arrangement 110 employing a rotary variable differential transformer 112 turned by the steering shaft 54A. The rotary variable differential transformer 112 measures angular displacement. It acts as an electromechanical transducer that outputs an alternating current voltage proportional to the angular displacement of its rotor in step 82A. The variable A/C output from transformer 112 on line 89A is rectified within alternative control module 88A, and delivers signals to motor control 90A that controls transaxle 92A, notwithstanding the setting of throttle control 84A.

[0058] FIG. 15 discloses a second alternative speed sensing arrangement 120. This arrangement uses a rotary encoder, i.e., a shaft encoder, to electro-mechanically derive digital signals from the steering shaft 54B. The preferred rotary encoder is an absolute encoder for indicating true steering shaft position, resulting in accurate angle sensing. Step 82B delivers digital signals via line 89B to control module 88B and motor control 90B that controls transaxle 92B, independently of the setting of throttle control 84A.

[0059] From the foregoing, it will be seen that this invention is one well adapted to obtain all the ends and objects herein set forth, together with other advantages which are inherent to the structure.

[0060] It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations.

[0061] As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.