US2546585A - Grease pump - Google Patents

Description

4 Sheets-Sheet 1 GREASE PUMP H. B. CALDWELL /s IA /2/ /a March 27, E951 Filed 4sept. 9, 1948 3 a lm 5 /A4 d 2 wn. a 4 @u March 2?? H951 H. E. CALDWELL. 25469535 GREASE: PUMP Filed sept. `9, 1948 44 sheets-sheet 2 March 27, 1951 H. B. CALDWELL 2,546,585

GREASE PUMP Filed Sept. 9, 1948 4 Sl'xeeibS-Sheetl 5 81- fl' *a FIG .7.

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March 2 7, 195

Filed Sept. 9, 1948 H. B. CALDWELL 2,546,585

GREASE PUMP 4 Sheets-Sheet 4 @ifm V Patented Mar. 27, 1951 2,546,585 GREASE PUMP Harry Balshaw Caldwell, Penketh, England, assignor to Electro-Hydraulics Limited, Warrington, England, a company of Great Britain Application September 9, 1948, Serial No. 48,351 In Great Britain August 20, 1947 5 Claims.

This invention relates to grease pumps and concerns more especially the use of a pump in a greasing system, wherein diierent parts of a machine have to be lubricated from a single point. As an example of machines in which this type of system is particularly useful it will be appreciated that the invention is applicable to machine tools, motor cars and parts thereof.

In a known system a grease pump is provided with a single outlet which is branched out into a number of pipes leading to the several parts of the system to be lubricated. This arrangement has the disadvantage that the pipes having the lowest resistance to flow of grease, either due to short length thereof or to the pipe being unobstructed, will receive most of the lubricant from the pump. The parts of the system remote from the pump outlet or pipes having a higher resistance to ow of lubricant leading to such parts Whether clear or containing a foreign matter .capable of resisting the flow of lubricant and even becoming plugged so as to stop said flow, may often remain without lubricant although the grease .pump has been actuated. Increased resistance against the pressure of the pump in some lines may not necessarily be detected since the other lines of low resistance or unobstructed lines, will take up the lubricant, and thus there is always the possibility of a breakdown in the lubricating of the necessary parts.

It is an object of the present invention to provide a grease pump which, when operated, will allow the pump outlet to be connected in a predetermined sequence to each of the pipe lines leading to the parts to be lubricated.

According to the present invention a grease pump comprises a lubricant receiving cylinder within the pump body, a piston slidable in said cylinder, a valved outlet from said cylinder communicating with a pipe line selector within the pump body, which selector on actuation of the piston is rotatable through a pre-determined distance to place the outlet from the selector successively in communication with one of the pipe lines leading to the parts to be lubricated, so that lubricant is forced into each pipe line in turn.`

Preferably the selector is moved through a predetermined distance positively by actuation of the piston through, for example, a pawl engaging a ratchet mechanism fast with the selector. Preferably also the piston is actuated against the action of a spring, whilst the outlet from the cylinder is controlled by a non-return valve. The ratchet teeth are provided preferably in number equal to the number of pipe lines.

The invention is illustrated in the accompanying drawings in which Figure 1 illustrates one form of pump, Figure 2 being a section on the line A--A Figure` 1. `Figure 3 is a longitudinal section of a modified form of pump, Figure 4 being a part-section taken at right angles, and Figure 5 a sectional plan view on the line 5-5 Figure 3. Figure 6 is a similar View on the line S-B Figure 4, Figure 7 being a part view similar to Figure 3 but with the piston in the operative position, Figure 8 a sectional plan on the line 8-8 Figure '7, Figure 9 is an elevational view partly in section showing a spring loaded lubricant accumulator in place, and Figure l0 is a similar view of the pump equipped with a transparent cover for rendering the indicia on the ratchet wheel visible.

Referring to the construction shown in Figuresl and 2 the pump body I has slidably mounted in its bore 2 a piston 3 which is rendered fluid-tight by any suitable means for example a suitable packing or fit. The piston 3 terminates in a ilanged head 4, outside the body, which head ,constitutes the piston operating portion and the piston 3 is actuated against the load of a spring 5 for example by hand or foot pressure. The cylinder is provided with an inlet 6 to enable 1ubrieant to Venter either under suction when the piston is moved, or by the provision of a low pressure lubricant accumulator such as shown in Figure 9, to feed the pump cylinder according to requirements. The cylinder is formed with a large recess i' into which the lubricant is fed from the inlet 6, the recess ,communicating through a nonreturn valve 8 biassed to closed position by a spring 9, through a passage I0 into the centre of a stepped bore II within the pump body. Mounted within the smaller diameter of the said bore is a rotary selector I2 which carries in any convenient manner, for example by brazing, a ratchet wheel I3 which is capable of rotation within the larger diameter part of the stepped bore. The number oi ratchet teeth provided on Ithe wheel I3 correspond to the number of outlet ports in the pump body, each of which ports communicates with a pipe line leading to a part to be lubricated. The passage It communicates through a port I4 into a U-shaped bore I2' of the rotary selector I2, which bore allows communication from the passage to one of the outlet port holes, two of which are shown at I5 and I6 (Figure 2) and thence to the pipe lines, which serve as means to carry the lubricant to the required lpoints. A plate I8 is arranged to hold in position double conical hollow sealing washers I9 and is secured onto the pump body I by bolts 2B. Pivotally mounted upon the piston rod is a pawl 2l which is adapted to engage with the ratchet wheel I3, the pump casing being enclosed by a cover 22 provided with suitable packing 23.

