US 3842752 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent 91 Oct. 22, 1974 Harwick SPEED CONTROL  Inventor: Warren J. Harwick, Racine, Wis.
 Assignee: Rex Chainbelt, Inc., Milwaukee,
 Filed: Dec. 14, 1972  Appl. No.: 315,060
 US. Cl. 104/166, 104/147  Int. Cl B6lb 13/00, B6lk 7/18  Field of Search... 104/130, 147, 138, 165-168, 104/162,163, 172 B  References Cited UNITED STATES PATENTS 402,933 5/1889 Judson 104/166 423,871 3/1890 Judson 104/166 3,164,104 l/l965 Hunt 104/166 3,356,040 12/1967 Fonden 104/172 B 3,621,790 11/1971 Broome 104/147 R 3,626,859 12/1971 Bradbury 104/168 3,650,216 3/1972 Harwick 104/166 Primary ExaminerDrayton E. Hoffman Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak  ABSTRACT A speed control device for an operator-less, remotely controlled unit carrier system in'which a plurality of cars are driven over a trackway by means of thefrictional interaction of propulsion and reaction wheels. The device comprises a slidably mounted, springloaded probe normally extending some distance in front of each car but capable of being forced back relative to the body of the car by contact with the back of the preceding car. This probe is connected to either the propulsion wheels or the reaction wheels, whichever are mounted in the cars, such that their angle with respect to the wheels not mounted in the cars is varied from an angle giving a maximum speed to the car when the probe is maximally extended to an angle giving zero forward impetus to the car.
SPEED CONTROL FIELD OF THE INVENTION This invention relates generally to controlling the speed of the cars in an operator-less, remotely controlled unit carrier system in which a plurality of cars are driven over a trackway by means of the frictional interaction of propulsion and reaction wheels and, more specifically, to controlling the speed of the cars in a unit carrier system such as disclosed in commonly assigned U.S. Pat. Nos. 3,621,790, 3,626,859 and 3,650,216.
BACKGROUND OF THE INVENTION In a friction-powered unit carrier system such as is disclosed in the above-metnioned patents, a plurality of independently powered cars are driven over a trackway at high rates of speed. It is therefore desirable .to have some means of controlling relative speeds to reduce both the frequency and the impact of rear-endcollisions. Also, in a queing situation such as is discussed in commonly assigned U.S. Pat. No. 3,626,859, it is desirable to have an automatic means for rotating the car-mounted wheels to an angle such that no motive force is transmitted to the cars when each car is touching the rear of the car ahead of it, then rotating the wheels to an angle producing forward motion when the car in front moves forward.
SUMMARY OF THE INVENTION The present invention is designed to satisfy the foregoing desidarata in a simple, reliable fashion. Devices according to this invention include a slidably mounted, spring-loaded probe normally extending some distance in front of each car but capable of being forced back relative to the body of the car by contact with the back of the preceding car. This probe is connected to either the propulsion wheels or the reaction wheels, which ever are mounted in the cars, such that their angle with respect to the wheels not mounted in the cars is varied from an angle giving a maximum speed to the car when the probe is maximally extended to an angle giving zero forward impetus to the car. The connection may be such that the reaction wheels actually give reverse impetus to the car if the probe is pushed back still farther.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the underside of a unit carrier system car incorporating one embodiment of the present invention, showing the car-mounted wheels turned to an angle giving the car forward drive.
FIG. 2 is a plan view of the underside of the unit carrier system car shown in FIG. 1 with the car-mounted wheels turned to an angle giving the car no forward drive.
FIG. 3 is an end view of the car shown in FIG. 1.
FIG. 4 is an enlargement ofa portion of FIG. 1, showing the mounting of one of the car-mounted wheels in further detail.
FIG. 5 is an enlargement of a portion of FIG. 2, also showing the mounting of one of the car-mounted wheels in further detail.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT While the present invention is equally applicable to the situation where the driving wheels are mounted between the rails of the trackway and the reaction wheels are mounted on the cars, on the one hand, and to the situation where the driving wheels are mounted on the cars and the reaction wheels are mounted between the rails of the trackway on the other, it was first conceived in the former environment, and it will be described herein in that environment. However, it should be borne in mind that the important thing is the means for varying the attack angle of the car-mounted wheels and not whether it is the drive wheels or the reaction wheels the angle of which is being varied.
FIGS. 1, 4, and 5 show a portion of a drive tube 10 superimposed in phantom lines on the bottom of the car 12 depicted therein. This is to permit better visualization of the attack angle a, which is expressly shown in FIG. 4. When this angle is zero, no impetus is imparted to the car, and when it is more than zero, a forward impetus is imparted to the car. While the embodiment described herein does not provide for an angle a of less than zero, it could be readily adapted to provide for negative attack angle, and, if it were so adapted, a backwards impetus would be imparted to the car. The interaction of the drive tube and the reaction wheels,
which is more fully described in commonly assigned U.S. Pat. Nos. 3,621,790 and 3,650,216, does not, per se, form any'part of the invention herein.
