US1886253A - Multiple plunger lift - Google Patents

Description

Nav. 1, 1932. c. sTUKENBoRG MULTIPLE PLUNGER LIFT Filed Feb. 24. 1930 Ufa/iwf Nov. 1, 1932. l.. c. sTuKENBoRG MULTIPLE PLUNGER LIFT 2 Sheets-Sheet 2 Filed Feb. 24, 1930 di! :fe/Mar -Lazzf Jia/remar ya? C//a/weyf atented New., l, i932 intenta LOUJIS U. ST'UKEIQ'BORG, OF MMPHIS, TENNESSM, ASSIGNOR T0 STANDARD 'LIFT COMPANY, OF MEMPHIS, TENNESSEE, A CORPORATION 0F DELAWARE MULTIPLE IPLUNGER LEFT application mea rebruaw 24, i930. serial np. ascesa.

An object of my invention is to provide a lift for busses and other large vehicles, the lift being of the multiple plunger type and being comparatively simple and durable and (g1 inexpensive to manufacture.

A further object is to provide a lift consisting of a vehicle support with a plurality of `lift devices such as those of the hydraulic type for lifting the lvehicle support7 each lift device being 4preferably secured to the vehicle support for raising the same.

A further Objectis to provide a means for synchronizing the motion of the plurality of lift devices regardlessof the weight distribution on the vehicle support, such synchronizing means being of a mechanical nature for positively insuring equal travel of each of the lift devices to prevent buckling or twisting of the vehicle support. l

A further object is to provide in a multiple Aplunger lift having a notor for each lifting device, a safety means to prevent overloading of one or more of the motors so as to preventdamage to the motors due to overloading the vehicle support and distributing the weight a on the support in an exceptionally uneven way.

Still a further object is to provide a series of plunger lifts with a motor for each lift and an overload relay for each motor, the relays` being so connected that all of the motors are thrown out 4of circuit when any one of them is overloaded. v

With these and other objects in view. my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings. Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give a full understanding of the invention both from its structural and functional standpoints. Accordingly, I have ilment of the invention in the accompanying drawings in which:

Figure 1 is a plan view of a multiple plunger lift embodying my invention.

Figure 2 is a sectional view of the same on the line 2 2 of Figure 1. i

Figure 3 is a vertical sectional view on an enlarged scale and taken on the line 3 3 of Figure 2.

Figure 4 is a sectional view on the line 1 -ll: of Figure 3.

Figure 5 is an electricaldiagrammatical gg@ View of the lift motors and controlling cir- .cuit therefor.

Figure 6 is a sectional view through an overload relay for one of the motors as taken on the line 6-6 of Figure l and Figure 7 shows a fragmentary part of Figure 6 with the parts in a dierent position.. s

0n the accompanying drawings l have used the reference numeral 10 to indicate the to siderails of a vehicle support. rlhe rails l0 are oii substantial length for coaction with a long vehicle such as a motor bus. A plurality of lift devices each including a cylinder l2 and a plunger la are associated with the te side rails 10 for lifting them.

A head 16 is secured to each plunger 1d and extends between the side rails 10. 'llhe heads 16 are connected with the side rails by means of cap screws 18 (see Figure 3)or may be ec welded to the side rails as desired.

The specic construction of the lifting (levices is set forth in detail in my co-pending application Serial Number 366,889, filedy May 29, 1929. riefly each lift device includes a e@ partition 20 in the plunger 14 to which an oil pump 22 is secured. 'llhe oil pump 22 yis adapted upon operation to draw oil through a strainer 24 from the interior of the plunger 14 which constitutes an oil reservoir and dis- @u charge it through an opening 26 below the partition 26. A shaft 28 extends from the pump 22 to an electric motor 30 mounted in the top of the plunger 14. Upon operation of the motor 30, oil will be pumped fromthe top @5 of the partition 20 to the cylinder 12 below the partition for raising the supporting rails lustrated a preferred and desirable embodi- 10 When it isudesired to lower the supporting rails, oil may be released from below the parm@ tition to the reservoir space above the partition by opening a normally closed release valve 32 located in each plunger 14.

vA rod 34 extends upwardly from each release valve 32 and is adapted to be engaged by a pivoted arm 36 which Iin turn is operated by a rock shaft 38 and handle 40. Thus it lil will 'be seen that when the release valves 32 are opened, the weight of the lift will force oil from below the partitions 20 to the reser- ,voir spaces above the partitions.

seat for the differential of thebus. The -re-y maining angles on this plate are for reinforcing purposes. An adjustable seat for the differential is provided in the form of cross bars 46 and angles 48 welded together. This device is sldable with respect to the side rails 10. Stepped castings 50 may be provided for the front axle of the bus and these are preferably connected together with a tie rod 52. This device is also slidable longitudinally with respect to the side rails 10.