It will be appreciated that by moving the piston 3 against the action of its spring 5, that is to say into the cylinder I the piston forces lubricant past the non-return valve 8 ,into the passat@ ill leading to the rotary selector l2, past one of the ports I5, I il into one of the outlet pipe lines El. When pressure on the piston is released the spring 5 returns the piston to its former position and the return stroke of the piston allows the pawl 2| to drive the ratchet wheel la conveniently by one tooth pitch; thus the rotary selector l2 is rotated by the Same amount, thereby bringing the U-shaped bore l2 therein into communication with the next pipe line in succession.

In order to provide an indication for the outlet pipe connected to receive lubricant, the ratchet wheel and the pipe lines can be numbered, and an eccentric or cam may be provided on the selector with a cable connecting the eccentric or cam to a remote indicator. li desired, the pump body may be provided with an opening having a transp-arent cover il, so that the nuinber on the ratchet wheel is rendered visible as shown in Figure l; moreover the pipes il may be non-metallic and/or transparent so that pumping action can be checked from outside and also to guard against the effects of vibration. As has been stated above the lubricant may be fed to the pump cylinder by a low pressure lubricant accumulator' and if this arrangement be provided the accumulator may contain a spring-loaded piston thus ensuring that the pump is loaded. One form or" a low pressure lubricant accumulator is shown in Figure 9 wherein 5l represents the accumulator cylinder fastened to the pump body I by means of a threaded stem which nts in the inlet E and places the accumulator cylinder in communication with the cylinder of the pump body The accumulator cylinder Si is closed by a threaded cap 32 and has located therein the piston or plunger t normally under a downward pressure from a coil spring '33 interposed between the plunger and the cap $2. Suitable packing secured to the plunger t by means o a central bolt and nut E5 insures against leakage of lubricant past the plunger 65. Referring now to the modified form shown in Figures 3 to 3 parts similar to those provided in the previous construction are given the saine reference numerals. In the pump body l again slides the piston 3, a sealing gland 5 being provided to seal the port through the pump body. Fixed to the piston 3 by means of washer and circlip E5 is a collar 2S having a radially projecting arm as will seen i'r Figure 3. inner end ol the piston 3 slides in the bore 2 which is provided with apertures 2l. Carried by or integral with the cylinder l is the rotary selector !2 and ratchet wheel i3, the outlet of the cylinder being closed again by the non-return valve 3 and spring An aperture 28 in the cylinder i and al i2 coin Seatea single outlet 2c which may be provided with a washer su or a rlanged tube resiliently backed up, for example, by one or more rubber rings. *lhe selector carries a further dummy port and washer on its opposite side to prevent tilting when under pressure. The pump body l is provided with an inlet connection G and is closed by a cover Si which has a number ol out-- lets il preferably corresponding to the number of teeth or the ratchet wheel i3. The outlets il carry on their inner ends double conical hollow sealing washers ill which are held in position by the securing nuts 2D screwed into the end plate I3, which in turn is retained in the body I by a circlip l Surrounding the piston is' and the boreiis lever in the form ci a yoke the shape 4 of which is seen more particularly in Figures 4, 5 and 6. This yoke S2 is pivotally mounted intermediate its ends on bolts 33, 35i screwed into the pump body I, and is also pivotally connected at one end to a pin 35 of a trunnion 36 as shown in Figure 3. A spring 3? is held in position by a spring support 38 which in turn is in fixed connection with the pump body I through a bracket 3Q and nut lill. The said spring 37 biasses the trunnion 3% into the position shown in Figure 3, the load of the spring being adjustable by means of a bolt fil screwing into the pump body and a lock nut 42. Fixed to the yoke 32 is a pin 43 to which is rotatably mounted the pawl 2l which may be held in engagement with the ratchet teeth by any suitable spring (not shown). A spring M biasses the collar 26 and with it the piston 3 into the position shown in Figure 3 and the other end of the spring 44 rests on the ratchet wheel i3, the ball race or a number of washers l5 being interposed between the Spring and the ratchet wheel so that movement of the ratchet wheel does not increase the tension of the spring. The piston is again shown with an actuating knob l although it will be appreciated that the piston could be operated by other means such, for example as being operated through a motor. As will be seen from Figures 3 and 7 the inner surface of the yoke 32, adjacent the radial arm on collar is arcuate in vertical cro-ss section, so as to eiect a cam action with said arm as the piston and collar are moved inwardly as in Figure 7. rlhis cam action causes the yoke 32 to rock clockwise on the bolts 33, 34, elevating the trunnion 3G against the bias of spring '31 and positioning the pawl 2| for engagement with the succeeding tooth of the ratchet i3. Upon .return of the piston to its original position, the spring 3l' rocks the yoke 32 counterclockwise and with it, the pawl 2i which, through ratchet I3, rotates the selector l2 to the next position. Before further describing the operation of this modification it must be stated that in Figures 7 and 18 the piston 3 and yoke 32 are shown in vthe depressed position that is to say the position in which they are moved to deliver lubricant.