FIGS. 1 and 4 show the probe 14 fully extended. As may best be seen in FIGS. 4 and 5, the probe 14 is slidably mounted in a bearing 16 which depends from the front bottom of the car 12. The probe 14 is also slidably mounted in a bearing 18 which depends from the bottom of the car near the center thereof and a bearing 20 which depends from the bottom of the car just rearward of the extreme position assumed by the rear pivot 22. This latter'relationship is best seen in FIG. 2. The distance that the bearings depend beneath the bottom of the car is such that the probe 14 is at the same level as the axes of the reaction wheels 24, as may be seen in FIG. 3.
Depending from the rear of the car is a stop plate 26 which serves two purposes. First, its forward face serves to limit the travel of the probe 14 so that the attack angle a cannot take on a negative value. Second, as may be seen in FIGS. 2 and 5, its rearward face serves as an engagement surface for the probe on the front of the following car, thereby permitting the probe to serve as a speed-control device as taught herein. Obviously, if the rear of the body of the car extends low enough, no separate stop plate is required, the body of the car serving the same function.
Mounted on the probe 14 are a front pivot 28 and a rear pivot 22. Each pivot is connected to a linkage arm 30 having a slot therein at the end connected to the probe 14 to permit lost motion as the probe 14 moves linearly to the rear and the linkage arm pivots around an axis coextensive with the axis of a pin 32 mounted on the bearing 34 supporting the reaction wheel 24. The linkage arm30 and the pin 32 are solidly joined together so that the rotational motion .of the linkage arm 30 is transmitted to the bearing 34. The linkage arm 30 extends beyond the pin 32 for some distance and in connection at the far end thereof to a spring 36 which biases the linkage arm 30 in the clockwise direction, thereby biasing the probe 14 towards its fully extended position. The spring 36 is connected to the underside of the car 10 in any suitable fashion.
The reaction wheels 24 are mounted for rotation about bearings 34, and each unit comprising a reaction wheel 24 and a bearing 34 is mounted for a limited rotation about the axis of the pin 32, which is perpendicular to the body of the car 10. In other words, the attack angle a may be varied from zero to a pro-selected maximum. The mounting of the units comprising a reaction wheel 24 and a bearing 34 may be in any conventional manner. For instance, the mounting stands shown in commonly assigned US. Pat. Nos. 3,621,790 and 3,650,216 may be easily adapted for rotation and for mounting on the bottom of the cars rather than in the trackway, as shown therein.
FIGS. 1, 2, and 3 also show support wheels 38, guide probes 40 and rails 42, the purpose and function of which are explained in detail in commonly assigned application Ser. No. 306,487, tiled Nov. l4, 1972, and accordingly need not be explained in further detail here.
CAVEAT While the present invention has been illustrated by a detailed description of a preferred embodiment thereof, it will be obvious to those skilled in the art that various changes in form and detail can be made therein without departing from the true scope of the invention. For that reason, the invention must be measured by the claims appended hereto and not by the foregoing preferred embodiment.
What is claimed is:
l. A device for controlling the speed of a car which is driven by the frictional interaction of a propulsion wheel and a reaction wheel, one of which wheels is rotatably mounted on a bearing on the underside of said car and the other of which wheels is rotatably mounted in a trackway over which said car is driven, said device comprising:
i. a pivot means permitting the one of said wheels which is mounted on the underside of said car to rotate about an axis which is perpendicular to the body of the car;
2. a probe which is slidably mounted relative to the body of said car and laterally spaced from the axis of pivot means;
3. a linkage arm operatively connecting said probe to said pivot means, said linkage arm being integrally connected to said pivot means intermediate the ends of said linkage arm and having a slot therein located where said said linkage arm is connected to said probe to permit lost motion as said probe moves linearly and said linkage arm rotates about said pivot means; and
4. a spring connecting said linkage arm to said car on the side of said linkage arm opposite from said probe so as to bias said linkage arm in a direction which in turn'biases said probe to normally extend in front of the body of said car,
whereby the linear movement of said probe causes the rotational movement of said wheel about said pivot means.
2. A device as claimed in claim 1 further comprising a stop plate, one side of which may serve as an engagement surface for a probe on the'front of a second, similar car following said car, whereby the speed of said second car may be controlled.
3. A device as claimed in claim 1 wherein said reaction wheel is mounted on said car.
4. A device as claimed in claim 1' wherein said pro- 3,842,752 October 22, 1974- Patent No. Dated' L Inventor) Warren J. Harwmk It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown-below:
In The Heading;
Y The Assignee's name ipcbr r ec h Shoxild be:
Signed and sealed this 7th day of January 1975.
(SEAL) Attest: I v
McCOY M. GIBSON c. MARSHALL DANN attesting Officer Comissioner of Patents 'ORM PO-OSO (10-69) useoMM-oc eos1u-poo U.S GOVERNMENT IR NT NG OFFICE: 869" 93 o