When more than one plunger is used in a lift of the character herein disclosed, the

problemof.- causing all of the plungers 14 to move with equal speed and to equal heights is involved. The problem must be especially overcome where the weight distribution of the vehicle on the side rails 10 is uneven. In the present instance I have provided for synchronization of all of the plungers 14 in the matter to now be described. .Y

A rack bar 54 is secured adjacent each head 16 of the plungers 14 to one of the side rails 10"as best shown in Figure 3. A casing-56 is provided for each rack 54 and may be supported relative to the cylinder 12 by means.

of encircling bands 58 and clamp bolts 60 and 62. A pair of bearing brackets 6'4 is secured to each cylinder 12 as best shown in Figure 4 and the rack bar 54 extends between these brackets. A pinion 66 vis mounted between the brackets and secured to a stub shaft 68. The stub shafts 68 are. connected by` couplingr members 70 with intermediate shafts 72. The pinions 66 mesh with the rack bars 54 whereby it will be obvious that a movement of any one of the rack bars 54 will cause corresponding movement of the other rack bars and consequent equal movement of all'the lift plungers 14.

A roller 74 mounted on a stub shaft 7 6 serves to maintain the rack bars in mesh with the pnions. A cover 7 8 is provided for each pinion. A. pit is provided extending longitudinally with respect to the lift and the intermediate shafts 72 as well as the pinions 66 and associated mechanism are located in this it which may be suitably covered as desired A drainv pipe.82 is provided for the pit 80.

Lesesaal In connection with eachlmotor 30 I provide a relay switch indicated. generally by the reference character A. In connection with all the motors a main switch B and a manually operable starting and stopping switch C is provided. Each relay switch A includes a pair of contacts 84 held in closed position by cams 86 which in turn are held in the position shown in Figure 6 by thermolstatic strips 88. Heating coils 90 are provided or exing the thermostatic strips 88 to the dotted line position'(or the full line position shown in Figure 7) whereupon the resilient contact strips 84 will spring apart as shown in Figure 7. A reset cord 92 is prpvided for each relay switch and these cords extend over pulleys 94 and are connected with a-reset cord 96. The reset cord 96 may be connected with a bracket 98 adjacent the switch C'for convenience of the operator in resetting the overload relays. l

The main switch consists of a plurality of switch arms 100 coactable with contacts 102 upon an armature 104 being drawn toward an electro magnet 106. The manually operable starting and stopping switch C includes a starting button,108 and a stopping button 110. The button 108 is held in extended position by springs 112 and contacts with an armature arm 114 when pressed inwardly.

The stopping button 110 is connected with the armature 114 which is held normally in. one position by aspring 116. An electro magnet 118 is provided for holding the armature 114 in on position after the button 108 has been pressed.

Practical operation In the operation of my device when it is desired to actuate the lift for raising a vehicle,

the button 108 is pressed which establishes a circuit from a supply wire 120 through the button 108, the button 110, the electro mag'- nets 118 and 106, all of the contacts 84 of the relay switches A and back through a supply wire 122. The electro magnet 118 will then .hold the stopping button 110 closed even after the starting button 108 is released. The current from the wire 120 will then iow through the right hand switch 100 and through the stopping button 110 due to the pull of the electro magnet 106 on the armature 104 so that the starting button I108 when re leased does not break the circuit.

The pull of electro magnet 106 on the armature 104 will also close the left and center switch arms 100 'for establishing a circuit through all o the motors 30. f

If the load is so distributed that it is `greater on one motor than on another, then the other motors @through the rack bar and pinion interconnections) will assist the loaded motor. In event that one .motor overloaded to lo enferheatedS im i itil@ ticular relay A to iex it will cause the heatin coils of its pare thermostat stri s 88 and open the electric circuit throught e electro magnets 106 and 118 whereupon the main switch will be opened by the spring 124 lfor cutting off the current supply to all of the motors 30 and the armature 114 will be released in the switch C to restore this switch to normal position. After conditions have been adjusted for proper operation of the lift, the reset cord 96 may be pulled for resetting the relay which was opened by the overload.

Some changes may be made in the c`onstruction and arrangement of the parts of my device without de arting from the real spirit and purposes o my invention, and it is my intention to cover by my claims, any modified forms of structure of use of mechanical equivalents, which may be reasonably included within their scope.

I claim as m invention:

1. In a multiple plunger lift, a plurality of cylinders and a plurality of plungers constituting lift devices, a vehicle support to be lifted by all of said devices and an operative connection between said plungers for synchronizing their lifting motion regardless of the Weight distribution on the vehicle support, said operative connection comprising a bracket supported on each cylinder, an

equalizer shaft journalled in said brackets, a rack bar movable with eachv lunger and each adjacent one of said brac ets and an equalizer pinion meshing with each rack bar and connected with said equalizer shaft.

2. In a multiple plunger lift, a plurality of cylindersl and a plurality of plungers constituting lift devices, a vehicle support to be lifted by all of said devices and an o erative connection between said plungers or synchronizing their lifting motion regardless of the weight distribution on the vehicle support, said operative connection com rising a bracket supported on each cylin er an equalizer shaft journalled in said bracixets a rack bar movable with each lunger and each adjacent one of said brac ets, a rack bar casingv supported on each cylinder for encasing said rack bars and an equalizer pinion meshing with each rack bar and connected with said e ualizer shaft.

LOUI C. STUKENBORG.

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