The system works follows: the bore of the pump body is lled with lubricant through the connection 6 by known means, for example an accumulator with a spring-loaded piston. When the piston 3 is depressed the lubricant in the cylinder bore between the piston 3 and the nonreturn valve 3 will be forced through the aperture 23 and port 29 into a pipe line Il. As the collar 23 is xed to the piston 3 on movement of the piston the radial arm 28a of collar 26 Will carry the yoke 32 with it thus pivoting the yoke around the bolts 34 carrying the trunnion 36 into the pump body. When the load on the piston is removed the spring d4 will return the piston to its original position and the spring 3l will return the trunnion 35 to its original position, the latter carrying the yoke 32 with it due to its connection by the pin 35. The tip of the pawl 2| will advance by one tooth of the ratchet vI3 during the upward stroke of the piston 3 as shown in Figure 8, and when the trunnion 36 returns the yoke 32 due to the action of the spring 31 the pawl 2i will pivot round its pin t3 move the ratchet wheel i3 and with it the rotary selector 2 by one tooth and connect the port 29 with the next pipe line.

What l` clan i is:

l. A grease pump the outlet of which is adapted to be connected in'a pre-determined ysequence to each of a number of pipe lines leading to the parts to be lubricated, and comprising a pump body, a lubricant receiving cylinder within said pump body, a piston and piston rod slidable in said cylnder, the piston rod extending externally of the pump body to form means for actuating the piston, a valved outlet from said cylinder, a rotatable pipe line selector, within the pump body, and communicating with said cylinder, a number of pipe lines, a ratchet mechanism fast with the selector and within the pump body, a pawl pivotally mounted for actuation by said piston rod for engagement with said ratchet mechanism, so as positively to move the selector, step by step, a pre-determined distance governed by said pawl and ratchet mechanism to place the selector outlet successively in communication with one of the pipe lines, leading to the parts to be lubricated, so that lubricant is forced into each pipe line in turn.

2. A pump as claimed in claim 1 wherein the lubricant receiving cylinder is fed from an accumulator containing a spring loaded piston, a nonreturn valve being provided in the outlet from said cylinder.

3. A grease pump comprising a main body, a lubricant cylinder within said body, a piston slidable in the cylinder, a piston operating rod extending from said body, a lubricant inlet to said cylinder, a Valved outlet from said cylinder, means in said body for receiving the inlet end of each of a series of pipe lines leading to the points to be lubricated, a pipe line selector rotatably mounted within said body adjacent said lastnamed means and having a passageway in communication with said cylinder, through said outlet, the outlet of said passageway being arranged to successively communicate with individual pipe lines as the selector is rotated, a ratchet fast with said selector and within said pump body, a spring biassed yoke fulcrumed intermediate its ends in said body, adjacent said piston rod, a pawl on said yoke, adapted for engagement with said ratchet, cri-acting cam elements on said piston rod and yoke respectively, for rocking the latter on its iulcrum, against the force of said biassing spring, upon inward longitudinal movement of the piston, whereby said pawl is positioned for engagement with a succeeding tooth on said ratchet, the return movement of said piston releasing the yoke and causing the rotation of said selector to its next position.

, il. A pump as claimed in claim 3 wherein one of co-acting cam elements comprises a collar fixed on said piston rod and having a projection which operatively engages a complementary cam element carried by said yoke.

5. A pump as claimed in claim 3 wherein said yoke surrounds said piston and is fulcrumed intermediate its ends in said body, on an axis transverse to that of said piston, one of said co-acting cam elements comprising a collar nxed on said piston rod and having a projection which operatively engages a complementary cam element carried by said yoke.

v HARRY BALSHAW CALDWELL.

REFERENCES CTED The following references are of record in the ile of this patent:

UNITED STATES PATENTS Number Name Date 1,811,958 Murphy June 30, 1931 2,420,970 Parker May 20, 1947 FOREIGN PATENTS Number Country Date 605,601 France Feb. 20, y1926 386,131 Great Britain Jan. 12, 1933

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