US2003719A - Automatic reversing mechanism - Google Patents

Description

June 4, 1935. H. E. M CRERY AUTOMATIC REVERSING MECHANISM Filed March 23, 1931 INVENTOR 5 Shee ts=-Sheet l Filed March 25, 1931 5 Sheets-Sheet 2 INVENTOR June 4, 1935. McCRERY 2,003,719

AUTOMATIC REVERSING MECHANISM Filed March 23, 1931 5 Sheets-Shqet 5 INVENTOR MAM- M June 4, 1935. H. E. M cRERY 21,03,719

AUTOMATIC REVERSING MECHANISM Filed March 23, 1931 5 Sheets-Sheet 4 JZH June 4, 1935. H. E. M CRERY AUTOMATIC REVERSING IECHANISI Filed March 25, 19:51-

5 Sheets-Sheet 5 INVENTOR Patented June 4, 1935 UNITED STATES 2 ,003,719 AUTOMATIC amasmc MECHANISM Harold E. McCrery, Pittsburgh, Pa., assignor to Blaw-Knox Company, Blawnox, Pa., a corporation of New Jersey Application March 23, 1931, Serial No. 524,503

2 Claims.

This invention relates generally to a method of and apparatus for mixing concrete or like material, and more particularly to a method of and apparatus for reversing the direction of ro- 6 tation of the mixing apparatus during the interval between charging and discharging so as to obtain more thorough mixing of the contents of the mixer drum.

In the accompanying drawings which illustrate the present preferred embodiment of my invention- Figure 1 is a side elevation of a truck mixer;

Figure 2 is a plan view with the rotatable drum removed, and showing the supporting yokes for the drum, and the drum driving means;

Figure 3 is a horizontal section through one of the drum supporting yokes, the view being taken on the line IlI-III of Figure 2;

Figure 4 is a plan view of the reducing and reversing mechanism by means of which the rotation of the mixing apparatus may be reversed either automatically or manually;

Figure 5 is an enlarged plan view of the reducing mechanism shown in Figure 4, parts being shown in section;

Figure 6 is a vertical section taken on the line VI-VI of Figure 4, and illustrating the reversing mechanism; and

Figure 7 is a longitudinal section through the driving shaft and clutches forming a part of the reversing mechanism.

Referring more particularly to Figures 1, 2 and 3, the mixer comprises a rotatable drum 2 which is octagonal in cross-section and is provided with circular rings or tracks 3 through which the drum is rotated. The drum is provided with a charging opening 4 through which the material to be mixed is introduced, and with a discharging opening which may be closed by a cover 5, the operating and locking mechanism for the cover 5 being indicated generally by the reference numeral 6.

The interior of the drum is provided with vanes 1 disposed at an angle to the direction in which the drum rotates so that rotation of the drum in one direction forces the batch toward the front end of the drum, and rotation in the opposite direction forces the batch toward the rear end of the drum, thereby aiding in obtaining a thorough mixing. A water pipe Ill extends axially of the drum and is provided with spray nozzles II which spray water to the batch as the drum is rotated. The water is carried in tanks which are not shown but which may be connected in any desired manner to the pipe l0 so that water can be delivered to the batch in the drum 2.

The drum is supported by rollers l2 and 13 which are mounted in the opposite ends of yokes II which extend transversely of and are supported on the truck chassis. The yokes II have flat bases l5 which rest on rubber pads l5 which 5 in turn are supported by a framework l1 secured to the truck chassis. Longitudinal movement of the yokes I4 is restrained by angle bars l8 as shown in Figure 1, and the yokes are restrained from movement transversely of the chassis by bolts l9 extending through the yokes l4 and angle bars.l 8.

