US2943782A - Refrigerating apparatus - Google Patents

Description

R. M GREGOR REFRIGERATING APPARATUS July 5, 1960 s Sheets-Sheet 1 Filed May 29, 1957 lllllLL IIIIIIIIII WAR.

R J m w July 5, 1960 R. MCGREGOR REFRIGERATING APPARATUS 3 Sheets -Sheet 2 Filed May 29, 1957 INVENTOR. Ralph 771 r yor BY 5M 9, HIS ATTORNEY July 5, 1960 R. MCGREGOR REFRIGERATING APPARATUS 3 Sheets-Sheet 3 Filed May 29, 1957 INVENTOR. Ralph 771 rq gqr ms ATTORNEY States. Patent This invention relates to refrigerating apparatus and vidcl'with adrivingi liig 30which is adapted a diivingly engage alug 32 carried by the crank element 26 It will be noted that the construction and arrangement of the lugs 30 and 32 is such that a limited amount of relative rotation can take place betweenthecam plate 18 and the crank portion 26. It will also be noted that the lug 32 is adapted to engage the inclined cam surface 40 provided on the cam plateZS with the result that relative rotation between the cam plate 28 and the crank element 26; serves to axially move the crank element 26 on the shaft 18.' This movement can be obtained by reversing thedirection of rotation of the motor andcauses a change'in thehead clearance adjustment which, in turn,

. causes a change in the output of the compressor. In

more particularly to a variable output refrigerant com pressor .It is'an object'of this invention to provide'a refrigerant compressor or the like having a new and im'proved arrangement for varying its output so as to maintain a proper balance between the compressor output and the refrigeration requirements, 1

It is another object of this invention to provide acompressor-having an output varying means which automatically chan'ges the output of the compressor in response to a change in the direction of rotation of the compressor operating'means. Q

,Stillapother object of this invention is to provide a compressor inwhich the head clearance may be adjusted so as to adjust the effective-capacity of the compressor.

Further objects and advantages of the present invention willbe apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a vertical sectional view showing an axial type compressor embodying theinvention;

Figure 2 is a fragmentary vertical sectional view showing the arrangement of the parts when the compressor operates at a reduced capacity;

Figure 3 is an elevational view showing a portion of the wobble plate assembly; 7

Figure 4 is an end elevational view showing the head clearance adjusting cam;

Figure 5 is a side elevational view of the member shown in Figure 4;

Figure 6 is a schematic circuit diagram showing the arrangement for reversing the direction of rotation of the motor for varying theoutput of the compressor;

Figure 7 is a fragmentary sectional view showing a modified arrangement for varying the head clearance adjustrnent; and 1 Figures 8 and 9 are similar to Figures 3 and 4 but show the modified head clearance adjusting means.

Referring now to the drawings wherein a preferred embodiment of the invention has been shown, reference numeral 10 generally designates a motor compressor housing which serves to enclose an axial type compressor generally designated by the reference numeral 12 and a driving motor including a motor stator 14 and a motor rotor 16.

The motor rotor 16 is directly secured to the one end of.

the main drive shaft 18. The shaft 18 has its one end journalled in a main frame 20 and has its other end journalled in the cylinder block 22 as shown. The compressor is of the axial type wherein a wobble plate element 24 is journalled on an angularly disposed bearing element or crank portion 26 which is normally adapted to be driven in unison with the shaft 18 by means of the head clearance adjusting cam plate 28 which is keyed to the shaft 18 so as to rotate with the shaft 18 at all times. The cam plate 28 as best shown in Figures 1. 4 and 5 is pro- Figure 1 of the drawinggthe parts are shown occupying the position which they occupy when the compressor is operating at maximum capacity whereas Figure 20f the drawing shows the relative position of the parts when-the compressor operates at its capacity.