The driving rollers l2 are secured to driving shafts and 26 which are connected by means of a shaft 21 and flexible couplings 28. In the disclosed embodiment only the rollers I! are driving rollers, the rollers l3 simply acting as supports for the rotatable drum. The driving shaft 25 is driven from an engine 30 through reduction and reversing gearing enclosed in a casing 3|. The reduction and reversing gearing will be described more particularly hereinafter. The rotation of the drum 2 may be reversed by operating a handle 32 located at the rear end of the drum. As the manual control for reversing the rotation of the drum is used only while the batch is being discharged, the operator will be standing at. the rear end of the mixer so that it is convenient to have the operating handle 32 located at that point. The operating handle 30 32 is connected to a rod 33 which extends lengthwise oi' the mixer and is slidably supported in brackets 34 secured to the yokes ll. The front end of the rod 33 is pivotally connected at 35 to a lever 36 which is rigidly secured at its opposite end to a pin 31 which extends into the gear casing 3|. The arrangement is such that upon rotation of the pin 31 a clutch shift lever hereinafter described, is shifted so as to reverse the rotation of the drum. A link 38 is rigidly secured at one end to the pin 31 and at its other end is pivotally connected to a rod 39 which connects with the governor 40 of the engine. 'A brake ll is connected through a lever 42 and a link 43 to the lever 36, the connection being 45 such that when the clutch shift lever 01' the reversing mechanism is in neutral position the brake is applied to the shaft 25.

It will thus be seen that by operating the handle 32 while the operator is standing at the rear of the mixer, the drum may be rotated in either direction, or if the clutch is thrown into neutral position, the rotation of the drum may be stopped and the brake applied.

Instead of reversing the rotation of the drum just described, provision is made for automatically and periodically reversing the rotation of the drum during the mixing operation. As previously described, this forces the material alternately toward opposite ends of the drum so as to obtain a thorough mixing of the material. The automatic reversing mechanism is illustrated in Figures 4 to 7 inclusive. The left hand end of the driving shaft 45 is splined for connection with the engine drive shaft so that the shaft 45 always rotates in the same direction. Rotatably mounted on the shaft 45 are two beveled gears 46 which are spaced apart and which mesh with a ring gear 41 on opposite sides thereof, the ring gear being secured to a shaft 48 mounted in bearings 48 and 58. A spur gear 6| is secured to the shaft 48 and meshes with a spur gear 52 secured to the shaft 25 which drives the rollers I 2, thereby causing rotation of the mixing drum. The driving shaft 45 is provided with clutches 55 and 56 as illustrated in Fig. 7 which may be shifted to the right or to the left in order to cause either one of the beveled gears 46 to rotate with the shaft 45. Any usual clutch mechanism which will cause either one of the beveled gears 45 to rotate with the shaft 45 may be employed and since this clutch mechanism is not claimed by applicant to be novel per se, a detailed description is not given herein. For causing either one of the beveled gears to rotate with the driving shaft 45, a clutch shift lever 51 is employed. As shown in Fig, 4 the lever 61 is keyed to the pin 81, one end 58 of the lever being forked to receive a pin 58 secured to a collar 68 which fits into a grooved ring 6| shown in Figure '7. The rear end 55 is forked to receive a pin 65 secured to a yoke 61 which can be oscillated to the right and to the left as viewed in Figure 4, the yoke being guided in its oscillation by arms 68 and 68 which slide in guides 18 and H, the arm 68 being provided with a groove I2 which receives a pin I8 screwed into the guide I8. It will be seen that as the yoke 51 is oscillated to the right or to the left from the position illustrated in Figure 4, it will shift the clutch 55 or 56 through the clutch shift lever 51 so as to cause either one of the beveled gears 45 to rotate with the shaft 45, thereby causing the shaft 25 to rotate in one direction or the other, depending upon which one of the beveled gears 46 is connected to rotate with the shaft 45.

In order to cause the yoke 61 to oscillate to the right and then to the left as viewed in Figure 4, so as to reverse the rotationof the drum, the right hand end of the shaft 45 is provided with a worm I which meshes with a worm gear I6 secured to a horizontally extending shaft 11. The shaft 11 has a worm I8 secured thereto which meshes with a worm gear I8 secured to a vertical pin 88, the pin being mounted in bearings 8| and 82. Secured to the pin 88 below the worm gear 18 is a cam 83. As the cam is rotated it causes oscillation of a yoke-shaped cam follower 84 alternately to the right and then to the left as viewed in Figure 4, the follower being provided with rollers 85 which contact with the cam. The follower oscillates in guides II and 86. A pin 88 extends through an opening in the follower 84 and is received in an opening 8| in the guide arm 68 of the yoke 61. The upper end of the pin 88 is formed in an eye 8| in which is received a pin 82 carried by a yoke 83 secured to the lower end of a plunger 84. A spring 85 surrounds the through manual control of the handle 32 as plunger and in the position indicated in Figure 6 forces the plunger downwardly so as to cause the pin 88 to enter the opening 8|. The upper end of the plunger 84 is provided with a washer and nut which are received in a hollow nut 86. When the pin 88 is received in the opening 8| as shown in Figure 6, the rotation of the drum is periodically and automatically reversed through the mechanism above described. However, if the nut 86 is screwed upwardly, it raises the pin 88 from the opening 8| so that even though the driving shaft 45 continues to rotate, it does not cause reversal of the drum rotation. When the pin 88 is raised from the opening 8|, the reversal of the drum is controlled manually by operating the handle 32. As above described, operation of the handle 82 causes a rotation of the pin 31, thereby shifting the clutch shift lever 51 and causing reversal of the drum rotation.

The arrangement of the reversing and reducing mechanism as illustrated in Figures 4 and 5 is such that a very great reduction is obtained in a small space. The arrangement is particularly adapted for use in connection with a truck mixer because the space available for such mechanism is small. The ring gear 4'! is formed with two crowns I8I and I82 so that the clutches 55 and 56 may be received within one of the crowns and the collar 68 and the end of the clutch shift lever 51 may be received within the other crown of the ring gear. The bearing 48 is so designed that the ring gear may be slid to a slight extent into the bearing in order to move the ring gear so that the clutch mechanism and shaft 45 may be removed as a unit from thecasing 8| without disturbing the other parts. For this purpose the casing 3| is provided at the bottom as viewed in Figure 5 with an opening I83 of sufficient size so that the clutch unit may be removed without disassembling it, the opening I83 normally being closed by a cover I 84.

Concrete or other material can be mixed more thoroughly by the method herein described than if the mixing apparatus were rotated continuously in one direction. The reversal of the mixing apparatus forces the material first to one end of the drum and then to the other end during the mixing process, even when water is being supplied to the batch, so that a very thorough mixing is obtained. When it is desired to change from automatic to manual control for reversing the mixing apparatus, it is only necessary to screw the nut 86 upwardly to disengage the pin 88 from the opening 8|. When it is desired to change from manual control to automatic control, the nut 86 is screwed down, thereby forcing the pin 88 downwardly so that when the pin comes directly over the opening 8|, it will be forced by the spring 85 into the opening and from that time on, the reversal of the drum will be automatic.

Although the drum illustrated in the preferred embodiment of my invention, is octagonal in cross-section, it will be understood that the reversal of the drum during mixing may be utilized irrespective of the shape of the drum.

Instead of using friction rollers for rotating the drum, as illustrated in the preferred embodiment, gears meshing with corresponding gears on the drum may be employed, or any other suitable means may be substituted.

I have illustrated and described the present preferred embodiment of my invention. It is to be understood, however, that the invention may be otherwise embodied or practiced within the scope of the following claims.

I claim:

1. A reversing mechanism, comprising a driving shaft, a driven shaft, a ring gear secured to the driven shaft, two beveled gears rotatable on the driving shaft, said beveled gears meshing with the ring gear at opposite sides thereof, clutches for causing either one of said beveled gears to rotate with the driving shaft, a pivoted clutch shift lever, a cam, gearing connected to the driving shaft for rotating the cam, a reciprocating follower, a reciprocating yoke connected to one end of the shift lever, and a spring-pressed pin connecting said yoke and follower.

2. A reversing mechanism, comprising a driving shaft, a driven shaft, a ring gear secured to the driven shaft, two beveled gears rotatable on the driving shaft, said beveled gears meshing with the ring gear at opposite sides thereof, clutches for causing either one of said beveled gears to rotate with the driving shaft, a pivoted clutch shift lever, a cam, gearing connected to the driving shaft for rotating the cam, a reciprocating follower, a reciprocating yoke connected to one end of the shift lever, a pin slidable in the follower, said yoke having an opening for receiving the pin, and biasing means tending to force the pin into the opening.

HAROLD E. McCRERY.

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