The compressor inlet a'ndoutlet valves are of the type more fully disclosed in copending United States applications S.N. 640,025, filed February 13, 1957,v and SN. 430,768, filed May 19, 1954, now Patent No. 2,825,499, to which reference is hereby made for a more complete disclosure of the compressor per se. The output varying means shown herein is equally applicable to pumps handlingliquids-a'nd to pumps driven lay-externally disposed prime movers. In 'order to simplify the disclosure only the one pump piston 42 has' been shown whereas the compressor has five uniformly spaced pistons. t 2

By virtue of the above described arrangement, the capacity ofthe compressor may be changed merely by reversing the direction of rotation of the main drive shaft 18. Thus, when the drive shaft 18 rotates in the one direction, the driving lug 30 is adapted to engage the end surface 44 of the complementary lug 32 formed on the wobble plate driving crank 26 and, when the motor operates in the opposite direction, the lug 30 will engage the surface 46. Any conventional means may be provided for reversing the direction of the drive motor. For purposes of illustration, there is shown in Figure 6 a circuit diagram of one form of motor reversing system. As shown in Figure 6, the motor stator 14 includes a main winding 50 and a starting winding 52. These windings are adapted to be connected to a power source, designated by reference numeral 54, by means of a main control switch 56. The direction of rotation of the motor is controlled by means of a polarity reversing switch 58 which is used for connecting the starting winding 52 to the power supply. The switches 56 and 58 may be operated manually or automatically so as to vary the output of the compressor in accordance with refrigeration requirements. A conventional starting winding control 60 serves to deenergize the starting winding when the motor comes up to speed in accordance with standard practice.

' In Figures 7, 8 and 9 of the drawings, there is shown a the elements 26 and 28 are controlled by means of a torsion spring 7 0 which normally biases the parts to the position in which the compressor has minimum head clearance and consequently maximum output. In the event that the load on the compressor becomes excessive either because of an excessive increase in the condenser pressure or because of an excessive increase in the speed of the driving element, the wobble plate operating member 26 will shift relative to the cam plate 28 so as to automatically increase the head clearance adjustment and thereby reduce the output of the compressor. The spring is so arranged that the compressor normally operates at maximum capacity but, as the load on the compressor increases, the spring tends to yield so as to allow the element 26 to Patented- July 5,1960

shift. relativeto the elementZS in a direction whereby the head clearance increases.

Whereas Figure 1 of the drawing shows a compressor operated by means of a reversible motor, it is apparent that certainnaspects-of the invention wouldbe equally applicable to an arr ngement in which some other form of prime mover would be used for driving the compressor. Thus, the arrangement shown in Figures 7, 8 and 9 is particularly applicable to a compressor driven by means of a carengineor the like wherein the speed of the compressor drive shaft would be varied without any relation to the compressor requirements. In systems of this latter type, it is: desirable to provide means for automatically reducing thescapacity of the compressor at high engine speeds when the compressor-has a, capacity greatly in excess of the capaeitytrequiredat a given time.-

While the. embodiment of, the invention as herein disclosed constitutes a preferred form, it is to be understood of: saidelements. axially on said. shaft, said last; named. meanscomprising an inclined cam surface on one of said elements and a cam follower on the other of said elements slidably engaging said cam surface.

2. In combination, a pump including a drive-shaft hav- 4 ing an-ofiset crank'portion, a wobble plate assembly'disposed on said crank portion, a cylinder block having a plurality of cylinders parallel to the axis of rotation of said shaft, piston means operatingjn said cylinders and driven by said wobble plate assembly, said assembly comprising a pair of relatively rotatable elements, means for securing one of said elements to said shaft, and means responsive to relative rotation of said" elements for shifting the other of said elements axially on said shaft 3. In combination, a pump including a drive shaft having anofisetcrank portion, a. wobble plate assembly disposed on said crank portion, a cylinder block having a plurality of cylinders parallel to the axis of rotation of said shaft, piston, means operating in said cylinders and driven by said wobble plate assembly,said assembly comprising a pair of relatively'movable elements, one of said elements having an axially extending driving lug formed thereon and the other of said elements having a circularly disposed inclined cam surface arranged to engage said driving lug; whereby relativev rotation between said elements produces axial displacement of said elements, means fonlimiting the extent of relative rotation of said elements, and meansifor reversing the direction of rotation of said driveshaft.

" References Cited in thefile of this patent UNITED STATES PATENTS 1,718,525 Casey June 25, 1929 2,283,774 Thompson May 19,1942 2,402,244 Elberty June 18, 1946 2,573,863 Mitchell Nov. 6, 1951 2,741,985 Parsons Apr. 17, 1956 2,792; 7-86' Nielsen May 21, 1957 2,847,966 McIntosh Aug. 19, 1958

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